Vlad Yasevich | 1f48564 | 2007-10-09 01:15:59 -0700 | [diff] [blame] | 1 | /* SCTP kernel reference Implementation |
| 2 | * (C) Copyright 2007 Hewlett-Packard Development Company, L.P. |
| 3 | * |
| 4 | * This file is part of the SCTP kernel reference Implementation |
| 5 | * |
| 6 | * The SCTP reference 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 | * The SCTP reference 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, write to |
| 20 | * the Free Software Foundation, 59 Temple Place - Suite 330, |
| 21 | * Boston, MA 02111-1307, USA. |
| 22 | * |
| 23 | * Please send any bug reports or fixes you make to the |
| 24 | * email address(es): |
| 25 | * lksctp developers <lksctp-developers@lists.sourceforge.net> |
| 26 | * |
| 27 | * Or submit a bug report through the following website: |
| 28 | * http://www.sf.net/projects/lksctp |
| 29 | * |
| 30 | * Written or modified by: |
| 31 | * Vlad Yasevich <vladislav.yasevich@hp.com> |
| 32 | * |
| 33 | * Any bugs reported given to us we will try to fix... any fixes shared will |
| 34 | * be incorporated into the next SCTP release. |
| 35 | */ |
| 36 | |
| 37 | #include <linux/types.h> |
| 38 | #include <linux/crypto.h> |
| 39 | #include <linux/scatterlist.h> |
| 40 | #include <net/sctp/sctp.h> |
| 41 | #include <net/sctp/auth.h> |
| 42 | |
| 43 | static struct sctp_hmac sctp_hmac_list[SCTP_AUTH_NUM_HMACS] = { |
| 44 | { |
| 45 | /* id 0 is reserved. as all 0 */ |
| 46 | .hmac_id = SCTP_AUTH_HMAC_ID_RESERVED_0, |
| 47 | }, |
| 48 | { |
| 49 | .hmac_id = SCTP_AUTH_HMAC_ID_SHA1, |
| 50 | .hmac_name="hmac(sha1)", |
| 51 | .hmac_len = SCTP_SHA1_SIG_SIZE, |
| 52 | }, |
| 53 | { |
| 54 | /* id 2 is reserved as well */ |
| 55 | .hmac_id = SCTP_AUTH_HMAC_ID_RESERVED_2, |
| 56 | }, |
Vlad Yasevich | b7e0fe9 | 2007-11-29 09:53:52 -0500 | [diff] [blame] | 57 | #if defined (CONFIG_CRYPTO_SHA256) || defined (CONFIG_CRYPTO_SHA256_MODULE) |
Vlad Yasevich | 1f48564 | 2007-10-09 01:15:59 -0700 | [diff] [blame] | 58 | { |
| 59 | .hmac_id = SCTP_AUTH_HMAC_ID_SHA256, |
| 60 | .hmac_name="hmac(sha256)", |
| 61 | .hmac_len = SCTP_SHA256_SIG_SIZE, |
| 62 | } |
Vlad Yasevich | b7e0fe9 | 2007-11-29 09:53:52 -0500 | [diff] [blame] | 63 | #endif |
Vlad Yasevich | 1f48564 | 2007-10-09 01:15:59 -0700 | [diff] [blame] | 64 | }; |
| 65 | |
| 66 | |
| 67 | void sctp_auth_key_put(struct sctp_auth_bytes *key) |
| 68 | { |
| 69 | if (!key) |
| 70 | return; |
| 71 | |
| 72 | if (atomic_dec_and_test(&key->refcnt)) { |
| 73 | kfree(key); |
| 74 | SCTP_DBG_OBJCNT_DEC(keys); |
| 75 | } |
| 76 | } |
| 77 | |
| 78 | /* Create a new key structure of a given length */ |
| 79 | static struct sctp_auth_bytes *sctp_auth_create_key(__u32 key_len, gfp_t gfp) |
| 80 | { |
| 81 | struct sctp_auth_bytes *key; |
| 82 | |
| 83 | /* Allocate the shared key */ |
| 84 | key = kmalloc(sizeof(struct sctp_auth_bytes) + key_len, gfp); |
| 85 | if (!key) |
| 86 | return NULL; |
| 87 | |
| 88 | key->len = key_len; |
| 89 | atomic_set(&key->refcnt, 1); |
| 90 | SCTP_DBG_OBJCNT_INC(keys); |
| 91 | |
| 92 | return key; |
| 93 | } |
| 94 | |
| 95 | /* Create a new shared key container with a give key id */ |
| 96 | struct sctp_shared_key *sctp_auth_shkey_create(__u16 key_id, gfp_t gfp) |
| 97 | { |
| 98 | struct sctp_shared_key *new; |
| 99 | |
| 100 | /* Allocate the shared key container */ |
| 101 | new = kzalloc(sizeof(struct sctp_shared_key), gfp); |
| 102 | if (!new) |
| 103 | return NULL; |
| 104 | |
| 105 | INIT_LIST_HEAD(&new->key_list); |
| 106 | new->key_id = key_id; |
| 107 | |
| 108 | return new; |
| 109 | } |
| 110 | |
| 111 | /* Free the shared key stucture */ |
Adrian Bunk | 8ad7c62b | 2007-10-26 04:21:23 -0700 | [diff] [blame] | 112 | static void sctp_auth_shkey_free(struct sctp_shared_key *sh_key) |
Vlad Yasevich | 1f48564 | 2007-10-09 01:15:59 -0700 | [diff] [blame] | 113 | { |
| 114 | BUG_ON(!list_empty(&sh_key->key_list)); |
| 115 | sctp_auth_key_put(sh_key->key); |
| 116 | sh_key->key = NULL; |
| 117 | kfree(sh_key); |
| 118 | } |
| 119 | |
| 120 | /* Destory the entire key list. This is done during the |
| 121 | * associon and endpoint free process. |
| 122 | */ |
| 123 | void sctp_auth_destroy_keys(struct list_head *keys) |
| 124 | { |
| 125 | struct sctp_shared_key *ep_key; |
| 126 | struct sctp_shared_key *tmp; |
| 127 | |
| 128 | if (list_empty(keys)) |
| 129 | return; |
| 130 | |
| 131 | key_for_each_safe(ep_key, tmp, keys) { |
| 132 | list_del_init(&ep_key->key_list); |
| 133 | sctp_auth_shkey_free(ep_key); |
| 134 | } |
| 135 | } |
| 136 | |
| 137 | /* Compare two byte vectors as numbers. Return values |
| 138 | * are: |
| 139 | * 0 - vectors are equal |
| 140 | * < 0 - vector 1 is smaller then vector2 |
| 141 | * > 0 - vector 1 is greater then vector2 |
| 142 | * |
| 143 | * Algorithm is: |
| 144 | * This is performed by selecting the numerically smaller key vector... |
| 145 | * If the key vectors are equal as numbers but differ in length ... |
| 146 | * the shorter vector is considered smaller |
| 147 | * |
| 148 | * Examples (with small values): |
| 149 | * 000123456789 > 123456789 (first number is longer) |
| 150 | * 000123456789 < 234567891 (second number is larger numerically) |
| 151 | * 123456789 > 2345678 (first number is both larger & longer) |
| 152 | */ |
| 153 | static int sctp_auth_compare_vectors(struct sctp_auth_bytes *vector1, |
| 154 | struct sctp_auth_bytes *vector2) |
| 155 | { |
| 156 | int diff; |
| 157 | int i; |
| 158 | const __u8 *longer; |
| 159 | |
| 160 | diff = vector1->len - vector2->len; |
| 161 | if (diff) { |
| 162 | longer = (diff > 0) ? vector1->data : vector2->data; |
| 163 | |
| 164 | /* Check to see if the longer number is |
| 165 | * lead-zero padded. If it is not, it |
| 166 | * is automatically larger numerically. |
| 167 | */ |
| 168 | for (i = 0; i < abs(diff); i++ ) { |
| 169 | if (longer[i] != 0) |
| 170 | return diff; |
| 171 | } |
| 172 | } |
| 173 | |
| 174 | /* lengths are the same, compare numbers */ |
| 175 | return memcmp(vector1->data, vector2->data, vector1->len); |
| 176 | } |
| 177 | |
| 178 | /* |
| 179 | * Create a key vector as described in SCTP-AUTH, Section 6.1 |
| 180 | * The RANDOM parameter, the CHUNKS parameter and the HMAC-ALGO |
| 181 | * parameter sent by each endpoint are concatenated as byte vectors. |
| 182 | * These parameters include the parameter type, parameter length, and |
| 183 | * the parameter value, but padding is omitted; all padding MUST be |
| 184 | * removed from this concatenation before proceeding with further |
| 185 | * computation of keys. Parameters which were not sent are simply |
| 186 | * omitted from the concatenation process. The resulting two vectors |
| 187 | * are called the two key vectors. |
| 188 | */ |
| 189 | static struct sctp_auth_bytes *sctp_auth_make_key_vector( |
| 190 | sctp_random_param_t *random, |
| 191 | sctp_chunks_param_t *chunks, |
| 192 | sctp_hmac_algo_param_t *hmacs, |
| 193 | gfp_t gfp) |
| 194 | { |
| 195 | struct sctp_auth_bytes *new; |
| 196 | __u32 len; |
| 197 | __u32 offset = 0; |
| 198 | |
| 199 | len = ntohs(random->param_hdr.length) + ntohs(hmacs->param_hdr.length); |
| 200 | if (chunks) |
| 201 | len += ntohs(chunks->param_hdr.length); |
| 202 | |
| 203 | new = kmalloc(sizeof(struct sctp_auth_bytes) + len, gfp); |
| 204 | if (!new) |
| 205 | return NULL; |
| 206 | |
| 207 | new->len = len; |
| 208 | |
| 209 | memcpy(new->data, random, ntohs(random->param_hdr.length)); |
| 210 | offset += ntohs(random->param_hdr.length); |
| 211 | |
| 212 | if (chunks) { |
| 213 | memcpy(new->data + offset, chunks, |
| 214 | ntohs(chunks->param_hdr.length)); |
| 215 | offset += ntohs(chunks->param_hdr.length); |
| 216 | } |
| 217 | |
| 218 | memcpy(new->data + offset, hmacs, ntohs(hmacs->param_hdr.length)); |
| 219 | |
| 220 | return new; |
| 221 | } |
| 222 | |
| 223 | |
| 224 | /* Make a key vector based on our local parameters */ |
Adrian Bunk | 8ad7c62b | 2007-10-26 04:21:23 -0700 | [diff] [blame] | 225 | static struct sctp_auth_bytes *sctp_auth_make_local_vector( |
Vlad Yasevich | 1f48564 | 2007-10-09 01:15:59 -0700 | [diff] [blame] | 226 | const struct sctp_association *asoc, |
| 227 | gfp_t gfp) |
| 228 | { |
| 229 | return sctp_auth_make_key_vector( |
| 230 | (sctp_random_param_t*)asoc->c.auth_random, |
| 231 | (sctp_chunks_param_t*)asoc->c.auth_chunks, |
| 232 | (sctp_hmac_algo_param_t*)asoc->c.auth_hmacs, |
| 233 | gfp); |
| 234 | } |
| 235 | |
| 236 | /* Make a key vector based on peer's parameters */ |
Adrian Bunk | 8ad7c62b | 2007-10-26 04:21:23 -0700 | [diff] [blame] | 237 | static struct sctp_auth_bytes *sctp_auth_make_peer_vector( |
Vlad Yasevich | 1f48564 | 2007-10-09 01:15:59 -0700 | [diff] [blame] | 238 | const struct sctp_association *asoc, |
| 239 | gfp_t gfp) |
| 240 | { |
| 241 | return sctp_auth_make_key_vector(asoc->peer.peer_random, |
| 242 | asoc->peer.peer_chunks, |
| 243 | asoc->peer.peer_hmacs, |
| 244 | gfp); |
| 245 | } |
| 246 | |
| 247 | |
| 248 | /* Set the value of the association shared key base on the parameters |
| 249 | * given. The algorithm is: |
| 250 | * From the endpoint pair shared keys and the key vectors the |
| 251 | * association shared keys are computed. This is performed by selecting |
| 252 | * the numerically smaller key vector and concatenating it to the |
| 253 | * endpoint pair shared key, and then concatenating the numerically |
| 254 | * larger key vector to that. The result of the concatenation is the |
| 255 | * association shared key. |
| 256 | */ |
| 257 | static struct sctp_auth_bytes *sctp_auth_asoc_set_secret( |
| 258 | struct sctp_shared_key *ep_key, |
| 259 | struct sctp_auth_bytes *first_vector, |
| 260 | struct sctp_auth_bytes *last_vector, |
| 261 | gfp_t gfp) |
| 262 | { |
| 263 | struct sctp_auth_bytes *secret; |
| 264 | __u32 offset = 0; |
| 265 | __u32 auth_len; |
| 266 | |
| 267 | auth_len = first_vector->len + last_vector->len; |
| 268 | if (ep_key->key) |
| 269 | auth_len += ep_key->key->len; |
| 270 | |
| 271 | secret = sctp_auth_create_key(auth_len, gfp); |
| 272 | if (!secret) |
| 273 | return NULL; |
| 274 | |
| 275 | if (ep_key->key) { |
| 276 | memcpy(secret->data, ep_key->key->data, ep_key->key->len); |
| 277 | offset += ep_key->key->len; |
| 278 | } |
| 279 | |
| 280 | memcpy(secret->data + offset, first_vector->data, first_vector->len); |
| 281 | offset += first_vector->len; |
| 282 | |
| 283 | memcpy(secret->data + offset, last_vector->data, last_vector->len); |
| 284 | |
| 285 | return secret; |
| 286 | } |
| 287 | |
| 288 | /* Create an association shared key. Follow the algorithm |
| 289 | * described in SCTP-AUTH, Section 6.1 |
| 290 | */ |
| 291 | static struct sctp_auth_bytes *sctp_auth_asoc_create_secret( |
| 292 | const struct sctp_association *asoc, |
| 293 | struct sctp_shared_key *ep_key, |
| 294 | gfp_t gfp) |
| 295 | { |
| 296 | struct sctp_auth_bytes *local_key_vector; |
| 297 | struct sctp_auth_bytes *peer_key_vector; |
| 298 | struct sctp_auth_bytes *first_vector, |
| 299 | *last_vector; |
| 300 | struct sctp_auth_bytes *secret = NULL; |
| 301 | int cmp; |
| 302 | |
| 303 | |
| 304 | /* Now we need to build the key vectors |
| 305 | * SCTP-AUTH , Section 6.1 |
| 306 | * The RANDOM parameter, the CHUNKS parameter and the HMAC-ALGO |
| 307 | * parameter sent by each endpoint are concatenated as byte vectors. |
| 308 | * These parameters include the parameter type, parameter length, and |
| 309 | * the parameter value, but padding is omitted; all padding MUST be |
| 310 | * removed from this concatenation before proceeding with further |
| 311 | * computation of keys. Parameters which were not sent are simply |
| 312 | * omitted from the concatenation process. The resulting two vectors |
| 313 | * are called the two key vectors. |
| 314 | */ |
| 315 | |
| 316 | local_key_vector = sctp_auth_make_local_vector(asoc, gfp); |
| 317 | peer_key_vector = sctp_auth_make_peer_vector(asoc, gfp); |
| 318 | |
| 319 | if (!peer_key_vector || !local_key_vector) |
| 320 | goto out; |
| 321 | |
| 322 | /* Figure out the order in wich the key_vectors will be |
| 323 | * added to the endpoint shared key. |
| 324 | * SCTP-AUTH, Section 6.1: |
| 325 | * This is performed by selecting the numerically smaller key |
| 326 | * vector and concatenating it to the endpoint pair shared |
| 327 | * key, and then concatenating the numerically larger key |
| 328 | * vector to that. If the key vectors are equal as numbers |
| 329 | * but differ in length, then the concatenation order is the |
| 330 | * endpoint shared key, followed by the shorter key vector, |
| 331 | * followed by the longer key vector. Otherwise, the key |
| 332 | * vectors are identical, and may be concatenated to the |
| 333 | * endpoint pair key in any order. |
| 334 | */ |
| 335 | cmp = sctp_auth_compare_vectors(local_key_vector, |
| 336 | peer_key_vector); |
| 337 | if (cmp < 0) { |
| 338 | first_vector = local_key_vector; |
| 339 | last_vector = peer_key_vector; |
| 340 | } else { |
| 341 | first_vector = peer_key_vector; |
| 342 | last_vector = local_key_vector; |
| 343 | } |
| 344 | |
| 345 | secret = sctp_auth_asoc_set_secret(ep_key, first_vector, last_vector, |
| 346 | gfp); |
| 347 | out: |
| 348 | kfree(local_key_vector); |
| 349 | kfree(peer_key_vector); |
| 350 | |
| 351 | return secret; |
| 352 | } |
| 353 | |
| 354 | /* |
| 355 | * Populate the association overlay list with the list |
| 356 | * from the endpoint. |
| 357 | */ |
| 358 | int sctp_auth_asoc_copy_shkeys(const struct sctp_endpoint *ep, |
| 359 | struct sctp_association *asoc, |
| 360 | gfp_t gfp) |
| 361 | { |
| 362 | struct sctp_shared_key *sh_key; |
| 363 | struct sctp_shared_key *new; |
| 364 | |
| 365 | BUG_ON(!list_empty(&asoc->endpoint_shared_keys)); |
| 366 | |
| 367 | key_for_each(sh_key, &ep->endpoint_shared_keys) { |
| 368 | new = sctp_auth_shkey_create(sh_key->key_id, gfp); |
| 369 | if (!new) |
| 370 | goto nomem; |
| 371 | |
| 372 | new->key = sh_key->key; |
| 373 | sctp_auth_key_hold(new->key); |
| 374 | list_add(&new->key_list, &asoc->endpoint_shared_keys); |
| 375 | } |
| 376 | |
| 377 | return 0; |
| 378 | |
| 379 | nomem: |
| 380 | sctp_auth_destroy_keys(&asoc->endpoint_shared_keys); |
| 381 | return -ENOMEM; |
| 382 | } |
| 383 | |
| 384 | |
| 385 | /* Public interface to creat the association shared key. |
| 386 | * See code above for the algorithm. |
| 387 | */ |
| 388 | int sctp_auth_asoc_init_active_key(struct sctp_association *asoc, gfp_t gfp) |
| 389 | { |
| 390 | struct sctp_auth_bytes *secret; |
| 391 | struct sctp_shared_key *ep_key; |
| 392 | |
| 393 | /* If we don't support AUTH, or peer is not capable |
| 394 | * we don't need to do anything. |
| 395 | */ |
| 396 | if (!sctp_auth_enable || !asoc->peer.auth_capable) |
| 397 | return 0; |
| 398 | |
| 399 | /* If the key_id is non-zero and we couldn't find an |
| 400 | * endpoint pair shared key, we can't compute the |
| 401 | * secret. |
| 402 | * For key_id 0, endpoint pair shared key is a NULL key. |
| 403 | */ |
| 404 | ep_key = sctp_auth_get_shkey(asoc, asoc->active_key_id); |
| 405 | BUG_ON(!ep_key); |
| 406 | |
| 407 | secret = sctp_auth_asoc_create_secret(asoc, ep_key, gfp); |
| 408 | if (!secret) |
| 409 | return -ENOMEM; |
| 410 | |
| 411 | sctp_auth_key_put(asoc->asoc_shared_key); |
| 412 | asoc->asoc_shared_key = secret; |
| 413 | |
| 414 | return 0; |
| 415 | } |
| 416 | |
| 417 | |
| 418 | /* Find the endpoint pair shared key based on the key_id */ |
| 419 | struct sctp_shared_key *sctp_auth_get_shkey( |
| 420 | const struct sctp_association *asoc, |
| 421 | __u16 key_id) |
| 422 | { |
Wei Yongjun | 7cc08b5 | 2008-02-05 03:03:06 -0800 | [diff] [blame] | 423 | struct sctp_shared_key *key; |
Vlad Yasevich | 1f48564 | 2007-10-09 01:15:59 -0700 | [diff] [blame] | 424 | |
| 425 | /* First search associations set of endpoint pair shared keys */ |
| 426 | key_for_each(key, &asoc->endpoint_shared_keys) { |
| 427 | if (key->key_id == key_id) |
Wei Yongjun | 7cc08b5 | 2008-02-05 03:03:06 -0800 | [diff] [blame] | 428 | return key; |
Vlad Yasevich | 1f48564 | 2007-10-09 01:15:59 -0700 | [diff] [blame] | 429 | } |
| 430 | |
Wei Yongjun | 7cc08b5 | 2008-02-05 03:03:06 -0800 | [diff] [blame] | 431 | return NULL; |
Vlad Yasevich | 1f48564 | 2007-10-09 01:15:59 -0700 | [diff] [blame] | 432 | } |
| 433 | |
| 434 | /* |
| 435 | * Initialize all the possible digest transforms that we can use. Right now |
| 436 | * now, the supported digests are SHA1 and SHA256. We do this here once |
| 437 | * because of the restrictiong that transforms may only be allocated in |
| 438 | * user context. This forces us to pre-allocated all possible transforms |
| 439 | * at the endpoint init time. |
| 440 | */ |
| 441 | int sctp_auth_init_hmacs(struct sctp_endpoint *ep, gfp_t gfp) |
| 442 | { |
| 443 | struct crypto_hash *tfm = NULL; |
| 444 | __u16 id; |
| 445 | |
| 446 | /* if the transforms are already allocted, we are done */ |
| 447 | if (!sctp_auth_enable) { |
| 448 | ep->auth_hmacs = NULL; |
| 449 | return 0; |
| 450 | } |
| 451 | |
| 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 | |
| 487 | out_err: |
| 488 | /* Clean up any successfull allocations */ |
| 489 | sctp_auth_destroy_hmacs(ep->auth_hmacs); |
| 490 | return -ENOMEM; |
| 491 | } |
| 492 | |
| 493 | /* Destroy the hmac tfm array */ |
| 494 | void 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 | { |
| 503 | if (auth_hmacs[i]) |
| 504 | crypto_free_hash(auth_hmacs[i]); |
| 505 | } |
| 506 | kfree(auth_hmacs); |
| 507 | } |
| 508 | |
| 509 | |
| 510 | struct sctp_hmac *sctp_auth_get_hmac(__u16 hmac_id) |
| 511 | { |
| 512 | return &sctp_hmac_list[hmac_id]; |
| 513 | } |
| 514 | |
| 515 | /* Get an hmac description information that we can use to build |
| 516 | * the AUTH chunk |
| 517 | */ |
| 518 | struct sctp_hmac *sctp_auth_asoc_get_hmac(const struct sctp_association *asoc) |
| 519 | { |
| 520 | struct sctp_hmac_algo_param *hmacs; |
| 521 | __u16 n_elt; |
| 522 | __u16 id = 0; |
| 523 | int i; |
| 524 | |
| 525 | /* If we have a default entry, use it */ |
| 526 | if (asoc->default_hmac_id) |
| 527 | return &sctp_hmac_list[asoc->default_hmac_id]; |
| 528 | |
| 529 | /* Since we do not have a default entry, find the first entry |
| 530 | * we support and return that. Do not cache that id. |
| 531 | */ |
| 532 | hmacs = asoc->peer.peer_hmacs; |
| 533 | if (!hmacs) |
| 534 | return NULL; |
| 535 | |
| 536 | n_elt = (ntohs(hmacs->param_hdr.length) - sizeof(sctp_paramhdr_t)) >> 1; |
| 537 | for (i = 0; i < n_elt; i++) { |
| 538 | id = ntohs(hmacs->hmac_ids[i]); |
| 539 | |
| 540 | /* Check the id is in the supported range */ |
| 541 | if (id > SCTP_AUTH_HMAC_ID_MAX) |
| 542 | continue; |
| 543 | |
| 544 | /* See is we support the id. Supported IDs have name and |
| 545 | * length fields set, so that we can allocated and use |
| 546 | * them. We can safely just check for name, for without the |
| 547 | * name, we can't allocate the TFM. |
| 548 | */ |
| 549 | if (!sctp_hmac_list[id].hmac_name) |
| 550 | continue; |
| 551 | |
| 552 | break; |
| 553 | } |
| 554 | |
| 555 | if (id == 0) |
| 556 | return NULL; |
| 557 | |
| 558 | return &sctp_hmac_list[id]; |
| 559 | } |
| 560 | |
Al Viro | d06f608 | 2007-10-29 05:03:23 +0000 | [diff] [blame] | 561 | static int __sctp_auth_find_hmacid(__be16 *hmacs, int n_elts, __be16 hmac_id) |
Vlad Yasevich | 1f48564 | 2007-10-09 01:15:59 -0700 | [diff] [blame] | 562 | { |
| 563 | int found = 0; |
| 564 | int i; |
| 565 | |
| 566 | for (i = 0; i < n_elts; i++) { |
| 567 | if (hmac_id == hmacs[i]) { |
| 568 | found = 1; |
| 569 | break; |
| 570 | } |
| 571 | } |
| 572 | |
| 573 | return found; |
| 574 | } |
| 575 | |
| 576 | /* See if the HMAC_ID is one that we claim as supported */ |
| 577 | int sctp_auth_asoc_verify_hmac_id(const struct sctp_association *asoc, |
Al Viro | d06f608 | 2007-10-29 05:03:23 +0000 | [diff] [blame] | 578 | __be16 hmac_id) |
Vlad Yasevich | 1f48564 | 2007-10-09 01:15:59 -0700 | [diff] [blame] | 579 | { |
| 580 | struct sctp_hmac_algo_param *hmacs; |
| 581 | __u16 n_elt; |
| 582 | |
| 583 | if (!asoc) |
| 584 | return 0; |
| 585 | |
| 586 | hmacs = (struct sctp_hmac_algo_param *)asoc->c.auth_hmacs; |
| 587 | n_elt = (ntohs(hmacs->param_hdr.length) - sizeof(sctp_paramhdr_t)) >> 1; |
| 588 | |
| 589 | return __sctp_auth_find_hmacid(hmacs->hmac_ids, n_elt, hmac_id); |
| 590 | } |
| 591 | |
| 592 | |
| 593 | /* Cache the default HMAC id. This to follow this text from SCTP-AUTH: |
| 594 | * Section 6.1: |
| 595 | * The receiver of a HMAC-ALGO parameter SHOULD use the first listed |
| 596 | * algorithm it supports. |
| 597 | */ |
| 598 | void sctp_auth_asoc_set_default_hmac(struct sctp_association *asoc, |
| 599 | struct sctp_hmac_algo_param *hmacs) |
| 600 | { |
| 601 | struct sctp_endpoint *ep; |
| 602 | __u16 id; |
| 603 | int i; |
| 604 | int n_params; |
| 605 | |
| 606 | /* if the default id is already set, use it */ |
| 607 | if (asoc->default_hmac_id) |
| 608 | return; |
| 609 | |
| 610 | n_params = (ntohs(hmacs->param_hdr.length) |
| 611 | - sizeof(sctp_paramhdr_t)) >> 1; |
| 612 | ep = asoc->ep; |
| 613 | for (i = 0; i < n_params; i++) { |
| 614 | id = ntohs(hmacs->hmac_ids[i]); |
| 615 | |
| 616 | /* Check the id is in the supported range */ |
| 617 | if (id > SCTP_AUTH_HMAC_ID_MAX) |
| 618 | continue; |
| 619 | |
| 620 | /* If this TFM has been allocated, use this id */ |
| 621 | if (ep->auth_hmacs[id]) { |
| 622 | asoc->default_hmac_id = id; |
| 623 | break; |
| 624 | } |
| 625 | } |
| 626 | } |
| 627 | |
| 628 | |
| 629 | /* Check to see if the given chunk is supposed to be authenticated */ |
| 630 | static int __sctp_auth_cid(sctp_cid_t chunk, struct sctp_chunks_param *param) |
| 631 | { |
| 632 | unsigned short len; |
| 633 | int found = 0; |
| 634 | int i; |
| 635 | |
Vlad Yasevich | 555d3d5 | 2007-11-29 08:56:16 -0500 | [diff] [blame] | 636 | if (!param || param->param_hdr.length == 0) |
Vlad Yasevich | 1f48564 | 2007-10-09 01:15:59 -0700 | [diff] [blame] | 637 | return 0; |
| 638 | |
| 639 | len = ntohs(param->param_hdr.length) - sizeof(sctp_paramhdr_t); |
| 640 | |
| 641 | /* SCTP-AUTH, Section 3.2 |
| 642 | * The chunk types for INIT, INIT-ACK, SHUTDOWN-COMPLETE and AUTH |
| 643 | * chunks MUST NOT be listed in the CHUNKS parameter. However, if |
| 644 | * a CHUNKS parameter is received then the types for INIT, INIT-ACK, |
| 645 | * SHUTDOWN-COMPLETE and AUTH chunks MUST be ignored. |
| 646 | */ |
| 647 | for (i = 0; !found && i < len; i++) { |
| 648 | switch (param->chunks[i]) { |
| 649 | case SCTP_CID_INIT: |
| 650 | case SCTP_CID_INIT_ACK: |
| 651 | case SCTP_CID_SHUTDOWN_COMPLETE: |
| 652 | case SCTP_CID_AUTH: |
| 653 | break; |
| 654 | |
| 655 | default: |
| 656 | if (param->chunks[i] == chunk) |
| 657 | found = 1; |
| 658 | break; |
| 659 | } |
| 660 | } |
| 661 | |
| 662 | return found; |
| 663 | } |
| 664 | |
| 665 | /* Check if peer requested that this chunk is authenticated */ |
| 666 | int sctp_auth_send_cid(sctp_cid_t chunk, const struct sctp_association *asoc) |
| 667 | { |
| 668 | if (!sctp_auth_enable || !asoc || !asoc->peer.auth_capable) |
| 669 | return 0; |
| 670 | |
| 671 | return __sctp_auth_cid(chunk, asoc->peer.peer_chunks); |
| 672 | } |
| 673 | |
| 674 | /* Check if we requested that peer authenticate this chunk. */ |
| 675 | int sctp_auth_recv_cid(sctp_cid_t chunk, const struct sctp_association *asoc) |
| 676 | { |
| 677 | if (!sctp_auth_enable || !asoc) |
| 678 | return 0; |
| 679 | |
| 680 | return __sctp_auth_cid(chunk, |
| 681 | (struct sctp_chunks_param *)asoc->c.auth_chunks); |
| 682 | } |
| 683 | |
| 684 | /* SCTP-AUTH: Section 6.2: |
| 685 | * The sender MUST calculate the MAC as described in RFC2104 [2] using |
| 686 | * the hash function H as described by the MAC Identifier and the shared |
| 687 | * association key K based on the endpoint pair shared key described by |
| 688 | * the shared key identifier. The 'data' used for the computation of |
| 689 | * the AUTH-chunk is given by the AUTH chunk with its HMAC field set to |
| 690 | * zero (as shown in Figure 6) followed by all chunks that are placed |
| 691 | * after the AUTH chunk in the SCTP packet. |
| 692 | */ |
| 693 | void sctp_auth_calculate_hmac(const struct sctp_association *asoc, |
| 694 | struct sk_buff *skb, |
| 695 | struct sctp_auth_chunk *auth, |
| 696 | gfp_t gfp) |
| 697 | { |
| 698 | struct scatterlist sg; |
| 699 | struct hash_desc desc; |
| 700 | struct sctp_auth_bytes *asoc_key; |
| 701 | __u16 key_id, hmac_id; |
| 702 | __u8 *digest; |
| 703 | unsigned char *end; |
| 704 | int free_key = 0; |
| 705 | |
| 706 | /* Extract the info we need: |
| 707 | * - hmac id |
| 708 | * - key id |
| 709 | */ |
| 710 | key_id = ntohs(auth->auth_hdr.shkey_id); |
| 711 | hmac_id = ntohs(auth->auth_hdr.hmac_id); |
| 712 | |
| 713 | if (key_id == asoc->active_key_id) |
| 714 | asoc_key = asoc->asoc_shared_key; |
| 715 | else { |
| 716 | struct sctp_shared_key *ep_key; |
| 717 | |
| 718 | ep_key = sctp_auth_get_shkey(asoc, key_id); |
| 719 | if (!ep_key) |
| 720 | return; |
| 721 | |
| 722 | asoc_key = sctp_auth_asoc_create_secret(asoc, ep_key, gfp); |
| 723 | if (!asoc_key) |
| 724 | return; |
| 725 | |
| 726 | free_key = 1; |
| 727 | } |
| 728 | |
| 729 | /* set up scatter list */ |
| 730 | end = skb_tail_pointer(skb); |
Herbert Xu | 68e3f5d | 2007-10-27 00:52:07 -0700 | [diff] [blame] | 731 | sg_init_one(&sg, auth, end - (unsigned char *)auth); |
Vlad Yasevich | 1f48564 | 2007-10-09 01:15:59 -0700 | [diff] [blame] | 732 | |
| 733 | desc.tfm = asoc->ep->auth_hmacs[hmac_id]; |
| 734 | desc.flags = 0; |
| 735 | |
| 736 | digest = auth->auth_hdr.hmac; |
| 737 | if (crypto_hash_setkey(desc.tfm, &asoc_key->data[0], asoc_key->len)) |
| 738 | goto free; |
| 739 | |
| 740 | crypto_hash_digest(&desc, &sg, sg.length, digest); |
| 741 | |
| 742 | free: |
| 743 | if (free_key) |
| 744 | sctp_auth_key_put(asoc_key); |
| 745 | } |
Vlad Yasevich | 65b07e5 | 2007-09-16 19:34:00 -0700 | [diff] [blame] | 746 | |
| 747 | /* API Helpers */ |
| 748 | |
| 749 | /* Add a chunk to the endpoint authenticated chunk list */ |
| 750 | int sctp_auth_ep_add_chunkid(struct sctp_endpoint *ep, __u8 chunk_id) |
| 751 | { |
| 752 | struct sctp_chunks_param *p = ep->auth_chunk_list; |
| 753 | __u16 nchunks; |
| 754 | __u16 param_len; |
| 755 | |
| 756 | /* If this chunk is already specified, we are done */ |
| 757 | if (__sctp_auth_cid(chunk_id, p)) |
| 758 | return 0; |
| 759 | |
| 760 | /* Check if we can add this chunk to the array */ |
| 761 | param_len = ntohs(p->param_hdr.length); |
| 762 | nchunks = param_len - sizeof(sctp_paramhdr_t); |
| 763 | if (nchunks == SCTP_NUM_CHUNK_TYPES) |
| 764 | return -EINVAL; |
| 765 | |
| 766 | p->chunks[nchunks] = chunk_id; |
| 767 | p->param_hdr.length = htons(param_len + 1); |
| 768 | return 0; |
| 769 | } |
| 770 | |
| 771 | /* Add hmac identifires to the endpoint list of supported hmac ids */ |
| 772 | int sctp_auth_ep_set_hmacs(struct sctp_endpoint *ep, |
| 773 | struct sctp_hmacalgo *hmacs) |
| 774 | { |
| 775 | int has_sha1 = 0; |
| 776 | __u16 id; |
| 777 | int i; |
| 778 | |
| 779 | /* Scan the list looking for unsupported id. Also make sure that |
| 780 | * SHA1 is specified. |
| 781 | */ |
| 782 | for (i = 0; i < hmacs->shmac_num_idents; i++) { |
| 783 | id = hmacs->shmac_idents[i]; |
| 784 | |
| 785 | if (SCTP_AUTH_HMAC_ID_SHA1 == id) |
| 786 | has_sha1 = 1; |
| 787 | |
| 788 | if (!sctp_hmac_list[id].hmac_name) |
| 789 | return -EOPNOTSUPP; |
| 790 | } |
| 791 | |
| 792 | if (!has_sha1) |
| 793 | return -EINVAL; |
| 794 | |
| 795 | memcpy(ep->auth_hmacs_list->hmac_ids, &hmacs->shmac_idents[0], |
| 796 | hmacs->shmac_num_idents * sizeof(__u16)); |
| 797 | ep->auth_hmacs_list->param_hdr.length = htons(sizeof(sctp_paramhdr_t) + |
| 798 | hmacs->shmac_num_idents * sizeof(__u16)); |
| 799 | return 0; |
| 800 | } |
| 801 | |
| 802 | /* Set a new shared key on either endpoint or association. If the |
| 803 | * the key with a same ID already exists, replace the key (remove the |
| 804 | * old key and add a new one). |
| 805 | */ |
| 806 | int sctp_auth_set_key(struct sctp_endpoint *ep, |
| 807 | struct sctp_association *asoc, |
| 808 | struct sctp_authkey *auth_key) |
| 809 | { |
| 810 | struct sctp_shared_key *cur_key = NULL; |
| 811 | struct sctp_auth_bytes *key; |
| 812 | struct list_head *sh_keys; |
| 813 | int replace = 0; |
| 814 | |
| 815 | /* Try to find the given key id to see if |
| 816 | * we are doing a replace, or adding a new key |
| 817 | */ |
| 818 | if (asoc) |
| 819 | sh_keys = &asoc->endpoint_shared_keys; |
| 820 | else |
| 821 | sh_keys = &ep->endpoint_shared_keys; |
| 822 | |
| 823 | key_for_each(cur_key, sh_keys) { |
| 824 | if (cur_key->key_id == auth_key->sca_keynumber) { |
| 825 | replace = 1; |
| 826 | break; |
| 827 | } |
| 828 | } |
| 829 | |
| 830 | /* If we are not replacing a key id, we need to allocate |
| 831 | * a shared key. |
| 832 | */ |
| 833 | if (!replace) { |
| 834 | cur_key = sctp_auth_shkey_create(auth_key->sca_keynumber, |
| 835 | GFP_KERNEL); |
| 836 | if (!cur_key) |
| 837 | return -ENOMEM; |
| 838 | } |
| 839 | |
| 840 | /* Create a new key data based on the info passed in */ |
| 841 | key = sctp_auth_create_key(auth_key->sca_keylen, GFP_KERNEL); |
| 842 | if (!key) |
| 843 | goto nomem; |
| 844 | |
| 845 | memcpy(key->data, &auth_key->sca_key[0], auth_key->sca_keylen); |
| 846 | |
| 847 | /* If we are replacing, remove the old keys data from the |
| 848 | * key id. If we are adding new key id, add it to the |
| 849 | * list. |
| 850 | */ |
| 851 | if (replace) |
| 852 | sctp_auth_key_put(cur_key->key); |
| 853 | else |
| 854 | list_add(&cur_key->key_list, sh_keys); |
| 855 | |
| 856 | cur_key->key = key; |
| 857 | sctp_auth_key_hold(key); |
| 858 | |
| 859 | return 0; |
| 860 | nomem: |
| 861 | if (!replace) |
| 862 | sctp_auth_shkey_free(cur_key); |
| 863 | |
| 864 | return -ENOMEM; |
| 865 | } |
| 866 | |
| 867 | int sctp_auth_set_active_key(struct sctp_endpoint *ep, |
| 868 | struct sctp_association *asoc, |
| 869 | __u16 key_id) |
| 870 | { |
| 871 | struct sctp_shared_key *key; |
| 872 | struct list_head *sh_keys; |
| 873 | int found = 0; |
| 874 | |
| 875 | /* The key identifier MUST correst to an existing key */ |
| 876 | if (asoc) |
| 877 | sh_keys = &asoc->endpoint_shared_keys; |
| 878 | else |
| 879 | sh_keys = &ep->endpoint_shared_keys; |
| 880 | |
| 881 | key_for_each(key, sh_keys) { |
| 882 | if (key->key_id == key_id) { |
| 883 | found = 1; |
| 884 | break; |
| 885 | } |
| 886 | } |
| 887 | |
| 888 | if (!found) |
| 889 | return -EINVAL; |
| 890 | |
| 891 | if (asoc) { |
| 892 | asoc->active_key_id = key_id; |
| 893 | sctp_auth_asoc_init_active_key(asoc, GFP_KERNEL); |
| 894 | } else |
| 895 | ep->active_key_id = key_id; |
| 896 | |
| 897 | return 0; |
| 898 | } |
| 899 | |
| 900 | int sctp_auth_del_key_id(struct sctp_endpoint *ep, |
| 901 | struct sctp_association *asoc, |
| 902 | __u16 key_id) |
| 903 | { |
| 904 | struct sctp_shared_key *key; |
| 905 | struct list_head *sh_keys; |
| 906 | int found = 0; |
| 907 | |
| 908 | /* The key identifier MUST NOT be the current active key |
| 909 | * The key identifier MUST correst to an existing key |
| 910 | */ |
| 911 | if (asoc) { |
| 912 | if (asoc->active_key_id == key_id) |
| 913 | return -EINVAL; |
| 914 | |
| 915 | sh_keys = &asoc->endpoint_shared_keys; |
| 916 | } else { |
| 917 | if (ep->active_key_id == key_id) |
| 918 | return -EINVAL; |
| 919 | |
| 920 | sh_keys = &ep->endpoint_shared_keys; |
| 921 | } |
| 922 | |
| 923 | key_for_each(key, sh_keys) { |
| 924 | if (key->key_id == key_id) { |
| 925 | found = 1; |
| 926 | break; |
| 927 | } |
| 928 | } |
| 929 | |
| 930 | if (!found) |
| 931 | return -EINVAL; |
| 932 | |
| 933 | /* Delete the shared key */ |
| 934 | list_del_init(&key->key_list); |
| 935 | sctp_auth_shkey_free(key); |
| 936 | |
| 937 | return 0; |
| 938 | } |