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. While CIPSO never became a full IETF RFC standard many vendors 7 * have chosen to adopt the protocol and over the years it has become a 8 * de-facto standard for labeled networking. 9 * 10 * The CIPSO draft specification can be found in the kernel's Documentation 11 * directory as well as the following URL: 12 * http://tools.ietf.org/id/draft-ietf-cipso-ipsecurity-01.txt 13 * The FIPS-188 specification can be found at the following URL: 14 * http://www.itl.nist.gov/fipspubs/fip188.htm 15 * 16 * Author: Paul Moore <paul.moore@hp.com> 17 * 18 */ 19 20 /* 21 * (c) Copyright Hewlett-Packard Development Company, L.P., 2006, 2008 22 * 23 * This program is free software; you can redistribute it and/or modify 24 * it under the terms of the GNU General Public License as published by 25 * the Free Software Foundation; either version 2 of the License, or 26 * (at your option) any later version. 27 * 28 * This program is distributed in the hope that it will be useful, 29 * but WITHOUT ANY WARRANTY; without even the implied warranty of 30 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See 31 * the GNU General Public License for more details. 32 * 33 * You should have received a copy of the GNU General Public License 34 * along with this program; if not, see <http://www.gnu.org/licenses/>. 35 * 36 */ 37 38 #include <linux/init.h> 39 #include <linux/types.h> 40 #include <linux/rcupdate.h> 41 #include <linux/list.h> 42 #include <linux/spinlock.h> 43 #include <linux/string.h> 44 #include <linux/jhash.h> 45 #include <linux/audit.h> 46 #include <linux/slab.h> 47 #include <net/ip.h> 48 #include <net/icmp.h> 49 #include <net/tcp.h> 50 #include <net/netlabel.h> 51 #include <net/cipso_ipv4.h> 52 #include <linux/atomic.h> 53 #include <linux/bug.h> 54 #include <asm/unaligned.h> 55 56 /* List of available DOI definitions */ 57 /* XXX - This currently assumes a minimal number of different DOIs in use, 58 * if in practice there are a lot of different DOIs this list should 59 * probably be turned into a hash table or something similar so we 60 * can do quick lookups. */ 61 static DEFINE_SPINLOCK(cipso_v4_doi_list_lock); 62 static LIST_HEAD(cipso_v4_doi_list); 63 64 /* Label mapping cache */ 65 int cipso_v4_cache_enabled = 1; 66 int cipso_v4_cache_bucketsize = 10; 67 #define CIPSO_V4_CACHE_BUCKETBITS 7 68 #define CIPSO_V4_CACHE_BUCKETS (1 << CIPSO_V4_CACHE_BUCKETBITS) 69 #define CIPSO_V4_CACHE_REORDERLIMIT 10 70 struct cipso_v4_map_cache_bkt { 71 spinlock_t lock; 72 u32 size; 73 struct list_head list; 74 }; 75 76 struct cipso_v4_map_cache_entry { 77 u32 hash; 78 unsigned char *key; 79 size_t key_len; 80 81 struct netlbl_lsm_cache *lsm_data; 82 83 u32 activity; 84 struct list_head list; 85 }; 86 87 static struct cipso_v4_map_cache_bkt *cipso_v4_cache; 88 89 /* Restricted bitmap (tag #1) flags */ 90 int cipso_v4_rbm_optfmt = 0; 91 int cipso_v4_rbm_strictvalid = 1; 92 93 /* 94 * Protocol Constants 95 */ 96 97 /* Maximum size of the CIPSO IP option, derived from the fact that the maximum 98 * IPv4 header size is 60 bytes and the base IPv4 header is 20 bytes long. */ 99 #define CIPSO_V4_OPT_LEN_MAX 40 100 101 /* Length of the base CIPSO option, this includes the option type (1 byte), the 102 * option length (1 byte), and the DOI (4 bytes). */ 103 #define CIPSO_V4_HDR_LEN 6 104 105 /* Base length of the restrictive category bitmap tag (tag #1). */ 106 #define CIPSO_V4_TAG_RBM_BLEN 4 107 108 /* Base length of the enumerated category tag (tag #2). */ 109 #define CIPSO_V4_TAG_ENUM_BLEN 4 110 111 /* Base length of the ranged categories bitmap tag (tag #5). */ 112 #define CIPSO_V4_TAG_RNG_BLEN 4 113 /* The maximum number of category ranges permitted in the ranged category tag 114 * (tag #5). You may note that the IETF draft states that the maximum number 115 * of category ranges is 7, but if the low end of the last category range is 116 * zero then it is possible to fit 8 category ranges because the zero should 117 * be omitted. */ 118 #define CIPSO_V4_TAG_RNG_CAT_MAX 8 119 120 /* Base length of the local tag (non-standard tag). 121 * Tag definition (may change between kernel versions) 122 * 123 * 0 8 16 24 32 124 * +----------+----------+----------+----------+ 125 * | 10000000 | 00000110 | 32-bit secid value | 126 * +----------+----------+----------+----------+ 127 * | in (host byte order)| 128 * +----------+----------+ 129 * 130 */ 131 #define CIPSO_V4_TAG_LOC_BLEN 6 132 133 /* 134 * Helper Functions 135 */ 136 137 /** 138 * cipso_v4_cache_entry_free - Frees a cache entry 139 * @entry: the entry to free 140 * 141 * Description: 142 * This function frees the memory associated with a cache entry including the 143 * LSM cache data if there are no longer any users, i.e. reference count == 0. 144 * 145 */ 146 static void cipso_v4_cache_entry_free(struct cipso_v4_map_cache_entry *entry) 147 { 148 if (entry->lsm_data) 149 netlbl_secattr_cache_free(entry->lsm_data); 150 kfree(entry->key); 151 kfree(entry); 152 } 153 154 /** 155 * cipso_v4_map_cache_hash - Hashing function for the CIPSO cache 156 * @key: the hash key 157 * @key_len: the length of the key in bytes 158 * 159 * Description: 160 * The CIPSO tag hashing function. Returns a 32-bit hash value. 161 * 162 */ 163 static u32 cipso_v4_map_cache_hash(const unsigned char *key, u32 key_len) 164 { 165 return jhash(key, key_len, 0); 166 } 167 168 /* 169 * Label Mapping Cache Functions 170 */ 171 172 /** 173 * cipso_v4_cache_init - Initialize the CIPSO cache 174 * 175 * Description: 176 * Initializes the CIPSO label mapping cache, this function should be called 177 * before any of the other functions defined in this file. Returns zero on 178 * success, negative values on error. 179 * 180 */ 181 static int __init cipso_v4_cache_init(void) 182 { 183 u32 iter; 184 185 cipso_v4_cache = kcalloc(CIPSO_V4_CACHE_BUCKETS, 186 sizeof(struct cipso_v4_map_cache_bkt), 187 GFP_KERNEL); 188 if (!cipso_v4_cache) 189 return -ENOMEM; 190 191 for (iter = 0; iter < CIPSO_V4_CACHE_BUCKETS; iter++) { 192 spin_lock_init(&cipso_v4_cache[iter].lock); 193 cipso_v4_cache[iter].size = 0; 194 INIT_LIST_HEAD(&cipso_v4_cache[iter].list); 195 } 196 197 return 0; 198 } 199 200 /** 201 * cipso_v4_cache_invalidate - Invalidates the current CIPSO cache 202 * 203 * Description: 204 * Invalidates and frees any entries in the CIPSO cache. Returns zero on 205 * success and negative values on failure. 206 * 207 */ 208 void cipso_v4_cache_invalidate(void) 209 { 210 struct cipso_v4_map_cache_entry *entry, *tmp_entry; 211 u32 iter; 212 213 for (iter = 0; iter < CIPSO_V4_CACHE_BUCKETS; iter++) { 214 spin_lock_bh(&cipso_v4_cache[iter].lock); 215 list_for_each_entry_safe(entry, 216 tmp_entry, 217 &cipso_v4_cache[iter].list, list) { 218 list_del(&entry->list); 219 cipso_v4_cache_entry_free(entry); 220 } 221 cipso_v4_cache[iter].size = 0; 222 spin_unlock_bh(&cipso_v4_cache[iter].lock); 223 } 224 } 225 226 /** 227 * cipso_v4_cache_check - Check the CIPSO cache for a label mapping 228 * @key: the buffer to check 229 * @key_len: buffer length in bytes 230 * @secattr: the security attribute struct to use 231 * 232 * Description: 233 * This function checks the cache to see if a label mapping already exists for 234 * the given key. If there is a match then the cache is adjusted and the 235 * @secattr struct is populated with the correct LSM security attributes. The 236 * cache is adjusted in the following manner if the entry is not already the 237 * first in the cache bucket: 238 * 239 * 1. The cache entry's activity counter is incremented 240 * 2. The previous (higher ranking) entry's activity counter is decremented 241 * 3. If the difference between the two activity counters is geater than 242 * CIPSO_V4_CACHE_REORDERLIMIT the two entries are swapped 243 * 244 * Returns zero on success, -ENOENT for a cache miss, and other negative values 245 * on error. 246 * 247 */ 248 static int cipso_v4_cache_check(const unsigned char *key, 249 u32 key_len, 250 struct netlbl_lsm_secattr *secattr) 251 { 252 u32 bkt; 253 struct cipso_v4_map_cache_entry *entry; 254 struct cipso_v4_map_cache_entry *prev_entry = NULL; 255 u32 hash; 256 257 if (!cipso_v4_cache_enabled) 258 return -ENOENT; 259 260 hash = cipso_v4_map_cache_hash(key, key_len); 261 bkt = hash & (CIPSO_V4_CACHE_BUCKETS - 1); 262 spin_lock_bh(&cipso_v4_cache[bkt].lock); 263 list_for_each_entry(entry, &cipso_v4_cache[bkt].list, list) { 264 if (entry->hash == hash && 265 entry->key_len == key_len && 266 memcmp(entry->key, key, key_len) == 0) { 267 entry->activity += 1; 268 atomic_inc(&entry->lsm_data->refcount); 269 secattr->cache = entry->lsm_data; 270 secattr->flags |= NETLBL_SECATTR_CACHE; 271 secattr->type = NETLBL_NLTYPE_CIPSOV4; 272 if (!prev_entry) { 273 spin_unlock_bh(&cipso_v4_cache[bkt].lock); 274 return 0; 275 } 276 277 if (prev_entry->activity > 0) 278 prev_entry->activity -= 1; 279 if (entry->activity > prev_entry->activity && 280 entry->activity - prev_entry->activity > 281 CIPSO_V4_CACHE_REORDERLIMIT) { 282 __list_del(entry->list.prev, entry->list.next); 283 __list_add(&entry->list, 284 prev_entry->list.prev, 285 &prev_entry->list); 286 } 287 288 spin_unlock_bh(&cipso_v4_cache[bkt].lock); 289 return 0; 290 } 291 prev_entry = entry; 292 } 293 spin_unlock_bh(&cipso_v4_cache[bkt].lock); 294 295 return -ENOENT; 296 } 297 298 /** 299 * cipso_v4_cache_add - Add an entry to the CIPSO cache 300 * @skb: the packet 301 * @secattr: the packet's security attributes 302 * 303 * Description: 304 * Add a new entry into the CIPSO label mapping cache. Add the new entry to 305 * head of the cache bucket's list, if the cache bucket is out of room remove 306 * the last entry in the list first. It is important to note that there is 307 * currently no checking for duplicate keys. Returns zero on success, 308 * negative values on failure. 309 * 310 */ 311 int cipso_v4_cache_add(const unsigned char *cipso_ptr, 312 const struct netlbl_lsm_secattr *secattr) 313 { 314 int ret_val = -EPERM; 315 u32 bkt; 316 struct cipso_v4_map_cache_entry *entry = NULL; 317 struct cipso_v4_map_cache_entry *old_entry = NULL; 318 u32 cipso_ptr_len; 319 320 if (!cipso_v4_cache_enabled || cipso_v4_cache_bucketsize <= 0) 321 return 0; 322 323 cipso_ptr_len = cipso_ptr[1]; 324 325 entry = kzalloc(sizeof(*entry), GFP_ATOMIC); 326 if (!entry) 327 return -ENOMEM; 328 entry->key = kmemdup(cipso_ptr, cipso_ptr_len, GFP_ATOMIC); 329 if (!entry->key) { 330 ret_val = -ENOMEM; 331 goto cache_add_failure; 332 } 333 entry->key_len = cipso_ptr_len; 334 entry->hash = cipso_v4_map_cache_hash(cipso_ptr, cipso_ptr_len); 335 atomic_inc(&secattr->cache->refcount); 336 entry->lsm_data = secattr->cache; 337 338 bkt = entry->hash & (CIPSO_V4_CACHE_BUCKETS - 1); 339 spin_lock_bh(&cipso_v4_cache[bkt].lock); 340 if (cipso_v4_cache[bkt].size < cipso_v4_cache_bucketsize) { 341 list_add(&entry->list, &cipso_v4_cache[bkt].list); 342 cipso_v4_cache[bkt].size += 1; 343 } else { 344 old_entry = list_entry(cipso_v4_cache[bkt].list.prev, 345 struct cipso_v4_map_cache_entry, list); 346 list_del(&old_entry->list); 347 list_add(&entry->list, &cipso_v4_cache[bkt].list); 348 cipso_v4_cache_entry_free(old_entry); 349 } 350 spin_unlock_bh(&cipso_v4_cache[bkt].lock); 351 352 return 0; 353 354 cache_add_failure: 355 if (entry) 356 cipso_v4_cache_entry_free(entry); 357 return ret_val; 358 } 359 360 /* 361 * DOI List Functions 362 */ 363 364 /** 365 * cipso_v4_doi_search - Searches for a DOI definition 366 * @doi: the DOI to search for 367 * 368 * Description: 369 * Search the DOI definition list for a DOI definition with a DOI value that 370 * matches @doi. The caller is responsible for calling rcu_read_[un]lock(). 371 * Returns a pointer to the DOI definition on success and NULL on failure. 372 */ 373 static struct cipso_v4_doi *cipso_v4_doi_search(u32 doi) 374 { 375 struct cipso_v4_doi *iter; 376 377 list_for_each_entry_rcu(iter, &cipso_v4_doi_list, list) 378 if (iter->doi == doi && atomic_read(&iter->refcount)) 379 return iter; 380 return NULL; 381 } 382 383 /** 384 * cipso_v4_doi_add - Add a new DOI to the CIPSO protocol engine 385 * @doi_def: the DOI structure 386 * @audit_info: NetLabel audit information 387 * 388 * Description: 389 * The caller defines a new DOI for use by the CIPSO engine and calls this 390 * function to add it to the list of acceptable domains. The caller must 391 * ensure that the mapping table specified in @doi_def->map meets all of the 392 * requirements of the mapping type (see cipso_ipv4.h for details). Returns 393 * zero on success and non-zero on failure. 394 * 395 */ 396 int cipso_v4_doi_add(struct cipso_v4_doi *doi_def, 397 struct netlbl_audit *audit_info) 398 { 399 int ret_val = -EINVAL; 400 u32 iter; 401 u32 doi; 402 u32 doi_type; 403 struct audit_buffer *audit_buf; 404 405 doi = doi_def->doi; 406 doi_type = doi_def->type; 407 408 if (doi_def->doi == CIPSO_V4_DOI_UNKNOWN) 409 goto doi_add_return; 410 for (iter = 0; iter < CIPSO_V4_TAG_MAXCNT; iter++) { 411 switch (doi_def->tags[iter]) { 412 case CIPSO_V4_TAG_RBITMAP: 413 break; 414 case CIPSO_V4_TAG_RANGE: 415 case CIPSO_V4_TAG_ENUM: 416 if (doi_def->type != CIPSO_V4_MAP_PASS) 417 goto doi_add_return; 418 break; 419 case CIPSO_V4_TAG_LOCAL: 420 if (doi_def->type != CIPSO_V4_MAP_LOCAL) 421 goto doi_add_return; 422 break; 423 case CIPSO_V4_TAG_INVALID: 424 if (iter == 0) 425 goto doi_add_return; 426 break; 427 default: 428 goto doi_add_return; 429 } 430 } 431 432 atomic_set(&doi_def->refcount, 1); 433 434 spin_lock(&cipso_v4_doi_list_lock); 435 if (cipso_v4_doi_search(doi_def->doi)) { 436 spin_unlock(&cipso_v4_doi_list_lock); 437 ret_val = -EEXIST; 438 goto doi_add_return; 439 } 440 list_add_tail_rcu(&doi_def->list, &cipso_v4_doi_list); 441 spin_unlock(&cipso_v4_doi_list_lock); 442 ret_val = 0; 443 444 doi_add_return: 445 audit_buf = netlbl_audit_start(AUDIT_MAC_CIPSOV4_ADD, audit_info); 446 if (audit_buf) { 447 const char *type_str; 448 switch (doi_type) { 449 case CIPSO_V4_MAP_TRANS: 450 type_str = "trans"; 451 break; 452 case CIPSO_V4_MAP_PASS: 453 type_str = "pass"; 454 break; 455 case CIPSO_V4_MAP_LOCAL: 456 type_str = "local"; 457 break; 458 default: 459 type_str = "(unknown)"; 460 } 461 audit_log_format(audit_buf, 462 " cipso_doi=%u cipso_type=%s res=%u", 463 doi, type_str, ret_val == 0 ? 1 : 0); 464 audit_log_end(audit_buf); 465 } 466 467 return ret_val; 468 } 469 470 /** 471 * cipso_v4_doi_free - Frees a DOI definition 472 * @doi_def: the DOI definition 473 * 474 * Description: 475 * This function frees all of the memory associated with a DOI definition. 476 * 477 */ 478 void cipso_v4_doi_free(struct cipso_v4_doi *doi_def) 479 { 480 if (!doi_def) 481 return; 482 483 switch (doi_def->type) { 484 case CIPSO_V4_MAP_TRANS: 485 kfree(doi_def->map.std->lvl.cipso); 486 kfree(doi_def->map.std->lvl.local); 487 kfree(doi_def->map.std->cat.cipso); 488 kfree(doi_def->map.std->cat.local); 489 break; 490 } 491 kfree(doi_def); 492 } 493 494 /** 495 * cipso_v4_doi_free_rcu - Frees a DOI definition via the RCU pointer 496 * @entry: the entry's RCU field 497 * 498 * Description: 499 * This function is designed to be used as a callback to the call_rcu() 500 * function so that the memory allocated to the DOI definition can be released 501 * safely. 502 * 503 */ 504 static void cipso_v4_doi_free_rcu(struct rcu_head *entry) 505 { 506 struct cipso_v4_doi *doi_def; 507 508 doi_def = container_of(entry, struct cipso_v4_doi, rcu); 509 cipso_v4_doi_free(doi_def); 510 } 511 512 /** 513 * cipso_v4_doi_remove - Remove an existing DOI from the CIPSO protocol engine 514 * @doi: the DOI value 515 * @audit_secid: the LSM secid to use in the audit message 516 * 517 * Description: 518 * Removes a DOI definition from the CIPSO engine. The NetLabel routines will 519 * be called to release their own LSM domain mappings as well as our own 520 * domain list. Returns zero on success and negative values on failure. 521 * 522 */ 523 int cipso_v4_doi_remove(u32 doi, struct netlbl_audit *audit_info) 524 { 525 int ret_val; 526 struct cipso_v4_doi *doi_def; 527 struct audit_buffer *audit_buf; 528 529 spin_lock(&cipso_v4_doi_list_lock); 530 doi_def = cipso_v4_doi_search(doi); 531 if (!doi_def) { 532 spin_unlock(&cipso_v4_doi_list_lock); 533 ret_val = -ENOENT; 534 goto doi_remove_return; 535 } 536 if (!atomic_dec_and_test(&doi_def->refcount)) { 537 spin_unlock(&cipso_v4_doi_list_lock); 538 ret_val = -EBUSY; 539 goto doi_remove_return; 540 } 541 list_del_rcu(&doi_def->list); 542 spin_unlock(&cipso_v4_doi_list_lock); 543 544 cipso_v4_cache_invalidate(); 545 call_rcu(&doi_def->rcu, cipso_v4_doi_free_rcu); 546 ret_val = 0; 547 548 doi_remove_return: 549 audit_buf = netlbl_audit_start(AUDIT_MAC_CIPSOV4_DEL, audit_info); 550 if (audit_buf) { 551 audit_log_format(audit_buf, 552 " cipso_doi=%u res=%u", 553 doi, ret_val == 0 ? 1 : 0); 554 audit_log_end(audit_buf); 555 } 556 557 return ret_val; 558 } 559 560 /** 561 * cipso_v4_doi_getdef - Returns a reference to a valid DOI definition 562 * @doi: the DOI value 563 * 564 * Description: 565 * Searches for a valid DOI definition and if one is found it is returned to 566 * the caller. Otherwise NULL is returned. The caller must ensure that 567 * rcu_read_lock() is held while accessing the returned definition and the DOI 568 * definition reference count is decremented when the caller is done. 569 * 570 */ 571 struct cipso_v4_doi *cipso_v4_doi_getdef(u32 doi) 572 { 573 struct cipso_v4_doi *doi_def; 574 575 rcu_read_lock(); 576 doi_def = cipso_v4_doi_search(doi); 577 if (!doi_def) 578 goto doi_getdef_return; 579 if (!atomic_inc_not_zero(&doi_def->refcount)) 580 doi_def = NULL; 581 582 doi_getdef_return: 583 rcu_read_unlock(); 584 return doi_def; 585 } 586 587 /** 588 * cipso_v4_doi_putdef - Releases a reference for the given DOI definition 589 * @doi_def: the DOI definition 590 * 591 * Description: 592 * Releases a DOI definition reference obtained from cipso_v4_doi_getdef(). 593 * 594 */ 595 void cipso_v4_doi_putdef(struct cipso_v4_doi *doi_def) 596 { 597 if (!doi_def) 598 return; 599 600 if (!atomic_dec_and_test(&doi_def->refcount)) 601 return; 602 spin_lock(&cipso_v4_doi_list_lock); 603 list_del_rcu(&doi_def->list); 604 spin_unlock(&cipso_v4_doi_list_lock); 605 606 cipso_v4_cache_invalidate(); 607 call_rcu(&doi_def->rcu, cipso_v4_doi_free_rcu); 608 } 609 610 /** 611 * cipso_v4_doi_walk - Iterate through the DOI definitions 612 * @skip_cnt: skip past this number of DOI definitions, updated 613 * @callback: callback for each DOI definition 614 * @cb_arg: argument for the callback function 615 * 616 * Description: 617 * Iterate over the DOI definition list, skipping the first @skip_cnt entries. 618 * For each entry call @callback, if @callback returns a negative value stop 619 * 'walking' through the list and return. Updates the value in @skip_cnt upon 620 * return. Returns zero on success, negative values on failure. 621 * 622 */ 623 int cipso_v4_doi_walk(u32 *skip_cnt, 624 int (*callback) (struct cipso_v4_doi *doi_def, void *arg), 625 void *cb_arg) 626 { 627 int ret_val = -ENOENT; 628 u32 doi_cnt = 0; 629 struct cipso_v4_doi *iter_doi; 630 631 rcu_read_lock(); 632 list_for_each_entry_rcu(iter_doi, &cipso_v4_doi_list, list) 633 if (atomic_read(&iter_doi->refcount) > 0) { 634 if (doi_cnt++ < *skip_cnt) 635 continue; 636 ret_val = callback(iter_doi, cb_arg); 637 if (ret_val < 0) { 638 doi_cnt--; 639 goto doi_walk_return; 640 } 641 } 642 643 doi_walk_return: 644 rcu_read_unlock(); 645 *skip_cnt = doi_cnt; 646 return ret_val; 647 } 648 649 /* 650 * Label Mapping Functions 651 */ 652 653 /** 654 * cipso_v4_map_lvl_valid - Checks to see if the given level is understood 655 * @doi_def: the DOI definition 656 * @level: the level to check 657 * 658 * Description: 659 * Checks the given level against the given DOI definition and returns a 660 * negative value if the level does not have a valid mapping and a zero value 661 * if the level is defined by the DOI. 662 * 663 */ 664 static int cipso_v4_map_lvl_valid(const struct cipso_v4_doi *doi_def, u8 level) 665 { 666 switch (doi_def->type) { 667 case CIPSO_V4_MAP_PASS: 668 return 0; 669 case CIPSO_V4_MAP_TRANS: 670 if (doi_def->map.std->lvl.cipso[level] < CIPSO_V4_INV_LVL) 671 return 0; 672 break; 673 } 674 675 return -EFAULT; 676 } 677 678 /** 679 * cipso_v4_map_lvl_hton - Perform a level mapping from the host to the network 680 * @doi_def: the DOI definition 681 * @host_lvl: the host MLS level 682 * @net_lvl: the network/CIPSO MLS level 683 * 684 * Description: 685 * Perform a label mapping to translate a local MLS level to the correct 686 * CIPSO level using the given DOI definition. Returns zero on success, 687 * negative values otherwise. 688 * 689 */ 690 static int cipso_v4_map_lvl_hton(const struct cipso_v4_doi *doi_def, 691 u32 host_lvl, 692 u32 *net_lvl) 693 { 694 switch (doi_def->type) { 695 case CIPSO_V4_MAP_PASS: 696 *net_lvl = host_lvl; 697 return 0; 698 case CIPSO_V4_MAP_TRANS: 699 if (host_lvl < doi_def->map.std->lvl.local_size && 700 doi_def->map.std->lvl.local[host_lvl] < CIPSO_V4_INV_LVL) { 701 *net_lvl = doi_def->map.std->lvl.local[host_lvl]; 702 return 0; 703 } 704 return -EPERM; 705 } 706 707 return -EINVAL; 708 } 709 710 /** 711 * cipso_v4_map_lvl_ntoh - Perform a level mapping from the network to the host 712 * @doi_def: the DOI definition 713 * @net_lvl: the network/CIPSO MLS level 714 * @host_lvl: the host MLS level 715 * 716 * Description: 717 * Perform a label mapping to translate a CIPSO level to the correct local MLS 718 * level using the given DOI definition. Returns zero on success, negative 719 * values otherwise. 720 * 721 */ 722 static int cipso_v4_map_lvl_ntoh(const struct cipso_v4_doi *doi_def, 723 u32 net_lvl, 724 u32 *host_lvl) 725 { 726 struct cipso_v4_std_map_tbl *map_tbl; 727 728 switch (doi_def->type) { 729 case CIPSO_V4_MAP_PASS: 730 *host_lvl = net_lvl; 731 return 0; 732 case CIPSO_V4_MAP_TRANS: 733 map_tbl = doi_def->map.std; 734 if (net_lvl < map_tbl->lvl.cipso_size && 735 map_tbl->lvl.cipso[net_lvl] < CIPSO_V4_INV_LVL) { 736 *host_lvl = doi_def->map.std->lvl.cipso[net_lvl]; 737 return 0; 738 } 739 return -EPERM; 740 } 741 742 return -EINVAL; 743 } 744 745 /** 746 * cipso_v4_map_cat_rbm_valid - Checks to see if the category bitmap is valid 747 * @doi_def: the DOI definition 748 * @bitmap: category bitmap 749 * @bitmap_len: bitmap length in bytes 750 * 751 * Description: 752 * Checks the given category bitmap against the given DOI definition and 753 * returns a negative value if any of the categories in the bitmap do not have 754 * a valid mapping and a zero value if all of the categories are valid. 755 * 756 */ 757 static int cipso_v4_map_cat_rbm_valid(const struct cipso_v4_doi *doi_def, 758 const unsigned char *bitmap, 759 u32 bitmap_len) 760 { 761 int cat = -1; 762 u32 bitmap_len_bits = bitmap_len * 8; 763 u32 cipso_cat_size; 764 u32 *cipso_array; 765 766 switch (doi_def->type) { 767 case CIPSO_V4_MAP_PASS: 768 return 0; 769 case CIPSO_V4_MAP_TRANS: 770 cipso_cat_size = doi_def->map.std->cat.cipso_size; 771 cipso_array = doi_def->map.std->cat.cipso; 772 for (;;) { 773 cat = netlbl_bitmap_walk(bitmap, 774 bitmap_len_bits, 775 cat + 1, 776 1); 777 if (cat < 0) 778 break; 779 if (cat >= cipso_cat_size || 780 cipso_array[cat] >= CIPSO_V4_INV_CAT) 781 return -EFAULT; 782 } 783 784 if (cat == -1) 785 return 0; 786 break; 787 } 788 789 return -EFAULT; 790 } 791 792 /** 793 * cipso_v4_map_cat_rbm_hton - Perform a category mapping from host to network 794 * @doi_def: the DOI definition 795 * @secattr: the security attributes 796 * @net_cat: the zero'd out category bitmap in network/CIPSO format 797 * @net_cat_len: the length of the CIPSO bitmap in bytes 798 * 799 * Description: 800 * Perform a label mapping to translate a local MLS category bitmap to the 801 * correct CIPSO bitmap using the given DOI definition. Returns the minimum 802 * size in bytes of the network bitmap on success, negative values otherwise. 803 * 804 */ 805 static int cipso_v4_map_cat_rbm_hton(const struct cipso_v4_doi *doi_def, 806 const struct netlbl_lsm_secattr *secattr, 807 unsigned char *net_cat, 808 u32 net_cat_len) 809 { 810 int host_spot = -1; 811 u32 net_spot = CIPSO_V4_INV_CAT; 812 u32 net_spot_max = 0; 813 u32 net_clen_bits = net_cat_len * 8; 814 u32 host_cat_size = 0; 815 u32 *host_cat_array = NULL; 816 817 if (doi_def->type == CIPSO_V4_MAP_TRANS) { 818 host_cat_size = doi_def->map.std->cat.local_size; 819 host_cat_array = doi_def->map.std->cat.local; 820 } 821 822 for (;;) { 823 host_spot = netlbl_catmap_walk(secattr->attr.mls.cat, 824 host_spot + 1); 825 if (host_spot < 0) 826 break; 827 828 switch (doi_def->type) { 829 case CIPSO_V4_MAP_PASS: 830 net_spot = host_spot; 831 break; 832 case CIPSO_V4_MAP_TRANS: 833 if (host_spot >= host_cat_size) 834 return -EPERM; 835 net_spot = host_cat_array[host_spot]; 836 if (net_spot >= CIPSO_V4_INV_CAT) 837 return -EPERM; 838 break; 839 } 840 if (net_spot >= net_clen_bits) 841 return -ENOSPC; 842 netlbl_bitmap_setbit(net_cat, net_spot, 1); 843 844 if (net_spot > net_spot_max) 845 net_spot_max = net_spot; 846 } 847 848 if (++net_spot_max % 8) 849 return net_spot_max / 8 + 1; 850 return net_spot_max / 8; 851 } 852 853 /** 854 * cipso_v4_map_cat_rbm_ntoh - Perform a category mapping from network to host 855 * @doi_def: the DOI definition 856 * @net_cat: the category bitmap in network/CIPSO format 857 * @net_cat_len: the length of the CIPSO bitmap in bytes 858 * @secattr: the security attributes 859 * 860 * Description: 861 * Perform a label mapping to translate a CIPSO bitmap to the correct local 862 * MLS category bitmap using the given DOI definition. Returns zero on 863 * success, negative values on failure. 864 * 865 */ 866 static int cipso_v4_map_cat_rbm_ntoh(const struct cipso_v4_doi *doi_def, 867 const unsigned char *net_cat, 868 u32 net_cat_len, 869 struct netlbl_lsm_secattr *secattr) 870 { 871 int ret_val; 872 int net_spot = -1; 873 u32 host_spot = CIPSO_V4_INV_CAT; 874 u32 net_clen_bits = net_cat_len * 8; 875 u32 net_cat_size = 0; 876 u32 *net_cat_array = NULL; 877 878 if (doi_def->type == CIPSO_V4_MAP_TRANS) { 879 net_cat_size = doi_def->map.std->cat.cipso_size; 880 net_cat_array = doi_def->map.std->cat.cipso; 881 } 882 883 for (;;) { 884 net_spot = netlbl_bitmap_walk(net_cat, 885 net_clen_bits, 886 net_spot + 1, 887 1); 888 if (net_spot < 0) { 889 if (net_spot == -2) 890 return -EFAULT; 891 return 0; 892 } 893 894 switch (doi_def->type) { 895 case CIPSO_V4_MAP_PASS: 896 host_spot = net_spot; 897 break; 898 case CIPSO_V4_MAP_TRANS: 899 if (net_spot >= net_cat_size) 900 return -EPERM; 901 host_spot = net_cat_array[net_spot]; 902 if (host_spot >= CIPSO_V4_INV_CAT) 903 return -EPERM; 904 break; 905 } 906 ret_val = netlbl_catmap_setbit(&secattr->attr.mls.cat, 907 host_spot, 908 GFP_ATOMIC); 909 if (ret_val != 0) 910 return ret_val; 911 } 912 913 return -EINVAL; 914 } 915 916 /** 917 * cipso_v4_map_cat_enum_valid - Checks to see if the categories are valid 918 * @doi_def: the DOI definition 919 * @enumcat: category list 920 * @enumcat_len: length of the category list in bytes 921 * 922 * Description: 923 * Checks the given categories against the given DOI definition and returns a 924 * negative value if any of the categories do not have a valid mapping and a 925 * zero value if all of the categories are valid. 926 * 927 */ 928 static int cipso_v4_map_cat_enum_valid(const struct cipso_v4_doi *doi_def, 929 const unsigned char *enumcat, 930 u32 enumcat_len) 931 { 932 u16 cat; 933 int cat_prev = -1; 934 u32 iter; 935 936 if (doi_def->type != CIPSO_V4_MAP_PASS || enumcat_len & 0x01) 937 return -EFAULT; 938 939 for (iter = 0; iter < enumcat_len; iter += 2) { 940 cat = get_unaligned_be16(&enumcat[iter]); 941 if (cat <= cat_prev) 942 return -EFAULT; 943 cat_prev = cat; 944 } 945 946 return 0; 947 } 948 949 /** 950 * cipso_v4_map_cat_enum_hton - Perform a category mapping from host to network 951 * @doi_def: the DOI definition 952 * @secattr: the security attributes 953 * @net_cat: the zero'd out category list in network/CIPSO format 954 * @net_cat_len: the length of the CIPSO category list in bytes 955 * 956 * Description: 957 * Perform a label mapping to translate a local MLS category bitmap to the 958 * correct CIPSO category list using the given DOI definition. Returns the 959 * size in bytes of the network category bitmap on success, negative values 960 * otherwise. 961 * 962 */ 963 static int cipso_v4_map_cat_enum_hton(const struct cipso_v4_doi *doi_def, 964 const struct netlbl_lsm_secattr *secattr, 965 unsigned char *net_cat, 966 u32 net_cat_len) 967 { 968 int cat = -1; 969 u32 cat_iter = 0; 970 971 for (;;) { 972 cat = netlbl_catmap_walk(secattr->attr.mls.cat, cat + 1); 973 if (cat < 0) 974 break; 975 if ((cat_iter + 2) > net_cat_len) 976 return -ENOSPC; 977 978 *((__be16 *)&net_cat[cat_iter]) = htons(cat); 979 cat_iter += 2; 980 } 981 982 return cat_iter; 983 } 984 985 /** 986 * cipso_v4_map_cat_enum_ntoh - Perform a category mapping from network to host 987 * @doi_def: the DOI definition 988 * @net_cat: the category list in network/CIPSO format 989 * @net_cat_len: the length of the CIPSO bitmap in bytes 990 * @secattr: the security attributes 991 * 992 * Description: 993 * Perform a label mapping to translate a CIPSO category list to the correct 994 * local MLS category bitmap using the given DOI definition. Returns zero on 995 * success, negative values on failure. 996 * 997 */ 998 static int cipso_v4_map_cat_enum_ntoh(const struct cipso_v4_doi *doi_def, 999 const unsigned char *net_cat, 1000 u32 net_cat_len, 1001 struct netlbl_lsm_secattr *secattr) 1002 { 1003 int ret_val; 1004 u32 iter; 1005 1006 for (iter = 0; iter < net_cat_len; iter += 2) { 1007 ret_val = netlbl_catmap_setbit(&secattr->attr.mls.cat, 1008 get_unaligned_be16(&net_cat[iter]), 1009 GFP_ATOMIC); 1010 if (ret_val != 0) 1011 return ret_val; 1012 } 1013 1014 return 0; 1015 } 1016 1017 /** 1018 * cipso_v4_map_cat_rng_valid - Checks to see if the categories are valid 1019 * @doi_def: the DOI definition 1020 * @rngcat: category list 1021 * @rngcat_len: length of the category list in bytes 1022 * 1023 * Description: 1024 * Checks the given categories against the given DOI definition and returns a 1025 * negative value if any of the categories do not have a valid mapping and a 1026 * zero value if all of the categories are valid. 1027 * 1028 */ 1029 static int cipso_v4_map_cat_rng_valid(const struct cipso_v4_doi *doi_def, 1030 const unsigned char *rngcat, 1031 u32 rngcat_len) 1032 { 1033 u16 cat_high; 1034 u16 cat_low; 1035 u32 cat_prev = CIPSO_V4_MAX_REM_CATS + 1; 1036 u32 iter; 1037 1038 if (doi_def->type != CIPSO_V4_MAP_PASS || rngcat_len & 0x01) 1039 return -EFAULT; 1040 1041 for (iter = 0; iter < rngcat_len; iter += 4) { 1042 cat_high = get_unaligned_be16(&rngcat[iter]); 1043 if ((iter + 4) <= rngcat_len) 1044 cat_low = get_unaligned_be16(&rngcat[iter + 2]); 1045 else 1046 cat_low = 0; 1047 1048 if (cat_high > cat_prev) 1049 return -EFAULT; 1050 1051 cat_prev = cat_low; 1052 } 1053 1054 return 0; 1055 } 1056 1057 /** 1058 * cipso_v4_map_cat_rng_hton - Perform a category mapping from host to network 1059 * @doi_def: the DOI definition 1060 * @secattr: the security attributes 1061 * @net_cat: the zero'd out category list in network/CIPSO format 1062 * @net_cat_len: the length of the CIPSO category list in bytes 1063 * 1064 * Description: 1065 * Perform a label mapping to translate a local MLS category bitmap to the 1066 * correct CIPSO category list using the given DOI definition. Returns the 1067 * size in bytes of the network category bitmap on success, negative values 1068 * otherwise. 1069 * 1070 */ 1071 static int cipso_v4_map_cat_rng_hton(const struct cipso_v4_doi *doi_def, 1072 const struct netlbl_lsm_secattr *secattr, 1073 unsigned char *net_cat, 1074 u32 net_cat_len) 1075 { 1076 int iter = -1; 1077 u16 array[CIPSO_V4_TAG_RNG_CAT_MAX * 2]; 1078 u32 array_cnt = 0; 1079 u32 cat_size = 0; 1080 1081 /* make sure we don't overflow the 'array[]' variable */ 1082 if (net_cat_len > 1083 (CIPSO_V4_OPT_LEN_MAX - CIPSO_V4_HDR_LEN - CIPSO_V4_TAG_RNG_BLEN)) 1084 return -ENOSPC; 1085 1086 for (;;) { 1087 iter = netlbl_catmap_walk(secattr->attr.mls.cat, iter + 1); 1088 if (iter < 0) 1089 break; 1090 cat_size += (iter == 0 ? 0 : sizeof(u16)); 1091 if (cat_size > net_cat_len) 1092 return -ENOSPC; 1093 array[array_cnt++] = iter; 1094 1095 iter = netlbl_catmap_walkrng(secattr->attr.mls.cat, iter); 1096 if (iter < 0) 1097 return -EFAULT; 1098 cat_size += sizeof(u16); 1099 if (cat_size > net_cat_len) 1100 return -ENOSPC; 1101 array[array_cnt++] = iter; 1102 } 1103 1104 for (iter = 0; array_cnt > 0;) { 1105 *((__be16 *)&net_cat[iter]) = htons(array[--array_cnt]); 1106 iter += 2; 1107 array_cnt--; 1108 if (array[array_cnt] != 0) { 1109 *((__be16 *)&net_cat[iter]) = htons(array[array_cnt]); 1110 iter += 2; 1111 } 1112 } 1113 1114 return cat_size; 1115 } 1116 1117 /** 1118 * cipso_v4_map_cat_rng_ntoh - Perform a category mapping from network to host 1119 * @doi_def: the DOI definition 1120 * @net_cat: the category list in network/CIPSO format 1121 * @net_cat_len: the length of the CIPSO bitmap in bytes 1122 * @secattr: the security attributes 1123 * 1124 * Description: 1125 * Perform a label mapping to translate a CIPSO category list to the correct 1126 * local MLS category bitmap using the given DOI definition. Returns zero on 1127 * success, negative values on failure. 1128 * 1129 */ 1130 static int cipso_v4_map_cat_rng_ntoh(const struct cipso_v4_doi *doi_def, 1131 const unsigned char *net_cat, 1132 u32 net_cat_len, 1133 struct netlbl_lsm_secattr *secattr) 1134 { 1135 int ret_val; 1136 u32 net_iter; 1137 u16 cat_low; 1138 u16 cat_high; 1139 1140 for (net_iter = 0; net_iter < net_cat_len; net_iter += 4) { 1141 cat_high = get_unaligned_be16(&net_cat[net_iter]); 1142 if ((net_iter + 4) <= net_cat_len) 1143 cat_low = get_unaligned_be16(&net_cat[net_iter + 2]); 1144 else 1145 cat_low = 0; 1146 1147 ret_val = netlbl_catmap_setrng(&secattr->attr.mls.cat, 1148 cat_low, 1149 cat_high, 1150 GFP_ATOMIC); 1151 if (ret_val != 0) 1152 return ret_val; 1153 } 1154 1155 return 0; 1156 } 1157 1158 /* 1159 * Protocol Handling Functions 1160 */ 1161 1162 /** 1163 * cipso_v4_gentag_hdr - Generate a CIPSO option header 1164 * @doi_def: the DOI definition 1165 * @len: the total tag length in bytes, not including this header 1166 * @buf: the CIPSO option buffer 1167 * 1168 * Description: 1169 * Write a CIPSO header into the beginning of @buffer. 1170 * 1171 */ 1172 static void cipso_v4_gentag_hdr(const struct cipso_v4_doi *doi_def, 1173 unsigned char *buf, 1174 u32 len) 1175 { 1176 buf[0] = IPOPT_CIPSO; 1177 buf[1] = CIPSO_V4_HDR_LEN + len; 1178 *(__be32 *)&buf[2] = htonl(doi_def->doi); 1179 } 1180 1181 /** 1182 * cipso_v4_gentag_rbm - Generate a CIPSO restricted bitmap tag (type #1) 1183 * @doi_def: the DOI definition 1184 * @secattr: the security attributes 1185 * @buffer: the option buffer 1186 * @buffer_len: length of buffer in bytes 1187 * 1188 * Description: 1189 * Generate a CIPSO option using the restricted bitmap tag, tag type #1. The 1190 * actual buffer length may be larger than the indicated size due to 1191 * translation between host and network category bitmaps. Returns the size of 1192 * the tag on success, negative values on failure. 1193 * 1194 */ 1195 static int cipso_v4_gentag_rbm(const struct cipso_v4_doi *doi_def, 1196 const struct netlbl_lsm_secattr *secattr, 1197 unsigned char *buffer, 1198 u32 buffer_len) 1199 { 1200 int ret_val; 1201 u32 tag_len; 1202 u32 level; 1203 1204 if ((secattr->flags & NETLBL_SECATTR_MLS_LVL) == 0) 1205 return -EPERM; 1206 1207 ret_val = cipso_v4_map_lvl_hton(doi_def, 1208 secattr->attr.mls.lvl, 1209 &level); 1210 if (ret_val != 0) 1211 return ret_val; 1212 1213 if (secattr->flags & NETLBL_SECATTR_MLS_CAT) { 1214 ret_val = cipso_v4_map_cat_rbm_hton(doi_def, 1215 secattr, 1216 &buffer[4], 1217 buffer_len - 4); 1218 if (ret_val < 0) 1219 return ret_val; 1220 1221 /* This will send packets using the "optimized" format when 1222 * possible as specified in section 3.4.2.6 of the 1223 * CIPSO draft. */ 1224 if (cipso_v4_rbm_optfmt && ret_val > 0 && ret_val <= 10) 1225 tag_len = 14; 1226 else 1227 tag_len = 4 + ret_val; 1228 } else 1229 tag_len = 4; 1230 1231 buffer[0] = CIPSO_V4_TAG_RBITMAP; 1232 buffer[1] = tag_len; 1233 buffer[3] = level; 1234 1235 return tag_len; 1236 } 1237 1238 /** 1239 * cipso_v4_parsetag_rbm - Parse a CIPSO restricted bitmap tag 1240 * @doi_def: the DOI definition 1241 * @tag: the CIPSO tag 1242 * @secattr: the security attributes 1243 * 1244 * Description: 1245 * Parse a CIPSO restricted bitmap tag (tag type #1) and return the security 1246 * attributes in @secattr. Return zero on success, negatives values on 1247 * failure. 1248 * 1249 */ 1250 static int cipso_v4_parsetag_rbm(const struct cipso_v4_doi *doi_def, 1251 const unsigned char *tag, 1252 struct netlbl_lsm_secattr *secattr) 1253 { 1254 int ret_val; 1255 u8 tag_len = tag[1]; 1256 u32 level; 1257 1258 ret_val = cipso_v4_map_lvl_ntoh(doi_def, tag[3], &level); 1259 if (ret_val != 0) 1260 return ret_val; 1261 secattr->attr.mls.lvl = level; 1262 secattr->flags |= NETLBL_SECATTR_MLS_LVL; 1263 1264 if (tag_len > 4) { 1265 ret_val = cipso_v4_map_cat_rbm_ntoh(doi_def, 1266 &tag[4], 1267 tag_len - 4, 1268 secattr); 1269 if (ret_val != 0) { 1270 netlbl_catmap_free(secattr->attr.mls.cat); 1271 return ret_val; 1272 } 1273 1274 secattr->flags |= NETLBL_SECATTR_MLS_CAT; 1275 } 1276 1277 return 0; 1278 } 1279 1280 /** 1281 * cipso_v4_gentag_enum - Generate a CIPSO enumerated tag (type #2) 1282 * @doi_def: the DOI definition 1283 * @secattr: the security attributes 1284 * @buffer: the option buffer 1285 * @buffer_len: length of buffer in bytes 1286 * 1287 * Description: 1288 * Generate a CIPSO option using the enumerated tag, tag type #2. Returns the 1289 * size of the tag on success, negative values on failure. 1290 * 1291 */ 1292 static int cipso_v4_gentag_enum(const struct cipso_v4_doi *doi_def, 1293 const struct netlbl_lsm_secattr *secattr, 1294 unsigned char *buffer, 1295 u32 buffer_len) 1296 { 1297 int ret_val; 1298 u32 tag_len; 1299 u32 level; 1300 1301 if (!(secattr->flags & NETLBL_SECATTR_MLS_LVL)) 1302 return -EPERM; 1303 1304 ret_val = cipso_v4_map_lvl_hton(doi_def, 1305 secattr->attr.mls.lvl, 1306 &level); 1307 if (ret_val != 0) 1308 return ret_val; 1309 1310 if (secattr->flags & NETLBL_SECATTR_MLS_CAT) { 1311 ret_val = cipso_v4_map_cat_enum_hton(doi_def, 1312 secattr, 1313 &buffer[4], 1314 buffer_len - 4); 1315 if (ret_val < 0) 1316 return ret_val; 1317 1318 tag_len = 4 + ret_val; 1319 } else 1320 tag_len = 4; 1321 1322 buffer[0] = CIPSO_V4_TAG_ENUM; 1323 buffer[1] = tag_len; 1324 buffer[3] = level; 1325 1326 return tag_len; 1327 } 1328 1329 /** 1330 * cipso_v4_parsetag_enum - Parse a CIPSO enumerated tag 1331 * @doi_def: the DOI definition 1332 * @tag: the CIPSO tag 1333 * @secattr: the security attributes 1334 * 1335 * Description: 1336 * Parse a CIPSO enumerated tag (tag type #2) and return the security 1337 * attributes in @secattr. Return zero on success, negatives values on 1338 * failure. 1339 * 1340 */ 1341 static int cipso_v4_parsetag_enum(const struct cipso_v4_doi *doi_def, 1342 const unsigned char *tag, 1343 struct netlbl_lsm_secattr *secattr) 1344 { 1345 int ret_val; 1346 u8 tag_len = tag[1]; 1347 u32 level; 1348 1349 ret_val = cipso_v4_map_lvl_ntoh(doi_def, tag[3], &level); 1350 if (ret_val != 0) 1351 return ret_val; 1352 secattr->attr.mls.lvl = level; 1353 secattr->flags |= NETLBL_SECATTR_MLS_LVL; 1354 1355 if (tag_len > 4) { 1356 ret_val = cipso_v4_map_cat_enum_ntoh(doi_def, 1357 &tag[4], 1358 tag_len - 4, 1359 secattr); 1360 if (ret_val != 0) { 1361 netlbl_catmap_free(secattr->attr.mls.cat); 1362 return ret_val; 1363 } 1364 1365 secattr->flags |= NETLBL_SECATTR_MLS_CAT; 1366 } 1367 1368 return 0; 1369 } 1370 1371 /** 1372 * cipso_v4_gentag_rng - Generate a CIPSO ranged tag (type #5) 1373 * @doi_def: the DOI definition 1374 * @secattr: the security attributes 1375 * @buffer: the option buffer 1376 * @buffer_len: length of buffer in bytes 1377 * 1378 * Description: 1379 * Generate a CIPSO option using the ranged tag, tag type #5. Returns the 1380 * size of the tag on success, negative values on failure. 1381 * 1382 */ 1383 static int cipso_v4_gentag_rng(const struct cipso_v4_doi *doi_def, 1384 const struct netlbl_lsm_secattr *secattr, 1385 unsigned char *buffer, 1386 u32 buffer_len) 1387 { 1388 int ret_val; 1389 u32 tag_len; 1390 u32 level; 1391 1392 if (!(secattr->flags & NETLBL_SECATTR_MLS_LVL)) 1393 return -EPERM; 1394 1395 ret_val = cipso_v4_map_lvl_hton(doi_def, 1396 secattr->attr.mls.lvl, 1397 &level); 1398 if (ret_val != 0) 1399 return ret_val; 1400 1401 if (secattr->flags & NETLBL_SECATTR_MLS_CAT) { 1402 ret_val = cipso_v4_map_cat_rng_hton(doi_def, 1403 secattr, 1404 &buffer[4], 1405 buffer_len - 4); 1406 if (ret_val < 0) 1407 return ret_val; 1408 1409 tag_len = 4 + ret_val; 1410 } else 1411 tag_len = 4; 1412 1413 buffer[0] = CIPSO_V4_TAG_RANGE; 1414 buffer[1] = tag_len; 1415 buffer[3] = level; 1416 1417 return tag_len; 1418 } 1419 1420 /** 1421 * cipso_v4_parsetag_rng - Parse a CIPSO ranged tag 1422 * @doi_def: the DOI definition 1423 * @tag: the CIPSO tag 1424 * @secattr: the security attributes 1425 * 1426 * Description: 1427 * Parse a CIPSO ranged tag (tag type #5) and return the security attributes 1428 * in @secattr. Return zero on success, negatives values on failure. 1429 * 1430 */ 1431 static int cipso_v4_parsetag_rng(const struct cipso_v4_doi *doi_def, 1432 const unsigned char *tag, 1433 struct netlbl_lsm_secattr *secattr) 1434 { 1435 int ret_val; 1436 u8 tag_len = tag[1]; 1437 u32 level; 1438 1439 ret_val = cipso_v4_map_lvl_ntoh(doi_def, tag[3], &level); 1440 if (ret_val != 0) 1441 return ret_val; 1442 secattr->attr.mls.lvl = level; 1443 secattr->flags |= NETLBL_SECATTR_MLS_LVL; 1444 1445 if (tag_len > 4) { 1446 ret_val = cipso_v4_map_cat_rng_ntoh(doi_def, 1447 &tag[4], 1448 tag_len - 4, 1449 secattr); 1450 if (ret_val != 0) { 1451 netlbl_catmap_free(secattr->attr.mls.cat); 1452 return ret_val; 1453 } 1454 1455 secattr->flags |= NETLBL_SECATTR_MLS_CAT; 1456 } 1457 1458 return 0; 1459 } 1460 1461 /** 1462 * cipso_v4_gentag_loc - Generate a CIPSO local tag (non-standard) 1463 * @doi_def: the DOI definition 1464 * @secattr: the security attributes 1465 * @buffer: the option buffer 1466 * @buffer_len: length of buffer in bytes 1467 * 1468 * Description: 1469 * Generate a CIPSO option using the local tag. Returns the size of the tag 1470 * on success, negative values on failure. 1471 * 1472 */ 1473 static int cipso_v4_gentag_loc(const struct cipso_v4_doi *doi_def, 1474 const struct netlbl_lsm_secattr *secattr, 1475 unsigned char *buffer, 1476 u32 buffer_len) 1477 { 1478 if (!(secattr->flags & NETLBL_SECATTR_SECID)) 1479 return -EPERM; 1480 1481 buffer[0] = CIPSO_V4_TAG_LOCAL; 1482 buffer[1] = CIPSO_V4_TAG_LOC_BLEN; 1483 *(u32 *)&buffer[2] = secattr->attr.secid; 1484 1485 return CIPSO_V4_TAG_LOC_BLEN; 1486 } 1487 1488 /** 1489 * cipso_v4_parsetag_loc - Parse a CIPSO local tag 1490 * @doi_def: the DOI definition 1491 * @tag: the CIPSO tag 1492 * @secattr: the security attributes 1493 * 1494 * Description: 1495 * Parse a CIPSO local tag and return the security attributes in @secattr. 1496 * Return zero on success, negatives values on failure. 1497 * 1498 */ 1499 static int cipso_v4_parsetag_loc(const struct cipso_v4_doi *doi_def, 1500 const unsigned char *tag, 1501 struct netlbl_lsm_secattr *secattr) 1502 { 1503 secattr->attr.secid = *(u32 *)&tag[2]; 1504 secattr->flags |= NETLBL_SECATTR_SECID; 1505 1506 return 0; 1507 } 1508 1509 /** 1510 * cipso_v4_optptr - Find the CIPSO option in the packet 1511 * @skb: the packet 1512 * 1513 * Description: 1514 * Parse the packet's IP header looking for a CIPSO option. Returns a pointer 1515 * to the start of the CIPSO option on success, NULL if one if not found. 1516 * 1517 */ 1518 unsigned char *cipso_v4_optptr(const struct sk_buff *skb) 1519 { 1520 const struct iphdr *iph = ip_hdr(skb); 1521 unsigned char *optptr = (unsigned char *)&(ip_hdr(skb)[1]); 1522 int optlen; 1523 int taglen; 1524 1525 for (optlen = iph->ihl*4 - sizeof(struct iphdr); optlen > 0; ) { 1526 if (optptr[0] == IPOPT_CIPSO) 1527 return optptr; 1528 taglen = optptr[1]; 1529 optlen -= taglen; 1530 optptr += taglen; 1531 } 1532 1533 return NULL; 1534 } 1535 1536 /** 1537 * cipso_v4_validate - Validate a CIPSO option 1538 * @option: the start of the option, on error it is set to point to the error 1539 * 1540 * Description: 1541 * This routine is called to validate a CIPSO option, it checks all of the 1542 * fields to ensure that they are at least valid, see the draft snippet below 1543 * for details. If the option is valid then a zero value is returned and 1544 * the value of @option is unchanged. If the option is invalid then a 1545 * non-zero value is returned and @option is adjusted to point to the 1546 * offending portion of the option. From the IETF draft ... 1547 * 1548 * "If any field within the CIPSO options, such as the DOI identifier, is not 1549 * recognized the IP datagram is discarded and an ICMP 'parameter problem' 1550 * (type 12) is generated and returned. The ICMP code field is set to 'bad 1551 * parameter' (code 0) and the pointer is set to the start of the CIPSO field 1552 * that is unrecognized." 1553 * 1554 */ 1555 int cipso_v4_validate(const struct sk_buff *skb, unsigned char **option) 1556 { 1557 unsigned char *opt = *option; 1558 unsigned char *tag; 1559 unsigned char opt_iter; 1560 unsigned char err_offset = 0; 1561 u8 opt_len; 1562 u8 tag_len; 1563 struct cipso_v4_doi *doi_def = NULL; 1564 u32 tag_iter; 1565 1566 /* caller already checks for length values that are too large */ 1567 opt_len = opt[1]; 1568 if (opt_len < 8) { 1569 err_offset = 1; 1570 goto validate_return; 1571 } 1572 1573 rcu_read_lock(); 1574 doi_def = cipso_v4_doi_search(get_unaligned_be32(&opt[2])); 1575 if (!doi_def) { 1576 err_offset = 2; 1577 goto validate_return_locked; 1578 } 1579 1580 opt_iter = CIPSO_V4_HDR_LEN; 1581 tag = opt + opt_iter; 1582 while (opt_iter < opt_len) { 1583 for (tag_iter = 0; doi_def->tags[tag_iter] != tag[0];) 1584 if (doi_def->tags[tag_iter] == CIPSO_V4_TAG_INVALID || 1585 ++tag_iter == CIPSO_V4_TAG_MAXCNT) { 1586 err_offset = opt_iter; 1587 goto validate_return_locked; 1588 } 1589 1590 tag_len = tag[1]; 1591 if (tag_len > (opt_len - opt_iter)) { 1592 err_offset = opt_iter + 1; 1593 goto validate_return_locked; 1594 } 1595 1596 switch (tag[0]) { 1597 case CIPSO_V4_TAG_RBITMAP: 1598 if (tag_len < CIPSO_V4_TAG_RBM_BLEN) { 1599 err_offset = opt_iter + 1; 1600 goto validate_return_locked; 1601 } 1602 1603 /* We are already going to do all the verification 1604 * necessary at the socket layer so from our point of 1605 * view it is safe to turn these checks off (and less 1606 * work), however, the CIPSO draft says we should do 1607 * all the CIPSO validations here but it doesn't 1608 * really specify _exactly_ what we need to validate 1609 * ... so, just make it a sysctl tunable. */ 1610 if (cipso_v4_rbm_strictvalid) { 1611 if (cipso_v4_map_lvl_valid(doi_def, 1612 tag[3]) < 0) { 1613 err_offset = opt_iter + 3; 1614 goto validate_return_locked; 1615 } 1616 if (tag_len > CIPSO_V4_TAG_RBM_BLEN && 1617 cipso_v4_map_cat_rbm_valid(doi_def, 1618 &tag[4], 1619 tag_len - 4) < 0) { 1620 err_offset = opt_iter + 4; 1621 goto validate_return_locked; 1622 } 1623 } 1624 break; 1625 case CIPSO_V4_TAG_ENUM: 1626 if (tag_len < CIPSO_V4_TAG_ENUM_BLEN) { 1627 err_offset = opt_iter + 1; 1628 goto validate_return_locked; 1629 } 1630 1631 if (cipso_v4_map_lvl_valid(doi_def, 1632 tag[3]) < 0) { 1633 err_offset = opt_iter + 3; 1634 goto validate_return_locked; 1635 } 1636 if (tag_len > CIPSO_V4_TAG_ENUM_BLEN && 1637 cipso_v4_map_cat_enum_valid(doi_def, 1638 &tag[4], 1639 tag_len - 4) < 0) { 1640 err_offset = opt_iter + 4; 1641 goto validate_return_locked; 1642 } 1643 break; 1644 case CIPSO_V4_TAG_RANGE: 1645 if (tag_len < CIPSO_V4_TAG_RNG_BLEN) { 1646 err_offset = opt_iter + 1; 1647 goto validate_return_locked; 1648 } 1649 1650 if (cipso_v4_map_lvl_valid(doi_def, 1651 tag[3]) < 0) { 1652 err_offset = opt_iter + 3; 1653 goto validate_return_locked; 1654 } 1655 if (tag_len > CIPSO_V4_TAG_RNG_BLEN && 1656 cipso_v4_map_cat_rng_valid(doi_def, 1657 &tag[4], 1658 tag_len - 4) < 0) { 1659 err_offset = opt_iter + 4; 1660 goto validate_return_locked; 1661 } 1662 break; 1663 case CIPSO_V4_TAG_LOCAL: 1664 /* This is a non-standard tag that we only allow for 1665 * local connections, so if the incoming interface is 1666 * not the loopback device drop the packet. Further, 1667 * there is no legitimate reason for setting this from 1668 * userspace so reject it if skb is NULL. */ 1669 if (!skb || !(skb->dev->flags & IFF_LOOPBACK)) { 1670 err_offset = opt_iter; 1671 goto validate_return_locked; 1672 } 1673 if (tag_len != CIPSO_V4_TAG_LOC_BLEN) { 1674 err_offset = opt_iter + 1; 1675 goto validate_return_locked; 1676 } 1677 break; 1678 default: 1679 err_offset = opt_iter; 1680 goto validate_return_locked; 1681 } 1682 1683 tag += tag_len; 1684 opt_iter += tag_len; 1685 } 1686 1687 validate_return_locked: 1688 rcu_read_unlock(); 1689 validate_return: 1690 *option = opt + err_offset; 1691 return err_offset; 1692 } 1693 1694 /** 1695 * cipso_v4_error - Send the correct response for a bad packet 1696 * @skb: the packet 1697 * @error: the error code 1698 * @gateway: CIPSO gateway flag 1699 * 1700 * Description: 1701 * Based on the error code given in @error, send an ICMP error message back to 1702 * the originating host. From the IETF draft ... 1703 * 1704 * "If the contents of the CIPSO [option] are valid but the security label is 1705 * outside of the configured host or port label range, the datagram is 1706 * discarded and an ICMP 'destination unreachable' (type 3) is generated and 1707 * returned. The code field of the ICMP is set to 'communication with 1708 * destination network administratively prohibited' (code 9) or to 1709 * 'communication with destination host administratively prohibited' 1710 * (code 10). The value of the code is dependent on whether the originator 1711 * of the ICMP message is acting as a CIPSO host or a CIPSO gateway. The 1712 * recipient of the ICMP message MUST be able to handle either value. The 1713 * same procedure is performed if a CIPSO [option] can not be added to an 1714 * IP packet because it is too large to fit in the IP options area." 1715 * 1716 * "If the error is triggered by receipt of an ICMP message, the message is 1717 * discarded and no response is permitted (consistent with general ICMP 1718 * processing rules)." 1719 * 1720 */ 1721 void cipso_v4_error(struct sk_buff *skb, int error, u32 gateway) 1722 { 1723 if (ip_hdr(skb)->protocol == IPPROTO_ICMP || error != -EACCES) 1724 return; 1725 1726 if (gateway) 1727 icmp_send(skb, ICMP_DEST_UNREACH, ICMP_NET_ANO, 0); 1728 else 1729 icmp_send(skb, ICMP_DEST_UNREACH, ICMP_HOST_ANO, 0); 1730 } 1731 1732 /** 1733 * cipso_v4_genopt - Generate a CIPSO option 1734 * @buf: the option buffer 1735 * @buf_len: the size of opt_buf 1736 * @doi_def: the CIPSO DOI to use 1737 * @secattr: the security attributes 1738 * 1739 * Description: 1740 * Generate a CIPSO option using the DOI definition and security attributes 1741 * passed to the function. Returns the length of the option on success and 1742 * negative values on failure. 1743 * 1744 */ 1745 static int cipso_v4_genopt(unsigned char *buf, u32 buf_len, 1746 const struct cipso_v4_doi *doi_def, 1747 const struct netlbl_lsm_secattr *secattr) 1748 { 1749 int ret_val; 1750 u32 iter; 1751 1752 if (buf_len <= CIPSO_V4_HDR_LEN) 1753 return -ENOSPC; 1754 1755 /* XXX - This code assumes only one tag per CIPSO option which isn't 1756 * really a good assumption to make but since we only support the MAC 1757 * tags right now it is a safe assumption. */ 1758 iter = 0; 1759 do { 1760 memset(buf, 0, buf_len); 1761 switch (doi_def->tags[iter]) { 1762 case CIPSO_V4_TAG_RBITMAP: 1763 ret_val = cipso_v4_gentag_rbm(doi_def, 1764 secattr, 1765 &buf[CIPSO_V4_HDR_LEN], 1766 buf_len - CIPSO_V4_HDR_LEN); 1767 break; 1768 case CIPSO_V4_TAG_ENUM: 1769 ret_val = cipso_v4_gentag_enum(doi_def, 1770 secattr, 1771 &buf[CIPSO_V4_HDR_LEN], 1772 buf_len - CIPSO_V4_HDR_LEN); 1773 break; 1774 case CIPSO_V4_TAG_RANGE: 1775 ret_val = cipso_v4_gentag_rng(doi_def, 1776 secattr, 1777 &buf[CIPSO_V4_HDR_LEN], 1778 buf_len - CIPSO_V4_HDR_LEN); 1779 break; 1780 case CIPSO_V4_TAG_LOCAL: 1781 ret_val = cipso_v4_gentag_loc(doi_def, 1782 secattr, 1783 &buf[CIPSO_V4_HDR_LEN], 1784 buf_len - CIPSO_V4_HDR_LEN); 1785 break; 1786 default: 1787 return -EPERM; 1788 } 1789 1790 iter++; 1791 } while (ret_val < 0 && 1792 iter < CIPSO_V4_TAG_MAXCNT && 1793 doi_def->tags[iter] != CIPSO_V4_TAG_INVALID); 1794 if (ret_val < 0) 1795 return ret_val; 1796 cipso_v4_gentag_hdr(doi_def, buf, ret_val); 1797 return CIPSO_V4_HDR_LEN + ret_val; 1798 } 1799 1800 /** 1801 * cipso_v4_sock_setattr - Add a CIPSO option to a socket 1802 * @sk: the socket 1803 * @doi_def: the CIPSO DOI to use 1804 * @secattr: the specific security attributes of the socket 1805 * 1806 * Description: 1807 * Set the CIPSO option on the given socket using the DOI definition and 1808 * security attributes passed to the function. This function requires 1809 * exclusive access to @sk, which means it either needs to be in the 1810 * process of being created or locked. Returns zero on success and negative 1811 * values on failure. 1812 * 1813 */ 1814 int cipso_v4_sock_setattr(struct sock *sk, 1815 const struct cipso_v4_doi *doi_def, 1816 const struct netlbl_lsm_secattr *secattr) 1817 { 1818 int ret_val = -EPERM; 1819 unsigned char *buf = NULL; 1820 u32 buf_len; 1821 u32 opt_len; 1822 struct ip_options_rcu *old, *opt = NULL; 1823 struct inet_sock *sk_inet; 1824 struct inet_connection_sock *sk_conn; 1825 1826 /* In the case of sock_create_lite(), the sock->sk field is not 1827 * defined yet but it is not a problem as the only users of these 1828 * "lite" PF_INET sockets are functions which do an accept() call 1829 * afterwards so we will label the socket as part of the accept(). */ 1830 if (!sk) 1831 return 0; 1832 1833 /* We allocate the maximum CIPSO option size here so we are probably 1834 * being a little wasteful, but it makes our life _much_ easier later 1835 * on and after all we are only talking about 40 bytes. */ 1836 buf_len = CIPSO_V4_OPT_LEN_MAX; 1837 buf = kmalloc(buf_len, GFP_ATOMIC); 1838 if (!buf) { 1839 ret_val = -ENOMEM; 1840 goto socket_setattr_failure; 1841 } 1842 1843 ret_val = cipso_v4_genopt(buf, buf_len, doi_def, secattr); 1844 if (ret_val < 0) 1845 goto socket_setattr_failure; 1846 buf_len = ret_val; 1847 1848 /* We can't use ip_options_get() directly because it makes a call to 1849 * ip_options_get_alloc() which allocates memory with GFP_KERNEL and 1850 * we won't always have CAP_NET_RAW even though we _always_ want to 1851 * set the IPOPT_CIPSO option. */ 1852 opt_len = (buf_len + 3) & ~3; 1853 opt = kzalloc(sizeof(*opt) + opt_len, GFP_ATOMIC); 1854 if (!opt) { 1855 ret_val = -ENOMEM; 1856 goto socket_setattr_failure; 1857 } 1858 memcpy(opt->opt.__data, buf, buf_len); 1859 opt->opt.optlen = opt_len; 1860 opt->opt.cipso = sizeof(struct iphdr); 1861 kfree(buf); 1862 buf = NULL; 1863 1864 sk_inet = inet_sk(sk); 1865 1866 old = rcu_dereference_protected(sk_inet->inet_opt, 1867 lockdep_sock_is_held(sk)); 1868 if (sk_inet->is_icsk) { 1869 sk_conn = inet_csk(sk); 1870 if (old) 1871 sk_conn->icsk_ext_hdr_len -= old->opt.optlen; 1872 sk_conn->icsk_ext_hdr_len += opt->opt.optlen; 1873 sk_conn->icsk_sync_mss(sk, sk_conn->icsk_pmtu_cookie); 1874 } 1875 rcu_assign_pointer(sk_inet->inet_opt, opt); 1876 if (old) 1877 kfree_rcu(old, rcu); 1878 1879 return 0; 1880 1881 socket_setattr_failure: 1882 kfree(buf); 1883 kfree(opt); 1884 return ret_val; 1885 } 1886 1887 /** 1888 * cipso_v4_req_setattr - Add a CIPSO option to a connection request socket 1889 * @req: the connection request socket 1890 * @doi_def: the CIPSO DOI to use 1891 * @secattr: the specific security attributes of the socket 1892 * 1893 * Description: 1894 * Set the CIPSO option on the given socket using the DOI definition and 1895 * security attributes passed to the function. Returns zero on success and 1896 * negative values on failure. 1897 * 1898 */ 1899 int cipso_v4_req_setattr(struct request_sock *req, 1900 const struct cipso_v4_doi *doi_def, 1901 const struct netlbl_lsm_secattr *secattr) 1902 { 1903 int ret_val = -EPERM; 1904 unsigned char *buf = NULL; 1905 u32 buf_len; 1906 u32 opt_len; 1907 struct ip_options_rcu *opt = NULL; 1908 struct inet_request_sock *req_inet; 1909 1910 /* We allocate the maximum CIPSO option size here so we are probably 1911 * being a little wasteful, but it makes our life _much_ easier later 1912 * on and after all we are only talking about 40 bytes. */ 1913 buf_len = CIPSO_V4_OPT_LEN_MAX; 1914 buf = kmalloc(buf_len, GFP_ATOMIC); 1915 if (!buf) { 1916 ret_val = -ENOMEM; 1917 goto req_setattr_failure; 1918 } 1919 1920 ret_val = cipso_v4_genopt(buf, buf_len, doi_def, secattr); 1921 if (ret_val < 0) 1922 goto req_setattr_failure; 1923 buf_len = ret_val; 1924 1925 /* We can't use ip_options_get() directly because it makes a call to 1926 * ip_options_get_alloc() which allocates memory with GFP_KERNEL and 1927 * we won't always have CAP_NET_RAW even though we _always_ want to 1928 * set the IPOPT_CIPSO option. */ 1929 opt_len = (buf_len + 3) & ~3; 1930 opt = kzalloc(sizeof(*opt) + opt_len, GFP_ATOMIC); 1931 if (!opt) { 1932 ret_val = -ENOMEM; 1933 goto req_setattr_failure; 1934 } 1935 memcpy(opt->opt.__data, buf, buf_len); 1936 opt->opt.optlen = opt_len; 1937 opt->opt.cipso = sizeof(struct iphdr); 1938 kfree(buf); 1939 buf = NULL; 1940 1941 req_inet = inet_rsk(req); 1942 opt = xchg(&req_inet->opt, opt); 1943 if (opt) 1944 kfree_rcu(opt, rcu); 1945 1946 return 0; 1947 1948 req_setattr_failure: 1949 kfree(buf); 1950 kfree(opt); 1951 return ret_val; 1952 } 1953 1954 /** 1955 * cipso_v4_delopt - Delete the CIPSO option from a set of IP options 1956 * @opt_ptr: IP option pointer 1957 * 1958 * Description: 1959 * Deletes the CIPSO IP option from a set of IP options and makes the necessary 1960 * adjustments to the IP option structure. Returns zero on success, negative 1961 * values on failure. 1962 * 1963 */ 1964 static int cipso_v4_delopt(struct ip_options_rcu **opt_ptr) 1965 { 1966 int hdr_delta = 0; 1967 struct ip_options_rcu *opt = *opt_ptr; 1968 1969 if (opt->opt.srr || opt->opt.rr || opt->opt.ts || opt->opt.router_alert) { 1970 u8 cipso_len; 1971 u8 cipso_off; 1972 unsigned char *cipso_ptr; 1973 int iter; 1974 int optlen_new; 1975 1976 cipso_off = opt->opt.cipso - sizeof(struct iphdr); 1977 cipso_ptr = &opt->opt.__data[cipso_off]; 1978 cipso_len = cipso_ptr[1]; 1979 1980 if (opt->opt.srr > opt->opt.cipso) 1981 opt->opt.srr -= cipso_len; 1982 if (opt->opt.rr > opt->opt.cipso) 1983 opt->opt.rr -= cipso_len; 1984 if (opt->opt.ts > opt->opt.cipso) 1985 opt->opt.ts -= cipso_len; 1986 if (opt->opt.router_alert > opt->opt.cipso) 1987 opt->opt.router_alert -= cipso_len; 1988 opt->opt.cipso = 0; 1989 1990 memmove(cipso_ptr, cipso_ptr + cipso_len, 1991 opt->opt.optlen - cipso_off - cipso_len); 1992 1993 /* determining the new total option length is tricky because of 1994 * the padding necessary, the only thing i can think to do at 1995 * this point is walk the options one-by-one, skipping the 1996 * padding at the end to determine the actual option size and 1997 * from there we can determine the new total option length */ 1998 iter = 0; 1999 optlen_new = 0; 2000 while (iter < opt->opt.optlen) 2001 if (opt->opt.__data[iter] != IPOPT_NOP) { 2002 iter += opt->opt.__data[iter + 1]; 2003 optlen_new = iter; 2004 } else 2005 iter++; 2006 hdr_delta = opt->opt.optlen; 2007 opt->opt.optlen = (optlen_new + 3) & ~3; 2008 hdr_delta -= opt->opt.optlen; 2009 } else { 2010 /* only the cipso option was present on the socket so we can 2011 * remove the entire option struct */ 2012 *opt_ptr = NULL; 2013 hdr_delta = opt->opt.optlen; 2014 kfree_rcu(opt, rcu); 2015 } 2016 2017 return hdr_delta; 2018 } 2019 2020 /** 2021 * cipso_v4_sock_delattr - Delete the CIPSO option from a socket 2022 * @sk: the socket 2023 * 2024 * Description: 2025 * Removes the CIPSO option from a socket, if present. 2026 * 2027 */ 2028 void cipso_v4_sock_delattr(struct sock *sk) 2029 { 2030 int hdr_delta; 2031 struct ip_options_rcu *opt; 2032 struct inet_sock *sk_inet; 2033 2034 sk_inet = inet_sk(sk); 2035 opt = rcu_dereference_protected(sk_inet->inet_opt, 1); 2036 if (!opt || opt->opt.cipso == 0) 2037 return; 2038 2039 hdr_delta = cipso_v4_delopt(&sk_inet->inet_opt); 2040 if (sk_inet->is_icsk && hdr_delta > 0) { 2041 struct inet_connection_sock *sk_conn = inet_csk(sk); 2042 sk_conn->icsk_ext_hdr_len -= hdr_delta; 2043 sk_conn->icsk_sync_mss(sk, sk_conn->icsk_pmtu_cookie); 2044 } 2045 } 2046 2047 /** 2048 * cipso_v4_req_delattr - Delete the CIPSO option from a request socket 2049 * @reg: the request socket 2050 * 2051 * Description: 2052 * Removes the CIPSO option from a request socket, if present. 2053 * 2054 */ 2055 void cipso_v4_req_delattr(struct request_sock *req) 2056 { 2057 struct ip_options_rcu *opt; 2058 struct inet_request_sock *req_inet; 2059 2060 req_inet = inet_rsk(req); 2061 opt = req_inet->opt; 2062 if (!opt || opt->opt.cipso == 0) 2063 return; 2064 2065 cipso_v4_delopt(&req_inet->opt); 2066 } 2067 2068 /** 2069 * cipso_v4_getattr - Helper function for the cipso_v4_*_getattr functions 2070 * @cipso: the CIPSO v4 option 2071 * @secattr: the security attributes 2072 * 2073 * Description: 2074 * Inspect @cipso and return the security attributes in @secattr. Returns zero 2075 * on success and negative values on failure. 2076 * 2077 */ 2078 int cipso_v4_getattr(const unsigned char *cipso, 2079 struct netlbl_lsm_secattr *secattr) 2080 { 2081 int ret_val = -ENOMSG; 2082 u32 doi; 2083 struct cipso_v4_doi *doi_def; 2084 2085 if (cipso_v4_cache_check(cipso, cipso[1], secattr) == 0) 2086 return 0; 2087 2088 doi = get_unaligned_be32(&cipso[2]); 2089 rcu_read_lock(); 2090 doi_def = cipso_v4_doi_search(doi); 2091 if (!doi_def) 2092 goto getattr_return; 2093 /* XXX - This code assumes only one tag per CIPSO option which isn't 2094 * really a good assumption to make but since we only support the MAC 2095 * tags right now it is a safe assumption. */ 2096 switch (cipso[6]) { 2097 case CIPSO_V4_TAG_RBITMAP: 2098 ret_val = cipso_v4_parsetag_rbm(doi_def, &cipso[6], secattr); 2099 break; 2100 case CIPSO_V4_TAG_ENUM: 2101 ret_val = cipso_v4_parsetag_enum(doi_def, &cipso[6], secattr); 2102 break; 2103 case CIPSO_V4_TAG_RANGE: 2104 ret_val = cipso_v4_parsetag_rng(doi_def, &cipso[6], secattr); 2105 break; 2106 case CIPSO_V4_TAG_LOCAL: 2107 ret_val = cipso_v4_parsetag_loc(doi_def, &cipso[6], secattr); 2108 break; 2109 } 2110 if (ret_val == 0) 2111 secattr->type = NETLBL_NLTYPE_CIPSOV4; 2112 2113 getattr_return: 2114 rcu_read_unlock(); 2115 return ret_val; 2116 } 2117 2118 /** 2119 * cipso_v4_sock_getattr - Get the security attributes from a sock 2120 * @sk: the sock 2121 * @secattr: the security attributes 2122 * 2123 * Description: 2124 * Query @sk to see if there is a CIPSO option attached to the sock and if 2125 * there is return the CIPSO security attributes in @secattr. This function 2126 * requires that @sk be locked, or privately held, but it does not do any 2127 * locking itself. Returns zero on success and negative values on failure. 2128 * 2129 */ 2130 int cipso_v4_sock_getattr(struct sock *sk, struct netlbl_lsm_secattr *secattr) 2131 { 2132 struct ip_options_rcu *opt; 2133 int res = -ENOMSG; 2134 2135 rcu_read_lock(); 2136 opt = rcu_dereference(inet_sk(sk)->inet_opt); 2137 if (opt && opt->opt.cipso) 2138 res = cipso_v4_getattr(opt->opt.__data + 2139 opt->opt.cipso - 2140 sizeof(struct iphdr), 2141 secattr); 2142 rcu_read_unlock(); 2143 return res; 2144 } 2145 2146 /** 2147 * cipso_v4_skbuff_setattr - Set the CIPSO option on a packet 2148 * @skb: the packet 2149 * @secattr: the security attributes 2150 * 2151 * Description: 2152 * Set the CIPSO option on the given packet based on the security attributes. 2153 * Returns a pointer to the IP header on success and NULL on failure. 2154 * 2155 */ 2156 int cipso_v4_skbuff_setattr(struct sk_buff *skb, 2157 const struct cipso_v4_doi *doi_def, 2158 const struct netlbl_lsm_secattr *secattr) 2159 { 2160 int ret_val; 2161 struct iphdr *iph; 2162 struct ip_options *opt = &IPCB(skb)->opt; 2163 unsigned char buf[CIPSO_V4_OPT_LEN_MAX]; 2164 u32 buf_len = CIPSO_V4_OPT_LEN_MAX; 2165 u32 opt_len; 2166 int len_delta; 2167 2168 ret_val = cipso_v4_genopt(buf, buf_len, doi_def, secattr); 2169 if (ret_val < 0) 2170 return ret_val; 2171 buf_len = ret_val; 2172 opt_len = (buf_len + 3) & ~3; 2173 2174 /* we overwrite any existing options to ensure that we have enough 2175 * room for the CIPSO option, the reason is that we _need_ to guarantee 2176 * that the security label is applied to the packet - we do the same 2177 * thing when using the socket options and it hasn't caused a problem, 2178 * if we need to we can always revisit this choice later */ 2179 2180 len_delta = opt_len - opt->optlen; 2181 /* if we don't ensure enough headroom we could panic on the skb_push() 2182 * call below so make sure we have enough, we are also "mangling" the 2183 * packet so we should probably do a copy-on-write call anyway */ 2184 ret_val = skb_cow(skb, skb_headroom(skb) + len_delta); 2185 if (ret_val < 0) 2186 return ret_val; 2187 2188 if (len_delta > 0) { 2189 /* we assume that the header + opt->optlen have already been 2190 * "pushed" in ip_options_build() or similar */ 2191 iph = ip_hdr(skb); 2192 skb_push(skb, len_delta); 2193 memmove((char *)iph - len_delta, iph, iph->ihl << 2); 2194 skb_reset_network_header(skb); 2195 iph = ip_hdr(skb); 2196 } else if (len_delta < 0) { 2197 iph = ip_hdr(skb); 2198 memset(iph + 1, IPOPT_NOP, opt->optlen); 2199 } else 2200 iph = ip_hdr(skb); 2201 2202 if (opt->optlen > 0) 2203 memset(opt, 0, sizeof(*opt)); 2204 opt->optlen = opt_len; 2205 opt->cipso = sizeof(struct iphdr); 2206 opt->is_changed = 1; 2207 2208 /* we have to do the following because we are being called from a 2209 * netfilter hook which means the packet already has had the header 2210 * fields populated and the checksum calculated - yes this means we 2211 * are doing more work than needed but we do it to keep the core 2212 * stack clean and tidy */ 2213 memcpy(iph + 1, buf, buf_len); 2214 if (opt_len > buf_len) 2215 memset((char *)(iph + 1) + buf_len, 0, opt_len - buf_len); 2216 if (len_delta != 0) { 2217 iph->ihl = 5 + (opt_len >> 2); 2218 iph->tot_len = htons(skb->len); 2219 } 2220 ip_send_check(iph); 2221 2222 return 0; 2223 } 2224 2225 /** 2226 * cipso_v4_skbuff_delattr - Delete any CIPSO options from a packet 2227 * @skb: the packet 2228 * 2229 * Description: 2230 * Removes any and all CIPSO options from the given packet. Returns zero on 2231 * success, negative values on failure. 2232 * 2233 */ 2234 int cipso_v4_skbuff_delattr(struct sk_buff *skb) 2235 { 2236 int ret_val; 2237 struct iphdr *iph; 2238 struct ip_options *opt = &IPCB(skb)->opt; 2239 unsigned char *cipso_ptr; 2240 2241 if (opt->cipso == 0) 2242 return 0; 2243 2244 /* since we are changing the packet we should make a copy */ 2245 ret_val = skb_cow(skb, skb_headroom(skb)); 2246 if (ret_val < 0) 2247 return ret_val; 2248 2249 /* the easiest thing to do is just replace the cipso option with noop 2250 * options since we don't change the size of the packet, although we 2251 * still need to recalculate the checksum */ 2252 2253 iph = ip_hdr(skb); 2254 cipso_ptr = (unsigned char *)iph + opt->cipso; 2255 memset(cipso_ptr, IPOPT_NOOP, cipso_ptr[1]); 2256 opt->cipso = 0; 2257 opt->is_changed = 1; 2258 2259 ip_send_check(iph); 2260 2261 return 0; 2262 } 2263 2264 /* 2265 * Setup Functions 2266 */ 2267 2268 /** 2269 * cipso_v4_init - Initialize the CIPSO module 2270 * 2271 * Description: 2272 * Initialize the CIPSO module and prepare it for use. Returns zero on success 2273 * and negative values on failure. 2274 * 2275 */ 2276 static int __init cipso_v4_init(void) 2277 { 2278 int ret_val; 2279 2280 ret_val = cipso_v4_cache_init(); 2281 if (ret_val != 0) 2282 panic("Failed to initialize the CIPSO/IPv4 cache (%d)\n", 2283 ret_val); 2284 2285 return 0; 2286 } 2287 2288 subsys_initcall(cipso_v4_init); 2289