/* SCTP kernel implementation * (C) Copyright 2007 Hewlett-Packard Development Company, L.P. * * This file is part of the SCTP kernel implementation * * This SCTP implementation is free software; * you can redistribute it and/or modify it under the terms of * the GNU General Public License as published by * the Free Software Foundation; either version 2, or (at your option) * any later version. * * This SCTP implementation is distributed in the hope that it * will be useful, but WITHOUT ANY WARRANTY; without even the implied * ************************ * warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. * See the GNU General Public License for more details. * * You should have received a copy of the GNU General Public License * along with GNU CC; see the file COPYING. If not, write to * the Free Software Foundation, 59 Temple Place - Suite 330, * Boston, MA 02111-1307, USA. * * Please send any bug reports or fixes you make to the * email address(es): * lksctp developers <lksctp-developers@lists.sourceforge.net> * * Or submit a bug report through the following website: * http://www.sf.net/projects/lksctp * * Written or modified by: * Vlad Yasevich <vladislav.yasevich@hp.com> * * Any bugs reported given to us we will try to fix... any fixes shared will * be incorporated into the next SCTP release. */ #include <linux/types.h> #include <linux/crypto.h> #include <linux/scatterlist.h> #include <net/sctp/sctp.h> #include <net/sctp/auth.h> static struct sctp_hmac sctp_hmac_list[SCTP_AUTH_NUM_HMACS] = { { /* id 0 is reserved. as all 0 */ .hmac_id = SCTP_AUTH_HMAC_ID_RESERVED_0, }, { .hmac_id = SCTP_AUTH_HMAC_ID_SHA1, .hmac_name="hmac(sha1)", .hmac_len = SCTP_SHA1_SIG_SIZE, }, { /* id 2 is reserved as well */ .hmac_id = SCTP_AUTH_HMAC_ID_RESERVED_2, }, #if defined (CONFIG_CRYPTO_SHA256) || defined (CONFIG_CRYPTO_SHA256_MODULE) { .hmac_id = SCTP_AUTH_HMAC_ID_SHA256, .hmac_name="hmac(sha256)", .hmac_len = SCTP_SHA256_SIG_SIZE, } #endif }; void sctp_auth_key_put(struct sctp_auth_bytes *key) { if (!key) return; if (atomic_dec_and_test(&key->refcnt)) { kfree(key); SCTP_DBG_OBJCNT_DEC(keys); } } /* Create a new key structure of a given length */ static struct sctp_auth_bytes *sctp_auth_create_key(__u32 key_len, gfp_t gfp) { struct sctp_auth_bytes *key; /* Verify that we are not going to overflow INT_MAX */ if ((INT_MAX - key_len) < sizeof(struct sctp_auth_bytes)) return NULL; /* Allocate the shared key */ key = kmalloc(sizeof(struct sctp_auth_bytes) + key_len, gfp); if (!key) return NULL; key->len = key_len; atomic_set(&key->refcnt, 1); SCTP_DBG_OBJCNT_INC(keys); return key; } /* Create a new shared key container with a give key id */ struct sctp_shared_key *sctp_auth_shkey_create(__u16 key_id, gfp_t gfp) { struct sctp_shared_key *new; /* Allocate the shared key container */ new = kzalloc(sizeof(struct sctp_shared_key), gfp); if (!new) return NULL; INIT_LIST_HEAD(&new->key_list); new->key_id = key_id; return new; } /* Free the shared key stucture */ static void sctp_auth_shkey_free(struct sctp_shared_key *sh_key) { BUG_ON(!list_empty(&sh_key->key_list)); sctp_auth_key_put(sh_key->key); sh_key->key = NULL; kfree(sh_key); } /* Destory the entire key list. This is done during the * associon and endpoint free process. */ void sctp_auth_destroy_keys(struct list_head *keys) { struct sctp_shared_key *ep_key; struct sctp_shared_key *tmp; if (list_empty(keys)) return; key_for_each_safe(ep_key, tmp, keys) { list_del_init(&ep_key->key_list); sctp_auth_shkey_free(ep_key); } } /* Compare two byte vectors as numbers. Return values * are: * 0 - vectors are equal * < 0 - vector 1 is smaller then vector2 * > 0 - vector 1 is greater then vector2 * * Algorithm is: * This is performed by selecting the numerically smaller key vector... * If the key vectors are equal as numbers but differ in length ... * the shorter vector is considered smaller * * Examples (with small values): * 000123456789 > 123456789 (first number is longer) * 000123456789 < 234567891 (second number is larger numerically) * 123456789 > 2345678 (first number is both larger & longer) */ static int sctp_auth_compare_vectors(struct sctp_auth_bytes *vector1, struct sctp_auth_bytes *vector2) { int diff; int i; const __u8 *longer; diff = vector1->len - vector2->len; if (diff) { longer = (diff > 0) ? vector1->data : vector2->data; /* Check to see if the longer number is * lead-zero padded. If it is not, it * is automatically larger numerically. */ for (i = 0; i < abs(diff); i++ ) { if (longer[i] != 0) return diff; } } /* lengths are the same, compare numbers */ return memcmp(vector1->data, vector2->data, vector1->len); } /* * Create a key vector as described in SCTP-AUTH, Section 6.1 * The RANDOM parameter, the CHUNKS parameter and the HMAC-ALGO * parameter sent by each endpoint are concatenated as byte vectors. * These parameters include the parameter type, parameter length, and * the parameter value, but padding is omitted; all padding MUST be * removed from this concatenation before proceeding with further * computation of keys. Parameters which were not sent are simply * omitted from the concatenation process. The resulting two vectors * are called the two key vectors. */ static struct sctp_auth_bytes *sctp_auth_make_key_vector( sctp_random_param_t *random, sctp_chunks_param_t *chunks, sctp_hmac_algo_param_t *hmacs, gfp_t gfp) { struct sctp_auth_bytes *new; __u32 len; __u32 offset = 0; len = ntohs(random->param_hdr.length) + ntohs(hmacs->param_hdr.length); if (chunks) len += ntohs(chunks->param_hdr.length); new = kmalloc(sizeof(struct sctp_auth_bytes) + len, gfp); if (!new) return NULL; new->len = len; memcpy(new->data, random, ntohs(random->param_hdr.length)); offset += ntohs(random->param_hdr.length); if (chunks) { memcpy(new->data + offset, chunks, ntohs(chunks->param_hdr.length)); offset += ntohs(chunks->param_hdr.length); } memcpy(new->data + offset, hmacs, ntohs(hmacs->param_hdr.length)); return new; } /* Make a key vector based on our local parameters */ static struct sctp_auth_bytes *sctp_auth_make_local_vector( const struct sctp_association *asoc, gfp_t gfp) { return sctp_auth_make_key_vector( (sctp_random_param_t*)asoc->c.auth_random, (sctp_chunks_param_t*)asoc->c.auth_chunks, (sctp_hmac_algo_param_t*)asoc->c.auth_hmacs, gfp); } /* Make a key vector based on peer's parameters */ static struct sctp_auth_bytes *sctp_auth_make_peer_vector( const struct sctp_association *asoc, gfp_t gfp) { return sctp_auth_make_key_vector(asoc->peer.peer_random, asoc->peer.peer_chunks, asoc->peer.peer_hmacs, gfp); } /* Set the value of the association shared key base on the parameters * given. The algorithm is: * From the endpoint pair shared keys and the key vectors the * association shared keys are computed. This is performed by selecting * the numerically smaller key vector and concatenating it to the * endpoint pair shared key, and then concatenating the numerically * larger key vector to that. The result of the concatenation is the * association shared key. */ static struct sctp_auth_bytes *sctp_auth_asoc_set_secret( struct sctp_shared_key *ep_key, struct sctp_auth_bytes *first_vector, struct sctp_auth_bytes *last_vector, gfp_t gfp) { struct sctp_auth_bytes *secret; __u32 offset = 0; __u32 auth_len; auth_len = first_vector->len + last_vector->len; if (ep_key->key) auth_len += ep_key->key->len; secret = sctp_auth_create_key(auth_len, gfp); if (!secret) return NULL; if (ep_key->key) { memcpy(secret->data, ep_key->key->data, ep_key->key->len); offset += ep_key->key->len; } memcpy(secret->data + offset, first_vector->data, first_vector->len); offset += first_vector->len; memcpy(secret->data + offset, last_vector->data, last_vector->len); return secret; } /* Create an association shared key. Follow the algorithm * described in SCTP-AUTH, Section 6.1 */ static struct sctp_auth_bytes *sctp_auth_asoc_create_secret( const struct sctp_association *asoc, struct sctp_shared_key *ep_key, gfp_t gfp) { struct sctp_auth_bytes *local_key_vector; struct sctp_auth_bytes *peer_key_vector; struct sctp_auth_bytes *first_vector, *last_vector; struct sctp_auth_bytes *secret = NULL; int cmp; /* Now we need to build the key vectors * SCTP-AUTH , Section 6.1 * The RANDOM parameter, the CHUNKS parameter and the HMAC-ALGO * parameter sent by each endpoint are concatenated as byte vectors. * These parameters include the parameter type, parameter length, and * the parameter value, but padding is omitted; all padding MUST be * removed from this concatenation before proceeding with further * computation of keys. Parameters which were not sent are simply * omitted from the concatenation process. The resulting two vectors * are called the two key vectors. */ local_key_vector = sctp_auth_make_local_vector(asoc, gfp); peer_key_vector = sctp_auth_make_peer_vector(asoc, gfp); if (!peer_key_vector || !local_key_vector) goto out; /* Figure out the order in wich the key_vectors will be * added to the endpoint shared key. * SCTP-AUTH, Section 6.1: * This is performed by selecting the numerically smaller key * vector and concatenating it to the endpoint pair shared * key, and then concatenating the numerically larger key * vector to that. If the key vectors are equal as numbers * but differ in length, then the concatenation order is the * endpoint shared key, followed by the shorter key vector, * followed by the longer key vector. Otherwise, the key * vectors are identical, and may be concatenated to the * endpoint pair key in any order. */ cmp = sctp_auth_compare_vectors(local_key_vector, peer_key_vector); if (cmp < 0) { first_vector = local_key_vector; last_vector = peer_key_vector; } else { first_vector = peer_key_vector; last_vector = local_key_vector; } secret = sctp_auth_asoc_set_secret(ep_key, first_vector, last_vector, gfp); out: kfree(local_key_vector); kfree(peer_key_vector); return secret; } /* * Populate the association overlay list with the list * from the endpoint. */ int sctp_auth_asoc_copy_shkeys(const struct sctp_endpoint *ep, struct sctp_association *asoc, gfp_t gfp) { struct sctp_shared_key *sh_key; struct sctp_shared_key *new; BUG_ON(!list_empty(&asoc->endpoint_shared_keys)); key_for_each(sh_key, &ep->endpoint_shared_keys) { new = sctp_auth_shkey_create(sh_key->key_id, gfp); if (!new) goto nomem; new->key = sh_key->key; sctp_auth_key_hold(new->key); list_add(&new->key_list, &asoc->endpoint_shared_keys); } return 0; nomem: sctp_auth_destroy_keys(&asoc->endpoint_shared_keys); return -ENOMEM; } /* Public interface to creat the association shared key. * See code above for the algorithm. */ int sctp_auth_asoc_init_active_key(struct sctp_association *asoc, gfp_t gfp) { struct sctp_auth_bytes *secret; struct sctp_shared_key *ep_key; /* If we don't support AUTH, or peer is not capable * we don't need to do anything. */ if (!sctp_auth_enable || !asoc->peer.auth_capable) return 0; /* If the key_id is non-zero and we couldn't find an * endpoint pair shared key, we can't compute the * secret. * For key_id 0, endpoint pair shared key is a NULL key. */ ep_key = sctp_auth_get_shkey(asoc, asoc->active_key_id); BUG_ON(!ep_key); secret = sctp_auth_asoc_create_secret(asoc, ep_key, gfp); if (!secret) return -ENOMEM; sctp_auth_key_put(asoc->asoc_shared_key); asoc->asoc_shared_key = secret; return 0; } /* Find the endpoint pair shared key based on the key_id */ struct sctp_shared_key *sctp_auth_get_shkey( const struct sctp_association *asoc, __u16 key_id) { struct sctp_shared_key *key; /* First search associations set of endpoint pair shared keys */ key_for_each(key, &asoc->endpoint_shared_keys) { if (key->key_id == key_id) return key; } return NULL; } /* * Initialize all the possible digest transforms that we can use. Right now * now, the supported digests are SHA1 and SHA256. We do this here once * because of the restrictiong that transforms may only be allocated in * user context. This forces us to pre-allocated all possible transforms * at the endpoint init time. */ int sctp_auth_init_hmacs(struct sctp_endpoint *ep, gfp_t gfp) { struct crypto_hash *tfm = NULL; __u16 id; /* if the transforms are already allocted, we are done */ if (!sctp_auth_enable) { ep->auth_hmacs = NULL; return 0; } if (ep->auth_hmacs) return 0; /* Allocated the array of pointers to transorms */ ep->auth_hmacs = kzalloc( sizeof(struct crypto_hash *) * SCTP_AUTH_NUM_HMACS, gfp); if (!ep->auth_hmacs) return -ENOMEM; for (id = 0; id < SCTP_AUTH_NUM_HMACS; id++) { /* See is we support the id. Supported IDs have name and * length fields set, so that we can allocated and use * them. We can safely just check for name, for without the * name, we can't allocate the TFM. */ if (!sctp_hmac_list[id].hmac_name) continue; /* If this TFM has been allocated, we are all set */ if (ep->auth_hmacs[id]) continue; /* Allocate the ID */ tfm = crypto_alloc_hash(sctp_hmac_list[id].hmac_name, 0, CRYPTO_ALG_ASYNC); if (IS_ERR(tfm)) goto out_err; ep->auth_hmacs[id] = tfm; } return 0; out_err: /* Clean up any successfull allocations */ sctp_auth_destroy_hmacs(ep->auth_hmacs); return -ENOMEM; } /* Destroy the hmac tfm array */ void sctp_auth_destroy_hmacs(struct crypto_hash *auth_hmacs[]) { int i; if (!auth_hmacs) return; for (i = 0; i < SCTP_AUTH_NUM_HMACS; i++) { if (auth_hmacs[i]) crypto_free_hash(auth_hmacs[i]); } kfree(auth_hmacs); } struct sctp_hmac *sctp_auth_get_hmac(__u16 hmac_id) { return &sctp_hmac_list[hmac_id]; } /* Get an hmac description information that we can use to build * the AUTH chunk */ struct sctp_hmac *sctp_auth_asoc_get_hmac(const struct sctp_association *asoc) { struct sctp_hmac_algo_param *hmacs; __u16 n_elt; __u16 id = 0; int i; /* If we have a default entry, use it */ if (asoc->default_hmac_id) return &sctp_hmac_list[asoc->default_hmac_id]; /* Since we do not have a default entry, find the first entry * we support and return that. Do not cache that id. */ hmacs = asoc->peer.peer_hmacs; if (!hmacs) return NULL; n_elt = (ntohs(hmacs->param_hdr.length) - sizeof(sctp_paramhdr_t)) >> 1; for (i = 0; i < n_elt; i++) { id = ntohs(hmacs->hmac_ids[i]); /* Check the id is in the supported range */ if (id > SCTP_AUTH_HMAC_ID_MAX) continue; /* See is we support the id. Supported IDs have name and * length fields set, so that we can allocated and use * them. We can safely just check for name, for without the * name, we can't allocate the TFM. */ if (!sctp_hmac_list[id].hmac_name) continue; break; } if (id == 0) return NULL; return &sctp_hmac_list[id]; } static int __sctp_auth_find_hmacid(__be16 *hmacs, int n_elts, __be16 hmac_id) { int found = 0; int i; for (i = 0; i < n_elts; i++) { if (hmac_id == hmacs[i]) { found = 1; break; } } return found; } /* See if the HMAC_ID is one that we claim as supported */ int sctp_auth_asoc_verify_hmac_id(const struct sctp_association *asoc, __be16 hmac_id) { struct sctp_hmac_algo_param *hmacs; __u16 n_elt; if (!asoc) return 0; hmacs = (struct sctp_hmac_algo_param *)asoc->c.auth_hmacs; n_elt = (ntohs(hmacs->param_hdr.length) - sizeof(sctp_paramhdr_t)) >> 1; return __sctp_auth_find_hmacid(hmacs->hmac_ids, n_elt, hmac_id); } /* Cache the default HMAC id. This to follow this text from SCTP-AUTH: * Section 6.1: * The receiver of a HMAC-ALGO parameter SHOULD use the first listed * algorithm it supports. */ void sctp_auth_asoc_set_default_hmac(struct sctp_association *asoc, struct sctp_hmac_algo_param *hmacs) { struct sctp_endpoint *ep; __u16 id; int i; int n_params; /* if the default id is already set, use it */ if (asoc->default_hmac_id) return; n_params = (ntohs(hmacs->param_hdr.length) - sizeof(sctp_paramhdr_t)) >> 1; ep = asoc->ep; for (i = 0; i < n_params; i++) { id = ntohs(hmacs->hmac_ids[i]); /* Check the id is in the supported range */ if (id > SCTP_AUTH_HMAC_ID_MAX) continue; /* If this TFM has been allocated, use this id */ if (ep->auth_hmacs[id]) { asoc->default_hmac_id = id; break; } } } /* Check to see if the given chunk is supposed to be authenticated */ static int __sctp_auth_cid(sctp_cid_t chunk, struct sctp_chunks_param *param) { unsigned short len; int found = 0; int i; if (!param || param->param_hdr.length == 0) return 0; len = ntohs(param->param_hdr.length) - sizeof(sctp_paramhdr_t); /* SCTP-AUTH, Section 3.2 * The chunk types for INIT, INIT-ACK, SHUTDOWN-COMPLETE and AUTH * chunks MUST NOT be listed in the CHUNKS parameter. However, if * a CHUNKS parameter is received then the types for INIT, INIT-ACK, * SHUTDOWN-COMPLETE and AUTH chunks MUST be ignored. */ for (i = 0; !found && i < len; i++) { switch (param->chunks[i]) { case SCTP_CID_INIT: case SCTP_CID_INIT_ACK: case SCTP_CID_SHUTDOWN_COMPLETE: case SCTP_CID_AUTH: break; default: if (param->chunks[i] == chunk) found = 1; break; } } return found; } /* Check if peer requested that this chunk is authenticated */ int sctp_auth_send_cid(sctp_cid_t chunk, const struct sctp_association *asoc) { if (!sctp_auth_enable || !asoc || !asoc->peer.auth_capable) return 0; return __sctp_auth_cid(chunk, asoc->peer.peer_chunks); } /* Check if we requested that peer authenticate this chunk. */ int sctp_auth_recv_cid(sctp_cid_t chunk, const struct sctp_association *asoc) { if (!sctp_auth_enable || !asoc) return 0; return __sctp_auth_cid(chunk, (struct sctp_chunks_param *)asoc->c.auth_chunks); } /* SCTP-AUTH: Section 6.2: * The sender MUST calculate the MAC as described in RFC2104 [2] using * the hash function H as described by the MAC Identifier and the shared * association key K based on the endpoint pair shared key described by * the shared key identifier. The 'data' used for the computation of * the AUTH-chunk is given by the AUTH chunk with its HMAC field set to * zero (as shown in Figure 6) followed by all chunks that are placed * after the AUTH chunk in the SCTP packet. */ void sctp_auth_calculate_hmac(const struct sctp_association *asoc, struct sk_buff *skb, struct sctp_auth_chunk *auth, gfp_t gfp) { struct scatterlist sg; struct hash_desc desc; struct sctp_auth_bytes *asoc_key; __u16 key_id, hmac_id; __u8 *digest; unsigned char *end; int free_key = 0; /* Extract the info we need: * - hmac id * - key id */ key_id = ntohs(auth->auth_hdr.shkey_id); hmac_id = ntohs(auth->auth_hdr.hmac_id); if (key_id == asoc->active_key_id) asoc_key = asoc->asoc_shared_key; else { struct sctp_shared_key *ep_key; ep_key = sctp_auth_get_shkey(asoc, key_id); if (!ep_key) return; asoc_key = sctp_auth_asoc_create_secret(asoc, ep_key, gfp); if (!asoc_key) return; free_key = 1; } /* set up scatter list */ end = skb_tail_pointer(skb); sg_init_one(&sg, auth, end - (unsigned char *)auth); desc.tfm = asoc->ep->auth_hmacs[hmac_id]; desc.flags = 0; digest = auth->auth_hdr.hmac; if (crypto_hash_setkey(desc.tfm, &asoc_key->data[0], asoc_key->len)) goto free; crypto_hash_digest(&desc, &sg, sg.length, digest); free: if (free_key) sctp_auth_key_put(asoc_key); } /* API Helpers */ /* Add a chunk to the endpoint authenticated chunk list */ int sctp_auth_ep_add_chunkid(struct sctp_endpoint *ep, __u8 chunk_id) { struct sctp_chunks_param *p = ep->auth_chunk_list; __u16 nchunks; __u16 param_len; /* If this chunk is already specified, we are done */ if (__sctp_auth_cid(chunk_id, p)) return 0; /* Check if we can add this chunk to the array */ param_len = ntohs(p->param_hdr.length); nchunks = param_len - sizeof(sctp_paramhdr_t); if (nchunks == SCTP_NUM_CHUNK_TYPES) return -EINVAL; p->chunks[nchunks] = chunk_id; p->param_hdr.length = htons(param_len + 1); return 0; } /* Add hmac identifires to the endpoint list of supported hmac ids */ int sctp_auth_ep_set_hmacs(struct sctp_endpoint *ep, struct sctp_hmacalgo *hmacs) { int has_sha1 = 0; __u16 id; int i; /* Scan the list looking for unsupported id. Also make sure that * SHA1 is specified. */ for (i = 0; i < hmacs->shmac_num_idents; i++) { id = hmacs->shmac_idents[i]; if (id > SCTP_AUTH_HMAC_ID_MAX) return -EOPNOTSUPP; if (SCTP_AUTH_HMAC_ID_SHA1 == id) has_sha1 = 1; if (!sctp_hmac_list[id].hmac_name) return -EOPNOTSUPP; } if (!has_sha1) return -EINVAL; memcpy(ep->auth_hmacs_list->hmac_ids, &hmacs->shmac_idents[0], hmacs->shmac_num_idents * sizeof(__u16)); ep->auth_hmacs_list->param_hdr.length = htons(sizeof(sctp_paramhdr_t) + hmacs->shmac_num_idents * sizeof(__u16)); return 0; } /* Set a new shared key on either endpoint or association. If the * the key with a same ID already exists, replace the key (remove the * old key and add a new one). */ int sctp_auth_set_key(struct sctp_endpoint *ep, struct sctp_association *asoc, struct sctp_authkey *auth_key) { struct sctp_shared_key *cur_key = NULL; struct sctp_auth_bytes *key; struct list_head *sh_keys; int replace = 0; /* Try to find the given key id to see if * we are doing a replace, or adding a new key */ if (asoc) sh_keys = &asoc->endpoint_shared_keys; else sh_keys = &ep->endpoint_shared_keys; key_for_each(cur_key, sh_keys) { if (cur_key->key_id == auth_key->sca_keynumber) { replace = 1; break; } } /* If we are not replacing a key id, we need to allocate * a shared key. */ if (!replace) { cur_key = sctp_auth_shkey_create(auth_key->sca_keynumber, GFP_KERNEL); if (!cur_key) return -ENOMEM; } /* Create a new key data based on the info passed in */ key = sctp_auth_create_key(auth_key->sca_keylength, GFP_KERNEL); if (!key) goto nomem; memcpy(key->data, &auth_key->sca_key[0], auth_key->sca_keylength); /* If we are replacing, remove the old keys data from the * key id. If we are adding new key id, add it to the * list. */ if (replace) sctp_auth_key_put(cur_key->key); else list_add(&cur_key->key_list, sh_keys); cur_key->key = key; sctp_auth_key_hold(key); return 0; nomem: if (!replace) sctp_auth_shkey_free(cur_key); return -ENOMEM; } int sctp_auth_set_active_key(struct sctp_endpoint *ep, struct sctp_association *asoc, __u16 key_id) { struct sctp_shared_key *key; struct list_head *sh_keys; int found = 0; /* The key identifier MUST correst to an existing key */ if (asoc) sh_keys = &asoc->endpoint_shared_keys; else sh_keys = &ep->endpoint_shared_keys; key_for_each(key, sh_keys) { if (key->key_id == key_id) { found = 1; break; } } if (!found) return -EINVAL; if (asoc) { asoc->active_key_id = key_id; sctp_auth_asoc_init_active_key(asoc, GFP_KERNEL); } else ep->active_key_id = key_id; return 0; } int sctp_auth_del_key_id(struct sctp_endpoint *ep, struct sctp_association *asoc, __u16 key_id) { struct sctp_shared_key *key; struct list_head *sh_keys; int found = 0; /* The key identifier MUST NOT be the current active key * The key identifier MUST correst to an existing key */ if (asoc) { if (asoc->active_key_id == key_id) return -EINVAL; sh_keys = &asoc->endpoint_shared_keys; } else { if (ep->active_key_id == key_id) return -EINVAL; sh_keys = &ep->endpoint_shared_keys; } key_for_each(key, sh_keys) { if (key->key_id == key_id) { found = 1; break; } } if (!found) return -EINVAL; /* Delete the shared key */ list_del_init(&key->key_list); sctp_auth_shkey_free(key); return 0; }