1/* SCTP kernel implementation 2 * (C) Copyright 2007 Hewlett-Packard Development Company, L.P. 3 * 4 * This file is part of the SCTP kernel implementation 5 * 6 * This SCTP implementation is free software; 7 * you can redistribute it and/or modify it under the terms of 8 * the GNU General Public License as published by 9 * the Free Software Foundation; either version 2, or (at your option) 10 * any later version. 11 * 12 * This SCTP implementation is distributed in the hope that it 13 * will be useful, but WITHOUT ANY WARRANTY; without even the implied 14 * ************************ 15 * warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. 16 * See the GNU General Public License for more details. 17 * 18 * You should have received a copy of the GNU General Public License 19 * along with GNU CC; see the file COPYING. If not, see 20 * <http://www.gnu.org/licenses/>. 21 * 22 * Please send any bug reports or fixes you make to the 23 * email address(es): 24 * lksctp developers <linux-sctp@vger.kernel.org> 25 * 26 * Written or modified by: 27 * Vlad Yasevich <vladislav.yasevich@hp.com> 28 */ 29 30#include <linux/slab.h> 31#include <linux/types.h> 32#include <linux/crypto.h> 33#include <linux/scatterlist.h> 34#include <net/sctp/sctp.h> 35#include <net/sctp/auth.h> 36 37static struct sctp_hmac sctp_hmac_list[SCTP_AUTH_NUM_HMACS] = { 38 { 39 /* id 0 is reserved. as all 0 */ 40 .hmac_id = SCTP_AUTH_HMAC_ID_RESERVED_0, 41 }, 42 { 43 .hmac_id = SCTP_AUTH_HMAC_ID_SHA1, 44 .hmac_name = "hmac(sha1)", 45 .hmac_len = SCTP_SHA1_SIG_SIZE, 46 }, 47 { 48 /* id 2 is reserved as well */ 49 .hmac_id = SCTP_AUTH_HMAC_ID_RESERVED_2, 50 }, 51#if defined (CONFIG_CRYPTO_SHA256) || defined (CONFIG_CRYPTO_SHA256_MODULE) 52 { 53 .hmac_id = SCTP_AUTH_HMAC_ID_SHA256, 54 .hmac_name = "hmac(sha256)", 55 .hmac_len = SCTP_SHA256_SIG_SIZE, 56 } 57#endif 58}; 59 60 61void sctp_auth_key_put(struct sctp_auth_bytes *key) 62{ 63 if (!key) 64 return; 65 66 if (atomic_dec_and_test(&key->refcnt)) { 67 kzfree(key); 68 SCTP_DBG_OBJCNT_DEC(keys); 69 } 70} 71 72/* Create a new key structure of a given length */ 73static struct sctp_auth_bytes *sctp_auth_create_key(__u32 key_len, gfp_t gfp) 74{ 75 struct sctp_auth_bytes *key; 76 77 /* Verify that we are not going to overflow INT_MAX */ 78 if (key_len > (INT_MAX - sizeof(struct sctp_auth_bytes))) 79 return NULL; 80 81 /* Allocate the shared key */ 82 key = kmalloc(sizeof(struct sctp_auth_bytes) + key_len, gfp); 83 if (!key) 84 return NULL; 85 86 key->len = key_len; 87 atomic_set(&key->refcnt, 1); 88 SCTP_DBG_OBJCNT_INC(keys); 89 90 return key; 91} 92 93/* Create a new shared key container with a give key id */ 94struct sctp_shared_key *sctp_auth_shkey_create(__u16 key_id, gfp_t gfp) 95{ 96 struct sctp_shared_key *new; 97 98 /* Allocate the shared key container */ 99 new = kzalloc(sizeof(struct sctp_shared_key), gfp); 100 if (!new) 101 return NULL; 102 103 INIT_LIST_HEAD(&new->key_list); 104 new->key_id = key_id; 105 106 return new; 107} 108 109/* Free the shared key structure */ 110static void sctp_auth_shkey_free(struct sctp_shared_key *sh_key) 111{ 112 BUG_ON(!list_empty(&sh_key->key_list)); 113 sctp_auth_key_put(sh_key->key); 114 sh_key->key = NULL; 115 kfree(sh_key); 116} 117 118/* Destroy the entire key list. This is done during the 119 * associon and endpoint free process. 120 */ 121void sctp_auth_destroy_keys(struct list_head *keys) 122{ 123 struct sctp_shared_key *ep_key; 124 struct sctp_shared_key *tmp; 125 126 if (list_empty(keys)) 127 return; 128 129 key_for_each_safe(ep_key, tmp, keys) { 130 list_del_init(&ep_key->key_list); 131 sctp_auth_shkey_free(ep_key); 132 } 133} 134 135/* Compare two byte vectors as numbers. Return values 136 * are: 137 * 0 - vectors are equal 138 * < 0 - vector 1 is smaller than vector2 139 * > 0 - vector 1 is greater than vector2 140 * 141 * Algorithm is: 142 * This is performed by selecting the numerically smaller key vector... 143 * If the key vectors are equal as numbers but differ in length ... 144 * the shorter vector is considered smaller 145 * 146 * Examples (with small values): 147 * 000123456789 > 123456789 (first number is longer) 148 * 000123456789 < 234567891 (second number is larger numerically) 149 * 123456789 > 2345678 (first number is both larger & longer) 150 */ 151static int sctp_auth_compare_vectors(struct sctp_auth_bytes *vector1, 152 struct sctp_auth_bytes *vector2) 153{ 154 int diff; 155 int i; 156 const __u8 *longer; 157 158 diff = vector1->len - vector2->len; 159 if (diff) { 160 longer = (diff > 0) ? vector1->data : vector2->data; 161 162 /* Check to see if the longer number is 163 * lead-zero padded. If it is not, it 164 * is automatically larger numerically. 165 */ 166 for (i = 0; i < abs(diff); i++) { 167 if (longer[i] != 0) 168 return diff; 169 } 170 } 171 172 /* lengths are the same, compare numbers */ 173 return memcmp(vector1->data, vector2->data, vector1->len); 174} 175 176/* 177 * Create a key vector as described in SCTP-AUTH, Section 6.1 178 * The RANDOM parameter, the CHUNKS parameter and the HMAC-ALGO 179 * parameter sent by each endpoint are concatenated as byte vectors. 180 * These parameters include the parameter type, parameter length, and 181 * the parameter value, but padding is omitted; all padding MUST be 182 * removed from this concatenation before proceeding with further 183 * computation of keys. Parameters which were not sent are simply 184 * omitted from the concatenation process. The resulting two vectors 185 * are called the two key vectors. 186 */ 187static struct sctp_auth_bytes *sctp_auth_make_key_vector( 188 sctp_random_param_t *random, 189 sctp_chunks_param_t *chunks, 190 sctp_hmac_algo_param_t *hmacs, 191 gfp_t gfp) 192{ 193 struct sctp_auth_bytes *new; 194 __u32 len; 195 __u32 offset = 0; 196 __u16 random_len, hmacs_len, chunks_len = 0; 197 198 random_len = ntohs(random->param_hdr.length); 199 hmacs_len = ntohs(hmacs->param_hdr.length); 200 if (chunks) 201 chunks_len = ntohs(chunks->param_hdr.length); 202 203 len = random_len + hmacs_len + chunks_len; 204 205 new = sctp_auth_create_key(len, gfp); 206 if (!new) 207 return NULL; 208 209 memcpy(new->data, random, random_len); 210 offset += random_len; 211 212 if (chunks) { 213 memcpy(new->data + offset, chunks, chunks_len); 214 offset += chunks_len; 215 } 216 217 memcpy(new->data + offset, hmacs, hmacs_len); 218 219 return new; 220} 221 222 223/* Make a key vector based on our local parameters */ 224static struct sctp_auth_bytes *sctp_auth_make_local_vector( 225 const struct sctp_association *asoc, 226 gfp_t gfp) 227{ 228 return sctp_auth_make_key_vector( 229 (sctp_random_param_t *)asoc->c.auth_random, 230 (sctp_chunks_param_t *)asoc->c.auth_chunks, 231 (sctp_hmac_algo_param_t *)asoc->c.auth_hmacs, 232 gfp); 233} 234 235/* Make a key vector based on peer's parameters */ 236static struct sctp_auth_bytes *sctp_auth_make_peer_vector( 237 const struct sctp_association *asoc, 238 gfp_t gfp) 239{ 240 return sctp_auth_make_key_vector(asoc->peer.peer_random, 241 asoc->peer.peer_chunks, 242 asoc->peer.peer_hmacs, 243 gfp); 244} 245 246 247/* Set the value of the association shared key base on the parameters 248 * given. The algorithm is: 249 * From the endpoint pair shared keys and the key vectors the 250 * association shared keys are computed. This is performed by selecting 251 * the numerically smaller key vector and concatenating it to the 252 * endpoint pair shared key, and then concatenating the numerically 253 * larger key vector to that. The result of the concatenation is the 254 * association shared key. 255 */ 256static struct sctp_auth_bytes *sctp_auth_asoc_set_secret( 257 struct sctp_shared_key *ep_key, 258 struct sctp_auth_bytes *first_vector, 259 struct sctp_auth_bytes *last_vector, 260 gfp_t gfp) 261{ 262 struct sctp_auth_bytes *secret; 263 __u32 offset = 0; 264 __u32 auth_len; 265 266 auth_len = first_vector->len + last_vector->len; 267 if (ep_key->key) 268 auth_len += ep_key->key->len; 269 270 secret = sctp_auth_create_key(auth_len, gfp); 271 if (!secret) 272 return NULL; 273 274 if (ep_key->key) { 275 memcpy(secret->data, ep_key->key->data, ep_key->key->len); 276 offset += ep_key->key->len; 277 } 278 279 memcpy(secret->data + offset, first_vector->data, first_vector->len); 280 offset += first_vector->len; 281 282 memcpy(secret->data + offset, last_vector->data, last_vector->len); 283 284 return secret; 285} 286 287/* Create an association shared key. Follow the algorithm 288 * described in SCTP-AUTH, Section 6.1 289 */ 290static struct sctp_auth_bytes *sctp_auth_asoc_create_secret( 291 const struct sctp_association *asoc, 292 struct sctp_shared_key *ep_key, 293 gfp_t gfp) 294{ 295 struct sctp_auth_bytes *local_key_vector; 296 struct sctp_auth_bytes *peer_key_vector; 297 struct sctp_auth_bytes *first_vector, 298 *last_vector; 299 struct sctp_auth_bytes *secret = NULL; 300 int cmp; 301 302 303 /* Now we need to build the key vectors 304 * SCTP-AUTH , Section 6.1 305 * The RANDOM parameter, the CHUNKS parameter and the HMAC-ALGO 306 * parameter sent by each endpoint are concatenated as byte vectors. 307 * These parameters include the parameter type, parameter length, and 308 * the parameter value, but padding is omitted; all padding MUST be 309 * removed from this concatenation before proceeding with further 310 * computation of keys. Parameters which were not sent are simply 311 * omitted from the concatenation process. The resulting two vectors 312 * are called the two key vectors. 313 */ 314 315 local_key_vector = sctp_auth_make_local_vector(asoc, gfp); 316 peer_key_vector = sctp_auth_make_peer_vector(asoc, gfp); 317 318 if (!peer_key_vector || !local_key_vector) 319 goto out; 320 321 /* Figure out the order in which the key_vectors will be 322 * added to the endpoint shared key. 323 * SCTP-AUTH, Section 6.1: 324 * This is performed by selecting the numerically smaller key 325 * vector and concatenating it to the endpoint pair shared 326 * key, and then concatenating the numerically larger key 327 * vector to that. If the key vectors are equal as numbers 328 * but differ in length, then the concatenation order is the 329 * endpoint shared key, followed by the shorter key vector, 330 * followed by the longer key vector. Otherwise, the key 331 * vectors are identical, and may be concatenated to the 332 * endpoint pair key in any order. 333 */ 334 cmp = sctp_auth_compare_vectors(local_key_vector, 335 peer_key_vector); 336 if (cmp < 0) { 337 first_vector = local_key_vector; 338 last_vector = peer_key_vector; 339 } else { 340 first_vector = peer_key_vector; 341 last_vector = local_key_vector; 342 } 343 344 secret = sctp_auth_asoc_set_secret(ep_key, first_vector, last_vector, 345 gfp); 346out: 347 sctp_auth_key_put(local_key_vector); 348 sctp_auth_key_put(peer_key_vector); 349 350 return secret; 351} 352 353/* 354 * Populate the association overlay list with the list 355 * from the endpoint. 356 */ 357int sctp_auth_asoc_copy_shkeys(const struct sctp_endpoint *ep, 358 struct sctp_association *asoc, 359 gfp_t gfp) 360{ 361 struct sctp_shared_key *sh_key; 362 struct sctp_shared_key *new; 363 364 BUG_ON(!list_empty(&asoc->endpoint_shared_keys)); 365 366 key_for_each(sh_key, &ep->endpoint_shared_keys) { 367 new = sctp_auth_shkey_create(sh_key->key_id, gfp); 368 if (!new) 369 goto nomem; 370 371 new->key = sh_key->key; 372 sctp_auth_key_hold(new->key); 373 list_add(&new->key_list, &asoc->endpoint_shared_keys); 374 } 375 376 return 0; 377 378nomem: 379 sctp_auth_destroy_keys(&asoc->endpoint_shared_keys); 380 return -ENOMEM; 381} 382 383 384/* Public interface to creat the association shared key. 385 * See code above for the algorithm. 386 */ 387int sctp_auth_asoc_init_active_key(struct sctp_association *asoc, gfp_t gfp) 388{ 389 struct sctp_auth_bytes *secret; 390 struct sctp_shared_key *ep_key; 391 392 /* If we don't support AUTH, or peer is not capable 393 * we don't need to do anything. 394 */ 395 if (!asoc->ep->auth_enable || !asoc->peer.auth_capable) 396 return 0; 397 398 /* If the key_id is non-zero and we couldn't find an 399 * endpoint pair shared key, we can't compute the 400 * secret. 401 * For key_id 0, endpoint pair shared key is a NULL key. 402 */ 403 ep_key = sctp_auth_get_shkey(asoc, asoc->active_key_id); 404 BUG_ON(!ep_key); 405 406 secret = sctp_auth_asoc_create_secret(asoc, ep_key, gfp); 407 if (!secret) 408 return -ENOMEM; 409 410 sctp_auth_key_put(asoc->asoc_shared_key); 411 asoc->asoc_shared_key = secret; 412 413 return 0; 414} 415 416 417/* Find the endpoint pair shared key based on the key_id */ 418struct sctp_shared_key *sctp_auth_get_shkey( 419 const struct sctp_association *asoc, 420 __u16 key_id) 421{ 422 struct sctp_shared_key *key; 423 424 /* First search associations set of endpoint pair shared keys */ 425 key_for_each(key, &asoc->endpoint_shared_keys) { 426 if (key->key_id == key_id) 427 return key; 428 } 429 430 return NULL; 431} 432 433/* 434 * Initialize all the possible digest transforms that we can use. Right now 435 * now, the supported digests are SHA1 and SHA256. We do this here once 436 * because of the restrictiong that transforms may only be allocated in 437 * user context. This forces us to pre-allocated all possible transforms 438 * at the endpoint init time. 439 */ 440int sctp_auth_init_hmacs(struct sctp_endpoint *ep, gfp_t gfp) 441{ 442 struct crypto_hash *tfm = NULL; 443 __u16 id; 444 445 /* If AUTH extension is disabled, we are done */ 446 if (!ep->auth_enable) { 447 ep->auth_hmacs = NULL; 448 return 0; 449 } 450 451 /* If the transforms are already allocated, we are done */ 452 if (ep->auth_hmacs) 453 return 0; 454 455 /* Allocated the array of pointers to transorms */ 456 ep->auth_hmacs = kzalloc( 457 sizeof(struct crypto_hash *) * SCTP_AUTH_NUM_HMACS, 458 gfp); 459 if (!ep->auth_hmacs) 460 return -ENOMEM; 461 462 for (id = 0; id < SCTP_AUTH_NUM_HMACS; id++) { 463 464 /* See is we support the id. Supported IDs have name and 465 * length fields set, so that we can allocated and use 466 * them. We can safely just check for name, for without the 467 * name, we can't allocate the TFM. 468 */ 469 if (!sctp_hmac_list[id].hmac_name) 470 continue; 471 472 /* If this TFM has been allocated, we are all set */ 473 if (ep->auth_hmacs[id]) 474 continue; 475 476 /* Allocate the ID */ 477 tfm = crypto_alloc_hash(sctp_hmac_list[id].hmac_name, 0, 478 CRYPTO_ALG_ASYNC); 479 if (IS_ERR(tfm)) 480 goto out_err; 481 482 ep->auth_hmacs[id] = tfm; 483 } 484 485 return 0; 486 487out_err: 488 /* Clean up any successful allocations */ 489 sctp_auth_destroy_hmacs(ep->auth_hmacs); 490 return -ENOMEM; 491} 492 493/* Destroy the hmac tfm array */ 494void sctp_auth_destroy_hmacs(struct crypto_hash *auth_hmacs[]) 495{ 496 int i; 497 498 if (!auth_hmacs) 499 return; 500 501 for (i = 0; i < SCTP_AUTH_NUM_HMACS; i++) { 502 if (auth_hmacs[i]) 503 crypto_free_hash(auth_hmacs[i]); 504 } 505 kfree(auth_hmacs); 506} 507 508 509struct sctp_hmac *sctp_auth_get_hmac(__u16 hmac_id) 510{ 511 return &sctp_hmac_list[hmac_id]; 512} 513 514/* Get an hmac description information that we can use to build 515 * the AUTH chunk 516 */ 517struct sctp_hmac *sctp_auth_asoc_get_hmac(const struct sctp_association *asoc) 518{ 519 struct sctp_hmac_algo_param *hmacs; 520 __u16 n_elt; 521 __u16 id = 0; 522 int i; 523 524 /* If we have a default entry, use it */ 525 if (asoc->default_hmac_id) 526 return &sctp_hmac_list[asoc->default_hmac_id]; 527 528 /* Since we do not have a default entry, find the first entry 529 * we support and return that. Do not cache that id. 530 */ 531 hmacs = asoc->peer.peer_hmacs; 532 if (!hmacs) 533 return NULL; 534 535 n_elt = (ntohs(hmacs->param_hdr.length) - sizeof(sctp_paramhdr_t)) >> 1; 536 for (i = 0; i < n_elt; i++) { 537 id = ntohs(hmacs->hmac_ids[i]); 538 539 /* Check the id is in the supported range. And 540 * see if we support the id. Supported IDs have name and 541 * length fields set, so that we can allocate and use 542 * them. We can safely just check for name, for without the 543 * name, we can't allocate the TFM. 544 */ 545 if (id > SCTP_AUTH_HMAC_ID_MAX || 546 !sctp_hmac_list[id].hmac_name) { 547 id = 0; 548 continue; 549 } 550 551 break; 552 } 553 554 if (id == 0) 555 return NULL; 556 557 return &sctp_hmac_list[id]; 558} 559 560static int __sctp_auth_find_hmacid(__be16 *hmacs, int n_elts, __be16 hmac_id) 561{ 562 int found = 0; 563 int i; 564 565 for (i = 0; i < n_elts; i++) { 566 if (hmac_id == hmacs[i]) { 567 found = 1; 568 break; 569 } 570 } 571 572 return found; 573} 574 575/* See if the HMAC_ID is one that we claim as supported */ 576int sctp_auth_asoc_verify_hmac_id(const struct sctp_association *asoc, 577 __be16 hmac_id) 578{ 579 struct sctp_hmac_algo_param *hmacs; 580 __u16 n_elt; 581 582 if (!asoc) 583 return 0; 584 585 hmacs = (struct sctp_hmac_algo_param *)asoc->c.auth_hmacs; 586 n_elt = (ntohs(hmacs->param_hdr.length) - sizeof(sctp_paramhdr_t)) >> 1; 587 588 return __sctp_auth_find_hmacid(hmacs->hmac_ids, n_elt, hmac_id); 589} 590 591 592/* Cache the default HMAC id. This to follow this text from SCTP-AUTH: 593 * Section 6.1: 594 * The receiver of a HMAC-ALGO parameter SHOULD use the first listed 595 * algorithm it supports. 596 */ 597void sctp_auth_asoc_set_default_hmac(struct sctp_association *asoc, 598 struct sctp_hmac_algo_param *hmacs) 599{ 600 struct sctp_endpoint *ep; 601 __u16 id; 602 int i; 603 int n_params; 604 605 /* if the default id is already set, use it */ 606 if (asoc->default_hmac_id) 607 return; 608 609 n_params = (ntohs(hmacs->param_hdr.length) 610 - sizeof(sctp_paramhdr_t)) >> 1; 611 ep = asoc->ep; 612 for (i = 0; i < n_params; i++) { 613 id = ntohs(hmacs->hmac_ids[i]); 614 615 /* Check the id is in the supported range */ 616 if (id > SCTP_AUTH_HMAC_ID_MAX) 617 continue; 618 619 /* If this TFM has been allocated, use this id */ 620 if (ep->auth_hmacs[id]) { 621 asoc->default_hmac_id = id; 622 break; 623 } 624 } 625} 626 627 628/* Check to see if the given chunk is supposed to be authenticated */ 629static int __sctp_auth_cid(sctp_cid_t chunk, struct sctp_chunks_param *param) 630{ 631 unsigned short len; 632 int found = 0; 633 int i; 634 635 if (!param || param->param_hdr.length == 0) 636 return 0; 637 638 len = ntohs(param->param_hdr.length) - sizeof(sctp_paramhdr_t); 639 640 /* SCTP-AUTH, Section 3.2 641 * The chunk types for INIT, INIT-ACK, SHUTDOWN-COMPLETE and AUTH 642 * chunks MUST NOT be listed in the CHUNKS parameter. However, if 643 * a CHUNKS parameter is received then the types for INIT, INIT-ACK, 644 * SHUTDOWN-COMPLETE and AUTH chunks MUST be ignored. 645 */ 646 for (i = 0; !found && i < len; i++) { 647 switch (param->chunks[i]) { 648 case SCTP_CID_INIT: 649 case SCTP_CID_INIT_ACK: 650 case SCTP_CID_SHUTDOWN_COMPLETE: 651 case SCTP_CID_AUTH: 652 break; 653 654 default: 655 if (param->chunks[i] == chunk) 656 found = 1; 657 break; 658 } 659 } 660 661 return found; 662} 663 664/* Check if peer requested that this chunk is authenticated */ 665int sctp_auth_send_cid(sctp_cid_t chunk, const struct sctp_association *asoc) 666{ 667 if (!asoc) 668 return 0; 669 670 if (!asoc->ep->auth_enable || !asoc->peer.auth_capable) 671 return 0; 672 673 return __sctp_auth_cid(chunk, asoc->peer.peer_chunks); 674} 675 676/* Check if we requested that peer authenticate this chunk. */ 677int sctp_auth_recv_cid(sctp_cid_t chunk, const struct sctp_association *asoc) 678{ 679 if (!asoc) 680 return 0; 681 682 if (!asoc->ep->auth_enable) 683 return 0; 684 685 return __sctp_auth_cid(chunk, 686 (struct sctp_chunks_param *)asoc->c.auth_chunks); 687} 688 689/* SCTP-AUTH: Section 6.2: 690 * The sender MUST calculate the MAC as described in RFC2104 [2] using 691 * the hash function H as described by the MAC Identifier and the shared 692 * association key K based on the endpoint pair shared key described by 693 * the shared key identifier. The 'data' used for the computation of 694 * the AUTH-chunk is given by the AUTH chunk with its HMAC field set to 695 * zero (as shown in Figure 6) followed by all chunks that are placed 696 * after the AUTH chunk in the SCTP packet. 697 */ 698void sctp_auth_calculate_hmac(const struct sctp_association *asoc, 699 struct sk_buff *skb, 700 struct sctp_auth_chunk *auth, 701 gfp_t gfp) 702{ 703 struct scatterlist sg; 704 struct hash_desc desc; 705 struct sctp_auth_bytes *asoc_key; 706 __u16 key_id, hmac_id; 707 __u8 *digest; 708 unsigned char *end; 709 int free_key = 0; 710 711 /* Extract the info we need: 712 * - hmac id 713 * - key id 714 */ 715 key_id = ntohs(auth->auth_hdr.shkey_id); 716 hmac_id = ntohs(auth->auth_hdr.hmac_id); 717 718 if (key_id == asoc->active_key_id) 719 asoc_key = asoc->asoc_shared_key; 720 else { 721 struct sctp_shared_key *ep_key; 722 723 ep_key = sctp_auth_get_shkey(asoc, key_id); 724 if (!ep_key) 725 return; 726 727 asoc_key = sctp_auth_asoc_create_secret(asoc, ep_key, gfp); 728 if (!asoc_key) 729 return; 730 731 free_key = 1; 732 } 733 734 /* set up scatter list */ 735 end = skb_tail_pointer(skb); 736 sg_init_one(&sg, auth, end - (unsigned char *)auth); 737 738 desc.tfm = asoc->ep->auth_hmacs[hmac_id]; 739 desc.flags = 0; 740 741 digest = auth->auth_hdr.hmac; 742 if (crypto_hash_setkey(desc.tfm, &asoc_key->data[0], asoc_key->len)) 743 goto free; 744 745 crypto_hash_digest(&desc, &sg, sg.length, digest); 746 747free: 748 if (free_key) 749 sctp_auth_key_put(asoc_key); 750} 751 752/* API Helpers */ 753 754/* Add a chunk to the endpoint authenticated chunk list */ 755int sctp_auth_ep_add_chunkid(struct sctp_endpoint *ep, __u8 chunk_id) 756{ 757 struct sctp_chunks_param *p = ep->auth_chunk_list; 758 __u16 nchunks; 759 __u16 param_len; 760 761 /* If this chunk is already specified, we are done */ 762 if (__sctp_auth_cid(chunk_id, p)) 763 return 0; 764 765 /* Check if we can add this chunk to the array */ 766 param_len = ntohs(p->param_hdr.length); 767 nchunks = param_len - sizeof(sctp_paramhdr_t); 768 if (nchunks == SCTP_NUM_CHUNK_TYPES) 769 return -EINVAL; 770 771 p->chunks[nchunks] = chunk_id; 772 p->param_hdr.length = htons(param_len + 1); 773 return 0; 774} 775 776/* Add hmac identifires to the endpoint list of supported hmac ids */ 777int sctp_auth_ep_set_hmacs(struct sctp_endpoint *ep, 778 struct sctp_hmacalgo *hmacs) 779{ 780 int has_sha1 = 0; 781 __u16 id; 782 int i; 783 784 /* Scan the list looking for unsupported id. Also make sure that 785 * SHA1 is specified. 786 */ 787 for (i = 0; i < hmacs->shmac_num_idents; i++) { 788 id = hmacs->shmac_idents[i]; 789 790 if (id > SCTP_AUTH_HMAC_ID_MAX) 791 return -EOPNOTSUPP; 792 793 if (SCTP_AUTH_HMAC_ID_SHA1 == id) 794 has_sha1 = 1; 795 796 if (!sctp_hmac_list[id].hmac_name) 797 return -EOPNOTSUPP; 798 } 799 800 if (!has_sha1) 801 return -EINVAL; 802 803 memcpy(ep->auth_hmacs_list->hmac_ids, &hmacs->shmac_idents[0], 804 hmacs->shmac_num_idents * sizeof(__u16)); 805 ep->auth_hmacs_list->param_hdr.length = htons(sizeof(sctp_paramhdr_t) + 806 hmacs->shmac_num_idents * sizeof(__u16)); 807 return 0; 808} 809 810/* Set a new shared key on either endpoint or association. If the 811 * the key with a same ID already exists, replace the key (remove the 812 * old key and add a new one). 813 */ 814int sctp_auth_set_key(struct sctp_endpoint *ep, 815 struct sctp_association *asoc, 816 struct sctp_authkey *auth_key) 817{ 818 struct sctp_shared_key *cur_key = NULL; 819 struct sctp_auth_bytes *key; 820 struct list_head *sh_keys; 821 int replace = 0; 822 823 /* Try to find the given key id to see if 824 * we are doing a replace, or adding a new key 825 */ 826 if (asoc) 827 sh_keys = &asoc->endpoint_shared_keys; 828 else 829 sh_keys = &ep->endpoint_shared_keys; 830 831 key_for_each(cur_key, sh_keys) { 832 if (cur_key->key_id == auth_key->sca_keynumber) { 833 replace = 1; 834 break; 835 } 836 } 837 838 /* If we are not replacing a key id, we need to allocate 839 * a shared key. 840 */ 841 if (!replace) { 842 cur_key = sctp_auth_shkey_create(auth_key->sca_keynumber, 843 GFP_KERNEL); 844 if (!cur_key) 845 return -ENOMEM; 846 } 847 848 /* Create a new key data based on the info passed in */ 849 key = sctp_auth_create_key(auth_key->sca_keylength, GFP_KERNEL); 850 if (!key) 851 goto nomem; 852 853 memcpy(key->data, &auth_key->sca_key[0], auth_key->sca_keylength); 854 855 /* If we are replacing, remove the old keys data from the 856 * key id. If we are adding new key id, add it to the 857 * list. 858 */ 859 if (replace) 860 sctp_auth_key_put(cur_key->key); 861 else 862 list_add(&cur_key->key_list, sh_keys); 863 864 cur_key->key = key; 865 return 0; 866nomem: 867 if (!replace) 868 sctp_auth_shkey_free(cur_key); 869 870 return -ENOMEM; 871} 872 873int sctp_auth_set_active_key(struct sctp_endpoint *ep, 874 struct sctp_association *asoc, 875 __u16 key_id) 876{ 877 struct sctp_shared_key *key; 878 struct list_head *sh_keys; 879 int found = 0; 880 881 /* The key identifier MUST correst to an existing key */ 882 if (asoc) 883 sh_keys = &asoc->endpoint_shared_keys; 884 else 885 sh_keys = &ep->endpoint_shared_keys; 886 887 key_for_each(key, sh_keys) { 888 if (key->key_id == key_id) { 889 found = 1; 890 break; 891 } 892 } 893 894 if (!found) 895 return -EINVAL; 896 897 if (asoc) { 898 asoc->active_key_id = key_id; 899 sctp_auth_asoc_init_active_key(asoc, GFP_KERNEL); 900 } else 901 ep->active_key_id = key_id; 902 903 return 0; 904} 905 906int sctp_auth_del_key_id(struct sctp_endpoint *ep, 907 struct sctp_association *asoc, 908 __u16 key_id) 909{ 910 struct sctp_shared_key *key; 911 struct list_head *sh_keys; 912 int found = 0; 913 914 /* The key identifier MUST NOT be the current active key 915 * The key identifier MUST correst to an existing key 916 */ 917 if (asoc) { 918 if (asoc->active_key_id == key_id) 919 return -EINVAL; 920 921 sh_keys = &asoc->endpoint_shared_keys; 922 } else { 923 if (ep->active_key_id == key_id) 924 return -EINVAL; 925 926 sh_keys = &ep->endpoint_shared_keys; 927 } 928 929 key_for_each(key, sh_keys) { 930 if (key->key_id == key_id) { 931 found = 1; 932 break; 933 } 934 } 935 936 if (!found) 937 return -EINVAL; 938 939 /* Delete the shared key */ 940 list_del_init(&key->key_list); 941 sctp_auth_shkey_free(key); 942 943 return 0; 944} 945