cipso_ipv4.c

   1// SPDX-License-Identifier: GPL-2.0-or-later
   2/*
   3 * CIPSO - Commercial IP Security Option
   4 *
   5 * This is an implementation of the CIPSO 2.2 protocol as specified in
   6 * draft-ietf-cipso-ipsecurity-01.txt with additional tag types as found in
   7 * FIPS-188.  While CIPSO never became a full IETF RFC standard many vendors
   8 * have chosen to adopt the protocol and over the years it has become a
   9 * de-facto standard for labeled networking.
  10 *
  11 * The CIPSO draft specification can be found in the kernel's Documentation
  12 * directory as well as the following URL:
  13 *   https://tools.ietf.org/id/draft-ietf-cipso-ipsecurity-01.txt
  14 * The FIPS-188 specification can be found at the following URL:
  15 *   https://www.itl.nist.gov/fipspubs/fip188.htm
  16 *
  17 * Author: Paul Moore <paul.moore@hp.com>
  18 */
  19
  20/*
  21 * (c) Copyright Hewlett-Packard Development Company, L.P., 2006, 2008
  22 */
  23
  24#include <linux/init.h>
  25#include <linux/types.h>
  26#include <linux/rcupdate.h>
  27#include <linux/list.h>
  28#include <linux/spinlock.h>
  29#include <linux/string.h>
  30#include <linux/jhash.h>
  31#include <linux/audit.h>
  32#include <linux/slab.h>
  33#include <net/ip.h>
  34#include <net/icmp.h>
  35#include <net/tcp.h>
  36#include <net/netlabel.h>
  37#include <net/cipso_ipv4.h>
  38#include <linux/atomic.h>
  39#include <linux/bug.h>
  40#include <linux/unaligned.h>
  41
  42/* List of available DOI definitions */
  43/* XXX - This currently assumes a minimal number of different DOIs in use,
  44 * if in practice there are a lot of different DOIs this list should
  45 * probably be turned into a hash table or something similar so we
  46 * can do quick lookups. */
  47static DEFINE_SPINLOCK(cipso_v4_doi_list_lock);
  48static LIST_HEAD(cipso_v4_doi_list);
  49
  50/* Label mapping cache */
  51int cipso_v4_cache_enabled = 1;
  52int cipso_v4_cache_bucketsize = 10;
  53#define CIPSO_V4_CACHE_BUCKETBITS     7
  54#define CIPSO_V4_CACHE_BUCKETS        (1 << CIPSO_V4_CACHE_BUCKETBITS)
  55#define CIPSO_V4_CACHE_REORDERLIMIT   10
  56struct cipso_v4_map_cache_bkt {
  57	spinlock_t lock;
  58	u32 size;
  59	struct list_head list;
  60};
  61
  62struct cipso_v4_map_cache_entry {
  63	u32 hash;
  64	unsigned char *key;
  65	size_t key_len;
  66
  67	struct netlbl_lsm_cache *lsm_data;
  68
  69	u32 activity;
  70	struct list_head list;
  71};
  72
  73static struct cipso_v4_map_cache_bkt *cipso_v4_cache;
  74
  75/* Restricted bitmap (tag #1) flags */
  76int cipso_v4_rbm_optfmt;
  77int cipso_v4_rbm_strictvalid = 1;
  78
  79/*
  80 * Protocol Constants
  81 */
  82
  83/* Maximum size of the CIPSO IP option, derived from the fact that the maximum
  84 * IPv4 header size is 60 bytes and the base IPv4 header is 20 bytes long. */
  85#define CIPSO_V4_OPT_LEN_MAX          40
  86
  87/* Length of the base CIPSO option, this includes the option type (1 byte), the
  88 * option length (1 byte), and the DOI (4 bytes). */
  89#define CIPSO_V4_HDR_LEN              6
  90
  91/* Base length of the restrictive category bitmap tag (tag #1). */
  92#define CIPSO_V4_TAG_RBM_BLEN         4
  93
  94/* Base length of the enumerated category tag (tag #2). */
  95#define CIPSO_V4_TAG_ENUM_BLEN        4
  96
  97/* Base length of the ranged categories bitmap tag (tag #5). */
  98#define CIPSO_V4_TAG_RNG_BLEN         4
  99/* The maximum number of category ranges permitted in the ranged category tag
 100 * (tag #5).  You may note that the IETF draft states that the maximum number
 101 * of category ranges is 7, but if the low end of the last category range is
 102 * zero then it is possible to fit 8 category ranges because the zero should
 103 * be omitted. */
 104#define CIPSO_V4_TAG_RNG_CAT_MAX      8
 105
 106/* Base length of the local tag (non-standard tag).
 107 *  Tag definition (may change between kernel versions)
 108 *
 109 * 0          8          16         24         32
 110 * +----------+----------+----------+----------+
 111 * | 10000000 | 00000110 | 32-bit secid value  |
 112 * +----------+----------+----------+----------+
 113 * | in (host byte order)|
 114 * +----------+----------+
 115 *
 116 */
 117#define CIPSO_V4_TAG_LOC_BLEN         6
 118
 119/*
 120 * Helper Functions
 121 */
 122
 123/**
 124 * cipso_v4_cache_entry_free - Frees a cache entry
 125 * @entry: the entry to free
 126 *
 127 * Description:
 128 * This function frees the memory associated with a cache entry including the
 129 * LSM cache data if there are no longer any users, i.e. reference count == 0.
 130 *
 131 */
 132static void cipso_v4_cache_entry_free(struct cipso_v4_map_cache_entry *entry)
 133{
 134	if (entry->lsm_data)
 135		netlbl_secattr_cache_free(entry->lsm_data);
 136	kfree(entry->key);
 137	kfree(entry);
 138}
 139
 140/**
 141 * cipso_v4_map_cache_hash - Hashing function for the CIPSO cache
 142 * @key: the hash key
 143 * @key_len: the length of the key in bytes
 144 *
 145 * Description:
 146 * The CIPSO tag hashing function.  Returns a 32-bit hash value.
 147 *
 148 */
 149static u32 cipso_v4_map_cache_hash(const unsigned char *key, u32 key_len)
 150{
 151	return jhash(key, key_len, 0);
 152}
 153
 154/*
 155 * Label Mapping Cache Functions
 156 */
 157
 158/**
 159 * cipso_v4_cache_init - Initialize the CIPSO cache
 160 *
 161 * Description:
 162 * Initializes the CIPSO label mapping cache, this function should be called
 163 * before any of the other functions defined in this file.  Returns zero on
 164 * success, negative values on error.
 165 *
 166 */
 167static int __init cipso_v4_cache_init(void)
 168{
 169	u32 iter;
 170
 171	cipso_v4_cache = kcalloc(CIPSO_V4_CACHE_BUCKETS,
 172				 sizeof(struct cipso_v4_map_cache_bkt),
 173				 GFP_KERNEL);
 174	if (!cipso_v4_cache)
 175		return -ENOMEM;
 176
 177	for (iter = 0; iter < CIPSO_V4_CACHE_BUCKETS; iter++) {
 178		spin_lock_init(&cipso_v4_cache[iter].lock);
 179		cipso_v4_cache[iter].size = 0;
 180		INIT_LIST_HEAD(&cipso_v4_cache[iter].list);
 181	}
 182
 183	return 0;
 184}
 185
 186/**
 187 * cipso_v4_cache_invalidate - Invalidates the current CIPSO cache
 188 *
 189 * Description:
 190 * Invalidates and frees any entries in the CIPSO cache.
 191 *
 192 */
 193void cipso_v4_cache_invalidate(void)
 194{
 195	struct cipso_v4_map_cache_entry *entry, *tmp_entry;
 196	u32 iter;
 197
 198	for (iter = 0; iter < CIPSO_V4_CACHE_BUCKETS; iter++) {
 199		spin_lock_bh(&cipso_v4_cache[iter].lock);
 200		list_for_each_entry_safe(entry,
 201					 tmp_entry,
 202					 &cipso_v4_cache[iter].list, list) {
 203			list_del(&entry->list);
 204			cipso_v4_cache_entry_free(entry);
 205		}
 206		cipso_v4_cache[iter].size = 0;
 207		spin_unlock_bh(&cipso_v4_cache[iter].lock);
 208	}
 209}
 210
 211/**
 212 * cipso_v4_cache_check - Check the CIPSO cache for a label mapping
 213 * @key: the buffer to check
 214 * @key_len: buffer length in bytes
 215 * @secattr: the security attribute struct to use
 216 *
 217 * Description:
 218 * This function checks the cache to see if a label mapping already exists for
 219 * the given key.  If there is a match then the cache is adjusted and the
 220 * @secattr struct is populated with the correct LSM security attributes.  The
 221 * cache is adjusted in the following manner if the entry is not already the
 222 * first in the cache bucket:
 223 *
 224 *  1. The cache entry's activity counter is incremented
 225 *  2. The previous (higher ranking) entry's activity counter is decremented
 226 *  3. If the difference between the two activity counters is geater than
 227 *     CIPSO_V4_CACHE_REORDERLIMIT the two entries are swapped
 228 *
 229 * Returns zero on success, -ENOENT for a cache miss, and other negative values
 230 * on error.
 231 *
 232 */
 233static int cipso_v4_cache_check(const unsigned char *key,
 234				u32 key_len,
 235				struct netlbl_lsm_secattr *secattr)
 236{
 237	u32 bkt;
 238	struct cipso_v4_map_cache_entry *entry;
 239	struct cipso_v4_map_cache_entry *prev_entry = NULL;
 240	u32 hash;
 241
 242	if (!READ_ONCE(cipso_v4_cache_enabled))
 243		return -ENOENT;
 244
 245	hash = cipso_v4_map_cache_hash(key, key_len);
 246	bkt = hash & (CIPSO_V4_CACHE_BUCKETS - 1);
 247	spin_lock_bh(&cipso_v4_cache[bkt].lock);
 248	list_for_each_entry(entry, &cipso_v4_cache[bkt].list, list) {
 249		if (entry->hash == hash &&
 250		    entry->key_len == key_len &&
 251		    memcmp(entry->key, key, key_len) == 0) {
 252			entry->activity += 1;
 253			refcount_inc(&entry->lsm_data->refcount);
 254			secattr->cache = entry->lsm_data;
 255			secattr->flags |= NETLBL_SECATTR_CACHE;
 256			secattr->type = NETLBL_NLTYPE_CIPSOV4;
 257			if (!prev_entry) {
 258				spin_unlock_bh(&cipso_v4_cache[bkt].lock);
 259				return 0;
 260			}
 261
 262			if (prev_entry->activity > 0)
 263				prev_entry->activity -= 1;
 264			if (entry->activity > prev_entry->activity &&
 265			    entry->activity - prev_entry->activity >
 266			    CIPSO_V4_CACHE_REORDERLIMIT) {
 267				__list_del(entry->list.prev, entry->list.next);
 268				__list_add(&entry->list,
 269					   prev_entry->list.prev,
 270					   &prev_entry->list);
 271			}
 272
 273			spin_unlock_bh(&cipso_v4_cache[bkt].lock);
 274			return 0;
 275		}
 276		prev_entry = entry;
 277	}
 278	spin_unlock_bh(&cipso_v4_cache[bkt].lock);
 279
 280	return -ENOENT;
 281}
 282
 283/**
 284 * cipso_v4_cache_add - Add an entry to the CIPSO cache
 285 * @cipso_ptr: pointer to CIPSO IP option
 286 * @secattr: the packet's security attributes
 287 *
 288 * Description:
 289 * Add a new entry into the CIPSO label mapping cache.  Add the new entry to
 290 * head of the cache bucket's list, if the cache bucket is out of room remove
 291 * the last entry in the list first.  It is important to note that there is
 292 * currently no checking for duplicate keys.  Returns zero on success,
 293 * negative values on failure.
 294 *
 295 */
 296int cipso_v4_cache_add(const unsigned char *cipso_ptr,
 297		       const struct netlbl_lsm_secattr *secattr)
 298{
 299	int bkt_size = READ_ONCE(cipso_v4_cache_bucketsize);
 300	int ret_val = -EPERM;
 301	u32 bkt;
 302	struct cipso_v4_map_cache_entry *entry = NULL;
 303	struct cipso_v4_map_cache_entry *old_entry = NULL;
 304	u32 cipso_ptr_len;
 305
 306	if (!READ_ONCE(cipso_v4_cache_enabled) || bkt_size <= 0)
 307		return 0;
 308
 309	cipso_ptr_len = cipso_ptr[1];
 310
 311	entry = kzalloc(sizeof(*entry), GFP_ATOMIC);
 312	if (!entry)
 313		return -ENOMEM;
 314	entry->key = kmemdup(cipso_ptr, cipso_ptr_len, GFP_ATOMIC);
 315	if (!entry->key) {
 316		ret_val = -ENOMEM;
 317		goto cache_add_failure;
 318	}
 319	entry->key_len = cipso_ptr_len;
 320	entry->hash = cipso_v4_map_cache_hash(cipso_ptr, cipso_ptr_len);
 321	refcount_inc(&secattr->cache->refcount);
 322	entry->lsm_data = secattr->cache;
 323
 324	bkt = entry->hash & (CIPSO_V4_CACHE_BUCKETS - 1);
 325	spin_lock_bh(&cipso_v4_cache[bkt].lock);
 326	if (cipso_v4_cache[bkt].size < bkt_size) {
 327		list_add(&entry->list, &cipso_v4_cache[bkt].list);
 328		cipso_v4_cache[bkt].size += 1;
 329	} else {
 330		old_entry = list_entry(cipso_v4_cache[bkt].list.prev,
 331				       struct cipso_v4_map_cache_entry, list);
 332		list_del(&old_entry->list);
 333		list_add(&entry->list, &cipso_v4_cache[bkt].list);
 334		cipso_v4_cache_entry_free(old_entry);
 335	}
 336	spin_unlock_bh(&cipso_v4_cache[bkt].lock);
 337
 338	return 0;
 339
 340cache_add_failure:
 341	if (entry)
 342		cipso_v4_cache_entry_free(entry);
 343	return ret_val;
 344}
 345
 346/*
 347 * DOI List Functions
 348 */
 349
 350/**
 351 * cipso_v4_doi_search - Searches for a DOI definition
 352 * @doi: the DOI to search for
 353 *
 354 * Description:
 355 * Search the DOI definition list for a DOI definition with a DOI value that
 356 * matches @doi.  The caller is responsible for calling rcu_read_[un]lock().
 357 * Returns a pointer to the DOI definition on success and NULL on failure.
 358 */
 359static struct cipso_v4_doi *cipso_v4_doi_search(u32 doi)
 360{
 361	struct cipso_v4_doi *iter;
 362
 363	list_for_each_entry_rcu(iter, &cipso_v4_doi_list, list)
 364		if (iter->doi == doi && refcount_read(&iter->refcount))
 365			return iter;
 366	return NULL;
 367}
 368
 369/**
 370 * cipso_v4_doi_add - Add a new DOI to the CIPSO protocol engine
 371 * @doi_def: the DOI structure
 372 * @audit_info: NetLabel audit information
 373 *
 374 * Description:
 375 * The caller defines a new DOI for use by the CIPSO engine and calls this
 376 * function to add it to the list of acceptable domains.  The caller must
 377 * ensure that the mapping table specified in @doi_def->map meets all of the
 378 * requirements of the mapping type (see cipso_ipv4.h for details).  Returns
 379 * zero on success and non-zero on failure.
 380 *
 381 */
 382int cipso_v4_doi_add(struct cipso_v4_doi *doi_def,
 383		     struct netlbl_audit *audit_info)
 384{
 385	int ret_val = -EINVAL;
 386	u32 iter;
 387	u32 doi;
 388	u32 doi_type;
 389	struct audit_buffer *audit_buf;
 390
 391	doi = doi_def->doi;
 392	doi_type = doi_def->type;
 393
 394	if (doi_def->doi == CIPSO_V4_DOI_UNKNOWN)
 395		goto doi_add_return;
 396	for (iter = 0; iter < CIPSO_V4_TAG_MAXCNT; iter++) {
 397		switch (doi_def->tags[iter]) {
 398		case CIPSO_V4_TAG_RBITMAP:
 399			break;
 400		case CIPSO_V4_TAG_RANGE:
 401		case CIPSO_V4_TAG_ENUM:
 402			if (doi_def->type != CIPSO_V4_MAP_PASS)
 403				goto doi_add_return;
 404			break;
 405		case CIPSO_V4_TAG_LOCAL:
 406			if (doi_def->type != CIPSO_V4_MAP_LOCAL)
 407				goto doi_add_return;
 408			break;
 409		case CIPSO_V4_TAG_INVALID:
 410			if (iter == 0)
 411				goto doi_add_return;
 412			break;
 413		default:
 414			goto doi_add_return;
 415		}
 416	}
 417
 418	refcount_set(&doi_def->refcount, 1);
 419
 420	spin_lock(&cipso_v4_doi_list_lock);
 421	if (cipso_v4_doi_search(doi_def->doi)) {
 422		spin_unlock(&cipso_v4_doi_list_lock);
 423		ret_val = -EEXIST;
 424		goto doi_add_return;
 425	}
 426	list_add_tail_rcu(&doi_def->list, &cipso_v4_doi_list);
 427	spin_unlock(&cipso_v4_doi_list_lock);
 428	ret_val = 0;
 429
 430doi_add_return:
 431	audit_buf = netlbl_audit_start(AUDIT_MAC_CIPSOV4_ADD, audit_info);
 432	if (audit_buf) {
 433		const char *type_str;
 434		switch (doi_type) {
 435		case CIPSO_V4_MAP_TRANS:
 436			type_str = "trans";
 437			break;
 438		case CIPSO_V4_MAP_PASS:
 439			type_str = "pass";
 440			break;
 441		case CIPSO_V4_MAP_LOCAL:
 442			type_str = "local";
 443			break;
 444		default:
 445			type_str = "(unknown)";
 446		}
 447		audit_log_format(audit_buf,
 448				 " cipso_doi=%u cipso_type=%s res=%u",
 449				 doi, type_str, ret_val == 0 ? 1 : 0);
 450		audit_log_end(audit_buf);
 451	}
 452
 453	return ret_val;
 454}
 455
 456/**
 457 * cipso_v4_doi_free - Frees a DOI definition
 458 * @doi_def: the DOI definition
 459 *
 460 * Description:
 461 * This function frees all of the memory associated with a DOI definition.
 462 *
 463 */
 464void cipso_v4_doi_free(struct cipso_v4_doi *doi_def)
 465{
 466	if (!doi_def)
 467		return;
 468
 469	switch (doi_def->type) {
 470	case CIPSO_V4_MAP_TRANS:
 471		kfree(doi_def->map.std->lvl.cipso);
 472		kfree(doi_def->map.std->lvl.local);
 473		kfree(doi_def->map.std->cat.cipso);
 474		kfree(doi_def->map.std->cat.local);
 475		kfree(doi_def->map.std);
 476		break;
 477	}
 478	kfree(doi_def);
 479}
 480
 481/**
 482 * cipso_v4_doi_free_rcu - Frees a DOI definition via the RCU pointer
 483 * @entry: the entry's RCU field
 484 *
 485 * Description:
 486 * This function is designed to be used as a callback to the call_rcu()
 487 * function so that the memory allocated to the DOI definition can be released
 488 * safely.
 489 *
 490 */
 491static void cipso_v4_doi_free_rcu(struct rcu_head *entry)
 492{
 493	struct cipso_v4_doi *doi_def;
 494
 495	doi_def = container_of(entry, struct cipso_v4_doi, rcu);
 496	cipso_v4_doi_free(doi_def);
 497}
 498
 499/**
 500 * cipso_v4_doi_remove - Remove an existing DOI from the CIPSO protocol engine
 501 * @doi: the DOI value
 502 * @audit_info: NetLabel audit information
 503 *
 504 * Description:
 505 * Removes a DOI definition from the CIPSO engine.  The NetLabel routines will
 506 * be called to release their own LSM domain mappings as well as our own
 507 * domain list.  Returns zero on success and negative values on failure.
 508 *
 509 */
 510int cipso_v4_doi_remove(u32 doi, struct netlbl_audit *audit_info)
 511{
 512	int ret_val;
 513	struct cipso_v4_doi *doi_def;
 514	struct audit_buffer *audit_buf;
 515
 516	spin_lock(&cipso_v4_doi_list_lock);
 517	doi_def = cipso_v4_doi_search(doi);
 518	if (!doi_def) {
 519		spin_unlock(&cipso_v4_doi_list_lock);
 520		ret_val = -ENOENT;
 521		goto doi_remove_return;
 522	}
 523	list_del_rcu(&doi_def->list);
 524	spin_unlock(&cipso_v4_doi_list_lock);
 525
 526	cipso_v4_doi_putdef(doi_def);
 527	ret_val = 0;
 528
 529doi_remove_return:
 530	audit_buf = netlbl_audit_start(AUDIT_MAC_CIPSOV4_DEL, audit_info);
 531	if (audit_buf) {
 532		audit_log_format(audit_buf,
 533				 " cipso_doi=%u res=%u",
 534				 doi, ret_val == 0 ? 1 : 0);
 535		audit_log_end(audit_buf);
 536	}
 537
 538	return ret_val;
 539}
 540
 541/**
 542 * cipso_v4_doi_getdef - Returns a reference to a valid DOI definition
 543 * @doi: the DOI value
 544 *
 545 * Description:
 546 * Searches for a valid DOI definition and if one is found it is returned to
 547 * the caller.  Otherwise NULL is returned.  The caller must ensure that
 548 * rcu_read_lock() is held while accessing the returned definition and the DOI
 549 * definition reference count is decremented when the caller is done.
 550 *
 551 */
 552struct cipso_v4_doi *cipso_v4_doi_getdef(u32 doi)
 553{
 554	struct cipso_v4_doi *doi_def;
 555
 556	rcu_read_lock();
 557	doi_def = cipso_v4_doi_search(doi);
 558	if (!doi_def)
 559		goto doi_getdef_return;
 560	if (!refcount_inc_not_zero(&doi_def->refcount))
 561		doi_def = NULL;
 562
 563doi_getdef_return:
 564	rcu_read_unlock();
 565	return doi_def;
 566}
 567
 568/**
 569 * cipso_v4_doi_putdef - Releases a reference for the given DOI definition
 570 * @doi_def: the DOI definition
 571 *
 572 * Description:
 573 * Releases a DOI definition reference obtained from cipso_v4_doi_getdef().
 574 *
 575 */
 576void cipso_v4_doi_putdef(struct cipso_v4_doi *doi_def)
 577{
 578	if (!doi_def)
 579		return;
 580
 581	if (!refcount_dec_and_test(&doi_def->refcount))
 582		return;
 583
 584	cipso_v4_cache_invalidate();
 585	call_rcu(&doi_def->rcu, cipso_v4_doi_free_rcu);
 586}
 587
 588/**
 589 * cipso_v4_doi_walk - Iterate through the DOI definitions
 590 * @skip_cnt: skip past this number of DOI definitions, updated
 591 * @callback: callback for each DOI definition
 592 * @cb_arg: argument for the callback function
 593 *
 594 * Description:
 595 * Iterate over the DOI definition list, skipping the first @skip_cnt entries.
 596 * For each entry call @callback, if @callback returns a negative value stop
 597 * 'walking' through the list and return.  Updates the value in @skip_cnt upon
 598 * return.  Returns zero on success, negative values on failure.
 599 *
 600 */
 601int cipso_v4_doi_walk(u32 *skip_cnt,
 602		     int (*callback) (struct cipso_v4_doi *doi_def, void *arg),
 603		     void *cb_arg)
 604{
 605	int ret_val = -ENOENT;
 606	u32 doi_cnt = 0;
 607	struct cipso_v4_doi *iter_doi;
 608
 609	rcu_read_lock();
 610	list_for_each_entry_rcu(iter_doi, &cipso_v4_doi_list, list)
 611		if (refcount_read(&iter_doi->refcount) > 0) {
 612			if (doi_cnt++ < *skip_cnt)
 613				continue;
 614			ret_val = callback(iter_doi, cb_arg);
 615			if (ret_val < 0) {
 616				doi_cnt--;
 617				goto doi_walk_return;
 618			}
 619		}
 620
 621doi_walk_return:
 622	rcu_read_unlock();
 623	*skip_cnt = doi_cnt;
 624	return ret_val;
 625}
 626
 627/*
 628 * Label Mapping Functions
 629 */
 630
 631/**
 632 * cipso_v4_map_lvl_valid - Checks to see if the given level is understood
 633 * @doi_def: the DOI definition
 634 * @level: the level to check
 635 *
 636 * Description:
 637 * Checks the given level against the given DOI definition and returns a
 638 * negative value if the level does not have a valid mapping and a zero value
 639 * if the level is defined by the DOI.
 640 *
 641 */
 642static int cipso_v4_map_lvl_valid(const struct cipso_v4_doi *doi_def, u8 level)
 643{
 644	switch (doi_def->type) {
 645	case CIPSO_V4_MAP_PASS:
 646		return 0;
 647	case CIPSO_V4_MAP_TRANS:
 648		if ((level < doi_def->map.std->lvl.cipso_size) &&
 649		    (doi_def->map.std->lvl.cipso[level] < CIPSO_V4_INV_LVL))
 650			return 0;
 651		break;
 652	}
 653
 654	return -EFAULT;
 655}
 656
 657/**
 658 * cipso_v4_map_lvl_hton - Perform a level mapping from the host to the network
 659 * @doi_def: the DOI definition
 660 * @host_lvl: the host MLS level
 661 * @net_lvl: the network/CIPSO MLS level
 662 *
 663 * Description:
 664 * Perform a label mapping to translate a local MLS level to the correct
 665 * CIPSO level using the given DOI definition.  Returns zero on success,
 666 * negative values otherwise.
 667 *
 668 */
 669static int cipso_v4_map_lvl_hton(const struct cipso_v4_doi *doi_def,
 670				 u32 host_lvl,
 671				 u32 *net_lvl)
 672{
 673	switch (doi_def->type) {
 674	case CIPSO_V4_MAP_PASS:
 675		*net_lvl = host_lvl;
 676		return 0;
 677	case CIPSO_V4_MAP_TRANS:
 678		if (host_lvl < doi_def->map.std->lvl.local_size &&
 679		    doi_def->map.std->lvl.local[host_lvl] < CIPSO_V4_INV_LVL) {
 680			*net_lvl = doi_def->map.std->lvl.local[host_lvl];
 681			return 0;
 682		}
 683		return -EPERM;
 684	}
 685
 686	return -EINVAL;
 687}
 688
 689/**
 690 * cipso_v4_map_lvl_ntoh - Perform a level mapping from the network to the host
 691 * @doi_def: the DOI definition
 692 * @net_lvl: the network/CIPSO MLS level
 693 * @host_lvl: the host MLS level
 694 *
 695 * Description:
 696 * Perform a label mapping to translate a CIPSO level to the correct local MLS
 697 * level using the given DOI definition.  Returns zero on success, negative
 698 * values otherwise.
 699 *
 700 */
 701static int cipso_v4_map_lvl_ntoh(const struct cipso_v4_doi *doi_def,
 702				 u32 net_lvl,
 703				 u32 *host_lvl)
 704{
 705	struct cipso_v4_std_map_tbl *map_tbl;
 706
 707	switch (doi_def->type) {
 708	case CIPSO_V4_MAP_PASS:
 709		*host_lvl = net_lvl;
 710		return 0;
 711	case CIPSO_V4_MAP_TRANS:
 712		map_tbl = doi_def->map.std;
 713		if (net_lvl < map_tbl->lvl.cipso_size &&
 714		    map_tbl->lvl.cipso[net_lvl] < CIPSO_V4_INV_LVL) {
 715			*host_lvl = doi_def->map.std->lvl.cipso[net_lvl];
 716			return 0;
 717		}
 718		return -EPERM;
 719	}
 720
 721	return -EINVAL;
 722}
 723
 724/**
 725 * cipso_v4_map_cat_rbm_valid - Checks to see if the category bitmap is valid
 726 * @doi_def: the DOI definition
 727 * @bitmap: category bitmap
 728 * @bitmap_len: bitmap length in bytes
 729 *
 730 * Description:
 731 * Checks the given category bitmap against the given DOI definition and
 732 * returns a negative value if any of the categories in the bitmap do not have
 733 * a valid mapping and a zero value if all of the categories are valid.
 734 *
 735 */
 736static int cipso_v4_map_cat_rbm_valid(const struct cipso_v4_doi *doi_def,
 737				      const unsigned char *bitmap,
 738				      u32 bitmap_len)
 739{
 740	int cat = -1;
 741	u32 bitmap_len_bits = bitmap_len * 8;
 742	u32 cipso_cat_size;
 743	u32 *cipso_array;
 744
 745	switch (doi_def->type) {
 746	case CIPSO_V4_MAP_PASS:
 747		return 0;
 748	case CIPSO_V4_MAP_TRANS:
 749		cipso_cat_size = doi_def->map.std->cat.cipso_size;
 750		cipso_array = doi_def->map.std->cat.cipso;
 751		for (;;) {
 752			cat = netlbl_bitmap_walk(bitmap,
 753						 bitmap_len_bits,
 754						 cat + 1,
 755						 1);
 756			if (cat < 0)
 757				break;
 758			if (cat >= cipso_cat_size ||
 759			    cipso_array[cat] >= CIPSO_V4_INV_CAT)
 760				return -EFAULT;
 761		}
 762
 763		if (cat == -1)
 764			return 0;
 765		break;
 766	}
 767
 768	return -EFAULT;
 769}
 770
 771/**
 772 * cipso_v4_map_cat_rbm_hton - Perform a category mapping from host to network
 773 * @doi_def: the DOI definition
 774 * @secattr: the security attributes
 775 * @net_cat: the zero'd out category bitmap in network/CIPSO format
 776 * @net_cat_len: the length of the CIPSO bitmap in bytes
 777 *
 778 * Description:
 779 * Perform a label mapping to translate a local MLS category bitmap to the
 780 * correct CIPSO bitmap using the given DOI definition.  Returns the minimum
 781 * size in bytes of the network bitmap on success, negative values otherwise.
 782 *
 783 */
 784static int cipso_v4_map_cat_rbm_hton(const struct cipso_v4_doi *doi_def,
 785				     const struct netlbl_lsm_secattr *secattr,
 786				     unsigned char *net_cat,
 787				     u32 net_cat_len)
 788{
 789	int host_spot = -1;
 790	u32 net_spot = CIPSO_V4_INV_CAT;
 791	u32 net_spot_max = 0;
 792	u32 net_clen_bits = net_cat_len * 8;
 793	u32 host_cat_size = 0;
 794	u32 *host_cat_array = NULL;
 795
 796	if (doi_def->type == CIPSO_V4_MAP_TRANS) {
 797		host_cat_size = doi_def->map.std->cat.local_size;
 798		host_cat_array = doi_def->map.std->cat.local;
 799	}
 800
 801	for (;;) {
 802		host_spot = netlbl_catmap_walk(secattr->attr.mls.cat,
 803					       host_spot + 1);
 804		if (host_spot < 0)
 805			break;
 806
 807		switch (doi_def->type) {
 808		case CIPSO_V4_MAP_PASS:
 809			net_spot = host_spot;
 810			break;
 811		case CIPSO_V4_MAP_TRANS:
 812			if (host_spot >= host_cat_size)
 813				return -EPERM;
 814			net_spot = host_cat_array[host_spot];
 815			if (net_spot >= CIPSO_V4_INV_CAT)
 816				return -EPERM;
 817			break;
 818		}
 819		if (net_spot >= net_clen_bits)
 820			return -ENOSPC;
 821		netlbl_bitmap_setbit(net_cat, net_spot, 1);
 822
 823		if (net_spot > net_spot_max)
 824			net_spot_max = net_spot;
 825	}
 826
 827	if (++net_spot_max % 8)
 828		return net_spot_max / 8 + 1;
 829	return net_spot_max / 8;
 830}
 831
 832/**
 833 * cipso_v4_map_cat_rbm_ntoh - Perform a category mapping from network to host
 834 * @doi_def: the DOI definition
 835 * @net_cat: the category bitmap in network/CIPSO format
 836 * @net_cat_len: the length of the CIPSO bitmap in bytes
 837 * @secattr: the security attributes
 838 *
 839 * Description:
 840 * Perform a label mapping to translate a CIPSO bitmap to the correct local
 841 * MLS category bitmap using the given DOI definition.  Returns zero on
 842 * success, negative values on failure.
 843 *
 844 */
 845static int cipso_v4_map_cat_rbm_ntoh(const struct cipso_v4_doi *doi_def,
 846				     const unsigned char *net_cat,
 847				     u32 net_cat_len,
 848				     struct netlbl_lsm_secattr *secattr)
 849{
 850	int ret_val;
 851	int net_spot = -1;
 852	u32 host_spot = CIPSO_V4_INV_CAT;
 853	u32 net_clen_bits = net_cat_len * 8;
 854	u32 net_cat_size = 0;
 855	u32 *net_cat_array = NULL;
 856
 857	if (doi_def->type == CIPSO_V4_MAP_TRANS) {
 858		net_cat_size = doi_def->map.std->cat.cipso_size;
 859		net_cat_array = doi_def->map.std->cat.cipso;
 860	}
 861
 862	for (;;) {
 863		net_spot = netlbl_bitmap_walk(net_cat,
 864					      net_clen_bits,
 865					      net_spot + 1,
 866					      1);
 867		if (net_spot < 0)
 868			return 0;
 869
 870		switch (doi_def->type) {
 871		case CIPSO_V4_MAP_PASS:
 872			host_spot = net_spot;
 873			break;
 874		case CIPSO_V4_MAP_TRANS:
 875			if (net_spot >= net_cat_size)
 876				return -EPERM;
 877			host_spot = net_cat_array[net_spot];
 878			if (host_spot >= CIPSO_V4_INV_CAT)
 879				return -EPERM;
 880			break;
 881		}
 882		ret_val = netlbl_catmap_setbit(&secattr->attr.mls.cat,
 883						       host_spot,
 884						       GFP_ATOMIC);
 885		if (ret_val != 0)
 886			return ret_val;
 887	}
 888
 889	return -EINVAL;
 890}
 891
 892/**
 893 * cipso_v4_map_cat_enum_valid - Checks to see if the categories are valid
 894 * @doi_def: the DOI definition
 895 * @enumcat: category list
 896 * @enumcat_len: length of the category list in bytes
 897 *
 898 * Description:
 899 * Checks the given categories against the given DOI definition and returns a
 900 * negative value if any of the categories do not have a valid mapping and a
 901 * zero value if all of the categories are valid.
 902 *
 903 */
 904static int cipso_v4_map_cat_enum_valid(const struct cipso_v4_doi *doi_def,
 905				       const unsigned char *enumcat,
 906				       u32 enumcat_len)
 907{
 908	u16 cat;
 909	int cat_prev = -1;
 910	u32 iter;
 911
 912	if (doi_def->type != CIPSO_V4_MAP_PASS || enumcat_len & 0x01)
 913		return -EFAULT;
 914
 915	for (iter = 0; iter < enumcat_len; iter += 2) {
 916		cat = get_unaligned_be16(&enumcat[iter]);
 917		if (cat <= cat_prev)
 918			return -EFAULT;
 919		cat_prev = cat;
 920	}
 921
 922	return 0;
 923}
 924
 925/**
 926 * cipso_v4_map_cat_enum_hton - Perform a category mapping from host to network
 927 * @doi_def: the DOI definition
 928 * @secattr: the security attributes
 929 * @net_cat: the zero'd out category list in network/CIPSO format
 930 * @net_cat_len: the length of the CIPSO category list in bytes
 931 *
 932 * Description:
 933 * Perform a label mapping to translate a local MLS category bitmap to the
 934 * correct CIPSO category list using the given DOI definition.   Returns the
 935 * size in bytes of the network category bitmap on success, negative values
 936 * otherwise.
 937 *
 938 */
 939static int cipso_v4_map_cat_enum_hton(const struct cipso_v4_doi *doi_def,
 940				      const struct netlbl_lsm_secattr *secattr,
 941				      unsigned char *net_cat,
 942				      u32 net_cat_len)
 943{
 944	int cat = -1;
 945	u32 cat_iter = 0;
 946
 947	for (;;) {
 948		cat = netlbl_catmap_walk(secattr->attr.mls.cat, cat + 1);
 949		if (cat < 0)
 950			break;
 951		if ((cat_iter + 2) > net_cat_len)
 952			return -ENOSPC;
 953
 954		*((__be16 *)&net_cat[cat_iter]) = htons(cat);
 955		cat_iter += 2;
 956	}
 957
 958	return cat_iter;
 959}
 960
 961/**
 962 * cipso_v4_map_cat_enum_ntoh - Perform a category mapping from network to host
 963 * @doi_def: the DOI definition
 964 * @net_cat: the category list in network/CIPSO format
 965 * @net_cat_len: the length of the CIPSO bitmap in bytes
 966 * @secattr: the security attributes
 967 *
 968 * Description:
 969 * Perform a label mapping to translate a CIPSO category list to the correct
 970 * local MLS category bitmap using the given DOI definition.  Returns zero on
 971 * success, negative values on failure.
 972 *
 973 */
 974static int cipso_v4_map_cat_enum_ntoh(const struct cipso_v4_doi *doi_def,
 975				      const unsigned char *net_cat,
 976				      u32 net_cat_len,
 977				      struct netlbl_lsm_secattr *secattr)
 978{
 979	int ret_val;
 980	u32 iter;
 981
 982	for (iter = 0; iter < net_cat_len; iter += 2) {
 983		ret_val = netlbl_catmap_setbit(&secattr->attr.mls.cat,
 984					     get_unaligned_be16(&net_cat[iter]),
 985					     GFP_ATOMIC);
 986		if (ret_val != 0)
 987			return ret_val;
 988	}
 989
 990	return 0;
 991}
 992
 993/**
 994 * cipso_v4_map_cat_rng_valid - Checks to see if the categories are valid
 995 * @doi_def: the DOI definition
 996 * @rngcat: category list
 997 * @rngcat_len: length of the category list in bytes
 998 *
 999 * Description:
1000 * Checks the given categories against the given DOI definition and returns a
1001 * negative value if any of the categories do not have a valid mapping and a
1002 * zero value if all of the categories are valid.
1003 *
1004 */
1005static int cipso_v4_map_cat_rng_valid(const struct cipso_v4_doi *doi_def,
1006				      const unsigned char *rngcat,
1007				      u32 rngcat_len)
1008{
1009	u16 cat_high;
1010	u16 cat_low;
1011	u32 cat_prev = CIPSO_V4_MAX_REM_CATS + 1;
1012	u32 iter;
1013
1014	if (doi_def->type != CIPSO_V4_MAP_PASS || rngcat_len & 0x01)
1015		return -EFAULT;
1016
1017	for (iter = 0; iter < rngcat_len; iter += 4) {
1018		cat_high = get_unaligned_be16(&rngcat[iter]);
1019		if ((iter + 4) <= rngcat_len)
1020			cat_low = get_unaligned_be16(&rngcat[iter + 2]);
1021		else
1022			cat_low = 0;
1023
1024		if (cat_high > cat_prev)
1025			return -EFAULT;
1026
1027		cat_prev = cat_low;
1028	}
1029
1030	return 0;
1031}
1032
1033/**
1034 * cipso_v4_map_cat_rng_hton - Perform a category mapping from host to network
1035 * @doi_def: the DOI definition
1036 * @secattr: the security attributes
1037 * @net_cat: the zero'd out category list in network/CIPSO format
1038 * @net_cat_len: the length of the CIPSO category list in bytes
1039 *
1040 * Description:
1041 * Perform a label mapping to translate a local MLS category bitmap to the
1042 * correct CIPSO category list using the given DOI definition.   Returns the
1043 * size in bytes of the network category bitmap on success, negative values
1044 * otherwise.
1045 *
1046 */
1047static int cipso_v4_map_cat_rng_hton(const struct cipso_v4_doi *doi_def,
1048				     const struct netlbl_lsm_secattr *secattr,
1049				     unsigned char *net_cat,
1050				     u32 net_cat_len)
1051{
1052	int iter = -1;
1053	u16 array[CIPSO_V4_TAG_RNG_CAT_MAX * 2];
1054	u32 array_cnt = 0;
1055	u32 cat_size = 0;
1056
1057	/* make sure we don't overflow the 'array[]' variable */
1058	if (net_cat_len >
1059	    (CIPSO_V4_OPT_LEN_MAX - CIPSO_V4_HDR_LEN - CIPSO_V4_TAG_RNG_BLEN))
1060		return -ENOSPC;
1061
1062	for (;;) {
1063		iter = netlbl_catmap_walk(secattr->attr.mls.cat, iter + 1);
1064		if (iter < 0)
1065			break;
1066		cat_size += (iter == 0 ? 0 : sizeof(u16));
1067		if (cat_size > net_cat_len)
1068			return -ENOSPC;
1069		array[array_cnt++] = iter;
1070
1071		iter = netlbl_catmap_walkrng(secattr->attr.mls.cat, iter);
1072		if (iter < 0)
1073			return -EFAULT;
1074		cat_size += sizeof(u16);
1075		if (cat_size > net_cat_len)
1076			return -ENOSPC;
1077		array[array_cnt++] = iter;
1078	}
1079
1080	for (iter = 0; array_cnt > 0;) {
1081		*((__be16 *)&net_cat[iter]) = htons(array[--array_cnt]);
1082		iter += 2;
1083		array_cnt--;
1084		if (array[array_cnt] != 0) {
1085			*((__be16 *)&net_cat[iter]) = htons(array[array_cnt]);
1086			iter += 2;
1087		}
1088	}
1089
1090	return cat_size;
1091}
1092
1093/**
1094 * cipso_v4_map_cat_rng_ntoh - Perform a category mapping from network to host
1095 * @doi_def: the DOI definition
1096 * @net_cat: the category list in network/CIPSO format
1097 * @net_cat_len: the length of the CIPSO bitmap in bytes
1098 * @secattr: the security attributes
1099 *
1100 * Description:
1101 * Perform a label mapping to translate a CIPSO category list to the correct
1102 * local MLS category bitmap using the given DOI definition.  Returns zero on
1103 * success, negative values on failure.
1104 *
1105 */
1106static int cipso_v4_map_cat_rng_ntoh(const struct cipso_v4_doi *doi_def,
1107				     const unsigned char *net_cat,
1108				     u32 net_cat_len,
1109				     struct netlbl_lsm_secattr *secattr)
1110{
1111	int ret_val;
1112	u32 net_iter;
1113	u16 cat_low;
1114	u16 cat_high;
1115
1116	for (net_iter = 0; net_iter < net_cat_len; net_iter += 4) {
1117		cat_high = get_unaligned_be16(&net_cat[net_iter]);
1118		if ((net_iter + 4) <= net_cat_len)
1119			cat_low = get_unaligned_be16(&net_cat[net_iter + 2]);
1120		else
1121			cat_low = 0;
1122
1123		ret_val = netlbl_catmap_setrng(&secattr->attr.mls.cat,
1124					       cat_low,
1125					       cat_high,
1126					       GFP_ATOMIC);
1127		if (ret_val != 0)
1128			return ret_val;
1129	}
1130
1131	return 0;
1132}
1133
1134/*
1135 * Protocol Handling Functions
1136 */
1137
1138/**
1139 * cipso_v4_gentag_hdr - Generate a CIPSO option header
1140 * @doi_def: the DOI definition
1141 * @len: the total tag length in bytes, not including this header
1142 * @buf: the CIPSO option buffer
1143 *
1144 * Description:
1145 * Write a CIPSO header into the beginning of @buffer.
1146 *
1147 */
1148static void cipso_v4_gentag_hdr(const struct cipso_v4_doi *doi_def,
1149				unsigned char *buf,
1150				u32 len)
1151{
1152	buf[0] = IPOPT_CIPSO;
1153	buf[1] = CIPSO_V4_HDR_LEN + len;
1154	put_unaligned_be32(doi_def->doi, &buf[2]);
1155}
1156
1157/**
1158 * cipso_v4_gentag_rbm - Generate a CIPSO restricted bitmap tag (type #1)
1159 * @doi_def: the DOI definition
1160 * @secattr: the security attributes
1161 * @buffer: the option buffer
1162 * @buffer_len: length of buffer in bytes
1163 *
1164 * Description:
1165 * Generate a CIPSO option using the restricted bitmap tag, tag type #1.  The
1166 * actual buffer length may be larger than the indicated size due to
1167 * translation between host and network category bitmaps.  Returns the size of
1168 * the tag on success, negative values on failure.
1169 *
1170 */
1171static int cipso_v4_gentag_rbm(const struct cipso_v4_doi *doi_def,
1172			       const struct netlbl_lsm_secattr *secattr,
1173			       unsigned char *buffer,
1174			       u32 buffer_len)
1175{
1176	int ret_val;
1177	u32 tag_len;
1178	u32 level;
1179
1180	if ((secattr->flags & NETLBL_SECATTR_MLS_LVL) == 0)
1181		return -EPERM;
1182
1183	ret_val = cipso_v4_map_lvl_hton(doi_def,
1184					secattr->attr.mls.lvl,
1185					&level);
1186	if (ret_val != 0)
1187		return ret_val;
1188
1189	if (secattr->flags & NETLBL_SECATTR_MLS_CAT) {
1190		ret_val = cipso_v4_map_cat_rbm_hton(doi_def,
1191						    secattr,
1192						    &buffer[4],
1193						    buffer_len - 4);
1194		if (ret_val < 0)
1195			return ret_val;
1196
1197		/* This will send packets using the "optimized" format when
1198		 * possible as specified in  section 3.4.2.6 of the
1199		 * CIPSO draft. */
1200		if (READ_ONCE(cipso_v4_rbm_optfmt) && ret_val > 0 &&
1201		    ret_val <= 10)
1202			tag_len = 14;
1203		else
1204			tag_len = 4 + ret_val;
1205	} else
1206		tag_len = 4;
1207
1208	buffer[0] = CIPSO_V4_TAG_RBITMAP;
1209	buffer[1] = tag_len;
1210	buffer[3] = level;
1211
1212	return tag_len;
1213}
1214
1215/**
1216 * cipso_v4_parsetag_rbm - Parse a CIPSO restricted bitmap tag
1217 * @doi_def: the DOI definition
1218 * @tag: the CIPSO tag
1219 * @secattr: the security attributes
1220 *
1221 * Description:
1222 * Parse a CIPSO restricted bitmap tag (tag type #1) and return the security
1223 * attributes in @secattr.  Return zero on success, negatives values on
1224 * failure.
1225 *
1226 */
1227static int cipso_v4_parsetag_rbm(const struct cipso_v4_doi *doi_def,
1228				 const unsigned char *tag,
1229				 struct netlbl_lsm_secattr *secattr)
1230{
1231	int ret_val;
1232	u8 tag_len = tag[1];
1233	u32 level;
1234
1235	ret_val = cipso_v4_map_lvl_ntoh(doi_def, tag[3], &level);
1236	if (ret_val != 0)
1237		return ret_val;
1238	secattr->attr.mls.lvl = level;
1239	secattr->flags |= NETLBL_SECATTR_MLS_LVL;
1240
1241	if (tag_len > 4) {
1242		ret_val = cipso_v4_map_cat_rbm_ntoh(doi_def,
1243						    &tag[4],
1244						    tag_len - 4,
1245						    secattr);
1246		if (ret_val != 0) {
1247			netlbl_catmap_free(secattr->attr.mls.cat);
1248			return ret_val;
1249		}
1250
1251		if (secattr->attr.mls.cat)
1252			secattr->flags |= NETLBL_SECATTR_MLS_CAT;
1253	}
1254
1255	return 0;
1256}
1257
1258/**
1259 * cipso_v4_gentag_enum - Generate a CIPSO enumerated tag (type #2)
1260 * @doi_def: the DOI definition
1261 * @secattr: the security attributes
1262 * @buffer: the option buffer
1263 * @buffer_len: length of buffer in bytes
1264 *
1265 * Description:
1266 * Generate a CIPSO option using the enumerated tag, tag type #2.  Returns the
1267 * size of the tag on success, negative values on failure.
1268 *
1269 */
1270static int cipso_v4_gentag_enum(const struct cipso_v4_doi *doi_def,
1271				const struct netlbl_lsm_secattr *secattr,
1272				unsigned char *buffer,
1273				u32 buffer_len)
1274{
1275	int ret_val;
1276	u32 tag_len;
1277	u32 level;
1278
1279	if (!(secattr->flags & NETLBL_SECATTR_MLS_LVL))
1280		return -EPERM;
1281
1282	ret_val = cipso_v4_map_lvl_hton(doi_def,
1283					secattr->attr.mls.lvl,
1284					&level);
1285	if (ret_val != 0)
1286		return ret_val;
1287
1288	if (secattr->flags & NETLBL_SECATTR_MLS_CAT) {
1289		ret_val = cipso_v4_map_cat_enum_hton(doi_def,
1290						     secattr,
1291						     &buffer[4],
1292						     buffer_len - 4);
1293		if (ret_val < 0)
1294			return ret_val;
1295
1296		tag_len = 4 + ret_val;
1297	} else
1298		tag_len = 4;
1299
1300	buffer[0] = CIPSO_V4_TAG_ENUM;
1301	buffer[1] = tag_len;
1302	buffer[3] = level;
1303
1304	return tag_len;
1305}
1306
1307/**
1308 * cipso_v4_parsetag_enum - Parse a CIPSO enumerated tag
1309 * @doi_def: the DOI definition
1310 * @tag: the CIPSO tag
1311 * @secattr: the security attributes
1312 *
1313 * Description:
1314 * Parse a CIPSO enumerated tag (tag type #2) and return the security
1315 * attributes in @secattr.  Return zero on success, negatives values on
1316 * failure.
1317 *
1318 */
1319static int cipso_v4_parsetag_enum(const struct cipso_v4_doi *doi_def,
1320				  const unsigned char *tag,
1321				  struct netlbl_lsm_secattr *secattr)
1322{
1323	int ret_val;
1324	u8 tag_len = tag[1];
1325	u32 level;
1326
1327	ret_val = cipso_v4_map_lvl_ntoh(doi_def, tag[3], &level);
1328	if (ret_val != 0)
1329		return ret_val;
1330	secattr->attr.mls.lvl = level;
1331	secattr->flags |= NETLBL_SECATTR_MLS_LVL;
1332
1333	if (tag_len > 4) {
1334		ret_val = cipso_v4_map_cat_enum_ntoh(doi_def,
1335						     &tag[4],
1336						     tag_len - 4,
1337						     secattr);
1338		if (ret_val != 0) {
1339			netlbl_catmap_free(secattr->attr.mls.cat);
1340			return ret_val;
1341		}
1342
1343		secattr->flags |= NETLBL_SECATTR_MLS_CAT;
1344	}
1345
1346	return 0;
1347}
1348
1349/**
1350 * cipso_v4_gentag_rng - Generate a CIPSO ranged tag (type #5)
1351 * @doi_def: the DOI definition
1352 * @secattr: the security attributes
1353 * @buffer: the option buffer
1354 * @buffer_len: length of buffer in bytes
1355 *
1356 * Description:
1357 * Generate a CIPSO option using the ranged tag, tag type #5.  Returns the
1358 * size of the tag on success, negative values on failure.
1359 *
1360 */
1361static int cipso_v4_gentag_rng(const struct cipso_v4_doi *doi_def,
1362			       const struct netlbl_lsm_secattr *secattr,
1363			       unsigned char *buffer,
1364			       u32 buffer_len)
1365{
1366	int ret_val;
1367	u32 tag_len;
1368	u32 level;
1369
1370	if (!(secattr->flags & NETLBL_SECATTR_MLS_LVL))
1371		return -EPERM;
1372
1373	ret_val = cipso_v4_map_lvl_hton(doi_def,
1374					secattr->attr.mls.lvl,
1375					&level);
1376	if (ret_val != 0)
1377		return ret_val;
1378
1379	if (secattr->flags & NETLBL_SECATTR_MLS_CAT) {
1380		ret_val = cipso_v4_map_cat_rng_hton(doi_def,
1381						    secattr,
1382						    &buffer[4],
1383						    buffer_len - 4);
1384		if (ret_val < 0)
1385			return ret_val;
1386
1387		tag_len = 4 + ret_val;
1388	} else
1389		tag_len = 4;
1390
1391	buffer[0] = CIPSO_V4_TAG_RANGE;
1392	buffer[1] = tag_len;
1393	buffer[3] = level;
1394
1395	return tag_len;
1396}
1397
1398/**
1399 * cipso_v4_parsetag_rng - Parse a CIPSO ranged tag
1400 * @doi_def: the DOI definition
1401 * @tag: the CIPSO tag
1402 * @secattr: the security attributes
1403 *
1404 * Description:
1405 * Parse a CIPSO ranged tag (tag type #5) and return the security attributes
1406 * in @secattr.  Return zero on success, negatives values on failure.
1407 *
1408 */
1409static int cipso_v4_parsetag_rng(const struct cipso_v4_doi *doi_def,
1410				 const unsigned char *tag,
1411				 struct netlbl_lsm_secattr *secattr)
1412{
1413	int ret_val;
1414	u8 tag_len = tag[1];
1415	u32 level;
1416
1417	ret_val = cipso_v4_map_lvl_ntoh(doi_def, tag[3], &level);
1418	if (ret_val != 0)
1419		return ret_val;
1420	secattr->attr.mls.lvl = level;
1421	secattr->flags |= NETLBL_SECATTR_MLS_LVL;
1422
1423	if (tag_len > 4) {
1424		ret_val = cipso_v4_map_cat_rng_ntoh(doi_def,
1425						    &tag[4],
1426						    tag_len - 4,
1427						    secattr);
1428		if (ret_val != 0) {
1429			netlbl_catmap_free(secattr->attr.mls.cat);
1430			return ret_val;
1431		}
1432
1433		if (secattr->attr.mls.cat)
1434			secattr->flags |= NETLBL_SECATTR_MLS_CAT;
1435	}
1436
1437	return 0;
1438}
1439
1440/**
1441 * cipso_v4_gentag_loc - Generate a CIPSO local tag (non-standard)
1442 * @doi_def: the DOI definition
1443 * @secattr: the security attributes
1444 * @buffer: the option buffer
1445 * @buffer_len: length of buffer in bytes
1446 *
1447 * Description:
1448 * Generate a CIPSO option using the local tag.  Returns the size of the tag
1449 * on success, negative values on failure.
1450 *
1451 */
1452static int cipso_v4_gentag_loc(const struct cipso_v4_doi *doi_def,
1453			       const struct netlbl_lsm_secattr *secattr,
1454			       unsigned char *buffer,
1455			       u32 buffer_len)
1456{
1457	if (!(secattr->flags & NETLBL_SECATTR_SECID))
1458		return -EPERM;
1459
1460	buffer[0] = CIPSO_V4_TAG_LOCAL;
1461	buffer[1] = CIPSO_V4_TAG_LOC_BLEN;
1462	*(u32 *)&buffer[2] = secattr->attr.secid;
1463
1464	return CIPSO_V4_TAG_LOC_BLEN;
1465}
1466
1467/**
1468 * cipso_v4_parsetag_loc - Parse a CIPSO local tag
1469 * @doi_def: the DOI definition
1470 * @tag: the CIPSO tag
1471 * @secattr: the security attributes
1472 *
1473 * Description:
1474 * Parse a CIPSO local tag and return the security attributes in @secattr.
1475 * Return zero on success, negatives values on failure.
1476 *
1477 */
1478static int cipso_v4_parsetag_loc(const struct cipso_v4_doi *doi_def,
1479				 const unsigned char *tag,
1480				 struct netlbl_lsm_secattr *secattr)
1481{
1482	secattr->attr.secid = *(u32 *)&tag[2];
1483	secattr->flags |= NETLBL_SECATTR_SECID;
1484
1485	return 0;
1486}
1487
1488/**
1489 * cipso_v4_optptr - Find the CIPSO option in the packet
1490 * @skb: the packet
1491 *
1492 * Description:
1493 * Parse the packet's IP header looking for a CIPSO option.  Returns a pointer
1494 * to the start of the CIPSO option on success, NULL if one is not found.
1495 *
1496 */
1497unsigned char *cipso_v4_optptr(const struct sk_buff *skb)
1498{
1499	const struct iphdr *iph = ip_hdr(skb);
1500	unsigned char *optptr = (unsigned char *)&(ip_hdr(skb)[1]);
1501	int optlen;
1502	int taglen;
1503
1504	for (optlen = iph->ihl*4 - sizeof(struct iphdr); optlen > 1; ) {
1505		switch (optptr[0]) {
1506		case IPOPT_END:
1507			return NULL;
1508		case IPOPT_NOOP:
1509			taglen = 1;
1510			break;
1511		default:
1512			taglen = optptr[1];
1513		}
1514		if (!taglen || taglen > optlen)
1515			return NULL;
1516		if (optptr[0] == IPOPT_CIPSO)
1517			return optptr;
1518
1519		optlen -= taglen;
1520		optptr += taglen;
1521	}
1522
1523	return NULL;
1524}
1525
1526/**
1527 * cipso_v4_validate - Validate a CIPSO option
1528 * @skb: the packet
1529 * @option: the start of the option, on error it is set to point to the error
1530 *
1531 * Description:
1532 * This routine is called to validate a CIPSO option, it checks all of the
1533 * fields to ensure that they are at least valid, see the draft snippet below
1534 * for details.  If the option is valid then a zero value is returned and
1535 * the value of @option is unchanged.  If the option is invalid then a
1536 * non-zero value is returned and @option is adjusted to point to the
1537 * offending portion of the option.  From the IETF draft ...
1538 *
1539 *  "If any field within the CIPSO options, such as the DOI identifier, is not
1540 *   recognized the IP datagram is discarded and an ICMP 'parameter problem'
1541 *   (type 12) is generated and returned.  The ICMP code field is set to 'bad
1542 *   parameter' (code 0) and the pointer is set to the start of the CIPSO field
1543 *   that is unrecognized."
1544 *
1545 */
1546int cipso_v4_validate(const struct sk_buff *skb, unsigned char **option)
1547{
1548	unsigned char *opt = *option;
1549	unsigned char *tag;
1550	unsigned char opt_iter;
1551	unsigned char err_offset = 0;
1552	u8 opt_len;
1553	u8 tag_len;
1554	struct cipso_v4_doi *doi_def = NULL;
1555	u32 tag_iter;
1556
1557	/* caller already checks for length values that are too large */
1558	opt_len = opt[1];
1559	if (opt_len < 8) {
1560		err_offset = 1;
1561		goto validate_return;
1562	}
1563
1564	rcu_read_lock();
1565	doi_def = cipso_v4_doi_search(get_unaligned_be32(&opt[2]));
1566	if (!doi_def) {
1567		err_offset = 2;
1568		goto validate_return_locked;
1569	}
1570
1571	opt_iter = CIPSO_V4_HDR_LEN;
1572	tag = opt + opt_iter;
1573	while (opt_iter < opt_len) {
1574		for (tag_iter = 0; doi_def->tags[tag_iter] != tag[0];)
1575			if (doi_def->tags[tag_iter] == CIPSO_V4_TAG_INVALID ||
1576			    ++tag_iter == CIPSO_V4_TAG_MAXCNT) {
1577				err_offset = opt_iter;
1578				goto validate_return_locked;
1579			}
1580
1581		if (opt_iter + 1 == opt_len) {
1582			err_offset = opt_iter;
1583			goto validate_return_locked;
1584		}
1585		tag_len = tag[1];
1586		if (tag_len > (opt_len - opt_iter)) {
1587			err_offset = opt_iter + 1;
1588			goto validate_return_locked;
1589		}
1590
1591		switch (tag[0]) {
1592		case CIPSO_V4_TAG_RBITMAP:
1593			if (tag_len < CIPSO_V4_TAG_RBM_BLEN) {
1594				err_offset = opt_iter + 1;
1595				goto validate_return_locked;
1596			}
1597
1598			/* We are already going to do all the verification
1599			 * necessary at the socket layer so from our point of
1600			 * view it is safe to turn these checks off (and less
1601			 * work), however, the CIPSO draft says we should do
1602			 * all the CIPSO validations here but it doesn't
1603			 * really specify _exactly_ what we need to validate
1604			 * ... so, just make it a sysctl tunable. */
1605			if (READ_ONCE(cipso_v4_rbm_strictvalid)) {
1606				if (cipso_v4_map_lvl_valid(doi_def,
1607							   tag[3]) < 0) {
1608					err_offset = opt_iter + 3;
1609					goto validate_return_locked;
1610				}
1611				if (tag_len > CIPSO_V4_TAG_RBM_BLEN &&
1612				    cipso_v4_map_cat_rbm_valid(doi_def,
1613							    &tag[4],
1614							    tag_len - 4) < 0) {
1615					err_offset = opt_iter + 4;
1616					goto validate_return_locked;
1617				}
1618			}
1619			break;
1620		case CIPSO_V4_TAG_ENUM:
1621			if (tag_len < CIPSO_V4_TAG_ENUM_BLEN) {
1622				err_offset = opt_iter + 1;
1623				goto validate_return_locked;
1624			}
1625
1626			if (cipso_v4_map_lvl_valid(doi_def,
1627						   tag[3]) < 0) {
1628				err_offset = opt_iter + 3;
1629				goto validate_return_locked;
1630			}
1631			if (tag_len > CIPSO_V4_TAG_ENUM_BLEN &&
1632			    cipso_v4_map_cat_enum_valid(doi_def,
1633							&tag[4],
1634							tag_len - 4) < 0) {
1635				err_offset = opt_iter + 4;
1636				goto validate_return_locked;
1637			}
1638			break;
1639		case CIPSO_V4_TAG_RANGE:
1640			if (tag_len < CIPSO_V4_TAG_RNG_BLEN) {
1641				err_offset = opt_iter + 1;
1642				goto validate_return_locked;
1643			}
1644
1645			if (cipso_v4_map_lvl_valid(doi_def,
1646						   tag[3]) < 0) {
1647				err_offset = opt_iter + 3;
1648				goto validate_return_locked;
1649			}
1650			if (tag_len > CIPSO_V4_TAG_RNG_BLEN &&
1651			    cipso_v4_map_cat_rng_valid(doi_def,
1652						       &tag[4],
1653						       tag_len - 4) < 0) {
1654				err_offset = opt_iter + 4;
1655				goto validate_return_locked;
1656			}
1657			break;
1658		case CIPSO_V4_TAG_LOCAL:
1659			/* This is a non-standard tag that we only allow for
1660			 * local connections, so if the incoming interface is
1661			 * not the loopback device drop the packet. Further,
1662			 * there is no legitimate reason for setting this from
1663			 * userspace so reject it if skb is NULL. */
1664			if (!skb || !(skb->dev->flags & IFF_LOOPBACK)) {
1665				err_offset = opt_iter;
1666				goto validate_return_locked;
1667			}
1668			if (tag_len != CIPSO_V4_TAG_LOC_BLEN) {
1669				err_offset = opt_iter + 1;
1670				goto validate_return_locked;
1671			}
1672			break;
1673		default:
1674			err_offset = opt_iter;
1675			goto validate_return_locked;
1676		}
1677
1678		tag += tag_len;
1679		opt_iter += tag_len;
1680	}
1681
1682validate_return_locked:
1683	rcu_read_unlock();
1684validate_return:
1685	*option = opt + err_offset;
1686	return err_offset;
1687}
1688
1689/**
1690 * cipso_v4_error - Send the correct response for a bad packet
1691 * @skb: the packet
1692 * @error: the error code
1693 * @gateway: CIPSO gateway flag
1694 *
1695 * Description:
1696 * Based on the error code given in @error, send an ICMP error message back to
1697 * the originating host.  From the IETF draft ...
1698 *
1699 *  "If the contents of the CIPSO [option] are valid but the security label is
1700 *   outside of the configured host or port label range, the datagram is
1701 *   discarded and an ICMP 'destination unreachable' (type 3) is generated and
1702 *   returned.  The code field of the ICMP is set to 'communication with
1703 *   destination network administratively prohibited' (code 9) or to
1704 *   'communication with destination host administratively prohibited'
1705 *   (code 10).  The value of the code is dependent on whether the originator
1706 *   of the ICMP message is acting as a CIPSO host or a CIPSO gateway.  The
1707 *   recipient of the ICMP message MUST be able to handle either value.  The
1708 *   same procedure is performed if a CIPSO [option] can not be added to an
1709 *   IP packet because it is too large to fit in the IP options area."
1710 *
1711 *  "If the error is triggered by receipt of an ICMP message, the message is
1712 *   discarded and no response is permitted (consistent with general ICMP
1713 *   processing rules)."
1714 *
1715 */
1716void cipso_v4_error(struct sk_buff *skb, int error, u32 gateway)
1717{
1718	struct inet_skb_parm parm;
1719	int res;
1720
1721	if (ip_hdr(skb)->protocol == IPPROTO_ICMP || error != -EACCES)
1722		return;
1723
1724	/*
1725	 * We might be called above the IP layer,
1726	 * so we can not use icmp_send and IPCB here.
1727	 */
1728
1729	memset(&parm, 0, sizeof(parm));
1730	parm.opt.optlen = ip_hdr(skb)->ihl * 4 - sizeof(struct iphdr);
1731	rcu_read_lock();
1732	res = __ip_options_compile(dev_net(skb->dev), &parm.opt, skb, NULL);
1733	rcu_read_unlock();
1734
1735	if (res)
1736		return;
1737
1738	if (gateway)
1739		__icmp_send(skb, ICMP_DEST_UNREACH, ICMP_NET_ANO, 0, &parm);
1740	else
1741		__icmp_send(skb, ICMP_DEST_UNREACH, ICMP_HOST_ANO, 0, &parm);
1742}
1743
1744/**
1745 * cipso_v4_genopt - Generate a CIPSO option
1746 * @buf: the option buffer
1747 * @buf_len: the size of opt_buf
1748 * @doi_def: the CIPSO DOI to use
1749 * @secattr: the security attributes
1750 *
1751 * Description:
1752 * Generate a CIPSO option using the DOI definition and security attributes
1753 * passed to the function.  Returns the length of the option on success and
1754 * negative values on failure.
1755 *
1756 */
1757static int cipso_v4_genopt(unsigned char *buf, u32 buf_len,
1758			   const struct cipso_v4_doi *doi_def,
1759			   const struct netlbl_lsm_secattr *secattr)
1760{
1761	int ret_val;
1762	u32 iter;
1763
1764	if (buf_len <= CIPSO_V4_HDR_LEN)
1765		return -ENOSPC;
1766
1767	/* XXX - This code assumes only one tag per CIPSO option which isn't
1768	 * really a good assumption to make but since we only support the MAC
1769	 * tags right now it is a safe assumption. */
1770	iter = 0;
1771	do {
1772		memset(buf, 0, buf_len);
1773		switch (doi_def->tags[iter]) {
1774		case CIPSO_V4_TAG_RBITMAP:
1775			ret_val = cipso_v4_gentag_rbm(doi_def,
1776						   secattr,
1777						   &buf[CIPSO_V4_HDR_LEN],
1778						   buf_len - CIPSO_V4_HDR_LEN);
1779			break;
1780		case CIPSO_V4_TAG_ENUM:
1781			ret_val = cipso_v4_gentag_enum(doi_def,
1782						   secattr,
1783						   &buf[CIPSO_V4_HDR_LEN],
1784						   buf_len - CIPSO_V4_HDR_LEN);
1785			break;
1786		case CIPSO_V4_TAG_RANGE:
1787			ret_val = cipso_v4_gentag_rng(doi_def,
1788						   secattr,
1789						   &buf[CIPSO_V4_HDR_LEN],
1790						   buf_len - CIPSO_V4_HDR_LEN);
1791			break;
1792		case CIPSO_V4_TAG_LOCAL:
1793			ret_val = cipso_v4_gentag_loc(doi_def,
1794						   secattr,
1795						   &buf[CIPSO_V4_HDR_LEN],
1796						   buf_len - CIPSO_V4_HDR_LEN);
1797			break;
1798		default:
1799			return -EPERM;
1800		}
1801
1802		iter++;
1803	} while (ret_val < 0 &&
1804		 iter < CIPSO_V4_TAG_MAXCNT &&
1805		 doi_def->tags[iter] != CIPSO_V4_TAG_INVALID);
1806	if (ret_val < 0)
1807		return ret_val;
1808	cipso_v4_gentag_hdr(doi_def, buf, ret_val);
1809	return CIPSO_V4_HDR_LEN + ret_val;
1810}
1811
1812static int cipso_v4_get_actual_opt_len(const unsigned char *data, int len)
1813{
1814	int iter = 0, optlen = 0;
1815
1816	/* determining the new total option length is tricky because of
1817	 * the padding necessary, the only thing i can think to do at
1818	 * this point is walk the options one-by-one, skipping the
1819	 * padding at the end to determine the actual option size and
1820	 * from there we can determine the new total option length
1821	 */
1822	while (iter < len) {
1823		if (data[iter] == IPOPT_END) {
1824			break;
1825		} else if (data[iter] == IPOPT_NOP) {
1826			iter++;
1827		} else {
1828			iter += data[iter + 1];
1829			optlen = iter;
1830		}
1831	}
1832	return optlen;
1833}
1834
1835/**
1836 * cipso_v4_sock_setattr - Add a CIPSO option to a socket
1837 * @sk: the socket
1838 * @doi_def: the CIPSO DOI to use
1839 * @secattr: the specific security attributes of the socket
1840 * @sk_locked: true if caller holds the socket lock
1841 *
1842 * Description:
1843 * Set the CIPSO option on the given socket using the DOI definition and
1844 * security attributes passed to the function.  This function requires
1845 * exclusive access to @sk, which means it either needs to be in the
1846 * process of being created or locked.  Returns zero on success and negative
1847 * values on failure.
1848 *
1849 */
1850int cipso_v4_sock_setattr(struct sock *sk,
1851			  const struct cipso_v4_doi *doi_def,
1852			  const struct netlbl_lsm_secattr *secattr,
1853			  bool sk_locked)
1854{
1855	int ret_val = -EPERM;
1856	unsigned char *buf = NULL;
1857	u32 buf_len;
1858	u32 opt_len;
1859	struct ip_options_rcu *old, *opt = NULL;
1860	struct inet_sock *sk_inet;
1861	struct inet_connection_sock *sk_conn;
1862
1863	/* In the case of sock_create_lite(), the sock->sk field is not
1864	 * defined yet but it is not a problem as the only users of these
1865	 * "lite" PF_INET sockets are functions which do an accept() call
1866	 * afterwards so we will label the socket as part of the accept(). */
1867	if (!sk)
1868		return 0;
1869
1870	/* We allocate the maximum CIPSO option size here so we are probably
1871	 * being a little wasteful, but it makes our life _much_ easier later
1872	 * on and after all we are only talking about 40 bytes. */
1873	buf_len = CIPSO_V4_OPT_LEN_MAX;
1874	buf = kmalloc(buf_len, GFP_ATOMIC);
1875	if (!buf) {
1876		ret_val = -ENOMEM;
1877		goto socket_setattr_failure;
1878	}
1879
1880	ret_val = cipso_v4_genopt(buf, buf_len, doi_def, secattr);
1881	if (ret_val < 0)
1882		goto socket_setattr_failure;
1883	buf_len = ret_val;
1884
1885	/* We can't use ip_options_get() directly because it makes a call to
1886	 * ip_options_get_alloc() which allocates memory with GFP_KERNEL and
1887	 * we won't always have CAP_NET_RAW even though we _always_ want to
1888	 * set the IPOPT_CIPSO option. */
1889	opt_len = (buf_len + 3) & ~3;
1890	opt = kzalloc(sizeof(*opt) + opt_len, GFP_ATOMIC);
1891	if (!opt) {
1892		ret_val = -ENOMEM;
1893		goto socket_setattr_failure;
1894	}
1895	memcpy(opt->opt.__data, buf, buf_len);
1896	opt->opt.optlen = opt_len;
1897	opt->opt.cipso = sizeof(struct iphdr);
1898	kfree(buf);
1899	buf = NULL;
1900
1901	sk_inet = inet_sk(sk);
1902
1903	old = rcu_dereference_protected(sk_inet->inet_opt, sk_locked);
1904	if (inet_test_bit(IS_ICSK, sk)) {
1905		sk_conn = inet_csk(sk);
1906		if (old)
1907			sk_conn->icsk_ext_hdr_len -= old->opt.optlen;
1908		sk_conn->icsk_ext_hdr_len += opt->opt.optlen;
1909		sk_conn->icsk_sync_mss(sk, sk_conn->icsk_pmtu_cookie);
1910	}
1911	rcu_assign_pointer(sk_inet->inet_opt, opt);
1912	if (old)
1913		kfree_rcu(old, rcu);
1914
1915	return 0;
1916
1917socket_setattr_failure:
1918	kfree(buf);
1919	kfree(opt);
1920	return ret_val;
1921}
1922
1923/**
1924 * cipso_v4_req_setattr - Add a CIPSO option to a connection request socket
1925 * @req: the connection request socket
1926 * @doi_def: the CIPSO DOI to use
1927 * @secattr: the specific security attributes of the socket
1928 *
1929 * Description:
1930 * Set the CIPSO option on the given socket using the DOI definition and
1931 * security attributes passed to the function.  Returns zero on success and
1932 * negative values on failure.
1933 *
1934 */
1935int cipso_v4_req_setattr(struct request_sock *req,
1936			 const struct cipso_v4_doi *doi_def,
1937			 const struct netlbl_lsm_secattr *secattr)
1938{
1939	int ret_val = -EPERM;
1940	unsigned char *buf = NULL;
1941	u32 buf_len;
1942	u32 opt_len;
1943	struct ip_options_rcu *opt = NULL;
1944	struct inet_request_sock *req_inet;
1945
1946	/* We allocate the maximum CIPSO option size here so we are probably
1947	 * being a little wasteful, but it makes our life _much_ easier later
1948	 * on and after all we are only talking about 40 bytes. */
1949	buf_len = CIPSO_V4_OPT_LEN_MAX;
1950	buf = kmalloc(buf_len, GFP_ATOMIC);
1951	if (!buf) {
1952		ret_val = -ENOMEM;
1953		goto req_setattr_failure;
1954	}
1955
1956	ret_val = cipso_v4_genopt(buf, buf_len, doi_def, secattr);
1957	if (ret_val < 0)
1958		goto req_setattr_failure;
1959	buf_len = ret_val;
1960
1961	/* We can't use ip_options_get() directly because it makes a call to
1962	 * ip_options_get_alloc() which allocates memory with GFP_KERNEL and
1963	 * we won't always have CAP_NET_RAW even though we _always_ want to
1964	 * set the IPOPT_CIPSO option. */
1965	opt_len = (buf_len + 3) & ~3;
1966	opt = kzalloc(sizeof(*opt) + opt_len, GFP_ATOMIC);
1967	if (!opt) {
1968		ret_val = -ENOMEM;
1969		goto req_setattr_failure;
1970	}
1971	memcpy(opt->opt.__data, buf, buf_len);
1972	opt->opt.optlen = opt_len;
1973	opt->opt.cipso = sizeof(struct iphdr);
1974	kfree(buf);
1975	buf = NULL;
1976
1977	req_inet = inet_rsk(req);
1978	opt = unrcu_pointer(xchg(&req_inet->ireq_opt, RCU_INITIALIZER(opt)));
1979	if (opt)
1980		kfree_rcu(opt, rcu);
1981
1982	return 0;
1983
1984req_setattr_failure:
1985	kfree(buf);
1986	kfree(opt);
1987	return ret_val;
1988}
1989
1990/**
1991 * cipso_v4_delopt - Delete the CIPSO option from a set of IP options
1992 * @opt_ptr: IP option pointer
1993 *
1994 * Description:
1995 * Deletes the CIPSO IP option from a set of IP options and makes the necessary
1996 * adjustments to the IP option structure.  Returns zero on success, negative
1997 * values on failure.
1998 *
1999 */
2000static int cipso_v4_delopt(struct ip_options_rcu __rcu **opt_ptr)
2001{
2002	struct ip_options_rcu *opt = rcu_dereference_protected(*opt_ptr, 1);
2003	int hdr_delta = 0;
2004
2005	if (!opt || opt->opt.cipso == 0)
2006		return 0;
2007	if (opt->opt.srr || opt->opt.rr || opt->opt.ts || opt->opt.router_alert) {
2008		u8 cipso_len;
2009		u8 cipso_off;
2010		unsigned char *cipso_ptr;
2011		int optlen_new;
2012
2013		cipso_off = opt->opt.cipso - sizeof(struct iphdr);
2014		cipso_ptr = &opt->opt.__data[cipso_off];
2015		cipso_len = cipso_ptr[1];
2016
2017		if (opt->opt.srr > opt->opt.cipso)
2018			opt->opt.srr -= cipso_len;
2019		if (opt->opt.rr > opt->opt.cipso)
2020			opt->opt.rr -= cipso_len;
2021		if (opt->opt.ts > opt->opt.cipso)
2022			opt->opt.ts -= cipso_len;
2023		if (opt->opt.router_alert > opt->opt.cipso)
2024			opt->opt.router_alert -= cipso_len;
2025		opt->opt.cipso = 0;
2026
2027		memmove(cipso_ptr, cipso_ptr + cipso_len,
2028			opt->opt.optlen - cipso_off - cipso_len);
2029
2030		optlen_new = cipso_v4_get_actual_opt_len(opt->opt.__data,
2031							 opt->opt.optlen);
2032		hdr_delta = opt->opt.optlen;
2033		opt->opt.optlen = (optlen_new + 3) & ~3;
2034		hdr_delta -= opt->opt.optlen;
2035	} else {
2036		/* only the cipso option was present on the socket so we can
2037		 * remove the entire option struct */
2038		*opt_ptr = NULL;
2039		hdr_delta = opt->opt.optlen;
2040		kfree_rcu(opt, rcu);
2041	}
2042
2043	return hdr_delta;
2044}
2045
2046/**
2047 * cipso_v4_sock_delattr - Delete the CIPSO option from a socket
2048 * @sk: the socket
2049 *
2050 * Description:
2051 * Removes the CIPSO option from a socket, if present.
2052 *
2053 */
2054void cipso_v4_sock_delattr(struct sock *sk)
2055{
2056	struct inet_sock *sk_inet;
2057	int hdr_delta;
2058
2059	sk_inet = inet_sk(sk);
2060
2061	hdr_delta = cipso_v4_delopt(&sk_inet->inet_opt);
2062	if (inet_test_bit(IS_ICSK, sk) && hdr_delta > 0) {
2063		struct inet_connection_sock *sk_conn = inet_csk(sk);
2064		sk_conn->icsk_ext_hdr_len -= hdr_delta;
2065		sk_conn->icsk_sync_mss(sk, sk_conn->icsk_pmtu_cookie);
2066	}
2067}
2068
2069/**
2070 * cipso_v4_req_delattr - Delete the CIPSO option from a request socket
2071 * @req: the request socket
2072 *
2073 * Description:
2074 * Removes the CIPSO option from a request socket, if present.
2075 *
2076 */
2077void cipso_v4_req_delattr(struct request_sock *req)
2078{
2079	cipso_v4_delopt(&inet_rsk(req)->ireq_opt);
2080}
2081
2082/**
2083 * cipso_v4_getattr - Helper function for the cipso_v4_*_getattr functions
2084 * @cipso: the CIPSO v4 option
2085 * @secattr: the security attributes
2086 *
2087 * Description:
2088 * Inspect @cipso and return the security attributes in @secattr.  Returns zero
2089 * on success and negative values on failure.
2090 *
2091 */
2092int cipso_v4_getattr(const unsigned char *cipso,
2093		     struct netlbl_lsm_secattr *secattr)
2094{
2095	int ret_val = -ENOMSG;
2096	u32 doi;
2097	struct cipso_v4_doi *doi_def;
2098
2099	if (cipso_v4_cache_check(cipso, cipso[1], secattr) == 0)
2100		return 0;
2101
2102	doi = get_unaligned_be32(&cipso[2]);
2103	rcu_read_lock();
2104	doi_def = cipso_v4_doi_search(doi);
2105	if (!doi_def)
2106		goto getattr_return;
2107	/* XXX - This code assumes only one tag per CIPSO option which isn't
2108	 * really a good assumption to make but since we only support the MAC
2109	 * tags right now it is a safe assumption. */
2110	switch (cipso[6]) {
2111	case CIPSO_V4_TAG_RBITMAP:
2112		ret_val = cipso_v4_parsetag_rbm(doi_def, &cipso[6], secattr);
2113		break;
2114	case CIPSO_V4_TAG_ENUM:
2115		ret_val = cipso_v4_parsetag_enum(doi_def, &cipso[6], secattr);
2116		break;
2117	case CIPSO_V4_TAG_RANGE:
2118		ret_val = cipso_v4_parsetag_rng(doi_def, &cipso[6], secattr);
2119		break;
2120	case CIPSO_V4_TAG_LOCAL:
2121		ret_val = cipso_v4_parsetag_loc(doi_def, &cipso[6], secattr);
2122		break;
2123	}
2124	if (ret_val == 0)
2125		secattr->type = NETLBL_NLTYPE_CIPSOV4;
2126
2127getattr_return:
2128	rcu_read_unlock();
2129	return ret_val;
2130}
2131
2132/**
2133 * cipso_v4_sock_getattr - Get the security attributes from a sock
2134 * @sk: the sock
2135 * @secattr: the security attributes
2136 *
2137 * Description:
2138 * Query @sk to see if there is a CIPSO option attached to the sock and if
2139 * there is return the CIPSO security attributes in @secattr.  This function
2140 * requires that @sk be locked, or privately held, but it does not do any
2141 * locking itself.  Returns zero on success and negative values on failure.
2142 *
2143 */
2144int cipso_v4_sock_getattr(struct sock *sk, struct netlbl_lsm_secattr *secattr)
2145{
2146	struct ip_options_rcu *opt;
2147	int res = -ENOMSG;
2148
2149	rcu_read_lock();
2150	opt = rcu_dereference(inet_sk(sk)->inet_opt);
2151	if (opt && opt->opt.cipso)
2152		res = cipso_v4_getattr(opt->opt.__data +
2153						opt->opt.cipso -
2154						sizeof(struct iphdr),
2155				       secattr);
2156	rcu_read_unlock();
2157	return res;
2158}
2159
2160/**
2161 * cipso_v4_skbuff_setattr - Set the CIPSO option on a packet
2162 * @skb: the packet
2163 * @doi_def: the DOI structure
2164 * @secattr: the security attributes
2165 *
2166 * Description:
2167 * Set the CIPSO option on the given packet based on the security attributes.
2168 * Returns a pointer to the IP header on success and NULL on failure.
2169 *
2170 */
2171int cipso_v4_skbuff_setattr(struct sk_buff *skb,
2172			    const struct cipso_v4_doi *doi_def,
2173			    const struct netlbl_lsm_secattr *secattr)
2174{
2175	int ret_val;
2176	struct iphdr *iph;
2177	struct ip_options *opt = &IPCB(skb)->opt;
2178	unsigned char buf[CIPSO_V4_OPT_LEN_MAX];
2179	u32 buf_len = CIPSO_V4_OPT_LEN_MAX;
2180	u32 opt_len;
2181	int len_delta;
2182
2183	ret_val = cipso_v4_genopt(buf, buf_len, doi_def, secattr);
2184	if (ret_val < 0)
2185		return ret_val;
2186	buf_len = ret_val;
2187	opt_len = (buf_len + 3) & ~3;
2188
2189	/* we overwrite any existing options to ensure that we have enough
2190	 * room for the CIPSO option, the reason is that we _need_ to guarantee
2191	 * that the security label is applied to the packet - we do the same
2192	 * thing when using the socket options and it hasn't caused a problem,
2193	 * if we need to we can always revisit this choice later */
2194
2195	len_delta = opt_len - opt->optlen;
2196	/* if we don't ensure enough headroom we could panic on the skb_push()
2197	 * call below so make sure we have enough, we are also "mangling" the
2198	 * packet so we should probably do a copy-on-write call anyway */
2199	ret_val = skb_cow(skb, skb_headroom(skb) + len_delta);
2200	if (ret_val < 0)
2201		return ret_val;
2202
2203	if (len_delta > 0) {
2204		/* we assume that the header + opt->optlen have already been
2205		 * "pushed" in ip_options_build() or similar */
2206		iph = ip_hdr(skb);
2207		skb_push(skb, len_delta);
2208		memmove((char *)iph - len_delta, iph, iph->ihl << 2);
2209		skb_reset_network_header(skb);
2210		iph = ip_hdr(skb);
2211	} else if (len_delta < 0) {
2212		iph = ip_hdr(skb);
2213		memset(iph + 1, IPOPT_NOP, opt->optlen);
2214	} else
2215		iph = ip_hdr(skb);
2216
2217	if (opt->optlen > 0)
2218		memset(opt, 0, sizeof(*opt));
2219	opt->optlen = opt_len;
2220	opt->cipso = sizeof(struct iphdr);
2221	opt->is_changed = 1;
2222
2223	/* we have to do the following because we are being called from a
2224	 * netfilter hook which means the packet already has had the header
2225	 * fields populated and the checksum calculated - yes this means we
2226	 * are doing more work than needed but we do it to keep the core
2227	 * stack clean and tidy */
2228	memcpy(iph + 1, buf, buf_len);
2229	if (opt_len > buf_len)
2230		memset((char *)(iph + 1) + buf_len, 0, opt_len - buf_len);
2231	if (len_delta != 0) {
2232		iph->ihl = 5 + (opt_len >> 2);
2233		iph_set_totlen(iph, skb->len);
2234	}
2235	ip_send_check(iph);
2236
2237	return 0;
2238}
2239
2240/**
2241 * cipso_v4_skbuff_delattr - Delete any CIPSO options from a packet
2242 * @skb: the packet
2243 *
2244 * Description:
2245 * Removes any and all CIPSO options from the given packet.  Returns zero on
2246 * success, negative values on failure.
2247 *
2248 */
2249int cipso_v4_skbuff_delattr(struct sk_buff *skb)
2250{
2251	int ret_val, cipso_len, hdr_len_actual, new_hdr_len_actual, new_hdr_len,
2252	    hdr_len_delta;
2253	struct iphdr *iph;
2254	struct ip_options *opt = &IPCB(skb)->opt;
2255	unsigned char *cipso_ptr;
2256
2257	if (opt->cipso == 0)
2258		return 0;
2259
2260	/* since we are changing the packet we should make a copy */
2261	ret_val = skb_cow(skb, skb_headroom(skb));
2262	if (ret_val < 0)
2263		return ret_val;
2264
2265	iph = ip_hdr(skb);
2266	cipso_ptr = (unsigned char *)iph + opt->cipso;
2267	cipso_len = cipso_ptr[1];
2268
2269	hdr_len_actual = sizeof(struct iphdr) +
2270			 cipso_v4_get_actual_opt_len((unsigned char *)(iph + 1),
2271						     opt->optlen);
2272	new_hdr_len_actual = hdr_len_actual - cipso_len;
2273	new_hdr_len = (new_hdr_len_actual + 3) & ~3;
2274	hdr_len_delta = (iph->ihl << 2) - new_hdr_len;
2275
2276	/* 1. shift any options after CIPSO to the left */
2277	memmove(cipso_ptr, cipso_ptr + cipso_len,
2278		new_hdr_len_actual - opt->cipso);
2279	/* 2. move the whole IP header to its new place */
2280	memmove((unsigned char *)iph + hdr_len_delta, iph, new_hdr_len_actual);
2281	/* 3. adjust the skb layout */
2282	skb_pull(skb, hdr_len_delta);
2283	skb_reset_network_header(skb);
2284	iph = ip_hdr(skb);
2285	/* 4. re-fill new padding with IPOPT_END (may now be longer) */
2286	memset((unsigned char *)iph + new_hdr_len_actual, IPOPT_END,
2287	       new_hdr_len - new_hdr_len_actual);
2288
2289	opt->optlen -= hdr_len_delta;
2290	opt->cipso = 0;
2291	opt->is_changed = 1;
2292	if (hdr_len_delta != 0) {
2293		iph->ihl = new_hdr_len >> 2;
2294		iph_set_totlen(iph, skb->len);
2295	}
2296	ip_send_check(iph);
2297
2298	return 0;
2299}
2300
2301/*
2302 * Setup Functions
2303 */
2304
2305/**
2306 * cipso_v4_init - Initialize the CIPSO module
2307 *
2308 * Description:
2309 * Initialize the CIPSO module and prepare it for use.  Returns zero on success
2310 * and negative values on failure.
2311 *
2312 */
2313static int __init cipso_v4_init(void)
2314{
2315	int ret_val;
2316
2317	ret_val = cipso_v4_cache_init();
2318	if (ret_val != 0)
2319		panic("Failed to initialize the CIPSO/IPv4 cache (%d)\n",
2320		      ret_val);
2321
2322	return 0;
2323}
2324
2325subsys_initcall(cipso_v4_init);