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
22 static 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
46 void 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 kfree_sensitive(key);
53 SCTP_DBG_OBJCNT_DEC(keys);
54 }
55 }
56
57 /* Create a new key structure of a given length */
58 static 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 */
79 struct 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 */
96 static 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
104 void 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
110 void 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 */
118 void 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 */
148 static 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 */
184 static 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 */
221 static 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 */
232 static 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 */
252 static 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 */
286 static 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);
342 out:
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 */
353 int 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
374 nomem:
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 */
383 int 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 */
429 struct 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
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 */
454 int 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
494 out_err:
495 /* Clean up any successful allocations */
496 sctp_auth_destroy_hmacs(ep->auth_hmacs);
497 ep->auth_hmacs = NULL;
498 return -ENOMEM;
499 }
500
501 /* Destroy the hmac tfm array */
502 void sctp_auth_destroy_hmacs(struct crypto_shash *auth_hmacs[])
503 {
504 int i;
505
506 if (!auth_hmacs)
507 return;
508
509 for (i = 0; i < SCTP_AUTH_NUM_HMACS; i++) {
510 crypto_free_shash(auth_hmacs[i]);
511 }
512 kfree(auth_hmacs);
513 }
514
515
516 struct sctp_hmac *sctp_auth_get_hmac(__u16 hmac_id)
517 {
518 return &sctp_hmac_list[hmac_id];
519 }
520
521 /* Get an hmac description information that we can use to build
522 * the AUTH chunk
523 */
524 struct sctp_hmac *sctp_auth_asoc_get_hmac(const struct sctp_association *asoc)
525 {
526 struct sctp_hmac_algo_param *hmacs;
527 __u16 n_elt;
528 __u16 id = 0;
529 int i;
530
531 /* If we have a default entry, use it */
532 if (asoc->default_hmac_id)
533 return &sctp_hmac_list[asoc->default_hmac_id];
534
535 /* Since we do not have a default entry, find the first entry
536 * we support and return that. Do not cache that id.
537 */
538 hmacs = asoc->peer.peer_hmacs;
539 if (!hmacs)
540 return NULL;
541
542 n_elt = (ntohs(hmacs->param_hdr.length) -
543 sizeof(struct sctp_paramhdr)) >> 1;
544 for (i = 0; i < n_elt; i++) {
545 id = ntohs(hmacs->hmac_ids[i]);
546
547 /* Check the id is in the supported range. And
548 * see if we support the id. Supported IDs have name and
549 * length fields set, so that we can allocate and use
550 * them. We can safely just check for name, for without the
551 * name, we can't allocate the TFM.
552 */
553 if (id > SCTP_AUTH_HMAC_ID_MAX ||
554 !sctp_hmac_list[id].hmac_name) {
555 id = 0;
556 continue;
557 }
558
559 break;
560 }
561
562 if (id == 0)
563 return NULL;
564
565 return &sctp_hmac_list[id];
566 }
567
568 static int __sctp_auth_find_hmacid(__be16 *hmacs, int n_elts, __be16 hmac_id)
569 {
570 int found = 0;
571 int i;
572
573 for (i = 0; i < n_elts; i++) {
574 if (hmac_id == hmacs[i]) {
575 found = 1;
576 break;
577 }
578 }
579
580 return found;
581 }
582
583 /* See if the HMAC_ID is one that we claim as supported */
584 int sctp_auth_asoc_verify_hmac_id(const struct sctp_association *asoc,
585 __be16 hmac_id)
586 {
587 struct sctp_hmac_algo_param *hmacs;
588 __u16 n_elt;
589
590 if (!asoc)
591 return 0;
592
593 hmacs = (struct sctp_hmac_algo_param *)asoc->c.auth_hmacs;
594 n_elt = (ntohs(hmacs->param_hdr.length) -
595 sizeof(struct sctp_paramhdr)) >> 1;
596
597 return __sctp_auth_find_hmacid(hmacs->hmac_ids, n_elt, hmac_id);
598 }
599
600
601 /* Cache the default HMAC id. This to follow this text from SCTP-AUTH:
602 * Section 6.1:
603 * The receiver of a HMAC-ALGO parameter SHOULD use the first listed
604 * algorithm it supports.
605 */
606 void sctp_auth_asoc_set_default_hmac(struct sctp_association *asoc,
607 struct sctp_hmac_algo_param *hmacs)
608 {
609 struct sctp_endpoint *ep;
610 __u16 id;
611 int i;
612 int n_params;
613
614 /* if the default id is already set, use it */
615 if (asoc->default_hmac_id)
616 return;
617
618 n_params = (ntohs(hmacs->param_hdr.length) -
619 sizeof(struct sctp_paramhdr)) >> 1;
620 ep = asoc->ep;
621 for (i = 0; i < n_params; i++) {
622 id = ntohs(hmacs->hmac_ids[i]);
623
624 /* Check the id is in the supported range */
625 if (id > SCTP_AUTH_HMAC_ID_MAX)
626 continue;
627
628 /* If this TFM has been allocated, use this id */
629 if (ep->auth_hmacs[id]) {
630 asoc->default_hmac_id = id;
631 break;
632 }
633 }
634 }
635
636
637 /* Check to see if the given chunk is supposed to be authenticated */
638 static int __sctp_auth_cid(enum sctp_cid chunk, struct sctp_chunks_param *param)
639 {
640 unsigned short len;
641 int found = 0;
642 int i;
643
644 if (!param || param->param_hdr.length == 0)
645 return 0;
646
647 len = ntohs(param->param_hdr.length) - sizeof(struct sctp_paramhdr);
648
649 /* SCTP-AUTH, Section 3.2
650 * The chunk types for INIT, INIT-ACK, SHUTDOWN-COMPLETE and AUTH
651 * chunks MUST NOT be listed in the CHUNKS parameter. However, if
652 * a CHUNKS parameter is received then the types for INIT, INIT-ACK,
653 * SHUTDOWN-COMPLETE and AUTH chunks MUST be ignored.
654 */
655 for (i = 0; !found && i < len; i++) {
656 switch (param->chunks[i]) {
657 case SCTP_CID_INIT:
658 case SCTP_CID_INIT_ACK:
659 case SCTP_CID_SHUTDOWN_COMPLETE:
660 case SCTP_CID_AUTH:
661 break;
662
663 default:
664 if (param->chunks[i] == chunk)
665 found = 1;
666 break;
667 }
668 }
669
670 return found;
671 }
672
673 /* Check if peer requested that this chunk is authenticated */
674 int sctp_auth_send_cid(enum sctp_cid chunk, const struct sctp_association *asoc)
675 {
676 if (!asoc)
677 return 0;
678
679 if (!asoc->peer.auth_capable)
680 return 0;
681
682 return __sctp_auth_cid(chunk, asoc->peer.peer_chunks);
683 }
684
685 /* Check if we requested that peer authenticate this chunk. */
686 int sctp_auth_recv_cid(enum sctp_cid chunk, const struct sctp_association *asoc)
687 {
688 if (!asoc)
689 return 0;
690
691 if (!asoc->peer.auth_capable)
692 return 0;
693
694 return __sctp_auth_cid(chunk,
695 (struct sctp_chunks_param *)asoc->c.auth_chunks);
696 }
697
698 /* SCTP-AUTH: Section 6.2:
699 * The sender MUST calculate the MAC as described in RFC2104 [2] using
700 * the hash function H as described by the MAC Identifier and the shared
701 * association key K based on the endpoint pair shared key described by
702 * the shared key identifier. The 'data' used for the computation of
703 * the AUTH-chunk is given by the AUTH chunk with its HMAC field set to
704 * zero (as shown in Figure 6) followed by all chunks that are placed
705 * after the AUTH chunk in the SCTP packet.
706 */
707 void sctp_auth_calculate_hmac(const struct sctp_association *asoc,
708 struct sk_buff *skb, struct sctp_auth_chunk *auth,
709 struct sctp_shared_key *ep_key, gfp_t gfp)
710 {
711 struct sctp_auth_bytes *asoc_key;
712 struct crypto_shash *tfm;
713 __u16 key_id, hmac_id;
714 unsigned char *end;
715 int free_key = 0;
716 __u8 *digest;
717
718 /* Extract the info we need:
719 * - hmac id
720 * - key id
721 */
722 key_id = ntohs(auth->auth_hdr.shkey_id);
723 hmac_id = ntohs(auth->auth_hdr.hmac_id);
724
725 if (key_id == asoc->active_key_id)
726 asoc_key = asoc->asoc_shared_key;
727 else {
728 /* ep_key can't be NULL here */
729 asoc_key = sctp_auth_asoc_create_secret(asoc, ep_key, gfp);
730 if (!asoc_key)
731 return;
732
733 free_key = 1;
734 }
735
736 /* set up scatter list */
737 end = skb_tail_pointer(skb);
738
739 tfm = asoc->ep->auth_hmacs[hmac_id];
740
741 digest = (u8 *)(&auth->auth_hdr + 1);
742 if (crypto_shash_setkey(tfm, &asoc_key->data[0], asoc_key->len))
743 goto free;
744
745 crypto_shash_tfm_digest(tfm, (u8 *)auth, end - (unsigned char *)auth,
746 digest);
747
748 free:
749 if (free_key)
750 sctp_auth_key_put(asoc_key);
751 }
752
753 /* API Helpers */
754
755 /* Add a chunk to the endpoint authenticated chunk list */
756 int sctp_auth_ep_add_chunkid(struct sctp_endpoint *ep, __u8 chunk_id)
757 {
758 struct sctp_chunks_param *p = ep->auth_chunk_list;
759 __u16 nchunks;
760 __u16 param_len;
761
762 /* If this chunk is already specified, we are done */
763 if (__sctp_auth_cid(chunk_id, p))
764 return 0;
765
766 /* Check if we can add this chunk to the array */
767 param_len = ntohs(p->param_hdr.length);
768 nchunks = param_len - sizeof(struct sctp_paramhdr);
769 if (nchunks == SCTP_NUM_CHUNK_TYPES)
770 return -EINVAL;
771
772 p->chunks[nchunks] = chunk_id;
773 p->param_hdr.length = htons(param_len + 1);
774 return 0;
775 }
776
777 /* Add hmac identifires to the endpoint list of supported hmac ids */
778 int sctp_auth_ep_set_hmacs(struct sctp_endpoint *ep,
779 struct sctp_hmacalgo *hmacs)
780 {
781 int has_sha1 = 0;
782 __u16 id;
783 int i;
784
785 /* Scan the list looking for unsupported id. Also make sure that
786 * SHA1 is specified.
787 */
788 for (i = 0; i < hmacs->shmac_num_idents; i++) {
789 id = hmacs->shmac_idents[i];
790
791 if (id > SCTP_AUTH_HMAC_ID_MAX)
792 return -EOPNOTSUPP;
793
794 if (SCTP_AUTH_HMAC_ID_SHA1 == id)
795 has_sha1 = 1;
796
797 if (!sctp_hmac_list[id].hmac_name)
798 return -EOPNOTSUPP;
799 }
800
801 if (!has_sha1)
802 return -EINVAL;
803
804 for (i = 0; i < hmacs->shmac_num_idents; i++)
805 ep->auth_hmacs_list->hmac_ids[i] =
806 htons(hmacs->shmac_idents[i]);
807 ep->auth_hmacs_list->param_hdr.length =
808 htons(sizeof(struct sctp_paramhdr) +
809 hmacs->shmac_num_idents * sizeof(__u16));
810 return 0;
811 }
812
813 /* Set a new shared key on either endpoint or association. If the
814 * key with a same ID already exists, replace the key (remove the
815 * old key and add a new one).
816 */
817 int sctp_auth_set_key(struct sctp_endpoint *ep,
818 struct sctp_association *asoc,
819 struct sctp_authkey *auth_key)
820 {
821 struct sctp_shared_key *cur_key, *shkey;
822 struct sctp_auth_bytes *key;
823 struct list_head *sh_keys;
824 int replace = 0;
825
826 /* Try to find the given key id to see if
827 * we are doing a replace, or adding a new key
828 */
829 if (asoc) {
830 if (!asoc->peer.auth_capable)
831 return -EACCES;
832 sh_keys = &asoc->endpoint_shared_keys;
833 } else {
834 if (!ep->auth_enable)
835 return -EACCES;
836 sh_keys = &ep->endpoint_shared_keys;
837 }
838
839 key_for_each(shkey, sh_keys) {
840 if (shkey->key_id == auth_key->sca_keynumber) {
841 replace = 1;
842 break;
843 }
844 }
845
846 cur_key = sctp_auth_shkey_create(auth_key->sca_keynumber, GFP_KERNEL);
847 if (!cur_key)
848 return -ENOMEM;
849
850 /* Create a new key data based on the info passed in */
851 key = sctp_auth_create_key(auth_key->sca_keylength, GFP_KERNEL);
852 if (!key) {
853 kfree(cur_key);
854 return -ENOMEM;
855 }
856
857 memcpy(key->data, &auth_key->sca_key[0], auth_key->sca_keylength);
858 cur_key->key = key;
859
860 if (!replace) {
861 list_add(&cur_key->key_list, sh_keys);
862 return 0;
863 }
864
865 list_del_init(&shkey->key_list);
866 list_add(&cur_key->key_list, sh_keys);
867
868 if (asoc && asoc->active_key_id == auth_key->sca_keynumber &&
869 sctp_auth_asoc_init_active_key(asoc, GFP_KERNEL)) {
870 list_del_init(&cur_key->key_list);
871 sctp_auth_shkey_release(cur_key);
872 list_add(&shkey->key_list, sh_keys);
873 return -ENOMEM;
874 }
875
876 sctp_auth_shkey_release(shkey);
877 return 0;
878 }
879
880 int sctp_auth_set_active_key(struct sctp_endpoint *ep,
881 struct sctp_association *asoc,
882 __u16 key_id)
883 {
884 struct sctp_shared_key *key;
885 struct list_head *sh_keys;
886 int found = 0;
887
888 /* The key identifier MUST correst to an existing key */
889 if (asoc) {
890 if (!asoc->peer.auth_capable)
891 return -EACCES;
892 sh_keys = &asoc->endpoint_shared_keys;
893 } else {
894 if (!ep->auth_enable)
895 return -EACCES;
896 sh_keys = &ep->endpoint_shared_keys;
897 }
898
899 key_for_each(key, sh_keys) {
900 if (key->key_id == key_id) {
901 found = 1;
902 break;
903 }
904 }
905
906 if (!found || key->deactivated)
907 return -EINVAL;
908
909 if (asoc) {
910 __u16 active_key_id = asoc->active_key_id;
911
912 asoc->active_key_id = key_id;
913 if (sctp_auth_asoc_init_active_key(asoc, GFP_KERNEL)) {
914 asoc->active_key_id = active_key_id;
915 return -ENOMEM;
916 }
917 } else
918 ep->active_key_id = key_id;
919
920 return 0;
921 }
922
923 int sctp_auth_del_key_id(struct sctp_endpoint *ep,
924 struct sctp_association *asoc,
925 __u16 key_id)
926 {
927 struct sctp_shared_key *key;
928 struct list_head *sh_keys;
929 int found = 0;
930
931 /* The key identifier MUST NOT be the current active key
932 * The key identifier MUST correst to an existing key
933 */
934 if (asoc) {
935 if (!asoc->peer.auth_capable)
936 return -EACCES;
937 if (asoc->active_key_id == key_id)
938 return -EINVAL;
939
940 sh_keys = &asoc->endpoint_shared_keys;
941 } else {
942 if (!ep->auth_enable)
943 return -EACCES;
944 if (ep->active_key_id == key_id)
945 return -EINVAL;
946
947 sh_keys = &ep->endpoint_shared_keys;
948 }
949
950 key_for_each(key, sh_keys) {
951 if (key->key_id == key_id) {
952 found = 1;
953 break;
954 }
955 }
956
957 if (!found)
958 return -EINVAL;
959
960 /* Delete the shared key */
961 list_del_init(&key->key_list);
962 sctp_auth_shkey_release(key);
963
964 return 0;
965 }
966
967 int sctp_auth_deact_key_id(struct sctp_endpoint *ep,
968 struct sctp_association *asoc, __u16 key_id)
969 {
970 struct sctp_shared_key *key;
971 struct list_head *sh_keys;
972 int found = 0;
973
974 /* The key identifier MUST NOT be the current active key
975 * The key identifier MUST correst to an existing key
976 */
977 if (asoc) {
978 if (!asoc->peer.auth_capable)
979 return -EACCES;
980 if (asoc->active_key_id == key_id)
981 return -EINVAL;
982
983 sh_keys = &asoc->endpoint_shared_keys;
984 } else {
985 if (!ep->auth_enable)
986 return -EACCES;
987 if (ep->active_key_id == key_id)
988 return -EINVAL;
989
990 sh_keys = &ep->endpoint_shared_keys;
991 }
992
993 key_for_each(key, sh_keys) {
994 if (key->key_id == key_id) {
995 found = 1;
996 break;
997 }
998 }
999
1000 if (!found)
1001 return -EINVAL;
1002
1003 /* refcnt == 1 and !list_empty mean it's not being used anywhere
1004 * and deactivated will be set, so it's time to notify userland
1005 * that this shkey can be freed.
1006 */
1007 if (asoc && !list_empty(&key->key_list) &&
1008 refcount_read(&key->refcnt) == 1) {
1009 struct sctp_ulpevent *ev;
1010
1011 ev = sctp_ulpevent_make_authkey(asoc, key->key_id,
1012 SCTP_AUTH_FREE_KEY, GFP_KERNEL);
1013 if (ev)
1014 asoc->stream.si->enqueue_event(&asoc->ulpq, ev);
1015 }
1016
1017 key->deactivated = 1;
1018
1019 return 0;
1020 }
1021
1022 int sctp_auth_init(struct sctp_endpoint *ep, gfp_t gfp)
1023 {
1024 int err = -ENOMEM;
1025
1026 /* Allocate space for HMACS and CHUNKS authentication
1027 * variables. There are arrays that we encode directly
1028 * into parameters to make the rest of the operations easier.
1029 */
1030 if (!ep->auth_hmacs_list) {
1031 struct sctp_hmac_algo_param *auth_hmacs;
1032
1033 auth_hmacs = kzalloc(struct_size(auth_hmacs, hmac_ids,
1034 SCTP_AUTH_NUM_HMACS), gfp);
1035 if (!auth_hmacs)
1036 goto nomem;
1037 /* Initialize the HMACS parameter.
1038 * SCTP-AUTH: Section 3.3
1039 * Every endpoint supporting SCTP chunk authentication MUST
1040 * support the HMAC based on the SHA-1 algorithm.
1041 */
1042 auth_hmacs->param_hdr.type = SCTP_PARAM_HMAC_ALGO;
1043 auth_hmacs->param_hdr.length =
1044 htons(sizeof(struct sctp_paramhdr) + 2);
1045 auth_hmacs->hmac_ids[0] = htons(SCTP_AUTH_HMAC_ID_SHA1);
1046 ep->auth_hmacs_list = auth_hmacs;
1047 }
1048
1049 if (!ep->auth_chunk_list) {
1050 struct sctp_chunks_param *auth_chunks;
1051
1052 auth_chunks = kzalloc(sizeof(*auth_chunks) +
1053 SCTP_NUM_CHUNK_TYPES, gfp);
1054 if (!auth_chunks)
1055 goto nomem;
1056 /* Initialize the CHUNKS parameter */
1057 auth_chunks->param_hdr.type = SCTP_PARAM_CHUNKS;
1058 auth_chunks->param_hdr.length =
1059 htons(sizeof(struct sctp_paramhdr));
1060 ep->auth_chunk_list = auth_chunks;
1061 }
1062
1063 /* Allocate and initialize transorms arrays for supported
1064 * HMACs.
1065 */
1066 err = sctp_auth_init_hmacs(ep, gfp);
1067 if (err)
1068 goto nomem;
1069
1070 return 0;
1071
1072 nomem:
1073 /* Free all allocations */
1074 kfree(ep->auth_hmacs_list);
1075 kfree(ep->auth_chunk_list);
1076 ep->auth_hmacs_list = NULL;
1077 ep->auth_chunk_list = NULL;
1078 return err;
1079 }
1080
1081 void sctp_auth_free(struct sctp_endpoint *ep)
1082 {
1083 kfree(ep->auth_hmacs_list);
1084 kfree(ep->auth_chunk_list);
1085 ep->auth_hmacs_list = NULL;
1086 ep->auth_chunk_list = NULL;
1087 sctp_auth_destroy_hmacs(ep->auth_hmacs);
1088 ep->auth_hmacs = NULL;
1089 }
1090
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