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
  22static 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
  46void 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		kfree_sensitive(key);
  53		SCTP_DBG_OBJCNT_DEC(keys);
  54	}
  55}
  56
  57/* Create a new key structure of a given length */
  58static 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 */
  79struct 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 */
  96static 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
 104void 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
 110void 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 */
 118void 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 */
 148static 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 */
 184static 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 */
 221static 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 */
 232static 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 */
 252static 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 */
 286static 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);
 342out:
 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 */
 353int 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
 374nomem:
 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 */
 383int 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 */
 429struct 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
 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 */
 454int 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
 494out_err:
 495	/* Clean up any successful allocations */
 496	sctp_auth_destroy_hmacs(ep->auth_hmacs);
 497	ep->auth_hmacs = NULL;
 498	return -ENOMEM;
 499}
 500
 501/* Destroy the hmac tfm array */
 502void sctp_auth_destroy_hmacs(struct crypto_shash *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		crypto_free_shash(auth_hmacs[i]);
 511	}
 512	kfree(auth_hmacs);
 513}
 514
 515
 516struct sctp_hmac *sctp_auth_get_hmac(__u16 hmac_id)
 517{
 518	return &sctp_hmac_list[hmac_id];
 519}
 520
 521/* Get an hmac description information that we can use to build
 522 * the AUTH chunk
 523 */
 524struct sctp_hmac *sctp_auth_asoc_get_hmac(const struct sctp_association *asoc)
 525{
 526	struct sctp_hmac_algo_param *hmacs;
 527	__u16 n_elt;
 528	__u16 id = 0;
 529	int i;
 530
 531	/* If we have a default entry, use it */
 532	if (asoc->default_hmac_id)
 533		return &sctp_hmac_list[asoc->default_hmac_id];
 534
 535	/* Since we do not have a default entry, find the first entry
 536	 * we support and return that.  Do not cache that id.
 537	 */
 538	hmacs = asoc->peer.peer_hmacs;
 539	if (!hmacs)
 540		return NULL;
 541
 542	n_elt = (ntohs(hmacs->param_hdr.length) -
 543		 sizeof(struct sctp_paramhdr)) >> 1;
 544	for (i = 0; i < n_elt; i++) {
 545		id = ntohs(hmacs->hmac_ids[i]);
 546
 547		/* Check the id is in the supported range. And
 548		 * see if we support the id.  Supported IDs have name and
 549		 * length fields set, so that we can allocate and use
 550		 * them.  We can safely just check for name, for without the
 551		 * name, we can't allocate the TFM.
 552		 */
 553		if (id > SCTP_AUTH_HMAC_ID_MAX ||
 554		    !sctp_hmac_list[id].hmac_name) {
 555			id = 0;
 556			continue;
 557		}
 558
 559		break;
 560	}
 561
 562	if (id == 0)
 563		return NULL;
 564
 565	return &sctp_hmac_list[id];
 566}
 567
 568static int __sctp_auth_find_hmacid(__be16 *hmacs, int n_elts, __be16 hmac_id)
 569{
 570	int  found = 0;
 571	int  i;
 572
 573	for (i = 0; i < n_elts; i++) {
 574		if (hmac_id == hmacs[i]) {
 575			found = 1;
 576			break;
 577		}
 578	}
 579
 580	return found;
 581}
 582
 583/* See if the HMAC_ID is one that we claim as supported */
 584int sctp_auth_asoc_verify_hmac_id(const struct sctp_association *asoc,
 585				    __be16 hmac_id)
 586{
 587	struct sctp_hmac_algo_param *hmacs;
 588	__u16 n_elt;
 589
 590	if (!asoc)
 591		return 0;
 592
 593	hmacs = (struct sctp_hmac_algo_param *)asoc->c.auth_hmacs;
 594	n_elt = (ntohs(hmacs->param_hdr.length) -
 595		 sizeof(struct sctp_paramhdr)) >> 1;
 596
 597	return __sctp_auth_find_hmacid(hmacs->hmac_ids, n_elt, hmac_id);
 598}
 599
 600
 601/* Cache the default HMAC id.  This to follow this text from SCTP-AUTH:
 602 * Section 6.1:
 603 *   The receiver of a HMAC-ALGO parameter SHOULD use the first listed
 604 *   algorithm it supports.
 605 */
 606void sctp_auth_asoc_set_default_hmac(struct sctp_association *asoc,
 607				     struct sctp_hmac_algo_param *hmacs)
 608{
 609	struct sctp_endpoint *ep;
 610	__u16   id;
 611	int	i;
 612	int	n_params;
 613
 614	/* if the default id is already set, use it */
 615	if (asoc->default_hmac_id)
 616		return;
 617
 618	n_params = (ntohs(hmacs->param_hdr.length) -
 619		    sizeof(struct sctp_paramhdr)) >> 1;
 620	ep = asoc->ep;
 621	for (i = 0; i < n_params; i++) {
 622		id = ntohs(hmacs->hmac_ids[i]);
 623
 624		/* Check the id is in the supported range */
 625		if (id > SCTP_AUTH_HMAC_ID_MAX)
 626			continue;
 627
 628		/* If this TFM has been allocated, use this id */
 629		if (ep->auth_hmacs[id]) {
 630			asoc->default_hmac_id = id;
 631			break;
 632		}
 633	}
 634}
 635
 636
 637/* Check to see if the given chunk is supposed to be authenticated */
 638static int __sctp_auth_cid(enum sctp_cid chunk, struct sctp_chunks_param *param)
 639{
 640	unsigned short len;
 641	int found = 0;
 642	int i;
 643
 644	if (!param || param->param_hdr.length == 0)
 645		return 0;
 646
 647	len = ntohs(param->param_hdr.length) - sizeof(struct sctp_paramhdr);
 648
 649	/* SCTP-AUTH, Section 3.2
 650	 *    The chunk types for INIT, INIT-ACK, SHUTDOWN-COMPLETE and AUTH
 651	 *    chunks MUST NOT be listed in the CHUNKS parameter.  However, if
 652	 *    a CHUNKS parameter is received then the types for INIT, INIT-ACK,
 653	 *    SHUTDOWN-COMPLETE and AUTH chunks MUST be ignored.
 654	 */
 655	for (i = 0; !found && i < len; i++) {
 656		switch (param->chunks[i]) {
 657		case SCTP_CID_INIT:
 658		case SCTP_CID_INIT_ACK:
 659		case SCTP_CID_SHUTDOWN_COMPLETE:
 660		case SCTP_CID_AUTH:
 661			break;
 662
 663		default:
 664			if (param->chunks[i] == chunk)
 665				found = 1;
 666			break;
 667		}
 668	}
 669
 670	return found;
 671}
 672
 673/* Check if peer requested that this chunk is authenticated */
 674int sctp_auth_send_cid(enum sctp_cid chunk, const struct sctp_association *asoc)
 675{
 676	if (!asoc)
 677		return 0;
 678
 679	if (!asoc->peer.auth_capable)
 680		return 0;
 681
 682	return __sctp_auth_cid(chunk, asoc->peer.peer_chunks);
 683}
 684
 685/* Check if we requested that peer authenticate this chunk. */
 686int sctp_auth_recv_cid(enum sctp_cid chunk, const struct sctp_association *asoc)
 687{
 688	if (!asoc)
 689		return 0;
 690
 691	if (!asoc->peer.auth_capable)
 692		return 0;
 693
 694	return __sctp_auth_cid(chunk,
 695			      (struct sctp_chunks_param *)asoc->c.auth_chunks);
 696}
 697
 698/* SCTP-AUTH: Section 6.2:
 699 *    The sender MUST calculate the MAC as described in RFC2104 [2] using
 700 *    the hash function H as described by the MAC Identifier and the shared
 701 *    association key K based on the endpoint pair shared key described by
 702 *    the shared key identifier.  The 'data' used for the computation of
 703 *    the AUTH-chunk is given by the AUTH chunk with its HMAC field set to
 704 *    zero (as shown in Figure 6) followed by all chunks that are placed
 705 *    after the AUTH chunk in the SCTP packet.
 706 */
 707void sctp_auth_calculate_hmac(const struct sctp_association *asoc,
 708			      struct sk_buff *skb, struct sctp_auth_chunk *auth,
 709			      struct sctp_shared_key *ep_key, gfp_t gfp)
 710{
 711	struct sctp_auth_bytes *asoc_key;
 712	struct crypto_shash *tfm;
 713	__u16 key_id, hmac_id;
 714	unsigned char *end;
 715	int free_key = 0;
 716	__u8 *digest;
 717
 718	/* Extract the info we need:
 719	 * - hmac id
 720	 * - key id
 721	 */
 722	key_id = ntohs(auth->auth_hdr.shkey_id);
 723	hmac_id = ntohs(auth->auth_hdr.hmac_id);
 724
 725	if (key_id == asoc->active_key_id)
 726		asoc_key = asoc->asoc_shared_key;
 727	else {
 728		/* ep_key can't be NULL here */
 729		asoc_key = sctp_auth_asoc_create_secret(asoc, ep_key, gfp);
 730		if (!asoc_key)
 731			return;
 732
 733		free_key = 1;
 734	}
 735
 736	/* set up scatter list */
 737	end = skb_tail_pointer(skb);
 738
 739	tfm = asoc->ep->auth_hmacs[hmac_id];
 740
 741	digest = (u8 *)(&auth->auth_hdr + 1);
 742	if (crypto_shash_setkey(tfm, &asoc_key->data[0], asoc_key->len))
 743		goto free;
 744
 745	crypto_shash_tfm_digest(tfm, (u8 *)auth, end - (unsigned char *)auth,
 746				digest);
 747
 748free:
 749	if (free_key)
 750		sctp_auth_key_put(asoc_key);
 751}
 752
 753/* API Helpers */
 754
 755/* Add a chunk to the endpoint authenticated chunk list */
 756int sctp_auth_ep_add_chunkid(struct sctp_endpoint *ep, __u8 chunk_id)
 757{
 758	struct sctp_chunks_param *p = ep->auth_chunk_list;
 759	__u16 nchunks;
 760	__u16 param_len;
 761
 762	/* If this chunk is already specified, we are done */
 763	if (__sctp_auth_cid(chunk_id, p))
 764		return 0;
 765
 766	/* Check if we can add this chunk to the array */
 767	param_len = ntohs(p->param_hdr.length);
 768	nchunks = param_len - sizeof(struct sctp_paramhdr);
 769	if (nchunks == SCTP_NUM_CHUNK_TYPES)
 770		return -EINVAL;
 771
 772	p->chunks[nchunks] = chunk_id;
 773	p->param_hdr.length = htons(param_len + 1);
 774	return 0;
 775}
 776
 777/* Add hmac identifires to the endpoint list of supported hmac ids */
 778int sctp_auth_ep_set_hmacs(struct sctp_endpoint *ep,
 779			   struct sctp_hmacalgo *hmacs)
 780{
 781	int has_sha1 = 0;
 782	__u16 id;
 783	int i;
 784
 785	/* Scan the list looking for unsupported id.  Also make sure that
 786	 * SHA1 is specified.
 787	 */
 788	for (i = 0; i < hmacs->shmac_num_idents; i++) {
 789		id = hmacs->shmac_idents[i];
 790
 791		if (id > SCTP_AUTH_HMAC_ID_MAX)
 792			return -EOPNOTSUPP;
 793
 794		if (SCTP_AUTH_HMAC_ID_SHA1 == id)
 795			has_sha1 = 1;
 796
 797		if (!sctp_hmac_list[id].hmac_name)
 798			return -EOPNOTSUPP;
 799	}
 800
 801	if (!has_sha1)
 802		return -EINVAL;
 803
 804	for (i = 0; i < hmacs->shmac_num_idents; i++)
 805		ep->auth_hmacs_list->hmac_ids[i] =
 806				htons(hmacs->shmac_idents[i]);
 807	ep->auth_hmacs_list->param_hdr.length =
 808			htons(sizeof(struct sctp_paramhdr) +
 809			hmacs->shmac_num_idents * sizeof(__u16));
 810	return 0;
 811}
 812
 813/* Set a new shared key on either endpoint or association.  If the
 814 * key with a same ID already exists, replace the key (remove the
 815 * old key and add a new one).
 816 */
 817int sctp_auth_set_key(struct sctp_endpoint *ep,
 818		      struct sctp_association *asoc,
 819		      struct sctp_authkey *auth_key)
 820{
 821	struct sctp_shared_key *cur_key, *shkey;
 822	struct sctp_auth_bytes *key;
 823	struct list_head *sh_keys;
 824	int replace = 0;
 825
 826	/* Try to find the given key id to see if
 827	 * we are doing a replace, or adding a new key
 828	 */
 829	if (asoc) {
 830		if (!asoc->peer.auth_capable)
 831			return -EACCES;
 832		sh_keys = &asoc->endpoint_shared_keys;
 833	} else {
 834		if (!ep->auth_enable)
 835			return -EACCES;
 836		sh_keys = &ep->endpoint_shared_keys;
 837	}
 838
 839	key_for_each(shkey, sh_keys) {
 840		if (shkey->key_id == auth_key->sca_keynumber) {
 841			replace = 1;
 842			break;
 843		}
 844	}
 845
 846	cur_key = sctp_auth_shkey_create(auth_key->sca_keynumber, GFP_KERNEL);
 847	if (!cur_key)
 848		return -ENOMEM;
 849
 850	/* Create a new key data based on the info passed in */
 851	key = sctp_auth_create_key(auth_key->sca_keylength, GFP_KERNEL);
 852	if (!key) {
 853		kfree(cur_key);
 854		return -ENOMEM;
 855	}
 856
 857	memcpy(key->data, &auth_key->sca_key[0], auth_key->sca_keylength);
 858	cur_key->key = key;
 859
 860	if (!replace) {
 861		list_add(&cur_key->key_list, sh_keys);
 862		return 0;
 863	}
 864
 865	list_del_init(&shkey->key_list);
 866	list_add(&cur_key->key_list, sh_keys);
 867
 868	if (asoc && asoc->active_key_id == auth_key->sca_keynumber &&
 869	    sctp_auth_asoc_init_active_key(asoc, GFP_KERNEL)) {
 870		list_del_init(&cur_key->key_list);
 871		sctp_auth_shkey_release(cur_key);
 872		list_add(&shkey->key_list, sh_keys);
 873		return -ENOMEM;
 874	}
 875
 876	sctp_auth_shkey_release(shkey);
 877	return 0;
 878}
 879
 880int sctp_auth_set_active_key(struct sctp_endpoint *ep,
 881			     struct sctp_association *asoc,
 882			     __u16  key_id)
 883{
 884	struct sctp_shared_key *key;
 885	struct list_head *sh_keys;
 886	int found = 0;
 887
 888	/* The key identifier MUST correst to an existing key */
 889	if (asoc) {
 890		if (!asoc->peer.auth_capable)
 891			return -EACCES;
 892		sh_keys = &asoc->endpoint_shared_keys;
 893	} else {
 894		if (!ep->auth_enable)
 895			return -EACCES;
 896		sh_keys = &ep->endpoint_shared_keys;
 897	}
 898
 899	key_for_each(key, sh_keys) {
 900		if (key->key_id == key_id) {
 901			found = 1;
 902			break;
 903		}
 904	}
 905
 906	if (!found || key->deactivated)
 907		return -EINVAL;
 908
 909	if (asoc) {
 910		__u16  active_key_id = asoc->active_key_id;
 911
 912		asoc->active_key_id = key_id;
 913		if (sctp_auth_asoc_init_active_key(asoc, GFP_KERNEL)) {
 914			asoc->active_key_id = active_key_id;
 915			return -ENOMEM;
 916		}
 917	} else
 918		ep->active_key_id = key_id;
 919
 920	return 0;
 921}
 922
 923int sctp_auth_del_key_id(struct sctp_endpoint *ep,
 924			 struct sctp_association *asoc,
 925			 __u16  key_id)
 926{
 927	struct sctp_shared_key *key;
 928	struct list_head *sh_keys;
 929	int found = 0;
 930
 931	/* The key identifier MUST NOT be the current active key
 932	 * The key identifier MUST correst to an existing key
 933	 */
 934	if (asoc) {
 935		if (!asoc->peer.auth_capable)
 936			return -EACCES;
 937		if (asoc->active_key_id == key_id)
 938			return -EINVAL;
 939
 940		sh_keys = &asoc->endpoint_shared_keys;
 941	} else {
 942		if (!ep->auth_enable)
 943			return -EACCES;
 944		if (ep->active_key_id == key_id)
 945			return -EINVAL;
 946
 947		sh_keys = &ep->endpoint_shared_keys;
 948	}
 949
 950	key_for_each(key, sh_keys) {
 951		if (key->key_id == key_id) {
 952			found = 1;
 953			break;
 954		}
 955	}
 956
 957	if (!found)
 958		return -EINVAL;
 959
 960	/* Delete the shared key */
 961	list_del_init(&key->key_list);
 962	sctp_auth_shkey_release(key);
 963
 964	return 0;
 965}
 966
 967int sctp_auth_deact_key_id(struct sctp_endpoint *ep,
 968			   struct sctp_association *asoc, __u16  key_id)
 969{
 970	struct sctp_shared_key *key;
 971	struct list_head *sh_keys;
 972	int found = 0;
 973
 974	/* The key identifier MUST NOT be the current active key
 975	 * The key identifier MUST correst to an existing key
 976	 */
 977	if (asoc) {
 978		if (!asoc->peer.auth_capable)
 979			return -EACCES;
 980		if (asoc->active_key_id == key_id)
 981			return -EINVAL;
 982
 983		sh_keys = &asoc->endpoint_shared_keys;
 984	} else {
 985		if (!ep->auth_enable)
 986			return -EACCES;
 987		if (ep->active_key_id == key_id)
 988			return -EINVAL;
 989
 990		sh_keys = &ep->endpoint_shared_keys;
 991	}
 992
 993	key_for_each(key, sh_keys) {
 994		if (key->key_id == key_id) {
 995			found = 1;
 996			break;
 997		}
 998	}
 999
1000	if (!found)
1001		return -EINVAL;
1002
1003	/* refcnt == 1 and !list_empty mean it's not being used anywhere
1004	 * and deactivated will be set, so it's time to notify userland
1005	 * that this shkey can be freed.
1006	 */
1007	if (asoc && !list_empty(&key->key_list) &&
1008	    refcount_read(&key->refcnt) == 1) {
1009		struct sctp_ulpevent *ev;
1010
1011		ev = sctp_ulpevent_make_authkey(asoc, key->key_id,
1012						SCTP_AUTH_FREE_KEY, GFP_KERNEL);
1013		if (ev)
1014			asoc->stream.si->enqueue_event(&asoc->ulpq, ev);
1015	}
1016
1017	key->deactivated = 1;
1018
1019	return 0;
1020}
1021
1022int sctp_auth_init(struct sctp_endpoint *ep, gfp_t gfp)
1023{
1024	int err = -ENOMEM;
1025
1026	/* Allocate space for HMACS and CHUNKS authentication
1027	 * variables.  There are arrays that we encode directly
1028	 * into parameters to make the rest of the operations easier.
1029	 */
1030	if (!ep->auth_hmacs_list) {
1031		struct sctp_hmac_algo_param *auth_hmacs;
1032
1033		auth_hmacs = kzalloc(struct_size(auth_hmacs, hmac_ids,
1034						 SCTP_AUTH_NUM_HMACS), gfp);
1035		if (!auth_hmacs)
1036			goto nomem;
1037		/* Initialize the HMACS parameter.
1038		 * SCTP-AUTH: Section 3.3
1039		 *    Every endpoint supporting SCTP chunk authentication MUST
1040		 *    support the HMAC based on the SHA-1 algorithm.
1041		 */
1042		auth_hmacs->param_hdr.type = SCTP_PARAM_HMAC_ALGO;
1043		auth_hmacs->param_hdr.length =
1044				htons(sizeof(struct sctp_paramhdr) + 2);
1045		auth_hmacs->hmac_ids[0] = htons(SCTP_AUTH_HMAC_ID_SHA1);
1046		ep->auth_hmacs_list = auth_hmacs;
1047	}
1048
1049	if (!ep->auth_chunk_list) {
1050		struct sctp_chunks_param *auth_chunks;
1051
1052		auth_chunks = kzalloc(sizeof(*auth_chunks) +
1053				      SCTP_NUM_CHUNK_TYPES, gfp);
1054		if (!auth_chunks)
1055			goto nomem;
1056		/* Initialize the CHUNKS parameter */
1057		auth_chunks->param_hdr.type = SCTP_PARAM_CHUNKS;
1058		auth_chunks->param_hdr.length =
1059				htons(sizeof(struct sctp_paramhdr));
1060		ep->auth_chunk_list = auth_chunks;
1061	}
1062
1063	/* Allocate and initialize transorms arrays for supported
1064	 * HMACs.
1065	 */
1066	err = sctp_auth_init_hmacs(ep, gfp);
1067	if (err)
1068		goto nomem;
1069
1070	return 0;
1071
1072nomem:
1073	/* Free all allocations */
1074	kfree(ep->auth_hmacs_list);
1075	kfree(ep->auth_chunk_list);
1076	ep->auth_hmacs_list = NULL;
1077	ep->auth_chunk_list = NULL;
1078	return err;
1079}
1080
1081void sctp_auth_free(struct sctp_endpoint *ep)
1082{
1083	kfree(ep->auth_hmacs_list);
1084	kfree(ep->auth_chunk_list);
1085	ep->auth_hmacs_list = NULL;
1086	ep->auth_chunk_list = NULL;
1087	sctp_auth_destroy_hmacs(ep->auth_hmacs);
1088	ep->auth_hmacs = NULL;
1089}