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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 | }, | |
57 | { | |
58 | .hmac_id = SCTP_AUTH_HMAC_ID_SHA256, | |
59 | .hmac_name="hmac(sha256)", | |
60 | .hmac_len = SCTP_SHA256_SIG_SIZE, | |
61 | } | |
62 | }; | |
63 | ||
64 | ||
65 | void sctp_auth_key_put(struct sctp_auth_bytes *key) | |
66 | { | |
67 | if (!key) | |
68 | return; | |
69 | ||
70 | if (atomic_dec_and_test(&key->refcnt)) { | |
71 | kfree(key); | |
72 | SCTP_DBG_OBJCNT_DEC(keys); | |
73 | } | |
74 | } | |
75 | ||
76 | /* Create a new key structure of a given length */ | |
77 | static struct sctp_auth_bytes *sctp_auth_create_key(__u32 key_len, gfp_t gfp) | |
78 | { | |
79 | struct sctp_auth_bytes *key; | |
80 | ||
81 | /* Allocate the shared key */ | |
82 | key = kmalloc(sizeof(struct sctp_auth_bytes) + key_len, gfp); | |
83 | if (!key) | |
84 | return NULL; | |
85 | ||
86 | key->len = key_len; | |
87 | atomic_set(&key->refcnt, 1); | |
88 | SCTP_DBG_OBJCNT_INC(keys); | |
89 | ||
90 | return key; | |
91 | } | |
92 | ||
93 | /* Create a new shared key container with a give key id */ | |
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 | ||
109 | /* Free the shared key stucture */ | |
110 | void sctp_auth_shkey_free(struct sctp_shared_key *sh_key) | |
111 | { | |
112 | BUG_ON(!list_empty(&sh_key->key_list)); | |
113 | sctp_auth_key_put(sh_key->key); | |
114 | sh_key->key = NULL; | |
115 | kfree(sh_key); | |
116 | } | |
117 | ||
118 | /* Destory the entire key list. This is done during the | |
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 | |
138 | * < 0 - vector 1 is smaller then vector2 | |
139 | * > 0 - vector 1 is greater then vector2 | |
140 | * | |
141 | * Algorithm is: | |
142 | * This is performed by selecting the numerically smaller key vector... | |
143 | * If the key vectors are equal as numbers but differ in length ... | |
144 | * the shorter vector is considered smaller | |
145 | * | |
146 | * Examples (with small values): | |
147 | * 000123456789 > 123456789 (first number is longer) | |
148 | * 000123456789 < 234567891 (second number is larger numerically) | |
149 | * 123456789 > 2345678 (first number is both larger & longer) | |
150 | */ | |
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 | */ | |
166 | for (i = 0; i < abs(diff); i++ ) { | |
167 | if (longer[i] != 0) | |
168 | return diff; | |
169 | } | |
170 | } | |
171 | ||
172 | /* lengths are the same, compare numbers */ | |
173 | return memcmp(vector1->data, vector2->data, vector1->len); | |
174 | } | |
175 | ||
176 | /* | |
177 | * Create a key vector as described in SCTP-AUTH, Section 6.1 | |
178 | * The RANDOM parameter, the CHUNKS parameter and the HMAC-ALGO | |
179 | * parameter sent by each endpoint are concatenated as byte vectors. | |
180 | * These parameters include the parameter type, parameter length, and | |
181 | * the parameter value, but padding is omitted; all padding MUST be | |
182 | * removed from this concatenation before proceeding with further | |
183 | * computation of keys. Parameters which were not sent are simply | |
184 | * omitted from the concatenation process. The resulting two vectors | |
185 | * are called the two key vectors. | |
186 | */ | |
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; | |
196 | ||
197 | len = ntohs(random->param_hdr.length) + ntohs(hmacs->param_hdr.length); | |
198 | if (chunks) | |
199 | len += ntohs(chunks->param_hdr.length); | |
200 | ||
201 | new = kmalloc(sizeof(struct sctp_auth_bytes) + len, gfp); | |
202 | if (!new) | |
203 | return NULL; | |
204 | ||
205 | new->len = len; | |
206 | ||
207 | memcpy(new->data, random, ntohs(random->param_hdr.length)); | |
208 | offset += ntohs(random->param_hdr.length); | |
209 | ||
210 | if (chunks) { | |
211 | memcpy(new->data + offset, chunks, | |
212 | ntohs(chunks->param_hdr.length)); | |
213 | offset += ntohs(chunks->param_hdr.length); | |
214 | } | |
215 | ||
216 | memcpy(new->data + offset, hmacs, ntohs(hmacs->param_hdr.length)); | |
217 | ||
218 | return new; | |
219 | } | |
220 | ||
221 | ||
222 | /* Make a key vector based on our local parameters */ | |
223 | struct sctp_auth_bytes *sctp_auth_make_local_vector( | |
224 | const struct sctp_association *asoc, | |
225 | gfp_t gfp) | |
226 | { | |
227 | return sctp_auth_make_key_vector( | |
228 | (sctp_random_param_t*)asoc->c.auth_random, | |
229 | (sctp_chunks_param_t*)asoc->c.auth_chunks, | |
230 | (sctp_hmac_algo_param_t*)asoc->c.auth_hmacs, | |
231 | gfp); | |
232 | } | |
233 | ||
234 | /* Make a key vector based on peer's parameters */ | |
235 | struct sctp_auth_bytes *sctp_auth_make_peer_vector( | |
236 | const struct sctp_association *asoc, | |
237 | gfp_t gfp) | |
238 | { | |
239 | return sctp_auth_make_key_vector(asoc->peer.peer_random, | |
240 | asoc->peer.peer_chunks, | |
241 | asoc->peer.peer_hmacs, | |
242 | gfp); | |
243 | } | |
244 | ||
245 | ||
246 | /* Set the value of the association shared key base on the parameters | |
247 | * given. The algorithm is: | |
248 | * From the endpoint pair shared keys and the key vectors the | |
249 | * association shared keys are computed. This is performed by selecting | |
250 | * the numerically smaller key vector and concatenating it to the | |
251 | * endpoint pair shared key, and then concatenating the numerically | |
252 | * larger key vector to that. The result of the concatenation is the | |
253 | * association shared key. | |
254 | */ | |
255 | static struct sctp_auth_bytes *sctp_auth_asoc_set_secret( | |
256 | struct sctp_shared_key *ep_key, | |
257 | struct sctp_auth_bytes *first_vector, | |
258 | struct sctp_auth_bytes *last_vector, | |
259 | gfp_t gfp) | |
260 | { | |
261 | struct sctp_auth_bytes *secret; | |
262 | __u32 offset = 0; | |
263 | __u32 auth_len; | |
264 | ||
265 | auth_len = first_vector->len + last_vector->len; | |
266 | if (ep_key->key) | |
267 | auth_len += ep_key->key->len; | |
268 | ||
269 | secret = sctp_auth_create_key(auth_len, gfp); | |
270 | if (!secret) | |
271 | return NULL; | |
272 | ||
273 | if (ep_key->key) { | |
274 | memcpy(secret->data, ep_key->key->data, ep_key->key->len); | |
275 | offset += ep_key->key->len; | |
276 | } | |
277 | ||
278 | memcpy(secret->data + offset, first_vector->data, first_vector->len); | |
279 | offset += first_vector->len; | |
280 | ||
281 | memcpy(secret->data + offset, last_vector->data, last_vector->len); | |
282 | ||
283 | return secret; | |
284 | } | |
285 | ||
286 | /* Create an association shared key. Follow the algorithm | |
287 | * described in SCTP-AUTH, Section 6.1 | |
288 | */ | |
289 | static struct sctp_auth_bytes *sctp_auth_asoc_create_secret( | |
290 | const struct sctp_association *asoc, | |
291 | struct sctp_shared_key *ep_key, | |
292 | gfp_t gfp) | |
293 | { | |
294 | struct sctp_auth_bytes *local_key_vector; | |
295 | struct sctp_auth_bytes *peer_key_vector; | |
296 | struct sctp_auth_bytes *first_vector, | |
297 | *last_vector; | |
298 | struct sctp_auth_bytes *secret = NULL; | |
299 | int cmp; | |
300 | ||
301 | ||
302 | /* Now we need to build the key vectors | |
303 | * SCTP-AUTH , Section 6.1 | |
304 | * The RANDOM parameter, the CHUNKS parameter and the HMAC-ALGO | |
305 | * parameter sent by each endpoint are concatenated as byte vectors. | |
306 | * These parameters include the parameter type, parameter length, and | |
307 | * the parameter value, but padding is omitted; all padding MUST be | |
308 | * removed from this concatenation before proceeding with further | |
309 | * computation of keys. Parameters which were not sent are simply | |
310 | * omitted from the concatenation process. The resulting two vectors | |
311 | * are called the two key vectors. | |
312 | */ | |
313 | ||
314 | local_key_vector = sctp_auth_make_local_vector(asoc, gfp); | |
315 | peer_key_vector = sctp_auth_make_peer_vector(asoc, gfp); | |
316 | ||
317 | if (!peer_key_vector || !local_key_vector) | |
318 | goto out; | |
319 | ||
320 | /* Figure out the order in wich the key_vectors will be | |
321 | * added to the endpoint shared key. | |
322 | * SCTP-AUTH, Section 6.1: | |
323 | * This is performed by selecting the numerically smaller key | |
324 | * vector and concatenating it to the endpoint pair shared | |
325 | * key, and then concatenating the numerically larger key | |
326 | * vector to that. If the key vectors are equal as numbers | |
327 | * but differ in length, then the concatenation order is the | |
328 | * endpoint shared key, followed by the shorter key vector, | |
329 | * followed by the longer key vector. Otherwise, the key | |
330 | * vectors are identical, and may be concatenated to the | |
331 | * endpoint pair key in any order. | |
332 | */ | |
333 | cmp = sctp_auth_compare_vectors(local_key_vector, | |
334 | peer_key_vector); | |
335 | if (cmp < 0) { | |
336 | first_vector = local_key_vector; | |
337 | last_vector = peer_key_vector; | |
338 | } else { | |
339 | first_vector = peer_key_vector; | |
340 | last_vector = local_key_vector; | |
341 | } | |
342 | ||
343 | secret = sctp_auth_asoc_set_secret(ep_key, first_vector, last_vector, | |
344 | gfp); | |
345 | out: | |
346 | kfree(local_key_vector); | |
347 | kfree(peer_key_vector); | |
348 | ||
349 | return secret; | |
350 | } | |
351 | ||
352 | /* | |
353 | * Populate the association overlay list with the list | |
354 | * from the endpoint. | |
355 | */ | |
356 | int sctp_auth_asoc_copy_shkeys(const struct sctp_endpoint *ep, | |
357 | struct sctp_association *asoc, | |
358 | gfp_t gfp) | |
359 | { | |
360 | struct sctp_shared_key *sh_key; | |
361 | struct sctp_shared_key *new; | |
362 | ||
363 | BUG_ON(!list_empty(&asoc->endpoint_shared_keys)); | |
364 | ||
365 | key_for_each(sh_key, &ep->endpoint_shared_keys) { | |
366 | new = sctp_auth_shkey_create(sh_key->key_id, gfp); | |
367 | if (!new) | |
368 | goto nomem; | |
369 | ||
370 | new->key = sh_key->key; | |
371 | sctp_auth_key_hold(new->key); | |
372 | list_add(&new->key_list, &asoc->endpoint_shared_keys); | |
373 | } | |
374 | ||
375 | return 0; | |
376 | ||
377 | nomem: | |
378 | sctp_auth_destroy_keys(&asoc->endpoint_shared_keys); | |
379 | return -ENOMEM; | |
380 | } | |
381 | ||
382 | ||
383 | /* Public interface to creat the association shared key. | |
384 | * See code above for the algorithm. | |
385 | */ | |
386 | int sctp_auth_asoc_init_active_key(struct sctp_association *asoc, gfp_t gfp) | |
387 | { | |
388 | struct sctp_auth_bytes *secret; | |
389 | struct sctp_shared_key *ep_key; | |
390 | ||
391 | /* If we don't support AUTH, or peer is not capable | |
392 | * we don't need to do anything. | |
393 | */ | |
394 | if (!sctp_auth_enable || !asoc->peer.auth_capable) | |
395 | return 0; | |
396 | ||
397 | /* If the key_id is non-zero and we couldn't find an | |
398 | * endpoint pair shared key, we can't compute the | |
399 | * secret. | |
400 | * For key_id 0, endpoint pair shared key is a NULL key. | |
401 | */ | |
402 | ep_key = sctp_auth_get_shkey(asoc, asoc->active_key_id); | |
403 | BUG_ON(!ep_key); | |
404 | ||
405 | secret = sctp_auth_asoc_create_secret(asoc, ep_key, gfp); | |
406 | if (!secret) | |
407 | return -ENOMEM; | |
408 | ||
409 | sctp_auth_key_put(asoc->asoc_shared_key); | |
410 | asoc->asoc_shared_key = secret; | |
411 | ||
412 | return 0; | |
413 | } | |
414 | ||
415 | ||
416 | /* Find the endpoint pair shared key based on the key_id */ | |
417 | struct sctp_shared_key *sctp_auth_get_shkey( | |
418 | const struct sctp_association *asoc, | |
419 | __u16 key_id) | |
420 | { | |
421 | struct sctp_shared_key *key = NULL; | |
422 | ||
423 | /* First search associations set of endpoint pair shared keys */ | |
424 | key_for_each(key, &asoc->endpoint_shared_keys) { | |
425 | if (key->key_id == key_id) | |
426 | break; | |
427 | } | |
428 | ||
429 | return key; | |
430 | } | |
431 | ||
432 | /* | |
433 | * Initialize all the possible digest transforms that we can use. Right now | |
434 | * now, the supported digests are SHA1 and SHA256. We do this here once | |
435 | * because of the restrictiong that transforms may only be allocated in | |
436 | * user context. This forces us to pre-allocated all possible transforms | |
437 | * at the endpoint init time. | |
438 | */ | |
439 | int sctp_auth_init_hmacs(struct sctp_endpoint *ep, gfp_t gfp) | |
440 | { | |
441 | struct crypto_hash *tfm = NULL; | |
442 | __u16 id; | |
443 | ||
444 | /* if the transforms are already allocted, we are done */ | |
445 | if (!sctp_auth_enable) { | |
446 | ep->auth_hmacs = NULL; | |
447 | return 0; | |
448 | } | |
449 | ||
450 | if (ep->auth_hmacs) | |
451 | return 0; | |
452 | ||
453 | /* Allocated the array of pointers to transorms */ | |
454 | ep->auth_hmacs = kzalloc( | |
455 | sizeof(struct crypto_hash *) * SCTP_AUTH_NUM_HMACS, | |
456 | gfp); | |
457 | if (!ep->auth_hmacs) | |
458 | return -ENOMEM; | |
459 | ||
460 | for (id = 0; id < SCTP_AUTH_NUM_HMACS; id++) { | |
461 | ||
462 | /* See is we support the id. Supported IDs have name and | |
463 | * length fields set, so that we can allocated and use | |
464 | * them. We can safely just check for name, for without the | |
465 | * name, we can't allocate the TFM. | |
466 | */ | |
467 | if (!sctp_hmac_list[id].hmac_name) | |
468 | continue; | |
469 | ||
470 | /* If this TFM has been allocated, we are all set */ | |
471 | if (ep->auth_hmacs[id]) | |
472 | continue; | |
473 | ||
474 | /* Allocate the ID */ | |
475 | tfm = crypto_alloc_hash(sctp_hmac_list[id].hmac_name, 0, | |
476 | CRYPTO_ALG_ASYNC); | |
477 | if (IS_ERR(tfm)) | |
478 | goto out_err; | |
479 | ||
480 | ep->auth_hmacs[id] = tfm; | |
481 | } | |
482 | ||
483 | return 0; | |
484 | ||
485 | out_err: | |
486 | /* Clean up any successfull allocations */ | |
487 | sctp_auth_destroy_hmacs(ep->auth_hmacs); | |
488 | return -ENOMEM; | |
489 | } | |
490 | ||
491 | /* Destroy the hmac tfm array */ | |
492 | void sctp_auth_destroy_hmacs(struct crypto_hash *auth_hmacs[]) | |
493 | { | |
494 | int i; | |
495 | ||
496 | if (!auth_hmacs) | |
497 | return; | |
498 | ||
499 | for (i = 0; i < SCTP_AUTH_NUM_HMACS; i++) | |
500 | { | |
501 | if (auth_hmacs[i]) | |
502 | crypto_free_hash(auth_hmacs[i]); | |
503 | } | |
504 | kfree(auth_hmacs); | |
505 | } | |
506 | ||
507 | ||
508 | struct sctp_hmac *sctp_auth_get_hmac(__u16 hmac_id) | |
509 | { | |
510 | return &sctp_hmac_list[hmac_id]; | |
511 | } | |
512 | ||
513 | /* Get an hmac description information that we can use to build | |
514 | * the AUTH chunk | |
515 | */ | |
516 | struct sctp_hmac *sctp_auth_asoc_get_hmac(const struct sctp_association *asoc) | |
517 | { | |
518 | struct sctp_hmac_algo_param *hmacs; | |
519 | __u16 n_elt; | |
520 | __u16 id = 0; | |
521 | int i; | |
522 | ||
523 | /* If we have a default entry, use it */ | |
524 | if (asoc->default_hmac_id) | |
525 | return &sctp_hmac_list[asoc->default_hmac_id]; | |
526 | ||
527 | /* Since we do not have a default entry, find the first entry | |
528 | * we support and return that. Do not cache that id. | |
529 | */ | |
530 | hmacs = asoc->peer.peer_hmacs; | |
531 | if (!hmacs) | |
532 | return NULL; | |
533 | ||
534 | n_elt = (ntohs(hmacs->param_hdr.length) - sizeof(sctp_paramhdr_t)) >> 1; | |
535 | for (i = 0; i < n_elt; i++) { | |
536 | id = ntohs(hmacs->hmac_ids[i]); | |
537 | ||
538 | /* Check the id is in the supported range */ | |
539 | if (id > SCTP_AUTH_HMAC_ID_MAX) | |
540 | continue; | |
541 | ||
542 | /* See is we support the id. Supported IDs have name and | |
543 | * length fields set, so that we can allocated and use | |
544 | * them. We can safely just check for name, for without the | |
545 | * name, we can't allocate the TFM. | |
546 | */ | |
547 | if (!sctp_hmac_list[id].hmac_name) | |
548 | continue; | |
549 | ||
550 | break; | |
551 | } | |
552 | ||
553 | if (id == 0) | |
554 | return NULL; | |
555 | ||
556 | return &sctp_hmac_list[id]; | |
557 | } | |
558 | ||
559 | static int __sctp_auth_find_hmacid(__u16 *hmacs, int n_elts, __u16 hmac_id) | |
560 | { | |
561 | int found = 0; | |
562 | int i; | |
563 | ||
564 | for (i = 0; i < n_elts; i++) { | |
565 | if (hmac_id == hmacs[i]) { | |
566 | found = 1; | |
567 | break; | |
568 | } | |
569 | } | |
570 | ||
571 | return found; | |
572 | } | |
573 | ||
574 | /* See if the HMAC_ID is one that we claim as supported */ | |
575 | int sctp_auth_asoc_verify_hmac_id(const struct sctp_association *asoc, | |
576 | __u16 hmac_id) | |
577 | { | |
578 | struct sctp_hmac_algo_param *hmacs; | |
579 | __u16 n_elt; | |
580 | ||
581 | if (!asoc) | |
582 | return 0; | |
583 | ||
584 | hmacs = (struct sctp_hmac_algo_param *)asoc->c.auth_hmacs; | |
585 | n_elt = (ntohs(hmacs->param_hdr.length) - sizeof(sctp_paramhdr_t)) >> 1; | |
586 | ||
587 | return __sctp_auth_find_hmacid(hmacs->hmac_ids, n_elt, hmac_id); | |
588 | } | |
589 | ||
590 | ||
591 | /* Cache the default HMAC id. This to follow this text from SCTP-AUTH: | |
592 | * Section 6.1: | |
593 | * The receiver of a HMAC-ALGO parameter SHOULD use the first listed | |
594 | * algorithm it supports. | |
595 | */ | |
596 | void sctp_auth_asoc_set_default_hmac(struct sctp_association *asoc, | |
597 | struct sctp_hmac_algo_param *hmacs) | |
598 | { | |
599 | struct sctp_endpoint *ep; | |
600 | __u16 id; | |
601 | int i; | |
602 | int n_params; | |
603 | ||
604 | /* if the default id is already set, use it */ | |
605 | if (asoc->default_hmac_id) | |
606 | return; | |
607 | ||
608 | n_params = (ntohs(hmacs->param_hdr.length) | |
609 | - sizeof(sctp_paramhdr_t)) >> 1; | |
610 | ep = asoc->ep; | |
611 | for (i = 0; i < n_params; i++) { | |
612 | id = ntohs(hmacs->hmac_ids[i]); | |
613 | ||
614 | /* Check the id is in the supported range */ | |
615 | if (id > SCTP_AUTH_HMAC_ID_MAX) | |
616 | continue; | |
617 | ||
618 | /* If this TFM has been allocated, use this id */ | |
619 | if (ep->auth_hmacs[id]) { | |
620 | asoc->default_hmac_id = id; | |
621 | break; | |
622 | } | |
623 | } | |
624 | } | |
625 | ||
626 | ||
627 | /* Check to see if the given chunk is supposed to be authenticated */ | |
628 | static int __sctp_auth_cid(sctp_cid_t chunk, struct sctp_chunks_param *param) | |
629 | { | |
630 | unsigned short len; | |
631 | int found = 0; | |
632 | int i; | |
633 | ||
634 | if (!param) | |
635 | return 0; | |
636 | ||
637 | len = ntohs(param->param_hdr.length) - sizeof(sctp_paramhdr_t); | |
638 | ||
639 | /* SCTP-AUTH, Section 3.2 | |
640 | * The chunk types for INIT, INIT-ACK, SHUTDOWN-COMPLETE and AUTH | |
641 | * chunks MUST NOT be listed in the CHUNKS parameter. However, if | |
642 | * a CHUNKS parameter is received then the types for INIT, INIT-ACK, | |
643 | * SHUTDOWN-COMPLETE and AUTH chunks MUST be ignored. | |
644 | */ | |
645 | for (i = 0; !found && i < len; i++) { | |
646 | switch (param->chunks[i]) { | |
647 | case SCTP_CID_INIT: | |
648 | case SCTP_CID_INIT_ACK: | |
649 | case SCTP_CID_SHUTDOWN_COMPLETE: | |
650 | case SCTP_CID_AUTH: | |
651 | break; | |
652 | ||
653 | default: | |
654 | if (param->chunks[i] == chunk) | |
655 | found = 1; | |
656 | break; | |
657 | } | |
658 | } | |
659 | ||
660 | return found; | |
661 | } | |
662 | ||
663 | /* Check if peer requested that this chunk is authenticated */ | |
664 | int sctp_auth_send_cid(sctp_cid_t chunk, const struct sctp_association *asoc) | |
665 | { | |
666 | if (!sctp_auth_enable || !asoc || !asoc->peer.auth_capable) | |
667 | return 0; | |
668 | ||
669 | return __sctp_auth_cid(chunk, asoc->peer.peer_chunks); | |
670 | } | |
671 | ||
672 | /* Check if we requested that peer authenticate this chunk. */ | |
673 | int sctp_auth_recv_cid(sctp_cid_t chunk, const struct sctp_association *asoc) | |
674 | { | |
675 | if (!sctp_auth_enable || !asoc) | |
676 | return 0; | |
677 | ||
678 | return __sctp_auth_cid(chunk, | |
679 | (struct sctp_chunks_param *)asoc->c.auth_chunks); | |
680 | } | |
681 | ||
682 | /* SCTP-AUTH: Section 6.2: | |
683 | * The sender MUST calculate the MAC as described in RFC2104 [2] using | |
684 | * the hash function H as described by the MAC Identifier and the shared | |
685 | * association key K based on the endpoint pair shared key described by | |
686 | * the shared key identifier. The 'data' used for the computation of | |
687 | * the AUTH-chunk is given by the AUTH chunk with its HMAC field set to | |
688 | * zero (as shown in Figure 6) followed by all chunks that are placed | |
689 | * after the AUTH chunk in the SCTP packet. | |
690 | */ | |
691 | void sctp_auth_calculate_hmac(const struct sctp_association *asoc, | |
692 | struct sk_buff *skb, | |
693 | struct sctp_auth_chunk *auth, | |
694 | gfp_t gfp) | |
695 | { | |
696 | struct scatterlist sg; | |
697 | struct hash_desc desc; | |
698 | struct sctp_auth_bytes *asoc_key; | |
699 | __u16 key_id, hmac_id; | |
700 | __u8 *digest; | |
701 | unsigned char *end; | |
702 | int free_key = 0; | |
703 | ||
704 | /* Extract the info we need: | |
705 | * - hmac id | |
706 | * - key id | |
707 | */ | |
708 | key_id = ntohs(auth->auth_hdr.shkey_id); | |
709 | hmac_id = ntohs(auth->auth_hdr.hmac_id); | |
710 | ||
711 | if (key_id == asoc->active_key_id) | |
712 | asoc_key = asoc->asoc_shared_key; | |
713 | else { | |
714 | struct sctp_shared_key *ep_key; | |
715 | ||
716 | ep_key = sctp_auth_get_shkey(asoc, key_id); | |
717 | if (!ep_key) | |
718 | return; | |
719 | ||
720 | asoc_key = sctp_auth_asoc_create_secret(asoc, ep_key, gfp); | |
721 | if (!asoc_key) | |
722 | return; | |
723 | ||
724 | free_key = 1; | |
725 | } | |
726 | ||
727 | /* set up scatter list */ | |
728 | end = skb_tail_pointer(skb); | |
729 | sg.page = virt_to_page(auth); | |
730 | sg.offset = (unsigned long)(auth) % PAGE_SIZE; | |
731 | sg.length = end - (unsigned char *)auth; | |
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 | } | |
65b07e5d VY |
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 | } |