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cgroup.c
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linux-6.19.14/kernel/bpf/cgroup.c
1// SPDX-License-Identifier: GPL-2.0-only 2/* 3 * Functions to manage eBPF programs attached to cgroups 4 * 5 * Copyright (c) 2016 Daniel Mack 6 */ 7 8#include <linux/kernel.h> 9#include <linux/atomic.h> 10#include <linux/cgroup.h> 11#include <linux/filter.h> 12#include <linux/slab.h> 13#include <linux/sysctl.h> 14#include <linux/string.h> 15#include <linux/bpf.h> 16#include <linux/bpf-cgroup.h> 17#include <linux/bpf_lsm.h> 18#include <linux/bpf_verifier.h> 19#include <net/sock.h> 20#include <net/bpf_sk_storage.h> 21 22#include "../cgroup/cgroup-internal.h" 23 24DEFINE_STATIC_KEY_ARRAY_FALSE(cgroup_bpf_enabled_key, MAX_CGROUP_BPF_ATTACH_TYPE); 25EXPORT_SYMBOL(cgroup_bpf_enabled_key); 26 27/* 28 * cgroup bpf destruction makes heavy use of work items and there can be a lot 29 * of concurrent destructions. Use a separate workqueue so that cgroup bpf 30 * destruction work items don't end up filling up max_active of system_percpu_wq 31 * which may lead to deadlock. 32 */ 33static struct workqueue_struct *cgroup_bpf_destroy_wq; 34 35static int __init cgroup_bpf_wq_init(void) 36{ 37 cgroup_bpf_destroy_wq = alloc_workqueue("cgroup_bpf_destroy", 38 WQ_PERCPU, 1); 39 if (!cgroup_bpf_destroy_wq) 40 panic("Failed to alloc workqueue for cgroup bpf destroy.\n"); 41 return 0; 42} 43core_initcall(cgroup_bpf_wq_init); 44 45static int cgroup_bpf_lifetime_notify(struct notifier_block *nb, 46 unsigned long action, void *data); 47 48static struct notifier_block cgroup_bpf_lifetime_nb = { 49 .notifier_call = cgroup_bpf_lifetime_notify, 50}; 51 52void __init cgroup_bpf_lifetime_notifier_init(void) 53{ 54 BUG_ON(blocking_notifier_chain_register(&cgroup_lifetime_notifier, 55 &cgroup_bpf_lifetime_nb)); 56} 57 58/* __always_inline is necessary to prevent indirect call through run_prog 59 * function pointer. 60 */ 61static __always_inline int 62bpf_prog_run_array_cg(const struct cgroup_bpf *cgrp, 63 enum cgroup_bpf_attach_type atype, 64 const void *ctx, bpf_prog_run_fn run_prog, 65 int retval, u32 *ret_flags) 66{ 67 const struct bpf_prog_array_item *item; 68 const struct bpf_prog *prog; 69 const struct bpf_prog_array *array; 70 struct bpf_run_ctx *old_run_ctx; 71 struct bpf_cg_run_ctx run_ctx; 72 u32 func_ret; 73 74 run_ctx.retval = retval; 75 rcu_read_lock_dont_migrate(); 76 array = rcu_dereference(cgrp->effective[atype]); 77 item = &array->items[0]; 78 old_run_ctx = bpf_set_run_ctx(&run_ctx.run_ctx); 79 while ((prog = READ_ONCE(item->prog))) { 80 run_ctx.prog_item = item; 81 func_ret = run_prog(prog, ctx); 82 if (ret_flags) { 83 *(ret_flags) |= (func_ret >> 1); 84 func_ret &= 1; 85 } 86 if (!func_ret && !IS_ERR_VALUE((long)run_ctx.retval)) 87 run_ctx.retval = -EPERM; 88 item++; 89 } 90 bpf_reset_run_ctx(old_run_ctx); 91 rcu_read_unlock_migrate(); 92 return run_ctx.retval; 93} 94 95unsigned int __cgroup_bpf_run_lsm_sock(const void *ctx, 96 const struct bpf_insn *insn) 97{ 98 const struct bpf_prog *shim_prog; 99 struct sock *sk; 100 struct cgroup *cgrp; 101 int ret = 0; 102 u64 *args; 103 104 args = (u64 *)ctx; 105 sk = (void *)(unsigned long)args[0]; 106 /*shim_prog = container_of(insn, struct bpf_prog, insnsi);*/ 107 shim_prog = (const struct bpf_prog *)((void *)insn - offsetof(struct bpf_prog, insnsi)); 108 109 cgrp = sock_cgroup_ptr(&sk->sk_cgrp_data); 110 if (likely(cgrp)) 111 ret = bpf_prog_run_array_cg(&cgrp->bpf, 112 shim_prog->aux->cgroup_atype, 113 ctx, bpf_prog_run, 0, NULL); 114 return ret; 115} 116 117unsigned int __cgroup_bpf_run_lsm_socket(const void *ctx, 118 const struct bpf_insn *insn) 119{ 120 const struct bpf_prog *shim_prog; 121 struct socket *sock; 122 struct cgroup *cgrp; 123 int ret = 0; 124 u64 *args; 125 126 args = (u64 *)ctx; 127 sock = (void *)(unsigned long)args[0]; 128 /*shim_prog = container_of(insn, struct bpf_prog, insnsi);*/ 129 shim_prog = (const struct bpf_prog *)((void *)insn - offsetof(struct bpf_prog, insnsi)); 130 131 cgrp = sock_cgroup_ptr(&sock->sk->sk_cgrp_data); 132 if (likely(cgrp)) 133 ret = bpf_prog_run_array_cg(&cgrp->bpf, 134 shim_prog->aux->cgroup_atype, 135 ctx, bpf_prog_run, 0, NULL); 136 return ret; 137} 138 139unsigned int __cgroup_bpf_run_lsm_current(const void *ctx, 140 const struct bpf_insn *insn) 141{ 142 const struct bpf_prog *shim_prog; 143 struct cgroup *cgrp; 144 int ret = 0; 145 146 /*shim_prog = container_of(insn, struct bpf_prog, insnsi);*/ 147 shim_prog = (const struct bpf_prog *)((void *)insn - offsetof(struct bpf_prog, insnsi)); 148 149 /* We rely on trampoline's __bpf_prog_enter_lsm_cgroup to grab RCU read lock. */ 150 cgrp = task_dfl_cgroup(current); 151 if (likely(cgrp)) 152 ret = bpf_prog_run_array_cg(&cgrp->bpf, 153 shim_prog->aux->cgroup_atype, 154 ctx, bpf_prog_run, 0, NULL); 155 return ret; 156} 157 158#ifdef CONFIG_BPF_LSM 159struct cgroup_lsm_atype { 160 u32 attach_btf_id; 161 int refcnt; 162}; 163 164static struct cgroup_lsm_atype cgroup_lsm_atype[CGROUP_LSM_NUM]; 165 166static enum cgroup_bpf_attach_type 167bpf_cgroup_atype_find(enum bpf_attach_type attach_type, u32 attach_btf_id) 168{ 169 int i; 170 171 lockdep_assert_held(&cgroup_mutex); 172 173 if (attach_type != BPF_LSM_CGROUP) 174 return to_cgroup_bpf_attach_type(attach_type); 175 176 for (i = 0; i < ARRAY_SIZE(cgroup_lsm_atype); i++) 177 if (cgroup_lsm_atype[i].attach_btf_id == attach_btf_id) 178 return CGROUP_LSM_START + i; 179 180 for (i = 0; i < ARRAY_SIZE(cgroup_lsm_atype); i++) 181 if (cgroup_lsm_atype[i].attach_btf_id == 0) 182 return CGROUP_LSM_START + i; 183 184 return -E2BIG; 185 186} 187 188void bpf_cgroup_atype_get(u32 attach_btf_id, int cgroup_atype) 189{ 190 int i = cgroup_atype - CGROUP_LSM_START; 191 192 lockdep_assert_held(&cgroup_mutex); 193 194 WARN_ON_ONCE(cgroup_lsm_atype[i].attach_btf_id && 195 cgroup_lsm_atype[i].attach_btf_id != attach_btf_id); 196 197 cgroup_lsm_atype[i].attach_btf_id = attach_btf_id; 198 cgroup_lsm_atype[i].refcnt++; 199} 200 201void bpf_cgroup_atype_put(int cgroup_atype) 202{ 203 int i = cgroup_atype - CGROUP_LSM_START; 204 205 cgroup_lock(); 206 if (--cgroup_lsm_atype[i].refcnt <= 0) 207 cgroup_lsm_atype[i].attach_btf_id = 0; 208 WARN_ON_ONCE(cgroup_lsm_atype[i].refcnt < 0); 209 cgroup_unlock(); 210} 211#else 212static enum cgroup_bpf_attach_type 213bpf_cgroup_atype_find(enum bpf_attach_type attach_type, u32 attach_btf_id) 214{ 215 if (attach_type != BPF_LSM_CGROUP) 216 return to_cgroup_bpf_attach_type(attach_type); 217 return -EOPNOTSUPP; 218} 219#endif /* CONFIG_BPF_LSM */ 220 221static void cgroup_bpf_offline(struct cgroup *cgrp) 222{ 223 cgroup_get(cgrp); 224 percpu_ref_kill(&cgrp->bpf.refcnt); 225} 226 227static void bpf_cgroup_storages_free(struct bpf_cgroup_storage *storages[]) 228{ 229 enum bpf_cgroup_storage_type stype; 230 231 for_each_cgroup_storage_type(stype) 232 bpf_cgroup_storage_free(storages[stype]); 233} 234 235static int bpf_cgroup_storages_alloc(struct bpf_cgroup_storage *storages[], 236 struct bpf_cgroup_storage *new_storages[], 237 enum bpf_attach_type type, 238 struct bpf_prog *prog, 239 struct cgroup *cgrp) 240{ 241 enum bpf_cgroup_storage_type stype; 242 struct bpf_cgroup_storage_key key; 243 struct bpf_map *map; 244 245 key.cgroup_inode_id = cgroup_id(cgrp); 246 key.attach_type = type; 247 248 for_each_cgroup_storage_type(stype) { 249 map = prog->aux->cgroup_storage[stype]; 250 if (!map) 251 continue; 252 253 storages[stype] = cgroup_storage_lookup((void *)map, &key, false); 254 if (storages[stype]) 255 continue; 256 257 storages[stype] = bpf_cgroup_storage_alloc(prog, stype); 258 if (IS_ERR(storages[stype])) { 259 bpf_cgroup_storages_free(new_storages); 260 return -ENOMEM; 261 } 262 263 new_storages[stype] = storages[stype]; 264 } 265 266 return 0; 267} 268 269static void bpf_cgroup_storages_assign(struct bpf_cgroup_storage *dst[], 270 struct bpf_cgroup_storage *src[]) 271{ 272 enum bpf_cgroup_storage_type stype; 273 274 for_each_cgroup_storage_type(stype) 275 dst[stype] = src[stype]; 276} 277 278static void bpf_cgroup_storages_link(struct bpf_cgroup_storage *storages[], 279 struct cgroup *cgrp, 280 enum bpf_attach_type attach_type) 281{ 282 enum bpf_cgroup_storage_type stype; 283 284 for_each_cgroup_storage_type(stype) 285 bpf_cgroup_storage_link(storages[stype], cgrp, attach_type); 286} 287 288/* Called when bpf_cgroup_link is auto-detached from dying cgroup. 289 * It drops cgroup and bpf_prog refcounts, and marks bpf_link as defunct. It 290 * doesn't free link memory, which will eventually be done by bpf_link's 291 * release() callback, when its last FD is closed. 292 */ 293static void bpf_cgroup_link_auto_detach(struct bpf_cgroup_link *link) 294{ 295 cgroup_put(link->cgroup); 296 link->cgroup = NULL; 297} 298 299/** 300 * cgroup_bpf_release() - put references of all bpf programs and 301 * release all cgroup bpf data 302 * @work: work structure embedded into the cgroup to modify 303 */ 304static void cgroup_bpf_release(struct work_struct *work) 305{ 306 struct cgroup *p, *cgrp = container_of(work, struct cgroup, 307 bpf.release_work); 308 struct bpf_prog_array *old_array; 309 struct list_head *storages = &cgrp->bpf.storages; 310 struct bpf_cgroup_storage *storage, *stmp; 311 312 unsigned int atype; 313 314 cgroup_lock(); 315 316 for (atype = 0; atype < ARRAY_SIZE(cgrp->bpf.progs); atype++) { 317 struct hlist_head *progs = &cgrp->bpf.progs[atype]; 318 struct bpf_prog_list *pl; 319 struct hlist_node *pltmp; 320 321 hlist_for_each_entry_safe(pl, pltmp, progs, node) { 322 hlist_del(&pl->node); 323 if (pl->prog) { 324 if (pl->prog->expected_attach_type == BPF_LSM_CGROUP) 325 bpf_trampoline_unlink_cgroup_shim(pl->prog); 326 bpf_prog_put(pl->prog); 327 } 328 if (pl->link) { 329 if (pl->link->link.prog->expected_attach_type == BPF_LSM_CGROUP) 330 bpf_trampoline_unlink_cgroup_shim(pl->link->link.prog); 331 bpf_cgroup_link_auto_detach(pl->link); 332 } 333 kfree(pl); 334 static_branch_dec(&cgroup_bpf_enabled_key[atype]); 335 } 336 old_array = rcu_dereference_protected( 337 cgrp->bpf.effective[atype], 338 lockdep_is_held(&cgroup_mutex)); 339 bpf_prog_array_free(old_array); 340 } 341 342 list_for_each_entry_safe(storage, stmp, storages, list_cg) { 343 bpf_cgroup_storage_unlink(storage); 344 bpf_cgroup_storage_free(storage); 345 } 346 347 cgroup_unlock(); 348 349 for (p = cgroup_parent(cgrp); p; p = cgroup_parent(p)) 350 cgroup_bpf_put(p); 351 352 percpu_ref_exit(&cgrp->bpf.refcnt); 353 cgroup_put(cgrp); 354} 355 356/** 357 * cgroup_bpf_release_fn() - callback used to schedule releasing 358 * of bpf cgroup data 359 * @ref: percpu ref counter structure 360 */ 361static void cgroup_bpf_release_fn(struct percpu_ref *ref) 362{ 363 struct cgroup *cgrp = container_of(ref, struct cgroup, bpf.refcnt); 364 365 INIT_WORK(&cgrp->bpf.release_work, cgroup_bpf_release); 366 queue_work(cgroup_bpf_destroy_wq, &cgrp->bpf.release_work); 367} 368 369/* Get underlying bpf_prog of bpf_prog_list entry, regardless if it's through 370 * link or direct prog. 371 */ 372static struct bpf_prog *prog_list_prog(struct bpf_prog_list *pl) 373{ 374 if (pl->prog) 375 return pl->prog; 376 if (pl->link) 377 return pl->link->link.prog; 378 return NULL; 379} 380 381/* count number of elements in the list. 382 * it's slow but the list cannot be long 383 */ 384static u32 prog_list_length(struct hlist_head *head, int *preorder_cnt) 385{ 386 struct bpf_prog_list *pl; 387 u32 cnt = 0; 388 389 hlist_for_each_entry(pl, head, node) { 390 if (!prog_list_prog(pl)) 391 continue; 392 if (preorder_cnt && (pl->flags & BPF_F_PREORDER)) 393 (*preorder_cnt)++; 394 cnt++; 395 } 396 return cnt; 397} 398 399/* if parent has non-overridable prog attached, 400 * disallow attaching new programs to the descendent cgroup. 401 * if parent has overridable or multi-prog, allow attaching 402 */ 403static bool hierarchy_allows_attach(struct cgroup *cgrp, 404 enum cgroup_bpf_attach_type atype) 405{ 406 struct cgroup *p; 407 408 p = cgroup_parent(cgrp); 409 if (!p) 410 return true; 411 do { 412 u32 flags = p->bpf.flags[atype]; 413 u32 cnt; 414 415 if (flags & BPF_F_ALLOW_MULTI) 416 return true; 417 cnt = prog_list_length(&p->bpf.progs[atype], NULL); 418 WARN_ON_ONCE(cnt > 1); 419 if (cnt == 1) 420 return !!(flags & BPF_F_ALLOW_OVERRIDE); 421 p = cgroup_parent(p); 422 } while (p); 423 return true; 424} 425 426/* compute a chain of effective programs for a given cgroup: 427 * start from the list of programs in this cgroup and add 428 * all parent programs. 429 * Note that parent's F_ALLOW_OVERRIDE-type program is yielding 430 * to programs in this cgroup 431 */ 432static int compute_effective_progs(struct cgroup *cgrp, 433 enum cgroup_bpf_attach_type atype, 434 struct bpf_prog_array **array) 435{ 436 struct bpf_prog_array_item *item; 437 struct bpf_prog_array *progs; 438 struct bpf_prog_list *pl; 439 struct cgroup *p = cgrp; 440 int i, j, cnt = 0, preorder_cnt = 0, fstart, bstart, init_bstart; 441 442 /* count number of effective programs by walking parents */ 443 do { 444 if (cnt == 0 || (p->bpf.flags[atype] & BPF_F_ALLOW_MULTI)) 445 cnt += prog_list_length(&p->bpf.progs[atype], &preorder_cnt); 446 p = cgroup_parent(p); 447 } while (p); 448 449 progs = bpf_prog_array_alloc(cnt, GFP_KERNEL); 450 if (!progs) 451 return -ENOMEM; 452 453 /* populate the array with effective progs */ 454 cnt = 0; 455 p = cgrp; 456 fstart = preorder_cnt; 457 bstart = preorder_cnt - 1; 458 do { 459 if (cnt > 0 && !(p->bpf.flags[atype] & BPF_F_ALLOW_MULTI)) 460 continue; 461 462 init_bstart = bstart; 463 hlist_for_each_entry(pl, &p->bpf.progs[atype], node) { 464 if (!prog_list_prog(pl)) 465 continue; 466 467 if (pl->flags & BPF_F_PREORDER) { 468 item = &progs->items[bstart]; 469 bstart--; 470 } else { 471 item = &progs->items[fstart]; 472 fstart++; 473 } 474 item->prog = prog_list_prog(pl); 475 bpf_cgroup_storages_assign(item->cgroup_storage, 476 pl->storage); 477 cnt++; 478 } 479 480 /* reverse pre-ordering progs at this cgroup level */ 481 for (i = bstart + 1, j = init_bstart; i < j; i++, j--) 482 swap(progs->items[i], progs->items[j]); 483 484 } while ((p = cgroup_parent(p))); 485 486 *array = progs; 487 return 0; 488} 489 490static void activate_effective_progs(struct cgroup *cgrp, 491 enum cgroup_bpf_attach_type atype, 492 struct bpf_prog_array *old_array) 493{ 494 old_array = rcu_replace_pointer(cgrp->bpf.effective[atype], old_array, 495 lockdep_is_held(&cgroup_mutex)); 496 /* free prog array after grace period, since __cgroup_bpf_run_*() 497 * might be still walking the array 498 */ 499 bpf_prog_array_free(old_array); 500} 501 502/** 503 * cgroup_bpf_inherit() - inherit effective programs from parent 504 * @cgrp: the cgroup to modify 505 */ 506static int cgroup_bpf_inherit(struct cgroup *cgrp) 507{ 508/* has to use marco instead of const int, since compiler thinks 509 * that array below is variable length 510 */ 511#define NR ARRAY_SIZE(cgrp->bpf.effective) 512 struct bpf_prog_array *arrays[NR] = {}; 513 struct cgroup *p; 514 int ret, i; 515 516 ret = percpu_ref_init(&cgrp->bpf.refcnt, cgroup_bpf_release_fn, 0, 517 GFP_KERNEL); 518 if (ret) 519 return ret; 520 521 for (p = cgroup_parent(cgrp); p; p = cgroup_parent(p)) 522 cgroup_bpf_get(p); 523 524 for (i = 0; i < NR; i++) 525 INIT_HLIST_HEAD(&cgrp->bpf.progs[i]); 526 527 INIT_LIST_HEAD(&cgrp->bpf.storages); 528 529 for (i = 0; i < NR; i++) 530 if (compute_effective_progs(cgrp, i, &arrays[i])) 531 goto cleanup; 532 533 for (i = 0; i < NR; i++) 534 activate_effective_progs(cgrp, i, arrays[i]); 535 536 return 0; 537cleanup: 538 for (i = 0; i < NR; i++) 539 bpf_prog_array_free(arrays[i]); 540 541 for (p = cgroup_parent(cgrp); p; p = cgroup_parent(p)) 542 cgroup_bpf_put(p); 543 544 percpu_ref_exit(&cgrp->bpf.refcnt); 545 546 return -ENOMEM; 547} 548 549static int cgroup_bpf_lifetime_notify(struct notifier_block *nb, 550 unsigned long action, void *data) 551{ 552 struct cgroup *cgrp = data; 553 int ret = 0; 554 555 if (cgrp->root != &cgrp_dfl_root) 556 return NOTIFY_OK; 557 558 switch (action) { 559 case CGROUP_LIFETIME_ONLINE: 560 ret = cgroup_bpf_inherit(cgrp); 561 break; 562 case CGROUP_LIFETIME_OFFLINE: 563 cgroup_bpf_offline(cgrp); 564 break; 565 } 566 567 return notifier_from_errno(ret); 568} 569 570static int update_effective_progs(struct cgroup *cgrp, 571 enum cgroup_bpf_attach_type atype) 572{ 573 struct cgroup_subsys_state *css; 574 int err; 575 576 /* allocate and recompute effective prog arrays */ 577 css_for_each_descendant_pre(css, &cgrp->self) { 578 struct cgroup *desc = container_of(css, struct cgroup, self); 579 580 if (percpu_ref_is_zero(&desc->bpf.refcnt)) 581 continue; 582 583 err = compute_effective_progs(desc, atype, &desc->bpf.inactive); 584 if (err) 585 goto cleanup; 586 } 587 588 /* all allocations were successful. Activate all prog arrays */ 589 css_for_each_descendant_pre(css, &cgrp->self) { 590 struct cgroup *desc = container_of(css, struct cgroup, self); 591 592 if (percpu_ref_is_zero(&desc->bpf.refcnt)) { 593 if (unlikely(desc->bpf.inactive)) { 594 bpf_prog_array_free(desc->bpf.inactive); 595 desc->bpf.inactive = NULL; 596 } 597 continue; 598 } 599 600 activate_effective_progs(desc, atype, desc->bpf.inactive); 601 desc->bpf.inactive = NULL; 602 } 603 604 return 0; 605 606cleanup: 607 /* oom while computing effective. Free all computed effective arrays 608 * since they were not activated 609 */ 610 css_for_each_descendant_pre(css, &cgrp->self) { 611 struct cgroup *desc = container_of(css, struct cgroup, self); 612 613 bpf_prog_array_free(desc->bpf.inactive); 614 desc->bpf.inactive = NULL; 615 } 616 617 return err; 618} 619 620#define BPF_CGROUP_MAX_PROGS 64 621 622static struct bpf_prog_list *find_attach_entry(struct hlist_head *progs, 623 struct bpf_prog *prog, 624 struct bpf_cgroup_link *link, 625 struct bpf_prog *replace_prog, 626 bool allow_multi) 627{ 628 struct bpf_prog_list *pl; 629 630 /* single-attach case */ 631 if (!allow_multi) { 632 if (hlist_empty(progs)) 633 return NULL; 634 return hlist_entry(progs->first, typeof(*pl), node); 635 } 636 637 hlist_for_each_entry(pl, progs, node) { 638 if (prog && pl->prog == prog && prog != replace_prog) 639 /* disallow attaching the same prog twice */ 640 return ERR_PTR(-EINVAL); 641 if (link && pl->link == link) 642 /* disallow attaching the same link twice */ 643 return ERR_PTR(-EINVAL); 644 } 645 646 /* direct prog multi-attach w/ replacement case */ 647 if (replace_prog) { 648 hlist_for_each_entry(pl, progs, node) { 649 if (pl->prog == replace_prog) 650 /* a match found */ 651 return pl; 652 } 653 /* prog to replace not found for cgroup */ 654 return ERR_PTR(-ENOENT); 655 } 656 657 return NULL; 658} 659 660static struct bpf_link *bpf_get_anchor_link(u32 flags, u32 id_or_fd) 661{ 662 struct bpf_link *link = ERR_PTR(-EINVAL); 663 664 if (flags & BPF_F_ID) 665 link = bpf_link_by_id(id_or_fd); 666 else if (id_or_fd) 667 link = bpf_link_get_from_fd(id_or_fd); 668 return link; 669} 670 671static struct bpf_prog *bpf_get_anchor_prog(u32 flags, u32 id_or_fd) 672{ 673 struct bpf_prog *prog = ERR_PTR(-EINVAL); 674 675 if (flags & BPF_F_ID) 676 prog = bpf_prog_by_id(id_or_fd); 677 else if (id_or_fd) 678 prog = bpf_prog_get(id_or_fd); 679 return prog; 680} 681 682static struct bpf_prog_list *get_prog_list(struct hlist_head *progs, struct bpf_prog *prog, 683 struct bpf_cgroup_link *link, u32 flags, u32 id_or_fd) 684{ 685 bool is_link = flags & BPF_F_LINK, is_id = flags & BPF_F_ID; 686 struct bpf_prog_list *pltmp, *pl = ERR_PTR(-EINVAL); 687 bool preorder = flags & BPF_F_PREORDER; 688 struct bpf_link *anchor_link = NULL; 689 struct bpf_prog *anchor_prog = NULL; 690 bool is_before, is_after; 691 692 is_before = flags & BPF_F_BEFORE; 693 is_after = flags & BPF_F_AFTER; 694 if (is_link || is_id || id_or_fd) { 695 /* flags must have either BPF_F_BEFORE or BPF_F_AFTER */ 696 if (is_before == is_after) 697 return ERR_PTR(-EINVAL); 698 if ((is_link && !link) || (!is_link && !prog)) 699 return ERR_PTR(-EINVAL); 700 } else if (!hlist_empty(progs)) { 701 /* flags cannot have both BPF_F_BEFORE and BPF_F_AFTER */ 702 if (is_before && is_after) 703 return ERR_PTR(-EINVAL); 704 } 705 706 if (is_link) { 707 anchor_link = bpf_get_anchor_link(flags, id_or_fd); 708 if (IS_ERR(anchor_link)) 709 return ERR_CAST(anchor_link); 710 } else if (is_id || id_or_fd) { 711 anchor_prog = bpf_get_anchor_prog(flags, id_or_fd); 712 if (IS_ERR(anchor_prog)) 713 return ERR_CAST(anchor_prog); 714 } 715 716 if (!anchor_prog && !anchor_link) { 717 /* if there is no anchor_prog/anchor_link, then BPF_F_PREORDER 718 * doesn't matter since either prepend or append to a combined 719 * list of progs will end up with correct result. 720 */ 721 hlist_for_each_entry(pltmp, progs, node) { 722 if (is_before) 723 return pltmp; 724 if (pltmp->node.next) 725 continue; 726 return pltmp; 727 } 728 return NULL; 729 } 730 731 hlist_for_each_entry(pltmp, progs, node) { 732 if ((anchor_prog && anchor_prog == pltmp->prog) || 733 (anchor_link && anchor_link == &pltmp->link->link)) { 734 if (!!(pltmp->flags & BPF_F_PREORDER) != preorder) 735 goto out; 736 pl = pltmp; 737 goto out; 738 } 739 } 740 741 pl = ERR_PTR(-ENOENT); 742out: 743 if (anchor_link) 744 bpf_link_put(anchor_link); 745 else 746 bpf_prog_put(anchor_prog); 747 return pl; 748} 749 750static int insert_pl_to_hlist(struct bpf_prog_list *pl, struct hlist_head *progs, 751 struct bpf_prog *prog, struct bpf_cgroup_link *link, 752 u32 flags, u32 id_or_fd) 753{ 754 struct bpf_prog_list *pltmp; 755 756 pltmp = get_prog_list(progs, prog, link, flags, id_or_fd); 757 if (IS_ERR(pltmp)) 758 return PTR_ERR(pltmp); 759 760 if (!pltmp) 761 hlist_add_head(&pl->node, progs); 762 else if (flags & BPF_F_BEFORE) 763 hlist_add_before(&pl->node, &pltmp->node); 764 else 765 hlist_add_behind(&pl->node, &pltmp->node); 766 767 return 0; 768} 769 770/** 771 * __cgroup_bpf_attach() - Attach the program or the link to a cgroup, and 772 * propagate the change to descendants 773 * @cgrp: The cgroup which descendants to traverse 774 * @prog: A program to attach 775 * @link: A link to attach 776 * @replace_prog: Previously attached program to replace if BPF_F_REPLACE is set 777 * @type: Type of attach operation 778 * @flags: Option flags 779 * @id_or_fd: Relative prog id or fd 780 * @revision: bpf_prog_list revision 781 * 782 * Exactly one of @prog or @link can be non-null. 783 * Must be called with cgroup_mutex held. 784 */ 785static int __cgroup_bpf_attach(struct cgroup *cgrp, 786 struct bpf_prog *prog, struct bpf_prog *replace_prog, 787 struct bpf_cgroup_link *link, 788 enum bpf_attach_type type, u32 flags, u32 id_or_fd, 789 u64 revision) 790{ 791 u32 saved_flags = (flags & (BPF_F_ALLOW_OVERRIDE | BPF_F_ALLOW_MULTI)); 792 struct bpf_prog *old_prog = NULL; 793 struct bpf_cgroup_storage *storage[MAX_BPF_CGROUP_STORAGE_TYPE] = {}; 794 struct bpf_cgroup_storage *new_storage[MAX_BPF_CGROUP_STORAGE_TYPE] = {}; 795 struct bpf_prog *new_prog = prog ? : link->link.prog; 796 enum cgroup_bpf_attach_type atype; 797 struct bpf_prog_list *pl; 798 struct hlist_head *progs; 799 int err; 800 801 if (((flags & BPF_F_ALLOW_OVERRIDE) && (flags & BPF_F_ALLOW_MULTI)) || 802 ((flags & BPF_F_REPLACE) && !(flags & BPF_F_ALLOW_MULTI))) 803 /* invalid combination */ 804 return -EINVAL; 805 if ((flags & BPF_F_REPLACE) && (flags & (BPF_F_BEFORE | BPF_F_AFTER))) 806 /* only either replace or insertion with before/after */ 807 return -EINVAL; 808 if (link && (prog || replace_prog)) 809 /* only either link or prog/replace_prog can be specified */ 810 return -EINVAL; 811 if (!!replace_prog != !!(flags & BPF_F_REPLACE)) 812 /* replace_prog implies BPF_F_REPLACE, and vice versa */ 813 return -EINVAL; 814 815 atype = bpf_cgroup_atype_find(type, new_prog->aux->attach_btf_id); 816 if (atype < 0) 817 return -EINVAL; 818 if (revision && revision != cgrp->bpf.revisions[atype]) 819 return -ESTALE; 820 821 progs = &cgrp->bpf.progs[atype]; 822 823 if (!hierarchy_allows_attach(cgrp, atype)) 824 return -EPERM; 825 826 if (!hlist_empty(progs) && cgrp->bpf.flags[atype] != saved_flags) 827 /* Disallow attaching non-overridable on top 828 * of existing overridable in this cgroup. 829 * Disallow attaching multi-prog if overridable or none 830 */ 831 return -EPERM; 832 833 if (prog_list_length(progs, NULL) >= BPF_CGROUP_MAX_PROGS) 834 return -E2BIG; 835 836 pl = find_attach_entry(progs, prog, link, replace_prog, 837 flags & BPF_F_ALLOW_MULTI); 838 if (IS_ERR(pl)) 839 return PTR_ERR(pl); 840 841 if (bpf_cgroup_storages_alloc(storage, new_storage, type, 842 prog ? : link->link.prog, cgrp)) 843 return -ENOMEM; 844 845 if (pl) { 846 old_prog = pl->prog; 847 } else { 848 pl = kmalloc(sizeof(*pl), GFP_KERNEL); 849 if (!pl) { 850 bpf_cgroup_storages_free(new_storage); 851 return -ENOMEM; 852 } 853 854 err = insert_pl_to_hlist(pl, progs, prog, link, flags, id_or_fd); 855 if (err) { 856 kfree(pl); 857 bpf_cgroup_storages_free(new_storage); 858 return err; 859 } 860 } 861 862 pl->prog = prog; 863 pl->link = link; 864 pl->flags = flags; 865 bpf_cgroup_storages_assign(pl->storage, storage); 866 cgrp->bpf.flags[atype] = saved_flags; 867 868 if (type == BPF_LSM_CGROUP) { 869 err = bpf_trampoline_link_cgroup_shim(new_prog, atype, type); 870 if (err) 871 goto cleanup; 872 } 873 874 err = update_effective_progs(cgrp, atype); 875 if (err) 876 goto cleanup_trampoline; 877 878 cgrp->bpf.revisions[atype] += 1; 879 if (old_prog) { 880 if (type == BPF_LSM_CGROUP) 881 bpf_trampoline_unlink_cgroup_shim(old_prog); 882 bpf_prog_put(old_prog); 883 } else { 884 static_branch_inc(&cgroup_bpf_enabled_key[atype]); 885 } 886 bpf_cgroup_storages_link(new_storage, cgrp, type); 887 return 0; 888 889cleanup_trampoline: 890 if (type == BPF_LSM_CGROUP) 891 bpf_trampoline_unlink_cgroup_shim(new_prog); 892 893cleanup: 894 if (old_prog) { 895 pl->prog = old_prog; 896 pl->link = NULL; 897 } 898 bpf_cgroup_storages_free(new_storage); 899 if (!old_prog) { 900 hlist_del(&pl->node); 901 kfree(pl); 902 } 903 return err; 904} 905 906static int cgroup_bpf_attach(struct cgroup *cgrp, 907 struct bpf_prog *prog, struct bpf_prog *replace_prog, 908 struct bpf_cgroup_link *link, 909 enum bpf_attach_type type, 910 u32 flags, u32 id_or_fd, u64 revision) 911{ 912 int ret; 913 914 cgroup_lock(); 915 ret = __cgroup_bpf_attach(cgrp, prog, replace_prog, link, type, flags, 916 id_or_fd, revision); 917 cgroup_unlock(); 918 return ret; 919} 920 921/* Swap updated BPF program for given link in effective program arrays across 922 * all descendant cgroups. This function is guaranteed to succeed. 923 */ 924static void replace_effective_prog(struct cgroup *cgrp, 925 enum cgroup_bpf_attach_type atype, 926 struct bpf_cgroup_link *link) 927{ 928 struct bpf_prog_array_item *item; 929 struct cgroup_subsys_state *css; 930 struct bpf_prog_array *progs; 931 struct bpf_prog_list *pl; 932 struct hlist_head *head; 933 struct cgroup *cg; 934 int pos; 935 936 css_for_each_descendant_pre(css, &cgrp->self) { 937 struct cgroup *desc = container_of(css, struct cgroup, self); 938 939 if (percpu_ref_is_zero(&desc->bpf.refcnt)) 940 continue; 941 942 /* find position of link in effective progs array */ 943 for (pos = 0, cg = desc; cg; cg = cgroup_parent(cg)) { 944 if (pos && !(cg->bpf.flags[atype] & BPF_F_ALLOW_MULTI)) 945 continue; 946 947 head = &cg->bpf.progs[atype]; 948 hlist_for_each_entry(pl, head, node) { 949 if (!prog_list_prog(pl)) 950 continue; 951 if (pl->link == link) 952 goto found; 953 pos++; 954 } 955 } 956found: 957 BUG_ON(!cg); 958 progs = rcu_dereference_protected( 959 desc->bpf.effective[atype], 960 lockdep_is_held(&cgroup_mutex)); 961 item = &progs->items[pos]; 962 WRITE_ONCE(item->prog, link->link.prog); 963 } 964} 965 966/** 967 * __cgroup_bpf_replace() - Replace link's program and propagate the change 968 * to descendants 969 * @cgrp: The cgroup which descendants to traverse 970 * @link: A link for which to replace BPF program 971 * @new_prog: &struct bpf_prog for the target BPF program with its refcnt 972 * incremented 973 * 974 * Must be called with cgroup_mutex held. 975 */ 976static int __cgroup_bpf_replace(struct cgroup *cgrp, 977 struct bpf_cgroup_link *link, 978 struct bpf_prog *new_prog) 979{ 980 enum cgroup_bpf_attach_type atype; 981 struct bpf_prog *old_prog; 982 struct bpf_prog_list *pl; 983 struct hlist_head *progs; 984 bool found = false; 985 986 atype = bpf_cgroup_atype_find(link->link.attach_type, new_prog->aux->attach_btf_id); 987 if (atype < 0) 988 return -EINVAL; 989 990 progs = &cgrp->bpf.progs[atype]; 991 992 if (link->link.prog->type != new_prog->type) 993 return -EINVAL; 994 995 hlist_for_each_entry(pl, progs, node) { 996 if (pl->link == link) { 997 found = true; 998 break; 999 } 1000 } 1001 if (!found) 1002 return -ENOENT; 1003 1004 cgrp->bpf.revisions[atype] += 1; 1005 old_prog = xchg(&link->link.prog, new_prog); 1006 replace_effective_prog(cgrp, atype, link); 1007 bpf_prog_put(old_prog); 1008 return 0; 1009} 1010 1011static int cgroup_bpf_replace(struct bpf_link *link, struct bpf_prog *new_prog, 1012 struct bpf_prog *old_prog) 1013{ 1014 struct bpf_cgroup_link *cg_link; 1015 int ret; 1016 1017 cg_link = container_of(link, struct bpf_cgroup_link, link); 1018 1019 cgroup_lock(); 1020 /* link might have been auto-released by dying cgroup, so fail */ 1021 if (!cg_link->cgroup) { 1022 ret = -ENOLINK; 1023 goto out_unlock; 1024 } 1025 if (old_prog && link->prog != old_prog) { 1026 ret = -EPERM; 1027 goto out_unlock; 1028 } 1029 ret = __cgroup_bpf_replace(cg_link->cgroup, cg_link, new_prog); 1030out_unlock: 1031 cgroup_unlock(); 1032 return ret; 1033} 1034 1035static struct bpf_prog_list *find_detach_entry(struct hlist_head *progs, 1036 struct bpf_prog *prog, 1037 struct bpf_cgroup_link *link, 1038 bool allow_multi) 1039{ 1040 struct bpf_prog_list *pl; 1041 1042 if (!allow_multi) { 1043 if (hlist_empty(progs)) 1044 /* report error when trying to detach and nothing is attached */ 1045 return ERR_PTR(-ENOENT); 1046 1047 /* to maintain backward compatibility NONE and OVERRIDE cgroups 1048 * allow detaching with invalid FD (prog==NULL) in legacy mode 1049 */ 1050 return hlist_entry(progs->first, typeof(*pl), node); 1051 } 1052 1053 if (!prog && !link) 1054 /* to detach MULTI prog the user has to specify valid FD 1055 * of the program or link to be detached 1056 */ 1057 return ERR_PTR(-EINVAL); 1058 1059 /* find the prog or link and detach it */ 1060 hlist_for_each_entry(pl, progs, node) { 1061 if (pl->prog == prog && pl->link == link) 1062 return pl; 1063 } 1064 return ERR_PTR(-ENOENT); 1065} 1066 1067/** 1068 * purge_effective_progs() - After compute_effective_progs fails to alloc new 1069 * cgrp->bpf.inactive table we can recover by 1070 * recomputing the array in place. 1071 * 1072 * @cgrp: The cgroup which descendants to travers 1073 * @prog: A program to detach or NULL 1074 * @link: A link to detach or NULL 1075 * @atype: Type of detach operation 1076 */ 1077static void purge_effective_progs(struct cgroup *cgrp, struct bpf_prog *prog, 1078 struct bpf_cgroup_link *link, 1079 enum cgroup_bpf_attach_type atype) 1080{ 1081 struct cgroup_subsys_state *css; 1082 struct bpf_prog_array *progs; 1083 struct bpf_prog_list *pl; 1084 struct hlist_head *head; 1085 struct cgroup *cg; 1086 int pos; 1087 1088 /* recompute effective prog array in place */ 1089 css_for_each_descendant_pre(css, &cgrp->self) { 1090 struct cgroup *desc = container_of(css, struct cgroup, self); 1091 1092 if (percpu_ref_is_zero(&desc->bpf.refcnt)) 1093 continue; 1094 1095 /* find position of link or prog in effective progs array */ 1096 for (pos = 0, cg = desc; cg; cg = cgroup_parent(cg)) { 1097 if (pos && !(cg->bpf.flags[atype] & BPF_F_ALLOW_MULTI)) 1098 continue; 1099 1100 head = &cg->bpf.progs[atype]; 1101 hlist_for_each_entry(pl, head, node) { 1102 if (!prog_list_prog(pl)) 1103 continue; 1104 if (pl->prog == prog && pl->link == link) 1105 goto found; 1106 pos++; 1107 } 1108 } 1109 1110 /* no link or prog match, skip the cgroup of this layer */ 1111 continue; 1112found: 1113 progs = rcu_dereference_protected( 1114 desc->bpf.effective[atype], 1115 lockdep_is_held(&cgroup_mutex)); 1116 1117 /* Remove the program from the array */ 1118 WARN_ONCE(bpf_prog_array_delete_safe_at(progs, pos), 1119 "Failed to purge a prog from array at index %d", pos); 1120 } 1121} 1122 1123/** 1124 * __cgroup_bpf_detach() - Detach the program or link from a cgroup, and 1125 * propagate the change to descendants 1126 * @cgrp: The cgroup which descendants to traverse 1127 * @prog: A program to detach or NULL 1128 * @link: A link to detach or NULL 1129 * @type: Type of detach operation 1130 * @revision: bpf_prog_list revision 1131 * 1132 * At most one of @prog or @link can be non-NULL. 1133 * Must be called with cgroup_mutex held. 1134 */ 1135static int __cgroup_bpf_detach(struct cgroup *cgrp, struct bpf_prog *prog, 1136 struct bpf_cgroup_link *link, enum bpf_attach_type type, 1137 u64 revision) 1138{ 1139 enum cgroup_bpf_attach_type atype; 1140 struct bpf_prog *old_prog; 1141 struct bpf_prog_list *pl; 1142 struct hlist_head *progs; 1143 u32 attach_btf_id = 0; 1144 u32 flags; 1145 1146 if (prog) 1147 attach_btf_id = prog->aux->attach_btf_id; 1148 if (link) 1149 attach_btf_id = link->link.prog->aux->attach_btf_id; 1150 1151 atype = bpf_cgroup_atype_find(type, attach_btf_id); 1152 if (atype < 0) 1153 return -EINVAL; 1154 1155 if (revision && revision != cgrp->bpf.revisions[atype]) 1156 return -ESTALE; 1157 1158 progs = &cgrp->bpf.progs[atype]; 1159 flags = cgrp->bpf.flags[atype]; 1160 1161 if (prog && link) 1162 /* only one of prog or link can be specified */ 1163 return -EINVAL; 1164 1165 pl = find_detach_entry(progs, prog, link, flags & BPF_F_ALLOW_MULTI); 1166 if (IS_ERR(pl)) 1167 return PTR_ERR(pl); 1168 1169 /* mark it deleted, so it's ignored while recomputing effective */ 1170 old_prog = pl->prog; 1171 pl->prog = NULL; 1172 pl->link = NULL; 1173 1174 if (update_effective_progs(cgrp, atype)) { 1175 /* if update effective array failed replace the prog with a dummy prog*/ 1176 pl->prog = old_prog; 1177 pl->link = link; 1178 purge_effective_progs(cgrp, old_prog, link, atype); 1179 } 1180 1181 /* now can actually delete it from this cgroup list */ 1182 hlist_del(&pl->node); 1183 cgrp->bpf.revisions[atype] += 1; 1184 1185 kfree(pl); 1186 if (hlist_empty(progs)) 1187 /* last program was detached, reset flags to zero */ 1188 cgrp->bpf.flags[atype] = 0; 1189 if (old_prog) { 1190 if (type == BPF_LSM_CGROUP) 1191 bpf_trampoline_unlink_cgroup_shim(old_prog); 1192 bpf_prog_put(old_prog); 1193 } 1194 static_branch_dec(&cgroup_bpf_enabled_key[atype]); 1195 return 0; 1196} 1197 1198static int cgroup_bpf_detach(struct cgroup *cgrp, struct bpf_prog *prog, 1199 enum bpf_attach_type type, u64 revision) 1200{ 1201 int ret; 1202 1203 cgroup_lock(); 1204 ret = __cgroup_bpf_detach(cgrp, prog, NULL, type, revision); 1205 cgroup_unlock(); 1206 return ret; 1207} 1208 1209/* Must be called with cgroup_mutex held to avoid races. */ 1210static int __cgroup_bpf_query(struct cgroup *cgrp, const union bpf_attr *attr, 1211 union bpf_attr __user *uattr) 1212{ 1213 __u32 __user *prog_attach_flags = u64_to_user_ptr(attr->query.prog_attach_flags); 1214 bool effective_query = attr->query.query_flags & BPF_F_QUERY_EFFECTIVE; 1215 __u32 __user *prog_ids = u64_to_user_ptr(attr->query.prog_ids); 1216 enum bpf_attach_type type = attr->query.attach_type; 1217 enum cgroup_bpf_attach_type from_atype, to_atype; 1218 enum cgroup_bpf_attach_type atype; 1219 struct bpf_prog_array *effective; 1220 int cnt, ret = 0, i; 1221 int total_cnt = 0; 1222 u64 revision = 0; 1223 u32 flags; 1224 1225 if (effective_query && prog_attach_flags) 1226 return -EINVAL; 1227 1228 if (type == BPF_LSM_CGROUP) { 1229 if (!effective_query && attr->query.prog_cnt && 1230 prog_ids && !prog_attach_flags) 1231 return -EINVAL; 1232 1233 from_atype = CGROUP_LSM_START; 1234 to_atype = CGROUP_LSM_END; 1235 flags = 0; 1236 } else { 1237 from_atype = to_cgroup_bpf_attach_type(type); 1238 if (from_atype < 0) 1239 return -EINVAL; 1240 to_atype = from_atype; 1241 flags = cgrp->bpf.flags[from_atype]; 1242 } 1243 1244 for (atype = from_atype; atype <= to_atype; atype++) { 1245 if (effective_query) { 1246 effective = rcu_dereference_protected(cgrp->bpf.effective[atype], 1247 lockdep_is_held(&cgroup_mutex)); 1248 total_cnt += bpf_prog_array_length(effective); 1249 } else { 1250 total_cnt += prog_list_length(&cgrp->bpf.progs[atype], NULL); 1251 } 1252 } 1253 1254 /* always output uattr->query.attach_flags as 0 during effective query */ 1255 flags = effective_query ? 0 : flags; 1256 if (copy_to_user(&uattr->query.attach_flags, &flags, sizeof(flags))) 1257 return -EFAULT; 1258 if (copy_to_user(&uattr->query.prog_cnt, &total_cnt, sizeof(total_cnt))) 1259 return -EFAULT; 1260 if (!effective_query && from_atype == to_atype) 1261 revision = cgrp->bpf.revisions[from_atype]; 1262 if (copy_to_user(&uattr->query.revision, &revision, sizeof(revision))) 1263 return -EFAULT; 1264 if (attr->query.prog_cnt == 0 || !prog_ids || !total_cnt) 1265 /* return early if user requested only program count + flags */ 1266 return 0; 1267 1268 if (attr->query.prog_cnt < total_cnt) { 1269 total_cnt = attr->query.prog_cnt; 1270 ret = -ENOSPC; 1271 } 1272 1273 for (atype = from_atype; atype <= to_atype && total_cnt; atype++) { 1274 if (effective_query) { 1275 effective = rcu_dereference_protected(cgrp->bpf.effective[atype], 1276 lockdep_is_held(&cgroup_mutex)); 1277 cnt = min_t(int, bpf_prog_array_length(effective), total_cnt); 1278 ret = bpf_prog_array_copy_to_user(effective, prog_ids, cnt); 1279 } else { 1280 struct hlist_head *progs; 1281 struct bpf_prog_list *pl; 1282 struct bpf_prog *prog; 1283 u32 id; 1284 1285 progs = &cgrp->bpf.progs[atype]; 1286 cnt = min_t(int, prog_list_length(progs, NULL), total_cnt); 1287 i = 0; 1288 hlist_for_each_entry(pl, progs, node) { 1289 prog = prog_list_prog(pl); 1290 id = prog->aux->id; 1291 if (copy_to_user(prog_ids + i, &id, sizeof(id))) 1292 return -EFAULT; 1293 if (++i == cnt) 1294 break; 1295 } 1296 1297 if (prog_attach_flags) { 1298 flags = cgrp->bpf.flags[atype]; 1299 1300 for (i = 0; i < cnt; i++) 1301 if (copy_to_user(prog_attach_flags + i, 1302 &flags, sizeof(flags))) 1303 return -EFAULT; 1304 prog_attach_flags += cnt; 1305 } 1306 } 1307 1308 prog_ids += cnt; 1309 total_cnt -= cnt; 1310 } 1311 return ret; 1312} 1313 1314static int cgroup_bpf_query(struct cgroup *cgrp, const union bpf_attr *attr, 1315 union bpf_attr __user *uattr) 1316{ 1317 int ret; 1318 1319 cgroup_lock(); 1320 ret = __cgroup_bpf_query(cgrp, attr, uattr); 1321 cgroup_unlock(); 1322 return ret; 1323} 1324 1325int cgroup_bpf_prog_attach(const union bpf_attr *attr, 1326 enum bpf_prog_type ptype, struct bpf_prog *prog) 1327{ 1328 struct bpf_prog *replace_prog = NULL; 1329 struct cgroup *cgrp; 1330 int ret; 1331 1332 cgrp = cgroup_get_from_fd(attr->target_fd); 1333 if (IS_ERR(cgrp)) 1334 return PTR_ERR(cgrp); 1335 1336 if ((attr->attach_flags & BPF_F_ALLOW_MULTI) && 1337 (attr->attach_flags & BPF_F_REPLACE)) { 1338 replace_prog = bpf_prog_get_type(attr->replace_bpf_fd, ptype); 1339 if (IS_ERR(replace_prog)) { 1340 cgroup_put(cgrp); 1341 return PTR_ERR(replace_prog); 1342 } 1343 } 1344 1345 ret = cgroup_bpf_attach(cgrp, prog, replace_prog, NULL, 1346 attr->attach_type, attr->attach_flags, 1347 attr->relative_fd, attr->expected_revision); 1348 1349 if (replace_prog) 1350 bpf_prog_put(replace_prog); 1351 cgroup_put(cgrp); 1352 return ret; 1353} 1354 1355int cgroup_bpf_prog_detach(const union bpf_attr *attr, enum bpf_prog_type ptype) 1356{ 1357 struct bpf_prog *prog; 1358 struct cgroup *cgrp; 1359 int ret; 1360 1361 cgrp = cgroup_get_from_fd(attr->target_fd); 1362 if (IS_ERR(cgrp)) 1363 return PTR_ERR(cgrp); 1364 1365 prog = bpf_prog_get_type(attr->attach_bpf_fd, ptype); 1366 if (IS_ERR(prog)) 1367 prog = NULL; 1368 1369 ret = cgroup_bpf_detach(cgrp, prog, attr->attach_type, attr->expected_revision); 1370 if (prog) 1371 bpf_prog_put(prog); 1372 1373 cgroup_put(cgrp); 1374 return ret; 1375} 1376 1377static void bpf_cgroup_link_release(struct bpf_link *link) 1378{ 1379 struct bpf_cgroup_link *cg_link = 1380 container_of(link, struct bpf_cgroup_link, link); 1381 struct cgroup *cg; 1382 1383 /* link might have been auto-detached by dying cgroup already, 1384 * in that case our work is done here 1385 */ 1386 if (!cg_link->cgroup) 1387 return; 1388 1389 cgroup_lock(); 1390 1391 /* re-check cgroup under lock again */ 1392 if (!cg_link->cgroup) { 1393 cgroup_unlock(); 1394 return; 1395 } 1396 1397 WARN_ON(__cgroup_bpf_detach(cg_link->cgroup, NULL, cg_link, 1398 link->attach_type, 0)); 1399 if (link->attach_type == BPF_LSM_CGROUP) 1400 bpf_trampoline_unlink_cgroup_shim(cg_link->link.prog); 1401 1402 cg = cg_link->cgroup; 1403 cg_link->cgroup = NULL; 1404 1405 cgroup_unlock(); 1406 1407 cgroup_put(cg); 1408} 1409 1410static void bpf_cgroup_link_dealloc(struct bpf_link *link) 1411{ 1412 struct bpf_cgroup_link *cg_link = 1413 container_of(link, struct bpf_cgroup_link, link); 1414 1415 kfree(cg_link); 1416} 1417 1418static int bpf_cgroup_link_detach(struct bpf_link *link) 1419{ 1420 bpf_cgroup_link_release(link); 1421 1422 return 0; 1423} 1424 1425static void bpf_cgroup_link_show_fdinfo(const struct bpf_link *link, 1426 struct seq_file *seq) 1427{ 1428 struct bpf_cgroup_link *cg_link = 1429 container_of(link, struct bpf_cgroup_link, link); 1430 u64 cg_id = 0; 1431 1432 cgroup_lock(); 1433 if (cg_link->cgroup) 1434 cg_id = cgroup_id(cg_link->cgroup); 1435 cgroup_unlock(); 1436 1437 seq_printf(seq, 1438 "cgroup_id:\t%llu\n" 1439 "attach_type:\t%d\n", 1440 cg_id, 1441 link->attach_type); 1442} 1443 1444static int bpf_cgroup_link_fill_link_info(const struct bpf_link *link, 1445 struct bpf_link_info *info) 1446{ 1447 struct bpf_cgroup_link *cg_link = 1448 container_of(link, struct bpf_cgroup_link, link); 1449 u64 cg_id = 0; 1450 1451 cgroup_lock(); 1452 if (cg_link->cgroup) 1453 cg_id = cgroup_id(cg_link->cgroup); 1454 cgroup_unlock(); 1455 1456 info->cgroup.cgroup_id = cg_id; 1457 info->cgroup.attach_type = link->attach_type; 1458 return 0; 1459} 1460 1461static const struct bpf_link_ops bpf_cgroup_link_lops = { 1462 .release = bpf_cgroup_link_release, 1463 .dealloc = bpf_cgroup_link_dealloc, 1464 .detach = bpf_cgroup_link_detach, 1465 .update_prog = cgroup_bpf_replace, 1466 .show_fdinfo = bpf_cgroup_link_show_fdinfo, 1467 .fill_link_info = bpf_cgroup_link_fill_link_info, 1468}; 1469 1470#define BPF_F_LINK_ATTACH_MASK \ 1471 (BPF_F_ID | \ 1472 BPF_F_BEFORE | \ 1473 BPF_F_AFTER | \ 1474 BPF_F_PREORDER | \ 1475 BPF_F_LINK) 1476 1477int cgroup_bpf_link_attach(const union bpf_attr *attr, struct bpf_prog *prog) 1478{ 1479 struct bpf_link_primer link_primer; 1480 struct bpf_cgroup_link *link; 1481 struct cgroup *cgrp; 1482 int err; 1483 1484 if (attr->link_create.flags & (~BPF_F_LINK_ATTACH_MASK)) 1485 return -EINVAL; 1486 1487 cgrp = cgroup_get_from_fd(attr->link_create.target_fd); 1488 if (IS_ERR(cgrp)) 1489 return PTR_ERR(cgrp); 1490 1491 link = kzalloc(sizeof(*link), GFP_USER); 1492 if (!link) { 1493 err = -ENOMEM; 1494 goto out_put_cgroup; 1495 } 1496 bpf_link_init(&link->link, BPF_LINK_TYPE_CGROUP, &bpf_cgroup_link_lops, 1497 prog, attr->link_create.attach_type); 1498 link->cgroup = cgrp; 1499 1500 err = bpf_link_prime(&link->link, &link_primer); 1501 if (err) { 1502 kfree(link); 1503 goto out_put_cgroup; 1504 } 1505 1506 err = cgroup_bpf_attach(cgrp, NULL, NULL, link, 1507 link->link.attach_type, BPF_F_ALLOW_MULTI | attr->link_create.flags, 1508 attr->link_create.cgroup.relative_fd, 1509 attr->link_create.cgroup.expected_revision); 1510 if (err) { 1511 bpf_link_cleanup(&link_primer); 1512 goto out_put_cgroup; 1513 } 1514 1515 return bpf_link_settle(&link_primer); 1516 1517out_put_cgroup: 1518 cgroup_put(cgrp); 1519 return err; 1520} 1521 1522int cgroup_bpf_prog_query(const union bpf_attr *attr, 1523 union bpf_attr __user *uattr) 1524{ 1525 struct cgroup *cgrp; 1526 int ret; 1527 1528 cgrp = cgroup_get_from_fd(attr->query.target_fd); 1529 if (IS_ERR(cgrp)) 1530 return PTR_ERR(cgrp); 1531 1532 ret = cgroup_bpf_query(cgrp, attr, uattr); 1533 1534 cgroup_put(cgrp); 1535 return ret; 1536} 1537 1538/** 1539 * __cgroup_bpf_run_filter_skb() - Run a program for packet filtering 1540 * @sk: The socket sending or receiving traffic 1541 * @skb: The skb that is being sent or received 1542 * @atype: The type of program to be executed 1543 * 1544 * If no socket is passed, or the socket is not of type INET or INET6, 1545 * this function does nothing and returns 0. 1546 * 1547 * The program type passed in via @type must be suitable for network 1548 * filtering. No further check is performed to assert that. 1549 * 1550 * For egress packets, this function can return: 1551 * NET_XMIT_SUCCESS (0) - continue with packet output 1552 * NET_XMIT_DROP (1) - drop packet and notify TCP to call cwr 1553 * NET_XMIT_CN (2) - continue with packet output and notify TCP 1554 * to call cwr 1555 * -err - drop packet 1556 * 1557 * For ingress packets, this function will return -EPERM if any 1558 * attached program was found and if it returned != 1 during execution. 1559 * Otherwise 0 is returned. 1560 */ 1561int __cgroup_bpf_run_filter_skb(struct sock *sk, 1562 struct sk_buff *skb, 1563 enum cgroup_bpf_attach_type atype) 1564{ 1565 unsigned int offset = -skb_network_offset(skb); 1566 struct sock *save_sk; 1567 void *saved_data_end; 1568 struct cgroup *cgrp; 1569 int ret; 1570 1571 if (sk->sk_family != AF_INET && sk->sk_family != AF_INET6) 1572 return 0; 1573 1574 cgrp = sock_cgroup_ptr(&sk->sk_cgrp_data); 1575 save_sk = skb->sk; 1576 skb->sk = sk; 1577 __skb_push(skb, offset); 1578 1579 /* compute pointers for the bpf prog */ 1580 bpf_compute_and_save_data_end(skb, &saved_data_end); 1581 1582 if (atype == CGROUP_INET_EGRESS) { 1583 u32 flags = 0; 1584 bool cn; 1585 1586 ret = bpf_prog_run_array_cg(&cgrp->bpf, atype, skb, 1587 __bpf_prog_run_save_cb, 0, &flags); 1588 1589 /* Return values of CGROUP EGRESS BPF programs are: 1590 * 0: drop packet 1591 * 1: keep packet 1592 * 2: drop packet and cn 1593 * 3: keep packet and cn 1594 * 1595 * The returned value is then converted to one of the NET_XMIT 1596 * or an error code that is then interpreted as drop packet 1597 * (and no cn): 1598 * 0: NET_XMIT_SUCCESS skb should be transmitted 1599 * 1: NET_XMIT_DROP skb should be dropped and cn 1600 * 2: NET_XMIT_CN skb should be transmitted and cn 1601 * 3: -err skb should be dropped 1602 */ 1603 1604 cn = flags & BPF_RET_SET_CN; 1605 if (ret && !IS_ERR_VALUE((long)ret)) 1606 ret = -EFAULT; 1607 if (!ret) 1608 ret = (cn ? NET_XMIT_CN : NET_XMIT_SUCCESS); 1609 else 1610 ret = (cn ? NET_XMIT_DROP : ret); 1611 } else { 1612 ret = bpf_prog_run_array_cg(&cgrp->bpf, atype, 1613 skb, __bpf_prog_run_save_cb, 0, 1614 NULL); 1615 if (ret && !IS_ERR_VALUE((long)ret)) 1616 ret = -EFAULT; 1617 } 1618 bpf_restore_data_end(skb, saved_data_end); 1619 __skb_pull(skb, offset); 1620 skb->sk = save_sk; 1621 1622 return ret; 1623} 1624EXPORT_SYMBOL(__cgroup_bpf_run_filter_skb); 1625 1626/** 1627 * __cgroup_bpf_run_filter_sk() - Run a program on a sock 1628 * @sk: sock structure to manipulate 1629 * @atype: The type of program to be executed 1630 * 1631 * socket is passed is expected to be of type INET or INET6. 1632 * 1633 * The program type passed in via @type must be suitable for sock 1634 * filtering. No further check is performed to assert that. 1635 * 1636 * This function will return %-EPERM if any if an attached program was found 1637 * and if it returned != 1 during execution. In all other cases, 0 is returned. 1638 */ 1639int __cgroup_bpf_run_filter_sk(struct sock *sk, 1640 enum cgroup_bpf_attach_type atype) 1641{ 1642 struct cgroup *cgrp = sock_cgroup_ptr(&sk->sk_cgrp_data); 1643 1644 return bpf_prog_run_array_cg(&cgrp->bpf, atype, sk, bpf_prog_run, 0, 1645 NULL); 1646} 1647EXPORT_SYMBOL(__cgroup_bpf_run_filter_sk); 1648 1649/** 1650 * __cgroup_bpf_run_filter_sock_addr() - Run a program on a sock and 1651 * provided by user sockaddr 1652 * @sk: sock struct that will use sockaddr 1653 * @uaddr: sockaddr struct provided by user 1654 * @uaddrlen: Pointer to the size of the sockaddr struct provided by user. It is 1655 * read-only for AF_INET[6] uaddr but can be modified for AF_UNIX 1656 * uaddr. 1657 * @atype: The type of program to be executed 1658 * @t_ctx: Pointer to attach type specific context 1659 * @flags: Pointer to u32 which contains higher bits of BPF program 1660 * return value (OR'ed together). 1661 * 1662 * socket is expected to be of type INET, INET6 or UNIX. 1663 * 1664 * This function will return %-EPERM if an attached program is found and 1665 * returned value != 1 during execution. In all other cases, 0 is returned. 1666 */ 1667int __cgroup_bpf_run_filter_sock_addr(struct sock *sk, 1668 struct sockaddr_unsized *uaddr, 1669 int *uaddrlen, 1670 enum cgroup_bpf_attach_type atype, 1671 void *t_ctx, 1672 u32 *flags) 1673{ 1674 struct bpf_sock_addr_kern ctx = { 1675 .sk = sk, 1676 .uaddr = uaddr, 1677 .t_ctx = t_ctx, 1678 }; 1679 struct sockaddr_storage storage; 1680 struct cgroup *cgrp; 1681 int ret; 1682 1683 /* Check socket family since not all sockets represent network 1684 * endpoint (e.g. AF_UNIX). 1685 */ 1686 if (sk->sk_family != AF_INET && sk->sk_family != AF_INET6 && 1687 sk->sk_family != AF_UNIX) 1688 return 0; 1689 1690 if (!ctx.uaddr) { 1691 memset(&storage, 0, sizeof(storage)); 1692 ctx.uaddr = (struct sockaddr_unsized *)&storage; 1693 ctx.uaddrlen = 0; 1694 } else { 1695 ctx.uaddrlen = *uaddrlen; 1696 } 1697 1698 cgrp = sock_cgroup_ptr(&sk->sk_cgrp_data); 1699 ret = bpf_prog_run_array_cg(&cgrp->bpf, atype, &ctx, bpf_prog_run, 1700 0, flags); 1701 1702 if (!ret && uaddr) 1703 *uaddrlen = ctx.uaddrlen; 1704 1705 return ret; 1706} 1707EXPORT_SYMBOL(__cgroup_bpf_run_filter_sock_addr); 1708 1709/** 1710 * __cgroup_bpf_run_filter_sock_ops() - Run a program on a sock 1711 * @sk: socket to get cgroup from 1712 * @sock_ops: bpf_sock_ops_kern struct to pass to program. Contains 1713 * sk with connection information (IP addresses, etc.) May not contain 1714 * cgroup info if it is a req sock. 1715 * @atype: The type of program to be executed 1716 * 1717 * socket passed is expected to be of type INET or INET6. 1718 * 1719 * The program type passed in via @type must be suitable for sock_ops 1720 * filtering. No further check is performed to assert that. 1721 * 1722 * This function will return %-EPERM if any if an attached program was found 1723 * and if it returned != 1 during execution. In all other cases, 0 is returned. 1724 */ 1725int __cgroup_bpf_run_filter_sock_ops(struct sock *sk, 1726 struct bpf_sock_ops_kern *sock_ops, 1727 enum cgroup_bpf_attach_type atype) 1728{ 1729 struct cgroup *cgrp = sock_cgroup_ptr(&sk->sk_cgrp_data); 1730 1731 return bpf_prog_run_array_cg(&cgrp->bpf, atype, sock_ops, bpf_prog_run, 1732 0, NULL); 1733} 1734EXPORT_SYMBOL(__cgroup_bpf_run_filter_sock_ops); 1735 1736int __cgroup_bpf_check_dev_permission(short dev_type, u32 major, u32 minor, 1737 short access, enum cgroup_bpf_attach_type atype) 1738{ 1739 struct cgroup *cgrp; 1740 struct bpf_cgroup_dev_ctx ctx = { 1741 .access_type = (access << 16) | dev_type, 1742 .major = major, 1743 .minor = minor, 1744 }; 1745 int ret; 1746 1747 rcu_read_lock(); 1748 cgrp = task_dfl_cgroup(current); 1749 ret = bpf_prog_run_array_cg(&cgrp->bpf, atype, &ctx, bpf_prog_run, 0, 1750 NULL); 1751 rcu_read_unlock(); 1752 1753 return ret; 1754} 1755 1756BPF_CALL_2(bpf_get_local_storage, struct bpf_map *, map, u64, flags) 1757{ 1758 /* flags argument is not used now, 1759 * but provides an ability to extend the API. 1760 * verifier checks that its value is correct. 1761 */ 1762 enum bpf_cgroup_storage_type stype = cgroup_storage_type(map); 1763 struct bpf_cgroup_storage *storage; 1764 struct bpf_cg_run_ctx *ctx; 1765 void *ptr; 1766 1767 /* get current cgroup storage from BPF run context */ 1768 ctx = container_of(current->bpf_ctx, struct bpf_cg_run_ctx, run_ctx); 1769 storage = ctx->prog_item->cgroup_storage[stype]; 1770 1771 if (stype == BPF_CGROUP_STORAGE_SHARED) 1772 ptr = &READ_ONCE(storage->buf)->data[0]; 1773 else 1774 ptr = this_cpu_ptr(storage->percpu_buf); 1775 1776 return (unsigned long)ptr; 1777} 1778 1779const struct bpf_func_proto bpf_get_local_storage_proto = { 1780 .func = bpf_get_local_storage, 1781 .gpl_only = false, 1782 .ret_type = RET_PTR_TO_MAP_VALUE, 1783 .arg1_type = ARG_CONST_MAP_PTR, 1784 .arg2_type = ARG_ANYTHING, 1785}; 1786 1787BPF_CALL_0(bpf_get_retval) 1788{ 1789 struct bpf_cg_run_ctx *ctx = 1790 container_of(current->bpf_ctx, struct bpf_cg_run_ctx, run_ctx); 1791 1792 return ctx->retval; 1793} 1794 1795const struct bpf_func_proto bpf_get_retval_proto = { 1796 .func = bpf_get_retval, 1797 .gpl_only = false, 1798 .ret_type = RET_INTEGER, 1799}; 1800 1801BPF_CALL_1(bpf_set_retval, int, retval) 1802{ 1803 struct bpf_cg_run_ctx *ctx = 1804 container_of(current->bpf_ctx, struct bpf_cg_run_ctx, run_ctx); 1805 1806 ctx->retval = retval; 1807 return 0; 1808} 1809 1810const struct bpf_func_proto bpf_set_retval_proto = { 1811 .func = bpf_set_retval, 1812 .gpl_only = false, 1813 .ret_type = RET_INTEGER, 1814 .arg1_type = ARG_ANYTHING, 1815}; 1816 1817static const struct bpf_func_proto * 1818cgroup_dev_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog) 1819{ 1820 const struct bpf_func_proto *func_proto; 1821 1822 func_proto = cgroup_common_func_proto(func_id, prog); 1823 if (func_proto) 1824 return func_proto; 1825 1826 switch (func_id) { 1827 case BPF_FUNC_perf_event_output: 1828 return &bpf_event_output_data_proto; 1829 default: 1830 return bpf_base_func_proto(func_id, prog); 1831 } 1832} 1833 1834static bool cgroup_dev_is_valid_access(int off, int size, 1835 enum bpf_access_type type, 1836 const struct bpf_prog *prog, 1837 struct bpf_insn_access_aux *info) 1838{ 1839 const int size_default = sizeof(__u32); 1840 1841 if (type == BPF_WRITE) 1842 return false; 1843 1844 if (off < 0 || off + size > sizeof(struct bpf_cgroup_dev_ctx)) 1845 return false; 1846 /* The verifier guarantees that size > 0. */ 1847 if (off % size != 0) 1848 return false; 1849 1850 switch (off) { 1851 case bpf_ctx_range(struct bpf_cgroup_dev_ctx, access_type): 1852 bpf_ctx_record_field_size(info, size_default); 1853 if (!bpf_ctx_narrow_access_ok(off, size, size_default)) 1854 return false; 1855 break; 1856 default: 1857 if (size != size_default) 1858 return false; 1859 } 1860 1861 return true; 1862} 1863 1864const struct bpf_prog_ops cg_dev_prog_ops = { 1865}; 1866 1867const struct bpf_verifier_ops cg_dev_verifier_ops = { 1868 .get_func_proto = cgroup_dev_func_proto, 1869 .is_valid_access = cgroup_dev_is_valid_access, 1870}; 1871 1872/** 1873 * __cgroup_bpf_run_filter_sysctl - Run a program on sysctl 1874 * 1875 * @head: sysctl table header 1876 * @table: sysctl table 1877 * @write: sysctl is being read (= 0) or written (= 1) 1878 * @buf: pointer to buffer (in and out) 1879 * @pcount: value-result argument: value is size of buffer pointed to by @buf, 1880 * result is size of @new_buf if program set new value, initial value 1881 * otherwise 1882 * @ppos: value-result argument: value is position at which read from or write 1883 * to sysctl is happening, result is new position if program overrode it, 1884 * initial value otherwise 1885 * @atype: type of program to be executed 1886 * 1887 * Program is run when sysctl is being accessed, either read or written, and 1888 * can allow or deny such access. 1889 * 1890 * This function will return %-EPERM if an attached program is found and 1891 * returned value != 1 during execution. In all other cases 0 is returned. 1892 */ 1893int __cgroup_bpf_run_filter_sysctl(struct ctl_table_header *head, 1894 const struct ctl_table *table, int write, 1895 char **buf, size_t *pcount, loff_t *ppos, 1896 enum cgroup_bpf_attach_type atype) 1897{ 1898 struct bpf_sysctl_kern ctx = { 1899 .head = head, 1900 .table = table, 1901 .write = write, 1902 .ppos = ppos, 1903 .cur_val = NULL, 1904 .cur_len = PAGE_SIZE, 1905 .new_val = NULL, 1906 .new_len = 0, 1907 .new_updated = 0, 1908 }; 1909 struct cgroup *cgrp; 1910 loff_t pos = 0; 1911 int ret; 1912 1913 ctx.cur_val = kmalloc_track_caller(ctx.cur_len, GFP_KERNEL); 1914 if (!ctx.cur_val || 1915 table->proc_handler(table, 0, ctx.cur_val, &ctx.cur_len, &pos)) { 1916 /* Let BPF program decide how to proceed. */ 1917 ctx.cur_len = 0; 1918 } 1919 1920 if (write && *buf && *pcount) { 1921 /* BPF program should be able to override new value with a 1922 * buffer bigger than provided by user. 1923 */ 1924 ctx.new_val = kmalloc_track_caller(PAGE_SIZE, GFP_KERNEL); 1925 ctx.new_len = min_t(size_t, PAGE_SIZE, *pcount); 1926 if (ctx.new_val) { 1927 memcpy(ctx.new_val, *buf, ctx.new_len); 1928 } else { 1929 /* Let BPF program decide how to proceed. */ 1930 ctx.new_len = 0; 1931 } 1932 } 1933 1934 rcu_read_lock(); 1935 cgrp = task_dfl_cgroup(current); 1936 ret = bpf_prog_run_array_cg(&cgrp->bpf, atype, &ctx, bpf_prog_run, 0, 1937 NULL); 1938 rcu_read_unlock(); 1939 1940 kfree(ctx.cur_val); 1941 1942 if (ret == 1 && ctx.new_updated) { 1943 kfree(*buf); 1944 *buf = ctx.new_val; 1945 *pcount = ctx.new_len; 1946 } else { 1947 kfree(ctx.new_val); 1948 } 1949 1950 return ret; 1951} 1952 1953#ifdef CONFIG_NET 1954static int sockopt_alloc_buf(struct bpf_sockopt_kern *ctx, int max_optlen, 1955 struct bpf_sockopt_buf *buf) 1956{ 1957 if (unlikely(max_optlen < 0)) 1958 return -EINVAL; 1959 1960 if (unlikely(max_optlen > PAGE_SIZE)) { 1961 /* We don't expose optvals that are greater than PAGE_SIZE 1962 * to the BPF program. 1963 */ 1964 max_optlen = PAGE_SIZE; 1965 } 1966 1967 if (max_optlen <= sizeof(buf->data)) { 1968 /* When the optval fits into BPF_SOCKOPT_KERN_BUF_SIZE 1969 * bytes avoid the cost of kzalloc. 1970 */ 1971 ctx->optval = buf->data; 1972 ctx->optval_end = ctx->optval + max_optlen; 1973 return max_optlen; 1974 } 1975 1976 ctx->optval = kzalloc(max_optlen, GFP_USER); 1977 if (!ctx->optval) 1978 return -ENOMEM; 1979 1980 ctx->optval_end = ctx->optval + max_optlen; 1981 1982 return max_optlen; 1983} 1984 1985static void sockopt_free_buf(struct bpf_sockopt_kern *ctx, 1986 struct bpf_sockopt_buf *buf) 1987{ 1988 if (ctx->optval == buf->data) 1989 return; 1990 kfree(ctx->optval); 1991} 1992 1993static bool sockopt_buf_allocated(struct bpf_sockopt_kern *ctx, 1994 struct bpf_sockopt_buf *buf) 1995{ 1996 return ctx->optval != buf->data; 1997} 1998 1999int __cgroup_bpf_run_filter_setsockopt(struct sock *sk, int *level, 2000 int *optname, sockptr_t optval, 2001 int *optlen, char **kernel_optval) 2002{ 2003 struct cgroup *cgrp = sock_cgroup_ptr(&sk->sk_cgrp_data); 2004 struct bpf_sockopt_buf buf = {}; 2005 struct bpf_sockopt_kern ctx = { 2006 .sk = sk, 2007 .level = *level, 2008 .optname = *optname, 2009 }; 2010 int ret, max_optlen; 2011 2012 /* Allocate a bit more than the initial user buffer for 2013 * BPF program. The canonical use case is overriding 2014 * TCP_CONGESTION(nv) to TCP_CONGESTION(cubic). 2015 */ 2016 max_optlen = max_t(int, 16, *optlen); 2017 max_optlen = sockopt_alloc_buf(&ctx, max_optlen, &buf); 2018 if (max_optlen < 0) 2019 return max_optlen; 2020 2021 ctx.optlen = *optlen; 2022 2023 if (copy_from_sockptr(ctx.optval, optval, 2024 min(*optlen, max_optlen))) { 2025 ret = -EFAULT; 2026 goto out; 2027 } 2028 2029 lock_sock(sk); 2030 ret = bpf_prog_run_array_cg(&cgrp->bpf, CGROUP_SETSOCKOPT, 2031 &ctx, bpf_prog_run, 0, NULL); 2032 release_sock(sk); 2033 2034 if (ret) 2035 goto out; 2036 2037 if (ctx.optlen == -1) { 2038 /* optlen set to -1, bypass kernel */ 2039 ret = 1; 2040 } else if (ctx.optlen > max_optlen || ctx.optlen < -1) { 2041 /* optlen is out of bounds */ 2042 if (*optlen > PAGE_SIZE && ctx.optlen >= 0) { 2043 pr_info_once("bpf setsockopt: ignoring program buffer with optlen=%d (max_optlen=%d)\n", 2044 ctx.optlen, max_optlen); 2045 ret = 0; 2046 goto out; 2047 } 2048 ret = -EFAULT; 2049 } else { 2050 /* optlen within bounds, run kernel handler */ 2051 ret = 0; 2052 2053 /* export any potential modifications */ 2054 *level = ctx.level; 2055 *optname = ctx.optname; 2056 2057 /* optlen == 0 from BPF indicates that we should 2058 * use original userspace data. 2059 */ 2060 if (ctx.optlen != 0) { 2061 *optlen = ctx.optlen; 2062 /* We've used bpf_sockopt_kern->buf as an intermediary 2063 * storage, but the BPF program indicates that we need 2064 * to pass this data to the kernel setsockopt handler. 2065 * No way to export on-stack buf, have to allocate a 2066 * new buffer. 2067 */ 2068 if (!sockopt_buf_allocated(&ctx, &buf)) { 2069 void *p = kmalloc(ctx.optlen, GFP_USER); 2070 2071 if (!p) { 2072 ret = -ENOMEM; 2073 goto out; 2074 } 2075 memcpy(p, ctx.optval, ctx.optlen); 2076 *kernel_optval = p; 2077 } else { 2078 *kernel_optval = ctx.optval; 2079 } 2080 /* export and don't free sockopt buf */ 2081 return 0; 2082 } 2083 } 2084 2085out: 2086 sockopt_free_buf(&ctx, &buf); 2087 return ret; 2088} 2089 2090int __cgroup_bpf_run_filter_getsockopt(struct sock *sk, int level, 2091 int optname, sockptr_t optval, 2092 sockptr_t optlen, int max_optlen, 2093 int retval) 2094{ 2095 struct cgroup *cgrp = sock_cgroup_ptr(&sk->sk_cgrp_data); 2096 struct bpf_sockopt_buf buf = {}; 2097 struct bpf_sockopt_kern ctx = { 2098 .sk = sk, 2099 .level = level, 2100 .optname = optname, 2101 .current_task = current, 2102 }; 2103 int orig_optlen; 2104 int ret; 2105 2106 orig_optlen = max_optlen; 2107 ctx.optlen = max_optlen; 2108 max_optlen = sockopt_alloc_buf(&ctx, max_optlen, &buf); 2109 if (max_optlen < 0) 2110 return max_optlen; 2111 2112 if (!retval) { 2113 /* If kernel getsockopt finished successfully, 2114 * copy whatever was returned to the user back 2115 * into our temporary buffer. Set optlen to the 2116 * one that kernel returned as well to let 2117 * BPF programs inspect the value. 2118 */ 2119 if (copy_from_sockptr(&ctx.optlen, optlen, 2120 sizeof(ctx.optlen))) { 2121 ret = -EFAULT; 2122 goto out; 2123 } 2124 2125 if (ctx.optlen < 0) { 2126 ret = -EFAULT; 2127 goto out; 2128 } 2129 orig_optlen = ctx.optlen; 2130 2131 if (copy_from_sockptr(ctx.optval, optval, 2132 min(ctx.optlen, max_optlen))) { 2133 ret = -EFAULT; 2134 goto out; 2135 } 2136 } 2137 2138 lock_sock(sk); 2139 ret = bpf_prog_run_array_cg(&cgrp->bpf, CGROUP_GETSOCKOPT, 2140 &ctx, bpf_prog_run, retval, NULL); 2141 release_sock(sk); 2142 2143 if (ret < 0) 2144 goto out; 2145 2146 if (!sockptr_is_null(optval) && 2147 (ctx.optlen > max_optlen || ctx.optlen < 0)) { 2148 if (orig_optlen > PAGE_SIZE && ctx.optlen >= 0) { 2149 pr_info_once("bpf getsockopt: ignoring program buffer with optlen=%d (max_optlen=%d)\n", 2150 ctx.optlen, max_optlen); 2151 ret = retval; 2152 goto out; 2153 } 2154 ret = -EFAULT; 2155 goto out; 2156 } 2157 2158 if (ctx.optlen != 0) { 2159 if (!sockptr_is_null(optval) && 2160 copy_to_sockptr(optval, ctx.optval, ctx.optlen)) { 2161 ret = -EFAULT; 2162 goto out; 2163 } 2164 if (copy_to_sockptr(optlen, &ctx.optlen, sizeof(ctx.optlen))) { 2165 ret = -EFAULT; 2166 goto out; 2167 } 2168 } 2169 2170out: 2171 sockopt_free_buf(&ctx, &buf); 2172 return ret; 2173} 2174 2175int __cgroup_bpf_run_filter_getsockopt_kern(struct sock *sk, int level, 2176 int optname, void *optval, 2177 int *optlen, int retval) 2178{ 2179 struct cgroup *cgrp = sock_cgroup_ptr(&sk->sk_cgrp_data); 2180 struct bpf_sockopt_kern ctx = { 2181 .sk = sk, 2182 .level = level, 2183 .optname = optname, 2184 .optlen = *optlen, 2185 .optval = optval, 2186 .optval_end = optval + *optlen, 2187 .current_task = current, 2188 }; 2189 int ret; 2190 2191 /* Note that __cgroup_bpf_run_filter_getsockopt doesn't copy 2192 * user data back into BPF buffer when reval != 0. This is 2193 * done as an optimization to avoid extra copy, assuming 2194 * kernel won't populate the data in case of an error. 2195 * Here we always pass the data and memset() should 2196 * be called if that data shouldn't be "exported". 2197 */ 2198 2199 ret = bpf_prog_run_array_cg(&cgrp->bpf, CGROUP_GETSOCKOPT, 2200 &ctx, bpf_prog_run, retval, NULL); 2201 if (ret < 0) 2202 return ret; 2203 2204 if (ctx.optlen > *optlen) 2205 return -EFAULT; 2206 2207 /* BPF programs can shrink the buffer, export the modifications. 2208 */ 2209 if (ctx.optlen != 0) 2210 *optlen = ctx.optlen; 2211 2212 return ret; 2213} 2214#endif 2215 2216static ssize_t sysctl_cpy_dir(const struct ctl_dir *dir, char **bufp, 2217 size_t *lenp) 2218{ 2219 ssize_t tmp_ret = 0, ret; 2220 2221 if (dir->header.parent) { 2222 tmp_ret = sysctl_cpy_dir(dir->header.parent, bufp, lenp); 2223 if (tmp_ret < 0) 2224 return tmp_ret; 2225 } 2226 2227 ret = strscpy(*bufp, dir->header.ctl_table[0].procname, *lenp); 2228 if (ret < 0) 2229 return ret; 2230 *bufp += ret; 2231 *lenp -= ret; 2232 ret += tmp_ret; 2233 2234 /* Avoid leading slash. */ 2235 if (!ret) 2236 return ret; 2237 2238 tmp_ret = strscpy(*bufp, "/", *lenp); 2239 if (tmp_ret < 0) 2240 return tmp_ret; 2241 *bufp += tmp_ret; 2242 *lenp -= tmp_ret; 2243 2244 return ret + tmp_ret; 2245} 2246 2247BPF_CALL_4(bpf_sysctl_get_name, struct bpf_sysctl_kern *, ctx, char *, buf, 2248 size_t, buf_len, u64, flags) 2249{ 2250 ssize_t tmp_ret = 0, ret; 2251 2252 if (!buf) 2253 return -EINVAL; 2254 2255 if (!(flags & BPF_F_SYSCTL_BASE_NAME)) { 2256 if (!ctx->head) 2257 return -EINVAL; 2258 tmp_ret = sysctl_cpy_dir(ctx->head->parent, &buf, &buf_len); 2259 if (tmp_ret < 0) 2260 return tmp_ret; 2261 } 2262 2263 ret = strscpy(buf, ctx->table->procname, buf_len); 2264 2265 return ret < 0 ? ret : tmp_ret + ret; 2266} 2267 2268static const struct bpf_func_proto bpf_sysctl_get_name_proto = { 2269 .func = bpf_sysctl_get_name, 2270 .gpl_only = false, 2271 .ret_type = RET_INTEGER, 2272 .arg1_type = ARG_PTR_TO_CTX, 2273 .arg2_type = ARG_PTR_TO_MEM | MEM_WRITE, 2274 .arg3_type = ARG_CONST_SIZE, 2275 .arg4_type = ARG_ANYTHING, 2276}; 2277 2278static int copy_sysctl_value(char *dst, size_t dst_len, char *src, 2279 size_t src_len) 2280{ 2281 if (!dst) 2282 return -EINVAL; 2283 2284 if (!dst_len) 2285 return -E2BIG; 2286 2287 if (!src || !src_len) { 2288 memset(dst, 0, dst_len); 2289 return -EINVAL; 2290 } 2291 2292 memcpy(dst, src, min(dst_len, src_len)); 2293 2294 if (dst_len > src_len) { 2295 memset(dst + src_len, '\0', dst_len - src_len); 2296 return src_len; 2297 } 2298 2299 dst[dst_len - 1] = '\0'; 2300 2301 return -E2BIG; 2302} 2303 2304BPF_CALL_3(bpf_sysctl_get_current_value, struct bpf_sysctl_kern *, ctx, 2305 char *, buf, size_t, buf_len) 2306{ 2307 return copy_sysctl_value(buf, buf_len, ctx->cur_val, ctx->cur_len); 2308} 2309 2310static const struct bpf_func_proto bpf_sysctl_get_current_value_proto = { 2311 .func = bpf_sysctl_get_current_value, 2312 .gpl_only = false, 2313 .ret_type = RET_INTEGER, 2314 .arg1_type = ARG_PTR_TO_CTX, 2315 .arg2_type = ARG_PTR_TO_UNINIT_MEM, 2316 .arg3_type = ARG_CONST_SIZE, 2317}; 2318 2319BPF_CALL_3(bpf_sysctl_get_new_value, struct bpf_sysctl_kern *, ctx, char *, buf, 2320 size_t, buf_len) 2321{ 2322 if (!ctx->write) { 2323 if (buf && buf_len) 2324 memset(buf, '\0', buf_len); 2325 return -EINVAL; 2326 } 2327 return copy_sysctl_value(buf, buf_len, ctx->new_val, ctx->new_len); 2328} 2329 2330static const struct bpf_func_proto bpf_sysctl_get_new_value_proto = { 2331 .func = bpf_sysctl_get_new_value, 2332 .gpl_only = false, 2333 .ret_type = RET_INTEGER, 2334 .arg1_type = ARG_PTR_TO_CTX, 2335 .arg2_type = ARG_PTR_TO_UNINIT_MEM, 2336 .arg3_type = ARG_CONST_SIZE, 2337}; 2338 2339BPF_CALL_3(bpf_sysctl_set_new_value, struct bpf_sysctl_kern *, ctx, 2340 const char *, buf, size_t, buf_len) 2341{ 2342 if (!ctx->write || !ctx->new_val || !ctx->new_len || !buf || !buf_len) 2343 return -EINVAL; 2344 2345 if (buf_len > PAGE_SIZE - 1) 2346 return -E2BIG; 2347 2348 memcpy(ctx->new_val, buf, buf_len); 2349 ctx->new_len = buf_len; 2350 ctx->new_updated = 1; 2351 2352 return 0; 2353} 2354 2355static const struct bpf_func_proto bpf_sysctl_set_new_value_proto = { 2356 .func = bpf_sysctl_set_new_value, 2357 .gpl_only = false, 2358 .ret_type = RET_INTEGER, 2359 .arg1_type = ARG_PTR_TO_CTX, 2360 .arg2_type = ARG_PTR_TO_MEM | MEM_RDONLY, 2361 .arg3_type = ARG_CONST_SIZE, 2362}; 2363 2364static const struct bpf_func_proto * 2365sysctl_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog) 2366{ 2367 const struct bpf_func_proto *func_proto; 2368 2369 func_proto = cgroup_common_func_proto(func_id, prog); 2370 if (func_proto) 2371 return func_proto; 2372 2373 switch (func_id) { 2374 case BPF_FUNC_sysctl_get_name: 2375 return &bpf_sysctl_get_name_proto; 2376 case BPF_FUNC_sysctl_get_current_value: 2377 return &bpf_sysctl_get_current_value_proto; 2378 case BPF_FUNC_sysctl_get_new_value: 2379 return &bpf_sysctl_get_new_value_proto; 2380 case BPF_FUNC_sysctl_set_new_value: 2381 return &bpf_sysctl_set_new_value_proto; 2382 case BPF_FUNC_ktime_get_coarse_ns: 2383 return &bpf_ktime_get_coarse_ns_proto; 2384 case BPF_FUNC_perf_event_output: 2385 return &bpf_event_output_data_proto; 2386 default: 2387 return bpf_base_func_proto(func_id, prog); 2388 } 2389} 2390 2391static bool sysctl_is_valid_access(int off, int size, enum bpf_access_type type, 2392 const struct bpf_prog *prog, 2393 struct bpf_insn_access_aux *info) 2394{ 2395 const int size_default = sizeof(__u32); 2396 2397 if (off < 0 || off + size > sizeof(struct bpf_sysctl) || off % size) 2398 return false; 2399 2400 switch (off) { 2401 case bpf_ctx_range(struct bpf_sysctl, write): 2402 if (type != BPF_READ) 2403 return false; 2404 bpf_ctx_record_field_size(info, size_default); 2405 return bpf_ctx_narrow_access_ok(off, size, size_default); 2406 case bpf_ctx_range(struct bpf_sysctl, file_pos): 2407 if (type == BPF_READ) { 2408 bpf_ctx_record_field_size(info, size_default); 2409 return bpf_ctx_narrow_access_ok(off, size, size_default); 2410 } else { 2411 return size == size_default; 2412 } 2413 default: 2414 return false; 2415 } 2416} 2417 2418static u32 sysctl_convert_ctx_access(enum bpf_access_type type, 2419 const struct bpf_insn *si, 2420 struct bpf_insn *insn_buf, 2421 struct bpf_prog *prog, u32 *target_size) 2422{ 2423 struct bpf_insn *insn = insn_buf; 2424 u32 read_size; 2425 2426 switch (si->off) { 2427 case offsetof(struct bpf_sysctl, write): 2428 *insn++ = BPF_LDX_MEM( 2429 BPF_SIZE(si->code), si->dst_reg, si->src_reg, 2430 bpf_target_off(struct bpf_sysctl_kern, write, 2431 sizeof_field(struct bpf_sysctl_kern, 2432 write), 2433 target_size)); 2434 break; 2435 case offsetof(struct bpf_sysctl, file_pos): 2436 /* ppos is a pointer so it should be accessed via indirect 2437 * loads and stores. Also for stores additional temporary 2438 * register is used since neither src_reg nor dst_reg can be 2439 * overridden. 2440 */ 2441 if (type == BPF_WRITE) { 2442 int treg = BPF_REG_9; 2443 2444 if (si->src_reg == treg || si->dst_reg == treg) 2445 --treg; 2446 if (si->src_reg == treg || si->dst_reg == treg) 2447 --treg; 2448 *insn++ = BPF_STX_MEM( 2449 BPF_DW, si->dst_reg, treg, 2450 offsetof(struct bpf_sysctl_kern, tmp_reg)); 2451 *insn++ = BPF_LDX_MEM( 2452 BPF_FIELD_SIZEOF(struct bpf_sysctl_kern, ppos), 2453 treg, si->dst_reg, 2454 offsetof(struct bpf_sysctl_kern, ppos)); 2455 *insn++ = BPF_RAW_INSN( 2456 BPF_CLASS(si->code) | BPF_MEM | BPF_SIZEOF(u32), 2457 treg, si->src_reg, 2458 bpf_ctx_narrow_access_offset( 2459 0, sizeof(u32), sizeof(loff_t)), 2460 si->imm); 2461 *insn++ = BPF_LDX_MEM( 2462 BPF_DW, treg, si->dst_reg, 2463 offsetof(struct bpf_sysctl_kern, tmp_reg)); 2464 } else { 2465 *insn++ = BPF_LDX_MEM( 2466 BPF_FIELD_SIZEOF(struct bpf_sysctl_kern, ppos), 2467 si->dst_reg, si->src_reg, 2468 offsetof(struct bpf_sysctl_kern, ppos)); 2469 read_size = bpf_size_to_bytes(BPF_SIZE(si->code)); 2470 *insn++ = BPF_LDX_MEM( 2471 BPF_SIZE(si->code), si->dst_reg, si->dst_reg, 2472 bpf_ctx_narrow_access_offset( 2473 0, read_size, sizeof(loff_t))); 2474 } 2475 *target_size = sizeof(u32); 2476 break; 2477 } 2478 2479 return insn - insn_buf; 2480} 2481 2482const struct bpf_verifier_ops cg_sysctl_verifier_ops = { 2483 .get_func_proto = sysctl_func_proto, 2484 .is_valid_access = sysctl_is_valid_access, 2485 .convert_ctx_access = sysctl_convert_ctx_access, 2486}; 2487 2488const struct bpf_prog_ops cg_sysctl_prog_ops = { 2489}; 2490 2491#ifdef CONFIG_NET 2492BPF_CALL_1(bpf_get_netns_cookie_sockopt, struct bpf_sockopt_kern *, ctx) 2493{ 2494 const struct net *net = ctx ? sock_net(ctx->sk) : &init_net; 2495 2496 return net->net_cookie; 2497} 2498 2499static const struct bpf_func_proto bpf_get_netns_cookie_sockopt_proto = { 2500 .func = bpf_get_netns_cookie_sockopt, 2501 .gpl_only = false, 2502 .ret_type = RET_INTEGER, 2503 .arg1_type = ARG_PTR_TO_CTX_OR_NULL, 2504}; 2505#endif 2506 2507static const struct bpf_func_proto * 2508cg_sockopt_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog) 2509{ 2510 const struct bpf_func_proto *func_proto; 2511 2512 func_proto = cgroup_common_func_proto(func_id, prog); 2513 if (func_proto) 2514 return func_proto; 2515 2516 switch (func_id) { 2517#ifdef CONFIG_NET 2518 case BPF_FUNC_get_netns_cookie: 2519 return &bpf_get_netns_cookie_sockopt_proto; 2520 case BPF_FUNC_sk_storage_get: 2521 return &bpf_sk_storage_get_proto; 2522 case BPF_FUNC_sk_storage_delete: 2523 return &bpf_sk_storage_delete_proto; 2524 case BPF_FUNC_setsockopt: 2525 if (prog->expected_attach_type == BPF_CGROUP_SETSOCKOPT) 2526 return &bpf_sk_setsockopt_proto; 2527 return NULL; 2528 case BPF_FUNC_getsockopt: 2529 if (prog->expected_attach_type == BPF_CGROUP_SETSOCKOPT) 2530 return &bpf_sk_getsockopt_proto; 2531 return NULL; 2532#endif 2533#ifdef CONFIG_INET 2534 case BPF_FUNC_tcp_sock: 2535 return &bpf_tcp_sock_proto; 2536#endif 2537 case BPF_FUNC_perf_event_output: 2538 return &bpf_event_output_data_proto; 2539 default: 2540 return bpf_base_func_proto(func_id, prog); 2541 } 2542} 2543 2544static bool cg_sockopt_is_valid_access(int off, int size, 2545 enum bpf_access_type type, 2546 const struct bpf_prog *prog, 2547 struct bpf_insn_access_aux *info) 2548{ 2549 const int size_default = sizeof(__u32); 2550 2551 if (off < 0 || off >= sizeof(struct bpf_sockopt)) 2552 return false; 2553 2554 if (off % size != 0) 2555 return false; 2556 2557 if (type == BPF_WRITE) { 2558 switch (off) { 2559 case offsetof(struct bpf_sockopt, retval): 2560 if (size != size_default) 2561 return false; 2562 return prog->expected_attach_type == 2563 BPF_CGROUP_GETSOCKOPT; 2564 case offsetof(struct bpf_sockopt, optname): 2565 fallthrough; 2566 case offsetof(struct bpf_sockopt, level): 2567 if (size != size_default) 2568 return false; 2569 return prog->expected_attach_type == 2570 BPF_CGROUP_SETSOCKOPT; 2571 case offsetof(struct bpf_sockopt, optlen): 2572 return size == size_default; 2573 default: 2574 return false; 2575 } 2576 } 2577 2578 switch (off) { 2579 case bpf_ctx_range_ptr(struct bpf_sockopt, sk): 2580 if (size != sizeof(__u64)) 2581 return false; 2582 info->reg_type = PTR_TO_SOCKET; 2583 break; 2584 case bpf_ctx_range_ptr(struct bpf_sockopt, optval): 2585 if (size != sizeof(__u64)) 2586 return false; 2587 info->reg_type = PTR_TO_PACKET; 2588 break; 2589 case bpf_ctx_range_ptr(struct bpf_sockopt, optval_end): 2590 if (size != sizeof(__u64)) 2591 return false; 2592 info->reg_type = PTR_TO_PACKET_END; 2593 break; 2594 case bpf_ctx_range(struct bpf_sockopt, retval): 2595 if (size != size_default) 2596 return false; 2597 return prog->expected_attach_type == BPF_CGROUP_GETSOCKOPT; 2598 default: 2599 if (size != size_default) 2600 return false; 2601 break; 2602 } 2603 return true; 2604} 2605 2606#define CG_SOCKOPT_READ_FIELD(F) \ 2607 BPF_LDX_MEM(BPF_FIELD_SIZEOF(struct bpf_sockopt_kern, F), \ 2608 si->dst_reg, si->src_reg, \ 2609 offsetof(struct bpf_sockopt_kern, F)) 2610 2611#define CG_SOCKOPT_WRITE_FIELD(F) \ 2612 BPF_RAW_INSN((BPF_FIELD_SIZEOF(struct bpf_sockopt_kern, F) | \ 2613 BPF_MEM | BPF_CLASS(si->code)), \ 2614 si->dst_reg, si->src_reg, \ 2615 offsetof(struct bpf_sockopt_kern, F), \ 2616 si->imm) 2617 2618static u32 cg_sockopt_convert_ctx_access(enum bpf_access_type type, 2619 const struct bpf_insn *si, 2620 struct bpf_insn *insn_buf, 2621 struct bpf_prog *prog, 2622 u32 *target_size) 2623{ 2624 struct bpf_insn *insn = insn_buf; 2625 2626 switch (si->off) { 2627 case offsetof(struct bpf_sockopt, sk): 2628 *insn++ = CG_SOCKOPT_READ_FIELD(sk); 2629 break; 2630 case offsetof(struct bpf_sockopt, level): 2631 if (type == BPF_WRITE) 2632 *insn++ = CG_SOCKOPT_WRITE_FIELD(level); 2633 else 2634 *insn++ = CG_SOCKOPT_READ_FIELD(level); 2635 break; 2636 case offsetof(struct bpf_sockopt, optname): 2637 if (type == BPF_WRITE) 2638 *insn++ = CG_SOCKOPT_WRITE_FIELD(optname); 2639 else 2640 *insn++ = CG_SOCKOPT_READ_FIELD(optname); 2641 break; 2642 case offsetof(struct bpf_sockopt, optlen): 2643 if (type == BPF_WRITE) 2644 *insn++ = CG_SOCKOPT_WRITE_FIELD(optlen); 2645 else 2646 *insn++ = CG_SOCKOPT_READ_FIELD(optlen); 2647 break; 2648 case offsetof(struct bpf_sockopt, retval): 2649 BUILD_BUG_ON(offsetof(struct bpf_cg_run_ctx, run_ctx) != 0); 2650 2651 if (type == BPF_WRITE) { 2652 int treg = BPF_REG_9; 2653 2654 if (si->src_reg == treg || si->dst_reg == treg) 2655 --treg; 2656 if (si->src_reg == treg || si->dst_reg == treg) 2657 --treg; 2658 *insn++ = BPF_STX_MEM(BPF_DW, si->dst_reg, treg, 2659 offsetof(struct bpf_sockopt_kern, tmp_reg)); 2660 *insn++ = BPF_LDX_MEM(BPF_FIELD_SIZEOF(struct bpf_sockopt_kern, current_task), 2661 treg, si->dst_reg, 2662 offsetof(struct bpf_sockopt_kern, current_task)); 2663 *insn++ = BPF_LDX_MEM(BPF_FIELD_SIZEOF(struct task_struct, bpf_ctx), 2664 treg, treg, 2665 offsetof(struct task_struct, bpf_ctx)); 2666 *insn++ = BPF_RAW_INSN(BPF_CLASS(si->code) | BPF_MEM | 2667 BPF_FIELD_SIZEOF(struct bpf_cg_run_ctx, retval), 2668 treg, si->src_reg, 2669 offsetof(struct bpf_cg_run_ctx, retval), 2670 si->imm); 2671 *insn++ = BPF_LDX_MEM(BPF_DW, treg, si->dst_reg, 2672 offsetof(struct bpf_sockopt_kern, tmp_reg)); 2673 } else { 2674 *insn++ = BPF_LDX_MEM(BPF_FIELD_SIZEOF(struct bpf_sockopt_kern, current_task), 2675 si->dst_reg, si->src_reg, 2676 offsetof(struct bpf_sockopt_kern, current_task)); 2677 *insn++ = BPF_LDX_MEM(BPF_FIELD_SIZEOF(struct task_struct, bpf_ctx), 2678 si->dst_reg, si->dst_reg, 2679 offsetof(struct task_struct, bpf_ctx)); 2680 *insn++ = BPF_LDX_MEM(BPF_FIELD_SIZEOF(struct bpf_cg_run_ctx, retval), 2681 si->dst_reg, si->dst_reg, 2682 offsetof(struct bpf_cg_run_ctx, retval)); 2683 } 2684 break; 2685 case offsetof(struct bpf_sockopt, optval): 2686 *insn++ = CG_SOCKOPT_READ_FIELD(optval); 2687 break; 2688 case offsetof(struct bpf_sockopt, optval_end): 2689 *insn++ = CG_SOCKOPT_READ_FIELD(optval_end); 2690 break; 2691 } 2692 2693 return insn - insn_buf; 2694} 2695 2696static int cg_sockopt_get_prologue(struct bpf_insn *insn_buf, 2697 bool direct_write, 2698 const struct bpf_prog *prog) 2699{ 2700 /* Nothing to do for sockopt argument. The data is kzalloc'ated. 2701 */ 2702 return 0; 2703} 2704 2705const struct bpf_verifier_ops cg_sockopt_verifier_ops = { 2706 .get_func_proto = cg_sockopt_func_proto, 2707 .is_valid_access = cg_sockopt_is_valid_access, 2708 .convert_ctx_access = cg_sockopt_convert_ctx_access, 2709 .gen_prologue = cg_sockopt_get_prologue, 2710}; 2711 2712const struct bpf_prog_ops cg_sockopt_prog_ops = { 2713}; 2714 2715/* Common helpers for cgroup hooks. */ 2716const struct bpf_func_proto * 2717cgroup_common_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog) 2718{ 2719 switch (func_id) { 2720 case BPF_FUNC_get_local_storage: 2721 return &bpf_get_local_storage_proto; 2722 case BPF_FUNC_get_retval: 2723 switch (prog->expected_attach_type) { 2724 case BPF_CGROUP_INET_INGRESS: 2725 case BPF_CGROUP_INET_EGRESS: 2726 case BPF_CGROUP_SOCK_OPS: 2727 case BPF_CGROUP_UDP4_RECVMSG: 2728 case BPF_CGROUP_UDP6_RECVMSG: 2729 case BPF_CGROUP_UNIX_RECVMSG: 2730 case BPF_CGROUP_INET4_GETPEERNAME: 2731 case BPF_CGROUP_INET6_GETPEERNAME: 2732 case BPF_CGROUP_UNIX_GETPEERNAME: 2733 case BPF_CGROUP_INET4_GETSOCKNAME: 2734 case BPF_CGROUP_INET6_GETSOCKNAME: 2735 case BPF_CGROUP_UNIX_GETSOCKNAME: 2736 return NULL; 2737 default: 2738 return &bpf_get_retval_proto; 2739 } 2740 case BPF_FUNC_set_retval: 2741 switch (prog->expected_attach_type) { 2742 case BPF_CGROUP_INET_INGRESS: 2743 case BPF_CGROUP_INET_EGRESS: 2744 case BPF_CGROUP_SOCK_OPS: 2745 case BPF_CGROUP_UDP4_RECVMSG: 2746 case BPF_CGROUP_UDP6_RECVMSG: 2747 case BPF_CGROUP_UNIX_RECVMSG: 2748 case BPF_CGROUP_INET4_GETPEERNAME: 2749 case BPF_CGROUP_INET6_GETPEERNAME: 2750 case BPF_CGROUP_UNIX_GETPEERNAME: 2751 case BPF_CGROUP_INET4_GETSOCKNAME: 2752 case BPF_CGROUP_INET6_GETSOCKNAME: 2753 case BPF_CGROUP_UNIX_GETSOCKNAME: 2754 return NULL; 2755 default: 2756 return &bpf_set_retval_proto; 2757 } 2758 default: 2759 return NULL; 2760 } 2761}
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