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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 | |
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 | ||
5a0e3ad6 | 37 | #include <linux/slab.h> |
1f485649 VY |
38 | #include <linux/types.h> |
39 | #include <linux/crypto.h> | |
40 | #include <linux/scatterlist.h> | |
41 | #include <net/sctp/sctp.h> | |
42 | #include <net/sctp/auth.h> | |
43 | ||
44 | static struct sctp_hmac sctp_hmac_list[SCTP_AUTH_NUM_HMACS] = { | |
45 | { | |
46 | /* id 0 is reserved. as all 0 */ | |
47 | .hmac_id = SCTP_AUTH_HMAC_ID_RESERVED_0, | |
48 | }, | |
49 | { | |
50 | .hmac_id = SCTP_AUTH_HMAC_ID_SHA1, | |
51 | .hmac_name="hmac(sha1)", | |
52 | .hmac_len = SCTP_SHA1_SIG_SIZE, | |
53 | }, | |
54 | { | |
55 | /* id 2 is reserved as well */ | |
56 | .hmac_id = SCTP_AUTH_HMAC_ID_RESERVED_2, | |
57 | }, | |
b7e0fe9f | 58 | #if defined (CONFIG_CRYPTO_SHA256) || defined (CONFIG_CRYPTO_SHA256_MODULE) |
1f485649 VY |
59 | { |
60 | .hmac_id = SCTP_AUTH_HMAC_ID_SHA256, | |
61 | .hmac_name="hmac(sha256)", | |
62 | .hmac_len = SCTP_SHA256_SIG_SIZE, | |
63 | } | |
b7e0fe9f | 64 | #endif |
1f485649 VY |
65 | }; |
66 | ||
67 | ||
68 | void sctp_auth_key_put(struct sctp_auth_bytes *key) | |
69 | { | |
70 | if (!key) | |
71 | return; | |
72 | ||
73 | if (atomic_dec_and_test(&key->refcnt)) { | |
74 | kfree(key); | |
75 | SCTP_DBG_OBJCNT_DEC(keys); | |
76 | } | |
77 | } | |
78 | ||
79 | /* Create a new key structure of a given length */ | |
80 | static struct sctp_auth_bytes *sctp_auth_create_key(__u32 key_len, gfp_t gfp) | |
81 | { | |
82 | struct sctp_auth_bytes *key; | |
83 | ||
30c2235c VY |
84 | /* Verify that we are not going to overflow INT_MAX */ |
85 | if ((INT_MAX - key_len) < sizeof(struct sctp_auth_bytes)) | |
86 | return NULL; | |
87 | ||
1f485649 VY |
88 | /* Allocate the shared key */ |
89 | key = kmalloc(sizeof(struct sctp_auth_bytes) + key_len, gfp); | |
90 | if (!key) | |
91 | return NULL; | |
92 | ||
93 | key->len = key_len; | |
94 | atomic_set(&key->refcnt, 1); | |
95 | SCTP_DBG_OBJCNT_INC(keys); | |
96 | ||
97 | return key; | |
98 | } | |
99 | ||
100 | /* Create a new shared key container with a give key id */ | |
101 | struct sctp_shared_key *sctp_auth_shkey_create(__u16 key_id, gfp_t gfp) | |
102 | { | |
103 | struct sctp_shared_key *new; | |
104 | ||
105 | /* Allocate the shared key container */ | |
106 | new = kzalloc(sizeof(struct sctp_shared_key), gfp); | |
107 | if (!new) | |
108 | return NULL; | |
109 | ||
110 | INIT_LIST_HEAD(&new->key_list); | |
111 | new->key_id = key_id; | |
112 | ||
113 | return new; | |
114 | } | |
115 | ||
25985edc | 116 | /* Free the shared key structure */ |
8ad7c62b | 117 | static void sctp_auth_shkey_free(struct sctp_shared_key *sh_key) |
1f485649 VY |
118 | { |
119 | BUG_ON(!list_empty(&sh_key->key_list)); | |
120 | sctp_auth_key_put(sh_key->key); | |
121 | sh_key->key = NULL; | |
122 | kfree(sh_key); | |
123 | } | |
124 | ||
25985edc | 125 | /* Destroy the entire key list. This is done during the |
1f485649 VY |
126 | * associon and endpoint free process. |
127 | */ | |
128 | void sctp_auth_destroy_keys(struct list_head *keys) | |
129 | { | |
130 | struct sctp_shared_key *ep_key; | |
131 | struct sctp_shared_key *tmp; | |
132 | ||
133 | if (list_empty(keys)) | |
134 | return; | |
135 | ||
136 | key_for_each_safe(ep_key, tmp, keys) { | |
137 | list_del_init(&ep_key->key_list); | |
138 | sctp_auth_shkey_free(ep_key); | |
139 | } | |
140 | } | |
141 | ||
142 | /* Compare two byte vectors as numbers. Return values | |
143 | * are: | |
144 | * 0 - vectors are equal | |
025dfdaf FS |
145 | * < 0 - vector 1 is smaller than vector2 |
146 | * > 0 - vector 1 is greater than vector2 | |
1f485649 VY |
147 | * |
148 | * Algorithm is: | |
149 | * This is performed by selecting the numerically smaller key vector... | |
150 | * If the key vectors are equal as numbers but differ in length ... | |
151 | * the shorter vector is considered smaller | |
152 | * | |
153 | * Examples (with small values): | |
154 | * 000123456789 > 123456789 (first number is longer) | |
155 | * 000123456789 < 234567891 (second number is larger numerically) | |
156 | * 123456789 > 2345678 (first number is both larger & longer) | |
157 | */ | |
158 | static int sctp_auth_compare_vectors(struct sctp_auth_bytes *vector1, | |
159 | struct sctp_auth_bytes *vector2) | |
160 | { | |
161 | int diff; | |
162 | int i; | |
163 | const __u8 *longer; | |
164 | ||
165 | diff = vector1->len - vector2->len; | |
166 | if (diff) { | |
167 | longer = (diff > 0) ? vector1->data : vector2->data; | |
168 | ||
169 | /* Check to see if the longer number is | |
170 | * lead-zero padded. If it is not, it | |
171 | * is automatically larger numerically. | |
172 | */ | |
173 | for (i = 0; i < abs(diff); i++ ) { | |
174 | if (longer[i] != 0) | |
175 | return diff; | |
176 | } | |
177 | } | |
178 | ||
179 | /* lengths are the same, compare numbers */ | |
180 | return memcmp(vector1->data, vector2->data, vector1->len); | |
181 | } | |
182 | ||
183 | /* | |
184 | * Create a key vector as described in SCTP-AUTH, Section 6.1 | |
185 | * The RANDOM parameter, the CHUNKS parameter and the HMAC-ALGO | |
186 | * parameter sent by each endpoint are concatenated as byte vectors. | |
187 | * These parameters include the parameter type, parameter length, and | |
188 | * the parameter value, but padding is omitted; all padding MUST be | |
189 | * removed from this concatenation before proceeding with further | |
190 | * computation of keys. Parameters which were not sent are simply | |
191 | * omitted from the concatenation process. The resulting two vectors | |
192 | * are called the two key vectors. | |
193 | */ | |
194 | static struct sctp_auth_bytes *sctp_auth_make_key_vector( | |
195 | sctp_random_param_t *random, | |
196 | sctp_chunks_param_t *chunks, | |
197 | sctp_hmac_algo_param_t *hmacs, | |
198 | gfp_t gfp) | |
199 | { | |
200 | struct sctp_auth_bytes *new; | |
201 | __u32 len; | |
202 | __u32 offset = 0; | |
203 | ||
204 | len = ntohs(random->param_hdr.length) + ntohs(hmacs->param_hdr.length); | |
205 | if (chunks) | |
206 | len += ntohs(chunks->param_hdr.length); | |
207 | ||
208 | new = kmalloc(sizeof(struct sctp_auth_bytes) + len, gfp); | |
209 | if (!new) | |
210 | return NULL; | |
211 | ||
212 | new->len = len; | |
213 | ||
214 | memcpy(new->data, random, ntohs(random->param_hdr.length)); | |
215 | offset += ntohs(random->param_hdr.length); | |
216 | ||
217 | if (chunks) { | |
218 | memcpy(new->data + offset, chunks, | |
219 | ntohs(chunks->param_hdr.length)); | |
220 | offset += ntohs(chunks->param_hdr.length); | |
221 | } | |
222 | ||
223 | memcpy(new->data + offset, hmacs, ntohs(hmacs->param_hdr.length)); | |
224 | ||
225 | return new; | |
226 | } | |
227 | ||
228 | ||
229 | /* Make a key vector based on our local parameters */ | |
8ad7c62b | 230 | static struct sctp_auth_bytes *sctp_auth_make_local_vector( |
1f485649 VY |
231 | const struct sctp_association *asoc, |
232 | gfp_t gfp) | |
233 | { | |
234 | return sctp_auth_make_key_vector( | |
235 | (sctp_random_param_t*)asoc->c.auth_random, | |
236 | (sctp_chunks_param_t*)asoc->c.auth_chunks, | |
237 | (sctp_hmac_algo_param_t*)asoc->c.auth_hmacs, | |
238 | gfp); | |
239 | } | |
240 | ||
241 | /* Make a key vector based on peer's parameters */ | |
8ad7c62b | 242 | static struct sctp_auth_bytes *sctp_auth_make_peer_vector( |
1f485649 VY |
243 | const struct sctp_association *asoc, |
244 | gfp_t gfp) | |
245 | { | |
246 | return sctp_auth_make_key_vector(asoc->peer.peer_random, | |
247 | asoc->peer.peer_chunks, | |
248 | asoc->peer.peer_hmacs, | |
249 | gfp); | |
250 | } | |
251 | ||
252 | ||
253 | /* Set the value of the association shared key base on the parameters | |
254 | * given. The algorithm is: | |
255 | * From the endpoint pair shared keys and the key vectors the | |
256 | * association shared keys are computed. This is performed by selecting | |
257 | * the numerically smaller key vector and concatenating it to the | |
258 | * endpoint pair shared key, and then concatenating the numerically | |
259 | * larger key vector to that. The result of the concatenation is the | |
260 | * association shared key. | |
261 | */ | |
262 | static struct sctp_auth_bytes *sctp_auth_asoc_set_secret( | |
263 | struct sctp_shared_key *ep_key, | |
264 | struct sctp_auth_bytes *first_vector, | |
265 | struct sctp_auth_bytes *last_vector, | |
266 | gfp_t gfp) | |
267 | { | |
268 | struct sctp_auth_bytes *secret; | |
269 | __u32 offset = 0; | |
270 | __u32 auth_len; | |
271 | ||
272 | auth_len = first_vector->len + last_vector->len; | |
273 | if (ep_key->key) | |
274 | auth_len += ep_key->key->len; | |
275 | ||
276 | secret = sctp_auth_create_key(auth_len, gfp); | |
277 | if (!secret) | |
278 | return NULL; | |
279 | ||
280 | if (ep_key->key) { | |
281 | memcpy(secret->data, ep_key->key->data, ep_key->key->len); | |
282 | offset += ep_key->key->len; | |
283 | } | |
284 | ||
285 | memcpy(secret->data + offset, first_vector->data, first_vector->len); | |
286 | offset += first_vector->len; | |
287 | ||
288 | memcpy(secret->data + offset, last_vector->data, last_vector->len); | |
289 | ||
290 | return secret; | |
291 | } | |
292 | ||
293 | /* Create an association shared key. Follow the algorithm | |
294 | * described in SCTP-AUTH, Section 6.1 | |
295 | */ | |
296 | static struct sctp_auth_bytes *sctp_auth_asoc_create_secret( | |
297 | const struct sctp_association *asoc, | |
298 | struct sctp_shared_key *ep_key, | |
299 | gfp_t gfp) | |
300 | { | |
301 | struct sctp_auth_bytes *local_key_vector; | |
302 | struct sctp_auth_bytes *peer_key_vector; | |
303 | struct sctp_auth_bytes *first_vector, | |
304 | *last_vector; | |
305 | struct sctp_auth_bytes *secret = NULL; | |
306 | int cmp; | |
307 | ||
308 | ||
309 | /* Now we need to build the key vectors | |
310 | * SCTP-AUTH , Section 6.1 | |
311 | * The RANDOM parameter, the CHUNKS parameter and the HMAC-ALGO | |
312 | * parameter sent by each endpoint are concatenated as byte vectors. | |
313 | * These parameters include the parameter type, parameter length, and | |
314 | * the parameter value, but padding is omitted; all padding MUST be | |
315 | * removed from this concatenation before proceeding with further | |
316 | * computation of keys. Parameters which were not sent are simply | |
317 | * omitted from the concatenation process. The resulting two vectors | |
318 | * are called the two key vectors. | |
319 | */ | |
320 | ||
321 | local_key_vector = sctp_auth_make_local_vector(asoc, gfp); | |
322 | peer_key_vector = sctp_auth_make_peer_vector(asoc, gfp); | |
323 | ||
324 | if (!peer_key_vector || !local_key_vector) | |
325 | goto out; | |
326 | ||
25985edc | 327 | /* Figure out the order in which the key_vectors will be |
1f485649 VY |
328 | * added to the endpoint shared key. |
329 | * SCTP-AUTH, Section 6.1: | |
330 | * This is performed by selecting the numerically smaller key | |
331 | * vector and concatenating it to the endpoint pair shared | |
332 | * key, and then concatenating the numerically larger key | |
333 | * vector to that. If the key vectors are equal as numbers | |
334 | * but differ in length, then the concatenation order is the | |
335 | * endpoint shared key, followed by the shorter key vector, | |
336 | * followed by the longer key vector. Otherwise, the key | |
337 | * vectors are identical, and may be concatenated to the | |
338 | * endpoint pair key in any order. | |
339 | */ | |
340 | cmp = sctp_auth_compare_vectors(local_key_vector, | |
341 | peer_key_vector); | |
342 | if (cmp < 0) { | |
343 | first_vector = local_key_vector; | |
344 | last_vector = peer_key_vector; | |
345 | } else { | |
346 | first_vector = peer_key_vector; | |
347 | last_vector = local_key_vector; | |
348 | } | |
349 | ||
350 | secret = sctp_auth_asoc_set_secret(ep_key, first_vector, last_vector, | |
351 | gfp); | |
352 | out: | |
353 | kfree(local_key_vector); | |
354 | kfree(peer_key_vector); | |
355 | ||
356 | return secret; | |
357 | } | |
358 | ||
359 | /* | |
360 | * Populate the association overlay list with the list | |
361 | * from the endpoint. | |
362 | */ | |
363 | int sctp_auth_asoc_copy_shkeys(const struct sctp_endpoint *ep, | |
364 | struct sctp_association *asoc, | |
365 | gfp_t gfp) | |
366 | { | |
367 | struct sctp_shared_key *sh_key; | |
368 | struct sctp_shared_key *new; | |
369 | ||
370 | BUG_ON(!list_empty(&asoc->endpoint_shared_keys)); | |
371 | ||
372 | key_for_each(sh_key, &ep->endpoint_shared_keys) { | |
373 | new = sctp_auth_shkey_create(sh_key->key_id, gfp); | |
374 | if (!new) | |
375 | goto nomem; | |
376 | ||
377 | new->key = sh_key->key; | |
378 | sctp_auth_key_hold(new->key); | |
379 | list_add(&new->key_list, &asoc->endpoint_shared_keys); | |
380 | } | |
381 | ||
382 | return 0; | |
383 | ||
384 | nomem: | |
385 | sctp_auth_destroy_keys(&asoc->endpoint_shared_keys); | |
386 | return -ENOMEM; | |
387 | } | |
388 | ||
389 | ||
390 | /* Public interface to creat the association shared key. | |
391 | * See code above for the algorithm. | |
392 | */ | |
393 | int sctp_auth_asoc_init_active_key(struct sctp_association *asoc, gfp_t gfp) | |
394 | { | |
395 | struct sctp_auth_bytes *secret; | |
396 | struct sctp_shared_key *ep_key; | |
397 | ||
398 | /* If we don't support AUTH, or peer is not capable | |
399 | * we don't need to do anything. | |
400 | */ | |
401 | if (!sctp_auth_enable || !asoc->peer.auth_capable) | |
402 | return 0; | |
403 | ||
404 | /* If the key_id is non-zero and we couldn't find an | |
405 | * endpoint pair shared key, we can't compute the | |
406 | * secret. | |
407 | * For key_id 0, endpoint pair shared key is a NULL key. | |
408 | */ | |
409 | ep_key = sctp_auth_get_shkey(asoc, asoc->active_key_id); | |
410 | BUG_ON(!ep_key); | |
411 | ||
412 | secret = sctp_auth_asoc_create_secret(asoc, ep_key, gfp); | |
413 | if (!secret) | |
414 | return -ENOMEM; | |
415 | ||
416 | sctp_auth_key_put(asoc->asoc_shared_key); | |
417 | asoc->asoc_shared_key = secret; | |
418 | ||
419 | return 0; | |
420 | } | |
421 | ||
422 | ||
423 | /* Find the endpoint pair shared key based on the key_id */ | |
424 | struct sctp_shared_key *sctp_auth_get_shkey( | |
425 | const struct sctp_association *asoc, | |
426 | __u16 key_id) | |
427 | { | |
7cc08b55 | 428 | struct sctp_shared_key *key; |
1f485649 VY |
429 | |
430 | /* First search associations set of endpoint pair shared keys */ | |
431 | key_for_each(key, &asoc->endpoint_shared_keys) { | |
432 | if (key->key_id == key_id) | |
7cc08b55 | 433 | return key; |
1f485649 VY |
434 | } |
435 | ||
7cc08b55 | 436 | return NULL; |
1f485649 VY |
437 | } |
438 | ||
439 | /* | |
440 | * Initialize all the possible digest transforms that we can use. Right now | |
441 | * now, the supported digests are SHA1 and SHA256. We do this here once | |
442 | * because of the restrictiong that transforms may only be allocated in | |
443 | * user context. This forces us to pre-allocated all possible transforms | |
444 | * at the endpoint init time. | |
445 | */ | |
446 | int sctp_auth_init_hmacs(struct sctp_endpoint *ep, gfp_t gfp) | |
447 | { | |
448 | struct crypto_hash *tfm = NULL; | |
449 | __u16 id; | |
450 | ||
451 | /* if the transforms are already allocted, we are done */ | |
452 | if (!sctp_auth_enable) { | |
453 | ep->auth_hmacs = NULL; | |
454 | return 0; | |
455 | } | |
456 | ||
457 | if (ep->auth_hmacs) | |
458 | return 0; | |
459 | ||
460 | /* Allocated the array of pointers to transorms */ | |
461 | ep->auth_hmacs = kzalloc( | |
462 | sizeof(struct crypto_hash *) * SCTP_AUTH_NUM_HMACS, | |
463 | gfp); | |
464 | if (!ep->auth_hmacs) | |
465 | return -ENOMEM; | |
466 | ||
467 | for (id = 0; id < SCTP_AUTH_NUM_HMACS; id++) { | |
468 | ||
469 | /* See is we support the id. Supported IDs have name and | |
470 | * length fields set, so that we can allocated and use | |
471 | * them. We can safely just check for name, for without the | |
472 | * name, we can't allocate the TFM. | |
473 | */ | |
474 | if (!sctp_hmac_list[id].hmac_name) | |
475 | continue; | |
476 | ||
477 | /* If this TFM has been allocated, we are all set */ | |
478 | if (ep->auth_hmacs[id]) | |
479 | continue; | |
480 | ||
481 | /* Allocate the ID */ | |
482 | tfm = crypto_alloc_hash(sctp_hmac_list[id].hmac_name, 0, | |
483 | CRYPTO_ALG_ASYNC); | |
484 | if (IS_ERR(tfm)) | |
485 | goto out_err; | |
486 | ||
487 | ep->auth_hmacs[id] = tfm; | |
488 | } | |
489 | ||
490 | return 0; | |
491 | ||
492 | out_err: | |
73ac36ea | 493 | /* Clean up any successful allocations */ |
1f485649 VY |
494 | sctp_auth_destroy_hmacs(ep->auth_hmacs); |
495 | return -ENOMEM; | |
496 | } | |
497 | ||
498 | /* Destroy the hmac tfm array */ | |
499 | void sctp_auth_destroy_hmacs(struct crypto_hash *auth_hmacs[]) | |
500 | { | |
501 | int i; | |
502 | ||
503 | if (!auth_hmacs) | |
504 | return; | |
505 | ||
506 | for (i = 0; i < SCTP_AUTH_NUM_HMACS; i++) | |
507 | { | |
508 | if (auth_hmacs[i]) | |
509 | crypto_free_hash(auth_hmacs[i]); | |
510 | } | |
511 | kfree(auth_hmacs); | |
512 | } | |
513 | ||
514 | ||
515 | struct sctp_hmac *sctp_auth_get_hmac(__u16 hmac_id) | |
516 | { | |
517 | return &sctp_hmac_list[hmac_id]; | |
518 | } | |
519 | ||
520 | /* Get an hmac description information that we can use to build | |
521 | * the AUTH chunk | |
522 | */ | |
523 | struct sctp_hmac *sctp_auth_asoc_get_hmac(const struct sctp_association *asoc) | |
524 | { | |
525 | struct sctp_hmac_algo_param *hmacs; | |
526 | __u16 n_elt; | |
527 | __u16 id = 0; | |
528 | int i; | |
529 | ||
530 | /* If we have a default entry, use it */ | |
531 | if (asoc->default_hmac_id) | |
532 | return &sctp_hmac_list[asoc->default_hmac_id]; | |
533 | ||
534 | /* Since we do not have a default entry, find the first entry | |
535 | * we support and return that. Do not cache that id. | |
536 | */ | |
537 | hmacs = asoc->peer.peer_hmacs; | |
538 | if (!hmacs) | |
539 | return NULL; | |
540 | ||
541 | n_elt = (ntohs(hmacs->param_hdr.length) - sizeof(sctp_paramhdr_t)) >> 1; | |
542 | for (i = 0; i < n_elt; i++) { | |
543 | id = ntohs(hmacs->hmac_ids[i]); | |
544 | ||
545 | /* Check the id is in the supported range */ | |
51e97a12 DR |
546 | if (id > SCTP_AUTH_HMAC_ID_MAX) { |
547 | id = 0; | |
1f485649 | 548 | continue; |
51e97a12 | 549 | } |
1f485649 VY |
550 | |
551 | /* See is we support the id. Supported IDs have name and | |
552 | * length fields set, so that we can allocated and use | |
553 | * them. We can safely just check for name, for without the | |
554 | * name, we can't allocate the TFM. | |
555 | */ | |
51e97a12 DR |
556 | if (!sctp_hmac_list[id].hmac_name) { |
557 | id = 0; | |
1f485649 | 558 | continue; |
51e97a12 | 559 | } |
1f485649 VY |
560 | |
561 | break; | |
562 | } | |
563 | ||
564 | if (id == 0) | |
565 | return NULL; | |
566 | ||
567 | return &sctp_hmac_list[id]; | |
568 | } | |
569 | ||
d06f6082 | 570 | static int __sctp_auth_find_hmacid(__be16 *hmacs, int n_elts, __be16 hmac_id) |
1f485649 VY |
571 | { |
572 | int found = 0; | |
573 | int i; | |
574 | ||
575 | for (i = 0; i < n_elts; i++) { | |
576 | if (hmac_id == hmacs[i]) { | |
577 | found = 1; | |
578 | break; | |
579 | } | |
580 | } | |
581 | ||
582 | return found; | |
583 | } | |
584 | ||
585 | /* See if the HMAC_ID is one that we claim as supported */ | |
586 | int sctp_auth_asoc_verify_hmac_id(const struct sctp_association *asoc, | |
d06f6082 | 587 | __be16 hmac_id) |
1f485649 VY |
588 | { |
589 | struct sctp_hmac_algo_param *hmacs; | |
590 | __u16 n_elt; | |
591 | ||
592 | if (!asoc) | |
593 | return 0; | |
594 | ||
595 | hmacs = (struct sctp_hmac_algo_param *)asoc->c.auth_hmacs; | |
596 | n_elt = (ntohs(hmacs->param_hdr.length) - sizeof(sctp_paramhdr_t)) >> 1; | |
597 | ||
598 | return __sctp_auth_find_hmacid(hmacs->hmac_ids, n_elt, hmac_id); | |
599 | } | |
600 | ||
601 | ||
602 | /* Cache the default HMAC id. This to follow this text from SCTP-AUTH: | |
603 | * Section 6.1: | |
604 | * The receiver of a HMAC-ALGO parameter SHOULD use the first listed | |
605 | * algorithm it supports. | |
606 | */ | |
607 | void sctp_auth_asoc_set_default_hmac(struct sctp_association *asoc, | |
608 | struct sctp_hmac_algo_param *hmacs) | |
609 | { | |
610 | struct sctp_endpoint *ep; | |
611 | __u16 id; | |
612 | int i; | |
613 | int n_params; | |
614 | ||
615 | /* if the default id is already set, use it */ | |
616 | if (asoc->default_hmac_id) | |
617 | return; | |
618 | ||
619 | n_params = (ntohs(hmacs->param_hdr.length) | |
620 | - sizeof(sctp_paramhdr_t)) >> 1; | |
621 | ep = asoc->ep; | |
622 | for (i = 0; i < n_params; i++) { | |
623 | id = ntohs(hmacs->hmac_ids[i]); | |
624 | ||
625 | /* Check the id is in the supported range */ | |
626 | if (id > SCTP_AUTH_HMAC_ID_MAX) | |
627 | continue; | |
628 | ||
629 | /* If this TFM has been allocated, use this id */ | |
630 | if (ep->auth_hmacs[id]) { | |
631 | asoc->default_hmac_id = id; | |
632 | break; | |
633 | } | |
634 | } | |
635 | } | |
636 | ||
637 | ||
638 | /* Check to see if the given chunk is supposed to be authenticated */ | |
639 | static int __sctp_auth_cid(sctp_cid_t chunk, struct sctp_chunks_param *param) | |
640 | { | |
641 | unsigned short len; | |
642 | int found = 0; | |
643 | int i; | |
644 | ||
555d3d5d | 645 | if (!param || param->param_hdr.length == 0) |
1f485649 VY |
646 | return 0; |
647 | ||
648 | len = ntohs(param->param_hdr.length) - sizeof(sctp_paramhdr_t); | |
649 | ||
650 | /* SCTP-AUTH, Section 3.2 | |
651 | * The chunk types for INIT, INIT-ACK, SHUTDOWN-COMPLETE and AUTH | |
652 | * chunks MUST NOT be listed in the CHUNKS parameter. However, if | |
653 | * a CHUNKS parameter is received then the types for INIT, INIT-ACK, | |
654 | * SHUTDOWN-COMPLETE and AUTH chunks MUST be ignored. | |
655 | */ | |
656 | for (i = 0; !found && i < len; i++) { | |
657 | switch (param->chunks[i]) { | |
658 | case SCTP_CID_INIT: | |
659 | case SCTP_CID_INIT_ACK: | |
660 | case SCTP_CID_SHUTDOWN_COMPLETE: | |
661 | case SCTP_CID_AUTH: | |
662 | break; | |
663 | ||
664 | default: | |
665 | if (param->chunks[i] == chunk) | |
666 | found = 1; | |
667 | break; | |
668 | } | |
669 | } | |
670 | ||
671 | return found; | |
672 | } | |
673 | ||
674 | /* Check if peer requested that this chunk is authenticated */ | |
675 | int sctp_auth_send_cid(sctp_cid_t chunk, const struct sctp_association *asoc) | |
676 | { | |
677 | if (!sctp_auth_enable || !asoc || !asoc->peer.auth_capable) | |
678 | return 0; | |
679 | ||
680 | return __sctp_auth_cid(chunk, asoc->peer.peer_chunks); | |
681 | } | |
682 | ||
683 | /* Check if we requested that peer authenticate this chunk. */ | |
684 | int sctp_auth_recv_cid(sctp_cid_t chunk, const struct sctp_association *asoc) | |
685 | { | |
686 | if (!sctp_auth_enable || !asoc) | |
687 | return 0; | |
688 | ||
689 | return __sctp_auth_cid(chunk, | |
690 | (struct sctp_chunks_param *)asoc->c.auth_chunks); | |
691 | } | |
692 | ||
693 | /* SCTP-AUTH: Section 6.2: | |
694 | * The sender MUST calculate the MAC as described in RFC2104 [2] using | |
695 | * the hash function H as described by the MAC Identifier and the shared | |
696 | * association key K based on the endpoint pair shared key described by | |
697 | * the shared key identifier. The 'data' used for the computation of | |
698 | * the AUTH-chunk is given by the AUTH chunk with its HMAC field set to | |
699 | * zero (as shown in Figure 6) followed by all chunks that are placed | |
700 | * after the AUTH chunk in the SCTP packet. | |
701 | */ | |
702 | void sctp_auth_calculate_hmac(const struct sctp_association *asoc, | |
703 | struct sk_buff *skb, | |
704 | struct sctp_auth_chunk *auth, | |
705 | gfp_t gfp) | |
706 | { | |
707 | struct scatterlist sg; | |
708 | struct hash_desc desc; | |
709 | struct sctp_auth_bytes *asoc_key; | |
710 | __u16 key_id, hmac_id; | |
711 | __u8 *digest; | |
712 | unsigned char *end; | |
713 | int free_key = 0; | |
714 | ||
715 | /* Extract the info we need: | |
716 | * - hmac id | |
717 | * - key id | |
718 | */ | |
719 | key_id = ntohs(auth->auth_hdr.shkey_id); | |
720 | hmac_id = ntohs(auth->auth_hdr.hmac_id); | |
721 | ||
722 | if (key_id == asoc->active_key_id) | |
723 | asoc_key = asoc->asoc_shared_key; | |
724 | else { | |
725 | struct sctp_shared_key *ep_key; | |
726 | ||
727 | ep_key = sctp_auth_get_shkey(asoc, key_id); | |
728 | if (!ep_key) | |
729 | return; | |
730 | ||
731 | asoc_key = sctp_auth_asoc_create_secret(asoc, ep_key, gfp); | |
732 | if (!asoc_key) | |
733 | return; | |
734 | ||
735 | free_key = 1; | |
736 | } | |
737 | ||
738 | /* set up scatter list */ | |
739 | end = skb_tail_pointer(skb); | |
68e3f5dd | 740 | sg_init_one(&sg, auth, end - (unsigned char *)auth); |
1f485649 VY |
741 | |
742 | desc.tfm = asoc->ep->auth_hmacs[hmac_id]; | |
743 | desc.flags = 0; | |
744 | ||
745 | digest = auth->auth_hdr.hmac; | |
746 | if (crypto_hash_setkey(desc.tfm, &asoc_key->data[0], asoc_key->len)) | |
747 | goto free; | |
748 | ||
749 | crypto_hash_digest(&desc, &sg, sg.length, digest); | |
750 | ||
751 | free: | |
752 | if (free_key) | |
753 | sctp_auth_key_put(asoc_key); | |
754 | } | |
65b07e5d VY |
755 | |
756 | /* API Helpers */ | |
757 | ||
758 | /* Add a chunk to the endpoint authenticated chunk list */ | |
759 | int sctp_auth_ep_add_chunkid(struct sctp_endpoint *ep, __u8 chunk_id) | |
760 | { | |
761 | struct sctp_chunks_param *p = ep->auth_chunk_list; | |
762 | __u16 nchunks; | |
763 | __u16 param_len; | |
764 | ||
765 | /* If this chunk is already specified, we are done */ | |
766 | if (__sctp_auth_cid(chunk_id, p)) | |
767 | return 0; | |
768 | ||
769 | /* Check if we can add this chunk to the array */ | |
770 | param_len = ntohs(p->param_hdr.length); | |
771 | nchunks = param_len - sizeof(sctp_paramhdr_t); | |
772 | if (nchunks == SCTP_NUM_CHUNK_TYPES) | |
773 | return -EINVAL; | |
774 | ||
775 | p->chunks[nchunks] = chunk_id; | |
776 | p->param_hdr.length = htons(param_len + 1); | |
777 | return 0; | |
778 | } | |
779 | ||
780 | /* Add hmac identifires to the endpoint list of supported hmac ids */ | |
781 | int sctp_auth_ep_set_hmacs(struct sctp_endpoint *ep, | |
782 | struct sctp_hmacalgo *hmacs) | |
783 | { | |
784 | int has_sha1 = 0; | |
785 | __u16 id; | |
786 | int i; | |
787 | ||
788 | /* Scan the list looking for unsupported id. Also make sure that | |
789 | * SHA1 is specified. | |
790 | */ | |
791 | for (i = 0; i < hmacs->shmac_num_idents; i++) { | |
792 | id = hmacs->shmac_idents[i]; | |
793 | ||
d9724055 VY |
794 | if (id > SCTP_AUTH_HMAC_ID_MAX) |
795 | return -EOPNOTSUPP; | |
796 | ||
65b07e5d VY |
797 | if (SCTP_AUTH_HMAC_ID_SHA1 == id) |
798 | has_sha1 = 1; | |
799 | ||
800 | if (!sctp_hmac_list[id].hmac_name) | |
801 | return -EOPNOTSUPP; | |
802 | } | |
803 | ||
804 | if (!has_sha1) | |
805 | return -EINVAL; | |
806 | ||
807 | memcpy(ep->auth_hmacs_list->hmac_ids, &hmacs->shmac_idents[0], | |
808 | hmacs->shmac_num_idents * sizeof(__u16)); | |
809 | ep->auth_hmacs_list->param_hdr.length = htons(sizeof(sctp_paramhdr_t) + | |
810 | hmacs->shmac_num_idents * sizeof(__u16)); | |
811 | return 0; | |
812 | } | |
813 | ||
814 | /* Set a new shared key on either endpoint or association. If the | |
815 | * the key with a same ID already exists, replace the key (remove the | |
816 | * old key and add a new one). | |
817 | */ | |
818 | int sctp_auth_set_key(struct sctp_endpoint *ep, | |
819 | struct sctp_association *asoc, | |
820 | struct sctp_authkey *auth_key) | |
821 | { | |
822 | struct sctp_shared_key *cur_key = NULL; | |
823 | struct sctp_auth_bytes *key; | |
824 | struct list_head *sh_keys; | |
825 | int replace = 0; | |
826 | ||
827 | /* Try to find the given key id to see if | |
828 | * we are doing a replace, or adding a new key | |
829 | */ | |
830 | if (asoc) | |
831 | sh_keys = &asoc->endpoint_shared_keys; | |
832 | else | |
833 | sh_keys = &ep->endpoint_shared_keys; | |
834 | ||
835 | key_for_each(cur_key, sh_keys) { | |
836 | if (cur_key->key_id == auth_key->sca_keynumber) { | |
837 | replace = 1; | |
838 | break; | |
839 | } | |
840 | } | |
841 | ||
842 | /* If we are not replacing a key id, we need to allocate | |
843 | * a shared key. | |
844 | */ | |
845 | if (!replace) { | |
846 | cur_key = sctp_auth_shkey_create(auth_key->sca_keynumber, | |
847 | GFP_KERNEL); | |
848 | if (!cur_key) | |
849 | return -ENOMEM; | |
850 | } | |
851 | ||
852 | /* Create a new key data based on the info passed in */ | |
7e8616d8 | 853 | key = sctp_auth_create_key(auth_key->sca_keylength, GFP_KERNEL); |
65b07e5d VY |
854 | if (!key) |
855 | goto nomem; | |
856 | ||
7e8616d8 | 857 | memcpy(key->data, &auth_key->sca_key[0], auth_key->sca_keylength); |
65b07e5d VY |
858 | |
859 | /* If we are replacing, remove the old keys data from the | |
860 | * key id. If we are adding new key id, add it to the | |
861 | * list. | |
862 | */ | |
863 | if (replace) | |
864 | sctp_auth_key_put(cur_key->key); | |
865 | else | |
866 | list_add(&cur_key->key_list, sh_keys); | |
867 | ||
868 | cur_key->key = key; | |
869 | sctp_auth_key_hold(key); | |
870 | ||
871 | return 0; | |
872 | nomem: | |
873 | if (!replace) | |
874 | sctp_auth_shkey_free(cur_key); | |
875 | ||
876 | return -ENOMEM; | |
877 | } | |
878 | ||
879 | int sctp_auth_set_active_key(struct sctp_endpoint *ep, | |
880 | struct sctp_association *asoc, | |
881 | __u16 key_id) | |
882 | { | |
883 | struct sctp_shared_key *key; | |
884 | struct list_head *sh_keys; | |
885 | int found = 0; | |
886 | ||
887 | /* The key identifier MUST correst to an existing key */ | |
888 | if (asoc) | |
889 | sh_keys = &asoc->endpoint_shared_keys; | |
890 | else | |
891 | sh_keys = &ep->endpoint_shared_keys; | |
892 | ||
893 | key_for_each(key, sh_keys) { | |
894 | if (key->key_id == key_id) { | |
895 | found = 1; | |
896 | break; | |
897 | } | |
898 | } | |
899 | ||
900 | if (!found) | |
901 | return -EINVAL; | |
902 | ||
903 | if (asoc) { | |
904 | asoc->active_key_id = key_id; | |
905 | sctp_auth_asoc_init_active_key(asoc, GFP_KERNEL); | |
906 | } else | |
907 | ep->active_key_id = key_id; | |
908 | ||
909 | return 0; | |
910 | } | |
911 | ||
912 | int sctp_auth_del_key_id(struct sctp_endpoint *ep, | |
913 | struct sctp_association *asoc, | |
914 | __u16 key_id) | |
915 | { | |
916 | struct sctp_shared_key *key; | |
917 | struct list_head *sh_keys; | |
918 | int found = 0; | |
919 | ||
920 | /* The key identifier MUST NOT be the current active key | |
921 | * The key identifier MUST correst to an existing key | |
922 | */ | |
923 | if (asoc) { | |
924 | if (asoc->active_key_id == key_id) | |
925 | return -EINVAL; | |
926 | ||
927 | sh_keys = &asoc->endpoint_shared_keys; | |
928 | } else { | |
929 | if (ep->active_key_id == key_id) | |
930 | return -EINVAL; | |
931 | ||
932 | sh_keys = &ep->endpoint_shared_keys; | |
933 | } | |
934 | ||
935 | key_for_each(key, sh_keys) { | |
936 | if (key->key_id == key_id) { | |
937 | found = 1; | |
938 | break; | |
939 | } | |
940 | } | |
941 | ||
942 | if (!found) | |
943 | return -EINVAL; | |
944 | ||
945 | /* Delete the shared key */ | |
946 | list_del_init(&key->key_list); | |
947 | sctp_auth_shkey_free(key); | |
948 | ||
949 | return 0; | |
950 | } |