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.  Returns zero on
 191 * success and negative values on failure.
 192 *
 193 */
 194void cipso_v4_cache_invalidate(void)
 195{
 196	struct cipso_v4_map_cache_entry *entry, *tmp_entry;
 197	u32 iter;
 198
 199	for (iter = 0; iter < CIPSO_V4_CACHE_BUCKETS; iter++) {
 200		spin_lock_bh(&cipso_v4_cache[iter].lock);
 201		list_for_each_entry_safe(entry,
 202					 tmp_entry,
 203					 &cipso_v4_cache[iter].list, list) {
 204			list_del(&entry->list);
 205			cipso_v4_cache_entry_free(entry);
 206		}
 207		cipso_v4_cache[iter].size = 0;
 208		spin_unlock_bh(&cipso_v4_cache[iter].lock);
 209	}
 210}
 211
 212/**
 213 * cipso_v4_cache_check - Check the CIPSO cache for a label mapping
 214 * @key: the buffer to check
 215 * @key_len: buffer length in bytes
 216 * @secattr: the security attribute struct to use
 217 *
 218 * Description:
 219 * This function checks the cache to see if a label mapping already exists for
 220 * the given key.  If there is a match then the cache is adjusted and the
 221 * @secattr struct is populated with the correct LSM security attributes.  The
 222 * cache is adjusted in the following manner if the entry is not already the
 223 * first in the cache bucket:
 224 *
 225 *  1. The cache entry's activity counter is incremented
 226 *  2. The previous (higher ranking) entry's activity counter is decremented
 227 *  3. If the difference between the two activity counters is geater than
 228 *     CIPSO_V4_CACHE_REORDERLIMIT the two entries are swapped
 229 *
 230 * Returns zero on success, -ENOENT for a cache miss, and other negative values
 231 * on error.
 232 *
 233 */
 234static int cipso_v4_cache_check(const unsigned char *key,
 235				u32 key_len,
 236				struct netlbl_lsm_secattr *secattr)
 237{
 238	u32 bkt;
 239	struct cipso_v4_map_cache_entry *entry;
 240	struct cipso_v4_map_cache_entry *prev_entry = NULL;
 241	u32 hash;
 242
 243	if (!cipso_v4_cache_enabled)
 244		return -ENOENT;
 245
 246	hash = cipso_v4_map_cache_hash(key, key_len);
 247	bkt = hash & (CIPSO_V4_CACHE_BUCKETS - 1);
 248	spin_lock_bh(&cipso_v4_cache[bkt].lock);
 249	list_for_each_entry(entry, &cipso_v4_cache[bkt].list, list) {
 250		if (entry->hash == hash &&
 251		    entry->key_len == key_len &&
 252		    memcmp(entry->key, key, key_len) == 0) {
 253			entry->activity += 1;
 254			refcount_inc(&entry->lsm_data->refcount);
 255			secattr->cache = entry->lsm_data;
 256			secattr->flags |= NETLBL_SECATTR_CACHE;
 257			secattr->type = NETLBL_NLTYPE_CIPSOV4;
 258			if (!prev_entry) {
 259				spin_unlock_bh(&cipso_v4_cache[bkt].lock);
 260				return 0;
 261			}
 262
 263			if (prev_entry->activity > 0)
 264				prev_entry->activity -= 1;
 265			if (entry->activity > prev_entry->activity &&
 266			    entry->activity - prev_entry->activity >
 267			    CIPSO_V4_CACHE_REORDERLIMIT) {
 268				__list_del(entry->list.prev, entry->list.next);
 269				__list_add(&entry->list,
 270					   prev_entry->list.prev,
 271					   &prev_entry->list);
 272			}
 273
 274			spin_unlock_bh(&cipso_v4_cache[bkt].lock);
 275			return 0;
 276		}
 277		prev_entry = entry;
 278	}
 279	spin_unlock_bh(&cipso_v4_cache[bkt].lock);
 280
 281	return -ENOENT;
 282}
 283
 284/**
 285 * cipso_v4_cache_add - Add an entry to the CIPSO cache
 286 * @cipso_ptr: pointer to CIPSO IP option
 287 * @secattr: the packet's security attributes
 288 *
 289 * Description:
 290 * Add a new entry into the CIPSO label mapping cache.  Add the new entry to
 291 * head of the cache bucket's list, if the cache bucket is out of room remove
 292 * the last entry in the list first.  It is important to note that there is
 293 * currently no checking for duplicate keys.  Returns zero on success,
 294 * negative values on failure.
 295 *
 296 */
 297int cipso_v4_cache_add(const unsigned char *cipso_ptr,
 298		       const struct netlbl_lsm_secattr *secattr)
 299{
 
 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 (!cipso_v4_cache_enabled || cipso_v4_cache_bucketsize <= 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 < cipso_v4_cache_bucketsize) {
 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		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_secid: the LSM secid to use in the audit message
 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	if (!refcount_dec_and_test(&doi_def->refcount)) {
 523		spin_unlock(&cipso_v4_doi_list_lock);
 524		ret_val = -EBUSY;
 525		goto doi_remove_return;
 526	}
 527	list_del_rcu(&doi_def->list);
 528	spin_unlock(&cipso_v4_doi_list_lock);
 529
 530	cipso_v4_cache_invalidate();
 531	call_rcu(&doi_def->rcu, cipso_v4_doi_free_rcu);
 532	ret_val = 0;
 533
 534doi_remove_return:
 535	audit_buf = netlbl_audit_start(AUDIT_MAC_CIPSOV4_DEL, audit_info);
 536	if (audit_buf) {
 537		audit_log_format(audit_buf,
 538				 " cipso_doi=%u res=%u",
 539				 doi, ret_val == 0 ? 1 : 0);
 540		audit_log_end(audit_buf);
 541	}
 542
 543	return ret_val;
 544}
 545
 546/**
 547 * cipso_v4_doi_getdef - Returns a reference to a valid DOI definition
 548 * @doi: the DOI value
 549 *
 550 * Description:
 551 * Searches for a valid DOI definition and if one is found it is returned to
 552 * the caller.  Otherwise NULL is returned.  The caller must ensure that
 553 * rcu_read_lock() is held while accessing the returned definition and the DOI
 554 * definition reference count is decremented when the caller is done.
 555 *
 556 */
 557struct cipso_v4_doi *cipso_v4_doi_getdef(u32 doi)
 558{
 559	struct cipso_v4_doi *doi_def;
 560
 561	rcu_read_lock();
 562	doi_def = cipso_v4_doi_search(doi);
 563	if (!doi_def)
 564		goto doi_getdef_return;
 565	if (!refcount_inc_not_zero(&doi_def->refcount))
 566		doi_def = NULL;
 567
 568doi_getdef_return:
 569	rcu_read_unlock();
 570	return doi_def;
 571}
 572
 573/**
 574 * cipso_v4_doi_putdef - Releases a reference for the given DOI definition
 575 * @doi_def: the DOI definition
 576 *
 577 * Description:
 578 * Releases a DOI definition reference obtained from cipso_v4_doi_getdef().
 579 *
 580 */
 581void cipso_v4_doi_putdef(struct cipso_v4_doi *doi_def)
 582{
 583	if (!doi_def)
 584		return;
 585
 586	if (!refcount_dec_and_test(&doi_def->refcount))
 587		return;
 588	spin_lock(&cipso_v4_doi_list_lock);
 589	list_del_rcu(&doi_def->list);
 590	spin_unlock(&cipso_v4_doi_list_lock);
 591
 592	cipso_v4_cache_invalidate();
 593	call_rcu(&doi_def->rcu, cipso_v4_doi_free_rcu);
 594}
 595
 596/**
 597 * cipso_v4_doi_walk - Iterate through the DOI definitions
 598 * @skip_cnt: skip past this number of DOI definitions, updated
 599 * @callback: callback for each DOI definition
 600 * @cb_arg: argument for the callback function
 601 *
 602 * Description:
 603 * Iterate over the DOI definition list, skipping the first @skip_cnt entries.
 604 * For each entry call @callback, if @callback returns a negative value stop
 605 * 'walking' through the list and return.  Updates the value in @skip_cnt upon
 606 * return.  Returns zero on success, negative values on failure.
 607 *
 608 */
 609int cipso_v4_doi_walk(u32 *skip_cnt,
 610		     int (*callback) (struct cipso_v4_doi *doi_def, void *arg),
 611		     void *cb_arg)
 612{
 613	int ret_val = -ENOENT;
 614	u32 doi_cnt = 0;
 615	struct cipso_v4_doi *iter_doi;
 616
 617	rcu_read_lock();
 618	list_for_each_entry_rcu(iter_doi, &cipso_v4_doi_list, list)
 619		if (refcount_read(&iter_doi->refcount) > 0) {
 620			if (doi_cnt++ < *skip_cnt)
 621				continue;
 622			ret_val = callback(iter_doi, cb_arg);
 623			if (ret_val < 0) {
 624				doi_cnt--;
 625				goto doi_walk_return;
 626			}
 627		}
 628
 629doi_walk_return:
 630	rcu_read_unlock();
 631	*skip_cnt = doi_cnt;
 632	return ret_val;
 633}
 634
 635/*
 636 * Label Mapping Functions
 637 */
 638
 639/**
 640 * cipso_v4_map_lvl_valid - Checks to see if the given level is understood
 641 * @doi_def: the DOI definition
 642 * @level: the level to check
 643 *
 644 * Description:
 645 * Checks the given level against the given DOI definition and returns a
 646 * negative value if the level does not have a valid mapping and a zero value
 647 * if the level is defined by the DOI.
 648 *
 649 */
 650static int cipso_v4_map_lvl_valid(const struct cipso_v4_doi *doi_def, u8 level)
 651{
 652	switch (doi_def->type) {
 653	case CIPSO_V4_MAP_PASS:
 654		return 0;
 655	case CIPSO_V4_MAP_TRANS:
 656		if ((level < doi_def->map.std->lvl.cipso_size) &&
 657		    (doi_def->map.std->lvl.cipso[level] < CIPSO_V4_INV_LVL))
 658			return 0;
 659		break;
 660	}
 661
 662	return -EFAULT;
 663}
 664
 665/**
 666 * cipso_v4_map_lvl_hton - Perform a level mapping from the host to the network
 667 * @doi_def: the DOI definition
 668 * @host_lvl: the host MLS level
 669 * @net_lvl: the network/CIPSO MLS level
 670 *
 671 * Description:
 672 * Perform a label mapping to translate a local MLS level to the correct
 673 * CIPSO level using the given DOI definition.  Returns zero on success,
 674 * negative values otherwise.
 675 *
 676 */
 677static int cipso_v4_map_lvl_hton(const struct cipso_v4_doi *doi_def,
 678				 u32 host_lvl,
 679				 u32 *net_lvl)
 680{
 681	switch (doi_def->type) {
 682	case CIPSO_V4_MAP_PASS:
 683		*net_lvl = host_lvl;
 684		return 0;
 685	case CIPSO_V4_MAP_TRANS:
 686		if (host_lvl < doi_def->map.std->lvl.local_size &&
 687		    doi_def->map.std->lvl.local[host_lvl] < CIPSO_V4_INV_LVL) {
 688			*net_lvl = doi_def->map.std->lvl.local[host_lvl];
 689			return 0;
 690		}
 691		return -EPERM;
 692	}
 693
 694	return -EINVAL;
 695}
 696
 697/**
 698 * cipso_v4_map_lvl_ntoh - Perform a level mapping from the network to the host
 699 * @doi_def: the DOI definition
 700 * @net_lvl: the network/CIPSO MLS level
 701 * @host_lvl: the host MLS level
 702 *
 703 * Description:
 704 * Perform a label mapping to translate a CIPSO level to the correct local MLS
 705 * level using the given DOI definition.  Returns zero on success, negative
 706 * values otherwise.
 707 *
 708 */
 709static int cipso_v4_map_lvl_ntoh(const struct cipso_v4_doi *doi_def,
 710				 u32 net_lvl,
 711				 u32 *host_lvl)
 712{
 713	struct cipso_v4_std_map_tbl *map_tbl;
 714
 715	switch (doi_def->type) {
 716	case CIPSO_V4_MAP_PASS:
 717		*host_lvl = net_lvl;
 718		return 0;
 719	case CIPSO_V4_MAP_TRANS:
 720		map_tbl = doi_def->map.std;
 721		if (net_lvl < map_tbl->lvl.cipso_size &&
 722		    map_tbl->lvl.cipso[net_lvl] < CIPSO_V4_INV_LVL) {
 723			*host_lvl = doi_def->map.std->lvl.cipso[net_lvl];
 724			return 0;
 725		}
 726		return -EPERM;
 727	}
 728
 729	return -EINVAL;
 730}
 731
 732/**
 733 * cipso_v4_map_cat_rbm_valid - Checks to see if the category bitmap is valid
 734 * @doi_def: the DOI definition
 735 * @bitmap: category bitmap
 736 * @bitmap_len: bitmap length in bytes
 737 *
 738 * Description:
 739 * Checks the given category bitmap against the given DOI definition and
 740 * returns a negative value if any of the categories in the bitmap do not have
 741 * a valid mapping and a zero value if all of the categories are valid.
 742 *
 743 */
 744static int cipso_v4_map_cat_rbm_valid(const struct cipso_v4_doi *doi_def,
 745				      const unsigned char *bitmap,
 746				      u32 bitmap_len)
 747{
 748	int cat = -1;
 749	u32 bitmap_len_bits = bitmap_len * 8;
 750	u32 cipso_cat_size;
 751	u32 *cipso_array;
 752
 753	switch (doi_def->type) {
 754	case CIPSO_V4_MAP_PASS:
 755		return 0;
 756	case CIPSO_V4_MAP_TRANS:
 757		cipso_cat_size = doi_def->map.std->cat.cipso_size;
 758		cipso_array = doi_def->map.std->cat.cipso;
 759		for (;;) {
 760			cat = netlbl_bitmap_walk(bitmap,
 761						 bitmap_len_bits,
 762						 cat + 1,
 763						 1);
 764			if (cat < 0)
 765				break;
 766			if (cat >= cipso_cat_size ||
 767			    cipso_array[cat] >= CIPSO_V4_INV_CAT)
 768				return -EFAULT;
 769		}
 770
 771		if (cat == -1)
 772			return 0;
 773		break;
 774	}
 775
 776	return -EFAULT;
 777}
 778
 779/**
 780 * cipso_v4_map_cat_rbm_hton - Perform a category mapping from host to network
 781 * @doi_def: the DOI definition
 782 * @secattr: the security attributes
 783 * @net_cat: the zero'd out category bitmap in network/CIPSO format
 784 * @net_cat_len: the length of the CIPSO bitmap in bytes
 785 *
 786 * Description:
 787 * Perform a label mapping to translate a local MLS category bitmap to the
 788 * correct CIPSO bitmap using the given DOI definition.  Returns the minimum
 789 * size in bytes of the network bitmap on success, negative values otherwise.
 790 *
 791 */
 792static int cipso_v4_map_cat_rbm_hton(const struct cipso_v4_doi *doi_def,
 793				     const struct netlbl_lsm_secattr *secattr,
 794				     unsigned char *net_cat,
 795				     u32 net_cat_len)
 796{
 797	int host_spot = -1;
 798	u32 net_spot = CIPSO_V4_INV_CAT;
 799	u32 net_spot_max = 0;
 800	u32 net_clen_bits = net_cat_len * 8;
 801	u32 host_cat_size = 0;
 802	u32 *host_cat_array = NULL;
 803
 804	if (doi_def->type == CIPSO_V4_MAP_TRANS) {
 805		host_cat_size = doi_def->map.std->cat.local_size;
 806		host_cat_array = doi_def->map.std->cat.local;
 807	}
 808
 809	for (;;) {
 810		host_spot = netlbl_catmap_walk(secattr->attr.mls.cat,
 811					       host_spot + 1);
 812		if (host_spot < 0)
 813			break;
 814
 815		switch (doi_def->type) {
 816		case CIPSO_V4_MAP_PASS:
 817			net_spot = host_spot;
 818			break;
 819		case CIPSO_V4_MAP_TRANS:
 820			if (host_spot >= host_cat_size)
 821				return -EPERM;
 822			net_spot = host_cat_array[host_spot];
 823			if (net_spot >= CIPSO_V4_INV_CAT)
 824				return -EPERM;
 825			break;
 826		}
 827		if (net_spot >= net_clen_bits)
 828			return -ENOSPC;
 829		netlbl_bitmap_setbit(net_cat, net_spot, 1);
 830
 831		if (net_spot > net_spot_max)
 832			net_spot_max = net_spot;
 833	}
 834
 835	if (++net_spot_max % 8)
 836		return net_spot_max / 8 + 1;
 837	return net_spot_max / 8;
 838}
 839
 840/**
 841 * cipso_v4_map_cat_rbm_ntoh - Perform a category mapping from network to host
 842 * @doi_def: the DOI definition
 843 * @net_cat: the category bitmap in network/CIPSO format
 844 * @net_cat_len: the length of the CIPSO bitmap in bytes
 845 * @secattr: the security attributes
 846 *
 847 * Description:
 848 * Perform a label mapping to translate a CIPSO bitmap to the correct local
 849 * MLS category bitmap using the given DOI definition.  Returns zero on
 850 * success, negative values on failure.
 851 *
 852 */
 853static int cipso_v4_map_cat_rbm_ntoh(const struct cipso_v4_doi *doi_def,
 854				     const unsigned char *net_cat,
 855				     u32 net_cat_len,
 856				     struct netlbl_lsm_secattr *secattr)
 857{
 858	int ret_val;
 859	int net_spot = -1;
 860	u32 host_spot = CIPSO_V4_INV_CAT;
 861	u32 net_clen_bits = net_cat_len * 8;
 862	u32 net_cat_size = 0;
 863	u32 *net_cat_array = NULL;
 864
 865	if (doi_def->type == CIPSO_V4_MAP_TRANS) {
 866		net_cat_size = doi_def->map.std->cat.cipso_size;
 867		net_cat_array = doi_def->map.std->cat.cipso;
 868	}
 869
 870	for (;;) {
 871		net_spot = netlbl_bitmap_walk(net_cat,
 872					      net_clen_bits,
 873					      net_spot + 1,
 874					      1);
 875		if (net_spot < 0) {
 876			if (net_spot == -2)
 877				return -EFAULT;
 878			return 0;
 879		}
 880
 881		switch (doi_def->type) {
 882		case CIPSO_V4_MAP_PASS:
 883			host_spot = net_spot;
 884			break;
 885		case CIPSO_V4_MAP_TRANS:
 886			if (net_spot >= net_cat_size)
 887				return -EPERM;
 888			host_spot = net_cat_array[net_spot];
 889			if (host_spot >= CIPSO_V4_INV_CAT)
 890				return -EPERM;
 891			break;
 892		}
 893		ret_val = netlbl_catmap_setbit(&secattr->attr.mls.cat,
 894						       host_spot,
 895						       GFP_ATOMIC);
 896		if (ret_val != 0)
 897			return ret_val;
 898	}
 899
 900	return -EINVAL;
 901}
 902
 903/**
 904 * cipso_v4_map_cat_enum_valid - Checks to see if the categories are valid
 905 * @doi_def: the DOI definition
 906 * @enumcat: category list
 907 * @enumcat_len: length of the category list in bytes
 908 *
 909 * Description:
 910 * Checks the given categories against the given DOI definition and returns a
 911 * negative value if any of the categories do not have a valid mapping and a
 912 * zero value if all of the categories are valid.
 913 *
 914 */
 915static int cipso_v4_map_cat_enum_valid(const struct cipso_v4_doi *doi_def,
 916				       const unsigned char *enumcat,
 917				       u32 enumcat_len)
 918{
 919	u16 cat;
 920	int cat_prev = -1;
 921	u32 iter;
 922
 923	if (doi_def->type != CIPSO_V4_MAP_PASS || enumcat_len & 0x01)
 924		return -EFAULT;
 925
 926	for (iter = 0; iter < enumcat_len; iter += 2) {
 927		cat = get_unaligned_be16(&enumcat[iter]);
 928		if (cat <= cat_prev)
 929			return -EFAULT;
 930		cat_prev = cat;
 931	}
 932
 933	return 0;
 934}
 935
 936/**
 937 * cipso_v4_map_cat_enum_hton - Perform a category mapping from host to network
 938 * @doi_def: the DOI definition
 939 * @secattr: the security attributes
 940 * @net_cat: the zero'd out category list in network/CIPSO format
 941 * @net_cat_len: the length of the CIPSO category list in bytes
 942 *
 943 * Description:
 944 * Perform a label mapping to translate a local MLS category bitmap to the
 945 * correct CIPSO category list using the given DOI definition.   Returns the
 946 * size in bytes of the network category bitmap on success, negative values
 947 * otherwise.
 948 *
 949 */
 950static int cipso_v4_map_cat_enum_hton(const struct cipso_v4_doi *doi_def,
 951				      const struct netlbl_lsm_secattr *secattr,
 952				      unsigned char *net_cat,
 953				      u32 net_cat_len)
 954{
 955	int cat = -1;
 956	u32 cat_iter = 0;
 957
 958	for (;;) {
 959		cat = netlbl_catmap_walk(secattr->attr.mls.cat, cat + 1);
 960		if (cat < 0)
 961			break;
 962		if ((cat_iter + 2) > net_cat_len)
 963			return -ENOSPC;
 964
 965		*((__be16 *)&net_cat[cat_iter]) = htons(cat);
 966		cat_iter += 2;
 967	}
 968
 969	return cat_iter;
 970}
 971
 972/**
 973 * cipso_v4_map_cat_enum_ntoh - Perform a category mapping from network to host
 974 * @doi_def: the DOI definition
 975 * @net_cat: the category list in network/CIPSO format
 976 * @net_cat_len: the length of the CIPSO bitmap in bytes
 977 * @secattr: the security attributes
 978 *
 979 * Description:
 980 * Perform a label mapping to translate a CIPSO category list to the correct
 981 * local MLS category bitmap using the given DOI definition.  Returns zero on
 982 * success, negative values on failure.
 983 *
 984 */
 985static int cipso_v4_map_cat_enum_ntoh(const struct cipso_v4_doi *doi_def,
 986				      const unsigned char *net_cat,
 987				      u32 net_cat_len,
 988				      struct netlbl_lsm_secattr *secattr)
 989{
 990	int ret_val;
 991	u32 iter;
 992
 993	for (iter = 0; iter < net_cat_len; iter += 2) {
 994		ret_val = netlbl_catmap_setbit(&secattr->attr.mls.cat,
 995					     get_unaligned_be16(&net_cat[iter]),
 996					     GFP_ATOMIC);
 997		if (ret_val != 0)
 998			return ret_val;
 999	}
1000
1001	return 0;
1002}
1003
1004/**
1005 * cipso_v4_map_cat_rng_valid - Checks to see if the categories are valid
1006 * @doi_def: the DOI definition
1007 * @rngcat: category list
1008 * @rngcat_len: length of the category list in bytes
1009 *
1010 * Description:
1011 * Checks the given categories against the given DOI definition and returns a
1012 * negative value if any of the categories do not have a valid mapping and a
1013 * zero value if all of the categories are valid.
1014 *
1015 */
1016static int cipso_v4_map_cat_rng_valid(const struct cipso_v4_doi *doi_def,
1017				      const unsigned char *rngcat,
1018				      u32 rngcat_len)
1019{
1020	u16 cat_high;
1021	u16 cat_low;
1022	u32 cat_prev = CIPSO_V4_MAX_REM_CATS + 1;
1023	u32 iter;
1024
1025	if (doi_def->type != CIPSO_V4_MAP_PASS || rngcat_len & 0x01)
1026		return -EFAULT;
1027
1028	for (iter = 0; iter < rngcat_len; iter += 4) {
1029		cat_high = get_unaligned_be16(&rngcat[iter]);
1030		if ((iter + 4) <= rngcat_len)
1031			cat_low = get_unaligned_be16(&rngcat[iter + 2]);
1032		else
1033			cat_low = 0;
1034
1035		if (cat_high > cat_prev)
1036			return -EFAULT;
1037
1038		cat_prev = cat_low;
1039	}
1040
1041	return 0;
1042}
1043
1044/**
1045 * cipso_v4_map_cat_rng_hton - Perform a category mapping from host to network
1046 * @doi_def: the DOI definition
1047 * @secattr: the security attributes
1048 * @net_cat: the zero'd out category list in network/CIPSO format
1049 * @net_cat_len: the length of the CIPSO category list in bytes
1050 *
1051 * Description:
1052 * Perform a label mapping to translate a local MLS category bitmap to the
1053 * correct CIPSO category list using the given DOI definition.   Returns the
1054 * size in bytes of the network category bitmap on success, negative values
1055 * otherwise.
1056 *
1057 */
1058static int cipso_v4_map_cat_rng_hton(const struct cipso_v4_doi *doi_def,
1059				     const struct netlbl_lsm_secattr *secattr,
1060				     unsigned char *net_cat,
1061				     u32 net_cat_len)
1062{
1063	int iter = -1;
1064	u16 array[CIPSO_V4_TAG_RNG_CAT_MAX * 2];
1065	u32 array_cnt = 0;
1066	u32 cat_size = 0;
1067
1068	/* make sure we don't overflow the 'array[]' variable */
1069	if (net_cat_len >
1070	    (CIPSO_V4_OPT_LEN_MAX - CIPSO_V4_HDR_LEN - CIPSO_V4_TAG_RNG_BLEN))
1071		return -ENOSPC;
1072
1073	for (;;) {
1074		iter = netlbl_catmap_walk(secattr->attr.mls.cat, iter + 1);
1075		if (iter < 0)
1076			break;
1077		cat_size += (iter == 0 ? 0 : sizeof(u16));
1078		if (cat_size > net_cat_len)
1079			return -ENOSPC;
1080		array[array_cnt++] = iter;
1081
1082		iter = netlbl_catmap_walkrng(secattr->attr.mls.cat, iter);
1083		if (iter < 0)
1084			return -EFAULT;
1085		cat_size += sizeof(u16);
1086		if (cat_size > net_cat_len)
1087			return -ENOSPC;
1088		array[array_cnt++] = iter;
1089	}
1090
1091	for (iter = 0; array_cnt > 0;) {
1092		*((__be16 *)&net_cat[iter]) = htons(array[--array_cnt]);
1093		iter += 2;
1094		array_cnt--;
1095		if (array[array_cnt] != 0) {
1096			*((__be16 *)&net_cat[iter]) = htons(array[array_cnt]);
1097			iter += 2;
1098		}
1099	}
1100
1101	return cat_size;
1102}
1103
1104/**
1105 * cipso_v4_map_cat_rng_ntoh - Perform a category mapping from network to host
1106 * @doi_def: the DOI definition
1107 * @net_cat: the category list in network/CIPSO format
1108 * @net_cat_len: the length of the CIPSO bitmap in bytes
1109 * @secattr: the security attributes
1110 *
1111 * Description:
1112 * Perform a label mapping to translate a CIPSO category list to the correct
1113 * local MLS category bitmap using the given DOI definition.  Returns zero on
1114 * success, negative values on failure.
1115 *
1116 */
1117static int cipso_v4_map_cat_rng_ntoh(const struct cipso_v4_doi *doi_def,
1118				     const unsigned char *net_cat,
1119				     u32 net_cat_len,
1120				     struct netlbl_lsm_secattr *secattr)
1121{
1122	int ret_val;
1123	u32 net_iter;
1124	u16 cat_low;
1125	u16 cat_high;
1126
1127	for (net_iter = 0; net_iter < net_cat_len; net_iter += 4) {
1128		cat_high = get_unaligned_be16(&net_cat[net_iter]);
1129		if ((net_iter + 4) <= net_cat_len)
1130			cat_low = get_unaligned_be16(&net_cat[net_iter + 2]);
1131		else
1132			cat_low = 0;
1133
1134		ret_val = netlbl_catmap_setrng(&secattr->attr.mls.cat,
1135					       cat_low,
1136					       cat_high,
1137					       GFP_ATOMIC);
1138		if (ret_val != 0)
1139			return ret_val;
1140	}
1141
1142	return 0;
1143}
1144
1145/*
1146 * Protocol Handling Functions
1147 */
1148
1149/**
1150 * cipso_v4_gentag_hdr - Generate a CIPSO option header
1151 * @doi_def: the DOI definition
1152 * @len: the total tag length in bytes, not including this header
1153 * @buf: the CIPSO option buffer
1154 *
1155 * Description:
1156 * Write a CIPSO header into the beginning of @buffer.
1157 *
1158 */
1159static void cipso_v4_gentag_hdr(const struct cipso_v4_doi *doi_def,
1160				unsigned char *buf,
1161				u32 len)
1162{
1163	buf[0] = IPOPT_CIPSO;
1164	buf[1] = CIPSO_V4_HDR_LEN + len;
1165	*(__be32 *)&buf[2] = htonl(doi_def->doi);
1166}
1167
1168/**
1169 * cipso_v4_gentag_rbm - Generate a CIPSO restricted bitmap tag (type #1)
1170 * @doi_def: the DOI definition
1171 * @secattr: the security attributes
1172 * @buffer: the option buffer
1173 * @buffer_len: length of buffer in bytes
1174 *
1175 * Description:
1176 * Generate a CIPSO option using the restricted bitmap tag, tag type #1.  The
1177 * actual buffer length may be larger than the indicated size due to
1178 * translation between host and network category bitmaps.  Returns the size of
1179 * the tag on success, negative values on failure.
1180 *
1181 */
1182static int cipso_v4_gentag_rbm(const struct cipso_v4_doi *doi_def,
1183			       const struct netlbl_lsm_secattr *secattr,
1184			       unsigned char *buffer,
1185			       u32 buffer_len)
1186{
1187	int ret_val;
1188	u32 tag_len;
1189	u32 level;
1190
1191	if ((secattr->flags & NETLBL_SECATTR_MLS_LVL) == 0)
1192		return -EPERM;
1193
1194	ret_val = cipso_v4_map_lvl_hton(doi_def,
1195					secattr->attr.mls.lvl,
1196					&level);
1197	if (ret_val != 0)
1198		return ret_val;
1199
1200	if (secattr->flags & NETLBL_SECATTR_MLS_CAT) {
1201		ret_val = cipso_v4_map_cat_rbm_hton(doi_def,
1202						    secattr,
1203						    &buffer[4],
1204						    buffer_len - 4);
1205		if (ret_val < 0)
1206			return ret_val;
1207
1208		/* This will send packets using the "optimized" format when
1209		 * possible as specified in  section 3.4.2.6 of the
1210		 * CIPSO draft. */
1211		if (cipso_v4_rbm_optfmt && ret_val > 0 && ret_val <= 10)
 
1212			tag_len = 14;
1213		else
1214			tag_len = 4 + ret_val;
1215	} else
1216		tag_len = 4;
1217
1218	buffer[0] = CIPSO_V4_TAG_RBITMAP;
1219	buffer[1] = tag_len;
1220	buffer[3] = level;
1221
1222	return tag_len;
1223}
1224
1225/**
1226 * cipso_v4_parsetag_rbm - Parse a CIPSO restricted bitmap tag
1227 * @doi_def: the DOI definition
1228 * @tag: the CIPSO tag
1229 * @secattr: the security attributes
1230 *
1231 * Description:
1232 * Parse a CIPSO restricted bitmap tag (tag type #1) and return the security
1233 * attributes in @secattr.  Return zero on success, negatives values on
1234 * failure.
1235 *
1236 */
1237static int cipso_v4_parsetag_rbm(const struct cipso_v4_doi *doi_def,
1238				 const unsigned char *tag,
1239				 struct netlbl_lsm_secattr *secattr)
1240{
1241	int ret_val;
1242	u8 tag_len = tag[1];
1243	u32 level;
1244
1245	ret_val = cipso_v4_map_lvl_ntoh(doi_def, tag[3], &level);
1246	if (ret_val != 0)
1247		return ret_val;
1248	secattr->attr.mls.lvl = level;
1249	secattr->flags |= NETLBL_SECATTR_MLS_LVL;
1250
1251	if (tag_len > 4) {
1252		ret_val = cipso_v4_map_cat_rbm_ntoh(doi_def,
1253						    &tag[4],
1254						    tag_len - 4,
1255						    secattr);
1256		if (ret_val != 0) {
1257			netlbl_catmap_free(secattr->attr.mls.cat);
1258			return ret_val;
1259		}
1260
1261		if (secattr->attr.mls.cat)
1262			secattr->flags |= NETLBL_SECATTR_MLS_CAT;
1263	}
1264
1265	return 0;
1266}
1267
1268/**
1269 * cipso_v4_gentag_enum - Generate a CIPSO enumerated tag (type #2)
1270 * @doi_def: the DOI definition
1271 * @secattr: the security attributes
1272 * @buffer: the option buffer
1273 * @buffer_len: length of buffer in bytes
1274 *
1275 * Description:
1276 * Generate a CIPSO option using the enumerated tag, tag type #2.  Returns the
1277 * size of the tag on success, negative values on failure.
1278 *
1279 */
1280static int cipso_v4_gentag_enum(const struct cipso_v4_doi *doi_def,
1281				const struct netlbl_lsm_secattr *secattr,
1282				unsigned char *buffer,
1283				u32 buffer_len)
1284{
1285	int ret_val;
1286	u32 tag_len;
1287	u32 level;
1288
1289	if (!(secattr->flags & NETLBL_SECATTR_MLS_LVL))
1290		return -EPERM;
1291
1292	ret_val = cipso_v4_map_lvl_hton(doi_def,
1293					secattr->attr.mls.lvl,
1294					&level);
1295	if (ret_val != 0)
1296		return ret_val;
1297
1298	if (secattr->flags & NETLBL_SECATTR_MLS_CAT) {
1299		ret_val = cipso_v4_map_cat_enum_hton(doi_def,
1300						     secattr,
1301						     &buffer[4],
1302						     buffer_len - 4);
1303		if (ret_val < 0)
1304			return ret_val;
1305
1306		tag_len = 4 + ret_val;
1307	} else
1308		tag_len = 4;
1309
1310	buffer[0] = CIPSO_V4_TAG_ENUM;
1311	buffer[1] = tag_len;
1312	buffer[3] = level;
1313
1314	return tag_len;
1315}
1316
1317/**
1318 * cipso_v4_parsetag_enum - Parse a CIPSO enumerated tag
1319 * @doi_def: the DOI definition
1320 * @tag: the CIPSO tag
1321 * @secattr: the security attributes
1322 *
1323 * Description:
1324 * Parse a CIPSO enumerated tag (tag type #2) and return the security
1325 * attributes in @secattr.  Return zero on success, negatives values on
1326 * failure.
1327 *
1328 */
1329static int cipso_v4_parsetag_enum(const struct cipso_v4_doi *doi_def,
1330				  const unsigned char *tag,
1331				  struct netlbl_lsm_secattr *secattr)
1332{
1333	int ret_val;
1334	u8 tag_len = tag[1];
1335	u32 level;
1336
1337	ret_val = cipso_v4_map_lvl_ntoh(doi_def, tag[3], &level);
1338	if (ret_val != 0)
1339		return ret_val;
1340	secattr->attr.mls.lvl = level;
1341	secattr->flags |= NETLBL_SECATTR_MLS_LVL;
1342
1343	if (tag_len > 4) {
1344		ret_val = cipso_v4_map_cat_enum_ntoh(doi_def,
1345						     &tag[4],
1346						     tag_len - 4,
1347						     secattr);
1348		if (ret_val != 0) {
1349			netlbl_catmap_free(secattr->attr.mls.cat);
1350			return ret_val;
1351		}
1352
1353		secattr->flags |= NETLBL_SECATTR_MLS_CAT;
1354	}
1355
1356	return 0;
1357}
1358
1359/**
1360 * cipso_v4_gentag_rng - Generate a CIPSO ranged tag (type #5)
1361 * @doi_def: the DOI definition
1362 * @secattr: the security attributes
1363 * @buffer: the option buffer
1364 * @buffer_len: length of buffer in bytes
1365 *
1366 * Description:
1367 * Generate a CIPSO option using the ranged tag, tag type #5.  Returns the
1368 * size of the tag on success, negative values on failure.
1369 *
1370 */
1371static int cipso_v4_gentag_rng(const struct cipso_v4_doi *doi_def,
1372			       const struct netlbl_lsm_secattr *secattr,
1373			       unsigned char *buffer,
1374			       u32 buffer_len)
1375{
1376	int ret_val;
1377	u32 tag_len;
1378	u32 level;
1379
1380	if (!(secattr->flags & NETLBL_SECATTR_MLS_LVL))
1381		return -EPERM;
1382
1383	ret_val = cipso_v4_map_lvl_hton(doi_def,
1384					secattr->attr.mls.lvl,
1385					&level);
1386	if (ret_val != 0)
1387		return ret_val;
1388
1389	if (secattr->flags & NETLBL_SECATTR_MLS_CAT) {
1390		ret_val = cipso_v4_map_cat_rng_hton(doi_def,
1391						    secattr,
1392						    &buffer[4],
1393						    buffer_len - 4);
1394		if (ret_val < 0)
1395			return ret_val;
1396
1397		tag_len = 4 + ret_val;
1398	} else
1399		tag_len = 4;
1400
1401	buffer[0] = CIPSO_V4_TAG_RANGE;
1402	buffer[1] = tag_len;
1403	buffer[3] = level;
1404
1405	return tag_len;
1406}
1407
1408/**
1409 * cipso_v4_parsetag_rng - Parse a CIPSO ranged tag
1410 * @doi_def: the DOI definition
1411 * @tag: the CIPSO tag
1412 * @secattr: the security attributes
1413 *
1414 * Description:
1415 * Parse a CIPSO ranged tag (tag type #5) and return the security attributes
1416 * in @secattr.  Return zero on success, negatives values on failure.
1417 *
1418 */
1419static int cipso_v4_parsetag_rng(const struct cipso_v4_doi *doi_def,
1420				 const unsigned char *tag,
1421				 struct netlbl_lsm_secattr *secattr)
1422{
1423	int ret_val;
1424	u8 tag_len = tag[1];
1425	u32 level;
1426
1427	ret_val = cipso_v4_map_lvl_ntoh(doi_def, tag[3], &level);
1428	if (ret_val != 0)
1429		return ret_val;
1430	secattr->attr.mls.lvl = level;
1431	secattr->flags |= NETLBL_SECATTR_MLS_LVL;
1432
1433	if (tag_len > 4) {
1434		ret_val = cipso_v4_map_cat_rng_ntoh(doi_def,
1435						    &tag[4],
1436						    tag_len - 4,
1437						    secattr);
1438		if (ret_val != 0) {
1439			netlbl_catmap_free(secattr->attr.mls.cat);
1440			return ret_val;
1441		}
1442
1443		if (secattr->attr.mls.cat)
1444			secattr->flags |= NETLBL_SECATTR_MLS_CAT;
1445	}
1446
1447	return 0;
1448}
1449
1450/**
1451 * cipso_v4_gentag_loc - Generate a CIPSO local tag (non-standard)
1452 * @doi_def: the DOI definition
1453 * @secattr: the security attributes
1454 * @buffer: the option buffer
1455 * @buffer_len: length of buffer in bytes
1456 *
1457 * Description:
1458 * Generate a CIPSO option using the local tag.  Returns the size of the tag
1459 * on success, negative values on failure.
1460 *
1461 */
1462static int cipso_v4_gentag_loc(const struct cipso_v4_doi *doi_def,
1463			       const struct netlbl_lsm_secattr *secattr,
1464			       unsigned char *buffer,
1465			       u32 buffer_len)
1466{
1467	if (!(secattr->flags & NETLBL_SECATTR_SECID))
1468		return -EPERM;
1469
1470	buffer[0] = CIPSO_V4_TAG_LOCAL;
1471	buffer[1] = CIPSO_V4_TAG_LOC_BLEN;
1472	*(u32 *)&buffer[2] = secattr->attr.secid;
1473
1474	return CIPSO_V4_TAG_LOC_BLEN;
1475}
1476
1477/**
1478 * cipso_v4_parsetag_loc - Parse a CIPSO local tag
1479 * @doi_def: the DOI definition
1480 * @tag: the CIPSO tag
1481 * @secattr: the security attributes
1482 *
1483 * Description:
1484 * Parse a CIPSO local tag and return the security attributes in @secattr.
1485 * Return zero on success, negatives values on failure.
1486 *
1487 */
1488static int cipso_v4_parsetag_loc(const struct cipso_v4_doi *doi_def,
1489				 const unsigned char *tag,
1490				 struct netlbl_lsm_secattr *secattr)
1491{
1492	secattr->attr.secid = *(u32 *)&tag[2];
1493	secattr->flags |= NETLBL_SECATTR_SECID;
1494
1495	return 0;
1496}
1497
1498/**
1499 * cipso_v4_optptr - Find the CIPSO option in the packet
1500 * @skb: the packet
1501 *
1502 * Description:
1503 * Parse the packet's IP header looking for a CIPSO option.  Returns a pointer
1504 * to the start of the CIPSO option on success, NULL if one is not found.
1505 *
1506 */
1507unsigned char *cipso_v4_optptr(const struct sk_buff *skb)
1508{
1509	const struct iphdr *iph = ip_hdr(skb);
1510	unsigned char *optptr = (unsigned char *)&(ip_hdr(skb)[1]);
1511	int optlen;
1512	int taglen;
1513
1514	for (optlen = iph->ihl*4 - sizeof(struct iphdr); optlen > 1; ) {
1515		switch (optptr[0]) {
1516		case IPOPT_END:
1517			return NULL;
1518		case IPOPT_NOOP:
1519			taglen = 1;
1520			break;
1521		default:
1522			taglen = optptr[1];
1523		}
1524		if (!taglen || taglen > optlen)
1525			return NULL;
1526		if (optptr[0] == IPOPT_CIPSO)
1527			return optptr;
1528
1529		optlen -= taglen;
1530		optptr += taglen;
1531	}
1532
1533	return NULL;
1534}
1535
1536/**
1537 * cipso_v4_validate - Validate a CIPSO option
1538 * @skb: the packet
1539 * @option: the start of the option, on error it is set to point to the error
1540 *
1541 * Description:
1542 * This routine is called to validate a CIPSO option, it checks all of the
1543 * fields to ensure that they are at least valid, see the draft snippet below
1544 * for details.  If the option is valid then a zero value is returned and
1545 * the value of @option is unchanged.  If the option is invalid then a
1546 * non-zero value is returned and @option is adjusted to point to the
1547 * offending portion of the option.  From the IETF draft ...
1548 *
1549 *  "If any field within the CIPSO options, such as the DOI identifier, is not
1550 *   recognized the IP datagram is discarded and an ICMP 'parameter problem'
1551 *   (type 12) is generated and returned.  The ICMP code field is set to 'bad
1552 *   parameter' (code 0) and the pointer is set to the start of the CIPSO field
1553 *   that is unrecognized."
1554 *
1555 */
1556int cipso_v4_validate(const struct sk_buff *skb, unsigned char **option)
1557{
1558	unsigned char *opt = *option;
1559	unsigned char *tag;
1560	unsigned char opt_iter;
1561	unsigned char err_offset = 0;
1562	u8 opt_len;
1563	u8 tag_len;
1564	struct cipso_v4_doi *doi_def = NULL;
1565	u32 tag_iter;
1566
1567	/* caller already checks for length values that are too large */
1568	opt_len = opt[1];
1569	if (opt_len < 8) {
1570		err_offset = 1;
1571		goto validate_return;
1572	}
1573
1574	rcu_read_lock();
1575	doi_def = cipso_v4_doi_search(get_unaligned_be32(&opt[2]));
1576	if (!doi_def) {
1577		err_offset = 2;
1578		goto validate_return_locked;
1579	}
1580
1581	opt_iter = CIPSO_V4_HDR_LEN;
1582	tag = opt + opt_iter;
1583	while (opt_iter < opt_len) {
1584		for (tag_iter = 0; doi_def->tags[tag_iter] != tag[0];)
1585			if (doi_def->tags[tag_iter] == CIPSO_V4_TAG_INVALID ||
1586			    ++tag_iter == CIPSO_V4_TAG_MAXCNT) {
1587				err_offset = opt_iter;
1588				goto validate_return_locked;
1589			}
1590
1591		if (opt_iter + 1 == opt_len) {
1592			err_offset = opt_iter;
1593			goto validate_return_locked;
1594		}
1595		tag_len = tag[1];
1596		if (tag_len > (opt_len - opt_iter)) {
1597			err_offset = opt_iter + 1;
1598			goto validate_return_locked;
1599		}
1600
1601		switch (tag[0]) {
1602		case CIPSO_V4_TAG_RBITMAP:
1603			if (tag_len < CIPSO_V4_TAG_RBM_BLEN) {
1604				err_offset = opt_iter + 1;
1605				goto validate_return_locked;
1606			}
1607
1608			/* We are already going to do all the verification
1609			 * necessary at the socket layer so from our point of
1610			 * view it is safe to turn these checks off (and less
1611			 * work), however, the CIPSO draft says we should do
1612			 * all the CIPSO validations here but it doesn't
1613			 * really specify _exactly_ what we need to validate
1614			 * ... so, just make it a sysctl tunable. */
1615			if (cipso_v4_rbm_strictvalid) {
1616				if (cipso_v4_map_lvl_valid(doi_def,
1617							   tag[3]) < 0) {
1618					err_offset = opt_iter + 3;
1619					goto validate_return_locked;
1620				}
1621				if (tag_len > CIPSO_V4_TAG_RBM_BLEN &&
1622				    cipso_v4_map_cat_rbm_valid(doi_def,
1623							    &tag[4],
1624							    tag_len - 4) < 0) {
1625					err_offset = opt_iter + 4;
1626					goto validate_return_locked;
1627				}
1628			}
1629			break;
1630		case CIPSO_V4_TAG_ENUM:
1631			if (tag_len < CIPSO_V4_TAG_ENUM_BLEN) {
1632				err_offset = opt_iter + 1;
1633				goto validate_return_locked;
1634			}
1635
1636			if (cipso_v4_map_lvl_valid(doi_def,
1637						   tag[3]) < 0) {
1638				err_offset = opt_iter + 3;
1639				goto validate_return_locked;
1640			}
1641			if (tag_len > CIPSO_V4_TAG_ENUM_BLEN &&
1642			    cipso_v4_map_cat_enum_valid(doi_def,
1643							&tag[4],
1644							tag_len - 4) < 0) {
1645				err_offset = opt_iter + 4;
1646				goto validate_return_locked;
1647			}
1648			break;
1649		case CIPSO_V4_TAG_RANGE:
1650			if (tag_len < CIPSO_V4_TAG_RNG_BLEN) {
1651				err_offset = opt_iter + 1;
1652				goto validate_return_locked;
1653			}
1654
1655			if (cipso_v4_map_lvl_valid(doi_def,
1656						   tag[3]) < 0) {
1657				err_offset = opt_iter + 3;
1658				goto validate_return_locked;
1659			}
1660			if (tag_len > CIPSO_V4_TAG_RNG_BLEN &&
1661			    cipso_v4_map_cat_rng_valid(doi_def,
1662						       &tag[4],
1663						       tag_len - 4) < 0) {
1664				err_offset = opt_iter + 4;
1665				goto validate_return_locked;
1666			}
1667			break;
1668		case CIPSO_V4_TAG_LOCAL:
1669			/* This is a non-standard tag that we only allow for
1670			 * local connections, so if the incoming interface is
1671			 * not the loopback device drop the packet. Further,
1672			 * there is no legitimate reason for setting this from
1673			 * userspace so reject it if skb is NULL. */
1674			if (!skb || !(skb->dev->flags & IFF_LOOPBACK)) {
1675				err_offset = opt_iter;
1676				goto validate_return_locked;
1677			}
1678			if (tag_len != CIPSO_V4_TAG_LOC_BLEN) {
1679				err_offset = opt_iter + 1;
1680				goto validate_return_locked;
1681			}
1682			break;
1683		default:
1684			err_offset = opt_iter;
1685			goto validate_return_locked;
1686		}
1687
1688		tag += tag_len;
1689		opt_iter += tag_len;
1690	}
1691
1692validate_return_locked:
1693	rcu_read_unlock();
1694validate_return:
1695	*option = opt + err_offset;
1696	return err_offset;
1697}
1698
1699/**
1700 * cipso_v4_error - Send the correct response for a bad packet
1701 * @skb: the packet
1702 * @error: the error code
1703 * @gateway: CIPSO gateway flag
1704 *
1705 * Description:
1706 * Based on the error code given in @error, send an ICMP error message back to
1707 * the originating host.  From the IETF draft ...
1708 *
1709 *  "If the contents of the CIPSO [option] are valid but the security label is
1710 *   outside of the configured host or port label range, the datagram is
1711 *   discarded and an ICMP 'destination unreachable' (type 3) is generated and
1712 *   returned.  The code field of the ICMP is set to 'communication with
1713 *   destination network administratively prohibited' (code 9) or to
1714 *   'communication with destination host administratively prohibited'
1715 *   (code 10).  The value of the code is dependent on whether the originator
1716 *   of the ICMP message is acting as a CIPSO host or a CIPSO gateway.  The
1717 *   recipient of the ICMP message MUST be able to handle either value.  The
1718 *   same procedure is performed if a CIPSO [option] can not be added to an
1719 *   IP packet because it is too large to fit in the IP options area."
1720 *
1721 *  "If the error is triggered by receipt of an ICMP message, the message is
1722 *   discarded and no response is permitted (consistent with general ICMP
1723 *   processing rules)."
1724 *
1725 */
1726void cipso_v4_error(struct sk_buff *skb, int error, u32 gateway)
1727{
1728	unsigned char optbuf[sizeof(struct ip_options) + 40];
1729	struct ip_options *opt = (struct ip_options *)optbuf;
1730	int res;
1731
1732	if (ip_hdr(skb)->protocol == IPPROTO_ICMP || error != -EACCES)
1733		return;
1734
1735	/*
1736	 * We might be called above the IP layer,
1737	 * so we can not use icmp_send and IPCB here.
1738	 */
1739
1740	memset(opt, 0, sizeof(struct ip_options));
1741	opt->optlen = ip_hdr(skb)->ihl*4 - sizeof(struct iphdr);
1742	rcu_read_lock();
1743	res = __ip_options_compile(dev_net(skb->dev), opt, skb, NULL);
1744	rcu_read_unlock();
1745
1746	if (res)
1747		return;
1748
1749	if (gateway)
1750		__icmp_send(skb, ICMP_DEST_UNREACH, ICMP_NET_ANO, 0, opt);
1751	else
1752		__icmp_send(skb, ICMP_DEST_UNREACH, ICMP_HOST_ANO, 0, opt);
1753}
1754
1755/**
1756 * cipso_v4_genopt - Generate a CIPSO option
1757 * @buf: the option buffer
1758 * @buf_len: the size of opt_buf
1759 * @doi_def: the CIPSO DOI to use
1760 * @secattr: the security attributes
1761 *
1762 * Description:
1763 * Generate a CIPSO option using the DOI definition and security attributes
1764 * passed to the function.  Returns the length of the option on success and
1765 * negative values on failure.
1766 *
1767 */
1768static int cipso_v4_genopt(unsigned char *buf, u32 buf_len,
1769			   const struct cipso_v4_doi *doi_def,
1770			   const struct netlbl_lsm_secattr *secattr)
1771{
1772	int ret_val;
1773	u32 iter;
1774
1775	if (buf_len <= CIPSO_V4_HDR_LEN)
1776		return -ENOSPC;
1777
1778	/* XXX - This code assumes only one tag per CIPSO option which isn't
1779	 * really a good assumption to make but since we only support the MAC
1780	 * tags right now it is a safe assumption. */
1781	iter = 0;
1782	do {
1783		memset(buf, 0, buf_len);
1784		switch (doi_def->tags[iter]) {
1785		case CIPSO_V4_TAG_RBITMAP:
1786			ret_val = cipso_v4_gentag_rbm(doi_def,
1787						   secattr,
1788						   &buf[CIPSO_V4_HDR_LEN],
1789						   buf_len - CIPSO_V4_HDR_LEN);
1790			break;
1791		case CIPSO_V4_TAG_ENUM:
1792			ret_val = cipso_v4_gentag_enum(doi_def,
1793						   secattr,
1794						   &buf[CIPSO_V4_HDR_LEN],
1795						   buf_len - CIPSO_V4_HDR_LEN);
1796			break;
1797		case CIPSO_V4_TAG_RANGE:
1798			ret_val = cipso_v4_gentag_rng(doi_def,
1799						   secattr,
1800						   &buf[CIPSO_V4_HDR_LEN],
1801						   buf_len - CIPSO_V4_HDR_LEN);
1802			break;
1803		case CIPSO_V4_TAG_LOCAL:
1804			ret_val = cipso_v4_gentag_loc(doi_def,
1805						   secattr,
1806						   &buf[CIPSO_V4_HDR_LEN],
1807						   buf_len - CIPSO_V4_HDR_LEN);
1808			break;
1809		default:
1810			return -EPERM;
1811		}
1812
1813		iter++;
1814	} while (ret_val < 0 &&
1815		 iter < CIPSO_V4_TAG_MAXCNT &&
1816		 doi_def->tags[iter] != CIPSO_V4_TAG_INVALID);
1817	if (ret_val < 0)
1818		return ret_val;
1819	cipso_v4_gentag_hdr(doi_def, buf, ret_val);
1820	return CIPSO_V4_HDR_LEN + ret_val;
1821}
1822
1823/**
1824 * cipso_v4_sock_setattr - Add a CIPSO option to a socket
1825 * @sk: the socket
1826 * @doi_def: the CIPSO DOI to use
1827 * @secattr: the specific security attributes of the socket
1828 *
1829 * Description:
1830 * Set the CIPSO option on the given socket using the DOI definition and
1831 * security attributes passed to the function.  This function requires
1832 * exclusive access to @sk, which means it either needs to be in the
1833 * process of being created or locked.  Returns zero on success and negative
1834 * values on failure.
1835 *
1836 */
1837int cipso_v4_sock_setattr(struct sock *sk,
1838			  const struct cipso_v4_doi *doi_def,
1839			  const struct netlbl_lsm_secattr *secattr)
1840{
1841	int ret_val = -EPERM;
1842	unsigned char *buf = NULL;
1843	u32 buf_len;
1844	u32 opt_len;
1845	struct ip_options_rcu *old, *opt = NULL;
1846	struct inet_sock *sk_inet;
1847	struct inet_connection_sock *sk_conn;
1848
1849	/* In the case of sock_create_lite(), the sock->sk field is not
1850	 * defined yet but it is not a problem as the only users of these
1851	 * "lite" PF_INET sockets are functions which do an accept() call
1852	 * afterwards so we will label the socket as part of the accept(). */
1853	if (!sk)
1854		return 0;
1855
1856	/* We allocate the maximum CIPSO option size here so we are probably
1857	 * being a little wasteful, but it makes our life _much_ easier later
1858	 * on and after all we are only talking about 40 bytes. */
1859	buf_len = CIPSO_V4_OPT_LEN_MAX;
1860	buf = kmalloc(buf_len, GFP_ATOMIC);
1861	if (!buf) {
1862		ret_val = -ENOMEM;
1863		goto socket_setattr_failure;
1864	}
1865
1866	ret_val = cipso_v4_genopt(buf, buf_len, doi_def, secattr);
1867	if (ret_val < 0)
1868		goto socket_setattr_failure;
1869	buf_len = ret_val;
1870
1871	/* We can't use ip_options_get() directly because it makes a call to
1872	 * ip_options_get_alloc() which allocates memory with GFP_KERNEL and
1873	 * we won't always have CAP_NET_RAW even though we _always_ want to
1874	 * set the IPOPT_CIPSO option. */
1875	opt_len = (buf_len + 3) & ~3;
1876	opt = kzalloc(sizeof(*opt) + opt_len, GFP_ATOMIC);
1877	if (!opt) {
1878		ret_val = -ENOMEM;
1879		goto socket_setattr_failure;
1880	}
1881	memcpy(opt->opt.__data, buf, buf_len);
1882	opt->opt.optlen = opt_len;
1883	opt->opt.cipso = sizeof(struct iphdr);
1884	kfree(buf);
1885	buf = NULL;
1886
1887	sk_inet = inet_sk(sk);
1888
1889	old = rcu_dereference_protected(sk_inet->inet_opt,
1890					lockdep_sock_is_held(sk));
1891	if (sk_inet->is_icsk) {
1892		sk_conn = inet_csk(sk);
1893		if (old)
1894			sk_conn->icsk_ext_hdr_len -= old->opt.optlen;
1895		sk_conn->icsk_ext_hdr_len += opt->opt.optlen;
1896		sk_conn->icsk_sync_mss(sk, sk_conn->icsk_pmtu_cookie);
1897	}
1898	rcu_assign_pointer(sk_inet->inet_opt, opt);
1899	if (old)
1900		kfree_rcu(old, rcu);
1901
1902	return 0;
1903
1904socket_setattr_failure:
1905	kfree(buf);
1906	kfree(opt);
1907	return ret_val;
1908}
1909
1910/**
1911 * cipso_v4_req_setattr - Add a CIPSO option to a connection request socket
1912 * @req: the connection request socket
1913 * @doi_def: the CIPSO DOI to use
1914 * @secattr: the specific security attributes of the socket
1915 *
1916 * Description:
1917 * Set the CIPSO option on the given socket using the DOI definition and
1918 * security attributes passed to the function.  Returns zero on success and
1919 * negative values on failure.
1920 *
1921 */
1922int cipso_v4_req_setattr(struct request_sock *req,
1923			 const struct cipso_v4_doi *doi_def,
1924			 const struct netlbl_lsm_secattr *secattr)
1925{
1926	int ret_val = -EPERM;
1927	unsigned char *buf = NULL;
1928	u32 buf_len;
1929	u32 opt_len;
1930	struct ip_options_rcu *opt = NULL;
1931	struct inet_request_sock *req_inet;
1932
1933	/* We allocate the maximum CIPSO option size here so we are probably
1934	 * being a little wasteful, but it makes our life _much_ easier later
1935	 * on and after all we are only talking about 40 bytes. */
1936	buf_len = CIPSO_V4_OPT_LEN_MAX;
1937	buf = kmalloc(buf_len, GFP_ATOMIC);
1938	if (!buf) {
1939		ret_val = -ENOMEM;
1940		goto req_setattr_failure;
1941	}
1942
1943	ret_val = cipso_v4_genopt(buf, buf_len, doi_def, secattr);
1944	if (ret_val < 0)
1945		goto req_setattr_failure;
1946	buf_len = ret_val;
1947
1948	/* We can't use ip_options_get() directly because it makes a call to
1949	 * ip_options_get_alloc() which allocates memory with GFP_KERNEL and
1950	 * we won't always have CAP_NET_RAW even though we _always_ want to
1951	 * set the IPOPT_CIPSO option. */
1952	opt_len = (buf_len + 3) & ~3;
1953	opt = kzalloc(sizeof(*opt) + opt_len, GFP_ATOMIC);
1954	if (!opt) {
1955		ret_val = -ENOMEM;
1956		goto req_setattr_failure;
1957	}
1958	memcpy(opt->opt.__data, buf, buf_len);
1959	opt->opt.optlen = opt_len;
1960	opt->opt.cipso = sizeof(struct iphdr);
1961	kfree(buf);
1962	buf = NULL;
1963
1964	req_inet = inet_rsk(req);
1965	opt = xchg((__force struct ip_options_rcu **)&req_inet->ireq_opt, opt);
1966	if (opt)
1967		kfree_rcu(opt, rcu);
1968
1969	return 0;
1970
1971req_setattr_failure:
1972	kfree(buf);
1973	kfree(opt);
1974	return ret_val;
1975}
1976
1977/**
1978 * cipso_v4_delopt - Delete the CIPSO option from a set of IP options
1979 * @opt_ptr: IP option pointer
1980 *
1981 * Description:
1982 * Deletes the CIPSO IP option from a set of IP options and makes the necessary
1983 * adjustments to the IP option structure.  Returns zero on success, negative
1984 * values on failure.
1985 *
1986 */
1987static int cipso_v4_delopt(struct ip_options_rcu __rcu **opt_ptr)
1988{
1989	struct ip_options_rcu *opt = rcu_dereference_protected(*opt_ptr, 1);
1990	int hdr_delta = 0;
1991
1992	if (!opt || opt->opt.cipso == 0)
1993		return 0;
1994	if (opt->opt.srr || opt->opt.rr || opt->opt.ts || opt->opt.router_alert) {
1995		u8 cipso_len;
1996		u8 cipso_off;
1997		unsigned char *cipso_ptr;
1998		int iter;
1999		int optlen_new;
2000
2001		cipso_off = opt->opt.cipso - sizeof(struct iphdr);
2002		cipso_ptr = &opt->opt.__data[cipso_off];
2003		cipso_len = cipso_ptr[1];
2004
2005		if (opt->opt.srr > opt->opt.cipso)
2006			opt->opt.srr -= cipso_len;
2007		if (opt->opt.rr > opt->opt.cipso)
2008			opt->opt.rr -= cipso_len;
2009		if (opt->opt.ts > opt->opt.cipso)
2010			opt->opt.ts -= cipso_len;
2011		if (opt->opt.router_alert > opt->opt.cipso)
2012			opt->opt.router_alert -= cipso_len;
2013		opt->opt.cipso = 0;
2014
2015		memmove(cipso_ptr, cipso_ptr + cipso_len,
2016			opt->opt.optlen - cipso_off - cipso_len);
2017
2018		/* determining the new total option length is tricky because of
2019		 * the padding necessary, the only thing i can think to do at
2020		 * this point is walk the options one-by-one, skipping the
2021		 * padding at the end to determine the actual option size and
2022		 * from there we can determine the new total option length */
2023		iter = 0;
2024		optlen_new = 0;
2025		while (iter < opt->opt.optlen)
2026			if (opt->opt.__data[iter] != IPOPT_NOP) {
2027				iter += opt->opt.__data[iter + 1];
2028				optlen_new = iter;
2029			} else
2030				iter++;
2031		hdr_delta = opt->opt.optlen;
2032		opt->opt.optlen = (optlen_new + 3) & ~3;
2033		hdr_delta -= opt->opt.optlen;
2034	} else {
2035		/* only the cipso option was present on the socket so we can
2036		 * remove the entire option struct */
2037		*opt_ptr = NULL;
2038		hdr_delta = opt->opt.optlen;
2039		kfree_rcu(opt, rcu);
2040	}
2041
2042	return hdr_delta;
2043}
2044
2045/**
2046 * cipso_v4_sock_delattr - Delete the CIPSO option from a socket
2047 * @sk: the socket
2048 *
2049 * Description:
2050 * Removes the CIPSO option from a socket, if present.
2051 *
2052 */
2053void cipso_v4_sock_delattr(struct sock *sk)
2054{
2055	struct inet_sock *sk_inet;
2056	int hdr_delta;
2057
2058	sk_inet = inet_sk(sk);
2059
2060	hdr_delta = cipso_v4_delopt(&sk_inet->inet_opt);
2061	if (sk_inet->is_icsk && hdr_delta > 0) {
2062		struct inet_connection_sock *sk_conn = inet_csk(sk);
2063		sk_conn->icsk_ext_hdr_len -= hdr_delta;
2064		sk_conn->icsk_sync_mss(sk, sk_conn->icsk_pmtu_cookie);
2065	}
2066}
2067
2068/**
2069 * cipso_v4_req_delattr - Delete the CIPSO option from a request socket
2070 * @req: the request socket
2071 *
2072 * Description:
2073 * Removes the CIPSO option from a request socket, if present.
2074 *
2075 */
2076void cipso_v4_req_delattr(struct request_sock *req)
2077{
2078	cipso_v4_delopt(&inet_rsk(req)->ireq_opt);
2079}
2080
2081/**
2082 * cipso_v4_getattr - Helper function for the cipso_v4_*_getattr functions
2083 * @cipso: the CIPSO v4 option
2084 * @secattr: the security attributes
2085 *
2086 * Description:
2087 * Inspect @cipso and return the security attributes in @secattr.  Returns zero
2088 * on success and negative values on failure.
2089 *
2090 */
2091int cipso_v4_getattr(const unsigned char *cipso,
2092		     struct netlbl_lsm_secattr *secattr)
2093{
2094	int ret_val = -ENOMSG;
2095	u32 doi;
2096	struct cipso_v4_doi *doi_def;
2097
2098	if (cipso_v4_cache_check(cipso, cipso[1], secattr) == 0)
2099		return 0;
2100
2101	doi = get_unaligned_be32(&cipso[2]);
2102	rcu_read_lock();
2103	doi_def = cipso_v4_doi_search(doi);
2104	if (!doi_def)
2105		goto getattr_return;
2106	/* XXX - This code assumes only one tag per CIPSO option which isn't
2107	 * really a good assumption to make but since we only support the MAC
2108	 * tags right now it is a safe assumption. */
2109	switch (cipso[6]) {
2110	case CIPSO_V4_TAG_RBITMAP:
2111		ret_val = cipso_v4_parsetag_rbm(doi_def, &cipso[6], secattr);
2112		break;
2113	case CIPSO_V4_TAG_ENUM:
2114		ret_val = cipso_v4_parsetag_enum(doi_def, &cipso[6], secattr);
2115		break;
2116	case CIPSO_V4_TAG_RANGE:
2117		ret_val = cipso_v4_parsetag_rng(doi_def, &cipso[6], secattr);
2118		break;
2119	case CIPSO_V4_TAG_LOCAL:
2120		ret_val = cipso_v4_parsetag_loc(doi_def, &cipso[6], secattr);
2121		break;
2122	}
2123	if (ret_val == 0)
2124		secattr->type = NETLBL_NLTYPE_CIPSOV4;
2125
2126getattr_return:
2127	rcu_read_unlock();
2128	return ret_val;
2129}
2130
2131/**
2132 * cipso_v4_sock_getattr - Get the security attributes from a sock
2133 * @sk: the sock
2134 * @secattr: the security attributes
2135 *
2136 * Description:
2137 * Query @sk to see if there is a CIPSO option attached to the sock and if
2138 * there is return the CIPSO security attributes in @secattr.  This function
2139 * requires that @sk be locked, or privately held, but it does not do any
2140 * locking itself.  Returns zero on success and negative values on failure.
2141 *
2142 */
2143int cipso_v4_sock_getattr(struct sock *sk, struct netlbl_lsm_secattr *secattr)
2144{
2145	struct ip_options_rcu *opt;
2146	int res = -ENOMSG;
2147
2148	rcu_read_lock();
2149	opt = rcu_dereference(inet_sk(sk)->inet_opt);
2150	if (opt && opt->opt.cipso)
2151		res = cipso_v4_getattr(opt->opt.__data +
2152						opt->opt.cipso -
2153						sizeof(struct iphdr),
2154				       secattr);
2155	rcu_read_unlock();
2156	return res;
2157}
2158
2159/**
2160 * cipso_v4_skbuff_setattr - Set the CIPSO option on a packet
2161 * @skb: the packet
2162 * @doi_def: the DOI structure
2163 * @secattr: the security attributes
2164 *
2165 * Description:
2166 * Set the CIPSO option on the given packet based on the security attributes.
2167 * Returns a pointer to the IP header on success and NULL on failure.
2168 *
2169 */
2170int cipso_v4_skbuff_setattr(struct sk_buff *skb,
2171			    const struct cipso_v4_doi *doi_def,
2172			    const struct netlbl_lsm_secattr *secattr)
2173{
2174	int ret_val;
2175	struct iphdr *iph;
2176	struct ip_options *opt = &IPCB(skb)->opt;
2177	unsigned char buf[CIPSO_V4_OPT_LEN_MAX];
2178	u32 buf_len = CIPSO_V4_OPT_LEN_MAX;
2179	u32 opt_len;
2180	int len_delta;
2181
2182	ret_val = cipso_v4_genopt(buf, buf_len, doi_def, secattr);
2183	if (ret_val < 0)
2184		return ret_val;
2185	buf_len = ret_val;
2186	opt_len = (buf_len + 3) & ~3;
2187
2188	/* we overwrite any existing options to ensure that we have enough
2189	 * room for the CIPSO option, the reason is that we _need_ to guarantee
2190	 * that the security label is applied to the packet - we do the same
2191	 * thing when using the socket options and it hasn't caused a problem,
2192	 * if we need to we can always revisit this choice later */
2193
2194	len_delta = opt_len - opt->optlen;
2195	/* if we don't ensure enough headroom we could panic on the skb_push()
2196	 * call below so make sure we have enough, we are also "mangling" the
2197	 * packet so we should probably do a copy-on-write call anyway */
2198	ret_val = skb_cow(skb, skb_headroom(skb) + len_delta);
2199	if (ret_val < 0)
2200		return ret_val;
2201
2202	if (len_delta > 0) {
2203		/* we assume that the header + opt->optlen have already been
2204		 * "pushed" in ip_options_build() or similar */
2205		iph = ip_hdr(skb);
2206		skb_push(skb, len_delta);
2207		memmove((char *)iph - len_delta, iph, iph->ihl << 2);
2208		skb_reset_network_header(skb);
2209		iph = ip_hdr(skb);
2210	} else if (len_delta < 0) {
2211		iph = ip_hdr(skb);
2212		memset(iph + 1, IPOPT_NOP, opt->optlen);
2213	} else
2214		iph = ip_hdr(skb);
2215
2216	if (opt->optlen > 0)
2217		memset(opt, 0, sizeof(*opt));
2218	opt->optlen = opt_len;
2219	opt->cipso = sizeof(struct iphdr);
2220	opt->is_changed = 1;
2221
2222	/* we have to do the following because we are being called from a
2223	 * netfilter hook which means the packet already has had the header
2224	 * fields populated and the checksum calculated - yes this means we
2225	 * are doing more work than needed but we do it to keep the core
2226	 * stack clean and tidy */
2227	memcpy(iph + 1, buf, buf_len);
2228	if (opt_len > buf_len)
2229		memset((char *)(iph + 1) + buf_len, 0, opt_len - buf_len);
2230	if (len_delta != 0) {
2231		iph->ihl = 5 + (opt_len >> 2);
2232		iph->tot_len = htons(skb->len);
2233	}
2234	ip_send_check(iph);
2235
2236	return 0;
2237}
2238
2239/**
2240 * cipso_v4_skbuff_delattr - Delete any CIPSO options from a packet
2241 * @skb: the packet
2242 *
2243 * Description:
2244 * Removes any and all CIPSO options from the given packet.  Returns zero on
2245 * success, negative values on failure.
2246 *
2247 */
2248int cipso_v4_skbuff_delattr(struct sk_buff *skb)
2249{
2250	int ret_val;
2251	struct iphdr *iph;
2252	struct ip_options *opt = &IPCB(skb)->opt;
2253	unsigned char *cipso_ptr;
2254
2255	if (opt->cipso == 0)
2256		return 0;
2257
2258	/* since we are changing the packet we should make a copy */
2259	ret_val = skb_cow(skb, skb_headroom(skb));
2260	if (ret_val < 0)
2261		return ret_val;
2262
2263	/* the easiest thing to do is just replace the cipso option with noop
2264	 * options since we don't change the size of the packet, although we
2265	 * still need to recalculate the checksum */
2266
2267	iph = ip_hdr(skb);
2268	cipso_ptr = (unsigned char *)iph + opt->cipso;
2269	memset(cipso_ptr, IPOPT_NOOP, cipso_ptr[1]);
2270	opt->cipso = 0;
2271	opt->is_changed = 1;
2272
2273	ip_send_check(iph);
2274
2275	return 0;
2276}
2277
2278/*
2279 * Setup Functions
2280 */
2281
2282/**
2283 * cipso_v4_init - Initialize the CIPSO module
2284 *
2285 * Description:
2286 * Initialize the CIPSO module and prepare it for use.  Returns zero on success
2287 * and negative values on failure.
2288 *
2289 */
2290static int __init cipso_v4_init(void)
2291{
2292	int ret_val;
2293
2294	ret_val = cipso_v4_cache_init();
2295	if (ret_val != 0)
2296		panic("Failed to initialize the CIPSO/IPv4 cache (%d)\n",
2297		      ret_val);
2298
2299	return 0;
2300}
2301
2302subsys_initcall(cipso_v4_init);