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 <asm/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 struct cipso_v4_map_cache_entry { 76 u32 hash; 77 unsigned char *key; 78 size_t key_len; 79 80 struct netlbl_lsm_cache *lsm_data; 81 82 u32 activity; 83 struct list_head list; 84 }; 85 static struct cipso_v4_map_cache_bkt *cipso_v4_cache = NULL; 86 87 /* Restricted bitmap (tag #1) flags */ 88 int cipso_v4_rbm_optfmt = 0; 89 int cipso_v4_rbm_strictvalid = 1; 90 91 /* 92 * Protocol Constants 93 */ 94 95 /* Maximum size of the CIPSO IP option, derived from the fact that the maximum 96 * IPv4 header size is 60 bytes and the base IPv4 header is 20 bytes long. */ 97 #define CIPSO_V4_OPT_LEN_MAX 40 98 99 /* Length of the base CIPSO option, this includes the option type (1 byte), the 100 * option length (1 byte), and the DOI (4 bytes). */ 101 #define CIPSO_V4_HDR_LEN 6 102 103 /* Base length of the restrictive category bitmap tag (tag #1). */ 104 #define CIPSO_V4_TAG_RBM_BLEN 4 105 106 /* Base length of the enumerated category tag (tag #2). */ 107 #define CIPSO_V4_TAG_ENUM_BLEN 4 108 109 /* Base length of the ranged categories bitmap tag (tag #5). */ 110 #define CIPSO_V4_TAG_RNG_BLEN 4 111 /* The maximum number of category ranges permitted in the ranged category tag 112 * (tag #5). You may note that the IETF draft states that the maximum number 113 * of category ranges is 7, but if the low end of the last category range is 114 * zero then it is possible to fit 8 category ranges because the zero should 115 * be omitted. */ 116 #define CIPSO_V4_TAG_RNG_CAT_MAX 8 117 118 /* Base length of the local tag (non-standard tag). 119 * Tag definition (may change between kernel versions) 120 * 121 * 0 8 16 24 32 122 * +----------+----------+----------+----------+ 123 * | 10000000 | 00000110 | 32-bit secid value | 124 * +----------+----------+----------+----------+ 125 * | in (host byte order)| 126 * +----------+----------+ 127 * 128 */ 129 #define CIPSO_V4_TAG_LOC_BLEN 6 130 131 /* 132 * Helper Functions 133 */ 134 135 /** 136 * cipso_v4_bitmap_walk - Walk a bitmap looking for a bit 137 * @bitmap: the bitmap 138 * @bitmap_len: length in bits 139 * @offset: starting offset 140 * @state: if non-zero, look for a set (1) bit else look for a cleared (0) bit 141 * 142 * Description: 143 * Starting at @offset, walk the bitmap from left to right until either the 144 * desired bit is found or we reach the end. Return the bit offset, -1 if 145 * not found, or -2 if error. 146 */ 147 static int cipso_v4_bitmap_walk(const unsigned char *bitmap, 148 u32 bitmap_len, 149 u32 offset, 150 u8 state) 151 { 152 u32 bit_spot; 153 u32 byte_offset; 154 unsigned char bitmask; 155 unsigned char byte; 156 157 /* gcc always rounds to zero when doing integer division */ 158 byte_offset = offset / 8; 159 byte = bitmap[byte_offset]; 160 bit_spot = offset; 161 bitmask = 0x80 >> (offset % 8); 162 163 while (bit_spot < bitmap_len) { 164 if ((state && (byte & bitmask) == bitmask) || 165 (state == 0 && (byte & bitmask) == 0)) 166 return bit_spot; 167 168 bit_spot++; 169 bitmask >>= 1; 170 if (bitmask == 0) { 171 byte = bitmap[++byte_offset]; 172 bitmask = 0x80; 173 } 174 } 175 176 return -1; 177 } 178 179 /** 180 * cipso_v4_bitmap_setbit - Sets a single bit in a bitmap 181 * @bitmap: the bitmap 182 * @bit: the bit 183 * @state: if non-zero, set the bit (1) else clear the bit (0) 184 * 185 * Description: 186 * Set a single bit in the bitmask. Returns zero on success, negative values 187 * on error. 188 */ 189 static void cipso_v4_bitmap_setbit(unsigned char *bitmap, 190 u32 bit, 191 u8 state) 192 { 193 u32 byte_spot; 194 u8 bitmask; 195 196 /* gcc always rounds to zero when doing integer division */ 197 byte_spot = bit / 8; 198 bitmask = 0x80 >> (bit % 8); 199 if (state) 200 bitmap[byte_spot] |= bitmask; 201 else 202 bitmap[byte_spot] &= ~bitmask; 203 } 204 205 /** 206 * cipso_v4_cache_entry_free - Frees a cache entry 207 * @entry: the entry to free 208 * 209 * Description: 210 * This function frees the memory associated with a cache entry including the 211 * LSM cache data if there are no longer any users, i.e. reference count == 0. 212 * 213 */ 214 static void cipso_v4_cache_entry_free(struct cipso_v4_map_cache_entry *entry) 215 { 216 if (entry->lsm_data) 217 netlbl_secattr_cache_free(entry->lsm_data); 218 kfree(entry->key); 219 kfree(entry); 220 } 221 222 /** 223 * cipso_v4_map_cache_hash - Hashing function for the CIPSO cache 224 * @key: the hash key 225 * @key_len: the length of the key in bytes 226 * 227 * Description: 228 * The CIPSO tag hashing function. Returns a 32-bit hash value. 229 * 230 */ 231 static u32 cipso_v4_map_cache_hash(const unsigned char *key, u32 key_len) 232 { 233 return jhash(key, key_len, 0); 234 } 235 236 /* 237 * Label Mapping Cache Functions 238 */ 239 240 /** 241 * cipso_v4_cache_init - Initialize the CIPSO cache 242 * 243 * Description: 244 * Initializes the CIPSO label mapping cache, this function should be called 245 * before any of the other functions defined in this file. Returns zero on 246 * success, negative values on error. 247 * 248 */ 249 static int cipso_v4_cache_init(void) 250 { 251 u32 iter; 252 253 cipso_v4_cache = kcalloc(CIPSO_V4_CACHE_BUCKETS, 254 sizeof(struct cipso_v4_map_cache_bkt), 255 GFP_KERNEL); 256 if (cipso_v4_cache == NULL) 257 return -ENOMEM; 258 259 for (iter = 0; iter < CIPSO_V4_CACHE_BUCKETS; iter++) { 260 spin_lock_init(&cipso_v4_cache[iter].lock); 261 cipso_v4_cache[iter].size = 0; 262 INIT_LIST_HEAD(&cipso_v4_cache[iter].list); 263 } 264 265 return 0; 266 } 267 268 /** 269 * cipso_v4_cache_invalidate - Invalidates the current CIPSO cache 270 * 271 * Description: 272 * Invalidates and frees any entries in the CIPSO cache. Returns zero on 273 * success and negative values on failure. 274 * 275 */ 276 void cipso_v4_cache_invalidate(void) 277 { 278 struct cipso_v4_map_cache_entry *entry, *tmp_entry; 279 u32 iter; 280 281 for (iter = 0; iter < CIPSO_V4_CACHE_BUCKETS; iter++) { 282 spin_lock_bh(&cipso_v4_cache[iter].lock); 283 list_for_each_entry_safe(entry, 284 tmp_entry, 285 &cipso_v4_cache[iter].list, list) { 286 list_del(&entry->list); 287 cipso_v4_cache_entry_free(entry); 288 } 289 cipso_v4_cache[iter].size = 0; 290 spin_unlock_bh(&cipso_v4_cache[iter].lock); 291 } 292 } 293 294 /** 295 * cipso_v4_cache_check - Check the CIPSO cache for a label mapping 296 * @key: the buffer to check 297 * @key_len: buffer length in bytes 298 * @secattr: the security attribute struct to use 299 * 300 * Description: 301 * This function checks the cache to see if a label mapping already exists for 302 * the given key. If there is a match then the cache is adjusted and the 303 * @secattr struct is populated with the correct LSM security attributes. The 304 * cache is adjusted in the following manner if the entry is not already the 305 * first in the cache bucket: 306 * 307 * 1. The cache entry's activity counter is incremented 308 * 2. The previous (higher ranking) entry's activity counter is decremented 309 * 3. If the difference between the two activity counters is geater than 310 * CIPSO_V4_CACHE_REORDERLIMIT the two entries are swapped 311 * 312 * Returns zero on success, -ENOENT for a cache miss, and other negative values 313 * on error. 314 * 315 */ 316 static int cipso_v4_cache_check(const unsigned char *key, 317 u32 key_len, 318 struct netlbl_lsm_secattr *secattr) 319 { 320 u32 bkt; 321 struct cipso_v4_map_cache_entry *entry; 322 struct cipso_v4_map_cache_entry *prev_entry = NULL; 323 u32 hash; 324 325 if (!cipso_v4_cache_enabled) 326 return -ENOENT; 327 328 hash = cipso_v4_map_cache_hash(key, key_len); 329 bkt = hash & (CIPSO_V4_CACHE_BUCKETS - 1); 330 spin_lock_bh(&cipso_v4_cache[bkt].lock); 331 list_for_each_entry(entry, &cipso_v4_cache[bkt].list, list) { 332 if (entry->hash == hash && 333 entry->key_len == key_len && 334 memcmp(entry->key, key, key_len) == 0) { 335 entry->activity += 1; 336 atomic_inc(&entry->lsm_data->refcount); 337 secattr->cache = entry->lsm_data; 338 secattr->flags |= NETLBL_SECATTR_CACHE; 339 secattr->type = NETLBL_NLTYPE_CIPSOV4; 340 if (prev_entry == NULL) { 341 spin_unlock_bh(&cipso_v4_cache[bkt].lock); 342 return 0; 343 } 344 345 if (prev_entry->activity > 0) 346 prev_entry->activity -= 1; 347 if (entry->activity > prev_entry->activity && 348 entry->activity - prev_entry->activity > 349 CIPSO_V4_CACHE_REORDERLIMIT) { 350 __list_del(entry->list.prev, entry->list.next); 351 __list_add(&entry->list, 352 prev_entry->list.prev, 353 &prev_entry->list); 354 } 355 356 spin_unlock_bh(&cipso_v4_cache[bkt].lock); 357 return 0; 358 } 359 prev_entry = entry; 360 } 361 spin_unlock_bh(&cipso_v4_cache[bkt].lock); 362 363 return -ENOENT; 364 } 365 366 /** 367 * cipso_v4_cache_add - Add an entry to the CIPSO cache 368 * @skb: the packet 369 * @secattr: the packet's security attributes 370 * 371 * Description: 372 * Add a new entry into the CIPSO label mapping cache. Add the new entry to 373 * head of the cache bucket's list, if the cache bucket is out of room remove 374 * the last entry in the list first. It is important to note that there is 375 * currently no checking for duplicate keys. Returns zero on success, 376 * negative values on failure. 377 * 378 */ 379 int cipso_v4_cache_add(const struct sk_buff *skb, 380 const struct netlbl_lsm_secattr *secattr) 381 { 382 int ret_val = -EPERM; 383 u32 bkt; 384 struct cipso_v4_map_cache_entry *entry = NULL; 385 struct cipso_v4_map_cache_entry *old_entry = NULL; 386 unsigned char *cipso_ptr; 387 u32 cipso_ptr_len; 388 389 if (!cipso_v4_cache_enabled || cipso_v4_cache_bucketsize <= 0) 390 return 0; 391 392 cipso_ptr = CIPSO_V4_OPTPTR(skb); 393 cipso_ptr_len = cipso_ptr[1]; 394 395 entry = kzalloc(sizeof(*entry), GFP_ATOMIC); 396 if (entry == NULL) 397 return -ENOMEM; 398 entry->key = kmemdup(cipso_ptr, cipso_ptr_len, GFP_ATOMIC); 399 if (entry->key == NULL) { 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) != NULL) { 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 != NULL) { 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 * @entry: the entry's RCU field 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 == NULL) 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 == NULL) { 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 != NULL) { 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 == NULL) 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 == NULL) 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_validate - Validate a CIPSO option 1581 * @option: the start of the option, on error it is set to point to the error 1582 * 1583 * Description: 1584 * This routine is called to validate a CIPSO option, it checks all of the 1585 * fields to ensure that they are at least valid, see the draft snippet below 1586 * for details. If the option is valid then a zero value is returned and 1587 * the value of @option is unchanged. If the option is invalid then a 1588 * non-zero value is returned and @option is adjusted to point to the 1589 * offending portion of the option. From the IETF draft ... 1590 * 1591 * "If any field within the CIPSO options, such as the DOI identifier, is not 1592 * recognized the IP datagram is discarded and an ICMP 'parameter problem' 1593 * (type 12) is generated and returned. The ICMP code field is set to 'bad 1594 * parameter' (code 0) and the pointer is set to the start of the CIPSO field 1595 * that is unrecognized." 1596 * 1597 */ 1598 int cipso_v4_validate(const struct sk_buff *skb, unsigned char **option) 1599 { 1600 unsigned char *opt = *option; 1601 unsigned char *tag; 1602 unsigned char opt_iter; 1603 unsigned char err_offset = 0; 1604 u8 opt_len; 1605 u8 tag_len; 1606 struct cipso_v4_doi *doi_def = NULL; 1607 u32 tag_iter; 1608 1609 /* caller already checks for length values that are too large */ 1610 opt_len = opt[1]; 1611 if (opt_len < 8) { 1612 err_offset = 1; 1613 goto validate_return; 1614 } 1615 1616 rcu_read_lock(); 1617 doi_def = cipso_v4_doi_search(get_unaligned_be32(&opt[2])); 1618 if (doi_def == NULL) { 1619 err_offset = 2; 1620 goto validate_return_locked; 1621 } 1622 1623 opt_iter = CIPSO_V4_HDR_LEN; 1624 tag = opt + opt_iter; 1625 while (opt_iter < opt_len) { 1626 for (tag_iter = 0; doi_def->tags[tag_iter] != tag[0];) 1627 if (doi_def->tags[tag_iter] == CIPSO_V4_TAG_INVALID || 1628 ++tag_iter == CIPSO_V4_TAG_MAXCNT) { 1629 err_offset = opt_iter; 1630 goto validate_return_locked; 1631 } 1632 1633 tag_len = tag[1]; 1634 if (tag_len > (opt_len - opt_iter)) { 1635 err_offset = opt_iter + 1; 1636 goto validate_return_locked; 1637 } 1638 1639 switch (tag[0]) { 1640 case CIPSO_V4_TAG_RBITMAP: 1641 if (tag_len < CIPSO_V4_TAG_RBM_BLEN) { 1642 err_offset = opt_iter + 1; 1643 goto validate_return_locked; 1644 } 1645 1646 /* We are already going to do all the verification 1647 * necessary at the socket layer so from our point of 1648 * view it is safe to turn these checks off (and less 1649 * work), however, the CIPSO draft says we should do 1650 * all the CIPSO validations here but it doesn't 1651 * really specify _exactly_ what we need to validate 1652 * ... so, just make it a sysctl tunable. */ 1653 if (cipso_v4_rbm_strictvalid) { 1654 if (cipso_v4_map_lvl_valid(doi_def, 1655 tag[3]) < 0) { 1656 err_offset = opt_iter + 3; 1657 goto validate_return_locked; 1658 } 1659 if (tag_len > CIPSO_V4_TAG_RBM_BLEN && 1660 cipso_v4_map_cat_rbm_valid(doi_def, 1661 &tag[4], 1662 tag_len - 4) < 0) { 1663 err_offset = opt_iter + 4; 1664 goto validate_return_locked; 1665 } 1666 } 1667 break; 1668 case CIPSO_V4_TAG_ENUM: 1669 if (tag_len < CIPSO_V4_TAG_ENUM_BLEN) { 1670 err_offset = opt_iter + 1; 1671 goto validate_return_locked; 1672 } 1673 1674 if (cipso_v4_map_lvl_valid(doi_def, 1675 tag[3]) < 0) { 1676 err_offset = opt_iter + 3; 1677 goto validate_return_locked; 1678 } 1679 if (tag_len > CIPSO_V4_TAG_ENUM_BLEN && 1680 cipso_v4_map_cat_enum_valid(doi_def, 1681 &tag[4], 1682 tag_len - 4) < 0) { 1683 err_offset = opt_iter + 4; 1684 goto validate_return_locked; 1685 } 1686 break; 1687 case CIPSO_V4_TAG_RANGE: 1688 if (tag_len < CIPSO_V4_TAG_RNG_BLEN) { 1689 err_offset = opt_iter + 1; 1690 goto validate_return_locked; 1691 } 1692 1693 if (cipso_v4_map_lvl_valid(doi_def, 1694 tag[3]) < 0) { 1695 err_offset = opt_iter + 3; 1696 goto validate_return_locked; 1697 } 1698 if (tag_len > CIPSO_V4_TAG_RNG_BLEN && 1699 cipso_v4_map_cat_rng_valid(doi_def, 1700 &tag[4], 1701 tag_len - 4) < 0) { 1702 err_offset = opt_iter + 4; 1703 goto validate_return_locked; 1704 } 1705 break; 1706 case CIPSO_V4_TAG_LOCAL: 1707 /* This is a non-standard tag that we only allow for 1708 * local connections, so if the incoming interface is 1709 * not the loopback device drop the packet. Further, 1710 * there is no legitimate reason for setting this from 1711 * userspace so reject it if skb is NULL. */ 1712 if (skb == NULL || !(skb->dev->flags & IFF_LOOPBACK)) { 1713 err_offset = opt_iter; 1714 goto validate_return_locked; 1715 } 1716 if (tag_len != CIPSO_V4_TAG_LOC_BLEN) { 1717 err_offset = opt_iter + 1; 1718 goto validate_return_locked; 1719 } 1720 break; 1721 default: 1722 err_offset = opt_iter; 1723 goto validate_return_locked; 1724 } 1725 1726 tag += tag_len; 1727 opt_iter += tag_len; 1728 } 1729 1730 validate_return_locked: 1731 rcu_read_unlock(); 1732 validate_return: 1733 *option = opt + err_offset; 1734 return err_offset; 1735 } 1736 1737 /** 1738 * cipso_v4_error - Send the correct response for a bad packet 1739 * @skb: the packet 1740 * @error: the error code 1741 * @gateway: CIPSO gateway flag 1742 * 1743 * Description: 1744 * Based on the error code given in @error, send an ICMP error message back to 1745 * the originating host. From the IETF draft ... 1746 * 1747 * "If the contents of the CIPSO [option] are valid but the security label is 1748 * outside of the configured host or port label range, the datagram is 1749 * discarded and an ICMP 'destination unreachable' (type 3) is generated and 1750 * returned. The code field of the ICMP is set to 'communication with 1751 * destination network administratively prohibited' (code 9) or to 1752 * 'communication with destination host administratively prohibited' 1753 * (code 10). The value of the code is dependent on whether the originator 1754 * of the ICMP message is acting as a CIPSO host or a CIPSO gateway. The 1755 * recipient of the ICMP message MUST be able to handle either value. The 1756 * same procedure is performed if a CIPSO [option] can not be added to an 1757 * IP packet because it is too large to fit in the IP options area." 1758 * 1759 * "If the error is triggered by receipt of an ICMP message, the message is 1760 * discarded and no response is permitted (consistent with general ICMP 1761 * processing rules)." 1762 * 1763 */ 1764 void cipso_v4_error(struct sk_buff *skb, int error, u32 gateway) 1765 { 1766 if (ip_hdr(skb)->protocol == IPPROTO_ICMP || error != -EACCES) 1767 return; 1768 1769 if (gateway) 1770 icmp_send(skb, ICMP_DEST_UNREACH, ICMP_NET_ANO, 0); 1771 else 1772 icmp_send(skb, ICMP_DEST_UNREACH, ICMP_HOST_ANO, 0); 1773 } 1774 1775 /** 1776 * cipso_v4_genopt - Generate a CIPSO option 1777 * @buf: the option buffer 1778 * @buf_len: the size of opt_buf 1779 * @doi_def: the CIPSO DOI to use 1780 * @secattr: the security attributes 1781 * 1782 * Description: 1783 * Generate a CIPSO option using the DOI definition and security attributes 1784 * passed to the function. Returns the length of the option on success and 1785 * negative values on failure. 1786 * 1787 */ 1788 static int cipso_v4_genopt(unsigned char *buf, u32 buf_len, 1789 const struct cipso_v4_doi *doi_def, 1790 const struct netlbl_lsm_secattr *secattr) 1791 { 1792 int ret_val; 1793 u32 iter; 1794 1795 if (buf_len <= CIPSO_V4_HDR_LEN) 1796 return -ENOSPC; 1797 1798 /* XXX - This code assumes only one tag per CIPSO option which isn't 1799 * really a good assumption to make but since we only support the MAC 1800 * tags right now it is a safe assumption. */ 1801 iter = 0; 1802 do { 1803 memset(buf, 0, buf_len); 1804 switch (doi_def->tags[iter]) { 1805 case CIPSO_V4_TAG_RBITMAP: 1806 ret_val = cipso_v4_gentag_rbm(doi_def, 1807 secattr, 1808 &buf[CIPSO_V4_HDR_LEN], 1809 buf_len - CIPSO_V4_HDR_LEN); 1810 break; 1811 case CIPSO_V4_TAG_ENUM: 1812 ret_val = cipso_v4_gentag_enum(doi_def, 1813 secattr, 1814 &buf[CIPSO_V4_HDR_LEN], 1815 buf_len - CIPSO_V4_HDR_LEN); 1816 break; 1817 case CIPSO_V4_TAG_RANGE: 1818 ret_val = cipso_v4_gentag_rng(doi_def, 1819 secattr, 1820 &buf[CIPSO_V4_HDR_LEN], 1821 buf_len - CIPSO_V4_HDR_LEN); 1822 break; 1823 case CIPSO_V4_TAG_LOCAL: 1824 ret_val = cipso_v4_gentag_loc(doi_def, 1825 secattr, 1826 &buf[CIPSO_V4_HDR_LEN], 1827 buf_len - CIPSO_V4_HDR_LEN); 1828 break; 1829 default: 1830 return -EPERM; 1831 } 1832 1833 iter++; 1834 } while (ret_val < 0 && 1835 iter < CIPSO_V4_TAG_MAXCNT && 1836 doi_def->tags[iter] != CIPSO_V4_TAG_INVALID); 1837 if (ret_val < 0) 1838 return ret_val; 1839 cipso_v4_gentag_hdr(doi_def, buf, ret_val); 1840 return CIPSO_V4_HDR_LEN + ret_val; 1841 } 1842 1843 /** 1844 * cipso_v4_sock_setattr - Add a CIPSO option to a socket 1845 * @sk: the socket 1846 * @doi_def: the CIPSO DOI to use 1847 * @secattr: the specific security attributes of the socket 1848 * 1849 * Description: 1850 * Set the CIPSO option on the given socket using the DOI definition and 1851 * security attributes passed to the function. This function requires 1852 * exclusive access to @sk, which means it either needs to be in the 1853 * process of being created or locked. Returns zero on success and negative 1854 * values on failure. 1855 * 1856 */ 1857 int cipso_v4_sock_setattr(struct sock *sk, 1858 const struct cipso_v4_doi *doi_def, 1859 const struct netlbl_lsm_secattr *secattr) 1860 { 1861 int ret_val = -EPERM; 1862 unsigned char *buf = NULL; 1863 u32 buf_len; 1864 u32 opt_len; 1865 struct ip_options_rcu *old, *opt = NULL; 1866 struct inet_sock *sk_inet; 1867 struct inet_connection_sock *sk_conn; 1868 1869 /* In the case of sock_create_lite(), the sock->sk field is not 1870 * defined yet but it is not a problem as the only users of these 1871 * "lite" PF_INET sockets are functions which do an accept() call 1872 * afterwards so we will label the socket as part of the accept(). */ 1873 if (sk == NULL) 1874 return 0; 1875 1876 /* We allocate the maximum CIPSO option size here so we are probably 1877 * being a little wasteful, but it makes our life _much_ easier later 1878 * on and after all we are only talking about 40 bytes. */ 1879 buf_len = CIPSO_V4_OPT_LEN_MAX; 1880 buf = kmalloc(buf_len, GFP_ATOMIC); 1881 if (buf == NULL) { 1882 ret_val = -ENOMEM; 1883 goto socket_setattr_failure; 1884 } 1885 1886 ret_val = cipso_v4_genopt(buf, buf_len, doi_def, secattr); 1887 if (ret_val < 0) 1888 goto socket_setattr_failure; 1889 buf_len = ret_val; 1890 1891 /* We can't use ip_options_get() directly because it makes a call to 1892 * ip_options_get_alloc() which allocates memory with GFP_KERNEL and 1893 * we won't always have CAP_NET_RAW even though we _always_ want to 1894 * set the IPOPT_CIPSO option. */ 1895 opt_len = (buf_len + 3) & ~3; 1896 opt = kzalloc(sizeof(*opt) + opt_len, GFP_ATOMIC); 1897 if (opt == NULL) { 1898 ret_val = -ENOMEM; 1899 goto socket_setattr_failure; 1900 } 1901 memcpy(opt->opt.__data, buf, buf_len); 1902 opt->opt.optlen = opt_len; 1903 opt->opt.cipso = sizeof(struct iphdr); 1904 kfree(buf); 1905 buf = NULL; 1906 1907 sk_inet = inet_sk(sk); 1908 1909 old = rcu_dereference_protected(sk_inet->inet_opt, sock_owned_by_user(sk)); 1910 if (sk_inet->is_icsk) { 1911 sk_conn = inet_csk(sk); 1912 if (old) 1913 sk_conn->icsk_ext_hdr_len -= old->opt.optlen; 1914 sk_conn->icsk_ext_hdr_len += opt->opt.optlen; 1915 sk_conn->icsk_sync_mss(sk, sk_conn->icsk_pmtu_cookie); 1916 } 1917 rcu_assign_pointer(sk_inet->inet_opt, opt); 1918 if (old) 1919 kfree_rcu(old, rcu); 1920 1921 return 0; 1922 1923 socket_setattr_failure: 1924 kfree(buf); 1925 kfree(opt); 1926 return ret_val; 1927 } 1928 1929 /** 1930 * cipso_v4_req_setattr - Add a CIPSO option to a connection request socket 1931 * @req: the connection request socket 1932 * @doi_def: the CIPSO DOI to use 1933 * @secattr: the specific security attributes of the socket 1934 * 1935 * Description: 1936 * Set the CIPSO option on the given socket using the DOI definition and 1937 * security attributes passed to the function. Returns zero on success and 1938 * negative values on failure. 1939 * 1940 */ 1941 int cipso_v4_req_setattr(struct request_sock *req, 1942 const struct cipso_v4_doi *doi_def, 1943 const struct netlbl_lsm_secattr *secattr) 1944 { 1945 int ret_val = -EPERM; 1946 unsigned char *buf = NULL; 1947 u32 buf_len; 1948 u32 opt_len; 1949 struct ip_options_rcu *opt = NULL; 1950 struct inet_request_sock *req_inet; 1951 1952 /* We allocate the maximum CIPSO option size here so we are probably 1953 * being a little wasteful, but it makes our life _much_ easier later 1954 * on and after all we are only talking about 40 bytes. */ 1955 buf_len = CIPSO_V4_OPT_LEN_MAX; 1956 buf = kmalloc(buf_len, GFP_ATOMIC); 1957 if (buf == NULL) { 1958 ret_val = -ENOMEM; 1959 goto req_setattr_failure; 1960 } 1961 1962 ret_val = cipso_v4_genopt(buf, buf_len, doi_def, secattr); 1963 if (ret_val < 0) 1964 goto req_setattr_failure; 1965 buf_len = ret_val; 1966 1967 /* We can't use ip_options_get() directly because it makes a call to 1968 * ip_options_get_alloc() which allocates memory with GFP_KERNEL and 1969 * we won't always have CAP_NET_RAW even though we _always_ want to 1970 * set the IPOPT_CIPSO option. */ 1971 opt_len = (buf_len + 3) & ~3; 1972 opt = kzalloc(sizeof(*opt) + opt_len, GFP_ATOMIC); 1973 if (opt == NULL) { 1974 ret_val = -ENOMEM; 1975 goto req_setattr_failure; 1976 } 1977 memcpy(opt->opt.__data, buf, buf_len); 1978 opt->opt.optlen = opt_len; 1979 opt->opt.cipso = sizeof(struct iphdr); 1980 kfree(buf); 1981 buf = NULL; 1982 1983 req_inet = inet_rsk(req); 1984 opt = xchg(&req_inet->opt, opt); 1985 if (opt) 1986 kfree_rcu(opt, rcu); 1987 1988 return 0; 1989 1990 req_setattr_failure: 1991 kfree(buf); 1992 kfree(opt); 1993 return ret_val; 1994 } 1995 1996 /** 1997 * cipso_v4_delopt - Delete the CIPSO option from a set of IP options 1998 * @opt_ptr: IP option pointer 1999 * 2000 * Description: 2001 * Deletes the CIPSO IP option from a set of IP options and makes the necessary 2002 * adjustments to the IP option structure. Returns zero on success, negative 2003 * values on failure. 2004 * 2005 */ 2006 static int cipso_v4_delopt(struct ip_options_rcu **opt_ptr) 2007 { 2008 int hdr_delta = 0; 2009 struct ip_options_rcu *opt = *opt_ptr; 2010 2011 if (opt->opt.srr || opt->opt.rr || opt->opt.ts || opt->opt.router_alert) { 2012 u8 cipso_len; 2013 u8 cipso_off; 2014 unsigned char *cipso_ptr; 2015 int iter; 2016 int optlen_new; 2017 2018 cipso_off = opt->opt.cipso - sizeof(struct iphdr); 2019 cipso_ptr = &opt->opt.__data[cipso_off]; 2020 cipso_len = cipso_ptr[1]; 2021 2022 if (opt->opt.srr > opt->opt.cipso) 2023 opt->opt.srr -= cipso_len; 2024 if (opt->opt.rr > opt->opt.cipso) 2025 opt->opt.rr -= cipso_len; 2026 if (opt->opt.ts > opt->opt.cipso) 2027 opt->opt.ts -= cipso_len; 2028 if (opt->opt.router_alert > opt->opt.cipso) 2029 opt->opt.router_alert -= cipso_len; 2030 opt->opt.cipso = 0; 2031 2032 memmove(cipso_ptr, cipso_ptr + cipso_len, 2033 opt->opt.optlen - cipso_off - cipso_len); 2034 2035 /* determining the new total option length is tricky because of 2036 * the padding necessary, the only thing i can think to do at 2037 * this point is walk the options one-by-one, skipping the 2038 * padding at the end to determine the actual option size and 2039 * from there we can determine the new total option length */ 2040 iter = 0; 2041 optlen_new = 0; 2042 while (iter < opt->opt.optlen) 2043 if (opt->opt.__data[iter] != IPOPT_NOP) { 2044 iter += opt->opt.__data[iter + 1]; 2045 optlen_new = iter; 2046 } else 2047 iter++; 2048 hdr_delta = opt->opt.optlen; 2049 opt->opt.optlen = (optlen_new + 3) & ~3; 2050 hdr_delta -= opt->opt.optlen; 2051 } else { 2052 /* only the cipso option was present on the socket so we can 2053 * remove the entire option struct */ 2054 *opt_ptr = NULL; 2055 hdr_delta = opt->opt.optlen; 2056 kfree_rcu(opt, rcu); 2057 } 2058 2059 return hdr_delta; 2060 } 2061 2062 /** 2063 * cipso_v4_sock_delattr - Delete the CIPSO option from a socket 2064 * @sk: the socket 2065 * 2066 * Description: 2067 * Removes the CIPSO option from a socket, if present. 2068 * 2069 */ 2070 void cipso_v4_sock_delattr(struct sock *sk) 2071 { 2072 int hdr_delta; 2073 struct ip_options_rcu *opt; 2074 struct inet_sock *sk_inet; 2075 2076 sk_inet = inet_sk(sk); 2077 opt = rcu_dereference_protected(sk_inet->inet_opt, 1); 2078 if (opt == NULL || opt->opt.cipso == 0) 2079 return; 2080 2081 hdr_delta = cipso_v4_delopt(&sk_inet->inet_opt); 2082 if (sk_inet->is_icsk && hdr_delta > 0) { 2083 struct inet_connection_sock *sk_conn = inet_csk(sk); 2084 sk_conn->icsk_ext_hdr_len -= hdr_delta; 2085 sk_conn->icsk_sync_mss(sk, sk_conn->icsk_pmtu_cookie); 2086 } 2087 } 2088 2089 /** 2090 * cipso_v4_req_delattr - Delete the CIPSO option from a request socket 2091 * @reg: the request socket 2092 * 2093 * Description: 2094 * Removes the CIPSO option from a request socket, if present. 2095 * 2096 */ 2097 void cipso_v4_req_delattr(struct request_sock *req) 2098 { 2099 struct ip_options_rcu *opt; 2100 struct inet_request_sock *req_inet; 2101 2102 req_inet = inet_rsk(req); 2103 opt = req_inet->opt; 2104 if (opt == NULL || opt->opt.cipso == 0) 2105 return; 2106 2107 cipso_v4_delopt(&req_inet->opt); 2108 } 2109 2110 /** 2111 * cipso_v4_getattr - Helper function for the cipso_v4_*_getattr functions 2112 * @cipso: the CIPSO v4 option 2113 * @secattr: the security attributes 2114 * 2115 * Description: 2116 * Inspect @cipso and return the security attributes in @secattr. Returns zero 2117 * on success and negative values on failure. 2118 * 2119 */ 2120 static int cipso_v4_getattr(const unsigned char *cipso, 2121 struct netlbl_lsm_secattr *secattr) 2122 { 2123 int ret_val = -ENOMSG; 2124 u32 doi; 2125 struct cipso_v4_doi *doi_def; 2126 2127 if (cipso_v4_cache_check(cipso, cipso[1], secattr) == 0) 2128 return 0; 2129 2130 doi = get_unaligned_be32(&cipso[2]); 2131 rcu_read_lock(); 2132 doi_def = cipso_v4_doi_search(doi); 2133 if (doi_def == NULL) 2134 goto getattr_return; 2135 /* XXX - This code assumes only one tag per CIPSO option which isn't 2136 * really a good assumption to make but since we only support the MAC 2137 * tags right now it is a safe assumption. */ 2138 switch (cipso[6]) { 2139 case CIPSO_V4_TAG_RBITMAP: 2140 ret_val = cipso_v4_parsetag_rbm(doi_def, &cipso[6], secattr); 2141 break; 2142 case CIPSO_V4_TAG_ENUM: 2143 ret_val = cipso_v4_parsetag_enum(doi_def, &cipso[6], secattr); 2144 break; 2145 case CIPSO_V4_TAG_RANGE: 2146 ret_val = cipso_v4_parsetag_rng(doi_def, &cipso[6], secattr); 2147 break; 2148 case CIPSO_V4_TAG_LOCAL: 2149 ret_val = cipso_v4_parsetag_loc(doi_def, &cipso[6], secattr); 2150 break; 2151 } 2152 if (ret_val == 0) 2153 secattr->type = NETLBL_NLTYPE_CIPSOV4; 2154 2155 getattr_return: 2156 rcu_read_unlock(); 2157 return ret_val; 2158 } 2159 2160 /** 2161 * cipso_v4_sock_getattr - Get the security attributes from a sock 2162 * @sk: the sock 2163 * @secattr: the security attributes 2164 * 2165 * Description: 2166 * Query @sk to see if there is a CIPSO option attached to the sock and if 2167 * there is return the CIPSO security attributes in @secattr. This function 2168 * requires that @sk be locked, or privately held, but it does not do any 2169 * locking itself. Returns zero on success and negative values on failure. 2170 * 2171 */ 2172 int cipso_v4_sock_getattr(struct sock *sk, struct netlbl_lsm_secattr *secattr) 2173 { 2174 struct ip_options_rcu *opt; 2175 int res = -ENOMSG; 2176 2177 rcu_read_lock(); 2178 opt = rcu_dereference(inet_sk(sk)->inet_opt); 2179 if (opt && opt->opt.cipso) 2180 res = cipso_v4_getattr(opt->opt.__data + 2181 opt->opt.cipso - 2182 sizeof(struct iphdr), 2183 secattr); 2184 rcu_read_unlock(); 2185 return res; 2186 } 2187 2188 /** 2189 * cipso_v4_skbuff_setattr - Set the CIPSO option on a packet 2190 * @skb: the packet 2191 * @secattr: the security attributes 2192 * 2193 * Description: 2194 * Set the CIPSO option on the given packet based on the security attributes. 2195 * Returns a pointer to the IP header on success and NULL on failure. 2196 * 2197 */ 2198 int cipso_v4_skbuff_setattr(struct sk_buff *skb, 2199 const struct cipso_v4_doi *doi_def, 2200 const struct netlbl_lsm_secattr *secattr) 2201 { 2202 int ret_val; 2203 struct iphdr *iph; 2204 struct ip_options *opt = &IPCB(skb)->opt; 2205 unsigned char buf[CIPSO_V4_OPT_LEN_MAX]; 2206 u32 buf_len = CIPSO_V4_OPT_LEN_MAX; 2207 u32 opt_len; 2208 int len_delta; 2209 2210 ret_val = cipso_v4_genopt(buf, buf_len, doi_def, secattr); 2211 if (ret_val < 0) 2212 return ret_val; 2213 buf_len = ret_val; 2214 opt_len = (buf_len + 3) & ~3; 2215 2216 /* we overwrite any existing options to ensure that we have enough 2217 * room for the CIPSO option, the reason is that we _need_ to guarantee 2218 * that the security label is applied to the packet - we do the same 2219 * thing when using the socket options and it hasn't caused a problem, 2220 * if we need to we can always revisit this choice later */ 2221 2222 len_delta = opt_len - opt->optlen; 2223 /* if we don't ensure enough headroom we could panic on the skb_push() 2224 * call below so make sure we have enough, we are also "mangling" the 2225 * packet so we should probably do a copy-on-write call anyway */ 2226 ret_val = skb_cow(skb, skb_headroom(skb) + len_delta); 2227 if (ret_val < 0) 2228 return ret_val; 2229 2230 if (len_delta > 0) { 2231 /* we assume that the header + opt->optlen have already been 2232 * "pushed" in ip_options_build() or similar */ 2233 iph = ip_hdr(skb); 2234 skb_push(skb, len_delta); 2235 memmove((char *)iph - len_delta, iph, iph->ihl << 2); 2236 skb_reset_network_header(skb); 2237 iph = ip_hdr(skb); 2238 } else if (len_delta < 0) { 2239 iph = ip_hdr(skb); 2240 memset(iph + 1, IPOPT_NOP, opt->optlen); 2241 } else 2242 iph = ip_hdr(skb); 2243 2244 if (opt->optlen > 0) 2245 memset(opt, 0, sizeof(*opt)); 2246 opt->optlen = opt_len; 2247 opt->cipso = sizeof(struct iphdr); 2248 opt->is_changed = 1; 2249 2250 /* we have to do the following because we are being called from a 2251 * netfilter hook which means the packet already has had the header 2252 * fields populated and the checksum calculated - yes this means we 2253 * are doing more work than needed but we do it to keep the core 2254 * stack clean and tidy */ 2255 memcpy(iph + 1, buf, buf_len); 2256 if (opt_len > buf_len) 2257 memset((char *)(iph + 1) + buf_len, 0, opt_len - buf_len); 2258 if (len_delta != 0) { 2259 iph->ihl = 5 + (opt_len >> 2); 2260 iph->tot_len = htons(skb->len); 2261 } 2262 ip_send_check(iph); 2263 2264 return 0; 2265 } 2266 2267 /** 2268 * cipso_v4_skbuff_delattr - Delete any CIPSO options from a packet 2269 * @skb: the packet 2270 * 2271 * Description: 2272 * Removes any and all CIPSO options from the given packet. Returns zero on 2273 * success, negative values on failure. 2274 * 2275 */ 2276 int cipso_v4_skbuff_delattr(struct sk_buff *skb) 2277 { 2278 int ret_val; 2279 struct iphdr *iph; 2280 struct ip_options *opt = &IPCB(skb)->opt; 2281 unsigned char *cipso_ptr; 2282 2283 if (opt->cipso == 0) 2284 return 0; 2285 2286 /* since we are changing the packet we should make a copy */ 2287 ret_val = skb_cow(skb, skb_headroom(skb)); 2288 if (ret_val < 0) 2289 return ret_val; 2290 2291 /* the easiest thing to do is just replace the cipso option with noop 2292 * options since we don't change the size of the packet, although we 2293 * still need to recalculate the checksum */ 2294 2295 iph = ip_hdr(skb); 2296 cipso_ptr = (unsigned char *)iph + opt->cipso; 2297 memset(cipso_ptr, IPOPT_NOOP, cipso_ptr[1]); 2298 opt->cipso = 0; 2299 opt->is_changed = 1; 2300 2301 ip_send_check(iph); 2302 2303 return 0; 2304 } 2305 2306 /** 2307 * cipso_v4_skbuff_getattr - Get the security attributes from the CIPSO option 2308 * @skb: the packet 2309 * @secattr: the security attributes 2310 * 2311 * Description: 2312 * Parse the given packet's CIPSO option and return the security attributes. 2313 * Returns zero on success and negative values on failure. 2314 * 2315 */ 2316 int cipso_v4_skbuff_getattr(const struct sk_buff *skb, 2317 struct netlbl_lsm_secattr *secattr) 2318 { 2319 return cipso_v4_getattr(CIPSO_V4_OPTPTR(skb), secattr); 2320 } 2321 2322 /* 2323 * Setup Functions 2324 */ 2325 2326 /** 2327 * cipso_v4_init - Initialize the CIPSO module 2328 * 2329 * Description: 2330 * Initialize the CIPSO module and prepare it for use. Returns zero on success 2331 * and negative values on failure. 2332 * 2333 */ 2334 static int __init cipso_v4_init(void) 2335 { 2336 int ret_val; 2337 2338 ret_val = cipso_v4_cache_init(); 2339 if (ret_val != 0) 2340 panic("Failed to initialize the CIPSO/IPv4 cache (%d)\n", 2341 ret_val); 2342 2343 return 0; 2344 } 2345 2346 subsys_initcall(cipso_v4_init); 2347