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_bitmap_walk - Walk a bitmap looking for a bit 139 * @bitmap: the bitmap 140 * @bitmap_len: length in bits 141 * @offset: starting offset 142 * @state: if non-zero, look for a set (1) bit else look for a cleared (0) bit 143 * 144 * Description: 145 * Starting at @offset, walk the bitmap from left to right until either the 146 * desired bit is found or we reach the end. Return the bit offset, -1 if 147 * not found, or -2 if error. 148 */ 149 static int cipso_v4_bitmap_walk(const unsigned char *bitmap, 150 u32 bitmap_len, 151 u32 offset, 152 u8 state) 153 { 154 u32 bit_spot; 155 u32 byte_offset; 156 unsigned char bitmask; 157 unsigned char byte; 158 159 /* gcc always rounds to zero when doing integer division */ 160 byte_offset = offset / 8; 161 byte = bitmap[byte_offset]; 162 bit_spot = offset; 163 bitmask = 0x80 >> (offset % 8); 164 165 while (bit_spot < bitmap_len) { 166 if ((state && (byte & bitmask) == bitmask) || 167 (state == 0 && (byte & bitmask) == 0)) 168 return bit_spot; 169 170 bit_spot++; 171 bitmask >>= 1; 172 if (bitmask == 0) { 173 byte = bitmap[++byte_offset]; 174 bitmask = 0x80; 175 } 176 } 177 178 return -1; 179 } 180 181 /** 182 * cipso_v4_bitmap_setbit - Sets a single bit in a bitmap 183 * @bitmap: the bitmap 184 * @bit: the bit 185 * @state: if non-zero, set the bit (1) else clear the bit (0) 186 * 187 * Description: 188 * Set a single bit in the bitmask. Returns zero on success, negative values 189 * on error. 190 */ 191 static void cipso_v4_bitmap_setbit(unsigned char *bitmap, 192 u32 bit, 193 u8 state) 194 { 195 u32 byte_spot; 196 u8 bitmask; 197 198 /* gcc always rounds to zero when doing integer division */ 199 byte_spot = bit / 8; 200 bitmask = 0x80 >> (bit % 8); 201 if (state) 202 bitmap[byte_spot] |= bitmask; 203 else 204 bitmap[byte_spot] &= ~bitmask; 205 } 206 207 /** 208 * cipso_v4_cache_entry_free - Frees a cache entry 209 * @entry: the entry to free 210 * 211 * Description: 212 * This function frees the memory associated with a cache entry including the 213 * LSM cache data if there are no longer any users, i.e. reference count == 0. 214 * 215 */ 216 static void cipso_v4_cache_entry_free(struct cipso_v4_map_cache_entry *entry) 217 { 218 if (entry->lsm_data) 219 netlbl_secattr_cache_free(entry->lsm_data); 220 kfree(entry->key); 221 kfree(entry); 222 } 223 224 /** 225 * cipso_v4_map_cache_hash - Hashing function for the CIPSO cache 226 * @key: the hash key 227 * @key_len: the length of the key in bytes 228 * 229 * Description: 230 * The CIPSO tag hashing function. Returns a 32-bit hash value. 231 * 232 */ 233 static u32 cipso_v4_map_cache_hash(const unsigned char *key, u32 key_len) 234 { 235 return jhash(key, key_len, 0); 236 } 237 238 /* 239 * Label Mapping Cache Functions 240 */ 241 242 /** 243 * cipso_v4_cache_init - Initialize the CIPSO cache 244 * 245 * Description: 246 * Initializes the CIPSO label mapping cache, this function should be called 247 * before any of the other functions defined in this file. Returns zero on 248 * success, negative values on error. 249 * 250 */ 251 static int __init cipso_v4_cache_init(void) 252 { 253 u32 iter; 254 255 cipso_v4_cache = kcalloc(CIPSO_V4_CACHE_BUCKETS, 256 sizeof(struct cipso_v4_map_cache_bkt), 257 GFP_KERNEL); 258 if (!cipso_v4_cache) 259 return -ENOMEM; 260 261 for (iter = 0; iter < CIPSO_V4_CACHE_BUCKETS; iter++) { 262 spin_lock_init(&cipso_v4_cache[iter].lock); 263 cipso_v4_cache[iter].size = 0; 264 INIT_LIST_HEAD(&cipso_v4_cache[iter].list); 265 } 266 267 return 0; 268 } 269 270 /** 271 * cipso_v4_cache_invalidate - Invalidates the current CIPSO cache 272 * 273 * Description: 274 * Invalidates and frees any entries in the CIPSO cache. Returns zero on 275 * success and negative values on failure. 276 * 277 */ 278 void cipso_v4_cache_invalidate(void) 279 { 280 struct cipso_v4_map_cache_entry *entry, *tmp_entry; 281 u32 iter; 282 283 for (iter = 0; iter < CIPSO_V4_CACHE_BUCKETS; iter++) { 284 spin_lock_bh(&cipso_v4_cache[iter].lock); 285 list_for_each_entry_safe(entry, 286 tmp_entry, 287 &cipso_v4_cache[iter].list, list) { 288 list_del(&entry->list); 289 cipso_v4_cache_entry_free(entry); 290 } 291 cipso_v4_cache[iter].size = 0; 292 spin_unlock_bh(&cipso_v4_cache[iter].lock); 293 } 294 } 295 296 /** 297 * cipso_v4_cache_check - Check the CIPSO cache for a label mapping 298 * @key: the buffer to check 299 * @key_len: buffer length in bytes 300 * @secattr: the security attribute struct to use 301 * 302 * Description: 303 * This function checks the cache to see if a label mapping already exists for 304 * the given key. If there is a match then the cache is adjusted and the 305 * @secattr struct is populated with the correct LSM security attributes. The 306 * cache is adjusted in the following manner if the entry is not already the 307 * first in the cache bucket: 308 * 309 * 1. The cache entry's activity counter is incremented 310 * 2. The previous (higher ranking) entry's activity counter is decremented 311 * 3. If the difference between the two activity counters is geater than 312 * CIPSO_V4_CACHE_REORDERLIMIT the two entries are swapped 313 * 314 * Returns zero on success, -ENOENT for a cache miss, and other negative values 315 * on error. 316 * 317 */ 318 static int cipso_v4_cache_check(const unsigned char *key, 319 u32 key_len, 320 struct netlbl_lsm_secattr *secattr) 321 { 322 u32 bkt; 323 struct cipso_v4_map_cache_entry *entry; 324 struct cipso_v4_map_cache_entry *prev_entry = NULL; 325 u32 hash; 326 327 if (!cipso_v4_cache_enabled) 328 return -ENOENT; 329 330 hash = cipso_v4_map_cache_hash(key, key_len); 331 bkt = hash & (CIPSO_V4_CACHE_BUCKETS - 1); 332 spin_lock_bh(&cipso_v4_cache[bkt].lock); 333 list_for_each_entry(entry, &cipso_v4_cache[bkt].list, list) { 334 if (entry->hash == hash && 335 entry->key_len == key_len && 336 memcmp(entry->key, key, key_len) == 0) { 337 entry->activity += 1; 338 atomic_inc(&entry->lsm_data->refcount); 339 secattr->cache = entry->lsm_data; 340 secattr->flags |= NETLBL_SECATTR_CACHE; 341 secattr->type = NETLBL_NLTYPE_CIPSOV4; 342 if (!prev_entry) { 343 spin_unlock_bh(&cipso_v4_cache[bkt].lock); 344 return 0; 345 } 346 347 if (prev_entry->activity > 0) 348 prev_entry->activity -= 1; 349 if (entry->activity > prev_entry->activity && 350 entry->activity - prev_entry->activity > 351 CIPSO_V4_CACHE_REORDERLIMIT) { 352 __list_del(entry->list.prev, entry->list.next); 353 __list_add(&entry->list, 354 prev_entry->list.prev, 355 &prev_entry->list); 356 } 357 358 spin_unlock_bh(&cipso_v4_cache[bkt].lock); 359 return 0; 360 } 361 prev_entry = entry; 362 } 363 spin_unlock_bh(&cipso_v4_cache[bkt].lock); 364 365 return -ENOENT; 366 } 367 368 /** 369 * cipso_v4_cache_add - Add an entry to the CIPSO cache 370 * @skb: the packet 371 * @secattr: the packet's security attributes 372 * 373 * Description: 374 * Add a new entry into the CIPSO label mapping cache. Add the new entry to 375 * head of the cache bucket's list, if the cache bucket is out of room remove 376 * the last entry in the list first. It is important to note that there is 377 * currently no checking for duplicate keys. Returns zero on success, 378 * negative values on failure. 379 * 380 */ 381 int cipso_v4_cache_add(const unsigned char *cipso_ptr, 382 const struct netlbl_lsm_secattr *secattr) 383 { 384 int ret_val = -EPERM; 385 u32 bkt; 386 struct cipso_v4_map_cache_entry *entry = NULL; 387 struct cipso_v4_map_cache_entry *old_entry = NULL; 388 u32 cipso_ptr_len; 389 390 if (!cipso_v4_cache_enabled || cipso_v4_cache_bucketsize <= 0) 391 return 0; 392 393 cipso_ptr_len = cipso_ptr[1]; 394 395 entry = kzalloc(sizeof(*entry), GFP_ATOMIC); 396 if (!entry) 397 return -ENOMEM; 398 entry->key = kmemdup(cipso_ptr, cipso_ptr_len, GFP_ATOMIC); 399 if (!entry->key) { 400 ret_val = -ENOMEM; 401 goto cache_add_failure; 402 } 403 entry->key_len = cipso_ptr_len; 404 entry->hash = cipso_v4_map_cache_hash(cipso_ptr, cipso_ptr_len); 405 atomic_inc(&secattr->cache->refcount); 406 entry->lsm_data = secattr->cache; 407 408 bkt = entry->hash & (CIPSO_V4_CACHE_BUCKETS - 1); 409 spin_lock_bh(&cipso_v4_cache[bkt].lock); 410 if (cipso_v4_cache[bkt].size < cipso_v4_cache_bucketsize) { 411 list_add(&entry->list, &cipso_v4_cache[bkt].list); 412 cipso_v4_cache[bkt].size += 1; 413 } else { 414 old_entry = list_entry(cipso_v4_cache[bkt].list.prev, 415 struct cipso_v4_map_cache_entry, list); 416 list_del(&old_entry->list); 417 list_add(&entry->list, &cipso_v4_cache[bkt].list); 418 cipso_v4_cache_entry_free(old_entry); 419 } 420 spin_unlock_bh(&cipso_v4_cache[bkt].lock); 421 422 return 0; 423 424 cache_add_failure: 425 if (entry) 426 cipso_v4_cache_entry_free(entry); 427 return ret_val; 428 } 429 430 /* 431 * DOI List Functions 432 */ 433 434 /** 435 * cipso_v4_doi_search - Searches for a DOI definition 436 * @doi: the DOI to search for 437 * 438 * Description: 439 * Search the DOI definition list for a DOI definition with a DOI value that 440 * matches @doi. The caller is responsible for calling rcu_read_[un]lock(). 441 * Returns a pointer to the DOI definition on success and NULL on failure. 442 */ 443 static struct cipso_v4_doi *cipso_v4_doi_search(u32 doi) 444 { 445 struct cipso_v4_doi *iter; 446 447 list_for_each_entry_rcu(iter, &cipso_v4_doi_list, list) 448 if (iter->doi == doi && atomic_read(&iter->refcount)) 449 return iter; 450 return NULL; 451 } 452 453 /** 454 * cipso_v4_doi_add - Add a new DOI to the CIPSO protocol engine 455 * @doi_def: the DOI structure 456 * @audit_info: NetLabel audit information 457 * 458 * Description: 459 * The caller defines a new DOI for use by the CIPSO engine and calls this 460 * function to add it to the list of acceptable domains. The caller must 461 * ensure that the mapping table specified in @doi_def->map meets all of the 462 * requirements of the mapping type (see cipso_ipv4.h for details). Returns 463 * zero on success and non-zero on failure. 464 * 465 */ 466 int cipso_v4_doi_add(struct cipso_v4_doi *doi_def, 467 struct netlbl_audit *audit_info) 468 { 469 int ret_val = -EINVAL; 470 u32 iter; 471 u32 doi; 472 u32 doi_type; 473 struct audit_buffer *audit_buf; 474 475 doi = doi_def->doi; 476 doi_type = doi_def->type; 477 478 if (doi_def->doi == CIPSO_V4_DOI_UNKNOWN) 479 goto doi_add_return; 480 for (iter = 0; iter < CIPSO_V4_TAG_MAXCNT; iter++) { 481 switch (doi_def->tags[iter]) { 482 case CIPSO_V4_TAG_RBITMAP: 483 break; 484 case CIPSO_V4_TAG_RANGE: 485 case CIPSO_V4_TAG_ENUM: 486 if (doi_def->type != CIPSO_V4_MAP_PASS) 487 goto doi_add_return; 488 break; 489 case CIPSO_V4_TAG_LOCAL: 490 if (doi_def->type != CIPSO_V4_MAP_LOCAL) 491 goto doi_add_return; 492 break; 493 case CIPSO_V4_TAG_INVALID: 494 if (iter == 0) 495 goto doi_add_return; 496 break; 497 default: 498 goto doi_add_return; 499 } 500 } 501 502 atomic_set(&doi_def->refcount, 1); 503 504 spin_lock(&cipso_v4_doi_list_lock); 505 if (cipso_v4_doi_search(doi_def->doi)) { 506 spin_unlock(&cipso_v4_doi_list_lock); 507 ret_val = -EEXIST; 508 goto doi_add_return; 509 } 510 list_add_tail_rcu(&doi_def->list, &cipso_v4_doi_list); 511 spin_unlock(&cipso_v4_doi_list_lock); 512 ret_val = 0; 513 514 doi_add_return: 515 audit_buf = netlbl_audit_start(AUDIT_MAC_CIPSOV4_ADD, audit_info); 516 if (audit_buf) { 517 const char *type_str; 518 switch (doi_type) { 519 case CIPSO_V4_MAP_TRANS: 520 type_str = "trans"; 521 break; 522 case CIPSO_V4_MAP_PASS: 523 type_str = "pass"; 524 break; 525 case CIPSO_V4_MAP_LOCAL: 526 type_str = "local"; 527 break; 528 default: 529 type_str = "(unknown)"; 530 } 531 audit_log_format(audit_buf, 532 " cipso_doi=%u cipso_type=%s res=%u", 533 doi, type_str, ret_val == 0 ? 1 : 0); 534 audit_log_end(audit_buf); 535 } 536 537 return ret_val; 538 } 539 540 /** 541 * cipso_v4_doi_free - Frees a DOI definition 542 * @doi_def: the DOI definition 543 * 544 * Description: 545 * This function frees all of the memory associated with a DOI definition. 546 * 547 */ 548 void cipso_v4_doi_free(struct cipso_v4_doi *doi_def) 549 { 550 if (!doi_def) 551 return; 552 553 switch (doi_def->type) { 554 case CIPSO_V4_MAP_TRANS: 555 kfree(doi_def->map.std->lvl.cipso); 556 kfree(doi_def->map.std->lvl.local); 557 kfree(doi_def->map.std->cat.cipso); 558 kfree(doi_def->map.std->cat.local); 559 break; 560 } 561 kfree(doi_def); 562 } 563 564 /** 565 * cipso_v4_doi_free_rcu - Frees a DOI definition via the RCU pointer 566 * @entry: the entry's RCU field 567 * 568 * Description: 569 * This function is designed to be used as a callback to the call_rcu() 570 * function so that the memory allocated to the DOI definition can be released 571 * safely. 572 * 573 */ 574 static void cipso_v4_doi_free_rcu(struct rcu_head *entry) 575 { 576 struct cipso_v4_doi *doi_def; 577 578 doi_def = container_of(entry, struct cipso_v4_doi, rcu); 579 cipso_v4_doi_free(doi_def); 580 } 581 582 /** 583 * cipso_v4_doi_remove - Remove an existing DOI from the CIPSO protocol engine 584 * @doi: the DOI value 585 * @audit_secid: the LSM secid to use in the audit message 586 * 587 * Description: 588 * Removes a DOI definition from the CIPSO engine. The NetLabel routines will 589 * be called to release their own LSM domain mappings as well as our own 590 * domain list. Returns zero on success and negative values on failure. 591 * 592 */ 593 int cipso_v4_doi_remove(u32 doi, struct netlbl_audit *audit_info) 594 { 595 int ret_val; 596 struct cipso_v4_doi *doi_def; 597 struct audit_buffer *audit_buf; 598 599 spin_lock(&cipso_v4_doi_list_lock); 600 doi_def = cipso_v4_doi_search(doi); 601 if (!doi_def) { 602 spin_unlock(&cipso_v4_doi_list_lock); 603 ret_val = -ENOENT; 604 goto doi_remove_return; 605 } 606 if (!atomic_dec_and_test(&doi_def->refcount)) { 607 spin_unlock(&cipso_v4_doi_list_lock); 608 ret_val = -EBUSY; 609 goto doi_remove_return; 610 } 611 list_del_rcu(&doi_def->list); 612 spin_unlock(&cipso_v4_doi_list_lock); 613 614 cipso_v4_cache_invalidate(); 615 call_rcu(&doi_def->rcu, cipso_v4_doi_free_rcu); 616 ret_val = 0; 617 618 doi_remove_return: 619 audit_buf = netlbl_audit_start(AUDIT_MAC_CIPSOV4_DEL, audit_info); 620 if (audit_buf) { 621 audit_log_format(audit_buf, 622 " cipso_doi=%u res=%u", 623 doi, ret_val == 0 ? 1 : 0); 624 audit_log_end(audit_buf); 625 } 626 627 return ret_val; 628 } 629 630 /** 631 * cipso_v4_doi_getdef - Returns a reference to a valid DOI definition 632 * @doi: the DOI value 633 * 634 * Description: 635 * Searches for a valid DOI definition and if one is found it is returned to 636 * the caller. Otherwise NULL is returned. The caller must ensure that 637 * rcu_read_lock() is held while accessing the returned definition and the DOI 638 * definition reference count is decremented when the caller is done. 639 * 640 */ 641 struct cipso_v4_doi *cipso_v4_doi_getdef(u32 doi) 642 { 643 struct cipso_v4_doi *doi_def; 644 645 rcu_read_lock(); 646 doi_def = cipso_v4_doi_search(doi); 647 if (!doi_def) 648 goto doi_getdef_return; 649 if (!atomic_inc_not_zero(&doi_def->refcount)) 650 doi_def = NULL; 651 652 doi_getdef_return: 653 rcu_read_unlock(); 654 return doi_def; 655 } 656 657 /** 658 * cipso_v4_doi_putdef - Releases a reference for the given DOI definition 659 * @doi_def: the DOI definition 660 * 661 * Description: 662 * Releases a DOI definition reference obtained from cipso_v4_doi_getdef(). 663 * 664 */ 665 void cipso_v4_doi_putdef(struct cipso_v4_doi *doi_def) 666 { 667 if (!doi_def) 668 return; 669 670 if (!atomic_dec_and_test(&doi_def->refcount)) 671 return; 672 spin_lock(&cipso_v4_doi_list_lock); 673 list_del_rcu(&doi_def->list); 674 spin_unlock(&cipso_v4_doi_list_lock); 675 676 cipso_v4_cache_invalidate(); 677 call_rcu(&doi_def->rcu, cipso_v4_doi_free_rcu); 678 } 679 680 /** 681 * cipso_v4_doi_walk - Iterate through the DOI definitions 682 * @skip_cnt: skip past this number of DOI definitions, updated 683 * @callback: callback for each DOI definition 684 * @cb_arg: argument for the callback function 685 * 686 * Description: 687 * Iterate over the DOI definition list, skipping the first @skip_cnt entries. 688 * For each entry call @callback, if @callback returns a negative value stop 689 * 'walking' through the list and return. Updates the value in @skip_cnt upon 690 * return. Returns zero on success, negative values on failure. 691 * 692 */ 693 int cipso_v4_doi_walk(u32 *skip_cnt, 694 int (*callback) (struct cipso_v4_doi *doi_def, void *arg), 695 void *cb_arg) 696 { 697 int ret_val = -ENOENT; 698 u32 doi_cnt = 0; 699 struct cipso_v4_doi *iter_doi; 700 701 rcu_read_lock(); 702 list_for_each_entry_rcu(iter_doi, &cipso_v4_doi_list, list) 703 if (atomic_read(&iter_doi->refcount) > 0) { 704 if (doi_cnt++ < *skip_cnt) 705 continue; 706 ret_val = callback(iter_doi, cb_arg); 707 if (ret_val < 0) { 708 doi_cnt--; 709 goto doi_walk_return; 710 } 711 } 712 713 doi_walk_return: 714 rcu_read_unlock(); 715 *skip_cnt = doi_cnt; 716 return ret_val; 717 } 718 719 /* 720 * Label Mapping Functions 721 */ 722 723 /** 724 * cipso_v4_map_lvl_valid - Checks to see if the given level is understood 725 * @doi_def: the DOI definition 726 * @level: the level to check 727 * 728 * Description: 729 * Checks the given level against the given DOI definition and returns a 730 * negative value if the level does not have a valid mapping and a zero value 731 * if the level is defined by the DOI. 732 * 733 */ 734 static int cipso_v4_map_lvl_valid(const struct cipso_v4_doi *doi_def, u8 level) 735 { 736 switch (doi_def->type) { 737 case CIPSO_V4_MAP_PASS: 738 return 0; 739 case CIPSO_V4_MAP_TRANS: 740 if (doi_def->map.std->lvl.cipso[level] < CIPSO_V4_INV_LVL) 741 return 0; 742 break; 743 } 744 745 return -EFAULT; 746 } 747 748 /** 749 * cipso_v4_map_lvl_hton - Perform a level mapping from the host to the network 750 * @doi_def: the DOI definition 751 * @host_lvl: the host MLS level 752 * @net_lvl: the network/CIPSO MLS level 753 * 754 * Description: 755 * Perform a label mapping to translate a local MLS level to the correct 756 * CIPSO level using the given DOI definition. Returns zero on success, 757 * negative values otherwise. 758 * 759 */ 760 static int cipso_v4_map_lvl_hton(const struct cipso_v4_doi *doi_def, 761 u32 host_lvl, 762 u32 *net_lvl) 763 { 764 switch (doi_def->type) { 765 case CIPSO_V4_MAP_PASS: 766 *net_lvl = host_lvl; 767 return 0; 768 case CIPSO_V4_MAP_TRANS: 769 if (host_lvl < doi_def->map.std->lvl.local_size && 770 doi_def->map.std->lvl.local[host_lvl] < CIPSO_V4_INV_LVL) { 771 *net_lvl = doi_def->map.std->lvl.local[host_lvl]; 772 return 0; 773 } 774 return -EPERM; 775 } 776 777 return -EINVAL; 778 } 779 780 /** 781 * cipso_v4_map_lvl_ntoh - Perform a level mapping from the network to the host 782 * @doi_def: the DOI definition 783 * @net_lvl: the network/CIPSO MLS level 784 * @host_lvl: the host MLS level 785 * 786 * Description: 787 * Perform a label mapping to translate a CIPSO level to the correct local MLS 788 * level using the given DOI definition. Returns zero on success, negative 789 * values otherwise. 790 * 791 */ 792 static int cipso_v4_map_lvl_ntoh(const struct cipso_v4_doi *doi_def, 793 u32 net_lvl, 794 u32 *host_lvl) 795 { 796 struct cipso_v4_std_map_tbl *map_tbl; 797 798 switch (doi_def->type) { 799 case CIPSO_V4_MAP_PASS: 800 *host_lvl = net_lvl; 801 return 0; 802 case CIPSO_V4_MAP_TRANS: 803 map_tbl = doi_def->map.std; 804 if (net_lvl < map_tbl->lvl.cipso_size && 805 map_tbl->lvl.cipso[net_lvl] < CIPSO_V4_INV_LVL) { 806 *host_lvl = doi_def->map.std->lvl.cipso[net_lvl]; 807 return 0; 808 } 809 return -EPERM; 810 } 811 812 return -EINVAL; 813 } 814 815 /** 816 * cipso_v4_map_cat_rbm_valid - Checks to see if the category bitmap is valid 817 * @doi_def: the DOI definition 818 * @bitmap: category bitmap 819 * @bitmap_len: bitmap length in bytes 820 * 821 * Description: 822 * Checks the given category bitmap against the given DOI definition and 823 * returns a negative value if any of the categories in the bitmap do not have 824 * a valid mapping and a zero value if all of the categories are valid. 825 * 826 */ 827 static int cipso_v4_map_cat_rbm_valid(const struct cipso_v4_doi *doi_def, 828 const unsigned char *bitmap, 829 u32 bitmap_len) 830 { 831 int cat = -1; 832 u32 bitmap_len_bits = bitmap_len * 8; 833 u32 cipso_cat_size; 834 u32 *cipso_array; 835 836 switch (doi_def->type) { 837 case CIPSO_V4_MAP_PASS: 838 return 0; 839 case CIPSO_V4_MAP_TRANS: 840 cipso_cat_size = doi_def->map.std->cat.cipso_size; 841 cipso_array = doi_def->map.std->cat.cipso; 842 for (;;) { 843 cat = cipso_v4_bitmap_walk(bitmap, 844 bitmap_len_bits, 845 cat + 1, 846 1); 847 if (cat < 0) 848 break; 849 if (cat >= cipso_cat_size || 850 cipso_array[cat] >= CIPSO_V4_INV_CAT) 851 return -EFAULT; 852 } 853 854 if (cat == -1) 855 return 0; 856 break; 857 } 858 859 return -EFAULT; 860 } 861 862 /** 863 * cipso_v4_map_cat_rbm_hton - Perform a category mapping from host to network 864 * @doi_def: the DOI definition 865 * @secattr: the security attributes 866 * @net_cat: the zero'd out category bitmap in network/CIPSO format 867 * @net_cat_len: the length of the CIPSO bitmap in bytes 868 * 869 * Description: 870 * Perform a label mapping to translate a local MLS category bitmap to the 871 * correct CIPSO bitmap using the given DOI definition. Returns the minimum 872 * size in bytes of the network bitmap on success, negative values otherwise. 873 * 874 */ 875 static int cipso_v4_map_cat_rbm_hton(const struct cipso_v4_doi *doi_def, 876 const struct netlbl_lsm_secattr *secattr, 877 unsigned char *net_cat, 878 u32 net_cat_len) 879 { 880 int host_spot = -1; 881 u32 net_spot = CIPSO_V4_INV_CAT; 882 u32 net_spot_max = 0; 883 u32 net_clen_bits = net_cat_len * 8; 884 u32 host_cat_size = 0; 885 u32 *host_cat_array = NULL; 886 887 if (doi_def->type == CIPSO_V4_MAP_TRANS) { 888 host_cat_size = doi_def->map.std->cat.local_size; 889 host_cat_array = doi_def->map.std->cat.local; 890 } 891 892 for (;;) { 893 host_spot = netlbl_catmap_walk(secattr->attr.mls.cat, 894 host_spot + 1); 895 if (host_spot < 0) 896 break; 897 898 switch (doi_def->type) { 899 case CIPSO_V4_MAP_PASS: 900 net_spot = host_spot; 901 break; 902 case CIPSO_V4_MAP_TRANS: 903 if (host_spot >= host_cat_size) 904 return -EPERM; 905 net_spot = host_cat_array[host_spot]; 906 if (net_spot >= CIPSO_V4_INV_CAT) 907 return -EPERM; 908 break; 909 } 910 if (net_spot >= net_clen_bits) 911 return -ENOSPC; 912 cipso_v4_bitmap_setbit(net_cat, net_spot, 1); 913 914 if (net_spot > net_spot_max) 915 net_spot_max = net_spot; 916 } 917 918 if (++net_spot_max % 8) 919 return net_spot_max / 8 + 1; 920 return net_spot_max / 8; 921 } 922 923 /** 924 * cipso_v4_map_cat_rbm_ntoh - Perform a category mapping from network to host 925 * @doi_def: the DOI definition 926 * @net_cat: the category bitmap in network/CIPSO format 927 * @net_cat_len: the length of the CIPSO bitmap in bytes 928 * @secattr: the security attributes 929 * 930 * Description: 931 * Perform a label mapping to translate a CIPSO bitmap to the correct local 932 * MLS category bitmap using the given DOI definition. Returns zero on 933 * success, negative values on failure. 934 * 935 */ 936 static int cipso_v4_map_cat_rbm_ntoh(const struct cipso_v4_doi *doi_def, 937 const unsigned char *net_cat, 938 u32 net_cat_len, 939 struct netlbl_lsm_secattr *secattr) 940 { 941 int ret_val; 942 int net_spot = -1; 943 u32 host_spot = CIPSO_V4_INV_CAT; 944 u32 net_clen_bits = net_cat_len * 8; 945 u32 net_cat_size = 0; 946 u32 *net_cat_array = NULL; 947 948 if (doi_def->type == CIPSO_V4_MAP_TRANS) { 949 net_cat_size = doi_def->map.std->cat.cipso_size; 950 net_cat_array = doi_def->map.std->cat.cipso; 951 } 952 953 for (;;) { 954 net_spot = cipso_v4_bitmap_walk(net_cat, 955 net_clen_bits, 956 net_spot + 1, 957 1); 958 if (net_spot < 0) { 959 if (net_spot == -2) 960 return -EFAULT; 961 return 0; 962 } 963 964 switch (doi_def->type) { 965 case CIPSO_V4_MAP_PASS: 966 host_spot = net_spot; 967 break; 968 case CIPSO_V4_MAP_TRANS: 969 if (net_spot >= net_cat_size) 970 return -EPERM; 971 host_spot = net_cat_array[net_spot]; 972 if (host_spot >= CIPSO_V4_INV_CAT) 973 return -EPERM; 974 break; 975 } 976 ret_val = netlbl_catmap_setbit(&secattr->attr.mls.cat, 977 host_spot, 978 GFP_ATOMIC); 979 if (ret_val != 0) 980 return ret_val; 981 } 982 983 return -EINVAL; 984 } 985 986 /** 987 * cipso_v4_map_cat_enum_valid - Checks to see if the categories are valid 988 * @doi_def: the DOI definition 989 * @enumcat: category list 990 * @enumcat_len: length of the category list in bytes 991 * 992 * Description: 993 * Checks the given categories against the given DOI definition and returns a 994 * negative value if any of the categories do not have a valid mapping and a 995 * zero value if all of the categories are valid. 996 * 997 */ 998 static int cipso_v4_map_cat_enum_valid(const struct cipso_v4_doi *doi_def, 999 const unsigned char *enumcat, 1000 u32 enumcat_len) 1001 { 1002 u16 cat; 1003 int cat_prev = -1; 1004 u32 iter; 1005 1006 if (doi_def->type != CIPSO_V4_MAP_PASS || enumcat_len & 0x01) 1007 return -EFAULT; 1008 1009 for (iter = 0; iter < enumcat_len; iter += 2) { 1010 cat = get_unaligned_be16(&enumcat[iter]); 1011 if (cat <= cat_prev) 1012 return -EFAULT; 1013 cat_prev = cat; 1014 } 1015 1016 return 0; 1017 } 1018 1019 /** 1020 * cipso_v4_map_cat_enum_hton - Perform a category mapping from host to network 1021 * @doi_def: the DOI definition 1022 * @secattr: the security attributes 1023 * @net_cat: the zero'd out category list in network/CIPSO format 1024 * @net_cat_len: the length of the CIPSO category list in bytes 1025 * 1026 * Description: 1027 * Perform a label mapping to translate a local MLS category bitmap to the 1028 * correct CIPSO category list using the given DOI definition. Returns the 1029 * size in bytes of the network category bitmap on success, negative values 1030 * otherwise. 1031 * 1032 */ 1033 static int cipso_v4_map_cat_enum_hton(const struct cipso_v4_doi *doi_def, 1034 const struct netlbl_lsm_secattr *secattr, 1035 unsigned char *net_cat, 1036 u32 net_cat_len) 1037 { 1038 int cat = -1; 1039 u32 cat_iter = 0; 1040 1041 for (;;) { 1042 cat = netlbl_catmap_walk(secattr->attr.mls.cat, cat + 1); 1043 if (cat < 0) 1044 break; 1045 if ((cat_iter + 2) > net_cat_len) 1046 return -ENOSPC; 1047 1048 *((__be16 *)&net_cat[cat_iter]) = htons(cat); 1049 cat_iter += 2; 1050 } 1051 1052 return cat_iter; 1053 } 1054 1055 /** 1056 * cipso_v4_map_cat_enum_ntoh - Perform a category mapping from network to host 1057 * @doi_def: the DOI definition 1058 * @net_cat: the category list in network/CIPSO format 1059 * @net_cat_len: the length of the CIPSO bitmap in bytes 1060 * @secattr: the security attributes 1061 * 1062 * Description: 1063 * Perform a label mapping to translate a CIPSO category list to the correct 1064 * local MLS category bitmap using the given DOI definition. Returns zero on 1065 * success, negative values on failure. 1066 * 1067 */ 1068 static int cipso_v4_map_cat_enum_ntoh(const struct cipso_v4_doi *doi_def, 1069 const unsigned char *net_cat, 1070 u32 net_cat_len, 1071 struct netlbl_lsm_secattr *secattr) 1072 { 1073 int ret_val; 1074 u32 iter; 1075 1076 for (iter = 0; iter < net_cat_len; iter += 2) { 1077 ret_val = netlbl_catmap_setbit(&secattr->attr.mls.cat, 1078 get_unaligned_be16(&net_cat[iter]), 1079 GFP_ATOMIC); 1080 if (ret_val != 0) 1081 return ret_val; 1082 } 1083 1084 return 0; 1085 } 1086 1087 /** 1088 * cipso_v4_map_cat_rng_valid - Checks to see if the categories are valid 1089 * @doi_def: the DOI definition 1090 * @rngcat: category list 1091 * @rngcat_len: length of the category list in bytes 1092 * 1093 * Description: 1094 * Checks the given categories against the given DOI definition and returns a 1095 * negative value if any of the categories do not have a valid mapping and a 1096 * zero value if all of the categories are valid. 1097 * 1098 */ 1099 static int cipso_v4_map_cat_rng_valid(const struct cipso_v4_doi *doi_def, 1100 const unsigned char *rngcat, 1101 u32 rngcat_len) 1102 { 1103 u16 cat_high; 1104 u16 cat_low; 1105 u32 cat_prev = CIPSO_V4_MAX_REM_CATS + 1; 1106 u32 iter; 1107 1108 if (doi_def->type != CIPSO_V4_MAP_PASS || rngcat_len & 0x01) 1109 return -EFAULT; 1110 1111 for (iter = 0; iter < rngcat_len; iter += 4) { 1112 cat_high = get_unaligned_be16(&rngcat[iter]); 1113 if ((iter + 4) <= rngcat_len) 1114 cat_low = get_unaligned_be16(&rngcat[iter + 2]); 1115 else 1116 cat_low = 0; 1117 1118 if (cat_high > cat_prev) 1119 return -EFAULT; 1120 1121 cat_prev = cat_low; 1122 } 1123 1124 return 0; 1125 } 1126 1127 /** 1128 * cipso_v4_map_cat_rng_hton - Perform a category mapping from host to network 1129 * @doi_def: the DOI definition 1130 * @secattr: the security attributes 1131 * @net_cat: the zero'd out category list in network/CIPSO format 1132 * @net_cat_len: the length of the CIPSO category list in bytes 1133 * 1134 * Description: 1135 * Perform a label mapping to translate a local MLS category bitmap to the 1136 * correct CIPSO category list using the given DOI definition. Returns the 1137 * size in bytes of the network category bitmap on success, negative values 1138 * otherwise. 1139 * 1140 */ 1141 static int cipso_v4_map_cat_rng_hton(const struct cipso_v4_doi *doi_def, 1142 const struct netlbl_lsm_secattr *secattr, 1143 unsigned char *net_cat, 1144 u32 net_cat_len) 1145 { 1146 int iter = -1; 1147 u16 array[CIPSO_V4_TAG_RNG_CAT_MAX * 2]; 1148 u32 array_cnt = 0; 1149 u32 cat_size = 0; 1150 1151 /* make sure we don't overflow the 'array[]' variable */ 1152 if (net_cat_len > 1153 (CIPSO_V4_OPT_LEN_MAX - CIPSO_V4_HDR_LEN - CIPSO_V4_TAG_RNG_BLEN)) 1154 return -ENOSPC; 1155 1156 for (;;) { 1157 iter = netlbl_catmap_walk(secattr->attr.mls.cat, iter + 1); 1158 if (iter < 0) 1159 break; 1160 cat_size += (iter == 0 ? 0 : sizeof(u16)); 1161 if (cat_size > net_cat_len) 1162 return -ENOSPC; 1163 array[array_cnt++] = iter; 1164 1165 iter = netlbl_catmap_walkrng(secattr->attr.mls.cat, iter); 1166 if (iter < 0) 1167 return -EFAULT; 1168 cat_size += sizeof(u16); 1169 if (cat_size > net_cat_len) 1170 return -ENOSPC; 1171 array[array_cnt++] = iter; 1172 } 1173 1174 for (iter = 0; array_cnt > 0;) { 1175 *((__be16 *)&net_cat[iter]) = htons(array[--array_cnt]); 1176 iter += 2; 1177 array_cnt--; 1178 if (array[array_cnt] != 0) { 1179 *((__be16 *)&net_cat[iter]) = htons(array[array_cnt]); 1180 iter += 2; 1181 } 1182 } 1183 1184 return cat_size; 1185 } 1186 1187 /** 1188 * cipso_v4_map_cat_rng_ntoh - Perform a category mapping from network to host 1189 * @doi_def: the DOI definition 1190 * @net_cat: the category list in network/CIPSO format 1191 * @net_cat_len: the length of the CIPSO bitmap in bytes 1192 * @secattr: the security attributes 1193 * 1194 * Description: 1195 * Perform a label mapping to translate a CIPSO category list to the correct 1196 * local MLS category bitmap using the given DOI definition. Returns zero on 1197 * success, negative values on failure. 1198 * 1199 */ 1200 static int cipso_v4_map_cat_rng_ntoh(const struct cipso_v4_doi *doi_def, 1201 const unsigned char *net_cat, 1202 u32 net_cat_len, 1203 struct netlbl_lsm_secattr *secattr) 1204 { 1205 int ret_val; 1206 u32 net_iter; 1207 u16 cat_low; 1208 u16 cat_high; 1209 1210 for (net_iter = 0; net_iter < net_cat_len; net_iter += 4) { 1211 cat_high = get_unaligned_be16(&net_cat[net_iter]); 1212 if ((net_iter + 4) <= net_cat_len) 1213 cat_low = get_unaligned_be16(&net_cat[net_iter + 2]); 1214 else 1215 cat_low = 0; 1216 1217 ret_val = netlbl_catmap_setrng(&secattr->attr.mls.cat, 1218 cat_low, 1219 cat_high, 1220 GFP_ATOMIC); 1221 if (ret_val != 0) 1222 return ret_val; 1223 } 1224 1225 return 0; 1226 } 1227 1228 /* 1229 * Protocol Handling Functions 1230 */ 1231 1232 /** 1233 * cipso_v4_gentag_hdr - Generate a CIPSO option header 1234 * @doi_def: the DOI definition 1235 * @len: the total tag length in bytes, not including this header 1236 * @buf: the CIPSO option buffer 1237 * 1238 * Description: 1239 * Write a CIPSO header into the beginning of @buffer. 1240 * 1241 */ 1242 static void cipso_v4_gentag_hdr(const struct cipso_v4_doi *doi_def, 1243 unsigned char *buf, 1244 u32 len) 1245 { 1246 buf[0] = IPOPT_CIPSO; 1247 buf[1] = CIPSO_V4_HDR_LEN + len; 1248 *(__be32 *)&buf[2] = htonl(doi_def->doi); 1249 } 1250 1251 /** 1252 * cipso_v4_gentag_rbm - Generate a CIPSO restricted bitmap tag (type #1) 1253 * @doi_def: the DOI definition 1254 * @secattr: the security attributes 1255 * @buffer: the option buffer 1256 * @buffer_len: length of buffer in bytes 1257 * 1258 * Description: 1259 * Generate a CIPSO option using the restricted bitmap tag, tag type #1. The 1260 * actual buffer length may be larger than the indicated size due to 1261 * translation between host and network category bitmaps. Returns the size of 1262 * the tag on success, negative values on failure. 1263 * 1264 */ 1265 static int cipso_v4_gentag_rbm(const struct cipso_v4_doi *doi_def, 1266 const struct netlbl_lsm_secattr *secattr, 1267 unsigned char *buffer, 1268 u32 buffer_len) 1269 { 1270 int ret_val; 1271 u32 tag_len; 1272 u32 level; 1273 1274 if ((secattr->flags & NETLBL_SECATTR_MLS_LVL) == 0) 1275 return -EPERM; 1276 1277 ret_val = cipso_v4_map_lvl_hton(doi_def, 1278 secattr->attr.mls.lvl, 1279 &level); 1280 if (ret_val != 0) 1281 return ret_val; 1282 1283 if (secattr->flags & NETLBL_SECATTR_MLS_CAT) { 1284 ret_val = cipso_v4_map_cat_rbm_hton(doi_def, 1285 secattr, 1286 &buffer[4], 1287 buffer_len - 4); 1288 if (ret_val < 0) 1289 return ret_val; 1290 1291 /* This will send packets using the "optimized" format when 1292 * possible as specified in section 3.4.2.6 of the 1293 * CIPSO draft. */ 1294 if (cipso_v4_rbm_optfmt && ret_val > 0 && ret_val <= 10) 1295 tag_len = 14; 1296 else 1297 tag_len = 4 + ret_val; 1298 } else 1299 tag_len = 4; 1300 1301 buffer[0] = CIPSO_V4_TAG_RBITMAP; 1302 buffer[1] = tag_len; 1303 buffer[3] = level; 1304 1305 return tag_len; 1306 } 1307 1308 /** 1309 * cipso_v4_parsetag_rbm - Parse a CIPSO restricted bitmap tag 1310 * @doi_def: the DOI definition 1311 * @tag: the CIPSO tag 1312 * @secattr: the security attributes 1313 * 1314 * Description: 1315 * Parse a CIPSO restricted bitmap tag (tag type #1) and return the security 1316 * attributes in @secattr. Return zero on success, negatives values on 1317 * failure. 1318 * 1319 */ 1320 static int cipso_v4_parsetag_rbm(const struct cipso_v4_doi *doi_def, 1321 const unsigned char *tag, 1322 struct netlbl_lsm_secattr *secattr) 1323 { 1324 int ret_val; 1325 u8 tag_len = tag[1]; 1326 u32 level; 1327 1328 ret_val = cipso_v4_map_lvl_ntoh(doi_def, tag[3], &level); 1329 if (ret_val != 0) 1330 return ret_val; 1331 secattr->attr.mls.lvl = level; 1332 secattr->flags |= NETLBL_SECATTR_MLS_LVL; 1333 1334 if (tag_len > 4) { 1335 ret_val = cipso_v4_map_cat_rbm_ntoh(doi_def, 1336 &tag[4], 1337 tag_len - 4, 1338 secattr); 1339 if (ret_val != 0) { 1340 netlbl_catmap_free(secattr->attr.mls.cat); 1341 return ret_val; 1342 } 1343 1344 secattr->flags |= NETLBL_SECATTR_MLS_CAT; 1345 } 1346 1347 return 0; 1348 } 1349 1350 /** 1351 * cipso_v4_gentag_enum - Generate a CIPSO enumerated tag (type #2) 1352 * @doi_def: the DOI definition 1353 * @secattr: the security attributes 1354 * @buffer: the option buffer 1355 * @buffer_len: length of buffer in bytes 1356 * 1357 * Description: 1358 * Generate a CIPSO option using the enumerated tag, tag type #2. Returns the 1359 * size of the tag on success, negative values on failure. 1360 * 1361 */ 1362 static int cipso_v4_gentag_enum(const struct cipso_v4_doi *doi_def, 1363 const struct netlbl_lsm_secattr *secattr, 1364 unsigned char *buffer, 1365 u32 buffer_len) 1366 { 1367 int ret_val; 1368 u32 tag_len; 1369 u32 level; 1370 1371 if (!(secattr->flags & NETLBL_SECATTR_MLS_LVL)) 1372 return -EPERM; 1373 1374 ret_val = cipso_v4_map_lvl_hton(doi_def, 1375 secattr->attr.mls.lvl, 1376 &level); 1377 if (ret_val != 0) 1378 return ret_val; 1379 1380 if (secattr->flags & NETLBL_SECATTR_MLS_CAT) { 1381 ret_val = cipso_v4_map_cat_enum_hton(doi_def, 1382 secattr, 1383 &buffer[4], 1384 buffer_len - 4); 1385 if (ret_val < 0) 1386 return ret_val; 1387 1388 tag_len = 4 + ret_val; 1389 } else 1390 tag_len = 4; 1391 1392 buffer[0] = CIPSO_V4_TAG_ENUM; 1393 buffer[1] = tag_len; 1394 buffer[3] = level; 1395 1396 return tag_len; 1397 } 1398 1399 /** 1400 * cipso_v4_parsetag_enum - Parse a CIPSO enumerated tag 1401 * @doi_def: the DOI definition 1402 * @tag: the CIPSO tag 1403 * @secattr: the security attributes 1404 * 1405 * Description: 1406 * Parse a CIPSO enumerated tag (tag type #2) and return the security 1407 * attributes in @secattr. Return zero on success, negatives values on 1408 * failure. 1409 * 1410 */ 1411 static int cipso_v4_parsetag_enum(const struct cipso_v4_doi *doi_def, 1412 const unsigned char *tag, 1413 struct netlbl_lsm_secattr *secattr) 1414 { 1415 int ret_val; 1416 u8 tag_len = tag[1]; 1417 u32 level; 1418 1419 ret_val = cipso_v4_map_lvl_ntoh(doi_def, tag[3], &level); 1420 if (ret_val != 0) 1421 return ret_val; 1422 secattr->attr.mls.lvl = level; 1423 secattr->flags |= NETLBL_SECATTR_MLS_LVL; 1424 1425 if (tag_len > 4) { 1426 ret_val = cipso_v4_map_cat_enum_ntoh(doi_def, 1427 &tag[4], 1428 tag_len - 4, 1429 secattr); 1430 if (ret_val != 0) { 1431 netlbl_catmap_free(secattr->attr.mls.cat); 1432 return ret_val; 1433 } 1434 1435 secattr->flags |= NETLBL_SECATTR_MLS_CAT; 1436 } 1437 1438 return 0; 1439 } 1440 1441 /** 1442 * cipso_v4_gentag_rng - Generate a CIPSO ranged tag (type #5) 1443 * @doi_def: the DOI definition 1444 * @secattr: the security attributes 1445 * @buffer: the option buffer 1446 * @buffer_len: length of buffer in bytes 1447 * 1448 * Description: 1449 * Generate a CIPSO option using the ranged tag, tag type #5. Returns the 1450 * size of the tag on success, negative values on failure. 1451 * 1452 */ 1453 static int cipso_v4_gentag_rng(const struct cipso_v4_doi *doi_def, 1454 const struct netlbl_lsm_secattr *secattr, 1455 unsigned char *buffer, 1456 u32 buffer_len) 1457 { 1458 int ret_val; 1459 u32 tag_len; 1460 u32 level; 1461 1462 if (!(secattr->flags & NETLBL_SECATTR_MLS_LVL)) 1463 return -EPERM; 1464 1465 ret_val = cipso_v4_map_lvl_hton(doi_def, 1466 secattr->attr.mls.lvl, 1467 &level); 1468 if (ret_val != 0) 1469 return ret_val; 1470 1471 if (secattr->flags & NETLBL_SECATTR_MLS_CAT) { 1472 ret_val = cipso_v4_map_cat_rng_hton(doi_def, 1473 secattr, 1474 &buffer[4], 1475 buffer_len - 4); 1476 if (ret_val < 0) 1477 return ret_val; 1478 1479 tag_len = 4 + ret_val; 1480 } else 1481 tag_len = 4; 1482 1483 buffer[0] = CIPSO_V4_TAG_RANGE; 1484 buffer[1] = tag_len; 1485 buffer[3] = level; 1486 1487 return tag_len; 1488 } 1489 1490 /** 1491 * cipso_v4_parsetag_rng - Parse a CIPSO ranged tag 1492 * @doi_def: the DOI definition 1493 * @tag: the CIPSO tag 1494 * @secattr: the security attributes 1495 * 1496 * Description: 1497 * Parse a CIPSO ranged tag (tag type #5) and return the security attributes 1498 * in @secattr. Return zero on success, negatives values on failure. 1499 * 1500 */ 1501 static int cipso_v4_parsetag_rng(const struct cipso_v4_doi *doi_def, 1502 const unsigned char *tag, 1503 struct netlbl_lsm_secattr *secattr) 1504 { 1505 int ret_val; 1506 u8 tag_len = tag[1]; 1507 u32 level; 1508 1509 ret_val = cipso_v4_map_lvl_ntoh(doi_def, tag[3], &level); 1510 if (ret_val != 0) 1511 return ret_val; 1512 secattr->attr.mls.lvl = level; 1513 secattr->flags |= NETLBL_SECATTR_MLS_LVL; 1514 1515 if (tag_len > 4) { 1516 ret_val = cipso_v4_map_cat_rng_ntoh(doi_def, 1517 &tag[4], 1518 tag_len - 4, 1519 secattr); 1520 if (ret_val != 0) { 1521 netlbl_catmap_free(secattr->attr.mls.cat); 1522 return ret_val; 1523 } 1524 1525 secattr->flags |= NETLBL_SECATTR_MLS_CAT; 1526 } 1527 1528 return 0; 1529 } 1530 1531 /** 1532 * cipso_v4_gentag_loc - Generate a CIPSO local tag (non-standard) 1533 * @doi_def: the DOI definition 1534 * @secattr: the security attributes 1535 * @buffer: the option buffer 1536 * @buffer_len: length of buffer in bytes 1537 * 1538 * Description: 1539 * Generate a CIPSO option using the local tag. Returns the size of the tag 1540 * on success, negative values on failure. 1541 * 1542 */ 1543 static int cipso_v4_gentag_loc(const struct cipso_v4_doi *doi_def, 1544 const struct netlbl_lsm_secattr *secattr, 1545 unsigned char *buffer, 1546 u32 buffer_len) 1547 { 1548 if (!(secattr->flags & NETLBL_SECATTR_SECID)) 1549 return -EPERM; 1550 1551 buffer[0] = CIPSO_V4_TAG_LOCAL; 1552 buffer[1] = CIPSO_V4_TAG_LOC_BLEN; 1553 *(u32 *)&buffer[2] = secattr->attr.secid; 1554 1555 return CIPSO_V4_TAG_LOC_BLEN; 1556 } 1557 1558 /** 1559 * cipso_v4_parsetag_loc - Parse a CIPSO local tag 1560 * @doi_def: the DOI definition 1561 * @tag: the CIPSO tag 1562 * @secattr: the security attributes 1563 * 1564 * Description: 1565 * Parse a CIPSO local tag and return the security attributes in @secattr. 1566 * Return zero on success, negatives values on failure. 1567 * 1568 */ 1569 static int cipso_v4_parsetag_loc(const struct cipso_v4_doi *doi_def, 1570 const unsigned char *tag, 1571 struct netlbl_lsm_secattr *secattr) 1572 { 1573 secattr->attr.secid = *(u32 *)&tag[2]; 1574 secattr->flags |= NETLBL_SECATTR_SECID; 1575 1576 return 0; 1577 } 1578 1579 /** 1580 * cipso_v4_optptr - Find the CIPSO option in the packet 1581 * @skb: the packet 1582 * 1583 * Description: 1584 * Parse the packet's IP header looking for a CIPSO option. Returns a pointer 1585 * to the start of the CIPSO option on success, NULL if one if not found. 1586 * 1587 */ 1588 unsigned char *cipso_v4_optptr(const struct sk_buff *skb) 1589 { 1590 const struct iphdr *iph = ip_hdr(skb); 1591 unsigned char *optptr = (unsigned char *)&(ip_hdr(skb)[1]); 1592 int optlen; 1593 int taglen; 1594 1595 for (optlen = iph->ihl*4 - sizeof(struct iphdr); optlen > 0; ) { 1596 if (optptr[0] == IPOPT_CIPSO) 1597 return optptr; 1598 taglen = optptr[1]; 1599 optlen -= taglen; 1600 optptr += taglen; 1601 } 1602 1603 return NULL; 1604 } 1605 1606 /** 1607 * cipso_v4_validate - Validate a CIPSO option 1608 * @option: the start of the option, on error it is set to point to the error 1609 * 1610 * Description: 1611 * This routine is called to validate a CIPSO option, it checks all of the 1612 * fields to ensure that they are at least valid, see the draft snippet below 1613 * for details. If the option is valid then a zero value is returned and 1614 * the value of @option is unchanged. If the option is invalid then a 1615 * non-zero value is returned and @option is adjusted to point to the 1616 * offending portion of the option. From the IETF draft ... 1617 * 1618 * "If any field within the CIPSO options, such as the DOI identifier, is not 1619 * recognized the IP datagram is discarded and an ICMP 'parameter problem' 1620 * (type 12) is generated and returned. The ICMP code field is set to 'bad 1621 * parameter' (code 0) and the pointer is set to the start of the CIPSO field 1622 * that is unrecognized." 1623 * 1624 */ 1625 int cipso_v4_validate(const struct sk_buff *skb, unsigned char **option) 1626 { 1627 unsigned char *opt = *option; 1628 unsigned char *tag; 1629 unsigned char opt_iter; 1630 unsigned char err_offset = 0; 1631 u8 opt_len; 1632 u8 tag_len; 1633 struct cipso_v4_doi *doi_def = NULL; 1634 u32 tag_iter; 1635 1636 /* caller already checks for length values that are too large */ 1637 opt_len = opt[1]; 1638 if (opt_len < 8) { 1639 err_offset = 1; 1640 goto validate_return; 1641 } 1642 1643 rcu_read_lock(); 1644 doi_def = cipso_v4_doi_search(get_unaligned_be32(&opt[2])); 1645 if (!doi_def) { 1646 err_offset = 2; 1647 goto validate_return_locked; 1648 } 1649 1650 opt_iter = CIPSO_V4_HDR_LEN; 1651 tag = opt + opt_iter; 1652 while (opt_iter < opt_len) { 1653 for (tag_iter = 0; doi_def->tags[tag_iter] != tag[0];) 1654 if (doi_def->tags[tag_iter] == CIPSO_V4_TAG_INVALID || 1655 ++tag_iter == CIPSO_V4_TAG_MAXCNT) { 1656 err_offset = opt_iter; 1657 goto validate_return_locked; 1658 } 1659 1660 tag_len = tag[1]; 1661 if (tag_len > (opt_len - opt_iter)) { 1662 err_offset = opt_iter + 1; 1663 goto validate_return_locked; 1664 } 1665 1666 switch (tag[0]) { 1667 case CIPSO_V4_TAG_RBITMAP: 1668 if (tag_len < CIPSO_V4_TAG_RBM_BLEN) { 1669 err_offset = opt_iter + 1; 1670 goto validate_return_locked; 1671 } 1672 1673 /* We are already going to do all the verification 1674 * necessary at the socket layer so from our point of 1675 * view it is safe to turn these checks off (and less 1676 * work), however, the CIPSO draft says we should do 1677 * all the CIPSO validations here but it doesn't 1678 * really specify _exactly_ what we need to validate 1679 * ... so, just make it a sysctl tunable. */ 1680 if (cipso_v4_rbm_strictvalid) { 1681 if (cipso_v4_map_lvl_valid(doi_def, 1682 tag[3]) < 0) { 1683 err_offset = opt_iter + 3; 1684 goto validate_return_locked; 1685 } 1686 if (tag_len > CIPSO_V4_TAG_RBM_BLEN && 1687 cipso_v4_map_cat_rbm_valid(doi_def, 1688 &tag[4], 1689 tag_len - 4) < 0) { 1690 err_offset = opt_iter + 4; 1691 goto validate_return_locked; 1692 } 1693 } 1694 break; 1695 case CIPSO_V4_TAG_ENUM: 1696 if (tag_len < CIPSO_V4_TAG_ENUM_BLEN) { 1697 err_offset = opt_iter + 1; 1698 goto validate_return_locked; 1699 } 1700 1701 if (cipso_v4_map_lvl_valid(doi_def, 1702 tag[3]) < 0) { 1703 err_offset = opt_iter + 3; 1704 goto validate_return_locked; 1705 } 1706 if (tag_len > CIPSO_V4_TAG_ENUM_BLEN && 1707 cipso_v4_map_cat_enum_valid(doi_def, 1708 &tag[4], 1709 tag_len - 4) < 0) { 1710 err_offset = opt_iter + 4; 1711 goto validate_return_locked; 1712 } 1713 break; 1714 case CIPSO_V4_TAG_RANGE: 1715 if (tag_len < CIPSO_V4_TAG_RNG_BLEN) { 1716 err_offset = opt_iter + 1; 1717 goto validate_return_locked; 1718 } 1719 1720 if (cipso_v4_map_lvl_valid(doi_def, 1721 tag[3]) < 0) { 1722 err_offset = opt_iter + 3; 1723 goto validate_return_locked; 1724 } 1725 if (tag_len > CIPSO_V4_TAG_RNG_BLEN && 1726 cipso_v4_map_cat_rng_valid(doi_def, 1727 &tag[4], 1728 tag_len - 4) < 0) { 1729 err_offset = opt_iter + 4; 1730 goto validate_return_locked; 1731 } 1732 break; 1733 case CIPSO_V4_TAG_LOCAL: 1734 /* This is a non-standard tag that we only allow for 1735 * local connections, so if the incoming interface is 1736 * not the loopback device drop the packet. Further, 1737 * there is no legitimate reason for setting this from 1738 * userspace so reject it if skb is NULL. */ 1739 if (!skb || !(skb->dev->flags & IFF_LOOPBACK)) { 1740 err_offset = opt_iter; 1741 goto validate_return_locked; 1742 } 1743 if (tag_len != CIPSO_V4_TAG_LOC_BLEN) { 1744 err_offset = opt_iter + 1; 1745 goto validate_return_locked; 1746 } 1747 break; 1748 default: 1749 err_offset = opt_iter; 1750 goto validate_return_locked; 1751 } 1752 1753 tag += tag_len; 1754 opt_iter += tag_len; 1755 } 1756 1757 validate_return_locked: 1758 rcu_read_unlock(); 1759 validate_return: 1760 *option = opt + err_offset; 1761 return err_offset; 1762 } 1763 1764 /** 1765 * cipso_v4_error - Send the correct response for a bad packet 1766 * @skb: the packet 1767 * @error: the error code 1768 * @gateway: CIPSO gateway flag 1769 * 1770 * Description: 1771 * Based on the error code given in @error, send an ICMP error message back to 1772 * the originating host. From the IETF draft ... 1773 * 1774 * "If the contents of the CIPSO [option] are valid but the security label is 1775 * outside of the configured host or port label range, the datagram is 1776 * discarded and an ICMP 'destination unreachable' (type 3) is generated and 1777 * returned. The code field of the ICMP is set to 'communication with 1778 * destination network administratively prohibited' (code 9) or to 1779 * 'communication with destination host administratively prohibited' 1780 * (code 10). The value of the code is dependent on whether the originator 1781 * of the ICMP message is acting as a CIPSO host or a CIPSO gateway. The 1782 * recipient of the ICMP message MUST be able to handle either value. The 1783 * same procedure is performed if a CIPSO [option] can not be added to an 1784 * IP packet because it is too large to fit in the IP options area." 1785 * 1786 * "If the error is triggered by receipt of an ICMP message, the message is 1787 * discarded and no response is permitted (consistent with general ICMP 1788 * processing rules)." 1789 * 1790 */ 1791 void cipso_v4_error(struct sk_buff *skb, int error, u32 gateway) 1792 { 1793 if (ip_hdr(skb)->protocol == IPPROTO_ICMP || error != -EACCES) 1794 return; 1795 1796 if (gateway) 1797 icmp_send(skb, ICMP_DEST_UNREACH, ICMP_NET_ANO, 0); 1798 else 1799 icmp_send(skb, ICMP_DEST_UNREACH, ICMP_HOST_ANO, 0); 1800 } 1801 1802 /** 1803 * cipso_v4_genopt - Generate a CIPSO option 1804 * @buf: the option buffer 1805 * @buf_len: the size of opt_buf 1806 * @doi_def: the CIPSO DOI to use 1807 * @secattr: the security attributes 1808 * 1809 * Description: 1810 * Generate a CIPSO option using the DOI definition and security attributes 1811 * passed to the function. Returns the length of the option on success and 1812 * negative values on failure. 1813 * 1814 */ 1815 static int cipso_v4_genopt(unsigned char *buf, u32 buf_len, 1816 const struct cipso_v4_doi *doi_def, 1817 const struct netlbl_lsm_secattr *secattr) 1818 { 1819 int ret_val; 1820 u32 iter; 1821 1822 if (buf_len <= CIPSO_V4_HDR_LEN) 1823 return -ENOSPC; 1824 1825 /* XXX - This code assumes only one tag per CIPSO option which isn't 1826 * really a good assumption to make but since we only support the MAC 1827 * tags right now it is a safe assumption. */ 1828 iter = 0; 1829 do { 1830 memset(buf, 0, buf_len); 1831 switch (doi_def->tags[iter]) { 1832 case CIPSO_V4_TAG_RBITMAP: 1833 ret_val = cipso_v4_gentag_rbm(doi_def, 1834 secattr, 1835 &buf[CIPSO_V4_HDR_LEN], 1836 buf_len - CIPSO_V4_HDR_LEN); 1837 break; 1838 case CIPSO_V4_TAG_ENUM: 1839 ret_val = cipso_v4_gentag_enum(doi_def, 1840 secattr, 1841 &buf[CIPSO_V4_HDR_LEN], 1842 buf_len - CIPSO_V4_HDR_LEN); 1843 break; 1844 case CIPSO_V4_TAG_RANGE: 1845 ret_val = cipso_v4_gentag_rng(doi_def, 1846 secattr, 1847 &buf[CIPSO_V4_HDR_LEN], 1848 buf_len - CIPSO_V4_HDR_LEN); 1849 break; 1850 case CIPSO_V4_TAG_LOCAL: 1851 ret_val = cipso_v4_gentag_loc(doi_def, 1852 secattr, 1853 &buf[CIPSO_V4_HDR_LEN], 1854 buf_len - CIPSO_V4_HDR_LEN); 1855 break; 1856 default: 1857 return -EPERM; 1858 } 1859 1860 iter++; 1861 } while (ret_val < 0 && 1862 iter < CIPSO_V4_TAG_MAXCNT && 1863 doi_def->tags[iter] != CIPSO_V4_TAG_INVALID); 1864 if (ret_val < 0) 1865 return ret_val; 1866 cipso_v4_gentag_hdr(doi_def, buf, ret_val); 1867 return CIPSO_V4_HDR_LEN + ret_val; 1868 } 1869 1870 /** 1871 * cipso_v4_sock_setattr - Add a CIPSO option to a socket 1872 * @sk: the socket 1873 * @doi_def: the CIPSO DOI to use 1874 * @secattr: the specific security attributes of the socket 1875 * 1876 * Description: 1877 * Set the CIPSO option on the given socket using the DOI definition and 1878 * security attributes passed to the function. This function requires 1879 * exclusive access to @sk, which means it either needs to be in the 1880 * process of being created or locked. Returns zero on success and negative 1881 * values on failure. 1882 * 1883 */ 1884 int cipso_v4_sock_setattr(struct sock *sk, 1885 const struct cipso_v4_doi *doi_def, 1886 const struct netlbl_lsm_secattr *secattr) 1887 { 1888 int ret_val = -EPERM; 1889 unsigned char *buf = NULL; 1890 u32 buf_len; 1891 u32 opt_len; 1892 struct ip_options_rcu *old, *opt = NULL; 1893 struct inet_sock *sk_inet; 1894 struct inet_connection_sock *sk_conn; 1895 1896 /* In the case of sock_create_lite(), the sock->sk field is not 1897 * defined yet but it is not a problem as the only users of these 1898 * "lite" PF_INET sockets are functions which do an accept() call 1899 * afterwards so we will label the socket as part of the accept(). */ 1900 if (!sk) 1901 return 0; 1902 1903 /* We allocate the maximum CIPSO option size here so we are probably 1904 * being a little wasteful, but it makes our life _much_ easier later 1905 * on and after all we are only talking about 40 bytes. */ 1906 buf_len = CIPSO_V4_OPT_LEN_MAX; 1907 buf = kmalloc(buf_len, GFP_ATOMIC); 1908 if (!buf) { 1909 ret_val = -ENOMEM; 1910 goto socket_setattr_failure; 1911 } 1912 1913 ret_val = cipso_v4_genopt(buf, buf_len, doi_def, secattr); 1914 if (ret_val < 0) 1915 goto socket_setattr_failure; 1916 buf_len = ret_val; 1917 1918 /* We can't use ip_options_get() directly because it makes a call to 1919 * ip_options_get_alloc() which allocates memory with GFP_KERNEL and 1920 * we won't always have CAP_NET_RAW even though we _always_ want to 1921 * set the IPOPT_CIPSO option. */ 1922 opt_len = (buf_len + 3) & ~3; 1923 opt = kzalloc(sizeof(*opt) + opt_len, GFP_ATOMIC); 1924 if (!opt) { 1925 ret_val = -ENOMEM; 1926 goto socket_setattr_failure; 1927 } 1928 memcpy(opt->opt.__data, buf, buf_len); 1929 opt->opt.optlen = opt_len; 1930 opt->opt.cipso = sizeof(struct iphdr); 1931 kfree(buf); 1932 buf = NULL; 1933 1934 sk_inet = inet_sk(sk); 1935 1936 old = rcu_dereference_protected(sk_inet->inet_opt, sock_owned_by_user(sk)); 1937 if (sk_inet->is_icsk) { 1938 sk_conn = inet_csk(sk); 1939 if (old) 1940 sk_conn->icsk_ext_hdr_len -= old->opt.optlen; 1941 sk_conn->icsk_ext_hdr_len += opt->opt.optlen; 1942 sk_conn->icsk_sync_mss(sk, sk_conn->icsk_pmtu_cookie); 1943 } 1944 rcu_assign_pointer(sk_inet->inet_opt, opt); 1945 if (old) 1946 kfree_rcu(old, rcu); 1947 1948 return 0; 1949 1950 socket_setattr_failure: 1951 kfree(buf); 1952 kfree(opt); 1953 return ret_val; 1954 } 1955 1956 /** 1957 * cipso_v4_req_setattr - Add a CIPSO option to a connection request socket 1958 * @req: the connection request socket 1959 * @doi_def: the CIPSO DOI to use 1960 * @secattr: the specific security attributes of the socket 1961 * 1962 * Description: 1963 * Set the CIPSO option on the given socket using the DOI definition and 1964 * security attributes passed to the function. Returns zero on success and 1965 * negative values on failure. 1966 * 1967 */ 1968 int cipso_v4_req_setattr(struct request_sock *req, 1969 const struct cipso_v4_doi *doi_def, 1970 const struct netlbl_lsm_secattr *secattr) 1971 { 1972 int ret_val = -EPERM; 1973 unsigned char *buf = NULL; 1974 u32 buf_len; 1975 u32 opt_len; 1976 struct ip_options_rcu *opt = NULL; 1977 struct inet_request_sock *req_inet; 1978 1979 /* We allocate the maximum CIPSO option size here so we are probably 1980 * being a little wasteful, but it makes our life _much_ easier later 1981 * on and after all we are only talking about 40 bytes. */ 1982 buf_len = CIPSO_V4_OPT_LEN_MAX; 1983 buf = kmalloc(buf_len, GFP_ATOMIC); 1984 if (!buf) { 1985 ret_val = -ENOMEM; 1986 goto req_setattr_failure; 1987 } 1988 1989 ret_val = cipso_v4_genopt(buf, buf_len, doi_def, secattr); 1990 if (ret_val < 0) 1991 goto req_setattr_failure; 1992 buf_len = ret_val; 1993 1994 /* We can't use ip_options_get() directly because it makes a call to 1995 * ip_options_get_alloc() which allocates memory with GFP_KERNEL and 1996 * we won't always have CAP_NET_RAW even though we _always_ want to 1997 * set the IPOPT_CIPSO option. */ 1998 opt_len = (buf_len + 3) & ~3; 1999 opt = kzalloc(sizeof(*opt) + opt_len, GFP_ATOMIC); 2000 if (!opt) { 2001 ret_val = -ENOMEM; 2002 goto req_setattr_failure; 2003 } 2004 memcpy(opt->opt.__data, buf, buf_len); 2005 opt->opt.optlen = opt_len; 2006 opt->opt.cipso = sizeof(struct iphdr); 2007 kfree(buf); 2008 buf = NULL; 2009 2010 req_inet = inet_rsk(req); 2011 opt = xchg(&req_inet->opt, opt); 2012 if (opt) 2013 kfree_rcu(opt, rcu); 2014 2015 return 0; 2016 2017 req_setattr_failure: 2018 kfree(buf); 2019 kfree(opt); 2020 return ret_val; 2021 } 2022 2023 /** 2024 * cipso_v4_delopt - Delete the CIPSO option from a set of IP options 2025 * @opt_ptr: IP option pointer 2026 * 2027 * Description: 2028 * Deletes the CIPSO IP option from a set of IP options and makes the necessary 2029 * adjustments to the IP option structure. Returns zero on success, negative 2030 * values on failure. 2031 * 2032 */ 2033 static int cipso_v4_delopt(struct ip_options_rcu **opt_ptr) 2034 { 2035 int hdr_delta = 0; 2036 struct ip_options_rcu *opt = *opt_ptr; 2037 2038 if (opt->opt.srr || opt->opt.rr || opt->opt.ts || opt->opt.router_alert) { 2039 u8 cipso_len; 2040 u8 cipso_off; 2041 unsigned char *cipso_ptr; 2042 int iter; 2043 int optlen_new; 2044 2045 cipso_off = opt->opt.cipso - sizeof(struct iphdr); 2046 cipso_ptr = &opt->opt.__data[cipso_off]; 2047 cipso_len = cipso_ptr[1]; 2048 2049 if (opt->opt.srr > opt->opt.cipso) 2050 opt->opt.srr -= cipso_len; 2051 if (opt->opt.rr > opt->opt.cipso) 2052 opt->opt.rr -= cipso_len; 2053 if (opt->opt.ts > opt->opt.cipso) 2054 opt->opt.ts -= cipso_len; 2055 if (opt->opt.router_alert > opt->opt.cipso) 2056 opt->opt.router_alert -= cipso_len; 2057 opt->opt.cipso = 0; 2058 2059 memmove(cipso_ptr, cipso_ptr + cipso_len, 2060 opt->opt.optlen - cipso_off - cipso_len); 2061 2062 /* determining the new total option length is tricky because of 2063 * the padding necessary, the only thing i can think to do at 2064 * this point is walk the options one-by-one, skipping the 2065 * padding at the end to determine the actual option size and 2066 * from there we can determine the new total option length */ 2067 iter = 0; 2068 optlen_new = 0; 2069 while (iter < opt->opt.optlen) 2070 if (opt->opt.__data[iter] != IPOPT_NOP) { 2071 iter += opt->opt.__data[iter + 1]; 2072 optlen_new = iter; 2073 } else 2074 iter++; 2075 hdr_delta = opt->opt.optlen; 2076 opt->opt.optlen = (optlen_new + 3) & ~3; 2077 hdr_delta -= opt->opt.optlen; 2078 } else { 2079 /* only the cipso option was present on the socket so we can 2080 * remove the entire option struct */ 2081 *opt_ptr = NULL; 2082 hdr_delta = opt->opt.optlen; 2083 kfree_rcu(opt, rcu); 2084 } 2085 2086 return hdr_delta; 2087 } 2088 2089 /** 2090 * cipso_v4_sock_delattr - Delete the CIPSO option from a socket 2091 * @sk: the socket 2092 * 2093 * Description: 2094 * Removes the CIPSO option from a socket, if present. 2095 * 2096 */ 2097 void cipso_v4_sock_delattr(struct sock *sk) 2098 { 2099 int hdr_delta; 2100 struct ip_options_rcu *opt; 2101 struct inet_sock *sk_inet; 2102 2103 sk_inet = inet_sk(sk); 2104 opt = rcu_dereference_protected(sk_inet->inet_opt, 1); 2105 if (!opt || opt->opt.cipso == 0) 2106 return; 2107 2108 hdr_delta = cipso_v4_delopt(&sk_inet->inet_opt); 2109 if (sk_inet->is_icsk && hdr_delta > 0) { 2110 struct inet_connection_sock *sk_conn = inet_csk(sk); 2111 sk_conn->icsk_ext_hdr_len -= hdr_delta; 2112 sk_conn->icsk_sync_mss(sk, sk_conn->icsk_pmtu_cookie); 2113 } 2114 } 2115 2116 /** 2117 * cipso_v4_req_delattr - Delete the CIPSO option from a request socket 2118 * @reg: the request socket 2119 * 2120 * Description: 2121 * Removes the CIPSO option from a request socket, if present. 2122 * 2123 */ 2124 void cipso_v4_req_delattr(struct request_sock *req) 2125 { 2126 struct ip_options_rcu *opt; 2127 struct inet_request_sock *req_inet; 2128 2129 req_inet = inet_rsk(req); 2130 opt = req_inet->opt; 2131 if (!opt || opt->opt.cipso == 0) 2132 return; 2133 2134 cipso_v4_delopt(&req_inet->opt); 2135 } 2136 2137 /** 2138 * cipso_v4_getattr - Helper function for the cipso_v4_*_getattr functions 2139 * @cipso: the CIPSO v4 option 2140 * @secattr: the security attributes 2141 * 2142 * Description: 2143 * Inspect @cipso and return the security attributes in @secattr. Returns zero 2144 * on success and negative values on failure. 2145 * 2146 */ 2147 int cipso_v4_getattr(const unsigned char *cipso, 2148 struct netlbl_lsm_secattr *secattr) 2149 { 2150 int ret_val = -ENOMSG; 2151 u32 doi; 2152 struct cipso_v4_doi *doi_def; 2153 2154 if (cipso_v4_cache_check(cipso, cipso[1], secattr) == 0) 2155 return 0; 2156 2157 doi = get_unaligned_be32(&cipso[2]); 2158 rcu_read_lock(); 2159 doi_def = cipso_v4_doi_search(doi); 2160 if (!doi_def) 2161 goto getattr_return; 2162 /* XXX - This code assumes only one tag per CIPSO option which isn't 2163 * really a good assumption to make but since we only support the MAC 2164 * tags right now it is a safe assumption. */ 2165 switch (cipso[6]) { 2166 case CIPSO_V4_TAG_RBITMAP: 2167 ret_val = cipso_v4_parsetag_rbm(doi_def, &cipso[6], secattr); 2168 break; 2169 case CIPSO_V4_TAG_ENUM: 2170 ret_val = cipso_v4_parsetag_enum(doi_def, &cipso[6], secattr); 2171 break; 2172 case CIPSO_V4_TAG_RANGE: 2173 ret_val = cipso_v4_parsetag_rng(doi_def, &cipso[6], secattr); 2174 break; 2175 case CIPSO_V4_TAG_LOCAL: 2176 ret_val = cipso_v4_parsetag_loc(doi_def, &cipso[6], secattr); 2177 break; 2178 } 2179 if (ret_val == 0) 2180 secattr->type = NETLBL_NLTYPE_CIPSOV4; 2181 2182 getattr_return: 2183 rcu_read_unlock(); 2184 return ret_val; 2185 } 2186 2187 /** 2188 * cipso_v4_sock_getattr - Get the security attributes from a sock 2189 * @sk: the sock 2190 * @secattr: the security attributes 2191 * 2192 * Description: 2193 * Query @sk to see if there is a CIPSO option attached to the sock and if 2194 * there is return the CIPSO security attributes in @secattr. This function 2195 * requires that @sk be locked, or privately held, but it does not do any 2196 * locking itself. Returns zero on success and negative values on failure. 2197 * 2198 */ 2199 int cipso_v4_sock_getattr(struct sock *sk, struct netlbl_lsm_secattr *secattr) 2200 { 2201 struct ip_options_rcu *opt; 2202 int res = -ENOMSG; 2203 2204 rcu_read_lock(); 2205 opt = rcu_dereference(inet_sk(sk)->inet_opt); 2206 if (opt && opt->opt.cipso) 2207 res = cipso_v4_getattr(opt->opt.__data + 2208 opt->opt.cipso - 2209 sizeof(struct iphdr), 2210 secattr); 2211 rcu_read_unlock(); 2212 return res; 2213 } 2214 2215 /** 2216 * cipso_v4_skbuff_setattr - Set the CIPSO option on a packet 2217 * @skb: the packet 2218 * @secattr: the security attributes 2219 * 2220 * Description: 2221 * Set the CIPSO option on the given packet based on the security attributes. 2222 * Returns a pointer to the IP header on success and NULL on failure. 2223 * 2224 */ 2225 int cipso_v4_skbuff_setattr(struct sk_buff *skb, 2226 const struct cipso_v4_doi *doi_def, 2227 const struct netlbl_lsm_secattr *secattr) 2228 { 2229 int ret_val; 2230 struct iphdr *iph; 2231 struct ip_options *opt = &IPCB(skb)->opt; 2232 unsigned char buf[CIPSO_V4_OPT_LEN_MAX]; 2233 u32 buf_len = CIPSO_V4_OPT_LEN_MAX; 2234 u32 opt_len; 2235 int len_delta; 2236 2237 ret_val = cipso_v4_genopt(buf, buf_len, doi_def, secattr); 2238 if (ret_val < 0) 2239 return ret_val; 2240 buf_len = ret_val; 2241 opt_len = (buf_len + 3) & ~3; 2242 2243 /* we overwrite any existing options to ensure that we have enough 2244 * room for the CIPSO option, the reason is that we _need_ to guarantee 2245 * that the security label is applied to the packet - we do the same 2246 * thing when using the socket options and it hasn't caused a problem, 2247 * if we need to we can always revisit this choice later */ 2248 2249 len_delta = opt_len - opt->optlen; 2250 /* if we don't ensure enough headroom we could panic on the skb_push() 2251 * call below so make sure we have enough, we are also "mangling" the 2252 * packet so we should probably do a copy-on-write call anyway */ 2253 ret_val = skb_cow(skb, skb_headroom(skb) + len_delta); 2254 if (ret_val < 0) 2255 return ret_val; 2256 2257 if (len_delta > 0) { 2258 /* we assume that the header + opt->optlen have already been 2259 * "pushed" in ip_options_build() or similar */ 2260 iph = ip_hdr(skb); 2261 skb_push(skb, len_delta); 2262 memmove((char *)iph - len_delta, iph, iph->ihl << 2); 2263 skb_reset_network_header(skb); 2264 iph = ip_hdr(skb); 2265 } else if (len_delta < 0) { 2266 iph = ip_hdr(skb); 2267 memset(iph + 1, IPOPT_NOP, opt->optlen); 2268 } else 2269 iph = ip_hdr(skb); 2270 2271 if (opt->optlen > 0) 2272 memset(opt, 0, sizeof(*opt)); 2273 opt->optlen = opt_len; 2274 opt->cipso = sizeof(struct iphdr); 2275 opt->is_changed = 1; 2276 2277 /* we have to do the following because we are being called from a 2278 * netfilter hook which means the packet already has had the header 2279 * fields populated and the checksum calculated - yes this means we 2280 * are doing more work than needed but we do it to keep the core 2281 * stack clean and tidy */ 2282 memcpy(iph + 1, buf, buf_len); 2283 if (opt_len > buf_len) 2284 memset((char *)(iph + 1) + buf_len, 0, opt_len - buf_len); 2285 if (len_delta != 0) { 2286 iph->ihl = 5 + (opt_len >> 2); 2287 iph->tot_len = htons(skb->len); 2288 } 2289 ip_send_check(iph); 2290 2291 return 0; 2292 } 2293 2294 /** 2295 * cipso_v4_skbuff_delattr - Delete any CIPSO options from a packet 2296 * @skb: the packet 2297 * 2298 * Description: 2299 * Removes any and all CIPSO options from the given packet. Returns zero on 2300 * success, negative values on failure. 2301 * 2302 */ 2303 int cipso_v4_skbuff_delattr(struct sk_buff *skb) 2304 { 2305 int ret_val; 2306 struct iphdr *iph; 2307 struct ip_options *opt = &IPCB(skb)->opt; 2308 unsigned char *cipso_ptr; 2309 2310 if (opt->cipso == 0) 2311 return 0; 2312 2313 /* since we are changing the packet we should make a copy */ 2314 ret_val = skb_cow(skb, skb_headroom(skb)); 2315 if (ret_val < 0) 2316 return ret_val; 2317 2318 /* the easiest thing to do is just replace the cipso option with noop 2319 * options since we don't change the size of the packet, although we 2320 * still need to recalculate the checksum */ 2321 2322 iph = ip_hdr(skb); 2323 cipso_ptr = (unsigned char *)iph + opt->cipso; 2324 memset(cipso_ptr, IPOPT_NOOP, cipso_ptr[1]); 2325 opt->cipso = 0; 2326 opt->is_changed = 1; 2327 2328 ip_send_check(iph); 2329 2330 return 0; 2331 } 2332 2333 /* 2334 * Setup Functions 2335 */ 2336 2337 /** 2338 * cipso_v4_init - Initialize the CIPSO module 2339 * 2340 * Description: 2341 * Initialize the CIPSO module and prepare it for use. Returns zero on success 2342 * and negative values on failure. 2343 * 2344 */ 2345 static int __init cipso_v4_init(void) 2346 { 2347 int ret_val; 2348 2349 ret_val = cipso_v4_cache_init(); 2350 if (ret_val != 0) 2351 panic("Failed to initialize the CIPSO/IPv4 cache (%d)\n", 2352 ret_val); 2353 2354 return 0; 2355 } 2356 2357 subsys_initcall(cipso_v4_init); 2358