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1075 lines
27 KiB
1075 lines
27 KiB
// SPDX-License-Identifier: GPL-2.0-or-later |
|
/* SCTP kernel implementation |
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* (C) Copyright 2007 Hewlett-Packard Development Company, L.P. |
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* |
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* This file is part of the SCTP kernel implementation |
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* |
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* Please send any bug reports or fixes you make to the |
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* email address(es): |
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* lksctp developers <[email protected]> |
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* |
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* Written or modified by: |
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* Vlad Yasevich <[email protected]> |
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*/ |
|
|
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#include <crypto/hash.h> |
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#include <linux/slab.h> |
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#include <linux/types.h> |
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#include <linux/scatterlist.h> |
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#include <net/sctp/sctp.h> |
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#include <net/sctp/auth.h> |
|
|
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static struct sctp_hmac sctp_hmac_list[SCTP_AUTH_NUM_HMACS] = { |
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{ |
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/* id 0 is reserved. as all 0 */ |
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.hmac_id = SCTP_AUTH_HMAC_ID_RESERVED_0, |
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}, |
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{ |
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.hmac_id = SCTP_AUTH_HMAC_ID_SHA1, |
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.hmac_name = "hmac(sha1)", |
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.hmac_len = SCTP_SHA1_SIG_SIZE, |
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}, |
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{ |
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/* id 2 is reserved as well */ |
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.hmac_id = SCTP_AUTH_HMAC_ID_RESERVED_2, |
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}, |
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#if IS_ENABLED(CONFIG_CRYPTO_SHA256) |
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{ |
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.hmac_id = SCTP_AUTH_HMAC_ID_SHA256, |
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.hmac_name = "hmac(sha256)", |
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.hmac_len = SCTP_SHA256_SIG_SIZE, |
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} |
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#endif |
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}; |
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|
|
|
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void sctp_auth_key_put(struct sctp_auth_bytes *key) |
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{ |
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if (!key) |
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return; |
|
|
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if (refcount_dec_and_test(&key->refcnt)) { |
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kfree_sensitive(key); |
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SCTP_DBG_OBJCNT_DEC(keys); |
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} |
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} |
|
|
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/* Create a new key structure of a given length */ |
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static struct sctp_auth_bytes *sctp_auth_create_key(__u32 key_len, gfp_t gfp) |
|
{ |
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struct sctp_auth_bytes *key; |
|
|
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/* Verify that we are not going to overflow INT_MAX */ |
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if (key_len > (INT_MAX - sizeof(struct sctp_auth_bytes))) |
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return NULL; |
|
|
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/* Allocate the shared key */ |
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key = kmalloc(sizeof(struct sctp_auth_bytes) + key_len, gfp); |
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if (!key) |
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return NULL; |
|
|
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key->len = key_len; |
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refcount_set(&key->refcnt, 1); |
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SCTP_DBG_OBJCNT_INC(keys); |
|
|
|
return key; |
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} |
|
|
|
/* 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) |
|
{ |
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struct sctp_shared_key *new; |
|
|
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/* Allocate the shared key container */ |
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new = kzalloc(sizeof(struct sctp_shared_key), gfp); |
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if (!new) |
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return NULL; |
|
|
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INIT_LIST_HEAD(&new->key_list); |
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refcount_set(&new->refcnt, 1); |
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new->key_id = key_id; |
|
|
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return new; |
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} |
|
|
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/* Free the shared key structure */ |
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static void sctp_auth_shkey_destroy(struct sctp_shared_key *sh_key) |
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{ |
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BUG_ON(!list_empty(&sh_key->key_list)); |
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sctp_auth_key_put(sh_key->key); |
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sh_key->key = NULL; |
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kfree(sh_key); |
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} |
|
|
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void sctp_auth_shkey_release(struct sctp_shared_key *sh_key) |
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{ |
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if (refcount_dec_and_test(&sh_key->refcnt)) |
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sctp_auth_shkey_destroy(sh_key); |
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} |
|
|
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void sctp_auth_shkey_hold(struct sctp_shared_key *sh_key) |
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{ |
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refcount_inc(&sh_key->refcnt); |
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} |
|
|
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/* Destroy the entire key list. This is done during the |
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* associon and endpoint free process. |
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*/ |
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void sctp_auth_destroy_keys(struct list_head *keys) |
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{ |
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struct sctp_shared_key *ep_key; |
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struct sctp_shared_key *tmp; |
|
|
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if (list_empty(keys)) |
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return; |
|
|
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key_for_each_safe(ep_key, tmp, keys) { |
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list_del_init(&ep_key->key_list); |
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sctp_auth_shkey_release(ep_key); |
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} |
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} |
|
|
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/* Compare two byte vectors as numbers. Return values |
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* are: |
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* 0 - vectors are equal |
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* < 0 - vector 1 is smaller than vector2 |
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* > 0 - vector 1 is greater than vector2 |
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* |
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* Algorithm is: |
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* This is performed by selecting the numerically smaller key vector... |
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* If the key vectors are equal as numbers but differ in length ... |
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* the shorter vector is considered smaller |
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* |
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* Examples (with small values): |
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* 000123456789 > 123456789 (first number is longer) |
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* 000123456789 < 234567891 (second number is larger numerically) |
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* 123456789 > 2345678 (first number is both larger & longer) |
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*/ |
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static int sctp_auth_compare_vectors(struct sctp_auth_bytes *vector1, |
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struct sctp_auth_bytes *vector2) |
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{ |
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int diff; |
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int i; |
|
const __u8 *longer; |
|
|
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diff = vector1->len - vector2->len; |
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if (diff) { |
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longer = (diff > 0) ? vector1->data : vector2->data; |
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|
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/* Check to see if the longer number is |
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* lead-zero padded. If it is not, it |
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* is automatically larger numerically. |
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*/ |
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for (i = 0; i < abs(diff); i++) { |
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if (longer[i] != 0) |
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return diff; |
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} |
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} |
|
|
|
/* lengths are the same, compare numbers */ |
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return memcmp(vector1->data, vector2->data, vector1->len); |
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} |
|
|
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/* |
|
* 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( |
|
struct sctp_random_param *random, |
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struct sctp_chunks_param *chunks, |
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struct sctp_hmac_algo_param *hmacs, |
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gfp_t gfp) |
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{ |
|
struct sctp_auth_bytes *new; |
|
__u32 len; |
|
__u32 offset = 0; |
|
__u16 random_len, hmacs_len, chunks_len = 0; |
|
|
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random_len = ntohs(random->param_hdr.length); |
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hmacs_len = ntohs(hmacs->param_hdr.length); |
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if (chunks) |
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chunks_len = ntohs(chunks->param_hdr.length); |
|
|
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len = random_len + hmacs_len + chunks_len; |
|
|
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new = sctp_auth_create_key(len, gfp); |
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if (!new) |
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return NULL; |
|
|
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memcpy(new->data, random, random_len); |
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offset += random_len; |
|
|
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if (chunks) { |
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memcpy(new->data + offset, chunks, chunks_len); |
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offset += chunks_len; |
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} |
|
|
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memcpy(new->data + offset, hmacs, hmacs_len); |
|
|
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return new; |
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} |
|
|
|
|
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/* Make a key vector based on our local parameters */ |
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static struct sctp_auth_bytes *sctp_auth_make_local_vector( |
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const struct sctp_association *asoc, |
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gfp_t gfp) |
|
{ |
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return sctp_auth_make_key_vector( |
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(struct sctp_random_param *)asoc->c.auth_random, |
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(struct sctp_chunks_param *)asoc->c.auth_chunks, |
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(struct sctp_hmac_algo_param *)asoc->c.auth_hmacs, gfp); |
|
} |
|
|
|
/* Make a key vector based on peer's parameters */ |
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static struct sctp_auth_bytes *sctp_auth_make_peer_vector( |
|
const struct sctp_association *asoc, |
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gfp_t gfp) |
|
{ |
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return sctp_auth_make_key_vector(asoc->peer.peer_random, |
|
asoc->peer.peer_chunks, |
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asoc->peer.peer_hmacs, |
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gfp); |
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} |
|
|
|
|
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/* 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 |
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* association shared keys are computed. This is performed by selecting |
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* the numerically smaller key vector and concatenating it to the |
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* endpoint pair shared key, and then concatenating the numerically |
|
* larger key vector to that. The result of the concatenation is the |
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* association shared key. |
|
*/ |
|
static struct sctp_auth_bytes *sctp_auth_asoc_set_secret( |
|
struct sctp_shared_key *ep_key, |
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struct sctp_auth_bytes *first_vector, |
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struct sctp_auth_bytes *last_vector, |
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gfp_t gfp) |
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{ |
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struct sctp_auth_bytes *secret; |
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__u32 offset = 0; |
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__u32 auth_len; |
|
|
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auth_len = first_vector->len + last_vector->len; |
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if (ep_key->key) |
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auth_len += ep_key->key->len; |
|
|
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secret = sctp_auth_create_key(auth_len, gfp); |
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if (!secret) |
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return NULL; |
|
|
|
if (ep_key->key) { |
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memcpy(secret->data, ep_key->key->data, ep_key->key->len); |
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offset += ep_key->key->len; |
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} |
|
|
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memcpy(secret->data + offset, first_vector->data, first_vector->len); |
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offset += first_vector->len; |
|
|
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memcpy(secret->data + offset, last_vector->data, last_vector->len); |
|
|
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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, |
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struct sctp_shared_key *ep_key, |
|
gfp_t gfp) |
|
{ |
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struct sctp_auth_bytes *local_key_vector; |
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struct sctp_auth_bytes *peer_key_vector; |
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struct sctp_auth_bytes *first_vector, |
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*last_vector; |
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struct sctp_auth_bytes *secret = NULL; |
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int cmp; |
|
|
|
|
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/* 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. |
|
*/ |
|
|
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local_key_vector = sctp_auth_make_local_vector(asoc, gfp); |
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peer_key_vector = sctp_auth_make_peer_vector(asoc, gfp); |
|
|
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if (!peer_key_vector || !local_key_vector) |
|
goto out; |
|
|
|
/* Figure out the order in which 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, |
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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, |
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gfp); |
|
out: |
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sctp_auth_key_put(local_key_vector); |
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sctp_auth_key_put(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; |
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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 create 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; |
|
struct sctp_chunk *chunk; |
|
|
|
/* If we don't support AUTH, or peer is not capable |
|
* we don't need to do anything. |
|
*/ |
|
if (!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; |
|
asoc->shkey = ep_key; |
|
|
|
/* Update send queue in case any chunk already in there now |
|
* needs authenticating |
|
*/ |
|
list_for_each_entry(chunk, &asoc->outqueue.out_chunk_list, list) { |
|
if (sctp_auth_send_cid(chunk->chunk_hdr->type, asoc)) { |
|
chunk->auth = 1; |
|
if (!chunk->shkey) { |
|
chunk->shkey = asoc->shkey; |
|
sctp_auth_shkey_hold(chunk->shkey); |
|
} |
|
} |
|
} |
|
|
|
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) { |
|
if (!key->deactivated) |
|
return key; |
|
break; |
|
} |
|
} |
|
|
|
return NULL; |
|
} |
|
|
|
/* |
|
* Initialize all the possible digest transforms that we can use. Right |
|
* 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_shash *tfm = NULL; |
|
__u16 id; |
|
|
|
/* If the transforms are already allocated, we are done */ |
|
if (ep->auth_hmacs) |
|
return 0; |
|
|
|
/* Allocated the array of pointers to transorms */ |
|
ep->auth_hmacs = kcalloc(SCTP_AUTH_NUM_HMACS, |
|
sizeof(struct crypto_shash *), |
|
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_shash(sctp_hmac_list[id].hmac_name, 0, 0); |
|
if (IS_ERR(tfm)) |
|
goto out_err; |
|
|
|
ep->auth_hmacs[id] = tfm; |
|
} |
|
|
|
return 0; |
|
|
|
out_err: |
|
/* Clean up any successful allocations */ |
|
sctp_auth_destroy_hmacs(ep->auth_hmacs); |
|
ep->auth_hmacs = NULL; |
|
return -ENOMEM; |
|
} |
|
|
|
/* Destroy the hmac tfm array */ |
|
void sctp_auth_destroy_hmacs(struct crypto_shash *auth_hmacs[]) |
|
{ |
|
int i; |
|
|
|
if (!auth_hmacs) |
|
return; |
|
|
|
for (i = 0; i < SCTP_AUTH_NUM_HMACS; i++) { |
|
crypto_free_shash(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(struct sctp_paramhdr)) >> 1; |
|
for (i = 0; i < n_elt; i++) { |
|
id = ntohs(hmacs->hmac_ids[i]); |
|
|
|
/* Check the id is in the supported range. And |
|
* see if we support the id. Supported IDs have name and |
|
* length fields set, so that we can allocate and use |
|
* them. We can safely just check for name, for without the |
|
* name, we can't allocate the TFM. |
|
*/ |
|
if (id > SCTP_AUTH_HMAC_ID_MAX || |
|
!sctp_hmac_list[id].hmac_name) { |
|
id = 0; |
|
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(struct sctp_paramhdr)) >> 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(struct sctp_paramhdr)) >> 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(enum sctp_cid 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(struct sctp_paramhdr); |
|
|
|
/* 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(enum sctp_cid chunk, const struct sctp_association *asoc) |
|
{ |
|
if (!asoc) |
|
return 0; |
|
|
|
if (!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(enum sctp_cid chunk, const struct sctp_association *asoc) |
|
{ |
|
if (!asoc) |
|
return 0; |
|
|
|
if (!asoc->peer.auth_capable) |
|
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, |
|
struct sctp_shared_key *ep_key, gfp_t gfp) |
|
{ |
|
struct sctp_auth_bytes *asoc_key; |
|
struct crypto_shash *tfm; |
|
__u16 key_id, hmac_id; |
|
unsigned char *end; |
|
int free_key = 0; |
|
__u8 *digest; |
|
|
|
/* 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 { |
|
/* ep_key can't be NULL here */ |
|
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); |
|
|
|
tfm = asoc->ep->auth_hmacs[hmac_id]; |
|
|
|
digest = auth->auth_hdr.hmac; |
|
if (crypto_shash_setkey(tfm, &asoc_key->data[0], asoc_key->len)) |
|
goto free; |
|
|
|
crypto_shash_tfm_digest(tfm, (u8 *)auth, end - (unsigned char *)auth, |
|
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(struct sctp_paramhdr); |
|
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; |
|
|
|
for (i = 0; i < hmacs->shmac_num_idents; i++) |
|
ep->auth_hmacs_list->hmac_ids[i] = |
|
htons(hmacs->shmac_idents[i]); |
|
ep->auth_hmacs_list->param_hdr.length = |
|
htons(sizeof(struct sctp_paramhdr) + |
|
hmacs->shmac_num_idents * sizeof(__u16)); |
|
return 0; |
|
} |
|
|
|
/* Set a new shared key on either endpoint or association. If 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, *shkey; |
|
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) { |
|
if (!asoc->peer.auth_capable) |
|
return -EACCES; |
|
sh_keys = &asoc->endpoint_shared_keys; |
|
} else { |
|
if (!ep->auth_enable) |
|
return -EACCES; |
|
sh_keys = &ep->endpoint_shared_keys; |
|
} |
|
|
|
key_for_each(shkey, sh_keys) { |
|
if (shkey->key_id == auth_key->sca_keynumber) { |
|
replace = 1; |
|
break; |
|
} |
|
} |
|
|
|
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) { |
|
kfree(cur_key); |
|
return -ENOMEM; |
|
} |
|
|
|
memcpy(key->data, &auth_key->sca_key[0], auth_key->sca_keylength); |
|
cur_key->key = key; |
|
|
|
if (replace) { |
|
list_del_init(&shkey->key_list); |
|
sctp_auth_shkey_release(shkey); |
|
if (asoc && asoc->active_key_id == auth_key->sca_keynumber) |
|
sctp_auth_asoc_init_active_key(asoc, GFP_KERNEL); |
|
} |
|
list_add(&cur_key->key_list, sh_keys); |
|
|
|
return 0; |
|
} |
|
|
|
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) { |
|
if (!asoc->peer.auth_capable) |
|
return -EACCES; |
|
sh_keys = &asoc->endpoint_shared_keys; |
|
} else { |
|
if (!ep->auth_enable) |
|
return -EACCES; |
|
sh_keys = &ep->endpoint_shared_keys; |
|
} |
|
|
|
key_for_each(key, sh_keys) { |
|
if (key->key_id == key_id) { |
|
found = 1; |
|
break; |
|
} |
|
} |
|
|
|
if (!found || key->deactivated) |
|
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->peer.auth_capable) |
|
return -EACCES; |
|
if (asoc->active_key_id == key_id) |
|
return -EINVAL; |
|
|
|
sh_keys = &asoc->endpoint_shared_keys; |
|
} else { |
|
if (!ep->auth_enable) |
|
return -EACCES; |
|
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_release(key); |
|
|
|
return 0; |
|
} |
|
|
|
int sctp_auth_deact_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->peer.auth_capable) |
|
return -EACCES; |
|
if (asoc->active_key_id == key_id) |
|
return -EINVAL; |
|
|
|
sh_keys = &asoc->endpoint_shared_keys; |
|
} else { |
|
if (!ep->auth_enable) |
|
return -EACCES; |
|
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; |
|
|
|
/* refcnt == 1 and !list_empty mean it's not being used anywhere |
|
* and deactivated will be set, so it's time to notify userland |
|
* that this shkey can be freed. |
|
*/ |
|
if (asoc && !list_empty(&key->key_list) && |
|
refcount_read(&key->refcnt) == 1) { |
|
struct sctp_ulpevent *ev; |
|
|
|
ev = sctp_ulpevent_make_authkey(asoc, key->key_id, |
|
SCTP_AUTH_FREE_KEY, GFP_KERNEL); |
|
if (ev) |
|
asoc->stream.si->enqueue_event(&asoc->ulpq, ev); |
|
} |
|
|
|
key->deactivated = 1; |
|
|
|
return 0; |
|
} |
|
|
|
int sctp_auth_init(struct sctp_endpoint *ep, gfp_t gfp) |
|
{ |
|
int err = -ENOMEM; |
|
|
|
/* Allocate space for HMACS and CHUNKS authentication |
|
* variables. There are arrays that we encode directly |
|
* into parameters to make the rest of the operations easier. |
|
*/ |
|
if (!ep->auth_hmacs_list) { |
|
struct sctp_hmac_algo_param *auth_hmacs; |
|
|
|
auth_hmacs = kzalloc(struct_size(auth_hmacs, hmac_ids, |
|
SCTP_AUTH_NUM_HMACS), gfp); |
|
if (!auth_hmacs) |
|
goto nomem; |
|
/* Initialize the HMACS parameter. |
|
* SCTP-AUTH: Section 3.3 |
|
* Every endpoint supporting SCTP chunk authentication MUST |
|
* support the HMAC based on the SHA-1 algorithm. |
|
*/ |
|
auth_hmacs->param_hdr.type = SCTP_PARAM_HMAC_ALGO; |
|
auth_hmacs->param_hdr.length = |
|
htons(sizeof(struct sctp_paramhdr) + 2); |
|
auth_hmacs->hmac_ids[0] = htons(SCTP_AUTH_HMAC_ID_SHA1); |
|
ep->auth_hmacs_list = auth_hmacs; |
|
} |
|
|
|
if (!ep->auth_chunk_list) { |
|
struct sctp_chunks_param *auth_chunks; |
|
|
|
auth_chunks = kzalloc(sizeof(*auth_chunks) + |
|
SCTP_NUM_CHUNK_TYPES, gfp); |
|
if (!auth_chunks) |
|
goto nomem; |
|
/* Initialize the CHUNKS parameter */ |
|
auth_chunks->param_hdr.type = SCTP_PARAM_CHUNKS; |
|
auth_chunks->param_hdr.length = |
|
htons(sizeof(struct sctp_paramhdr)); |
|
ep->auth_chunk_list = auth_chunks; |
|
} |
|
|
|
/* Allocate and initialize transorms arrays for supported |
|
* HMACs. |
|
*/ |
|
err = sctp_auth_init_hmacs(ep, gfp); |
|
if (err) |
|
goto nomem; |
|
|
|
return 0; |
|
|
|
nomem: |
|
/* Free all allocations */ |
|
kfree(ep->auth_hmacs_list); |
|
kfree(ep->auth_chunk_list); |
|
ep->auth_hmacs_list = NULL; |
|
ep->auth_chunk_list = NULL; |
|
return err; |
|
} |
|
|
|
void sctp_auth_free(struct sctp_endpoint *ep) |
|
{ |
|
kfree(ep->auth_hmacs_list); |
|
kfree(ep->auth_chunk_list); |
|
ep->auth_hmacs_list = NULL; |
|
ep->auth_chunk_list = NULL; |
|
sctp_auth_destroy_hmacs(ep->auth_hmacs); |
|
ep->auth_hmacs = NULL; |
|
}
|
|
|