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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 <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}
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 (refcount_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 refcount_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 refcount_set(&new->refcnt, 1);
105 new->key_id = key_id;
106
107 return new;
108}
109
110/* Free the shared key structure */
111static void sctp_auth_shkey_destroy(struct sctp_shared_key *sh_key)
112{
113 BUG_ON(!list_empty(&sh_key->key_list));
114 sctp_auth_key_put(sh_key->key);
115 sh_key->key = NULL;
116 kfree(sh_key);
117}
118
119void sctp_auth_shkey_release(struct sctp_shared_key *sh_key)
120{
121 if (refcount_dec_and_test(&sh_key->refcnt))
122 sctp_auth_shkey_destroy(sh_key);
123}
124
125void sctp_auth_shkey_hold(struct sctp_shared_key *sh_key)
126{
127 refcount_inc(&sh_key->refcnt);
128}
129
130/* Destroy the entire key list. This is done during the
131 * associon and endpoint free process.
132 */
133void sctp_auth_destroy_keys(struct list_head *keys)
134{
135 struct sctp_shared_key *ep_key;
136 struct sctp_shared_key *tmp;
137
138 if (list_empty(keys))
139 return;
140
141 key_for_each_safe(ep_key, tmp, keys) {
142 list_del_init(&ep_key->key_list);
143 sctp_auth_shkey_release(ep_key);
144 }
145}
146
147/* Compare two byte vectors as numbers. Return values
148 * are:
149 * 0 - vectors are equal
150 * < 0 - vector 1 is smaller than vector2
151 * > 0 - vector 1 is greater than vector2
152 *
153 * Algorithm is:
154 * This is performed by selecting the numerically smaller key vector...
155 * If the key vectors are equal as numbers but differ in length ...
156 * the shorter vector is considered smaller
157 *
158 * Examples (with small values):
159 * 000123456789 > 123456789 (first number is longer)
160 * 000123456789 < 234567891 (second number is larger numerically)
161 * 123456789 > 2345678 (first number is both larger & longer)
162 */
163static int sctp_auth_compare_vectors(struct sctp_auth_bytes *vector1,
164 struct sctp_auth_bytes *vector2)
165{
166 int diff;
167 int i;
168 const __u8 *longer;
169
170 diff = vector1->len - vector2->len;
171 if (diff) {
172 longer = (diff > 0) ? vector1->data : vector2->data;
173
174 /* Check to see if the longer number is
175 * lead-zero padded. If it is not, it
176 * is automatically larger numerically.
177 */
178 for (i = 0; i < abs(diff); i++) {
179 if (longer[i] != 0)
180 return diff;
181 }
182 }
183
184 /* lengths are the same, compare numbers */
185 return memcmp(vector1->data, vector2->data, vector1->len);
186}
187
188/*
189 * Create a key vector as described in SCTP-AUTH, Section 6.1
190 * The RANDOM parameter, the CHUNKS parameter and the HMAC-ALGO
191 * parameter sent by each endpoint are concatenated as byte vectors.
192 * These parameters include the parameter type, parameter length, and
193 * the parameter value, but padding is omitted; all padding MUST be
194 * removed from this concatenation before proceeding with further
195 * computation of keys. Parameters which were not sent are simply
196 * omitted from the concatenation process. The resulting two vectors
197 * are called the two key vectors.
198 */
199static struct sctp_auth_bytes *sctp_auth_make_key_vector(
200 struct sctp_random_param *random,
201 struct sctp_chunks_param *chunks,
202 struct sctp_hmac_algo_param *hmacs,
203 gfp_t gfp)
204{
205 struct sctp_auth_bytes *new;
206 __u32 len;
207 __u32 offset = 0;
208 __u16 random_len, hmacs_len, chunks_len = 0;
209
210 random_len = ntohs(random->param_hdr.length);
211 hmacs_len = ntohs(hmacs->param_hdr.length);
212 if (chunks)
213 chunks_len = ntohs(chunks->param_hdr.length);
214
215 len = random_len + hmacs_len + chunks_len;
216
217 new = sctp_auth_create_key(len, gfp);
218 if (!new)
219 return NULL;
220
221 memcpy(new->data, random, random_len);
222 offset += random_len;
223
224 if (chunks) {
225 memcpy(new->data + offset, chunks, chunks_len);
226 offset += chunks_len;
227 }
228
229 memcpy(new->data + offset, hmacs, hmacs_len);
230
231 return new;
232}
233
234
235/* Make a key vector based on our local parameters */
236static struct sctp_auth_bytes *sctp_auth_make_local_vector(
237 const struct sctp_association *asoc,
238 gfp_t gfp)
239{
240 return sctp_auth_make_key_vector(
241 (struct sctp_random_param *)asoc->c.auth_random,
242 (struct sctp_chunks_param *)asoc->c.auth_chunks,
243 (struct sctp_hmac_algo_param *)asoc->c.auth_hmacs, gfp);
244}
245
246/* Make a key vector based on peer's parameters */
247static struct sctp_auth_bytes *sctp_auth_make_peer_vector(
248 const struct sctp_association *asoc,
249 gfp_t gfp)
250{
251 return sctp_auth_make_key_vector(asoc->peer.peer_random,
252 asoc->peer.peer_chunks,
253 asoc->peer.peer_hmacs,
254 gfp);
255}
256
257
258/* Set the value of the association shared key base on the parameters
259 * given. The algorithm is:
260 * From the endpoint pair shared keys and the key vectors the
261 * association shared keys are computed. This is performed by selecting
262 * the numerically smaller key vector and concatenating it to the
263 * endpoint pair shared key, and then concatenating the numerically
264 * larger key vector to that. The result of the concatenation is the
265 * association shared key.
266 */
267static struct sctp_auth_bytes *sctp_auth_asoc_set_secret(
268 struct sctp_shared_key *ep_key,
269 struct sctp_auth_bytes *first_vector,
270 struct sctp_auth_bytes *last_vector,
271 gfp_t gfp)
272{
273 struct sctp_auth_bytes *secret;
274 __u32 offset = 0;
275 __u32 auth_len;
276
277 auth_len = first_vector->len + last_vector->len;
278 if (ep_key->key)
279 auth_len += ep_key->key->len;
280
281 secret = sctp_auth_create_key(auth_len, gfp);
282 if (!secret)
283 return NULL;
284
285 if (ep_key->key) {
286 memcpy(secret->data, ep_key->key->data, ep_key->key->len);
287 offset += ep_key->key->len;
288 }
289
290 memcpy(secret->data + offset, first_vector->data, first_vector->len);
291 offset += first_vector->len;
292
293 memcpy(secret->data + offset, last_vector->data, last_vector->len);
294
295 return secret;
296}
297
298/* Create an association shared key. Follow the algorithm
299 * described in SCTP-AUTH, Section 6.1
300 */
301static struct sctp_auth_bytes *sctp_auth_asoc_create_secret(
302 const struct sctp_association *asoc,
303 struct sctp_shared_key *ep_key,
304 gfp_t gfp)
305{
306 struct sctp_auth_bytes *local_key_vector;
307 struct sctp_auth_bytes *peer_key_vector;
308 struct sctp_auth_bytes *first_vector,
309 *last_vector;
310 struct sctp_auth_bytes *secret = NULL;
311 int cmp;
312
313
314 /* Now we need to build the key vectors
315 * SCTP-AUTH , Section 6.1
316 * The RANDOM parameter, the CHUNKS parameter and the HMAC-ALGO
317 * parameter sent by each endpoint are concatenated as byte vectors.
318 * These parameters include the parameter type, parameter length, and
319 * the parameter value, but padding is omitted; all padding MUST be
320 * removed from this concatenation before proceeding with further
321 * computation of keys. Parameters which were not sent are simply
322 * omitted from the concatenation process. The resulting two vectors
323 * are called the two key vectors.
324 */
325
326 local_key_vector = sctp_auth_make_local_vector(asoc, gfp);
327 peer_key_vector = sctp_auth_make_peer_vector(asoc, gfp);
328
329 if (!peer_key_vector || !local_key_vector)
330 goto out;
331
332 /* Figure out the order in which the key_vectors will be
333 * added to the endpoint shared key.
334 * SCTP-AUTH, Section 6.1:
335 * This is performed by selecting the numerically smaller key
336 * vector and concatenating it to the endpoint pair shared
337 * key, and then concatenating the numerically larger key
338 * vector to that. If the key vectors are equal as numbers
339 * but differ in length, then the concatenation order is the
340 * endpoint shared key, followed by the shorter key vector,
341 * followed by the longer key vector. Otherwise, the key
342 * vectors are identical, and may be concatenated to the
343 * endpoint pair key in any order.
344 */
345 cmp = sctp_auth_compare_vectors(local_key_vector,
346 peer_key_vector);
347 if (cmp < 0) {
348 first_vector = local_key_vector;
349 last_vector = peer_key_vector;
350 } else {
351 first_vector = peer_key_vector;
352 last_vector = local_key_vector;
353 }
354
355 secret = sctp_auth_asoc_set_secret(ep_key, first_vector, last_vector,
356 gfp);
357out:
358 sctp_auth_key_put(local_key_vector);
359 sctp_auth_key_put(peer_key_vector);
360
361 return secret;
362}
363
364/*
365 * Populate the association overlay list with the list
366 * from the endpoint.
367 */
368int sctp_auth_asoc_copy_shkeys(const struct sctp_endpoint *ep,
369 struct sctp_association *asoc,
370 gfp_t gfp)
371{
372 struct sctp_shared_key *sh_key;
373 struct sctp_shared_key *new;
374
375 BUG_ON(!list_empty(&asoc->endpoint_shared_keys));
376
377 key_for_each(sh_key, &ep->endpoint_shared_keys) {
378 new = sctp_auth_shkey_create(sh_key->key_id, gfp);
379 if (!new)
380 goto nomem;
381
382 new->key = sh_key->key;
383 sctp_auth_key_hold(new->key);
384 list_add(&new->key_list, &asoc->endpoint_shared_keys);
385 }
386
387 return 0;
388
389nomem:
390 sctp_auth_destroy_keys(&asoc->endpoint_shared_keys);
391 return -ENOMEM;
392}
393
394
395/* Public interface to create the association shared key.
396 * See code above for the algorithm.
397 */
398int sctp_auth_asoc_init_active_key(struct sctp_association *asoc, gfp_t gfp)
399{
400 struct sctp_auth_bytes *secret;
401 struct sctp_shared_key *ep_key;
402 struct sctp_chunk *chunk;
403
404 /* If we don't support AUTH, or peer is not capable
405 * we don't need to do anything.
406 */
407 if (!asoc->ep->auth_enable || !asoc->peer.auth_capable)
408 return 0;
409
410 /* If the key_id is non-zero and we couldn't find an
411 * endpoint pair shared key, we can't compute the
412 * secret.
413 * For key_id 0, endpoint pair shared key is a NULL key.
414 */
415 ep_key = sctp_auth_get_shkey(asoc, asoc->active_key_id);
416 BUG_ON(!ep_key);
417
418 secret = sctp_auth_asoc_create_secret(asoc, ep_key, gfp);
419 if (!secret)
420 return -ENOMEM;
421
422 sctp_auth_key_put(asoc->asoc_shared_key);
423 asoc->asoc_shared_key = secret;
424 asoc->shkey = ep_key;
425
426 /* Update send queue in case any chunk already in there now
427 * needs authenticating
428 */
429 list_for_each_entry(chunk, &asoc->outqueue.out_chunk_list, list) {
430 if (sctp_auth_send_cid(chunk->chunk_hdr->type, asoc)) {
431 chunk->auth = 1;
432 if (!chunk->shkey) {
433 chunk->shkey = asoc->shkey;
434 sctp_auth_shkey_hold(chunk->shkey);
435 }
436 }
437 }
438
439 return 0;
440}
441
442
443/* Find the endpoint pair shared key based on the key_id */
444struct sctp_shared_key *sctp_auth_get_shkey(
445 const struct sctp_association *asoc,
446 __u16 key_id)
447{
448 struct sctp_shared_key *key;
449
450 /* First search associations set of endpoint pair shared keys */
451 key_for_each(key, &asoc->endpoint_shared_keys) {
452 if (key->key_id == key_id) {
453 if (!key->deactivated)
454 return key;
455 break;
456 }
457 }
458
459 return NULL;
460}
461
462/*
463 * Initialize all the possible digest transforms that we can use. Right now
464 * now, the supported digests are SHA1 and SHA256. We do this here once
465 * because of the restrictiong that transforms may only be allocated in
466 * user context. This forces us to pre-allocated all possible transforms
467 * at the endpoint init time.
468 */
469int sctp_auth_init_hmacs(struct sctp_endpoint *ep, gfp_t gfp)
470{
471 struct crypto_shash *tfm = NULL;
472 __u16 id;
473
474 /* If AUTH extension is disabled, we are done */
475 if (!ep->auth_enable) {
476 ep->auth_hmacs = NULL;
477 return 0;
478 }
479
480 /* If the transforms are already allocated, we are done */
481 if (ep->auth_hmacs)
482 return 0;
483
484 /* Allocated the array of pointers to transorms */
485 ep->auth_hmacs = kzalloc(sizeof(struct crypto_shash *) *
486 SCTP_AUTH_NUM_HMACS, gfp);
487 if (!ep->auth_hmacs)
488 return -ENOMEM;
489
490 for (id = 0; id < SCTP_AUTH_NUM_HMACS; id++) {
491
492 /* See is we support the id. Supported IDs have name and
493 * length fields set, so that we can allocated and use
494 * them. We can safely just check for name, for without the
495 * name, we can't allocate the TFM.
496 */
497 if (!sctp_hmac_list[id].hmac_name)
498 continue;
499
500 /* If this TFM has been allocated, we are all set */
501 if (ep->auth_hmacs[id])
502 continue;
503
504 /* Allocate the ID */
505 tfm = crypto_alloc_shash(sctp_hmac_list[id].hmac_name, 0, 0);
506 if (IS_ERR(tfm))
507 goto out_err;
508
509 ep->auth_hmacs[id] = tfm;
510 }
511
512 return 0;
513
514out_err:
515 /* Clean up any successful allocations */
516 sctp_auth_destroy_hmacs(ep->auth_hmacs);
517 return -ENOMEM;
518}
519
520/* Destroy the hmac tfm array */
521void sctp_auth_destroy_hmacs(struct crypto_shash *auth_hmacs[])
522{
523 int i;
524
525 if (!auth_hmacs)
526 return;
527
528 for (i = 0; i < SCTP_AUTH_NUM_HMACS; i++) {
529 crypto_free_shash(auth_hmacs[i]);
530 }
531 kfree(auth_hmacs);
532}
533
534
535struct sctp_hmac *sctp_auth_get_hmac(__u16 hmac_id)
536{
537 return &sctp_hmac_list[hmac_id];
538}
539
540/* Get an hmac description information that we can use to build
541 * the AUTH chunk
542 */
543struct sctp_hmac *sctp_auth_asoc_get_hmac(const struct sctp_association *asoc)
544{
545 struct sctp_hmac_algo_param *hmacs;
546 __u16 n_elt;
547 __u16 id = 0;
548 int i;
549
550 /* If we have a default entry, use it */
551 if (asoc->default_hmac_id)
552 return &sctp_hmac_list[asoc->default_hmac_id];
553
554 /* Since we do not have a default entry, find the first entry
555 * we support and return that. Do not cache that id.
556 */
557 hmacs = asoc->peer.peer_hmacs;
558 if (!hmacs)
559 return NULL;
560
561 n_elt = (ntohs(hmacs->param_hdr.length) -
562 sizeof(struct sctp_paramhdr)) >> 1;
563 for (i = 0; i < n_elt; i++) {
564 id = ntohs(hmacs->hmac_ids[i]);
565
566 /* Check the id is in the supported range. And
567 * see if we support the id. Supported IDs have name and
568 * length fields set, so that we can allocate and use
569 * them. We can safely just check for name, for without the
570 * name, we can't allocate the TFM.
571 */
572 if (id > SCTP_AUTH_HMAC_ID_MAX ||
573 !sctp_hmac_list[id].hmac_name) {
574 id = 0;
575 continue;
576 }
577
578 break;
579 }
580
581 if (id == 0)
582 return NULL;
583
584 return &sctp_hmac_list[id];
585}
586
587static int __sctp_auth_find_hmacid(__be16 *hmacs, int n_elts, __be16 hmac_id)
588{
589 int found = 0;
590 int i;
591
592 for (i = 0; i < n_elts; i++) {
593 if (hmac_id == hmacs[i]) {
594 found = 1;
595 break;
596 }
597 }
598
599 return found;
600}
601
602/* See if the HMAC_ID is one that we claim as supported */
603int sctp_auth_asoc_verify_hmac_id(const struct sctp_association *asoc,
604 __be16 hmac_id)
605{
606 struct sctp_hmac_algo_param *hmacs;
607 __u16 n_elt;
608
609 if (!asoc)
610 return 0;
611
612 hmacs = (struct sctp_hmac_algo_param *)asoc->c.auth_hmacs;
613 n_elt = (ntohs(hmacs->param_hdr.length) -
614 sizeof(struct sctp_paramhdr)) >> 1;
615
616 return __sctp_auth_find_hmacid(hmacs->hmac_ids, n_elt, hmac_id);
617}
618
619
620/* Cache the default HMAC id. This to follow this text from SCTP-AUTH:
621 * Section 6.1:
622 * The receiver of a HMAC-ALGO parameter SHOULD use the first listed
623 * algorithm it supports.
624 */
625void sctp_auth_asoc_set_default_hmac(struct sctp_association *asoc,
626 struct sctp_hmac_algo_param *hmacs)
627{
628 struct sctp_endpoint *ep;
629 __u16 id;
630 int i;
631 int n_params;
632
633 /* if the default id is already set, use it */
634 if (asoc->default_hmac_id)
635 return;
636
637 n_params = (ntohs(hmacs->param_hdr.length) -
638 sizeof(struct sctp_paramhdr)) >> 1;
639 ep = asoc->ep;
640 for (i = 0; i < n_params; i++) {
641 id = ntohs(hmacs->hmac_ids[i]);
642
643 /* Check the id is in the supported range */
644 if (id > SCTP_AUTH_HMAC_ID_MAX)
645 continue;
646
647 /* If this TFM has been allocated, use this id */
648 if (ep->auth_hmacs[id]) {
649 asoc->default_hmac_id = id;
650 break;
651 }
652 }
653}
654
655
656/* Check to see if the given chunk is supposed to be authenticated */
657static int __sctp_auth_cid(enum sctp_cid chunk, struct sctp_chunks_param *param)
658{
659 unsigned short len;
660 int found = 0;
661 int i;
662
663 if (!param || param->param_hdr.length == 0)
664 return 0;
665
666 len = ntohs(param->param_hdr.length) - sizeof(struct sctp_paramhdr);
667
668 /* SCTP-AUTH, Section 3.2
669 * The chunk types for INIT, INIT-ACK, SHUTDOWN-COMPLETE and AUTH
670 * chunks MUST NOT be listed in the CHUNKS parameter. However, if
671 * a CHUNKS parameter is received then the types for INIT, INIT-ACK,
672 * SHUTDOWN-COMPLETE and AUTH chunks MUST be ignored.
673 */
674 for (i = 0; !found && i < len; i++) {
675 switch (param->chunks[i]) {
676 case SCTP_CID_INIT:
677 case SCTP_CID_INIT_ACK:
678 case SCTP_CID_SHUTDOWN_COMPLETE:
679 case SCTP_CID_AUTH:
680 break;
681
682 default:
683 if (param->chunks[i] == chunk)
684 found = 1;
685 break;
686 }
687 }
688
689 return found;
690}
691
692/* Check if peer requested that this chunk is authenticated */
693int sctp_auth_send_cid(enum sctp_cid chunk, const struct sctp_association *asoc)
694{
695 if (!asoc)
696 return 0;
697
698 if (!asoc->ep->auth_enable || !asoc->peer.auth_capable)
699 return 0;
700
701 return __sctp_auth_cid(chunk, asoc->peer.peer_chunks);
702}
703
704/* Check if we requested that peer authenticate this chunk. */
705int sctp_auth_recv_cid(enum sctp_cid chunk, const struct sctp_association *asoc)
706{
707 if (!asoc)
708 return 0;
709
710 if (!asoc->ep->auth_enable)
711 return 0;
712
713 return __sctp_auth_cid(chunk,
714 (struct sctp_chunks_param *)asoc->c.auth_chunks);
715}
716
717/* SCTP-AUTH: Section 6.2:
718 * The sender MUST calculate the MAC as described in RFC2104 [2] using
719 * the hash function H as described by the MAC Identifier and the shared
720 * association key K based on the endpoint pair shared key described by
721 * the shared key identifier. The 'data' used for the computation of
722 * the AUTH-chunk is given by the AUTH chunk with its HMAC field set to
723 * zero (as shown in Figure 6) followed by all chunks that are placed
724 * after the AUTH chunk in the SCTP packet.
725 */
726void sctp_auth_calculate_hmac(const struct sctp_association *asoc,
727 struct sk_buff *skb, struct sctp_auth_chunk *auth,
728 struct sctp_shared_key *ep_key, gfp_t gfp)
729{
730 struct sctp_auth_bytes *asoc_key;
731 struct crypto_shash *tfm;
732 __u16 key_id, hmac_id;
733 unsigned char *end;
734 int free_key = 0;
735 __u8 *digest;
736
737 /* Extract the info we need:
738 * - hmac id
739 * - key id
740 */
741 key_id = ntohs(auth->auth_hdr.shkey_id);
742 hmac_id = ntohs(auth->auth_hdr.hmac_id);
743
744 if (key_id == asoc->active_key_id)
745 asoc_key = asoc->asoc_shared_key;
746 else {
747 /* ep_key can't be NULL here */
748 asoc_key = sctp_auth_asoc_create_secret(asoc, ep_key, gfp);
749 if (!asoc_key)
750 return;
751
752 free_key = 1;
753 }
754
755 /* set up scatter list */
756 end = skb_tail_pointer(skb);
757
758 tfm = asoc->ep->auth_hmacs[hmac_id];
759
760 digest = auth->auth_hdr.hmac;
761 if (crypto_shash_setkey(tfm, &asoc_key->data[0], asoc_key->len))
762 goto free;
763
764 {
765 SHASH_DESC_ON_STACK(desc, tfm);
766
767 desc->tfm = tfm;
768 desc->flags = 0;
769 crypto_shash_digest(desc, (u8 *)auth,
770 end - (unsigned char *)auth, digest);
771 shash_desc_zero(desc);
772 }
773
774free:
775 if (free_key)
776 sctp_auth_key_put(asoc_key);
777}
778
779/* API Helpers */
780
781/* Add a chunk to the endpoint authenticated chunk list */
782int sctp_auth_ep_add_chunkid(struct sctp_endpoint *ep, __u8 chunk_id)
783{
784 struct sctp_chunks_param *p = ep->auth_chunk_list;
785 __u16 nchunks;
786 __u16 param_len;
787
788 /* If this chunk is already specified, we are done */
789 if (__sctp_auth_cid(chunk_id, p))
790 return 0;
791
792 /* Check if we can add this chunk to the array */
793 param_len = ntohs(p->param_hdr.length);
794 nchunks = param_len - sizeof(struct sctp_paramhdr);
795 if (nchunks == SCTP_NUM_CHUNK_TYPES)
796 return -EINVAL;
797
798 p->chunks[nchunks] = chunk_id;
799 p->param_hdr.length = htons(param_len + 1);
800 return 0;
801}
802
803/* Add hmac identifires to the endpoint list of supported hmac ids */
804int sctp_auth_ep_set_hmacs(struct sctp_endpoint *ep,
805 struct sctp_hmacalgo *hmacs)
806{
807 int has_sha1 = 0;
808 __u16 id;
809 int i;
810
811 /* Scan the list looking for unsupported id. Also make sure that
812 * SHA1 is specified.
813 */
814 for (i = 0; i < hmacs->shmac_num_idents; i++) {
815 id = hmacs->shmac_idents[i];
816
817 if (id > SCTP_AUTH_HMAC_ID_MAX)
818 return -EOPNOTSUPP;
819
820 if (SCTP_AUTH_HMAC_ID_SHA1 == id)
821 has_sha1 = 1;
822
823 if (!sctp_hmac_list[id].hmac_name)
824 return -EOPNOTSUPP;
825 }
826
827 if (!has_sha1)
828 return -EINVAL;
829
830 for (i = 0; i < hmacs->shmac_num_idents; i++)
831 ep->auth_hmacs_list->hmac_ids[i] =
832 htons(hmacs->shmac_idents[i]);
833 ep->auth_hmacs_list->param_hdr.length =
834 htons(sizeof(struct sctp_paramhdr) +
835 hmacs->shmac_num_idents * sizeof(__u16));
836 return 0;
837}
838
839/* Set a new shared key on either endpoint or association. If the
840 * the key with a same ID already exists, replace the key (remove the
841 * old key and add a new one).
842 */
843int sctp_auth_set_key(struct sctp_endpoint *ep,
844 struct sctp_association *asoc,
845 struct sctp_authkey *auth_key)
846{
847 struct sctp_shared_key *cur_key, *shkey;
848 struct sctp_auth_bytes *key;
849 struct list_head *sh_keys;
850 int replace = 0;
851
852 /* Try to find the given key id to see if
853 * we are doing a replace, or adding a new key
854 */
855 if (asoc)
856 sh_keys = &asoc->endpoint_shared_keys;
857 else
858 sh_keys = &ep->endpoint_shared_keys;
859
860 key_for_each(shkey, sh_keys) {
861 if (shkey->key_id == auth_key->sca_keynumber) {
862 replace = 1;
863 break;
864 }
865 }
866
867 cur_key = sctp_auth_shkey_create(auth_key->sca_keynumber, GFP_KERNEL);
868 if (!cur_key)
869 return -ENOMEM;
870
871 /* Create a new key data based on the info passed in */
872 key = sctp_auth_create_key(auth_key->sca_keylength, GFP_KERNEL);
873 if (!key) {
874 kfree(cur_key);
875 return -ENOMEM;
876 }
877
878 memcpy(key->data, &auth_key->sca_key[0], auth_key->sca_keylength);
879 cur_key->key = key;
880
881 if (replace) {
882 list_del_init(&shkey->key_list);
883 sctp_auth_shkey_release(shkey);
884 }
885 list_add(&cur_key->key_list, sh_keys);
886
887 return 0;
888}
889
890int sctp_auth_set_active_key(struct sctp_endpoint *ep,
891 struct sctp_association *asoc,
892 __u16 key_id)
893{
894 struct sctp_shared_key *key;
895 struct list_head *sh_keys;
896 int found = 0;
897
898 /* The key identifier MUST correst to an existing key */
899 if (asoc)
900 sh_keys = &asoc->endpoint_shared_keys;
901 else
902 sh_keys = &ep->endpoint_shared_keys;
903
904 key_for_each(key, sh_keys) {
905 if (key->key_id == key_id) {
906 found = 1;
907 break;
908 }
909 }
910
911 if (!found || key->deactivated)
912 return -EINVAL;
913
914 if (asoc) {
915 asoc->active_key_id = key_id;
916 sctp_auth_asoc_init_active_key(asoc, GFP_KERNEL);
917 } else
918 ep->active_key_id = key_id;
919
920 return 0;
921}
922
923int 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->active_key_id == key_id)
936 return -EINVAL;
937
938 sh_keys = &asoc->endpoint_shared_keys;
939 } else {
940 if (ep->active_key_id == key_id)
941 return -EINVAL;
942
943 sh_keys = &ep->endpoint_shared_keys;
944 }
945
946 key_for_each(key, sh_keys) {
947 if (key->key_id == key_id) {
948 found = 1;
949 break;
950 }
951 }
952
953 if (!found)
954 return -EINVAL;
955
956 /* Delete the shared key */
957 list_del_init(&key->key_list);
958 sctp_auth_shkey_release(key);
959
960 return 0;
961}
962
963int sctp_auth_deact_key_id(struct sctp_endpoint *ep,
964 struct sctp_association *asoc, __u16 key_id)
965{
966 struct sctp_shared_key *key;
967 struct list_head *sh_keys;
968 int found = 0;
969
970 /* The key identifier MUST NOT be the current active key
971 * The key identifier MUST correst to an existing key
972 */
973 if (asoc) {
974 if (asoc->active_key_id == key_id)
975 return -EINVAL;
976
977 sh_keys = &asoc->endpoint_shared_keys;
978 } else {
979 if (ep->active_key_id == key_id)
980 return -EINVAL;
981
982 sh_keys = &ep->endpoint_shared_keys;
983 }
984
985 key_for_each(key, sh_keys) {
986 if (key->key_id == key_id) {
987 found = 1;
988 break;
989 }
990 }
991
992 if (!found)
993 return -EINVAL;
994
995 /* refcnt == 1 and !list_empty mean it's not being used anywhere
996 * and deactivated will be set, so it's time to notify userland
997 * that this shkey can be freed.
998 */
999 if (asoc && !list_empty(&key->key_list) &&
1000 refcount_read(&key->refcnt) == 1) {
1001 struct sctp_ulpevent *ev;
1002
1003 ev = sctp_ulpevent_make_authkey(asoc, key->key_id,
1004 SCTP_AUTH_FREE_KEY, GFP_KERNEL);
1005 if (ev)
1006 asoc->stream.si->enqueue_event(&asoc->ulpq, ev);
1007 }
1008
1009 key->deactivated = 1;
1010
1011 return 0;
1012}