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1/* SCTP kernel implementation
2 * (C) Copyright 2007 Hewlett-Packard Development Company, L.P.
3 *
4 * This file is part of the SCTP kernel implementation
5 *
6 * This SCTP 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 * This SCTP 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, see
20 * <http://www.gnu.org/licenses/>.
21 *
22 * Please send any bug reports or fixes you make to the
23 * email address(es):
24 * lksctp developers <linux-sctp@vger.kernel.org>
25 *
26 * Written or modified by:
27 * Vlad Yasevich <vladislav.yasevich@hp.com>
28 */
29
30#include <linux/slab.h>
31#include <linux/types.h>
32#include <linux/crypto.h>
33#include <linux/scatterlist.h>
34#include <net/sctp/sctp.h>
35#include <net/sctp/auth.h>
36
37static struct sctp_hmac sctp_hmac_list[SCTP_AUTH_NUM_HMACS] = {
38 {
39 /* id 0 is reserved. as all 0 */
40 .hmac_id = SCTP_AUTH_HMAC_ID_RESERVED_0,
41 },
42 {
43 .hmac_id = SCTP_AUTH_HMAC_ID_SHA1,
44 .hmac_name = "hmac(sha1)",
45 .hmac_len = SCTP_SHA1_SIG_SIZE,
46 },
47 {
48 /* id 2 is reserved as well */
49 .hmac_id = SCTP_AUTH_HMAC_ID_RESERVED_2,
50 },
51#if defined (CONFIG_CRYPTO_SHA256) || defined (CONFIG_CRYPTO_SHA256_MODULE)
52 {
53 .hmac_id = SCTP_AUTH_HMAC_ID_SHA256,
54 .hmac_name = "hmac(sha256)",
55 .hmac_len = SCTP_SHA256_SIG_SIZE,
56 }
57#endif
58};
59
60
61void sctp_auth_key_put(struct sctp_auth_bytes *key)
62{
63 if (!key)
64 return;
65
66 if (atomic_dec_and_test(&key->refcnt)) {
67 kzfree(key);
68 SCTP_DBG_OBJCNT_DEC(keys);
69 }
70}
71
72/* Create a new key structure of a given length */
73static struct sctp_auth_bytes *sctp_auth_create_key(__u32 key_len, gfp_t gfp)
74{
75 struct sctp_auth_bytes *key;
76
77 /* Verify that we are not going to overflow INT_MAX */
78 if (key_len > (INT_MAX - sizeof(struct sctp_auth_bytes)))
79 return NULL;
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 */
94struct 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 structure */
110static 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/* Destroy the entire key list. This is done during the
119 * associon and endpoint free process.
120 */
121void 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 than vector2
139 * > 0 - vector 1 is greater than 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 */
151static 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 */
187static 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 __u16 random_len, hmacs_len, chunks_len = 0;
197
198 random_len = ntohs(random->param_hdr.length);
199 hmacs_len = ntohs(hmacs->param_hdr.length);
200 if (chunks)
201 chunks_len = ntohs(chunks->param_hdr.length);
202
203 len = random_len + hmacs_len + chunks_len;
204
205 new = sctp_auth_create_key(len, gfp);
206 if (!new)
207 return NULL;
208
209 memcpy(new->data, random, random_len);
210 offset += random_len;
211
212 if (chunks) {
213 memcpy(new->data + offset, chunks, chunks_len);
214 offset += chunks_len;
215 }
216
217 memcpy(new->data + offset, hmacs, hmacs_len);
218
219 return new;
220}
221
222
223/* Make a key vector based on our local parameters */
224static struct sctp_auth_bytes *sctp_auth_make_local_vector(
225 const struct sctp_association *asoc,
226 gfp_t gfp)
227{
228 return sctp_auth_make_key_vector(
229 (sctp_random_param_t *)asoc->c.auth_random,
230 (sctp_chunks_param_t *)asoc->c.auth_chunks,
231 (sctp_hmac_algo_param_t *)asoc->c.auth_hmacs,
232 gfp);
233}
234
235/* Make a key vector based on peer's parameters */
236static struct sctp_auth_bytes *sctp_auth_make_peer_vector(
237 const struct sctp_association *asoc,
238 gfp_t gfp)
239{
240 return sctp_auth_make_key_vector(asoc->peer.peer_random,
241 asoc->peer.peer_chunks,
242 asoc->peer.peer_hmacs,
243 gfp);
244}
245
246
247/* Set the value of the association shared key base on the parameters
248 * given. The algorithm is:
249 * From the endpoint pair shared keys and the key vectors the
250 * association shared keys are computed. This is performed by selecting
251 * the numerically smaller key vector and concatenating it to the
252 * endpoint pair shared key, and then concatenating the numerically
253 * larger key vector to that. The result of the concatenation is the
254 * association shared key.
255 */
256static struct sctp_auth_bytes *sctp_auth_asoc_set_secret(
257 struct sctp_shared_key *ep_key,
258 struct sctp_auth_bytes *first_vector,
259 struct sctp_auth_bytes *last_vector,
260 gfp_t gfp)
261{
262 struct sctp_auth_bytes *secret;
263 __u32 offset = 0;
264 __u32 auth_len;
265
266 auth_len = first_vector->len + last_vector->len;
267 if (ep_key->key)
268 auth_len += ep_key->key->len;
269
270 secret = sctp_auth_create_key(auth_len, gfp);
271 if (!secret)
272 return NULL;
273
274 if (ep_key->key) {
275 memcpy(secret->data, ep_key->key->data, ep_key->key->len);
276 offset += ep_key->key->len;
277 }
278
279 memcpy(secret->data + offset, first_vector->data, first_vector->len);
280 offset += first_vector->len;
281
282 memcpy(secret->data + offset, last_vector->data, last_vector->len);
283
284 return secret;
285}
286
287/* Create an association shared key. Follow the algorithm
288 * described in SCTP-AUTH, Section 6.1
289 */
290static struct sctp_auth_bytes *sctp_auth_asoc_create_secret(
291 const struct sctp_association *asoc,
292 struct sctp_shared_key *ep_key,
293 gfp_t gfp)
294{
295 struct sctp_auth_bytes *local_key_vector;
296 struct sctp_auth_bytes *peer_key_vector;
297 struct sctp_auth_bytes *first_vector,
298 *last_vector;
299 struct sctp_auth_bytes *secret = NULL;
300 int cmp;
301
302
303 /* Now we need to build the key vectors
304 * SCTP-AUTH , Section 6.1
305 * The RANDOM parameter, the CHUNKS parameter and the HMAC-ALGO
306 * parameter sent by each endpoint are concatenated as byte vectors.
307 * These parameters include the parameter type, parameter length, and
308 * the parameter value, but padding is omitted; all padding MUST be
309 * removed from this concatenation before proceeding with further
310 * computation of keys. Parameters which were not sent are simply
311 * omitted from the concatenation process. The resulting two vectors
312 * are called the two key vectors.
313 */
314
315 local_key_vector = sctp_auth_make_local_vector(asoc, gfp);
316 peer_key_vector = sctp_auth_make_peer_vector(asoc, gfp);
317
318 if (!peer_key_vector || !local_key_vector)
319 goto out;
320
321 /* Figure out the order in which the key_vectors will be
322 * added to the endpoint shared key.
323 * SCTP-AUTH, Section 6.1:
324 * This is performed by selecting the numerically smaller key
325 * vector and concatenating it to the endpoint pair shared
326 * key, and then concatenating the numerically larger key
327 * vector to that. If the key vectors are equal as numbers
328 * but differ in length, then the concatenation order is the
329 * endpoint shared key, followed by the shorter key vector,
330 * followed by the longer key vector. Otherwise, the key
331 * vectors are identical, and may be concatenated to the
332 * endpoint pair key in any order.
333 */
334 cmp = sctp_auth_compare_vectors(local_key_vector,
335 peer_key_vector);
336 if (cmp < 0) {
337 first_vector = local_key_vector;
338 last_vector = peer_key_vector;
339 } else {
340 first_vector = peer_key_vector;
341 last_vector = local_key_vector;
342 }
343
344 secret = sctp_auth_asoc_set_secret(ep_key, first_vector, last_vector,
345 gfp);
346out:
347 sctp_auth_key_put(local_key_vector);
348 sctp_auth_key_put(peer_key_vector);
349
350 return secret;
351}
352
353/*
354 * Populate the association overlay list with the list
355 * from the endpoint.
356 */
357int sctp_auth_asoc_copy_shkeys(const struct sctp_endpoint *ep,
358 struct sctp_association *asoc,
359 gfp_t gfp)
360{
361 struct sctp_shared_key *sh_key;
362 struct sctp_shared_key *new;
363
364 BUG_ON(!list_empty(&asoc->endpoint_shared_keys));
365
366 key_for_each(sh_key, &ep->endpoint_shared_keys) {
367 new = sctp_auth_shkey_create(sh_key->key_id, gfp);
368 if (!new)
369 goto nomem;
370
371 new->key = sh_key->key;
372 sctp_auth_key_hold(new->key);
373 list_add(&new->key_list, &asoc->endpoint_shared_keys);
374 }
375
376 return 0;
377
378nomem:
379 sctp_auth_destroy_keys(&asoc->endpoint_shared_keys);
380 return -ENOMEM;
381}
382
383
384/* Public interface to creat the association shared key.
385 * See code above for the algorithm.
386 */
387int sctp_auth_asoc_init_active_key(struct sctp_association *asoc, gfp_t gfp)
388{
389 struct sctp_auth_bytes *secret;
390 struct sctp_shared_key *ep_key;
391
392 /* If we don't support AUTH, or peer is not capable
393 * we don't need to do anything.
394 */
395 if (!asoc->ep->auth_enable || !asoc->peer.auth_capable)
396 return 0;
397
398 /* If the key_id is non-zero and we couldn't find an
399 * endpoint pair shared key, we can't compute the
400 * secret.
401 * For key_id 0, endpoint pair shared key is a NULL key.
402 */
403 ep_key = sctp_auth_get_shkey(asoc, asoc->active_key_id);
404 BUG_ON(!ep_key);
405
406 secret = sctp_auth_asoc_create_secret(asoc, ep_key, gfp);
407 if (!secret)
408 return -ENOMEM;
409
410 sctp_auth_key_put(asoc->asoc_shared_key);
411 asoc->asoc_shared_key = secret;
412
413 return 0;
414}
415
416
417/* Find the endpoint pair shared key based on the key_id */
418struct sctp_shared_key *sctp_auth_get_shkey(
419 const struct sctp_association *asoc,
420 __u16 key_id)
421{
422 struct sctp_shared_key *key;
423
424 /* First search associations set of endpoint pair shared keys */
425 key_for_each(key, &asoc->endpoint_shared_keys) {
426 if (key->key_id == key_id)
427 return key;
428 }
429
430 return NULL;
431}
432
433/*
434 * Initialize all the possible digest transforms that we can use. Right now
435 * now, the supported digests are SHA1 and SHA256. We do this here once
436 * because of the restrictiong that transforms may only be allocated in
437 * user context. This forces us to pre-allocated all possible transforms
438 * at the endpoint init time.
439 */
440int sctp_auth_init_hmacs(struct sctp_endpoint *ep, gfp_t gfp)
441{
442 struct crypto_hash *tfm = NULL;
443 __u16 id;
444
445 /* If AUTH extension is disabled, we are done */
446 if (!ep->auth_enable) {
447 ep->auth_hmacs = NULL;
448 return 0;
449 }
450
451 /* If the transforms are already allocated, we are done */
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 successful 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 if (auth_hmacs[i])
503 crypto_free_hash(auth_hmacs[i]);
504 }
505 kfree(auth_hmacs);
506}
507
508
509struct sctp_hmac *sctp_auth_get_hmac(__u16 hmac_id)
510{
511 return &sctp_hmac_list[hmac_id];
512}
513
514/* Get an hmac description information that we can use to build
515 * the AUTH chunk
516 */
517struct sctp_hmac *sctp_auth_asoc_get_hmac(const struct sctp_association *asoc)
518{
519 struct sctp_hmac_algo_param *hmacs;
520 __u16 n_elt;
521 __u16 id = 0;
522 int i;
523
524 /* If we have a default entry, use it */
525 if (asoc->default_hmac_id)
526 return &sctp_hmac_list[asoc->default_hmac_id];
527
528 /* Since we do not have a default entry, find the first entry
529 * we support and return that. Do not cache that id.
530 */
531 hmacs = asoc->peer.peer_hmacs;
532 if (!hmacs)
533 return NULL;
534
535 n_elt = (ntohs(hmacs->param_hdr.length) - sizeof(sctp_paramhdr_t)) >> 1;
536 for (i = 0; i < n_elt; i++) {
537 id = ntohs(hmacs->hmac_ids[i]);
538
539 /* Check the id is in the supported range. And
540 * see if we support the id. Supported IDs have name and
541 * length fields set, so that we can allocate and use
542 * them. We can safely just check for name, for without the
543 * name, we can't allocate the TFM.
544 */
545 if (id > SCTP_AUTH_HMAC_ID_MAX ||
546 !sctp_hmac_list[id].hmac_name) {
547 id = 0;
548 continue;
549 }
550
551 break;
552 }
553
554 if (id == 0)
555 return NULL;
556
557 return &sctp_hmac_list[id];
558}
559
560static int __sctp_auth_find_hmacid(__be16 *hmacs, int n_elts, __be16 hmac_id)
561{
562 int found = 0;
563 int i;
564
565 for (i = 0; i < n_elts; i++) {
566 if (hmac_id == hmacs[i]) {
567 found = 1;
568 break;
569 }
570 }
571
572 return found;
573}
574
575/* See if the HMAC_ID is one that we claim as supported */
576int sctp_auth_asoc_verify_hmac_id(const struct sctp_association *asoc,
577 __be16 hmac_id)
578{
579 struct sctp_hmac_algo_param *hmacs;
580 __u16 n_elt;
581
582 if (!asoc)
583 return 0;
584
585 hmacs = (struct sctp_hmac_algo_param *)asoc->c.auth_hmacs;
586 n_elt = (ntohs(hmacs->param_hdr.length) - sizeof(sctp_paramhdr_t)) >> 1;
587
588 return __sctp_auth_find_hmacid(hmacs->hmac_ids, n_elt, hmac_id);
589}
590
591
592/* Cache the default HMAC id. This to follow this text from SCTP-AUTH:
593 * Section 6.1:
594 * The receiver of a HMAC-ALGO parameter SHOULD use the first listed
595 * algorithm it supports.
596 */
597void sctp_auth_asoc_set_default_hmac(struct sctp_association *asoc,
598 struct sctp_hmac_algo_param *hmacs)
599{
600 struct sctp_endpoint *ep;
601 __u16 id;
602 int i;
603 int n_params;
604
605 /* if the default id is already set, use it */
606 if (asoc->default_hmac_id)
607 return;
608
609 n_params = (ntohs(hmacs->param_hdr.length)
610 - sizeof(sctp_paramhdr_t)) >> 1;
611 ep = asoc->ep;
612 for (i = 0; i < n_params; i++) {
613 id = ntohs(hmacs->hmac_ids[i]);
614
615 /* Check the id is in the supported range */
616 if (id > SCTP_AUTH_HMAC_ID_MAX)
617 continue;
618
619 /* If this TFM has been allocated, use this id */
620 if (ep->auth_hmacs[id]) {
621 asoc->default_hmac_id = id;
622 break;
623 }
624 }
625}
626
627
628/* Check to see if the given chunk is supposed to be authenticated */
629static int __sctp_auth_cid(sctp_cid_t chunk, struct sctp_chunks_param *param)
630{
631 unsigned short len;
632 int found = 0;
633 int i;
634
635 if (!param || param->param_hdr.length == 0)
636 return 0;
637
638 len = ntohs(param->param_hdr.length) - sizeof(sctp_paramhdr_t);
639
640 /* SCTP-AUTH, Section 3.2
641 * The chunk types for INIT, INIT-ACK, SHUTDOWN-COMPLETE and AUTH
642 * chunks MUST NOT be listed in the CHUNKS parameter. However, if
643 * a CHUNKS parameter is received then the types for INIT, INIT-ACK,
644 * SHUTDOWN-COMPLETE and AUTH chunks MUST be ignored.
645 */
646 for (i = 0; !found && i < len; i++) {
647 switch (param->chunks[i]) {
648 case SCTP_CID_INIT:
649 case SCTP_CID_INIT_ACK:
650 case SCTP_CID_SHUTDOWN_COMPLETE:
651 case SCTP_CID_AUTH:
652 break;
653
654 default:
655 if (param->chunks[i] == chunk)
656 found = 1;
657 break;
658 }
659 }
660
661 return found;
662}
663
664/* Check if peer requested that this chunk is authenticated */
665int sctp_auth_send_cid(sctp_cid_t chunk, const struct sctp_association *asoc)
666{
667 if (!asoc)
668 return 0;
669
670 if (!asoc->ep->auth_enable || !asoc->peer.auth_capable)
671 return 0;
672
673 return __sctp_auth_cid(chunk, asoc->peer.peer_chunks);
674}
675
676/* Check if we requested that peer authenticate this chunk. */
677int sctp_auth_recv_cid(sctp_cid_t chunk, const struct sctp_association *asoc)
678{
679 if (!asoc)
680 return 0;
681
682 if (!asoc->ep->auth_enable)
683 return 0;
684
685 return __sctp_auth_cid(chunk,
686 (struct sctp_chunks_param *)asoc->c.auth_chunks);
687}
688
689/* SCTP-AUTH: Section 6.2:
690 * The sender MUST calculate the MAC as described in RFC2104 [2] using
691 * the hash function H as described by the MAC Identifier and the shared
692 * association key K based on the endpoint pair shared key described by
693 * the shared key identifier. The 'data' used for the computation of
694 * the AUTH-chunk is given by the AUTH chunk with its HMAC field set to
695 * zero (as shown in Figure 6) followed by all chunks that are placed
696 * after the AUTH chunk in the SCTP packet.
697 */
698void sctp_auth_calculate_hmac(const struct sctp_association *asoc,
699 struct sk_buff *skb,
700 struct sctp_auth_chunk *auth,
701 gfp_t gfp)
702{
703 struct scatterlist sg;
704 struct hash_desc desc;
705 struct sctp_auth_bytes *asoc_key;
706 __u16 key_id, hmac_id;
707 __u8 *digest;
708 unsigned char *end;
709 int free_key = 0;
710
711 /* Extract the info we need:
712 * - hmac id
713 * - key id
714 */
715 key_id = ntohs(auth->auth_hdr.shkey_id);
716 hmac_id = ntohs(auth->auth_hdr.hmac_id);
717
718 if (key_id == asoc->active_key_id)
719 asoc_key = asoc->asoc_shared_key;
720 else {
721 struct sctp_shared_key *ep_key;
722
723 ep_key = sctp_auth_get_shkey(asoc, key_id);
724 if (!ep_key)
725 return;
726
727 asoc_key = sctp_auth_asoc_create_secret(asoc, ep_key, gfp);
728 if (!asoc_key)
729 return;
730
731 free_key = 1;
732 }
733
734 /* set up scatter list */
735 end = skb_tail_pointer(skb);
736 sg_init_one(&sg, auth, end - (unsigned char *)auth);
737
738 desc.tfm = asoc->ep->auth_hmacs[hmac_id];
739 desc.flags = 0;
740
741 digest = auth->auth_hdr.hmac;
742 if (crypto_hash_setkey(desc.tfm, &asoc_key->data[0], asoc_key->len))
743 goto free;
744
745 crypto_hash_digest(&desc, &sg, sg.length, digest);
746
747free:
748 if (free_key)
749 sctp_auth_key_put(asoc_key);
750}
751
752/* API Helpers */
753
754/* Add a chunk to the endpoint authenticated chunk list */
755int sctp_auth_ep_add_chunkid(struct sctp_endpoint *ep, __u8 chunk_id)
756{
757 struct sctp_chunks_param *p = ep->auth_chunk_list;
758 __u16 nchunks;
759 __u16 param_len;
760
761 /* If this chunk is already specified, we are done */
762 if (__sctp_auth_cid(chunk_id, p))
763 return 0;
764
765 /* Check if we can add this chunk to the array */
766 param_len = ntohs(p->param_hdr.length);
767 nchunks = param_len - sizeof(sctp_paramhdr_t);
768 if (nchunks == SCTP_NUM_CHUNK_TYPES)
769 return -EINVAL;
770
771 p->chunks[nchunks] = chunk_id;
772 p->param_hdr.length = htons(param_len + 1);
773 return 0;
774}
775
776/* Add hmac identifires to the endpoint list of supported hmac ids */
777int sctp_auth_ep_set_hmacs(struct sctp_endpoint *ep,
778 struct sctp_hmacalgo *hmacs)
779{
780 int has_sha1 = 0;
781 __u16 id;
782 int i;
783
784 /* Scan the list looking for unsupported id. Also make sure that
785 * SHA1 is specified.
786 */
787 for (i = 0; i < hmacs->shmac_num_idents; i++) {
788 id = hmacs->shmac_idents[i];
789
790 if (id > SCTP_AUTH_HMAC_ID_MAX)
791 return -EOPNOTSUPP;
792
793 if (SCTP_AUTH_HMAC_ID_SHA1 == id)
794 has_sha1 = 1;
795
796 if (!sctp_hmac_list[id].hmac_name)
797 return -EOPNOTSUPP;
798 }
799
800 if (!has_sha1)
801 return -EINVAL;
802
803 memcpy(ep->auth_hmacs_list->hmac_ids, &hmacs->shmac_idents[0],
804 hmacs->shmac_num_idents * sizeof(__u16));
805 ep->auth_hmacs_list->param_hdr.length = htons(sizeof(sctp_paramhdr_t) +
806 hmacs->shmac_num_idents * sizeof(__u16));
807 return 0;
808}
809
810/* Set a new shared key on either endpoint or association. If the
811 * the key with a same ID already exists, replace the key (remove the
812 * old key and add a new one).
813 */
814int sctp_auth_set_key(struct sctp_endpoint *ep,
815 struct sctp_association *asoc,
816 struct sctp_authkey *auth_key)
817{
818 struct sctp_shared_key *cur_key = NULL;
819 struct sctp_auth_bytes *key;
820 struct list_head *sh_keys;
821 int replace = 0;
822
823 /* Try to find the given key id to see if
824 * we are doing a replace, or adding a new key
825 */
826 if (asoc)
827 sh_keys = &asoc->endpoint_shared_keys;
828 else
829 sh_keys = &ep->endpoint_shared_keys;
830
831 key_for_each(cur_key, sh_keys) {
832 if (cur_key->key_id == auth_key->sca_keynumber) {
833 replace = 1;
834 break;
835 }
836 }
837
838 /* If we are not replacing a key id, we need to allocate
839 * a shared key.
840 */
841 if (!replace) {
842 cur_key = sctp_auth_shkey_create(auth_key->sca_keynumber,
843 GFP_KERNEL);
844 if (!cur_key)
845 return -ENOMEM;
846 }
847
848 /* Create a new key data based on the info passed in */
849 key = sctp_auth_create_key(auth_key->sca_keylength, GFP_KERNEL);
850 if (!key)
851 goto nomem;
852
853 memcpy(key->data, &auth_key->sca_key[0], auth_key->sca_keylength);
854
855 /* If we are replacing, remove the old keys data from the
856 * key id. If we are adding new key id, add it to the
857 * list.
858 */
859 if (replace)
860 sctp_auth_key_put(cur_key->key);
861 else
862 list_add(&cur_key->key_list, sh_keys);
863
864 cur_key->key = key;
865 sctp_auth_key_hold(key);
866
867 return 0;
868nomem:
869 if (!replace)
870 sctp_auth_shkey_free(cur_key);
871
872 return -ENOMEM;
873}
874
875int sctp_auth_set_active_key(struct sctp_endpoint *ep,
876 struct sctp_association *asoc,
877 __u16 key_id)
878{
879 struct sctp_shared_key *key;
880 struct list_head *sh_keys;
881 int found = 0;
882
883 /* The key identifier MUST correst to an existing key */
884 if (asoc)
885 sh_keys = &asoc->endpoint_shared_keys;
886 else
887 sh_keys = &ep->endpoint_shared_keys;
888
889 key_for_each(key, sh_keys) {
890 if (key->key_id == key_id) {
891 found = 1;
892 break;
893 }
894 }
895
896 if (!found)
897 return -EINVAL;
898
899 if (asoc) {
900 asoc->active_key_id = key_id;
901 sctp_auth_asoc_init_active_key(asoc, GFP_KERNEL);
902 } else
903 ep->active_key_id = key_id;
904
905 return 0;
906}
907
908int sctp_auth_del_key_id(struct sctp_endpoint *ep,
909 struct sctp_association *asoc,
910 __u16 key_id)
911{
912 struct sctp_shared_key *key;
913 struct list_head *sh_keys;
914 int found = 0;
915
916 /* The key identifier MUST NOT be the current active key
917 * The key identifier MUST correst to an existing key
918 */
919 if (asoc) {
920 if (asoc->active_key_id == key_id)
921 return -EINVAL;
922
923 sh_keys = &asoc->endpoint_shared_keys;
924 } else {
925 if (ep->active_key_id == key_id)
926 return -EINVAL;
927
928 sh_keys = &ep->endpoint_shared_keys;
929 }
930
931 key_for_each(key, sh_keys) {
932 if (key->key_id == key_id) {
933 found = 1;
934 break;
935 }
936 }
937
938 if (!found)
939 return -EINVAL;
940
941 /* Delete the shared key */
942 list_del_init(&key->key_list);
943 sctp_auth_shkey_free(key);
944
945 return 0;
946}
1/* SCTP kernel implementation
2 * (C) Copyright 2007 Hewlett-Packard Development Company, L.P.
3 *
4 * This file is part of the SCTP kernel implementation
5 *
6 * This SCTP 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 * This SCTP 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/slab.h>
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
44static 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 },
58#if defined (CONFIG_CRYPTO_SHA256) || defined (CONFIG_CRYPTO_SHA256_MODULE)
59 {
60 .hmac_id = SCTP_AUTH_HMAC_ID_SHA256,
61 .hmac_name="hmac(sha256)",
62 .hmac_len = SCTP_SHA256_SIG_SIZE,
63 }
64#endif
65};
66
67
68void 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 */
80static struct sctp_auth_bytes *sctp_auth_create_key(__u32 key_len, gfp_t gfp)
81{
82 struct sctp_auth_bytes *key;
83
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
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 */
101struct 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
116/* Free the shared key structure */
117static void sctp_auth_shkey_free(struct sctp_shared_key *sh_key)
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
125/* Destroy the entire key list. This is done during the
126 * associon and endpoint free process.
127 */
128void 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
145 * < 0 - vector 1 is smaller than vector2
146 * > 0 - vector 1 is greater than vector2
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 */
158static 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 */
194static 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 */
230static struct sctp_auth_bytes *sctp_auth_make_local_vector(
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 */
242static struct sctp_auth_bytes *sctp_auth_make_peer_vector(
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 */
262static 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 */
296static 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
327 /* Figure out the order in which the key_vectors will be
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);
352out:
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 */
363int 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
384nomem:
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 */
393int 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 */
424struct sctp_shared_key *sctp_auth_get_shkey(
425 const struct sctp_association *asoc,
426 __u16 key_id)
427{
428 struct sctp_shared_key *key;
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)
433 return key;
434 }
435
436 return NULL;
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 */
446int 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
492out_err:
493 /* Clean up any successful allocations */
494 sctp_auth_destroy_hmacs(ep->auth_hmacs);
495 return -ENOMEM;
496}
497
498/* Destroy the hmac tfm array */
499void 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
515struct 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 */
523struct 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 */
546 if (id > SCTP_AUTH_HMAC_ID_MAX) {
547 id = 0;
548 continue;
549 }
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 */
556 if (!sctp_hmac_list[id].hmac_name) {
557 id = 0;
558 continue;
559 }
560
561 break;
562 }
563
564 if (id == 0)
565 return NULL;
566
567 return &sctp_hmac_list[id];
568}
569
570static int __sctp_auth_find_hmacid(__be16 *hmacs, int n_elts, __be16 hmac_id)
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 */
586int sctp_auth_asoc_verify_hmac_id(const struct sctp_association *asoc,
587 __be16 hmac_id)
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 */
607void 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 */
639static 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
645 if (!param || param->param_hdr.length == 0)
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 */
675int 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. */
684int 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 */
702void 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);
740 sg_init_one(&sg, auth, end - (unsigned char *)auth);
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
751free:
752 if (free_key)
753 sctp_auth_key_put(asoc_key);
754}
755
756/* API Helpers */
757
758/* Add a chunk to the endpoint authenticated chunk list */
759int 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 */
781int 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
794 if (id > SCTP_AUTH_HMAC_ID_MAX)
795 return -EOPNOTSUPP;
796
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 */
818int 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 */
853 key = sctp_auth_create_key(auth_key->sca_keylength, GFP_KERNEL);
854 if (!key)
855 goto nomem;
856
857 memcpy(key->data, &auth_key->sca_key[0], auth_key->sca_keylength);
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;
872nomem:
873 if (!replace)
874 sctp_auth_shkey_free(cur_key);
875
876 return -ENOMEM;
877}
878
879int 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
912int 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}