btf.c

   1// SPDX-License-Identifier: GPL-2.0
   2/* Copyright (c) 2018 Facebook */
   3
   4#include <uapi/linux/btf.h>
   5#include <uapi/linux/bpf.h>
   6#include <uapi/linux/bpf_perf_event.h>
   7#include <uapi/linux/types.h>
   8#include <linux/seq_file.h>
   9#include <linux/compiler.h>
  10#include <linux/ctype.h>
  11#include <linux/errno.h>
  12#include <linux/slab.h>
  13#include <linux/anon_inodes.h>
  14#include <linux/file.h>
  15#include <linux/uaccess.h>
  16#include <linux/kernel.h>
  17#include <linux/idr.h>
  18#include <linux/sort.h>
  19#include <linux/bpf_verifier.h>
  20#include <linux/btf.h>
  21#include <linux/btf_ids.h>
  22#include <linux/bpf.h>
  23#include <linux/bpf_lsm.h>
  24#include <linux/skmsg.h>
  25#include <linux/perf_event.h>
  26#include <linux/bsearch.h>
  27#include <linux/kobject.h>
  28#include <linux/sysfs.h>
  29#include <linux/overflow.h>
  30
  31#include <net/netfilter/nf_bpf_link.h>
  32
  33#include <net/sock.h>
  34#include <net/xdp.h>
  35#include "../tools/lib/bpf/relo_core.h"
  36
  37/* BTF (BPF Type Format) is the meta data format which describes
  38 * the data types of BPF program/map.  Hence, it basically focus
  39 * on the C programming language which the modern BPF is primary
  40 * using.
  41 *
  42 * ELF Section:
  43 * ~~~~~~~~~~~
  44 * The BTF data is stored under the ".BTF" ELF section
  45 *
  46 * struct btf_type:
  47 * ~~~~~~~~~~~~~~~
  48 * Each 'struct btf_type' object describes a C data type.
  49 * Depending on the type it is describing, a 'struct btf_type'
  50 * object may be followed by more data.  F.e.
  51 * To describe an array, 'struct btf_type' is followed by
  52 * 'struct btf_array'.
  53 *
  54 * 'struct btf_type' and any extra data following it are
  55 * 4 bytes aligned.
  56 *
  57 * Type section:
  58 * ~~~~~~~~~~~~~
  59 * The BTF type section contains a list of 'struct btf_type' objects.
  60 * Each one describes a C type.  Recall from the above section
  61 * that a 'struct btf_type' object could be immediately followed by extra
  62 * data in order to describe some particular C types.
  63 *
  64 * type_id:
  65 * ~~~~~~~
  66 * Each btf_type object is identified by a type_id.  The type_id
  67 * is implicitly implied by the location of the btf_type object in
  68 * the BTF type section.  The first one has type_id 1.  The second
  69 * one has type_id 2...etc.  Hence, an earlier btf_type has
  70 * a smaller type_id.
  71 *
  72 * A btf_type object may refer to another btf_type object by using
  73 * type_id (i.e. the "type" in the "struct btf_type").
  74 *
  75 * NOTE that we cannot assume any reference-order.
  76 * A btf_type object can refer to an earlier btf_type object
  77 * but it can also refer to a later btf_type object.
  78 *
  79 * For example, to describe "const void *".  A btf_type
  80 * object describing "const" may refer to another btf_type
  81 * object describing "void *".  This type-reference is done
  82 * by specifying type_id:
  83 *
  84 * [1] CONST (anon) type_id=2
  85 * [2] PTR (anon) type_id=0
  86 *
  87 * The above is the btf_verifier debug log:
  88 *   - Each line started with "[?]" is a btf_type object
  89 *   - [?] is the type_id of the btf_type object.
  90 *   - CONST/PTR is the BTF_KIND_XXX
  91 *   - "(anon)" is the name of the type.  It just
  92 *     happens that CONST and PTR has no name.
  93 *   - type_id=XXX is the 'u32 type' in btf_type
  94 *
  95 * NOTE: "void" has type_id 0
  96 *
  97 * String section:
  98 * ~~~~~~~~~~~~~~
  99 * The BTF string section contains the names used by the type section.
 100 * Each string is referred by an "offset" from the beginning of the
 101 * string section.
 102 *
 103 * Each string is '\0' terminated.
 104 *
 105 * The first character in the string section must be '\0'
 106 * which is used to mean 'anonymous'. Some btf_type may not
 107 * have a name.
 108 */
 109
 110/* BTF verification:
 111 *
 112 * To verify BTF data, two passes are needed.
 113 *
 114 * Pass #1
 115 * ~~~~~~~
 116 * The first pass is to collect all btf_type objects to
 117 * an array: "btf->types".
 118 *
 119 * Depending on the C type that a btf_type is describing,
 120 * a btf_type may be followed by extra data.  We don't know
 121 * how many btf_type is there, and more importantly we don't
 122 * know where each btf_type is located in the type section.
 123 *
 124 * Without knowing the location of each type_id, most verifications
 125 * cannot be done.  e.g. an earlier btf_type may refer to a later
 126 * btf_type (recall the "const void *" above), so we cannot
 127 * check this type-reference in the first pass.
 128 *
 129 * In the first pass, it still does some verifications (e.g.
 130 * checking the name is a valid offset to the string section).
 131 *
 132 * Pass #2
 133 * ~~~~~~~
 134 * The main focus is to resolve a btf_type that is referring
 135 * to another type.
 136 *
 137 * We have to ensure the referring type:
 138 * 1) does exist in the BTF (i.e. in btf->types[])
 139 * 2) does not cause a loop:
 140 *	struct A {
 141 *		struct B b;
 142 *	};
 143 *
 144 *	struct B {
 145 *		struct A a;
 146 *	};
 147 *
 148 * btf_type_needs_resolve() decides if a btf_type needs
 149 * to be resolved.
 150 *
 151 * The needs_resolve type implements the "resolve()" ops which
 152 * essentially does a DFS and detects backedge.
 153 *
 154 * During resolve (or DFS), different C types have different
 155 * "RESOLVED" conditions.
 156 *
 157 * When resolving a BTF_KIND_STRUCT, we need to resolve all its
 158 * members because a member is always referring to another
 159 * type.  A struct's member can be treated as "RESOLVED" if
 160 * it is referring to a BTF_KIND_PTR.  Otherwise, the
 161 * following valid C struct would be rejected:
 162 *
 163 *	struct A {
 164 *		int m;
 165 *		struct A *a;
 166 *	};
 167 *
 168 * When resolving a BTF_KIND_PTR, it needs to keep resolving if
 169 * it is referring to another BTF_KIND_PTR.  Otherwise, we cannot
 170 * detect a pointer loop, e.g.:
 171 * BTF_KIND_CONST -> BTF_KIND_PTR -> BTF_KIND_CONST -> BTF_KIND_PTR +
 172 *                        ^                                         |
 173 *                        +-----------------------------------------+
 174 *
 175 */
 176
 177#define BITS_PER_U128 (sizeof(u64) * BITS_PER_BYTE * 2)
 178#define BITS_PER_BYTE_MASK (BITS_PER_BYTE - 1)
 179#define BITS_PER_BYTE_MASKED(bits) ((bits) & BITS_PER_BYTE_MASK)
 180#define BITS_ROUNDDOWN_BYTES(bits) ((bits) >> 3)
 181#define BITS_ROUNDUP_BYTES(bits) \
 182	(BITS_ROUNDDOWN_BYTES(bits) + !!BITS_PER_BYTE_MASKED(bits))
 183
 184#define BTF_INFO_MASK 0x9f00ffff
 185#define BTF_INT_MASK 0x0fffffff
 186#define BTF_TYPE_ID_VALID(type_id) ((type_id) <= BTF_MAX_TYPE)
 187#define BTF_STR_OFFSET_VALID(name_off) ((name_off) <= BTF_MAX_NAME_OFFSET)
 188
 189/* 16MB for 64k structs and each has 16 members and
 190 * a few MB spaces for the string section.
 191 * The hard limit is S32_MAX.
 192 */
 193#define BTF_MAX_SIZE (16 * 1024 * 1024)
 194
 195#define for_each_member_from(i, from, struct_type, member)		\
 196	for (i = from, member = btf_type_member(struct_type) + from;	\
 197	     i < btf_type_vlen(struct_type);				\
 198	     i++, member++)
 199
 200#define for_each_vsi_from(i, from, struct_type, member)				\
 201	for (i = from, member = btf_type_var_secinfo(struct_type) + from;	\
 202	     i < btf_type_vlen(struct_type);					\
 203	     i++, member++)
 204
 205DEFINE_IDR(btf_idr);
 206DEFINE_SPINLOCK(btf_idr_lock);
 207
 208enum btf_kfunc_hook {
 209	BTF_KFUNC_HOOK_COMMON,
 210	BTF_KFUNC_HOOK_XDP,
 211	BTF_KFUNC_HOOK_TC,
 212	BTF_KFUNC_HOOK_STRUCT_OPS,
 213	BTF_KFUNC_HOOK_TRACING,
 214	BTF_KFUNC_HOOK_SYSCALL,
 215	BTF_KFUNC_HOOK_FMODRET,
 216	BTF_KFUNC_HOOK_CGROUP,
 217	BTF_KFUNC_HOOK_SCHED_ACT,
 218	BTF_KFUNC_HOOK_SK_SKB,
 219	BTF_KFUNC_HOOK_SOCKET_FILTER,
 220	BTF_KFUNC_HOOK_LWT,
 221	BTF_KFUNC_HOOK_NETFILTER,
 222	BTF_KFUNC_HOOK_KPROBE,
 223	BTF_KFUNC_HOOK_MAX,
 224};
 225
 226enum {
 227	BTF_KFUNC_SET_MAX_CNT = 256,
 228	BTF_DTOR_KFUNC_MAX_CNT = 256,
 229	BTF_KFUNC_FILTER_MAX_CNT = 16,
 230};
 231
 232struct btf_kfunc_hook_filter {
 233	btf_kfunc_filter_t filters[BTF_KFUNC_FILTER_MAX_CNT];
 234	u32 nr_filters;
 235};
 236
 237struct btf_kfunc_set_tab {
 238	struct btf_id_set8 *sets[BTF_KFUNC_HOOK_MAX];
 239	struct btf_kfunc_hook_filter hook_filters[BTF_KFUNC_HOOK_MAX];
 240};
 241
 242struct btf_id_dtor_kfunc_tab {
 243	u32 cnt;
 244	struct btf_id_dtor_kfunc dtors[];
 245};
 246
 247struct btf_struct_ops_tab {
 248	u32 cnt;
 249	u32 capacity;
 250	struct bpf_struct_ops_desc ops[];
 251};
 252
 253struct btf {
 254	void *data;
 255	struct btf_type **types;
 256	u32 *resolved_ids;
 257	u32 *resolved_sizes;
 258	const char *strings;
 259	void *nohdr_data;
 260	struct btf_header hdr;
 261	u32 nr_types; /* includes VOID for base BTF */
 262	u32 types_size;
 263	u32 data_size;
 264	refcount_t refcnt;
 265	u32 id;
 266	struct rcu_head rcu;
 267	struct btf_kfunc_set_tab *kfunc_set_tab;
 268	struct btf_id_dtor_kfunc_tab *dtor_kfunc_tab;
 269	struct btf_struct_metas *struct_meta_tab;
 270	struct btf_struct_ops_tab *struct_ops_tab;
 271
 272	/* split BTF support */
 273	struct btf *base_btf;
 274	u32 start_id; /* first type ID in this BTF (0 for base BTF) */
 275	u32 start_str_off; /* first string offset (0 for base BTF) */
 276	char name[MODULE_NAME_LEN];
 277	bool kernel_btf;
 278	__u32 *base_id_map; /* map from distilled base BTF -> vmlinux BTF ids */
 279};
 280
 281enum verifier_phase {
 282	CHECK_META,
 283	CHECK_TYPE,
 284};
 285
 286struct resolve_vertex {
 287	const struct btf_type *t;
 288	u32 type_id;
 289	u16 next_member;
 290};
 291
 292enum visit_state {
 293	NOT_VISITED,
 294	VISITED,
 295	RESOLVED,
 296};
 297
 298enum resolve_mode {
 299	RESOLVE_TBD,	/* To Be Determined */
 300	RESOLVE_PTR,	/* Resolving for Pointer */
 301	RESOLVE_STRUCT_OR_ARRAY,	/* Resolving for struct/union
 302					 * or array
 303					 */
 304};
 305
 306#define MAX_RESOLVE_DEPTH 32
 307
 308struct btf_sec_info {
 309	u32 off;
 310	u32 len;
 311};
 312
 313struct btf_verifier_env {
 314	struct btf *btf;
 315	u8 *visit_states;
 316	struct resolve_vertex stack[MAX_RESOLVE_DEPTH];
 317	struct bpf_verifier_log log;
 318	u32 log_type_id;
 319	u32 top_stack;
 320	enum verifier_phase phase;
 321	enum resolve_mode resolve_mode;
 322};
 323
 324static const char * const btf_kind_str[NR_BTF_KINDS] = {
 325	[BTF_KIND_UNKN]		= "UNKNOWN",
 326	[BTF_KIND_INT]		= "INT",
 327	[BTF_KIND_PTR]		= "PTR",
 328	[BTF_KIND_ARRAY]	= "ARRAY",
 329	[BTF_KIND_STRUCT]	= "STRUCT",
 330	[BTF_KIND_UNION]	= "UNION",
 331	[BTF_KIND_ENUM]		= "ENUM",
 332	[BTF_KIND_FWD]		= "FWD",
 333	[BTF_KIND_TYPEDEF]	= "TYPEDEF",
 334	[BTF_KIND_VOLATILE]	= "VOLATILE",
 335	[BTF_KIND_CONST]	= "CONST",
 336	[BTF_KIND_RESTRICT]	= "RESTRICT",
 337	[BTF_KIND_FUNC]		= "FUNC",
 338	[BTF_KIND_FUNC_PROTO]	= "FUNC_PROTO",
 339	[BTF_KIND_VAR]		= "VAR",
 340	[BTF_KIND_DATASEC]	= "DATASEC",
 341	[BTF_KIND_FLOAT]	= "FLOAT",
 342	[BTF_KIND_DECL_TAG]	= "DECL_TAG",
 343	[BTF_KIND_TYPE_TAG]	= "TYPE_TAG",
 344	[BTF_KIND_ENUM64]	= "ENUM64",
 345};
 346
 347const char *btf_type_str(const struct btf_type *t)
 348{
 349	return btf_kind_str[BTF_INFO_KIND(t->info)];
 350}
 351
 352/* Chunk size we use in safe copy of data to be shown. */
 353#define BTF_SHOW_OBJ_SAFE_SIZE		32
 354
 355/*
 356 * This is the maximum size of a base type value (equivalent to a
 357 * 128-bit int); if we are at the end of our safe buffer and have
 358 * less than 16 bytes space we can't be assured of being able
 359 * to copy the next type safely, so in such cases we will initiate
 360 * a new copy.
 361 */
 362#define BTF_SHOW_OBJ_BASE_TYPE_SIZE	16
 363
 364/* Type name size */
 365#define BTF_SHOW_NAME_SIZE		80
 366
 367/*
 368 * The suffix of a type that indicates it cannot alias another type when
 369 * comparing BTF IDs for kfunc invocations.
 370 */
 371#define NOCAST_ALIAS_SUFFIX		"___init"
 372
 373/*
 374 * Common data to all BTF show operations. Private show functions can add
 375 * their own data to a structure containing a struct btf_show and consult it
 376 * in the show callback.  See btf_type_show() below.
 377 *
 378 * One challenge with showing nested data is we want to skip 0-valued
 379 * data, but in order to figure out whether a nested object is all zeros
 380 * we need to walk through it.  As a result, we need to make two passes
 381 * when handling structs, unions and arrays; the first path simply looks
 382 * for nonzero data, while the second actually does the display.  The first
 383 * pass is signalled by show->state.depth_check being set, and if we
 384 * encounter a non-zero value we set show->state.depth_to_show to
 385 * the depth at which we encountered it.  When we have completed the
 386 * first pass, we will know if anything needs to be displayed if
 387 * depth_to_show > depth.  See btf_[struct,array]_show() for the
 388 * implementation of this.
 389 *
 390 * Another problem is we want to ensure the data for display is safe to
 391 * access.  To support this, the anonymous "struct {} obj" tracks the data
 392 * object and our safe copy of it.  We copy portions of the data needed
 393 * to the object "copy" buffer, but because its size is limited to
 394 * BTF_SHOW_OBJ_COPY_LEN bytes, multiple copies may be required as we
 395 * traverse larger objects for display.
 396 *
 397 * The various data type show functions all start with a call to
 398 * btf_show_start_type() which returns a pointer to the safe copy
 399 * of the data needed (or if BTF_SHOW_UNSAFE is specified, to the
 400 * raw data itself).  btf_show_obj_safe() is responsible for
 401 * using copy_from_kernel_nofault() to update the safe data if necessary
 402 * as we traverse the object's data.  skbuff-like semantics are
 403 * used:
 404 *
 405 * - obj.head points to the start of the toplevel object for display
 406 * - obj.size is the size of the toplevel object
 407 * - obj.data points to the current point in the original data at
 408 *   which our safe data starts.  obj.data will advance as we copy
 409 *   portions of the data.
 410 *
 411 * In most cases a single copy will suffice, but larger data structures
 412 * such as "struct task_struct" will require many copies.  The logic in
 413 * btf_show_obj_safe() handles the logic that determines if a new
 414 * copy_from_kernel_nofault() is needed.
 415 */
 416struct btf_show {
 417	u64 flags;
 418	void *target;	/* target of show operation (seq file, buffer) */
 419	__printf(2, 0) void (*showfn)(struct btf_show *show, const char *fmt, va_list args);
 420	const struct btf *btf;
 421	/* below are used during iteration */
 422	struct {
 423		u8 depth;
 424		u8 depth_to_show;
 425		u8 depth_check;
 426		u8 array_member:1,
 427		   array_terminated:1;
 428		u16 array_encoding;
 429		u32 type_id;
 430		int status;			/* non-zero for error */
 431		const struct btf_type *type;
 432		const struct btf_member *member;
 433		char name[BTF_SHOW_NAME_SIZE];	/* space for member name/type */
 434	} state;
 435	struct {
 436		u32 size;
 437		void *head;
 438		void *data;
 439		u8 safe[BTF_SHOW_OBJ_SAFE_SIZE];
 440	} obj;
 441};
 442
 443struct btf_kind_operations {
 444	s32 (*check_meta)(struct btf_verifier_env *env,
 445			  const struct btf_type *t,
 446			  u32 meta_left);
 447	int (*resolve)(struct btf_verifier_env *env,
 448		       const struct resolve_vertex *v);
 449	int (*check_member)(struct btf_verifier_env *env,
 450			    const struct btf_type *struct_type,
 451			    const struct btf_member *member,
 452			    const struct btf_type *member_type);
 453	int (*check_kflag_member)(struct btf_verifier_env *env,
 454				  const struct btf_type *struct_type,
 455				  const struct btf_member *member,
 456				  const struct btf_type *member_type);
 457	void (*log_details)(struct btf_verifier_env *env,
 458			    const struct btf_type *t);
 459	void (*show)(const struct btf *btf, const struct btf_type *t,
 460			 u32 type_id, void *data, u8 bits_offsets,
 461			 struct btf_show *show);
 462};
 463
 464static const struct btf_kind_operations * const kind_ops[NR_BTF_KINDS];
 465static struct btf_type btf_void;
 466
 467static int btf_resolve(struct btf_verifier_env *env,
 468		       const struct btf_type *t, u32 type_id);
 469
 470static int btf_func_check(struct btf_verifier_env *env,
 471			  const struct btf_type *t);
 472
 473static bool btf_type_is_modifier(const struct btf_type *t)
 474{
 475	/* Some of them is not strictly a C modifier
 476	 * but they are grouped into the same bucket
 477	 * for BTF concern:
 478	 *   A type (t) that refers to another
 479	 *   type through t->type AND its size cannot
 480	 *   be determined without following the t->type.
 481	 *
 482	 * ptr does not fall into this bucket
 483	 * because its size is always sizeof(void *).
 484	 */
 485	switch (BTF_INFO_KIND(t->info)) {
 486	case BTF_KIND_TYPEDEF:
 487	case BTF_KIND_VOLATILE:
 488	case BTF_KIND_CONST:
 489	case BTF_KIND_RESTRICT:
 490	case BTF_KIND_TYPE_TAG:
 491		return true;
 492	}
 493
 494	return false;
 495}
 496
 497bool btf_type_is_void(const struct btf_type *t)
 498{
 499	return t == &btf_void;
 500}
 501
 502static bool btf_type_is_datasec(const struct btf_type *t)
 503{
 504	return BTF_INFO_KIND(t->info) == BTF_KIND_DATASEC;
 505}
 506
 507static bool btf_type_is_decl_tag(const struct btf_type *t)
 508{
 509	return BTF_INFO_KIND(t->info) == BTF_KIND_DECL_TAG;
 510}
 511
 512static bool btf_type_nosize(const struct btf_type *t)
 513{
 514	return btf_type_is_void(t) || btf_type_is_fwd(t) ||
 515	       btf_type_is_func(t) || btf_type_is_func_proto(t) ||
 516	       btf_type_is_decl_tag(t);
 517}
 518
 519static bool btf_type_nosize_or_null(const struct btf_type *t)
 520{
 521	return !t || btf_type_nosize(t);
 522}
 523
 524static bool btf_type_is_decl_tag_target(const struct btf_type *t)
 525{
 526	return btf_type_is_func(t) || btf_type_is_struct(t) ||
 527	       btf_type_is_var(t) || btf_type_is_typedef(t);
 528}
 529
 530bool btf_is_vmlinux(const struct btf *btf)
 531{
 532	return btf->kernel_btf && !btf->base_btf;
 533}
 534
 535u32 btf_nr_types(const struct btf *btf)
 536{
 537	u32 total = 0;
 538
 539	while (btf) {
 540		total += btf->nr_types;
 541		btf = btf->base_btf;
 542	}
 543
 544	return total;
 545}
 546
 547s32 btf_find_by_name_kind(const struct btf *btf, const char *name, u8 kind)
 548{
 549	const struct btf_type *t;
 550	const char *tname;
 551	u32 i, total;
 552
 553	total = btf_nr_types(btf);
 554	for (i = 1; i < total; i++) {
 555		t = btf_type_by_id(btf, i);
 556		if (BTF_INFO_KIND(t->info) != kind)
 557			continue;
 558
 559		tname = btf_name_by_offset(btf, t->name_off);
 560		if (!strcmp(tname, name))
 561			return i;
 562	}
 563
 564	return -ENOENT;
 565}
 566
 567s32 bpf_find_btf_id(const char *name, u32 kind, struct btf **btf_p)
 568{
 569	struct btf *btf;
 570	s32 ret;
 571	int id;
 572
 573	btf = bpf_get_btf_vmlinux();
 574	if (IS_ERR(btf))
 575		return PTR_ERR(btf);
 576	if (!btf)
 577		return -EINVAL;
 578
 579	ret = btf_find_by_name_kind(btf, name, kind);
 580	/* ret is never zero, since btf_find_by_name_kind returns
 581	 * positive btf_id or negative error.
 582	 */
 583	if (ret > 0) {
 584		btf_get(btf);
 585		*btf_p = btf;
 586		return ret;
 587	}
 588
 589	/* If name is not found in vmlinux's BTF then search in module's BTFs */
 590	spin_lock_bh(&btf_idr_lock);
 591	idr_for_each_entry(&btf_idr, btf, id) {
 592		if (!btf_is_module(btf))
 593			continue;
 594		/* linear search could be slow hence unlock/lock
 595		 * the IDR to avoiding holding it for too long
 596		 */
 597		btf_get(btf);
 598		spin_unlock_bh(&btf_idr_lock);
 599		ret = btf_find_by_name_kind(btf, name, kind);
 600		if (ret > 0) {
 601			*btf_p = btf;
 602			return ret;
 603		}
 604		btf_put(btf);
 605		spin_lock_bh(&btf_idr_lock);
 606	}
 607	spin_unlock_bh(&btf_idr_lock);
 608	return ret;
 609}
 610EXPORT_SYMBOL_GPL(bpf_find_btf_id);
 611
 612const struct btf_type *btf_type_skip_modifiers(const struct btf *btf,
 613					       u32 id, u32 *res_id)
 614{
 615	const struct btf_type *t = btf_type_by_id(btf, id);
 616
 617	while (btf_type_is_modifier(t)) {
 618		id = t->type;
 619		t = btf_type_by_id(btf, t->type);
 620	}
 621
 622	if (res_id)
 623		*res_id = id;
 624
 625	return t;
 626}
 627
 628const struct btf_type *btf_type_resolve_ptr(const struct btf *btf,
 629					    u32 id, u32 *res_id)
 630{
 631	const struct btf_type *t;
 632
 633	t = btf_type_skip_modifiers(btf, id, NULL);
 634	if (!btf_type_is_ptr(t))
 635		return NULL;
 636
 637	return btf_type_skip_modifiers(btf, t->type, res_id);
 638}
 639
 640const struct btf_type *btf_type_resolve_func_ptr(const struct btf *btf,
 641						 u32 id, u32 *res_id)
 642{
 643	const struct btf_type *ptype;
 644
 645	ptype = btf_type_resolve_ptr(btf, id, res_id);
 646	if (ptype && btf_type_is_func_proto(ptype))
 647		return ptype;
 648
 649	return NULL;
 650}
 651
 652/* Types that act only as a source, not sink or intermediate
 653 * type when resolving.
 654 */
 655static bool btf_type_is_resolve_source_only(const struct btf_type *t)
 656{
 657	return btf_type_is_var(t) ||
 658	       btf_type_is_decl_tag(t) ||
 659	       btf_type_is_datasec(t);
 660}
 661
 662/* What types need to be resolved?
 663 *
 664 * btf_type_is_modifier() is an obvious one.
 665 *
 666 * btf_type_is_struct() because its member refers to
 667 * another type (through member->type).
 668 *
 669 * btf_type_is_var() because the variable refers to
 670 * another type. btf_type_is_datasec() holds multiple
 671 * btf_type_is_var() types that need resolving.
 672 *
 673 * btf_type_is_array() because its element (array->type)
 674 * refers to another type.  Array can be thought of a
 675 * special case of struct while array just has the same
 676 * member-type repeated by array->nelems of times.
 677 */
 678static bool btf_type_needs_resolve(const struct btf_type *t)
 679{
 680	return btf_type_is_modifier(t) ||
 681	       btf_type_is_ptr(t) ||
 682	       btf_type_is_struct(t) ||
 683	       btf_type_is_array(t) ||
 684	       btf_type_is_var(t) ||
 685	       btf_type_is_func(t) ||
 686	       btf_type_is_decl_tag(t) ||
 687	       btf_type_is_datasec(t);
 688}
 689
 690/* t->size can be used */
 691static bool btf_type_has_size(const struct btf_type *t)
 692{
 693	switch (BTF_INFO_KIND(t->info)) {
 694	case BTF_KIND_INT:
 695	case BTF_KIND_STRUCT:
 696	case BTF_KIND_UNION:
 697	case BTF_KIND_ENUM:
 698	case BTF_KIND_DATASEC:
 699	case BTF_KIND_FLOAT:
 700	case BTF_KIND_ENUM64:
 701		return true;
 702	}
 703
 704	return false;
 705}
 706
 707static const char *btf_int_encoding_str(u8 encoding)
 708{
 709	if (encoding == 0)
 710		return "(none)";
 711	else if (encoding == BTF_INT_SIGNED)
 712		return "SIGNED";
 713	else if (encoding == BTF_INT_CHAR)
 714		return "CHAR";
 715	else if (encoding == BTF_INT_BOOL)
 716		return "BOOL";
 717	else
 718		return "UNKN";
 719}
 720
 721static u32 btf_type_int(const struct btf_type *t)
 722{
 723	return *(u32 *)(t + 1);
 724}
 725
 726static const struct btf_array *btf_type_array(const struct btf_type *t)
 727{
 728	return (const struct btf_array *)(t + 1);
 729}
 730
 731static const struct btf_enum *btf_type_enum(const struct btf_type *t)
 732{
 733	return (const struct btf_enum *)(t + 1);
 734}
 735
 736static const struct btf_var *btf_type_var(const struct btf_type *t)
 737{
 738	return (const struct btf_var *)(t + 1);
 739}
 740
 741static const struct btf_decl_tag *btf_type_decl_tag(const struct btf_type *t)
 742{
 743	return (const struct btf_decl_tag *)(t + 1);
 744}
 745
 746static const struct btf_enum64 *btf_type_enum64(const struct btf_type *t)
 747{
 748	return (const struct btf_enum64 *)(t + 1);
 749}
 750
 751static const struct btf_kind_operations *btf_type_ops(const struct btf_type *t)
 752{
 753	return kind_ops[BTF_INFO_KIND(t->info)];
 754}
 755
 756static bool btf_name_offset_valid(const struct btf *btf, u32 offset)
 757{
 758	if (!BTF_STR_OFFSET_VALID(offset))
 759		return false;
 760
 761	while (offset < btf->start_str_off)
 762		btf = btf->base_btf;
 763
 764	offset -= btf->start_str_off;
 765	return offset < btf->hdr.str_len;
 766}
 767
 768static bool __btf_name_char_ok(char c, bool first)
 769{
 770	if ((first ? !isalpha(c) :
 771		     !isalnum(c)) &&
 772	    c != '_' &&
 773	    c != '.')
 774		return false;
 775	return true;
 776}
 777
 778const char *btf_str_by_offset(const struct btf *btf, u32 offset)
 779{
 780	while (offset < btf->start_str_off)
 781		btf = btf->base_btf;
 782
 783	offset -= btf->start_str_off;
 784	if (offset < btf->hdr.str_len)
 785		return &btf->strings[offset];
 786
 787	return NULL;
 788}
 789
 790static bool btf_name_valid_identifier(const struct btf *btf, u32 offset)
 791{
 792	/* offset must be valid */
 793	const char *src = btf_str_by_offset(btf, offset);
 794	const char *src_limit;
 795
 796	if (!__btf_name_char_ok(*src, true))
 797		return false;
 798
 799	/* set a limit on identifier length */
 800	src_limit = src + KSYM_NAME_LEN;
 801	src++;
 802	while (*src && src < src_limit) {
 803		if (!__btf_name_char_ok(*src, false))
 804			return false;
 805		src++;
 806	}
 807
 808	return !*src;
 809}
 810
 811/* Allow any printable character in DATASEC names */
 812static bool btf_name_valid_section(const struct btf *btf, u32 offset)
 813{
 814	/* offset must be valid */
 815	const char *src = btf_str_by_offset(btf, offset);
 816	const char *src_limit;
 817
 818	if (!*src)
 819		return false;
 820
 821	/* set a limit on identifier length */
 822	src_limit = src + KSYM_NAME_LEN;
 823	while (*src && src < src_limit) {
 824		if (!isprint(*src))
 825			return false;
 826		src++;
 827	}
 828
 829	return !*src;
 830}
 831
 832static const char *__btf_name_by_offset(const struct btf *btf, u32 offset)
 833{
 834	const char *name;
 835
 836	if (!offset)
 837		return "(anon)";
 838
 839	name = btf_str_by_offset(btf, offset);
 840	return name ?: "(invalid-name-offset)";
 841}
 842
 843const char *btf_name_by_offset(const struct btf *btf, u32 offset)
 844{
 845	return btf_str_by_offset(btf, offset);
 846}
 847
 848const struct btf_type *btf_type_by_id(const struct btf *btf, u32 type_id)
 849{
 850	while (type_id < btf->start_id)
 851		btf = btf->base_btf;
 852
 853	type_id -= btf->start_id;
 854	if (type_id >= btf->nr_types)
 855		return NULL;
 856	return btf->types[type_id];
 857}
 858EXPORT_SYMBOL_GPL(btf_type_by_id);
 859
 860/*
 861 * Check that the type @t is a regular int. This means that @t is not
 862 * a bit field and it has the same size as either of u8/u16/u32/u64
 863 * or __int128. If @expected_size is not zero, then size of @t should
 864 * be the same. A caller should already have checked that the type @t
 865 * is an integer.
 866 */
 867static bool __btf_type_int_is_regular(const struct btf_type *t, size_t expected_size)
 868{
 869	u32 int_data = btf_type_int(t);
 870	u8 nr_bits = BTF_INT_BITS(int_data);
 871	u8 nr_bytes = BITS_ROUNDUP_BYTES(nr_bits);
 872
 873	return BITS_PER_BYTE_MASKED(nr_bits) == 0 &&
 874	       BTF_INT_OFFSET(int_data) == 0 &&
 875	       (nr_bytes <= 16 && is_power_of_2(nr_bytes)) &&
 876	       (expected_size == 0 || nr_bytes == expected_size);
 877}
 878
 879static bool btf_type_int_is_regular(const struct btf_type *t)
 880{
 881	return __btf_type_int_is_regular(t, 0);
 882}
 883
 884bool btf_type_is_i32(const struct btf_type *t)
 885{
 886	return btf_type_is_int(t) && __btf_type_int_is_regular(t, 4);
 887}
 888
 889bool btf_type_is_i64(const struct btf_type *t)
 890{
 891	return btf_type_is_int(t) && __btf_type_int_is_regular(t, 8);
 892}
 893
 894bool btf_type_is_primitive(const struct btf_type *t)
 895{
 896	return (btf_type_is_int(t) && btf_type_int_is_regular(t)) ||
 897	       btf_is_any_enum(t);
 898}
 899
 900/*
 901 * Check that given struct member is a regular int with expected
 902 * offset and size.
 903 */
 904bool btf_member_is_reg_int(const struct btf *btf, const struct btf_type *s,
 905			   const struct btf_member *m,
 906			   u32 expected_offset, u32 expected_size)
 907{
 908	const struct btf_type *t;
 909	u32 id, int_data;
 910	u8 nr_bits;
 911
 912	id = m->type;
 913	t = btf_type_id_size(btf, &id, NULL);
 914	if (!t || !btf_type_is_int(t))
 915		return false;
 916
 917	int_data = btf_type_int(t);
 918	nr_bits = BTF_INT_BITS(int_data);
 919	if (btf_type_kflag(s)) {
 920		u32 bitfield_size = BTF_MEMBER_BITFIELD_SIZE(m->offset);
 921		u32 bit_offset = BTF_MEMBER_BIT_OFFSET(m->offset);
 922
 923		/* if kflag set, int should be a regular int and
 924		 * bit offset should be at byte boundary.
 925		 */
 926		return !bitfield_size &&
 927		       BITS_ROUNDUP_BYTES(bit_offset) == expected_offset &&
 928		       BITS_ROUNDUP_BYTES(nr_bits) == expected_size;
 929	}
 930
 931	if (BTF_INT_OFFSET(int_data) ||
 932	    BITS_PER_BYTE_MASKED(m->offset) ||
 933	    BITS_ROUNDUP_BYTES(m->offset) != expected_offset ||
 934	    BITS_PER_BYTE_MASKED(nr_bits) ||
 935	    BITS_ROUNDUP_BYTES(nr_bits) != expected_size)
 936		return false;
 937
 938	return true;
 939}
 940
 941/* Similar to btf_type_skip_modifiers() but does not skip typedefs. */
 942static const struct btf_type *btf_type_skip_qualifiers(const struct btf *btf,
 943						       u32 id)
 944{
 945	const struct btf_type *t = btf_type_by_id(btf, id);
 946
 947	while (btf_type_is_modifier(t) &&
 948	       BTF_INFO_KIND(t->info) != BTF_KIND_TYPEDEF) {
 949		t = btf_type_by_id(btf, t->type);
 950	}
 951
 952	return t;
 953}
 954
 955#define BTF_SHOW_MAX_ITER	10
 956
 957#define BTF_KIND_BIT(kind)	(1ULL << kind)
 958
 959/*
 960 * Populate show->state.name with type name information.
 961 * Format of type name is
 962 *
 963 * [.member_name = ] (type_name)
 964 */
 965static const char *btf_show_name(struct btf_show *show)
 966{
 967	/* BTF_MAX_ITER array suffixes "[]" */
 968	const char *array_suffixes = "[][][][][][][][][][]";
 969	const char *array_suffix = &array_suffixes[strlen(array_suffixes)];
 970	/* BTF_MAX_ITER pointer suffixes "*" */
 971	const char *ptr_suffixes = "**********";
 972	const char *ptr_suffix = &ptr_suffixes[strlen(ptr_suffixes)];
 973	const char *name = NULL, *prefix = "", *parens = "";
 974	const struct btf_member *m = show->state.member;
 975	const struct btf_type *t;
 976	const struct btf_array *array;
 977	u32 id = show->state.type_id;
 978	const char *member = NULL;
 979	bool show_member = false;
 980	u64 kinds = 0;
 981	int i;
 982
 983	show->state.name[0] = '\0';
 984
 985	/*
 986	 * Don't show type name if we're showing an array member;
 987	 * in that case we show the array type so don't need to repeat
 988	 * ourselves for each member.
 989	 */
 990	if (show->state.array_member)
 991		return "";
 992
 993	/* Retrieve member name, if any. */
 994	if (m) {
 995		member = btf_name_by_offset(show->btf, m->name_off);
 996		show_member = strlen(member) > 0;
 997		id = m->type;
 998	}
 999
1000	/*
1001	 * Start with type_id, as we have resolved the struct btf_type *
1002	 * via btf_modifier_show() past the parent typedef to the child
1003	 * struct, int etc it is defined as.  In such cases, the type_id
1004	 * still represents the starting type while the struct btf_type *
1005	 * in our show->state points at the resolved type of the typedef.
1006	 */
1007	t = btf_type_by_id(show->btf, id);
1008	if (!t)
1009		return "";
1010
1011	/*
1012	 * The goal here is to build up the right number of pointer and
1013	 * array suffixes while ensuring the type name for a typedef
1014	 * is represented.  Along the way we accumulate a list of
1015	 * BTF kinds we have encountered, since these will inform later
1016	 * display; for example, pointer types will not require an
1017	 * opening "{" for struct, we will just display the pointer value.
1018	 *
1019	 * We also want to accumulate the right number of pointer or array
1020	 * indices in the format string while iterating until we get to
1021	 * the typedef/pointee/array member target type.
1022	 *
1023	 * We start by pointing at the end of pointer and array suffix
1024	 * strings; as we accumulate pointers and arrays we move the pointer
1025	 * or array string backwards so it will show the expected number of
1026	 * '*' or '[]' for the type.  BTF_SHOW_MAX_ITER of nesting of pointers
1027	 * and/or arrays and typedefs are supported as a precaution.
1028	 *
1029	 * We also want to get typedef name while proceeding to resolve
1030	 * type it points to so that we can add parentheses if it is a
1031	 * "typedef struct" etc.
1032	 */
1033	for (i = 0; i < BTF_SHOW_MAX_ITER; i++) {
1034
1035		switch (BTF_INFO_KIND(t->info)) {
1036		case BTF_KIND_TYPEDEF:
1037			if (!name)
1038				name = btf_name_by_offset(show->btf,
1039							       t->name_off);
1040			kinds |= BTF_KIND_BIT(BTF_KIND_TYPEDEF);
1041			id = t->type;
1042			break;
1043		case BTF_KIND_ARRAY:
1044			kinds |= BTF_KIND_BIT(BTF_KIND_ARRAY);
1045			parens = "[";
1046			if (!t)
1047				return "";
1048			array = btf_type_array(t);
1049			if (array_suffix > array_suffixes)
1050				array_suffix -= 2;
1051			id = array->type;
1052			break;
1053		case BTF_KIND_PTR:
1054			kinds |= BTF_KIND_BIT(BTF_KIND_PTR);
1055			if (ptr_suffix > ptr_suffixes)
1056				ptr_suffix -= 1;
1057			id = t->type;
1058			break;
1059		default:
1060			id = 0;
1061			break;
1062		}
1063		if (!id)
1064			break;
1065		t = btf_type_skip_qualifiers(show->btf, id);
1066	}
1067	/* We may not be able to represent this type; bail to be safe */
1068	if (i == BTF_SHOW_MAX_ITER)
1069		return "";
1070
1071	if (!name)
1072		name = btf_name_by_offset(show->btf, t->name_off);
1073
1074	switch (BTF_INFO_KIND(t->info)) {
1075	case BTF_KIND_STRUCT:
1076	case BTF_KIND_UNION:
1077		prefix = BTF_INFO_KIND(t->info) == BTF_KIND_STRUCT ?
1078			 "struct" : "union";
1079		/* if it's an array of struct/union, parens is already set */
1080		if (!(kinds & (BTF_KIND_BIT(BTF_KIND_ARRAY))))
1081			parens = "{";
1082		break;
1083	case BTF_KIND_ENUM:
1084	case BTF_KIND_ENUM64:
1085		prefix = "enum";
1086		break;
1087	default:
1088		break;
1089	}
1090
1091	/* pointer does not require parens */
1092	if (kinds & BTF_KIND_BIT(BTF_KIND_PTR))
1093		parens = "";
1094	/* typedef does not require struct/union/enum prefix */
1095	if (kinds & BTF_KIND_BIT(BTF_KIND_TYPEDEF))
1096		prefix = "";
1097
1098	if (!name)
1099		name = "";
1100
1101	/* Even if we don't want type name info, we want parentheses etc */
1102	if (show->flags & BTF_SHOW_NONAME)
1103		snprintf(show->state.name, sizeof(show->state.name), "%s",
1104			 parens);
1105	else
1106		snprintf(show->state.name, sizeof(show->state.name),
1107			 "%s%s%s(%s%s%s%s%s%s)%s",
1108			 /* first 3 strings comprise ".member = " */
1109			 show_member ? "." : "",
1110			 show_member ? member : "",
1111			 show_member ? " = " : "",
1112			 /* ...next is our prefix (struct, enum, etc) */
1113			 prefix,
1114			 strlen(prefix) > 0 && strlen(name) > 0 ? " " : "",
1115			 /* ...this is the type name itself */
1116			 name,
1117			 /* ...suffixed by the appropriate '*', '[]' suffixes */
1118			 strlen(ptr_suffix) > 0 ? " " : "", ptr_suffix,
1119			 array_suffix, parens);
1120
1121	return show->state.name;
1122}
1123
1124static const char *__btf_show_indent(struct btf_show *show)
1125{
1126	const char *indents = "                                ";
1127	const char *indent = &indents[strlen(indents)];
1128
1129	if ((indent - show->state.depth) >= indents)
1130		return indent - show->state.depth;
1131	return indents;
1132}
1133
1134static const char *btf_show_indent(struct btf_show *show)
1135{
1136	return show->flags & BTF_SHOW_COMPACT ? "" : __btf_show_indent(show);
1137}
1138
1139static const char *btf_show_newline(struct btf_show *show)
1140{
1141	return show->flags & BTF_SHOW_COMPACT ? "" : "\n";
1142}
1143
1144static const char *btf_show_delim(struct btf_show *show)
1145{
1146	if (show->state.depth == 0)
1147		return "";
1148
1149	if ((show->flags & BTF_SHOW_COMPACT) && show->state.type &&
1150		BTF_INFO_KIND(show->state.type->info) == BTF_KIND_UNION)
1151		return "|";
1152
1153	return ",";
1154}
1155
1156__printf(2, 3) static void btf_show(struct btf_show *show, const char *fmt, ...)
1157{
1158	va_list args;
1159
1160	if (!show->state.depth_check) {
1161		va_start(args, fmt);
1162		show->showfn(show, fmt, args);
1163		va_end(args);
1164	}
1165}
1166
1167/* Macros are used here as btf_show_type_value[s]() prepends and appends
1168 * format specifiers to the format specifier passed in; these do the work of
1169 * adding indentation, delimiters etc while the caller simply has to specify
1170 * the type value(s) in the format specifier + value(s).
1171 */
1172#define btf_show_type_value(show, fmt, value)				       \
1173	do {								       \
1174		if ((value) != (__typeof__(value))0 ||			       \
1175		    (show->flags & BTF_SHOW_ZERO) ||			       \
1176		    show->state.depth == 0) {				       \
1177			btf_show(show, "%s%s" fmt "%s%s",		       \
1178				 btf_show_indent(show),			       \
1179				 btf_show_name(show),			       \
1180				 value, btf_show_delim(show),		       \
1181				 btf_show_newline(show));		       \
1182			if (show->state.depth > show->state.depth_to_show)     \
1183				show->state.depth_to_show = show->state.depth; \
1184		}							       \
1185	} while (0)
1186
1187#define btf_show_type_values(show, fmt, ...)				       \
1188	do {								       \
1189		btf_show(show, "%s%s" fmt "%s%s", btf_show_indent(show),       \
1190			 btf_show_name(show),				       \
1191			 __VA_ARGS__, btf_show_delim(show),		       \
1192			 btf_show_newline(show));			       \
1193		if (show->state.depth > show->state.depth_to_show)	       \
1194			show->state.depth_to_show = show->state.depth;	       \
1195	} while (0)
1196
1197/* How much is left to copy to safe buffer after @data? */
1198static int btf_show_obj_size_left(struct btf_show *show, void *data)
1199{
1200	return show->obj.head + show->obj.size - data;
1201}
1202
1203/* Is object pointed to by @data of @size already copied to our safe buffer? */
1204static bool btf_show_obj_is_safe(struct btf_show *show, void *data, int size)
1205{
1206	return data >= show->obj.data &&
1207	       (data + size) < (show->obj.data + BTF_SHOW_OBJ_SAFE_SIZE);
1208}
1209
1210/*
1211 * If object pointed to by @data of @size falls within our safe buffer, return
1212 * the equivalent pointer to the same safe data.  Assumes
1213 * copy_from_kernel_nofault() has already happened and our safe buffer is
1214 * populated.
1215 */
1216static void *__btf_show_obj_safe(struct btf_show *show, void *data, int size)
1217{
1218	if (btf_show_obj_is_safe(show, data, size))
1219		return show->obj.safe + (data - show->obj.data);
1220	return NULL;
1221}
1222
1223/*
1224 * Return a safe-to-access version of data pointed to by @data.
1225 * We do this by copying the relevant amount of information
1226 * to the struct btf_show obj.safe buffer using copy_from_kernel_nofault().
1227 *
1228 * If BTF_SHOW_UNSAFE is specified, just return data as-is; no
1229 * safe copy is needed.
1230 *
1231 * Otherwise we need to determine if we have the required amount
1232 * of data (determined by the @data pointer and the size of the
1233 * largest base type we can encounter (represented by
1234 * BTF_SHOW_OBJ_BASE_TYPE_SIZE). Having that much data ensures
1235 * that we will be able to print some of the current object,
1236 * and if more is needed a copy will be triggered.
1237 * Some objects such as structs will not fit into the buffer;
1238 * in such cases additional copies when we iterate over their
1239 * members may be needed.
1240 *
1241 * btf_show_obj_safe() is used to return a safe buffer for
1242 * btf_show_start_type(); this ensures that as we recurse into
1243 * nested types we always have safe data for the given type.
1244 * This approach is somewhat wasteful; it's possible for example
1245 * that when iterating over a large union we'll end up copying the
1246 * same data repeatedly, but the goal is safety not performance.
1247 * We use stack data as opposed to per-CPU buffers because the
1248 * iteration over a type can take some time, and preemption handling
1249 * would greatly complicate use of the safe buffer.
1250 */
1251static void *btf_show_obj_safe(struct btf_show *show,
1252			       const struct btf_type *t,
1253			       void *data)
1254{
1255	const struct btf_type *rt;
1256	int size_left, size;
1257	void *safe = NULL;
1258
1259	if (show->flags & BTF_SHOW_UNSAFE)
1260		return data;
1261
1262	rt = btf_resolve_size(show->btf, t, &size);
1263	if (IS_ERR(rt)) {
1264		show->state.status = PTR_ERR(rt);
1265		return NULL;
1266	}
1267
1268	/*
1269	 * Is this toplevel object? If so, set total object size and
1270	 * initialize pointers.  Otherwise check if we still fall within
1271	 * our safe object data.
1272	 */
1273	if (show->state.depth == 0) {
1274		show->obj.size = size;
1275		show->obj.head = data;
1276	} else {
1277		/*
1278		 * If the size of the current object is > our remaining
1279		 * safe buffer we _may_ need to do a new copy.  However
1280		 * consider the case of a nested struct; it's size pushes
1281		 * us over the safe buffer limit, but showing any individual
1282		 * struct members does not.  In such cases, we don't need
1283		 * to initiate a fresh copy yet; however we definitely need
1284		 * at least BTF_SHOW_OBJ_BASE_TYPE_SIZE bytes left
1285		 * in our buffer, regardless of the current object size.
1286		 * The logic here is that as we resolve types we will
1287		 * hit a base type at some point, and we need to be sure
1288		 * the next chunk of data is safely available to display
1289		 * that type info safely.  We cannot rely on the size of
1290		 * the current object here because it may be much larger
1291		 * than our current buffer (e.g. task_struct is 8k).
1292		 * All we want to do here is ensure that we can print the
1293		 * next basic type, which we can if either
1294		 * - the current type size is within the safe buffer; or
1295		 * - at least BTF_SHOW_OBJ_BASE_TYPE_SIZE bytes are left in
1296		 *   the safe buffer.
1297		 */
1298		safe = __btf_show_obj_safe(show, data,
1299					   min(size,
1300					       BTF_SHOW_OBJ_BASE_TYPE_SIZE));
1301	}
1302
1303	/*
1304	 * We need a new copy to our safe object, either because we haven't
1305	 * yet copied and are initializing safe data, or because the data
1306	 * we want falls outside the boundaries of the safe object.
1307	 */
1308	if (!safe) {
1309		size_left = btf_show_obj_size_left(show, data);
1310		if (size_left > BTF_SHOW_OBJ_SAFE_SIZE)
1311			size_left = BTF_SHOW_OBJ_SAFE_SIZE;
1312		show->state.status = copy_from_kernel_nofault(show->obj.safe,
1313							      data, size_left);
1314		if (!show->state.status) {
1315			show->obj.data = data;
1316			safe = show->obj.safe;
1317		}
1318	}
1319
1320	return safe;
1321}
1322
1323/*
1324 * Set the type we are starting to show and return a safe data pointer
1325 * to be used for showing the associated data.
1326 */
1327static void *btf_show_start_type(struct btf_show *show,
1328				 const struct btf_type *t,
1329				 u32 type_id, void *data)
1330{
1331	show->state.type = t;
1332	show->state.type_id = type_id;
1333	show->state.name[0] = '\0';
1334
1335	return btf_show_obj_safe(show, t, data);
1336}
1337
1338static void btf_show_end_type(struct btf_show *show)
1339{
1340	show->state.type = NULL;
1341	show->state.type_id = 0;
1342	show->state.name[0] = '\0';
1343}
1344
1345static void *btf_show_start_aggr_type(struct btf_show *show,
1346				      const struct btf_type *t,
1347				      u32 type_id, void *data)
1348{
1349	void *safe_data = btf_show_start_type(show, t, type_id, data);
1350
1351	if (!safe_data)
1352		return safe_data;
1353
1354	btf_show(show, "%s%s%s", btf_show_indent(show),
1355		 btf_show_name(show),
1356		 btf_show_newline(show));
1357	show->state.depth++;
1358	return safe_data;
1359}
1360
1361static void btf_show_end_aggr_type(struct btf_show *show,
1362				   const char *suffix)
1363{
1364	show->state.depth--;
1365	btf_show(show, "%s%s%s%s", btf_show_indent(show), suffix,
1366		 btf_show_delim(show), btf_show_newline(show));
1367	btf_show_end_type(show);
1368}
1369
1370static void btf_show_start_member(struct btf_show *show,
1371				  const struct btf_member *m)
1372{
1373	show->state.member = m;
1374}
1375
1376static void btf_show_start_array_member(struct btf_show *show)
1377{
1378	show->state.array_member = 1;
1379	btf_show_start_member(show, NULL);
1380}
1381
1382static void btf_show_end_member(struct btf_show *show)
1383{
1384	show->state.member = NULL;
1385}
1386
1387static void btf_show_end_array_member(struct btf_show *show)
1388{
1389	show->state.array_member = 0;
1390	btf_show_end_member(show);
1391}
1392
1393static void *btf_show_start_array_type(struct btf_show *show,
1394				       const struct btf_type *t,
1395				       u32 type_id,
1396				       u16 array_encoding,
1397				       void *data)
1398{
1399	show->state.array_encoding = array_encoding;
1400	show->state.array_terminated = 0;
1401	return btf_show_start_aggr_type(show, t, type_id, data);
1402}
1403
1404static void btf_show_end_array_type(struct btf_show *show)
1405{
1406	show->state.array_encoding = 0;
1407	show->state.array_terminated = 0;
1408	btf_show_end_aggr_type(show, "]");
1409}
1410
1411static void *btf_show_start_struct_type(struct btf_show *show,
1412					const struct btf_type *t,
1413					u32 type_id,
1414					void *data)
1415{
1416	return btf_show_start_aggr_type(show, t, type_id, data);
1417}
1418
1419static void btf_show_end_struct_type(struct btf_show *show)
1420{
1421	btf_show_end_aggr_type(show, "}");
1422}
1423
1424__printf(2, 3) static void __btf_verifier_log(struct bpf_verifier_log *log,
1425					      const char *fmt, ...)
1426{
1427	va_list args;
1428
1429	va_start(args, fmt);
1430	bpf_verifier_vlog(log, fmt, args);
1431	va_end(args);
1432}
1433
1434__printf(2, 3) static void btf_verifier_log(struct btf_verifier_env *env,
1435					    const char *fmt, ...)
1436{
1437	struct bpf_verifier_log *log = &env->log;
1438	va_list args;
1439
1440	if (!bpf_verifier_log_needed(log))
1441		return;
1442
1443	va_start(args, fmt);
1444	bpf_verifier_vlog(log, fmt, args);
1445	va_end(args);
1446}
1447
1448__printf(4, 5) static void __btf_verifier_log_type(struct btf_verifier_env *env,
1449						   const struct btf_type *t,
1450						   bool log_details,
1451						   const char *fmt, ...)
1452{
1453	struct bpf_verifier_log *log = &env->log;
1454	struct btf *btf = env->btf;
1455	va_list args;
1456
1457	if (!bpf_verifier_log_needed(log))
1458		return;
1459
1460	if (log->level == BPF_LOG_KERNEL) {
1461		/* btf verifier prints all types it is processing via
1462		 * btf_verifier_log_type(..., fmt = NULL).
1463		 * Skip those prints for in-kernel BTF verification.
1464		 */
1465		if (!fmt)
1466			return;
1467
1468		/* Skip logging when loading module BTF with mismatches permitted */
1469		if (env->btf->base_btf && IS_ENABLED(CONFIG_MODULE_ALLOW_BTF_MISMATCH))
1470			return;
1471	}
1472
1473	__btf_verifier_log(log, "[%u] %s %s%s",
1474			   env->log_type_id,
1475			   btf_type_str(t),
1476			   __btf_name_by_offset(btf, t->name_off),
1477			   log_details ? " " : "");
1478
1479	if (log_details)
1480		btf_type_ops(t)->log_details(env, t);
1481
1482	if (fmt && *fmt) {
1483		__btf_verifier_log(log, " ");
1484		va_start(args, fmt);
1485		bpf_verifier_vlog(log, fmt, args);
1486		va_end(args);
1487	}
1488
1489	__btf_verifier_log(log, "\n");
1490}
1491
1492#define btf_verifier_log_type(env, t, ...) \
1493	__btf_verifier_log_type((env), (t), true, __VA_ARGS__)
1494#define btf_verifier_log_basic(env, t, ...) \
1495	__btf_verifier_log_type((env), (t), false, __VA_ARGS__)
1496
1497__printf(4, 5)
1498static void btf_verifier_log_member(struct btf_verifier_env *env,
1499				    const struct btf_type *struct_type,
1500				    const struct btf_member *member,
1501				    const char *fmt, ...)
1502{
1503	struct bpf_verifier_log *log = &env->log;
1504	struct btf *btf = env->btf;
1505	va_list args;
1506
1507	if (!bpf_verifier_log_needed(log))
1508		return;
1509
1510	if (log->level == BPF_LOG_KERNEL) {
1511		if (!fmt)
1512			return;
1513
1514		/* Skip logging when loading module BTF with mismatches permitted */
1515		if (env->btf->base_btf && IS_ENABLED(CONFIG_MODULE_ALLOW_BTF_MISMATCH))
1516			return;
1517	}
1518
1519	/* The CHECK_META phase already did a btf dump.
1520	 *
1521	 * If member is logged again, it must hit an error in
1522	 * parsing this member.  It is useful to print out which
1523	 * struct this member belongs to.
1524	 */
1525	if (env->phase != CHECK_META)
1526		btf_verifier_log_type(env, struct_type, NULL);
1527
1528	if (btf_type_kflag(struct_type))
1529		__btf_verifier_log(log,
1530				   "\t%s type_id=%u bitfield_size=%u bits_offset=%u",
1531				   __btf_name_by_offset(btf, member->name_off),
1532				   member->type,
1533				   BTF_MEMBER_BITFIELD_SIZE(member->offset),
1534				   BTF_MEMBER_BIT_OFFSET(member->offset));
1535	else
1536		__btf_verifier_log(log, "\t%s type_id=%u bits_offset=%u",
1537				   __btf_name_by_offset(btf, member->name_off),
1538				   member->type, member->offset);
1539
1540	if (fmt && *fmt) {
1541		__btf_verifier_log(log, " ");
1542		va_start(args, fmt);
1543		bpf_verifier_vlog(log, fmt, args);
1544		va_end(args);
1545	}
1546
1547	__btf_verifier_log(log, "\n");
1548}
1549
1550__printf(4, 5)
1551static void btf_verifier_log_vsi(struct btf_verifier_env *env,
1552				 const struct btf_type *datasec_type,
1553				 const struct btf_var_secinfo *vsi,
1554				 const char *fmt, ...)
1555{
1556	struct bpf_verifier_log *log = &env->log;
1557	va_list args;
1558
1559	if (!bpf_verifier_log_needed(log))
1560		return;
1561	if (log->level == BPF_LOG_KERNEL && !fmt)
1562		return;
1563	if (env->phase != CHECK_META)
1564		btf_verifier_log_type(env, datasec_type, NULL);
1565
1566	__btf_verifier_log(log, "\t type_id=%u offset=%u size=%u",
1567			   vsi->type, vsi->offset, vsi->size);
1568	if (fmt && *fmt) {
1569		__btf_verifier_log(log, " ");
1570		va_start(args, fmt);
1571		bpf_verifier_vlog(log, fmt, args);
1572		va_end(args);
1573	}
1574
1575	__btf_verifier_log(log, "\n");
1576}
1577
1578static void btf_verifier_log_hdr(struct btf_verifier_env *env,
1579				 u32 btf_data_size)
1580{
1581	struct bpf_verifier_log *log = &env->log;
1582	const struct btf *btf = env->btf;
1583	const struct btf_header *hdr;
1584
1585	if (!bpf_verifier_log_needed(log))
1586		return;
1587
1588	if (log->level == BPF_LOG_KERNEL)
1589		return;
1590	hdr = &btf->hdr;
1591	__btf_verifier_log(log, "magic: 0x%x\n", hdr->magic);
1592	__btf_verifier_log(log, "version: %u\n", hdr->version);
1593	__btf_verifier_log(log, "flags: 0x%x\n", hdr->flags);
1594	__btf_verifier_log(log, "hdr_len: %u\n", hdr->hdr_len);
1595	__btf_verifier_log(log, "type_off: %u\n", hdr->type_off);
1596	__btf_verifier_log(log, "type_len: %u\n", hdr->type_len);
1597	__btf_verifier_log(log, "str_off: %u\n", hdr->str_off);
1598	__btf_verifier_log(log, "str_len: %u\n", hdr->str_len);
1599	__btf_verifier_log(log, "btf_total_size: %u\n", btf_data_size);
1600}
1601
1602static int btf_add_type(struct btf_verifier_env *env, struct btf_type *t)
1603{
1604	struct btf *btf = env->btf;
1605
1606	if (btf->types_size == btf->nr_types) {
1607		/* Expand 'types' array */
1608
1609		struct btf_type **new_types;
1610		u32 expand_by, new_size;
1611
1612		if (btf->start_id + btf->types_size == BTF_MAX_TYPE) {
1613			btf_verifier_log(env, "Exceeded max num of types");
1614			return -E2BIG;
1615		}
1616
1617		expand_by = max_t(u32, btf->types_size >> 2, 16);
1618		new_size = min_t(u32, BTF_MAX_TYPE,
1619				 btf->types_size + expand_by);
1620
1621		new_types = kvcalloc(new_size, sizeof(*new_types),
1622				     GFP_KERNEL | __GFP_NOWARN);
1623		if (!new_types)
1624			return -ENOMEM;
1625
1626		if (btf->nr_types == 0) {
1627			if (!btf->base_btf) {
1628				/* lazily init VOID type */
1629				new_types[0] = &btf_void;
1630				btf->nr_types++;
1631			}
1632		} else {
1633			memcpy(new_types, btf->types,
1634			       sizeof(*btf->types) * btf->nr_types);
1635		}
1636
1637		kvfree(btf->types);
1638		btf->types = new_types;
1639		btf->types_size = new_size;
1640	}
1641
1642	btf->types[btf->nr_types++] = t;
1643
1644	return 0;
1645}
1646
1647static int btf_alloc_id(struct btf *btf)
1648{
1649	int id;
1650
1651	idr_preload(GFP_KERNEL);
1652	spin_lock_bh(&btf_idr_lock);
1653	id = idr_alloc_cyclic(&btf_idr, btf, 1, INT_MAX, GFP_ATOMIC);
1654	if (id > 0)
1655		btf->id = id;
1656	spin_unlock_bh(&btf_idr_lock);
1657	idr_preload_end();
1658
1659	if (WARN_ON_ONCE(!id))
1660		return -ENOSPC;
1661
1662	return id > 0 ? 0 : id;
1663}
1664
1665static void btf_free_id(struct btf *btf)
1666{
1667	unsigned long flags;
1668
1669	/*
1670	 * In map-in-map, calling map_delete_elem() on outer
1671	 * map will call bpf_map_put on the inner map.
1672	 * It will then eventually call btf_free_id()
1673	 * on the inner map.  Some of the map_delete_elem()
1674	 * implementation may have irq disabled, so
1675	 * we need to use the _irqsave() version instead
1676	 * of the _bh() version.
1677	 */
1678	spin_lock_irqsave(&btf_idr_lock, flags);
1679	if (btf->id) {
1680		idr_remove(&btf_idr, btf->id);
1681		/*
1682		 * Clear the id here to make this function idempotent, since it will get
1683		 * called a couple of times for module BTFs: on module unload, and then
1684		 * the final btf_put(). btf_alloc_id() starts IDs with 1, so we can use
1685		 * 0 as sentinel value.
1686		 */
1687		WRITE_ONCE(btf->id, 0);
1688	}
1689	spin_unlock_irqrestore(&btf_idr_lock, flags);
1690}
1691
1692static void btf_free_kfunc_set_tab(struct btf *btf)
1693{
1694	struct btf_kfunc_set_tab *tab = btf->kfunc_set_tab;
1695	int hook;
1696
1697	if (!tab)
1698		return;
1699	for (hook = 0; hook < ARRAY_SIZE(tab->sets); hook++)
1700		kfree(tab->sets[hook]);
1701	kfree(tab);
1702	btf->kfunc_set_tab = NULL;
1703}
1704
1705static void btf_free_dtor_kfunc_tab(struct btf *btf)
1706{
1707	struct btf_id_dtor_kfunc_tab *tab = btf->dtor_kfunc_tab;
1708
1709	if (!tab)
1710		return;
1711	kfree(tab);
1712	btf->dtor_kfunc_tab = NULL;
1713}
1714
1715static void btf_struct_metas_free(struct btf_struct_metas *tab)
1716{
1717	int i;
1718
1719	if (!tab)
1720		return;
1721	for (i = 0; i < tab->cnt; i++)
1722		btf_record_free(tab->types[i].record);
1723	kfree(tab);
1724}
1725
1726static void btf_free_struct_meta_tab(struct btf *btf)
1727{
1728	struct btf_struct_metas *tab = btf->struct_meta_tab;
1729
1730	btf_struct_metas_free(tab);
1731	btf->struct_meta_tab = NULL;
1732}
1733
1734static void btf_free_struct_ops_tab(struct btf *btf)
1735{
1736	struct btf_struct_ops_tab *tab = btf->struct_ops_tab;
1737	u32 i;
1738
1739	if (!tab)
1740		return;
1741
1742	for (i = 0; i < tab->cnt; i++)
1743		bpf_struct_ops_desc_release(&tab->ops[i]);
1744
1745	kfree(tab);
1746	btf->struct_ops_tab = NULL;
1747}
1748
1749static void btf_free(struct btf *btf)
1750{
1751	btf_free_struct_meta_tab(btf);
1752	btf_free_dtor_kfunc_tab(btf);
1753	btf_free_kfunc_set_tab(btf);
1754	btf_free_struct_ops_tab(btf);
1755	kvfree(btf->types);
1756	kvfree(btf->resolved_sizes);
1757	kvfree(btf->resolved_ids);
1758	/* vmlinux does not allocate btf->data, it simply points it at
1759	 * __start_BTF.
1760	 */
1761	if (!btf_is_vmlinux(btf))
1762		kvfree(btf->data);
1763	kvfree(btf->base_id_map);
1764	kfree(btf);
1765}
1766
1767static void btf_free_rcu(struct rcu_head *rcu)
1768{
1769	struct btf *btf = container_of(rcu, struct btf, rcu);
1770
1771	btf_free(btf);
1772}
1773
1774const char *btf_get_name(const struct btf *btf)
1775{
1776	return btf->name;
1777}
1778
1779void btf_get(struct btf *btf)
1780{
1781	refcount_inc(&btf->refcnt);
1782}
1783
1784void btf_put(struct btf *btf)
1785{
1786	if (btf && refcount_dec_and_test(&btf->refcnt)) {
1787		btf_free_id(btf);
1788		call_rcu(&btf->rcu, btf_free_rcu);
1789	}
1790}
1791
1792struct btf *btf_base_btf(const struct btf *btf)
1793{
1794	return btf->base_btf;
1795}
1796
1797const struct btf_header *btf_header(const struct btf *btf)
1798{
1799	return &btf->hdr;
1800}
1801
1802void btf_set_base_btf(struct btf *btf, const struct btf *base_btf)
1803{
1804	btf->base_btf = (struct btf *)base_btf;
1805	btf->start_id = btf_nr_types(base_btf);
1806	btf->start_str_off = base_btf->hdr.str_len;
1807}
1808
1809static int env_resolve_init(struct btf_verifier_env *env)
1810{
1811	struct btf *btf = env->btf;
1812	u32 nr_types = btf->nr_types;
1813	u32 *resolved_sizes = NULL;
1814	u32 *resolved_ids = NULL;
1815	u8 *visit_states = NULL;
1816
1817	resolved_sizes = kvcalloc(nr_types, sizeof(*resolved_sizes),
1818				  GFP_KERNEL | __GFP_NOWARN);
1819	if (!resolved_sizes)
1820		goto nomem;
1821
1822	resolved_ids = kvcalloc(nr_types, sizeof(*resolved_ids),
1823				GFP_KERNEL | __GFP_NOWARN);
1824	if (!resolved_ids)
1825		goto nomem;
1826
1827	visit_states = kvcalloc(nr_types, sizeof(*visit_states),
1828				GFP_KERNEL | __GFP_NOWARN);
1829	if (!visit_states)
1830		goto nomem;
1831
1832	btf->resolved_sizes = resolved_sizes;
1833	btf->resolved_ids = resolved_ids;
1834	env->visit_states = visit_states;
1835
1836	return 0;
1837
1838nomem:
1839	kvfree(resolved_sizes);
1840	kvfree(resolved_ids);
1841	kvfree(visit_states);
1842	return -ENOMEM;
1843}
1844
1845static void btf_verifier_env_free(struct btf_verifier_env *env)
1846{
1847	kvfree(env->visit_states);
1848	kfree(env);
1849}
1850
1851static bool env_type_is_resolve_sink(const struct btf_verifier_env *env,
1852				     const struct btf_type *next_type)
1853{
1854	switch (env->resolve_mode) {
1855	case RESOLVE_TBD:
1856		/* int, enum or void is a sink */
1857		return !btf_type_needs_resolve(next_type);
1858	case RESOLVE_PTR:
1859		/* int, enum, void, struct, array, func or func_proto is a sink
1860		 * for ptr
1861		 */
1862		return !btf_type_is_modifier(next_type) &&
1863			!btf_type_is_ptr(next_type);
1864	case RESOLVE_STRUCT_OR_ARRAY:
1865		/* int, enum, void, ptr, func or func_proto is a sink
1866		 * for struct and array
1867		 */
1868		return !btf_type_is_modifier(next_type) &&
1869			!btf_type_is_array(next_type) &&
1870			!btf_type_is_struct(next_type);
1871	default:
1872		BUG();
1873	}
1874}
1875
1876static bool env_type_is_resolved(const struct btf_verifier_env *env,
1877				 u32 type_id)
1878{
1879	/* base BTF types should be resolved by now */
1880	if (type_id < env->btf->start_id)
1881		return true;
1882
1883	return env->visit_states[type_id - env->btf->start_id] == RESOLVED;
1884}
1885
1886static int env_stack_push(struct btf_verifier_env *env,
1887			  const struct btf_type *t, u32 type_id)
1888{
1889	const struct btf *btf = env->btf;
1890	struct resolve_vertex *v;
1891
1892	if (env->top_stack == MAX_RESOLVE_DEPTH)
1893		return -E2BIG;
1894
1895	if (type_id < btf->start_id
1896	    || env->visit_states[type_id - btf->start_id] != NOT_VISITED)
1897		return -EEXIST;
1898
1899	env->visit_states[type_id - btf->start_id] = VISITED;
1900
1901	v = &env->stack[env->top_stack++];
1902	v->t = t;
1903	v->type_id = type_id;
1904	v->next_member = 0;
1905
1906	if (env->resolve_mode == RESOLVE_TBD) {
1907		if (btf_type_is_ptr(t))
1908			env->resolve_mode = RESOLVE_PTR;
1909		else if (btf_type_is_struct(t) || btf_type_is_array(t))
1910			env->resolve_mode = RESOLVE_STRUCT_OR_ARRAY;
1911	}
1912
1913	return 0;
1914}
1915
1916static void env_stack_set_next_member(struct btf_verifier_env *env,
1917				      u16 next_member)
1918{
1919	env->stack[env->top_stack - 1].next_member = next_member;
1920}
1921
1922static void env_stack_pop_resolved(struct btf_verifier_env *env,
1923				   u32 resolved_type_id,
1924				   u32 resolved_size)
1925{
1926	u32 type_id = env->stack[--(env->top_stack)].type_id;
1927	struct btf *btf = env->btf;
1928
1929	type_id -= btf->start_id; /* adjust to local type id */
1930	btf->resolved_sizes[type_id] = resolved_size;
1931	btf->resolved_ids[type_id] = resolved_type_id;
1932	env->visit_states[type_id] = RESOLVED;
1933}
1934
1935static const struct resolve_vertex *env_stack_peak(struct btf_verifier_env *env)
1936{
1937	return env->top_stack ? &env->stack[env->top_stack - 1] : NULL;
1938}
1939
1940/* Resolve the size of a passed-in "type"
1941 *
1942 * type: is an array (e.g. u32 array[x][y])
1943 * return type: type "u32[x][y]", i.e. BTF_KIND_ARRAY,
1944 * *type_size: (x * y * sizeof(u32)).  Hence, *type_size always
1945 *             corresponds to the return type.
1946 * *elem_type: u32
1947 * *elem_id: id of u32
1948 * *total_nelems: (x * y).  Hence, individual elem size is
1949 *                (*type_size / *total_nelems)
1950 * *type_id: id of type if it's changed within the function, 0 if not
1951 *
1952 * type: is not an array (e.g. const struct X)
1953 * return type: type "struct X"
1954 * *type_size: sizeof(struct X)
1955 * *elem_type: same as return type ("struct X")
1956 * *elem_id: 0
1957 * *total_nelems: 1
1958 * *type_id: id of type if it's changed within the function, 0 if not
1959 */
1960static const struct btf_type *
1961__btf_resolve_size(const struct btf *btf, const struct btf_type *type,
1962		   u32 *type_size, const struct btf_type **elem_type,
1963		   u32 *elem_id, u32 *total_nelems, u32 *type_id)
1964{
1965	const struct btf_type *array_type = NULL;
1966	const struct btf_array *array = NULL;
1967	u32 i, size, nelems = 1, id = 0;
1968
1969	for (i = 0; i < MAX_RESOLVE_DEPTH; i++) {
1970		switch (BTF_INFO_KIND(type->info)) {
1971		/* type->size can be used */
1972		case BTF_KIND_INT:
1973		case BTF_KIND_STRUCT:
1974		case BTF_KIND_UNION:
1975		case BTF_KIND_ENUM:
1976		case BTF_KIND_FLOAT:
1977		case BTF_KIND_ENUM64:
1978			size = type->size;
1979			goto resolved;
1980
1981		case BTF_KIND_PTR:
1982			size = sizeof(void *);
1983			goto resolved;
1984
1985		/* Modifiers */
1986		case BTF_KIND_TYPEDEF:
1987		case BTF_KIND_VOLATILE:
1988		case BTF_KIND_CONST:
1989		case BTF_KIND_RESTRICT:
1990		case BTF_KIND_TYPE_TAG:
1991			id = type->type;
1992			type = btf_type_by_id(btf, type->type);
1993			break;
1994
1995		case BTF_KIND_ARRAY:
1996			if (!array_type)
1997				array_type = type;
1998			array = btf_type_array(type);
1999			if (nelems && array->nelems > U32_MAX / nelems)
2000				return ERR_PTR(-EINVAL);
2001			nelems *= array->nelems;
2002			type = btf_type_by_id(btf, array->type);
2003			break;
2004
2005		/* type without size */
2006		default:
2007			return ERR_PTR(-EINVAL);
2008		}
2009	}
2010
2011	return ERR_PTR(-EINVAL);
2012
2013resolved:
2014	if (nelems && size > U32_MAX / nelems)
2015		return ERR_PTR(-EINVAL);
2016
2017	*type_size = nelems * size;
2018	if (total_nelems)
2019		*total_nelems = nelems;
2020	if (elem_type)
2021		*elem_type = type;
2022	if (elem_id)
2023		*elem_id = array ? array->type : 0;
2024	if (type_id && id)
2025		*type_id = id;
2026
2027	return array_type ? : type;
2028}
2029
2030const struct btf_type *
2031btf_resolve_size(const struct btf *btf, const struct btf_type *type,
2032		 u32 *type_size)
2033{
2034	return __btf_resolve_size(btf, type, type_size, NULL, NULL, NULL, NULL);
2035}
2036
2037static u32 btf_resolved_type_id(const struct btf *btf, u32 type_id)
2038{
2039	while (type_id < btf->start_id)
2040		btf = btf->base_btf;
2041
2042	return btf->resolved_ids[type_id - btf->start_id];
2043}
2044
2045/* The input param "type_id" must point to a needs_resolve type */
2046static const struct btf_type *btf_type_id_resolve(const struct btf *btf,
2047						  u32 *type_id)
2048{
2049	*type_id = btf_resolved_type_id(btf, *type_id);
2050	return btf_type_by_id(btf, *type_id);
2051}
2052
2053static u32 btf_resolved_type_size(const struct btf *btf, u32 type_id)
2054{
2055	while (type_id < btf->start_id)
2056		btf = btf->base_btf;
2057
2058	return btf->resolved_sizes[type_id - btf->start_id];
2059}
2060
2061const struct btf_type *btf_type_id_size(const struct btf *btf,
2062					u32 *type_id, u32 *ret_size)
2063{
2064	const struct btf_type *size_type;
2065	u32 size_type_id = *type_id;
2066	u32 size = 0;
2067
2068	size_type = btf_type_by_id(btf, size_type_id);
2069	if (btf_type_nosize_or_null(size_type))
2070		return NULL;
2071
2072	if (btf_type_has_size(size_type)) {
2073		size = size_type->size;
2074	} else if (btf_type_is_array(size_type)) {
2075		size = btf_resolved_type_size(btf, size_type_id);
2076	} else if (btf_type_is_ptr(size_type)) {
2077		size = sizeof(void *);
2078	} else {
2079		if (WARN_ON_ONCE(!btf_type_is_modifier(size_type) &&
2080				 !btf_type_is_var(size_type)))
2081			return NULL;
2082
2083		size_type_id = btf_resolved_type_id(btf, size_type_id);
2084		size_type = btf_type_by_id(btf, size_type_id);
2085		if (btf_type_nosize_or_null(size_type))
2086			return NULL;
2087		else if (btf_type_has_size(size_type))
2088			size = size_type->size;
2089		else if (btf_type_is_array(size_type))
2090			size = btf_resolved_type_size(btf, size_type_id);
2091		else if (btf_type_is_ptr(size_type))
2092			size = sizeof(void *);
2093		else
2094			return NULL;
2095	}
2096
2097	*type_id = size_type_id;
2098	if (ret_size)
2099		*ret_size = size;
2100
2101	return size_type;
2102}
2103
2104static int btf_df_check_member(struct btf_verifier_env *env,
2105			       const struct btf_type *struct_type,
2106			       const struct btf_member *member,
2107			       const struct btf_type *member_type)
2108{
2109	btf_verifier_log_basic(env, struct_type,
2110			       "Unsupported check_member");
2111	return -EINVAL;
2112}
2113
2114static int btf_df_check_kflag_member(struct btf_verifier_env *env,
2115				     const struct btf_type *struct_type,
2116				     const struct btf_member *member,
2117				     const struct btf_type *member_type)
2118{
2119	btf_verifier_log_basic(env, struct_type,
2120			       "Unsupported check_kflag_member");
2121	return -EINVAL;
2122}
2123
2124/* Used for ptr, array struct/union and float type members.
2125 * int, enum and modifier types have their specific callback functions.
2126 */
2127static int btf_generic_check_kflag_member(struct btf_verifier_env *env,
2128					  const struct btf_type *struct_type,
2129					  const struct btf_member *member,
2130					  const struct btf_type *member_type)
2131{
2132	if (BTF_MEMBER_BITFIELD_SIZE(member->offset)) {
2133		btf_verifier_log_member(env, struct_type, member,
2134					"Invalid member bitfield_size");
2135		return -EINVAL;
2136	}
2137
2138	/* bitfield size is 0, so member->offset represents bit offset only.
2139	 * It is safe to call non kflag check_member variants.
2140	 */
2141	return btf_type_ops(member_type)->check_member(env, struct_type,
2142						       member,
2143						       member_type);
2144}
2145
2146static int btf_df_resolve(struct btf_verifier_env *env,
2147			  const struct resolve_vertex *v)
2148{
2149	btf_verifier_log_basic(env, v->t, "Unsupported resolve");
2150	return -EINVAL;
2151}
2152
2153static void btf_df_show(const struct btf *btf, const struct btf_type *t,
2154			u32 type_id, void *data, u8 bits_offsets,
2155			struct btf_show *show)
2156{
2157	btf_show(show, "<unsupported kind:%u>", BTF_INFO_KIND(t->info));
2158}
2159
2160static int btf_int_check_member(struct btf_verifier_env *env,
2161				const struct btf_type *struct_type,
2162				const struct btf_member *member,
2163				const struct btf_type *member_type)
2164{
2165	u32 int_data = btf_type_int(member_type);
2166	u32 struct_bits_off = member->offset;
2167	u32 struct_size = struct_type->size;
2168	u32 nr_copy_bits;
2169	u32 bytes_offset;
2170
2171	if (U32_MAX - struct_bits_off < BTF_INT_OFFSET(int_data)) {
2172		btf_verifier_log_member(env, struct_type, member,
2173					"bits_offset exceeds U32_MAX");
2174		return -EINVAL;
2175	}
2176
2177	struct_bits_off += BTF_INT_OFFSET(int_data);
2178	bytes_offset = BITS_ROUNDDOWN_BYTES(struct_bits_off);
2179	nr_copy_bits = BTF_INT_BITS(int_data) +
2180		BITS_PER_BYTE_MASKED(struct_bits_off);
2181
2182	if (nr_copy_bits > BITS_PER_U128) {
2183		btf_verifier_log_member(env, struct_type, member,
2184					"nr_copy_bits exceeds 128");
2185		return -EINVAL;
2186	}
2187
2188	if (struct_size < bytes_offset ||
2189	    struct_size - bytes_offset < BITS_ROUNDUP_BYTES(nr_copy_bits)) {
2190		btf_verifier_log_member(env, struct_type, member,
2191					"Member exceeds struct_size");
2192		return -EINVAL;
2193	}
2194
2195	return 0;
2196}
2197
2198static int btf_int_check_kflag_member(struct btf_verifier_env *env,
2199				      const struct btf_type *struct_type,
2200				      const struct btf_member *member,
2201				      const struct btf_type *member_type)
2202{
2203	u32 struct_bits_off, nr_bits, nr_int_data_bits, bytes_offset;
2204	u32 int_data = btf_type_int(member_type);
2205	u32 struct_size = struct_type->size;
2206	u32 nr_copy_bits;
2207
2208	/* a regular int type is required for the kflag int member */
2209	if (!btf_type_int_is_regular(member_type)) {
2210		btf_verifier_log_member(env, struct_type, member,
2211					"Invalid member base type");
2212		return -EINVAL;
2213	}
2214
2215	/* check sanity of bitfield size */
2216	nr_bits = BTF_MEMBER_BITFIELD_SIZE(member->offset);
2217	struct_bits_off = BTF_MEMBER_BIT_OFFSET(member->offset);
2218	nr_int_data_bits = BTF_INT_BITS(int_data);
2219	if (!nr_bits) {
2220		/* Not a bitfield member, member offset must be at byte
2221		 * boundary.
2222		 */
2223		if (BITS_PER_BYTE_MASKED(struct_bits_off)) {
2224			btf_verifier_log_member(env, struct_type, member,
2225						"Invalid member offset");
2226			return -EINVAL;
2227		}
2228
2229		nr_bits = nr_int_data_bits;
2230	} else if (nr_bits > nr_int_data_bits) {
2231		btf_verifier_log_member(env, struct_type, member,
2232					"Invalid member bitfield_size");
2233		return -EINVAL;
2234	}
2235
2236	bytes_offset = BITS_ROUNDDOWN_BYTES(struct_bits_off);
2237	nr_copy_bits = nr_bits + BITS_PER_BYTE_MASKED(struct_bits_off);
2238	if (nr_copy_bits > BITS_PER_U128) {
2239		btf_verifier_log_member(env, struct_type, member,
2240					"nr_copy_bits exceeds 128");
2241		return -EINVAL;
2242	}
2243
2244	if (struct_size < bytes_offset ||
2245	    struct_size - bytes_offset < BITS_ROUNDUP_BYTES(nr_copy_bits)) {
2246		btf_verifier_log_member(env, struct_type, member,
2247					"Member exceeds struct_size");
2248		return -EINVAL;
2249	}
2250
2251	return 0;
2252}
2253
2254static s32 btf_int_check_meta(struct btf_verifier_env *env,
2255			      const struct btf_type *t,
2256			      u32 meta_left)
2257{
2258	u32 int_data, nr_bits, meta_needed = sizeof(int_data);
2259	u16 encoding;
2260
2261	if (meta_left < meta_needed) {
2262		btf_verifier_log_basic(env, t,
2263				       "meta_left:%u meta_needed:%u",
2264				       meta_left, meta_needed);
2265		return -EINVAL;
2266	}
2267
2268	if (btf_type_vlen(t)) {
2269		btf_verifier_log_type(env, t, "vlen != 0");
2270		return -EINVAL;
2271	}
2272
2273	if (btf_type_kflag(t)) {
2274		btf_verifier_log_type(env, t, "Invalid btf_info kind_flag");
2275		return -EINVAL;
2276	}
2277
2278	int_data = btf_type_int(t);
2279	if (int_data & ~BTF_INT_MASK) {
2280		btf_verifier_log_basic(env, t, "Invalid int_data:%x",
2281				       int_data);
2282		return -EINVAL;
2283	}
2284
2285	nr_bits = BTF_INT_BITS(int_data) + BTF_INT_OFFSET(int_data);
2286
2287	if (nr_bits > BITS_PER_U128) {
2288		btf_verifier_log_type(env, t, "nr_bits exceeds %zu",
2289				      BITS_PER_U128);
2290		return -EINVAL;
2291	}
2292
2293	if (BITS_ROUNDUP_BYTES(nr_bits) > t->size) {
2294		btf_verifier_log_type(env, t, "nr_bits exceeds type_size");
2295		return -EINVAL;
2296	}
2297
2298	/*
2299	 * Only one of the encoding bits is allowed and it
2300	 * should be sufficient for the pretty print purpose (i.e. decoding).
2301	 * Multiple bits can be allowed later if it is found
2302	 * to be insufficient.
2303	 */
2304	encoding = BTF_INT_ENCODING(int_data);
2305	if (encoding &&
2306	    encoding != BTF_INT_SIGNED &&
2307	    encoding != BTF_INT_CHAR &&
2308	    encoding != BTF_INT_BOOL) {
2309		btf_verifier_log_type(env, t, "Unsupported encoding");
2310		return -ENOTSUPP;
2311	}
2312
2313	btf_verifier_log_type(env, t, NULL);
2314
2315	return meta_needed;
2316}
2317
2318static void btf_int_log(struct btf_verifier_env *env,
2319			const struct btf_type *t)
2320{
2321	int int_data = btf_type_int(t);
2322
2323	btf_verifier_log(env,
2324			 "size=%u bits_offset=%u nr_bits=%u encoding=%s",
2325			 t->size, BTF_INT_OFFSET(int_data),
2326			 BTF_INT_BITS(int_data),
2327			 btf_int_encoding_str(BTF_INT_ENCODING(int_data)));
2328}
2329
2330static void btf_int128_print(struct btf_show *show, void *data)
2331{
2332	/* data points to a __int128 number.
2333	 * Suppose
2334	 *     int128_num = *(__int128 *)data;
2335	 * The below formulas shows what upper_num and lower_num represents:
2336	 *     upper_num = int128_num >> 64;
2337	 *     lower_num = int128_num & 0xffffffffFFFFFFFFULL;
2338	 */
2339	u64 upper_num, lower_num;
2340
2341#ifdef __BIG_ENDIAN_BITFIELD
2342	upper_num = *(u64 *)data;
2343	lower_num = *(u64 *)(data + 8);
2344#else
2345	upper_num = *(u64 *)(data + 8);
2346	lower_num = *(u64 *)data;
2347#endif
2348	if (upper_num == 0)
2349		btf_show_type_value(show, "0x%llx", lower_num);
2350	else
2351		btf_show_type_values(show, "0x%llx%016llx", upper_num,
2352				     lower_num);
2353}
2354
2355static void btf_int128_shift(u64 *print_num, u16 left_shift_bits,
2356			     u16 right_shift_bits)
2357{
2358	u64 upper_num, lower_num;
2359
2360#ifdef __BIG_ENDIAN_BITFIELD
2361	upper_num = print_num[0];
2362	lower_num = print_num[1];
2363#else
2364	upper_num = print_num[1];
2365	lower_num = print_num[0];
2366#endif
2367
2368	/* shake out un-needed bits by shift/or operations */
2369	if (left_shift_bits >= 64) {
2370		upper_num = lower_num << (left_shift_bits - 64);
2371		lower_num = 0;
2372	} else {
2373		upper_num = (upper_num << left_shift_bits) |
2374			    (lower_num >> (64 - left_shift_bits));
2375		lower_num = lower_num << left_shift_bits;
2376	}
2377
2378	if (right_shift_bits >= 64) {
2379		lower_num = upper_num >> (right_shift_bits - 64);
2380		upper_num = 0;
2381	} else {
2382		lower_num = (lower_num >> right_shift_bits) |
2383			    (upper_num << (64 - right_shift_bits));
2384		upper_num = upper_num >> right_shift_bits;
2385	}
2386
2387#ifdef __BIG_ENDIAN_BITFIELD
2388	print_num[0] = upper_num;
2389	print_num[1] = lower_num;
2390#else
2391	print_num[0] = lower_num;
2392	print_num[1] = upper_num;
2393#endif
2394}
2395
2396static void btf_bitfield_show(void *data, u8 bits_offset,
2397			      u8 nr_bits, struct btf_show *show)
2398{
2399	u16 left_shift_bits, right_shift_bits;
2400	u8 nr_copy_bytes;
2401	u8 nr_copy_bits;
2402	u64 print_num[2] = {};
2403
2404	nr_copy_bits = nr_bits + bits_offset;
2405	nr_copy_bytes = BITS_ROUNDUP_BYTES(nr_copy_bits);
2406
2407	memcpy(print_num, data, nr_copy_bytes);
2408
2409#ifdef __BIG_ENDIAN_BITFIELD
2410	left_shift_bits = bits_offset;
2411#else
2412	left_shift_bits = BITS_PER_U128 - nr_copy_bits;
2413#endif
2414	right_shift_bits = BITS_PER_U128 - nr_bits;
2415
2416	btf_int128_shift(print_num, left_shift_bits, right_shift_bits);
2417	btf_int128_print(show, print_num);
2418}
2419
2420
2421static void btf_int_bits_show(const struct btf *btf,
2422			      const struct btf_type *t,
2423			      void *data, u8 bits_offset,
2424			      struct btf_show *show)
2425{
2426	u32 int_data = btf_type_int(t);
2427	u8 nr_bits = BTF_INT_BITS(int_data);
2428	u8 total_bits_offset;
2429
2430	/*
2431	 * bits_offset is at most 7.
2432	 * BTF_INT_OFFSET() cannot exceed 128 bits.
2433	 */
2434	total_bits_offset = bits_offset + BTF_INT_OFFSET(int_data);
2435	data += BITS_ROUNDDOWN_BYTES(total_bits_offset);
2436	bits_offset = BITS_PER_BYTE_MASKED(total_bits_offset);
2437	btf_bitfield_show(data, bits_offset, nr_bits, show);
2438}
2439
2440static void btf_int_show(const struct btf *btf, const struct btf_type *t,
2441			 u32 type_id, void *data, u8 bits_offset,
2442			 struct btf_show *show)
2443{
2444	u32 int_data = btf_type_int(t);
2445	u8 encoding = BTF_INT_ENCODING(int_data);
2446	bool sign = encoding & BTF_INT_SIGNED;
2447	u8 nr_bits = BTF_INT_BITS(int_data);
2448	void *safe_data;
2449
2450	safe_data = btf_show_start_type(show, t, type_id, data);
2451	if (!safe_data)
2452		return;
2453
2454	if (bits_offset || BTF_INT_OFFSET(int_data) ||
2455	    BITS_PER_BYTE_MASKED(nr_bits)) {
2456		btf_int_bits_show(btf, t, safe_data, bits_offset, show);
2457		goto out;
2458	}
2459
2460	switch (nr_bits) {
2461	case 128:
2462		btf_int128_print(show, safe_data);
2463		break;
2464	case 64:
2465		if (sign)
2466			btf_show_type_value(show, "%lld", *(s64 *)safe_data);
2467		else
2468			btf_show_type_value(show, "%llu", *(u64 *)safe_data);
2469		break;
2470	case 32:
2471		if (sign)
2472			btf_show_type_value(show, "%d", *(s32 *)safe_data);
2473		else
2474			btf_show_type_value(show, "%u", *(u32 *)safe_data);
2475		break;
2476	case 16:
2477		if (sign)
2478			btf_show_type_value(show, "%d", *(s16 *)safe_data);
2479		else
2480			btf_show_type_value(show, "%u", *(u16 *)safe_data);
2481		break;
2482	case 8:
2483		if (show->state.array_encoding == BTF_INT_CHAR) {
2484			/* check for null terminator */
2485			if (show->state.array_terminated)
2486				break;
2487			if (*(char *)data == '\0') {
2488				show->state.array_terminated = 1;
2489				break;
2490			}
2491			if (isprint(*(char *)data)) {
2492				btf_show_type_value(show, "'%c'",
2493						    *(char *)safe_data);
2494				break;
2495			}
2496		}
2497		if (sign)
2498			btf_show_type_value(show, "%d", *(s8 *)safe_data);
2499		else
2500			btf_show_type_value(show, "%u", *(u8 *)safe_data);
2501		break;
2502	default:
2503		btf_int_bits_show(btf, t, safe_data, bits_offset, show);
2504		break;
2505	}
2506out:
2507	btf_show_end_type(show);
2508}
2509
2510static const struct btf_kind_operations int_ops = {
2511	.check_meta = btf_int_check_meta,
2512	.resolve = btf_df_resolve,
2513	.check_member = btf_int_check_member,
2514	.check_kflag_member = btf_int_check_kflag_member,
2515	.log_details = btf_int_log,
2516	.show = btf_int_show,
2517};
2518
2519static int btf_modifier_check_member(struct btf_verifier_env *env,
2520				     const struct btf_type *struct_type,
2521				     const struct btf_member *member,
2522				     const struct btf_type *member_type)
2523{
2524	const struct btf_type *resolved_type;
2525	u32 resolved_type_id = member->type;
2526	struct btf_member resolved_member;
2527	struct btf *btf = env->btf;
2528
2529	resolved_type = btf_type_id_size(btf, &resolved_type_id, NULL);
2530	if (!resolved_type) {
2531		btf_verifier_log_member(env, struct_type, member,
2532					"Invalid member");
2533		return -EINVAL;
2534	}
2535
2536	resolved_member = *member;
2537	resolved_member.type = resolved_type_id;
2538
2539	return btf_type_ops(resolved_type)->check_member(env, struct_type,
2540							 &resolved_member,
2541							 resolved_type);
2542}
2543
2544static int btf_modifier_check_kflag_member(struct btf_verifier_env *env,
2545					   const struct btf_type *struct_type,
2546					   const struct btf_member *member,
2547					   const struct btf_type *member_type)
2548{
2549	const struct btf_type *resolved_type;
2550	u32 resolved_type_id = member->type;
2551	struct btf_member resolved_member;
2552	struct btf *btf = env->btf;
2553
2554	resolved_type = btf_type_id_size(btf, &resolved_type_id, NULL);
2555	if (!resolved_type) {
2556		btf_verifier_log_member(env, struct_type, member,
2557					"Invalid member");
2558		return -EINVAL;
2559	}
2560
2561	resolved_member = *member;
2562	resolved_member.type = resolved_type_id;
2563
2564	return btf_type_ops(resolved_type)->check_kflag_member(env, struct_type,
2565							       &resolved_member,
2566							       resolved_type);
2567}
2568
2569static int btf_ptr_check_member(struct btf_verifier_env *env,
2570				const struct btf_type *struct_type,
2571				const struct btf_member *member,
2572				const struct btf_type *member_type)
2573{
2574	u32 struct_size, struct_bits_off, bytes_offset;
2575
2576	struct_size = struct_type->size;
2577	struct_bits_off = member->offset;
2578	bytes_offset = BITS_ROUNDDOWN_BYTES(struct_bits_off);
2579
2580	if (BITS_PER_BYTE_MASKED(struct_bits_off)) {
2581		btf_verifier_log_member(env, struct_type, member,
2582					"Member is not byte aligned");
2583		return -EINVAL;
2584	}
2585
2586	if (struct_size - bytes_offset < sizeof(void *)) {
2587		btf_verifier_log_member(env, struct_type, member,
2588					"Member exceeds struct_size");
2589		return -EINVAL;
2590	}
2591
2592	return 0;
2593}
2594
2595static int btf_ref_type_check_meta(struct btf_verifier_env *env,
2596				   const struct btf_type *t,
2597				   u32 meta_left)
2598{
2599	const char *value;
2600
2601	if (btf_type_vlen(t)) {
2602		btf_verifier_log_type(env, t, "vlen != 0");
2603		return -EINVAL;
2604	}
2605
2606	if (btf_type_kflag(t) && !btf_type_is_type_tag(t)) {
2607		btf_verifier_log_type(env, t, "Invalid btf_info kind_flag");
2608		return -EINVAL;
2609	}
2610
2611	if (!BTF_TYPE_ID_VALID(t->type)) {
2612		btf_verifier_log_type(env, t, "Invalid type_id");
2613		return -EINVAL;
2614	}
2615
2616	/* typedef/type_tag type must have a valid name, and other ref types,
2617	 * volatile, const, restrict, should have a null name.
2618	 */
2619	if (BTF_INFO_KIND(t->info) == BTF_KIND_TYPEDEF) {
2620		if (!t->name_off ||
2621		    !btf_name_valid_identifier(env->btf, t->name_off)) {
2622			btf_verifier_log_type(env, t, "Invalid name");
2623			return -EINVAL;
2624		}
2625	} else if (BTF_INFO_KIND(t->info) == BTF_KIND_TYPE_TAG) {
2626		value = btf_name_by_offset(env->btf, t->name_off);
2627		if (!value || !value[0]) {
2628			btf_verifier_log_type(env, t, "Invalid name");
2629			return -EINVAL;
2630		}
2631	} else {
2632		if (t->name_off) {
2633			btf_verifier_log_type(env, t, "Invalid name");
2634			return -EINVAL;
2635		}
2636	}
2637
2638	btf_verifier_log_type(env, t, NULL);
2639
2640	return 0;
2641}
2642
2643static int btf_modifier_resolve(struct btf_verifier_env *env,
2644				const struct resolve_vertex *v)
2645{
2646	const struct btf_type *t = v->t;
2647	const struct btf_type *next_type;
2648	u32 next_type_id = t->type;
2649	struct btf *btf = env->btf;
2650
2651	next_type = btf_type_by_id(btf, next_type_id);
2652	if (!next_type || btf_type_is_resolve_source_only(next_type)) {
2653		btf_verifier_log_type(env, v->t, "Invalid type_id");
2654		return -EINVAL;
2655	}
2656
2657	if (!env_type_is_resolve_sink(env, next_type) &&
2658	    !env_type_is_resolved(env, next_type_id))
2659		return env_stack_push(env, next_type, next_type_id);
2660
2661	/* Figure out the resolved next_type_id with size.
2662	 * They will be stored in the current modifier's
2663	 * resolved_ids and resolved_sizes such that it can
2664	 * save us a few type-following when we use it later (e.g. in
2665	 * pretty print).
2666	 */
2667	if (!btf_type_id_size(btf, &next_type_id, NULL)) {
2668		if (env_type_is_resolved(env, next_type_id))
2669			next_type = btf_type_id_resolve(btf, &next_type_id);
2670
2671		/* "typedef void new_void", "const void"...etc */
2672		if (!btf_type_is_void(next_type) &&
2673		    !btf_type_is_fwd(next_type) &&
2674		    !btf_type_is_func_proto(next_type)) {
2675			btf_verifier_log_type(env, v->t, "Invalid type_id");
2676			return -EINVAL;
2677		}
2678	}
2679
2680	env_stack_pop_resolved(env, next_type_id, 0);
2681
2682	return 0;
2683}
2684
2685static int btf_var_resolve(struct btf_verifier_env *env,
2686			   const struct resolve_vertex *v)
2687{
2688	const struct btf_type *next_type;
2689	const struct btf_type *t = v->t;
2690	u32 next_type_id = t->type;
2691	struct btf *btf = env->btf;
2692
2693	next_type = btf_type_by_id(btf, next_type_id);
2694	if (!next_type || btf_type_is_resolve_source_only(next_type)) {
2695		btf_verifier_log_type(env, v->t, "Invalid type_id");
2696		return -EINVAL;
2697	}
2698
2699	if (!env_type_is_resolve_sink(env, next_type) &&
2700	    !env_type_is_resolved(env, next_type_id))
2701		return env_stack_push(env, next_type, next_type_id);
2702
2703	if (btf_type_is_modifier(next_type)) {
2704		const struct btf_type *resolved_type;
2705		u32 resolved_type_id;
2706
2707		resolved_type_id = next_type_id;
2708		resolved_type = btf_type_id_resolve(btf, &resolved_type_id);
2709
2710		if (btf_type_is_ptr(resolved_type) &&
2711		    !env_type_is_resolve_sink(env, resolved_type) &&
2712		    !env_type_is_resolved(env, resolved_type_id))
2713			return env_stack_push(env, resolved_type,
2714					      resolved_type_id);
2715	}
2716
2717	/* We must resolve to something concrete at this point, no
2718	 * forward types or similar that would resolve to size of
2719	 * zero is allowed.
2720	 */
2721	if (!btf_type_id_size(btf, &next_type_id, NULL)) {
2722		btf_verifier_log_type(env, v->t, "Invalid type_id");
2723		return -EINVAL;
2724	}
2725
2726	env_stack_pop_resolved(env, next_type_id, 0);
2727
2728	return 0;
2729}
2730
2731static int btf_ptr_resolve(struct btf_verifier_env *env,
2732			   const struct resolve_vertex *v)
2733{
2734	const struct btf_type *next_type;
2735	const struct btf_type *t = v->t;
2736	u32 next_type_id = t->type;
2737	struct btf *btf = env->btf;
2738
2739	next_type = btf_type_by_id(btf, next_type_id);
2740	if (!next_type || btf_type_is_resolve_source_only(next_type)) {
2741		btf_verifier_log_type(env, v->t, "Invalid type_id");
2742		return -EINVAL;
2743	}
2744
2745	if (!env_type_is_resolve_sink(env, next_type) &&
2746	    !env_type_is_resolved(env, next_type_id))
2747		return env_stack_push(env, next_type, next_type_id);
2748
2749	/* If the modifier was RESOLVED during RESOLVE_STRUCT_OR_ARRAY,
2750	 * the modifier may have stopped resolving when it was resolved
2751	 * to a ptr (last-resolved-ptr).
2752	 *
2753	 * We now need to continue from the last-resolved-ptr to
2754	 * ensure the last-resolved-ptr will not referring back to
2755	 * the current ptr (t).
2756	 */
2757	if (btf_type_is_modifier(next_type)) {
2758		const struct btf_type *resolved_type;
2759		u32 resolved_type_id;
2760
2761		resolved_type_id = next_type_id;
2762		resolved_type = btf_type_id_resolve(btf, &resolved_type_id);
2763
2764		if (btf_type_is_ptr(resolved_type) &&
2765		    !env_type_is_resolve_sink(env, resolved_type) &&
2766		    !env_type_is_resolved(env, resolved_type_id))
2767			return env_stack_push(env, resolved_type,
2768					      resolved_type_id);
2769	}
2770
2771	if (!btf_type_id_size(btf, &next_type_id, NULL)) {
2772		if (env_type_is_resolved(env, next_type_id))
2773			next_type = btf_type_id_resolve(btf, &next_type_id);
2774
2775		if (!btf_type_is_void(next_type) &&
2776		    !btf_type_is_fwd(next_type) &&
2777		    !btf_type_is_func_proto(next_type)) {
2778			btf_verifier_log_type(env, v->t, "Invalid type_id");
2779			return -EINVAL;
2780		}
2781	}
2782
2783	env_stack_pop_resolved(env, next_type_id, 0);
2784
2785	return 0;
2786}
2787
2788static void btf_modifier_show(const struct btf *btf,
2789			      const struct btf_type *t,
2790			      u32 type_id, void *data,
2791			      u8 bits_offset, struct btf_show *show)
2792{
2793	if (btf->resolved_ids)
2794		t = btf_type_id_resolve(btf, &type_id);
2795	else
2796		t = btf_type_skip_modifiers(btf, type_id, NULL);
2797
2798	btf_type_ops(t)->show(btf, t, type_id, data, bits_offset, show);
2799}
2800
2801static void btf_var_show(const struct btf *btf, const struct btf_type *t,
2802			 u32 type_id, void *data, u8 bits_offset,
2803			 struct btf_show *show)
2804{
2805	t = btf_type_id_resolve(btf, &type_id);
2806
2807	btf_type_ops(t)->show(btf, t, type_id, data, bits_offset, show);
2808}
2809
2810static void btf_ptr_show(const struct btf *btf, const struct btf_type *t,
2811			 u32 type_id, void *data, u8 bits_offset,
2812			 struct btf_show *show)
2813{
2814	void *safe_data;
2815
2816	safe_data = btf_show_start_type(show, t, type_id, data);
2817	if (!safe_data)
2818		return;
2819
2820	/* It is a hashed value unless BTF_SHOW_PTR_RAW is specified */
2821	if (show->flags & BTF_SHOW_PTR_RAW)
2822		btf_show_type_value(show, "0x%px", *(void **)safe_data);
2823	else
2824		btf_show_type_value(show, "0x%p", *(void **)safe_data);
2825	btf_show_end_type(show);
2826}
2827
2828static void btf_ref_type_log(struct btf_verifier_env *env,
2829			     const struct btf_type *t)
2830{
2831	btf_verifier_log(env, "type_id=%u", t->type);
2832}
2833
2834static const struct btf_kind_operations modifier_ops = {
2835	.check_meta = btf_ref_type_check_meta,
2836	.resolve = btf_modifier_resolve,
2837	.check_member = btf_modifier_check_member,
2838	.check_kflag_member = btf_modifier_check_kflag_member,
2839	.log_details = btf_ref_type_log,
2840	.show = btf_modifier_show,
2841};
2842
2843static const struct btf_kind_operations ptr_ops = {
2844	.check_meta = btf_ref_type_check_meta,
2845	.resolve = btf_ptr_resolve,
2846	.check_member = btf_ptr_check_member,
2847	.check_kflag_member = btf_generic_check_kflag_member,
2848	.log_details = btf_ref_type_log,
2849	.show = btf_ptr_show,
2850};
2851
2852static s32 btf_fwd_check_meta(struct btf_verifier_env *env,
2853			      const struct btf_type *t,
2854			      u32 meta_left)
2855{
2856	if (btf_type_vlen(t)) {
2857		btf_verifier_log_type(env, t, "vlen != 0");
2858		return -EINVAL;
2859	}
2860
2861	if (t->type) {
2862		btf_verifier_log_type(env, t, "type != 0");
2863		return -EINVAL;
2864	}
2865
2866	/* fwd type must have a valid name */
2867	if (!t->name_off ||
2868	    !btf_name_valid_identifier(env->btf, t->name_off)) {
2869		btf_verifier_log_type(env, t, "Invalid name");
2870		return -EINVAL;
2871	}
2872
2873	btf_verifier_log_type(env, t, NULL);
2874
2875	return 0;
2876}
2877
2878static void btf_fwd_type_log(struct btf_verifier_env *env,
2879			     const struct btf_type *t)
2880{
2881	btf_verifier_log(env, "%s", btf_type_kflag(t) ? "union" : "struct");
2882}
2883
2884static const struct btf_kind_operations fwd_ops = {
2885	.check_meta = btf_fwd_check_meta,
2886	.resolve = btf_df_resolve,
2887	.check_member = btf_df_check_member,
2888	.check_kflag_member = btf_df_check_kflag_member,
2889	.log_details = btf_fwd_type_log,
2890	.show = btf_df_show,
2891};
2892
2893static int btf_array_check_member(struct btf_verifier_env *env,
2894				  const struct btf_type *struct_type,
2895				  const struct btf_member *member,
2896				  const struct btf_type *member_type)
2897{
2898	u32 struct_bits_off = member->offset;
2899	u32 struct_size, bytes_offset;
2900	u32 array_type_id, array_size;
2901	struct btf *btf = env->btf;
2902
2903	if (BITS_PER_BYTE_MASKED(struct_bits_off)) {
2904		btf_verifier_log_member(env, struct_type, member,
2905					"Member is not byte aligned");
2906		return -EINVAL;
2907	}
2908
2909	array_type_id = member->type;
2910	btf_type_id_size(btf, &array_type_id, &array_size);
2911	struct_size = struct_type->size;
2912	bytes_offset = BITS_ROUNDDOWN_BYTES(struct_bits_off);
2913	if (struct_size - bytes_offset < array_size) {
2914		btf_verifier_log_member(env, struct_type, member,
2915					"Member exceeds struct_size");
2916		return -EINVAL;
2917	}
2918
2919	return 0;
2920}
2921
2922static s32 btf_array_check_meta(struct btf_verifier_env *env,
2923				const struct btf_type *t,
2924				u32 meta_left)
2925{
2926	const struct btf_array *array = btf_type_array(t);
2927	u32 meta_needed = sizeof(*array);
2928
2929	if (meta_left < meta_needed) {
2930		btf_verifier_log_basic(env, t,
2931				       "meta_left:%u meta_needed:%u",
2932				       meta_left, meta_needed);
2933		return -EINVAL;
2934	}
2935
2936	/* array type should not have a name */
2937	if (t->name_off) {
2938		btf_verifier_log_type(env, t, "Invalid name");
2939		return -EINVAL;
2940	}
2941
2942	if (btf_type_vlen(t)) {
2943		btf_verifier_log_type(env, t, "vlen != 0");
2944		return -EINVAL;
2945	}
2946
2947	if (btf_type_kflag(t)) {
2948		btf_verifier_log_type(env, t, "Invalid btf_info kind_flag");
2949		return -EINVAL;
2950	}
2951
2952	if (t->size) {
2953		btf_verifier_log_type(env, t, "size != 0");
2954		return -EINVAL;
2955	}
2956
2957	/* Array elem type and index type cannot be in type void,
2958	 * so !array->type and !array->index_type are not allowed.
2959	 */
2960	if (!array->type || !BTF_TYPE_ID_VALID(array->type)) {
2961		btf_verifier_log_type(env, t, "Invalid elem");
2962		return -EINVAL;
2963	}
2964
2965	if (!array->index_type || !BTF_TYPE_ID_VALID(array->index_type)) {
2966		btf_verifier_log_type(env, t, "Invalid index");
2967		return -EINVAL;
2968	}
2969
2970	btf_verifier_log_type(env, t, NULL);
2971
2972	return meta_needed;
2973}
2974
2975static int btf_array_resolve(struct btf_verifier_env *env,
2976			     const struct resolve_vertex *v)
2977{
2978	const struct btf_array *array = btf_type_array(v->t);
2979	const struct btf_type *elem_type, *index_type;
2980	u32 elem_type_id, index_type_id;
2981	struct btf *btf = env->btf;
2982	u32 elem_size;
2983
2984	/* Check array->index_type */
2985	index_type_id = array->index_type;
2986	index_type = btf_type_by_id(btf, index_type_id);
2987	if (btf_type_nosize_or_null(index_type) ||
2988	    btf_type_is_resolve_source_only(index_type)) {
2989		btf_verifier_log_type(env, v->t, "Invalid index");
2990		return -EINVAL;
2991	}
2992
2993	if (!env_type_is_resolve_sink(env, index_type) &&
2994	    !env_type_is_resolved(env, index_type_id))
2995		return env_stack_push(env, index_type, index_type_id);
2996
2997	index_type = btf_type_id_size(btf, &index_type_id, NULL);
2998	if (!index_type || !btf_type_is_int(index_type) ||
2999	    !btf_type_int_is_regular(index_type)) {
3000		btf_verifier_log_type(env, v->t, "Invalid index");
3001		return -EINVAL;
3002	}
3003
3004	/* Check array->type */
3005	elem_type_id = array->type;
3006	elem_type = btf_type_by_id(btf, elem_type_id);
3007	if (btf_type_nosize_or_null(elem_type) ||
3008	    btf_type_is_resolve_source_only(elem_type)) {
3009		btf_verifier_log_type(env, v->t,
3010				      "Invalid elem");
3011		return -EINVAL;
3012	}
3013
3014	if (!env_type_is_resolve_sink(env, elem_type) &&
3015	    !env_type_is_resolved(env, elem_type_id))
3016		return env_stack_push(env, elem_type, elem_type_id);
3017
3018	elem_type = btf_type_id_size(btf, &elem_type_id, &elem_size);
3019	if (!elem_type) {
3020		btf_verifier_log_type(env, v->t, "Invalid elem");
3021		return -EINVAL;
3022	}
3023
3024	if (btf_type_is_int(elem_type) && !btf_type_int_is_regular(elem_type)) {
3025		btf_verifier_log_type(env, v->t, "Invalid array of int");
3026		return -EINVAL;
3027	}
3028
3029	if (array->nelems && elem_size > U32_MAX / array->nelems) {
3030		btf_verifier_log_type(env, v->t,
3031				      "Array size overflows U32_MAX");
3032		return -EINVAL;
3033	}
3034
3035	env_stack_pop_resolved(env, elem_type_id, elem_size * array->nelems);
3036
3037	return 0;
3038}
3039
3040static void btf_array_log(struct btf_verifier_env *env,
3041			  const struct btf_type *t)
3042{
3043	const struct btf_array *array = btf_type_array(t);
3044
3045	btf_verifier_log(env, "type_id=%u index_type_id=%u nr_elems=%u",
3046			 array->type, array->index_type, array->nelems);
3047}
3048
3049static void __btf_array_show(const struct btf *btf, const struct btf_type *t,
3050			     u32 type_id, void *data, u8 bits_offset,
3051			     struct btf_show *show)
3052{
3053	const struct btf_array *array = btf_type_array(t);
3054	const struct btf_kind_operations *elem_ops;
3055	const struct btf_type *elem_type;
3056	u32 i, elem_size = 0, elem_type_id;
3057	u16 encoding = 0;
3058
3059	elem_type_id = array->type;
3060	elem_type = btf_type_skip_modifiers(btf, elem_type_id, NULL);
3061	if (elem_type && btf_type_has_size(elem_type))
3062		elem_size = elem_type->size;
3063
3064	if (elem_type && btf_type_is_int(elem_type)) {
3065		u32 int_type = btf_type_int(elem_type);
3066
3067		encoding = BTF_INT_ENCODING(int_type);
3068
3069		/*
3070		 * BTF_INT_CHAR encoding never seems to be set for
3071		 * char arrays, so if size is 1 and element is
3072		 * printable as a char, we'll do that.
3073		 */
3074		if (elem_size == 1)
3075			encoding = BTF_INT_CHAR;
3076	}
3077
3078	if (!btf_show_start_array_type(show, t, type_id, encoding, data))
3079		return;
3080
3081	if (!elem_type)
3082		goto out;
3083	elem_ops = btf_type_ops(elem_type);
3084
3085	for (i = 0; i < array->nelems; i++) {
3086
3087		btf_show_start_array_member(show);
3088
3089		elem_ops->show(btf, elem_type, elem_type_id, data,
3090			       bits_offset, show);
3091		data += elem_size;
3092
3093		btf_show_end_array_member(show);
3094
3095		if (show->state.array_terminated)
3096			break;
3097	}
3098out:
3099	btf_show_end_array_type(show);
3100}
3101
3102static void btf_array_show(const struct btf *btf, const struct btf_type *t,
3103			   u32 type_id, void *data, u8 bits_offset,
3104			   struct btf_show *show)
3105{
3106	const struct btf_member *m = show->state.member;
3107
3108	/*
3109	 * First check if any members would be shown (are non-zero).
3110	 * See comments above "struct btf_show" definition for more
3111	 * details on how this works at a high-level.
3112	 */
3113	if (show->state.depth > 0 && !(show->flags & BTF_SHOW_ZERO)) {
3114		if (!show->state.depth_check) {
3115			show->state.depth_check = show->state.depth + 1;
3116			show->state.depth_to_show = 0;
3117		}
3118		__btf_array_show(btf, t, type_id, data, bits_offset, show);
3119		show->state.member = m;
3120
3121		if (show->state.depth_check != show->state.depth + 1)
3122			return;
3123		show->state.depth_check = 0;
3124
3125		if (show->state.depth_to_show <= show->state.depth)
3126			return;
3127		/*
3128		 * Reaching here indicates we have recursed and found
3129		 * non-zero array member(s).
3130		 */
3131	}
3132	__btf_array_show(btf, t, type_id, data, bits_offset, show);
3133}
3134
3135static const struct btf_kind_operations array_ops = {
3136	.check_meta = btf_array_check_meta,
3137	.resolve = btf_array_resolve,
3138	.check_member = btf_array_check_member,
3139	.check_kflag_member = btf_generic_check_kflag_member,
3140	.log_details = btf_array_log,
3141	.show = btf_array_show,
3142};
3143
3144static int btf_struct_check_member(struct btf_verifier_env *env,
3145				   const struct btf_type *struct_type,
3146				   const struct btf_member *member,
3147				   const struct btf_type *member_type)
3148{
3149	u32 struct_bits_off = member->offset;
3150	u32 struct_size, bytes_offset;
3151
3152	if (BITS_PER_BYTE_MASKED(struct_bits_off)) {
3153		btf_verifier_log_member(env, struct_type, member,
3154					"Member is not byte aligned");
3155		return -EINVAL;
3156	}
3157
3158	struct_size = struct_type->size;
3159	bytes_offset = BITS_ROUNDDOWN_BYTES(struct_bits_off);
3160	if (struct_size - bytes_offset < member_type->size) {
3161		btf_verifier_log_member(env, struct_type, member,
3162					"Member exceeds struct_size");
3163		return -EINVAL;
3164	}
3165
3166	return 0;
3167}
3168
3169static s32 btf_struct_check_meta(struct btf_verifier_env *env,
3170				 const struct btf_type *t,
3171				 u32 meta_left)
3172{
3173	bool is_union = BTF_INFO_KIND(t->info) == BTF_KIND_UNION;
3174	const struct btf_member *member;
3175	u32 meta_needed, last_offset;
3176	struct btf *btf = env->btf;
3177	u32 struct_size = t->size;
3178	u32 offset;
3179	u16 i;
3180
3181	meta_needed = btf_type_vlen(t) * sizeof(*member);
3182	if (meta_left < meta_needed) {
3183		btf_verifier_log_basic(env, t,
3184				       "meta_left:%u meta_needed:%u",
3185				       meta_left, meta_needed);
3186		return -EINVAL;
3187	}
3188
3189	/* struct type either no name or a valid one */
3190	if (t->name_off &&
3191	    !btf_name_valid_identifier(env->btf, t->name_off)) {
3192		btf_verifier_log_type(env, t, "Invalid name");
3193		return -EINVAL;
3194	}
3195
3196	btf_verifier_log_type(env, t, NULL);
3197
3198	last_offset = 0;
3199	for_each_member(i, t, member) {
3200		if (!btf_name_offset_valid(btf, member->name_off)) {
3201			btf_verifier_log_member(env, t, member,
3202						"Invalid member name_offset:%u",
3203						member->name_off);
3204			return -EINVAL;
3205		}
3206
3207		/* struct member either no name or a valid one */
3208		if (member->name_off &&
3209		    !btf_name_valid_identifier(btf, member->name_off)) {
3210			btf_verifier_log_member(env, t, member, "Invalid name");
3211			return -EINVAL;
3212		}
3213		/* A member cannot be in type void */
3214		if (!member->type || !BTF_TYPE_ID_VALID(member->type)) {
3215			btf_verifier_log_member(env, t, member,
3216						"Invalid type_id");
3217			return -EINVAL;
3218		}
3219
3220		offset = __btf_member_bit_offset(t, member);
3221		if (is_union && offset) {
3222			btf_verifier_log_member(env, t, member,
3223						"Invalid member bits_offset");
3224			return -EINVAL;
3225		}
3226
3227		/*
3228		 * ">" instead of ">=" because the last member could be
3229		 * "char a[0];"
3230		 */
3231		if (last_offset > offset) {
3232			btf_verifier_log_member(env, t, member,
3233						"Invalid member bits_offset");
3234			return -EINVAL;
3235		}
3236
3237		if (BITS_ROUNDUP_BYTES(offset) > struct_size) {
3238			btf_verifier_log_member(env, t, member,
3239						"Member bits_offset exceeds its struct size");
3240			return -EINVAL;
3241		}
3242
3243		btf_verifier_log_member(env, t, member, NULL);
3244		last_offset = offset;
3245	}
3246
3247	return meta_needed;
3248}
3249
3250static int btf_struct_resolve(struct btf_verifier_env *env,
3251			      const struct resolve_vertex *v)
3252{
3253	const struct btf_member *member;
3254	int err;
3255	u16 i;
3256
3257	/* Before continue resolving the next_member,
3258	 * ensure the last member is indeed resolved to a
3259	 * type with size info.
3260	 */
3261	if (v->next_member) {
3262		const struct btf_type *last_member_type;
3263		const struct btf_member *last_member;
3264		u32 last_member_type_id;
3265
3266		last_member = btf_type_member(v->t) + v->next_member - 1;
3267		last_member_type_id = last_member->type;
3268		if (WARN_ON_ONCE(!env_type_is_resolved(env,
3269						       last_member_type_id)))
3270			return -EINVAL;
3271
3272		last_member_type = btf_type_by_id(env->btf,
3273						  last_member_type_id);
3274		if (btf_type_kflag(v->t))
3275			err = btf_type_ops(last_member_type)->check_kflag_member(env, v->t,
3276								last_member,
3277								last_member_type);
3278		else
3279			err = btf_type_ops(last_member_type)->check_member(env, v->t,
3280								last_member,
3281								last_member_type);
3282		if (err)
3283			return err;
3284	}
3285
3286	for_each_member_from(i, v->next_member, v->t, member) {
3287		u32 member_type_id = member->type;
3288		const struct btf_type *member_type = btf_type_by_id(env->btf,
3289								member_type_id);
3290
3291		if (btf_type_nosize_or_null(member_type) ||
3292		    btf_type_is_resolve_source_only(member_type)) {
3293			btf_verifier_log_member(env, v->t, member,
3294						"Invalid member");
3295			return -EINVAL;
3296		}
3297
3298		if (!env_type_is_resolve_sink(env, member_type) &&
3299		    !env_type_is_resolved(env, member_type_id)) {
3300			env_stack_set_next_member(env, i + 1);
3301			return env_stack_push(env, member_type, member_type_id);
3302		}
3303
3304		if (btf_type_kflag(v->t))
3305			err = btf_type_ops(member_type)->check_kflag_member(env, v->t,
3306									    member,
3307									    member_type);
3308		else
3309			err = btf_type_ops(member_type)->check_member(env, v->t,
3310								      member,
3311								      member_type);
3312		if (err)
3313			return err;
3314	}
3315
3316	env_stack_pop_resolved(env, 0, 0);
3317
3318	return 0;
3319}
3320
3321static void btf_struct_log(struct btf_verifier_env *env,
3322			   const struct btf_type *t)
3323{
3324	btf_verifier_log(env, "size=%u vlen=%u", t->size, btf_type_vlen(t));
3325}
3326
3327enum {
3328	BTF_FIELD_IGNORE = 0,
3329	BTF_FIELD_FOUND  = 1,
3330};
3331
3332struct btf_field_info {
3333	enum btf_field_type type;
3334	u32 off;
3335	union {
3336		struct {
3337			u32 type_id;
3338		} kptr;
3339		struct {
3340			const char *node_name;
3341			u32 value_btf_id;
3342		} graph_root;
3343	};
3344};
3345
3346static int btf_find_struct(const struct btf *btf, const struct btf_type *t,
3347			   u32 off, int sz, enum btf_field_type field_type,
3348			   struct btf_field_info *info)
3349{
3350	if (!__btf_type_is_struct(t))
3351		return BTF_FIELD_IGNORE;
3352	if (t->size != sz)
3353		return BTF_FIELD_IGNORE;
3354	info->type = field_type;
3355	info->off = off;
3356	return BTF_FIELD_FOUND;
3357}
3358
3359static int btf_find_kptr(const struct btf *btf, const struct btf_type *t,
3360			 u32 off, int sz, struct btf_field_info *info, u32 field_mask)
3361{
3362	enum btf_field_type type;
3363	const char *tag_value;
3364	bool is_type_tag;
3365	u32 res_id;
3366
3367	/* Permit modifiers on the pointer itself */
3368	if (btf_type_is_volatile(t))
3369		t = btf_type_by_id(btf, t->type);
3370	/* For PTR, sz is always == 8 */
3371	if (!btf_type_is_ptr(t))
3372		return BTF_FIELD_IGNORE;
3373	t = btf_type_by_id(btf, t->type);
3374	is_type_tag = btf_type_is_type_tag(t) && !btf_type_kflag(t);
3375	if (!is_type_tag)
3376		return BTF_FIELD_IGNORE;
3377	/* Reject extra tags */
3378	if (btf_type_is_type_tag(btf_type_by_id(btf, t->type)))
3379		return -EINVAL;
3380	tag_value = __btf_name_by_offset(btf, t->name_off);
3381	if (!strcmp("kptr_untrusted", tag_value))
3382		type = BPF_KPTR_UNREF;
3383	else if (!strcmp("kptr", tag_value))
3384		type = BPF_KPTR_REF;
3385	else if (!strcmp("percpu_kptr", tag_value))
3386		type = BPF_KPTR_PERCPU;
3387	else if (!strcmp("uptr", tag_value))
3388		type = BPF_UPTR;
3389	else
3390		return -EINVAL;
3391
3392	if (!(type & field_mask))
3393		return BTF_FIELD_IGNORE;
3394
3395	/* Get the base type */
3396	t = btf_type_skip_modifiers(btf, t->type, &res_id);
3397	/* Only pointer to struct is allowed */
3398	if (!__btf_type_is_struct(t))
3399		return -EINVAL;
3400
3401	info->type = type;
3402	info->off = off;
3403	info->kptr.type_id = res_id;
3404	return BTF_FIELD_FOUND;
3405}
3406
3407int btf_find_next_decl_tag(const struct btf *btf, const struct btf_type *pt,
3408			   int comp_idx, const char *tag_key, int last_id)
3409{
3410	int len = strlen(tag_key);
3411	int i, n;
3412
3413	for (i = last_id + 1, n = btf_nr_types(btf); i < n; i++) {
3414		const struct btf_type *t = btf_type_by_id(btf, i);
3415
3416		if (!btf_type_is_decl_tag(t))
3417			continue;
3418		if (pt != btf_type_by_id(btf, t->type))
3419			continue;
3420		if (btf_type_decl_tag(t)->component_idx != comp_idx)
3421			continue;
3422		if (strncmp(__btf_name_by_offset(btf, t->name_off), tag_key, len))
3423			continue;
3424		return i;
3425	}
3426	return -ENOENT;
3427}
3428
3429const char *btf_find_decl_tag_value(const struct btf *btf, const struct btf_type *pt,
3430				    int comp_idx, const char *tag_key)
3431{
3432	const char *value = NULL;
3433	const struct btf_type *t;
3434	int len, id;
3435
3436	id = btf_find_next_decl_tag(btf, pt, comp_idx, tag_key, 0);
3437	if (id < 0)
3438		return ERR_PTR(id);
3439
3440	t = btf_type_by_id(btf, id);
3441	len = strlen(tag_key);
3442	value = __btf_name_by_offset(btf, t->name_off) + len;
3443
3444	/* Prevent duplicate entries for same type */
3445	id = btf_find_next_decl_tag(btf, pt, comp_idx, tag_key, id);
3446	if (id >= 0)
3447		return ERR_PTR(-EEXIST);
3448
3449	return value;
3450}
3451
3452static int
3453btf_find_graph_root(const struct btf *btf, const struct btf_type *pt,
3454		    const struct btf_type *t, int comp_idx, u32 off,
3455		    int sz, struct btf_field_info *info,
3456		    enum btf_field_type head_type)
3457{
3458	const char *node_field_name;
3459	const char *value_type;
3460	s32 id;
3461
3462	if (!__btf_type_is_struct(t))
3463		return BTF_FIELD_IGNORE;
3464	if (t->size != sz)
3465		return BTF_FIELD_IGNORE;
3466	value_type = btf_find_decl_tag_value(btf, pt, comp_idx, "contains:");
3467	if (IS_ERR(value_type))
3468		return -EINVAL;
3469	node_field_name = strstr(value_type, ":");
3470	if (!node_field_name)
3471		return -EINVAL;
3472	value_type = kstrndup(value_type, node_field_name - value_type,
3473			      GFP_KERNEL_ACCOUNT | __GFP_NOWARN);
3474	if (!value_type)
3475		return -ENOMEM;
3476	id = btf_find_by_name_kind(btf, value_type, BTF_KIND_STRUCT);
3477	kfree(value_type);
3478	if (id < 0)
3479		return id;
3480	node_field_name++;
3481	if (str_is_empty(node_field_name))
3482		return -EINVAL;
3483	info->type = head_type;
3484	info->off = off;
3485	info->graph_root.value_btf_id = id;
3486	info->graph_root.node_name = node_field_name;
3487	return BTF_FIELD_FOUND;
3488}
3489
3490static int btf_get_field_type(const struct btf *btf, const struct btf_type *var_type,
3491			      u32 field_mask, u32 *seen_mask, int *align, int *sz)
3492{
3493	const struct {
3494		enum btf_field_type type;
3495		const char *const name;
3496		const bool is_unique;
3497	} field_types[] = {
3498		{ BPF_SPIN_LOCK, "bpf_spin_lock", true },
3499		{ BPF_RES_SPIN_LOCK, "bpf_res_spin_lock", true },
3500		{ BPF_TIMER, "bpf_timer", true },
3501		{ BPF_WORKQUEUE, "bpf_wq", true },
3502		{ BPF_TASK_WORK, "bpf_task_work", true },
3503		{ BPF_LIST_HEAD, "bpf_list_head", false },
3504		{ BPF_LIST_NODE, "bpf_list_node", false },
3505		{ BPF_RB_ROOT, "bpf_rb_root", false },
3506		{ BPF_RB_NODE, "bpf_rb_node", false },
3507		{ BPF_REFCOUNT, "bpf_refcount", false },
3508	};
3509	int type = 0, i;
3510	const char *name = __btf_name_by_offset(btf, var_type->name_off);
3511	const char *field_type_name;
3512	enum btf_field_type field_type;
3513	bool is_unique;
3514
3515	for (i = 0; i < ARRAY_SIZE(field_types); ++i) {
3516		field_type = field_types[i].type;
3517		field_type_name = field_types[i].name;
3518		is_unique = field_types[i].is_unique;
3519		if (!(field_mask & field_type) || strcmp(name, field_type_name))
3520			continue;
3521		if (is_unique) {
3522			if (*seen_mask & field_type)
3523				return -E2BIG;
3524			*seen_mask |= field_type;
3525		}
3526		type = field_type;
3527		goto end;
3528	}
3529
3530	/* Only return BPF_KPTR when all other types with matchable names fail */
3531	if (field_mask & (BPF_KPTR | BPF_UPTR) && !__btf_type_is_struct(var_type)) {
3532		type = BPF_KPTR_REF;
3533		goto end;
3534	}
3535	return 0;
3536end:
3537	*sz = btf_field_type_size(type);
3538	*align = btf_field_type_align(type);
3539	return type;
3540}
3541
3542/* Repeat a number of fields for a specified number of times.
3543 *
3544 * Copy the fields starting from the first field and repeat them for
3545 * repeat_cnt times. The fields are repeated by adding the offset of each
3546 * field with
3547 *   (i + 1) * elem_size
3548 * where i is the repeat index and elem_size is the size of an element.
3549 */
3550static int btf_repeat_fields(struct btf_field_info *info, int info_cnt,
3551			     u32 field_cnt, u32 repeat_cnt, u32 elem_size)
3552{
3553	u32 i, j;
3554	u32 cur;
3555
3556	/* Ensure not repeating fields that should not be repeated. */
3557	for (i = 0; i < field_cnt; i++) {
3558		switch (info[i].type) {
3559		case BPF_KPTR_UNREF:
3560		case BPF_KPTR_REF:
3561		case BPF_KPTR_PERCPU:
3562		case BPF_UPTR:
3563		case BPF_LIST_HEAD:
3564		case BPF_RB_ROOT:
3565			break;
3566		default:
3567			return -EINVAL;
3568		}
3569	}
3570
3571	/* The type of struct size or variable size is u32,
3572	 * so the multiplication will not overflow.
3573	 */
3574	if (field_cnt * (repeat_cnt + 1) > info_cnt)
3575		return -E2BIG;
3576
3577	cur = field_cnt;
3578	for (i = 0; i < repeat_cnt; i++) {
3579		memcpy(&info[cur], &info[0], field_cnt * sizeof(info[0]));
3580		for (j = 0; j < field_cnt; j++)
3581			info[cur++].off += (i + 1) * elem_size;
3582	}
3583
3584	return 0;
3585}
3586
3587static int btf_find_struct_field(const struct btf *btf,
3588				 const struct btf_type *t, u32 field_mask,
3589				 struct btf_field_info *info, int info_cnt,
3590				 u32 level);
3591
3592/* Find special fields in the struct type of a field.
3593 *
3594 * This function is used to find fields of special types that is not a
3595 * global variable or a direct field of a struct type. It also handles the
3596 * repetition if it is the element type of an array.
3597 */
3598static int btf_find_nested_struct(const struct btf *btf, const struct btf_type *t,
3599				  u32 off, u32 nelems,
3600				  u32 field_mask, struct btf_field_info *info,
3601				  int info_cnt, u32 level)
3602{
3603	int ret, err, i;
3604
3605	level++;
3606	if (level >= MAX_RESOLVE_DEPTH)
3607		return -E2BIG;
3608
3609	ret = btf_find_struct_field(btf, t, field_mask, info, info_cnt, level);
3610
3611	if (ret <= 0)
3612		return ret;
3613
3614	/* Shift the offsets of the nested struct fields to the offsets
3615	 * related to the container.
3616	 */
3617	for (i = 0; i < ret; i++)
3618		info[i].off += off;
3619
3620	if (nelems > 1) {
3621		err = btf_repeat_fields(info, info_cnt, ret, nelems - 1, t->size);
3622		if (err == 0)
3623			ret *= nelems;
3624		else
3625			ret = err;
3626	}
3627
3628	return ret;
3629}
3630
3631static int btf_find_field_one(const struct btf *btf,
3632			      const struct btf_type *var,
3633			      const struct btf_type *var_type,
3634			      int var_idx,
3635			      u32 off, u32 expected_size,
3636			      u32 field_mask, u32 *seen_mask,
3637			      struct btf_field_info *info, int info_cnt,
3638			      u32 level)
3639{
3640	int ret, align, sz, field_type;
3641	struct btf_field_info tmp;
3642	const struct btf_array *array;
3643	u32 i, nelems = 1;
3644
3645	/* Walk into array types to find the element type and the number of
3646	 * elements in the (flattened) array.
3647	 */
3648	for (i = 0; i < MAX_RESOLVE_DEPTH && btf_type_is_array(var_type); i++) {
3649		array = btf_array(var_type);
3650		nelems *= array->nelems;
3651		var_type = btf_type_by_id(btf, array->type);
3652	}
3653	if (i == MAX_RESOLVE_DEPTH)
3654		return -E2BIG;
3655	if (nelems == 0)
3656		return 0;
3657
3658	field_type = btf_get_field_type(btf, var_type,
3659					field_mask, seen_mask, &align, &sz);
3660	/* Look into variables of struct types */
3661	if (!field_type && __btf_type_is_struct(var_type)) {
3662		sz = var_type->size;
3663		if (expected_size && expected_size != sz * nelems)
3664			return 0;
3665		ret = btf_find_nested_struct(btf, var_type, off, nelems, field_mask,
3666					     &info[0], info_cnt, level);
3667		return ret;
3668	}
3669
3670	if (field_type == 0)
3671		return 0;
3672	if (field_type < 0)
3673		return field_type;
3674
3675	if (expected_size && expected_size != sz * nelems)
3676		return 0;
3677	if (off % align)
3678		return 0;
3679
3680	switch (field_type) {
3681	case BPF_SPIN_LOCK:
3682	case BPF_RES_SPIN_LOCK:
3683	case BPF_TIMER:
3684	case BPF_WORKQUEUE:
3685	case BPF_LIST_NODE:
3686	case BPF_RB_NODE:
3687	case BPF_REFCOUNT:
3688	case BPF_TASK_WORK:
3689		ret = btf_find_struct(btf, var_type, off, sz, field_type,
3690				      info_cnt ? &info[0] : &tmp);
3691		if (ret < 0)
3692			return ret;
3693		break;
3694	case BPF_KPTR_UNREF:
3695	case BPF_KPTR_REF:
3696	case BPF_KPTR_PERCPU:
3697	case BPF_UPTR:
3698		ret = btf_find_kptr(btf, var_type, off, sz,
3699				    info_cnt ? &info[0] : &tmp, field_mask);
3700		if (ret < 0)
3701			return ret;
3702		break;
3703	case BPF_LIST_HEAD:
3704	case BPF_RB_ROOT:
3705		ret = btf_find_graph_root(btf, var, var_type,
3706					  var_idx, off, sz,
3707					  info_cnt ? &info[0] : &tmp,
3708					  field_type);
3709		if (ret < 0)
3710			return ret;
3711		break;
3712	default:
3713		return -EFAULT;
3714	}
3715
3716	if (ret == BTF_FIELD_IGNORE)
3717		return 0;
3718	if (!info_cnt)
3719		return -E2BIG;
3720	if (nelems > 1) {
3721		ret = btf_repeat_fields(info, info_cnt, 1, nelems - 1, sz);
3722		if (ret < 0)
3723			return ret;
3724	}
3725	return nelems;
3726}
3727
3728static int btf_find_struct_field(const struct btf *btf,
3729				 const struct btf_type *t, u32 field_mask,
3730				 struct btf_field_info *info, int info_cnt,
3731				 u32 level)
3732{
3733	int ret, idx = 0;
3734	const struct btf_member *member;
3735	u32 i, off, seen_mask = 0;
3736
3737	for_each_member(i, t, member) {
3738		const struct btf_type *member_type = btf_type_by_id(btf,
3739								    member->type);
3740
3741		off = __btf_member_bit_offset(t, member);
3742		if (off % 8)
3743			/* valid C code cannot generate such BTF */
3744			return -EINVAL;
3745		off /= 8;
3746
3747		ret = btf_find_field_one(btf, t, member_type, i,
3748					 off, 0,
3749					 field_mask, &seen_mask,
3750					 &info[idx], info_cnt - idx, level);
3751		if (ret < 0)
3752			return ret;
3753		idx += ret;
3754	}
3755	return idx;
3756}
3757
3758static int btf_find_datasec_var(const struct btf *btf, const struct btf_type *t,
3759				u32 field_mask, struct btf_field_info *info,
3760				int info_cnt, u32 level)
3761{
3762	int ret, idx = 0;
3763	const struct btf_var_secinfo *vsi;
3764	u32 i, off, seen_mask = 0;
3765
3766	for_each_vsi(i, t, vsi) {
3767		const struct btf_type *var = btf_type_by_id(btf, vsi->type);
3768		const struct btf_type *var_type = btf_type_by_id(btf, var->type);
3769
3770		off = vsi->offset;
3771		ret = btf_find_field_one(btf, var, var_type, -1, off, vsi->size,
3772					 field_mask, &seen_mask,
3773					 &info[idx], info_cnt - idx,
3774					 level);
3775		if (ret < 0)
3776			return ret;
3777		idx += ret;
3778	}
3779	return idx;
3780}
3781
3782static int btf_find_field(const struct btf *btf, const struct btf_type *t,
3783			  u32 field_mask, struct btf_field_info *info,
3784			  int info_cnt)
3785{
3786	if (__btf_type_is_struct(t))
3787		return btf_find_struct_field(btf, t, field_mask, info, info_cnt, 0);
3788	else if (btf_type_is_datasec(t))
3789		return btf_find_datasec_var(btf, t, field_mask, info, info_cnt, 0);
3790	return -EINVAL;
3791}
3792
3793/* Callers have to ensure the life cycle of btf if it is program BTF */
3794static int btf_parse_kptr(const struct btf *btf, struct btf_field *field,
3795			  struct btf_field_info *info)
3796{
3797	struct module *mod = NULL;
3798	const struct btf_type *t;
3799	/* If a matching btf type is found in kernel or module BTFs, kptr_ref
3800	 * is that BTF, otherwise it's program BTF
3801	 */
3802	struct btf *kptr_btf;
3803	int ret;
3804	s32 id;
3805
3806	/* Find type in map BTF, and use it to look up the matching type
3807	 * in vmlinux or module BTFs, by name and kind.
3808	 */
3809	t = btf_type_by_id(btf, info->kptr.type_id);
3810	id = bpf_find_btf_id(__btf_name_by_offset(btf, t->name_off), BTF_INFO_KIND(t->info),
3811			     &kptr_btf);
3812	if (id == -ENOENT) {
3813		/* btf_parse_kptr should only be called w/ btf = program BTF */
3814		WARN_ON_ONCE(btf_is_kernel(btf));
3815
3816		/* Type exists only in program BTF. Assume that it's a MEM_ALLOC
3817		 * kptr allocated via bpf_obj_new
3818		 */
3819		field->kptr.dtor = NULL;
3820		id = info->kptr.type_id;
3821		kptr_btf = (struct btf *)btf;
3822		goto found_dtor;
3823	}
3824	if (id < 0)
3825		return id;
3826
3827	/* Find and stash the function pointer for the destruction function that
3828	 * needs to be eventually invoked from the map free path.
3829	 */
3830	if (info->type == BPF_KPTR_REF) {
3831		const struct btf_type *dtor_func;
3832		const char *dtor_func_name;
3833		unsigned long addr;
3834		s32 dtor_btf_id;
3835
3836		/* This call also serves as a whitelist of allowed objects that
3837		 * can be used as a referenced pointer and be stored in a map at
3838		 * the same time.
3839		 */
3840		dtor_btf_id = btf_find_dtor_kfunc(kptr_btf, id);
3841		if (dtor_btf_id < 0) {
3842			ret = dtor_btf_id;
3843			goto end_btf;
3844		}
3845
3846		dtor_func = btf_type_by_id(kptr_btf, dtor_btf_id);
3847		if (!dtor_func) {
3848			ret = -ENOENT;
3849			goto end_btf;
3850		}
3851
3852		if (btf_is_module(kptr_btf)) {
3853			mod = btf_try_get_module(kptr_btf);
3854			if (!mod) {
3855				ret = -ENXIO;
3856				goto end_btf;
3857			}
3858		}
3859
3860		/* We already verified dtor_func to be btf_type_is_func
3861		 * in register_btf_id_dtor_kfuncs.
3862		 */
3863		dtor_func_name = __btf_name_by_offset(kptr_btf, dtor_func->name_off);
3864		addr = kallsyms_lookup_name(dtor_func_name);
3865		if (!addr) {
3866			ret = -EINVAL;
3867			goto end_mod;
3868		}
3869		field->kptr.dtor = (void *)addr;
3870	}
3871
3872found_dtor:
3873	field->kptr.btf_id = id;
3874	field->kptr.btf = kptr_btf;
3875	field->kptr.module = mod;
3876	return 0;
3877end_mod:
3878	module_put(mod);
3879end_btf:
3880	btf_put(kptr_btf);
3881	return ret;
3882}
3883
3884static int btf_parse_graph_root(const struct btf *btf,
3885				struct btf_field *field,
3886				struct btf_field_info *info,
3887				const char *node_type_name,
3888				size_t node_type_align)
3889{
3890	const struct btf_type *t, *n = NULL;
3891	const struct btf_member *member;
3892	u32 offset;
3893	int i;
3894
3895	t = btf_type_by_id(btf, info->graph_root.value_btf_id);
3896	/* We've already checked that value_btf_id is a struct type. We
3897	 * just need to figure out the offset of the list_node, and
3898	 * verify its type.
3899	 */
3900	for_each_member(i, t, member) {
3901		if (strcmp(info->graph_root.node_name,
3902			   __btf_name_by_offset(btf, member->name_off)))
3903			continue;
3904		/* Invalid BTF, two members with same name */
3905		if (n)
3906			return -EINVAL;
3907		n = btf_type_by_id(btf, member->type);
3908		if (!__btf_type_is_struct(n))
3909			return -EINVAL;
3910		if (strcmp(node_type_name, __btf_name_by_offset(btf, n->name_off)))
3911			return -EINVAL;
3912		offset = __btf_member_bit_offset(n, member);
3913		if (offset % 8)
3914			return -EINVAL;
3915		offset /= 8;
3916		if (offset % node_type_align)
3917			return -EINVAL;
3918
3919		field->graph_root.btf = (struct btf *)btf;
3920		field->graph_root.value_btf_id = info->graph_root.value_btf_id;
3921		field->graph_root.node_offset = offset;
3922	}
3923	if (!n)
3924		return -ENOENT;
3925	return 0;
3926}
3927
3928static int btf_parse_list_head(const struct btf *btf, struct btf_field *field,
3929			       struct btf_field_info *info)
3930{
3931	return btf_parse_graph_root(btf, field, info, "bpf_list_node",
3932					    __alignof__(struct bpf_list_node));
3933}
3934
3935static int btf_parse_rb_root(const struct btf *btf, struct btf_field *field,
3936			     struct btf_field_info *info)
3937{
3938	return btf_parse_graph_root(btf, field, info, "bpf_rb_node",
3939					    __alignof__(struct bpf_rb_node));
3940}
3941
3942static int btf_field_cmp(const void *_a, const void *_b, const void *priv)
3943{
3944	const struct btf_field *a = (const struct btf_field *)_a;
3945	const struct btf_field *b = (const struct btf_field *)_b;
3946
3947	if (a->offset < b->offset)
3948		return -1;
3949	else if (a->offset > b->offset)
3950		return 1;
3951	return 0;
3952}
3953
3954struct btf_record *btf_parse_fields(const struct btf *btf, const struct btf_type *t,
3955				    u32 field_mask, u32 value_size)
3956{
3957	struct btf_field_info info_arr[BTF_FIELDS_MAX];
3958	u32 next_off = 0, field_type_size;
3959	struct btf_record *rec;
3960	int ret, i, cnt;
3961
3962	ret = btf_find_field(btf, t, field_mask, info_arr, ARRAY_SIZE(info_arr));
3963	if (ret < 0)
3964		return ERR_PTR(ret);
3965	if (!ret)
3966		return NULL;
3967
3968	cnt = ret;
3969	/* This needs to be kzalloc to zero out padding and unused fields, see
3970	 * comment in btf_record_equal.
3971	 */
3972	rec = kzalloc(struct_size(rec, fields, cnt), GFP_KERNEL_ACCOUNT | __GFP_NOWARN);
3973	if (!rec)
3974		return ERR_PTR(-ENOMEM);
3975
3976	rec->spin_lock_off = -EINVAL;
3977	rec->res_spin_lock_off = -EINVAL;
3978	rec->timer_off = -EINVAL;
3979	rec->wq_off = -EINVAL;
3980	rec->refcount_off = -EINVAL;
3981	rec->task_work_off = -EINVAL;
3982	for (i = 0; i < cnt; i++) {
3983		field_type_size = btf_field_type_size(info_arr[i].type);
3984		if (info_arr[i].off + field_type_size > value_size) {
3985			WARN_ONCE(1, "verifier bug off %d size %d", info_arr[i].off, value_size);
3986			ret = -EFAULT;
3987			goto end;
3988		}
3989		if (info_arr[i].off < next_off) {
3990			ret = -EEXIST;
3991			goto end;
3992		}
3993		next_off = info_arr[i].off + field_type_size;
3994
3995		rec->field_mask |= info_arr[i].type;
3996		rec->fields[i].offset = info_arr[i].off;
3997		rec->fields[i].type = info_arr[i].type;
3998		rec->fields[i].size = field_type_size;
3999
4000		switch (info_arr[i].type) {
4001		case BPF_SPIN_LOCK:
4002			WARN_ON_ONCE(rec->spin_lock_off >= 0);
4003			/* Cache offset for faster lookup at runtime */
4004			rec->spin_lock_off = rec->fields[i].offset;
4005			break;
4006		case BPF_RES_SPIN_LOCK:
4007			WARN_ON_ONCE(rec->spin_lock_off >= 0);
4008			/* Cache offset for faster lookup at runtime */
4009			rec->res_spin_lock_off = rec->fields[i].offset;
4010			break;
4011		case BPF_TIMER:
4012			WARN_ON_ONCE(rec->timer_off >= 0);
4013			/* Cache offset for faster lookup at runtime */
4014			rec->timer_off = rec->fields[i].offset;
4015			break;
4016		case BPF_WORKQUEUE:
4017			WARN_ON_ONCE(rec->wq_off >= 0);
4018			/* Cache offset for faster lookup at runtime */
4019			rec->wq_off = rec->fields[i].offset;
4020			break;
4021		case BPF_TASK_WORK:
4022			WARN_ON_ONCE(rec->task_work_off >= 0);
4023			rec->task_work_off = rec->fields[i].offset;
4024			break;
4025		case BPF_REFCOUNT:
4026			WARN_ON_ONCE(rec->refcount_off >= 0);
4027			/* Cache offset for faster lookup at runtime */
4028			rec->refcount_off = rec->fields[i].offset;
4029			break;
4030		case BPF_KPTR_UNREF:
4031		case BPF_KPTR_REF:
4032		case BPF_KPTR_PERCPU:
4033		case BPF_UPTR:
4034			ret = btf_parse_kptr(btf, &rec->fields[i], &info_arr[i]);
4035			if (ret < 0)
4036				goto end;
4037			break;
4038		case BPF_LIST_HEAD:
4039			ret = btf_parse_list_head(btf, &rec->fields[i], &info_arr[i]);
4040			if (ret < 0)
4041				goto end;
4042			break;
4043		case BPF_RB_ROOT:
4044			ret = btf_parse_rb_root(btf, &rec->fields[i], &info_arr[i]);
4045			if (ret < 0)
4046				goto end;
4047			break;
4048		case BPF_LIST_NODE:
4049		case BPF_RB_NODE:
4050			break;
4051		default:
4052			ret = -EFAULT;
4053			goto end;
4054		}
4055		rec->cnt++;
4056	}
4057
4058	if (rec->spin_lock_off >= 0 && rec->res_spin_lock_off >= 0) {
4059		ret = -EINVAL;
4060		goto end;
4061	}
4062
4063	/* bpf_{list_head, rb_node} require bpf_spin_lock */
4064	if ((btf_record_has_field(rec, BPF_LIST_HEAD) ||
4065	     btf_record_has_field(rec, BPF_RB_ROOT)) &&
4066		 (rec->spin_lock_off < 0 && rec->res_spin_lock_off < 0)) {
4067		ret = -EINVAL;
4068		goto end;
4069	}
4070
4071	if (rec->refcount_off < 0 &&
4072	    btf_record_has_field(rec, BPF_LIST_NODE) &&
4073	    btf_record_has_field(rec, BPF_RB_NODE)) {
4074		ret = -EINVAL;
4075		goto end;
4076	}
4077
4078	sort_r(rec->fields, rec->cnt, sizeof(struct btf_field), btf_field_cmp,
4079	       NULL, rec);
4080
4081	return rec;
4082end:
4083	btf_record_free(rec);
4084	return ERR_PTR(ret);
4085}
4086
4087int btf_check_and_fixup_fields(const struct btf *btf, struct btf_record *rec)
4088{
4089	int i;
4090
4091	/* There are three types that signify ownership of some other type:
4092	 *  kptr_ref, bpf_list_head, bpf_rb_root.
4093	 * kptr_ref only supports storing kernel types, which can't store
4094	 * references to program allocated local types.
4095	 *
4096	 * Hence we only need to ensure that bpf_{list_head,rb_root} ownership
4097	 * does not form cycles.
4098	 */
4099	if (IS_ERR_OR_NULL(rec) || !(rec->field_mask & (BPF_GRAPH_ROOT | BPF_UPTR)))
4100		return 0;
4101	for (i = 0; i < rec->cnt; i++) {
4102		struct btf_struct_meta *meta;
4103		const struct btf_type *t;
4104		u32 btf_id;
4105
4106		if (rec->fields[i].type == BPF_UPTR) {
4107			/* The uptr only supports pinning one page and cannot
4108			 * point to a kernel struct
4109			 */
4110			if (btf_is_kernel(rec->fields[i].kptr.btf))
4111				return -EINVAL;
4112			t = btf_type_by_id(rec->fields[i].kptr.btf,
4113					   rec->fields[i].kptr.btf_id);
4114			if (!t->size)
4115				return -EINVAL;
4116			if (t->size > PAGE_SIZE)
4117				return -E2BIG;
4118			continue;
4119		}
4120
4121		if (!(rec->fields[i].type & BPF_GRAPH_ROOT))
4122			continue;
4123		btf_id = rec->fields[i].graph_root.value_btf_id;
4124		meta = btf_find_struct_meta(btf, btf_id);
4125		if (!meta)
4126			return -EFAULT;
4127		rec->fields[i].graph_root.value_rec = meta->record;
4128
4129		/* We need to set value_rec for all root types, but no need
4130		 * to check ownership cycle for a type unless it's also a
4131		 * node type.
4132		 */
4133		if (!(rec->field_mask & BPF_GRAPH_NODE))
4134			continue;
4135
4136		/* We need to ensure ownership acyclicity among all types. The
4137		 * proper way to do it would be to topologically sort all BTF
4138		 * IDs based on the ownership edges, since there can be multiple
4139		 * bpf_{list_head,rb_node} in a type. Instead, we use the
4140		 * following resaoning:
4141		 *
4142		 * - A type can only be owned by another type in user BTF if it
4143		 *   has a bpf_{list,rb}_node. Let's call these node types.
4144		 * - A type can only _own_ another type in user BTF if it has a
4145		 *   bpf_{list_head,rb_root}. Let's call these root types.
4146		 *
4147		 * We ensure that if a type is both a root and node, its
4148		 * element types cannot be root types.
4149		 *
4150		 * To ensure acyclicity:
4151		 *
4152		 * When A is an root type but not a node, its ownership
4153		 * chain can be:
4154		 *	A -> B -> C
4155		 * Where:
4156		 * - A is an root, e.g. has bpf_rb_root.
4157		 * - B is both a root and node, e.g. has bpf_rb_node and
4158		 *   bpf_list_head.
4159		 * - C is only an root, e.g. has bpf_list_node
4160		 *
4161		 * When A is both a root and node, some other type already
4162		 * owns it in the BTF domain, hence it can not own
4163		 * another root type through any of the ownership edges.
4164		 *	A -> B
4165		 * Where:
4166		 * - A is both an root and node.
4167		 * - B is only an node.
4168		 */
4169		if (meta->record->field_mask & BPF_GRAPH_ROOT)
4170			return -ELOOP;
4171	}
4172	return 0;
4173}
4174
4175static void __btf_struct_show(const struct btf *btf, const struct btf_type *t,
4176			      u32 type_id, void *data, u8 bits_offset,
4177			      struct btf_show *show)
4178{
4179	const struct btf_member *member;
4180	void *safe_data;
4181	u32 i;
4182
4183	safe_data = btf_show_start_struct_type(show, t, type_id, data);
4184	if (!safe_data)
4185		return;
4186
4187	for_each_member(i, t, member) {
4188		const struct btf_type *member_type = btf_type_by_id(btf,
4189								member->type);
4190		const struct btf_kind_operations *ops;
4191		u32 member_offset, bitfield_size;
4192		u32 bytes_offset;
4193		u8 bits8_offset;
4194
4195		btf_show_start_member(show, member);
4196
4197		member_offset = __btf_member_bit_offset(t, member);
4198		bitfield_size = __btf_member_bitfield_size(t, member);
4199		bytes_offset = BITS_ROUNDDOWN_BYTES(member_offset);
4200		bits8_offset = BITS_PER_BYTE_MASKED(member_offset);
4201		if (bitfield_size) {
4202			safe_data = btf_show_start_type(show, member_type,
4203							member->type,
4204							data + bytes_offset);
4205			if (safe_data)
4206				btf_bitfield_show(safe_data,
4207						  bits8_offset,
4208						  bitfield_size, show);
4209			btf_show_end_type(show);
4210		} else {
4211			ops = btf_type_ops(member_type);
4212			ops->show(btf, member_type, member->type,
4213				  data + bytes_offset, bits8_offset, show);
4214		}
4215
4216		btf_show_end_member(show);
4217	}
4218
4219	btf_show_end_struct_type(show);
4220}
4221
4222static void btf_struct_show(const struct btf *btf, const struct btf_type *t,
4223			    u32 type_id, void *data, u8 bits_offset,
4224			    struct btf_show *show)
4225{
4226	const struct btf_member *m = show->state.member;
4227
4228	/*
4229	 * First check if any members would be shown (are non-zero).
4230	 * See comments above "struct btf_show" definition for more
4231	 * details on how this works at a high-level.
4232	 */
4233	if (show->state.depth > 0 && !(show->flags & BTF_SHOW_ZERO)) {
4234		if (!show->state.depth_check) {
4235			show->state.depth_check = show->state.depth + 1;
4236			show->state.depth_to_show = 0;
4237		}
4238		__btf_struct_show(btf, t, type_id, data, bits_offset, show);
4239		/* Restore saved member data here */
4240		show->state.member = m;
4241		if (show->state.depth_check != show->state.depth + 1)
4242			return;
4243		show->state.depth_check = 0;
4244
4245		if (show->state.depth_to_show <= show->state.depth)
4246			return;
4247		/*
4248		 * Reaching here indicates we have recursed and found
4249		 * non-zero child values.
4250		 */
4251	}
4252
4253	__btf_struct_show(btf, t, type_id, data, bits_offset, show);
4254}
4255
4256static const struct btf_kind_operations struct_ops = {
4257	.check_meta = btf_struct_check_meta,
4258	.resolve = btf_struct_resolve,
4259	.check_member = btf_struct_check_member,
4260	.check_kflag_member = btf_generic_check_kflag_member,
4261	.log_details = btf_struct_log,
4262	.show = btf_struct_show,
4263};
4264
4265static int btf_enum_check_member(struct btf_verifier_env *env,
4266				 const struct btf_type *struct_type,
4267				 const struct btf_member *member,
4268				 const struct btf_type *member_type)
4269{
4270	u32 struct_bits_off = member->offset;
4271	u32 struct_size, bytes_offset;
4272
4273	if (BITS_PER_BYTE_MASKED(struct_bits_off)) {
4274		btf_verifier_log_member(env, struct_type, member,
4275					"Member is not byte aligned");
4276		return -EINVAL;
4277	}
4278
4279	struct_size = struct_type->size;
4280	bytes_offset = BITS_ROUNDDOWN_BYTES(struct_bits_off);
4281	if (struct_size - bytes_offset < member_type->size) {
4282		btf_verifier_log_member(env, struct_type, member,
4283					"Member exceeds struct_size");
4284		return -EINVAL;
4285	}
4286
4287	return 0;
4288}
4289
4290static int btf_enum_check_kflag_member(struct btf_verifier_env *env,
4291				       const struct btf_type *struct_type,
4292				       const struct btf_member *member,
4293				       const struct btf_type *member_type)
4294{
4295	u32 struct_bits_off, nr_bits, bytes_end, struct_size;
4296	u32 int_bitsize = sizeof(int) * BITS_PER_BYTE;
4297
4298	struct_bits_off = BTF_MEMBER_BIT_OFFSET(member->offset);
4299	nr_bits = BTF_MEMBER_BITFIELD_SIZE(member->offset);
4300	if (!nr_bits) {
4301		if (BITS_PER_BYTE_MASKED(struct_bits_off)) {
4302			btf_verifier_log_member(env, struct_type, member,
4303						"Member is not byte aligned");
4304			return -EINVAL;
4305		}
4306
4307		nr_bits = int_bitsize;
4308	} else if (nr_bits > int_bitsize) {
4309		btf_verifier_log_member(env, struct_type, member,
4310					"Invalid member bitfield_size");
4311		return -EINVAL;
4312	}
4313
4314	struct_size = struct_type->size;
4315	bytes_end = BITS_ROUNDUP_BYTES(struct_bits_off + nr_bits);
4316	if (struct_size < bytes_end) {
4317		btf_verifier_log_member(env, struct_type, member,
4318					"Member exceeds struct_size");
4319		return -EINVAL;
4320	}
4321
4322	return 0;
4323}
4324
4325static s32 btf_enum_check_meta(struct btf_verifier_env *env,
4326			       const struct btf_type *t,
4327			       u32 meta_left)
4328{
4329	const struct btf_enum *enums = btf_type_enum(t);
4330	struct btf *btf = env->btf;
4331	const char *fmt_str;
4332	u16 i, nr_enums;
4333	u32 meta_needed;
4334
4335	nr_enums = btf_type_vlen(t);
4336	meta_needed = nr_enums * sizeof(*enums);
4337
4338	if (meta_left < meta_needed) {
4339		btf_verifier_log_basic(env, t,
4340				       "meta_left:%u meta_needed:%u",
4341				       meta_left, meta_needed);
4342		return -EINVAL;
4343	}
4344
4345	if (t->size > 8 || !is_power_of_2(t->size)) {
4346		btf_verifier_log_type(env, t, "Unexpected size");
4347		return -EINVAL;
4348	}
4349
4350	/* enum type either no name or a valid one */
4351	if (t->name_off &&
4352	    !btf_name_valid_identifier(env->btf, t->name_off)) {
4353		btf_verifier_log_type(env, t, "Invalid name");
4354		return -EINVAL;
4355	}
4356
4357	btf_verifier_log_type(env, t, NULL);
4358
4359	for (i = 0; i < nr_enums; i++) {
4360		if (!btf_name_offset_valid(btf, enums[i].name_off)) {
4361			btf_verifier_log(env, "\tInvalid name_offset:%u",
4362					 enums[i].name_off);
4363			return -EINVAL;
4364		}
4365
4366		/* enum member must have a valid name */
4367		if (!enums[i].name_off ||
4368		    !btf_name_valid_identifier(btf, enums[i].name_off)) {
4369			btf_verifier_log_type(env, t, "Invalid name");
4370			return -EINVAL;
4371		}
4372
4373		if (env->log.level == BPF_LOG_KERNEL)
4374			continue;
4375		fmt_str = btf_type_kflag(t) ? "\t%s val=%d\n" : "\t%s val=%u\n";
4376		btf_verifier_log(env, fmt_str,
4377				 __btf_name_by_offset(btf, enums[i].name_off),
4378				 enums[i].val);
4379	}
4380
4381	return meta_needed;
4382}
4383
4384static void btf_enum_log(struct btf_verifier_env *env,
4385			 const struct btf_type *t)
4386{
4387	btf_verifier_log(env, "size=%u vlen=%u", t->size, btf_type_vlen(t));
4388}
4389
4390static void btf_enum_show(const struct btf *btf, const struct btf_type *t,
4391			  u32 type_id, void *data, u8 bits_offset,
4392			  struct btf_show *show)
4393{
4394	const struct btf_enum *enums = btf_type_enum(t);
4395	u32 i, nr_enums = btf_type_vlen(t);
4396	void *safe_data;
4397	int v;
4398
4399	safe_data = btf_show_start_type(show, t, type_id, data);
4400	if (!safe_data)
4401		return;
4402
4403	v = *(int *)safe_data;
4404
4405	for (i = 0; i < nr_enums; i++) {
4406		if (v != enums[i].val)
4407			continue;
4408
4409		btf_show_type_value(show, "%s",
4410				    __btf_name_by_offset(btf,
4411							 enums[i].name_off));
4412
4413		btf_show_end_type(show);
4414		return;
4415	}
4416
4417	if (btf_type_kflag(t))
4418		btf_show_type_value(show, "%d", v);
4419	else
4420		btf_show_type_value(show, "%u", v);
4421	btf_show_end_type(show);
4422}
4423
4424static const struct btf_kind_operations enum_ops = {
4425	.check_meta = btf_enum_check_meta,
4426	.resolve = btf_df_resolve,
4427	.check_member = btf_enum_check_member,
4428	.check_kflag_member = btf_enum_check_kflag_member,
4429	.log_details = btf_enum_log,
4430	.show = btf_enum_show,
4431};
4432
4433static s32 btf_enum64_check_meta(struct btf_verifier_env *env,
4434				 const struct btf_type *t,
4435				 u32 meta_left)
4436{
4437	const struct btf_enum64 *enums = btf_type_enum64(t);
4438	struct btf *btf = env->btf;
4439	const char *fmt_str;
4440	u16 i, nr_enums;
4441	u32 meta_needed;
4442
4443	nr_enums = btf_type_vlen(t);
4444	meta_needed = nr_enums * sizeof(*enums);
4445
4446	if (meta_left < meta_needed) {
4447		btf_verifier_log_basic(env, t,
4448				       "meta_left:%u meta_needed:%u",
4449				       meta_left, meta_needed);
4450		return -EINVAL;
4451	}
4452
4453	if (t->size > 8 || !is_power_of_2(t->size)) {
4454		btf_verifier_log_type(env, t, "Unexpected size");
4455		return -EINVAL;
4456	}
4457
4458	/* enum type either no name or a valid one */
4459	if (t->name_off &&
4460	    !btf_name_valid_identifier(env->btf, t->name_off)) {
4461		btf_verifier_log_type(env, t, "Invalid name");
4462		return -EINVAL;
4463	}
4464
4465	btf_verifier_log_type(env, t, NULL);
4466
4467	for (i = 0; i < nr_enums; i++) {
4468		if (!btf_name_offset_valid(btf, enums[i].name_off)) {
4469			btf_verifier_log(env, "\tInvalid name_offset:%u",
4470					 enums[i].name_off);
4471			return -EINVAL;
4472		}
4473
4474		/* enum member must have a valid name */
4475		if (!enums[i].name_off ||
4476		    !btf_name_valid_identifier(btf, enums[i].name_off)) {
4477			btf_verifier_log_type(env, t, "Invalid name");
4478			return -EINVAL;
4479		}
4480
4481		if (env->log.level == BPF_LOG_KERNEL)
4482			continue;
4483
4484		fmt_str = btf_type_kflag(t) ? "\t%s val=%lld\n" : "\t%s val=%llu\n";
4485		btf_verifier_log(env, fmt_str,
4486				 __btf_name_by_offset(btf, enums[i].name_off),
4487				 btf_enum64_value(enums + i));
4488	}
4489
4490	return meta_needed;
4491}
4492
4493static void btf_enum64_show(const struct btf *btf, const struct btf_type *t,
4494			    u32 type_id, void *data, u8 bits_offset,
4495			    struct btf_show *show)
4496{
4497	const struct btf_enum64 *enums = btf_type_enum64(t);
4498	u32 i, nr_enums = btf_type_vlen(t);
4499	void *safe_data;
4500	s64 v;
4501
4502	safe_data = btf_show_start_type(show, t, type_id, data);
4503	if (!safe_data)
4504		return;
4505
4506	v = *(u64 *)safe_data;
4507
4508	for (i = 0; i < nr_enums; i++) {
4509		if (v != btf_enum64_value(enums + i))
4510			continue;
4511
4512		btf_show_type_value(show, "%s",
4513				    __btf_name_by_offset(btf,
4514							 enums[i].name_off));
4515
4516		btf_show_end_type(show);
4517		return;
4518	}
4519
4520	if (btf_type_kflag(t))
4521		btf_show_type_value(show, "%lld", v);
4522	else
4523		btf_show_type_value(show, "%llu", v);
4524	btf_show_end_type(show);
4525}
4526
4527static const struct btf_kind_operations enum64_ops = {
4528	.check_meta = btf_enum64_check_meta,
4529	.resolve = btf_df_resolve,
4530	.check_member = btf_enum_check_member,
4531	.check_kflag_member = btf_enum_check_kflag_member,
4532	.log_details = btf_enum_log,
4533	.show = btf_enum64_show,
4534};
4535
4536static s32 btf_func_proto_check_meta(struct btf_verifier_env *env,
4537				     const struct btf_type *t,
4538				     u32 meta_left)
4539{
4540	u32 meta_needed = btf_type_vlen(t) * sizeof(struct btf_param);
4541
4542	if (meta_left < meta_needed) {
4543		btf_verifier_log_basic(env, t,
4544				       "meta_left:%u meta_needed:%u",
4545				       meta_left, meta_needed);
4546		return -EINVAL;
4547	}
4548
4549	if (t->name_off) {
4550		btf_verifier_log_type(env, t, "Invalid name");
4551		return -EINVAL;
4552	}
4553
4554	if (btf_type_kflag(t)) {
4555		btf_verifier_log_type(env, t, "Invalid btf_info kind_flag");
4556		return -EINVAL;
4557	}
4558
4559	btf_verifier_log_type(env, t, NULL);
4560
4561	return meta_needed;
4562}
4563
4564static void btf_func_proto_log(struct btf_verifier_env *env,
4565			       const struct btf_type *t)
4566{
4567	const struct btf_param *args = (const struct btf_param *)(t + 1);
4568	u16 nr_args = btf_type_vlen(t), i;
4569
4570	btf_verifier_log(env, "return=%u args=(", t->type);
4571	if (!nr_args) {
4572		btf_verifier_log(env, "void");
4573		goto done;
4574	}
4575
4576	if (nr_args == 1 && !args[0].type) {
4577		/* Only one vararg */
4578		btf_verifier_log(env, "vararg");
4579		goto done;
4580	}
4581
4582	btf_verifier_log(env, "%u %s", args[0].type,
4583			 __btf_name_by_offset(env->btf,
4584					      args[0].name_off));
4585	for (i = 1; i < nr_args - 1; i++)
4586		btf_verifier_log(env, ", %u %s", args[i].type,
4587				 __btf_name_by_offset(env->btf,
4588						      args[i].name_off));
4589
4590	if (nr_args > 1) {
4591		const struct btf_param *last_arg = &args[nr_args - 1];
4592
4593		if (last_arg->type)
4594			btf_verifier_log(env, ", %u %s", last_arg->type,
4595					 __btf_name_by_offset(env->btf,
4596							      last_arg->name_off));
4597		else
4598			btf_verifier_log(env, ", vararg");
4599	}
4600
4601done:
4602	btf_verifier_log(env, ")");
4603}
4604
4605static const struct btf_kind_operations func_proto_ops = {
4606	.check_meta = btf_func_proto_check_meta,
4607	.resolve = btf_df_resolve,
4608	/*
4609	 * BTF_KIND_FUNC_PROTO cannot be directly referred by
4610	 * a struct's member.
4611	 *
4612	 * It should be a function pointer instead.
4613	 * (i.e. struct's member -> BTF_KIND_PTR -> BTF_KIND_FUNC_PROTO)
4614	 *
4615	 * Hence, there is no btf_func_check_member().
4616	 */
4617	.check_member = btf_df_check_member,
4618	.check_kflag_member = btf_df_check_kflag_member,
4619	.log_details = btf_func_proto_log,
4620	.show = btf_df_show,
4621};
4622
4623static s32 btf_func_check_meta(struct btf_verifier_env *env,
4624			       const struct btf_type *t,
4625			       u32 meta_left)
4626{
4627	if (!t->name_off ||
4628	    !btf_name_valid_identifier(env->btf, t->name_off)) {
4629		btf_verifier_log_type(env, t, "Invalid name");
4630		return -EINVAL;
4631	}
4632
4633	if (btf_type_vlen(t) > BTF_FUNC_GLOBAL) {
4634		btf_verifier_log_type(env, t, "Invalid func linkage");
4635		return -EINVAL;
4636	}
4637
4638	if (btf_type_kflag(t)) {
4639		btf_verifier_log_type(env, t, "Invalid btf_info kind_flag");
4640		return -EINVAL;
4641	}
4642
4643	btf_verifier_log_type(env, t, NULL);
4644
4645	return 0;
4646}
4647
4648static int btf_func_resolve(struct btf_verifier_env *env,
4649			    const struct resolve_vertex *v)
4650{
4651	const struct btf_type *t = v->t;
4652	u32 next_type_id = t->type;
4653	int err;
4654
4655	err = btf_func_check(env, t);
4656	if (err)
4657		return err;
4658
4659	env_stack_pop_resolved(env, next_type_id, 0);
4660	return 0;
4661}
4662
4663static const struct btf_kind_operations func_ops = {
4664	.check_meta = btf_func_check_meta,
4665	.resolve = btf_func_resolve,
4666	.check_member = btf_df_check_member,
4667	.check_kflag_member = btf_df_check_kflag_member,
4668	.log_details = btf_ref_type_log,
4669	.show = btf_df_show,
4670};
4671
4672static s32 btf_var_check_meta(struct btf_verifier_env *env,
4673			      const struct btf_type *t,
4674			      u32 meta_left)
4675{
4676	const struct btf_var *var;
4677	u32 meta_needed = sizeof(*var);
4678
4679	if (meta_left < meta_needed) {
4680		btf_verifier_log_basic(env, t,
4681				       "meta_left:%u meta_needed:%u",
4682				       meta_left, meta_needed);
4683		return -EINVAL;
4684	}
4685
4686	if (btf_type_vlen(t)) {
4687		btf_verifier_log_type(env, t, "vlen != 0");
4688		return -EINVAL;
4689	}
4690
4691	if (btf_type_kflag(t)) {
4692		btf_verifier_log_type(env, t, "Invalid btf_info kind_flag");
4693		return -EINVAL;
4694	}
4695
4696	if (!t->name_off ||
4697	    !btf_name_valid_identifier(env->btf, t->name_off)) {
4698		btf_verifier_log_type(env, t, "Invalid name");
4699		return -EINVAL;
4700	}
4701
4702	/* A var cannot be in type void */
4703	if (!t->type || !BTF_TYPE_ID_VALID(t->type)) {
4704		btf_verifier_log_type(env, t, "Invalid type_id");
4705		return -EINVAL;
4706	}
4707
4708	var = btf_type_var(t);
4709	if (var->linkage != BTF_VAR_STATIC &&
4710	    var->linkage != BTF_VAR_GLOBAL_ALLOCATED) {
4711		btf_verifier_log_type(env, t, "Linkage not supported");
4712		return -EINVAL;
4713	}
4714
4715	btf_verifier_log_type(env, t, NULL);
4716
4717	return meta_needed;
4718}
4719
4720static void btf_var_log(struct btf_verifier_env *env, const struct btf_type *t)
4721{
4722	const struct btf_var *var = btf_type_var(t);
4723
4724	btf_verifier_log(env, "type_id=%u linkage=%u", t->type, var->linkage);
4725}
4726
4727static const struct btf_kind_operations var_ops = {
4728	.check_meta		= btf_var_check_meta,
4729	.resolve		= btf_var_resolve,
4730	.check_member		= btf_df_check_member,
4731	.check_kflag_member	= btf_df_check_kflag_member,
4732	.log_details		= btf_var_log,
4733	.show			= btf_var_show,
4734};
4735
4736static s32 btf_datasec_check_meta(struct btf_verifier_env *env,
4737				  const struct btf_type *t,
4738				  u32 meta_left)
4739{
4740	const struct btf_var_secinfo *vsi;
4741	u64 last_vsi_end_off = 0, sum = 0;
4742	u32 i, meta_needed;
4743
4744	meta_needed = btf_type_vlen(t) * sizeof(*vsi);
4745	if (meta_left < meta_needed) {
4746		btf_verifier_log_basic(env, t,
4747				       "meta_left:%u meta_needed:%u",
4748				       meta_left, meta_needed);
4749		return -EINVAL;
4750	}
4751
4752	if (!t->size) {
4753		btf_verifier_log_type(env, t, "size == 0");
4754		return -EINVAL;
4755	}
4756
4757	if (btf_type_kflag(t)) {
4758		btf_verifier_log_type(env, t, "Invalid btf_info kind_flag");
4759		return -EINVAL;
4760	}
4761
4762	if (!t->name_off ||
4763	    !btf_name_valid_section(env->btf, t->name_off)) {
4764		btf_verifier_log_type(env, t, "Invalid name");
4765		return -EINVAL;
4766	}
4767
4768	btf_verifier_log_type(env, t, NULL);
4769
4770	for_each_vsi(i, t, vsi) {
4771		/* A var cannot be in type void */
4772		if (!vsi->type || !BTF_TYPE_ID_VALID(vsi->type)) {
4773			btf_verifier_log_vsi(env, t, vsi,
4774					     "Invalid type_id");
4775			return -EINVAL;
4776		}
4777
4778		if (vsi->offset < last_vsi_end_off || vsi->offset >= t->size) {
4779			btf_verifier_log_vsi(env, t, vsi,
4780					     "Invalid offset");
4781			return -EINVAL;
4782		}
4783
4784		if (!vsi->size || vsi->size > t->size) {
4785			btf_verifier_log_vsi(env, t, vsi,
4786					     "Invalid size");
4787			return -EINVAL;
4788		}
4789
4790		last_vsi_end_off = vsi->offset + vsi->size;
4791		if (last_vsi_end_off > t->size) {
4792			btf_verifier_log_vsi(env, t, vsi,
4793					     "Invalid offset+size");
4794			return -EINVAL;
4795		}
4796
4797		btf_verifier_log_vsi(env, t, vsi, NULL);
4798		sum += vsi->size;
4799	}
4800
4801	if (t->size < sum) {
4802		btf_verifier_log_type(env, t, "Invalid btf_info size");
4803		return -EINVAL;
4804	}
4805
4806	return meta_needed;
4807}
4808
4809static int btf_datasec_resolve(struct btf_verifier_env *env,
4810			       const struct resolve_vertex *v)
4811{
4812	const struct btf_var_secinfo *vsi;
4813	struct btf *btf = env->btf;
4814	u16 i;
4815
4816	env->resolve_mode = RESOLVE_TBD;
4817	for_each_vsi_from(i, v->next_member, v->t, vsi) {
4818		u32 var_type_id = vsi->type, type_id, type_size = 0;
4819		const struct btf_type *var_type = btf_type_by_id(env->btf,
4820								 var_type_id);
4821		if (!var_type || !btf_type_is_var(var_type)) {
4822			btf_verifier_log_vsi(env, v->t, vsi,
4823					     "Not a VAR kind member");
4824			return -EINVAL;
4825		}
4826
4827		if (!env_type_is_resolve_sink(env, var_type) &&
4828		    !env_type_is_resolved(env, var_type_id)) {
4829			env_stack_set_next_member(env, i + 1);
4830			return env_stack_push(env, var_type, var_type_id);
4831		}
4832
4833		type_id = var_type->type;
4834		if (!btf_type_id_size(btf, &type_id, &type_size)) {
4835			btf_verifier_log_vsi(env, v->t, vsi, "Invalid type");
4836			return -EINVAL;
4837		}
4838
4839		if (vsi->size < type_size) {
4840			btf_verifier_log_vsi(env, v->t, vsi, "Invalid size");
4841			return -EINVAL;
4842		}
4843	}
4844
4845	env_stack_pop_resolved(env, 0, 0);
4846	return 0;
4847}
4848
4849static void btf_datasec_log(struct btf_verifier_env *env,
4850			    const struct btf_type *t)
4851{
4852	btf_verifier_log(env, "size=%u vlen=%u", t->size, btf_type_vlen(t));
4853}
4854
4855static void btf_datasec_show(const struct btf *btf,
4856			     const struct btf_type *t, u32 type_id,
4857			     void *data, u8 bits_offset,
4858			     struct btf_show *show)
4859{
4860	const struct btf_var_secinfo *vsi;
4861	const struct btf_type *var;
4862	u32 i;
4863
4864	if (!btf_show_start_type(show, t, type_id, data))
4865		return;
4866
4867	btf_show_type_value(show, "section (\"%s\") = {",
4868			    __btf_name_by_offset(btf, t->name_off));
4869	for_each_vsi(i, t, vsi) {
4870		var = btf_type_by_id(btf, vsi->type);
4871		if (i)
4872			btf_show(show, ",");
4873		btf_type_ops(var)->show(btf, var, vsi->type,
4874					data + vsi->offset, bits_offset, show);
4875	}
4876	btf_show_end_type(show);
4877}
4878
4879static const struct btf_kind_operations datasec_ops = {
4880	.check_meta		= btf_datasec_check_meta,
4881	.resolve		= btf_datasec_resolve,
4882	.check_member		= btf_df_check_member,
4883	.check_kflag_member	= btf_df_check_kflag_member,
4884	.log_details		= btf_datasec_log,
4885	.show			= btf_datasec_show,
4886};
4887
4888static s32 btf_float_check_meta(struct btf_verifier_env *env,
4889				const struct btf_type *t,
4890				u32 meta_left)
4891{
4892	if (btf_type_vlen(t)) {
4893		btf_verifier_log_type(env, t, "vlen != 0");
4894		return -EINVAL;
4895	}
4896
4897	if (btf_type_kflag(t)) {
4898		btf_verifier_log_type(env, t, "Invalid btf_info kind_flag");
4899		return -EINVAL;
4900	}
4901
4902	if (t->size != 2 && t->size != 4 && t->size != 8 && t->size != 12 &&
4903	    t->size != 16) {
4904		btf_verifier_log_type(env, t, "Invalid type_size");
4905		return -EINVAL;
4906	}
4907
4908	btf_verifier_log_type(env, t, NULL);
4909
4910	return 0;
4911}
4912
4913static int btf_float_check_member(struct btf_verifier_env *env,
4914				  const struct btf_type *struct_type,
4915				  const struct btf_member *member,
4916				  const struct btf_type *member_type)
4917{
4918	u64 start_offset_bytes;
4919	u64 end_offset_bytes;
4920	u64 misalign_bits;
4921	u64 align_bytes;
4922	u64 align_bits;
4923
4924	/* Different architectures have different alignment requirements, so
4925	 * here we check only for the reasonable minimum. This way we ensure
4926	 * that types after CO-RE can pass the kernel BTF verifier.
4927	 */
4928	align_bytes = min_t(u64, sizeof(void *), member_type->size);
4929	align_bits = align_bytes * BITS_PER_BYTE;
4930	div64_u64_rem(member->offset, align_bits, &misalign_bits);
4931	if (misalign_bits) {
4932		btf_verifier_log_member(env, struct_type, member,
4933					"Member is not properly aligned");
4934		return -EINVAL;
4935	}
4936
4937	start_offset_bytes = member->offset / BITS_PER_BYTE;
4938	end_offset_bytes = start_offset_bytes + member_type->size;
4939	if (end_offset_bytes > struct_type->size) {
4940		btf_verifier_log_member(env, struct_type, member,
4941					"Member exceeds struct_size");
4942		return -EINVAL;
4943	}
4944
4945	return 0;
4946}
4947
4948static void btf_float_log(struct btf_verifier_env *env,
4949			  const struct btf_type *t)
4950{
4951	btf_verifier_log(env, "size=%u", t->size);
4952}
4953
4954static const struct btf_kind_operations float_ops = {
4955	.check_meta = btf_float_check_meta,
4956	.resolve = btf_df_resolve,
4957	.check_member = btf_float_check_member,
4958	.check_kflag_member = btf_generic_check_kflag_member,
4959	.log_details = btf_float_log,
4960	.show = btf_df_show,
4961};
4962
4963static s32 btf_decl_tag_check_meta(struct btf_verifier_env *env,
4964			      const struct btf_type *t,
4965			      u32 meta_left)
4966{
4967	const struct btf_decl_tag *tag;
4968	u32 meta_needed = sizeof(*tag);
4969	s32 component_idx;
4970	const char *value;
4971
4972	if (meta_left < meta_needed) {
4973		btf_verifier_log_basic(env, t,
4974				       "meta_left:%u meta_needed:%u",
4975				       meta_left, meta_needed);
4976		return -EINVAL;
4977	}
4978
4979	value = btf_name_by_offset(env->btf, t->name_off);
4980	if (!value || !value[0]) {
4981		btf_verifier_log_type(env, t, "Invalid value");
4982		return -EINVAL;
4983	}
4984
4985	if (btf_type_vlen(t)) {
4986		btf_verifier_log_type(env, t, "vlen != 0");
4987		return -EINVAL;
4988	}
4989
4990	component_idx = btf_type_decl_tag(t)->component_idx;
4991	if (component_idx < -1) {
4992		btf_verifier_log_type(env, t, "Invalid component_idx");
4993		return -EINVAL;
4994	}
4995
4996	btf_verifier_log_type(env, t, NULL);
4997
4998	return meta_needed;
4999}
5000
5001static int btf_decl_tag_resolve(struct btf_verifier_env *env,
5002			   const struct resolve_vertex *v)
5003{
5004	const struct btf_type *next_type;
5005	const struct btf_type *t = v->t;
5006	u32 next_type_id = t->type;
5007	struct btf *btf = env->btf;
5008	s32 component_idx;
5009	u32 vlen;
5010
5011	next_type = btf_type_by_id(btf, next_type_id);
5012	if (!next_type || !btf_type_is_decl_tag_target(next_type)) {
5013		btf_verifier_log_type(env, v->t, "Invalid type_id");
5014		return -EINVAL;
5015	}
5016
5017	if (!env_type_is_resolve_sink(env, next_type) &&
5018	    !env_type_is_resolved(env, next_type_id))
5019		return env_stack_push(env, next_type, next_type_id);
5020
5021	component_idx = btf_type_decl_tag(t)->component_idx;
5022	if (component_idx != -1) {
5023		if (btf_type_is_var(next_type) || btf_type_is_typedef(next_type)) {
5024			btf_verifier_log_type(env, v->t, "Invalid component_idx");
5025			return -EINVAL;
5026		}
5027
5028		if (btf_type_is_struct(next_type)) {
5029			vlen = btf_type_vlen(next_type);
5030		} else {
5031			/* next_type should be a function */
5032			next_type = btf_type_by_id(btf, next_type->type);
5033			vlen = btf_type_vlen(next_type);
5034		}
5035
5036		if ((u32)component_idx >= vlen) {
5037			btf_verifier_log_type(env, v->t, "Invalid component_idx");
5038			return -EINVAL;
5039		}
5040	}
5041
5042	env_stack_pop_resolved(env, next_type_id, 0);
5043
5044	return 0;
5045}
5046
5047static void btf_decl_tag_log(struct btf_verifier_env *env, const struct btf_type *t)
5048{
5049	btf_verifier_log(env, "type=%u component_idx=%d", t->type,
5050			 btf_type_decl_tag(t)->component_idx);
5051}
5052
5053static const struct btf_kind_operations decl_tag_ops = {
5054	.check_meta = btf_decl_tag_check_meta,
5055	.resolve = btf_decl_tag_resolve,
5056	.check_member = btf_df_check_member,
5057	.check_kflag_member = btf_df_check_kflag_member,
5058	.log_details = btf_decl_tag_log,
5059	.show = btf_df_show,
5060};
5061
5062static int btf_func_proto_check(struct btf_verifier_env *env,
5063				const struct btf_type *t)
5064{
5065	const struct btf_type *ret_type;
5066	const struct btf_param *args;
5067	const struct btf *btf;
5068	u16 nr_args, i;
5069	int err;
5070
5071	btf = env->btf;
5072	args = (const struct btf_param *)(t + 1);
5073	nr_args = btf_type_vlen(t);
5074
5075	/* Check func return type which could be "void" (t->type == 0) */
5076	if (t->type) {
5077		u32 ret_type_id = t->type;
5078
5079		ret_type = btf_type_by_id(btf, ret_type_id);
5080		if (!ret_type) {
5081			btf_verifier_log_type(env, t, "Invalid return type");
5082			return -EINVAL;
5083		}
5084
5085		if (btf_type_is_resolve_source_only(ret_type)) {
5086			btf_verifier_log_type(env, t, "Invalid return type");
5087			return -EINVAL;
5088		}
5089
5090		if (btf_type_needs_resolve(ret_type) &&
5091		    !env_type_is_resolved(env, ret_type_id)) {
5092			err = btf_resolve(env, ret_type, ret_type_id);
5093			if (err)
5094				return err;
5095		}
5096
5097		/* Ensure the return type is a type that has a size */
5098		if (!btf_type_id_size(btf, &ret_type_id, NULL)) {
5099			btf_verifier_log_type(env, t, "Invalid return type");
5100			return -EINVAL;
5101		}
5102	}
5103
5104	if (!nr_args)
5105		return 0;
5106
5107	/* Last func arg type_id could be 0 if it is a vararg */
5108	if (!args[nr_args - 1].type) {
5109		if (args[nr_args - 1].name_off) {
5110			btf_verifier_log_type(env, t, "Invalid arg#%u",
5111					      nr_args);
5112			return -EINVAL;
5113		}
5114		nr_args--;
5115	}
5116
5117	for (i = 0; i < nr_args; i++) {
5118		const struct btf_type *arg_type;
5119		u32 arg_type_id;
5120
5121		arg_type_id = args[i].type;
5122		arg_type = btf_type_by_id(btf, arg_type_id);
5123		if (!arg_type) {
5124			btf_verifier_log_type(env, t, "Invalid arg#%u", i + 1);
5125			return -EINVAL;
5126		}
5127
5128		if (btf_type_is_resolve_source_only(arg_type)) {
5129			btf_verifier_log_type(env, t, "Invalid arg#%u", i + 1);
5130			return -EINVAL;
5131		}
5132
5133		if (args[i].name_off &&
5134		    (!btf_name_offset_valid(btf, args[i].name_off) ||
5135		     !btf_name_valid_identifier(btf, args[i].name_off))) {
5136			btf_verifier_log_type(env, t,
5137					      "Invalid arg#%u", i + 1);
5138			return -EINVAL;
5139		}
5140
5141		if (btf_type_needs_resolve(arg_type) &&
5142		    !env_type_is_resolved(env, arg_type_id)) {
5143			err = btf_resolve(env, arg_type, arg_type_id);
5144			if (err)
5145				return err;
5146		}
5147
5148		if (!btf_type_id_size(btf, &arg_type_id, NULL)) {
5149			btf_verifier_log_type(env, t, "Invalid arg#%u", i + 1);
5150			return -EINVAL;
5151		}
5152	}
5153
5154	return 0;
5155}
5156
5157static int btf_func_check(struct btf_verifier_env *env,
5158			  const struct btf_type *t)
5159{
5160	const struct btf_type *proto_type;
5161	const struct btf_param *args;
5162	const struct btf *btf;
5163	u16 nr_args, i;
5164
5165	btf = env->btf;
5166	proto_type = btf_type_by_id(btf, t->type);
5167
5168	if (!proto_type || !btf_type_is_func_proto(proto_type)) {
5169		btf_verifier_log_type(env, t, "Invalid type_id");
5170		return -EINVAL;
5171	}
5172
5173	args = (const struct btf_param *)(proto_type + 1);
5174	nr_args = btf_type_vlen(proto_type);
5175	for (i = 0; i < nr_args; i++) {
5176		if (!args[i].name_off && args[i].type) {
5177			btf_verifier_log_type(env, t, "Invalid arg#%u", i + 1);
5178			return -EINVAL;
5179		}
5180	}
5181
5182	return 0;
5183}
5184
5185static const struct btf_kind_operations * const kind_ops[NR_BTF_KINDS] = {
5186	[BTF_KIND_INT] = &int_ops,
5187	[BTF_KIND_PTR] = &ptr_ops,
5188	[BTF_KIND_ARRAY] = &array_ops,
5189	[BTF_KIND_STRUCT] = &struct_ops,
5190	[BTF_KIND_UNION] = &struct_ops,
5191	[BTF_KIND_ENUM] = &enum_ops,
5192	[BTF_KIND_FWD] = &fwd_ops,
5193	[BTF_KIND_TYPEDEF] = &modifier_ops,
5194	[BTF_KIND_VOLATILE] = &modifier_ops,
5195	[BTF_KIND_CONST] = &modifier_ops,
5196	[BTF_KIND_RESTRICT] = &modifier_ops,
5197	[BTF_KIND_FUNC] = &func_ops,
5198	[BTF_KIND_FUNC_PROTO] = &func_proto_ops,
5199	[BTF_KIND_VAR] = &var_ops,
5200	[BTF_KIND_DATASEC] = &datasec_ops,
5201	[BTF_KIND_FLOAT] = &float_ops,
5202	[BTF_KIND_DECL_TAG] = &decl_tag_ops,
5203	[BTF_KIND_TYPE_TAG] = &modifier_ops,
5204	[BTF_KIND_ENUM64] = &enum64_ops,
5205};
5206
5207static s32 btf_check_meta(struct btf_verifier_env *env,
5208			  const struct btf_type *t,
5209			  u32 meta_left)
5210{
5211	u32 saved_meta_left = meta_left;
5212	s32 var_meta_size;
5213
5214	if (meta_left < sizeof(*t)) {
5215		btf_verifier_log(env, "[%u] meta_left:%u meta_needed:%zu",
5216				 env->log_type_id, meta_left, sizeof(*t));
5217		return -EINVAL;
5218	}
5219	meta_left -= sizeof(*t);
5220
5221	if (t->info & ~BTF_INFO_MASK) {
5222		btf_verifier_log(env, "[%u] Invalid btf_info:%x",
5223				 env->log_type_id, t->info);
5224		return -EINVAL;
5225	}
5226
5227	if (BTF_INFO_KIND(t->info) > BTF_KIND_MAX ||
5228	    BTF_INFO_KIND(t->info) == BTF_KIND_UNKN) {
5229		btf_verifier_log(env, "[%u] Invalid kind:%u",
5230				 env->log_type_id, BTF_INFO_KIND(t->info));
5231		return -EINVAL;
5232	}
5233
5234	if (!btf_name_offset_valid(env->btf, t->name_off)) {
5235		btf_verifier_log(env, "[%u] Invalid name_offset:%u",
5236				 env->log_type_id, t->name_off);
5237		return -EINVAL;
5238	}
5239
5240	var_meta_size = btf_type_ops(t)->check_meta(env, t, meta_left);
5241	if (var_meta_size < 0)
5242		return var_meta_size;
5243
5244	meta_left -= var_meta_size;
5245
5246	return saved_meta_left - meta_left;
5247}
5248
5249static int btf_check_all_metas(struct btf_verifier_env *env)
5250{
5251	struct btf *btf = env->btf;
5252	struct btf_header *hdr;
5253	void *cur, *end;
5254
5255	hdr = &btf->hdr;
5256	cur = btf->nohdr_data + hdr->type_off;
5257	end = cur + hdr->type_len;
5258
5259	env->log_type_id = btf->base_btf ? btf->start_id : 1;
5260	while (cur < end) {
5261		struct btf_type *t = cur;
5262		s32 meta_size;
5263
5264		meta_size = btf_check_meta(env, t, end - cur);
5265		if (meta_size < 0)
5266			return meta_size;
5267
5268		btf_add_type(env, t);
5269		cur += meta_size;
5270		env->log_type_id++;
5271	}
5272
5273	return 0;
5274}
5275
5276static bool btf_resolve_valid(struct btf_verifier_env *env,
5277			      const struct btf_type *t,
5278			      u32 type_id)
5279{
5280	struct btf *btf = env->btf;
5281
5282	if (!env_type_is_resolved(env, type_id))
5283		return false;
5284
5285	if (btf_type_is_struct(t) || btf_type_is_datasec(t))
5286		return !btf_resolved_type_id(btf, type_id) &&
5287		       !btf_resolved_type_size(btf, type_id);
5288
5289	if (btf_type_is_decl_tag(t) || btf_type_is_func(t))
5290		return btf_resolved_type_id(btf, type_id) &&
5291		       !btf_resolved_type_size(btf, type_id);
5292
5293	if (btf_type_is_modifier(t) || btf_type_is_ptr(t) ||
5294	    btf_type_is_var(t)) {
5295		t = btf_type_id_resolve(btf, &type_id);
5296		return t &&
5297		       !btf_type_is_modifier(t) &&
5298		       !btf_type_is_var(t) &&
5299		       !btf_type_is_datasec(t);
5300	}
5301
5302	if (btf_type_is_array(t)) {
5303		const struct btf_array *array = btf_type_array(t);
5304		const struct btf_type *elem_type;
5305		u32 elem_type_id = array->type;
5306		u32 elem_size;
5307
5308		elem_type = btf_type_id_size(btf, &elem_type_id, &elem_size);
5309		return elem_type && !btf_type_is_modifier(elem_type) &&
5310			(array->nelems * elem_size ==
5311			 btf_resolved_type_size(btf, type_id));
5312	}
5313
5314	return false;
5315}
5316
5317static int btf_resolve(struct btf_verifier_env *env,
5318		       const struct btf_type *t, u32 type_id)
5319{
5320	u32 save_log_type_id = env->log_type_id;
5321	const struct resolve_vertex *v;
5322	int err = 0;
5323
5324	env->resolve_mode = RESOLVE_TBD;
5325	env_stack_push(env, t, type_id);
5326	while (!err && (v = env_stack_peak(env))) {
5327		env->log_type_id = v->type_id;
5328		err = btf_type_ops(v->t)->resolve(env, v);
5329	}
5330
5331	env->log_type_id = type_id;
5332	if (err == -E2BIG) {
5333		btf_verifier_log_type(env, t,
5334				      "Exceeded max resolving depth:%u",
5335				      MAX_RESOLVE_DEPTH);
5336	} else if (err == -EEXIST) {
5337		btf_verifier_log_type(env, t, "Loop detected");
5338	}
5339
5340	/* Final sanity check */
5341	if (!err && !btf_resolve_valid(env, t, type_id)) {
5342		btf_verifier_log_type(env, t, "Invalid resolve state");
5343		err = -EINVAL;
5344	}
5345
5346	env->log_type_id = save_log_type_id;
5347	return err;
5348}
5349
5350static int btf_check_all_types(struct btf_verifier_env *env)
5351{
5352	struct btf *btf = env->btf;
5353	const struct btf_type *t;
5354	u32 type_id, i;
5355	int err;
5356
5357	err = env_resolve_init(env);
5358	if (err)
5359		return err;
5360
5361	env->phase++;
5362	for (i = btf->base_btf ? 0 : 1; i < btf->nr_types; i++) {
5363		type_id = btf->start_id + i;
5364		t = btf_type_by_id(btf, type_id);
5365
5366		env->log_type_id = type_id;
5367		if (btf_type_needs_resolve(t) &&
5368		    !env_type_is_resolved(env, type_id)) {
5369			err = btf_resolve(env, t, type_id);
5370			if (err)
5371				return err;
5372		}
5373
5374		if (btf_type_is_func_proto(t)) {
5375			err = btf_func_proto_check(env, t);
5376			if (err)
5377				return err;
5378		}
5379	}
5380
5381	return 0;
5382}
5383
5384static int btf_parse_type_sec(struct btf_verifier_env *env)
5385{
5386	const struct btf_header *hdr = &env->btf->hdr;
5387	int err;
5388
5389	/* Type section must align to 4 bytes */
5390	if (hdr->type_off & (sizeof(u32) - 1)) {
5391		btf_verifier_log(env, "Unaligned type_off");
5392		return -EINVAL;
5393	}
5394
5395	if (!env->btf->base_btf && !hdr->type_len) {
5396		btf_verifier_log(env, "No type found");
5397		return -EINVAL;
5398	}
5399
5400	err = btf_check_all_metas(env);
5401	if (err)
5402		return err;
5403
5404	return btf_check_all_types(env);
5405}
5406
5407static int btf_parse_str_sec(struct btf_verifier_env *env)
5408{
5409	const struct btf_header *hdr;
5410	struct btf *btf = env->btf;
5411	const char *start, *end;
5412
5413	hdr = &btf->hdr;
5414	start = btf->nohdr_data + hdr->str_off;
5415	end = start + hdr->str_len;
5416
5417	if (end != btf->data + btf->data_size) {
5418		btf_verifier_log(env, "String section is not at the end");
5419		return -EINVAL;
5420	}
5421
5422	btf->strings = start;
5423
5424	if (btf->base_btf && !hdr->str_len)
5425		return 0;
5426	if (!hdr->str_len || hdr->str_len - 1 > BTF_MAX_NAME_OFFSET || end[-1]) {
5427		btf_verifier_log(env, "Invalid string section");
5428		return -EINVAL;
5429	}
5430	if (!btf->base_btf && start[0]) {
5431		btf_verifier_log(env, "Invalid string section");
5432		return -EINVAL;
5433	}
5434
5435	return 0;
5436}
5437
5438static const size_t btf_sec_info_offset[] = {
5439	offsetof(struct btf_header, type_off),
5440	offsetof(struct btf_header, str_off),
5441};
5442
5443static int btf_sec_info_cmp(const void *a, const void *b)
5444{
5445	const struct btf_sec_info *x = a;
5446	const struct btf_sec_info *y = b;
5447
5448	return (int)(x->off - y->off) ? : (int)(x->len - y->len);
5449}
5450
5451static int btf_check_sec_info(struct btf_verifier_env *env,
5452			      u32 btf_data_size)
5453{
5454	struct btf_sec_info secs[ARRAY_SIZE(btf_sec_info_offset)];
5455	u32 total, expected_total, i;
5456	const struct btf_header *hdr;
5457	const struct btf *btf;
5458
5459	btf = env->btf;
5460	hdr = &btf->hdr;
5461
5462	/* Populate the secs from hdr */
5463	for (i = 0; i < ARRAY_SIZE(btf_sec_info_offset); i++)
5464		secs[i] = *(struct btf_sec_info *)((void *)hdr +
5465						   btf_sec_info_offset[i]);
5466
5467	sort(secs, ARRAY_SIZE(btf_sec_info_offset),
5468	     sizeof(struct btf_sec_info), btf_sec_info_cmp, NULL);
5469
5470	/* Check for gaps and overlap among sections */
5471	total = 0;
5472	expected_total = btf_data_size - hdr->hdr_len;
5473	for (i = 0; i < ARRAY_SIZE(btf_sec_info_offset); i++) {
5474		if (expected_total < secs[i].off) {
5475			btf_verifier_log(env, "Invalid section offset");
5476			return -EINVAL;
5477		}
5478		if (total < secs[i].off) {
5479			/* gap */
5480			btf_verifier_log(env, "Unsupported section found");
5481			return -EINVAL;
5482		}
5483		if (total > secs[i].off) {
5484			btf_verifier_log(env, "Section overlap found");
5485			return -EINVAL;
5486		}
5487		if (expected_total - total < secs[i].len) {
5488			btf_verifier_log(env,
5489					 "Total section length too long");
5490			return -EINVAL;
5491		}
5492		total += secs[i].len;
5493	}
5494
5495	/* There is data other than hdr and known sections */
5496	if (expected_total != total) {
5497		btf_verifier_log(env, "Unsupported section found");
5498		return -EINVAL;
5499	}
5500
5501	return 0;
5502}
5503
5504static int btf_parse_hdr(struct btf_verifier_env *env)
5505{
5506	u32 hdr_len, hdr_copy, btf_data_size;
5507	const struct btf_header *hdr;
5508	struct btf *btf;
5509
5510	btf = env->btf;
5511	btf_data_size = btf->data_size;
5512
5513	if (btf_data_size < offsetofend(struct btf_header, hdr_len)) {
5514		btf_verifier_log(env, "hdr_len not found");
5515		return -EINVAL;
5516	}
5517
5518	hdr = btf->data;
5519	hdr_len = hdr->hdr_len;
5520	if (btf_data_size < hdr_len) {
5521		btf_verifier_log(env, "btf_header not found");
5522		return -EINVAL;
5523	}
5524
5525	/* Ensure the unsupported header fields are zero */
5526	if (hdr_len > sizeof(btf->hdr)) {
5527		u8 *expected_zero = btf->data + sizeof(btf->hdr);
5528		u8 *end = btf->data + hdr_len;
5529
5530		for (; expected_zero < end; expected_zero++) {
5531			if (*expected_zero) {
5532				btf_verifier_log(env, "Unsupported btf_header");
5533				return -E2BIG;
5534			}
5535		}
5536	}
5537
5538	hdr_copy = min_t(u32, hdr_len, sizeof(btf->hdr));
5539	memcpy(&btf->hdr, btf->data, hdr_copy);
5540
5541	hdr = &btf->hdr;
5542
5543	btf_verifier_log_hdr(env, btf_data_size);
5544
5545	if (hdr->magic != BTF_MAGIC) {
5546		btf_verifier_log(env, "Invalid magic");
5547		return -EINVAL;
5548	}
5549
5550	if (hdr->version != BTF_VERSION) {
5551		btf_verifier_log(env, "Unsupported version");
5552		return -ENOTSUPP;
5553	}
5554
5555	if (hdr->flags) {
5556		btf_verifier_log(env, "Unsupported flags");
5557		return -ENOTSUPP;
5558	}
5559
5560	if (!btf->base_btf && btf_data_size == hdr->hdr_len) {
5561		btf_verifier_log(env, "No data");
5562		return -EINVAL;
5563	}
5564
5565	return btf_check_sec_info(env, btf_data_size);
5566}
5567
5568static const char *alloc_obj_fields[] = {
5569	"bpf_spin_lock",
5570	"bpf_list_head",
5571	"bpf_list_node",
5572	"bpf_rb_root",
5573	"bpf_rb_node",
5574	"bpf_refcount",
5575};
5576
5577static struct btf_struct_metas *
5578btf_parse_struct_metas(struct bpf_verifier_log *log, struct btf *btf)
5579{
5580	struct btf_struct_metas *tab = NULL;
5581	struct btf_id_set *aof;
5582	int i, n, id, ret;
5583
5584	BUILD_BUG_ON(offsetof(struct btf_id_set, cnt) != 0);
5585	BUILD_BUG_ON(sizeof(struct btf_id_set) != sizeof(u32));
5586
5587	aof = kmalloc(sizeof(*aof), GFP_KERNEL | __GFP_NOWARN);
5588	if (!aof)
5589		return ERR_PTR(-ENOMEM);
5590	aof->cnt = 0;
5591
5592	for (i = 0; i < ARRAY_SIZE(alloc_obj_fields); i++) {
5593		/* Try to find whether this special type exists in user BTF, and
5594		 * if so remember its ID so we can easily find it among members
5595		 * of structs that we iterate in the next loop.
5596		 */
5597		struct btf_id_set *new_aof;
5598
5599		id = btf_find_by_name_kind(btf, alloc_obj_fields[i], BTF_KIND_STRUCT);
5600		if (id < 0)
5601			continue;
5602
5603		new_aof = krealloc(aof, struct_size(new_aof, ids, aof->cnt + 1),
5604				   GFP_KERNEL | __GFP_NOWARN);
5605		if (!new_aof) {
5606			ret = -ENOMEM;
5607			goto free_aof;
5608		}
5609		aof = new_aof;
5610		aof->ids[aof->cnt++] = id;
5611	}
5612
5613	n = btf_nr_types(btf);
5614	for (i = 1; i < n; i++) {
5615		/* Try to find if there are kptrs in user BTF and remember their ID */
5616		struct btf_id_set *new_aof;
5617		struct btf_field_info tmp;
5618		const struct btf_type *t;
5619
5620		t = btf_type_by_id(btf, i);
5621		if (!t) {
5622			ret = -EINVAL;
5623			goto free_aof;
5624		}
5625
5626		ret = btf_find_kptr(btf, t, 0, 0, &tmp, BPF_KPTR);
5627		if (ret != BTF_FIELD_FOUND)
5628			continue;
5629
5630		new_aof = krealloc(aof, struct_size(new_aof, ids, aof->cnt + 1),
5631				   GFP_KERNEL | __GFP_NOWARN);
5632		if (!new_aof) {
5633			ret = -ENOMEM;
5634			goto free_aof;
5635		}
5636		aof = new_aof;
5637		aof->ids[aof->cnt++] = i;
5638	}
5639
5640	if (!aof->cnt) {
5641		kfree(aof);
5642		return NULL;
5643	}
5644	sort(&aof->ids, aof->cnt, sizeof(aof->ids[0]), btf_id_cmp_func, NULL);
5645
5646	for (i = 1; i < n; i++) {
5647		struct btf_struct_metas *new_tab;
5648		const struct btf_member *member;
5649		struct btf_struct_meta *type;
5650		struct btf_record *record;
5651		const struct btf_type *t;
5652		int j, tab_cnt;
5653
5654		t = btf_type_by_id(btf, i);
5655		if (!__btf_type_is_struct(t))
5656			continue;
5657
5658		cond_resched();
5659
5660		for_each_member(j, t, member) {
5661			if (btf_id_set_contains(aof, member->type))
5662				goto parse;
5663		}
5664		continue;
5665	parse:
5666		tab_cnt = tab ? tab->cnt : 0;
5667		new_tab = krealloc(tab, struct_size(new_tab, types, tab_cnt + 1),
5668				   GFP_KERNEL | __GFP_NOWARN);
5669		if (!new_tab) {
5670			ret = -ENOMEM;
5671			goto free;
5672		}
5673		if (!tab)
5674			new_tab->cnt = 0;
5675		tab = new_tab;
5676
5677		type = &tab->types[tab->cnt];
5678		type->btf_id = i;
5679		record = btf_parse_fields(btf, t, BPF_SPIN_LOCK | BPF_RES_SPIN_LOCK | BPF_LIST_HEAD | BPF_LIST_NODE |
5680						  BPF_RB_ROOT | BPF_RB_NODE | BPF_REFCOUNT |
5681						  BPF_KPTR, t->size);
5682		/* The record cannot be unset, treat it as an error if so */
5683		if (IS_ERR_OR_NULL(record)) {
5684			ret = PTR_ERR_OR_ZERO(record) ?: -EFAULT;
5685			goto free;
5686		}
5687		type->record = record;
5688		tab->cnt++;
5689	}
5690	kfree(aof);
5691	return tab;
5692free:
5693	btf_struct_metas_free(tab);
5694free_aof:
5695	kfree(aof);
5696	return ERR_PTR(ret);
5697}
5698
5699struct btf_struct_meta *btf_find_struct_meta(const struct btf *btf, u32 btf_id)
5700{
5701	struct btf_struct_metas *tab;
5702
5703	BUILD_BUG_ON(offsetof(struct btf_struct_meta, btf_id) != 0);
5704	tab = btf->struct_meta_tab;
5705	if (!tab)
5706		return NULL;
5707	return bsearch(&btf_id, tab->types, tab->cnt, sizeof(tab->types[0]), btf_id_cmp_func);
5708}
5709
5710static int btf_check_type_tags(struct btf_verifier_env *env,
5711			       struct btf *btf, int start_id)
5712{
5713	int i, n, good_id = start_id - 1;
5714	bool in_tags;
5715
5716	n = btf_nr_types(btf);
5717	for (i = start_id; i < n; i++) {
5718		const struct btf_type *t;
5719		int chain_limit = 32;
5720		u32 cur_id = i;
5721
5722		t = btf_type_by_id(btf, i);
5723		if (!t)
5724			return -EINVAL;
5725		if (!btf_type_is_modifier(t))
5726			continue;
5727
5728		cond_resched();
5729
5730		in_tags = btf_type_is_type_tag(t);
5731		while (btf_type_is_modifier(t)) {
5732			if (!chain_limit--) {
5733				btf_verifier_log(env, "Max chain length or cycle detected");
5734				return -ELOOP;
5735			}
5736			if (btf_type_is_type_tag(t)) {
5737				if (!in_tags) {
5738					btf_verifier_log(env, "Type tags don't precede modifiers");
5739					return -EINVAL;
5740				}
5741			} else if (in_tags) {
5742				in_tags = false;
5743			}
5744			if (cur_id <= good_id)
5745				break;
5746			/* Move to next type */
5747			cur_id = t->type;
5748			t = btf_type_by_id(btf, cur_id);
5749			if (!t)
5750				return -EINVAL;
5751		}
5752		good_id = i;
5753	}
5754	return 0;
5755}
5756
5757static int finalize_log(struct bpf_verifier_log *log, bpfptr_t uattr, u32 uattr_size)
5758{
5759	u32 log_true_size;
5760	int err;
5761
5762	err = bpf_vlog_finalize(log, &log_true_size);
5763
5764	if (uattr_size >= offsetofend(union bpf_attr, btf_log_true_size) &&
5765	    copy_to_bpfptr_offset(uattr, offsetof(union bpf_attr, btf_log_true_size),
5766				  &log_true_size, sizeof(log_true_size)))
5767		err = -EFAULT;
5768
5769	return err;
5770}
5771
5772static struct btf *btf_parse(const union bpf_attr *attr, bpfptr_t uattr, u32 uattr_size)
5773{
5774	bpfptr_t btf_data = make_bpfptr(attr->btf, uattr.is_kernel);
5775	char __user *log_ubuf = u64_to_user_ptr(attr->btf_log_buf);
5776	struct btf_struct_metas *struct_meta_tab;
5777	struct btf_verifier_env *env = NULL;
5778	struct btf *btf = NULL;
5779	u8 *data;
5780	int err, ret;
5781
5782	if (attr->btf_size > BTF_MAX_SIZE)
5783		return ERR_PTR(-E2BIG);
5784
5785	env = kzalloc(sizeof(*env), GFP_KERNEL | __GFP_NOWARN);
5786	if (!env)
5787		return ERR_PTR(-ENOMEM);
5788
5789	/* user could have requested verbose verifier output
5790	 * and supplied buffer to store the verification trace
5791	 */
5792	err = bpf_vlog_init(&env->log, attr->btf_log_level,
5793			    log_ubuf, attr->btf_log_size);
5794	if (err)
5795		goto errout_free;
5796
5797	btf = kzalloc(sizeof(*btf), GFP_KERNEL | __GFP_NOWARN);
5798	if (!btf) {
5799		err = -ENOMEM;
5800		goto errout;
5801	}
5802	env->btf = btf;
5803
5804	data = kvmalloc(attr->btf_size, GFP_KERNEL | __GFP_NOWARN);
5805	if (!data) {
5806		err = -ENOMEM;
5807		goto errout;
5808	}
5809
5810	btf->data = data;
5811	btf->data_size = attr->btf_size;
5812
5813	if (copy_from_bpfptr(data, btf_data, attr->btf_size)) {
5814		err = -EFAULT;
5815		goto errout;
5816	}
5817
5818	err = btf_parse_hdr(env);
5819	if (err)
5820		goto errout;
5821
5822	btf->nohdr_data = btf->data + btf->hdr.hdr_len;
5823
5824	err = btf_parse_str_sec(env);
5825	if (err)
5826		goto errout;
5827
5828	err = btf_parse_type_sec(env);
5829	if (err)
5830		goto errout;
5831
5832	err = btf_check_type_tags(env, btf, 1);
5833	if (err)
5834		goto errout;
5835
5836	struct_meta_tab = btf_parse_struct_metas(&env->log, btf);
5837	if (IS_ERR(struct_meta_tab)) {
5838		err = PTR_ERR(struct_meta_tab);
5839		goto errout;
5840	}
5841	btf->struct_meta_tab = struct_meta_tab;
5842
5843	if (struct_meta_tab) {
5844		int i;
5845
5846		for (i = 0; i < struct_meta_tab->cnt; i++) {
5847			err = btf_check_and_fixup_fields(btf, struct_meta_tab->types[i].record);
5848			if (err < 0)
5849				goto errout_meta;
5850		}
5851	}
5852
5853	err = finalize_log(&env->log, uattr, uattr_size);
5854	if (err)
5855		goto errout_free;
5856
5857	btf_verifier_env_free(env);
5858	refcount_set(&btf->refcnt, 1);
5859	return btf;
5860
5861errout_meta:
5862	btf_free_struct_meta_tab(btf);
5863errout:
5864	/* overwrite err with -ENOSPC or -EFAULT */
5865	ret = finalize_log(&env->log, uattr, uattr_size);
5866	if (ret)
5867		err = ret;
5868errout_free:
5869	btf_verifier_env_free(env);
5870	if (btf)
5871		btf_free(btf);
5872	return ERR_PTR(err);
5873}
5874
5875extern char __start_BTF[];
5876extern char __stop_BTF[];
5877extern struct btf *btf_vmlinux;
5878
5879#define BPF_MAP_TYPE(_id, _ops)
5880#define BPF_LINK_TYPE(_id, _name)
5881static union {
5882	struct bpf_ctx_convert {
5883#define BPF_PROG_TYPE(_id, _name, prog_ctx_type, kern_ctx_type) \
5884	prog_ctx_type _id##_prog; \
5885	kern_ctx_type _id##_kern;
5886#include <linux/bpf_types.h>
5887#undef BPF_PROG_TYPE
5888	} *__t;
5889	/* 't' is written once under lock. Read many times. */
5890	const struct btf_type *t;
5891} bpf_ctx_convert;
5892enum {
5893#define BPF_PROG_TYPE(_id, _name, prog_ctx_type, kern_ctx_type) \
5894	__ctx_convert##_id,
5895#include <linux/bpf_types.h>
5896#undef BPF_PROG_TYPE
5897	__ctx_convert_unused, /* to avoid empty enum in extreme .config */
5898};
5899static u8 bpf_ctx_convert_map[] = {
5900#define BPF_PROG_TYPE(_id, _name, prog_ctx_type, kern_ctx_type) \
5901	[_id] = __ctx_convert##_id,
5902#include <linux/bpf_types.h>
5903#undef BPF_PROG_TYPE
5904	0, /* avoid empty array */
5905};
5906#undef BPF_MAP_TYPE
5907#undef BPF_LINK_TYPE
5908
5909static const struct btf_type *find_canonical_prog_ctx_type(enum bpf_prog_type prog_type)
5910{
5911	const struct btf_type *conv_struct;
5912	const struct btf_member *ctx_type;
5913
5914	conv_struct = bpf_ctx_convert.t;
5915	if (!conv_struct)
5916		return NULL;
5917	/* prog_type is valid bpf program type. No need for bounds check. */
5918	ctx_type = btf_type_member(conv_struct) + bpf_ctx_convert_map[prog_type] * 2;
5919	/* ctx_type is a pointer to prog_ctx_type in vmlinux.
5920	 * Like 'struct __sk_buff'
5921	 */
5922	return btf_type_by_id(btf_vmlinux, ctx_type->type);
5923}
5924
5925static int find_kern_ctx_type_id(enum bpf_prog_type prog_type)
5926{
5927	const struct btf_type *conv_struct;
5928	const struct btf_member *ctx_type;
5929
5930	conv_struct = bpf_ctx_convert.t;
5931	if (!conv_struct)
5932		return -EFAULT;
5933	/* prog_type is valid bpf program type. No need for bounds check. */
5934	ctx_type = btf_type_member(conv_struct) + bpf_ctx_convert_map[prog_type] * 2 + 1;
5935	/* ctx_type is a pointer to prog_ctx_type in vmlinux.
5936	 * Like 'struct sk_buff'
5937	 */
5938	return ctx_type->type;
5939}
5940
5941bool btf_is_projection_of(const char *pname, const char *tname)
5942{
5943	if (strcmp(pname, "__sk_buff") == 0 && strcmp(tname, "sk_buff") == 0)
5944		return true;
5945	if (strcmp(pname, "xdp_md") == 0 && strcmp(tname, "xdp_buff") == 0)
5946		return true;
5947	return false;
5948}
5949
5950bool btf_is_prog_ctx_type(struct bpf_verifier_log *log, const struct btf *btf,
5951			  const struct btf_type *t, enum bpf_prog_type prog_type,
5952			  int arg)
5953{
5954	const struct btf_type *ctx_type;
5955	const char *tname, *ctx_tname;
5956
5957	t = btf_type_by_id(btf, t->type);
5958
5959	/* KPROBE programs allow bpf_user_pt_regs_t typedef, which we need to
5960	 * check before we skip all the typedef below.
5961	 */
5962	if (prog_type == BPF_PROG_TYPE_KPROBE) {
5963		while (btf_type_is_modifier(t) && !btf_type_is_typedef(t))
5964			t = btf_type_by_id(btf, t->type);
5965
5966		if (btf_type_is_typedef(t)) {
5967			tname = btf_name_by_offset(btf, t->name_off);
5968			if (tname && strcmp(tname, "bpf_user_pt_regs_t") == 0)
5969				return true;
5970		}
5971	}
5972
5973	while (btf_type_is_modifier(t))
5974		t = btf_type_by_id(btf, t->type);
5975	if (!btf_type_is_struct(t)) {
5976		/* Only pointer to struct is supported for now.
5977		 * That means that BPF_PROG_TYPE_TRACEPOINT with BTF
5978		 * is not supported yet.
5979		 * BPF_PROG_TYPE_RAW_TRACEPOINT is fine.
5980		 */
5981		return false;
5982	}
5983	tname = btf_name_by_offset(btf, t->name_off);
5984	if (!tname) {
5985		bpf_log(log, "arg#%d struct doesn't have a name\n", arg);
5986		return false;
5987	}
5988
5989	ctx_type = find_canonical_prog_ctx_type(prog_type);
5990	if (!ctx_type) {
5991		bpf_log(log, "btf_vmlinux is malformed\n");
5992		/* should not happen */
5993		return false;
5994	}
5995again:
5996	ctx_tname = btf_name_by_offset(btf_vmlinux, ctx_type->name_off);
5997	if (!ctx_tname) {
5998		/* should not happen */
5999		bpf_log(log, "Please fix kernel include/linux/bpf_types.h\n");
6000		return false;
6001	}
6002	/* program types without named context types work only with arg:ctx tag */
6003	if (ctx_tname[0] == '\0')
6004		return false;
6005	/* only compare that prog's ctx type name is the same as
6006	 * kernel expects. No need to compare field by field.
6007	 * It's ok for bpf prog to do:
6008	 * struct __sk_buff {};
6009	 * int socket_filter_bpf_prog(struct __sk_buff *skb)
6010	 * { // no fields of skb are ever used }
6011	 */
6012	if (btf_is_projection_of(ctx_tname, tname))
6013		return true;
6014	if (strcmp(ctx_tname, tname)) {
6015		/* bpf_user_pt_regs_t is a typedef, so resolve it to
6016		 * underlying struct and check name again
6017		 */
6018		if (!btf_type_is_modifier(ctx_type))
6019			return false;
6020		while (btf_type_is_modifier(ctx_type))
6021			ctx_type = btf_type_by_id(btf_vmlinux, ctx_type->type);
6022		goto again;
6023	}
6024	return true;
6025}
6026
6027/* forward declarations for arch-specific underlying types of
6028 * bpf_user_pt_regs_t; this avoids the need for arch-specific #ifdef
6029 * compilation guards below for BPF_PROG_TYPE_PERF_EVENT checks, but still
6030 * works correctly with __builtin_types_compatible_p() on respective
6031 * architectures
6032 */
6033struct user_regs_struct;
6034struct user_pt_regs;
6035
6036static int btf_validate_prog_ctx_type(struct bpf_verifier_log *log, const struct btf *btf,
6037				      const struct btf_type *t, int arg,
6038				      enum bpf_prog_type prog_type,
6039				      enum bpf_attach_type attach_type)
6040{
6041	const struct btf_type *ctx_type;
6042	const char *tname, *ctx_tname;
6043
6044	if (!btf_is_ptr(t)) {
6045		bpf_log(log, "arg#%d type isn't a pointer\n", arg);
6046		return -EINVAL;
6047	}
6048	t = btf_type_by_id(btf, t->type);
6049
6050	/* KPROBE and PERF_EVENT programs allow bpf_user_pt_regs_t typedef */
6051	if (prog_type == BPF_PROG_TYPE_KPROBE || prog_type == BPF_PROG_TYPE_PERF_EVENT) {
6052		while (btf_type_is_modifier(t) && !btf_type_is_typedef(t))
6053			t = btf_type_by_id(btf, t->type);
6054
6055		if (btf_type_is_typedef(t)) {
6056			tname = btf_name_by_offset(btf, t->name_off);
6057			if (tname && strcmp(tname, "bpf_user_pt_regs_t") == 0)
6058				return 0;
6059		}
6060	}
6061
6062	/* all other program types don't use typedefs for context type */
6063	while (btf_type_is_modifier(t))
6064		t = btf_type_by_id(btf, t->type);
6065
6066	/* `void *ctx __arg_ctx` is always valid */
6067	if (btf_type_is_void(t))
6068		return 0;
6069
6070	tname = btf_name_by_offset(btf, t->name_off);
6071	if (str_is_empty(tname)) {
6072		bpf_log(log, "arg#%d type doesn't have a name\n", arg);
6073		return -EINVAL;
6074	}
6075
6076	/* special cases */
6077	switch (prog_type) {
6078	case BPF_PROG_TYPE_KPROBE:
6079		if (__btf_type_is_struct(t) && strcmp(tname, "pt_regs") == 0)
6080			return 0;
6081		break;
6082	case BPF_PROG_TYPE_PERF_EVENT:
6083		if (__builtin_types_compatible_p(bpf_user_pt_regs_t, struct pt_regs) &&
6084		    __btf_type_is_struct(t) && strcmp(tname, "pt_regs") == 0)
6085			return 0;
6086		if (__builtin_types_compatible_p(bpf_user_pt_regs_t, struct user_pt_regs) &&
6087		    __btf_type_is_struct(t) && strcmp(tname, "user_pt_regs") == 0)
6088			return 0;
6089		if (__builtin_types_compatible_p(bpf_user_pt_regs_t, struct user_regs_struct) &&
6090		    __btf_type_is_struct(t) && strcmp(tname, "user_regs_struct") == 0)
6091			return 0;
6092		break;
6093	case BPF_PROG_TYPE_RAW_TRACEPOINT:
6094	case BPF_PROG_TYPE_RAW_TRACEPOINT_WRITABLE:
6095		/* allow u64* as ctx */
6096		if (btf_is_int(t) && t->size == 8)
6097			return 0;
6098		break;
6099	case BPF_PROG_TYPE_TRACING:
6100		switch (attach_type) {
6101		case BPF_TRACE_RAW_TP:
6102			/* tp_btf program is TRACING, so need special case here */
6103			if (__btf_type_is_struct(t) &&
6104			    strcmp(tname, "bpf_raw_tracepoint_args") == 0)
6105				return 0;
6106			/* allow u64* as ctx */
6107			if (btf_is_int(t) && t->size == 8)
6108				return 0;
6109			break;
6110		case BPF_TRACE_ITER:
6111			/* allow struct bpf_iter__xxx types only */
6112			if (__btf_type_is_struct(t) &&
6113			    strncmp(tname, "bpf_iter__", sizeof("bpf_iter__") - 1) == 0)
6114				return 0;
6115			break;
6116		case BPF_TRACE_FENTRY:
6117		case BPF_TRACE_FEXIT:
6118		case BPF_MODIFY_RETURN:
6119			/* allow u64* as ctx */
6120			if (btf_is_int(t) && t->size == 8)
6121				return 0;
6122			break;
6123		default:
6124			break;
6125		}
6126		break;
6127	case BPF_PROG_TYPE_LSM:
6128	case BPF_PROG_TYPE_STRUCT_OPS:
6129		/* allow u64* as ctx */
6130		if (btf_is_int(t) && t->size == 8)
6131			return 0;
6132		break;
6133	case BPF_PROG_TYPE_TRACEPOINT:
6134	case BPF_PROG_TYPE_SYSCALL:
6135	case BPF_PROG_TYPE_EXT:
6136		return 0; /* anything goes */
6137	default:
6138		break;
6139	}
6140
6141	ctx_type = find_canonical_prog_ctx_type(prog_type);
6142	if (!ctx_type) {
6143		/* should not happen */
6144		bpf_log(log, "btf_vmlinux is malformed\n");
6145		return -EINVAL;
6146	}
6147
6148	/* resolve typedefs and check that underlying structs are matching as well */
6149	while (btf_type_is_modifier(ctx_type))
6150		ctx_type = btf_type_by_id(btf_vmlinux, ctx_type->type);
6151
6152	/* if program type doesn't have distinctly named struct type for
6153	 * context, then __arg_ctx argument can only be `void *`, which we
6154	 * already checked above
6155	 */
6156	if (!__btf_type_is_struct(ctx_type)) {
6157		bpf_log(log, "arg#%d should be void pointer\n", arg);
6158		return -EINVAL;
6159	}
6160
6161	ctx_tname = btf_name_by_offset(btf_vmlinux, ctx_type->name_off);
6162	if (!__btf_type_is_struct(t) || strcmp(ctx_tname, tname) != 0) {
6163		bpf_log(log, "arg#%d should be `struct %s *`\n", arg, ctx_tname);
6164		return -EINVAL;
6165	}
6166
6167	return 0;
6168}
6169
6170static int btf_translate_to_vmlinux(struct bpf_verifier_log *log,
6171				     struct btf *btf,
6172				     const struct btf_type *t,
6173				     enum bpf_prog_type prog_type,
6174				     int arg)
6175{
6176	if (!btf_is_prog_ctx_type(log, btf, t, prog_type, arg))
6177		return -ENOENT;
6178	return find_kern_ctx_type_id(prog_type);
6179}
6180
6181int get_kern_ctx_btf_id(struct bpf_verifier_log *log, enum bpf_prog_type prog_type)
6182{
6183	const struct btf_member *kctx_member;
6184	const struct btf_type *conv_struct;
6185	const struct btf_type *kctx_type;
6186	u32 kctx_type_id;
6187
6188	conv_struct = bpf_ctx_convert.t;
6189	/* get member for kernel ctx type */
6190	kctx_member = btf_type_member(conv_struct) + bpf_ctx_convert_map[prog_type] * 2 + 1;
6191	kctx_type_id = kctx_member->type;
6192	kctx_type = btf_type_by_id(btf_vmlinux, kctx_type_id);
6193	if (!btf_type_is_struct(kctx_type)) {
6194		bpf_log(log, "kern ctx type id %u is not a struct\n", kctx_type_id);
6195		return -EINVAL;
6196	}
6197
6198	return kctx_type_id;
6199}
6200
6201BTF_ID_LIST_SINGLE(bpf_ctx_convert_btf_id, struct, bpf_ctx_convert)
6202
6203static struct btf *btf_parse_base(struct btf_verifier_env *env, const char *name,
6204				  void *data, unsigned int data_size)
6205{
6206	struct btf *btf = NULL;
6207	int err;
6208
6209	if (!IS_ENABLED(CONFIG_DEBUG_INFO_BTF))
6210		return ERR_PTR(-ENOENT);
6211
6212	btf = kzalloc(sizeof(*btf), GFP_KERNEL | __GFP_NOWARN);
6213	if (!btf) {
6214		err = -ENOMEM;
6215		goto errout;
6216	}
6217	env->btf = btf;
6218
6219	btf->data = data;
6220	btf->data_size = data_size;
6221	btf->kernel_btf = true;
6222	snprintf(btf->name, sizeof(btf->name), "%s", name);
6223
6224	err = btf_parse_hdr(env);
6225	if (err)
6226		goto errout;
6227
6228	btf->nohdr_data = btf->data + btf->hdr.hdr_len;
6229
6230	err = btf_parse_str_sec(env);
6231	if (err)
6232		goto errout;
6233
6234	err = btf_check_all_metas(env);
6235	if (err)
6236		goto errout;
6237
6238	err = btf_check_type_tags(env, btf, 1);
6239	if (err)
6240		goto errout;
6241
6242	refcount_set(&btf->refcnt, 1);
6243
6244	return btf;
6245
6246errout:
6247	if (btf) {
6248		kvfree(btf->types);
6249		kfree(btf);
6250	}
6251	return ERR_PTR(err);
6252}
6253
6254struct btf *btf_parse_vmlinux(void)
6255{
6256	struct btf_verifier_env *env = NULL;
6257	struct bpf_verifier_log *log;
6258	struct btf *btf;
6259	int err;
6260
6261	env = kzalloc(sizeof(*env), GFP_KERNEL | __GFP_NOWARN);
6262	if (!env)
6263		return ERR_PTR(-ENOMEM);
6264
6265	log = &env->log;
6266	log->level = BPF_LOG_KERNEL;
6267	btf = btf_parse_base(env, "vmlinux", __start_BTF, __stop_BTF - __start_BTF);
6268	if (IS_ERR(btf))
6269		goto err_out;
6270
6271	/* btf_parse_vmlinux() runs under bpf_verifier_lock */
6272	bpf_ctx_convert.t = btf_type_by_id(btf, bpf_ctx_convert_btf_id[0]);
6273	err = btf_alloc_id(btf);
6274	if (err) {
6275		btf_free(btf);
6276		btf = ERR_PTR(err);
6277	}
6278err_out:
6279	btf_verifier_env_free(env);
6280	return btf;
6281}
6282
6283/* If .BTF_ids section was created with distilled base BTF, both base and
6284 * split BTF ids will need to be mapped to actual base/split ids for
6285 * BTF now that it has been relocated.
6286 */
6287static __u32 btf_relocate_id(const struct btf *btf, __u32 id)
6288{
6289	if (!btf->base_btf || !btf->base_id_map)
6290		return id;
6291	return btf->base_id_map[id];
6292}
6293
6294#ifdef CONFIG_DEBUG_INFO_BTF_MODULES
6295
6296static struct btf *btf_parse_module(const char *module_name, const void *data,
6297				    unsigned int data_size, void *base_data,
6298				    unsigned int base_data_size)
6299{
6300	struct btf *btf = NULL, *vmlinux_btf, *base_btf = NULL;
6301	struct btf_verifier_env *env = NULL;
6302	struct bpf_verifier_log *log;
6303	int err = 0;
6304
6305	vmlinux_btf = bpf_get_btf_vmlinux();
6306	if (IS_ERR(vmlinux_btf))
6307		return vmlinux_btf;
6308	if (!vmlinux_btf)
6309		return ERR_PTR(-EINVAL);
6310
6311	env = kzalloc(sizeof(*env), GFP_KERNEL | __GFP_NOWARN);
6312	if (!env)
6313		return ERR_PTR(-ENOMEM);
6314
6315	log = &env->log;
6316	log->level = BPF_LOG_KERNEL;
6317
6318	if (base_data) {
6319		base_btf = btf_parse_base(env, ".BTF.base", base_data, base_data_size);
6320		if (IS_ERR(base_btf)) {
6321			err = PTR_ERR(base_btf);
6322			goto errout;
6323		}
6324	} else {
6325		base_btf = vmlinux_btf;
6326	}
6327
6328	btf = kzalloc(sizeof(*btf), GFP_KERNEL | __GFP_NOWARN);
6329	if (!btf) {
6330		err = -ENOMEM;
6331		goto errout;
6332	}
6333	env->btf = btf;
6334
6335	btf->base_btf = base_btf;
6336	btf->start_id = base_btf->nr_types;
6337	btf->start_str_off = base_btf->hdr.str_len;
6338	btf->kernel_btf = true;
6339	snprintf(btf->name, sizeof(btf->name), "%s", module_name);
6340
6341	btf->data = kvmemdup(data, data_size, GFP_KERNEL | __GFP_NOWARN);
6342	if (!btf->data) {
6343		err = -ENOMEM;
6344		goto errout;
6345	}
6346	btf->data_size = data_size;
6347
6348	err = btf_parse_hdr(env);
6349	if (err)
6350		goto errout;
6351
6352	btf->nohdr_data = btf->data + btf->hdr.hdr_len;
6353
6354	err = btf_parse_str_sec(env);
6355	if (err)
6356		goto errout;
6357
6358	err = btf_check_all_metas(env);
6359	if (err)
6360		goto errout;
6361
6362	err = btf_check_type_tags(env, btf, btf_nr_types(base_btf));
6363	if (err)
6364		goto errout;
6365
6366	if (base_btf != vmlinux_btf) {
6367		err = btf_relocate(btf, vmlinux_btf, &btf->base_id_map);
6368		if (err)
6369			goto errout;
6370		btf_free(base_btf);
6371		base_btf = vmlinux_btf;
6372	}
6373
6374	btf_verifier_env_free(env);
6375	refcount_set(&btf->refcnt, 1);
6376	return btf;
6377
6378errout:
6379	btf_verifier_env_free(env);
6380	if (!IS_ERR(base_btf) && base_btf != vmlinux_btf)
6381		btf_free(base_btf);
6382	if (btf) {
6383		kvfree(btf->data);
6384		kvfree(btf->types);
6385		kfree(btf);
6386	}
6387	return ERR_PTR(err);
6388}
6389
6390#endif /* CONFIG_DEBUG_INFO_BTF_MODULES */
6391
6392struct btf *bpf_prog_get_target_btf(const struct bpf_prog *prog)
6393{
6394	struct bpf_prog *tgt_prog = prog->aux->dst_prog;
6395
6396	if (tgt_prog)
6397		return tgt_prog->aux->btf;
6398	else
6399		return prog->aux->attach_btf;
6400}
6401
6402static bool is_void_or_int_ptr(struct btf *btf, const struct btf_type *t)
6403{
6404	/* skip modifiers */
6405	t = btf_type_skip_modifiers(btf, t->type, NULL);
6406	return btf_type_is_void(t) || btf_type_is_int(t);
6407}
6408
6409u32 btf_ctx_arg_idx(struct btf *btf, const struct btf_type *func_proto,
6410		    int off)
6411{
6412	const struct btf_param *args;
6413	const struct btf_type *t;
6414	u32 offset = 0, nr_args;
6415	int i;
6416
6417	if (!func_proto)
6418		return off / 8;
6419
6420	nr_args = btf_type_vlen(func_proto);
6421	args = (const struct btf_param *)(func_proto + 1);
6422	for (i = 0; i < nr_args; i++) {
6423		t = btf_type_skip_modifiers(btf, args[i].type, NULL);
6424		offset += btf_type_is_ptr(t) ? 8 : roundup(t->size, 8);
6425		if (off < offset)
6426			return i;
6427	}
6428
6429	t = btf_type_skip_modifiers(btf, func_proto->type, NULL);
6430	offset += btf_type_is_ptr(t) ? 8 : roundup(t->size, 8);
6431	if (off < offset)
6432		return nr_args;
6433
6434	return nr_args + 1;
6435}
6436
6437static bool prog_args_trusted(const struct bpf_prog *prog)
6438{
6439	enum bpf_attach_type atype = prog->expected_attach_type;
6440
6441	switch (prog->type) {
6442	case BPF_PROG_TYPE_TRACING:
6443		return atype == BPF_TRACE_RAW_TP || atype == BPF_TRACE_ITER;
6444	case BPF_PROG_TYPE_LSM:
6445		return bpf_lsm_is_trusted(prog);
6446	case BPF_PROG_TYPE_STRUCT_OPS:
6447		return true;
6448	default:
6449		return false;
6450	}
6451}
6452
6453int btf_ctx_arg_offset(const struct btf *btf, const struct btf_type *func_proto,
6454		       u32 arg_no)
6455{
6456	const struct btf_param *args;
6457	const struct btf_type *t;
6458	int off = 0, i;
6459	u32 sz;
6460
6461	args = btf_params(func_proto);
6462	for (i = 0; i < arg_no; i++) {
6463		t = btf_type_by_id(btf, args[i].type);
6464		t = btf_resolve_size(btf, t, &sz);
6465		if (IS_ERR(t))
6466			return PTR_ERR(t);
6467		off += roundup(sz, 8);
6468	}
6469
6470	return off;
6471}
6472
6473struct bpf_raw_tp_null_args {
6474	const char *func;
6475	u64 mask;
6476};
6477
6478static const struct bpf_raw_tp_null_args raw_tp_null_args[] = {
6479	/* sched */
6480	{ "sched_pi_setprio", 0x10 },
6481	/* ... from sched_numa_pair_template event class */
6482	{ "sched_stick_numa", 0x100 },
6483	{ "sched_swap_numa", 0x100 },
6484	/* afs */
6485	{ "afs_make_fs_call", 0x10 },
6486	{ "afs_make_fs_calli", 0x10 },
6487	{ "afs_make_fs_call1", 0x10 },
6488	{ "afs_make_fs_call2", 0x10 },
6489	{ "afs_protocol_error", 0x1 },
6490	{ "afs_flock_ev", 0x10 },
6491	/* cachefiles */
6492	{ "cachefiles_lookup", 0x1 | 0x200 },
6493	{ "cachefiles_unlink", 0x1 },
6494	{ "cachefiles_rename", 0x1 },
6495	{ "cachefiles_prep_read", 0x1 },
6496	{ "cachefiles_mark_active", 0x1 },
6497	{ "cachefiles_mark_failed", 0x1 },
6498	{ "cachefiles_mark_inactive", 0x1 },
6499	{ "cachefiles_vfs_error", 0x1 },
6500	{ "cachefiles_io_error", 0x1 },
6501	{ "cachefiles_ondemand_open", 0x1 },
6502	{ "cachefiles_ondemand_copen", 0x1 },
6503	{ "cachefiles_ondemand_close", 0x1 },
6504	{ "cachefiles_ondemand_read", 0x1 },
6505	{ "cachefiles_ondemand_cread", 0x1 },
6506	{ "cachefiles_ondemand_fd_write", 0x1 },
6507	{ "cachefiles_ondemand_fd_release", 0x1 },
6508	/* ext4, from ext4__mballoc event class */
6509	{ "ext4_mballoc_discard", 0x10 },
6510	{ "ext4_mballoc_free", 0x10 },
6511	/* fib */
6512	{ "fib_table_lookup", 0x100 },
6513	/* filelock */
6514	/* ... from filelock_lock event class */
6515	{ "posix_lock_inode", 0x10 },
6516	{ "fcntl_setlk", 0x10 },
6517	{ "locks_remove_posix", 0x10 },
6518	{ "flock_lock_inode", 0x10 },
6519	/* ... from filelock_lease event class */
6520	{ "break_lease_noblock", 0x10 },
6521	{ "break_lease_block", 0x10 },
6522	{ "break_lease_unblock", 0x10 },
6523	{ "generic_delete_lease", 0x10 },
6524	{ "time_out_leases", 0x10 },
6525	/* host1x */
6526	{ "host1x_cdma_push_gather", 0x10000 },
6527	/* huge_memory */
6528	{ "mm_khugepaged_scan_pmd", 0x10 },
6529	{ "mm_collapse_huge_page_isolate", 0x1 },
6530	{ "mm_khugepaged_scan_file", 0x10 },
6531	{ "mm_khugepaged_collapse_file", 0x10 },
6532	/* kmem */
6533	{ "mm_page_alloc", 0x1 },
6534	{ "mm_page_pcpu_drain", 0x1 },
6535	/* .. from mm_page event class */
6536	{ "mm_page_alloc_zone_locked", 0x1 },
6537	/* netfs */
6538	{ "netfs_failure", 0x10 },
6539	/* power */
6540	{ "device_pm_callback_start", 0x10 },
6541	/* qdisc */
6542	{ "qdisc_dequeue", 0x1000 },
6543	/* rxrpc */
6544	{ "rxrpc_recvdata", 0x1 },
6545	{ "rxrpc_resend", 0x10 },
6546	{ "rxrpc_tq", 0x10 },
6547	{ "rxrpc_client", 0x1 },
6548	/* skb */
6549	{"kfree_skb", 0x1000},
6550	/* sunrpc */
6551	{ "xs_stream_read_data", 0x1 },
6552	/* ... from xprt_cong_event event class */
6553	{ "xprt_reserve_cong", 0x10 },
6554	{ "xprt_release_cong", 0x10 },
6555	{ "xprt_get_cong", 0x10 },
6556	{ "xprt_put_cong", 0x10 },
6557	/* tcp */
6558	{ "tcp_send_reset", 0x11 },
6559	{ "tcp_sendmsg_locked", 0x100 },
6560	/* tegra_apb_dma */
6561	{ "tegra_dma_tx_status", 0x100 },
6562	/* timer_migration */
6563	{ "tmigr_update_events", 0x1 },
6564	/* writeback, from writeback_folio_template event class */
6565	{ "writeback_dirty_folio", 0x10 },
6566	{ "folio_wait_writeback", 0x10 },
6567	/* rdma */
6568	{ "mr_integ_alloc", 0x2000 },
6569	/* bpf_testmod */
6570	{ "bpf_testmod_test_read", 0x0 },
6571	/* amdgpu */
6572	{ "amdgpu_vm_bo_map", 0x1 },
6573	{ "amdgpu_vm_bo_unmap", 0x1 },
6574	/* netfs */
6575	{ "netfs_folioq", 0x1 },
6576	/* xfs from xfs_defer_pending_class */
6577	{ "xfs_defer_create_intent", 0x1 },
6578	{ "xfs_defer_cancel_list", 0x1 },
6579	{ "xfs_defer_pending_finish", 0x1 },
6580	{ "xfs_defer_pending_abort", 0x1 },
6581	{ "xfs_defer_relog_intent", 0x1 },
6582	{ "xfs_defer_isolate_paused", 0x1 },
6583	{ "xfs_defer_item_pause", 0x1 },
6584	{ "xfs_defer_item_unpause", 0x1 },
6585	/* xfs from xfs_defer_pending_item_class */
6586	{ "xfs_defer_add_item", 0x1 },
6587	{ "xfs_defer_cancel_item", 0x1 },
6588	{ "xfs_defer_finish_item", 0x1 },
6589	/* xfs from xfs_icwalk_class */
6590	{ "xfs_ioc_free_eofblocks", 0x10 },
6591	{ "xfs_blockgc_free_space", 0x10 },
6592	/* xfs from xfs_btree_cur_class */
6593	{ "xfs_btree_updkeys", 0x100 },
6594	{ "xfs_btree_overlapped_query_range", 0x100 },
6595	/* xfs from xfs_imap_class*/
6596	{ "xfs_map_blocks_found", 0x10000 },
6597	{ "xfs_map_blocks_alloc", 0x10000 },
6598	{ "xfs_iomap_alloc", 0x1000 },
6599	{ "xfs_iomap_found", 0x1000 },
6600	/* xfs from xfs_fs_class */
6601	{ "xfs_inodegc_flush", 0x1 },
6602	{ "xfs_inodegc_push", 0x1 },
6603	{ "xfs_inodegc_start", 0x1 },
6604	{ "xfs_inodegc_stop", 0x1 },
6605	{ "xfs_inodegc_queue", 0x1 },
6606	{ "xfs_inodegc_throttle", 0x1 },
6607	{ "xfs_fs_sync_fs", 0x1 },
6608	{ "xfs_blockgc_start", 0x1 },
6609	{ "xfs_blockgc_stop", 0x1 },
6610	{ "xfs_blockgc_worker", 0x1 },
6611	{ "xfs_blockgc_flush_all", 0x1 },
6612	/* xfs_scrub */
6613	{ "xchk_nlinks_live_update", 0x10 },
6614	/* xfs_scrub from xchk_metapath_class */
6615	{ "xchk_metapath_lookup", 0x100 },
6616	/* nfsd */
6617	{ "nfsd_dirent", 0x1 },
6618	{ "nfsd_file_acquire", 0x1001 },
6619	{ "nfsd_file_insert_err", 0x1 },
6620	{ "nfsd_file_cons_err", 0x1 },
6621	/* nfs4 */
6622	{ "nfs4_setup_sequence", 0x1 },
6623	{ "pnfs_update_layout", 0x10000 },
6624	{ "nfs4_inode_callback_event", 0x200 },
6625	{ "nfs4_inode_stateid_callback_event", 0x200 },
6626	/* nfs from pnfs_layout_event */
6627	{ "pnfs_mds_fallback_pg_init_read", 0x10000 },
6628	{ "pnfs_mds_fallback_pg_init_write", 0x10000 },
6629	{ "pnfs_mds_fallback_pg_get_mirror_count", 0x10000 },
6630	{ "pnfs_mds_fallback_read_done", 0x10000 },
6631	{ "pnfs_mds_fallback_write_done", 0x10000 },
6632	{ "pnfs_mds_fallback_read_pagelist", 0x10000 },
6633	{ "pnfs_mds_fallback_write_pagelist", 0x10000 },
6634	/* coda */
6635	{ "coda_dec_pic_run", 0x10 },
6636	{ "coda_dec_pic_done", 0x10 },
6637	/* cfg80211 */
6638	{ "cfg80211_scan_done", 0x11 },
6639	{ "rdev_set_coalesce", 0x10 },
6640	{ "cfg80211_report_wowlan_wakeup", 0x100 },
6641	{ "cfg80211_inform_bss_frame", 0x100 },
6642	{ "cfg80211_michael_mic_failure", 0x10000 },
6643	/* cfg80211 from wiphy_work_event */
6644	{ "wiphy_work_queue", 0x10 },
6645	{ "wiphy_work_run", 0x10 },
6646	{ "wiphy_work_cancel", 0x10 },
6647	{ "wiphy_work_flush", 0x10 },
6648	/* hugetlbfs */
6649	{ "hugetlbfs_alloc_inode", 0x10 },
6650	/* spufs */
6651	{ "spufs_context", 0x10 },
6652	/* kvm_hv */
6653	{ "kvm_page_fault_enter", 0x100 },
6654	/* dpu */
6655	{ "dpu_crtc_setup_mixer", 0x100 },
6656	/* binder */
6657	{ "binder_transaction", 0x100 },
6658	/* bcachefs */
6659	{ "btree_path_free", 0x100 },
6660	/* hfi1_tx */
6661	{ "hfi1_sdma_progress", 0x1000 },
6662	/* iptfs */
6663	{ "iptfs_ingress_postq_event", 0x1000 },
6664	/* neigh */
6665	{ "neigh_update", 0x10 },
6666	/* snd_firewire_lib */
6667	{ "amdtp_packet", 0x100 },
6668};
6669
6670bool btf_ctx_access(int off, int size, enum bpf_access_type type,
6671		    const struct bpf_prog *prog,
6672		    struct bpf_insn_access_aux *info)
6673{
6674	const struct btf_type *t = prog->aux->attach_func_proto;
6675	struct bpf_prog *tgt_prog = prog->aux->dst_prog;
6676	struct btf *btf = bpf_prog_get_target_btf(prog);
6677	const char *tname = prog->aux->attach_func_name;
6678	struct bpf_verifier_log *log = info->log;
6679	const struct btf_param *args;
6680	bool ptr_err_raw_tp = false;
6681	const char *tag_value;
6682	u32 nr_args, arg;
6683	int i, ret;
6684
6685	if (off % 8) {
6686		bpf_log(log, "func '%s' offset %d is not multiple of 8\n",
6687			tname, off);
6688		return false;
6689	}
6690	arg = btf_ctx_arg_idx(btf, t, off);
6691	args = (const struct btf_param *)(t + 1);
6692	/* if (t == NULL) Fall back to default BPF prog with
6693	 * MAX_BPF_FUNC_REG_ARGS u64 arguments.
6694	 */
6695	nr_args = t ? btf_type_vlen(t) : MAX_BPF_FUNC_REG_ARGS;
6696	if (prog->aux->attach_btf_trace) {
6697		/* skip first 'void *__data' argument in btf_trace_##name typedef */
6698		args++;
6699		nr_args--;
6700	}
6701
6702	if (arg > nr_args) {
6703		bpf_log(log, "func '%s' doesn't have %d-th argument\n",
6704			tname, arg + 1);
6705		return false;
6706	}
6707
6708	if (arg == nr_args) {
6709		switch (prog->expected_attach_type) {
6710		case BPF_LSM_MAC:
6711			/* mark we are accessing the return value */
6712			info->is_retval = true;
6713			fallthrough;
6714		case BPF_LSM_CGROUP:
6715		case BPF_TRACE_FEXIT:
6716			/* When LSM programs are attached to void LSM hooks
6717			 * they use FEXIT trampolines and when attached to
6718			 * int LSM hooks, they use MODIFY_RETURN trampolines.
6719			 *
6720			 * While the LSM programs are BPF_MODIFY_RETURN-like
6721			 * the check:
6722			 *
6723			 *	if (ret_type != 'int')
6724			 *		return -EINVAL;
6725			 *
6726			 * is _not_ done here. This is still safe as LSM hooks
6727			 * have only void and int return types.
6728			 */
6729			if (!t)
6730				return true;
6731			t = btf_type_by_id(btf, t->type);
6732			break;
6733		case BPF_MODIFY_RETURN:
6734			/* For now the BPF_MODIFY_RETURN can only be attached to
6735			 * functions that return an int.
6736			 */
6737			if (!t)
6738				return false;
6739
6740			t = btf_type_skip_modifiers(btf, t->type, NULL);
6741			if (!btf_type_is_small_int(t)) {
6742				bpf_log(log,
6743					"ret type %s not allowed for fmod_ret\n",
6744					btf_type_str(t));
6745				return false;
6746			}
6747			break;
6748		default:
6749			bpf_log(log, "func '%s' doesn't have %d-th argument\n",
6750				tname, arg + 1);
6751			return false;
6752		}
6753	} else {
6754		if (!t)
6755			/* Default prog with MAX_BPF_FUNC_REG_ARGS args */
6756			return true;
6757		t = btf_type_by_id(btf, args[arg].type);
6758	}
6759
6760	/* skip modifiers */
6761	while (btf_type_is_modifier(t))
6762		t = btf_type_by_id(btf, t->type);
6763	if (btf_type_is_small_int(t) || btf_is_any_enum(t) || btf_type_is_struct(t))
6764		/* accessing a scalar */
6765		return true;
6766	if (!btf_type_is_ptr(t)) {
6767		bpf_log(log,
6768			"func '%s' arg%d '%s' has type %s. Only pointer access is allowed\n",
6769			tname, arg,
6770			__btf_name_by_offset(btf, t->name_off),
6771			btf_type_str(t));
6772		return false;
6773	}
6774
6775	if (size != sizeof(u64)) {
6776		bpf_log(log, "func '%s' size %d must be 8\n",
6777			tname, size);
6778		return false;
6779	}
6780
6781	/* check for PTR_TO_RDONLY_BUF_OR_NULL or PTR_TO_RDWR_BUF_OR_NULL */
6782	for (i = 0; i < prog->aux->ctx_arg_info_size; i++) {
6783		const struct bpf_ctx_arg_aux *ctx_arg_info = &prog->aux->ctx_arg_info[i];
6784		u32 type, flag;
6785
6786		type = base_type(ctx_arg_info->reg_type);
6787		flag = type_flag(ctx_arg_info->reg_type);
6788		if (ctx_arg_info->offset == off && type == PTR_TO_BUF &&
6789		    (flag & PTR_MAYBE_NULL)) {
6790			info->reg_type = ctx_arg_info->reg_type;
6791			return true;
6792		}
6793	}
6794
6795	/*
6796	 * If it's a pointer to void, it's the same as scalar from the verifier
6797	 * safety POV. Either way, no futher pointer walking is allowed.
6798	 */
6799	if (is_void_or_int_ptr(btf, t))
6800		return true;
6801
6802	/* this is a pointer to another type */
6803	for (i = 0; i < prog->aux->ctx_arg_info_size; i++) {
6804		const struct bpf_ctx_arg_aux *ctx_arg_info = &prog->aux->ctx_arg_info[i];
6805
6806		if (ctx_arg_info->offset == off) {
6807			if (!ctx_arg_info->btf_id) {
6808				bpf_log(log,"invalid btf_id for context argument offset %u\n", off);
6809				return false;
6810			}
6811
6812			info->reg_type = ctx_arg_info->reg_type;
6813			info->btf = ctx_arg_info->btf ? : btf_vmlinux;
6814			info->btf_id = ctx_arg_info->btf_id;
6815			info->ref_obj_id = ctx_arg_info->ref_obj_id;
6816			return true;
6817		}
6818	}
6819
6820	info->reg_type = PTR_TO_BTF_ID;
6821	if (prog_args_trusted(prog))
6822		info->reg_type |= PTR_TRUSTED;
6823
6824	if (btf_param_match_suffix(btf, &args[arg], "__nullable"))
6825		info->reg_type |= PTR_MAYBE_NULL;
6826
6827	if (prog->expected_attach_type == BPF_TRACE_RAW_TP) {
6828		struct btf *btf = prog->aux->attach_btf;
6829		const struct btf_type *t;
6830		const char *tname;
6831
6832		/* BTF lookups cannot fail, return false on error */
6833		t = btf_type_by_id(btf, prog->aux->attach_btf_id);
6834		if (!t)
6835			return false;
6836		tname = btf_name_by_offset(btf, t->name_off);
6837		if (!tname)
6838			return false;
6839		/* Checked by bpf_check_attach_target */
6840		tname += sizeof("btf_trace_") - 1;
6841		for (i = 0; i < ARRAY_SIZE(raw_tp_null_args); i++) {
6842			/* Is this a func with potential NULL args? */
6843			if (strcmp(tname, raw_tp_null_args[i].func))
6844				continue;
6845			if (raw_tp_null_args[i].mask & (0x1ULL << (arg * 4)))
6846				info->reg_type |= PTR_MAYBE_NULL;
6847			/* Is the current arg IS_ERR? */
6848			if (raw_tp_null_args[i].mask & (0x2ULL << (arg * 4)))
6849				ptr_err_raw_tp = true;
6850			break;
6851		}
6852		/* If we don't know NULL-ness specification and the tracepoint
6853		 * is coming from a loadable module, be conservative and mark
6854		 * argument as PTR_MAYBE_NULL.
6855		 */
6856		if (i == ARRAY_SIZE(raw_tp_null_args) && btf_is_module(btf))
6857			info->reg_type |= PTR_MAYBE_NULL;
6858	}
6859
6860	if (tgt_prog) {
6861		enum bpf_prog_type tgt_type;
6862
6863		if (tgt_prog->type == BPF_PROG_TYPE_EXT)
6864			tgt_type = tgt_prog->aux->saved_dst_prog_type;
6865		else
6866			tgt_type = tgt_prog->type;
6867
6868		ret = btf_translate_to_vmlinux(log, btf, t, tgt_type, arg);
6869		if (ret > 0) {
6870			info->btf = btf_vmlinux;
6871			info->btf_id = ret;
6872			return true;
6873		} else {
6874			return false;
6875		}
6876	}
6877
6878	info->btf = btf;
6879	info->btf_id = t->type;
6880	t = btf_type_by_id(btf, t->type);
6881
6882	if (btf_type_is_type_tag(t) && !btf_type_kflag(t)) {
6883		tag_value = __btf_name_by_offset(btf, t->name_off);
6884		if (strcmp(tag_value, "user") == 0)
6885			info->reg_type |= MEM_USER;
6886		if (strcmp(tag_value, "percpu") == 0)
6887			info->reg_type |= MEM_PERCPU;
6888	}
6889
6890	/* skip modifiers */
6891	while (btf_type_is_modifier(t)) {
6892		info->btf_id = t->type;
6893		t = btf_type_by_id(btf, t->type);
6894	}
6895	if (!btf_type_is_struct(t)) {
6896		bpf_log(log,
6897			"func '%s' arg%d type %s is not a struct\n",
6898			tname, arg, btf_type_str(t));
6899		return false;
6900	}
6901	bpf_log(log, "func '%s' arg%d has btf_id %d type %s '%s'\n",
6902		tname, arg, info->btf_id, btf_type_str(t),
6903		__btf_name_by_offset(btf, t->name_off));
6904
6905	/* Perform all checks on the validity of type for this argument, but if
6906	 * we know it can be IS_ERR at runtime, scrub pointer type and mark as
6907	 * scalar.
6908	 */
6909	if (ptr_err_raw_tp) {
6910		bpf_log(log, "marking pointer arg%d as scalar as it may encode error", arg);
6911		info->reg_type = SCALAR_VALUE;
6912	}
6913	return true;
6914}
6915EXPORT_SYMBOL_GPL(btf_ctx_access);
6916
6917enum bpf_struct_walk_result {
6918	/* < 0 error */
6919	WALK_SCALAR = 0,
6920	WALK_PTR,
6921	WALK_PTR_UNTRUSTED,
6922	WALK_STRUCT,
6923};
6924
6925static int btf_struct_walk(struct bpf_verifier_log *log, const struct btf *btf,
6926			   const struct btf_type *t, int off, int size,
6927			   u32 *next_btf_id, enum bpf_type_flag *flag,
6928			   const char **field_name)
6929{
6930	u32 i, moff, mtrue_end, msize = 0, total_nelems = 0;
6931	const struct btf_type *mtype, *elem_type = NULL;
6932	const struct btf_member *member;
6933	const char *tname, *mname, *tag_value;
6934	u32 vlen, elem_id, mid;
6935
6936again:
6937	if (btf_type_is_modifier(t))
6938		t = btf_type_skip_modifiers(btf, t->type, NULL);
6939	tname = __btf_name_by_offset(btf, t->name_off);
6940	if (!btf_type_is_struct(t)) {
6941		bpf_log(log, "Type '%s' is not a struct\n", tname);
6942		return -EINVAL;
6943	}
6944
6945	vlen = btf_type_vlen(t);
6946	if (BTF_INFO_KIND(t->info) == BTF_KIND_UNION && vlen != 1 && !(*flag & PTR_UNTRUSTED))
6947		/*
6948		 * walking unions yields untrusted pointers
6949		 * with exception of __bpf_md_ptr and other
6950		 * unions with a single member
6951		 */
6952		*flag |= PTR_UNTRUSTED;
6953
6954	if (off + size > t->size) {
6955		/* If the last element is a variable size array, we may
6956		 * need to relax the rule.
6957		 */
6958		struct btf_array *array_elem;
6959
6960		if (vlen == 0)
6961			goto error;
6962
6963		member = btf_type_member(t) + vlen - 1;
6964		mtype = btf_type_skip_modifiers(btf, member->type,
6965						NULL);
6966		if (!btf_type_is_array(mtype))
6967			goto error;
6968
6969		array_elem = (struct btf_array *)(mtype + 1);
6970		if (array_elem->nelems != 0)
6971			goto error;
6972
6973		moff = __btf_member_bit_offset(t, member) / 8;
6974		if (off < moff)
6975			goto error;
6976
6977		/* allow structure and integer */
6978		t = btf_type_skip_modifiers(btf, array_elem->type,
6979					    NULL);
6980
6981		if (btf_type_is_int(t))
6982			return WALK_SCALAR;
6983
6984		if (!btf_type_is_struct(t))
6985			goto error;
6986
6987		off = (off - moff) % t->size;
6988		goto again;
6989
6990error:
6991		bpf_log(log, "access beyond struct %s at off %u size %u\n",
6992			tname, off, size);
6993		return -EACCES;
6994	}
6995
6996	for_each_member(i, t, member) {
6997		/* offset of the field in bytes */
6998		moff = __btf_member_bit_offset(t, member) / 8;
6999		if (off + size <= moff)
7000			/* won't find anything, field is already too far */
7001			break;
7002
7003		if (__btf_member_bitfield_size(t, member)) {
7004			u32 end_bit = __btf_member_bit_offset(t, member) +
7005				__btf_member_bitfield_size(t, member);
7006
7007			/* off <= moff instead of off == moff because clang
7008			 * does not generate a BTF member for anonymous
7009			 * bitfield like the ":16" here:
7010			 * struct {
7011			 *	int :16;
7012			 *	int x:8;
7013			 * };
7014			 */
7015			if (off <= moff &&
7016			    BITS_ROUNDUP_BYTES(end_bit) <= off + size)
7017				return WALK_SCALAR;
7018
7019			/* off may be accessing a following member
7020			 *
7021			 * or
7022			 *
7023			 * Doing partial access at either end of this
7024			 * bitfield.  Continue on this case also to
7025			 * treat it as not accessing this bitfield
7026			 * and eventually error out as field not
7027			 * found to keep it simple.
7028			 * It could be relaxed if there was a legit
7029			 * partial access case later.
7030			 */
7031			continue;
7032		}
7033
7034		/* In case of "off" is pointing to holes of a struct */
7035		if (off < moff)
7036			break;
7037
7038		/* type of the field */
7039		mid = member->type;
7040		mtype = btf_type_by_id(btf, member->type);
7041		mname = __btf_name_by_offset(btf, member->name_off);
7042
7043		mtype = __btf_resolve_size(btf, mtype, &msize,
7044					   &elem_type, &elem_id, &total_nelems,
7045					   &mid);
7046		if (IS_ERR(mtype)) {
7047			bpf_log(log, "field %s doesn't have size\n", mname);
7048			return -EFAULT;
7049		}
7050
7051		mtrue_end = moff + msize;
7052		if (off >= mtrue_end)
7053			/* no overlap with member, keep iterating */
7054			continue;
7055
7056		if (btf_type_is_array(mtype)) {
7057			u32 elem_idx;
7058
7059			/* __btf_resolve_size() above helps to
7060			 * linearize a multi-dimensional array.
7061			 *
7062			 * The logic here is treating an array
7063			 * in a struct as the following way:
7064			 *
7065			 * struct outer {
7066			 *	struct inner array[2][2];
7067			 * };
7068			 *
7069			 * looks like:
7070			 *
7071			 * struct outer {
7072			 *	struct inner array_elem0;
7073			 *	struct inner array_elem1;
7074			 *	struct inner array_elem2;
7075			 *	struct inner array_elem3;
7076			 * };
7077			 *
7078			 * When accessing outer->array[1][0], it moves
7079			 * moff to "array_elem2", set mtype to
7080			 * "struct inner", and msize also becomes
7081			 * sizeof(struct inner).  Then most of the
7082			 * remaining logic will fall through without
7083			 * caring the current member is an array or
7084			 * not.
7085			 *
7086			 * Unlike mtype/msize/moff, mtrue_end does not
7087			 * change.  The naming difference ("_true") tells
7088			 * that it is not always corresponding to
7089			 * the current mtype/msize/moff.
7090			 * It is the true end of the current
7091			 * member (i.e. array in this case).  That
7092			 * will allow an int array to be accessed like
7093			 * a scratch space,
7094			 * i.e. allow access beyond the size of
7095			 *      the array's element as long as it is
7096			 *      within the mtrue_end boundary.
7097			 */
7098
7099			/* skip empty array */
7100			if (moff == mtrue_end)
7101				continue;
7102
7103			msize /= total_nelems;
7104			elem_idx = (off - moff) / msize;
7105			moff += elem_idx * msize;
7106			mtype = elem_type;
7107			mid = elem_id;
7108		}
7109
7110		/* the 'off' we're looking for is either equal to start
7111		 * of this field or inside of this struct
7112		 */
7113		if (btf_type_is_struct(mtype)) {
7114			/* our field must be inside that union or struct */
7115			t = mtype;
7116
7117			/* return if the offset matches the member offset */
7118			if (off == moff) {
7119				*next_btf_id = mid;
7120				return WALK_STRUCT;
7121			}
7122
7123			/* adjust offset we're looking for */
7124			off -= moff;
7125			goto again;
7126		}
7127
7128		if (btf_type_is_ptr(mtype)) {
7129			const struct btf_type *stype, *t;
7130			enum bpf_type_flag tmp_flag = 0;
7131			u32 id;
7132
7133			if (msize != size || off != moff) {
7134				bpf_log(log,
7135					"cannot access ptr member %s with moff %u in struct %s with off %u size %u\n",
7136					mname, moff, tname, off, size);
7137				return -EACCES;
7138			}
7139
7140			/* check type tag */
7141			t = btf_type_by_id(btf, mtype->type);
7142			if (btf_type_is_type_tag(t) && !btf_type_kflag(t)) {
7143				tag_value = __btf_name_by_offset(btf, t->name_off);
7144				/* check __user tag */
7145				if (strcmp(tag_value, "user") == 0)
7146					tmp_flag = MEM_USER;
7147				/* check __percpu tag */
7148				if (strcmp(tag_value, "percpu") == 0)
7149					tmp_flag = MEM_PERCPU;
7150				/* check __rcu tag */
7151				if (strcmp(tag_value, "rcu") == 0)
7152					tmp_flag = MEM_RCU;
7153			}
7154
7155			stype = btf_type_skip_modifiers(btf, mtype->type, &id);
7156			if (btf_type_is_struct(stype)) {
7157				*next_btf_id = id;
7158				*flag |= tmp_flag;
7159				if (field_name)
7160					*field_name = mname;
7161				return WALK_PTR;
7162			}
7163
7164			return WALK_PTR_UNTRUSTED;
7165		}
7166
7167		/* Allow more flexible access within an int as long as
7168		 * it is within mtrue_end.
7169		 * Since mtrue_end could be the end of an array,
7170		 * that also allows using an array of int as a scratch
7171		 * space. e.g. skb->cb[].
7172		 */
7173		if (off + size > mtrue_end && !(*flag & PTR_UNTRUSTED)) {
7174			bpf_log(log,
7175				"access beyond the end of member %s (mend:%u) in struct %s with off %u size %u\n",
7176				mname, mtrue_end, tname, off, size);
7177			return -EACCES;
7178		}
7179
7180		return WALK_SCALAR;
7181	}
7182	bpf_log(log, "struct %s doesn't have field at offset %d\n", tname, off);
7183	return -EINVAL;
7184}
7185
7186int btf_struct_access(struct bpf_verifier_log *log,
7187		      const struct bpf_reg_state *reg,
7188		      int off, int size, enum bpf_access_type atype __maybe_unused,
7189		      u32 *next_btf_id, enum bpf_type_flag *flag,
7190		      const char **field_name)
7191{
7192	const struct btf *btf = reg->btf;
7193	enum bpf_type_flag tmp_flag = 0;
7194	const struct btf_type *t;
7195	u32 id = reg->btf_id;
7196	int err;
7197
7198	while (type_is_alloc(reg->type)) {
7199		struct btf_struct_meta *meta;
7200		struct btf_record *rec;
7201		int i;
7202
7203		meta = btf_find_struct_meta(btf, id);
7204		if (!meta)
7205			break;
7206		rec = meta->record;
7207		for (i = 0; i < rec->cnt; i++) {
7208			struct btf_field *field = &rec->fields[i];
7209			u32 offset = field->offset;
7210			if (off < offset + field->size && offset < off + size) {
7211				bpf_log(log,
7212					"direct access to %s is disallowed\n",
7213					btf_field_type_name(field->type));
7214				return -EACCES;
7215			}
7216		}
7217		break;
7218	}
7219
7220	t = btf_type_by_id(btf, id);
7221	do {
7222		err = btf_struct_walk(log, btf, t, off, size, &id, &tmp_flag, field_name);
7223
7224		switch (err) {
7225		case WALK_PTR:
7226			/* For local types, the destination register cannot
7227			 * become a pointer again.
7228			 */
7229			if (type_is_alloc(reg->type))
7230				return SCALAR_VALUE;
7231			/* If we found the pointer or scalar on t+off,
7232			 * we're done.
7233			 */
7234			*next_btf_id = id;
7235			*flag = tmp_flag;
7236			return PTR_TO_BTF_ID;
7237		case WALK_PTR_UNTRUSTED:
7238			*flag = MEM_RDONLY | PTR_UNTRUSTED;
7239			return PTR_TO_MEM;
7240		case WALK_SCALAR:
7241			return SCALAR_VALUE;
7242		case WALK_STRUCT:
7243			/* We found nested struct, so continue the search
7244			 * by diving in it. At this point the offset is
7245			 * aligned with the new type, so set it to 0.
7246			 */
7247			t = btf_type_by_id(btf, id);
7248			off = 0;
7249			break;
7250		default:
7251			/* It's either error or unknown return value..
7252			 * scream and leave.
7253			 */
7254			if (WARN_ONCE(err > 0, "unknown btf_struct_walk return value"))
7255				return -EINVAL;
7256			return err;
7257		}
7258	} while (t);
7259
7260	return -EINVAL;
7261}
7262
7263/* Check that two BTF types, each specified as an BTF object + id, are exactly
7264 * the same. Trivial ID check is not enough due to module BTFs, because we can
7265 * end up with two different module BTFs, but IDs point to the common type in
7266 * vmlinux BTF.
7267 */
7268bool btf_types_are_same(const struct btf *btf1, u32 id1,
7269			const struct btf *btf2, u32 id2)
7270{
7271	if (id1 != id2)
7272		return false;
7273	if (btf1 == btf2)
7274		return true;
7275	return btf_type_by_id(btf1, id1) == btf_type_by_id(btf2, id2);
7276}
7277
7278bool btf_struct_ids_match(struct bpf_verifier_log *log,
7279			  const struct btf *btf, u32 id, int off,
7280			  const struct btf *need_btf, u32 need_type_id,
7281			  bool strict)
7282{
7283	const struct btf_type *type;
7284	enum bpf_type_flag flag = 0;
7285	int err;
7286
7287	/* Are we already done? */
7288	if (off == 0 && btf_types_are_same(btf, id, need_btf, need_type_id))
7289		return true;
7290	/* In case of strict type match, we do not walk struct, the top level
7291	 * type match must succeed. When strict is true, off should have already
7292	 * been 0.
7293	 */
7294	if (strict)
7295		return false;
7296again:
7297	type = btf_type_by_id(btf, id);
7298	if (!type)
7299		return false;
7300	err = btf_struct_walk(log, btf, type, off, 1, &id, &flag, NULL);
7301	if (err != WALK_STRUCT)
7302		return false;
7303
7304	/* We found nested struct object. If it matches
7305	 * the requested ID, we're done. Otherwise let's
7306	 * continue the search with offset 0 in the new
7307	 * type.
7308	 */
7309	if (!btf_types_are_same(btf, id, need_btf, need_type_id)) {
7310		off = 0;
7311		goto again;
7312	}
7313
7314	return true;
7315}
7316
7317static int __get_type_size(struct btf *btf, u32 btf_id,
7318			   const struct btf_type **ret_type)
7319{
7320	const struct btf_type *t;
7321
7322	*ret_type = btf_type_by_id(btf, 0);
7323	if (!btf_id)
7324		/* void */
7325		return 0;
7326	t = btf_type_by_id(btf, btf_id);
7327	while (t && btf_type_is_modifier(t))
7328		t = btf_type_by_id(btf, t->type);
7329	if (!t)
7330		return -EINVAL;
7331	*ret_type = t;
7332	if (btf_type_is_ptr(t))
7333		/* kernel size of pointer. Not BPF's size of pointer*/
7334		return sizeof(void *);
7335	if (btf_type_is_int(t) || btf_is_any_enum(t) || btf_type_is_struct(t))
7336		return t->size;
7337	return -EINVAL;
7338}
7339
7340static u8 __get_type_fmodel_flags(const struct btf_type *t)
7341{
7342	u8 flags = 0;
7343
7344	if (btf_type_is_struct(t))
7345		flags |= BTF_FMODEL_STRUCT_ARG;
7346	if (btf_type_is_signed_int(t))
7347		flags |= BTF_FMODEL_SIGNED_ARG;
7348
7349	return flags;
7350}
7351
7352int btf_distill_func_proto(struct bpf_verifier_log *log,
7353			   struct btf *btf,
7354			   const struct btf_type *func,
7355			   const char *tname,
7356			   struct btf_func_model *m)
7357{
7358	const struct btf_param *args;
7359	const struct btf_type *t;
7360	u32 i, nargs;
7361	int ret;
7362
7363	if (!func) {
7364		/* BTF function prototype doesn't match the verifier types.
7365		 * Fall back to MAX_BPF_FUNC_REG_ARGS u64 args.
7366		 */
7367		for (i = 0; i < MAX_BPF_FUNC_REG_ARGS; i++) {
7368			m->arg_size[i] = 8;
7369			m->arg_flags[i] = 0;
7370		}
7371		m->ret_size = 8;
7372		m->ret_flags = 0;
7373		m->nr_args = MAX_BPF_FUNC_REG_ARGS;
7374		return 0;
7375	}
7376	args = (const struct btf_param *)(func + 1);
7377	nargs = btf_type_vlen(func);
7378	if (nargs > MAX_BPF_FUNC_ARGS) {
7379		bpf_log(log,
7380			"The function %s has %d arguments. Too many.\n",
7381			tname, nargs);
7382		return -EINVAL;
7383	}
7384	ret = __get_type_size(btf, func->type, &t);
7385	if (ret < 0 || btf_type_is_struct(t)) {
7386		bpf_log(log,
7387			"The function %s return type %s is unsupported.\n",
7388			tname, btf_type_str(t));
7389		return -EINVAL;
7390	}
7391	m->ret_size = ret;
7392	m->ret_flags = __get_type_fmodel_flags(t);
7393
7394	for (i = 0; i < nargs; i++) {
7395		if (i == nargs - 1 && args[i].type == 0) {
7396			bpf_log(log,
7397				"The function %s with variable args is unsupported.\n",
7398				tname);
7399			return -EINVAL;
7400		}
7401		ret = __get_type_size(btf, args[i].type, &t);
7402
7403		/* No support of struct argument size greater than 16 bytes */
7404		if (ret < 0 || ret > 16) {
7405			bpf_log(log,
7406				"The function %s arg%d type %s is unsupported.\n",
7407				tname, i, btf_type_str(t));
7408			return -EINVAL;
7409		}
7410		if (ret == 0) {
7411			bpf_log(log,
7412				"The function %s has malformed void argument.\n",
7413				tname);
7414			return -EINVAL;
7415		}
7416		m->arg_size[i] = ret;
7417		m->arg_flags[i] = __get_type_fmodel_flags(t);
7418	}
7419	m->nr_args = nargs;
7420	return 0;
7421}
7422
7423/* Compare BTFs of two functions assuming only scalars and pointers to context.
7424 * t1 points to BTF_KIND_FUNC in btf1
7425 * t2 points to BTF_KIND_FUNC in btf2
7426 * Returns:
7427 * EINVAL - function prototype mismatch
7428 * EFAULT - verifier bug
7429 * 0 - 99% match. The last 1% is validated by the verifier.
7430 */
7431static int btf_check_func_type_match(struct bpf_verifier_log *log,
7432				     struct btf *btf1, const struct btf_type *t1,
7433				     struct btf *btf2, const struct btf_type *t2)
7434{
7435	const struct btf_param *args1, *args2;
7436	const char *fn1, *fn2, *s1, *s2;
7437	u32 nargs1, nargs2, i;
7438
7439	fn1 = btf_name_by_offset(btf1, t1->name_off);
7440	fn2 = btf_name_by_offset(btf2, t2->name_off);
7441
7442	if (btf_func_linkage(t1) != BTF_FUNC_GLOBAL) {
7443		bpf_log(log, "%s() is not a global function\n", fn1);
7444		return -EINVAL;
7445	}
7446	if (btf_func_linkage(t2) != BTF_FUNC_GLOBAL) {
7447		bpf_log(log, "%s() is not a global function\n", fn2);
7448		return -EINVAL;
7449	}
7450
7451	t1 = btf_type_by_id(btf1, t1->type);
7452	if (!t1 || !btf_type_is_func_proto(t1))
7453		return -EFAULT;
7454	t2 = btf_type_by_id(btf2, t2->type);
7455	if (!t2 || !btf_type_is_func_proto(t2))
7456		return -EFAULT;
7457
7458	args1 = (const struct btf_param *)(t1 + 1);
7459	nargs1 = btf_type_vlen(t1);
7460	args2 = (const struct btf_param *)(t2 + 1);
7461	nargs2 = btf_type_vlen(t2);
7462
7463	if (nargs1 != nargs2) {
7464		bpf_log(log, "%s() has %d args while %s() has %d args\n",
7465			fn1, nargs1, fn2, nargs2);
7466		return -EINVAL;
7467	}
7468
7469	t1 = btf_type_skip_modifiers(btf1, t1->type, NULL);
7470	t2 = btf_type_skip_modifiers(btf2, t2->type, NULL);
7471	if (t1->info != t2->info) {
7472		bpf_log(log,
7473			"Return type %s of %s() doesn't match type %s of %s()\n",
7474			btf_type_str(t1), fn1,
7475			btf_type_str(t2), fn2);
7476		return -EINVAL;
7477	}
7478
7479	for (i = 0; i < nargs1; i++) {
7480		t1 = btf_type_skip_modifiers(btf1, args1[i].type, NULL);
7481		t2 = btf_type_skip_modifiers(btf2, args2[i].type, NULL);
7482
7483		if (t1->info != t2->info) {
7484			bpf_log(log, "arg%d in %s() is %s while %s() has %s\n",
7485				i, fn1, btf_type_str(t1),
7486				fn2, btf_type_str(t2));
7487			return -EINVAL;
7488		}
7489		if (btf_type_has_size(t1) && t1->size != t2->size) {
7490			bpf_log(log,
7491				"arg%d in %s() has size %d while %s() has %d\n",
7492				i, fn1, t1->size,
7493				fn2, t2->size);
7494			return -EINVAL;
7495		}
7496
7497		/* global functions are validated with scalars and pointers
7498		 * to context only. And only global functions can be replaced.
7499		 * Hence type check only those types.
7500		 */
7501		if (btf_type_is_int(t1) || btf_is_any_enum(t1))
7502			continue;
7503		if (!btf_type_is_ptr(t1)) {
7504			bpf_log(log,
7505				"arg%d in %s() has unrecognized type\n",
7506				i, fn1);
7507			return -EINVAL;
7508		}
7509		t1 = btf_type_skip_modifiers(btf1, t1->type, NULL);
7510		t2 = btf_type_skip_modifiers(btf2, t2->type, NULL);
7511		if (!btf_type_is_struct(t1)) {
7512			bpf_log(log,
7513				"arg%d in %s() is not a pointer to context\n",
7514				i, fn1);
7515			return -EINVAL;
7516		}
7517		if (!btf_type_is_struct(t2)) {
7518			bpf_log(log,
7519				"arg%d in %s() is not a pointer to context\n",
7520				i, fn2);
7521			return -EINVAL;
7522		}
7523		/* This is an optional check to make program writing easier.
7524		 * Compare names of structs and report an error to the user.
7525		 * btf_prepare_func_args() already checked that t2 struct
7526		 * is a context type. btf_prepare_func_args() will check
7527		 * later that t1 struct is a context type as well.
7528		 */
7529		s1 = btf_name_by_offset(btf1, t1->name_off);
7530		s2 = btf_name_by_offset(btf2, t2->name_off);
7531		if (strcmp(s1, s2)) {
7532			bpf_log(log,
7533				"arg%d %s(struct %s *) doesn't match %s(struct %s *)\n",
7534				i, fn1, s1, fn2, s2);
7535			return -EINVAL;
7536		}
7537	}
7538	return 0;
7539}
7540
7541/* Compare BTFs of given program with BTF of target program */
7542int btf_check_type_match(struct bpf_verifier_log *log, const struct bpf_prog *prog,
7543			 struct btf *btf2, const struct btf_type *t2)
7544{
7545	struct btf *btf1 = prog->aux->btf;
7546	const struct btf_type *t1;
7547	u32 btf_id = 0;
7548
7549	if (!prog->aux->func_info) {
7550		bpf_log(log, "Program extension requires BTF\n");
7551		return -EINVAL;
7552	}
7553
7554	btf_id = prog->aux->func_info[0].type_id;
7555	if (!btf_id)
7556		return -EFAULT;
7557
7558	t1 = btf_type_by_id(btf1, btf_id);
7559	if (!t1 || !btf_type_is_func(t1))
7560		return -EFAULT;
7561
7562	return btf_check_func_type_match(log, btf1, t1, btf2, t2);
7563}
7564
7565static bool btf_is_dynptr_ptr(const struct btf *btf, const struct btf_type *t)
7566{
7567	const char *name;
7568
7569	t = btf_type_by_id(btf, t->type); /* skip PTR */
7570
7571	while (btf_type_is_modifier(t))
7572		t = btf_type_by_id(btf, t->type);
7573
7574	/* allow either struct or struct forward declaration */
7575	if (btf_type_is_struct(t) ||
7576	    (btf_type_is_fwd(t) && btf_type_kflag(t) == 0)) {
7577		name = btf_str_by_offset(btf, t->name_off);
7578		return name && strcmp(name, "bpf_dynptr") == 0;
7579	}
7580
7581	return false;
7582}
7583
7584struct bpf_cand_cache {
7585	const char *name;
7586	u32 name_len;
7587	u16 kind;
7588	u16 cnt;
7589	struct {
7590		const struct btf *btf;
7591		u32 id;
7592	} cands[];
7593};
7594
7595static DEFINE_MUTEX(cand_cache_mutex);
7596
7597static struct bpf_cand_cache *
7598bpf_core_find_cands(struct bpf_core_ctx *ctx, u32 local_type_id);
7599
7600static int btf_get_ptr_to_btf_id(struct bpf_verifier_log *log, int arg_idx,
7601				 const struct btf *btf, const struct btf_type *t)
7602{
7603	struct bpf_cand_cache *cc;
7604	struct bpf_core_ctx ctx = {
7605		.btf = btf,
7606		.log = log,
7607	};
7608	u32 kern_type_id, type_id;
7609	int err = 0;
7610
7611	/* skip PTR and modifiers */
7612	type_id = t->type;
7613	t = btf_type_by_id(btf, t->type);
7614	while (btf_type_is_modifier(t)) {
7615		type_id = t->type;
7616		t = btf_type_by_id(btf, t->type);
7617	}
7618
7619	mutex_lock(&cand_cache_mutex);
7620	cc = bpf_core_find_cands(&ctx, type_id);
7621	if (IS_ERR(cc)) {
7622		err = PTR_ERR(cc);
7623		bpf_log(log, "arg#%d reference type('%s %s') candidate matching error: %d\n",
7624			arg_idx, btf_type_str(t), __btf_name_by_offset(btf, t->name_off),
7625			err);
7626		goto cand_cache_unlock;
7627	}
7628	if (cc->cnt != 1) {
7629		bpf_log(log, "arg#%d reference type('%s %s') %s\n",
7630			arg_idx, btf_type_str(t), __btf_name_by_offset(btf, t->name_off),
7631			cc->cnt == 0 ? "has no matches" : "is ambiguous");
7632		err = cc->cnt == 0 ? -ENOENT : -ESRCH;
7633		goto cand_cache_unlock;
7634	}
7635	if (btf_is_module(cc->cands[0].btf)) {
7636		bpf_log(log, "arg#%d reference type('%s %s') points to kernel module type (unsupported)\n",
7637			arg_idx, btf_type_str(t), __btf_name_by_offset(btf, t->name_off));
7638		err = -EOPNOTSUPP;
7639		goto cand_cache_unlock;
7640	}
7641	kern_type_id = cc->cands[0].id;
7642
7643cand_cache_unlock:
7644	mutex_unlock(&cand_cache_mutex);
7645	if (err)
7646		return err;
7647
7648	return kern_type_id;
7649}
7650
7651enum btf_arg_tag {
7652	ARG_TAG_CTX	  = BIT_ULL(0),
7653	ARG_TAG_NONNULL   = BIT_ULL(1),
7654	ARG_TAG_TRUSTED   = BIT_ULL(2),
7655	ARG_TAG_UNTRUSTED = BIT_ULL(3),
7656	ARG_TAG_NULLABLE  = BIT_ULL(4),
7657	ARG_TAG_ARENA	  = BIT_ULL(5),
7658};
7659
7660/* Process BTF of a function to produce high-level expectation of function
7661 * arguments (like ARG_PTR_TO_CTX, or ARG_PTR_TO_MEM, etc). This information
7662 * is cached in subprog info for reuse.
7663 * Returns:
7664 * EFAULT - there is a verifier bug. Abort verification.
7665 * EINVAL - cannot convert BTF.
7666 * 0 - Successfully processed BTF and constructed argument expectations.
7667 */
7668int btf_prepare_func_args(struct bpf_verifier_env *env, int subprog)
7669{
7670	bool is_global = subprog_aux(env, subprog)->linkage == BTF_FUNC_GLOBAL;
7671	struct bpf_subprog_info *sub = subprog_info(env, subprog);
7672	struct bpf_verifier_log *log = &env->log;
7673	struct bpf_prog *prog = env->prog;
7674	enum bpf_prog_type prog_type = prog->type;
7675	struct btf *btf = prog->aux->btf;
7676	const struct btf_param *args;
7677	const struct btf_type *t, *ref_t, *fn_t;
7678	u32 i, nargs, btf_id;
7679	const char *tname;
7680
7681	if (sub->args_cached)
7682		return 0;
7683
7684	if (!prog->aux->func_info) {
7685		verifier_bug(env, "func_info undefined");
7686		return -EFAULT;
7687	}
7688
7689	btf_id = prog->aux->func_info[subprog].type_id;
7690	if (!btf_id) {
7691		if (!is_global) /* not fatal for static funcs */
7692			return -EINVAL;
7693		bpf_log(log, "Global functions need valid BTF\n");
7694		return -EFAULT;
7695	}
7696
7697	fn_t = btf_type_by_id(btf, btf_id);
7698	if (!fn_t || !btf_type_is_func(fn_t)) {
7699		/* These checks were already done by the verifier while loading
7700		 * struct bpf_func_info
7701		 */
7702		bpf_log(log, "BTF of func#%d doesn't point to KIND_FUNC\n",
7703			subprog);
7704		return -EFAULT;
7705	}
7706	tname = btf_name_by_offset(btf, fn_t->name_off);
7707
7708	if (prog->aux->func_info_aux[subprog].unreliable) {
7709		verifier_bug(env, "unreliable BTF for function %s()", tname);
7710		return -EFAULT;
7711	}
7712	if (prog_type == BPF_PROG_TYPE_EXT)
7713		prog_type = prog->aux->dst_prog->type;
7714
7715	t = btf_type_by_id(btf, fn_t->type);
7716	if (!t || !btf_type_is_func_proto(t)) {
7717		bpf_log(log, "Invalid type of function %s()\n", tname);
7718		return -EFAULT;
7719	}
7720	args = (const struct btf_param *)(t + 1);
7721	nargs = btf_type_vlen(t);
7722	if (nargs > MAX_BPF_FUNC_REG_ARGS) {
7723		if (!is_global)
7724			return -EINVAL;
7725		bpf_log(log, "Global function %s() with %d > %d args. Buggy compiler.\n",
7726			tname, nargs, MAX_BPF_FUNC_REG_ARGS);
7727		return -EINVAL;
7728	}
7729	/* check that function returns int, exception cb also requires this */
7730	t = btf_type_by_id(btf, t->type);
7731	while (btf_type_is_modifier(t))
7732		t = btf_type_by_id(btf, t->type);
7733	if (!btf_type_is_int(t) && !btf_is_any_enum(t)) {
7734		if (!is_global)
7735			return -EINVAL;
7736		bpf_log(log,
7737			"Global function %s() doesn't return scalar. Only those are supported.\n",
7738			tname);
7739		return -EINVAL;
7740	}
7741	/* Convert BTF function arguments into verifier types.
7742	 * Only PTR_TO_CTX and SCALAR are supported atm.
7743	 */
7744	for (i = 0; i < nargs; i++) {
7745		u32 tags = 0;
7746		int id = 0;
7747
7748		/* 'arg:<tag>' decl_tag takes precedence over derivation of
7749		 * register type from BTF type itself
7750		 */
7751		while ((id = btf_find_next_decl_tag(btf, fn_t, i, "arg:", id)) > 0) {
7752			const struct btf_type *tag_t = btf_type_by_id(btf, id);
7753			const char *tag = __btf_name_by_offset(btf, tag_t->name_off) + 4;
7754
7755			/* disallow arg tags in static subprogs */
7756			if (!is_global) {
7757				bpf_log(log, "arg#%d type tag is not supported in static functions\n", i);
7758				return -EOPNOTSUPP;
7759			}
7760
7761			if (strcmp(tag, "ctx") == 0) {
7762				tags |= ARG_TAG_CTX;
7763			} else if (strcmp(tag, "trusted") == 0) {
7764				tags |= ARG_TAG_TRUSTED;
7765			} else if (strcmp(tag, "untrusted") == 0) {
7766				tags |= ARG_TAG_UNTRUSTED;
7767			} else if (strcmp(tag, "nonnull") == 0) {
7768				tags |= ARG_TAG_NONNULL;
7769			} else if (strcmp(tag, "nullable") == 0) {
7770				tags |= ARG_TAG_NULLABLE;
7771			} else if (strcmp(tag, "arena") == 0) {
7772				tags |= ARG_TAG_ARENA;
7773			} else {
7774				bpf_log(log, "arg#%d has unsupported set of tags\n", i);
7775				return -EOPNOTSUPP;
7776			}
7777		}
7778		if (id != -ENOENT) {
7779			bpf_log(log, "arg#%d type tag fetching failure: %d\n", i, id);
7780			return id;
7781		}
7782
7783		t = btf_type_by_id(btf, args[i].type);
7784		while (btf_type_is_modifier(t))
7785			t = btf_type_by_id(btf, t->type);
7786		if (!btf_type_is_ptr(t))
7787			goto skip_pointer;
7788
7789		if ((tags & ARG_TAG_CTX) || btf_is_prog_ctx_type(log, btf, t, prog_type, i)) {
7790			if (tags & ~ARG_TAG_CTX) {
7791				bpf_log(log, "arg#%d has invalid combination of tags\n", i);
7792				return -EINVAL;
7793			}
7794			if ((tags & ARG_TAG_CTX) &&
7795			    btf_validate_prog_ctx_type(log, btf, t, i, prog_type,
7796						       prog->expected_attach_type))
7797				return -EINVAL;
7798			sub->args[i].arg_type = ARG_PTR_TO_CTX;
7799			continue;
7800		}
7801		if (btf_is_dynptr_ptr(btf, t)) {
7802			if (tags) {
7803				bpf_log(log, "arg#%d has invalid combination of tags\n", i);
7804				return -EINVAL;
7805			}
7806			sub->args[i].arg_type = ARG_PTR_TO_DYNPTR | MEM_RDONLY;
7807			continue;
7808		}
7809		if (tags & ARG_TAG_TRUSTED) {
7810			int kern_type_id;
7811
7812			if (tags & ARG_TAG_NONNULL) {
7813				bpf_log(log, "arg#%d has invalid combination of tags\n", i);
7814				return -EINVAL;
7815			}
7816
7817			kern_type_id = btf_get_ptr_to_btf_id(log, i, btf, t);
7818			if (kern_type_id < 0)
7819				return kern_type_id;
7820
7821			sub->args[i].arg_type = ARG_PTR_TO_BTF_ID | PTR_TRUSTED;
7822			if (tags & ARG_TAG_NULLABLE)
7823				sub->args[i].arg_type |= PTR_MAYBE_NULL;
7824			sub->args[i].btf_id = kern_type_id;
7825			continue;
7826		}
7827		if (tags & ARG_TAG_UNTRUSTED) {
7828			struct btf *vmlinux_btf;
7829			int kern_type_id;
7830
7831			if (tags & ~ARG_TAG_UNTRUSTED) {
7832				bpf_log(log, "arg#%d untrusted cannot be combined with any other tags\n", i);
7833				return -EINVAL;
7834			}
7835
7836			ref_t = btf_type_skip_modifiers(btf, t->type, NULL);
7837			if (btf_type_is_void(ref_t) || btf_type_is_primitive(ref_t)) {
7838				sub->args[i].arg_type = ARG_PTR_TO_MEM | MEM_RDONLY | PTR_UNTRUSTED;
7839				sub->args[i].mem_size = 0;
7840				continue;
7841			}
7842
7843			kern_type_id = btf_get_ptr_to_btf_id(log, i, btf, t);
7844			if (kern_type_id < 0)
7845				return kern_type_id;
7846
7847			vmlinux_btf = bpf_get_btf_vmlinux();
7848			ref_t = btf_type_by_id(vmlinux_btf, kern_type_id);
7849			if (!btf_type_is_struct(ref_t)) {
7850				tname = __btf_name_by_offset(vmlinux_btf, t->name_off);
7851				bpf_log(log, "arg#%d has type %s '%s', but only struct or primitive types are allowed\n",
7852					i, btf_type_str(ref_t), tname);
7853				return -EINVAL;
7854			}
7855			sub->args[i].arg_type = ARG_PTR_TO_BTF_ID | PTR_UNTRUSTED;
7856			sub->args[i].btf_id = kern_type_id;
7857			continue;
7858		}
7859		if (tags & ARG_TAG_ARENA) {
7860			if (tags & ~ARG_TAG_ARENA) {
7861				bpf_log(log, "arg#%d arena cannot be combined with any other tags\n", i);
7862				return -EINVAL;
7863			}
7864			sub->args[i].arg_type = ARG_PTR_TO_ARENA;
7865			continue;
7866		}
7867		if (is_global) { /* generic user data pointer */
7868			u32 mem_size;
7869
7870			if (tags & ARG_TAG_NULLABLE) {
7871				bpf_log(log, "arg#%d has invalid combination of tags\n", i);
7872				return -EINVAL;
7873			}
7874
7875			t = btf_type_skip_modifiers(btf, t->type, NULL);
7876			ref_t = btf_resolve_size(btf, t, &mem_size);
7877			if (IS_ERR(ref_t)) {
7878				bpf_log(log, "arg#%d reference type('%s %s') size cannot be determined: %ld\n",
7879					i, btf_type_str(t), btf_name_by_offset(btf, t->name_off),
7880					PTR_ERR(ref_t));
7881				return -EINVAL;
7882			}
7883
7884			sub->args[i].arg_type = ARG_PTR_TO_MEM | PTR_MAYBE_NULL;
7885			if (tags & ARG_TAG_NONNULL)
7886				sub->args[i].arg_type &= ~PTR_MAYBE_NULL;
7887			sub->args[i].mem_size = mem_size;
7888			continue;
7889		}
7890
7891skip_pointer:
7892		if (tags) {
7893			bpf_log(log, "arg#%d has pointer tag, but is not a pointer type\n", i);
7894			return -EINVAL;
7895		}
7896		if (btf_type_is_int(t) || btf_is_any_enum(t)) {
7897			sub->args[i].arg_type = ARG_ANYTHING;
7898			continue;
7899		}
7900		if (!is_global)
7901			return -EINVAL;
7902		bpf_log(log, "Arg#%d type %s in %s() is not supported yet.\n",
7903			i, btf_type_str(t), tname);
7904		return -EINVAL;
7905	}
7906
7907	sub->arg_cnt = nargs;
7908	sub->args_cached = true;
7909
7910	return 0;
7911}
7912
7913static void btf_type_show(const struct btf *btf, u32 type_id, void *obj,
7914			  struct btf_show *show)
7915{
7916	const struct btf_type *t = btf_type_by_id(btf, type_id);
7917
7918	show->btf = btf;
7919	memset(&show->state, 0, sizeof(show->state));
7920	memset(&show->obj, 0, sizeof(show->obj));
7921
7922	btf_type_ops(t)->show(btf, t, type_id, obj, 0, show);
7923}
7924
7925__printf(2, 0) static void btf_seq_show(struct btf_show *show, const char *fmt,
7926					va_list args)
7927{
7928	seq_vprintf((struct seq_file *)show->target, fmt, args);
7929}
7930
7931int btf_type_seq_show_flags(const struct btf *btf, u32 type_id,
7932			    void *obj, struct seq_file *m, u64 flags)
7933{
7934	struct btf_show sseq;
7935
7936	sseq.target = m;
7937	sseq.showfn = btf_seq_show;
7938	sseq.flags = flags;
7939
7940	btf_type_show(btf, type_id, obj, &sseq);
7941
7942	return sseq.state.status;
7943}
7944
7945void btf_type_seq_show(const struct btf *btf, u32 type_id, void *obj,
7946		       struct seq_file *m)
7947{
7948	(void) btf_type_seq_show_flags(btf, type_id, obj, m,
7949				       BTF_SHOW_NONAME | BTF_SHOW_COMPACT |
7950				       BTF_SHOW_ZERO | BTF_SHOW_UNSAFE);
7951}
7952
7953struct btf_show_snprintf {
7954	struct btf_show show;
7955	int len_left;		/* space left in string */
7956	int len;		/* length we would have written */
7957};
7958
7959__printf(2, 0) static void btf_snprintf_show(struct btf_show *show, const char *fmt,
7960					     va_list args)
7961{
7962	struct btf_show_snprintf *ssnprintf = (struct btf_show_snprintf *)show;
7963	int len;
7964
7965	len = vsnprintf(show->target, ssnprintf->len_left, fmt, args);
7966
7967	if (len < 0) {
7968		ssnprintf->len_left = 0;
7969		ssnprintf->len = len;
7970	} else if (len >= ssnprintf->len_left) {
7971		/* no space, drive on to get length we would have written */
7972		ssnprintf->len_left = 0;
7973		ssnprintf->len += len;
7974	} else {
7975		ssnprintf->len_left -= len;
7976		ssnprintf->len += len;
7977		show->target += len;
7978	}
7979}
7980
7981int btf_type_snprintf_show(const struct btf *btf, u32 type_id, void *obj,
7982			   char *buf, int len, u64 flags)
7983{
7984	struct btf_show_snprintf ssnprintf;
7985
7986	ssnprintf.show.target = buf;
7987	ssnprintf.show.flags = flags;
7988	ssnprintf.show.showfn = btf_snprintf_show;
7989	ssnprintf.len_left = len;
7990	ssnprintf.len = 0;
7991
7992	btf_type_show(btf, type_id, obj, (struct btf_show *)&ssnprintf);
7993
7994	/* If we encountered an error, return it. */
7995	if (ssnprintf.show.state.status)
7996		return ssnprintf.show.state.status;
7997
7998	/* Otherwise return length we would have written */
7999	return ssnprintf.len;
8000}
8001
8002#ifdef CONFIG_PROC_FS
8003static void bpf_btf_show_fdinfo(struct seq_file *m, struct file *filp)
8004{
8005	const struct btf *btf = filp->private_data;
8006
8007	seq_printf(m, "btf_id:\t%u\n", READ_ONCE(btf->id));
8008}
8009#endif
8010
8011static int btf_release(struct inode *inode, struct file *filp)
8012{
8013	btf_put(filp->private_data);
8014	return 0;
8015}
8016
8017const struct file_operations btf_fops = {
8018#ifdef CONFIG_PROC_FS
8019	.show_fdinfo	= bpf_btf_show_fdinfo,
8020#endif
8021	.release	= btf_release,
8022};
8023
8024static int __btf_new_fd(struct btf *btf)
8025{
8026	return anon_inode_getfd("btf", &btf_fops, btf, O_RDONLY | O_CLOEXEC);
8027}
8028
8029int btf_new_fd(const union bpf_attr *attr, bpfptr_t uattr, u32 uattr_size)
8030{
8031	struct btf *btf;
8032	int ret;
8033
8034	btf = btf_parse(attr, uattr, uattr_size);
8035	if (IS_ERR(btf))
8036		return PTR_ERR(btf);
8037
8038	ret = btf_alloc_id(btf);
8039	if (ret) {
8040		btf_free(btf);
8041		return ret;
8042	}
8043
8044	/*
8045	 * The BTF ID is published to the userspace.
8046	 * All BTF free must go through call_rcu() from
8047	 * now on (i.e. free by calling btf_put()).
8048	 */
8049
8050	ret = __btf_new_fd(btf);
8051	if (ret < 0)
8052		btf_put(btf);
8053
8054	return ret;
8055}
8056
8057struct btf *btf_get_by_fd(int fd)
8058{
8059	struct btf *btf;
8060	CLASS(fd, f)(fd);
8061
8062	btf = __btf_get_by_fd(f);
8063	if (!IS_ERR(btf))
8064		refcount_inc(&btf->refcnt);
8065
8066	return btf;
8067}
8068
8069int btf_get_info_by_fd(const struct btf *btf,
8070		       const union bpf_attr *attr,
8071		       union bpf_attr __user *uattr)
8072{
8073	struct bpf_btf_info __user *uinfo;
8074	struct bpf_btf_info info;
8075	u32 info_copy, btf_copy;
8076	void __user *ubtf;
8077	char __user *uname;
8078	u32 uinfo_len, uname_len, name_len;
8079	int ret = 0;
8080
8081	uinfo = u64_to_user_ptr(attr->info.info);
8082	uinfo_len = attr->info.info_len;
8083
8084	info_copy = min_t(u32, uinfo_len, sizeof(info));
8085	memset(&info, 0, sizeof(info));
8086	if (copy_from_user(&info, uinfo, info_copy))
8087		return -EFAULT;
8088
8089	info.id = READ_ONCE(btf->id);
8090	ubtf = u64_to_user_ptr(info.btf);
8091	btf_copy = min_t(u32, btf->data_size, info.btf_size);
8092	if (copy_to_user(ubtf, btf->data, btf_copy))
8093		return -EFAULT;
8094	info.btf_size = btf->data_size;
8095
8096	info.kernel_btf = btf->kernel_btf;
8097
8098	uname = u64_to_user_ptr(info.name);
8099	uname_len = info.name_len;
8100	if (!uname ^ !uname_len)
8101		return -EINVAL;
8102
8103	name_len = strlen(btf->name);
8104	info.name_len = name_len;
8105
8106	if (uname) {
8107		if (uname_len >= name_len + 1) {
8108			if (copy_to_user(uname, btf->name, name_len + 1))
8109				return -EFAULT;
8110		} else {
8111			char zero = '\0';
8112
8113			if (copy_to_user(uname, btf->name, uname_len - 1))
8114				return -EFAULT;
8115			if (put_user(zero, uname + uname_len - 1))
8116				return -EFAULT;
8117			/* let user-space know about too short buffer */
8118			ret = -ENOSPC;
8119		}
8120	}
8121
8122	if (copy_to_user(uinfo, &info, info_copy) ||
8123	    put_user(info_copy, &uattr->info.info_len))
8124		return -EFAULT;
8125
8126	return ret;
8127}
8128
8129int btf_get_fd_by_id(u32 id)
8130{
8131	struct btf *btf;
8132	int fd;
8133
8134	rcu_read_lock();
8135	btf = idr_find(&btf_idr, id);
8136	if (!btf || !refcount_inc_not_zero(&btf->refcnt))
8137		btf = ERR_PTR(-ENOENT);
8138	rcu_read_unlock();
8139
8140	if (IS_ERR(btf))
8141		return PTR_ERR(btf);
8142
8143	fd = __btf_new_fd(btf);
8144	if (fd < 0)
8145		btf_put(btf);
8146
8147	return fd;
8148}
8149
8150u32 btf_obj_id(const struct btf *btf)
8151{
8152	return READ_ONCE(btf->id);
8153}
8154
8155bool btf_is_kernel(const struct btf *btf)
8156{
8157	return btf->kernel_btf;
8158}
8159
8160bool btf_is_module(const struct btf *btf)
8161{
8162	return btf->kernel_btf && strcmp(btf->name, "vmlinux") != 0;
8163}
8164
8165enum {
8166	BTF_MODULE_F_LIVE = (1 << 0),
8167};
8168
8169#ifdef CONFIG_DEBUG_INFO_BTF_MODULES
8170struct btf_module {
8171	struct list_head list;
8172	struct module *module;
8173	struct btf *btf;
8174	struct bin_attribute *sysfs_attr;
8175	int flags;
8176};
8177
8178static LIST_HEAD(btf_modules);
8179static DEFINE_MUTEX(btf_module_mutex);
8180
8181static void purge_cand_cache(struct btf *btf);
8182
8183static int btf_module_notify(struct notifier_block *nb, unsigned long op,
8184			     void *module)
8185{
8186	struct btf_module *btf_mod, *tmp;
8187	struct module *mod = module;
8188	struct btf *btf;
8189	int err = 0;
8190
8191	if (mod->btf_data_size == 0 ||
8192	    (op != MODULE_STATE_COMING && op != MODULE_STATE_LIVE &&
8193	     op != MODULE_STATE_GOING))
8194		goto out;
8195
8196	switch (op) {
8197	case MODULE_STATE_COMING:
8198		btf_mod = kzalloc(sizeof(*btf_mod), GFP_KERNEL);
8199		if (!btf_mod) {
8200			err = -ENOMEM;
8201			goto out;
8202		}
8203		btf = btf_parse_module(mod->name, mod->btf_data, mod->btf_data_size,
8204				       mod->btf_base_data, mod->btf_base_data_size);
8205		if (IS_ERR(btf)) {
8206			kfree(btf_mod);
8207			if (!IS_ENABLED(CONFIG_MODULE_ALLOW_BTF_MISMATCH)) {
8208				pr_warn("failed to validate module [%s] BTF: %ld\n",
8209					mod->name, PTR_ERR(btf));
8210				err = PTR_ERR(btf);
8211			} else {
8212				pr_warn_once("Kernel module BTF mismatch detected, BTF debug info may be unavailable for some modules\n");
8213			}
8214			goto out;
8215		}
8216		err = btf_alloc_id(btf);
8217		if (err) {
8218			btf_free(btf);
8219			kfree(btf_mod);
8220			goto out;
8221		}
8222
8223		purge_cand_cache(NULL);
8224		mutex_lock(&btf_module_mutex);
8225		btf_mod->module = module;
8226		btf_mod->btf = btf;
8227		list_add(&btf_mod->list, &btf_modules);
8228		mutex_unlock(&btf_module_mutex);
8229
8230		if (IS_ENABLED(CONFIG_SYSFS)) {
8231			struct bin_attribute *attr;
8232
8233			attr = kzalloc(sizeof(*attr), GFP_KERNEL);
8234			if (!attr)
8235				goto out;
8236
8237			sysfs_bin_attr_init(attr);
8238			attr->attr.name = btf->name;
8239			attr->attr.mode = 0444;
8240			attr->size = btf->data_size;
8241			attr->private = btf->data;
8242			attr->read = sysfs_bin_attr_simple_read;
8243
8244			err = sysfs_create_bin_file(btf_kobj, attr);
8245			if (err) {
8246				pr_warn("failed to register module [%s] BTF in sysfs: %d\n",
8247					mod->name, err);
8248				kfree(attr);
8249				err = 0;
8250				goto out;
8251			}
8252
8253			btf_mod->sysfs_attr = attr;
8254		}
8255
8256		break;
8257	case MODULE_STATE_LIVE:
8258		mutex_lock(&btf_module_mutex);
8259		list_for_each_entry_safe(btf_mod, tmp, &btf_modules, list) {
8260			if (btf_mod->module != module)
8261				continue;
8262
8263			btf_mod->flags |= BTF_MODULE_F_LIVE;
8264			break;
8265		}
8266		mutex_unlock(&btf_module_mutex);
8267		break;
8268	case MODULE_STATE_GOING:
8269		mutex_lock(&btf_module_mutex);
8270		list_for_each_entry_safe(btf_mod, tmp, &btf_modules, list) {
8271			if (btf_mod->module != module)
8272				continue;
8273
8274			/*
8275			 * For modules, we do the freeing of BTF IDR as soon as
8276			 * module goes away to disable BTF discovery, since the
8277			 * btf_try_get_module() on such BTFs will fail. This may
8278			 * be called again on btf_put(), but it's ok to do so.
8279			 */
8280			btf_free_id(btf_mod->btf);
8281			list_del(&btf_mod->list);
8282			if (btf_mod->sysfs_attr)
8283				sysfs_remove_bin_file(btf_kobj, btf_mod->sysfs_attr);
8284			purge_cand_cache(btf_mod->btf);
8285			btf_put(btf_mod->btf);
8286			kfree(btf_mod->sysfs_attr);
8287			kfree(btf_mod);
8288			break;
8289		}
8290		mutex_unlock(&btf_module_mutex);
8291		break;
8292	}
8293out:
8294	return notifier_from_errno(err);
8295}
8296
8297static struct notifier_block btf_module_nb = {
8298	.notifier_call = btf_module_notify,
8299};
8300
8301static int __init btf_module_init(void)
8302{
8303	register_module_notifier(&btf_module_nb);
8304	return 0;
8305}
8306
8307fs_initcall(btf_module_init);
8308#endif /* CONFIG_DEBUG_INFO_BTF_MODULES */
8309
8310struct module *btf_try_get_module(const struct btf *btf)
8311{
8312	struct module *res = NULL;
8313#ifdef CONFIG_DEBUG_INFO_BTF_MODULES
8314	struct btf_module *btf_mod, *tmp;
8315
8316	mutex_lock(&btf_module_mutex);
8317	list_for_each_entry_safe(btf_mod, tmp, &btf_modules, list) {
8318		if (btf_mod->btf != btf)
8319			continue;
8320
8321		/* We must only consider module whose __init routine has
8322		 * finished, hence we must check for BTF_MODULE_F_LIVE flag,
8323		 * which is set from the notifier callback for
8324		 * MODULE_STATE_LIVE.
8325		 */
8326		if ((btf_mod->flags & BTF_MODULE_F_LIVE) && try_module_get(btf_mod->module))
8327			res = btf_mod->module;
8328
8329		break;
8330	}
8331	mutex_unlock(&btf_module_mutex);
8332#endif
8333
8334	return res;
8335}
8336
8337/* Returns struct btf corresponding to the struct module.
8338 * This function can return NULL or ERR_PTR.
8339 */
8340static struct btf *btf_get_module_btf(const struct module *module)
8341{
8342#ifdef CONFIG_DEBUG_INFO_BTF_MODULES
8343	struct btf_module *btf_mod, *tmp;
8344#endif
8345	struct btf *btf = NULL;
8346
8347	if (!module) {
8348		btf = bpf_get_btf_vmlinux();
8349		if (!IS_ERR_OR_NULL(btf))
8350			btf_get(btf);
8351		return btf;
8352	}
8353
8354#ifdef CONFIG_DEBUG_INFO_BTF_MODULES
8355	mutex_lock(&btf_module_mutex);
8356	list_for_each_entry_safe(btf_mod, tmp, &btf_modules, list) {
8357		if (btf_mod->module != module)
8358			continue;
8359
8360		btf_get(btf_mod->btf);
8361		btf = btf_mod->btf;
8362		break;
8363	}
8364	mutex_unlock(&btf_module_mutex);
8365#endif
8366
8367	return btf;
8368}
8369
8370static int check_btf_kconfigs(const struct module *module, const char *feature)
8371{
8372	if (!module && IS_ENABLED(CONFIG_DEBUG_INFO_BTF)) {
8373		pr_err("missing vmlinux BTF, cannot register %s\n", feature);
8374		return -ENOENT;
8375	}
8376	if (module && IS_ENABLED(CONFIG_DEBUG_INFO_BTF_MODULES))
8377		pr_warn("missing module BTF, cannot register %s\n", feature);
8378	return 0;
8379}
8380
8381BPF_CALL_4(bpf_btf_find_by_name_kind, char *, name, int, name_sz, u32, kind, int, flags)
8382{
8383	struct btf *btf = NULL;
8384	int btf_obj_fd = 0;
8385	long ret;
8386
8387	if (flags)
8388		return -EINVAL;
8389
8390	if (name_sz <= 1 || name[name_sz - 1])
8391		return -EINVAL;
8392
8393	ret = bpf_find_btf_id(name, kind, &btf);
8394	if (ret > 0 && btf_is_module(btf)) {
8395		btf_obj_fd = __btf_new_fd(btf);
8396		if (btf_obj_fd < 0) {
8397			btf_put(btf);
8398			return btf_obj_fd;
8399		}
8400		return ret | (((u64)btf_obj_fd) << 32);
8401	}
8402	if (ret > 0)
8403		btf_put(btf);
8404	return ret;
8405}
8406
8407const struct bpf_func_proto bpf_btf_find_by_name_kind_proto = {
8408	.func		= bpf_btf_find_by_name_kind,
8409	.gpl_only	= false,
8410	.ret_type	= RET_INTEGER,
8411	.arg1_type	= ARG_PTR_TO_MEM | MEM_RDONLY,
8412	.arg2_type	= ARG_CONST_SIZE,
8413	.arg3_type	= ARG_ANYTHING,
8414	.arg4_type	= ARG_ANYTHING,
8415};
8416
8417BTF_ID_LIST_GLOBAL(btf_tracing_ids, MAX_BTF_TRACING_TYPE)
8418#define BTF_TRACING_TYPE(name, type) BTF_ID(struct, type)
8419BTF_TRACING_TYPE_xxx
8420#undef BTF_TRACING_TYPE
8421
8422/* Validate well-formedness of iter argument type.
8423 * On success, return positive BTF ID of iter state's STRUCT type.
8424 * On error, negative error is returned.
8425 */
8426int btf_check_iter_arg(struct btf *btf, const struct btf_type *func, int arg_idx)
8427{
8428	const struct btf_param *arg;
8429	const struct btf_type *t;
8430	const char *name;
8431	int btf_id;
8432
8433	if (btf_type_vlen(func) <= arg_idx)
8434		return -EINVAL;
8435
8436	arg = &btf_params(func)[arg_idx];
8437	t = btf_type_skip_modifiers(btf, arg->type, NULL);
8438	if (!t || !btf_type_is_ptr(t))
8439		return -EINVAL;
8440	t = btf_type_skip_modifiers(btf, t->type, &btf_id);
8441	if (!t || !__btf_type_is_struct(t))
8442		return -EINVAL;
8443
8444	name = btf_name_by_offset(btf, t->name_off);
8445	if (!name || strncmp(name, ITER_PREFIX, sizeof(ITER_PREFIX) - 1))
8446		return -EINVAL;
8447
8448	return btf_id;
8449}
8450
8451static int btf_check_iter_kfuncs(struct btf *btf, const char *func_name,
8452				 const struct btf_type *func, u32 func_flags)
8453{
8454	u32 flags = func_flags & (KF_ITER_NEW | KF_ITER_NEXT | KF_ITER_DESTROY);
8455	const char *sfx, *iter_name;
8456	const struct btf_type *t;
8457	char exp_name[128];
8458	u32 nr_args;
8459	int btf_id;
8460
8461	/* exactly one of KF_ITER_{NEW,NEXT,DESTROY} can be set */
8462	if (!flags || (flags & (flags - 1)))
8463		return -EINVAL;
8464
8465	/* any BPF iter kfunc should have `struct bpf_iter_<type> *` first arg */
8466	nr_args = btf_type_vlen(func);
8467	if (nr_args < 1)
8468		return -EINVAL;
8469
8470	btf_id = btf_check_iter_arg(btf, func, 0);
8471	if (btf_id < 0)
8472		return btf_id;
8473
8474	/* sizeof(struct bpf_iter_<type>) should be a multiple of 8 to
8475	 * fit nicely in stack slots
8476	 */
8477	t = btf_type_by_id(btf, btf_id);
8478	if (t->size == 0 || (t->size % 8))
8479		return -EINVAL;
8480
8481	/* validate bpf_iter_<type>_{new,next,destroy}(struct bpf_iter_<type> *)
8482	 * naming pattern
8483	 */
8484	iter_name = btf_name_by_offset(btf, t->name_off) + sizeof(ITER_PREFIX) - 1;
8485	if (flags & KF_ITER_NEW)
8486		sfx = "new";
8487	else if (flags & KF_ITER_NEXT)
8488		sfx = "next";
8489	else /* (flags & KF_ITER_DESTROY) */
8490		sfx = "destroy";
8491
8492	snprintf(exp_name, sizeof(exp_name), "bpf_iter_%s_%s", iter_name, sfx);
8493	if (strcmp(func_name, exp_name))
8494		return -EINVAL;
8495
8496	/* only iter constructor should have extra arguments */
8497	if (!(flags & KF_ITER_NEW) && nr_args != 1)
8498		return -EINVAL;
8499
8500	if (flags & KF_ITER_NEXT) {
8501		/* bpf_iter_<type>_next() should return pointer */
8502		t = btf_type_skip_modifiers(btf, func->type, NULL);
8503		if (!t || !btf_type_is_ptr(t))
8504			return -EINVAL;
8505	}
8506
8507	if (flags & KF_ITER_DESTROY) {
8508		/* bpf_iter_<type>_destroy() should return void */
8509		t = btf_type_by_id(btf, func->type);
8510		if (!t || !btf_type_is_void(t))
8511			return -EINVAL;
8512	}
8513
8514	return 0;
8515}
8516
8517static int btf_check_kfunc_protos(struct btf *btf, u32 func_id, u32 func_flags)
8518{
8519	const struct btf_type *func;
8520	const char *func_name;
8521	int err;
8522
8523	/* any kfunc should be FUNC -> FUNC_PROTO */
8524	func = btf_type_by_id(btf, func_id);
8525	if (!func || !btf_type_is_func(func))
8526		return -EINVAL;
8527
8528	/* sanity check kfunc name */
8529	func_name = btf_name_by_offset(btf, func->name_off);
8530	if (!func_name || !func_name[0])
8531		return -EINVAL;
8532
8533	func = btf_type_by_id(btf, func->type);
8534	if (!func || !btf_type_is_func_proto(func))
8535		return -EINVAL;
8536
8537	if (func_flags & (KF_ITER_NEW | KF_ITER_NEXT | KF_ITER_DESTROY)) {
8538		err = btf_check_iter_kfuncs(btf, func_name, func, func_flags);
8539		if (err)
8540			return err;
8541	}
8542
8543	return 0;
8544}
8545
8546/* Kernel Function (kfunc) BTF ID set registration API */
8547
8548static int btf_populate_kfunc_set(struct btf *btf, enum btf_kfunc_hook hook,
8549				  const struct btf_kfunc_id_set *kset)
8550{
8551	struct btf_kfunc_hook_filter *hook_filter;
8552	struct btf_id_set8 *add_set = kset->set;
8553	bool vmlinux_set = !btf_is_module(btf);
8554	bool add_filter = !!kset->filter;
8555	struct btf_kfunc_set_tab *tab;
8556	struct btf_id_set8 *set;
8557	u32 set_cnt, i;
8558	int ret;
8559
8560	if (hook >= BTF_KFUNC_HOOK_MAX) {
8561		ret = -EINVAL;
8562		goto end;
8563	}
8564
8565	if (!add_set->cnt)
8566		return 0;
8567
8568	tab = btf->kfunc_set_tab;
8569
8570	if (tab && add_filter) {
8571		u32 i;
8572
8573		hook_filter = &tab->hook_filters[hook];
8574		for (i = 0; i < hook_filter->nr_filters; i++) {
8575			if (hook_filter->filters[i] == kset->filter) {
8576				add_filter = false;
8577				break;
8578			}
8579		}
8580
8581		if (add_filter && hook_filter->nr_filters == BTF_KFUNC_FILTER_MAX_CNT) {
8582			ret = -E2BIG;
8583			goto end;
8584		}
8585	}
8586
8587	if (!tab) {
8588		tab = kzalloc(sizeof(*tab), GFP_KERNEL | __GFP_NOWARN);
8589		if (!tab)
8590			return -ENOMEM;
8591		btf->kfunc_set_tab = tab;
8592	}
8593
8594	set = tab->sets[hook];
8595	/* Warn when register_btf_kfunc_id_set is called twice for the same hook
8596	 * for module sets.
8597	 */
8598	if (WARN_ON_ONCE(set && !vmlinux_set)) {
8599		ret = -EINVAL;
8600		goto end;
8601	}
8602
8603	/* In case of vmlinux sets, there may be more than one set being
8604	 * registered per hook. To create a unified set, we allocate a new set
8605	 * and concatenate all individual sets being registered. While each set
8606	 * is individually sorted, they may become unsorted when concatenated,
8607	 * hence re-sorting the final set again is required to make binary
8608	 * searching the set using btf_id_set8_contains function work.
8609	 *
8610	 * For module sets, we need to allocate as we may need to relocate
8611	 * BTF ids.
8612	 */
8613	set_cnt = set ? set->cnt : 0;
8614
8615	if (set_cnt > U32_MAX - add_set->cnt) {
8616		ret = -EOVERFLOW;
8617		goto end;
8618	}
8619
8620	if (set_cnt + add_set->cnt > BTF_KFUNC_SET_MAX_CNT) {
8621		ret = -E2BIG;
8622		goto end;
8623	}
8624
8625	/* Grow set */
8626	set = krealloc(tab->sets[hook],
8627		       struct_size(set, pairs, set_cnt + add_set->cnt),
8628		       GFP_KERNEL | __GFP_NOWARN);
8629	if (!set) {
8630		ret = -ENOMEM;
8631		goto end;
8632	}
8633
8634	/* For newly allocated set, initialize set->cnt to 0 */
8635	if (!tab->sets[hook])
8636		set->cnt = 0;
8637	tab->sets[hook] = set;
8638
8639	/* Concatenate the two sets */
8640	memcpy(set->pairs + set->cnt, add_set->pairs, add_set->cnt * sizeof(set->pairs[0]));
8641	/* Now that the set is copied, update with relocated BTF ids */
8642	for (i = set->cnt; i < set->cnt + add_set->cnt; i++)
8643		set->pairs[i].id = btf_relocate_id(btf, set->pairs[i].id);
8644
8645	set->cnt += add_set->cnt;
8646
8647	sort(set->pairs, set->cnt, sizeof(set->pairs[0]), btf_id_cmp_func, NULL);
8648
8649	if (add_filter) {
8650		hook_filter = &tab->hook_filters[hook];
8651		hook_filter->filters[hook_filter->nr_filters++] = kset->filter;
8652	}
8653	return 0;
8654end:
8655	btf_free_kfunc_set_tab(btf);
8656	return ret;
8657}
8658
8659static u32 *__btf_kfunc_id_set_contains(const struct btf *btf,
8660					enum btf_kfunc_hook hook,
8661					u32 kfunc_btf_id,
8662					const struct bpf_prog *prog)
8663{
8664	struct btf_kfunc_hook_filter *hook_filter;
8665	struct btf_id_set8 *set;
8666	u32 *id, i;
8667
8668	if (hook >= BTF_KFUNC_HOOK_MAX)
8669		return NULL;
8670	if (!btf->kfunc_set_tab)
8671		return NULL;
8672	hook_filter = &btf->kfunc_set_tab->hook_filters[hook];
8673	for (i = 0; i < hook_filter->nr_filters; i++) {
8674		if (hook_filter->filters[i](prog, kfunc_btf_id))
8675			return NULL;
8676	}
8677	set = btf->kfunc_set_tab->sets[hook];
8678	if (!set)
8679		return NULL;
8680	id = btf_id_set8_contains(set, kfunc_btf_id);
8681	if (!id)
8682		return NULL;
8683	/* The flags for BTF ID are located next to it */
8684	return id + 1;
8685}
8686
8687static int bpf_prog_type_to_kfunc_hook(enum bpf_prog_type prog_type)
8688{
8689	switch (prog_type) {
8690	case BPF_PROG_TYPE_UNSPEC:
8691		return BTF_KFUNC_HOOK_COMMON;
8692	case BPF_PROG_TYPE_XDP:
8693		return BTF_KFUNC_HOOK_XDP;
8694	case BPF_PROG_TYPE_SCHED_CLS:
8695		return BTF_KFUNC_HOOK_TC;
8696	case BPF_PROG_TYPE_STRUCT_OPS:
8697		return BTF_KFUNC_HOOK_STRUCT_OPS;
8698	case BPF_PROG_TYPE_TRACING:
8699	case BPF_PROG_TYPE_TRACEPOINT:
8700	case BPF_PROG_TYPE_PERF_EVENT:
8701	case BPF_PROG_TYPE_LSM:
8702		return BTF_KFUNC_HOOK_TRACING;
8703	case BPF_PROG_TYPE_SYSCALL:
8704		return BTF_KFUNC_HOOK_SYSCALL;
8705	case BPF_PROG_TYPE_CGROUP_SKB:
8706	case BPF_PROG_TYPE_CGROUP_SOCK:
8707	case BPF_PROG_TYPE_CGROUP_DEVICE:
8708	case BPF_PROG_TYPE_CGROUP_SOCK_ADDR:
8709	case BPF_PROG_TYPE_CGROUP_SOCKOPT:
8710	case BPF_PROG_TYPE_CGROUP_SYSCTL:
8711	case BPF_PROG_TYPE_SOCK_OPS:
8712		return BTF_KFUNC_HOOK_CGROUP;
8713	case BPF_PROG_TYPE_SCHED_ACT:
8714		return BTF_KFUNC_HOOK_SCHED_ACT;
8715	case BPF_PROG_TYPE_SK_SKB:
8716		return BTF_KFUNC_HOOK_SK_SKB;
8717	case BPF_PROG_TYPE_SOCKET_FILTER:
8718		return BTF_KFUNC_HOOK_SOCKET_FILTER;
8719	case BPF_PROG_TYPE_LWT_OUT:
8720	case BPF_PROG_TYPE_LWT_IN:
8721	case BPF_PROG_TYPE_LWT_XMIT:
8722	case BPF_PROG_TYPE_LWT_SEG6LOCAL:
8723		return BTF_KFUNC_HOOK_LWT;
8724	case BPF_PROG_TYPE_NETFILTER:
8725		return BTF_KFUNC_HOOK_NETFILTER;
8726	case BPF_PROG_TYPE_KPROBE:
8727		return BTF_KFUNC_HOOK_KPROBE;
8728	default:
8729		return BTF_KFUNC_HOOK_MAX;
8730	}
8731}
8732
8733/* Caution:
8734 * Reference to the module (obtained using btf_try_get_module) corresponding to
8735 * the struct btf *MUST* be held when calling this function from verifier
8736 * context. This is usually true as we stash references in prog's kfunc_btf_tab;
8737 * keeping the reference for the duration of the call provides the necessary
8738 * protection for looking up a well-formed btf->kfunc_set_tab.
8739 */
8740u32 *btf_kfunc_id_set_contains(const struct btf *btf,
8741			       u32 kfunc_btf_id,
8742			       const struct bpf_prog *prog)
8743{
8744	enum bpf_prog_type prog_type = resolve_prog_type(prog);
8745	enum btf_kfunc_hook hook;
8746	u32 *kfunc_flags;
8747
8748	kfunc_flags = __btf_kfunc_id_set_contains(btf, BTF_KFUNC_HOOK_COMMON, kfunc_btf_id, prog);
8749	if (kfunc_flags)
8750		return kfunc_flags;
8751
8752	hook = bpf_prog_type_to_kfunc_hook(prog_type);
8753	return __btf_kfunc_id_set_contains(btf, hook, kfunc_btf_id, prog);
8754}
8755
8756u32 *btf_kfunc_is_modify_return(const struct btf *btf, u32 kfunc_btf_id,
8757				const struct bpf_prog *prog)
8758{
8759	return __btf_kfunc_id_set_contains(btf, BTF_KFUNC_HOOK_FMODRET, kfunc_btf_id, prog);
8760}
8761
8762static int __register_btf_kfunc_id_set(enum btf_kfunc_hook hook,
8763				       const struct btf_kfunc_id_set *kset)
8764{
8765	struct btf *btf;
8766	int ret, i;
8767
8768	btf = btf_get_module_btf(kset->owner);
8769	if (!btf)
8770		return check_btf_kconfigs(kset->owner, "kfunc");
8771	if (IS_ERR(btf))
8772		return PTR_ERR(btf);
8773
8774	for (i = 0; i < kset->set->cnt; i++) {
8775		ret = btf_check_kfunc_protos(btf, btf_relocate_id(btf, kset->set->pairs[i].id),
8776					     kset->set->pairs[i].flags);
8777		if (ret)
8778			goto err_out;
8779	}
8780
8781	ret = btf_populate_kfunc_set(btf, hook, kset);
8782
8783err_out:
8784	btf_put(btf);
8785	return ret;
8786}
8787
8788/* This function must be invoked only from initcalls/module init functions */
8789int register_btf_kfunc_id_set(enum bpf_prog_type prog_type,
8790			      const struct btf_kfunc_id_set *kset)
8791{
8792	enum btf_kfunc_hook hook;
8793
8794	/* All kfuncs need to be tagged as such in BTF.
8795	 * WARN() for initcall registrations that do not check errors.
8796	 */
8797	if (!(kset->set->flags & BTF_SET8_KFUNCS)) {
8798		WARN_ON(!kset->owner);
8799		return -EINVAL;
8800	}
8801
8802	hook = bpf_prog_type_to_kfunc_hook(prog_type);
8803	return __register_btf_kfunc_id_set(hook, kset);
8804}
8805EXPORT_SYMBOL_GPL(register_btf_kfunc_id_set);
8806
8807/* This function must be invoked only from initcalls/module init functions */
8808int register_btf_fmodret_id_set(const struct btf_kfunc_id_set *kset)
8809{
8810	return __register_btf_kfunc_id_set(BTF_KFUNC_HOOK_FMODRET, kset);
8811}
8812EXPORT_SYMBOL_GPL(register_btf_fmodret_id_set);
8813
8814s32 btf_find_dtor_kfunc(struct btf *btf, u32 btf_id)
8815{
8816	struct btf_id_dtor_kfunc_tab *tab = btf->dtor_kfunc_tab;
8817	struct btf_id_dtor_kfunc *dtor;
8818
8819	if (!tab)
8820		return -ENOENT;
8821	/* Even though the size of tab->dtors[0] is > sizeof(u32), we only need
8822	 * to compare the first u32 with btf_id, so we can reuse btf_id_cmp_func.
8823	 */
8824	BUILD_BUG_ON(offsetof(struct btf_id_dtor_kfunc, btf_id) != 0);
8825	dtor = bsearch(&btf_id, tab->dtors, tab->cnt, sizeof(tab->dtors[0]), btf_id_cmp_func);
8826	if (!dtor)
8827		return -ENOENT;
8828	return dtor->kfunc_btf_id;
8829}
8830
8831static int btf_check_dtor_kfuncs(struct btf *btf, const struct btf_id_dtor_kfunc *dtors, u32 cnt)
8832{
8833	const struct btf_type *dtor_func, *dtor_func_proto, *t;
8834	const struct btf_param *args;
8835	s32 dtor_btf_id;
8836	u32 nr_args, i;
8837
8838	for (i = 0; i < cnt; i++) {
8839		dtor_btf_id = btf_relocate_id(btf, dtors[i].kfunc_btf_id);
8840
8841		dtor_func = btf_type_by_id(btf, dtor_btf_id);
8842		if (!dtor_func || !btf_type_is_func(dtor_func))
8843			return -EINVAL;
8844
8845		dtor_func_proto = btf_type_by_id(btf, dtor_func->type);
8846		if (!dtor_func_proto || !btf_type_is_func_proto(dtor_func_proto))
8847			return -EINVAL;
8848
8849		/* Make sure the prototype of the destructor kfunc is 'void func(type *)' */
8850		t = btf_type_by_id(btf, dtor_func_proto->type);
8851		if (!t || !btf_type_is_void(t))
8852			return -EINVAL;
8853
8854		nr_args = btf_type_vlen(dtor_func_proto);
8855		if (nr_args != 1)
8856			return -EINVAL;
8857		args = btf_params(dtor_func_proto);
8858		t = btf_type_by_id(btf, args[0].type);
8859		/* Allow any pointer type, as width on targets Linux supports
8860		 * will be same for all pointer types (i.e. sizeof(void *))
8861		 */
8862		if (!t || !btf_type_is_ptr(t))
8863			return -EINVAL;
8864	}
8865	return 0;
8866}
8867
8868/* This function must be invoked only from initcalls/module init functions */
8869int register_btf_id_dtor_kfuncs(const struct btf_id_dtor_kfunc *dtors, u32 add_cnt,
8870				struct module *owner)
8871{
8872	struct btf_id_dtor_kfunc_tab *tab;
8873	struct btf *btf;
8874	u32 tab_cnt, i;
8875	int ret;
8876
8877	btf = btf_get_module_btf(owner);
8878	if (!btf)
8879		return check_btf_kconfigs(owner, "dtor kfuncs");
8880	if (IS_ERR(btf))
8881		return PTR_ERR(btf);
8882
8883	if (add_cnt >= BTF_DTOR_KFUNC_MAX_CNT) {
8884		pr_err("cannot register more than %d kfunc destructors\n", BTF_DTOR_KFUNC_MAX_CNT);
8885		ret = -E2BIG;
8886		goto end;
8887	}
8888
8889	/* Ensure that the prototype of dtor kfuncs being registered is sane */
8890	ret = btf_check_dtor_kfuncs(btf, dtors, add_cnt);
8891	if (ret < 0)
8892		goto end;
8893
8894	tab = btf->dtor_kfunc_tab;
8895	/* Only one call allowed for modules */
8896	if (WARN_ON_ONCE(tab && btf_is_module(btf))) {
8897		ret = -EINVAL;
8898		goto end;
8899	}
8900
8901	tab_cnt = tab ? tab->cnt : 0;
8902	if (tab_cnt > U32_MAX - add_cnt) {
8903		ret = -EOVERFLOW;
8904		goto end;
8905	}
8906	if (tab_cnt + add_cnt >= BTF_DTOR_KFUNC_MAX_CNT) {
8907		pr_err("cannot register more than %d kfunc destructors\n", BTF_DTOR_KFUNC_MAX_CNT);
8908		ret = -E2BIG;
8909		goto end;
8910	}
8911
8912	tab = krealloc(btf->dtor_kfunc_tab,
8913		       struct_size(tab, dtors, tab_cnt + add_cnt),
8914		       GFP_KERNEL | __GFP_NOWARN);
8915	if (!tab) {
8916		ret = -ENOMEM;
8917		goto end;
8918	}
8919
8920	if (!btf->dtor_kfunc_tab)
8921		tab->cnt = 0;
8922	btf->dtor_kfunc_tab = tab;
8923
8924	memcpy(tab->dtors + tab->cnt, dtors, add_cnt * sizeof(tab->dtors[0]));
8925
8926	/* remap BTF ids based on BTF relocation (if any) */
8927	for (i = tab_cnt; i < tab_cnt + add_cnt; i++) {
8928		tab->dtors[i].btf_id = btf_relocate_id(btf, tab->dtors[i].btf_id);
8929		tab->dtors[i].kfunc_btf_id = btf_relocate_id(btf, tab->dtors[i].kfunc_btf_id);
8930	}
8931
8932	tab->cnt += add_cnt;
8933
8934	sort(tab->dtors, tab->cnt, sizeof(tab->dtors[0]), btf_id_cmp_func, NULL);
8935
8936end:
8937	if (ret)
8938		btf_free_dtor_kfunc_tab(btf);
8939	btf_put(btf);
8940	return ret;
8941}
8942EXPORT_SYMBOL_GPL(register_btf_id_dtor_kfuncs);
8943
8944#define MAX_TYPES_ARE_COMPAT_DEPTH 2
8945
8946/* Check local and target types for compatibility. This check is used for
8947 * type-based CO-RE relocations and follow slightly different rules than
8948 * field-based relocations. This function assumes that root types were already
8949 * checked for name match. Beyond that initial root-level name check, names
8950 * are completely ignored. Compatibility rules are as follows:
8951 *   - any two STRUCTs/UNIONs/FWDs/ENUMs/INTs/ENUM64s are considered compatible, but
8952 *     kind should match for local and target types (i.e., STRUCT is not
8953 *     compatible with UNION);
8954 *   - for ENUMs/ENUM64s, the size is ignored;
8955 *   - for INT, size and signedness are ignored;
8956 *   - for ARRAY, dimensionality is ignored, element types are checked for
8957 *     compatibility recursively;
8958 *   - CONST/VOLATILE/RESTRICT modifiers are ignored;
8959 *   - TYPEDEFs/PTRs are compatible if types they pointing to are compatible;
8960 *   - FUNC_PROTOs are compatible if they have compatible signature: same
8961 *     number of input args and compatible return and argument types.
8962 * These rules are not set in stone and probably will be adjusted as we get
8963 * more experience with using BPF CO-RE relocations.
8964 */
8965int bpf_core_types_are_compat(const struct btf *local_btf, __u32 local_id,
8966			      const struct btf *targ_btf, __u32 targ_id)
8967{
8968	return __bpf_core_types_are_compat(local_btf, local_id, targ_btf, targ_id,
8969					   MAX_TYPES_ARE_COMPAT_DEPTH);
8970}
8971
8972#define MAX_TYPES_MATCH_DEPTH 2
8973
8974int bpf_core_types_match(const struct btf *local_btf, u32 local_id,
8975			 const struct btf *targ_btf, u32 targ_id)
8976{
8977	return __bpf_core_types_match(local_btf, local_id, targ_btf, targ_id, false,
8978				      MAX_TYPES_MATCH_DEPTH);
8979}
8980
8981static bool bpf_core_is_flavor_sep(const char *s)
8982{
8983	/* check X___Y name pattern, where X and Y are not underscores */
8984	return s[0] != '_' &&				      /* X */
8985	       s[1] == '_' && s[2] == '_' && s[3] == '_' &&   /* ___ */
8986	       s[4] != '_';				      /* Y */
8987}
8988
8989size_t bpf_core_essential_name_len(const char *name)
8990{
8991	size_t n = strlen(name);
8992	int i;
8993
8994	for (i = n - 5; i >= 0; i--) {
8995		if (bpf_core_is_flavor_sep(name + i))
8996			return i + 1;
8997	}
8998	return n;
8999}
9000
9001static void bpf_free_cands(struct bpf_cand_cache *cands)
9002{
9003	if (!cands->cnt)
9004		/* empty candidate array was allocated on stack */
9005		return;
9006	kfree(cands);
9007}
9008
9009static void bpf_free_cands_from_cache(struct bpf_cand_cache *cands)
9010{
9011	kfree(cands->name);
9012	kfree(cands);
9013}
9014
9015#define VMLINUX_CAND_CACHE_SIZE 31
9016static struct bpf_cand_cache *vmlinux_cand_cache[VMLINUX_CAND_CACHE_SIZE];
9017
9018#define MODULE_CAND_CACHE_SIZE 31
9019static struct bpf_cand_cache *module_cand_cache[MODULE_CAND_CACHE_SIZE];
9020
9021static void __print_cand_cache(struct bpf_verifier_log *log,
9022			       struct bpf_cand_cache **cache,
9023			       int cache_size)
9024{
9025	struct bpf_cand_cache *cc;
9026	int i, j;
9027
9028	for (i = 0; i < cache_size; i++) {
9029		cc = cache[i];
9030		if (!cc)
9031			continue;
9032		bpf_log(log, "[%d]%s(", i, cc->name);
9033		for (j = 0; j < cc->cnt; j++) {
9034			bpf_log(log, "%d", cc->cands[j].id);
9035			if (j < cc->cnt - 1)
9036				bpf_log(log, " ");
9037		}
9038		bpf_log(log, "), ");
9039	}
9040}
9041
9042static void print_cand_cache(struct bpf_verifier_log *log)
9043{
9044	mutex_lock(&cand_cache_mutex);
9045	bpf_log(log, "vmlinux_cand_cache:");
9046	__print_cand_cache(log, vmlinux_cand_cache, VMLINUX_CAND_CACHE_SIZE);
9047	bpf_log(log, "\nmodule_cand_cache:");
9048	__print_cand_cache(log, module_cand_cache, MODULE_CAND_CACHE_SIZE);
9049	bpf_log(log, "\n");
9050	mutex_unlock(&cand_cache_mutex);
9051}
9052
9053static u32 hash_cands(struct bpf_cand_cache *cands)
9054{
9055	return jhash(cands->name, cands->name_len, 0);
9056}
9057
9058static struct bpf_cand_cache *check_cand_cache(struct bpf_cand_cache *cands,
9059					       struct bpf_cand_cache **cache,
9060					       int cache_size)
9061{
9062	struct bpf_cand_cache *cc = cache[hash_cands(cands) % cache_size];
9063
9064	if (cc && cc->name_len == cands->name_len &&
9065	    !strncmp(cc->name, cands->name, cands->name_len))
9066		return cc;
9067	return NULL;
9068}
9069
9070static size_t sizeof_cands(int cnt)
9071{
9072	return offsetof(struct bpf_cand_cache, cands[cnt]);
9073}
9074
9075static struct bpf_cand_cache *populate_cand_cache(struct bpf_cand_cache *cands,
9076						  struct bpf_cand_cache **cache,
9077						  int cache_size)
9078{
9079	struct bpf_cand_cache **cc = &cache[hash_cands(cands) % cache_size], *new_cands;
9080
9081	if (*cc) {
9082		bpf_free_cands_from_cache(*cc);
9083		*cc = NULL;
9084	}
9085	new_cands = kmemdup(cands, sizeof_cands(cands->cnt), GFP_KERNEL_ACCOUNT);
9086	if (!new_cands) {
9087		bpf_free_cands(cands);
9088		return ERR_PTR(-ENOMEM);
9089	}
9090	/* strdup the name, since it will stay in cache.
9091	 * the cands->name points to strings in prog's BTF and the prog can be unloaded.
9092	 */
9093	new_cands->name = kmemdup_nul(cands->name, cands->name_len, GFP_KERNEL_ACCOUNT);
9094	bpf_free_cands(cands);
9095	if (!new_cands->name) {
9096		kfree(new_cands);
9097		return ERR_PTR(-ENOMEM);
9098	}
9099	*cc = new_cands;
9100	return new_cands;
9101}
9102
9103#ifdef CONFIG_DEBUG_INFO_BTF_MODULES
9104static void __purge_cand_cache(struct btf *btf, struct bpf_cand_cache **cache,
9105			       int cache_size)
9106{
9107	struct bpf_cand_cache *cc;
9108	int i, j;
9109
9110	for (i = 0; i < cache_size; i++) {
9111		cc = cache[i];
9112		if (!cc)
9113			continue;
9114		if (!btf) {
9115			/* when new module is loaded purge all of module_cand_cache,
9116			 * since new module might have candidates with the name
9117			 * that matches cached cands.
9118			 */
9119			bpf_free_cands_from_cache(cc);
9120			cache[i] = NULL;
9121			continue;
9122		}
9123		/* when module is unloaded purge cache entries
9124		 * that match module's btf
9125		 */
9126		for (j = 0; j < cc->cnt; j++)
9127			if (cc->cands[j].btf == btf) {
9128				bpf_free_cands_from_cache(cc);
9129				cache[i] = NULL;
9130				break;
9131			}
9132	}
9133
9134}
9135
9136static void purge_cand_cache(struct btf *btf)
9137{
9138	mutex_lock(&cand_cache_mutex);
9139	__purge_cand_cache(btf, module_cand_cache, MODULE_CAND_CACHE_SIZE);
9140	mutex_unlock(&cand_cache_mutex);
9141}
9142#endif
9143
9144static struct bpf_cand_cache *
9145bpf_core_add_cands(struct bpf_cand_cache *cands, const struct btf *targ_btf,
9146		   int targ_start_id)
9147{
9148	struct bpf_cand_cache *new_cands;
9149	const struct btf_type *t;
9150	const char *targ_name;
9151	size_t targ_essent_len;
9152	int n, i;
9153
9154	n = btf_nr_types(targ_btf);
9155	for (i = targ_start_id; i < n; i++) {
9156		t = btf_type_by_id(targ_btf, i);
9157		if (btf_kind(t) != cands->kind)
9158			continue;
9159
9160		targ_name = btf_name_by_offset(targ_btf, t->name_off);
9161		if (!targ_name)
9162			continue;
9163
9164		/* the resched point is before strncmp to make sure that search
9165		 * for non-existing name will have a chance to schedule().
9166		 */
9167		cond_resched();
9168
9169		if (strncmp(cands->name, targ_name, cands->name_len) != 0)
9170			continue;
9171
9172		targ_essent_len = bpf_core_essential_name_len(targ_name);
9173		if (targ_essent_len != cands->name_len)
9174			continue;
9175
9176		/* most of the time there is only one candidate for a given kind+name pair */
9177		new_cands = kmalloc(sizeof_cands(cands->cnt + 1), GFP_KERNEL_ACCOUNT);
9178		if (!new_cands) {
9179			bpf_free_cands(cands);
9180			return ERR_PTR(-ENOMEM);
9181		}
9182
9183		memcpy(new_cands, cands, sizeof_cands(cands->cnt));
9184		bpf_free_cands(cands);
9185		cands = new_cands;
9186		cands->cands[cands->cnt].btf = targ_btf;
9187		cands->cands[cands->cnt].id = i;
9188		cands->cnt++;
9189	}
9190	return cands;
9191}
9192
9193static struct bpf_cand_cache *
9194bpf_core_find_cands(struct bpf_core_ctx *ctx, u32 local_type_id)
9195{
9196	struct bpf_cand_cache *cands, *cc, local_cand = {};
9197	const struct btf *local_btf = ctx->btf;
9198	const struct btf_type *local_type;
9199	const struct btf *main_btf;
9200	size_t local_essent_len;
9201	struct btf *mod_btf;
9202	const char *name;
9203	int id;
9204
9205	main_btf = bpf_get_btf_vmlinux();
9206	if (IS_ERR(main_btf))
9207		return ERR_CAST(main_btf);
9208	if (!main_btf)
9209		return ERR_PTR(-EINVAL);
9210
9211	local_type = btf_type_by_id(local_btf, local_type_id);
9212	if (!local_type)
9213		return ERR_PTR(-EINVAL);
9214
9215	name = btf_name_by_offset(local_btf, local_type->name_off);
9216	if (str_is_empty(name))
9217		return ERR_PTR(-EINVAL);
9218	local_essent_len = bpf_core_essential_name_len(name);
9219
9220	cands = &local_cand;
9221	cands->name = name;
9222	cands->kind = btf_kind(local_type);
9223	cands->name_len = local_essent_len;
9224
9225	cc = check_cand_cache(cands, vmlinux_cand_cache, VMLINUX_CAND_CACHE_SIZE);
9226	/* cands is a pointer to stack here */
9227	if (cc) {
9228		if (cc->cnt)
9229			return cc;
9230		goto check_modules;
9231	}
9232
9233	/* Attempt to find target candidates in vmlinux BTF first */
9234	cands = bpf_core_add_cands(cands, main_btf, 1);
9235	if (IS_ERR(cands))
9236		return ERR_CAST(cands);
9237
9238	/* cands is a pointer to kmalloced memory here if cands->cnt > 0 */
9239
9240	/* populate cache even when cands->cnt == 0 */
9241	cc = populate_cand_cache(cands, vmlinux_cand_cache, VMLINUX_CAND_CACHE_SIZE);
9242	if (IS_ERR(cc))
9243		return ERR_CAST(cc);
9244
9245	/* if vmlinux BTF has any candidate, don't go for module BTFs */
9246	if (cc->cnt)
9247		return cc;
9248
9249check_modules:
9250	/* cands is a pointer to stack here and cands->cnt == 0 */
9251	cc = check_cand_cache(cands, module_cand_cache, MODULE_CAND_CACHE_SIZE);
9252	if (cc)
9253		/* if cache has it return it even if cc->cnt == 0 */
9254		return cc;
9255
9256	/* If candidate is not found in vmlinux's BTF then search in module's BTFs */
9257	spin_lock_bh(&btf_idr_lock);
9258	idr_for_each_entry(&btf_idr, mod_btf, id) {
9259		if (!btf_is_module(mod_btf))
9260			continue;
9261		/* linear search could be slow hence unlock/lock
9262		 * the IDR to avoiding holding it for too long
9263		 */
9264		btf_get(mod_btf);
9265		spin_unlock_bh(&btf_idr_lock);
9266		cands = bpf_core_add_cands(cands, mod_btf, btf_nr_types(main_btf));
9267		btf_put(mod_btf);
9268		if (IS_ERR(cands))
9269			return ERR_CAST(cands);
9270		spin_lock_bh(&btf_idr_lock);
9271	}
9272	spin_unlock_bh(&btf_idr_lock);
9273	/* cands is a pointer to kmalloced memory here if cands->cnt > 0
9274	 * or pointer to stack if cands->cnd == 0.
9275	 * Copy it into the cache even when cands->cnt == 0 and
9276	 * return the result.
9277	 */
9278	return populate_cand_cache(cands, module_cand_cache, MODULE_CAND_CACHE_SIZE);
9279}
9280
9281int bpf_core_apply(struct bpf_core_ctx *ctx, const struct bpf_core_relo *relo,
9282		   int relo_idx, void *insn)
9283{
9284	bool need_cands = relo->kind != BPF_CORE_TYPE_ID_LOCAL;
9285	struct bpf_core_cand_list cands = {};
9286	struct bpf_core_relo_res targ_res;
9287	struct bpf_core_spec *specs;
9288	const struct btf_type *type;
9289	int err;
9290
9291	/* ~4k of temp memory necessary to convert LLVM spec like "0:1:0:5"
9292	 * into arrays of btf_ids of struct fields and array indices.
9293	 */
9294	specs = kcalloc(3, sizeof(*specs), GFP_KERNEL_ACCOUNT);
9295	if (!specs)
9296		return -ENOMEM;
9297
9298	type = btf_type_by_id(ctx->btf, relo->type_id);
9299	if (!type) {
9300		bpf_log(ctx->log, "relo #%u: bad type id %u\n",
9301			relo_idx, relo->type_id);
9302		kfree(specs);
9303		return -EINVAL;
9304	}
9305
9306	if (need_cands) {
9307		struct bpf_cand_cache *cc;
9308		int i;
9309
9310		mutex_lock(&cand_cache_mutex);
9311		cc = bpf_core_find_cands(ctx, relo->type_id);
9312		if (IS_ERR(cc)) {
9313			bpf_log(ctx->log, "target candidate search failed for %d\n",
9314				relo->type_id);
9315			err = PTR_ERR(cc);
9316			goto out;
9317		}
9318		if (cc->cnt) {
9319			cands.cands = kcalloc(cc->cnt, sizeof(*cands.cands), GFP_KERNEL_ACCOUNT);
9320			if (!cands.cands) {
9321				err = -ENOMEM;
9322				goto out;
9323			}
9324		}
9325		for (i = 0; i < cc->cnt; i++) {
9326			bpf_log(ctx->log,
9327				"CO-RE relocating %s %s: found target candidate [%d]\n",
9328				btf_kind_str[cc->kind], cc->name, cc->cands[i].id);
9329			cands.cands[i].btf = cc->cands[i].btf;
9330			cands.cands[i].id = cc->cands[i].id;
9331		}
9332		cands.len = cc->cnt;
9333		/* cand_cache_mutex needs to span the cache lookup and
9334		 * copy of btf pointer into bpf_core_cand_list,
9335		 * since module can be unloaded while bpf_core_calc_relo_insn
9336		 * is working with module's btf.
9337		 */
9338	}
9339
9340	err = bpf_core_calc_relo_insn((void *)ctx->log, relo, relo_idx, ctx->btf, &cands, specs,
9341				      &targ_res);
9342	if (err)
9343		goto out;
9344
9345	err = bpf_core_patch_insn((void *)ctx->log, insn, relo->insn_off / 8, relo, relo_idx,
9346				  &targ_res);
9347
9348out:
9349	kfree(specs);
9350	if (need_cands) {
9351		kfree(cands.cands);
9352		mutex_unlock(&cand_cache_mutex);
9353		if (ctx->log->level & BPF_LOG_LEVEL2)
9354			print_cand_cache(ctx->log);
9355	}
9356	return err;
9357}
9358
9359bool btf_nested_type_is_trusted(struct bpf_verifier_log *log,
9360				const struct bpf_reg_state *reg,
9361				const char *field_name, u32 btf_id, const char *suffix)
9362{
9363	struct btf *btf = reg->btf;
9364	const struct btf_type *walk_type, *safe_type;
9365	const char *tname;
9366	char safe_tname[64];
9367	long ret, safe_id;
9368	const struct btf_member *member;
9369	u32 i;
9370
9371	walk_type = btf_type_by_id(btf, reg->btf_id);
9372	if (!walk_type)
9373		return false;
9374
9375	tname = btf_name_by_offset(btf, walk_type->name_off);
9376
9377	ret = snprintf(safe_tname, sizeof(safe_tname), "%s%s", tname, suffix);
9378	if (ret >= sizeof(safe_tname))
9379		return false;
9380
9381	safe_id = btf_find_by_name_kind(btf, safe_tname, BTF_INFO_KIND(walk_type->info));
9382	if (safe_id < 0)
9383		return false;
9384
9385	safe_type = btf_type_by_id(btf, safe_id);
9386	if (!safe_type)
9387		return false;
9388
9389	for_each_member(i, safe_type, member) {
9390		const char *m_name = __btf_name_by_offset(btf, member->name_off);
9391		const struct btf_type *mtype = btf_type_by_id(btf, member->type);
9392		u32 id;
9393
9394		if (!btf_type_is_ptr(mtype))
9395			continue;
9396
9397		btf_type_skip_modifiers(btf, mtype->type, &id);
9398		/* If we match on both type and name, the field is considered trusted. */
9399		if (btf_id == id && !strcmp(field_name, m_name))
9400			return true;
9401	}
9402
9403	return false;
9404}
9405
9406bool btf_type_ids_nocast_alias(struct bpf_verifier_log *log,
9407			       const struct btf *reg_btf, u32 reg_id,
9408			       const struct btf *arg_btf, u32 arg_id)
9409{
9410	const char *reg_name, *arg_name, *search_needle;
9411	const struct btf_type *reg_type, *arg_type;
9412	int reg_len, arg_len, cmp_len;
9413	size_t pattern_len = sizeof(NOCAST_ALIAS_SUFFIX) - sizeof(char);
9414
9415	reg_type = btf_type_by_id(reg_btf, reg_id);
9416	if (!reg_type)
9417		return false;
9418
9419	arg_type = btf_type_by_id(arg_btf, arg_id);
9420	if (!arg_type)
9421		return false;
9422
9423	reg_name = btf_name_by_offset(reg_btf, reg_type->name_off);
9424	arg_name = btf_name_by_offset(arg_btf, arg_type->name_off);
9425
9426	reg_len = strlen(reg_name);
9427	arg_len = strlen(arg_name);
9428
9429	/* Exactly one of the two type names may be suffixed with ___init, so
9430	 * if the strings are the same size, they can't possibly be no-cast
9431	 * aliases of one another. If you have two of the same type names, e.g.
9432	 * they're both nf_conn___init, it would be improper to return true
9433	 * because they are _not_ no-cast aliases, they are the same type.
9434	 */
9435	if (reg_len == arg_len)
9436		return false;
9437
9438	/* Either of the two names must be the other name, suffixed with ___init. */
9439	if ((reg_len != arg_len + pattern_len) &&
9440	    (arg_len != reg_len + pattern_len))
9441		return false;
9442
9443	if (reg_len < arg_len) {
9444		search_needle = strstr(arg_name, NOCAST_ALIAS_SUFFIX);
9445		cmp_len = reg_len;
9446	} else {
9447		search_needle = strstr(reg_name, NOCAST_ALIAS_SUFFIX);
9448		cmp_len = arg_len;
9449	}
9450
9451	if (!search_needle)
9452		return false;
9453
9454	/* ___init suffix must come at the end of the name */
9455	if (*(search_needle + pattern_len) != '\0')
9456		return false;
9457
9458	return !strncmp(reg_name, arg_name, cmp_len);
9459}
9460
9461#ifdef CONFIG_BPF_JIT
9462static int
9463btf_add_struct_ops(struct btf *btf, struct bpf_struct_ops *st_ops,
9464		   struct bpf_verifier_log *log)
9465{
9466	struct btf_struct_ops_tab *tab, *new_tab;
9467	int i, err;
9468
9469	tab = btf->struct_ops_tab;
9470	if (!tab) {
9471		tab = kzalloc(struct_size(tab, ops, 4), GFP_KERNEL);
9472		if (!tab)
9473			return -ENOMEM;
9474		tab->capacity = 4;
9475		btf->struct_ops_tab = tab;
9476	}
9477
9478	for (i = 0; i < tab->cnt; i++)
9479		if (tab->ops[i].st_ops == st_ops)
9480			return -EEXIST;
9481
9482	if (tab->cnt == tab->capacity) {
9483		new_tab = krealloc(tab,
9484				   struct_size(tab, ops, tab->capacity * 2),
9485				   GFP_KERNEL);
9486		if (!new_tab)
9487			return -ENOMEM;
9488		tab = new_tab;
9489		tab->capacity *= 2;
9490		btf->struct_ops_tab = tab;
9491	}
9492
9493	tab->ops[btf->struct_ops_tab->cnt].st_ops = st_ops;
9494
9495	err = bpf_struct_ops_desc_init(&tab->ops[btf->struct_ops_tab->cnt], btf, log);
9496	if (err)
9497		return err;
9498
9499	btf->struct_ops_tab->cnt++;
9500
9501	return 0;
9502}
9503
9504const struct bpf_struct_ops_desc *
9505bpf_struct_ops_find_value(struct btf *btf, u32 value_id)
9506{
9507	const struct bpf_struct_ops_desc *st_ops_list;
9508	unsigned int i;
9509	u32 cnt;
9510
9511	if (!value_id)
9512		return NULL;
9513	if (!btf->struct_ops_tab)
9514		return NULL;
9515
9516	cnt = btf->struct_ops_tab->cnt;
9517	st_ops_list = btf->struct_ops_tab->ops;
9518	for (i = 0; i < cnt; i++) {
9519		if (st_ops_list[i].value_id == value_id)
9520			return &st_ops_list[i];
9521	}
9522
9523	return NULL;
9524}
9525
9526const struct bpf_struct_ops_desc *
9527bpf_struct_ops_find(struct btf *btf, u32 type_id)
9528{
9529	const struct bpf_struct_ops_desc *st_ops_list;
9530	unsigned int i;
9531	u32 cnt;
9532
9533	if (!type_id)
9534		return NULL;
9535	if (!btf->struct_ops_tab)
9536		return NULL;
9537
9538	cnt = btf->struct_ops_tab->cnt;
9539	st_ops_list = btf->struct_ops_tab->ops;
9540	for (i = 0; i < cnt; i++) {
9541		if (st_ops_list[i].type_id == type_id)
9542			return &st_ops_list[i];
9543	}
9544
9545	return NULL;
9546}
9547
9548int __register_bpf_struct_ops(struct bpf_struct_ops *st_ops)
9549{
9550	struct bpf_verifier_log *log;
9551	struct btf *btf;
9552	int err = 0;
9553
9554	btf = btf_get_module_btf(st_ops->owner);
9555	if (!btf)
9556		return check_btf_kconfigs(st_ops->owner, "struct_ops");
9557	if (IS_ERR(btf))
9558		return PTR_ERR(btf);
9559
9560	log = kzalloc(sizeof(*log), GFP_KERNEL | __GFP_NOWARN);
9561	if (!log) {
9562		err = -ENOMEM;
9563		goto errout;
9564	}
9565
9566	log->level = BPF_LOG_KERNEL;
9567
9568	err = btf_add_struct_ops(btf, st_ops, log);
9569
9570errout:
9571	kfree(log);
9572	btf_put(btf);
9573
9574	return err;
9575}
9576EXPORT_SYMBOL_GPL(__register_bpf_struct_ops);
9577#endif
9578
9579bool btf_param_match_suffix(const struct btf *btf,
9580			    const struct btf_param *arg,
9581			    const char *suffix)
9582{
9583	int suffix_len = strlen(suffix), len;
9584	const char *param_name;
9585
9586	/* In the future, this can be ported to use BTF tagging */
9587	param_name = btf_name_by_offset(btf, arg->name_off);
9588	if (str_is_empty(param_name))
9589		return false;
9590	len = strlen(param_name);
9591	if (len <= suffix_len)
9592		return false;
9593	param_name += len - suffix_len;
9594	return !strncmp(param_name, suffix, suffix_len);
9595}