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://netlabel.sourceforge.net/files/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, write to the Free Software 35 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA 36 * 37 */ 38 39 #include <linux/init.h> 40 #include <linux/types.h> 41 #include <linux/rcupdate.h> 42 #include <linux/list.h> 43 #include <linux/spinlock.h> 44 #include <linux/string.h> 45 #include <linux/jhash.h> 46 #include <linux/audit.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 <asm/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 possibile 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 return; 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 == NULL) { 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 struct sk_buff *skb, 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 unsigned char *cipso_ptr; 389 u32 cipso_ptr_len; 390 391 if (!cipso_v4_cache_enabled || cipso_v4_cache_bucketsize <= 0) 392 return 0; 393 394 cipso_ptr = CIPSO_V4_OPTPTR(skb); 395 cipso_ptr_len = cipso_ptr[1]; 396 397 entry = kzalloc(sizeof(*entry), GFP_ATOMIC); 398 if (entry == NULL) 399 return -ENOMEM; 400 entry->key = kmemdup(cipso_ptr, cipso_ptr_len, GFP_ATOMIC); 401 if (entry->key == NULL) { 402 ret_val = -ENOMEM; 403 goto cache_add_failure; 404 } 405 entry->key_len = cipso_ptr_len; 406 entry->hash = cipso_v4_map_cache_hash(cipso_ptr, cipso_ptr_len); 407 atomic_inc(&secattr->cache->refcount); 408 entry->lsm_data = secattr->cache; 409 410 bkt = entry->hash & (CIPSO_V4_CACHE_BUCKETS - 1); 411 spin_lock_bh(&cipso_v4_cache[bkt].lock); 412 if (cipso_v4_cache[bkt].size < cipso_v4_cache_bucketsize) { 413 list_add(&entry->list, &cipso_v4_cache[bkt].list); 414 cipso_v4_cache[bkt].size += 1; 415 } else { 416 old_entry = list_entry(cipso_v4_cache[bkt].list.prev, 417 struct cipso_v4_map_cache_entry, list); 418 list_del(&old_entry->list); 419 list_add(&entry->list, &cipso_v4_cache[bkt].list); 420 cipso_v4_cache_entry_free(old_entry); 421 } 422 spin_unlock_bh(&cipso_v4_cache[bkt].lock); 423 424 return 0; 425 426 cache_add_failure: 427 if (entry) 428 cipso_v4_cache_entry_free(entry); 429 return ret_val; 430 } 431 432 /* 433 * DOI List Functions 434 */ 435 436 /** 437 * cipso_v4_doi_search - Searches for a DOI definition 438 * @doi: the DOI to search for 439 * 440 * Description: 441 * Search the DOI definition list for a DOI definition with a DOI value that 442 * matches @doi. The caller is responsibile for calling rcu_read_[un]lock(). 443 * Returns a pointer to the DOI definition on success and NULL on failure. 444 */ 445 static struct cipso_v4_doi *cipso_v4_doi_search(u32 doi) 446 { 447 struct cipso_v4_doi *iter; 448 449 list_for_each_entry_rcu(iter, &cipso_v4_doi_list, list) 450 if (iter->doi == doi && atomic_read(&iter->refcount)) 451 return iter; 452 return NULL; 453 } 454 455 /** 456 * cipso_v4_doi_add - Add a new DOI to the CIPSO protocol engine 457 * @doi_def: the DOI structure 458 * @audit_info: NetLabel audit information 459 * 460 * Description: 461 * The caller defines a new DOI for use by the CIPSO engine and calls this 462 * function to add it to the list of acceptable domains. The caller must 463 * ensure that the mapping table specified in @doi_def->map meets all of the 464 * requirements of the mapping type (see cipso_ipv4.h for details). Returns 465 * zero on success and non-zero on failure. 466 * 467 */ 468 int cipso_v4_doi_add(struct cipso_v4_doi *doi_def, 469 struct netlbl_audit *audit_info) 470 { 471 int ret_val = -EINVAL; 472 u32 iter; 473 u32 doi; 474 u32 doi_type; 475 struct audit_buffer *audit_buf; 476 477 doi = doi_def->doi; 478 doi_type = doi_def->type; 479 480 if (doi_def == NULL || doi_def->doi == CIPSO_V4_DOI_UNKNOWN) 481 goto doi_add_return; 482 for (iter = 0; iter < CIPSO_V4_TAG_MAXCNT; iter++) { 483 switch (doi_def->tags[iter]) { 484 case CIPSO_V4_TAG_RBITMAP: 485 break; 486 case CIPSO_V4_TAG_RANGE: 487 case CIPSO_V4_TAG_ENUM: 488 if (doi_def->type != CIPSO_V4_MAP_PASS) 489 goto doi_add_return; 490 break; 491 case CIPSO_V4_TAG_LOCAL: 492 if (doi_def->type != CIPSO_V4_MAP_LOCAL) 493 goto doi_add_return; 494 break; 495 case CIPSO_V4_TAG_INVALID: 496 if (iter == 0) 497 goto doi_add_return; 498 break; 499 default: 500 goto doi_add_return; 501 } 502 } 503 504 atomic_set(&doi_def->refcount, 1); 505 506 spin_lock(&cipso_v4_doi_list_lock); 507 if (cipso_v4_doi_search(doi_def->doi) != NULL) { 508 spin_unlock(&cipso_v4_doi_list_lock); 509 ret_val = -EEXIST; 510 goto doi_add_return; 511 } 512 list_add_tail_rcu(&doi_def->list, &cipso_v4_doi_list); 513 spin_unlock(&cipso_v4_doi_list_lock); 514 ret_val = 0; 515 516 doi_add_return: 517 audit_buf = netlbl_audit_start(AUDIT_MAC_CIPSOV4_ADD, audit_info); 518 if (audit_buf != NULL) { 519 const char *type_str; 520 switch (doi_type) { 521 case CIPSO_V4_MAP_TRANS: 522 type_str = "trans"; 523 break; 524 case CIPSO_V4_MAP_PASS: 525 type_str = "pass"; 526 break; 527 case CIPSO_V4_MAP_LOCAL: 528 type_str = "local"; 529 break; 530 default: 531 type_str = "(unknown)"; 532 } 533 audit_log_format(audit_buf, 534 " cipso_doi=%u cipso_type=%s res=%u", 535 doi, type_str, ret_val == 0 ? 1 : 0); 536 audit_log_end(audit_buf); 537 } 538 539 return ret_val; 540 } 541 542 /** 543 * cipso_v4_doi_free - Frees a DOI definition 544 * @entry: the entry's RCU field 545 * 546 * Description: 547 * This function frees all of the memory associated with a DOI definition. 548 * 549 */ 550 void cipso_v4_doi_free(struct cipso_v4_doi *doi_def) 551 { 552 if (doi_def == NULL) 553 return; 554 555 switch (doi_def->type) { 556 case CIPSO_V4_MAP_TRANS: 557 kfree(doi_def->map.std->lvl.cipso); 558 kfree(doi_def->map.std->lvl.local); 559 kfree(doi_def->map.std->cat.cipso); 560 kfree(doi_def->map.std->cat.local); 561 break; 562 } 563 kfree(doi_def); 564 } 565 566 /** 567 * cipso_v4_doi_free_rcu - Frees a DOI definition via the RCU pointer 568 * @entry: the entry's RCU field 569 * 570 * Description: 571 * This function is designed to be used as a callback to the call_rcu() 572 * function so that the memory allocated to the DOI definition can be released 573 * safely. 574 * 575 */ 576 static void cipso_v4_doi_free_rcu(struct rcu_head *entry) 577 { 578 struct cipso_v4_doi *doi_def; 579 580 doi_def = container_of(entry, struct cipso_v4_doi, rcu); 581 cipso_v4_doi_free(doi_def); 582 } 583 584 /** 585 * cipso_v4_doi_remove - Remove an existing DOI from the CIPSO protocol engine 586 * @doi: the DOI value 587 * @audit_secid: the LSM secid to use in the audit message 588 * 589 * Description: 590 * Removes a DOI definition from the CIPSO engine. The NetLabel routines will 591 * be called to release their own LSM domain mappings as well as our own 592 * domain list. Returns zero on success and negative values on failure. 593 * 594 */ 595 int cipso_v4_doi_remove(u32 doi, struct netlbl_audit *audit_info) 596 { 597 int ret_val; 598 struct cipso_v4_doi *doi_def; 599 struct audit_buffer *audit_buf; 600 601 spin_lock(&cipso_v4_doi_list_lock); 602 doi_def = cipso_v4_doi_search(doi); 603 if (doi_def == NULL) { 604 spin_unlock(&cipso_v4_doi_list_lock); 605 ret_val = -ENOENT; 606 goto doi_remove_return; 607 } 608 if (!atomic_dec_and_test(&doi_def->refcount)) { 609 spin_unlock(&cipso_v4_doi_list_lock); 610 ret_val = -EBUSY; 611 goto doi_remove_return; 612 } 613 list_del_rcu(&doi_def->list); 614 spin_unlock(&cipso_v4_doi_list_lock); 615 616 cipso_v4_cache_invalidate(); 617 call_rcu(&doi_def->rcu, cipso_v4_doi_free_rcu); 618 ret_val = 0; 619 620 doi_remove_return: 621 audit_buf = netlbl_audit_start(AUDIT_MAC_CIPSOV4_DEL, audit_info); 622 if (audit_buf != NULL) { 623 audit_log_format(audit_buf, 624 " cipso_doi=%u res=%u", 625 doi, ret_val == 0 ? 1 : 0); 626 audit_log_end(audit_buf); 627 } 628 629 return ret_val; 630 } 631 632 /** 633 * cipso_v4_doi_getdef - Returns a reference to a valid DOI definition 634 * @doi: the DOI value 635 * 636 * Description: 637 * Searches for a valid DOI definition and if one is found it is returned to 638 * the caller. Otherwise NULL is returned. The caller must ensure that 639 * rcu_read_lock() is held while accessing the returned definition and the DOI 640 * definition reference count is decremented when the caller is done. 641 * 642 */ 643 struct cipso_v4_doi *cipso_v4_doi_getdef(u32 doi) 644 { 645 struct cipso_v4_doi *doi_def; 646 647 rcu_read_lock(); 648 doi_def = cipso_v4_doi_search(doi); 649 if (doi_def == NULL) 650 goto doi_getdef_return; 651 if (!atomic_inc_not_zero(&doi_def->refcount)) 652 doi_def = NULL; 653 654 doi_getdef_return: 655 rcu_read_unlock(); 656 return doi_def; 657 } 658 659 /** 660 * cipso_v4_doi_putdef - Releases a reference for the given DOI definition 661 * @doi_def: the DOI definition 662 * 663 * Description: 664 * Releases a DOI definition reference obtained from cipso_v4_doi_getdef(). 665 * 666 */ 667 void cipso_v4_doi_putdef(struct cipso_v4_doi *doi_def) 668 { 669 if (doi_def == NULL) 670 return; 671 672 if (!atomic_dec_and_test(&doi_def->refcount)) 673 return; 674 spin_lock(&cipso_v4_doi_list_lock); 675 list_del_rcu(&doi_def->list); 676 spin_unlock(&cipso_v4_doi_list_lock); 677 678 cipso_v4_cache_invalidate(); 679 call_rcu(&doi_def->rcu, cipso_v4_doi_free_rcu); 680 } 681 682 /** 683 * cipso_v4_doi_walk - Iterate through the DOI definitions 684 * @skip_cnt: skip past this number of DOI definitions, updated 685 * @callback: callback for each DOI definition 686 * @cb_arg: argument for the callback function 687 * 688 * Description: 689 * Iterate over the DOI definition list, skipping the first @skip_cnt entries. 690 * For each entry call @callback, if @callback returns a negative value stop 691 * 'walking' through the list and return. Updates the value in @skip_cnt upon 692 * return. Returns zero on success, negative values on failure. 693 * 694 */ 695 int cipso_v4_doi_walk(u32 *skip_cnt, 696 int (*callback) (struct cipso_v4_doi *doi_def, void *arg), 697 void *cb_arg) 698 { 699 int ret_val = -ENOENT; 700 u32 doi_cnt = 0; 701 struct cipso_v4_doi *iter_doi; 702 703 rcu_read_lock(); 704 list_for_each_entry_rcu(iter_doi, &cipso_v4_doi_list, list) 705 if (atomic_read(&iter_doi->refcount) > 0) { 706 if (doi_cnt++ < *skip_cnt) 707 continue; 708 ret_val = callback(iter_doi, cb_arg); 709 if (ret_val < 0) { 710 doi_cnt--; 711 goto doi_walk_return; 712 } 713 } 714 715 doi_walk_return: 716 rcu_read_unlock(); 717 *skip_cnt = doi_cnt; 718 return ret_val; 719 } 720 721 /* 722 * Label Mapping Functions 723 */ 724 725 /** 726 * cipso_v4_map_lvl_valid - Checks to see if the given level is understood 727 * @doi_def: the DOI definition 728 * @level: the level to check 729 * 730 * Description: 731 * Checks the given level against the given DOI definition and returns a 732 * negative value if the level does not have a valid mapping and a zero value 733 * if the level is defined by the DOI. 734 * 735 */ 736 static int cipso_v4_map_lvl_valid(const struct cipso_v4_doi *doi_def, u8 level) 737 { 738 switch (doi_def->type) { 739 case CIPSO_V4_MAP_PASS: 740 return 0; 741 case CIPSO_V4_MAP_TRANS: 742 if (doi_def->map.std->lvl.cipso[level] < CIPSO_V4_INV_LVL) 743 return 0; 744 break; 745 } 746 747 return -EFAULT; 748 } 749 750 /** 751 * cipso_v4_map_lvl_hton - Perform a level mapping from the host to the network 752 * @doi_def: the DOI definition 753 * @host_lvl: the host MLS level 754 * @net_lvl: the network/CIPSO MLS level 755 * 756 * Description: 757 * Perform a label mapping to translate a local MLS level to the correct 758 * CIPSO level using the given DOI definition. Returns zero on success, 759 * negative values otherwise. 760 * 761 */ 762 static int cipso_v4_map_lvl_hton(const struct cipso_v4_doi *doi_def, 763 u32 host_lvl, 764 u32 *net_lvl) 765 { 766 switch (doi_def->type) { 767 case CIPSO_V4_MAP_PASS: 768 *net_lvl = host_lvl; 769 return 0; 770 case CIPSO_V4_MAP_TRANS: 771 if (host_lvl < doi_def->map.std->lvl.local_size && 772 doi_def->map.std->lvl.local[host_lvl] < CIPSO_V4_INV_LVL) { 773 *net_lvl = doi_def->map.std->lvl.local[host_lvl]; 774 return 0; 775 } 776 return -EPERM; 777 } 778 779 return -EINVAL; 780 } 781 782 /** 783 * cipso_v4_map_lvl_ntoh - Perform a level mapping from the network to the host 784 * @doi_def: the DOI definition 785 * @net_lvl: the network/CIPSO MLS level 786 * @host_lvl: the host MLS level 787 * 788 * Description: 789 * Perform a label mapping to translate a CIPSO level to the correct local MLS 790 * level using the given DOI definition. Returns zero on success, negative 791 * values otherwise. 792 * 793 */ 794 static int cipso_v4_map_lvl_ntoh(const struct cipso_v4_doi *doi_def, 795 u32 net_lvl, 796 u32 *host_lvl) 797 { 798 struct cipso_v4_std_map_tbl *map_tbl; 799 800 switch (doi_def->type) { 801 case CIPSO_V4_MAP_PASS: 802 *host_lvl = net_lvl; 803 return 0; 804 case CIPSO_V4_MAP_TRANS: 805 map_tbl = doi_def->map.std; 806 if (net_lvl < map_tbl->lvl.cipso_size && 807 map_tbl->lvl.cipso[net_lvl] < CIPSO_V4_INV_LVL) { 808 *host_lvl = doi_def->map.std->lvl.cipso[net_lvl]; 809 return 0; 810 } 811 return -EPERM; 812 } 813 814 return -EINVAL; 815 } 816 817 /** 818 * cipso_v4_map_cat_rbm_valid - Checks to see if the category bitmap is valid 819 * @doi_def: the DOI definition 820 * @bitmap: category bitmap 821 * @bitmap_len: bitmap length in bytes 822 * 823 * Description: 824 * Checks the given category bitmap against the given DOI definition and 825 * returns a negative value if any of the categories in the bitmap do not have 826 * a valid mapping and a zero value if all of the categories are valid. 827 * 828 */ 829 static int cipso_v4_map_cat_rbm_valid(const struct cipso_v4_doi *doi_def, 830 const unsigned char *bitmap, 831 u32 bitmap_len) 832 { 833 int cat = -1; 834 u32 bitmap_len_bits = bitmap_len * 8; 835 u32 cipso_cat_size; 836 u32 *cipso_array; 837 838 switch (doi_def->type) { 839 case CIPSO_V4_MAP_PASS: 840 return 0; 841 case CIPSO_V4_MAP_TRANS: 842 cipso_cat_size = doi_def->map.std->cat.cipso_size; 843 cipso_array = doi_def->map.std->cat.cipso; 844 for (;;) { 845 cat = cipso_v4_bitmap_walk(bitmap, 846 bitmap_len_bits, 847 cat + 1, 848 1); 849 if (cat < 0) 850 break; 851 if (cat >= cipso_cat_size || 852 cipso_array[cat] >= CIPSO_V4_INV_CAT) 853 return -EFAULT; 854 } 855 856 if (cat == -1) 857 return 0; 858 break; 859 } 860 861 return -EFAULT; 862 } 863 864 /** 865 * cipso_v4_map_cat_rbm_hton - Perform a category mapping from host to network 866 * @doi_def: the DOI definition 867 * @secattr: the security attributes 868 * @net_cat: the zero'd out category bitmap in network/CIPSO format 869 * @net_cat_len: the length of the CIPSO bitmap in bytes 870 * 871 * Description: 872 * Perform a label mapping to translate a local MLS category bitmap to the 873 * correct CIPSO bitmap using the given DOI definition. Returns the minimum 874 * size in bytes of the network bitmap on success, negative values otherwise. 875 * 876 */ 877 static int cipso_v4_map_cat_rbm_hton(const struct cipso_v4_doi *doi_def, 878 const struct netlbl_lsm_secattr *secattr, 879 unsigned char *net_cat, 880 u32 net_cat_len) 881 { 882 int host_spot = -1; 883 u32 net_spot = CIPSO_V4_INV_CAT; 884 u32 net_spot_max = 0; 885 u32 net_clen_bits = net_cat_len * 8; 886 u32 host_cat_size = 0; 887 u32 *host_cat_array = NULL; 888 889 if (doi_def->type == CIPSO_V4_MAP_TRANS) { 890 host_cat_size = doi_def->map.std->cat.local_size; 891 host_cat_array = doi_def->map.std->cat.local; 892 } 893 894 for (;;) { 895 host_spot = netlbl_secattr_catmap_walk(secattr->attr.mls.cat, 896 host_spot + 1); 897 if (host_spot < 0) 898 break; 899 900 switch (doi_def->type) { 901 case CIPSO_V4_MAP_PASS: 902 net_spot = host_spot; 903 break; 904 case CIPSO_V4_MAP_TRANS: 905 if (host_spot >= host_cat_size) 906 return -EPERM; 907 net_spot = host_cat_array[host_spot]; 908 if (net_spot >= CIPSO_V4_INV_CAT) 909 return -EPERM; 910 break; 911 } 912 if (net_spot >= net_clen_bits) 913 return -ENOSPC; 914 cipso_v4_bitmap_setbit(net_cat, net_spot, 1); 915 916 if (net_spot > net_spot_max) 917 net_spot_max = net_spot; 918 } 919 920 if (++net_spot_max % 8) 921 return net_spot_max / 8 + 1; 922 return net_spot_max / 8; 923 } 924 925 /** 926 * cipso_v4_map_cat_rbm_ntoh - Perform a category mapping from network to host 927 * @doi_def: the DOI definition 928 * @net_cat: the category bitmap in network/CIPSO format 929 * @net_cat_len: the length of the CIPSO bitmap in bytes 930 * @secattr: the security attributes 931 * 932 * Description: 933 * Perform a label mapping to translate a CIPSO bitmap to the correct local 934 * MLS category bitmap using the given DOI definition. Returns zero on 935 * success, negative values on failure. 936 * 937 */ 938 static int cipso_v4_map_cat_rbm_ntoh(const struct cipso_v4_doi *doi_def, 939 const unsigned char *net_cat, 940 u32 net_cat_len, 941 struct netlbl_lsm_secattr *secattr) 942 { 943 int ret_val; 944 int net_spot = -1; 945 u32 host_spot = CIPSO_V4_INV_CAT; 946 u32 net_clen_bits = net_cat_len * 8; 947 u32 net_cat_size = 0; 948 u32 *net_cat_array = NULL; 949 950 if (doi_def->type == CIPSO_V4_MAP_TRANS) { 951 net_cat_size = doi_def->map.std->cat.cipso_size; 952 net_cat_array = doi_def->map.std->cat.cipso; 953 } 954 955 for (;;) { 956 net_spot = cipso_v4_bitmap_walk(net_cat, 957 net_clen_bits, 958 net_spot + 1, 959 1); 960 if (net_spot < 0) { 961 if (net_spot == -2) 962 return -EFAULT; 963 return 0; 964 } 965 966 switch (doi_def->type) { 967 case CIPSO_V4_MAP_PASS: 968 host_spot = net_spot; 969 break; 970 case CIPSO_V4_MAP_TRANS: 971 if (net_spot >= net_cat_size) 972 return -EPERM; 973 host_spot = net_cat_array[net_spot]; 974 if (host_spot >= CIPSO_V4_INV_CAT) 975 return -EPERM; 976 break; 977 } 978 ret_val = netlbl_secattr_catmap_setbit(secattr->attr.mls.cat, 979 host_spot, 980 GFP_ATOMIC); 981 if (ret_val != 0) 982 return ret_val; 983 } 984 985 return -EINVAL; 986 } 987 988 /** 989 * cipso_v4_map_cat_enum_valid - Checks to see if the categories are valid 990 * @doi_def: the DOI definition 991 * @enumcat: category list 992 * @enumcat_len: length of the category list in bytes 993 * 994 * Description: 995 * Checks the given categories against the given DOI definition and returns a 996 * negative value if any of the categories do not have a valid mapping and a 997 * zero value if all of the categories are valid. 998 * 999 */ 1000 static int cipso_v4_map_cat_enum_valid(const struct cipso_v4_doi *doi_def, 1001 const unsigned char *enumcat, 1002 u32 enumcat_len) 1003 { 1004 u16 cat; 1005 int cat_prev = -1; 1006 u32 iter; 1007 1008 if (doi_def->type != CIPSO_V4_MAP_PASS || enumcat_len & 0x01) 1009 return -EFAULT; 1010 1011 for (iter = 0; iter < enumcat_len; iter += 2) { 1012 cat = get_unaligned_be16(&enumcat[iter]); 1013 if (cat <= cat_prev) 1014 return -EFAULT; 1015 cat_prev = cat; 1016 } 1017 1018 return 0; 1019 } 1020 1021 /** 1022 * cipso_v4_map_cat_enum_hton - Perform a category mapping from host to network 1023 * @doi_def: the DOI definition 1024 * @secattr: the security attributes 1025 * @net_cat: the zero'd out category list in network/CIPSO format 1026 * @net_cat_len: the length of the CIPSO category list in bytes 1027 * 1028 * Description: 1029 * Perform a label mapping to translate a local MLS category bitmap to the 1030 * correct CIPSO category list using the given DOI definition. Returns the 1031 * size in bytes of the network category bitmap on success, negative values 1032 * otherwise. 1033 * 1034 */ 1035 static int cipso_v4_map_cat_enum_hton(const struct cipso_v4_doi *doi_def, 1036 const struct netlbl_lsm_secattr *secattr, 1037 unsigned char *net_cat, 1038 u32 net_cat_len) 1039 { 1040 int cat = -1; 1041 u32 cat_iter = 0; 1042 1043 for (;;) { 1044 cat = netlbl_secattr_catmap_walk(secattr->attr.mls.cat, 1045 cat + 1); 1046 if (cat < 0) 1047 break; 1048 if ((cat_iter + 2) > net_cat_len) 1049 return -ENOSPC; 1050 1051 *((__be16 *)&net_cat[cat_iter]) = htons(cat); 1052 cat_iter += 2; 1053 } 1054 1055 return cat_iter; 1056 } 1057 1058 /** 1059 * cipso_v4_map_cat_enum_ntoh - Perform a category mapping from network to host 1060 * @doi_def: the DOI definition 1061 * @net_cat: the category list in network/CIPSO format 1062 * @net_cat_len: the length of the CIPSO bitmap in bytes 1063 * @secattr: the security attributes 1064 * 1065 * Description: 1066 * Perform a label mapping to translate a CIPSO category list to the correct 1067 * local MLS category bitmap using the given DOI definition. Returns zero on 1068 * success, negative values on failure. 1069 * 1070 */ 1071 static int cipso_v4_map_cat_enum_ntoh(const struct cipso_v4_doi *doi_def, 1072 const unsigned char *net_cat, 1073 u32 net_cat_len, 1074 struct netlbl_lsm_secattr *secattr) 1075 { 1076 int ret_val; 1077 u32 iter; 1078 1079 for (iter = 0; iter < net_cat_len; iter += 2) { 1080 ret_val = netlbl_secattr_catmap_setbit(secattr->attr.mls.cat, 1081 get_unaligned_be16(&net_cat[iter]), 1082 GFP_ATOMIC); 1083 if (ret_val != 0) 1084 return ret_val; 1085 } 1086 1087 return 0; 1088 } 1089 1090 /** 1091 * cipso_v4_map_cat_rng_valid - Checks to see if the categories are valid 1092 * @doi_def: the DOI definition 1093 * @rngcat: category list 1094 * @rngcat_len: length of the category list in bytes 1095 * 1096 * Description: 1097 * Checks the given categories against the given DOI definition and returns a 1098 * negative value if any of the categories do not have a valid mapping and a 1099 * zero value if all of the categories are valid. 1100 * 1101 */ 1102 static int cipso_v4_map_cat_rng_valid(const struct cipso_v4_doi *doi_def, 1103 const unsigned char *rngcat, 1104 u32 rngcat_len) 1105 { 1106 u16 cat_high; 1107 u16 cat_low; 1108 u32 cat_prev = CIPSO_V4_MAX_REM_CATS + 1; 1109 u32 iter; 1110 1111 if (doi_def->type != CIPSO_V4_MAP_PASS || rngcat_len & 0x01) 1112 return -EFAULT; 1113 1114 for (iter = 0; iter < rngcat_len; iter += 4) { 1115 cat_high = get_unaligned_be16(&rngcat[iter]); 1116 if ((iter + 4) <= rngcat_len) 1117 cat_low = get_unaligned_be16(&rngcat[iter + 2]); 1118 else 1119 cat_low = 0; 1120 1121 if (cat_high > cat_prev) 1122 return -EFAULT; 1123 1124 cat_prev = cat_low; 1125 } 1126 1127 return 0; 1128 } 1129 1130 /** 1131 * cipso_v4_map_cat_rng_hton - Perform a category mapping from host to network 1132 * @doi_def: the DOI definition 1133 * @secattr: the security attributes 1134 * @net_cat: the zero'd out category list in network/CIPSO format 1135 * @net_cat_len: the length of the CIPSO category list in bytes 1136 * 1137 * Description: 1138 * Perform a label mapping to translate a local MLS category bitmap to the 1139 * correct CIPSO category list using the given DOI definition. Returns the 1140 * size in bytes of the network category bitmap on success, negative values 1141 * otherwise. 1142 * 1143 */ 1144 static int cipso_v4_map_cat_rng_hton(const struct cipso_v4_doi *doi_def, 1145 const struct netlbl_lsm_secattr *secattr, 1146 unsigned char *net_cat, 1147 u32 net_cat_len) 1148 { 1149 int iter = -1; 1150 u16 array[CIPSO_V4_TAG_RNG_CAT_MAX * 2]; 1151 u32 array_cnt = 0; 1152 u32 cat_size = 0; 1153 1154 /* make sure we don't overflow the 'array[]' variable */ 1155 if (net_cat_len > 1156 (CIPSO_V4_OPT_LEN_MAX - CIPSO_V4_HDR_LEN - CIPSO_V4_TAG_RNG_BLEN)) 1157 return -ENOSPC; 1158 1159 for (;;) { 1160 iter = netlbl_secattr_catmap_walk(secattr->attr.mls.cat, 1161 iter + 1); 1162 if (iter < 0) 1163 break; 1164 cat_size += (iter == 0 ? 0 : sizeof(u16)); 1165 if (cat_size > net_cat_len) 1166 return -ENOSPC; 1167 array[array_cnt++] = iter; 1168 1169 iter = netlbl_secattr_catmap_walk_rng(secattr->attr.mls.cat, 1170 iter); 1171 if (iter < 0) 1172 return -EFAULT; 1173 cat_size += sizeof(u16); 1174 if (cat_size > net_cat_len) 1175 return -ENOSPC; 1176 array[array_cnt++] = iter; 1177 } 1178 1179 for (iter = 0; array_cnt > 0;) { 1180 *((__be16 *)&net_cat[iter]) = htons(array[--array_cnt]); 1181 iter += 2; 1182 array_cnt--; 1183 if (array[array_cnt] != 0) { 1184 *((__be16 *)&net_cat[iter]) = htons(array[array_cnt]); 1185 iter += 2; 1186 } 1187 } 1188 1189 return cat_size; 1190 } 1191 1192 /** 1193 * cipso_v4_map_cat_rng_ntoh - Perform a category mapping from network to host 1194 * @doi_def: the DOI definition 1195 * @net_cat: the category list in network/CIPSO format 1196 * @net_cat_len: the length of the CIPSO bitmap in bytes 1197 * @secattr: the security attributes 1198 * 1199 * Description: 1200 * Perform a label mapping to translate a CIPSO category list to the correct 1201 * local MLS category bitmap using the given DOI definition. Returns zero on 1202 * success, negative values on failure. 1203 * 1204 */ 1205 static int cipso_v4_map_cat_rng_ntoh(const struct cipso_v4_doi *doi_def, 1206 const unsigned char *net_cat, 1207 u32 net_cat_len, 1208 struct netlbl_lsm_secattr *secattr) 1209 { 1210 int ret_val; 1211 u32 net_iter; 1212 u16 cat_low; 1213 u16 cat_high; 1214 1215 for (net_iter = 0; net_iter < net_cat_len; net_iter += 4) { 1216 cat_high = get_unaligned_be16(&net_cat[net_iter]); 1217 if ((net_iter + 4) <= net_cat_len) 1218 cat_low = get_unaligned_be16(&net_cat[net_iter + 2]); 1219 else 1220 cat_low = 0; 1221 1222 ret_val = netlbl_secattr_catmap_setrng(secattr->attr.mls.cat, 1223 cat_low, 1224 cat_high, 1225 GFP_ATOMIC); 1226 if (ret_val != 0) 1227 return ret_val; 1228 } 1229 1230 return 0; 1231 } 1232 1233 /* 1234 * Protocol Handling Functions 1235 */ 1236 1237 /** 1238 * cipso_v4_gentag_hdr - Generate a CIPSO option header 1239 * @doi_def: the DOI definition 1240 * @len: the total tag length in bytes, not including this header 1241 * @buf: the CIPSO option buffer 1242 * 1243 * Description: 1244 * Write a CIPSO header into the beginning of @buffer. 1245 * 1246 */ 1247 static void cipso_v4_gentag_hdr(const struct cipso_v4_doi *doi_def, 1248 unsigned char *buf, 1249 u32 len) 1250 { 1251 buf[0] = IPOPT_CIPSO; 1252 buf[1] = CIPSO_V4_HDR_LEN + len; 1253 *(__be32 *)&buf[2] = htonl(doi_def->doi); 1254 } 1255 1256 /** 1257 * cipso_v4_gentag_rbm - Generate a CIPSO restricted bitmap tag (type #1) 1258 * @doi_def: the DOI definition 1259 * @secattr: the security attributes 1260 * @buffer: the option buffer 1261 * @buffer_len: length of buffer in bytes 1262 * 1263 * Description: 1264 * Generate a CIPSO option using the restricted bitmap tag, tag type #1. The 1265 * actual buffer length may be larger than the indicated size due to 1266 * translation between host and network category bitmaps. Returns the size of 1267 * the tag on success, negative values on failure. 1268 * 1269 */ 1270 static int cipso_v4_gentag_rbm(const struct cipso_v4_doi *doi_def, 1271 const struct netlbl_lsm_secattr *secattr, 1272 unsigned char *buffer, 1273 u32 buffer_len) 1274 { 1275 int ret_val; 1276 u32 tag_len; 1277 u32 level; 1278 1279 if ((secattr->flags & NETLBL_SECATTR_MLS_LVL) == 0) 1280 return -EPERM; 1281 1282 ret_val = cipso_v4_map_lvl_hton(doi_def, 1283 secattr->attr.mls.lvl, 1284 &level); 1285 if (ret_val != 0) 1286 return ret_val; 1287 1288 if (secattr->flags & NETLBL_SECATTR_MLS_CAT) { 1289 ret_val = cipso_v4_map_cat_rbm_hton(doi_def, 1290 secattr, 1291 &buffer[4], 1292 buffer_len - 4); 1293 if (ret_val < 0) 1294 return ret_val; 1295 1296 /* This will send packets using the "optimized" format when 1297 * possibile as specified in section 3.4.2.6 of the 1298 * CIPSO draft. */ 1299 if (cipso_v4_rbm_optfmt && ret_val > 0 && ret_val <= 10) 1300 tag_len = 14; 1301 else 1302 tag_len = 4 + ret_val; 1303 } else 1304 tag_len = 4; 1305 1306 buffer[0] = CIPSO_V4_TAG_RBITMAP; 1307 buffer[1] = tag_len; 1308 buffer[3] = level; 1309 1310 return tag_len; 1311 } 1312 1313 /** 1314 * cipso_v4_parsetag_rbm - Parse a CIPSO restricted bitmap tag 1315 * @doi_def: the DOI definition 1316 * @tag: the CIPSO tag 1317 * @secattr: the security attributes 1318 * 1319 * Description: 1320 * Parse a CIPSO restricted bitmap tag (tag type #1) and return the security 1321 * attributes in @secattr. Return zero on success, negatives values on 1322 * failure. 1323 * 1324 */ 1325 static int cipso_v4_parsetag_rbm(const struct cipso_v4_doi *doi_def, 1326 const unsigned char *tag, 1327 struct netlbl_lsm_secattr *secattr) 1328 { 1329 int ret_val; 1330 u8 tag_len = tag[1]; 1331 u32 level; 1332 1333 ret_val = cipso_v4_map_lvl_ntoh(doi_def, tag[3], &level); 1334 if (ret_val != 0) 1335 return ret_val; 1336 secattr->attr.mls.lvl = level; 1337 secattr->flags |= NETLBL_SECATTR_MLS_LVL; 1338 1339 if (tag_len > 4) { 1340 secattr->attr.mls.cat = 1341 netlbl_secattr_catmap_alloc(GFP_ATOMIC); 1342 if (secattr->attr.mls.cat == NULL) 1343 return -ENOMEM; 1344 1345 ret_val = cipso_v4_map_cat_rbm_ntoh(doi_def, 1346 &tag[4], 1347 tag_len - 4, 1348 secattr); 1349 if (ret_val != 0) { 1350 netlbl_secattr_catmap_free(secattr->attr.mls.cat); 1351 return ret_val; 1352 } 1353 1354 secattr->flags |= NETLBL_SECATTR_MLS_CAT; 1355 } 1356 1357 return 0; 1358 } 1359 1360 /** 1361 * cipso_v4_gentag_enum - Generate a CIPSO enumerated tag (type #2) 1362 * @doi_def: the DOI definition 1363 * @secattr: the security attributes 1364 * @buffer: the option buffer 1365 * @buffer_len: length of buffer in bytes 1366 * 1367 * Description: 1368 * Generate a CIPSO option using the enumerated tag, tag type #2. Returns the 1369 * size of the tag on success, negative values on failure. 1370 * 1371 */ 1372 static int cipso_v4_gentag_enum(const struct cipso_v4_doi *doi_def, 1373 const struct netlbl_lsm_secattr *secattr, 1374 unsigned char *buffer, 1375 u32 buffer_len) 1376 { 1377 int ret_val; 1378 u32 tag_len; 1379 u32 level; 1380 1381 if (!(secattr->flags & NETLBL_SECATTR_MLS_LVL)) 1382 return -EPERM; 1383 1384 ret_val = cipso_v4_map_lvl_hton(doi_def, 1385 secattr->attr.mls.lvl, 1386 &level); 1387 if (ret_val != 0) 1388 return ret_val; 1389 1390 if (secattr->flags & NETLBL_SECATTR_MLS_CAT) { 1391 ret_val = cipso_v4_map_cat_enum_hton(doi_def, 1392 secattr, 1393 &buffer[4], 1394 buffer_len - 4); 1395 if (ret_val < 0) 1396 return ret_val; 1397 1398 tag_len = 4 + ret_val; 1399 } else 1400 tag_len = 4; 1401 1402 buffer[0] = CIPSO_V4_TAG_ENUM; 1403 buffer[1] = tag_len; 1404 buffer[3] = level; 1405 1406 return tag_len; 1407 } 1408 1409 /** 1410 * cipso_v4_parsetag_enum - Parse a CIPSO enumerated tag 1411 * @doi_def: the DOI definition 1412 * @tag: the CIPSO tag 1413 * @secattr: the security attributes 1414 * 1415 * Description: 1416 * Parse a CIPSO enumerated tag (tag type #2) and return the security 1417 * attributes in @secattr. Return zero on success, negatives values on 1418 * failure. 1419 * 1420 */ 1421 static int cipso_v4_parsetag_enum(const struct cipso_v4_doi *doi_def, 1422 const unsigned char *tag, 1423 struct netlbl_lsm_secattr *secattr) 1424 { 1425 int ret_val; 1426 u8 tag_len = tag[1]; 1427 u32 level; 1428 1429 ret_val = cipso_v4_map_lvl_ntoh(doi_def, tag[3], &level); 1430 if (ret_val != 0) 1431 return ret_val; 1432 secattr->attr.mls.lvl = level; 1433 secattr->flags |= NETLBL_SECATTR_MLS_LVL; 1434 1435 if (tag_len > 4) { 1436 secattr->attr.mls.cat = 1437 netlbl_secattr_catmap_alloc(GFP_ATOMIC); 1438 if (secattr->attr.mls.cat == NULL) 1439 return -ENOMEM; 1440 1441 ret_val = cipso_v4_map_cat_enum_ntoh(doi_def, 1442 &tag[4], 1443 tag_len - 4, 1444 secattr); 1445 if (ret_val != 0) { 1446 netlbl_secattr_catmap_free(secattr->attr.mls.cat); 1447 return ret_val; 1448 } 1449 1450 secattr->flags |= NETLBL_SECATTR_MLS_CAT; 1451 } 1452 1453 return 0; 1454 } 1455 1456 /** 1457 * cipso_v4_gentag_rng - Generate a CIPSO ranged tag (type #5) 1458 * @doi_def: the DOI definition 1459 * @secattr: the security attributes 1460 * @buffer: the option buffer 1461 * @buffer_len: length of buffer in bytes 1462 * 1463 * Description: 1464 * Generate a CIPSO option using the ranged tag, tag type #5. Returns the 1465 * size of the tag on success, negative values on failure. 1466 * 1467 */ 1468 static int cipso_v4_gentag_rng(const struct cipso_v4_doi *doi_def, 1469 const struct netlbl_lsm_secattr *secattr, 1470 unsigned char *buffer, 1471 u32 buffer_len) 1472 { 1473 int ret_val; 1474 u32 tag_len; 1475 u32 level; 1476 1477 if (!(secattr->flags & NETLBL_SECATTR_MLS_LVL)) 1478 return -EPERM; 1479 1480 ret_val = cipso_v4_map_lvl_hton(doi_def, 1481 secattr->attr.mls.lvl, 1482 &level); 1483 if (ret_val != 0) 1484 return ret_val; 1485 1486 if (secattr->flags & NETLBL_SECATTR_MLS_CAT) { 1487 ret_val = cipso_v4_map_cat_rng_hton(doi_def, 1488 secattr, 1489 &buffer[4], 1490 buffer_len - 4); 1491 if (ret_val < 0) 1492 return ret_val; 1493 1494 tag_len = 4 + ret_val; 1495 } else 1496 tag_len = 4; 1497 1498 buffer[0] = CIPSO_V4_TAG_RANGE; 1499 buffer[1] = tag_len; 1500 buffer[3] = level; 1501 1502 return tag_len; 1503 } 1504 1505 /** 1506 * cipso_v4_parsetag_rng - Parse a CIPSO ranged tag 1507 * @doi_def: the DOI definition 1508 * @tag: the CIPSO tag 1509 * @secattr: the security attributes 1510 * 1511 * Description: 1512 * Parse a CIPSO ranged tag (tag type #5) and return the security attributes 1513 * in @secattr. Return zero on success, negatives values on failure. 1514 * 1515 */ 1516 static int cipso_v4_parsetag_rng(const struct cipso_v4_doi *doi_def, 1517 const unsigned char *tag, 1518 struct netlbl_lsm_secattr *secattr) 1519 { 1520 int ret_val; 1521 u8 tag_len = tag[1]; 1522 u32 level; 1523 1524 ret_val = cipso_v4_map_lvl_ntoh(doi_def, tag[3], &level); 1525 if (ret_val != 0) 1526 return ret_val; 1527 secattr->attr.mls.lvl = level; 1528 secattr->flags |= NETLBL_SECATTR_MLS_LVL; 1529 1530 if (tag_len > 4) { 1531 secattr->attr.mls.cat = 1532 netlbl_secattr_catmap_alloc(GFP_ATOMIC); 1533 if (secattr->attr.mls.cat == NULL) 1534 return -ENOMEM; 1535 1536 ret_val = cipso_v4_map_cat_rng_ntoh(doi_def, 1537 &tag[4], 1538 tag_len - 4, 1539 secattr); 1540 if (ret_val != 0) { 1541 netlbl_secattr_catmap_free(secattr->attr.mls.cat); 1542 return ret_val; 1543 } 1544 1545 secattr->flags |= NETLBL_SECATTR_MLS_CAT; 1546 } 1547 1548 return 0; 1549 } 1550 1551 /** 1552 * cipso_v4_gentag_loc - Generate a CIPSO local tag (non-standard) 1553 * @doi_def: the DOI definition 1554 * @secattr: the security attributes 1555 * @buffer: the option buffer 1556 * @buffer_len: length of buffer in bytes 1557 * 1558 * Description: 1559 * Generate a CIPSO option using the local tag. Returns the size of the tag 1560 * on success, negative values on failure. 1561 * 1562 */ 1563 static int cipso_v4_gentag_loc(const struct cipso_v4_doi *doi_def, 1564 const struct netlbl_lsm_secattr *secattr, 1565 unsigned char *buffer, 1566 u32 buffer_len) 1567 { 1568 if (!(secattr->flags & NETLBL_SECATTR_SECID)) 1569 return -EPERM; 1570 1571 buffer[0] = CIPSO_V4_TAG_LOCAL; 1572 buffer[1] = CIPSO_V4_TAG_LOC_BLEN; 1573 *(u32 *)&buffer[2] = secattr->attr.secid; 1574 1575 return CIPSO_V4_TAG_LOC_BLEN; 1576 } 1577 1578 /** 1579 * cipso_v4_parsetag_loc - Parse a CIPSO local tag 1580 * @doi_def: the DOI definition 1581 * @tag: the CIPSO tag 1582 * @secattr: the security attributes 1583 * 1584 * Description: 1585 * Parse a CIPSO local tag and return the security attributes in @secattr. 1586 * Return zero on success, negatives values on failure. 1587 * 1588 */ 1589 static int cipso_v4_parsetag_loc(const struct cipso_v4_doi *doi_def, 1590 const unsigned char *tag, 1591 struct netlbl_lsm_secattr *secattr) 1592 { 1593 secattr->attr.secid = *(u32 *)&tag[2]; 1594 secattr->flags |= NETLBL_SECATTR_SECID; 1595 1596 return 0; 1597 } 1598 1599 /** 1600 * cipso_v4_validate - Validate a CIPSO option 1601 * @option: the start of the option, on error it is set to point to the error 1602 * 1603 * Description: 1604 * This routine is called to validate a CIPSO option, it checks all of the 1605 * fields to ensure that they are at least valid, see the draft snippet below 1606 * for details. If the option is valid then a zero value is returned and 1607 * the value of @option is unchanged. If the option is invalid then a 1608 * non-zero value is returned and @option is adjusted to point to the 1609 * offending portion of the option. From the IETF draft ... 1610 * 1611 * "If any field within the CIPSO options, such as the DOI identifier, is not 1612 * recognized the IP datagram is discarded and an ICMP 'parameter problem' 1613 * (type 12) is generated and returned. The ICMP code field is set to 'bad 1614 * parameter' (code 0) and the pointer is set to the start of the CIPSO field 1615 * that is unrecognized." 1616 * 1617 */ 1618 int cipso_v4_validate(const struct sk_buff *skb, unsigned char **option) 1619 { 1620 unsigned char *opt = *option; 1621 unsigned char *tag; 1622 unsigned char opt_iter; 1623 unsigned char err_offset = 0; 1624 u8 opt_len; 1625 u8 tag_len; 1626 struct cipso_v4_doi *doi_def = NULL; 1627 u32 tag_iter; 1628 1629 /* caller already checks for length values that are too large */ 1630 opt_len = opt[1]; 1631 if (opt_len < 8) { 1632 err_offset = 1; 1633 goto validate_return; 1634 } 1635 1636 rcu_read_lock(); 1637 doi_def = cipso_v4_doi_search(get_unaligned_be32(&opt[2])); 1638 if (doi_def == NULL) { 1639 err_offset = 2; 1640 goto validate_return_locked; 1641 } 1642 1643 opt_iter = CIPSO_V4_HDR_LEN; 1644 tag = opt + opt_iter; 1645 while (opt_iter < opt_len) { 1646 for (tag_iter = 0; doi_def->tags[tag_iter] != tag[0];) 1647 if (doi_def->tags[tag_iter] == CIPSO_V4_TAG_INVALID || 1648 ++tag_iter == CIPSO_V4_TAG_MAXCNT) { 1649 err_offset = opt_iter; 1650 goto validate_return_locked; 1651 } 1652 1653 tag_len = tag[1]; 1654 if (tag_len > (opt_len - opt_iter)) { 1655 err_offset = opt_iter + 1; 1656 goto validate_return_locked; 1657 } 1658 1659 switch (tag[0]) { 1660 case CIPSO_V4_TAG_RBITMAP: 1661 if (tag_len < CIPSO_V4_TAG_RBM_BLEN) { 1662 err_offset = opt_iter + 1; 1663 goto validate_return_locked; 1664 } 1665 1666 /* We are already going to do all the verification 1667 * necessary at the socket layer so from our point of 1668 * view it is safe to turn these checks off (and less 1669 * work), however, the CIPSO draft says we should do 1670 * all the CIPSO validations here but it doesn't 1671 * really specify _exactly_ what we need to validate 1672 * ... so, just make it a sysctl tunable. */ 1673 if (cipso_v4_rbm_strictvalid) { 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_RBM_BLEN && 1680 cipso_v4_map_cat_rbm_valid(doi_def, 1681 &tag[4], 1682 tag_len - 4) < 0) { 1683 err_offset = opt_iter + 4; 1684 goto validate_return_locked; 1685 } 1686 } 1687 break; 1688 case CIPSO_V4_TAG_ENUM: 1689 if (tag_len < CIPSO_V4_TAG_ENUM_BLEN) { 1690 err_offset = opt_iter + 1; 1691 goto validate_return_locked; 1692 } 1693 1694 if (cipso_v4_map_lvl_valid(doi_def, 1695 tag[3]) < 0) { 1696 err_offset = opt_iter + 3; 1697 goto validate_return_locked; 1698 } 1699 if (tag_len > CIPSO_V4_TAG_ENUM_BLEN && 1700 cipso_v4_map_cat_enum_valid(doi_def, 1701 &tag[4], 1702 tag_len - 4) < 0) { 1703 err_offset = opt_iter + 4; 1704 goto validate_return_locked; 1705 } 1706 break; 1707 case CIPSO_V4_TAG_RANGE: 1708 if (tag_len < CIPSO_V4_TAG_RNG_BLEN) { 1709 err_offset = opt_iter + 1; 1710 goto validate_return_locked; 1711 } 1712 1713 if (cipso_v4_map_lvl_valid(doi_def, 1714 tag[3]) < 0) { 1715 err_offset = opt_iter + 3; 1716 goto validate_return_locked; 1717 } 1718 if (tag_len > CIPSO_V4_TAG_RNG_BLEN && 1719 cipso_v4_map_cat_rng_valid(doi_def, 1720 &tag[4], 1721 tag_len - 4) < 0) { 1722 err_offset = opt_iter + 4; 1723 goto validate_return_locked; 1724 } 1725 break; 1726 case CIPSO_V4_TAG_LOCAL: 1727 /* This is a non-standard tag that we only allow for 1728 * local connections, so if the incoming interface is 1729 * not the loopback device drop the packet. */ 1730 if (!(skb->dev->flags & IFF_LOOPBACK)) { 1731 err_offset = opt_iter; 1732 goto validate_return_locked; 1733 } 1734 if (tag_len != CIPSO_V4_TAG_LOC_BLEN) { 1735 err_offset = opt_iter + 1; 1736 goto validate_return_locked; 1737 } 1738 break; 1739 default: 1740 err_offset = opt_iter; 1741 goto validate_return_locked; 1742 } 1743 1744 tag += tag_len; 1745 opt_iter += tag_len; 1746 } 1747 1748 validate_return_locked: 1749 rcu_read_unlock(); 1750 validate_return: 1751 *option = opt + err_offset; 1752 return err_offset; 1753 } 1754 1755 /** 1756 * cipso_v4_error - Send the correct reponse for a bad packet 1757 * @skb: the packet 1758 * @error: the error code 1759 * @gateway: CIPSO gateway flag 1760 * 1761 * Description: 1762 * Based on the error code given in @error, send an ICMP error message back to 1763 * the originating host. From the IETF draft ... 1764 * 1765 * "If the contents of the CIPSO [option] are valid but the security label is 1766 * outside of the configured host or port label range, the datagram is 1767 * discarded and an ICMP 'destination unreachable' (type 3) is generated and 1768 * returned. The code field of the ICMP is set to 'communication with 1769 * destination network administratively prohibited' (code 9) or to 1770 * 'communication with destination host administratively prohibited' 1771 * (code 10). The value of the code is dependent on whether the originator 1772 * of the ICMP message is acting as a CIPSO host or a CIPSO gateway. The 1773 * recipient of the ICMP message MUST be able to handle either value. The 1774 * same procedure is performed if a CIPSO [option] can not be added to an 1775 * IP packet because it is too large to fit in the IP options area." 1776 * 1777 * "If the error is triggered by receipt of an ICMP message, the message is 1778 * discarded and no response is permitted (consistent with general ICMP 1779 * processing rules)." 1780 * 1781 */ 1782 void cipso_v4_error(struct sk_buff *skb, int error, u32 gateway) 1783 { 1784 if (ip_hdr(skb)->protocol == IPPROTO_ICMP || error != -EACCES) 1785 return; 1786 1787 if (gateway) 1788 icmp_send(skb, ICMP_DEST_UNREACH, ICMP_NET_ANO, 0); 1789 else 1790 icmp_send(skb, ICMP_DEST_UNREACH, ICMP_HOST_ANO, 0); 1791 } 1792 1793 /** 1794 * cipso_v4_genopt - Generate a CIPSO option 1795 * @buf: the option buffer 1796 * @buf_len: the size of opt_buf 1797 * @doi_def: the CIPSO DOI to use 1798 * @secattr: the security attributes 1799 * 1800 * Description: 1801 * Generate a CIPSO option using the DOI definition and security attributes 1802 * passed to the function. Returns the length of the option on success and 1803 * negative values on failure. 1804 * 1805 */ 1806 static int cipso_v4_genopt(unsigned char *buf, u32 buf_len, 1807 const struct cipso_v4_doi *doi_def, 1808 const struct netlbl_lsm_secattr *secattr) 1809 { 1810 int ret_val; 1811 u32 iter; 1812 1813 if (buf_len <= CIPSO_V4_HDR_LEN) 1814 return -ENOSPC; 1815 1816 /* XXX - This code assumes only one tag per CIPSO option which isn't 1817 * really a good assumption to make but since we only support the MAC 1818 * tags right now it is a safe assumption. */ 1819 iter = 0; 1820 do { 1821 memset(buf, 0, buf_len); 1822 switch (doi_def->tags[iter]) { 1823 case CIPSO_V4_TAG_RBITMAP: 1824 ret_val = cipso_v4_gentag_rbm(doi_def, 1825 secattr, 1826 &buf[CIPSO_V4_HDR_LEN], 1827 buf_len - CIPSO_V4_HDR_LEN); 1828 break; 1829 case CIPSO_V4_TAG_ENUM: 1830 ret_val = cipso_v4_gentag_enum(doi_def, 1831 secattr, 1832 &buf[CIPSO_V4_HDR_LEN], 1833 buf_len - CIPSO_V4_HDR_LEN); 1834 break; 1835 case CIPSO_V4_TAG_RANGE: 1836 ret_val = cipso_v4_gentag_rng(doi_def, 1837 secattr, 1838 &buf[CIPSO_V4_HDR_LEN], 1839 buf_len - CIPSO_V4_HDR_LEN); 1840 break; 1841 case CIPSO_V4_TAG_LOCAL: 1842 ret_val = cipso_v4_gentag_loc(doi_def, 1843 secattr, 1844 &buf[CIPSO_V4_HDR_LEN], 1845 buf_len - CIPSO_V4_HDR_LEN); 1846 break; 1847 default: 1848 return -EPERM; 1849 } 1850 1851 iter++; 1852 } while (ret_val < 0 && 1853 iter < CIPSO_V4_TAG_MAXCNT && 1854 doi_def->tags[iter] != CIPSO_V4_TAG_INVALID); 1855 if (ret_val < 0) 1856 return ret_val; 1857 cipso_v4_gentag_hdr(doi_def, buf, ret_val); 1858 return CIPSO_V4_HDR_LEN + ret_val; 1859 } 1860 1861 /** 1862 * cipso_v4_sock_setattr - Add a CIPSO option to a socket 1863 * @sk: the socket 1864 * @doi_def: the CIPSO DOI to use 1865 * @secattr: the specific security attributes of the socket 1866 * 1867 * Description: 1868 * Set the CIPSO option on the given socket using the DOI definition and 1869 * security attributes passed to the function. This function requires 1870 * exclusive access to @sk, which means it either needs to be in the 1871 * process of being created or locked. Returns zero on success and negative 1872 * values on failure. 1873 * 1874 */ 1875 int cipso_v4_sock_setattr(struct sock *sk, 1876 const struct cipso_v4_doi *doi_def, 1877 const struct netlbl_lsm_secattr *secattr) 1878 { 1879 int ret_val = -EPERM; 1880 unsigned char *buf = NULL; 1881 u32 buf_len; 1882 u32 opt_len; 1883 struct ip_options *opt = NULL; 1884 struct inet_sock *sk_inet; 1885 struct inet_connection_sock *sk_conn; 1886 1887 /* In the case of sock_create_lite(), the sock->sk field is not 1888 * defined yet but it is not a problem as the only users of these 1889 * "lite" PF_INET sockets are functions which do an accept() call 1890 * afterwards so we will label the socket as part of the accept(). */ 1891 if (sk == NULL) 1892 return 0; 1893 1894 /* We allocate the maximum CIPSO option size here so we are probably 1895 * being a little wasteful, but it makes our life _much_ easier later 1896 * on and after all we are only talking about 40 bytes. */ 1897 buf_len = CIPSO_V4_OPT_LEN_MAX; 1898 buf = kmalloc(buf_len, GFP_ATOMIC); 1899 if (buf == NULL) { 1900 ret_val = -ENOMEM; 1901 goto socket_setattr_failure; 1902 } 1903 1904 ret_val = cipso_v4_genopt(buf, buf_len, doi_def, secattr); 1905 if (ret_val < 0) 1906 goto socket_setattr_failure; 1907 buf_len = ret_val; 1908 1909 /* We can't use ip_options_get() directly because it makes a call to 1910 * ip_options_get_alloc() which allocates memory with GFP_KERNEL and 1911 * we won't always have CAP_NET_RAW even though we _always_ want to 1912 * set the IPOPT_CIPSO option. */ 1913 opt_len = (buf_len + 3) & ~3; 1914 opt = kzalloc(sizeof(*opt) + opt_len, GFP_ATOMIC); 1915 if (opt == NULL) { 1916 ret_val = -ENOMEM; 1917 goto socket_setattr_failure; 1918 } 1919 memcpy(opt->__data, buf, buf_len); 1920 opt->optlen = opt_len; 1921 opt->cipso = sizeof(struct iphdr); 1922 kfree(buf); 1923 buf = NULL; 1924 1925 sk_inet = inet_sk(sk); 1926 if (sk_inet->is_icsk) { 1927 sk_conn = inet_csk(sk); 1928 if (sk_inet->opt) 1929 sk_conn->icsk_ext_hdr_len -= sk_inet->opt->optlen; 1930 sk_conn->icsk_ext_hdr_len += opt->optlen; 1931 sk_conn->icsk_sync_mss(sk, sk_conn->icsk_pmtu_cookie); 1932 } 1933 opt = xchg(&sk_inet->opt, opt); 1934 kfree(opt); 1935 1936 return 0; 1937 1938 socket_setattr_failure: 1939 kfree(buf); 1940 kfree(opt); 1941 return ret_val; 1942 } 1943 1944 /** 1945 * cipso_v4_req_setattr - Add a CIPSO option to a connection request socket 1946 * @req: the connection request socket 1947 * @doi_def: the CIPSO DOI to use 1948 * @secattr: the specific security attributes of the socket 1949 * 1950 * Description: 1951 * Set the CIPSO option on the given socket using the DOI definition and 1952 * security attributes passed to the function. Returns zero on success and 1953 * negative values on failure. 1954 * 1955 */ 1956 int cipso_v4_req_setattr(struct request_sock *req, 1957 const struct cipso_v4_doi *doi_def, 1958 const struct netlbl_lsm_secattr *secattr) 1959 { 1960 int ret_val = -EPERM; 1961 unsigned char *buf = NULL; 1962 u32 buf_len; 1963 u32 opt_len; 1964 struct ip_options *opt = NULL; 1965 struct inet_request_sock *req_inet; 1966 1967 /* We allocate the maximum CIPSO option size here so we are probably 1968 * being a little wasteful, but it makes our life _much_ easier later 1969 * on and after all we are only talking about 40 bytes. */ 1970 buf_len = CIPSO_V4_OPT_LEN_MAX; 1971 buf = kmalloc(buf_len, GFP_ATOMIC); 1972 if (buf == NULL) { 1973 ret_val = -ENOMEM; 1974 goto req_setattr_failure; 1975 } 1976 1977 ret_val = cipso_v4_genopt(buf, buf_len, doi_def, secattr); 1978 if (ret_val < 0) 1979 goto req_setattr_failure; 1980 buf_len = ret_val; 1981 1982 /* We can't use ip_options_get() directly because it makes a call to 1983 * ip_options_get_alloc() which allocates memory with GFP_KERNEL and 1984 * we won't always have CAP_NET_RAW even though we _always_ want to 1985 * set the IPOPT_CIPSO option. */ 1986 opt_len = (buf_len + 3) & ~3; 1987 opt = kzalloc(sizeof(*opt) + opt_len, GFP_ATOMIC); 1988 if (opt == NULL) { 1989 ret_val = -ENOMEM; 1990 goto req_setattr_failure; 1991 } 1992 memcpy(opt->__data, buf, buf_len); 1993 opt->optlen = opt_len; 1994 opt->cipso = sizeof(struct iphdr); 1995 kfree(buf); 1996 buf = NULL; 1997 1998 req_inet = inet_rsk(req); 1999 opt = xchg(&req_inet->opt, opt); 2000 kfree(opt); 2001 2002 return 0; 2003 2004 req_setattr_failure: 2005 kfree(buf); 2006 kfree(opt); 2007 return ret_val; 2008 } 2009 2010 /** 2011 * cipso_v4_delopt - Delete the CIPSO option from a set of IP options 2012 * @opt_ptr: IP option pointer 2013 * 2014 * Description: 2015 * Deletes the CIPSO IP option from a set of IP options and makes the necessary 2016 * adjustments to the IP option structure. Returns zero on success, negative 2017 * values on failure. 2018 * 2019 */ 2020 int cipso_v4_delopt(struct ip_options **opt_ptr) 2021 { 2022 int hdr_delta = 0; 2023 struct ip_options *opt = *opt_ptr; 2024 2025 if (opt->srr || opt->rr || opt->ts || opt->router_alert) { 2026 u8 cipso_len; 2027 u8 cipso_off; 2028 unsigned char *cipso_ptr; 2029 int iter; 2030 int optlen_new; 2031 2032 cipso_off = opt->cipso - sizeof(struct iphdr); 2033 cipso_ptr = &opt->__data[cipso_off]; 2034 cipso_len = cipso_ptr[1]; 2035 2036 if (opt->srr > opt->cipso) 2037 opt->srr -= cipso_len; 2038 if (opt->rr > opt->cipso) 2039 opt->rr -= cipso_len; 2040 if (opt->ts > opt->cipso) 2041 opt->ts -= cipso_len; 2042 if (opt->router_alert > opt->cipso) 2043 opt->router_alert -= cipso_len; 2044 opt->cipso = 0; 2045 2046 memmove(cipso_ptr, cipso_ptr + cipso_len, 2047 opt->optlen - cipso_off - cipso_len); 2048 2049 /* determining the new total option length is tricky because of 2050 * the padding necessary, the only thing i can think to do at 2051 * this point is walk the options one-by-one, skipping the 2052 * padding at the end to determine the actual option size and 2053 * from there we can determine the new total option length */ 2054 iter = 0; 2055 optlen_new = 0; 2056 while (iter < opt->optlen) 2057 if (opt->__data[iter] != IPOPT_NOP) { 2058 iter += opt->__data[iter + 1]; 2059 optlen_new = iter; 2060 } else 2061 iter++; 2062 hdr_delta = opt->optlen; 2063 opt->optlen = (optlen_new + 3) & ~3; 2064 hdr_delta -= opt->optlen; 2065 } else { 2066 /* only the cipso option was present on the socket so we can 2067 * remove the entire option struct */ 2068 *opt_ptr = NULL; 2069 hdr_delta = opt->optlen; 2070 kfree(opt); 2071 } 2072 2073 return hdr_delta; 2074 } 2075 2076 /** 2077 * cipso_v4_sock_delattr - Delete the CIPSO option from a socket 2078 * @sk: the socket 2079 * 2080 * Description: 2081 * Removes the CIPSO option from a socket, if present. 2082 * 2083 */ 2084 void cipso_v4_sock_delattr(struct sock *sk) 2085 { 2086 int hdr_delta; 2087 struct ip_options *opt; 2088 struct inet_sock *sk_inet; 2089 2090 sk_inet = inet_sk(sk); 2091 opt = sk_inet->opt; 2092 if (opt == NULL || opt->cipso == 0) 2093 return; 2094 2095 hdr_delta = cipso_v4_delopt(&sk_inet->opt); 2096 if (sk_inet->is_icsk && hdr_delta > 0) { 2097 struct inet_connection_sock *sk_conn = inet_csk(sk); 2098 sk_conn->icsk_ext_hdr_len -= hdr_delta; 2099 sk_conn->icsk_sync_mss(sk, sk_conn->icsk_pmtu_cookie); 2100 } 2101 } 2102 2103 /** 2104 * cipso_v4_req_delattr - Delete the CIPSO option from a request socket 2105 * @reg: the request socket 2106 * 2107 * Description: 2108 * Removes the CIPSO option from a request socket, if present. 2109 * 2110 */ 2111 void cipso_v4_req_delattr(struct request_sock *req) 2112 { 2113 struct ip_options *opt; 2114 struct inet_request_sock *req_inet; 2115 2116 req_inet = inet_rsk(req); 2117 opt = req_inet->opt; 2118 if (opt == NULL || opt->cipso == 0) 2119 return; 2120 2121 cipso_v4_delopt(&req_inet->opt); 2122 } 2123 2124 /** 2125 * cipso_v4_getattr - Helper function for the cipso_v4_*_getattr functions 2126 * @cipso: the CIPSO v4 option 2127 * @secattr: the security attributes 2128 * 2129 * Description: 2130 * Inspect @cipso and return the security attributes in @secattr. Returns zero 2131 * on success and negative values on failure. 2132 * 2133 */ 2134 static int cipso_v4_getattr(const unsigned char *cipso, 2135 struct netlbl_lsm_secattr *secattr) 2136 { 2137 int ret_val = -ENOMSG; 2138 u32 doi; 2139 struct cipso_v4_doi *doi_def; 2140 2141 if (cipso_v4_cache_check(cipso, cipso[1], secattr) == 0) 2142 return 0; 2143 2144 doi = get_unaligned_be32(&cipso[2]); 2145 rcu_read_lock(); 2146 doi_def = cipso_v4_doi_search(doi); 2147 if (doi_def == NULL) 2148 goto getattr_return; 2149 /* XXX - This code assumes only one tag per CIPSO option which isn't 2150 * really a good assumption to make but since we only support the MAC 2151 * tags right now it is a safe assumption. */ 2152 switch (cipso[6]) { 2153 case CIPSO_V4_TAG_RBITMAP: 2154 ret_val = cipso_v4_parsetag_rbm(doi_def, &cipso[6], secattr); 2155 break; 2156 case CIPSO_V4_TAG_ENUM: 2157 ret_val = cipso_v4_parsetag_enum(doi_def, &cipso[6], secattr); 2158 break; 2159 case CIPSO_V4_TAG_RANGE: 2160 ret_val = cipso_v4_parsetag_rng(doi_def, &cipso[6], secattr); 2161 break; 2162 case CIPSO_V4_TAG_LOCAL: 2163 ret_val = cipso_v4_parsetag_loc(doi_def, &cipso[6], secattr); 2164 break; 2165 } 2166 if (ret_val == 0) 2167 secattr->type = NETLBL_NLTYPE_CIPSOV4; 2168 2169 getattr_return: 2170 rcu_read_unlock(); 2171 return ret_val; 2172 } 2173 2174 /** 2175 * cipso_v4_sock_getattr - Get the security attributes from a sock 2176 * @sk: the sock 2177 * @secattr: the security attributes 2178 * 2179 * Description: 2180 * Query @sk to see if there is a CIPSO option attached to the sock and if 2181 * there is return the CIPSO security attributes in @secattr. This function 2182 * requires that @sk be locked, or privately held, but it does not do any 2183 * locking itself. Returns zero on success and negative values on failure. 2184 * 2185 */ 2186 int cipso_v4_sock_getattr(struct sock *sk, struct netlbl_lsm_secattr *secattr) 2187 { 2188 struct ip_options *opt; 2189 2190 opt = inet_sk(sk)->opt; 2191 if (opt == NULL || opt->cipso == 0) 2192 return -ENOMSG; 2193 2194 return cipso_v4_getattr(opt->__data + opt->cipso - sizeof(struct iphdr), 2195 secattr); 2196 } 2197 2198 /** 2199 * cipso_v4_skbuff_setattr - Set the CIPSO option on a packet 2200 * @skb: the packet 2201 * @secattr: the security attributes 2202 * 2203 * Description: 2204 * Set the CIPSO option on the given packet based on the security attributes. 2205 * Returns a pointer to the IP header on success and NULL on failure. 2206 * 2207 */ 2208 int cipso_v4_skbuff_setattr(struct sk_buff *skb, 2209 const struct cipso_v4_doi *doi_def, 2210 const struct netlbl_lsm_secattr *secattr) 2211 { 2212 int ret_val; 2213 struct iphdr *iph; 2214 struct ip_options *opt = &IPCB(skb)->opt; 2215 unsigned char buf[CIPSO_V4_OPT_LEN_MAX]; 2216 u32 buf_len = CIPSO_V4_OPT_LEN_MAX; 2217 u32 opt_len; 2218 int len_delta; 2219 2220 ret_val = cipso_v4_genopt(buf, buf_len, doi_def, secattr); 2221 if (ret_val < 0) 2222 return ret_val; 2223 buf_len = ret_val; 2224 opt_len = (buf_len + 3) & ~3; 2225 2226 /* we overwrite any existing options to ensure that we have enough 2227 * room for the CIPSO option, the reason is that we _need_ to guarantee 2228 * that the security label is applied to the packet - we do the same 2229 * thing when using the socket options and it hasn't caused a problem, 2230 * if we need to we can always revisit this choice later */ 2231 2232 len_delta = opt_len - opt->optlen; 2233 /* if we don't ensure enough headroom we could panic on the skb_push() 2234 * call below so make sure we have enough, we are also "mangling" the 2235 * packet so we should probably do a copy-on-write call anyway */ 2236 ret_val = skb_cow(skb, skb_headroom(skb) + len_delta); 2237 if (ret_val < 0) 2238 return ret_val; 2239 2240 if (len_delta > 0) { 2241 /* we assume that the header + opt->optlen have already been 2242 * "pushed" in ip_options_build() or similar */ 2243 iph = ip_hdr(skb); 2244 skb_push(skb, len_delta); 2245 memmove((char *)iph - len_delta, iph, iph->ihl << 2); 2246 skb_reset_network_header(skb); 2247 iph = ip_hdr(skb); 2248 } else if (len_delta < 0) { 2249 iph = ip_hdr(skb); 2250 memset(iph + 1, IPOPT_NOP, opt->optlen); 2251 } else 2252 iph = ip_hdr(skb); 2253 2254 if (opt->optlen > 0) 2255 memset(opt, 0, sizeof(*opt)); 2256 opt->optlen = opt_len; 2257 opt->cipso = sizeof(struct iphdr); 2258 opt->is_changed = 1; 2259 2260 /* we have to do the following because we are being called from a 2261 * netfilter hook which means the packet already has had the header 2262 * fields populated and the checksum calculated - yes this means we 2263 * are doing more work than needed but we do it to keep the core 2264 * stack clean and tidy */ 2265 memcpy(iph + 1, buf, buf_len); 2266 if (opt_len > buf_len) 2267 memset((char *)(iph + 1) + buf_len, 0, opt_len - buf_len); 2268 if (len_delta != 0) { 2269 iph->ihl = 5 + (opt_len >> 2); 2270 iph->tot_len = htons(skb->len); 2271 } 2272 ip_send_check(iph); 2273 2274 return 0; 2275 } 2276 2277 /** 2278 * cipso_v4_skbuff_delattr - Delete any CIPSO options from a packet 2279 * @skb: the packet 2280 * 2281 * Description: 2282 * Removes any and all CIPSO options from the given packet. Returns zero on 2283 * success, negative values on failure. 2284 * 2285 */ 2286 int cipso_v4_skbuff_delattr(struct sk_buff *skb) 2287 { 2288 int ret_val; 2289 struct iphdr *iph; 2290 struct ip_options *opt = &IPCB(skb)->opt; 2291 unsigned char *cipso_ptr; 2292 2293 if (opt->cipso == 0) 2294 return 0; 2295 2296 /* since we are changing the packet we should make a copy */ 2297 ret_val = skb_cow(skb, skb_headroom(skb)); 2298 if (ret_val < 0) 2299 return ret_val; 2300 2301 /* the easiest thing to do is just replace the cipso option with noop 2302 * options since we don't change the size of the packet, although we 2303 * still need to recalculate the checksum */ 2304 2305 iph = ip_hdr(skb); 2306 cipso_ptr = (unsigned char *)iph + opt->cipso; 2307 memset(cipso_ptr, IPOPT_NOOP, cipso_ptr[1]); 2308 opt->cipso = 0; 2309 opt->is_changed = 1; 2310 2311 ip_send_check(iph); 2312 2313 return 0; 2314 } 2315 2316 /** 2317 * cipso_v4_skbuff_getattr - Get the security attributes from the CIPSO option 2318 * @skb: the packet 2319 * @secattr: the security attributes 2320 * 2321 * Description: 2322 * Parse the given packet's CIPSO option and return the security attributes. 2323 * Returns zero on success and negative values on failure. 2324 * 2325 */ 2326 int cipso_v4_skbuff_getattr(const struct sk_buff *skb, 2327 struct netlbl_lsm_secattr *secattr) 2328 { 2329 return cipso_v4_getattr(CIPSO_V4_OPTPTR(skb), secattr); 2330 } 2331 2332 /* 2333 * Setup Functions 2334 */ 2335 2336 /** 2337 * cipso_v4_init - Initialize the CIPSO module 2338 * 2339 * Description: 2340 * Initialize the CIPSO module and prepare it for use. Returns zero on success 2341 * and negative values on failure. 2342 * 2343 */ 2344 static int __init cipso_v4_init(void) 2345 { 2346 int ret_val; 2347 2348 ret_val = cipso_v4_cache_init(); 2349 if (ret_val != 0) 2350 panic("Failed to initialize the CIPSO/IPv4 cache (%d)\n", 2351 ret_val); 2352 2353 return 0; 2354 } 2355 2356 subsys_initcall(cipso_v4_init); 2357