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1// SPDX-License-Identifier: GPL-2.0-or-later
2/* SCTP kernel implementation
3 * (C) Copyright 2007 Hewlett-Packard Development Company, L.P.
4 *
5 * This file is part of the SCTP kernel implementation
6 *
7 * Please send any bug reports or fixes you make to the
8 * email address(es):
9 * lksctp developers <linux-sctp@vger.kernel.org>
10 *
11 * Written or modified by:
12 * Vlad Yasevich <vladislav.yasevich@hp.com>
13 */
14
15#include <crypto/hash.h>
16#include <linux/slab.h>
17#include <linux/types.h>
18#include <linux/scatterlist.h>
19#include <net/sctp/sctp.h>
20#include <net/sctp/auth.h>
21
22static struct sctp_hmac sctp_hmac_list[SCTP_AUTH_NUM_HMACS] = {
23 {
24 /* id 0 is reserved. as all 0 */
25 .hmac_id = SCTP_AUTH_HMAC_ID_RESERVED_0,
26 },
27 {
28 .hmac_id = SCTP_AUTH_HMAC_ID_SHA1,
29 .hmac_name = "hmac(sha1)",
30 .hmac_len = SCTP_SHA1_SIG_SIZE,
31 },
32 {
33 /* id 2 is reserved as well */
34 .hmac_id = SCTP_AUTH_HMAC_ID_RESERVED_2,
35 },
36#if IS_ENABLED(CONFIG_CRYPTO_SHA256)
37 {
38 .hmac_id = SCTP_AUTH_HMAC_ID_SHA256,
39 .hmac_name = "hmac(sha256)",
40 .hmac_len = SCTP_SHA256_SIG_SIZE,
41 }
42#endif
43};
44
45
46void sctp_auth_key_put(struct sctp_auth_bytes *key)
47{
48 if (!key)
49 return;
50
51 if (refcount_dec_and_test(&key->refcnt)) {
52 kzfree(key);
53 SCTP_DBG_OBJCNT_DEC(keys);
54 }
55}
56
57/* Create a new key structure of a given length */
58static struct sctp_auth_bytes *sctp_auth_create_key(__u32 key_len, gfp_t gfp)
59{
60 struct sctp_auth_bytes *key;
61
62 /* Verify that we are not going to overflow INT_MAX */
63 if (key_len > (INT_MAX - sizeof(struct sctp_auth_bytes)))
64 return NULL;
65
66 /* Allocate the shared key */
67 key = kmalloc(sizeof(struct sctp_auth_bytes) + key_len, gfp);
68 if (!key)
69 return NULL;
70
71 key->len = key_len;
72 refcount_set(&key->refcnt, 1);
73 SCTP_DBG_OBJCNT_INC(keys);
74
75 return key;
76}
77
78/* Create a new shared key container with a give key id */
79struct sctp_shared_key *sctp_auth_shkey_create(__u16 key_id, gfp_t gfp)
80{
81 struct sctp_shared_key *new;
82
83 /* Allocate the shared key container */
84 new = kzalloc(sizeof(struct sctp_shared_key), gfp);
85 if (!new)
86 return NULL;
87
88 INIT_LIST_HEAD(&new->key_list);
89 refcount_set(&new->refcnt, 1);
90 new->key_id = key_id;
91
92 return new;
93}
94
95/* Free the shared key structure */
96static void sctp_auth_shkey_destroy(struct sctp_shared_key *sh_key)
97{
98 BUG_ON(!list_empty(&sh_key->key_list));
99 sctp_auth_key_put(sh_key->key);
100 sh_key->key = NULL;
101 kfree(sh_key);
102}
103
104void sctp_auth_shkey_release(struct sctp_shared_key *sh_key)
105{
106 if (refcount_dec_and_test(&sh_key->refcnt))
107 sctp_auth_shkey_destroy(sh_key);
108}
109
110void sctp_auth_shkey_hold(struct sctp_shared_key *sh_key)
111{
112 refcount_inc(&sh_key->refcnt);
113}
114
115/* Destroy the entire key list. This is done during the
116 * associon and endpoint free process.
117 */
118void sctp_auth_destroy_keys(struct list_head *keys)
119{
120 struct sctp_shared_key *ep_key;
121 struct sctp_shared_key *tmp;
122
123 if (list_empty(keys))
124 return;
125
126 key_for_each_safe(ep_key, tmp, keys) {
127 list_del_init(&ep_key->key_list);
128 sctp_auth_shkey_release(ep_key);
129 }
130}
131
132/* Compare two byte vectors as numbers. Return values
133 * are:
134 * 0 - vectors are equal
135 * < 0 - vector 1 is smaller than vector2
136 * > 0 - vector 1 is greater than vector2
137 *
138 * Algorithm is:
139 * This is performed by selecting the numerically smaller key vector...
140 * If the key vectors are equal as numbers but differ in length ...
141 * the shorter vector is considered smaller
142 *
143 * Examples (with small values):
144 * 000123456789 > 123456789 (first number is longer)
145 * 000123456789 < 234567891 (second number is larger numerically)
146 * 123456789 > 2345678 (first number is both larger & longer)
147 */
148static int sctp_auth_compare_vectors(struct sctp_auth_bytes *vector1,
149 struct sctp_auth_bytes *vector2)
150{
151 int diff;
152 int i;
153 const __u8 *longer;
154
155 diff = vector1->len - vector2->len;
156 if (diff) {
157 longer = (diff > 0) ? vector1->data : vector2->data;
158
159 /* Check to see if the longer number is
160 * lead-zero padded. If it is not, it
161 * is automatically larger numerically.
162 */
163 for (i = 0; i < abs(diff); i++) {
164 if (longer[i] != 0)
165 return diff;
166 }
167 }
168
169 /* lengths are the same, compare numbers */
170 return memcmp(vector1->data, vector2->data, vector1->len);
171}
172
173/*
174 * Create a key vector as described in SCTP-AUTH, Section 6.1
175 * The RANDOM parameter, the CHUNKS parameter and the HMAC-ALGO
176 * parameter sent by each endpoint are concatenated as byte vectors.
177 * These parameters include the parameter type, parameter length, and
178 * the parameter value, but padding is omitted; all padding MUST be
179 * removed from this concatenation before proceeding with further
180 * computation of keys. Parameters which were not sent are simply
181 * omitted from the concatenation process. The resulting two vectors
182 * are called the two key vectors.
183 */
184static struct sctp_auth_bytes *sctp_auth_make_key_vector(
185 struct sctp_random_param *random,
186 struct sctp_chunks_param *chunks,
187 struct sctp_hmac_algo_param *hmacs,
188 gfp_t gfp)
189{
190 struct sctp_auth_bytes *new;
191 __u32 len;
192 __u32 offset = 0;
193 __u16 random_len, hmacs_len, chunks_len = 0;
194
195 random_len = ntohs(random->param_hdr.length);
196 hmacs_len = ntohs(hmacs->param_hdr.length);
197 if (chunks)
198 chunks_len = ntohs(chunks->param_hdr.length);
199
200 len = random_len + hmacs_len + chunks_len;
201
202 new = sctp_auth_create_key(len, gfp);
203 if (!new)
204 return NULL;
205
206 memcpy(new->data, random, random_len);
207 offset += random_len;
208
209 if (chunks) {
210 memcpy(new->data + offset, chunks, chunks_len);
211 offset += chunks_len;
212 }
213
214 memcpy(new->data + offset, hmacs, hmacs_len);
215
216 return new;
217}
218
219
220/* Make a key vector based on our local parameters */
221static struct sctp_auth_bytes *sctp_auth_make_local_vector(
222 const struct sctp_association *asoc,
223 gfp_t gfp)
224{
225 return sctp_auth_make_key_vector(
226 (struct sctp_random_param *)asoc->c.auth_random,
227 (struct sctp_chunks_param *)asoc->c.auth_chunks,
228 (struct sctp_hmac_algo_param *)asoc->c.auth_hmacs, gfp);
229}
230
231/* Make a key vector based on peer's parameters */
232static struct sctp_auth_bytes *sctp_auth_make_peer_vector(
233 const struct sctp_association *asoc,
234 gfp_t gfp)
235{
236 return sctp_auth_make_key_vector(asoc->peer.peer_random,
237 asoc->peer.peer_chunks,
238 asoc->peer.peer_hmacs,
239 gfp);
240}
241
242
243/* Set the value of the association shared key base on the parameters
244 * given. The algorithm is:
245 * From the endpoint pair shared keys and the key vectors the
246 * association shared keys are computed. This is performed by selecting
247 * the numerically smaller key vector and concatenating it to the
248 * endpoint pair shared key, and then concatenating the numerically
249 * larger key vector to that. The result of the concatenation is the
250 * association shared key.
251 */
252static struct sctp_auth_bytes *sctp_auth_asoc_set_secret(
253 struct sctp_shared_key *ep_key,
254 struct sctp_auth_bytes *first_vector,
255 struct sctp_auth_bytes *last_vector,
256 gfp_t gfp)
257{
258 struct sctp_auth_bytes *secret;
259 __u32 offset = 0;
260 __u32 auth_len;
261
262 auth_len = first_vector->len + last_vector->len;
263 if (ep_key->key)
264 auth_len += ep_key->key->len;
265
266 secret = sctp_auth_create_key(auth_len, gfp);
267 if (!secret)
268 return NULL;
269
270 if (ep_key->key) {
271 memcpy(secret->data, ep_key->key->data, ep_key->key->len);
272 offset += ep_key->key->len;
273 }
274
275 memcpy(secret->data + offset, first_vector->data, first_vector->len);
276 offset += first_vector->len;
277
278 memcpy(secret->data + offset, last_vector->data, last_vector->len);
279
280 return secret;
281}
282
283/* Create an association shared key. Follow the algorithm
284 * described in SCTP-AUTH, Section 6.1
285 */
286static struct sctp_auth_bytes *sctp_auth_asoc_create_secret(
287 const struct sctp_association *asoc,
288 struct sctp_shared_key *ep_key,
289 gfp_t gfp)
290{
291 struct sctp_auth_bytes *local_key_vector;
292 struct sctp_auth_bytes *peer_key_vector;
293 struct sctp_auth_bytes *first_vector,
294 *last_vector;
295 struct sctp_auth_bytes *secret = NULL;
296 int cmp;
297
298
299 /* Now we need to build the key vectors
300 * SCTP-AUTH , Section 6.1
301 * The RANDOM parameter, the CHUNKS parameter and the HMAC-ALGO
302 * parameter sent by each endpoint are concatenated as byte vectors.
303 * These parameters include the parameter type, parameter length, and
304 * the parameter value, but padding is omitted; all padding MUST be
305 * removed from this concatenation before proceeding with further
306 * computation of keys. Parameters which were not sent are simply
307 * omitted from the concatenation process. The resulting two vectors
308 * are called the two key vectors.
309 */
310
311 local_key_vector = sctp_auth_make_local_vector(asoc, gfp);
312 peer_key_vector = sctp_auth_make_peer_vector(asoc, gfp);
313
314 if (!peer_key_vector || !local_key_vector)
315 goto out;
316
317 /* Figure out the order in which the key_vectors will be
318 * added to the endpoint shared key.
319 * SCTP-AUTH, Section 6.1:
320 * This is performed by selecting the numerically smaller key
321 * vector and concatenating it to the endpoint pair shared
322 * key, and then concatenating the numerically larger key
323 * vector to that. If the key vectors are equal as numbers
324 * but differ in length, then the concatenation order is the
325 * endpoint shared key, followed by the shorter key vector,
326 * followed by the longer key vector. Otherwise, the key
327 * vectors are identical, and may be concatenated to the
328 * endpoint pair key in any order.
329 */
330 cmp = sctp_auth_compare_vectors(local_key_vector,
331 peer_key_vector);
332 if (cmp < 0) {
333 first_vector = local_key_vector;
334 last_vector = peer_key_vector;
335 } else {
336 first_vector = peer_key_vector;
337 last_vector = local_key_vector;
338 }
339
340 secret = sctp_auth_asoc_set_secret(ep_key, first_vector, last_vector,
341 gfp);
342out:
343 sctp_auth_key_put(local_key_vector);
344 sctp_auth_key_put(peer_key_vector);
345
346 return secret;
347}
348
349/*
350 * Populate the association overlay list with the list
351 * from the endpoint.
352 */
353int sctp_auth_asoc_copy_shkeys(const struct sctp_endpoint *ep,
354 struct sctp_association *asoc,
355 gfp_t gfp)
356{
357 struct sctp_shared_key *sh_key;
358 struct sctp_shared_key *new;
359
360 BUG_ON(!list_empty(&asoc->endpoint_shared_keys));
361
362 key_for_each(sh_key, &ep->endpoint_shared_keys) {
363 new = sctp_auth_shkey_create(sh_key->key_id, gfp);
364 if (!new)
365 goto nomem;
366
367 new->key = sh_key->key;
368 sctp_auth_key_hold(new->key);
369 list_add(&new->key_list, &asoc->endpoint_shared_keys);
370 }
371
372 return 0;
373
374nomem:
375 sctp_auth_destroy_keys(&asoc->endpoint_shared_keys);
376 return -ENOMEM;
377}
378
379
380/* Public interface to create the association shared key.
381 * See code above for the algorithm.
382 */
383int sctp_auth_asoc_init_active_key(struct sctp_association *asoc, gfp_t gfp)
384{
385 struct sctp_auth_bytes *secret;
386 struct sctp_shared_key *ep_key;
387 struct sctp_chunk *chunk;
388
389 /* If we don't support AUTH, or peer is not capable
390 * we don't need to do anything.
391 */
392 if (!asoc->peer.auth_capable)
393 return 0;
394
395 /* If the key_id is non-zero and we couldn't find an
396 * endpoint pair shared key, we can't compute the
397 * secret.
398 * For key_id 0, endpoint pair shared key is a NULL key.
399 */
400 ep_key = sctp_auth_get_shkey(asoc, asoc->active_key_id);
401 BUG_ON(!ep_key);
402
403 secret = sctp_auth_asoc_create_secret(asoc, ep_key, gfp);
404 if (!secret)
405 return -ENOMEM;
406
407 sctp_auth_key_put(asoc->asoc_shared_key);
408 asoc->asoc_shared_key = secret;
409 asoc->shkey = ep_key;
410
411 /* Update send queue in case any chunk already in there now
412 * needs authenticating
413 */
414 list_for_each_entry(chunk, &asoc->outqueue.out_chunk_list, list) {
415 if (sctp_auth_send_cid(chunk->chunk_hdr->type, asoc)) {
416 chunk->auth = 1;
417 if (!chunk->shkey) {
418 chunk->shkey = asoc->shkey;
419 sctp_auth_shkey_hold(chunk->shkey);
420 }
421 }
422 }
423
424 return 0;
425}
426
427
428/* Find the endpoint pair shared key based on the key_id */
429struct sctp_shared_key *sctp_auth_get_shkey(
430 const struct sctp_association *asoc,
431 __u16 key_id)
432{
433 struct sctp_shared_key *key;
434
435 /* First search associations set of endpoint pair shared keys */
436 key_for_each(key, &asoc->endpoint_shared_keys) {
437 if (key->key_id == key_id) {
438 if (!key->deactivated)
439 return key;
440 break;
441 }
442 }
443
444 return NULL;
445}
446
447/*
448 * Initialize all the possible digest transforms that we can use. Right now
449 * now, the supported digests are SHA1 and SHA256. We do this here once
450 * because of the restrictiong that transforms may only be allocated in
451 * user context. This forces us to pre-allocated all possible transforms
452 * at the endpoint init time.
453 */
454int sctp_auth_init_hmacs(struct sctp_endpoint *ep, gfp_t gfp)
455{
456 struct crypto_shash *tfm = NULL;
457 __u16 id;
458
459 /* If the transforms are already allocated, we are done */
460 if (ep->auth_hmacs)
461 return 0;
462
463 /* Allocated the array of pointers to transorms */
464 ep->auth_hmacs = kcalloc(SCTP_AUTH_NUM_HMACS,
465 sizeof(struct crypto_shash *),
466 gfp);
467 if (!ep->auth_hmacs)
468 return -ENOMEM;
469
470 for (id = 0; id < SCTP_AUTH_NUM_HMACS; id++) {
471
472 /* See is we support the id. Supported IDs have name and
473 * length fields set, so that we can allocated and use
474 * them. We can safely just check for name, for without the
475 * name, we can't allocate the TFM.
476 */
477 if (!sctp_hmac_list[id].hmac_name)
478 continue;
479
480 /* If this TFM has been allocated, we are all set */
481 if (ep->auth_hmacs[id])
482 continue;
483
484 /* Allocate the ID */
485 tfm = crypto_alloc_shash(sctp_hmac_list[id].hmac_name, 0, 0);
486 if (IS_ERR(tfm))
487 goto out_err;
488
489 ep->auth_hmacs[id] = tfm;
490 }
491
492 return 0;
493
494out_err:
495 /* Clean up any successful allocations */
496 sctp_auth_destroy_hmacs(ep->auth_hmacs);
497 return -ENOMEM;
498}
499
500/* Destroy the hmac tfm array */
501void sctp_auth_destroy_hmacs(struct crypto_shash *auth_hmacs[])
502{
503 int i;
504
505 if (!auth_hmacs)
506 return;
507
508 for (i = 0; i < SCTP_AUTH_NUM_HMACS; i++) {
509 crypto_free_shash(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) -
542 sizeof(struct sctp_paramhdr)) >> 1;
543 for (i = 0; i < n_elt; i++) {
544 id = ntohs(hmacs->hmac_ids[i]);
545
546 /* Check the id is in the supported range. And
547 * see if we support the id. Supported IDs have name and
548 * length fields set, so that we can allocate and use
549 * them. We can safely just check for name, for without the
550 * name, we can't allocate the TFM.
551 */
552 if (id > SCTP_AUTH_HMAC_ID_MAX ||
553 !sctp_hmac_list[id].hmac_name) {
554 id = 0;
555 continue;
556 }
557
558 break;
559 }
560
561 if (id == 0)
562 return NULL;
563
564 return &sctp_hmac_list[id];
565}
566
567static int __sctp_auth_find_hmacid(__be16 *hmacs, int n_elts, __be16 hmac_id)
568{
569 int found = 0;
570 int i;
571
572 for (i = 0; i < n_elts; i++) {
573 if (hmac_id == hmacs[i]) {
574 found = 1;
575 break;
576 }
577 }
578
579 return found;
580}
581
582/* See if the HMAC_ID is one that we claim as supported */
583int sctp_auth_asoc_verify_hmac_id(const struct sctp_association *asoc,
584 __be16 hmac_id)
585{
586 struct sctp_hmac_algo_param *hmacs;
587 __u16 n_elt;
588
589 if (!asoc)
590 return 0;
591
592 hmacs = (struct sctp_hmac_algo_param *)asoc->c.auth_hmacs;
593 n_elt = (ntohs(hmacs->param_hdr.length) -
594 sizeof(struct sctp_paramhdr)) >> 1;
595
596 return __sctp_auth_find_hmacid(hmacs->hmac_ids, n_elt, hmac_id);
597}
598
599
600/* Cache the default HMAC id. This to follow this text from SCTP-AUTH:
601 * Section 6.1:
602 * The receiver of a HMAC-ALGO parameter SHOULD use the first listed
603 * algorithm it supports.
604 */
605void sctp_auth_asoc_set_default_hmac(struct sctp_association *asoc,
606 struct sctp_hmac_algo_param *hmacs)
607{
608 struct sctp_endpoint *ep;
609 __u16 id;
610 int i;
611 int n_params;
612
613 /* if the default id is already set, use it */
614 if (asoc->default_hmac_id)
615 return;
616
617 n_params = (ntohs(hmacs->param_hdr.length) -
618 sizeof(struct sctp_paramhdr)) >> 1;
619 ep = asoc->ep;
620 for (i = 0; i < n_params; i++) {
621 id = ntohs(hmacs->hmac_ids[i]);
622
623 /* Check the id is in the supported range */
624 if (id > SCTP_AUTH_HMAC_ID_MAX)
625 continue;
626
627 /* If this TFM has been allocated, use this id */
628 if (ep->auth_hmacs[id]) {
629 asoc->default_hmac_id = id;
630 break;
631 }
632 }
633}
634
635
636/* Check to see if the given chunk is supposed to be authenticated */
637static int __sctp_auth_cid(enum sctp_cid chunk, struct sctp_chunks_param *param)
638{
639 unsigned short len;
640 int found = 0;
641 int i;
642
643 if (!param || param->param_hdr.length == 0)
644 return 0;
645
646 len = ntohs(param->param_hdr.length) - sizeof(struct sctp_paramhdr);
647
648 /* SCTP-AUTH, Section 3.2
649 * The chunk types for INIT, INIT-ACK, SHUTDOWN-COMPLETE and AUTH
650 * chunks MUST NOT be listed in the CHUNKS parameter. However, if
651 * a CHUNKS parameter is received then the types for INIT, INIT-ACK,
652 * SHUTDOWN-COMPLETE and AUTH chunks MUST be ignored.
653 */
654 for (i = 0; !found && i < len; i++) {
655 switch (param->chunks[i]) {
656 case SCTP_CID_INIT:
657 case SCTP_CID_INIT_ACK:
658 case SCTP_CID_SHUTDOWN_COMPLETE:
659 case SCTP_CID_AUTH:
660 break;
661
662 default:
663 if (param->chunks[i] == chunk)
664 found = 1;
665 break;
666 }
667 }
668
669 return found;
670}
671
672/* Check if peer requested that this chunk is authenticated */
673int sctp_auth_send_cid(enum sctp_cid chunk, const struct sctp_association *asoc)
674{
675 if (!asoc)
676 return 0;
677
678 if (!asoc->peer.auth_capable)
679 return 0;
680
681 return __sctp_auth_cid(chunk, asoc->peer.peer_chunks);
682}
683
684/* Check if we requested that peer authenticate this chunk. */
685int sctp_auth_recv_cid(enum sctp_cid chunk, const struct sctp_association *asoc)
686{
687 if (!asoc)
688 return 0;
689
690 if (!asoc->peer.auth_capable)
691 return 0;
692
693 return __sctp_auth_cid(chunk,
694 (struct sctp_chunks_param *)asoc->c.auth_chunks);
695}
696
697/* SCTP-AUTH: Section 6.2:
698 * The sender MUST calculate the MAC as described in RFC2104 [2] using
699 * the hash function H as described by the MAC Identifier and the shared
700 * association key K based on the endpoint pair shared key described by
701 * the shared key identifier. The 'data' used for the computation of
702 * the AUTH-chunk is given by the AUTH chunk with its HMAC field set to
703 * zero (as shown in Figure 6) followed by all chunks that are placed
704 * after the AUTH chunk in the SCTP packet.
705 */
706void sctp_auth_calculate_hmac(const struct sctp_association *asoc,
707 struct sk_buff *skb, struct sctp_auth_chunk *auth,
708 struct sctp_shared_key *ep_key, gfp_t gfp)
709{
710 struct sctp_auth_bytes *asoc_key;
711 struct crypto_shash *tfm;
712 __u16 key_id, hmac_id;
713 unsigned char *end;
714 int free_key = 0;
715 __u8 *digest;
716
717 /* Extract the info we need:
718 * - hmac id
719 * - key id
720 */
721 key_id = ntohs(auth->auth_hdr.shkey_id);
722 hmac_id = ntohs(auth->auth_hdr.hmac_id);
723
724 if (key_id == asoc->active_key_id)
725 asoc_key = asoc->asoc_shared_key;
726 else {
727 /* ep_key can't be NULL here */
728 asoc_key = sctp_auth_asoc_create_secret(asoc, ep_key, gfp);
729 if (!asoc_key)
730 return;
731
732 free_key = 1;
733 }
734
735 /* set up scatter list */
736 end = skb_tail_pointer(skb);
737
738 tfm = asoc->ep->auth_hmacs[hmac_id];
739
740 digest = auth->auth_hdr.hmac;
741 if (crypto_shash_setkey(tfm, &asoc_key->data[0], asoc_key->len))
742 goto free;
743
744 {
745 SHASH_DESC_ON_STACK(desc, tfm);
746
747 desc->tfm = tfm;
748 crypto_shash_digest(desc, (u8 *)auth,
749 end - (unsigned char *)auth, digest);
750 shash_desc_zero(desc);
751 }
752
753free:
754 if (free_key)
755 sctp_auth_key_put(asoc_key);
756}
757
758/* API Helpers */
759
760/* Add a chunk to the endpoint authenticated chunk list */
761int sctp_auth_ep_add_chunkid(struct sctp_endpoint *ep, __u8 chunk_id)
762{
763 struct sctp_chunks_param *p = ep->auth_chunk_list;
764 __u16 nchunks;
765 __u16 param_len;
766
767 /* If this chunk is already specified, we are done */
768 if (__sctp_auth_cid(chunk_id, p))
769 return 0;
770
771 /* Check if we can add this chunk to the array */
772 param_len = ntohs(p->param_hdr.length);
773 nchunks = param_len - sizeof(struct sctp_paramhdr);
774 if (nchunks == SCTP_NUM_CHUNK_TYPES)
775 return -EINVAL;
776
777 p->chunks[nchunks] = chunk_id;
778 p->param_hdr.length = htons(param_len + 1);
779 return 0;
780}
781
782/* Add hmac identifires to the endpoint list of supported hmac ids */
783int sctp_auth_ep_set_hmacs(struct sctp_endpoint *ep,
784 struct sctp_hmacalgo *hmacs)
785{
786 int has_sha1 = 0;
787 __u16 id;
788 int i;
789
790 /* Scan the list looking for unsupported id. Also make sure that
791 * SHA1 is specified.
792 */
793 for (i = 0; i < hmacs->shmac_num_idents; i++) {
794 id = hmacs->shmac_idents[i];
795
796 if (id > SCTP_AUTH_HMAC_ID_MAX)
797 return -EOPNOTSUPP;
798
799 if (SCTP_AUTH_HMAC_ID_SHA1 == id)
800 has_sha1 = 1;
801
802 if (!sctp_hmac_list[id].hmac_name)
803 return -EOPNOTSUPP;
804 }
805
806 if (!has_sha1)
807 return -EINVAL;
808
809 for (i = 0; i < hmacs->shmac_num_idents; i++)
810 ep->auth_hmacs_list->hmac_ids[i] =
811 htons(hmacs->shmac_idents[i]);
812 ep->auth_hmacs_list->param_hdr.length =
813 htons(sizeof(struct sctp_paramhdr) +
814 hmacs->shmac_num_idents * sizeof(__u16));
815 return 0;
816}
817
818/* Set a new shared key on either endpoint or association. If the
819 * the key with a same ID already exists, replace the key (remove the
820 * old key and add a new one).
821 */
822int sctp_auth_set_key(struct sctp_endpoint *ep,
823 struct sctp_association *asoc,
824 struct sctp_authkey *auth_key)
825{
826 struct sctp_shared_key *cur_key, *shkey;
827 struct sctp_auth_bytes *key;
828 struct list_head *sh_keys;
829 int replace = 0;
830
831 /* Try to find the given key id to see if
832 * we are doing a replace, or adding a new key
833 */
834 if (asoc) {
835 if (!asoc->peer.auth_capable)
836 return -EACCES;
837 sh_keys = &asoc->endpoint_shared_keys;
838 } else {
839 if (!ep->auth_enable)
840 return -EACCES;
841 sh_keys = &ep->endpoint_shared_keys;
842 }
843
844 key_for_each(shkey, sh_keys) {
845 if (shkey->key_id == auth_key->sca_keynumber) {
846 replace = 1;
847 break;
848 }
849 }
850
851 cur_key = sctp_auth_shkey_create(auth_key->sca_keynumber, GFP_KERNEL);
852 if (!cur_key)
853 return -ENOMEM;
854
855 /* Create a new key data based on the info passed in */
856 key = sctp_auth_create_key(auth_key->sca_keylength, GFP_KERNEL);
857 if (!key) {
858 kfree(cur_key);
859 return -ENOMEM;
860 }
861
862 memcpy(key->data, &auth_key->sca_key[0], auth_key->sca_keylength);
863 cur_key->key = key;
864
865 if (replace) {
866 list_del_init(&shkey->key_list);
867 sctp_auth_shkey_release(shkey);
868 }
869 list_add(&cur_key->key_list, sh_keys);
870
871 return 0;
872}
873
874int sctp_auth_set_active_key(struct sctp_endpoint *ep,
875 struct sctp_association *asoc,
876 __u16 key_id)
877{
878 struct sctp_shared_key *key;
879 struct list_head *sh_keys;
880 int found = 0;
881
882 /* The key identifier MUST correst to an existing key */
883 if (asoc) {
884 if (!asoc->peer.auth_capable)
885 return -EACCES;
886 sh_keys = &asoc->endpoint_shared_keys;
887 } else {
888 if (!ep->auth_enable)
889 return -EACCES;
890 sh_keys = &ep->endpoint_shared_keys;
891 }
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 || key->deactivated)
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->peer.auth_capable)
925 return -EACCES;
926 if (asoc->active_key_id == key_id)
927 return -EINVAL;
928
929 sh_keys = &asoc->endpoint_shared_keys;
930 } else {
931 if (!ep->auth_enable)
932 return -EACCES;
933 if (ep->active_key_id == key_id)
934 return -EINVAL;
935
936 sh_keys = &ep->endpoint_shared_keys;
937 }
938
939 key_for_each(key, sh_keys) {
940 if (key->key_id == key_id) {
941 found = 1;
942 break;
943 }
944 }
945
946 if (!found)
947 return -EINVAL;
948
949 /* Delete the shared key */
950 list_del_init(&key->key_list);
951 sctp_auth_shkey_release(key);
952
953 return 0;
954}
955
956int sctp_auth_deact_key_id(struct sctp_endpoint *ep,
957 struct sctp_association *asoc, __u16 key_id)
958{
959 struct sctp_shared_key *key;
960 struct list_head *sh_keys;
961 int found = 0;
962
963 /* The key identifier MUST NOT be the current active key
964 * The key identifier MUST correst to an existing key
965 */
966 if (asoc) {
967 if (!asoc->peer.auth_capable)
968 return -EACCES;
969 if (asoc->active_key_id == key_id)
970 return -EINVAL;
971
972 sh_keys = &asoc->endpoint_shared_keys;
973 } else {
974 if (!ep->auth_enable)
975 return -EACCES;
976 if (ep->active_key_id == key_id)
977 return -EINVAL;
978
979 sh_keys = &ep->endpoint_shared_keys;
980 }
981
982 key_for_each(key, sh_keys) {
983 if (key->key_id == key_id) {
984 found = 1;
985 break;
986 }
987 }
988
989 if (!found)
990 return -EINVAL;
991
992 /* refcnt == 1 and !list_empty mean it's not being used anywhere
993 * and deactivated will be set, so it's time to notify userland
994 * that this shkey can be freed.
995 */
996 if (asoc && !list_empty(&key->key_list) &&
997 refcount_read(&key->refcnt) == 1) {
998 struct sctp_ulpevent *ev;
999
1000 ev = sctp_ulpevent_make_authkey(asoc, key->key_id,
1001 SCTP_AUTH_FREE_KEY, GFP_KERNEL);
1002 if (ev)
1003 asoc->stream.si->enqueue_event(&asoc->ulpq, ev);
1004 }
1005
1006 key->deactivated = 1;
1007
1008 return 0;
1009}
1010
1011int sctp_auth_init(struct sctp_endpoint *ep, gfp_t gfp)
1012{
1013 int err = -ENOMEM;
1014
1015 /* Allocate space for HMACS and CHUNKS authentication
1016 * variables. There are arrays that we encode directly
1017 * into parameters to make the rest of the operations easier.
1018 */
1019 if (!ep->auth_hmacs_list) {
1020 struct sctp_hmac_algo_param *auth_hmacs;
1021
1022 auth_hmacs = kzalloc(struct_size(auth_hmacs, hmac_ids,
1023 SCTP_AUTH_NUM_HMACS), gfp);
1024 if (!auth_hmacs)
1025 goto nomem;
1026 /* Initialize the HMACS parameter.
1027 * SCTP-AUTH: Section 3.3
1028 * Every endpoint supporting SCTP chunk authentication MUST
1029 * support the HMAC based on the SHA-1 algorithm.
1030 */
1031 auth_hmacs->param_hdr.type = SCTP_PARAM_HMAC_ALGO;
1032 auth_hmacs->param_hdr.length =
1033 htons(sizeof(struct sctp_paramhdr) + 2);
1034 auth_hmacs->hmac_ids[0] = htons(SCTP_AUTH_HMAC_ID_SHA1);
1035 ep->auth_hmacs_list = auth_hmacs;
1036 }
1037
1038 if (!ep->auth_chunk_list) {
1039 struct sctp_chunks_param *auth_chunks;
1040
1041 auth_chunks = kzalloc(sizeof(*auth_chunks) +
1042 SCTP_NUM_CHUNK_TYPES, gfp);
1043 if (!auth_chunks)
1044 goto nomem;
1045 /* Initialize the CHUNKS parameter */
1046 auth_chunks->param_hdr.type = SCTP_PARAM_CHUNKS;
1047 auth_chunks->param_hdr.length =
1048 htons(sizeof(struct sctp_paramhdr));
1049 ep->auth_chunk_list = auth_chunks;
1050 }
1051
1052 /* Allocate and initialize transorms arrays for supported
1053 * HMACs.
1054 */
1055 err = sctp_auth_init_hmacs(ep, gfp);
1056 if (err)
1057 goto nomem;
1058
1059 return 0;
1060
1061nomem:
1062 /* Free all allocations */
1063 kfree(ep->auth_hmacs_list);
1064 kfree(ep->auth_chunk_list);
1065 ep->auth_hmacs_list = NULL;
1066 ep->auth_chunk_list = NULL;
1067 return err;
1068}
1069
1070void sctp_auth_free(struct sctp_endpoint *ep)
1071{
1072 kfree(ep->auth_hmacs_list);
1073 kfree(ep->auth_chunk_list);
1074 ep->auth_hmacs_list = NULL;
1075 ep->auth_chunk_list = NULL;
1076 sctp_auth_destroy_hmacs(ep->auth_hmacs);
1077 ep->auth_hmacs = NULL;
1078}
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 <crypto/hash.h>
31#include <linux/slab.h>
32#include <linux/types.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 IS_ENABLED(CONFIG_CRYPTO_SHA256)
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 create 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 struct sctp_chunk *chunk;
392
393 /* If we don't support AUTH, or peer is not capable
394 * we don't need to do anything.
395 */
396 if (!asoc->ep->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 /* Update send queue in case any chunk already in there now
415 * needs authenticating
416 */
417 list_for_each_entry(chunk, &asoc->outqueue.out_chunk_list, list) {
418 if (sctp_auth_send_cid(chunk->chunk_hdr->type, asoc))
419 chunk->auth = 1;
420 }
421
422 return 0;
423}
424
425
426/* Find the endpoint pair shared key based on the key_id */
427struct sctp_shared_key *sctp_auth_get_shkey(
428 const struct sctp_association *asoc,
429 __u16 key_id)
430{
431 struct sctp_shared_key *key;
432
433 /* First search associations set of endpoint pair shared keys */
434 key_for_each(key, &asoc->endpoint_shared_keys) {
435 if (key->key_id == key_id)
436 return key;
437 }
438
439 return NULL;
440}
441
442/*
443 * Initialize all the possible digest transforms that we can use. Right now
444 * now, the supported digests are SHA1 and SHA256. We do this here once
445 * because of the restrictiong that transforms may only be allocated in
446 * user context. This forces us to pre-allocated all possible transforms
447 * at the endpoint init time.
448 */
449int sctp_auth_init_hmacs(struct sctp_endpoint *ep, gfp_t gfp)
450{
451 struct crypto_shash *tfm = NULL;
452 __u16 id;
453
454 /* If AUTH extension is disabled, we are done */
455 if (!ep->auth_enable) {
456 ep->auth_hmacs = NULL;
457 return 0;
458 }
459
460 /* If the transforms are already allocated, we are done */
461 if (ep->auth_hmacs)
462 return 0;
463
464 /* Allocated the array of pointers to transorms */
465 ep->auth_hmacs = kzalloc(sizeof(struct crypto_shash *) *
466 SCTP_AUTH_NUM_HMACS, gfp);
467 if (!ep->auth_hmacs)
468 return -ENOMEM;
469
470 for (id = 0; id < SCTP_AUTH_NUM_HMACS; id++) {
471
472 /* See is we support the id. Supported IDs have name and
473 * length fields set, so that we can allocated and use
474 * them. We can safely just check for name, for without the
475 * name, we can't allocate the TFM.
476 */
477 if (!sctp_hmac_list[id].hmac_name)
478 continue;
479
480 /* If this TFM has been allocated, we are all set */
481 if (ep->auth_hmacs[id])
482 continue;
483
484 /* Allocate the ID */
485 tfm = crypto_alloc_shash(sctp_hmac_list[id].hmac_name, 0, 0);
486 if (IS_ERR(tfm))
487 goto out_err;
488
489 ep->auth_hmacs[id] = tfm;
490 }
491
492 return 0;
493
494out_err:
495 /* Clean up any successful allocations */
496 sctp_auth_destroy_hmacs(ep->auth_hmacs);
497 return -ENOMEM;
498}
499
500/* Destroy the hmac tfm array */
501void sctp_auth_destroy_hmacs(struct crypto_shash *auth_hmacs[])
502{
503 int i;
504
505 if (!auth_hmacs)
506 return;
507
508 for (i = 0; i < SCTP_AUTH_NUM_HMACS; i++) {
509 crypto_free_shash(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. And
546 * see if we support the id. Supported IDs have name and
547 * length fields set, so that we can allocate and use
548 * them. We can safely just check for name, for without the
549 * name, we can't allocate the TFM.
550 */
551 if (id > SCTP_AUTH_HMAC_ID_MAX ||
552 !sctp_hmac_list[id].hmac_name) {
553 id = 0;
554 continue;
555 }
556
557 break;
558 }
559
560 if (id == 0)
561 return NULL;
562
563 return &sctp_hmac_list[id];
564}
565
566static int __sctp_auth_find_hmacid(__be16 *hmacs, int n_elts, __be16 hmac_id)
567{
568 int found = 0;
569 int i;
570
571 for (i = 0; i < n_elts; i++) {
572 if (hmac_id == hmacs[i]) {
573 found = 1;
574 break;
575 }
576 }
577
578 return found;
579}
580
581/* See if the HMAC_ID is one that we claim as supported */
582int sctp_auth_asoc_verify_hmac_id(const struct sctp_association *asoc,
583 __be16 hmac_id)
584{
585 struct sctp_hmac_algo_param *hmacs;
586 __u16 n_elt;
587
588 if (!asoc)
589 return 0;
590
591 hmacs = (struct sctp_hmac_algo_param *)asoc->c.auth_hmacs;
592 n_elt = (ntohs(hmacs->param_hdr.length) - sizeof(sctp_paramhdr_t)) >> 1;
593
594 return __sctp_auth_find_hmacid(hmacs->hmac_ids, n_elt, hmac_id);
595}
596
597
598/* Cache the default HMAC id. This to follow this text from SCTP-AUTH:
599 * Section 6.1:
600 * The receiver of a HMAC-ALGO parameter SHOULD use the first listed
601 * algorithm it supports.
602 */
603void sctp_auth_asoc_set_default_hmac(struct sctp_association *asoc,
604 struct sctp_hmac_algo_param *hmacs)
605{
606 struct sctp_endpoint *ep;
607 __u16 id;
608 int i;
609 int n_params;
610
611 /* if the default id is already set, use it */
612 if (asoc->default_hmac_id)
613 return;
614
615 n_params = (ntohs(hmacs->param_hdr.length)
616 - sizeof(sctp_paramhdr_t)) >> 1;
617 ep = asoc->ep;
618 for (i = 0; i < n_params; i++) {
619 id = ntohs(hmacs->hmac_ids[i]);
620
621 /* Check the id is in the supported range */
622 if (id > SCTP_AUTH_HMAC_ID_MAX)
623 continue;
624
625 /* If this TFM has been allocated, use this id */
626 if (ep->auth_hmacs[id]) {
627 asoc->default_hmac_id = id;
628 break;
629 }
630 }
631}
632
633
634/* Check to see if the given chunk is supposed to be authenticated */
635static int __sctp_auth_cid(sctp_cid_t chunk, struct sctp_chunks_param *param)
636{
637 unsigned short len;
638 int found = 0;
639 int i;
640
641 if (!param || param->param_hdr.length == 0)
642 return 0;
643
644 len = ntohs(param->param_hdr.length) - sizeof(sctp_paramhdr_t);
645
646 /* SCTP-AUTH, Section 3.2
647 * The chunk types for INIT, INIT-ACK, SHUTDOWN-COMPLETE and AUTH
648 * chunks MUST NOT be listed in the CHUNKS parameter. However, if
649 * a CHUNKS parameter is received then the types for INIT, INIT-ACK,
650 * SHUTDOWN-COMPLETE and AUTH chunks MUST be ignored.
651 */
652 for (i = 0; !found && i < len; i++) {
653 switch (param->chunks[i]) {
654 case SCTP_CID_INIT:
655 case SCTP_CID_INIT_ACK:
656 case SCTP_CID_SHUTDOWN_COMPLETE:
657 case SCTP_CID_AUTH:
658 break;
659
660 default:
661 if (param->chunks[i] == chunk)
662 found = 1;
663 break;
664 }
665 }
666
667 return found;
668}
669
670/* Check if peer requested that this chunk is authenticated */
671int sctp_auth_send_cid(sctp_cid_t chunk, const struct sctp_association *asoc)
672{
673 if (!asoc)
674 return 0;
675
676 if (!asoc->ep->auth_enable || !asoc->peer.auth_capable)
677 return 0;
678
679 return __sctp_auth_cid(chunk, asoc->peer.peer_chunks);
680}
681
682/* Check if we requested that peer authenticate this chunk. */
683int sctp_auth_recv_cid(sctp_cid_t chunk, const struct sctp_association *asoc)
684{
685 if (!asoc)
686 return 0;
687
688 if (!asoc->ep->auth_enable)
689 return 0;
690
691 return __sctp_auth_cid(chunk,
692 (struct sctp_chunks_param *)asoc->c.auth_chunks);
693}
694
695/* SCTP-AUTH: Section 6.2:
696 * The sender MUST calculate the MAC as described in RFC2104 [2] using
697 * the hash function H as described by the MAC Identifier and the shared
698 * association key K based on the endpoint pair shared key described by
699 * the shared key identifier. The 'data' used for the computation of
700 * the AUTH-chunk is given by the AUTH chunk with its HMAC field set to
701 * zero (as shown in Figure 6) followed by all chunks that are placed
702 * after the AUTH chunk in the SCTP packet.
703 */
704void sctp_auth_calculate_hmac(const struct sctp_association *asoc,
705 struct sk_buff *skb,
706 struct sctp_auth_chunk *auth,
707 gfp_t gfp)
708{
709 struct crypto_shash *tfm;
710 struct sctp_auth_bytes *asoc_key;
711 __u16 key_id, hmac_id;
712 __u8 *digest;
713 unsigned char *end;
714 int free_key = 0;
715
716 /* Extract the info we need:
717 * - hmac id
718 * - key id
719 */
720 key_id = ntohs(auth->auth_hdr.shkey_id);
721 hmac_id = ntohs(auth->auth_hdr.hmac_id);
722
723 if (key_id == asoc->active_key_id)
724 asoc_key = asoc->asoc_shared_key;
725 else {
726 struct sctp_shared_key *ep_key;
727
728 ep_key = sctp_auth_get_shkey(asoc, key_id);
729 if (!ep_key)
730 return;
731
732 asoc_key = sctp_auth_asoc_create_secret(asoc, ep_key, gfp);
733 if (!asoc_key)
734 return;
735
736 free_key = 1;
737 }
738
739 /* set up scatter list */
740 end = skb_tail_pointer(skb);
741
742 tfm = asoc->ep->auth_hmacs[hmac_id];
743
744 digest = auth->auth_hdr.hmac;
745 if (crypto_shash_setkey(tfm, &asoc_key->data[0], asoc_key->len))
746 goto free;
747
748 {
749 SHASH_DESC_ON_STACK(desc, tfm);
750
751 desc->tfm = tfm;
752 desc->flags = 0;
753 crypto_shash_digest(desc, (u8 *)auth,
754 end - (unsigned char *)auth, digest);
755 shash_desc_zero(desc);
756 }
757
758free:
759 if (free_key)
760 sctp_auth_key_put(asoc_key);
761}
762
763/* API Helpers */
764
765/* Add a chunk to the endpoint authenticated chunk list */
766int sctp_auth_ep_add_chunkid(struct sctp_endpoint *ep, __u8 chunk_id)
767{
768 struct sctp_chunks_param *p = ep->auth_chunk_list;
769 __u16 nchunks;
770 __u16 param_len;
771
772 /* If this chunk is already specified, we are done */
773 if (__sctp_auth_cid(chunk_id, p))
774 return 0;
775
776 /* Check if we can add this chunk to the array */
777 param_len = ntohs(p->param_hdr.length);
778 nchunks = param_len - sizeof(sctp_paramhdr_t);
779 if (nchunks == SCTP_NUM_CHUNK_TYPES)
780 return -EINVAL;
781
782 p->chunks[nchunks] = chunk_id;
783 p->param_hdr.length = htons(param_len + 1);
784 return 0;
785}
786
787/* Add hmac identifires to the endpoint list of supported hmac ids */
788int sctp_auth_ep_set_hmacs(struct sctp_endpoint *ep,
789 struct sctp_hmacalgo *hmacs)
790{
791 int has_sha1 = 0;
792 __u16 id;
793 int i;
794
795 /* Scan the list looking for unsupported id. Also make sure that
796 * SHA1 is specified.
797 */
798 for (i = 0; i < hmacs->shmac_num_idents; i++) {
799 id = hmacs->shmac_idents[i];
800
801 if (id > SCTP_AUTH_HMAC_ID_MAX)
802 return -EOPNOTSUPP;
803
804 if (SCTP_AUTH_HMAC_ID_SHA1 == id)
805 has_sha1 = 1;
806
807 if (!sctp_hmac_list[id].hmac_name)
808 return -EOPNOTSUPP;
809 }
810
811 if (!has_sha1)
812 return -EINVAL;
813
814 for (i = 0; i < hmacs->shmac_num_idents; i++)
815 ep->auth_hmacs_list->hmac_ids[i] = htons(hmacs->shmac_idents[i]);
816 ep->auth_hmacs_list->param_hdr.length = htons(sizeof(sctp_paramhdr_t) +
817 hmacs->shmac_num_idents * sizeof(__u16));
818 return 0;
819}
820
821/* Set a new shared key on either endpoint or association. If the
822 * the key with a same ID already exists, replace the key (remove the
823 * old key and add a new one).
824 */
825int sctp_auth_set_key(struct sctp_endpoint *ep,
826 struct sctp_association *asoc,
827 struct sctp_authkey *auth_key)
828{
829 struct sctp_shared_key *cur_key = NULL;
830 struct sctp_auth_bytes *key;
831 struct list_head *sh_keys;
832 int replace = 0;
833
834 /* Try to find the given key id to see if
835 * we are doing a replace, or adding a new key
836 */
837 if (asoc)
838 sh_keys = &asoc->endpoint_shared_keys;
839 else
840 sh_keys = &ep->endpoint_shared_keys;
841
842 key_for_each(cur_key, sh_keys) {
843 if (cur_key->key_id == auth_key->sca_keynumber) {
844 replace = 1;
845 break;
846 }
847 }
848
849 /* If we are not replacing a key id, we need to allocate
850 * a shared key.
851 */
852 if (!replace) {
853 cur_key = sctp_auth_shkey_create(auth_key->sca_keynumber,
854 GFP_KERNEL);
855 if (!cur_key)
856 return -ENOMEM;
857 }
858
859 /* Create a new key data based on the info passed in */
860 key = sctp_auth_create_key(auth_key->sca_keylength, GFP_KERNEL);
861 if (!key)
862 goto nomem;
863
864 memcpy(key->data, &auth_key->sca_key[0], auth_key->sca_keylength);
865
866 /* If we are replacing, remove the old keys data from the
867 * key id. If we are adding new key id, add it to the
868 * list.
869 */
870 if (replace)
871 sctp_auth_key_put(cur_key->key);
872 else
873 list_add(&cur_key->key_list, sh_keys);
874
875 cur_key->key = key;
876 return 0;
877nomem:
878 if (!replace)
879 sctp_auth_shkey_free(cur_key);
880
881 return -ENOMEM;
882}
883
884int sctp_auth_set_active_key(struct sctp_endpoint *ep,
885 struct sctp_association *asoc,
886 __u16 key_id)
887{
888 struct sctp_shared_key *key;
889 struct list_head *sh_keys;
890 int found = 0;
891
892 /* The key identifier MUST correst to an existing key */
893 if (asoc)
894 sh_keys = &asoc->endpoint_shared_keys;
895 else
896 sh_keys = &ep->endpoint_shared_keys;
897
898 key_for_each(key, sh_keys) {
899 if (key->key_id == key_id) {
900 found = 1;
901 break;
902 }
903 }
904
905 if (!found)
906 return -EINVAL;
907
908 if (asoc) {
909 asoc->active_key_id = key_id;
910 sctp_auth_asoc_init_active_key(asoc, GFP_KERNEL);
911 } else
912 ep->active_key_id = key_id;
913
914 return 0;
915}
916
917int sctp_auth_del_key_id(struct sctp_endpoint *ep,
918 struct sctp_association *asoc,
919 __u16 key_id)
920{
921 struct sctp_shared_key *key;
922 struct list_head *sh_keys;
923 int found = 0;
924
925 /* The key identifier MUST NOT be the current active key
926 * The key identifier MUST correst to an existing key
927 */
928 if (asoc) {
929 if (asoc->active_key_id == key_id)
930 return -EINVAL;
931
932 sh_keys = &asoc->endpoint_shared_keys;
933 } else {
934 if (ep->active_key_id == key_id)
935 return -EINVAL;
936
937 sh_keys = &ep->endpoint_shared_keys;
938 }
939
940 key_for_each(key, sh_keys) {
941 if (key->key_id == key_id) {
942 found = 1;
943 break;
944 }
945 }
946
947 if (!found)
948 return -EINVAL;
949
950 /* Delete the shared key */
951 list_del_init(&key->key_list);
952 sctp_auth_shkey_free(key);
953
954 return 0;
955}