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[/] [or1k_soc_on_altera_embedded_dev_kit/] [tags/] [linux-2.6/] [linux-2.6.24_or32_unified_v2.3/] [net/] [sctp/] [auth.c] - Blame information for rev 8

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1 3 xianfeng
/* SCTP kernel reference Implementation
2
 * (C) Copyright 2007 Hewlett-Packard Development Company, L.P.
3
 *
4
 * This file is part of the SCTP kernel reference Implementation
5
 *
6
 * The SCTP reference 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
 * The SCTP reference 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, 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
 
37
#include <linux/types.h>
38
#include <linux/crypto.h>
39
#include <linux/scatterlist.h>
40
#include <net/sctp/sctp.h>
41
#include <net/sctp/auth.h>
42
 
43
static struct sctp_hmac sctp_hmac_list[SCTP_AUTH_NUM_HMACS] = {
44
        {
45
                /* id 0 is reserved.  as all 0 */
46
                .hmac_id = SCTP_AUTH_HMAC_ID_RESERVED_0,
47
        },
48
        {
49
                .hmac_id = SCTP_AUTH_HMAC_ID_SHA1,
50
                .hmac_name="hmac(sha1)",
51
                .hmac_len = SCTP_SHA1_SIG_SIZE,
52
        },
53
        {
54
                /* id 2 is reserved as well */
55
                .hmac_id = SCTP_AUTH_HMAC_ID_RESERVED_2,
56
        },
57
#if defined (CONFIG_CRYPTO_SHA256) || defined (CONFIG_CRYPTO_SHA256_MODULE)
58
        {
59
                .hmac_id = SCTP_AUTH_HMAC_ID_SHA256,
60
                .hmac_name="hmac(sha256)",
61
                .hmac_len = SCTP_SHA256_SIG_SIZE,
62
        }
63
#endif
64
};
65
 
66
 
67
void sctp_auth_key_put(struct sctp_auth_bytes *key)
68
{
69
        if (!key)
70
                return;
71
 
72
        if (atomic_dec_and_test(&key->refcnt)) {
73
                kfree(key);
74
                SCTP_DBG_OBJCNT_DEC(keys);
75
        }
76
}
77
 
78
/* Create a new key structure of a given length */
79
static struct sctp_auth_bytes *sctp_auth_create_key(__u32 key_len, gfp_t gfp)
80
{
81
        struct sctp_auth_bytes *key;
82
 
83
        /* Allocate the shared key */
84
        key = kmalloc(sizeof(struct sctp_auth_bytes) + key_len, gfp);
85
        if (!key)
86
                return NULL;
87
 
88
        key->len = key_len;
89
        atomic_set(&key->refcnt, 1);
90
        SCTP_DBG_OBJCNT_INC(keys);
91
 
92
        return key;
93
}
94
 
95
/* Create a new shared key container with a give key id */
96
struct sctp_shared_key *sctp_auth_shkey_create(__u16 key_id, gfp_t gfp)
97
{
98
        struct sctp_shared_key *new;
99
 
100
        /* Allocate the shared key container */
101
        new = kzalloc(sizeof(struct sctp_shared_key), gfp);
102
        if (!new)
103
                return NULL;
104
 
105
        INIT_LIST_HEAD(&new->key_list);
106
        new->key_id = key_id;
107
 
108
        return new;
109
}
110
 
111
/* Free the shared key stucture */
112
static void sctp_auth_shkey_free(struct sctp_shared_key *sh_key)
113
{
114
        BUG_ON(!list_empty(&sh_key->key_list));
115
        sctp_auth_key_put(sh_key->key);
116
        sh_key->key = NULL;
117
        kfree(sh_key);
118
}
119
 
120
/* Destory the entire key list.  This is done during the
121
 * associon and endpoint free process.
122
 */
123
void sctp_auth_destroy_keys(struct list_head *keys)
124
{
125
        struct sctp_shared_key *ep_key;
126
        struct sctp_shared_key *tmp;
127
 
128
        if (list_empty(keys))
129
                return;
130
 
131
        key_for_each_safe(ep_key, tmp, keys) {
132
                list_del_init(&ep_key->key_list);
133
                sctp_auth_shkey_free(ep_key);
134
        }
135
}
136
 
137
/* Compare two byte vectors as numbers.  Return values
138
 * are:
139
 *        0 - vectors are equal
140
 *      < 0 - vector 1 is smaller then vector2
141
 *      > 0 - vector 1 is greater then vector2
142
 *
143
 * Algorithm is:
144
 *      This is performed by selecting the numerically smaller key vector...
145
 *      If the key vectors are equal as numbers but differ in length ...
146
 *      the shorter vector is considered smaller
147
 *
148
 * Examples (with small values):
149
 *      000123456789 > 123456789 (first number is longer)
150
 *      000123456789 < 234567891 (second number is larger numerically)
151
 *      123456789 > 2345678      (first number is both larger & longer)
152
 */
153
static int sctp_auth_compare_vectors(struct sctp_auth_bytes *vector1,
154
                              struct sctp_auth_bytes *vector2)
155
{
156
        int diff;
157
        int i;
158
        const __u8 *longer;
159
 
160
        diff = vector1->len - vector2->len;
161
        if (diff) {
162
                longer = (diff > 0) ? vector1->data : vector2->data;
163
 
164
                /* Check to see if the longer number is
165
                 * lead-zero padded.  If it is not, it
166
                 * is automatically larger numerically.
167
                 */
168
                for (i = 0; i < abs(diff); i++ ) {
169
                        if (longer[i] != 0)
170
                                return diff;
171
                }
172
        }
173
 
174
        /* lengths are the same, compare numbers */
175
        return memcmp(vector1->data, vector2->data, vector1->len);
176
}
177
 
178
/*
179
 * Create a key vector as described in SCTP-AUTH, Section 6.1
180
 *    The RANDOM parameter, the CHUNKS parameter and the HMAC-ALGO
181
 *    parameter sent by each endpoint are concatenated as byte vectors.
182
 *    These parameters include the parameter type, parameter length, and
183
 *    the parameter value, but padding is omitted; all padding MUST be
184
 *    removed from this concatenation before proceeding with further
185
 *    computation of keys.  Parameters which were not sent are simply
186
 *    omitted from the concatenation process.  The resulting two vectors
187
 *    are called the two key vectors.
188
 */
189
static struct sctp_auth_bytes *sctp_auth_make_key_vector(
190
                        sctp_random_param_t *random,
191
                        sctp_chunks_param_t *chunks,
192
                        sctp_hmac_algo_param_t *hmacs,
193
                        gfp_t gfp)
194
{
195
        struct sctp_auth_bytes *new;
196
        __u32   len;
197
        __u32   offset = 0;
198
 
199
        len = ntohs(random->param_hdr.length) + ntohs(hmacs->param_hdr.length);
200
        if (chunks)
201
                len += ntohs(chunks->param_hdr.length);
202
 
203
        new = kmalloc(sizeof(struct sctp_auth_bytes) + len, gfp);
204
        if (!new)
205
                return NULL;
206
 
207
        new->len = len;
208
 
209
        memcpy(new->data, random, ntohs(random->param_hdr.length));
210
        offset += ntohs(random->param_hdr.length);
211
 
212
        if (chunks) {
213
                memcpy(new->data + offset, chunks,
214
                        ntohs(chunks->param_hdr.length));
215
                offset += ntohs(chunks->param_hdr.length);
216
        }
217
 
218
        memcpy(new->data + offset, hmacs, ntohs(hmacs->param_hdr.length));
219
 
220
        return new;
221
}
222
 
223
 
224
/* Make a key vector based on our local parameters */
225
static struct sctp_auth_bytes *sctp_auth_make_local_vector(
226
                                    const struct sctp_association *asoc,
227
                                    gfp_t gfp)
228
{
229
        return sctp_auth_make_key_vector(
230
                                    (sctp_random_param_t*)asoc->c.auth_random,
231
                                    (sctp_chunks_param_t*)asoc->c.auth_chunks,
232
                                    (sctp_hmac_algo_param_t*)asoc->c.auth_hmacs,
233
                                    gfp);
234
}
235
 
236
/* Make a key vector based on peer's parameters */
237
static struct sctp_auth_bytes *sctp_auth_make_peer_vector(
238
                                    const struct sctp_association *asoc,
239
                                    gfp_t gfp)
240
{
241
        return sctp_auth_make_key_vector(asoc->peer.peer_random,
242
                                         asoc->peer.peer_chunks,
243
                                         asoc->peer.peer_hmacs,
244
                                         gfp);
245
}
246
 
247
 
248
/* Set the value of the association shared key base on the parameters
249
 * given.  The algorithm is:
250
 *    From the endpoint pair shared keys and the key vectors the
251
 *    association shared keys are computed.  This is performed by selecting
252
 *    the numerically smaller key vector and concatenating it to the
253
 *    endpoint pair shared key, and then concatenating the numerically
254
 *    larger key vector to that.  The result of the concatenation is the
255
 *    association shared key.
256
 */
257
static struct sctp_auth_bytes *sctp_auth_asoc_set_secret(
258
                        struct sctp_shared_key *ep_key,
259
                        struct sctp_auth_bytes *first_vector,
260
                        struct sctp_auth_bytes *last_vector,
261
                        gfp_t gfp)
262
{
263
        struct sctp_auth_bytes *secret;
264
        __u32 offset = 0;
265
        __u32 auth_len;
266
 
267
        auth_len = first_vector->len + last_vector->len;
268
        if (ep_key->key)
269
                auth_len += ep_key->key->len;
270
 
271
        secret = sctp_auth_create_key(auth_len, gfp);
272
        if (!secret)
273
                return NULL;
274
 
275
        if (ep_key->key) {
276
                memcpy(secret->data, ep_key->key->data, ep_key->key->len);
277
                offset += ep_key->key->len;
278
        }
279
 
280
        memcpy(secret->data + offset, first_vector->data, first_vector->len);
281
        offset += first_vector->len;
282
 
283
        memcpy(secret->data + offset, last_vector->data, last_vector->len);
284
 
285
        return secret;
286
}
287
 
288
/* Create an association shared key.  Follow the algorithm
289
 * described in SCTP-AUTH, Section 6.1
290
 */
291
static struct sctp_auth_bytes *sctp_auth_asoc_create_secret(
292
                                 const struct sctp_association *asoc,
293
                                 struct sctp_shared_key *ep_key,
294
                                 gfp_t gfp)
295
{
296
        struct sctp_auth_bytes *local_key_vector;
297
        struct sctp_auth_bytes *peer_key_vector;
298
        struct sctp_auth_bytes  *first_vector,
299
                                *last_vector;
300
        struct sctp_auth_bytes  *secret = NULL;
301
        int     cmp;
302
 
303
 
304
        /* Now we need to build the key vectors
305
         * SCTP-AUTH , Section 6.1
306
         *    The RANDOM parameter, the CHUNKS parameter and the HMAC-ALGO
307
         *    parameter sent by each endpoint are concatenated as byte vectors.
308
         *    These parameters include the parameter type, parameter length, and
309
         *    the parameter value, but padding is omitted; all padding MUST be
310
         *    removed from this concatenation before proceeding with further
311
         *    computation of keys.  Parameters which were not sent are simply
312
         *    omitted from the concatenation process.  The resulting two vectors
313
         *    are called the two key vectors.
314
         */
315
 
316
        local_key_vector = sctp_auth_make_local_vector(asoc, gfp);
317
        peer_key_vector = sctp_auth_make_peer_vector(asoc, gfp);
318
 
319
        if (!peer_key_vector || !local_key_vector)
320
                goto out;
321
 
322
        /* Figure out the order in wich the key_vectors will be
323
         * added to the endpoint shared key.
324
         * SCTP-AUTH, Section 6.1:
325
         *   This is performed by selecting the numerically smaller key
326
         *   vector and concatenating it to the endpoint pair shared
327
         *   key, and then concatenating the numerically larger key
328
         *   vector to that.  If the key vectors are equal as numbers
329
         *   but differ in length, then the concatenation order is the
330
         *   endpoint shared key, followed by the shorter key vector,
331
         *   followed by the longer key vector.  Otherwise, the key
332
         *   vectors are identical, and may be concatenated to the
333
         *   endpoint pair key in any order.
334
         */
335
        cmp = sctp_auth_compare_vectors(local_key_vector,
336
                                        peer_key_vector);
337
        if (cmp < 0) {
338
                first_vector = local_key_vector;
339
                last_vector = peer_key_vector;
340
        } else {
341
                first_vector = peer_key_vector;
342
                last_vector = local_key_vector;
343
        }
344
 
345
        secret = sctp_auth_asoc_set_secret(ep_key, first_vector, last_vector,
346
                                            gfp);
347
out:
348
        kfree(local_key_vector);
349
        kfree(peer_key_vector);
350
 
351
        return secret;
352
}
353
 
354
/*
355
 * Populate the association overlay list with the list
356
 * from the endpoint.
357
 */
358
int sctp_auth_asoc_copy_shkeys(const struct sctp_endpoint *ep,
359
                                struct sctp_association *asoc,
360
                                gfp_t gfp)
361
{
362
        struct sctp_shared_key *sh_key;
363
        struct sctp_shared_key *new;
364
 
365
        BUG_ON(!list_empty(&asoc->endpoint_shared_keys));
366
 
367
        key_for_each(sh_key, &ep->endpoint_shared_keys) {
368
                new = sctp_auth_shkey_create(sh_key->key_id, gfp);
369
                if (!new)
370
                        goto nomem;
371
 
372
                new->key = sh_key->key;
373
                sctp_auth_key_hold(new->key);
374
                list_add(&new->key_list, &asoc->endpoint_shared_keys);
375
        }
376
 
377
        return 0;
378
 
379
nomem:
380
        sctp_auth_destroy_keys(&asoc->endpoint_shared_keys);
381
        return -ENOMEM;
382
}
383
 
384
 
385
/* Public interface to creat the association shared key.
386
 * See code above for the algorithm.
387
 */
388
int sctp_auth_asoc_init_active_key(struct sctp_association *asoc, gfp_t gfp)
389
{
390
        struct sctp_auth_bytes  *secret;
391
        struct sctp_shared_key *ep_key;
392
 
393
        /* If we don't support AUTH, or peer is not capable
394
         * we don't need to do anything.
395
         */
396
        if (!sctp_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
        return 0;
415
}
416
 
417
 
418
/* Find the endpoint pair shared key based on the key_id */
419
struct sctp_shared_key *sctp_auth_get_shkey(
420
                                const struct sctp_association *asoc,
421
                                __u16 key_id)
422
{
423
        struct sctp_shared_key *key = NULL;
424
 
425
        /* First search associations set of endpoint pair shared keys */
426
        key_for_each(key, &asoc->endpoint_shared_keys) {
427
                if (key->key_id == key_id)
428
                        break;
429
        }
430
 
431
        return key;
432
}
433
 
434
/*
435
 * Initialize all the possible digest transforms that we can use.  Right now
436
 * now, the supported digests are SHA1 and SHA256.  We do this here once
437
 * because of the restrictiong that transforms may only be allocated in
438
 * user context.  This forces us to pre-allocated all possible transforms
439
 * at the endpoint init time.
440
 */
441
int sctp_auth_init_hmacs(struct sctp_endpoint *ep, gfp_t gfp)
442
{
443
        struct crypto_hash *tfm = NULL;
444
        __u16   id;
445
 
446
        /* if the transforms are already allocted, we are done */
447
        if (!sctp_auth_enable) {
448
                ep->auth_hmacs = NULL;
449
                return 0;
450
        }
451
 
452
        if (ep->auth_hmacs)
453
                return 0;
454
 
455
        /* Allocated the array of pointers to transorms */
456
        ep->auth_hmacs = kzalloc(
457
                            sizeof(struct crypto_hash *) * SCTP_AUTH_NUM_HMACS,
458
                            gfp);
459
        if (!ep->auth_hmacs)
460
                return -ENOMEM;
461
 
462
        for (id = 0; id < SCTP_AUTH_NUM_HMACS; id++) {
463
 
464
                /* See is we support the id.  Supported IDs have name and
465
                 * length fields set, so that we can allocated and use
466
                 * them.  We can safely just check for name, for without the
467
                 * name, we can't allocate the TFM.
468
                 */
469
                if (!sctp_hmac_list[id].hmac_name)
470
                        continue;
471
 
472
                /* If this TFM has been allocated, we are all set */
473
                if (ep->auth_hmacs[id])
474
                        continue;
475
 
476
                /* Allocate the ID */
477
                tfm = crypto_alloc_hash(sctp_hmac_list[id].hmac_name, 0,
478
                                        CRYPTO_ALG_ASYNC);
479
                if (IS_ERR(tfm))
480
                        goto out_err;
481
 
482
                ep->auth_hmacs[id] = tfm;
483
        }
484
 
485
        return 0;
486
 
487
out_err:
488
        /* Clean up any successfull allocations */
489
        sctp_auth_destroy_hmacs(ep->auth_hmacs);
490
        return -ENOMEM;
491
}
492
 
493
/* Destroy the hmac tfm array */
494
void sctp_auth_destroy_hmacs(struct crypto_hash *auth_hmacs[])
495
{
496
        int i;
497
 
498
        if (!auth_hmacs)
499
                return;
500
 
501
        for (i = 0; i < SCTP_AUTH_NUM_HMACS; i++)
502
        {
503
                if (auth_hmacs[i])
504
                        crypto_free_hash(auth_hmacs[i]);
505
        }
506
        kfree(auth_hmacs);
507
}
508
 
509
 
510
struct sctp_hmac *sctp_auth_get_hmac(__u16 hmac_id)
511
{
512
        return &sctp_hmac_list[hmac_id];
513
}
514
 
515
/* Get an hmac description information that we can use to build
516
 * the AUTH chunk
517
 */
518
struct sctp_hmac *sctp_auth_asoc_get_hmac(const struct sctp_association *asoc)
519
{
520
        struct sctp_hmac_algo_param *hmacs;
521
        __u16 n_elt;
522
        __u16 id = 0;
523
        int i;
524
 
525
        /* If we have a default entry, use it */
526
        if (asoc->default_hmac_id)
527
                return &sctp_hmac_list[asoc->default_hmac_id];
528
 
529
        /* Since we do not have a default entry, find the first entry
530
         * we support and return that.  Do not cache that id.
531
         */
532
        hmacs = asoc->peer.peer_hmacs;
533
        if (!hmacs)
534
                return NULL;
535
 
536
        n_elt = (ntohs(hmacs->param_hdr.length) - sizeof(sctp_paramhdr_t)) >> 1;
537
        for (i = 0; i < n_elt; i++) {
538
                id = ntohs(hmacs->hmac_ids[i]);
539
 
540
                /* Check the id is in the supported range */
541
                if (id > SCTP_AUTH_HMAC_ID_MAX)
542
                        continue;
543
 
544
                /* See is we support the id.  Supported IDs have name and
545
                 * length fields set, so that we can allocated and use
546
                 * them.  We can safely just check for name, for without the
547
                 * name, we can't allocate the TFM.
548
                 */
549
                if (!sctp_hmac_list[id].hmac_name)
550
                        continue;
551
 
552
                break;
553
        }
554
 
555
        if (id == 0)
556
                return NULL;
557
 
558
        return &sctp_hmac_list[id];
559
}
560
 
561
static int __sctp_auth_find_hmacid(__be16 *hmacs, int n_elts, __be16 hmac_id)
562
{
563
        int  found = 0;
564
        int  i;
565
 
566
        for (i = 0; i < n_elts; i++) {
567
                if (hmac_id == hmacs[i]) {
568
                        found = 1;
569
                        break;
570
                }
571
        }
572
 
573
        return found;
574
}
575
 
576
/* See if the HMAC_ID is one that we claim as supported */
577
int sctp_auth_asoc_verify_hmac_id(const struct sctp_association *asoc,
578
                                    __be16 hmac_id)
579
{
580
        struct sctp_hmac_algo_param *hmacs;
581
        __u16 n_elt;
582
 
583
        if (!asoc)
584
                return 0;
585
 
586
        hmacs = (struct sctp_hmac_algo_param *)asoc->c.auth_hmacs;
587
        n_elt = (ntohs(hmacs->param_hdr.length) - sizeof(sctp_paramhdr_t)) >> 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
 */
598
void sctp_auth_asoc_set_default_hmac(struct sctp_association *asoc,
599
                                     struct sctp_hmac_algo_param *hmacs)
600
{
601
        struct sctp_endpoint *ep;
602
        __u16   id;
603
        int     i;
604
        int     n_params;
605
 
606
        /* if the default id is already set, use it */
607
        if (asoc->default_hmac_id)
608
                return;
609
 
610
        n_params = (ntohs(hmacs->param_hdr.length)
611
                                - sizeof(sctp_paramhdr_t)) >> 1;
612
        ep = asoc->ep;
613
        for (i = 0; i < n_params; i++) {
614
                id = ntohs(hmacs->hmac_ids[i]);
615
 
616
                /* Check the id is in the supported range */
617
                if (id > SCTP_AUTH_HMAC_ID_MAX)
618
                        continue;
619
 
620
                /* If this TFM has been allocated, use this id */
621
                if (ep->auth_hmacs[id]) {
622
                        asoc->default_hmac_id = id;
623
                        break;
624
                }
625
        }
626
}
627
 
628
 
629
/* Check to see if the given chunk is supposed to be authenticated */
630
static int __sctp_auth_cid(sctp_cid_t chunk, struct sctp_chunks_param *param)
631
{
632
        unsigned short len;
633
        int found = 0;
634
        int i;
635
 
636
        if (!param || param->param_hdr.length == 0)
637
                return 0;
638
 
639
        len = ntohs(param->param_hdr.length) - sizeof(sctp_paramhdr_t);
640
 
641
        /* SCTP-AUTH, Section 3.2
642
         *    The chunk types for INIT, INIT-ACK, SHUTDOWN-COMPLETE and AUTH
643
         *    chunks MUST NOT be listed in the CHUNKS parameter.  However, if
644
         *    a CHUNKS parameter is received then the types for INIT, INIT-ACK,
645
         *    SHUTDOWN-COMPLETE and AUTH chunks MUST be ignored.
646
         */
647
        for (i = 0; !found && i < len; i++) {
648
                switch (param->chunks[i]) {
649
                    case SCTP_CID_INIT:
650
                    case SCTP_CID_INIT_ACK:
651
                    case SCTP_CID_SHUTDOWN_COMPLETE:
652
                    case SCTP_CID_AUTH:
653
                        break;
654
 
655
                    default:
656
                        if (param->chunks[i] == chunk)
657
                            found = 1;
658
                        break;
659
                }
660
        }
661
 
662
        return found;
663
}
664
 
665
/* Check if peer requested that this chunk is authenticated */
666
int sctp_auth_send_cid(sctp_cid_t chunk, const struct sctp_association *asoc)
667
{
668
        if (!sctp_auth_enable || !asoc || !asoc->peer.auth_capable)
669
                return 0;
670
 
671
        return __sctp_auth_cid(chunk, asoc->peer.peer_chunks);
672
}
673
 
674
/* Check if we requested that peer authenticate this chunk. */
675
int sctp_auth_recv_cid(sctp_cid_t chunk, const struct sctp_association *asoc)
676
{
677
        if (!sctp_auth_enable || !asoc)
678
                return 0;
679
 
680
        return __sctp_auth_cid(chunk,
681
                              (struct sctp_chunks_param *)asoc->c.auth_chunks);
682
}
683
 
684
/* SCTP-AUTH: Section 6.2:
685
 *    The sender MUST calculate the MAC as described in RFC2104 [2] using
686
 *    the hash function H as described by the MAC Identifier and the shared
687
 *    association key K based on the endpoint pair shared key described by
688
 *    the shared key identifier.  The 'data' used for the computation of
689
 *    the AUTH-chunk is given by the AUTH chunk with its HMAC field set to
690
 *    zero (as shown in Figure 6) followed by all chunks that are placed
691
 *    after the AUTH chunk in the SCTP packet.
692
 */
693
void sctp_auth_calculate_hmac(const struct sctp_association *asoc,
694
                              struct sk_buff *skb,
695
                              struct sctp_auth_chunk *auth,
696
                              gfp_t gfp)
697
{
698
        struct scatterlist sg;
699
        struct hash_desc desc;
700
        struct sctp_auth_bytes *asoc_key;
701
        __u16 key_id, hmac_id;
702
        __u8 *digest;
703
        unsigned char *end;
704
        int free_key = 0;
705
 
706
        /* Extract the info we need:
707
         * - hmac id
708
         * - key id
709
         */
710
        key_id = ntohs(auth->auth_hdr.shkey_id);
711
        hmac_id = ntohs(auth->auth_hdr.hmac_id);
712
 
713
        if (key_id == asoc->active_key_id)
714
                asoc_key = asoc->asoc_shared_key;
715
        else {
716
                struct sctp_shared_key *ep_key;
717
 
718
                ep_key = sctp_auth_get_shkey(asoc, key_id);
719
                if (!ep_key)
720
                        return;
721
 
722
                asoc_key = sctp_auth_asoc_create_secret(asoc, ep_key, gfp);
723
                if (!asoc_key)
724
                        return;
725
 
726
                free_key = 1;
727
        }
728
 
729
        /* set up scatter list */
730
        end = skb_tail_pointer(skb);
731
        sg_init_one(&sg, auth, end - (unsigned char *)auth);
732
 
733
        desc.tfm = asoc->ep->auth_hmacs[hmac_id];
734
        desc.flags = 0;
735
 
736
        digest = auth->auth_hdr.hmac;
737
        if (crypto_hash_setkey(desc.tfm, &asoc_key->data[0], asoc_key->len))
738
                goto free;
739
 
740
        crypto_hash_digest(&desc, &sg, sg.length, digest);
741
 
742
free:
743
        if (free_key)
744
                sctp_auth_key_put(asoc_key);
745
}
746
 
747
/* API Helpers */
748
 
749
/* Add a chunk to the endpoint authenticated chunk list */
750
int sctp_auth_ep_add_chunkid(struct sctp_endpoint *ep, __u8 chunk_id)
751
{
752
        struct sctp_chunks_param *p = ep->auth_chunk_list;
753
        __u16 nchunks;
754
        __u16 param_len;
755
 
756
        /* If this chunk is already specified, we are done */
757
        if (__sctp_auth_cid(chunk_id, p))
758
                return 0;
759
 
760
        /* Check if we can add this chunk to the array */
761
        param_len = ntohs(p->param_hdr.length);
762
        nchunks = param_len - sizeof(sctp_paramhdr_t);
763
        if (nchunks == SCTP_NUM_CHUNK_TYPES)
764
                return -EINVAL;
765
 
766
        p->chunks[nchunks] = chunk_id;
767
        p->param_hdr.length = htons(param_len + 1);
768
        return 0;
769
}
770
 
771
/* Add hmac identifires to the endpoint list of supported hmac ids */
772
int sctp_auth_ep_set_hmacs(struct sctp_endpoint *ep,
773
                           struct sctp_hmacalgo *hmacs)
774
{
775
        int has_sha1 = 0;
776
        __u16 id;
777
        int i;
778
 
779
        /* Scan the list looking for unsupported id.  Also make sure that
780
         * SHA1 is specified.
781
         */
782
        for (i = 0; i < hmacs->shmac_num_idents; i++) {
783
                id = hmacs->shmac_idents[i];
784
 
785
                if (SCTP_AUTH_HMAC_ID_SHA1 == id)
786
                        has_sha1 = 1;
787
 
788
                if (!sctp_hmac_list[id].hmac_name)
789
                        return -EOPNOTSUPP;
790
        }
791
 
792
        if (!has_sha1)
793
                return -EINVAL;
794
 
795
        memcpy(ep->auth_hmacs_list->hmac_ids, &hmacs->shmac_idents[0],
796
                hmacs->shmac_num_idents * sizeof(__u16));
797
        ep->auth_hmacs_list->param_hdr.length = htons(sizeof(sctp_paramhdr_t) +
798
                                hmacs->shmac_num_idents * sizeof(__u16));
799
        return 0;
800
}
801
 
802
/* Set a new shared key on either endpoint or association.  If the
803
 * the key with a same ID already exists, replace the key (remove the
804
 * old key and add a new one).
805
 */
806
int sctp_auth_set_key(struct sctp_endpoint *ep,
807
                      struct sctp_association *asoc,
808
                      struct sctp_authkey *auth_key)
809
{
810
        struct sctp_shared_key *cur_key = NULL;
811
        struct sctp_auth_bytes *key;
812
        struct list_head *sh_keys;
813
        int replace = 0;
814
 
815
        /* Try to find the given key id to see if
816
         * we are doing a replace, or adding a new key
817
         */
818
        if (asoc)
819
                sh_keys = &asoc->endpoint_shared_keys;
820
        else
821
                sh_keys = &ep->endpoint_shared_keys;
822
 
823
        key_for_each(cur_key, sh_keys) {
824
                if (cur_key->key_id == auth_key->sca_keynumber) {
825
                        replace = 1;
826
                        break;
827
                }
828
        }
829
 
830
        /* If we are not replacing a key id, we need to allocate
831
         * a shared key.
832
         */
833
        if (!replace) {
834
                cur_key = sctp_auth_shkey_create(auth_key->sca_keynumber,
835
                                                 GFP_KERNEL);
836
                if (!cur_key)
837
                        return -ENOMEM;
838
        }
839
 
840
        /* Create a new key data based on the info passed in */
841
        key = sctp_auth_create_key(auth_key->sca_keylen, GFP_KERNEL);
842
        if (!key)
843
                goto nomem;
844
 
845
        memcpy(key->data, &auth_key->sca_key[0], auth_key->sca_keylen);
846
 
847
        /* If we are replacing, remove the old keys data from the
848
         * key id.  If we are adding new key id, add it to the
849
         * list.
850
         */
851
        if (replace)
852
                sctp_auth_key_put(cur_key->key);
853
        else
854
                list_add(&cur_key->key_list, sh_keys);
855
 
856
        cur_key->key = key;
857
        sctp_auth_key_hold(key);
858
 
859
        return 0;
860
nomem:
861
        if (!replace)
862
                sctp_auth_shkey_free(cur_key);
863
 
864
        return -ENOMEM;
865
}
866
 
867
int sctp_auth_set_active_key(struct sctp_endpoint *ep,
868
                             struct sctp_association *asoc,
869
                             __u16  key_id)
870
{
871
        struct sctp_shared_key *key;
872
        struct list_head *sh_keys;
873
        int found = 0;
874
 
875
        /* The key identifier MUST correst to an existing key */
876
        if (asoc)
877
                sh_keys = &asoc->endpoint_shared_keys;
878
        else
879
                sh_keys = &ep->endpoint_shared_keys;
880
 
881
        key_for_each(key, sh_keys) {
882
                if (key->key_id == key_id) {
883
                        found = 1;
884
                        break;
885
                }
886
        }
887
 
888
        if (!found)
889
                return -EINVAL;
890
 
891
        if (asoc) {
892
                asoc->active_key_id = key_id;
893
                sctp_auth_asoc_init_active_key(asoc, GFP_KERNEL);
894
        } else
895
                ep->active_key_id = key_id;
896
 
897
        return 0;
898
}
899
 
900
int sctp_auth_del_key_id(struct sctp_endpoint *ep,
901
                         struct sctp_association *asoc,
902
                         __u16  key_id)
903
{
904
        struct sctp_shared_key *key;
905
        struct list_head *sh_keys;
906
        int found = 0;
907
 
908
        /* The key identifier MUST NOT be the current active key
909
         * The key identifier MUST correst to an existing key
910
         */
911
        if (asoc) {
912
                if (asoc->active_key_id == key_id)
913
                        return -EINVAL;
914
 
915
                sh_keys = &asoc->endpoint_shared_keys;
916
        } else {
917
                if (ep->active_key_id == key_id)
918
                        return -EINVAL;
919
 
920
                sh_keys = &ep->endpoint_shared_keys;
921
        }
922
 
923
        key_for_each(key, sh_keys) {
924
                if (key->key_id == key_id) {
925
                        found = 1;
926
                        break;
927
                }
928
        }
929
 
930
        if (!found)
931
                return -EINVAL;
932
 
933
        /* Delete the shared key */
934
        list_del_init(&key->key_list);
935
        sctp_auth_shkey_free(key);
936
 
937
        return 0;
938
}

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