root/net/sctp/auth.c

DEFINITIONS

1. sctp_auth_key_put
2. sctp_auth_create_key
3. sctp_auth_shkey_create
4. sctp_auth_shkey_destroy
5. sctp_auth_shkey_release
6. sctp_auth_shkey_hold
7. sctp_auth_destroy_keys
8. sctp_auth_compare_vectors
9. sctp_auth_make_key_vector
10. sctp_auth_make_local_vector
11. sctp_auth_make_peer_vector
12. sctp_auth_asoc_set_secret
13. sctp_auth_asoc_create_secret
14. sctp_auth_asoc_copy_shkeys
15. sctp_auth_asoc_init_active_key
16. sctp_auth_get_shkey
17. sctp_auth_init_hmacs
18. sctp_auth_destroy_hmacs
19. sctp_auth_get_hmac
20. sctp_auth_asoc_get_hmac
21. __sctp_auth_find_hmacid
22. sctp_auth_asoc_verify_hmac_id
23. sctp_auth_asoc_set_default_hmac
24. __sctp_auth_cid
25. sctp_auth_send_cid
26. sctp_auth_recv_cid
27. sctp_auth_calculate_hmac
28. sctp_auth_ep_add_chunkid
29. sctp_auth_ep_set_hmacs
30. sctp_auth_set_key
31. sctp_auth_set_active_key
32. sctp_auth_del_key_id
33. sctp_auth_deact_key_id
34. sctp_auth_init
35. sctp_auth_free

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /* SCTP kernel implementation
   3  * (C) Copyright 2007 Hewlett-Packard Development Company, L.P.
   4  *
   5  * This file is part of the SCTP kernel implementation
   6  *
   7  * Please send any bug reports or fixes you make to the
   8  * email address(es):
   9  *    lksctp developers <linux-sctp@vger.kernel.org>
  10  *
  11  * Written or modified by:
  12  *   Vlad Yasevich     <vladislav.yasevich@hp.com>
  13  */
  14 
  15 #include <crypto/hash.h>
  16 #include <linux/slab.h>
  17 #include <linux/types.h>
  18 #include <linux/scatterlist.h>
  19 #include <net/sctp/sctp.h>
  20 #include <net/sctp/auth.h>
  21 
  22 static struct sctp_hmac sctp_hmac_list[SCTP_AUTH_NUM_HMACS] = {
  23         {
  24                 /* id 0 is reserved.  as all 0 */
  25                 .hmac_id = SCTP_AUTH_HMAC_ID_RESERVED_0,
  26         },
  27         {
  28                 .hmac_id = SCTP_AUTH_HMAC_ID_SHA1,
  29                 .hmac_name = "hmac(sha1)",
  30                 .hmac_len = SCTP_SHA1_SIG_SIZE,
  31         },
  32         {
  33                 /* id 2 is reserved as well */
  34                 .hmac_id = SCTP_AUTH_HMAC_ID_RESERVED_2,
  35         },
  36 #if IS_ENABLED(CONFIG_CRYPTO_SHA256)
  37         {
  38                 .hmac_id = SCTP_AUTH_HMAC_ID_SHA256,
  39                 .hmac_name = "hmac(sha256)",
  40                 .hmac_len = SCTP_SHA256_SIG_SIZE,
  41         }
  42 #endif
  43 };
  44 
  45 
  46 void sctp_auth_key_put(struct sctp_auth_bytes *key)
  47 {
  48         if (!key)
  49                 return;
  50 
  51         if (refcount_dec_and_test(&key->refcnt)) {
  52                 kzfree(key);
  53                 SCTP_DBG_OBJCNT_DEC(keys);
  54         }
  55 }
  56 
  57 /* Create a new key structure of a given length */
  58 static struct sctp_auth_bytes *sctp_auth_create_key(__u32 key_len, gfp_t gfp)
  59 {
  60         struct sctp_auth_bytes *key;
  61 
  62         /* Verify that we are not going to overflow INT_MAX */
  63         if (key_len > (INT_MAX - sizeof(struct sctp_auth_bytes)))
  64                 return NULL;
  65 
  66         /* Allocate the shared key */
  67         key = kmalloc(sizeof(struct sctp_auth_bytes) + key_len, gfp);
  68         if (!key)
  69                 return NULL;
  70 
  71         key->len = key_len;
  72         refcount_set(&key->refcnt, 1);
  73         SCTP_DBG_OBJCNT_INC(keys);
  74 
  75         return key;
  76 }
  77 
  78 /* Create a new shared key container with a give key id */
  79 struct sctp_shared_key *sctp_auth_shkey_create(__u16 key_id, gfp_t gfp)
  80 {
  81         struct sctp_shared_key *new;
  82 
  83         /* Allocate the shared key container */
  84         new = kzalloc(sizeof(struct sctp_shared_key), gfp);
  85         if (!new)
  86                 return NULL;
  87 
  88         INIT_LIST_HEAD(&new->key_list);
  89         refcount_set(&new->refcnt, 1);
  90         new->key_id = key_id;
  91 
  92         return new;
  93 }
  94 
  95 /* Free the shared key structure */
  96 static void sctp_auth_shkey_destroy(struct sctp_shared_key *sh_key)
  97 {
  98         BUG_ON(!list_empty(&sh_key->key_list));
  99         sctp_auth_key_put(sh_key->key);
 100         sh_key->key = NULL;
 101         kfree(sh_key);
 102 }
 103 
 104 void sctp_auth_shkey_release(struct sctp_shared_key *sh_key)
 105 {
 106         if (refcount_dec_and_test(&sh_key->refcnt))
 107                 sctp_auth_shkey_destroy(sh_key);
 108 }
 109 
 110 void sctp_auth_shkey_hold(struct sctp_shared_key *sh_key)
 111 {
 112         refcount_inc(&sh_key->refcnt);
 113 }
 114 
 115 /* Destroy the entire key list.  This is done during the
 116  * associon and endpoint free process.
 117  */
 118 void sctp_auth_destroy_keys(struct list_head *keys)
 119 {
 120         struct sctp_shared_key *ep_key;
 121         struct sctp_shared_key *tmp;
 122 
 123         if (list_empty(keys))
 124                 return;
 125 
 126         key_for_each_safe(ep_key, tmp, keys) {
 127                 list_del_init(&ep_key->key_list);
 128                 sctp_auth_shkey_release(ep_key);
 129         }
 130 }
 131 
 132 /* Compare two byte vectors as numbers.  Return values
 133  * are:
 134  *        0 - vectors are equal
 135  *      < 0 - vector 1 is smaller than vector2
 136  *      > 0 - vector 1 is greater than vector2
 137  *
 138  * Algorithm is:
 139  *      This is performed by selecting the numerically smaller key vector...
 140  *      If the key vectors are equal as numbers but differ in length ...
 141  *      the shorter vector is considered smaller
 142  *
 143  * Examples (with small values):
 144  *      000123456789 > 123456789 (first number is longer)
 145  *      000123456789 < 234567891 (second number is larger numerically)
 146  *      123456789 > 2345678      (first number is both larger & longer)
 147  */
 148 static int sctp_auth_compare_vectors(struct sctp_auth_bytes *vector1,
 149                               struct sctp_auth_bytes *vector2)
 150 {
 151         int diff;
 152         int i;
 153         const __u8 *longer;
 154 
 155         diff = vector1->len - vector2->len;
 156         if (diff) {
 157                 longer = (diff > 0) ? vector1->data : vector2->data;
 158 
 159                 /* Check to see if the longer number is
 160                  * lead-zero padded.  If it is not, it
 161                  * is automatically larger numerically.
 162                  */
 163                 for (i = 0; i < abs(diff); i++) {
 164                         if (longer[i] != 0)
 165                                 return diff;
 166                 }
 167         }
 168 
 169         /* lengths are the same, compare numbers */
 170         return memcmp(vector1->data, vector2->data, vector1->len);
 171 }
 172 
 173 /*
 174  * Create a key vector as described in SCTP-AUTH, Section 6.1
 175  *    The RANDOM parameter, the CHUNKS parameter and the HMAC-ALGO
 176  *    parameter sent by each endpoint are concatenated as byte vectors.
 177  *    These parameters include the parameter type, parameter length, and
 178  *    the parameter value, but padding is omitted; all padding MUST be
 179  *    removed from this concatenation before proceeding with further
 180  *    computation of keys.  Parameters which were not sent are simply
 181  *    omitted from the concatenation process.  The resulting two vectors
 182  *    are called the two key vectors.
 183  */
 184 static struct sctp_auth_bytes *sctp_auth_make_key_vector(
 185                         struct sctp_random_param *random,
 186                         struct sctp_chunks_param *chunks,
 187                         struct sctp_hmac_algo_param *hmacs,
 188                         gfp_t gfp)
 189 {
 190         struct sctp_auth_bytes *new;
 191         __u32   len;
 192         __u32   offset = 0;
 193         __u16   random_len, hmacs_len, chunks_len = 0;
 194 
 195         random_len = ntohs(random->param_hdr.length);
 196         hmacs_len = ntohs(hmacs->param_hdr.length);
 197         if (chunks)
 198                 chunks_len = ntohs(chunks->param_hdr.length);
 199 
 200         len = random_len + hmacs_len + chunks_len;
 201 
 202         new = sctp_auth_create_key(len, gfp);
 203         if (!new)
 204                 return NULL;
 205 
 206         memcpy(new->data, random, random_len);
 207         offset += random_len;
 208 
 209         if (chunks) {
 210                 memcpy(new->data + offset, chunks, chunks_len);
 211                 offset += chunks_len;
 212         }
 213 
 214         memcpy(new->data + offset, hmacs, hmacs_len);
 215 
 216         return new;
 217 }
 218 
 219 
 220 /* Make a key vector based on our local parameters */
 221 static struct sctp_auth_bytes *sctp_auth_make_local_vector(
 222                                     const struct sctp_association *asoc,
 223                                     gfp_t gfp)
 224 {
 225         return sctp_auth_make_key_vector(
 226                         (struct sctp_random_param *)asoc->c.auth_random,
 227                         (struct sctp_chunks_param *)asoc->c.auth_chunks,
 228                         (struct sctp_hmac_algo_param *)asoc->c.auth_hmacs, gfp);
 229 }
 230 
 231 /* Make a key vector based on peer's parameters */
 232 static struct sctp_auth_bytes *sctp_auth_make_peer_vector(
 233                                     const struct sctp_association *asoc,
 234                                     gfp_t gfp)
 235 {
 236         return sctp_auth_make_key_vector(asoc->peer.peer_random,
 237                                          asoc->peer.peer_chunks,
 238                                          asoc->peer.peer_hmacs,
 239                                          gfp);
 240 }
 241 
 242 
 243 /* Set the value of the association shared key base on the parameters
 244  * given.  The algorithm is:
 245  *    From the endpoint pair shared keys and the key vectors the
 246  *    association shared keys are computed.  This is performed by selecting
 247  *    the numerically smaller key vector and concatenating it to the
 248  *    endpoint pair shared key, and then concatenating the numerically
 249  *    larger key vector to that.  The result of the concatenation is the
 250  *    association shared key.
 251  */
 252 static struct sctp_auth_bytes *sctp_auth_asoc_set_secret(
 253                         struct sctp_shared_key *ep_key,
 254                         struct sctp_auth_bytes *first_vector,
 255                         struct sctp_auth_bytes *last_vector,
 256                         gfp_t gfp)
 257 {
 258         struct sctp_auth_bytes *secret;
 259         __u32 offset = 0;
 260         __u32 auth_len;
 261 
 262         auth_len = first_vector->len + last_vector->len;
 263         if (ep_key->key)
 264                 auth_len += ep_key->key->len;
 265 
 266         secret = sctp_auth_create_key(auth_len, gfp);
 267         if (!secret)
 268                 return NULL;
 269 
 270         if (ep_key->key) {
 271                 memcpy(secret->data, ep_key->key->data, ep_key->key->len);
 272                 offset += ep_key->key->len;
 273         }
 274 
 275         memcpy(secret->data + offset, first_vector->data, first_vector->len);
 276         offset += first_vector->len;
 277 
 278         memcpy(secret->data + offset, last_vector->data, last_vector->len);
 279 
 280         return secret;
 281 }
 282 
 283 /* Create an association shared key.  Follow the algorithm
 284  * described in SCTP-AUTH, Section 6.1
 285  */
 286 static struct sctp_auth_bytes *sctp_auth_asoc_create_secret(
 287                                  const struct sctp_association *asoc,
 288                                  struct sctp_shared_key *ep_key,
 289                                  gfp_t gfp)
 290 {
 291         struct sctp_auth_bytes *local_key_vector;
 292         struct sctp_auth_bytes *peer_key_vector;
 293         struct sctp_auth_bytes  *first_vector,
 294                                 *last_vector;
 295         struct sctp_auth_bytes  *secret = NULL;
 296         int     cmp;
 297 
 298 
 299         /* Now we need to build the key vectors
 300          * SCTP-AUTH , Section 6.1
 301          *    The RANDOM parameter, the CHUNKS parameter and the HMAC-ALGO
 302          *    parameter sent by each endpoint are concatenated as byte vectors.
 303          *    These parameters include the parameter type, parameter length, and
 304          *    the parameter value, but padding is omitted; all padding MUST be
 305          *    removed from this concatenation before proceeding with further
 306          *    computation of keys.  Parameters which were not sent are simply
 307          *    omitted from the concatenation process.  The resulting two vectors
 308          *    are called the two key vectors.
 309          */
 310 
 311         local_key_vector = sctp_auth_make_local_vector(asoc, gfp);
 312         peer_key_vector = sctp_auth_make_peer_vector(asoc, gfp);
 313 
 314         if (!peer_key_vector || !local_key_vector)
 315                 goto out;
 316 
 317         /* Figure out the order in which the key_vectors will be
 318          * added to the endpoint shared key.
 319          * SCTP-AUTH, Section 6.1:
 320          *   This is performed by selecting the numerically smaller key
 321          *   vector and concatenating it to the endpoint pair shared
 322          *   key, and then concatenating the numerically larger key
 323          *   vector to that.  If the key vectors are equal as numbers
 324          *   but differ in length, then the concatenation order is the
 325          *   endpoint shared key, followed by the shorter key vector,
 326          *   followed by the longer key vector.  Otherwise, the key
 327          *   vectors are identical, and may be concatenated to the
 328          *   endpoint pair key in any order.
 329          */
 330         cmp = sctp_auth_compare_vectors(local_key_vector,
 331                                         peer_key_vector);
 332         if (cmp < 0) {
 333                 first_vector = local_key_vector;
 334                 last_vector = peer_key_vector;
 335         } else {
 336                 first_vector = peer_key_vector;
 337                 last_vector = local_key_vector;
 338         }
 339 
 340         secret = sctp_auth_asoc_set_secret(ep_key, first_vector, last_vector,
 341                                             gfp);
 342 out:
 343         sctp_auth_key_put(local_key_vector);
 344         sctp_auth_key_put(peer_key_vector);
 345 
 346         return secret;
 347 }
 348 
 349 /*
 350  * Populate the association overlay list with the list
 351  * from the endpoint.
 352  */
 353 int sctp_auth_asoc_copy_shkeys(const struct sctp_endpoint *ep,
 354                                 struct sctp_association *asoc,
 355                                 gfp_t gfp)
 356 {
 357         struct sctp_shared_key *sh_key;
 358         struct sctp_shared_key *new;
 359 
 360         BUG_ON(!list_empty(&asoc->endpoint_shared_keys));
 361 
 362         key_for_each(sh_key, &ep->endpoint_shared_keys) {
 363                 new = sctp_auth_shkey_create(sh_key->key_id, gfp);
 364                 if (!new)
 365                         goto nomem;
 366 
 367                 new->key = sh_key->key;
 368                 sctp_auth_key_hold(new->key);
 369                 list_add(&new->key_list, &asoc->endpoint_shared_keys);
 370         }
 371 
 372         return 0;
 373 
 374 nomem:
 375         sctp_auth_destroy_keys(&asoc->endpoint_shared_keys);
 376         return -ENOMEM;
 377 }
 378 
 379 
 380 /* Public interface to create the association shared key.
 381  * See code above for the algorithm.
 382  */
 383 int sctp_auth_asoc_init_active_key(struct sctp_association *asoc, gfp_t gfp)
 384 {
 385         struct sctp_auth_bytes  *secret;
 386         struct sctp_shared_key *ep_key;
 387         struct sctp_chunk *chunk;
 388 
 389         /* If we don't support AUTH, or peer is not capable
 390          * we don't need to do anything.
 391          */
 392         if (!asoc->peer.auth_capable)
 393                 return 0;
 394 
 395         /* If the key_id is non-zero and we couldn't find an
 396          * endpoint pair shared key, we can't compute the
 397          * secret.
 398          * For key_id 0, endpoint pair shared key is a NULL key.
 399          */
 400         ep_key = sctp_auth_get_shkey(asoc, asoc->active_key_id);
 401         BUG_ON(!ep_key);
 402 
 403         secret = sctp_auth_asoc_create_secret(asoc, ep_key, gfp);
 404         if (!secret)
 405                 return -ENOMEM;
 406 
 407         sctp_auth_key_put(asoc->asoc_shared_key);
 408         asoc->asoc_shared_key = secret;
 409         asoc->shkey = ep_key;
 410 
 411         /* Update send queue in case any chunk already in there now
 412          * needs authenticating
 413          */
 414         list_for_each_entry(chunk, &asoc->outqueue.out_chunk_list, list) {
 415                 if (sctp_auth_send_cid(chunk->chunk_hdr->type, asoc)) {
 416                         chunk->auth = 1;
 417                         if (!chunk->shkey) {
 418                                 chunk->shkey = asoc->shkey;
 419                                 sctp_auth_shkey_hold(chunk->shkey);
 420                         }
 421                 }
 422         }
 423 
 424         return 0;
 425 }
 426 
 427 
 428 /* Find the endpoint pair shared key based on the key_id */
 429 struct sctp_shared_key *sctp_auth_get_shkey(
 430                                 const struct sctp_association *asoc,
 431                                 __u16 key_id)
 432 {
 433         struct sctp_shared_key *key;
 434 
 435         /* First search associations set of endpoint pair shared keys */
 436         key_for_each(key, &asoc->endpoint_shared_keys) {
 437                 if (key->key_id == key_id) {
 438                         if (!key->deactivated)
 439                                 return key;
 440                         break;
 441                 }
 442         }
 443 
 444         return NULL;
 445 }
 446 
 447 /*
 448  * Initialize all the possible digest transforms that we can use.  Right now
 449  * now, the supported digests are SHA1 and SHA256.  We do this here once
 450  * because of the restrictiong that transforms may only be allocated in
 451  * user context.  This forces us to pre-allocated all possible transforms
 452  * at the endpoint init time.
 453  */
 454 int sctp_auth_init_hmacs(struct sctp_endpoint *ep, gfp_t gfp)
 455 {
 456         struct crypto_shash *tfm = NULL;
 457         __u16   id;
 458 
 459         /* If the transforms are already allocated, we are done */
 460         if (ep->auth_hmacs)
 461                 return 0;
 462 
 463         /* Allocated the array of pointers to transorms */
 464         ep->auth_hmacs = kcalloc(SCTP_AUTH_NUM_HMACS,
 465                                  sizeof(struct crypto_shash *),
 466                                  gfp);
 467         if (!ep->auth_hmacs)
 468                 return -ENOMEM;
 469 
 470         for (id = 0; id < SCTP_AUTH_NUM_HMACS; id++) {
 471 
 472                 /* See is we support the id.  Supported IDs have name and
 473                  * length fields set, so that we can allocated and use
 474                  * them.  We can safely just check for name, for without the
 475                  * name, we can't allocate the TFM.
 476                  */
 477                 if (!sctp_hmac_list[id].hmac_name)
 478                         continue;
 479 
 480                 /* If this TFM has been allocated, we are all set */
 481                 if (ep->auth_hmacs[id])
 482                         continue;
 483 
 484                 /* Allocate the ID */
 485                 tfm = crypto_alloc_shash(sctp_hmac_list[id].hmac_name, 0, 0);
 486                 if (IS_ERR(tfm))
 487                         goto out_err;
 488 
 489                 ep->auth_hmacs[id] = tfm;
 490         }
 491 
 492         return 0;
 493 
 494 out_err:
 495         /* Clean up any successful allocations */
 496         sctp_auth_destroy_hmacs(ep->auth_hmacs);
 497         return -ENOMEM;
 498 }
 499 
 500 /* Destroy the hmac tfm array */
 501 void sctp_auth_destroy_hmacs(struct crypto_shash *auth_hmacs[])
 502 {
 503         int i;
 504 
 505         if (!auth_hmacs)
 506                 return;
 507 
 508         for (i = 0; i < SCTP_AUTH_NUM_HMACS; i++) {
 509                 crypto_free_shash(auth_hmacs[i]);
 510         }
 511         kfree(auth_hmacs);
 512 }
 513 
 514 
 515 struct sctp_hmac *sctp_auth_get_hmac(__u16 hmac_id)
 516 {
 517         return &sctp_hmac_list[hmac_id];
 518 }
 519 
 520 /* Get an hmac description information that we can use to build
 521  * the AUTH chunk
 522  */
 523 struct sctp_hmac *sctp_auth_asoc_get_hmac(const struct sctp_association *asoc)
 524 {
 525         struct sctp_hmac_algo_param *hmacs;
 526         __u16 n_elt;
 527         __u16 id = 0;
 528         int i;
 529 
 530         /* If we have a default entry, use it */
 531         if (asoc->default_hmac_id)
 532                 return &sctp_hmac_list[asoc->default_hmac_id];
 533 
 534         /* Since we do not have a default entry, find the first entry
 535          * we support and return that.  Do not cache that id.
 536          */
 537         hmacs = asoc->peer.peer_hmacs;
 538         if (!hmacs)
 539                 return NULL;
 540 
 541         n_elt = (ntohs(hmacs->param_hdr.length) -
 542                  sizeof(struct sctp_paramhdr)) >> 1;
 543         for (i = 0; i < n_elt; i++) {
 544                 id = ntohs(hmacs->hmac_ids[i]);
 545 
 546                 /* Check the id is in the supported range. And
 547                  * see if we support the id.  Supported IDs have name and
 548                  * length fields set, so that we can allocate and use
 549                  * them.  We can safely just check for name, for without the
 550                  * name, we can't allocate the TFM.
 551                  */
 552                 if (id > SCTP_AUTH_HMAC_ID_MAX ||
 553                     !sctp_hmac_list[id].hmac_name) {
 554                         id = 0;
 555                         continue;
 556                 }
 557 
 558                 break;
 559         }
 560 
 561         if (id == 0)
 562                 return NULL;
 563 
 564         return &sctp_hmac_list[id];
 565 }
 566 
 567 static int __sctp_auth_find_hmacid(__be16 *hmacs, int n_elts, __be16 hmac_id)
 568 {
 569         int  found = 0;
 570         int  i;
 571 
 572         for (i = 0; i < n_elts; i++) {
 573                 if (hmac_id == hmacs[i]) {
 574                         found = 1;
 575                         break;
 576                 }
 577         }
 578 
 579         return found;
 580 }
 581 
 582 /* See if the HMAC_ID is one that we claim as supported */
 583 int sctp_auth_asoc_verify_hmac_id(const struct sctp_association *asoc,
 584                                     __be16 hmac_id)
 585 {
 586         struct sctp_hmac_algo_param *hmacs;
 587         __u16 n_elt;
 588 
 589         if (!asoc)
 590                 return 0;
 591 
 592         hmacs = (struct sctp_hmac_algo_param *)asoc->c.auth_hmacs;
 593         n_elt = (ntohs(hmacs->param_hdr.length) -
 594                  sizeof(struct sctp_paramhdr)) >> 1;
 595 
 596         return __sctp_auth_find_hmacid(hmacs->hmac_ids, n_elt, hmac_id);
 597 }
 598 
 599 
 600 /* Cache the default HMAC id.  This to follow this text from SCTP-AUTH:
 601  * Section 6.1:
 602  *   The receiver of a HMAC-ALGO parameter SHOULD use the first listed
 603  *   algorithm it supports.
 604  */
 605 void sctp_auth_asoc_set_default_hmac(struct sctp_association *asoc,
 606                                      struct sctp_hmac_algo_param *hmacs)
 607 {
 608         struct sctp_endpoint *ep;
 609         __u16   id;
 610         int     i;
 611         int     n_params;
 612 
 613         /* if the default id is already set, use it */
 614         if (asoc->default_hmac_id)
 615                 return;
 616 
 617         n_params = (ntohs(hmacs->param_hdr.length) -
 618                     sizeof(struct sctp_paramhdr)) >> 1;
 619         ep = asoc->ep;
 620         for (i = 0; i < n_params; i++) {
 621                 id = ntohs(hmacs->hmac_ids[i]);
 622 
 623                 /* Check the id is in the supported range */
 624                 if (id > SCTP_AUTH_HMAC_ID_MAX)
 625                         continue;
 626 
 627                 /* If this TFM has been allocated, use this id */
 628                 if (ep->auth_hmacs[id]) {
 629                         asoc->default_hmac_id = id;
 630                         break;
 631                 }
 632         }
 633 }
 634 
 635 
 636 /* Check to see if the given chunk is supposed to be authenticated */
 637 static int __sctp_auth_cid(enum sctp_cid chunk, struct sctp_chunks_param *param)
 638 {
 639         unsigned short len;
 640         int found = 0;
 641         int i;
 642 
 643         if (!param || param->param_hdr.length == 0)
 644                 return 0;
 645 
 646         len = ntohs(param->param_hdr.length) - sizeof(struct sctp_paramhdr);
 647 
 648         /* SCTP-AUTH, Section 3.2
 649          *    The chunk types for INIT, INIT-ACK, SHUTDOWN-COMPLETE and AUTH
 650          *    chunks MUST NOT be listed in the CHUNKS parameter.  However, if
 651          *    a CHUNKS parameter is received then the types for INIT, INIT-ACK,
 652          *    SHUTDOWN-COMPLETE and AUTH chunks MUST be ignored.
 653          */
 654         for (i = 0; !found && i < len; i++) {
 655                 switch (param->chunks[i]) {
 656                 case SCTP_CID_INIT:
 657                 case SCTP_CID_INIT_ACK:
 658                 case SCTP_CID_SHUTDOWN_COMPLETE:
 659                 case SCTP_CID_AUTH:
 660                         break;
 661 
 662                 default:
 663                         if (param->chunks[i] == chunk)
 664                                 found = 1;
 665                         break;
 666                 }
 667         }
 668 
 669         return found;
 670 }
 671 
 672 /* Check if peer requested that this chunk is authenticated */
 673 int sctp_auth_send_cid(enum sctp_cid chunk, const struct sctp_association *asoc)
 674 {
 675         if (!asoc)
 676                 return 0;
 677 
 678         if (!asoc->peer.auth_capable)
 679                 return 0;
 680 
 681         return __sctp_auth_cid(chunk, asoc->peer.peer_chunks);
 682 }
 683 
 684 /* Check if we requested that peer authenticate this chunk. */
 685 int sctp_auth_recv_cid(enum sctp_cid chunk, const struct sctp_association *asoc)
 686 {
 687         if (!asoc)
 688                 return 0;
 689 
 690         if (!asoc->peer.auth_capable)
 691                 return 0;
 692 
 693         return __sctp_auth_cid(chunk,
 694                               (struct sctp_chunks_param *)asoc->c.auth_chunks);
 695 }
 696 
 697 /* SCTP-AUTH: Section 6.2:
 698  *    The sender MUST calculate the MAC as described in RFC2104 [2] using
 699  *    the hash function H as described by the MAC Identifier and the shared
 700  *    association key K based on the endpoint pair shared key described by
 701  *    the shared key identifier.  The 'data' used for the computation of
 702  *    the AUTH-chunk is given by the AUTH chunk with its HMAC field set to
 703  *    zero (as shown in Figure 6) followed by all chunks that are placed
 704  *    after the AUTH chunk in the SCTP packet.
 705  */
 706 void sctp_auth_calculate_hmac(const struct sctp_association *asoc,
 707                               struct sk_buff *skb, struct sctp_auth_chunk *auth,
 708                               struct sctp_shared_key *ep_key, gfp_t gfp)
 709 {
 710         struct sctp_auth_bytes *asoc_key;
 711         struct crypto_shash *tfm;
 712         __u16 key_id, hmac_id;
 713         unsigned char *end;
 714         int free_key = 0;
 715         __u8 *digest;
 716 
 717         /* Extract the info we need:
 718          * - hmac id
 719          * - key id
 720          */
 721         key_id = ntohs(auth->auth_hdr.shkey_id);
 722         hmac_id = ntohs(auth->auth_hdr.hmac_id);
 723 
 724         if (key_id == asoc->active_key_id)
 725                 asoc_key = asoc->asoc_shared_key;
 726         else {
 727                 /* ep_key can't be NULL here */
 728                 asoc_key = sctp_auth_asoc_create_secret(asoc, ep_key, gfp);
 729                 if (!asoc_key)
 730                         return;
 731 
 732                 free_key = 1;
 733         }
 734 
 735         /* set up scatter list */
 736         end = skb_tail_pointer(skb);
 737 
 738         tfm = asoc->ep->auth_hmacs[hmac_id];
 739 
 740         digest = auth->auth_hdr.hmac;
 741         if (crypto_shash_setkey(tfm, &asoc_key->data[0], asoc_key->len))
 742                 goto free;
 743 
 744         {
 745                 SHASH_DESC_ON_STACK(desc, tfm);
 746 
 747                 desc->tfm = tfm;
 748                 crypto_shash_digest(desc, (u8 *)auth,
 749                                     end - (unsigned char *)auth, digest);
 750                 shash_desc_zero(desc);
 751         }
 752 
 753 free:
 754         if (free_key)
 755                 sctp_auth_key_put(asoc_key);
 756 }
 757 
 758 /* API Helpers */
 759 
 760 /* Add a chunk to the endpoint authenticated chunk list */
 761 int sctp_auth_ep_add_chunkid(struct sctp_endpoint *ep, __u8 chunk_id)
 762 {
 763         struct sctp_chunks_param *p = ep->auth_chunk_list;
 764         __u16 nchunks;
 765         __u16 param_len;
 766 
 767         /* If this chunk is already specified, we are done */
 768         if (__sctp_auth_cid(chunk_id, p))
 769                 return 0;
 770 
 771         /* Check if we can add this chunk to the array */
 772         param_len = ntohs(p->param_hdr.length);
 773         nchunks = param_len - sizeof(struct sctp_paramhdr);
 774         if (nchunks == SCTP_NUM_CHUNK_TYPES)
 775                 return -EINVAL;
 776 
 777         p->chunks[nchunks] = chunk_id;
 778         p->param_hdr.length = htons(param_len + 1);
 779         return 0;
 780 }
 781 
 782 /* Add hmac identifires to the endpoint list of supported hmac ids */
 783 int sctp_auth_ep_set_hmacs(struct sctp_endpoint *ep,
 784                            struct sctp_hmacalgo *hmacs)
 785 {
 786         int has_sha1 = 0;
 787         __u16 id;
 788         int i;
 789 
 790         /* Scan the list looking for unsupported id.  Also make sure that
 791          * SHA1 is specified.
 792          */
 793         for (i = 0; i < hmacs->shmac_num_idents; i++) {
 794                 id = hmacs->shmac_idents[i];
 795 
 796                 if (id > SCTP_AUTH_HMAC_ID_MAX)
 797                         return -EOPNOTSUPP;
 798 
 799                 if (SCTP_AUTH_HMAC_ID_SHA1 == id)
 800                         has_sha1 = 1;
 801 
 802                 if (!sctp_hmac_list[id].hmac_name)
 803                         return -EOPNOTSUPP;
 804         }
 805 
 806         if (!has_sha1)
 807                 return -EINVAL;
 808 
 809         for (i = 0; i < hmacs->shmac_num_idents; i++)
 810                 ep->auth_hmacs_list->hmac_ids[i] =
 811                                 htons(hmacs->shmac_idents[i]);
 812         ep->auth_hmacs_list->param_hdr.length =
 813                         htons(sizeof(struct sctp_paramhdr) +
 814                         hmacs->shmac_num_idents * sizeof(__u16));
 815         return 0;
 816 }
 817 
 818 /* Set a new shared key on either endpoint or association.  If the
 819  * the key with a same ID already exists, replace the key (remove the
 820  * old key and add a new one).
 821  */
 822 int sctp_auth_set_key(struct sctp_endpoint *ep,
 823                       struct sctp_association *asoc,
 824                       struct sctp_authkey *auth_key)
 825 {
 826         struct sctp_shared_key *cur_key, *shkey;
 827         struct sctp_auth_bytes *key;
 828         struct list_head *sh_keys;
 829         int replace = 0;
 830 
 831         /* Try to find the given key id to see if
 832          * we are doing a replace, or adding a new key
 833          */
 834         if (asoc) {
 835                 if (!asoc->peer.auth_capable)
 836                         return -EACCES;
 837                 sh_keys = &asoc->endpoint_shared_keys;
 838         } else {
 839                 if (!ep->auth_enable)
 840                         return -EACCES;
 841                 sh_keys = &ep->endpoint_shared_keys;
 842         }
 843 
 844         key_for_each(shkey, sh_keys) {
 845                 if (shkey->key_id == auth_key->sca_keynumber) {
 846                         replace = 1;
 847                         break;
 848                 }
 849         }
 850 
 851         cur_key = sctp_auth_shkey_create(auth_key->sca_keynumber, GFP_KERNEL);
 852         if (!cur_key)
 853                 return -ENOMEM;
 854 
 855         /* Create a new key data based on the info passed in */
 856         key = sctp_auth_create_key(auth_key->sca_keylength, GFP_KERNEL);
 857         if (!key) {
 858                 kfree(cur_key);
 859                 return -ENOMEM;
 860         }
 861 
 862         memcpy(key->data, &auth_key->sca_key[0], auth_key->sca_keylength);
 863         cur_key->key = key;
 864 
 865         if (replace) {
 866                 list_del_init(&shkey->key_list);
 867                 sctp_auth_shkey_release(shkey);
 868         }
 869         list_add(&cur_key->key_list, sh_keys);
 870 
 871         return 0;
 872 }
 873 
 874 int sctp_auth_set_active_key(struct sctp_endpoint *ep,
 875                              struct sctp_association *asoc,
 876                              __u16  key_id)
 877 {
 878         struct sctp_shared_key *key;
 879         struct list_head *sh_keys;
 880         int found = 0;
 881 
 882         /* The key identifier MUST correst to an existing key */
 883         if (asoc) {
 884                 if (!asoc->peer.auth_capable)
 885                         return -EACCES;
 886                 sh_keys = &asoc->endpoint_shared_keys;
 887         } else {
 888                 if (!ep->auth_enable)
 889                         return -EACCES;
 890                 sh_keys = &ep->endpoint_shared_keys;
 891         }
 892 
 893         key_for_each(key, sh_keys) {
 894                 if (key->key_id == key_id) {
 895                         found = 1;
 896                         break;
 897                 }
 898         }
 899 
 900         if (!found || key->deactivated)
 901                 return -EINVAL;
 902 
 903         if (asoc) {
 904                 asoc->active_key_id = key_id;
 905                 sctp_auth_asoc_init_active_key(asoc, GFP_KERNEL);
 906         } else
 907                 ep->active_key_id = key_id;
 908 
 909         return 0;
 910 }
 911 
 912 int sctp_auth_del_key_id(struct sctp_endpoint *ep,
 913                          struct sctp_association *asoc,
 914                          __u16  key_id)
 915 {
 916         struct sctp_shared_key *key;
 917         struct list_head *sh_keys;
 918         int found = 0;
 919 
 920         /* The key identifier MUST NOT be the current active key
 921          * The key identifier MUST correst to an existing key
 922          */
 923         if (asoc) {
 924                 if (!asoc->peer.auth_capable)
 925                         return -EACCES;
 926                 if (asoc->active_key_id == key_id)
 927                         return -EINVAL;
 928 
 929                 sh_keys = &asoc->endpoint_shared_keys;
 930         } else {
 931                 if (!ep->auth_enable)
 932                         return -EACCES;
 933                 if (ep->active_key_id == key_id)
 934                         return -EINVAL;
 935 
 936                 sh_keys = &ep->endpoint_shared_keys;
 937         }
 938 
 939         key_for_each(key, sh_keys) {
 940                 if (key->key_id == key_id) {
 941                         found = 1;
 942                         break;
 943                 }
 944         }
 945 
 946         if (!found)
 947                 return -EINVAL;
 948 
 949         /* Delete the shared key */
 950         list_del_init(&key->key_list);
 951         sctp_auth_shkey_release(key);
 952 
 953         return 0;
 954 }
 955 
 956 int sctp_auth_deact_key_id(struct sctp_endpoint *ep,
 957                            struct sctp_association *asoc, __u16  key_id)
 958 {
 959         struct sctp_shared_key *key;
 960         struct list_head *sh_keys;
 961         int found = 0;
 962 
 963         /* The key identifier MUST NOT be the current active key
 964          * The key identifier MUST correst to an existing key
 965          */
 966         if (asoc) {
 967                 if (!asoc->peer.auth_capable)
 968                         return -EACCES;
 969                 if (asoc->active_key_id == key_id)
 970                         return -EINVAL;
 971 
 972                 sh_keys = &asoc->endpoint_shared_keys;
 973         } else {
 974                 if (!ep->auth_enable)
 975                         return -EACCES;
 976                 if (ep->active_key_id == key_id)
 977                         return -EINVAL;
 978 
 979                 sh_keys = &ep->endpoint_shared_keys;
 980         }
 981 
 982         key_for_each(key, sh_keys) {
 983                 if (key->key_id == key_id) {
 984                         found = 1;
 985                         break;
 986                 }
 987         }
 988 
 989         if (!found)
 990                 return -EINVAL;
 991 
 992         /* refcnt == 1 and !list_empty mean it's not being used anywhere
 993          * and deactivated will be set, so it's time to notify userland
 994          * that this shkey can be freed.
 995          */
 996         if (asoc && !list_empty(&key->key_list) &&
 997             refcount_read(&key->refcnt) == 1) {
 998                 struct sctp_ulpevent *ev;
 999 
1000                 ev = sctp_ulpevent_make_authkey(asoc, key->key_id,
1001                                                 SCTP_AUTH_FREE_KEY, GFP_KERNEL);
1002                 if (ev)
1003                         asoc->stream.si->enqueue_event(&asoc->ulpq, ev);
1004         }
1005 
1006         key->deactivated = 1;
1007 
1008         return 0;
1009 }
1010 
1011 int sctp_auth_init(struct sctp_endpoint *ep, gfp_t gfp)
1012 {
1013         int err = -ENOMEM;
1014 
1015         /* Allocate space for HMACS and CHUNKS authentication
1016          * variables.  There are arrays that we encode directly
1017          * into parameters to make the rest of the operations easier.
1018          */
1019         if (!ep->auth_hmacs_list) {
1020                 struct sctp_hmac_algo_param *auth_hmacs;
1021 
1022                 auth_hmacs = kzalloc(struct_size(auth_hmacs, hmac_ids,
1023                                                  SCTP_AUTH_NUM_HMACS), gfp);
1024                 if (!auth_hmacs)
1025                         goto nomem;
1026                 /* Initialize the HMACS parameter.
1027                  * SCTP-AUTH: Section 3.3
1028                  *    Every endpoint supporting SCTP chunk authentication MUST
1029                  *    support the HMAC based on the SHA-1 algorithm.
1030                  */
1031                 auth_hmacs->param_hdr.type = SCTP_PARAM_HMAC_ALGO;
1032                 auth_hmacs->param_hdr.length =
1033                                 htons(sizeof(struct sctp_paramhdr) + 2);
1034                 auth_hmacs->hmac_ids[0] = htons(SCTP_AUTH_HMAC_ID_SHA1);
1035                 ep->auth_hmacs_list = auth_hmacs;
1036         }
1037 
1038         if (!ep->auth_chunk_list) {
1039                 struct sctp_chunks_param *auth_chunks;
1040 
1041                 auth_chunks = kzalloc(sizeof(*auth_chunks) +
1042                                       SCTP_NUM_CHUNK_TYPES, gfp);
1043                 if (!auth_chunks)
1044                         goto nomem;
1045                 /* Initialize the CHUNKS parameter */
1046                 auth_chunks->param_hdr.type = SCTP_PARAM_CHUNKS;
1047                 auth_chunks->param_hdr.length =
1048                                 htons(sizeof(struct sctp_paramhdr));
1049                 ep->auth_chunk_list = auth_chunks;
1050         }
1051 
1052         /* Allocate and initialize transorms arrays for supported
1053          * HMACs.
1054          */
1055         err = sctp_auth_init_hmacs(ep, gfp);
1056         if (err)
1057                 goto nomem;
1058 
1059         return 0;
1060 
1061 nomem:
1062         /* Free all allocations */
1063         kfree(ep->auth_hmacs_list);
1064         kfree(ep->auth_chunk_list);
1065         ep->auth_hmacs_list = NULL;
1066         ep->auth_chunk_list = NULL;
1067         return err;
1068 }
1069 
1070 void sctp_auth_free(struct sctp_endpoint *ep)
1071 {
1072         kfree(ep->auth_hmacs_list);
1073         kfree(ep->auth_chunk_list);
1074         ep->auth_hmacs_list = NULL;
1075         ep->auth_chunk_list = NULL;
1076         sctp_auth_destroy_hmacs(ep->auth_hmacs);
1077         ep->auth_hmacs = NULL;
1078 }