1 /* 2 * CIPSO - Commercial IP Security Option 3 * 4 * This is an implementation of the CIPSO 2.2 protocol as specified in 5 * draft-ietf-cipso-ipsecurity-01.txt with additional tag types as found in 6 * FIPS-188. While CIPSO never became a full IETF RFC standard many vendors 7 * have chosen to adopt the protocol and over the years it has become a 8 * de-facto standard for labeled networking. 9 * 10 * The CIPSO draft specification can be found in the kernel's Documentation 11 * directory as well as the following URL: 12 * http://tools.ietf.org/id/draft-ietf-cipso-ipsecurity-01.txt 13 * The FIPS-188 specification can be found at the following URL: 14 * http://www.itl.nist.gov/fipspubs/fip188.htm 15 * 16 * Author: Paul Moore <paul.moore@hp.com> 17 * 18 */ 19 20 /* 21 * (c) Copyright Hewlett-Packard Development Company, L.P., 2006, 2008 22 * 23 * This program is free software; you can redistribute it and/or modify 24 * it under the terms of the GNU General Public License as published by 25 * the Free Software Foundation; either version 2 of the License, or 26 * (at your option) any later version. 27 * 28 * This program is distributed in the hope that it will be useful, 29 * but WITHOUT ANY WARRANTY; without even the implied warranty of 30 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See 31 * the GNU General Public License for more details. 32 * 33 * You should have received a copy of the GNU General Public License 34 * along with this program; if not, see <http://www.gnu.org/licenses/>. 35 * 36 */ 37 38 #include <linux/init.h> 39 #include <linux/types.h> 40 #include <linux/rcupdate.h> 41 #include <linux/list.h> 42 #include <linux/spinlock.h> 43 #include <linux/string.h> 44 #include <linux/jhash.h> 45 #include <linux/audit.h> 46 #include <linux/slab.h> 47 #include <net/ip.h> 48 #include <net/icmp.h> 49 #include <net/tcp.h> 50 #include <net/netlabel.h> 51 #include <net/cipso_ipv4.h> 52 #include <linux/atomic.h> 53 #include <linux/bug.h> 54 #include <asm/unaligned.h> 55 56 /* List of available DOI definitions */ 57 /* XXX - This currently assumes a minimal number of different DOIs in use, 58 * if in practice there are a lot of different DOIs this list should 59 * probably be turned into a hash table or something similar so we 60 * can do quick lookups. */ 61 static DEFINE_SPINLOCK(cipso_v4_doi_list_lock); 62 static LIST_HEAD(cipso_v4_doi_list); 63 64 /* Label mapping cache */ 65 int cipso_v4_cache_enabled = 1; 66 int cipso_v4_cache_bucketsize = 10; 67 #define CIPSO_V4_CACHE_BUCKETBITS 7 68 #define CIPSO_V4_CACHE_BUCKETS (1 << CIPSO_V4_CACHE_BUCKETBITS) 69 #define CIPSO_V4_CACHE_REORDERLIMIT 10 70 struct cipso_v4_map_cache_bkt { 71 spinlock_t lock; 72 u32 size; 73 struct list_head list; 74 }; 75 76 struct cipso_v4_map_cache_entry { 77 u32 hash; 78 unsigned char *key; 79 size_t key_len; 80 81 struct netlbl_lsm_cache *lsm_data; 82 83 u32 activity; 84 struct list_head list; 85 }; 86 87 static struct cipso_v4_map_cache_bkt *cipso_v4_cache; 88 89 /* Restricted bitmap (tag #1) flags */ 90 int cipso_v4_rbm_optfmt = 0; 91 int cipso_v4_rbm_strictvalid = 1; 92 93 /* 94 * Protocol Constants 95 */ 96 97 /* Maximum size of the CIPSO IP option, derived from the fact that the maximum 98 * IPv4 header size is 60 bytes and the base IPv4 header is 20 bytes long. */ 99 #define CIPSO_V4_OPT_LEN_MAX 40 100 101 /* Length of the base CIPSO option, this includes the option type (1 byte), the 102 * option length (1 byte), and the DOI (4 bytes). */ 103 #define CIPSO_V4_HDR_LEN 6 104 105 /* Base length of the restrictive category bitmap tag (tag #1). */ 106 #define CIPSO_V4_TAG_RBM_BLEN 4 107 108 /* Base length of the enumerated category tag (tag #2). */ 109 #define CIPSO_V4_TAG_ENUM_BLEN 4 110 111 /* Base length of the ranged categories bitmap tag (tag #5). */ 112 #define CIPSO_V4_TAG_RNG_BLEN 4 113 /* The maximum number of category ranges permitted in the ranged category tag 114 * (tag #5). You may note that the IETF draft states that the maximum number 115 * of category ranges is 7, but if the low end of the last category range is 116 * zero then it is possible to fit 8 category ranges because the zero should 117 * be omitted. */ 118 #define CIPSO_V4_TAG_RNG_CAT_MAX 8 119 120 /* Base length of the local tag (non-standard tag). 121 * Tag definition (may change between kernel versions) 122 * 123 * 0 8 16 24 32 124 * +----------+----------+----------+----------+ 125 * | 10000000 | 00000110 | 32-bit secid value | 126 * +----------+----------+----------+----------+ 127 * | in (host byte order)| 128 * +----------+----------+ 129 * 130 */ 131 #define CIPSO_V4_TAG_LOC_BLEN 6 132 133 /* 134 * Helper Functions 135 */ 136 137 /** 138 * cipso_v4_bitmap_walk - Walk a bitmap looking for a bit 139 * @bitmap: the bitmap 140 * @bitmap_len: length in bits 141 * @offset: starting offset 142 * @state: if non-zero, look for a set (1) bit else look for a cleared (0) bit 143 * 144 * Description: 145 * Starting at @offset, walk the bitmap from left to right until either the 146 * desired bit is found or we reach the end. Return the bit offset, -1 if 147 * not found, or -2 if error. 148 */ 149 static int cipso_v4_bitmap_walk(const unsigned char *bitmap, 150 u32 bitmap_len, 151 u32 offset, 152 u8 state) 153 { 154 u32 bit_spot; 155 u32 byte_offset; 156 unsigned char bitmask; 157 unsigned char byte; 158 159 /* gcc always rounds to zero when doing integer division */ 160 byte_offset = offset / 8; 161 byte = bitmap[byte_offset]; 162 bit_spot = offset; 163 bitmask = 0x80 >> (offset % 8); 164 165 while (bit_spot < bitmap_len) { 166 if ((state && (byte & bitmask) == bitmask) || 167 (state == 0 && (byte & bitmask) == 0)) 168 return bit_spot; 169 170 bit_spot++; 171 bitmask >>= 1; 172 if (bitmask == 0) { 173 byte = bitmap[++byte_offset]; 174 bitmask = 0x80; 175 } 176 } 177 178 return -1; 179 } 180 181 /** 182 * cipso_v4_bitmap_setbit - Sets a single bit in a bitmap 183 * @bitmap: the bitmap 184 * @bit: the bit 185 * @state: if non-zero, set the bit (1) else clear the bit (0) 186 * 187 * Description: 188 * Set a single bit in the bitmask. Returns zero on success, negative values 189 * on error. 190 */ 191 static void cipso_v4_bitmap_setbit(unsigned char *bitmap, 192 u32 bit, 193 u8 state) 194 { 195 u32 byte_spot; 196 u8 bitmask; 197 198 /* gcc always rounds to zero when doing integer division */ 199 byte_spot = bit / 8; 200 bitmask = 0x80 >> (bit % 8); 201 if (state) 202 bitmap[byte_spot] |= bitmask; 203 else 204 bitmap[byte_spot] &= ~bitmask; 205 } 206 207 /** 208 * cipso_v4_cache_entry_free - Frees a cache entry 209 * @entry: the entry to free 210 * 211 * Description: 212 * This function frees the memory associated with a cache entry including the 213 * LSM cache data if there are no longer any users, i.e. reference count == 0. 214 * 215 */ 216 static void cipso_v4_cache_entry_free(struct cipso_v4_map_cache_entry *entry) 217 { 218 if (entry->lsm_data) 219 netlbl_secattr_cache_free(entry->lsm_data); 220 kfree(entry->key); 221 kfree(entry); 222 } 223 224 /** 225 * cipso_v4_map_cache_hash - Hashing function for the CIPSO cache 226 * @key: the hash key 227 * @key_len: the length of the key in bytes 228 * 229 * Description: 230 * The CIPSO tag hashing function. Returns a 32-bit hash value. 231 * 232 */ 233 static u32 cipso_v4_map_cache_hash(const unsigned char *key, u32 key_len) 234 { 235 return jhash(key, key_len, 0); 236 } 237 238 /* 239 * Label Mapping Cache Functions 240 */ 241 242 /** 243 * cipso_v4_cache_init - Initialize the CIPSO cache 244 * 245 * Description: 246 * Initializes the CIPSO label mapping cache, this function should be called 247 * before any of the other functions defined in this file. Returns zero on 248 * success, negative values on error. 249 * 250 */ 251 static int __init cipso_v4_cache_init(void) 252 { 253 u32 iter; 254 255 cipso_v4_cache = kcalloc(CIPSO_V4_CACHE_BUCKETS, 256 sizeof(struct cipso_v4_map_cache_bkt), 257 GFP_KERNEL); 258 if (cipso_v4_cache == NULL) 259 return -ENOMEM; 260 261 for (iter = 0; iter < CIPSO_V4_CACHE_BUCKETS; iter++) { 262 spin_lock_init(&cipso_v4_cache[iter].lock); 263 cipso_v4_cache[iter].size = 0; 264 INIT_LIST_HEAD(&cipso_v4_cache[iter].list); 265 } 266 267 return 0; 268 } 269 270 /** 271 * cipso_v4_cache_invalidate - Invalidates the current CIPSO cache 272 * 273 * Description: 274 * Invalidates and frees any entries in the CIPSO cache. Returns zero on 275 * success and negative values on failure. 276 * 277 */ 278 void cipso_v4_cache_invalidate(void) 279 { 280 struct cipso_v4_map_cache_entry *entry, *tmp_entry; 281 u32 iter; 282 283 for (iter = 0; iter < CIPSO_V4_CACHE_BUCKETS; iter++) { 284 spin_lock_bh(&cipso_v4_cache[iter].lock); 285 list_for_each_entry_safe(entry, 286 tmp_entry, 287 &cipso_v4_cache[iter].list, list) { 288 list_del(&entry->list); 289 cipso_v4_cache_entry_free(entry); 290 } 291 cipso_v4_cache[iter].size = 0; 292 spin_unlock_bh(&cipso_v4_cache[iter].lock); 293 } 294 } 295 296 /** 297 * cipso_v4_cache_check - Check the CIPSO cache for a label mapping 298 * @key: the buffer to check 299 * @key_len: buffer length in bytes 300 * @secattr: the security attribute struct to use 301 * 302 * Description: 303 * This function checks the cache to see if a label mapping already exists for 304 * the given key. If there is a match then the cache is adjusted and the 305 * @secattr struct is populated with the correct LSM security attributes. The 306 * cache is adjusted in the following manner if the entry is not already the 307 * first in the cache bucket: 308 * 309 * 1. The cache entry's activity counter is incremented 310 * 2. The previous (higher ranking) entry's activity counter is decremented 311 * 3. If the difference between the two activity counters is geater than 312 * CIPSO_V4_CACHE_REORDERLIMIT the two entries are swapped 313 * 314 * Returns zero on success, -ENOENT for a cache miss, and other negative values 315 * on error. 316 * 317 */ 318 static int cipso_v4_cache_check(const unsigned char *key, 319 u32 key_len, 320 struct netlbl_lsm_secattr *secattr) 321 { 322 u32 bkt; 323 struct cipso_v4_map_cache_entry *entry; 324 struct cipso_v4_map_cache_entry *prev_entry = NULL; 325 u32 hash; 326 327 if (!cipso_v4_cache_enabled) 328 return -ENOENT; 329 330 hash = cipso_v4_map_cache_hash(key, key_len); 331 bkt = hash & (CIPSO_V4_CACHE_BUCKETS - 1); 332 spin_lock_bh(&cipso_v4_cache[bkt].lock); 333 list_for_each_entry(entry, &cipso_v4_cache[bkt].list, list) { 334 if (entry->hash == hash && 335 entry->key_len == key_len && 336 memcmp(entry->key, key, key_len) == 0) { 337 entry->activity += 1; 338 atomic_inc(&entry->lsm_data->refcount); 339 secattr->cache = entry->lsm_data; 340 secattr->flags |= NETLBL_SECATTR_CACHE; 341 secattr->type = NETLBL_NLTYPE_CIPSOV4; 342 if (prev_entry == 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 responsible 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->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 * @doi_def: the DOI definition 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_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_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_catmap_walk(secattr->attr.mls.cat, cat + 1); 1045 if (cat < 0) 1046 break; 1047 if ((cat_iter + 2) > net_cat_len) 1048 return -ENOSPC; 1049 1050 *((__be16 *)&net_cat[cat_iter]) = htons(cat); 1051 cat_iter += 2; 1052 } 1053 1054 return cat_iter; 1055 } 1056 1057 /** 1058 * cipso_v4_map_cat_enum_ntoh - Perform a category mapping from network to host 1059 * @doi_def: the DOI definition 1060 * @net_cat: the category list in network/CIPSO format 1061 * @net_cat_len: the length of the CIPSO bitmap in bytes 1062 * @secattr: the security attributes 1063 * 1064 * Description: 1065 * Perform a label mapping to translate a CIPSO category list to the correct 1066 * local MLS category bitmap using the given DOI definition. Returns zero on 1067 * success, negative values on failure. 1068 * 1069 */ 1070 static int cipso_v4_map_cat_enum_ntoh(const struct cipso_v4_doi *doi_def, 1071 const unsigned char *net_cat, 1072 u32 net_cat_len, 1073 struct netlbl_lsm_secattr *secattr) 1074 { 1075 int ret_val; 1076 u32 iter; 1077 1078 for (iter = 0; iter < net_cat_len; iter += 2) { 1079 ret_val = netlbl_catmap_setbit(&secattr->attr.mls.cat, 1080 get_unaligned_be16(&net_cat[iter]), 1081 GFP_ATOMIC); 1082 if (ret_val != 0) 1083 return ret_val; 1084 } 1085 1086 return 0; 1087 } 1088 1089 /** 1090 * cipso_v4_map_cat_rng_valid - Checks to see if the categories are valid 1091 * @doi_def: the DOI definition 1092 * @rngcat: category list 1093 * @rngcat_len: length of the category list in bytes 1094 * 1095 * Description: 1096 * Checks the given categories against the given DOI definition and returns a 1097 * negative value if any of the categories do not have a valid mapping and a 1098 * zero value if all of the categories are valid. 1099 * 1100 */ 1101 static int cipso_v4_map_cat_rng_valid(const struct cipso_v4_doi *doi_def, 1102 const unsigned char *rngcat, 1103 u32 rngcat_len) 1104 { 1105 u16 cat_high; 1106 u16 cat_low; 1107 u32 cat_prev = CIPSO_V4_MAX_REM_CATS + 1; 1108 u32 iter; 1109 1110 if (doi_def->type != CIPSO_V4_MAP_PASS || rngcat_len & 0x01) 1111 return -EFAULT; 1112 1113 for (iter = 0; iter < rngcat_len; iter += 4) { 1114 cat_high = get_unaligned_be16(&rngcat[iter]); 1115 if ((iter + 4) <= rngcat_len) 1116 cat_low = get_unaligned_be16(&rngcat[iter + 2]); 1117 else 1118 cat_low = 0; 1119 1120 if (cat_high > cat_prev) 1121 return -EFAULT; 1122 1123 cat_prev = cat_low; 1124 } 1125 1126 return 0; 1127 } 1128 1129 /** 1130 * cipso_v4_map_cat_rng_hton - Perform a category mapping from host to network 1131 * @doi_def: the DOI definition 1132 * @secattr: the security attributes 1133 * @net_cat: the zero'd out category list in network/CIPSO format 1134 * @net_cat_len: the length of the CIPSO category list in bytes 1135 * 1136 * Description: 1137 * Perform a label mapping to translate a local MLS category bitmap to the 1138 * correct CIPSO category list using the given DOI definition. Returns the 1139 * size in bytes of the network category bitmap on success, negative values 1140 * otherwise. 1141 * 1142 */ 1143 static int cipso_v4_map_cat_rng_hton(const struct cipso_v4_doi *doi_def, 1144 const struct netlbl_lsm_secattr *secattr, 1145 unsigned char *net_cat, 1146 u32 net_cat_len) 1147 { 1148 int iter = -1; 1149 u16 array[CIPSO_V4_TAG_RNG_CAT_MAX * 2]; 1150 u32 array_cnt = 0; 1151 u32 cat_size = 0; 1152 1153 /* make sure we don't overflow the 'array[]' variable */ 1154 if (net_cat_len > 1155 (CIPSO_V4_OPT_LEN_MAX - CIPSO_V4_HDR_LEN - CIPSO_V4_TAG_RNG_BLEN)) 1156 return -ENOSPC; 1157 1158 for (;;) { 1159 iter = netlbl_catmap_walk(secattr->attr.mls.cat, iter + 1); 1160 if (iter < 0) 1161 break; 1162 cat_size += (iter == 0 ? 0 : sizeof(u16)); 1163 if (cat_size > net_cat_len) 1164 return -ENOSPC; 1165 array[array_cnt++] = iter; 1166 1167 iter = netlbl_catmap_walkrng(secattr->attr.mls.cat, iter); 1168 if (iter < 0) 1169 return -EFAULT; 1170 cat_size += sizeof(u16); 1171 if (cat_size > net_cat_len) 1172 return -ENOSPC; 1173 array[array_cnt++] = iter; 1174 } 1175 1176 for (iter = 0; array_cnt > 0;) { 1177 *((__be16 *)&net_cat[iter]) = htons(array[--array_cnt]); 1178 iter += 2; 1179 array_cnt--; 1180 if (array[array_cnt] != 0) { 1181 *((__be16 *)&net_cat[iter]) = htons(array[array_cnt]); 1182 iter += 2; 1183 } 1184 } 1185 1186 return cat_size; 1187 } 1188 1189 /** 1190 * cipso_v4_map_cat_rng_ntoh - Perform a category mapping from network to host 1191 * @doi_def: the DOI definition 1192 * @net_cat: the category list in network/CIPSO format 1193 * @net_cat_len: the length of the CIPSO bitmap in bytes 1194 * @secattr: the security attributes 1195 * 1196 * Description: 1197 * Perform a label mapping to translate a CIPSO category list to the correct 1198 * local MLS category bitmap using the given DOI definition. Returns zero on 1199 * success, negative values on failure. 1200 * 1201 */ 1202 static int cipso_v4_map_cat_rng_ntoh(const struct cipso_v4_doi *doi_def, 1203 const unsigned char *net_cat, 1204 u32 net_cat_len, 1205 struct netlbl_lsm_secattr *secattr) 1206 { 1207 int ret_val; 1208 u32 net_iter; 1209 u16 cat_low; 1210 u16 cat_high; 1211 1212 for (net_iter = 0; net_iter < net_cat_len; net_iter += 4) { 1213 cat_high = get_unaligned_be16(&net_cat[net_iter]); 1214 if ((net_iter + 4) <= net_cat_len) 1215 cat_low = get_unaligned_be16(&net_cat[net_iter + 2]); 1216 else 1217 cat_low = 0; 1218 1219 ret_val = netlbl_catmap_setrng(&secattr->attr.mls.cat, 1220 cat_low, 1221 cat_high, 1222 GFP_ATOMIC); 1223 if (ret_val != 0) 1224 return ret_val; 1225 } 1226 1227 return 0; 1228 } 1229 1230 /* 1231 * Protocol Handling Functions 1232 */ 1233 1234 /** 1235 * cipso_v4_gentag_hdr - Generate a CIPSO option header 1236 * @doi_def: the DOI definition 1237 * @len: the total tag length in bytes, not including this header 1238 * @buf: the CIPSO option buffer 1239 * 1240 * Description: 1241 * Write a CIPSO header into the beginning of @buffer. 1242 * 1243 */ 1244 static void cipso_v4_gentag_hdr(const struct cipso_v4_doi *doi_def, 1245 unsigned char *buf, 1246 u32 len) 1247 { 1248 buf[0] = IPOPT_CIPSO; 1249 buf[1] = CIPSO_V4_HDR_LEN + len; 1250 *(__be32 *)&buf[2] = htonl(doi_def->doi); 1251 } 1252 1253 /** 1254 * cipso_v4_gentag_rbm - Generate a CIPSO restricted bitmap tag (type #1) 1255 * @doi_def: the DOI definition 1256 * @secattr: the security attributes 1257 * @buffer: the option buffer 1258 * @buffer_len: length of buffer in bytes 1259 * 1260 * Description: 1261 * Generate a CIPSO option using the restricted bitmap tag, tag type #1. The 1262 * actual buffer length may be larger than the indicated size due to 1263 * translation between host and network category bitmaps. Returns the size of 1264 * the tag on success, negative values on failure. 1265 * 1266 */ 1267 static int cipso_v4_gentag_rbm(const struct cipso_v4_doi *doi_def, 1268 const struct netlbl_lsm_secattr *secattr, 1269 unsigned char *buffer, 1270 u32 buffer_len) 1271 { 1272 int ret_val; 1273 u32 tag_len; 1274 u32 level; 1275 1276 if ((secattr->flags & NETLBL_SECATTR_MLS_LVL) == 0) 1277 return -EPERM; 1278 1279 ret_val = cipso_v4_map_lvl_hton(doi_def, 1280 secattr->attr.mls.lvl, 1281 &level); 1282 if (ret_val != 0) 1283 return ret_val; 1284 1285 if (secattr->flags & NETLBL_SECATTR_MLS_CAT) { 1286 ret_val = cipso_v4_map_cat_rbm_hton(doi_def, 1287 secattr, 1288 &buffer[4], 1289 buffer_len - 4); 1290 if (ret_val < 0) 1291 return ret_val; 1292 1293 /* This will send packets using the "optimized" format when 1294 * possible as specified in section 3.4.2.6 of the 1295 * CIPSO draft. */ 1296 if (cipso_v4_rbm_optfmt && ret_val > 0 && ret_val <= 10) 1297 tag_len = 14; 1298 else 1299 tag_len = 4 + ret_val; 1300 } else 1301 tag_len = 4; 1302 1303 buffer[0] = CIPSO_V4_TAG_RBITMAP; 1304 buffer[1] = tag_len; 1305 buffer[3] = level; 1306 1307 return tag_len; 1308 } 1309 1310 /** 1311 * cipso_v4_parsetag_rbm - Parse a CIPSO restricted bitmap tag 1312 * @doi_def: the DOI definition 1313 * @tag: the CIPSO tag 1314 * @secattr: the security attributes 1315 * 1316 * Description: 1317 * Parse a CIPSO restricted bitmap tag (tag type #1) and return the security 1318 * attributes in @secattr. Return zero on success, negatives values on 1319 * failure. 1320 * 1321 */ 1322 static int cipso_v4_parsetag_rbm(const struct cipso_v4_doi *doi_def, 1323 const unsigned char *tag, 1324 struct netlbl_lsm_secattr *secattr) 1325 { 1326 int ret_val; 1327 u8 tag_len = tag[1]; 1328 u32 level; 1329 1330 ret_val = cipso_v4_map_lvl_ntoh(doi_def, tag[3], &level); 1331 if (ret_val != 0) 1332 return ret_val; 1333 secattr->attr.mls.lvl = level; 1334 secattr->flags |= NETLBL_SECATTR_MLS_LVL; 1335 1336 if (tag_len > 4) { 1337 ret_val = cipso_v4_map_cat_rbm_ntoh(doi_def, 1338 &tag[4], 1339 tag_len - 4, 1340 secattr); 1341 if (ret_val != 0) { 1342 netlbl_catmap_free(secattr->attr.mls.cat); 1343 return ret_val; 1344 } 1345 1346 secattr->flags |= NETLBL_SECATTR_MLS_CAT; 1347 } 1348 1349 return 0; 1350 } 1351 1352 /** 1353 * cipso_v4_gentag_enum - Generate a CIPSO enumerated tag (type #2) 1354 * @doi_def: the DOI definition 1355 * @secattr: the security attributes 1356 * @buffer: the option buffer 1357 * @buffer_len: length of buffer in bytes 1358 * 1359 * Description: 1360 * Generate a CIPSO option using the enumerated tag, tag type #2. Returns the 1361 * size of the tag on success, negative values on failure. 1362 * 1363 */ 1364 static int cipso_v4_gentag_enum(const struct cipso_v4_doi *doi_def, 1365 const struct netlbl_lsm_secattr *secattr, 1366 unsigned char *buffer, 1367 u32 buffer_len) 1368 { 1369 int ret_val; 1370 u32 tag_len; 1371 u32 level; 1372 1373 if (!(secattr->flags & NETLBL_SECATTR_MLS_LVL)) 1374 return -EPERM; 1375 1376 ret_val = cipso_v4_map_lvl_hton(doi_def, 1377 secattr->attr.mls.lvl, 1378 &level); 1379 if (ret_val != 0) 1380 return ret_val; 1381 1382 if (secattr->flags & NETLBL_SECATTR_MLS_CAT) { 1383 ret_val = cipso_v4_map_cat_enum_hton(doi_def, 1384 secattr, 1385 &buffer[4], 1386 buffer_len - 4); 1387 if (ret_val < 0) 1388 return ret_val; 1389 1390 tag_len = 4 + ret_val; 1391 } else 1392 tag_len = 4; 1393 1394 buffer[0] = CIPSO_V4_TAG_ENUM; 1395 buffer[1] = tag_len; 1396 buffer[3] = level; 1397 1398 return tag_len; 1399 } 1400 1401 /** 1402 * cipso_v4_parsetag_enum - Parse a CIPSO enumerated tag 1403 * @doi_def: the DOI definition 1404 * @tag: the CIPSO tag 1405 * @secattr: the security attributes 1406 * 1407 * Description: 1408 * Parse a CIPSO enumerated tag (tag type #2) and return the security 1409 * attributes in @secattr. Return zero on success, negatives values on 1410 * failure. 1411 * 1412 */ 1413 static int cipso_v4_parsetag_enum(const struct cipso_v4_doi *doi_def, 1414 const unsigned char *tag, 1415 struct netlbl_lsm_secattr *secattr) 1416 { 1417 int ret_val; 1418 u8 tag_len = tag[1]; 1419 u32 level; 1420 1421 ret_val = cipso_v4_map_lvl_ntoh(doi_def, tag[3], &level); 1422 if (ret_val != 0) 1423 return ret_val; 1424 secattr->attr.mls.lvl = level; 1425 secattr->flags |= NETLBL_SECATTR_MLS_LVL; 1426 1427 if (tag_len > 4) { 1428 ret_val = cipso_v4_map_cat_enum_ntoh(doi_def, 1429 &tag[4], 1430 tag_len - 4, 1431 secattr); 1432 if (ret_val != 0) { 1433 netlbl_catmap_free(secattr->attr.mls.cat); 1434 return ret_val; 1435 } 1436 1437 secattr->flags |= NETLBL_SECATTR_MLS_CAT; 1438 } 1439 1440 return 0; 1441 } 1442 1443 /** 1444 * cipso_v4_gentag_rng - Generate a CIPSO ranged tag (type #5) 1445 * @doi_def: the DOI definition 1446 * @secattr: the security attributes 1447 * @buffer: the option buffer 1448 * @buffer_len: length of buffer in bytes 1449 * 1450 * Description: 1451 * Generate a CIPSO option using the ranged tag, tag type #5. Returns the 1452 * size of the tag on success, negative values on failure. 1453 * 1454 */ 1455 static int cipso_v4_gentag_rng(const struct cipso_v4_doi *doi_def, 1456 const struct netlbl_lsm_secattr *secattr, 1457 unsigned char *buffer, 1458 u32 buffer_len) 1459 { 1460 int ret_val; 1461 u32 tag_len; 1462 u32 level; 1463 1464 if (!(secattr->flags & NETLBL_SECATTR_MLS_LVL)) 1465 return -EPERM; 1466 1467 ret_val = cipso_v4_map_lvl_hton(doi_def, 1468 secattr->attr.mls.lvl, 1469 &level); 1470 if (ret_val != 0) 1471 return ret_val; 1472 1473 if (secattr->flags & NETLBL_SECATTR_MLS_CAT) { 1474 ret_val = cipso_v4_map_cat_rng_hton(doi_def, 1475 secattr, 1476 &buffer[4], 1477 buffer_len - 4); 1478 if (ret_val < 0) 1479 return ret_val; 1480 1481 tag_len = 4 + ret_val; 1482 } else 1483 tag_len = 4; 1484 1485 buffer[0] = CIPSO_V4_TAG_RANGE; 1486 buffer[1] = tag_len; 1487 buffer[3] = level; 1488 1489 return tag_len; 1490 } 1491 1492 /** 1493 * cipso_v4_parsetag_rng - Parse a CIPSO ranged tag 1494 * @doi_def: the DOI definition 1495 * @tag: the CIPSO tag 1496 * @secattr: the security attributes 1497 * 1498 * Description: 1499 * Parse a CIPSO ranged tag (tag type #5) and return the security attributes 1500 * in @secattr. Return zero on success, negatives values on failure. 1501 * 1502 */ 1503 static int cipso_v4_parsetag_rng(const struct cipso_v4_doi *doi_def, 1504 const unsigned char *tag, 1505 struct netlbl_lsm_secattr *secattr) 1506 { 1507 int ret_val; 1508 u8 tag_len = tag[1]; 1509 u32 level; 1510 1511 ret_val = cipso_v4_map_lvl_ntoh(doi_def, tag[3], &level); 1512 if (ret_val != 0) 1513 return ret_val; 1514 secattr->attr.mls.lvl = level; 1515 secattr->flags |= NETLBL_SECATTR_MLS_LVL; 1516 1517 if (tag_len > 4) { 1518 ret_val = cipso_v4_map_cat_rng_ntoh(doi_def, 1519 &tag[4], 1520 tag_len - 4, 1521 secattr); 1522 if (ret_val != 0) { 1523 netlbl_catmap_free(secattr->attr.mls.cat); 1524 return ret_val; 1525 } 1526 1527 secattr->flags |= NETLBL_SECATTR_MLS_CAT; 1528 } 1529 1530 return 0; 1531 } 1532 1533 /** 1534 * cipso_v4_gentag_loc - Generate a CIPSO local tag (non-standard) 1535 * @doi_def: the DOI definition 1536 * @secattr: the security attributes 1537 * @buffer: the option buffer 1538 * @buffer_len: length of buffer in bytes 1539 * 1540 * Description: 1541 * Generate a CIPSO option using the local tag. Returns the size of the tag 1542 * on success, negative values on failure. 1543 * 1544 */ 1545 static int cipso_v4_gentag_loc(const struct cipso_v4_doi *doi_def, 1546 const struct netlbl_lsm_secattr *secattr, 1547 unsigned char *buffer, 1548 u32 buffer_len) 1549 { 1550 if (!(secattr->flags & NETLBL_SECATTR_SECID)) 1551 return -EPERM; 1552 1553 buffer[0] = CIPSO_V4_TAG_LOCAL; 1554 buffer[1] = CIPSO_V4_TAG_LOC_BLEN; 1555 *(u32 *)&buffer[2] = secattr->attr.secid; 1556 1557 return CIPSO_V4_TAG_LOC_BLEN; 1558 } 1559 1560 /** 1561 * cipso_v4_parsetag_loc - Parse a CIPSO local tag 1562 * @doi_def: the DOI definition 1563 * @tag: the CIPSO tag 1564 * @secattr: the security attributes 1565 * 1566 * Description: 1567 * Parse a CIPSO local tag and return the security attributes in @secattr. 1568 * Return zero on success, negatives values on failure. 1569 * 1570 */ 1571 static int cipso_v4_parsetag_loc(const struct cipso_v4_doi *doi_def, 1572 const unsigned char *tag, 1573 struct netlbl_lsm_secattr *secattr) 1574 { 1575 secattr->attr.secid = *(u32 *)&tag[2]; 1576 secattr->flags |= NETLBL_SECATTR_SECID; 1577 1578 return 0; 1579 } 1580 1581 /** 1582 * cipso_v4_validate - Validate a CIPSO option 1583 * @option: the start of the option, on error it is set to point to the error 1584 * 1585 * Description: 1586 * This routine is called to validate a CIPSO option, it checks all of the 1587 * fields to ensure that they are at least valid, see the draft snippet below 1588 * for details. If the option is valid then a zero value is returned and 1589 * the value of @option is unchanged. If the option is invalid then a 1590 * non-zero value is returned and @option is adjusted to point to the 1591 * offending portion of the option. From the IETF draft ... 1592 * 1593 * "If any field within the CIPSO options, such as the DOI identifier, is not 1594 * recognized the IP datagram is discarded and an ICMP 'parameter problem' 1595 * (type 12) is generated and returned. The ICMP code field is set to 'bad 1596 * parameter' (code 0) and the pointer is set to the start of the CIPSO field 1597 * that is unrecognized." 1598 * 1599 */ 1600 int cipso_v4_validate(const struct sk_buff *skb, unsigned char **option) 1601 { 1602 unsigned char *opt = *option; 1603 unsigned char *tag; 1604 unsigned char opt_iter; 1605 unsigned char err_offset = 0; 1606 u8 opt_len; 1607 u8 tag_len; 1608 struct cipso_v4_doi *doi_def = NULL; 1609 u32 tag_iter; 1610 1611 /* caller already checks for length values that are too large */ 1612 opt_len = opt[1]; 1613 if (opt_len < 8) { 1614 err_offset = 1; 1615 goto validate_return; 1616 } 1617 1618 rcu_read_lock(); 1619 doi_def = cipso_v4_doi_search(get_unaligned_be32(&opt[2])); 1620 if (doi_def == NULL) { 1621 err_offset = 2; 1622 goto validate_return_locked; 1623 } 1624 1625 opt_iter = CIPSO_V4_HDR_LEN; 1626 tag = opt + opt_iter; 1627 while (opt_iter < opt_len) { 1628 for (tag_iter = 0; doi_def->tags[tag_iter] != tag[0];) 1629 if (doi_def->tags[tag_iter] == CIPSO_V4_TAG_INVALID || 1630 ++tag_iter == CIPSO_V4_TAG_MAXCNT) { 1631 err_offset = opt_iter; 1632 goto validate_return_locked; 1633 } 1634 1635 tag_len = tag[1]; 1636 if (tag_len > (opt_len - opt_iter)) { 1637 err_offset = opt_iter + 1; 1638 goto validate_return_locked; 1639 } 1640 1641 switch (tag[0]) { 1642 case CIPSO_V4_TAG_RBITMAP: 1643 if (tag_len < CIPSO_V4_TAG_RBM_BLEN) { 1644 err_offset = opt_iter + 1; 1645 goto validate_return_locked; 1646 } 1647 1648 /* We are already going to do all the verification 1649 * necessary at the socket layer so from our point of 1650 * view it is safe to turn these checks off (and less 1651 * work), however, the CIPSO draft says we should do 1652 * all the CIPSO validations here but it doesn't 1653 * really specify _exactly_ what we need to validate 1654 * ... so, just make it a sysctl tunable. */ 1655 if (cipso_v4_rbm_strictvalid) { 1656 if (cipso_v4_map_lvl_valid(doi_def, 1657 tag[3]) < 0) { 1658 err_offset = opt_iter + 3; 1659 goto validate_return_locked; 1660 } 1661 if (tag_len > CIPSO_V4_TAG_RBM_BLEN && 1662 cipso_v4_map_cat_rbm_valid(doi_def, 1663 &tag[4], 1664 tag_len - 4) < 0) { 1665 err_offset = opt_iter + 4; 1666 goto validate_return_locked; 1667 } 1668 } 1669 break; 1670 case CIPSO_V4_TAG_ENUM: 1671 if (tag_len < CIPSO_V4_TAG_ENUM_BLEN) { 1672 err_offset = opt_iter + 1; 1673 goto validate_return_locked; 1674 } 1675 1676 if (cipso_v4_map_lvl_valid(doi_def, 1677 tag[3]) < 0) { 1678 err_offset = opt_iter + 3; 1679 goto validate_return_locked; 1680 } 1681 if (tag_len > CIPSO_V4_TAG_ENUM_BLEN && 1682 cipso_v4_map_cat_enum_valid(doi_def, 1683 &tag[4], 1684 tag_len - 4) < 0) { 1685 err_offset = opt_iter + 4; 1686 goto validate_return_locked; 1687 } 1688 break; 1689 case CIPSO_V4_TAG_RANGE: 1690 if (tag_len < CIPSO_V4_TAG_RNG_BLEN) { 1691 err_offset = opt_iter + 1; 1692 goto validate_return_locked; 1693 } 1694 1695 if (cipso_v4_map_lvl_valid(doi_def, 1696 tag[3]) < 0) { 1697 err_offset = opt_iter + 3; 1698 goto validate_return_locked; 1699 } 1700 if (tag_len > CIPSO_V4_TAG_RNG_BLEN && 1701 cipso_v4_map_cat_rng_valid(doi_def, 1702 &tag[4], 1703 tag_len - 4) < 0) { 1704 err_offset = opt_iter + 4; 1705 goto validate_return_locked; 1706 } 1707 break; 1708 case CIPSO_V4_TAG_LOCAL: 1709 /* This is a non-standard tag that we only allow for 1710 * local connections, so if the incoming interface is 1711 * not the loopback device drop the packet. Further, 1712 * there is no legitimate reason for setting this from 1713 * userspace so reject it if skb is NULL. */ 1714 if (skb == NULL || !(skb->dev->flags & IFF_LOOPBACK)) { 1715 err_offset = opt_iter; 1716 goto validate_return_locked; 1717 } 1718 if (tag_len != CIPSO_V4_TAG_LOC_BLEN) { 1719 err_offset = opt_iter + 1; 1720 goto validate_return_locked; 1721 } 1722 break; 1723 default: 1724 err_offset = opt_iter; 1725 goto validate_return_locked; 1726 } 1727 1728 tag += tag_len; 1729 opt_iter += tag_len; 1730 } 1731 1732 validate_return_locked: 1733 rcu_read_unlock(); 1734 validate_return: 1735 *option = opt + err_offset; 1736 return err_offset; 1737 } 1738 1739 /** 1740 * cipso_v4_error - Send the correct response for a bad packet 1741 * @skb: the packet 1742 * @error: the error code 1743 * @gateway: CIPSO gateway flag 1744 * 1745 * Description: 1746 * Based on the error code given in @error, send an ICMP error message back to 1747 * the originating host. From the IETF draft ... 1748 * 1749 * "If the contents of the CIPSO [option] are valid but the security label is 1750 * outside of the configured host or port label range, the datagram is 1751 * discarded and an ICMP 'destination unreachable' (type 3) is generated and 1752 * returned. The code field of the ICMP is set to 'communication with 1753 * destination network administratively prohibited' (code 9) or to 1754 * 'communication with destination host administratively prohibited' 1755 * (code 10). The value of the code is dependent on whether the originator 1756 * of the ICMP message is acting as a CIPSO host or a CIPSO gateway. The 1757 * recipient of the ICMP message MUST be able to handle either value. The 1758 * same procedure is performed if a CIPSO [option] can not be added to an 1759 * IP packet because it is too large to fit in the IP options area." 1760 * 1761 * "If the error is triggered by receipt of an ICMP message, the message is 1762 * discarded and no response is permitted (consistent with general ICMP 1763 * processing rules)." 1764 * 1765 */ 1766 void cipso_v4_error(struct sk_buff *skb, int error, u32 gateway) 1767 { 1768 if (ip_hdr(skb)->protocol == IPPROTO_ICMP || error != -EACCES) 1769 return; 1770 1771 if (gateway) 1772 icmp_send(skb, ICMP_DEST_UNREACH, ICMP_NET_ANO, 0); 1773 else 1774 icmp_send(skb, ICMP_DEST_UNREACH, ICMP_HOST_ANO, 0); 1775 } 1776 1777 /** 1778 * cipso_v4_genopt - Generate a CIPSO option 1779 * @buf: the option buffer 1780 * @buf_len: the size of opt_buf 1781 * @doi_def: the CIPSO DOI to use 1782 * @secattr: the security attributes 1783 * 1784 * Description: 1785 * Generate a CIPSO option using the DOI definition and security attributes 1786 * passed to the function. Returns the length of the option on success and 1787 * negative values on failure. 1788 * 1789 */ 1790 static int cipso_v4_genopt(unsigned char *buf, u32 buf_len, 1791 const struct cipso_v4_doi *doi_def, 1792 const struct netlbl_lsm_secattr *secattr) 1793 { 1794 int ret_val; 1795 u32 iter; 1796 1797 if (buf_len <= CIPSO_V4_HDR_LEN) 1798 return -ENOSPC; 1799 1800 /* XXX - This code assumes only one tag per CIPSO option which isn't 1801 * really a good assumption to make but since we only support the MAC 1802 * tags right now it is a safe assumption. */ 1803 iter = 0; 1804 do { 1805 memset(buf, 0, buf_len); 1806 switch (doi_def->tags[iter]) { 1807 case CIPSO_V4_TAG_RBITMAP: 1808 ret_val = cipso_v4_gentag_rbm(doi_def, 1809 secattr, 1810 &buf[CIPSO_V4_HDR_LEN], 1811 buf_len - CIPSO_V4_HDR_LEN); 1812 break; 1813 case CIPSO_V4_TAG_ENUM: 1814 ret_val = cipso_v4_gentag_enum(doi_def, 1815 secattr, 1816 &buf[CIPSO_V4_HDR_LEN], 1817 buf_len - CIPSO_V4_HDR_LEN); 1818 break; 1819 case CIPSO_V4_TAG_RANGE: 1820 ret_val = cipso_v4_gentag_rng(doi_def, 1821 secattr, 1822 &buf[CIPSO_V4_HDR_LEN], 1823 buf_len - CIPSO_V4_HDR_LEN); 1824 break; 1825 case CIPSO_V4_TAG_LOCAL: 1826 ret_val = cipso_v4_gentag_loc(doi_def, 1827 secattr, 1828 &buf[CIPSO_V4_HDR_LEN], 1829 buf_len - CIPSO_V4_HDR_LEN); 1830 break; 1831 default: 1832 return -EPERM; 1833 } 1834 1835 iter++; 1836 } while (ret_val < 0 && 1837 iter < CIPSO_V4_TAG_MAXCNT && 1838 doi_def->tags[iter] != CIPSO_V4_TAG_INVALID); 1839 if (ret_val < 0) 1840 return ret_val; 1841 cipso_v4_gentag_hdr(doi_def, buf, ret_val); 1842 return CIPSO_V4_HDR_LEN + ret_val; 1843 } 1844 1845 /** 1846 * cipso_v4_sock_setattr - Add a CIPSO option to a socket 1847 * @sk: the socket 1848 * @doi_def: the CIPSO DOI to use 1849 * @secattr: the specific security attributes of the socket 1850 * 1851 * Description: 1852 * Set the CIPSO option on the given socket using the DOI definition and 1853 * security attributes passed to the function. This function requires 1854 * exclusive access to @sk, which means it either needs to be in the 1855 * process of being created or locked. Returns zero on success and negative 1856 * values on failure. 1857 * 1858 */ 1859 int cipso_v4_sock_setattr(struct sock *sk, 1860 const struct cipso_v4_doi *doi_def, 1861 const struct netlbl_lsm_secattr *secattr) 1862 { 1863 int ret_val = -EPERM; 1864 unsigned char *buf = NULL; 1865 u32 buf_len; 1866 u32 opt_len; 1867 struct ip_options_rcu *old, *opt = NULL; 1868 struct inet_sock *sk_inet; 1869 struct inet_connection_sock *sk_conn; 1870 1871 /* In the case of sock_create_lite(), the sock->sk field is not 1872 * defined yet but it is not a problem as the only users of these 1873 * "lite" PF_INET sockets are functions which do an accept() call 1874 * afterwards so we will label the socket as part of the accept(). */ 1875 if (sk == NULL) 1876 return 0; 1877 1878 /* We allocate the maximum CIPSO option size here so we are probably 1879 * being a little wasteful, but it makes our life _much_ easier later 1880 * on and after all we are only talking about 40 bytes. */ 1881 buf_len = CIPSO_V4_OPT_LEN_MAX; 1882 buf = kmalloc(buf_len, GFP_ATOMIC); 1883 if (buf == NULL) { 1884 ret_val = -ENOMEM; 1885 goto socket_setattr_failure; 1886 } 1887 1888 ret_val = cipso_v4_genopt(buf, buf_len, doi_def, secattr); 1889 if (ret_val < 0) 1890 goto socket_setattr_failure; 1891 buf_len = ret_val; 1892 1893 /* We can't use ip_options_get() directly because it makes a call to 1894 * ip_options_get_alloc() which allocates memory with GFP_KERNEL and 1895 * we won't always have CAP_NET_RAW even though we _always_ want to 1896 * set the IPOPT_CIPSO option. */ 1897 opt_len = (buf_len + 3) & ~3; 1898 opt = kzalloc(sizeof(*opt) + opt_len, GFP_ATOMIC); 1899 if (opt == NULL) { 1900 ret_val = -ENOMEM; 1901 goto socket_setattr_failure; 1902 } 1903 memcpy(opt->opt.__data, buf, buf_len); 1904 opt->opt.optlen = opt_len; 1905 opt->opt.cipso = sizeof(struct iphdr); 1906 kfree(buf); 1907 buf = NULL; 1908 1909 sk_inet = inet_sk(sk); 1910 1911 old = rcu_dereference_protected(sk_inet->inet_opt, sock_owned_by_user(sk)); 1912 if (sk_inet->is_icsk) { 1913 sk_conn = inet_csk(sk); 1914 if (old) 1915 sk_conn->icsk_ext_hdr_len -= old->opt.optlen; 1916 sk_conn->icsk_ext_hdr_len += opt->opt.optlen; 1917 sk_conn->icsk_sync_mss(sk, sk_conn->icsk_pmtu_cookie); 1918 } 1919 rcu_assign_pointer(sk_inet->inet_opt, opt); 1920 if (old) 1921 kfree_rcu(old, rcu); 1922 1923 return 0; 1924 1925 socket_setattr_failure: 1926 kfree(buf); 1927 kfree(opt); 1928 return ret_val; 1929 } 1930 1931 /** 1932 * cipso_v4_req_setattr - Add a CIPSO option to a connection request socket 1933 * @req: the connection request socket 1934 * @doi_def: the CIPSO DOI to use 1935 * @secattr: the specific security attributes of the socket 1936 * 1937 * Description: 1938 * Set the CIPSO option on the given socket using the DOI definition and 1939 * security attributes passed to the function. Returns zero on success and 1940 * negative values on failure. 1941 * 1942 */ 1943 int cipso_v4_req_setattr(struct request_sock *req, 1944 const struct cipso_v4_doi *doi_def, 1945 const struct netlbl_lsm_secattr *secattr) 1946 { 1947 int ret_val = -EPERM; 1948 unsigned char *buf = NULL; 1949 u32 buf_len; 1950 u32 opt_len; 1951 struct ip_options_rcu *opt = NULL; 1952 struct inet_request_sock *req_inet; 1953 1954 /* We allocate the maximum CIPSO option size here so we are probably 1955 * being a little wasteful, but it makes our life _much_ easier later 1956 * on and after all we are only talking about 40 bytes. */ 1957 buf_len = CIPSO_V4_OPT_LEN_MAX; 1958 buf = kmalloc(buf_len, GFP_ATOMIC); 1959 if (buf == NULL) { 1960 ret_val = -ENOMEM; 1961 goto req_setattr_failure; 1962 } 1963 1964 ret_val = cipso_v4_genopt(buf, buf_len, doi_def, secattr); 1965 if (ret_val < 0) 1966 goto req_setattr_failure; 1967 buf_len = ret_val; 1968 1969 /* We can't use ip_options_get() directly because it makes a call to 1970 * ip_options_get_alloc() which allocates memory with GFP_KERNEL and 1971 * we won't always have CAP_NET_RAW even though we _always_ want to 1972 * set the IPOPT_CIPSO option. */ 1973 opt_len = (buf_len + 3) & ~3; 1974 opt = kzalloc(sizeof(*opt) + opt_len, GFP_ATOMIC); 1975 if (opt == NULL) { 1976 ret_val = -ENOMEM; 1977 goto req_setattr_failure; 1978 } 1979 memcpy(opt->opt.__data, buf, buf_len); 1980 opt->opt.optlen = opt_len; 1981 opt->opt.cipso = sizeof(struct iphdr); 1982 kfree(buf); 1983 buf = NULL; 1984 1985 req_inet = inet_rsk(req); 1986 opt = xchg(&req_inet->opt, opt); 1987 if (opt) 1988 kfree_rcu(opt, rcu); 1989 1990 return 0; 1991 1992 req_setattr_failure: 1993 kfree(buf); 1994 kfree(opt); 1995 return ret_val; 1996 } 1997 1998 /** 1999 * cipso_v4_delopt - Delete the CIPSO option from a set of IP options 2000 * @opt_ptr: IP option pointer 2001 * 2002 * Description: 2003 * Deletes the CIPSO IP option from a set of IP options and makes the necessary 2004 * adjustments to the IP option structure. Returns zero on success, negative 2005 * values on failure. 2006 * 2007 */ 2008 static int cipso_v4_delopt(struct ip_options_rcu **opt_ptr) 2009 { 2010 int hdr_delta = 0; 2011 struct ip_options_rcu *opt = *opt_ptr; 2012 2013 if (opt->opt.srr || opt->opt.rr || opt->opt.ts || opt->opt.router_alert) { 2014 u8 cipso_len; 2015 u8 cipso_off; 2016 unsigned char *cipso_ptr; 2017 int iter; 2018 int optlen_new; 2019 2020 cipso_off = opt->opt.cipso - sizeof(struct iphdr); 2021 cipso_ptr = &opt->opt.__data[cipso_off]; 2022 cipso_len = cipso_ptr[1]; 2023 2024 if (opt->opt.srr > opt->opt.cipso) 2025 opt->opt.srr -= cipso_len; 2026 if (opt->opt.rr > opt->opt.cipso) 2027 opt->opt.rr -= cipso_len; 2028 if (opt->opt.ts > opt->opt.cipso) 2029 opt->opt.ts -= cipso_len; 2030 if (opt->opt.router_alert > opt->opt.cipso) 2031 opt->opt.router_alert -= cipso_len; 2032 opt->opt.cipso = 0; 2033 2034 memmove(cipso_ptr, cipso_ptr + cipso_len, 2035 opt->opt.optlen - cipso_off - cipso_len); 2036 2037 /* determining the new total option length is tricky because of 2038 * the padding necessary, the only thing i can think to do at 2039 * this point is walk the options one-by-one, skipping the 2040 * padding at the end to determine the actual option size and 2041 * from there we can determine the new total option length */ 2042 iter = 0; 2043 optlen_new = 0; 2044 while (iter < opt->opt.optlen) 2045 if (opt->opt.__data[iter] != IPOPT_NOP) { 2046 iter += opt->opt.__data[iter + 1]; 2047 optlen_new = iter; 2048 } else 2049 iter++; 2050 hdr_delta = opt->opt.optlen; 2051 opt->opt.optlen = (optlen_new + 3) & ~3; 2052 hdr_delta -= opt->opt.optlen; 2053 } else { 2054 /* only the cipso option was present on the socket so we can 2055 * remove the entire option struct */ 2056 *opt_ptr = NULL; 2057 hdr_delta = opt->opt.optlen; 2058 kfree_rcu(opt, rcu); 2059 } 2060 2061 return hdr_delta; 2062 } 2063 2064 /** 2065 * cipso_v4_sock_delattr - Delete the CIPSO option from a socket 2066 * @sk: the socket 2067 * 2068 * Description: 2069 * Removes the CIPSO option from a socket, if present. 2070 * 2071 */ 2072 void cipso_v4_sock_delattr(struct sock *sk) 2073 { 2074 int hdr_delta; 2075 struct ip_options_rcu *opt; 2076 struct inet_sock *sk_inet; 2077 2078 sk_inet = inet_sk(sk); 2079 opt = rcu_dereference_protected(sk_inet->inet_opt, 1); 2080 if (opt == NULL || opt->opt.cipso == 0) 2081 return; 2082 2083 hdr_delta = cipso_v4_delopt(&sk_inet->inet_opt); 2084 if (sk_inet->is_icsk && hdr_delta > 0) { 2085 struct inet_connection_sock *sk_conn = inet_csk(sk); 2086 sk_conn->icsk_ext_hdr_len -= hdr_delta; 2087 sk_conn->icsk_sync_mss(sk, sk_conn->icsk_pmtu_cookie); 2088 } 2089 } 2090 2091 /** 2092 * cipso_v4_req_delattr - Delete the CIPSO option from a request socket 2093 * @reg: the request socket 2094 * 2095 * Description: 2096 * Removes the CIPSO option from a request socket, if present. 2097 * 2098 */ 2099 void cipso_v4_req_delattr(struct request_sock *req) 2100 { 2101 struct ip_options_rcu *opt; 2102 struct inet_request_sock *req_inet; 2103 2104 req_inet = inet_rsk(req); 2105 opt = req_inet->opt; 2106 if (opt == NULL || opt->opt.cipso == 0) 2107 return; 2108 2109 cipso_v4_delopt(&req_inet->opt); 2110 } 2111 2112 /** 2113 * cipso_v4_getattr - Helper function for the cipso_v4_*_getattr functions 2114 * @cipso: the CIPSO v4 option 2115 * @secattr: the security attributes 2116 * 2117 * Description: 2118 * Inspect @cipso and return the security attributes in @secattr. Returns zero 2119 * on success and negative values on failure. 2120 * 2121 */ 2122 static int cipso_v4_getattr(const unsigned char *cipso, 2123 struct netlbl_lsm_secattr *secattr) 2124 { 2125 int ret_val = -ENOMSG; 2126 u32 doi; 2127 struct cipso_v4_doi *doi_def; 2128 2129 if (cipso_v4_cache_check(cipso, cipso[1], secattr) == 0) 2130 return 0; 2131 2132 doi = get_unaligned_be32(&cipso[2]); 2133 rcu_read_lock(); 2134 doi_def = cipso_v4_doi_search(doi); 2135 if (doi_def == NULL) 2136 goto getattr_return; 2137 /* XXX - This code assumes only one tag per CIPSO option which isn't 2138 * really a good assumption to make but since we only support the MAC 2139 * tags right now it is a safe assumption. */ 2140 switch (cipso[6]) { 2141 case CIPSO_V4_TAG_RBITMAP: 2142 ret_val = cipso_v4_parsetag_rbm(doi_def, &cipso[6], secattr); 2143 break; 2144 case CIPSO_V4_TAG_ENUM: 2145 ret_val = cipso_v4_parsetag_enum(doi_def, &cipso[6], secattr); 2146 break; 2147 case CIPSO_V4_TAG_RANGE: 2148 ret_val = cipso_v4_parsetag_rng(doi_def, &cipso[6], secattr); 2149 break; 2150 case CIPSO_V4_TAG_LOCAL: 2151 ret_val = cipso_v4_parsetag_loc(doi_def, &cipso[6], secattr); 2152 break; 2153 } 2154 if (ret_val == 0) 2155 secattr->type = NETLBL_NLTYPE_CIPSOV4; 2156 2157 getattr_return: 2158 rcu_read_unlock(); 2159 return ret_val; 2160 } 2161 2162 /** 2163 * cipso_v4_sock_getattr - Get the security attributes from a sock 2164 * @sk: the sock 2165 * @secattr: the security attributes 2166 * 2167 * Description: 2168 * Query @sk to see if there is a CIPSO option attached to the sock and if 2169 * there is return the CIPSO security attributes in @secattr. This function 2170 * requires that @sk be locked, or privately held, but it does not do any 2171 * locking itself. Returns zero on success and negative values on failure. 2172 * 2173 */ 2174 int cipso_v4_sock_getattr(struct sock *sk, struct netlbl_lsm_secattr *secattr) 2175 { 2176 struct ip_options_rcu *opt; 2177 int res = -ENOMSG; 2178 2179 rcu_read_lock(); 2180 opt = rcu_dereference(inet_sk(sk)->inet_opt); 2181 if (opt && opt->opt.cipso) 2182 res = cipso_v4_getattr(opt->opt.__data + 2183 opt->opt.cipso - 2184 sizeof(struct iphdr), 2185 secattr); 2186 rcu_read_unlock(); 2187 return res; 2188 } 2189 2190 /** 2191 * cipso_v4_skbuff_setattr - Set the CIPSO option on a packet 2192 * @skb: the packet 2193 * @secattr: the security attributes 2194 * 2195 * Description: 2196 * Set the CIPSO option on the given packet based on the security attributes. 2197 * Returns a pointer to the IP header on success and NULL on failure. 2198 * 2199 */ 2200 int cipso_v4_skbuff_setattr(struct sk_buff *skb, 2201 const struct cipso_v4_doi *doi_def, 2202 const struct netlbl_lsm_secattr *secattr) 2203 { 2204 int ret_val; 2205 struct iphdr *iph; 2206 struct ip_options *opt = &IPCB(skb)->opt; 2207 unsigned char buf[CIPSO_V4_OPT_LEN_MAX]; 2208 u32 buf_len = CIPSO_V4_OPT_LEN_MAX; 2209 u32 opt_len; 2210 int len_delta; 2211 2212 ret_val = cipso_v4_genopt(buf, buf_len, doi_def, secattr); 2213 if (ret_val < 0) 2214 return ret_val; 2215 buf_len = ret_val; 2216 opt_len = (buf_len + 3) & ~3; 2217 2218 /* we overwrite any existing options to ensure that we have enough 2219 * room for the CIPSO option, the reason is that we _need_ to guarantee 2220 * that the security label is applied to the packet - we do the same 2221 * thing when using the socket options and it hasn't caused a problem, 2222 * if we need to we can always revisit this choice later */ 2223 2224 len_delta = opt_len - opt->optlen; 2225 /* if we don't ensure enough headroom we could panic on the skb_push() 2226 * call below so make sure we have enough, we are also "mangling" the 2227 * packet so we should probably do a copy-on-write call anyway */ 2228 ret_val = skb_cow(skb, skb_headroom(skb) + len_delta); 2229 if (ret_val < 0) 2230 return ret_val; 2231 2232 if (len_delta > 0) { 2233 /* we assume that the header + opt->optlen have already been 2234 * "pushed" in ip_options_build() or similar */ 2235 iph = ip_hdr(skb); 2236 skb_push(skb, len_delta); 2237 memmove((char *)iph - len_delta, iph, iph->ihl << 2); 2238 skb_reset_network_header(skb); 2239 iph = ip_hdr(skb); 2240 } else if (len_delta < 0) { 2241 iph = ip_hdr(skb); 2242 memset(iph + 1, IPOPT_NOP, opt->optlen); 2243 } else 2244 iph = ip_hdr(skb); 2245 2246 if (opt->optlen > 0) 2247 memset(opt, 0, sizeof(*opt)); 2248 opt->optlen = opt_len; 2249 opt->cipso = sizeof(struct iphdr); 2250 opt->is_changed = 1; 2251 2252 /* we have to do the following because we are being called from a 2253 * netfilter hook which means the packet already has had the header 2254 * fields populated and the checksum calculated - yes this means we 2255 * are doing more work than needed but we do it to keep the core 2256 * stack clean and tidy */ 2257 memcpy(iph + 1, buf, buf_len); 2258 if (opt_len > buf_len) 2259 memset((char *)(iph + 1) + buf_len, 0, opt_len - buf_len); 2260 if (len_delta != 0) { 2261 iph->ihl = 5 + (opt_len >> 2); 2262 iph->tot_len = htons(skb->len); 2263 } 2264 ip_send_check(iph); 2265 2266 return 0; 2267 } 2268 2269 /** 2270 * cipso_v4_skbuff_delattr - Delete any CIPSO options from a packet 2271 * @skb: the packet 2272 * 2273 * Description: 2274 * Removes any and all CIPSO options from the given packet. Returns zero on 2275 * success, negative values on failure. 2276 * 2277 */ 2278 int cipso_v4_skbuff_delattr(struct sk_buff *skb) 2279 { 2280 int ret_val; 2281 struct iphdr *iph; 2282 struct ip_options *opt = &IPCB(skb)->opt; 2283 unsigned char *cipso_ptr; 2284 2285 if (opt->cipso == 0) 2286 return 0; 2287 2288 /* since we are changing the packet we should make a copy */ 2289 ret_val = skb_cow(skb, skb_headroom(skb)); 2290 if (ret_val < 0) 2291 return ret_val; 2292 2293 /* the easiest thing to do is just replace the cipso option with noop 2294 * options since we don't change the size of the packet, although we 2295 * still need to recalculate the checksum */ 2296 2297 iph = ip_hdr(skb); 2298 cipso_ptr = (unsigned char *)iph + opt->cipso; 2299 memset(cipso_ptr, IPOPT_NOOP, cipso_ptr[1]); 2300 opt->cipso = 0; 2301 opt->is_changed = 1; 2302 2303 ip_send_check(iph); 2304 2305 return 0; 2306 } 2307 2308 /** 2309 * cipso_v4_skbuff_getattr - Get the security attributes from the CIPSO option 2310 * @skb: the packet 2311 * @secattr: the security attributes 2312 * 2313 * Description: 2314 * Parse the given packet's CIPSO option and return the security attributes. 2315 * Returns zero on success and negative values on failure. 2316 * 2317 */ 2318 int cipso_v4_skbuff_getattr(const struct sk_buff *skb, 2319 struct netlbl_lsm_secattr *secattr) 2320 { 2321 return cipso_v4_getattr(CIPSO_V4_OPTPTR(skb), secattr); 2322 } 2323 2324 /* 2325 * Setup Functions 2326 */ 2327 2328 /** 2329 * cipso_v4_init - Initialize the CIPSO module 2330 * 2331 * Description: 2332 * Initialize the CIPSO module and prepare it for use. Returns zero on success 2333 * and negative values on failure. 2334 * 2335 */ 2336 static int __init cipso_v4_init(void) 2337 { 2338 int ret_val; 2339 2340 ret_val = cipso_v4_cache_init(); 2341 if (ret_val != 0) 2342 panic("Failed to initialize the CIPSO/IPv4 cache (%d)\n", 2343 ret_val); 2344 2345 return 0; 2346 } 2347 2348 subsys_initcall(cipso_v4_init); 2349