diff options
Diffstat (limited to 'net/sctp')
| -rw-r--r-- | net/sctp/Makefile | 3 | ||||
| -rw-r--r-- | net/sctp/auth.c | 745 | ||||
| -rw-r--r-- | net/sctp/objcnt.c | 2 |
3 files changed, 749 insertions, 1 deletions
diff --git a/net/sctp/Makefile b/net/sctp/Makefile index 70c828bbe444..1da7204d9b42 100644 --- a/net/sctp/Makefile +++ b/net/sctp/Makefile @@ -9,7 +9,8 @@ sctp-y := sm_statetable.o sm_statefuns.o sm_sideeffect.o \ transport.o chunk.o sm_make_chunk.o ulpevent.o \ inqueue.o outqueue.o ulpqueue.o command.o \ tsnmap.o bind_addr.o socket.o primitive.o \ - output.o input.o debug.o ssnmap.o proc.o crc32c.o + output.o input.o debug.o ssnmap.o proc.o crc32c.o \ + auth.o sctp-$(CONFIG_SCTP_DBG_OBJCNT) += objcnt.o sctp-$(CONFIG_SYSCTL) += sysctl.o diff --git a/net/sctp/auth.c b/net/sctp/auth.c new file mode 100644 index 000000000000..2a29409a38d9 --- /dev/null +++ b/net/sctp/auth.c @@ -0,0 +1,745 @@ +/* SCTP kernel reference Implementation + * (C) Copyright 2007 Hewlett-Packard Development Company, L.P. + * + * This file is part of the SCTP kernel reference Implementation + * + * The SCTP reference 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. + * + * The SCTP reference 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, + }, + { + .hmac_id = SCTP_AUTH_HMAC_ID_SHA256, + .hmac_name="hmac(sha256)", + .hmac_len = SCTP_SHA256_SIG_SIZE, + } +}; + + +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; + + /* 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 */ +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 */ +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 */ +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 = NULL; + + /* First search associations set of endpoint pair shared keys */ + key_for_each(key, &asoc->endpoint_shared_keys) { + if (key->key_id == key_id) + break; + } + + return key; +} + +/* + * 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(__u16 *hmacs, int n_elts, __u16 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, + __u16 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) + 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.page = virt_to_page(auth); + sg.offset = (unsigned long)(auth) % PAGE_SIZE; + sg.length = 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); +} diff --git a/net/sctp/objcnt.c b/net/sctp/objcnt.c index fcfb9d806de1..2cf6ad6ff8ce 100644 --- a/net/sctp/objcnt.c +++ b/net/sctp/objcnt.c @@ -58,6 +58,7 @@ SCTP_DBG_OBJCNT(chunk); SCTP_DBG_OBJCNT(addr); SCTP_DBG_OBJCNT(ssnmap); SCTP_DBG_OBJCNT(datamsg); +SCTP_DBG_OBJCNT(keys); /* An array to make it easy to pretty print the debug information * to the proc fs. @@ -73,6 +74,7 @@ static sctp_dbg_objcnt_entry_t sctp_dbg_objcnt[] = { SCTP_DBG_OBJCNT_ENTRY(addr), SCTP_DBG_OBJCNT_ENTRY(ssnmap), SCTP_DBG_OBJCNT_ENTRY(datamsg), + SCTP_DBG_OBJCNT_ENTRY(keys), }; /* Callback from procfs to read out objcount information. |