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60c778b2 | 1 | /* SCTP kernel implementation |
1f485649 VY |
2 | * (C) Copyright 2007 Hewlett-Packard Development Company, L.P. |
3 | * | |
60c778b2 | 4 | * This file is part of the SCTP kernel implementation |
1f485649 | 5 | * |
60c778b2 | 6 | * This SCTP implementation is free software; |
1f485649 VY |
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 | * | |
60c778b2 | 12 | * This SCTP implementation is distributed in the hope that it |
1f485649 VY |
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 | |
4b2f13a2 JK |
19 | * along with GNU CC; see the file COPYING. If not, see |
20 | * <http://www.gnu.org/licenses/>. | |
1f485649 VY |
21 | * |
22 | * Please send any bug reports or fixes you make to the | |
23 | * email address(es): | |
91705c61 | 24 | * lksctp developers <linux-sctp@vger.kernel.org> |
1f485649 | 25 | * |
1f485649 VY |
26 | * Written or modified by: |
27 | * Vlad Yasevich <vladislav.yasevich@hp.com> | |
1f485649 VY |
28 | */ |
29 | ||
5a0e3ad6 | 30 | #include <linux/slab.h> |
1f485649 VY |
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 | ||
37 | static 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, | |
cb3f837b | 44 | .hmac_name = "hmac(sha1)", |
1f485649 VY |
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 | }, | |
b7e0fe9f | 51 | #if defined (CONFIG_CRYPTO_SHA256) || defined (CONFIG_CRYPTO_SHA256_MODULE) |
1f485649 VY |
52 | { |
53 | .hmac_id = SCTP_AUTH_HMAC_ID_SHA256, | |
cb3f837b | 54 | .hmac_name = "hmac(sha256)", |
1f485649 VY |
55 | .hmac_len = SCTP_SHA256_SIG_SIZE, |
56 | } | |
b7e0fe9f | 57 | #endif |
1f485649 VY |
58 | }; |
59 | ||
60 | ||
61 | void sctp_auth_key_put(struct sctp_auth_bytes *key) | |
62 | { | |
63 | if (!key) | |
64 | return; | |
65 | ||
66 | if (atomic_dec_and_test(&key->refcnt)) { | |
586c31f3 | 67 | kzfree(key); |
1f485649 VY |
68 | SCTP_DBG_OBJCNT_DEC(keys); |
69 | } | |
70 | } | |
71 | ||
72 | /* Create a new key structure of a given length */ | |
73 | static struct sctp_auth_bytes *sctp_auth_create_key(__u32 key_len, gfp_t gfp) | |
74 | { | |
75 | struct sctp_auth_bytes *key; | |
76 | ||
30c2235c | 77 | /* Verify that we are not going to overflow INT_MAX */ |
c89304b8 | 78 | if (key_len > (INT_MAX - sizeof(struct sctp_auth_bytes))) |
30c2235c VY |
79 | return NULL; |
80 | ||
1f485649 VY |
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 */ | |
94 | struct 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 | ||
25985edc | 109 | /* Free the shared key structure */ |
8ad7c62b | 110 | static void sctp_auth_shkey_free(struct sctp_shared_key *sh_key) |
1f485649 VY |
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 | ||
25985edc | 118 | /* Destroy the entire key list. This is done during the |
1f485649 VY |
119 | * associon and endpoint free process. |
120 | */ | |
121 | void 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 | |
025dfdaf FS |
138 | * < 0 - vector 1 is smaller than vector2 |
139 | * > 0 - vector 1 is greater than vector2 | |
1f485649 VY |
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 | */ | |
151 | static 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 | */ | |
cb3f837b | 166 | for (i = 0; i < abs(diff); i++) { |
1f485649 VY |
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 | */ | |
187 | static 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; | |
241448c2 | 196 | __u16 random_len, hmacs_len, chunks_len = 0; |
1f485649 | 197 | |
241448c2 DB |
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; | |
1f485649 | 204 | |
03536e23 | 205 | new = sctp_auth_create_key(len, gfp); |
1f485649 VY |
206 | if (!new) |
207 | return NULL; | |
208 | ||
241448c2 DB |
209 | memcpy(new->data, random, random_len); |
210 | offset += random_len; | |
1f485649 VY |
211 | |
212 | if (chunks) { | |
241448c2 DB |
213 | memcpy(new->data + offset, chunks, chunks_len); |
214 | offset += chunks_len; | |
1f485649 VY |
215 | } |
216 | ||
241448c2 | 217 | memcpy(new->data + offset, hmacs, hmacs_len); |
1f485649 VY |
218 | |
219 | return new; | |
220 | } | |
221 | ||
222 | ||
223 | /* Make a key vector based on our local parameters */ | |
8ad7c62b | 224 | static struct sctp_auth_bytes *sctp_auth_make_local_vector( |
1f485649 VY |
225 | const struct sctp_association *asoc, |
226 | gfp_t gfp) | |
227 | { | |
228 | return sctp_auth_make_key_vector( | |
26ac8e5f | 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, | |
1f485649 VY |
232 | gfp); |
233 | } | |
234 | ||
235 | /* Make a key vector based on peer's parameters */ | |
8ad7c62b | 236 | static struct sctp_auth_bytes *sctp_auth_make_peer_vector( |
1f485649 VY |
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 | */ | |
256 | static 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 | */ | |
290 | static 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 | ||
25985edc | 321 | /* Figure out the order in which the key_vectors will be |
1f485649 VY |
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); | |
346 | out: | |
03536e23 DB |
347 | sctp_auth_key_put(local_key_vector); |
348 | sctp_auth_key_put(peer_key_vector); | |
1f485649 VY |
349 | |
350 | return secret; | |
351 | } | |
352 | ||
353 | /* | |
354 | * Populate the association overlay list with the list | |
355 | * from the endpoint. | |
356 | */ | |
357 | int 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 | ||
378 | nomem: | |
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 | */ | |
387 | int sctp_auth_asoc_init_active_key(struct sctp_association *asoc, gfp_t gfp) | |
388 | { | |
e1fc3b14 | 389 | struct net *net = sock_net(asoc->base.sk); |
1f485649 VY |
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 | */ | |
e1fc3b14 | 396 | if (!net->sctp.auth_enable || !asoc->peer.auth_capable) |
1f485649 VY |
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 | { | |
7cc08b55 | 423 | struct sctp_shared_key *key; |
1f485649 VY |
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) | |
7cc08b55 | 428 | return key; |
1f485649 VY |
429 | } |
430 | ||
7cc08b55 | 431 | return NULL; |
1f485649 VY |
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 | { | |
e1fc3b14 | 443 | struct net *net = sock_net(ep->base.sk); |
1f485649 VY |
444 | struct crypto_hash *tfm = NULL; |
445 | __u16 id; | |
446 | ||
447 | /* if the transforms are already allocted, we are done */ | |
e1fc3b14 | 448 | if (!net->sctp.auth_enable) { |
1f485649 VY |
449 | ep->auth_hmacs = NULL; |
450 | return 0; | |
451 | } | |
452 | ||
453 | if (ep->auth_hmacs) | |
454 | return 0; | |
455 | ||
456 | /* Allocated the array of pointers to transorms */ | |
457 | ep->auth_hmacs = kzalloc( | |
458 | sizeof(struct crypto_hash *) * SCTP_AUTH_NUM_HMACS, | |
459 | gfp); | |
460 | if (!ep->auth_hmacs) | |
461 | return -ENOMEM; | |
462 | ||
463 | for (id = 0; id < SCTP_AUTH_NUM_HMACS; id++) { | |
464 | ||
465 | /* See is we support the id. Supported IDs have name and | |
466 | * length fields set, so that we can allocated and use | |
467 | * them. We can safely just check for name, for without the | |
468 | * name, we can't allocate the TFM. | |
469 | */ | |
470 | if (!sctp_hmac_list[id].hmac_name) | |
471 | continue; | |
472 | ||
473 | /* If this TFM has been allocated, we are all set */ | |
474 | if (ep->auth_hmacs[id]) | |
475 | continue; | |
476 | ||
477 | /* Allocate the ID */ | |
478 | tfm = crypto_alloc_hash(sctp_hmac_list[id].hmac_name, 0, | |
479 | CRYPTO_ALG_ASYNC); | |
480 | if (IS_ERR(tfm)) | |
481 | goto out_err; | |
482 | ||
483 | ep->auth_hmacs[id] = tfm; | |
484 | } | |
485 | ||
486 | return 0; | |
487 | ||
488 | out_err: | |
73ac36ea | 489 | /* Clean up any successful allocations */ |
1f485649 VY |
490 | sctp_auth_destroy_hmacs(ep->auth_hmacs); |
491 | return -ENOMEM; | |
492 | } | |
493 | ||
494 | /* Destroy the hmac tfm array */ | |
495 | void sctp_auth_destroy_hmacs(struct crypto_hash *auth_hmacs[]) | |
496 | { | |
497 | int i; | |
498 | ||
499 | if (!auth_hmacs) | |
500 | return; | |
501 | ||
8d72651d | 502 | for (i = 0; i < SCTP_AUTH_NUM_HMACS; i++) { |
1f485649 VY |
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 | ||
747edc0f | 540 | /* Check the id is in the supported range. And |
541 | * see if we support the id. Supported IDs have name and | |
542 | * length fields set, so that we can allocate and use | |
1f485649 VY |
543 | * them. We can safely just check for name, for without the |
544 | * name, we can't allocate the TFM. | |
545 | */ | |
747edc0f | 546 | if (id > SCTP_AUTH_HMAC_ID_MAX || |
547 | !sctp_hmac_list[id].hmac_name) { | |
51e97a12 | 548 | id = 0; |
1f485649 | 549 | continue; |
51e97a12 | 550 | } |
1f485649 VY |
551 | |
552 | break; | |
553 | } | |
554 | ||
555 | if (id == 0) | |
556 | return NULL; | |
557 | ||
558 | return &sctp_hmac_list[id]; | |
559 | } | |
560 | ||
d06f6082 | 561 | static int __sctp_auth_find_hmacid(__be16 *hmacs, int n_elts, __be16 hmac_id) |
1f485649 VY |
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, | |
d06f6082 | 578 | __be16 hmac_id) |
1f485649 VY |
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 | ||
555d3d5d | 636 | if (!param || param->param_hdr.length == 0) |
1f485649 VY |
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]) { | |
f7010e61 | 649 | case SCTP_CID_INIT: |
650 | case SCTP_CID_INIT_ACK: | |
651 | case SCTP_CID_SHUTDOWN_COMPLETE: | |
652 | case SCTP_CID_AUTH: | |
1f485649 VY |
653 | break; |
654 | ||
f7010e61 | 655 | default: |
1f485649 | 656 | if (param->chunks[i] == chunk) |
f7010e61 | 657 | found = 1; |
1f485649 VY |
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 | { | |
e1fc3b14 EB |
668 | struct net *net; |
669 | if (!asoc) | |
670 | return 0; | |
671 | ||
672 | net = sock_net(asoc->base.sk); | |
673 | if (!net->sctp.auth_enable || !asoc->peer.auth_capable) | |
1f485649 VY |
674 | return 0; |
675 | ||
676 | return __sctp_auth_cid(chunk, asoc->peer.peer_chunks); | |
677 | } | |
678 | ||
679 | /* Check if we requested that peer authenticate this chunk. */ | |
680 | int sctp_auth_recv_cid(sctp_cid_t chunk, const struct sctp_association *asoc) | |
681 | { | |
e1fc3b14 EB |
682 | struct net *net; |
683 | if (!asoc) | |
684 | return 0; | |
685 | ||
686 | net = sock_net(asoc->base.sk); | |
02644a17 | 687 | if (!net->sctp.auth_enable) |
1f485649 VY |
688 | return 0; |
689 | ||
690 | return __sctp_auth_cid(chunk, | |
691 | (struct sctp_chunks_param *)asoc->c.auth_chunks); | |
692 | } | |
693 | ||
694 | /* SCTP-AUTH: Section 6.2: | |
695 | * The sender MUST calculate the MAC as described in RFC2104 [2] using | |
696 | * the hash function H as described by the MAC Identifier and the shared | |
697 | * association key K based on the endpoint pair shared key described by | |
698 | * the shared key identifier. The 'data' used for the computation of | |
699 | * the AUTH-chunk is given by the AUTH chunk with its HMAC field set to | |
700 | * zero (as shown in Figure 6) followed by all chunks that are placed | |
701 | * after the AUTH chunk in the SCTP packet. | |
702 | */ | |
703 | void sctp_auth_calculate_hmac(const struct sctp_association *asoc, | |
704 | struct sk_buff *skb, | |
705 | struct sctp_auth_chunk *auth, | |
706 | gfp_t gfp) | |
707 | { | |
708 | struct scatterlist sg; | |
709 | struct hash_desc desc; | |
710 | struct sctp_auth_bytes *asoc_key; | |
711 | __u16 key_id, hmac_id; | |
712 | __u8 *digest; | |
713 | unsigned char *end; | |
714 | int free_key = 0; | |
715 | ||
716 | /* Extract the info we need: | |
717 | * - hmac id | |
718 | * - key id | |
719 | */ | |
720 | key_id = ntohs(auth->auth_hdr.shkey_id); | |
721 | hmac_id = ntohs(auth->auth_hdr.hmac_id); | |
722 | ||
723 | if (key_id == asoc->active_key_id) | |
724 | asoc_key = asoc->asoc_shared_key; | |
725 | else { | |
726 | struct sctp_shared_key *ep_key; | |
727 | ||
728 | ep_key = sctp_auth_get_shkey(asoc, key_id); | |
729 | if (!ep_key) | |
730 | return; | |
731 | ||
732 | asoc_key = sctp_auth_asoc_create_secret(asoc, ep_key, gfp); | |
733 | if (!asoc_key) | |
734 | return; | |
735 | ||
736 | free_key = 1; | |
737 | } | |
738 | ||
739 | /* set up scatter list */ | |
740 | end = skb_tail_pointer(skb); | |
68e3f5dd | 741 | sg_init_one(&sg, auth, end - (unsigned char *)auth); |
1f485649 VY |
742 | |
743 | desc.tfm = asoc->ep->auth_hmacs[hmac_id]; | |
744 | desc.flags = 0; | |
745 | ||
746 | digest = auth->auth_hdr.hmac; | |
747 | if (crypto_hash_setkey(desc.tfm, &asoc_key->data[0], asoc_key->len)) | |
748 | goto free; | |
749 | ||
750 | crypto_hash_digest(&desc, &sg, sg.length, digest); | |
751 | ||
752 | free: | |
753 | if (free_key) | |
754 | sctp_auth_key_put(asoc_key); | |
755 | } | |
65b07e5d VY |
756 | |
757 | /* API Helpers */ | |
758 | ||
759 | /* Add a chunk to the endpoint authenticated chunk list */ | |
760 | int sctp_auth_ep_add_chunkid(struct sctp_endpoint *ep, __u8 chunk_id) | |
761 | { | |
762 | struct sctp_chunks_param *p = ep->auth_chunk_list; | |
763 | __u16 nchunks; | |
764 | __u16 param_len; | |
765 | ||
766 | /* If this chunk is already specified, we are done */ | |
767 | if (__sctp_auth_cid(chunk_id, p)) | |
768 | return 0; | |
769 | ||
770 | /* Check if we can add this chunk to the array */ | |
771 | param_len = ntohs(p->param_hdr.length); | |
772 | nchunks = param_len - sizeof(sctp_paramhdr_t); | |
773 | if (nchunks == SCTP_NUM_CHUNK_TYPES) | |
774 | return -EINVAL; | |
775 | ||
776 | p->chunks[nchunks] = chunk_id; | |
777 | p->param_hdr.length = htons(param_len + 1); | |
778 | return 0; | |
779 | } | |
780 | ||
781 | /* Add hmac identifires to the endpoint list of supported hmac ids */ | |
782 | int sctp_auth_ep_set_hmacs(struct sctp_endpoint *ep, | |
783 | struct sctp_hmacalgo *hmacs) | |
784 | { | |
785 | int has_sha1 = 0; | |
786 | __u16 id; | |
787 | int i; | |
788 | ||
789 | /* Scan the list looking for unsupported id. Also make sure that | |
790 | * SHA1 is specified. | |
791 | */ | |
792 | for (i = 0; i < hmacs->shmac_num_idents; i++) { | |
793 | id = hmacs->shmac_idents[i]; | |
794 | ||
d9724055 VY |
795 | if (id > SCTP_AUTH_HMAC_ID_MAX) |
796 | return -EOPNOTSUPP; | |
797 | ||
65b07e5d VY |
798 | if (SCTP_AUTH_HMAC_ID_SHA1 == id) |
799 | has_sha1 = 1; | |
800 | ||
801 | if (!sctp_hmac_list[id].hmac_name) | |
802 | return -EOPNOTSUPP; | |
803 | } | |
804 | ||
805 | if (!has_sha1) | |
806 | return -EINVAL; | |
807 | ||
808 | memcpy(ep->auth_hmacs_list->hmac_ids, &hmacs->shmac_idents[0], | |
809 | hmacs->shmac_num_idents * sizeof(__u16)); | |
810 | ep->auth_hmacs_list->param_hdr.length = htons(sizeof(sctp_paramhdr_t) + | |
811 | hmacs->shmac_num_idents * sizeof(__u16)); | |
812 | return 0; | |
813 | } | |
814 | ||
815 | /* Set a new shared key on either endpoint or association. If the | |
816 | * the key with a same ID already exists, replace the key (remove the | |
817 | * old key and add a new one). | |
818 | */ | |
819 | int sctp_auth_set_key(struct sctp_endpoint *ep, | |
820 | struct sctp_association *asoc, | |
821 | struct sctp_authkey *auth_key) | |
822 | { | |
823 | struct sctp_shared_key *cur_key = NULL; | |
824 | struct sctp_auth_bytes *key; | |
825 | struct list_head *sh_keys; | |
826 | int replace = 0; | |
827 | ||
828 | /* Try to find the given key id to see if | |
829 | * we are doing a replace, or adding a new key | |
830 | */ | |
831 | if (asoc) | |
832 | sh_keys = &asoc->endpoint_shared_keys; | |
833 | else | |
834 | sh_keys = &ep->endpoint_shared_keys; | |
835 | ||
836 | key_for_each(cur_key, sh_keys) { | |
837 | if (cur_key->key_id == auth_key->sca_keynumber) { | |
838 | replace = 1; | |
839 | break; | |
840 | } | |
841 | } | |
842 | ||
843 | /* If we are not replacing a key id, we need to allocate | |
844 | * a shared key. | |
845 | */ | |
846 | if (!replace) { | |
847 | cur_key = sctp_auth_shkey_create(auth_key->sca_keynumber, | |
848 | GFP_KERNEL); | |
849 | if (!cur_key) | |
850 | return -ENOMEM; | |
851 | } | |
852 | ||
853 | /* Create a new key data based on the info passed in */ | |
7e8616d8 | 854 | key = sctp_auth_create_key(auth_key->sca_keylength, GFP_KERNEL); |
65b07e5d VY |
855 | if (!key) |
856 | goto nomem; | |
857 | ||
7e8616d8 | 858 | memcpy(key->data, &auth_key->sca_key[0], auth_key->sca_keylength); |
65b07e5d VY |
859 | |
860 | /* If we are replacing, remove the old keys data from the | |
861 | * key id. If we are adding new key id, add it to the | |
862 | * list. | |
863 | */ | |
864 | if (replace) | |
865 | sctp_auth_key_put(cur_key->key); | |
866 | else | |
867 | list_add(&cur_key->key_list, sh_keys); | |
868 | ||
869 | cur_key->key = key; | |
870 | sctp_auth_key_hold(key); | |
871 | ||
872 | return 0; | |
873 | nomem: | |
874 | if (!replace) | |
875 | sctp_auth_shkey_free(cur_key); | |
876 | ||
877 | return -ENOMEM; | |
878 | } | |
879 | ||
880 | int sctp_auth_set_active_key(struct sctp_endpoint *ep, | |
881 | struct sctp_association *asoc, | |
882 | __u16 key_id) | |
883 | { | |
884 | struct sctp_shared_key *key; | |
885 | struct list_head *sh_keys; | |
886 | int found = 0; | |
887 | ||
888 | /* The key identifier MUST correst to an existing key */ | |
889 | if (asoc) | |
890 | sh_keys = &asoc->endpoint_shared_keys; | |
891 | else | |
892 | sh_keys = &ep->endpoint_shared_keys; | |
893 | ||
894 | key_for_each(key, sh_keys) { | |
895 | if (key->key_id == key_id) { | |
896 | found = 1; | |
897 | break; | |
898 | } | |
899 | } | |
900 | ||
901 | if (!found) | |
902 | return -EINVAL; | |
903 | ||
904 | if (asoc) { | |
905 | asoc->active_key_id = key_id; | |
906 | sctp_auth_asoc_init_active_key(asoc, GFP_KERNEL); | |
907 | } else | |
908 | ep->active_key_id = key_id; | |
909 | ||
910 | return 0; | |
911 | } | |
912 | ||
913 | int sctp_auth_del_key_id(struct sctp_endpoint *ep, | |
914 | struct sctp_association *asoc, | |
915 | __u16 key_id) | |
916 | { | |
917 | struct sctp_shared_key *key; | |
918 | struct list_head *sh_keys; | |
919 | int found = 0; | |
920 | ||
921 | /* The key identifier MUST NOT be the current active key | |
922 | * The key identifier MUST correst to an existing key | |
923 | */ | |
924 | if (asoc) { | |
925 | if (asoc->active_key_id == key_id) | |
926 | return -EINVAL; | |
927 | ||
928 | sh_keys = &asoc->endpoint_shared_keys; | |
929 | } else { | |
930 | if (ep->active_key_id == key_id) | |
931 | return -EINVAL; | |
932 | ||
933 | sh_keys = &ep->endpoint_shared_keys; | |
934 | } | |
935 | ||
936 | key_for_each(key, sh_keys) { | |
937 | if (key->key_id == key_id) { | |
938 | found = 1; | |
939 | break; | |
940 | } | |
941 | } | |
942 | ||
943 | if (!found) | |
944 | return -EINVAL; | |
945 | ||
946 | /* Delete the shared key */ | |
947 | list_del_init(&key->key_list); | |
948 | sctp_auth_shkey_free(key); | |
949 | ||
950 | return 0; | |
951 | } |