1 /* 2 * CIPSO - Commercial IP Security Option 3 * 4 * This is an implementation of the CIPSO 2.2 protocol as specified in 5 * draft-ietf-cipso-ipsecurity-01.txt with additional tag types as found in 6 * FIPS-188, copies of both documents can be found in the Documentation 7 * directory. 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 * Author: Paul Moore <paul.moore@hp.com> 12 * 13 */ 14 15 /* 16 * (c) Copyright Hewlett-Packard Development Company, L.P., 2006, 2008 17 * 18 * This program is free software; you can redistribute it and/or modify 19 * it under the terms of the GNU General Public License as published by 20 * the Free Software Foundation; either version 2 of the License, or 21 * (at your option) any later version. 22 * 23 * This program is distributed in the hope that it will be useful, 24 * but WITHOUT ANY WARRANTY; without even the implied warranty of 25 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See 26 * the GNU General Public License for more details. 27 * 28 * You should have received a copy of the GNU General Public License 29 * along with this program; if not, write to the Free Software 30 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA 31 * 32 */ 33 34 #include <linux/init.h> 35 #include <linux/types.h> 36 #include <linux/rcupdate.h> 37 #include <linux/list.h> 38 #include <linux/spinlock.h> 39 #include <linux/string.h> 40 #include <linux/jhash.h> 41 #include <net/ip.h> 42 #include <net/icmp.h> 43 #include <net/tcp.h> 44 #include <net/netlabel.h> 45 #include <net/cipso_ipv4.h> 46 #include <asm/atomic.h> 47 #include <asm/bug.h> 48 #include <asm/unaligned.h> 49 50 /* List of available DOI definitions */ 51 /* XXX - This currently assumes a minimal number of different DOIs in use, 52 * if in practice there are a lot of different DOIs this list should 53 * probably be turned into a hash table or something similar so we 54 * can do quick lookups. */ 55 static DEFINE_SPINLOCK(cipso_v4_doi_list_lock); 56 static LIST_HEAD(cipso_v4_doi_list); 57 58 /* Label mapping cache */ 59 int cipso_v4_cache_enabled = 1; 60 int cipso_v4_cache_bucketsize = 10; 61 #define CIPSO_V4_CACHE_BUCKETBITS 7 62 #define CIPSO_V4_CACHE_BUCKETS (1 << CIPSO_V4_CACHE_BUCKETBITS) 63 #define CIPSO_V4_CACHE_REORDERLIMIT 10 64 struct cipso_v4_map_cache_bkt { 65 spinlock_t lock; 66 u32 size; 67 struct list_head list; 68 }; 69 struct cipso_v4_map_cache_entry { 70 u32 hash; 71 unsigned char *key; 72 size_t key_len; 73 74 struct netlbl_lsm_cache *lsm_data; 75 76 u32 activity; 77 struct list_head list; 78 }; 79 static struct cipso_v4_map_cache_bkt *cipso_v4_cache = NULL; 80 81 /* Restricted bitmap (tag #1) flags */ 82 int cipso_v4_rbm_optfmt = 0; 83 int cipso_v4_rbm_strictvalid = 1; 84 85 /* 86 * Protocol Constants 87 */ 88 89 /* Maximum size of the CIPSO IP option, derived from the fact that the maximum 90 * IPv4 header size is 60 bytes and the base IPv4 header is 20 bytes long. */ 91 #define CIPSO_V4_OPT_LEN_MAX 40 92 93 /* Length of the base CIPSO option, this includes the option type (1 byte), the 94 * option length (1 byte), and the DOI (4 bytes). */ 95 #define CIPSO_V4_HDR_LEN 6 96 97 /* Base length of the restrictive category bitmap tag (tag #1). */ 98 #define CIPSO_V4_TAG_RBM_BLEN 4 99 100 /* Base length of the enumerated category tag (tag #2). */ 101 #define CIPSO_V4_TAG_ENUM_BLEN 4 102 103 /* Base length of the ranged categories bitmap tag (tag #5). */ 104 #define CIPSO_V4_TAG_RNG_BLEN 4 105 /* The maximum number of category ranges permitted in the ranged category tag 106 * (tag #5). You may note that the IETF draft states that the maximum number 107 * of category ranges is 7, but if the low end of the last category range is 108 * zero then it is possibile to fit 8 category ranges because the zero should 109 * be omitted. */ 110 #define CIPSO_V4_TAG_RNG_CAT_MAX 8 111 112 /* Base length of the local tag (non-standard tag). 113 * Tag definition (may change between kernel versions) 114 * 115 * 0 8 16 24 32 116 * +----------+----------+----------+----------+ 117 * | 10000000 | 00000110 | 32-bit secid value | 118 * +----------+----------+----------+----------+ 119 * | in (host byte order)| 120 * +----------+----------+ 121 * 122 */ 123 #define CIPSO_V4_TAG_LOC_BLEN 6 124 125 /* 126 * Helper Functions 127 */ 128 129 /** 130 * cipso_v4_bitmap_walk - Walk a bitmap looking for a bit 131 * @bitmap: the bitmap 132 * @bitmap_len: length in bits 133 * @offset: starting offset 134 * @state: if non-zero, look for a set (1) bit else look for a cleared (0) bit 135 * 136 * Description: 137 * Starting at @offset, walk the bitmap from left to right until either the 138 * desired bit is found or we reach the end. Return the bit offset, -1 if 139 * not found, or -2 if error. 140 */ 141 static int cipso_v4_bitmap_walk(const unsigned char *bitmap, 142 u32 bitmap_len, 143 u32 offset, 144 u8 state) 145 { 146 u32 bit_spot; 147 u32 byte_offset; 148 unsigned char bitmask; 149 unsigned char byte; 150 151 /* gcc always rounds to zero when doing integer division */ 152 byte_offset = offset / 8; 153 byte = bitmap[byte_offset]; 154 bit_spot = offset; 155 bitmask = 0x80 >> (offset % 8); 156 157 while (bit_spot < bitmap_len) { 158 if ((state && (byte & bitmask) == bitmask) || 159 (state == 0 && (byte & bitmask) == 0)) 160 return bit_spot; 161 162 bit_spot++; 163 bitmask >>= 1; 164 if (bitmask == 0) { 165 byte = bitmap[++byte_offset]; 166 bitmask = 0x80; 167 } 168 } 169 170 return -1; 171 } 172 173 /** 174 * cipso_v4_bitmap_setbit - Sets a single bit in a bitmap 175 * @bitmap: the bitmap 176 * @bit: the bit 177 * @state: if non-zero, set the bit (1) else clear the bit (0) 178 * 179 * Description: 180 * Set a single bit in the bitmask. Returns zero on success, negative values 181 * on error. 182 */ 183 static void cipso_v4_bitmap_setbit(unsigned char *bitmap, 184 u32 bit, 185 u8 state) 186 { 187 u32 byte_spot; 188 u8 bitmask; 189 190 /* gcc always rounds to zero when doing integer division */ 191 byte_spot = bit / 8; 192 bitmask = 0x80 >> (bit % 8); 193 if (state) 194 bitmap[byte_spot] |= bitmask; 195 else 196 bitmap[byte_spot] &= ~bitmask; 197 } 198 199 /** 200 * cipso_v4_cache_entry_free - Frees a cache entry 201 * @entry: the entry to free 202 * 203 * Description: 204 * This function frees the memory associated with a cache entry including the 205 * LSM cache data if there are no longer any users, i.e. reference count == 0. 206 * 207 */ 208 static void cipso_v4_cache_entry_free(struct cipso_v4_map_cache_entry *entry) 209 { 210 if (entry->lsm_data) 211 netlbl_secattr_cache_free(entry->lsm_data); 212 kfree(entry->key); 213 kfree(entry); 214 } 215 216 /** 217 * cipso_v4_map_cache_hash - Hashing function for the CIPSO cache 218 * @key: the hash key 219 * @key_len: the length of the key in bytes 220 * 221 * Description: 222 * The CIPSO tag hashing function. Returns a 32-bit hash value. 223 * 224 */ 225 static u32 cipso_v4_map_cache_hash(const unsigned char *key, u32 key_len) 226 { 227 return jhash(key, key_len, 0); 228 } 229 230 /* 231 * Label Mapping Cache Functions 232 */ 233 234 /** 235 * cipso_v4_cache_init - Initialize the CIPSO cache 236 * 237 * Description: 238 * Initializes the CIPSO label mapping cache, this function should be called 239 * before any of the other functions defined in this file. Returns zero on 240 * success, negative values on error. 241 * 242 */ 243 static int cipso_v4_cache_init(void) 244 { 245 u32 iter; 246 247 cipso_v4_cache = kcalloc(CIPSO_V4_CACHE_BUCKETS, 248 sizeof(struct cipso_v4_map_cache_bkt), 249 GFP_KERNEL); 250 if (cipso_v4_cache == NULL) 251 return -ENOMEM; 252 253 for (iter = 0; iter < CIPSO_V4_CACHE_BUCKETS; iter++) { 254 spin_lock_init(&cipso_v4_cache[iter].lock); 255 cipso_v4_cache[iter].size = 0; 256 INIT_LIST_HEAD(&cipso_v4_cache[iter].list); 257 } 258 259 return 0; 260 } 261 262 /** 263 * cipso_v4_cache_invalidate - Invalidates the current CIPSO cache 264 * 265 * Description: 266 * Invalidates and frees any entries in the CIPSO cache. Returns zero on 267 * success and negative values on failure. 268 * 269 */ 270 void cipso_v4_cache_invalidate(void) 271 { 272 struct cipso_v4_map_cache_entry *entry, *tmp_entry; 273 u32 iter; 274 275 for (iter = 0; iter < CIPSO_V4_CACHE_BUCKETS; iter++) { 276 spin_lock_bh(&cipso_v4_cache[iter].lock); 277 list_for_each_entry_safe(entry, 278 tmp_entry, 279 &cipso_v4_cache[iter].list, list) { 280 list_del(&entry->list); 281 cipso_v4_cache_entry_free(entry); 282 } 283 cipso_v4_cache[iter].size = 0; 284 spin_unlock_bh(&cipso_v4_cache[iter].lock); 285 } 286 287 return; 288 } 289 290 /** 291 * cipso_v4_cache_check - Check the CIPSO cache for a label mapping 292 * @key: the buffer to check 293 * @key_len: buffer length in bytes 294 * @secattr: the security attribute struct to use 295 * 296 * Description: 297 * This function checks the cache to see if a label mapping already exists for 298 * the given key. If there is a match then the cache is adjusted and the 299 * @secattr struct is populated with the correct LSM security attributes. The 300 * cache is adjusted in the following manner if the entry is not already the 301 * first in the cache bucket: 302 * 303 * 1. The cache entry's activity counter is incremented 304 * 2. The previous (higher ranking) entry's activity counter is decremented 305 * 3. If the difference between the two activity counters is geater than 306 * CIPSO_V4_CACHE_REORDERLIMIT the two entries are swapped 307 * 308 * Returns zero on success, -ENOENT for a cache miss, and other negative values 309 * on error. 310 * 311 */ 312 static int cipso_v4_cache_check(const unsigned char *key, 313 u32 key_len, 314 struct netlbl_lsm_secattr *secattr) 315 { 316 u32 bkt; 317 struct cipso_v4_map_cache_entry *entry; 318 struct cipso_v4_map_cache_entry *prev_entry = NULL; 319 u32 hash; 320 321 if (!cipso_v4_cache_enabled) 322 return -ENOENT; 323 324 hash = cipso_v4_map_cache_hash(key, key_len); 325 bkt = hash & (CIPSO_V4_CACHE_BUCKETS - 1); 326 spin_lock_bh(&cipso_v4_cache[bkt].lock); 327 list_for_each_entry(entry, &cipso_v4_cache[bkt].list, list) { 328 if (entry->hash == hash && 329 entry->key_len == key_len && 330 memcmp(entry->key, key, key_len) == 0) { 331 entry->activity += 1; 332 atomic_inc(&entry->lsm_data->refcount); 333 secattr->cache = entry->lsm_data; 334 secattr->flags |= NETLBL_SECATTR_CACHE; 335 secattr->type = NETLBL_NLTYPE_CIPSOV4; 336 if (prev_entry == NULL) { 337 spin_unlock_bh(&cipso_v4_cache[bkt].lock); 338 return 0; 339 } 340 341 if (prev_entry->activity > 0) 342 prev_entry->activity -= 1; 343 if (entry->activity > prev_entry->activity && 344 entry->activity - prev_entry->activity > 345 CIPSO_V4_CACHE_REORDERLIMIT) { 346 __list_del(entry->list.prev, entry->list.next); 347 __list_add(&entry->list, 348 prev_entry->list.prev, 349 &prev_entry->list); 350 } 351 352 spin_unlock_bh(&cipso_v4_cache[bkt].lock); 353 return 0; 354 } 355 prev_entry = entry; 356 } 357 spin_unlock_bh(&cipso_v4_cache[bkt].lock); 358 359 return -ENOENT; 360 } 361 362 /** 363 * cipso_v4_cache_add - Add an entry to the CIPSO cache 364 * @skb: the packet 365 * @secattr: the packet's security attributes 366 * 367 * Description: 368 * Add a new entry into the CIPSO label mapping cache. Add the new entry to 369 * head of the cache bucket's list, if the cache bucket is out of room remove 370 * the last entry in the list first. It is important to note that there is 371 * currently no checking for duplicate keys. Returns zero on success, 372 * negative values on failure. 373 * 374 */ 375 int cipso_v4_cache_add(const struct sk_buff *skb, 376 const struct netlbl_lsm_secattr *secattr) 377 { 378 int ret_val = -EPERM; 379 u32 bkt; 380 struct cipso_v4_map_cache_entry *entry = NULL; 381 struct cipso_v4_map_cache_entry *old_entry = NULL; 382 unsigned char *cipso_ptr; 383 u32 cipso_ptr_len; 384 385 if (!cipso_v4_cache_enabled || cipso_v4_cache_bucketsize <= 0) 386 return 0; 387 388 cipso_ptr = CIPSO_V4_OPTPTR(skb); 389 cipso_ptr_len = cipso_ptr[1]; 390 391 entry = kzalloc(sizeof(*entry), GFP_ATOMIC); 392 if (entry == NULL) 393 return -ENOMEM; 394 entry->key = kmemdup(cipso_ptr, cipso_ptr_len, GFP_ATOMIC); 395 if (entry->key == NULL) { 396 ret_val = -ENOMEM; 397 goto cache_add_failure; 398 } 399 entry->key_len = cipso_ptr_len; 400 entry->hash = cipso_v4_map_cache_hash(cipso_ptr, cipso_ptr_len); 401 atomic_inc(&secattr->cache->refcount); 402 entry->lsm_data = secattr->cache; 403 404 bkt = entry->hash & (CIPSO_V4_CACHE_BUCKETS - 1); 405 spin_lock_bh(&cipso_v4_cache[bkt].lock); 406 if (cipso_v4_cache[bkt].size < cipso_v4_cache_bucketsize) { 407 list_add(&entry->list, &cipso_v4_cache[bkt].list); 408 cipso_v4_cache[bkt].size += 1; 409 } else { 410 old_entry = list_entry(cipso_v4_cache[bkt].list.prev, 411 struct cipso_v4_map_cache_entry, list); 412 list_del(&old_entry->list); 413 list_add(&entry->list, &cipso_v4_cache[bkt].list); 414 cipso_v4_cache_entry_free(old_entry); 415 } 416 spin_unlock_bh(&cipso_v4_cache[bkt].lock); 417 418 return 0; 419 420 cache_add_failure: 421 if (entry) 422 cipso_v4_cache_entry_free(entry); 423 return ret_val; 424 } 425 426 /* 427 * DOI List Functions 428 */ 429 430 /** 431 * cipso_v4_doi_search - Searches for a DOI definition 432 * @doi: the DOI to search for 433 * 434 * Description: 435 * Search the DOI definition list for a DOI definition with a DOI value that 436 * matches @doi. The caller is responsibile for calling rcu_read_[un]lock(). 437 * Returns a pointer to the DOI definition on success and NULL on failure. 438 */ 439 static struct cipso_v4_doi *cipso_v4_doi_search(u32 doi) 440 { 441 struct cipso_v4_doi *iter; 442 443 list_for_each_entry_rcu(iter, &cipso_v4_doi_list, list) 444 if (iter->doi == doi && atomic_read(&iter->refcount)) 445 return iter; 446 return NULL; 447 } 448 449 /** 450 * cipso_v4_doi_add - Add a new DOI to the CIPSO protocol engine 451 * @doi_def: the DOI structure 452 * 453 * Description: 454 * The caller defines a new DOI for use by the CIPSO engine and calls this 455 * function to add it to the list of acceptable domains. The caller must 456 * ensure that the mapping table specified in @doi_def->map meets all of the 457 * requirements of the mapping type (see cipso_ipv4.h for details). Returns 458 * zero on success and non-zero on failure. 459 * 460 */ 461 int cipso_v4_doi_add(struct cipso_v4_doi *doi_def) 462 { 463 u32 iter; 464 465 if (doi_def == NULL || doi_def->doi == CIPSO_V4_DOI_UNKNOWN) 466 return -EINVAL; 467 for (iter = 0; iter < CIPSO_V4_TAG_MAXCNT; iter++) { 468 switch (doi_def->tags[iter]) { 469 case CIPSO_V4_TAG_RBITMAP: 470 break; 471 case CIPSO_V4_TAG_RANGE: 472 if (doi_def->type != CIPSO_V4_MAP_PASS) 473 return -EINVAL; 474 break; 475 case CIPSO_V4_TAG_INVALID: 476 if (iter == 0) 477 return -EINVAL; 478 break; 479 case CIPSO_V4_TAG_ENUM: 480 if (doi_def->type != CIPSO_V4_MAP_PASS) 481 return -EINVAL; 482 break; 483 case CIPSO_V4_TAG_LOCAL: 484 if (doi_def->type != CIPSO_V4_MAP_LOCAL) 485 return -EINVAL; 486 break; 487 default: 488 return -EINVAL; 489 } 490 } 491 492 atomic_set(&doi_def->refcount, 1); 493 INIT_RCU_HEAD(&doi_def->rcu); 494 495 spin_lock(&cipso_v4_doi_list_lock); 496 if (cipso_v4_doi_search(doi_def->doi) != NULL) 497 goto doi_add_failure; 498 list_add_tail_rcu(&doi_def->list, &cipso_v4_doi_list); 499 spin_unlock(&cipso_v4_doi_list_lock); 500 501 return 0; 502 503 doi_add_failure: 504 spin_unlock(&cipso_v4_doi_list_lock); 505 return -EEXIST; 506 } 507 508 /** 509 * cipso_v4_doi_free - Frees a DOI definition 510 * @entry: the entry's RCU field 511 * 512 * Description: 513 * This function frees all of the memory associated with a DOI definition. 514 * 515 */ 516 void cipso_v4_doi_free(struct cipso_v4_doi *doi_def) 517 { 518 if (doi_def == NULL) 519 return; 520 521 switch (doi_def->type) { 522 case CIPSO_V4_MAP_TRANS: 523 kfree(doi_def->map.std->lvl.cipso); 524 kfree(doi_def->map.std->lvl.local); 525 kfree(doi_def->map.std->cat.cipso); 526 kfree(doi_def->map.std->cat.local); 527 break; 528 } 529 kfree(doi_def); 530 } 531 532 /** 533 * cipso_v4_doi_free_rcu - Frees a DOI definition via the RCU pointer 534 * @entry: the entry's RCU field 535 * 536 * Description: 537 * This function is designed to be used as a callback to the call_rcu() 538 * function so that the memory allocated to the DOI definition can be released 539 * safely. 540 * 541 */ 542 static void cipso_v4_doi_free_rcu(struct rcu_head *entry) 543 { 544 struct cipso_v4_doi *doi_def; 545 546 doi_def = container_of(entry, struct cipso_v4_doi, rcu); 547 cipso_v4_doi_free(doi_def); 548 } 549 550 /** 551 * cipso_v4_doi_remove - Remove an existing DOI from the CIPSO protocol engine 552 * @doi: the DOI value 553 * @audit_secid: the LSM secid to use in the audit message 554 * 555 * Description: 556 * Removes a DOI definition from the CIPSO engine. The NetLabel routines will 557 * be called to release their own LSM domain mappings as well as our own 558 * domain list. Returns zero on success and negative values on failure. 559 * 560 */ 561 int cipso_v4_doi_remove(u32 doi, struct netlbl_audit *audit_info) 562 { 563 struct cipso_v4_doi *doi_def; 564 565 spin_lock(&cipso_v4_doi_list_lock); 566 doi_def = cipso_v4_doi_search(doi); 567 if (doi_def == NULL) { 568 spin_unlock(&cipso_v4_doi_list_lock); 569 return -ENOENT; 570 } 571 if (!atomic_dec_and_test(&doi_def->refcount)) { 572 spin_unlock(&cipso_v4_doi_list_lock); 573 return -EBUSY; 574 } 575 list_del_rcu(&doi_def->list); 576 spin_unlock(&cipso_v4_doi_list_lock); 577 578 cipso_v4_cache_invalidate(); 579 call_rcu(&doi_def->rcu, cipso_v4_doi_free_rcu); 580 581 return 0; 582 } 583 584 /** 585 * cipso_v4_doi_getdef - Returns a reference to a valid DOI definition 586 * @doi: the DOI value 587 * 588 * Description: 589 * Searches for a valid DOI definition and if one is found it is returned to 590 * the caller. Otherwise NULL is returned. The caller must ensure that 591 * rcu_read_lock() is held while accessing the returned definition and the DOI 592 * definition reference count is decremented when the caller is done. 593 * 594 */ 595 struct cipso_v4_doi *cipso_v4_doi_getdef(u32 doi) 596 { 597 struct cipso_v4_doi *doi_def; 598 599 rcu_read_lock(); 600 doi_def = cipso_v4_doi_search(doi); 601 if (doi_def == NULL) 602 goto doi_getdef_return; 603 if (!atomic_inc_not_zero(&doi_def->refcount)) 604 doi_def = NULL; 605 606 doi_getdef_return: 607 rcu_read_unlock(); 608 return doi_def; 609 } 610 611 /** 612 * cipso_v4_doi_putdef - Releases a reference for the given DOI definition 613 * @doi_def: the DOI definition 614 * 615 * Description: 616 * Releases a DOI definition reference obtained from cipso_v4_doi_getdef(). 617 * 618 */ 619 void cipso_v4_doi_putdef(struct cipso_v4_doi *doi_def) 620 { 621 if (doi_def == NULL) 622 return; 623 624 if (!atomic_dec_and_test(&doi_def->refcount)) 625 return; 626 spin_lock(&cipso_v4_doi_list_lock); 627 list_del_rcu(&doi_def->list); 628 spin_unlock(&cipso_v4_doi_list_lock); 629 630 cipso_v4_cache_invalidate(); 631 call_rcu(&doi_def->rcu, cipso_v4_doi_free_rcu); 632 } 633 634 /** 635 * cipso_v4_doi_walk - Iterate through the DOI definitions 636 * @skip_cnt: skip past this number of DOI definitions, updated 637 * @callback: callback for each DOI definition 638 * @cb_arg: argument for the callback function 639 * 640 * Description: 641 * Iterate over the DOI definition list, skipping the first @skip_cnt entries. 642 * For each entry call @callback, if @callback returns a negative value stop 643 * 'walking' through the list and return. Updates the value in @skip_cnt upon 644 * return. Returns zero on success, negative values on failure. 645 * 646 */ 647 int cipso_v4_doi_walk(u32 *skip_cnt, 648 int (*callback) (struct cipso_v4_doi *doi_def, void *arg), 649 void *cb_arg) 650 { 651 int ret_val = -ENOENT; 652 u32 doi_cnt = 0; 653 struct cipso_v4_doi *iter_doi; 654 655 rcu_read_lock(); 656 list_for_each_entry_rcu(iter_doi, &cipso_v4_doi_list, list) 657 if (atomic_read(&iter_doi->refcount) > 0) { 658 if (doi_cnt++ < *skip_cnt) 659 continue; 660 ret_val = callback(iter_doi, cb_arg); 661 if (ret_val < 0) { 662 doi_cnt--; 663 goto doi_walk_return; 664 } 665 } 666 667 doi_walk_return: 668 rcu_read_unlock(); 669 *skip_cnt = doi_cnt; 670 return ret_val; 671 } 672 673 /* 674 * Label Mapping Functions 675 */ 676 677 /** 678 * cipso_v4_map_lvl_valid - Checks to see if the given level is understood 679 * @doi_def: the DOI definition 680 * @level: the level to check 681 * 682 * Description: 683 * Checks the given level against the given DOI definition and returns a 684 * negative value if the level does not have a valid mapping and a zero value 685 * if the level is defined by the DOI. 686 * 687 */ 688 static int cipso_v4_map_lvl_valid(const struct cipso_v4_doi *doi_def, u8 level) 689 { 690 switch (doi_def->type) { 691 case CIPSO_V4_MAP_PASS: 692 return 0; 693 case CIPSO_V4_MAP_TRANS: 694 if (doi_def->map.std->lvl.cipso[level] < CIPSO_V4_INV_LVL) 695 return 0; 696 break; 697 } 698 699 return -EFAULT; 700 } 701 702 /** 703 * cipso_v4_map_lvl_hton - Perform a level mapping from the host to the network 704 * @doi_def: the DOI definition 705 * @host_lvl: the host MLS level 706 * @net_lvl: the network/CIPSO MLS level 707 * 708 * Description: 709 * Perform a label mapping to translate a local MLS level to the correct 710 * CIPSO level using the given DOI definition. Returns zero on success, 711 * negative values otherwise. 712 * 713 */ 714 static int cipso_v4_map_lvl_hton(const struct cipso_v4_doi *doi_def, 715 u32 host_lvl, 716 u32 *net_lvl) 717 { 718 switch (doi_def->type) { 719 case CIPSO_V4_MAP_PASS: 720 *net_lvl = host_lvl; 721 return 0; 722 case CIPSO_V4_MAP_TRANS: 723 if (host_lvl < doi_def->map.std->lvl.local_size && 724 doi_def->map.std->lvl.local[host_lvl] < CIPSO_V4_INV_LVL) { 725 *net_lvl = doi_def->map.std->lvl.local[host_lvl]; 726 return 0; 727 } 728 return -EPERM; 729 } 730 731 return -EINVAL; 732 } 733 734 /** 735 * cipso_v4_map_lvl_ntoh - Perform a level mapping from the network to the host 736 * @doi_def: the DOI definition 737 * @net_lvl: the network/CIPSO MLS level 738 * @host_lvl: the host MLS level 739 * 740 * Description: 741 * Perform a label mapping to translate a CIPSO level to the correct local MLS 742 * level using the given DOI definition. Returns zero on success, negative 743 * values otherwise. 744 * 745 */ 746 static int cipso_v4_map_lvl_ntoh(const struct cipso_v4_doi *doi_def, 747 u32 net_lvl, 748 u32 *host_lvl) 749 { 750 struct cipso_v4_std_map_tbl *map_tbl; 751 752 switch (doi_def->type) { 753 case CIPSO_V4_MAP_PASS: 754 *host_lvl = net_lvl; 755 return 0; 756 case CIPSO_V4_MAP_TRANS: 757 map_tbl = doi_def->map.std; 758 if (net_lvl < map_tbl->lvl.cipso_size && 759 map_tbl->lvl.cipso[net_lvl] < CIPSO_V4_INV_LVL) { 760 *host_lvl = doi_def->map.std->lvl.cipso[net_lvl]; 761 return 0; 762 } 763 return -EPERM; 764 } 765 766 return -EINVAL; 767 } 768 769 /** 770 * cipso_v4_map_cat_rbm_valid - Checks to see if the category bitmap is valid 771 * @doi_def: the DOI definition 772 * @bitmap: category bitmap 773 * @bitmap_len: bitmap length in bytes 774 * 775 * Description: 776 * Checks the given category bitmap against the given DOI definition and 777 * returns a negative value if any of the categories in the bitmap do not have 778 * a valid mapping and a zero value if all of the categories are valid. 779 * 780 */ 781 static int cipso_v4_map_cat_rbm_valid(const struct cipso_v4_doi *doi_def, 782 const unsigned char *bitmap, 783 u32 bitmap_len) 784 { 785 int cat = -1; 786 u32 bitmap_len_bits = bitmap_len * 8; 787 u32 cipso_cat_size; 788 u32 *cipso_array; 789 790 switch (doi_def->type) { 791 case CIPSO_V4_MAP_PASS: 792 return 0; 793 case CIPSO_V4_MAP_TRANS: 794 cipso_cat_size = doi_def->map.std->cat.cipso_size; 795 cipso_array = doi_def->map.std->cat.cipso; 796 for (;;) { 797 cat = cipso_v4_bitmap_walk(bitmap, 798 bitmap_len_bits, 799 cat + 1, 800 1); 801 if (cat < 0) 802 break; 803 if (cat >= cipso_cat_size || 804 cipso_array[cat] >= CIPSO_V4_INV_CAT) 805 return -EFAULT; 806 } 807 808 if (cat == -1) 809 return 0; 810 break; 811 } 812 813 return -EFAULT; 814 } 815 816 /** 817 * cipso_v4_map_cat_rbm_hton - Perform a category mapping from host to network 818 * @doi_def: the DOI definition 819 * @secattr: the security attributes 820 * @net_cat: the zero'd out category bitmap in network/CIPSO format 821 * @net_cat_len: the length of the CIPSO bitmap in bytes 822 * 823 * Description: 824 * Perform a label mapping to translate a local MLS category bitmap to the 825 * correct CIPSO bitmap using the given DOI definition. Returns the minimum 826 * size in bytes of the network bitmap on success, negative values otherwise. 827 * 828 */ 829 static int cipso_v4_map_cat_rbm_hton(const struct cipso_v4_doi *doi_def, 830 const struct netlbl_lsm_secattr *secattr, 831 unsigned char *net_cat, 832 u32 net_cat_len) 833 { 834 int host_spot = -1; 835 u32 net_spot = CIPSO_V4_INV_CAT; 836 u32 net_spot_max = 0; 837 u32 net_clen_bits = net_cat_len * 8; 838 u32 host_cat_size = 0; 839 u32 *host_cat_array = NULL; 840 841 if (doi_def->type == CIPSO_V4_MAP_TRANS) { 842 host_cat_size = doi_def->map.std->cat.local_size; 843 host_cat_array = doi_def->map.std->cat.local; 844 } 845 846 for (;;) { 847 host_spot = netlbl_secattr_catmap_walk(secattr->attr.mls.cat, 848 host_spot + 1); 849 if (host_spot < 0) 850 break; 851 852 switch (doi_def->type) { 853 case CIPSO_V4_MAP_PASS: 854 net_spot = host_spot; 855 break; 856 case CIPSO_V4_MAP_TRANS: 857 if (host_spot >= host_cat_size) 858 return -EPERM; 859 net_spot = host_cat_array[host_spot]; 860 if (net_spot >= CIPSO_V4_INV_CAT) 861 return -EPERM; 862 break; 863 } 864 if (net_spot >= net_clen_bits) 865 return -ENOSPC; 866 cipso_v4_bitmap_setbit(net_cat, net_spot, 1); 867 868 if (net_spot > net_spot_max) 869 net_spot_max = net_spot; 870 } 871 872 if (++net_spot_max % 8) 873 return net_spot_max / 8 + 1; 874 return net_spot_max / 8; 875 } 876 877 /** 878 * cipso_v4_map_cat_rbm_ntoh - Perform a category mapping from network to host 879 * @doi_def: the DOI definition 880 * @net_cat: the category bitmap in network/CIPSO format 881 * @net_cat_len: the length of the CIPSO bitmap in bytes 882 * @secattr: the security attributes 883 * 884 * Description: 885 * Perform a label mapping to translate a CIPSO bitmap to the correct local 886 * MLS category bitmap using the given DOI definition. Returns zero on 887 * success, negative values on failure. 888 * 889 */ 890 static int cipso_v4_map_cat_rbm_ntoh(const struct cipso_v4_doi *doi_def, 891 const unsigned char *net_cat, 892 u32 net_cat_len, 893 struct netlbl_lsm_secattr *secattr) 894 { 895 int ret_val; 896 int net_spot = -1; 897 u32 host_spot = CIPSO_V4_INV_CAT; 898 u32 net_clen_bits = net_cat_len * 8; 899 u32 net_cat_size = 0; 900 u32 *net_cat_array = NULL; 901 902 if (doi_def->type == CIPSO_V4_MAP_TRANS) { 903 net_cat_size = doi_def->map.std->cat.cipso_size; 904 net_cat_array = doi_def->map.std->cat.cipso; 905 } 906 907 for (;;) { 908 net_spot = cipso_v4_bitmap_walk(net_cat, 909 net_clen_bits, 910 net_spot + 1, 911 1); 912 if (net_spot < 0) { 913 if (net_spot == -2) 914 return -EFAULT; 915 return 0; 916 } 917 918 switch (doi_def->type) { 919 case CIPSO_V4_MAP_PASS: 920 host_spot = net_spot; 921 break; 922 case CIPSO_V4_MAP_TRANS: 923 if (net_spot >= net_cat_size) 924 return -EPERM; 925 host_spot = net_cat_array[net_spot]; 926 if (host_spot >= CIPSO_V4_INV_CAT) 927 return -EPERM; 928 break; 929 } 930 ret_val = netlbl_secattr_catmap_setbit(secattr->attr.mls.cat, 931 host_spot, 932 GFP_ATOMIC); 933 if (ret_val != 0) 934 return ret_val; 935 } 936 937 return -EINVAL; 938 } 939 940 /** 941 * cipso_v4_map_cat_enum_valid - Checks to see if the categories are valid 942 * @doi_def: the DOI definition 943 * @enumcat: category list 944 * @enumcat_len: length of the category list in bytes 945 * 946 * Description: 947 * Checks the given categories against the given DOI definition and returns a 948 * negative value if any of the categories do not have a valid mapping and a 949 * zero value if all of the categories are valid. 950 * 951 */ 952 static int cipso_v4_map_cat_enum_valid(const struct cipso_v4_doi *doi_def, 953 const unsigned char *enumcat, 954 u32 enumcat_len) 955 { 956 u16 cat; 957 int cat_prev = -1; 958 u32 iter; 959 960 if (doi_def->type != CIPSO_V4_MAP_PASS || enumcat_len & 0x01) 961 return -EFAULT; 962 963 for (iter = 0; iter < enumcat_len; iter += 2) { 964 cat = get_unaligned_be16(&enumcat[iter]); 965 if (cat <= cat_prev) 966 return -EFAULT; 967 cat_prev = cat; 968 } 969 970 return 0; 971 } 972 973 /** 974 * cipso_v4_map_cat_enum_hton - Perform a category mapping from host to network 975 * @doi_def: the DOI definition 976 * @secattr: the security attributes 977 * @net_cat: the zero'd out category list in network/CIPSO format 978 * @net_cat_len: the length of the CIPSO category list in bytes 979 * 980 * Description: 981 * Perform a label mapping to translate a local MLS category bitmap to the 982 * correct CIPSO category list using the given DOI definition. Returns the 983 * size in bytes of the network category bitmap on success, negative values 984 * otherwise. 985 * 986 */ 987 static int cipso_v4_map_cat_enum_hton(const struct cipso_v4_doi *doi_def, 988 const struct netlbl_lsm_secattr *secattr, 989 unsigned char *net_cat, 990 u32 net_cat_len) 991 { 992 int cat = -1; 993 u32 cat_iter = 0; 994 995 for (;;) { 996 cat = netlbl_secattr_catmap_walk(secattr->attr.mls.cat, 997 cat + 1); 998 if (cat < 0) 999 break; 1000 if ((cat_iter + 2) > net_cat_len) 1001 return -ENOSPC; 1002 1003 *((__be16 *)&net_cat[cat_iter]) = htons(cat); 1004 cat_iter += 2; 1005 } 1006 1007 return cat_iter; 1008 } 1009 1010 /** 1011 * cipso_v4_map_cat_enum_ntoh - Perform a category mapping from network to host 1012 * @doi_def: the DOI definition 1013 * @net_cat: the category list in network/CIPSO format 1014 * @net_cat_len: the length of the CIPSO bitmap in bytes 1015 * @secattr: the security attributes 1016 * 1017 * Description: 1018 * Perform a label mapping to translate a CIPSO category list to the correct 1019 * local MLS category bitmap using the given DOI definition. Returns zero on 1020 * success, negative values on failure. 1021 * 1022 */ 1023 static int cipso_v4_map_cat_enum_ntoh(const struct cipso_v4_doi *doi_def, 1024 const unsigned char *net_cat, 1025 u32 net_cat_len, 1026 struct netlbl_lsm_secattr *secattr) 1027 { 1028 int ret_val; 1029 u32 iter; 1030 1031 for (iter = 0; iter < net_cat_len; iter += 2) { 1032 ret_val = netlbl_secattr_catmap_setbit(secattr->attr.mls.cat, 1033 get_unaligned_be16(&net_cat[iter]), 1034 GFP_ATOMIC); 1035 if (ret_val != 0) 1036 return ret_val; 1037 } 1038 1039 return 0; 1040 } 1041 1042 /** 1043 * cipso_v4_map_cat_rng_valid - Checks to see if the categories are valid 1044 * @doi_def: the DOI definition 1045 * @rngcat: category list 1046 * @rngcat_len: length of the category list in bytes 1047 * 1048 * Description: 1049 * Checks the given categories against the given DOI definition and returns a 1050 * negative value if any of the categories do not have a valid mapping and a 1051 * zero value if all of the categories are valid. 1052 * 1053 */ 1054 static int cipso_v4_map_cat_rng_valid(const struct cipso_v4_doi *doi_def, 1055 const unsigned char *rngcat, 1056 u32 rngcat_len) 1057 { 1058 u16 cat_high; 1059 u16 cat_low; 1060 u32 cat_prev = CIPSO_V4_MAX_REM_CATS + 1; 1061 u32 iter; 1062 1063 if (doi_def->type != CIPSO_V4_MAP_PASS || rngcat_len & 0x01) 1064 return -EFAULT; 1065 1066 for (iter = 0; iter < rngcat_len; iter += 4) { 1067 cat_high = get_unaligned_be16(&rngcat[iter]); 1068 if ((iter + 4) <= rngcat_len) 1069 cat_low = get_unaligned_be16(&rngcat[iter + 2]); 1070 else 1071 cat_low = 0; 1072 1073 if (cat_high > cat_prev) 1074 return -EFAULT; 1075 1076 cat_prev = cat_low; 1077 } 1078 1079 return 0; 1080 } 1081 1082 /** 1083 * cipso_v4_map_cat_rng_hton - Perform a category mapping from host to network 1084 * @doi_def: the DOI definition 1085 * @secattr: the security attributes 1086 * @net_cat: the zero'd out category list in network/CIPSO format 1087 * @net_cat_len: the length of the CIPSO category list in bytes 1088 * 1089 * Description: 1090 * Perform a label mapping to translate a local MLS category bitmap to the 1091 * correct CIPSO category list using the given DOI definition. Returns the 1092 * size in bytes of the network category bitmap on success, negative values 1093 * otherwise. 1094 * 1095 */ 1096 static int cipso_v4_map_cat_rng_hton(const struct cipso_v4_doi *doi_def, 1097 const struct netlbl_lsm_secattr *secattr, 1098 unsigned char *net_cat, 1099 u32 net_cat_len) 1100 { 1101 int iter = -1; 1102 u16 array[CIPSO_V4_TAG_RNG_CAT_MAX * 2]; 1103 u32 array_cnt = 0; 1104 u32 cat_size = 0; 1105 1106 /* make sure we don't overflow the 'array[]' variable */ 1107 if (net_cat_len > 1108 (CIPSO_V4_OPT_LEN_MAX - CIPSO_V4_HDR_LEN - CIPSO_V4_TAG_RNG_BLEN)) 1109 return -ENOSPC; 1110 1111 for (;;) { 1112 iter = netlbl_secattr_catmap_walk(secattr->attr.mls.cat, 1113 iter + 1); 1114 if (iter < 0) 1115 break; 1116 cat_size += (iter == 0 ? 0 : sizeof(u16)); 1117 if (cat_size > net_cat_len) 1118 return -ENOSPC; 1119 array[array_cnt++] = iter; 1120 1121 iter = netlbl_secattr_catmap_walk_rng(secattr->attr.mls.cat, 1122 iter); 1123 if (iter < 0) 1124 return -EFAULT; 1125 cat_size += sizeof(u16); 1126 if (cat_size > net_cat_len) 1127 return -ENOSPC; 1128 array[array_cnt++] = iter; 1129 } 1130 1131 for (iter = 0; array_cnt > 0;) { 1132 *((__be16 *)&net_cat[iter]) = htons(array[--array_cnt]); 1133 iter += 2; 1134 array_cnt--; 1135 if (array[array_cnt] != 0) { 1136 *((__be16 *)&net_cat[iter]) = htons(array[array_cnt]); 1137 iter += 2; 1138 } 1139 } 1140 1141 return cat_size; 1142 } 1143 1144 /** 1145 * cipso_v4_map_cat_rng_ntoh - Perform a category mapping from network to host 1146 * @doi_def: the DOI definition 1147 * @net_cat: the category list in network/CIPSO format 1148 * @net_cat_len: the length of the CIPSO bitmap in bytes 1149 * @secattr: the security attributes 1150 * 1151 * Description: 1152 * Perform a label mapping to translate a CIPSO category list to the correct 1153 * local MLS category bitmap using the given DOI definition. Returns zero on 1154 * success, negative values on failure. 1155 * 1156 */ 1157 static int cipso_v4_map_cat_rng_ntoh(const struct cipso_v4_doi *doi_def, 1158 const unsigned char *net_cat, 1159 u32 net_cat_len, 1160 struct netlbl_lsm_secattr *secattr) 1161 { 1162 int ret_val; 1163 u32 net_iter; 1164 u16 cat_low; 1165 u16 cat_high; 1166 1167 for (net_iter = 0; net_iter < net_cat_len; net_iter += 4) { 1168 cat_high = get_unaligned_be16(&net_cat[net_iter]); 1169 if ((net_iter + 4) <= net_cat_len) 1170 cat_low = get_unaligned_be16(&net_cat[net_iter + 2]); 1171 else 1172 cat_low = 0; 1173 1174 ret_val = netlbl_secattr_catmap_setrng(secattr->attr.mls.cat, 1175 cat_low, 1176 cat_high, 1177 GFP_ATOMIC); 1178 if (ret_val != 0) 1179 return ret_val; 1180 } 1181 1182 return 0; 1183 } 1184 1185 /* 1186 * Protocol Handling Functions 1187 */ 1188 1189 /** 1190 * cipso_v4_gentag_hdr - Generate a CIPSO option header 1191 * @doi_def: the DOI definition 1192 * @len: the total tag length in bytes, not including this header 1193 * @buf: the CIPSO option buffer 1194 * 1195 * Description: 1196 * Write a CIPSO header into the beginning of @buffer. 1197 * 1198 */ 1199 static void cipso_v4_gentag_hdr(const struct cipso_v4_doi *doi_def, 1200 unsigned char *buf, 1201 u32 len) 1202 { 1203 buf[0] = IPOPT_CIPSO; 1204 buf[1] = CIPSO_V4_HDR_LEN + len; 1205 *(__be32 *)&buf[2] = htonl(doi_def->doi); 1206 } 1207 1208 /** 1209 * cipso_v4_gentag_rbm - Generate a CIPSO restricted bitmap tag (type #1) 1210 * @doi_def: the DOI definition 1211 * @secattr: the security attributes 1212 * @buffer: the option buffer 1213 * @buffer_len: length of buffer in bytes 1214 * 1215 * Description: 1216 * Generate a CIPSO option using the restricted bitmap tag, tag type #1. The 1217 * actual buffer length may be larger than the indicated size due to 1218 * translation between host and network category bitmaps. Returns the size of 1219 * the tag on success, negative values on failure. 1220 * 1221 */ 1222 static int cipso_v4_gentag_rbm(const struct cipso_v4_doi *doi_def, 1223 const struct netlbl_lsm_secattr *secattr, 1224 unsigned char *buffer, 1225 u32 buffer_len) 1226 { 1227 int ret_val; 1228 u32 tag_len; 1229 u32 level; 1230 1231 if ((secattr->flags & NETLBL_SECATTR_MLS_LVL) == 0) 1232 return -EPERM; 1233 1234 ret_val = cipso_v4_map_lvl_hton(doi_def, 1235 secattr->attr.mls.lvl, 1236 &level); 1237 if (ret_val != 0) 1238 return ret_val; 1239 1240 if (secattr->flags & NETLBL_SECATTR_MLS_CAT) { 1241 ret_val = cipso_v4_map_cat_rbm_hton(doi_def, 1242 secattr, 1243 &buffer[4], 1244 buffer_len - 4); 1245 if (ret_val < 0) 1246 return ret_val; 1247 1248 /* This will send packets using the "optimized" format when 1249 * possibile as specified in section 3.4.2.6 of the 1250 * CIPSO draft. */ 1251 if (cipso_v4_rbm_optfmt && ret_val > 0 && ret_val <= 10) 1252 tag_len = 14; 1253 else 1254 tag_len = 4 + ret_val; 1255 } else 1256 tag_len = 4; 1257 1258 buffer[0] = CIPSO_V4_TAG_RBITMAP; 1259 buffer[1] = tag_len; 1260 buffer[3] = level; 1261 1262 return tag_len; 1263 } 1264 1265 /** 1266 * cipso_v4_parsetag_rbm - Parse a CIPSO restricted bitmap tag 1267 * @doi_def: the DOI definition 1268 * @tag: the CIPSO tag 1269 * @secattr: the security attributes 1270 * 1271 * Description: 1272 * Parse a CIPSO restricted bitmap tag (tag type #1) and return the security 1273 * attributes in @secattr. Return zero on success, negatives values on 1274 * failure. 1275 * 1276 */ 1277 static int cipso_v4_parsetag_rbm(const struct cipso_v4_doi *doi_def, 1278 const unsigned char *tag, 1279 struct netlbl_lsm_secattr *secattr) 1280 { 1281 int ret_val; 1282 u8 tag_len = tag[1]; 1283 u32 level; 1284 1285 ret_val = cipso_v4_map_lvl_ntoh(doi_def, tag[3], &level); 1286 if (ret_val != 0) 1287 return ret_val; 1288 secattr->attr.mls.lvl = level; 1289 secattr->flags |= NETLBL_SECATTR_MLS_LVL; 1290 1291 if (tag_len > 4) { 1292 secattr->attr.mls.cat = 1293 netlbl_secattr_catmap_alloc(GFP_ATOMIC); 1294 if (secattr->attr.mls.cat == NULL) 1295 return -ENOMEM; 1296 1297 ret_val = cipso_v4_map_cat_rbm_ntoh(doi_def, 1298 &tag[4], 1299 tag_len - 4, 1300 secattr); 1301 if (ret_val != 0) { 1302 netlbl_secattr_catmap_free(secattr->attr.mls.cat); 1303 return ret_val; 1304 } 1305 1306 secattr->flags |= NETLBL_SECATTR_MLS_CAT; 1307 } 1308 1309 return 0; 1310 } 1311 1312 /** 1313 * cipso_v4_gentag_enum - Generate a CIPSO enumerated tag (type #2) 1314 * @doi_def: the DOI definition 1315 * @secattr: the security attributes 1316 * @buffer: the option buffer 1317 * @buffer_len: length of buffer in bytes 1318 * 1319 * Description: 1320 * Generate a CIPSO option using the enumerated tag, tag type #2. Returns the 1321 * size of the tag on success, negative values on failure. 1322 * 1323 */ 1324 static int cipso_v4_gentag_enum(const struct cipso_v4_doi *doi_def, 1325 const struct netlbl_lsm_secattr *secattr, 1326 unsigned char *buffer, 1327 u32 buffer_len) 1328 { 1329 int ret_val; 1330 u32 tag_len; 1331 u32 level; 1332 1333 if (!(secattr->flags & NETLBL_SECATTR_MLS_LVL)) 1334 return -EPERM; 1335 1336 ret_val = cipso_v4_map_lvl_hton(doi_def, 1337 secattr->attr.mls.lvl, 1338 &level); 1339 if (ret_val != 0) 1340 return ret_val; 1341 1342 if (secattr->flags & NETLBL_SECATTR_MLS_CAT) { 1343 ret_val = cipso_v4_map_cat_enum_hton(doi_def, 1344 secattr, 1345 &buffer[4], 1346 buffer_len - 4); 1347 if (ret_val < 0) 1348 return ret_val; 1349 1350 tag_len = 4 + ret_val; 1351 } else 1352 tag_len = 4; 1353 1354 buffer[0] = CIPSO_V4_TAG_ENUM; 1355 buffer[1] = tag_len; 1356 buffer[3] = level; 1357 1358 return tag_len; 1359 } 1360 1361 /** 1362 * cipso_v4_parsetag_enum - Parse a CIPSO enumerated tag 1363 * @doi_def: the DOI definition 1364 * @tag: the CIPSO tag 1365 * @secattr: the security attributes 1366 * 1367 * Description: 1368 * Parse a CIPSO enumerated tag (tag type #2) and return the security 1369 * attributes in @secattr. Return zero on success, negatives values on 1370 * failure. 1371 * 1372 */ 1373 static int cipso_v4_parsetag_enum(const struct cipso_v4_doi *doi_def, 1374 const unsigned char *tag, 1375 struct netlbl_lsm_secattr *secattr) 1376 { 1377 int ret_val; 1378 u8 tag_len = tag[1]; 1379 u32 level; 1380 1381 ret_val = cipso_v4_map_lvl_ntoh(doi_def, tag[3], &level); 1382 if (ret_val != 0) 1383 return ret_val; 1384 secattr->attr.mls.lvl = level; 1385 secattr->flags |= NETLBL_SECATTR_MLS_LVL; 1386 1387 if (tag_len > 4) { 1388 secattr->attr.mls.cat = 1389 netlbl_secattr_catmap_alloc(GFP_ATOMIC); 1390 if (secattr->attr.mls.cat == NULL) 1391 return -ENOMEM; 1392 1393 ret_val = cipso_v4_map_cat_enum_ntoh(doi_def, 1394 &tag[4], 1395 tag_len - 4, 1396 secattr); 1397 if (ret_val != 0) { 1398 netlbl_secattr_catmap_free(secattr->attr.mls.cat); 1399 return ret_val; 1400 } 1401 1402 secattr->flags |= NETLBL_SECATTR_MLS_CAT; 1403 } 1404 1405 return 0; 1406 } 1407 1408 /** 1409 * cipso_v4_gentag_rng - Generate a CIPSO ranged tag (type #5) 1410 * @doi_def: the DOI definition 1411 * @secattr: the security attributes 1412 * @buffer: the option buffer 1413 * @buffer_len: length of buffer in bytes 1414 * 1415 * Description: 1416 * Generate a CIPSO option using the ranged tag, tag type #5. Returns the 1417 * size of the tag on success, negative values on failure. 1418 * 1419 */ 1420 static int cipso_v4_gentag_rng(const struct cipso_v4_doi *doi_def, 1421 const struct netlbl_lsm_secattr *secattr, 1422 unsigned char *buffer, 1423 u32 buffer_len) 1424 { 1425 int ret_val; 1426 u32 tag_len; 1427 u32 level; 1428 1429 if (!(secattr->flags & NETLBL_SECATTR_MLS_LVL)) 1430 return -EPERM; 1431 1432 ret_val = cipso_v4_map_lvl_hton(doi_def, 1433 secattr->attr.mls.lvl, 1434 &level); 1435 if (ret_val != 0) 1436 return ret_val; 1437 1438 if (secattr->flags & NETLBL_SECATTR_MLS_CAT) { 1439 ret_val = cipso_v4_map_cat_rng_hton(doi_def, 1440 secattr, 1441 &buffer[4], 1442 buffer_len - 4); 1443 if (ret_val < 0) 1444 return ret_val; 1445 1446 tag_len = 4 + ret_val; 1447 } else 1448 tag_len = 4; 1449 1450 buffer[0] = CIPSO_V4_TAG_RANGE; 1451 buffer[1] = tag_len; 1452 buffer[3] = level; 1453 1454 return tag_len; 1455 } 1456 1457 /** 1458 * cipso_v4_parsetag_rng - Parse a CIPSO ranged tag 1459 * @doi_def: the DOI definition 1460 * @tag: the CIPSO tag 1461 * @secattr: the security attributes 1462 * 1463 * Description: 1464 * Parse a CIPSO ranged tag (tag type #5) and return the security attributes 1465 * in @secattr. Return zero on success, negatives values on failure. 1466 * 1467 */ 1468 static int cipso_v4_parsetag_rng(const struct cipso_v4_doi *doi_def, 1469 const unsigned char *tag, 1470 struct netlbl_lsm_secattr *secattr) 1471 { 1472 int ret_val; 1473 u8 tag_len = tag[1]; 1474 u32 level; 1475 1476 ret_val = cipso_v4_map_lvl_ntoh(doi_def, tag[3], &level); 1477 if (ret_val != 0) 1478 return ret_val; 1479 secattr->attr.mls.lvl = level; 1480 secattr->flags |= NETLBL_SECATTR_MLS_LVL; 1481 1482 if (tag_len > 4) { 1483 secattr->attr.mls.cat = 1484 netlbl_secattr_catmap_alloc(GFP_ATOMIC); 1485 if (secattr->attr.mls.cat == NULL) 1486 return -ENOMEM; 1487 1488 ret_val = cipso_v4_map_cat_rng_ntoh(doi_def, 1489 &tag[4], 1490 tag_len - 4, 1491 secattr); 1492 if (ret_val != 0) { 1493 netlbl_secattr_catmap_free(secattr->attr.mls.cat); 1494 return ret_val; 1495 } 1496 1497 secattr->flags |= NETLBL_SECATTR_MLS_CAT; 1498 } 1499 1500 return 0; 1501 } 1502 1503 /** 1504 * cipso_v4_gentag_loc - Generate a CIPSO local tag (non-standard) 1505 * @doi_def: the DOI definition 1506 * @secattr: the security attributes 1507 * @buffer: the option buffer 1508 * @buffer_len: length of buffer in bytes 1509 * 1510 * Description: 1511 * Generate a CIPSO option using the local tag. Returns the size of the tag 1512 * on success, negative values on failure. 1513 * 1514 */ 1515 static int cipso_v4_gentag_loc(const struct cipso_v4_doi *doi_def, 1516 const struct netlbl_lsm_secattr *secattr, 1517 unsigned char *buffer, 1518 u32 buffer_len) 1519 { 1520 if (!(secattr->flags & NETLBL_SECATTR_SECID)) 1521 return -EPERM; 1522 1523 buffer[0] = CIPSO_V4_TAG_LOCAL; 1524 buffer[1] = CIPSO_V4_TAG_LOC_BLEN; 1525 *(u32 *)&buffer[2] = secattr->attr.secid; 1526 1527 return CIPSO_V4_TAG_LOC_BLEN; 1528 } 1529 1530 /** 1531 * cipso_v4_parsetag_loc - Parse a CIPSO local tag 1532 * @doi_def: the DOI definition 1533 * @tag: the CIPSO tag 1534 * @secattr: the security attributes 1535 * 1536 * Description: 1537 * Parse a CIPSO local tag and return the security attributes in @secattr. 1538 * Return zero on success, negatives values on failure. 1539 * 1540 */ 1541 static int cipso_v4_parsetag_loc(const struct cipso_v4_doi *doi_def, 1542 const unsigned char *tag, 1543 struct netlbl_lsm_secattr *secattr) 1544 { 1545 secattr->attr.secid = *(u32 *)&tag[2]; 1546 secattr->flags |= NETLBL_SECATTR_SECID; 1547 1548 return 0; 1549 } 1550 1551 /** 1552 * cipso_v4_validate - Validate a CIPSO option 1553 * @option: the start of the option, on error it is set to point to the error 1554 * 1555 * Description: 1556 * This routine is called to validate a CIPSO option, it checks all of the 1557 * fields to ensure that they are at least valid, see the draft snippet below 1558 * for details. If the option is valid then a zero value is returned and 1559 * the value of @option is unchanged. If the option is invalid then a 1560 * non-zero value is returned and @option is adjusted to point to the 1561 * offending portion of the option. From the IETF draft ... 1562 * 1563 * "If any field within the CIPSO options, such as the DOI identifier, is not 1564 * recognized the IP datagram is discarded and an ICMP 'parameter problem' 1565 * (type 12) is generated and returned. The ICMP code field is set to 'bad 1566 * parameter' (code 0) and the pointer is set to the start of the CIPSO field 1567 * that is unrecognized." 1568 * 1569 */ 1570 int cipso_v4_validate(const struct sk_buff *skb, unsigned char **option) 1571 { 1572 unsigned char *opt = *option; 1573 unsigned char *tag; 1574 unsigned char opt_iter; 1575 unsigned char err_offset = 0; 1576 u8 opt_len; 1577 u8 tag_len; 1578 struct cipso_v4_doi *doi_def = NULL; 1579 u32 tag_iter; 1580 1581 /* caller already checks for length values that are too large */ 1582 opt_len = opt[1]; 1583 if (opt_len < 8) { 1584 err_offset = 1; 1585 goto validate_return; 1586 } 1587 1588 rcu_read_lock(); 1589 doi_def = cipso_v4_doi_search(get_unaligned_be32(&opt[2])); 1590 if (doi_def == NULL) { 1591 err_offset = 2; 1592 goto validate_return_locked; 1593 } 1594 1595 opt_iter = CIPSO_V4_HDR_LEN; 1596 tag = opt + opt_iter; 1597 while (opt_iter < opt_len) { 1598 for (tag_iter = 0; doi_def->tags[tag_iter] != tag[0];) 1599 if (doi_def->tags[tag_iter] == CIPSO_V4_TAG_INVALID || 1600 ++tag_iter == CIPSO_V4_TAG_MAXCNT) { 1601 err_offset = opt_iter; 1602 goto validate_return_locked; 1603 } 1604 1605 tag_len = tag[1]; 1606 if (tag_len > (opt_len - opt_iter)) { 1607 err_offset = opt_iter + 1; 1608 goto validate_return_locked; 1609 } 1610 1611 switch (tag[0]) { 1612 case CIPSO_V4_TAG_RBITMAP: 1613 if (tag_len < CIPSO_V4_TAG_RBM_BLEN) { 1614 err_offset = opt_iter + 1; 1615 goto validate_return_locked; 1616 } 1617 1618 /* We are already going to do all the verification 1619 * necessary at the socket layer so from our point of 1620 * view it is safe to turn these checks off (and less 1621 * work), however, the CIPSO draft says we should do 1622 * all the CIPSO validations here but it doesn't 1623 * really specify _exactly_ what we need to validate 1624 * ... so, just make it a sysctl tunable. */ 1625 if (cipso_v4_rbm_strictvalid) { 1626 if (cipso_v4_map_lvl_valid(doi_def, 1627 tag[3]) < 0) { 1628 err_offset = opt_iter + 3; 1629 goto validate_return_locked; 1630 } 1631 if (tag_len > CIPSO_V4_TAG_RBM_BLEN && 1632 cipso_v4_map_cat_rbm_valid(doi_def, 1633 &tag[4], 1634 tag_len - 4) < 0) { 1635 err_offset = opt_iter + 4; 1636 goto validate_return_locked; 1637 } 1638 } 1639 break; 1640 case CIPSO_V4_TAG_ENUM: 1641 if (tag_len < CIPSO_V4_TAG_ENUM_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_ENUM_BLEN && 1652 cipso_v4_map_cat_enum_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_RANGE: 1660 if (tag_len < CIPSO_V4_TAG_RNG_BLEN) { 1661 err_offset = opt_iter + 1; 1662 goto validate_return_locked; 1663 } 1664 1665 if (cipso_v4_map_lvl_valid(doi_def, 1666 tag[3]) < 0) { 1667 err_offset = opt_iter + 3; 1668 goto validate_return_locked; 1669 } 1670 if (tag_len > CIPSO_V4_TAG_RNG_BLEN && 1671 cipso_v4_map_cat_rng_valid(doi_def, 1672 &tag[4], 1673 tag_len - 4) < 0) { 1674 err_offset = opt_iter + 4; 1675 goto validate_return_locked; 1676 } 1677 break; 1678 case CIPSO_V4_TAG_LOCAL: 1679 /* This is a non-standard tag that we only allow for 1680 * local connections, so if the incoming interface is 1681 * not the loopback device drop the packet. */ 1682 if (!(skb->dev->flags & IFF_LOOPBACK)) { 1683 err_offset = opt_iter; 1684 goto validate_return_locked; 1685 } 1686 if (tag_len != CIPSO_V4_TAG_LOC_BLEN) { 1687 err_offset = opt_iter + 1; 1688 goto validate_return_locked; 1689 } 1690 break; 1691 default: 1692 err_offset = opt_iter; 1693 goto validate_return_locked; 1694 } 1695 1696 tag += tag_len; 1697 opt_iter += tag_len; 1698 } 1699 1700 validate_return_locked: 1701 rcu_read_unlock(); 1702 validate_return: 1703 *option = opt + err_offset; 1704 return err_offset; 1705 } 1706 1707 /** 1708 * cipso_v4_error - Send the correct reponse for a bad packet 1709 * @skb: the packet 1710 * @error: the error code 1711 * @gateway: CIPSO gateway flag 1712 * 1713 * Description: 1714 * Based on the error code given in @error, send an ICMP error message back to 1715 * the originating host. From the IETF draft ... 1716 * 1717 * "If the contents of the CIPSO [option] are valid but the security label is 1718 * outside of the configured host or port label range, the datagram is 1719 * discarded and an ICMP 'destination unreachable' (type 3) is generated and 1720 * returned. The code field of the ICMP is set to 'communication with 1721 * destination network administratively prohibited' (code 9) or to 1722 * 'communication with destination host administratively prohibited' 1723 * (code 10). The value of the code is dependent on whether the originator 1724 * of the ICMP message is acting as a CIPSO host or a CIPSO gateway. The 1725 * recipient of the ICMP message MUST be able to handle either value. The 1726 * same procedure is performed if a CIPSO [option] can not be added to an 1727 * IP packet because it is too large to fit in the IP options area." 1728 * 1729 * "If the error is triggered by receipt of an ICMP message, the message is 1730 * discarded and no response is permitted (consistent with general ICMP 1731 * processing rules)." 1732 * 1733 */ 1734 void cipso_v4_error(struct sk_buff *skb, int error, u32 gateway) 1735 { 1736 if (ip_hdr(skb)->protocol == IPPROTO_ICMP || error != -EACCES) 1737 return; 1738 1739 if (gateway) 1740 icmp_send(skb, ICMP_DEST_UNREACH, ICMP_NET_ANO, 0); 1741 else 1742 icmp_send(skb, ICMP_DEST_UNREACH, ICMP_HOST_ANO, 0); 1743 } 1744 1745 /** 1746 * cipso_v4_genopt - Generate a CIPSO option 1747 * @buf: the option buffer 1748 * @buf_len: the size of opt_buf 1749 * @doi_def: the CIPSO DOI to use 1750 * @secattr: the security attributes 1751 * 1752 * Description: 1753 * Generate a CIPSO option using the DOI definition and security attributes 1754 * passed to the function. Returns the length of the option on success and 1755 * negative values on failure. 1756 * 1757 */ 1758 static int cipso_v4_genopt(unsigned char *buf, u32 buf_len, 1759 const struct cipso_v4_doi *doi_def, 1760 const struct netlbl_lsm_secattr *secattr) 1761 { 1762 int ret_val; 1763 u32 iter; 1764 1765 if (buf_len <= CIPSO_V4_HDR_LEN) 1766 return -ENOSPC; 1767 1768 /* XXX - This code assumes only one tag per CIPSO option which isn't 1769 * really a good assumption to make but since we only support the MAC 1770 * tags right now it is a safe assumption. */ 1771 iter = 0; 1772 do { 1773 memset(buf, 0, buf_len); 1774 switch (doi_def->tags[iter]) { 1775 case CIPSO_V4_TAG_RBITMAP: 1776 ret_val = cipso_v4_gentag_rbm(doi_def, 1777 secattr, 1778 &buf[CIPSO_V4_HDR_LEN], 1779 buf_len - CIPSO_V4_HDR_LEN); 1780 break; 1781 case CIPSO_V4_TAG_ENUM: 1782 ret_val = cipso_v4_gentag_enum(doi_def, 1783 secattr, 1784 &buf[CIPSO_V4_HDR_LEN], 1785 buf_len - CIPSO_V4_HDR_LEN); 1786 break; 1787 case CIPSO_V4_TAG_RANGE: 1788 ret_val = cipso_v4_gentag_rng(doi_def, 1789 secattr, 1790 &buf[CIPSO_V4_HDR_LEN], 1791 buf_len - CIPSO_V4_HDR_LEN); 1792 break; 1793 case CIPSO_V4_TAG_LOCAL: 1794 ret_val = cipso_v4_gentag_loc(doi_def, 1795 secattr, 1796 &buf[CIPSO_V4_HDR_LEN], 1797 buf_len - CIPSO_V4_HDR_LEN); 1798 break; 1799 default: 1800 return -EPERM; 1801 } 1802 1803 iter++; 1804 } while (ret_val < 0 && 1805 iter < CIPSO_V4_TAG_MAXCNT && 1806 doi_def->tags[iter] != CIPSO_V4_TAG_INVALID); 1807 if (ret_val < 0) 1808 return ret_val; 1809 cipso_v4_gentag_hdr(doi_def, buf, ret_val); 1810 return CIPSO_V4_HDR_LEN + ret_val; 1811 } 1812 1813 /** 1814 * cipso_v4_sock_setattr - Add a CIPSO option to a socket 1815 * @sk: the socket 1816 * @doi_def: the CIPSO DOI to use 1817 * @secattr: the specific security attributes of the socket 1818 * 1819 * Description: 1820 * Set the CIPSO option on the given socket using the DOI definition and 1821 * security attributes passed to the function. This function requires 1822 * exclusive access to @sk, which means it either needs to be in the 1823 * process of being created or locked. Returns zero on success and negative 1824 * values on failure. 1825 * 1826 */ 1827 int cipso_v4_sock_setattr(struct sock *sk, 1828 const struct cipso_v4_doi *doi_def, 1829 const struct netlbl_lsm_secattr *secattr) 1830 { 1831 int ret_val = -EPERM; 1832 unsigned char *buf = NULL; 1833 u32 buf_len; 1834 u32 opt_len; 1835 struct ip_options *opt = NULL; 1836 struct inet_sock *sk_inet; 1837 struct inet_connection_sock *sk_conn; 1838 1839 /* In the case of sock_create_lite(), the sock->sk field is not 1840 * defined yet but it is not a problem as the only users of these 1841 * "lite" PF_INET sockets are functions which do an accept() call 1842 * afterwards so we will label the socket as part of the accept(). */ 1843 if (sk == NULL) 1844 return 0; 1845 1846 /* We allocate the maximum CIPSO option size here so we are probably 1847 * being a little wasteful, but it makes our life _much_ easier later 1848 * on and after all we are only talking about 40 bytes. */ 1849 buf_len = CIPSO_V4_OPT_LEN_MAX; 1850 buf = kmalloc(buf_len, GFP_ATOMIC); 1851 if (buf == NULL) { 1852 ret_val = -ENOMEM; 1853 goto socket_setattr_failure; 1854 } 1855 1856 ret_val = cipso_v4_genopt(buf, buf_len, doi_def, secattr); 1857 if (ret_val < 0) 1858 goto socket_setattr_failure; 1859 buf_len = ret_val; 1860 1861 /* We can't use ip_options_get() directly because it makes a call to 1862 * ip_options_get_alloc() which allocates memory with GFP_KERNEL and 1863 * we won't always have CAP_NET_RAW even though we _always_ want to 1864 * set the IPOPT_CIPSO option. */ 1865 opt_len = (buf_len + 3) & ~3; 1866 opt = kzalloc(sizeof(*opt) + opt_len, GFP_ATOMIC); 1867 if (opt == NULL) { 1868 ret_val = -ENOMEM; 1869 goto socket_setattr_failure; 1870 } 1871 memcpy(opt->__data, buf, buf_len); 1872 opt->optlen = opt_len; 1873 opt->cipso = sizeof(struct iphdr); 1874 kfree(buf); 1875 buf = NULL; 1876 1877 sk_inet = inet_sk(sk); 1878 if (sk_inet->is_icsk) { 1879 sk_conn = inet_csk(sk); 1880 if (sk_inet->opt) 1881 sk_conn->icsk_ext_hdr_len -= sk_inet->opt->optlen; 1882 sk_conn->icsk_ext_hdr_len += opt->optlen; 1883 sk_conn->icsk_sync_mss(sk, sk_conn->icsk_pmtu_cookie); 1884 } 1885 opt = xchg(&sk_inet->opt, opt); 1886 kfree(opt); 1887 1888 return 0; 1889 1890 socket_setattr_failure: 1891 kfree(buf); 1892 kfree(opt); 1893 return ret_val; 1894 } 1895 1896 /** 1897 * cipso_v4_sock_delattr - Delete the CIPSO option from a socket 1898 * @sk: the socket 1899 * 1900 * Description: 1901 * Removes the CIPSO option from a socket, if present. 1902 * 1903 */ 1904 void cipso_v4_sock_delattr(struct sock *sk) 1905 { 1906 u8 hdr_delta; 1907 struct ip_options *opt; 1908 struct inet_sock *sk_inet; 1909 1910 sk_inet = inet_sk(sk); 1911 opt = sk_inet->opt; 1912 if (opt == NULL || opt->cipso == 0) 1913 return; 1914 1915 if (opt->srr || opt->rr || opt->ts || opt->router_alert) { 1916 u8 cipso_len; 1917 u8 cipso_off; 1918 unsigned char *cipso_ptr; 1919 int iter; 1920 int optlen_new; 1921 1922 cipso_off = opt->cipso - sizeof(struct iphdr); 1923 cipso_ptr = &opt->__data[cipso_off]; 1924 cipso_len = cipso_ptr[1]; 1925 1926 if (opt->srr > opt->cipso) 1927 opt->srr -= cipso_len; 1928 if (opt->rr > opt->cipso) 1929 opt->rr -= cipso_len; 1930 if (opt->ts > opt->cipso) 1931 opt->ts -= cipso_len; 1932 if (opt->router_alert > opt->cipso) 1933 opt->router_alert -= cipso_len; 1934 opt->cipso = 0; 1935 1936 memmove(cipso_ptr, cipso_ptr + cipso_len, 1937 opt->optlen - cipso_off - cipso_len); 1938 1939 /* determining the new total option length is tricky because of 1940 * the padding necessary, the only thing i can think to do at 1941 * this point is walk the options one-by-one, skipping the 1942 * padding at the end to determine the actual option size and 1943 * from there we can determine the new total option length */ 1944 iter = 0; 1945 optlen_new = 0; 1946 while (iter < opt->optlen) 1947 if (opt->__data[iter] != IPOPT_NOP) { 1948 iter += opt->__data[iter + 1]; 1949 optlen_new = iter; 1950 } else 1951 iter++; 1952 hdr_delta = opt->optlen; 1953 opt->optlen = (optlen_new + 3) & ~3; 1954 hdr_delta -= opt->optlen; 1955 } else { 1956 /* only the cipso option was present on the socket so we can 1957 * remove the entire option struct */ 1958 sk_inet->opt = NULL; 1959 hdr_delta = opt->optlen; 1960 kfree(opt); 1961 } 1962 1963 if (sk_inet->is_icsk && hdr_delta > 0) { 1964 struct inet_connection_sock *sk_conn = inet_csk(sk); 1965 sk_conn->icsk_ext_hdr_len -= hdr_delta; 1966 sk_conn->icsk_sync_mss(sk, sk_conn->icsk_pmtu_cookie); 1967 } 1968 } 1969 1970 /** 1971 * cipso_v4_getattr - Helper function for the cipso_v4_*_getattr functions 1972 * @cipso: the CIPSO v4 option 1973 * @secattr: the security attributes 1974 * 1975 * Description: 1976 * Inspect @cipso and return the security attributes in @secattr. Returns zero 1977 * on success and negative values on failure. 1978 * 1979 */ 1980 static int cipso_v4_getattr(const unsigned char *cipso, 1981 struct netlbl_lsm_secattr *secattr) 1982 { 1983 int ret_val = -ENOMSG; 1984 u32 doi; 1985 struct cipso_v4_doi *doi_def; 1986 1987 if (cipso_v4_cache_check(cipso, cipso[1], secattr) == 0) 1988 return 0; 1989 1990 doi = get_unaligned_be32(&cipso[2]); 1991 rcu_read_lock(); 1992 doi_def = cipso_v4_doi_search(doi); 1993 if (doi_def == NULL) 1994 goto getattr_return; 1995 /* XXX - This code assumes only one tag per CIPSO option which isn't 1996 * really a good assumption to make but since we only support the MAC 1997 * tags right now it is a safe assumption. */ 1998 switch (cipso[6]) { 1999 case CIPSO_V4_TAG_RBITMAP: 2000 ret_val = cipso_v4_parsetag_rbm(doi_def, &cipso[6], secattr); 2001 break; 2002 case CIPSO_V4_TAG_ENUM: 2003 ret_val = cipso_v4_parsetag_enum(doi_def, &cipso[6], secattr); 2004 break; 2005 case CIPSO_V4_TAG_RANGE: 2006 ret_val = cipso_v4_parsetag_rng(doi_def, &cipso[6], secattr); 2007 break; 2008 case CIPSO_V4_TAG_LOCAL: 2009 ret_val = cipso_v4_parsetag_loc(doi_def, &cipso[6], secattr); 2010 break; 2011 } 2012 if (ret_val == 0) 2013 secattr->type = NETLBL_NLTYPE_CIPSOV4; 2014 2015 getattr_return: 2016 rcu_read_unlock(); 2017 return ret_val; 2018 } 2019 2020 /** 2021 * cipso_v4_sock_getattr - Get the security attributes from a sock 2022 * @sk: the sock 2023 * @secattr: the security attributes 2024 * 2025 * Description: 2026 * Query @sk to see if there is a CIPSO option attached to the sock and if 2027 * there is return the CIPSO security attributes in @secattr. This function 2028 * requires that @sk be locked, or privately held, but it does not do any 2029 * locking itself. Returns zero on success and negative values on failure. 2030 * 2031 */ 2032 int cipso_v4_sock_getattr(struct sock *sk, struct netlbl_lsm_secattr *secattr) 2033 { 2034 struct ip_options *opt; 2035 2036 opt = inet_sk(sk)->opt; 2037 if (opt == NULL || opt->cipso == 0) 2038 return -ENOMSG; 2039 2040 return cipso_v4_getattr(opt->__data + opt->cipso - sizeof(struct iphdr), 2041 secattr); 2042 } 2043 2044 /** 2045 * cipso_v4_skbuff_setattr - Set the CIPSO option on a packet 2046 * @skb: the packet 2047 * @secattr: the security attributes 2048 * 2049 * Description: 2050 * Set the CIPSO option on the given packet based on the security attributes. 2051 * Returns a pointer to the IP header on success and NULL on failure. 2052 * 2053 */ 2054 int cipso_v4_skbuff_setattr(struct sk_buff *skb, 2055 const struct cipso_v4_doi *doi_def, 2056 const struct netlbl_lsm_secattr *secattr) 2057 { 2058 int ret_val; 2059 struct iphdr *iph; 2060 struct ip_options *opt = &IPCB(skb)->opt; 2061 unsigned char buf[CIPSO_V4_OPT_LEN_MAX]; 2062 u32 buf_len = CIPSO_V4_OPT_LEN_MAX; 2063 u32 opt_len; 2064 int len_delta; 2065 2066 ret_val = cipso_v4_genopt(buf, buf_len, doi_def, secattr); 2067 if (ret_val < 0) 2068 return ret_val; 2069 buf_len = ret_val; 2070 opt_len = (buf_len + 3) & ~3; 2071 2072 /* we overwrite any existing options to ensure that we have enough 2073 * room for the CIPSO option, the reason is that we _need_ to guarantee 2074 * that the security label is applied to the packet - we do the same 2075 * thing when using the socket options and it hasn't caused a problem, 2076 * if we need to we can always revisit this choice later */ 2077 2078 len_delta = opt_len - opt->optlen; 2079 /* if we don't ensure enough headroom we could panic on the skb_push() 2080 * call below so make sure we have enough, we are also "mangling" the 2081 * packet so we should probably do a copy-on-write call anyway */ 2082 ret_val = skb_cow(skb, skb_headroom(skb) + len_delta); 2083 if (ret_val < 0) 2084 return ret_val; 2085 2086 if (len_delta > 0) { 2087 /* we assume that the header + opt->optlen have already been 2088 * "pushed" in ip_options_build() or similar */ 2089 iph = ip_hdr(skb); 2090 skb_push(skb, len_delta); 2091 memmove((char *)iph - len_delta, iph, iph->ihl << 2); 2092 skb_reset_network_header(skb); 2093 iph = ip_hdr(skb); 2094 } else if (len_delta < 0) { 2095 iph = ip_hdr(skb); 2096 memset(iph + 1, IPOPT_NOP, opt->optlen); 2097 } else 2098 iph = ip_hdr(skb); 2099 2100 if (opt->optlen > 0) 2101 memset(opt, 0, sizeof(*opt)); 2102 opt->optlen = opt_len; 2103 opt->cipso = sizeof(struct iphdr); 2104 opt->is_changed = 1; 2105 2106 /* we have to do the following because we are being called from a 2107 * netfilter hook which means the packet already has had the header 2108 * fields populated and the checksum calculated - yes this means we 2109 * are doing more work than needed but we do it to keep the core 2110 * stack clean and tidy */ 2111 memcpy(iph + 1, buf, buf_len); 2112 if (opt_len > buf_len) 2113 memset((char *)(iph + 1) + buf_len, 0, opt_len - buf_len); 2114 if (len_delta != 0) { 2115 iph->ihl = 5 + (opt_len >> 2); 2116 iph->tot_len = htons(skb->len); 2117 } 2118 ip_send_check(iph); 2119 2120 return 0; 2121 } 2122 2123 /** 2124 * cipso_v4_skbuff_delattr - Delete any CIPSO options from a packet 2125 * @skb: the packet 2126 * 2127 * Description: 2128 * Removes any and all CIPSO options from the given packet. Returns zero on 2129 * success, negative values on failure. 2130 * 2131 */ 2132 int cipso_v4_skbuff_delattr(struct sk_buff *skb) 2133 { 2134 int ret_val; 2135 struct iphdr *iph; 2136 struct ip_options *opt = &IPCB(skb)->opt; 2137 unsigned char *cipso_ptr; 2138 2139 if (opt->cipso == 0) 2140 return 0; 2141 2142 /* since we are changing the packet we should make a copy */ 2143 ret_val = skb_cow(skb, skb_headroom(skb)); 2144 if (ret_val < 0) 2145 return ret_val; 2146 2147 /* the easiest thing to do is just replace the cipso option with noop 2148 * options since we don't change the size of the packet, although we 2149 * still need to recalculate the checksum */ 2150 2151 iph = ip_hdr(skb); 2152 cipso_ptr = (unsigned char *)iph + opt->cipso; 2153 memset(cipso_ptr, IPOPT_NOOP, cipso_ptr[1]); 2154 opt->cipso = 0; 2155 opt->is_changed = 1; 2156 2157 ip_send_check(iph); 2158 2159 return 0; 2160 } 2161 2162 /** 2163 * cipso_v4_skbuff_getattr - Get the security attributes from the CIPSO option 2164 * @skb: the packet 2165 * @secattr: the security attributes 2166 * 2167 * Description: 2168 * Parse the given packet's CIPSO option and return the security attributes. 2169 * Returns zero on success and negative values on failure. 2170 * 2171 */ 2172 int cipso_v4_skbuff_getattr(const struct sk_buff *skb, 2173 struct netlbl_lsm_secattr *secattr) 2174 { 2175 return cipso_v4_getattr(CIPSO_V4_OPTPTR(skb), secattr); 2176 } 2177 2178 /* 2179 * Setup Functions 2180 */ 2181 2182 /** 2183 * cipso_v4_init - Initialize the CIPSO module 2184 * 2185 * Description: 2186 * Initialize the CIPSO module and prepare it for use. Returns zero on success 2187 * and negative values on failure. 2188 * 2189 */ 2190 static int __init cipso_v4_init(void) 2191 { 2192 int ret_val; 2193 2194 ret_val = cipso_v4_cache_init(); 2195 if (ret_val != 0) 2196 panic("Failed to initialize the CIPSO/IPv4 cache (%d)\n", 2197 ret_val); 2198 2199 return 0; 2200 } 2201 2202 subsys_initcall(cipso_v4_init); 2203