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Vlad Yasevich60c778b2008-01-11 09:57:09 -05001/* SCTP kernel implementation
Vlad Yasevich1f485642007-10-09 01:15:59 -07002 * (C) Copyright 2007 Hewlett-Packard Development Company, L.P.
3 *
Vlad Yasevich60c778b2008-01-11 09:57:09 -05004 * This file is part of the SCTP kernel implementation
Vlad Yasevich1f485642007-10-09 01:15:59 -07005 *
Vlad Yasevich60c778b2008-01-11 09:57:09 -05006 * This SCTP implementation is free software;
Vlad Yasevich1f485642007-10-09 01:15:59 -07007 * 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 *
Vlad Yasevich60c778b2008-01-11 09:57:09 -050012 * This SCTP implementation is distributed in the hope that it
Vlad Yasevich1f485642007-10-09 01:15:59 -070013 * will be useful, but WITHOUT ANY WARRANTY; without even the implied
14 * ************************
15 * warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
16 * See the GNU General Public License for more details.
17 *
18 * You should have received a copy of the GNU General Public License
19 * along with GNU CC; see the file COPYING. If not, write to
20 * the Free Software Foundation, 59 Temple Place - Suite 330,
21 * Boston, MA 02111-1307, USA.
22 *
23 * Please send any bug reports or fixes you make to the
24 * email address(es):
25 * lksctp developers <lksctp-developers@lists.sourceforge.net>
26 *
27 * Or submit a bug report through the following website:
28 * http://www.sf.net/projects/lksctp
29 *
30 * Written or modified by:
31 * Vlad Yasevich <vladislav.yasevich@hp.com>
32 *
33 * Any bugs reported given to us we will try to fix... any fixes shared will
34 * be incorporated into the next SCTP release.
35 */
36
Tejun Heo5a0e3ad2010-03-24 17:04:11 +090037#include <linux/slab.h>
Vlad Yasevich1f485642007-10-09 01:15:59 -070038#include <linux/types.h>
39#include <linux/crypto.h>
40#include <linux/scatterlist.h>
41#include <net/sctp/sctp.h>
42#include <net/sctp/auth.h>
43
44static struct sctp_hmac sctp_hmac_list[SCTP_AUTH_NUM_HMACS] = {
45 {
46 /* id 0 is reserved. as all 0 */
47 .hmac_id = SCTP_AUTH_HMAC_ID_RESERVED_0,
48 },
49 {
50 .hmac_id = SCTP_AUTH_HMAC_ID_SHA1,
51 .hmac_name="hmac(sha1)",
52 .hmac_len = SCTP_SHA1_SIG_SIZE,
53 },
54 {
55 /* id 2 is reserved as well */
56 .hmac_id = SCTP_AUTH_HMAC_ID_RESERVED_2,
57 },
Vlad Yasevichb7e0fe92007-11-29 09:53:52 -050058#if defined (CONFIG_CRYPTO_SHA256) || defined (CONFIG_CRYPTO_SHA256_MODULE)
Vlad Yasevich1f485642007-10-09 01:15:59 -070059 {
60 .hmac_id = SCTP_AUTH_HMAC_ID_SHA256,
61 .hmac_name="hmac(sha256)",
62 .hmac_len = SCTP_SHA256_SIG_SIZE,
63 }
Vlad Yasevichb7e0fe92007-11-29 09:53:52 -050064#endif
Vlad Yasevich1f485642007-10-09 01:15:59 -070065};
66
67
68void sctp_auth_key_put(struct sctp_auth_bytes *key)
69{
70 if (!key)
71 return;
72
73 if (atomic_dec_and_test(&key->refcnt)) {
Daniel Borkmann586c31f2013-02-07 00:55:37 +000074 kzfree(key);
Vlad Yasevich1f485642007-10-09 01:15:59 -070075 SCTP_DBG_OBJCNT_DEC(keys);
76 }
77}
78
79/* Create a new key structure of a given length */
80static struct sctp_auth_bytes *sctp_auth_create_key(__u32 key_len, gfp_t gfp)
81{
82 struct sctp_auth_bytes *key;
83
Vlad Yasevich30c22352008-08-25 15:16:19 -070084 /* Verify that we are not going to overflow INT_MAX */
Xi Wangc89304b2011-11-29 09:26:30 +000085 if (key_len > (INT_MAX - sizeof(struct sctp_auth_bytes)))
Vlad Yasevich30c22352008-08-25 15:16:19 -070086 return NULL;
87
Vlad Yasevich1f485642007-10-09 01:15:59 -070088 /* Allocate the shared key */
89 key = kmalloc(sizeof(struct sctp_auth_bytes) + key_len, gfp);
90 if (!key)
91 return NULL;
92
93 key->len = key_len;
94 atomic_set(&key->refcnt, 1);
95 SCTP_DBG_OBJCNT_INC(keys);
96
97 return key;
98}
99
100/* Create a new shared key container with a give key id */
101struct sctp_shared_key *sctp_auth_shkey_create(__u16 key_id, gfp_t gfp)
102{
103 struct sctp_shared_key *new;
104
105 /* Allocate the shared key container */
106 new = kzalloc(sizeof(struct sctp_shared_key), gfp);
107 if (!new)
108 return NULL;
109
110 INIT_LIST_HEAD(&new->key_list);
111 new->key_id = key_id;
112
113 return new;
114}
115
Lucas De Marchi25985ed2011-03-30 22:57:33 -0300116/* Free the shared key structure */
Adrian Bunk8ad7c62b2007-10-26 04:21:23 -0700117static void sctp_auth_shkey_free(struct sctp_shared_key *sh_key)
Vlad Yasevich1f485642007-10-09 01:15:59 -0700118{
119 BUG_ON(!list_empty(&sh_key->key_list));
120 sctp_auth_key_put(sh_key->key);
121 sh_key->key = NULL;
122 kfree(sh_key);
123}
124
Lucas De Marchi25985ed2011-03-30 22:57:33 -0300125/* Destroy the entire key list. This is done during the
Vlad Yasevich1f485642007-10-09 01:15:59 -0700126 * associon and endpoint free process.
127 */
128void sctp_auth_destroy_keys(struct list_head *keys)
129{
130 struct sctp_shared_key *ep_key;
131 struct sctp_shared_key *tmp;
132
133 if (list_empty(keys))
134 return;
135
136 key_for_each_safe(ep_key, tmp, keys) {
137 list_del_init(&ep_key->key_list);
138 sctp_auth_shkey_free(ep_key);
139 }
140}
141
142/* Compare two byte vectors as numbers. Return values
143 * are:
144 * 0 - vectors are equal
Frederik Schwarzer025dfda2008-10-16 19:02:37 +0200145 * < 0 - vector 1 is smaller than vector2
146 * > 0 - vector 1 is greater than vector2
Vlad Yasevich1f485642007-10-09 01:15:59 -0700147 *
148 * Algorithm is:
149 * This is performed by selecting the numerically smaller key vector...
150 * If the key vectors are equal as numbers but differ in length ...
151 * the shorter vector is considered smaller
152 *
153 * Examples (with small values):
154 * 000123456789 > 123456789 (first number is longer)
155 * 000123456789 < 234567891 (second number is larger numerically)
156 * 123456789 > 2345678 (first number is both larger & longer)
157 */
158static int sctp_auth_compare_vectors(struct sctp_auth_bytes *vector1,
159 struct sctp_auth_bytes *vector2)
160{
161 int diff;
162 int i;
163 const __u8 *longer;
164
165 diff = vector1->len - vector2->len;
166 if (diff) {
167 longer = (diff > 0) ? vector1->data : vector2->data;
168
169 /* Check to see if the longer number is
170 * lead-zero padded. If it is not, it
171 * is automatically larger numerically.
172 */
173 for (i = 0; i < abs(diff); i++ ) {
174 if (longer[i] != 0)
175 return diff;
176 }
177 }
178
179 /* lengths are the same, compare numbers */
180 return memcmp(vector1->data, vector2->data, vector1->len);
181}
182
183/*
184 * Create a key vector as described in SCTP-AUTH, Section 6.1
185 * The RANDOM parameter, the CHUNKS parameter and the HMAC-ALGO
186 * parameter sent by each endpoint are concatenated as byte vectors.
187 * These parameters include the parameter type, parameter length, and
188 * the parameter value, but padding is omitted; all padding MUST be
189 * removed from this concatenation before proceeding with further
190 * computation of keys. Parameters which were not sent are simply
191 * omitted from the concatenation process. The resulting two vectors
192 * are called the two key vectors.
193 */
194static struct sctp_auth_bytes *sctp_auth_make_key_vector(
195 sctp_random_param_t *random,
196 sctp_chunks_param_t *chunks,
197 sctp_hmac_algo_param_t *hmacs,
198 gfp_t gfp)
199{
200 struct sctp_auth_bytes *new;
201 __u32 len;
202 __u32 offset = 0;
Daniel Borkmann241448c2013-02-07 01:41:39 +0000203 __u16 random_len, hmacs_len, chunks_len = 0;
Vlad Yasevich1f485642007-10-09 01:15:59 -0700204
Daniel Borkmann241448c2013-02-07 01:41:39 +0000205 random_len = ntohs(random->param_hdr.length);
206 hmacs_len = ntohs(hmacs->param_hdr.length);
207 if (chunks)
208 chunks_len = ntohs(chunks->param_hdr.length);
209
210 len = random_len + hmacs_len + chunks_len;
Vlad Yasevich1f485642007-10-09 01:15:59 -0700211
Daniel Borkmann03536e22013-02-07 23:22:58 +0000212 new = sctp_auth_create_key(len, gfp);
Vlad Yasevich1f485642007-10-09 01:15:59 -0700213 if (!new)
214 return NULL;
215
Daniel Borkmann241448c2013-02-07 01:41:39 +0000216 memcpy(new->data, random, random_len);
217 offset += random_len;
Vlad Yasevich1f485642007-10-09 01:15:59 -0700218
219 if (chunks) {
Daniel Borkmann241448c2013-02-07 01:41:39 +0000220 memcpy(new->data + offset, chunks, chunks_len);
221 offset += chunks_len;
Vlad Yasevich1f485642007-10-09 01:15:59 -0700222 }
223
Daniel Borkmann241448c2013-02-07 01:41:39 +0000224 memcpy(new->data + offset, hmacs, hmacs_len);
Vlad Yasevich1f485642007-10-09 01:15:59 -0700225
226 return new;
227}
228
229
230/* Make a key vector based on our local parameters */
Adrian Bunk8ad7c62b2007-10-26 04:21:23 -0700231static struct sctp_auth_bytes *sctp_auth_make_local_vector(
Vlad Yasevich1f485642007-10-09 01:15:59 -0700232 const struct sctp_association *asoc,
233 gfp_t gfp)
234{
235 return sctp_auth_make_key_vector(
236 (sctp_random_param_t*)asoc->c.auth_random,
237 (sctp_chunks_param_t*)asoc->c.auth_chunks,
238 (sctp_hmac_algo_param_t*)asoc->c.auth_hmacs,
239 gfp);
240}
241
242/* Make a key vector based on peer's parameters */
Adrian Bunk8ad7c62b2007-10-26 04:21:23 -0700243static struct sctp_auth_bytes *sctp_auth_make_peer_vector(
Vlad Yasevich1f485642007-10-09 01:15:59 -0700244 const struct sctp_association *asoc,
245 gfp_t gfp)
246{
247 return sctp_auth_make_key_vector(asoc->peer.peer_random,
248 asoc->peer.peer_chunks,
249 asoc->peer.peer_hmacs,
250 gfp);
251}
252
253
254/* Set the value of the association shared key base on the parameters
255 * given. The algorithm is:
256 * From the endpoint pair shared keys and the key vectors the
257 * association shared keys are computed. This is performed by selecting
258 * the numerically smaller key vector and concatenating it to the
259 * endpoint pair shared key, and then concatenating the numerically
260 * larger key vector to that. The result of the concatenation is the
261 * association shared key.
262 */
263static struct sctp_auth_bytes *sctp_auth_asoc_set_secret(
264 struct sctp_shared_key *ep_key,
265 struct sctp_auth_bytes *first_vector,
266 struct sctp_auth_bytes *last_vector,
267 gfp_t gfp)
268{
269 struct sctp_auth_bytes *secret;
270 __u32 offset = 0;
271 __u32 auth_len;
272
273 auth_len = first_vector->len + last_vector->len;
274 if (ep_key->key)
275 auth_len += ep_key->key->len;
276
277 secret = sctp_auth_create_key(auth_len, gfp);
278 if (!secret)
279 return NULL;
280
281 if (ep_key->key) {
282 memcpy(secret->data, ep_key->key->data, ep_key->key->len);
283 offset += ep_key->key->len;
284 }
285
286 memcpy(secret->data + offset, first_vector->data, first_vector->len);
287 offset += first_vector->len;
288
289 memcpy(secret->data + offset, last_vector->data, last_vector->len);
290
291 return secret;
292}
293
294/* Create an association shared key. Follow the algorithm
295 * described in SCTP-AUTH, Section 6.1
296 */
297static struct sctp_auth_bytes *sctp_auth_asoc_create_secret(
298 const struct sctp_association *asoc,
299 struct sctp_shared_key *ep_key,
300 gfp_t gfp)
301{
302 struct sctp_auth_bytes *local_key_vector;
303 struct sctp_auth_bytes *peer_key_vector;
304 struct sctp_auth_bytes *first_vector,
305 *last_vector;
306 struct sctp_auth_bytes *secret = NULL;
307 int cmp;
308
309
310 /* Now we need to build the key vectors
311 * SCTP-AUTH , Section 6.1
312 * The RANDOM parameter, the CHUNKS parameter and the HMAC-ALGO
313 * parameter sent by each endpoint are concatenated as byte vectors.
314 * These parameters include the parameter type, parameter length, and
315 * the parameter value, but padding is omitted; all padding MUST be
316 * removed from this concatenation before proceeding with further
317 * computation of keys. Parameters which were not sent are simply
318 * omitted from the concatenation process. The resulting two vectors
319 * are called the two key vectors.
320 */
321
322 local_key_vector = sctp_auth_make_local_vector(asoc, gfp);
323 peer_key_vector = sctp_auth_make_peer_vector(asoc, gfp);
324
325 if (!peer_key_vector || !local_key_vector)
326 goto out;
327
Lucas De Marchi25985ed2011-03-30 22:57:33 -0300328 /* Figure out the order in which the key_vectors will be
Vlad Yasevich1f485642007-10-09 01:15:59 -0700329 * added to the endpoint shared key.
330 * SCTP-AUTH, Section 6.1:
331 * This is performed by selecting the numerically smaller key
332 * vector and concatenating it to the endpoint pair shared
333 * key, and then concatenating the numerically larger key
334 * vector to that. If the key vectors are equal as numbers
335 * but differ in length, then the concatenation order is the
336 * endpoint shared key, followed by the shorter key vector,
337 * followed by the longer key vector. Otherwise, the key
338 * vectors are identical, and may be concatenated to the
339 * endpoint pair key in any order.
340 */
341 cmp = sctp_auth_compare_vectors(local_key_vector,
342 peer_key_vector);
343 if (cmp < 0) {
344 first_vector = local_key_vector;
345 last_vector = peer_key_vector;
346 } else {
347 first_vector = peer_key_vector;
348 last_vector = local_key_vector;
349 }
350
351 secret = sctp_auth_asoc_set_secret(ep_key, first_vector, last_vector,
352 gfp);
353out:
Daniel Borkmann03536e22013-02-07 23:22:58 +0000354 sctp_auth_key_put(local_key_vector);
355 sctp_auth_key_put(peer_key_vector);
Vlad Yasevich1f485642007-10-09 01:15:59 -0700356
357 return secret;
358}
359
360/*
361 * Populate the association overlay list with the list
362 * from the endpoint.
363 */
364int sctp_auth_asoc_copy_shkeys(const struct sctp_endpoint *ep,
365 struct sctp_association *asoc,
366 gfp_t gfp)
367{
368 struct sctp_shared_key *sh_key;
369 struct sctp_shared_key *new;
370
371 BUG_ON(!list_empty(&asoc->endpoint_shared_keys));
372
373 key_for_each(sh_key, &ep->endpoint_shared_keys) {
374 new = sctp_auth_shkey_create(sh_key->key_id, gfp);
375 if (!new)
376 goto nomem;
377
378 new->key = sh_key->key;
379 sctp_auth_key_hold(new->key);
380 list_add(&new->key_list, &asoc->endpoint_shared_keys);
381 }
382
383 return 0;
384
385nomem:
386 sctp_auth_destroy_keys(&asoc->endpoint_shared_keys);
387 return -ENOMEM;
388}
389
390
391/* Public interface to creat the association shared key.
392 * See code above for the algorithm.
393 */
394int sctp_auth_asoc_init_active_key(struct sctp_association *asoc, gfp_t gfp)
395{
Eric W. Biedermane1fc3b12012-08-07 07:29:57 +0000396 struct net *net = sock_net(asoc->base.sk);
Vlad Yasevich1f485642007-10-09 01:15:59 -0700397 struct sctp_auth_bytes *secret;
398 struct sctp_shared_key *ep_key;
399
400 /* If we don't support AUTH, or peer is not capable
401 * we don't need to do anything.
402 */
Eric W. Biedermane1fc3b12012-08-07 07:29:57 +0000403 if (!net->sctp.auth_enable || !asoc->peer.auth_capable)
Vlad Yasevich1f485642007-10-09 01:15:59 -0700404 return 0;
405
406 /* If the key_id is non-zero and we couldn't find an
407 * endpoint pair shared key, we can't compute the
408 * secret.
409 * For key_id 0, endpoint pair shared key is a NULL key.
410 */
411 ep_key = sctp_auth_get_shkey(asoc, asoc->active_key_id);
412 BUG_ON(!ep_key);
413
414 secret = sctp_auth_asoc_create_secret(asoc, ep_key, gfp);
415 if (!secret)
416 return -ENOMEM;
417
418 sctp_auth_key_put(asoc->asoc_shared_key);
419 asoc->asoc_shared_key = secret;
420
421 return 0;
422}
423
424
425/* Find the endpoint pair shared key based on the key_id */
426struct sctp_shared_key *sctp_auth_get_shkey(
427 const struct sctp_association *asoc,
428 __u16 key_id)
429{
Wei Yongjun7cc08b52008-02-05 03:03:06 -0800430 struct sctp_shared_key *key;
Vlad Yasevich1f485642007-10-09 01:15:59 -0700431
432 /* First search associations set of endpoint pair shared keys */
433 key_for_each(key, &asoc->endpoint_shared_keys) {
434 if (key->key_id == key_id)
Wei Yongjun7cc08b52008-02-05 03:03:06 -0800435 return key;
Vlad Yasevich1f485642007-10-09 01:15:59 -0700436 }
437
Wei Yongjun7cc08b52008-02-05 03:03:06 -0800438 return NULL;
Vlad Yasevich1f485642007-10-09 01:15:59 -0700439}
440
441/*
442 * Initialize all the possible digest transforms that we can use. Right now
443 * now, the supported digests are SHA1 and SHA256. We do this here once
444 * because of the restrictiong that transforms may only be allocated in
445 * user context. This forces us to pre-allocated all possible transforms
446 * at the endpoint init time.
447 */
448int sctp_auth_init_hmacs(struct sctp_endpoint *ep, gfp_t gfp)
449{
Eric W. Biedermane1fc3b12012-08-07 07:29:57 +0000450 struct net *net = sock_net(ep->base.sk);
Vlad Yasevich1f485642007-10-09 01:15:59 -0700451 struct crypto_hash *tfm = NULL;
452 __u16 id;
453
454 /* if the transforms are already allocted, we are done */
Eric W. Biedermane1fc3b12012-08-07 07:29:57 +0000455 if (!net->sctp.auth_enable) {
Vlad Yasevich1f485642007-10-09 01:15:59 -0700456 ep->auth_hmacs = NULL;
457 return 0;
458 }
459
460 if (ep->auth_hmacs)
461 return 0;
462
463 /* Allocated the array of pointers to transorms */
464 ep->auth_hmacs = kzalloc(
465 sizeof(struct crypto_hash *) * SCTP_AUTH_NUM_HMACS,
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_hash(sctp_hmac_list[id].hmac_name, 0,
486 CRYPTO_ALG_ASYNC);
487 if (IS_ERR(tfm))
488 goto out_err;
489
490 ep->auth_hmacs[id] = tfm;
491 }
492
493 return 0;
494
495out_err:
Coly Li73ac36e2009-01-07 18:09:16 -0800496 /* Clean up any successful allocations */
Vlad Yasevich1f485642007-10-09 01:15:59 -0700497 sctp_auth_destroy_hmacs(ep->auth_hmacs);
498 return -ENOMEM;
499}
500
501/* Destroy the hmac tfm array */
502void sctp_auth_destroy_hmacs(struct crypto_hash *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 {
511 if (auth_hmacs[i])
512 crypto_free_hash(auth_hmacs[i]);
513 }
514 kfree(auth_hmacs);
515}
516
517
518struct sctp_hmac *sctp_auth_get_hmac(__u16 hmac_id)
519{
520 return &sctp_hmac_list[hmac_id];
521}
522
523/* Get an hmac description information that we can use to build
524 * the AUTH chunk
525 */
526struct sctp_hmac *sctp_auth_asoc_get_hmac(const struct sctp_association *asoc)
527{
528 struct sctp_hmac_algo_param *hmacs;
529 __u16 n_elt;
530 __u16 id = 0;
531 int i;
532
533 /* If we have a default entry, use it */
534 if (asoc->default_hmac_id)
535 return &sctp_hmac_list[asoc->default_hmac_id];
536
537 /* Since we do not have a default entry, find the first entry
538 * we support and return that. Do not cache that id.
539 */
540 hmacs = asoc->peer.peer_hmacs;
541 if (!hmacs)
542 return NULL;
543
544 n_elt = (ntohs(hmacs->param_hdr.length) - sizeof(sctp_paramhdr_t)) >> 1;
545 for (i = 0; i < n_elt; i++) {
546 id = ntohs(hmacs->hmac_ids[i]);
547
548 /* Check the id is in the supported range */
Dan Rosenberg51e97a12010-10-01 11:51:47 +0000549 if (id > SCTP_AUTH_HMAC_ID_MAX) {
550 id = 0;
Vlad Yasevich1f485642007-10-09 01:15:59 -0700551 continue;
Dan Rosenberg51e97a12010-10-01 11:51:47 +0000552 }
Vlad Yasevich1f485642007-10-09 01:15:59 -0700553
554 /* See is we support the id. Supported IDs have name and
555 * length fields set, so that we can allocated and use
556 * them. We can safely just check for name, for without the
557 * name, we can't allocate the TFM.
558 */
Dan Rosenberg51e97a12010-10-01 11:51:47 +0000559 if (!sctp_hmac_list[id].hmac_name) {
560 id = 0;
Vlad Yasevich1f485642007-10-09 01:15:59 -0700561 continue;
Dan Rosenberg51e97a12010-10-01 11:51:47 +0000562 }
Vlad Yasevich1f485642007-10-09 01:15:59 -0700563
564 break;
565 }
566
567 if (id == 0)
568 return NULL;
569
570 return &sctp_hmac_list[id];
571}
572
Al Virod06f6082007-10-29 05:03:23 +0000573static int __sctp_auth_find_hmacid(__be16 *hmacs, int n_elts, __be16 hmac_id)
Vlad Yasevich1f485642007-10-09 01:15:59 -0700574{
575 int found = 0;
576 int i;
577
578 for (i = 0; i < n_elts; i++) {
579 if (hmac_id == hmacs[i]) {
580 found = 1;
581 break;
582 }
583 }
584
585 return found;
586}
587
588/* See if the HMAC_ID is one that we claim as supported */
589int sctp_auth_asoc_verify_hmac_id(const struct sctp_association *asoc,
Al Virod06f6082007-10-29 05:03:23 +0000590 __be16 hmac_id)
Vlad Yasevich1f485642007-10-09 01:15:59 -0700591{
592 struct sctp_hmac_algo_param *hmacs;
593 __u16 n_elt;
594
595 if (!asoc)
596 return 0;
597
598 hmacs = (struct sctp_hmac_algo_param *)asoc->c.auth_hmacs;
599 n_elt = (ntohs(hmacs->param_hdr.length) - sizeof(sctp_paramhdr_t)) >> 1;
600
601 return __sctp_auth_find_hmacid(hmacs->hmac_ids, n_elt, hmac_id);
602}
603
604
605/* Cache the default HMAC id. This to follow this text from SCTP-AUTH:
606 * Section 6.1:
607 * The receiver of a HMAC-ALGO parameter SHOULD use the first listed
608 * algorithm it supports.
609 */
610void sctp_auth_asoc_set_default_hmac(struct sctp_association *asoc,
611 struct sctp_hmac_algo_param *hmacs)
612{
613 struct sctp_endpoint *ep;
614 __u16 id;
615 int i;
616 int n_params;
617
618 /* if the default id is already set, use it */
619 if (asoc->default_hmac_id)
620 return;
621
622 n_params = (ntohs(hmacs->param_hdr.length)
623 - sizeof(sctp_paramhdr_t)) >> 1;
624 ep = asoc->ep;
625 for (i = 0; i < n_params; i++) {
626 id = ntohs(hmacs->hmac_ids[i]);
627
628 /* Check the id is in the supported range */
629 if (id > SCTP_AUTH_HMAC_ID_MAX)
630 continue;
631
632 /* If this TFM has been allocated, use this id */
633 if (ep->auth_hmacs[id]) {
634 asoc->default_hmac_id = id;
635 break;
636 }
637 }
638}
639
640
641/* Check to see if the given chunk is supposed to be authenticated */
642static int __sctp_auth_cid(sctp_cid_t chunk, struct sctp_chunks_param *param)
643{
644 unsigned short len;
645 int found = 0;
646 int i;
647
Vlad Yasevich555d3d52007-11-29 08:56:16 -0500648 if (!param || param->param_hdr.length == 0)
Vlad Yasevich1f485642007-10-09 01:15:59 -0700649 return 0;
650
651 len = ntohs(param->param_hdr.length) - sizeof(sctp_paramhdr_t);
652
653 /* SCTP-AUTH, Section 3.2
654 * The chunk types for INIT, INIT-ACK, SHUTDOWN-COMPLETE and AUTH
655 * chunks MUST NOT be listed in the CHUNKS parameter. However, if
656 * a CHUNKS parameter is received then the types for INIT, INIT-ACK,
657 * SHUTDOWN-COMPLETE and AUTH chunks MUST be ignored.
658 */
659 for (i = 0; !found && i < len; i++) {
660 switch (param->chunks[i]) {
661 case SCTP_CID_INIT:
662 case SCTP_CID_INIT_ACK:
663 case SCTP_CID_SHUTDOWN_COMPLETE:
664 case SCTP_CID_AUTH:
665 break;
666
667 default:
668 if (param->chunks[i] == chunk)
669 found = 1;
670 break;
671 }
672 }
673
674 return found;
675}
676
677/* Check if peer requested that this chunk is authenticated */
678int sctp_auth_send_cid(sctp_cid_t chunk, const struct sctp_association *asoc)
679{
Eric W. Biedermane1fc3b12012-08-07 07:29:57 +0000680 struct net *net;
681 if (!asoc)
682 return 0;
683
684 net = sock_net(asoc->base.sk);
685 if (!net->sctp.auth_enable || !asoc->peer.auth_capable)
Vlad Yasevich1f485642007-10-09 01:15:59 -0700686 return 0;
687
688 return __sctp_auth_cid(chunk, asoc->peer.peer_chunks);
689}
690
691/* Check if we requested that peer authenticate this chunk. */
692int sctp_auth_recv_cid(sctp_cid_t chunk, const struct sctp_association *asoc)
693{
Eric W. Biedermane1fc3b12012-08-07 07:29:57 +0000694 struct net *net;
695 if (!asoc)
696 return 0;
697
698 net = sock_net(asoc->base.sk);
Dan Carpenter02644a12012-08-16 03:16:19 +0000699 if (!net->sctp.auth_enable)
Vlad Yasevich1f485642007-10-09 01:15:59 -0700700 return 0;
701
702 return __sctp_auth_cid(chunk,
703 (struct sctp_chunks_param *)asoc->c.auth_chunks);
704}
705
706/* SCTP-AUTH: Section 6.2:
707 * The sender MUST calculate the MAC as described in RFC2104 [2] using
708 * the hash function H as described by the MAC Identifier and the shared
709 * association key K based on the endpoint pair shared key described by
710 * the shared key identifier. The 'data' used for the computation of
711 * the AUTH-chunk is given by the AUTH chunk with its HMAC field set to
712 * zero (as shown in Figure 6) followed by all chunks that are placed
713 * after the AUTH chunk in the SCTP packet.
714 */
715void sctp_auth_calculate_hmac(const struct sctp_association *asoc,
716 struct sk_buff *skb,
717 struct sctp_auth_chunk *auth,
718 gfp_t gfp)
719{
720 struct scatterlist sg;
721 struct hash_desc desc;
722 struct sctp_auth_bytes *asoc_key;
723 __u16 key_id, hmac_id;
724 __u8 *digest;
725 unsigned char *end;
726 int free_key = 0;
727
728 /* Extract the info we need:
729 * - hmac id
730 * - key id
731 */
732 key_id = ntohs(auth->auth_hdr.shkey_id);
733 hmac_id = ntohs(auth->auth_hdr.hmac_id);
734
735 if (key_id == asoc->active_key_id)
736 asoc_key = asoc->asoc_shared_key;
737 else {
738 struct sctp_shared_key *ep_key;
739
740 ep_key = sctp_auth_get_shkey(asoc, key_id);
741 if (!ep_key)
742 return;
743
744 asoc_key = sctp_auth_asoc_create_secret(asoc, ep_key, gfp);
745 if (!asoc_key)
746 return;
747
748 free_key = 1;
749 }
750
751 /* set up scatter list */
752 end = skb_tail_pointer(skb);
Herbert Xu68e3f5d2007-10-27 00:52:07 -0700753 sg_init_one(&sg, auth, end - (unsigned char *)auth);
Vlad Yasevich1f485642007-10-09 01:15:59 -0700754
755 desc.tfm = asoc->ep->auth_hmacs[hmac_id];
756 desc.flags = 0;
757
758 digest = auth->auth_hdr.hmac;
759 if (crypto_hash_setkey(desc.tfm, &asoc_key->data[0], asoc_key->len))
760 goto free;
761
762 crypto_hash_digest(&desc, &sg, sg.length, digest);
763
764free:
765 if (free_key)
766 sctp_auth_key_put(asoc_key);
767}
Vlad Yasevich65b07e52007-09-16 19:34:00 -0700768
769/* API Helpers */
770
771/* Add a chunk to the endpoint authenticated chunk list */
772int sctp_auth_ep_add_chunkid(struct sctp_endpoint *ep, __u8 chunk_id)
773{
774 struct sctp_chunks_param *p = ep->auth_chunk_list;
775 __u16 nchunks;
776 __u16 param_len;
777
778 /* If this chunk is already specified, we are done */
779 if (__sctp_auth_cid(chunk_id, p))
780 return 0;
781
782 /* Check if we can add this chunk to the array */
783 param_len = ntohs(p->param_hdr.length);
784 nchunks = param_len - sizeof(sctp_paramhdr_t);
785 if (nchunks == SCTP_NUM_CHUNK_TYPES)
786 return -EINVAL;
787
788 p->chunks[nchunks] = chunk_id;
789 p->param_hdr.length = htons(param_len + 1);
790 return 0;
791}
792
793/* Add hmac identifires to the endpoint list of supported hmac ids */
794int sctp_auth_ep_set_hmacs(struct sctp_endpoint *ep,
795 struct sctp_hmacalgo *hmacs)
796{
797 int has_sha1 = 0;
798 __u16 id;
799 int i;
800
801 /* Scan the list looking for unsupported id. Also make sure that
802 * SHA1 is specified.
803 */
804 for (i = 0; i < hmacs->shmac_num_idents; i++) {
805 id = hmacs->shmac_idents[i];
806
Vlad Yasevichd9724052008-08-27 16:09:49 -0700807 if (id > SCTP_AUTH_HMAC_ID_MAX)
808 return -EOPNOTSUPP;
809
Vlad Yasevich65b07e52007-09-16 19:34:00 -0700810 if (SCTP_AUTH_HMAC_ID_SHA1 == id)
811 has_sha1 = 1;
812
813 if (!sctp_hmac_list[id].hmac_name)
814 return -EOPNOTSUPP;
815 }
816
817 if (!has_sha1)
818 return -EINVAL;
819
820 memcpy(ep->auth_hmacs_list->hmac_ids, &hmacs->shmac_idents[0],
821 hmacs->shmac_num_idents * sizeof(__u16));
822 ep->auth_hmacs_list->param_hdr.length = htons(sizeof(sctp_paramhdr_t) +
823 hmacs->shmac_num_idents * sizeof(__u16));
824 return 0;
825}
826
827/* Set a new shared key on either endpoint or association. If the
828 * the key with a same ID already exists, replace the key (remove the
829 * old key and add a new one).
830 */
831int sctp_auth_set_key(struct sctp_endpoint *ep,
832 struct sctp_association *asoc,
833 struct sctp_authkey *auth_key)
834{
835 struct sctp_shared_key *cur_key = NULL;
836 struct sctp_auth_bytes *key;
837 struct list_head *sh_keys;
838 int replace = 0;
839
840 /* Try to find the given key id to see if
841 * we are doing a replace, or adding a new key
842 */
843 if (asoc)
844 sh_keys = &asoc->endpoint_shared_keys;
845 else
846 sh_keys = &ep->endpoint_shared_keys;
847
848 key_for_each(cur_key, sh_keys) {
849 if (cur_key->key_id == auth_key->sca_keynumber) {
850 replace = 1;
851 break;
852 }
853 }
854
855 /* If we are not replacing a key id, we need to allocate
856 * a shared key.
857 */
858 if (!replace) {
859 cur_key = sctp_auth_shkey_create(auth_key->sca_keynumber,
860 GFP_KERNEL);
861 if (!cur_key)
862 return -ENOMEM;
863 }
864
865 /* Create a new key data based on the info passed in */
Vlad Yasevich7e8616d2008-02-27 16:04:52 -0500866 key = sctp_auth_create_key(auth_key->sca_keylength, GFP_KERNEL);
Vlad Yasevich65b07e52007-09-16 19:34:00 -0700867 if (!key)
868 goto nomem;
869
Vlad Yasevich7e8616d2008-02-27 16:04:52 -0500870 memcpy(key->data, &auth_key->sca_key[0], auth_key->sca_keylength);
Vlad Yasevich65b07e52007-09-16 19:34:00 -0700871
872 /* If we are replacing, remove the old keys data from the
873 * key id. If we are adding new key id, add it to the
874 * list.
875 */
876 if (replace)
877 sctp_auth_key_put(cur_key->key);
878 else
879 list_add(&cur_key->key_list, sh_keys);
880
881 cur_key->key = key;
882 sctp_auth_key_hold(key);
883
884 return 0;
885nomem:
886 if (!replace)
887 sctp_auth_shkey_free(cur_key);
888
889 return -ENOMEM;
890}
891
892int sctp_auth_set_active_key(struct sctp_endpoint *ep,
893 struct sctp_association *asoc,
894 __u16 key_id)
895{
896 struct sctp_shared_key *key;
897 struct list_head *sh_keys;
898 int found = 0;
899
900 /* The key identifier MUST correst to an existing key */
901 if (asoc)
902 sh_keys = &asoc->endpoint_shared_keys;
903 else
904 sh_keys = &ep->endpoint_shared_keys;
905
906 key_for_each(key, sh_keys) {
907 if (key->key_id == key_id) {
908 found = 1;
909 break;
910 }
911 }
912
913 if (!found)
914 return -EINVAL;
915
916 if (asoc) {
917 asoc->active_key_id = key_id;
918 sctp_auth_asoc_init_active_key(asoc, GFP_KERNEL);
919 } else
920 ep->active_key_id = key_id;
921
922 return 0;
923}
924
925int sctp_auth_del_key_id(struct sctp_endpoint *ep,
926 struct sctp_association *asoc,
927 __u16 key_id)
928{
929 struct sctp_shared_key *key;
930 struct list_head *sh_keys;
931 int found = 0;
932
933 /* The key identifier MUST NOT be the current active key
934 * The key identifier MUST correst to an existing key
935 */
936 if (asoc) {
937 if (asoc->active_key_id == key_id)
938 return -EINVAL;
939
940 sh_keys = &asoc->endpoint_shared_keys;
941 } else {
942 if (ep->active_key_id == key_id)
943 return -EINVAL;
944
945 sh_keys = &ep->endpoint_shared_keys;
946 }
947
948 key_for_each(key, sh_keys) {
949 if (key->key_id == key_id) {
950 found = 1;
951 break;
952 }
953 }
954
955 if (!found)
956 return -EINVAL;
957
958 /* Delete the shared key */
959 list_del_init(&key->key_list);
960 sctp_auth_shkey_free(key);
961
962 return 0;
963}