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Vlad Yasevich60c778b2008-01-11 09:57:09 -05001/* SCTP kernel implementation
Vlad Yasevich1f485642007-10-09 01:15:59 -07002 * (C) Copyright 2007 Hewlett-Packard Development Company, L.P.
3 *
Vlad Yasevich60c778b2008-01-11 09:57:09 -05004 * This file is part of the SCTP kernel implementation
Vlad Yasevich1f485642007-10-09 01:15:59 -07005 *
Vlad Yasevich60c778b2008-01-11 09:57:09 -05006 * This SCTP implementation is free software;
Vlad Yasevich1f485642007-10-09 01:15:59 -07007 * 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 *
Vlad Yasevich60c778b2008-01-11 09:57:09 -050012 * This SCTP implementation is distributed in the hope that it
Vlad Yasevich1f485642007-10-09 01:15:59 -070013 * 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
43static struct sctp_hmac sctp_hmac_list[SCTP_AUTH_NUM_HMACS] = {
44 {
45 /* id 0 is reserved. as all 0 */
46 .hmac_id = SCTP_AUTH_HMAC_ID_RESERVED_0,
47 },
48 {
49 .hmac_id = SCTP_AUTH_HMAC_ID_SHA1,
50 .hmac_name="hmac(sha1)",
51 .hmac_len = SCTP_SHA1_SIG_SIZE,
52 },
53 {
54 /* id 2 is reserved as well */
55 .hmac_id = SCTP_AUTH_HMAC_ID_RESERVED_2,
56 },
Vlad Yasevichb7e0fe92007-11-29 09:53:52 -050057#if defined (CONFIG_CRYPTO_SHA256) || defined (CONFIG_CRYPTO_SHA256_MODULE)
Vlad Yasevich1f485642007-10-09 01:15:59 -070058 {
59 .hmac_id = SCTP_AUTH_HMAC_ID_SHA256,
60 .hmac_name="hmac(sha256)",
61 .hmac_len = SCTP_SHA256_SIG_SIZE,
62 }
Vlad Yasevichb7e0fe92007-11-29 09:53:52 -050063#endif
Vlad Yasevich1f485642007-10-09 01:15:59 -070064};
65
66
67void sctp_auth_key_put(struct sctp_auth_bytes *key)
68{
69 if (!key)
70 return;
71
72 if (atomic_dec_and_test(&key->refcnt)) {
73 kfree(key);
74 SCTP_DBG_OBJCNT_DEC(keys);
75 }
76}
77
78/* Create a new key structure of a given length */
79static struct sctp_auth_bytes *sctp_auth_create_key(__u32 key_len, gfp_t gfp)
80{
81 struct sctp_auth_bytes *key;
82
83 /* Allocate the shared key */
84 key = kmalloc(sizeof(struct sctp_auth_bytes) + key_len, gfp);
85 if (!key)
86 return NULL;
87
88 key->len = key_len;
89 atomic_set(&key->refcnt, 1);
90 SCTP_DBG_OBJCNT_INC(keys);
91
92 return key;
93}
94
95/* Create a new shared key container with a give key id */
96struct sctp_shared_key *sctp_auth_shkey_create(__u16 key_id, gfp_t gfp)
97{
98 struct sctp_shared_key *new;
99
100 /* Allocate the shared key container */
101 new = kzalloc(sizeof(struct sctp_shared_key), gfp);
102 if (!new)
103 return NULL;
104
105 INIT_LIST_HEAD(&new->key_list);
106 new->key_id = key_id;
107
108 return new;
109}
110
111/* Free the shared key stucture */
Adrian Bunk8ad7c62b2007-10-26 04:21:23 -0700112static void sctp_auth_shkey_free(struct sctp_shared_key *sh_key)
Vlad Yasevich1f485642007-10-09 01:15:59 -0700113{
114 BUG_ON(!list_empty(&sh_key->key_list));
115 sctp_auth_key_put(sh_key->key);
116 sh_key->key = NULL;
117 kfree(sh_key);
118}
119
120/* Destory the entire key list. This is done during the
121 * associon and endpoint free process.
122 */
123void sctp_auth_destroy_keys(struct list_head *keys)
124{
125 struct sctp_shared_key *ep_key;
126 struct sctp_shared_key *tmp;
127
128 if (list_empty(keys))
129 return;
130
131 key_for_each_safe(ep_key, tmp, keys) {
132 list_del_init(&ep_key->key_list);
133 sctp_auth_shkey_free(ep_key);
134 }
135}
136
137/* Compare two byte vectors as numbers. Return values
138 * are:
139 * 0 - vectors are equal
140 * < 0 - vector 1 is smaller then vector2
141 * > 0 - vector 1 is greater then vector2
142 *
143 * Algorithm is:
144 * This is performed by selecting the numerically smaller key vector...
145 * If the key vectors are equal as numbers but differ in length ...
146 * the shorter vector is considered smaller
147 *
148 * Examples (with small values):
149 * 000123456789 > 123456789 (first number is longer)
150 * 000123456789 < 234567891 (second number is larger numerically)
151 * 123456789 > 2345678 (first number is both larger & longer)
152 */
153static int sctp_auth_compare_vectors(struct sctp_auth_bytes *vector1,
154 struct sctp_auth_bytes *vector2)
155{
156 int diff;
157 int i;
158 const __u8 *longer;
159
160 diff = vector1->len - vector2->len;
161 if (diff) {
162 longer = (diff > 0) ? vector1->data : vector2->data;
163
164 /* Check to see if the longer number is
165 * lead-zero padded. If it is not, it
166 * is automatically larger numerically.
167 */
168 for (i = 0; i < abs(diff); i++ ) {
169 if (longer[i] != 0)
170 return diff;
171 }
172 }
173
174 /* lengths are the same, compare numbers */
175 return memcmp(vector1->data, vector2->data, vector1->len);
176}
177
178/*
179 * Create a key vector as described in SCTP-AUTH, Section 6.1
180 * The RANDOM parameter, the CHUNKS parameter and the HMAC-ALGO
181 * parameter sent by each endpoint are concatenated as byte vectors.
182 * These parameters include the parameter type, parameter length, and
183 * the parameter value, but padding is omitted; all padding MUST be
184 * removed from this concatenation before proceeding with further
185 * computation of keys. Parameters which were not sent are simply
186 * omitted from the concatenation process. The resulting two vectors
187 * are called the two key vectors.
188 */
189static struct sctp_auth_bytes *sctp_auth_make_key_vector(
190 sctp_random_param_t *random,
191 sctp_chunks_param_t *chunks,
192 sctp_hmac_algo_param_t *hmacs,
193 gfp_t gfp)
194{
195 struct sctp_auth_bytes *new;
196 __u32 len;
197 __u32 offset = 0;
198
199 len = ntohs(random->param_hdr.length) + ntohs(hmacs->param_hdr.length);
200 if (chunks)
201 len += ntohs(chunks->param_hdr.length);
202
203 new = kmalloc(sizeof(struct sctp_auth_bytes) + len, gfp);
204 if (!new)
205 return NULL;
206
207 new->len = len;
208
209 memcpy(new->data, random, ntohs(random->param_hdr.length));
210 offset += ntohs(random->param_hdr.length);
211
212 if (chunks) {
213 memcpy(new->data + offset, chunks,
214 ntohs(chunks->param_hdr.length));
215 offset += ntohs(chunks->param_hdr.length);
216 }
217
218 memcpy(new->data + offset, hmacs, ntohs(hmacs->param_hdr.length));
219
220 return new;
221}
222
223
224/* Make a key vector based on our local parameters */
Adrian Bunk8ad7c62b2007-10-26 04:21:23 -0700225static struct sctp_auth_bytes *sctp_auth_make_local_vector(
Vlad Yasevich1f485642007-10-09 01:15:59 -0700226 const struct sctp_association *asoc,
227 gfp_t gfp)
228{
229 return sctp_auth_make_key_vector(
230 (sctp_random_param_t*)asoc->c.auth_random,
231 (sctp_chunks_param_t*)asoc->c.auth_chunks,
232 (sctp_hmac_algo_param_t*)asoc->c.auth_hmacs,
233 gfp);
234}
235
236/* Make a key vector based on peer's parameters */
Adrian Bunk8ad7c62b2007-10-26 04:21:23 -0700237static struct sctp_auth_bytes *sctp_auth_make_peer_vector(
Vlad Yasevich1f485642007-10-09 01:15:59 -0700238 const struct sctp_association *asoc,
239 gfp_t gfp)
240{
241 return sctp_auth_make_key_vector(asoc->peer.peer_random,
242 asoc->peer.peer_chunks,
243 asoc->peer.peer_hmacs,
244 gfp);
245}
246
247
248/* Set the value of the association shared key base on the parameters
249 * given. The algorithm is:
250 * From the endpoint pair shared keys and the key vectors the
251 * association shared keys are computed. This is performed by selecting
252 * the numerically smaller key vector and concatenating it to the
253 * endpoint pair shared key, and then concatenating the numerically
254 * larger key vector to that. The result of the concatenation is the
255 * association shared key.
256 */
257static struct sctp_auth_bytes *sctp_auth_asoc_set_secret(
258 struct sctp_shared_key *ep_key,
259 struct sctp_auth_bytes *first_vector,
260 struct sctp_auth_bytes *last_vector,
261 gfp_t gfp)
262{
263 struct sctp_auth_bytes *secret;
264 __u32 offset = 0;
265 __u32 auth_len;
266
267 auth_len = first_vector->len + last_vector->len;
268 if (ep_key->key)
269 auth_len += ep_key->key->len;
270
271 secret = sctp_auth_create_key(auth_len, gfp);
272 if (!secret)
273 return NULL;
274
275 if (ep_key->key) {
276 memcpy(secret->data, ep_key->key->data, ep_key->key->len);
277 offset += ep_key->key->len;
278 }
279
280 memcpy(secret->data + offset, first_vector->data, first_vector->len);
281 offset += first_vector->len;
282
283 memcpy(secret->data + offset, last_vector->data, last_vector->len);
284
285 return secret;
286}
287
288/* Create an association shared key. Follow the algorithm
289 * described in SCTP-AUTH, Section 6.1
290 */
291static struct sctp_auth_bytes *sctp_auth_asoc_create_secret(
292 const struct sctp_association *asoc,
293 struct sctp_shared_key *ep_key,
294 gfp_t gfp)
295{
296 struct sctp_auth_bytes *local_key_vector;
297 struct sctp_auth_bytes *peer_key_vector;
298 struct sctp_auth_bytes *first_vector,
299 *last_vector;
300 struct sctp_auth_bytes *secret = NULL;
301 int cmp;
302
303
304 /* Now we need to build the key vectors
305 * SCTP-AUTH , Section 6.1
306 * The RANDOM parameter, the CHUNKS parameter and the HMAC-ALGO
307 * parameter sent by each endpoint are concatenated as byte vectors.
308 * These parameters include the parameter type, parameter length, and
309 * the parameter value, but padding is omitted; all padding MUST be
310 * removed from this concatenation before proceeding with further
311 * computation of keys. Parameters which were not sent are simply
312 * omitted from the concatenation process. The resulting two vectors
313 * are called the two key vectors.
314 */
315
316 local_key_vector = sctp_auth_make_local_vector(asoc, gfp);
317 peer_key_vector = sctp_auth_make_peer_vector(asoc, gfp);
318
319 if (!peer_key_vector || !local_key_vector)
320 goto out;
321
322 /* Figure out the order in wich the key_vectors will be
323 * added to the endpoint shared key.
324 * SCTP-AUTH, Section 6.1:
325 * This is performed by selecting the numerically smaller key
326 * vector and concatenating it to the endpoint pair shared
327 * key, and then concatenating the numerically larger key
328 * vector to that. If the key vectors are equal as numbers
329 * but differ in length, then the concatenation order is the
330 * endpoint shared key, followed by the shorter key vector,
331 * followed by the longer key vector. Otherwise, the key
332 * vectors are identical, and may be concatenated to the
333 * endpoint pair key in any order.
334 */
335 cmp = sctp_auth_compare_vectors(local_key_vector,
336 peer_key_vector);
337 if (cmp < 0) {
338 first_vector = local_key_vector;
339 last_vector = peer_key_vector;
340 } else {
341 first_vector = peer_key_vector;
342 last_vector = local_key_vector;
343 }
344
345 secret = sctp_auth_asoc_set_secret(ep_key, first_vector, last_vector,
346 gfp);
347out:
348 kfree(local_key_vector);
349 kfree(peer_key_vector);
350
351 return secret;
352}
353
354/*
355 * Populate the association overlay list with the list
356 * from the endpoint.
357 */
358int sctp_auth_asoc_copy_shkeys(const struct sctp_endpoint *ep,
359 struct sctp_association *asoc,
360 gfp_t gfp)
361{
362 struct sctp_shared_key *sh_key;
363 struct sctp_shared_key *new;
364
365 BUG_ON(!list_empty(&asoc->endpoint_shared_keys));
366
367 key_for_each(sh_key, &ep->endpoint_shared_keys) {
368 new = sctp_auth_shkey_create(sh_key->key_id, gfp);
369 if (!new)
370 goto nomem;
371
372 new->key = sh_key->key;
373 sctp_auth_key_hold(new->key);
374 list_add(&new->key_list, &asoc->endpoint_shared_keys);
375 }
376
377 return 0;
378
379nomem:
380 sctp_auth_destroy_keys(&asoc->endpoint_shared_keys);
381 return -ENOMEM;
382}
383
384
385/* Public interface to creat the association shared key.
386 * See code above for the algorithm.
387 */
388int sctp_auth_asoc_init_active_key(struct sctp_association *asoc, gfp_t gfp)
389{
390 struct sctp_auth_bytes *secret;
391 struct sctp_shared_key *ep_key;
392
393 /* If we don't support AUTH, or peer is not capable
394 * we don't need to do anything.
395 */
396 if (!sctp_auth_enable || !asoc->peer.auth_capable)
397 return 0;
398
399 /* If the key_id is non-zero and we couldn't find an
400 * endpoint pair shared key, we can't compute the
401 * secret.
402 * For key_id 0, endpoint pair shared key is a NULL key.
403 */
404 ep_key = sctp_auth_get_shkey(asoc, asoc->active_key_id);
405 BUG_ON(!ep_key);
406
407 secret = sctp_auth_asoc_create_secret(asoc, ep_key, gfp);
408 if (!secret)
409 return -ENOMEM;
410
411 sctp_auth_key_put(asoc->asoc_shared_key);
412 asoc->asoc_shared_key = secret;
413
414 return 0;
415}
416
417
418/* Find the endpoint pair shared key based on the key_id */
419struct sctp_shared_key *sctp_auth_get_shkey(
420 const struct sctp_association *asoc,
421 __u16 key_id)
422{
Wei Yongjun7cc08b52008-02-05 03:03:06 -0800423 struct sctp_shared_key *key;
Vlad Yasevich1f485642007-10-09 01:15:59 -0700424
425 /* First search associations set of endpoint pair shared keys */
426 key_for_each(key, &asoc->endpoint_shared_keys) {
427 if (key->key_id == key_id)
Wei Yongjun7cc08b52008-02-05 03:03:06 -0800428 return key;
Vlad Yasevich1f485642007-10-09 01:15:59 -0700429 }
430
Wei Yongjun7cc08b52008-02-05 03:03:06 -0800431 return NULL;
Vlad Yasevich1f485642007-10-09 01:15:59 -0700432}
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 */
441int sctp_auth_init_hmacs(struct sctp_endpoint *ep, gfp_t gfp)
442{
443 struct crypto_hash *tfm = NULL;
444 __u16 id;
445
446 /* if the transforms are already allocted, we are done */
447 if (!sctp_auth_enable) {
448 ep->auth_hmacs = NULL;
449 return 0;
450 }
451
452 if (ep->auth_hmacs)
453 return 0;
454
455 /* Allocated the array of pointers to transorms */
456 ep->auth_hmacs = kzalloc(
457 sizeof(struct crypto_hash *) * SCTP_AUTH_NUM_HMACS,
458 gfp);
459 if (!ep->auth_hmacs)
460 return -ENOMEM;
461
462 for (id = 0; id < SCTP_AUTH_NUM_HMACS; id++) {
463
464 /* See is we support the id. Supported IDs have name and
465 * length fields set, so that we can allocated and use
466 * them. We can safely just check for name, for without the
467 * name, we can't allocate the TFM.
468 */
469 if (!sctp_hmac_list[id].hmac_name)
470 continue;
471
472 /* If this TFM has been allocated, we are all set */
473 if (ep->auth_hmacs[id])
474 continue;
475
476 /* Allocate the ID */
477 tfm = crypto_alloc_hash(sctp_hmac_list[id].hmac_name, 0,
478 CRYPTO_ALG_ASYNC);
479 if (IS_ERR(tfm))
480 goto out_err;
481
482 ep->auth_hmacs[id] = tfm;
483 }
484
485 return 0;
486
487out_err:
488 /* Clean up any successfull allocations */
489 sctp_auth_destroy_hmacs(ep->auth_hmacs);
490 return -ENOMEM;
491}
492
493/* Destroy the hmac tfm array */
494void sctp_auth_destroy_hmacs(struct crypto_hash *auth_hmacs[])
495{
496 int i;
497
498 if (!auth_hmacs)
499 return;
500
501 for (i = 0; i < SCTP_AUTH_NUM_HMACS; i++)
502 {
503 if (auth_hmacs[i])
504 crypto_free_hash(auth_hmacs[i]);
505 }
506 kfree(auth_hmacs);
507}
508
509
510struct 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 */
518struct sctp_hmac *sctp_auth_asoc_get_hmac(const struct sctp_association *asoc)
519{
520 struct sctp_hmac_algo_param *hmacs;
521 __u16 n_elt;
522 __u16 id = 0;
523 int i;
524
525 /* If we have a default entry, use it */
526 if (asoc->default_hmac_id)
527 return &sctp_hmac_list[asoc->default_hmac_id];
528
529 /* Since we do not have a default entry, find the first entry
530 * we support and return that. Do not cache that id.
531 */
532 hmacs = asoc->peer.peer_hmacs;
533 if (!hmacs)
534 return NULL;
535
536 n_elt = (ntohs(hmacs->param_hdr.length) - sizeof(sctp_paramhdr_t)) >> 1;
537 for (i = 0; i < n_elt; i++) {
538 id = ntohs(hmacs->hmac_ids[i]);
539
540 /* Check the id is in the supported range */
541 if (id > SCTP_AUTH_HMAC_ID_MAX)
542 continue;
543
544 /* See is we support the id. Supported IDs have name and
545 * length fields set, so that we can allocated and use
546 * them. We can safely just check for name, for without the
547 * name, we can't allocate the TFM.
548 */
549 if (!sctp_hmac_list[id].hmac_name)
550 continue;
551
552 break;
553 }
554
555 if (id == 0)
556 return NULL;
557
558 return &sctp_hmac_list[id];
559}
560
Al Virod06f6082007-10-29 05:03:23 +0000561static int __sctp_auth_find_hmacid(__be16 *hmacs, int n_elts, __be16 hmac_id)
Vlad Yasevich1f485642007-10-09 01:15:59 -0700562{
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 */
577int sctp_auth_asoc_verify_hmac_id(const struct sctp_association *asoc,
Al Virod06f6082007-10-29 05:03:23 +0000578 __be16 hmac_id)
Vlad Yasevich1f485642007-10-09 01:15:59 -0700579{
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 */
598void 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 */
630static int __sctp_auth_cid(sctp_cid_t chunk, struct sctp_chunks_param *param)
631{
632 unsigned short len;
633 int found = 0;
634 int i;
635
Vlad Yasevich555d3d52007-11-29 08:56:16 -0500636 if (!param || param->param_hdr.length == 0)
Vlad Yasevich1f485642007-10-09 01:15:59 -0700637 return 0;
638
639 len = ntohs(param->param_hdr.length) - sizeof(sctp_paramhdr_t);
640
641 /* SCTP-AUTH, Section 3.2
642 * The chunk types for INIT, INIT-ACK, SHUTDOWN-COMPLETE and AUTH
643 * chunks MUST NOT be listed in the CHUNKS parameter. However, if
644 * a CHUNKS parameter is received then the types for INIT, INIT-ACK,
645 * SHUTDOWN-COMPLETE and AUTH chunks MUST be ignored.
646 */
647 for (i = 0; !found && i < len; i++) {
648 switch (param->chunks[i]) {
649 case SCTP_CID_INIT:
650 case SCTP_CID_INIT_ACK:
651 case SCTP_CID_SHUTDOWN_COMPLETE:
652 case SCTP_CID_AUTH:
653 break;
654
655 default:
656 if (param->chunks[i] == chunk)
657 found = 1;
658 break;
659 }
660 }
661
662 return found;
663}
664
665/* Check if peer requested that this chunk is authenticated */
666int sctp_auth_send_cid(sctp_cid_t chunk, const struct sctp_association *asoc)
667{
668 if (!sctp_auth_enable || !asoc || !asoc->peer.auth_capable)
669 return 0;
670
671 return __sctp_auth_cid(chunk, asoc->peer.peer_chunks);
672}
673
674/* Check if we requested that peer authenticate this chunk. */
675int sctp_auth_recv_cid(sctp_cid_t chunk, const struct sctp_association *asoc)
676{
677 if (!sctp_auth_enable || !asoc)
678 return 0;
679
680 return __sctp_auth_cid(chunk,
681 (struct sctp_chunks_param *)asoc->c.auth_chunks);
682}
683
684/* SCTP-AUTH: Section 6.2:
685 * The sender MUST calculate the MAC as described in RFC2104 [2] using
686 * the hash function H as described by the MAC Identifier and the shared
687 * association key K based on the endpoint pair shared key described by
688 * the shared key identifier. The 'data' used for the computation of
689 * the AUTH-chunk is given by the AUTH chunk with its HMAC field set to
690 * zero (as shown in Figure 6) followed by all chunks that are placed
691 * after the AUTH chunk in the SCTP packet.
692 */
693void sctp_auth_calculate_hmac(const struct sctp_association *asoc,
694 struct sk_buff *skb,
695 struct sctp_auth_chunk *auth,
696 gfp_t gfp)
697{
698 struct scatterlist sg;
699 struct hash_desc desc;
700 struct sctp_auth_bytes *asoc_key;
701 __u16 key_id, hmac_id;
702 __u8 *digest;
703 unsigned char *end;
704 int free_key = 0;
705
706 /* Extract the info we need:
707 * - hmac id
708 * - key id
709 */
710 key_id = ntohs(auth->auth_hdr.shkey_id);
711 hmac_id = ntohs(auth->auth_hdr.hmac_id);
712
713 if (key_id == asoc->active_key_id)
714 asoc_key = asoc->asoc_shared_key;
715 else {
716 struct sctp_shared_key *ep_key;
717
718 ep_key = sctp_auth_get_shkey(asoc, key_id);
719 if (!ep_key)
720 return;
721
722 asoc_key = sctp_auth_asoc_create_secret(asoc, ep_key, gfp);
723 if (!asoc_key)
724 return;
725
726 free_key = 1;
727 }
728
729 /* set up scatter list */
730 end = skb_tail_pointer(skb);
Herbert Xu68e3f5d2007-10-27 00:52:07 -0700731 sg_init_one(&sg, auth, end - (unsigned char *)auth);
Vlad Yasevich1f485642007-10-09 01:15:59 -0700732
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
742free:
743 if (free_key)
744 sctp_auth_key_put(asoc_key);
745}
Vlad Yasevich65b07e52007-09-16 19:34:00 -0700746
747/* API Helpers */
748
749/* Add a chunk to the endpoint authenticated chunk list */
750int 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 */
772int 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 */
806int 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 */
Vlad Yasevich7e8616d2008-02-27 16:04:52 -0500841 key = sctp_auth_create_key(auth_key->sca_keylength, GFP_KERNEL);
Vlad Yasevich65b07e52007-09-16 19:34:00 -0700842 if (!key)
843 goto nomem;
844
Vlad Yasevich7e8616d2008-02-27 16:04:52 -0500845 memcpy(key->data, &auth_key->sca_key[0], auth_key->sca_keylength);
Vlad Yasevich65b07e52007-09-16 19:34:00 -0700846
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;
860nomem:
861 if (!replace)
862 sctp_auth_shkey_free(cur_key);
863
864 return -ENOMEM;
865}
866
867int 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
900int 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}