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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 <[email protected]>
10 *
11 * Written or modified by:
12 * Vlad Yasevich <[email protected]>
13 */
14
15#include <crypto/sha1.h>
16#include <crypto/sha2.h>
17#include <linux/slab.h>
18#include <linux/types.h>
19#include <net/sctp/sctp.h>
20#include <net/sctp/auth.h>
21
22static const 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_len = SHA1_DIGEST_SIZE,
30 },
31 {
32 /* id 2 is reserved as well */
33 .hmac_id = SCTP_AUTH_HMAC_ID_RESERVED_2,
34 },
35 {
36 .hmac_id = SCTP_AUTH_HMAC_ID_SHA256,
37 .hmac_len = SHA256_DIGEST_SIZE,
38 }
39};
40
41static bool sctp_hmac_supported(__u16 hmac_id)
42{
43 return hmac_id < ARRAY_SIZE(sctp_hmac_list) &&
44 sctp_hmac_list[hmac_id].hmac_len != 0;
45}
46
47void sctp_auth_key_put(struct sctp_auth_bytes *key)
48{
49 if (!key)
50 return;
51
52 if (refcount_dec_and_test(&key->refcnt)) {
53 kfree_sensitive(key);
54 SCTP_DBG_OBJCNT_DEC(keys);
55 }
56}
57
58/* Create a new key structure of a given length */
59static struct sctp_auth_bytes *sctp_auth_create_key(__u32 key_len, gfp_t gfp)
60{
61 struct sctp_auth_bytes *key;
62
63 /* Verify that we are not going to overflow INT_MAX */
64 if (key_len > (INT_MAX - sizeof(struct sctp_auth_bytes)))
65 return NULL;
66
67 /* Allocate the shared key */
68 key = kmalloc(sizeof(struct sctp_auth_bytes) + key_len, gfp);
69 if (!key)
70 return NULL;
71
72 key->len = key_len;
73 refcount_set(&key->refcnt, 1);
74 SCTP_DBG_OBJCNT_INC(keys);
75
76 return key;
77}
78
79/* Create a new shared key container with a give key id */
80struct sctp_shared_key *sctp_auth_shkey_create(__u16 key_id, gfp_t gfp)
81{
82 struct sctp_shared_key *new;
83
84 /* Allocate the shared key container */
85 new = kzalloc_obj(struct sctp_shared_key, gfp);
86 if (!new)
87 return NULL;
88
89 INIT_LIST_HEAD(&new->key_list);
90 refcount_set(&new->refcnt, 1);
91 new->key_id = key_id;
92
93 return new;
94}
95
96/* Free the shared key structure */
97static void sctp_auth_shkey_destroy(struct sctp_shared_key *sh_key)
98{
99 BUG_ON(!list_empty(&sh_key->key_list));
100 sctp_auth_key_put(sh_key->key);
101 sh_key->key = NULL;
102 kfree(sh_key);
103}
104
105void sctp_auth_shkey_release(struct sctp_shared_key *sh_key)
106{
107 if (refcount_dec_and_test(&sh_key->refcnt))
108 sctp_auth_shkey_destroy(sh_key);
109}
110
111void sctp_auth_shkey_hold(struct sctp_shared_key *sh_key)
112{
113 refcount_inc(&sh_key->refcnt);
114}
115
116/* Destroy the entire key list. This is done during the
117 * associon and endpoint free process.
118 */
119void sctp_auth_destroy_keys(struct list_head *keys)
120{
121 struct sctp_shared_key *ep_key;
122 struct sctp_shared_key *tmp;
123
124 if (list_empty(keys))
125 return;
126
127 key_for_each_safe(ep_key, tmp, keys) {
128 list_del_init(&ep_key->key_list);
129 sctp_auth_shkey_release(ep_key);
130 }
131}
132
133/* Compare two byte vectors as numbers. Return values
134 * are:
135 * 0 - vectors are equal
136 * < 0 - vector 1 is smaller than vector2
137 * > 0 - vector 1 is greater than vector2
138 *
139 * Algorithm is:
140 * This is performed by selecting the numerically smaller key vector...
141 * If the key vectors are equal as numbers but differ in length ...
142 * the shorter vector is considered smaller
143 *
144 * Examples (with small values):
145 * 000123456789 > 123456789 (first number is longer)
146 * 000123456789 < 234567891 (second number is larger numerically)
147 * 123456789 > 2345678 (first number is both larger & longer)
148 */
149static int sctp_auth_compare_vectors(struct sctp_auth_bytes *vector1,
150 struct sctp_auth_bytes *vector2)
151{
152 int diff;
153 int i;
154 const __u8 *longer;
155
156 diff = vector1->len - vector2->len;
157 if (diff) {
158 longer = (diff > 0) ? vector1->data : vector2->data;
159
160 /* Check to see if the longer number is
161 * lead-zero padded. If it is not, it
162 * is automatically larger numerically.
163 */
164 for (i = 0; i < abs(diff); i++) {
165 if (longer[i] != 0)
166 return diff;
167 }
168 }
169
170 /* lengths are the same, compare numbers */
171 return memcmp(vector1->data, vector2->data, vector1->len);
172}
173
174/*
175 * Create a key vector as described in SCTP-AUTH, Section 6.1
176 * The RANDOM parameter, the CHUNKS parameter and the HMAC-ALGO
177 * parameter sent by each endpoint are concatenated as byte vectors.
178 * These parameters include the parameter type, parameter length, and
179 * the parameter value, but padding is omitted; all padding MUST be
180 * removed from this concatenation before proceeding with further
181 * computation of keys. Parameters which were not sent are simply
182 * omitted from the concatenation process. The resulting two vectors
183 * are called the two key vectors.
184 */
185static struct sctp_auth_bytes *sctp_auth_make_key_vector(
186 struct sctp_random_param *random,
187 struct sctp_chunks_param *chunks,
188 struct sctp_hmac_algo_param *hmacs,
189 gfp_t gfp)
190{
191 struct sctp_auth_bytes *new;
192 __u32 len;
193 __u32 offset = 0;
194 __u16 random_len, hmacs_len, chunks_len = 0;
195
196 random_len = ntohs(random->param_hdr.length);
197 hmacs_len = ntohs(hmacs->param_hdr.length);
198 if (chunks)
199 chunks_len = ntohs(chunks->param_hdr.length);
200
201 len = random_len + hmacs_len + chunks_len;
202
203 new = sctp_auth_create_key(len, gfp);
204 if (!new)
205 return NULL;
206
207 memcpy(new->data, random, random_len);
208 offset += random_len;
209
210 if (chunks) {
211 memcpy(new->data + offset, chunks, chunks_len);
212 offset += chunks_len;
213 }
214
215 memcpy(new->data + offset, hmacs, hmacs_len);
216
217 return new;
218}
219
220
221/* Make a key vector based on our local parameters */
222static struct sctp_auth_bytes *sctp_auth_make_local_vector(
223 const struct sctp_association *asoc,
224 gfp_t gfp)
225{
226 return sctp_auth_make_key_vector(
227 (struct sctp_random_param *)asoc->c.auth_random,
228 (struct sctp_chunks_param *)asoc->c.auth_chunks,
229 (struct sctp_hmac_algo_param *)asoc->c.auth_hmacs, gfp);
230}
231
232/* Make a key vector based on peer's parameters */
233static struct sctp_auth_bytes *sctp_auth_make_peer_vector(
234 const struct sctp_association *asoc,
235 gfp_t gfp)
236{
237 return sctp_auth_make_key_vector(asoc->peer.peer_random,
238 asoc->peer.peer_chunks,
239 asoc->peer.peer_hmacs,
240 gfp);
241}
242
243
244/* Set the value of the association shared key base on the parameters
245 * given. The algorithm is:
246 * From the endpoint pair shared keys and the key vectors the
247 * association shared keys are computed. This is performed by selecting
248 * the numerically smaller key vector and concatenating it to the
249 * endpoint pair shared key, and then concatenating the numerically
250 * larger key vector to that. The result of the concatenation is the
251 * association shared key.
252 */
253static struct sctp_auth_bytes *sctp_auth_asoc_set_secret(
254 struct sctp_shared_key *ep_key,
255 struct sctp_auth_bytes *first_vector,
256 struct sctp_auth_bytes *last_vector,
257 gfp_t gfp)
258{
259 struct sctp_auth_bytes *secret;
260 __u32 offset = 0;
261 __u32 auth_len;
262
263 auth_len = first_vector->len + last_vector->len;
264 if (ep_key->key)
265 auth_len += ep_key->key->len;
266
267 secret = sctp_auth_create_key(auth_len, gfp);
268 if (!secret)
269 return NULL;
270
271 if (ep_key->key) {
272 memcpy(secret->data, ep_key->key->data, ep_key->key->len);
273 offset += ep_key->key->len;
274 }
275
276 memcpy(secret->data + offset, first_vector->data, first_vector->len);
277 offset += first_vector->len;
278
279 memcpy(secret->data + offset, last_vector->data, last_vector->len);
280
281 return secret;
282}
283
284/* Create an association shared key. Follow the algorithm
285 * described in SCTP-AUTH, Section 6.1
286 */
287static struct sctp_auth_bytes *sctp_auth_asoc_create_secret(
288 const struct sctp_association *asoc,
289 struct sctp_shared_key *ep_key,
290 gfp_t gfp)
291{
292 struct sctp_auth_bytes *local_key_vector;
293 struct sctp_auth_bytes *peer_key_vector;
294 struct sctp_auth_bytes *first_vector,
295 *last_vector;
296 struct sctp_auth_bytes *secret = NULL;
297 int cmp;
298
299
300 /* Now we need to build the key vectors
301 * SCTP-AUTH , Section 6.1
302 * The RANDOM parameter, the CHUNKS parameter and the HMAC-ALGO
303 * parameter sent by each endpoint are concatenated as byte vectors.
304 * These parameters include the parameter type, parameter length, and
305 * the parameter value, but padding is omitted; all padding MUST be
306 * removed from this concatenation before proceeding with further
307 * computation of keys. Parameters which were not sent are simply
308 * omitted from the concatenation process. The resulting two vectors
309 * are called the two key vectors.
310 */
311
312 local_key_vector = sctp_auth_make_local_vector(asoc, gfp);
313 peer_key_vector = sctp_auth_make_peer_vector(asoc, gfp);
314
315 if (!peer_key_vector || !local_key_vector)
316 goto out;
317
318 /* Figure out the order in which the key_vectors will be
319 * added to the endpoint shared key.
320 * SCTP-AUTH, Section 6.1:
321 * This is performed by selecting the numerically smaller key
322 * vector and concatenating it to the endpoint pair shared
323 * key, and then concatenating the numerically larger key
324 * vector to that. If the key vectors are equal as numbers
325 * but differ in length, then the concatenation order is the
326 * endpoint shared key, followed by the shorter key vector,
327 * followed by the longer key vector. Otherwise, the key
328 * vectors are identical, and may be concatenated to the
329 * endpoint pair key in any order.
330 */
331 cmp = sctp_auth_compare_vectors(local_key_vector,
332 peer_key_vector);
333 if (cmp < 0) {
334 first_vector = local_key_vector;
335 last_vector = peer_key_vector;
336 } else {
337 first_vector = peer_key_vector;
338 last_vector = local_key_vector;
339 }
340
341 secret = sctp_auth_asoc_set_secret(ep_key, first_vector, last_vector,
342 gfp);
343out:
344 sctp_auth_key_put(local_key_vector);
345 sctp_auth_key_put(peer_key_vector);
346
347 return secret;
348}
349
350/*
351 * Populate the association overlay list with the list
352 * from the endpoint.
353 */
354int sctp_auth_asoc_copy_shkeys(const struct sctp_endpoint *ep,
355 struct sctp_association *asoc,
356 gfp_t gfp)
357{
358 struct sctp_shared_key *sh_key;
359 struct sctp_shared_key *new;
360
361 BUG_ON(!list_empty(&asoc->endpoint_shared_keys));
362
363 key_for_each(sh_key, &ep->endpoint_shared_keys) {
364 new = sctp_auth_shkey_create(sh_key->key_id, gfp);
365 if (!new)
366 goto nomem;
367
368 new->key = sh_key->key;
369 sctp_auth_key_hold(new->key);
370 list_add(&new->key_list, &asoc->endpoint_shared_keys);
371 }
372
373 return 0;
374
375nomem:
376 sctp_auth_destroy_keys(&asoc->endpoint_shared_keys);
377 return -ENOMEM;
378}
379
380static bool sctp_auth_chunk_id_forbidden(__u8 chunk_id)
381{
382 switch (chunk_id) {
383 case SCTP_CID_INIT:
384 case SCTP_CID_INIT_ACK:
385 case SCTP_CID_SHUTDOWN_COMPLETE:
386 case SCTP_CID_AUTH:
387 return true;
388 default:
389 return false;
390 }
391}
392
393/* Verify AUTH parameters copied from a state cookie before they are restored
394 * into an association. When cookie authentication is disabled these fields
395 * are peer-controlled, so they must satisfy the same constraints as locally
396 * generated AUTH parameters.
397 */
398bool sctp_auth_verify_cookie_params(const struct sctp_endpoint *ep,
399 const struct sctp_cookie *cookie)
400{
401 const struct sctp_paramhdr *random;
402 const struct sctp_hmac_algo_param *hmacs;
403 const struct sctp_chunks_param *chunks;
404 u16 hmacs_len, chunks_len;
405 u16 n_hmacs, n_chunks, i;
406 bool has_sha1 = false;
407
408 if (sctp_sk(ep->base.sk)->cookie_auth_enable || !ep->auth_enable)
409 return true;
410
411 random = (const struct sctp_paramhdr *)cookie->auth_random;
412 if (random->type != SCTP_PARAM_RANDOM ||
413 ntohs(random->length) != sizeof(*random) + SCTP_AUTH_RANDOM_LENGTH)
414 return false;
415
416 hmacs = (const struct sctp_hmac_algo_param *)cookie->auth_hmacs;
417 hmacs_len = ntohs(hmacs->param_hdr.length);
418 if (hmacs->param_hdr.type != SCTP_PARAM_HMAC_ALGO ||
419 hmacs_len < sizeof(struct sctp_paramhdr) +
420 sizeof(hmacs->hmac_ids[0]) ||
421 hmacs_len > sizeof(cookie->auth_hmacs) ||
422 (hmacs_len - sizeof(struct sctp_paramhdr)) %
423 sizeof(hmacs->hmac_ids[0]))
424 return false;
425
426 n_hmacs = (hmacs_len - sizeof(struct sctp_paramhdr)) /
427 sizeof(hmacs->hmac_ids[0]);
428 for (i = 0; i < n_hmacs; i++) {
429 u16 hmac_id = ntohs(hmacs->hmac_ids[i]);
430
431 if (!sctp_hmac_supported(hmac_id))
432 return false;
433 if (hmac_id == SCTP_AUTH_HMAC_ID_SHA1)
434 has_sha1 = true;
435 }
436 if (!has_sha1)
437 return false;
438
439 chunks = (const struct sctp_chunks_param *)cookie->auth_chunks;
440 chunks_len = ntohs(chunks->param_hdr.length);
441 if (chunks->param_hdr.type != SCTP_PARAM_CHUNKS ||
442 chunks_len < sizeof(struct sctp_paramhdr) ||
443 chunks_len > sizeof(cookie->auth_chunks))
444 return false;
445
446 n_chunks = chunks_len - sizeof(struct sctp_paramhdr);
447 for (i = 0; i < n_chunks; i++) {
448 if (sctp_auth_chunk_id_forbidden(chunks->chunks[i]))
449 return false;
450 }
451
452 return true;
453}
454
455
456/* Public interface to create the association shared key.
457 * See code above for the algorithm.
458 */
459int sctp_auth_asoc_init_active_key(struct sctp_association *asoc, gfp_t gfp)
460{
461 struct sctp_auth_bytes *secret;
462 struct sctp_shared_key *ep_key;
463 struct sctp_chunk *chunk;
464
465 /* If we don't support AUTH, or peer is not capable
466 * we don't need to do anything.
467 */
468 if (!asoc->peer.auth_capable)
469 return 0;
470
471 /* If the key_id is non-zero and we couldn't find an
472 * endpoint pair shared key, we can't compute the
473 * secret.
474 * For key_id 0, endpoint pair shared key is a NULL key.
475 */
476 ep_key = sctp_auth_get_shkey(asoc, asoc->active_key_id);
477 BUG_ON(!ep_key);
478
479 secret = sctp_auth_asoc_create_secret(asoc, ep_key, gfp);
480 if (!secret)
481 return -ENOMEM;
482
483 sctp_auth_key_put(asoc->asoc_shared_key);
484 asoc->asoc_shared_key = secret;
485 asoc->shkey = ep_key;
486
487 /* Update send queue in case any chunk already in there now
488 * needs authenticating
489 */
490 list_for_each_entry(chunk, &asoc->outqueue.out_chunk_list, list) {
491 if (sctp_auth_send_cid(chunk->chunk_hdr->type, asoc)) {
492 chunk->auth = 1;
493 if (!chunk->shkey) {
494 chunk->shkey = asoc->shkey;
495 sctp_auth_shkey_hold(chunk->shkey);
496 }
497 }
498 }
499
500 return 0;
501}
502
503
504/* Find the endpoint pair shared key based on the key_id */
505struct sctp_shared_key *sctp_auth_get_shkey(
506 const struct sctp_association *asoc,
507 __u16 key_id)
508{
509 struct sctp_shared_key *key;
510
511 /* First search associations set of endpoint pair shared keys */
512 key_for_each(key, &asoc->endpoint_shared_keys) {
513 if (key->key_id == key_id) {
514 if (!key->deactivated)
515 return key;
516 break;
517 }
518 }
519
520 return NULL;
521}
522
523const struct sctp_hmac *sctp_auth_get_hmac(__u16 hmac_id)
524{
525 return &sctp_hmac_list[hmac_id];
526}
527
528/* Get an hmac description information that we can use to build
529 * the AUTH chunk
530 */
531const struct sctp_hmac *
532sctp_auth_asoc_get_hmac(const struct sctp_association *asoc)
533{
534 struct sctp_hmac_algo_param *hmacs;
535 __u16 n_elt;
536 __u16 id = 0;
537 int i;
538
539 /* If we have a default entry, use it */
540 if (asoc->default_hmac_id)
541 return &sctp_hmac_list[asoc->default_hmac_id];
542
543 /* Since we do not have a default entry, find the first entry
544 * we support and return that. Do not cache that id.
545 */
546 hmacs = asoc->peer.peer_hmacs;
547 if (!hmacs)
548 return NULL;
549
550 n_elt = (ntohs(hmacs->param_hdr.length) -
551 sizeof(struct sctp_paramhdr)) >> 1;
552 for (i = 0; i < n_elt; i++) {
553 id = ntohs(hmacs->hmac_ids[i]);
554 if (sctp_hmac_supported(id))
555 return &sctp_hmac_list[id];
556 }
557 return NULL;
558}
559
560static int __sctp_auth_find_hmacid(__be16 *hmacs, int n_elts, __be16 hmac_id)
561{
562 int found = 0;
563 int i;
564
565 for (i = 0; i < n_elts; i++) {
566 if (hmac_id == hmacs[i]) {
567 found = 1;
568 break;
569 }
570 }
571
572 return found;
573}
574
575/* See if the HMAC_ID is one that we claim as supported */
576int sctp_auth_asoc_verify_hmac_id(const struct sctp_association *asoc,
577 __be16 hmac_id)
578{
579 struct sctp_hmac_algo_param *hmacs;
580 __u16 n_elt;
581
582 if (!asoc)
583 return 0;
584
585 hmacs = (struct sctp_hmac_algo_param *)asoc->c.auth_hmacs;
586 n_elt = (ntohs(hmacs->param_hdr.length) -
587 sizeof(struct sctp_paramhdr)) >> 1;
588
589 return __sctp_auth_find_hmacid(hmacs->hmac_ids, n_elt, hmac_id);
590}
591
592
593/* Cache the default HMAC id. This to follow this text from SCTP-AUTH:
594 * Section 6.1:
595 * The receiver of a HMAC-ALGO parameter SHOULD use the first listed
596 * algorithm it supports.
597 */
598void sctp_auth_asoc_set_default_hmac(struct sctp_association *asoc,
599 struct sctp_hmac_algo_param *hmacs)
600{
601 __u16 id;
602 int i;
603 int n_params;
604
605 /* if the default id is already set, use it */
606 if (asoc->default_hmac_id)
607 return;
608
609 n_params = (ntohs(hmacs->param_hdr.length) -
610 sizeof(struct sctp_paramhdr)) >> 1;
611 for (i = 0; i < n_params; i++) {
612 id = ntohs(hmacs->hmac_ids[i]);
613 if (sctp_hmac_supported(id)) {
614 asoc->default_hmac_id = id;
615 break;
616 }
617 }
618}
619
620
621/* Check to see if the given chunk is supposed to be authenticated */
622static int __sctp_auth_cid(enum sctp_cid chunk, struct sctp_chunks_param *param)
623{
624 unsigned short len;
625 int found = 0;
626 int i;
627
628 if (!param || param->param_hdr.length == 0)
629 return 0;
630
631 len = ntohs(param->param_hdr.length) - sizeof(struct sctp_paramhdr);
632
633 /* SCTP-AUTH, Section 3.2
634 * The chunk types for INIT, INIT-ACK, SHUTDOWN-COMPLETE and AUTH
635 * chunks MUST NOT be listed in the CHUNKS parameter. However, if
636 * a CHUNKS parameter is received then the types for INIT, INIT-ACK,
637 * SHUTDOWN-COMPLETE and AUTH chunks MUST be ignored.
638 */
639 for (i = 0; !found && i < len; i++) {
640 switch (param->chunks[i]) {
641 case SCTP_CID_INIT:
642 case SCTP_CID_INIT_ACK:
643 case SCTP_CID_SHUTDOWN_COMPLETE:
644 case SCTP_CID_AUTH:
645 break;
646
647 default:
648 if (param->chunks[i] == chunk)
649 found = 1;
650 break;
651 }
652 }
653
654 return found;
655}
656
657/* Check if peer requested that this chunk is authenticated */
658int sctp_auth_send_cid(enum sctp_cid chunk, const struct sctp_association *asoc)
659{
660 if (!asoc)
661 return 0;
662
663 if (!asoc->peer.auth_capable)
664 return 0;
665
666 return __sctp_auth_cid(chunk, asoc->peer.peer_chunks);
667}
668
669/* Check if we requested that peer authenticate this chunk. */
670int sctp_auth_recv_cid(enum sctp_cid chunk, const struct sctp_association *asoc)
671{
672 if (!asoc)
673 return 0;
674
675 if (!asoc->peer.auth_capable)
676 return 0;
677
678 return __sctp_auth_cid(chunk,
679 (struct sctp_chunks_param *)asoc->c.auth_chunks);
680}
681
682/* SCTP-AUTH: Section 6.2:
683 * The sender MUST calculate the MAC as described in RFC2104 [2] using
684 * the hash function H as described by the MAC Identifier and the shared
685 * association key K based on the endpoint pair shared key described by
686 * the shared key identifier. The 'data' used for the computation of
687 * the AUTH-chunk is given by the AUTH chunk with its HMAC field set to
688 * zero (as shown in Figure 6) followed by all chunks that are placed
689 * after the AUTH chunk in the SCTP packet.
690 */
691int sctp_auth_calculate_hmac(const struct sctp_association *asoc,
692 struct sk_buff *skb, struct sctp_auth_chunk *auth,
693 struct sctp_shared_key *ep_key, gfp_t gfp)
694{
695 struct sctp_auth_bytes *asoc_key;
696 __u16 key_id, hmac_id;
697 int free_key = 0;
698 size_t data_len;
699 __u8 *digest;
700
701 /* Extract the info we need:
702 * - hmac id
703 * - key id
704 */
705 key_id = ntohs(auth->auth_hdr.shkey_id);
706 hmac_id = ntohs(auth->auth_hdr.hmac_id);
707
708 if (key_id == asoc->active_key_id)
709 asoc_key = asoc->asoc_shared_key;
710 else {
711 /* ep_key can't be NULL here */
712 asoc_key = sctp_auth_asoc_create_secret(asoc, ep_key, gfp);
713 if (!asoc_key)
714 return -ENOMEM;
715
716 free_key = 1;
717 }
718
719 data_len = skb_tail_pointer(skb) - (unsigned char *)auth;
720 digest = (u8 *)(&auth->auth_hdr + 1);
721 if (hmac_id == SCTP_AUTH_HMAC_ID_SHA1) {
722 hmac_sha1_usingrawkey(asoc_key->data, asoc_key->len,
723 (const u8 *)auth, data_len, digest);
724 } else {
725 WARN_ON_ONCE(hmac_id != SCTP_AUTH_HMAC_ID_SHA256);
726 hmac_sha256_usingrawkey(asoc_key->data, asoc_key->len,
727 (const u8 *)auth, data_len, digest);
728 }
729
730 if (free_key)
731 sctp_auth_key_put(asoc_key);
732
733 return 0;
734}
735
736/* API Helpers */
737
738/* Add a chunk to the endpoint authenticated chunk list */
739int sctp_auth_ep_add_chunkid(struct sctp_endpoint *ep, __u8 chunk_id)
740{
741 struct sctp_chunks_param *p = ep->auth_chunk_list;
742 __u16 nchunks;
743 __u16 param_len;
744
745 /* If this chunk is already specified, we are done */
746 if (__sctp_auth_cid(chunk_id, p))
747 return 0;
748
749 /* Check if we can add this chunk to the array */
750 param_len = ntohs(p->param_hdr.length);
751 nchunks = param_len - sizeof(struct sctp_paramhdr);
752 if (nchunks == SCTP_AUTH_MAX_CHUNKS)
753 return -EINVAL;
754
755 p->chunks[nchunks] = chunk_id;
756 p->param_hdr.length = htons(param_len + 1);
757 return 0;
758}
759
760/* Add hmac identifires to the endpoint list of supported hmac ids */
761int sctp_auth_ep_set_hmacs(struct sctp_endpoint *ep,
762 struct sctp_hmacalgo *hmacs)
763{
764 int has_sha1 = 0;
765 __u16 id;
766 int i;
767
768 /* Scan the list looking for unsupported id. Also make sure that
769 * SHA1 is specified.
770 */
771 for (i = 0; i < hmacs->shmac_num_idents; i++) {
772 id = hmacs->shmac_idents[i];
773
774 if (!sctp_hmac_supported(id))
775 return -EOPNOTSUPP;
776
777 if (SCTP_AUTH_HMAC_ID_SHA1 == id)
778 has_sha1 = 1;
779 }
780
781 if (!has_sha1)
782 return -EINVAL;
783
784 for (i = 0; i < hmacs->shmac_num_idents; i++)
785 ep->auth_hmacs_list->hmac_ids[i] =
786 htons(hmacs->shmac_idents[i]);
787 ep->auth_hmacs_list->param_hdr.length =
788 htons(sizeof(struct sctp_paramhdr) +
789 hmacs->shmac_num_idents * sizeof(__u16));
790 return 0;
791}
792
793/* Set a new shared key on either endpoint or association. If the
794 * key with a same ID already exists, replace the key (remove the
795 * old key and add a new one).
796 */
797int sctp_auth_set_key(struct sctp_endpoint *ep,
798 struct sctp_association *asoc,
799 struct sctp_authkey *auth_key)
800{
801 struct sctp_shared_key *cur_key, *shkey;
802 struct sctp_auth_bytes *key;
803 struct list_head *sh_keys;
804 int replace = 0;
805
806 /* Try to find the given key id to see if
807 * we are doing a replace, or adding a new key
808 */
809 if (asoc) {
810 if (!asoc->peer.auth_capable)
811 return -EACCES;
812 sh_keys = &asoc->endpoint_shared_keys;
813 } else {
814 if (!ep->auth_enable)
815 return -EACCES;
816 sh_keys = &ep->endpoint_shared_keys;
817 }
818
819 key_for_each(shkey, sh_keys) {
820 if (shkey->key_id == auth_key->sca_keynumber) {
821 replace = 1;
822 break;
823 }
824 }
825
826 cur_key = sctp_auth_shkey_create(auth_key->sca_keynumber, GFP_KERNEL);
827 if (!cur_key)
828 return -ENOMEM;
829
830 /* Create a new key data based on the info passed in */
831 key = sctp_auth_create_key(auth_key->sca_keylength, GFP_KERNEL);
832 if (!key) {
833 kfree(cur_key);
834 return -ENOMEM;
835 }
836
837 memcpy(key->data, &auth_key->sca_key[0], auth_key->sca_keylength);
838 cur_key->key = key;
839
840 if (!replace) {
841 list_add(&cur_key->key_list, sh_keys);
842 return 0;
843 }
844
845 list_del_init(&shkey->key_list);
846 list_add(&cur_key->key_list, sh_keys);
847
848 if (asoc && asoc->active_key_id == auth_key->sca_keynumber &&
849 sctp_auth_asoc_init_active_key(asoc, GFP_KERNEL)) {
850 list_del_init(&cur_key->key_list);
851 sctp_auth_shkey_release(cur_key);
852 list_add(&shkey->key_list, sh_keys);
853 return -ENOMEM;
854 }
855
856 sctp_auth_shkey_release(shkey);
857 return 0;
858}
859
860int sctp_auth_set_active_key(struct sctp_endpoint *ep,
861 struct sctp_association *asoc,
862 __u16 key_id)
863{
864 struct sctp_shared_key *key;
865 struct list_head *sh_keys;
866 int found = 0;
867
868 /* The key identifier MUST correst to an existing key */
869 if (asoc) {
870 if (!asoc->peer.auth_capable)
871 return -EACCES;
872 sh_keys = &asoc->endpoint_shared_keys;
873 } else {
874 if (!ep->auth_enable)
875 return -EACCES;
876 sh_keys = &ep->endpoint_shared_keys;
877 }
878
879 key_for_each(key, sh_keys) {
880 if (key->key_id == key_id) {
881 found = 1;
882 break;
883 }
884 }
885
886 if (!found || key->deactivated)
887 return -EINVAL;
888
889 if (asoc) {
890 __u16 active_key_id = asoc->active_key_id;
891
892 asoc->active_key_id = key_id;
893 if (sctp_auth_asoc_init_active_key(asoc, GFP_KERNEL)) {
894 asoc->active_key_id = active_key_id;
895 return -ENOMEM;
896 }
897 } else
898 ep->active_key_id = key_id;
899
900 return 0;
901}
902
903int sctp_auth_del_key_id(struct sctp_endpoint *ep,
904 struct sctp_association *asoc,
905 __u16 key_id)
906{
907 struct sctp_shared_key *key;
908 struct list_head *sh_keys;
909 int found = 0;
910
911 /* The key identifier MUST NOT be the current active key
912 * The key identifier MUST correst to an existing key
913 */
914 if (asoc) {
915 if (!asoc->peer.auth_capable)
916 return -EACCES;
917 if (asoc->active_key_id == key_id)
918 return -EINVAL;
919
920 sh_keys = &asoc->endpoint_shared_keys;
921 } else {
922 if (!ep->auth_enable)
923 return -EACCES;
924 if (ep->active_key_id == key_id)
925 return -EINVAL;
926
927 sh_keys = &ep->endpoint_shared_keys;
928 }
929
930 key_for_each(key, sh_keys) {
931 if (key->key_id == key_id) {
932 found = 1;
933 break;
934 }
935 }
936
937 if (!found)
938 return -EINVAL;
939
940 /* Delete the shared key */
941 list_del_init(&key->key_list);
942 sctp_auth_shkey_release(key);
943
944 return 0;
945}
946
947int sctp_auth_deact_key_id(struct sctp_endpoint *ep,
948 struct sctp_association *asoc, __u16 key_id)
949{
950 struct sctp_shared_key *key;
951 struct list_head *sh_keys;
952 int found = 0;
953
954 /* The key identifier MUST NOT be the current active key
955 * The key identifier MUST correst to an existing key
956 */
957 if (asoc) {
958 if (!asoc->peer.auth_capable)
959 return -EACCES;
960 if (asoc->active_key_id == key_id)
961 return -EINVAL;
962
963 sh_keys = &asoc->endpoint_shared_keys;
964 } else {
965 if (!ep->auth_enable)
966 return -EACCES;
967 if (ep->active_key_id == key_id)
968 return -EINVAL;
969
970 sh_keys = &ep->endpoint_shared_keys;
971 }
972
973 key_for_each(key, sh_keys) {
974 if (key->key_id == key_id) {
975 found = 1;
976 break;
977 }
978 }
979
980 if (!found)
981 return -EINVAL;
982
983 /* refcnt == 1 and !list_empty mean it's not being used anywhere
984 * and deactivated will be set, so it's time to notify userland
985 * that this shkey can be freed.
986 */
987 if (asoc && !list_empty(&key->key_list) &&
988 refcount_read(&key->refcnt) == 1) {
989 struct sctp_ulpevent *ev;
990
991 ev = sctp_ulpevent_make_authkey(asoc, key->key_id,
992 SCTP_AUTH_FREE_KEY, GFP_KERNEL);
993 if (ev)
994 asoc->stream.si->enqueue_event(&asoc->ulpq, ev);
995 }
996
997 key->deactivated = 1;
998
999 return 0;
1000}
1001
1002int sctp_auth_init(struct sctp_endpoint *ep, gfp_t gfp)
1003{
1004 /* Allocate space for HMACS and CHUNKS authentication
1005 * variables. There are arrays that we encode directly
1006 * into parameters to make the rest of the operations easier.
1007 */
1008 if (!ep->auth_hmacs_list) {
1009 struct sctp_hmac_algo_param *auth_hmacs;
1010
1011 auth_hmacs = kzalloc_flex(*auth_hmacs, hmac_ids,
1012 SCTP_AUTH_NUM_HMACS, gfp);
1013 if (!auth_hmacs)
1014 goto nomem;
1015 /* Initialize the HMACS parameter.
1016 * SCTP-AUTH: Section 3.3
1017 * Every endpoint supporting SCTP chunk authentication MUST
1018 * support the HMAC based on the SHA-1 algorithm.
1019 */
1020 auth_hmacs->param_hdr.type = SCTP_PARAM_HMAC_ALGO;
1021 auth_hmacs->param_hdr.length =
1022 htons(sizeof(struct sctp_paramhdr) + 2);
1023 auth_hmacs->hmac_ids[0] = htons(SCTP_AUTH_HMAC_ID_SHA1);
1024 ep->auth_hmacs_list = auth_hmacs;
1025 }
1026
1027 if (!ep->auth_chunk_list) {
1028 struct sctp_chunks_param *auth_chunks;
1029
1030 auth_chunks = kzalloc(sizeof(*auth_chunks) +
1031 SCTP_NUM_CHUNK_TYPES, gfp);
1032 if (!auth_chunks)
1033 goto nomem;
1034 /* Initialize the CHUNKS parameter */
1035 auth_chunks->param_hdr.type = SCTP_PARAM_CHUNKS;
1036 auth_chunks->param_hdr.length =
1037 htons(sizeof(struct sctp_paramhdr));
1038 ep->auth_chunk_list = auth_chunks;
1039 }
1040
1041 return 0;
1042
1043nomem:
1044 /* Free all allocations */
1045 kfree(ep->auth_hmacs_list);
1046 kfree(ep->auth_chunk_list);
1047 ep->auth_hmacs_list = NULL;
1048 ep->auth_chunk_list = NULL;
1049 return -ENOMEM;
1050}
1051
1052void sctp_auth_free(struct sctp_endpoint *ep)
1053{
1054 kfree(ep->auth_hmacs_list);
1055 kfree(ep->auth_chunk_list);
1056 ep->auth_hmacs_list = NULL;
1057 ep->auth_chunk_list = NULL;
1058}