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