sctp_auth.c

Go to the documentation of this file.

/*-
 * SPDX-License-Identifier: BSD-3-Clause
 *
 * Copyright (c) 2001-2008, by Cisco Systems, Inc. All rights reserved.
 * Copyright (c) 2008-2012, by Randall Stewart. All rights reserved.
 * Copyright (c) 2008-2012, by Michael Tuexen. All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *
 * a) Redistributions of source code must retain the above copyright notice,
 *    this list of conditions and the following disclaimer.
 *
 * b) Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in
 *    the documentation and/or other materials provided with the distribution.
 *
 * c) Neither the name of Cisco Systems, Inc. nor the names of its
 *    contributors may be used to endorse or promote products derived
 *    from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
 * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
 * THE POSSIBILITY OF SUCH DAMAGE.
 */
 
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
 
#include <netinet/sctp_os.h>
#include <netinet/sctp.h>
#include <netinet/sctp_header.h>
#include <netinet/sctp_pcb.h>
#include <netinet/sctp_var.h>
#include <netinet/sctp_sysctl.h>
#include <netinet/sctputil.h>
#include <netinet/sctp_indata.h>
#include <netinet/sctp_output.h>
#include <netinet/sctp_auth.h>
 
#ifdef SCTP_DEBUG
#define SCTP_AUTH_DEBUG         (SCTP_BASE_SYSCTL(sctp_debug_on) & SCTP_DEBUG_AUTH1)
#define SCTP_AUTH_DEBUG2        (SCTP_BASE_SYSCTL(sctp_debug_on) & SCTP_DEBUG_AUTH2)
#endif                          /* SCTP_DEBUG */
 
void
sctp_clear_chunklist(sctp_auth_chklist_t *chklist)
{
        memset(chklist, 0, sizeof(*chklist));
        /* chklist->num_chunks = 0; */
}
 
sctp_auth_chklist_t *
sctp_alloc_chunklist(void)
{
        sctp_auth_chklist_t *chklist;
 
        SCTP_MALLOC(chklist, sctp_auth_chklist_t *, sizeof(*chklist),
            SCTP_M_AUTH_CL);
        if (chklist == NULL) {
                SCTPDBG(SCTP_DEBUG_AUTH1, "sctp_alloc_chunklist: failed to get memory!\n");
        } else {
                sctp_clear_chunklist(chklist);
        }
        return (chklist);
}
 
void
sctp_free_chunklist(sctp_auth_chklist_t *list)
{
        if (list != NULL)
                SCTP_FREE(list, SCTP_M_AUTH_CL);
}
 
sctp_auth_chklist_t *
sctp_copy_chunklist(sctp_auth_chklist_t *list)
{
        sctp_auth_chklist_t *new_list;
 
        if (list == NULL)
                return (NULL);
 
        /* get a new list */
        new_list = sctp_alloc_chunklist();
        if (new_list == NULL)
                return (NULL);
        /* copy it */
        memcpy(new_list, list, sizeof(*new_list));
 
        return (new_list);
}
 
/*
 * add a chunk to the required chunks list
 */
int
sctp_auth_add_chunk(uint8_t chunk, sctp_auth_chklist_t *list)
{
        if (list == NULL)
                return (-1);
 
        /* is chunk restricted? */
        if ((chunk == SCTP_INITIATION) ||
            (chunk == SCTP_INITIATION_ACK) ||
            (chunk == SCTP_SHUTDOWN_COMPLETE) ||
            (chunk == SCTP_AUTHENTICATION)) {
                return (-1);
        }
        if (list->chunks[chunk] == 0) {
                list->chunks[chunk] = 1;
                list->num_chunks++;
                SCTPDBG(SCTP_DEBUG_AUTH1,
                    "SCTP: added chunk %u (0x%02x) to Auth list\n",
                    chunk, chunk);
        }
        return (0);
}
 
/*
 * delete a chunk from the required chunks list
 */
int
sctp_auth_delete_chunk(uint8_t chunk, sctp_auth_chklist_t *list)
{
        if (list == NULL)
                return (-1);
 
        if (list->chunks[chunk] == 1) {
                list->chunks[chunk] = 0;
                list->num_chunks--;
                SCTPDBG(SCTP_DEBUG_AUTH1,
                    "SCTP: deleted chunk %u (0x%02x) from Auth list\n",
                    chunk, chunk);
        }
        return (0);
}
 
size_t
sctp_auth_get_chklist_size(const sctp_auth_chklist_t *list)
{
        if (list == NULL)
                return (0);
        else
                return (list->num_chunks);
}
 
/*
 * return the current number and list of required chunks caller must
 * guarantee ptr has space for up to 256 bytes
 */
int
sctp_serialize_auth_chunks(const sctp_auth_chklist_t *list, uint8_t *ptr)
{
        int i, count = 0;
 
        if (list == NULL)
                return (0);
 
        for (i = 0; i < 256; i++) {
                if (list->chunks[i] != 0) {
                        *ptr++ = i;
                        count++;
                }
        }
        return (count);
}
 
int
sctp_pack_auth_chunks(const sctp_auth_chklist_t *list, uint8_t *ptr)
{
        int i, size = 0;
 
        if (list == NULL)
                return (0);
 
        if (list->num_chunks <= 32) {
                /* just list them, one byte each */
                for (i = 0; i < 256; i++) {
                        if (list->chunks[i] != 0) {
                                *ptr++ = i;
                                size++;
                        }
                }
        } else {
                int index, offset;
 
                /* pack into a 32 byte bitfield */
                for (i = 0; i < 256; i++) {
                        if (list->chunks[i] != 0) {
                                index = i / 8;
                                offset = i % 8;
                                ptr[index] |= (1 << offset);
                        }
                }
                size = 32;
        }
        return (size);
}
 
int
sctp_unpack_auth_chunks(const uint8_t *ptr, uint8_t num_chunks,
    sctp_auth_chklist_t *list)
{
        int i;
        int size;
 
        if (list == NULL)
                return (0);
 
        if (num_chunks <= 32) {
                /* just pull them, one byte each */
                for (i = 0; i < num_chunks; i++) {
                        (void)sctp_auth_add_chunk(*ptr++, list);
                }
                size = num_chunks;
        } else {
                int index, offset;
 
                /* unpack from a 32 byte bitfield */
                for (index = 0; index < 32; index++) {
                        for (offset = 0; offset < 8; offset++) {
                                if (ptr[index] & (1 << offset)) {
                                        (void)sctp_auth_add_chunk((index * 8) + offset, list);
                                }
                        }
                }
                size = 32;
        }
        return (size);
}
 
/*
 * allocate structure space for a key of length keylen
 */
sctp_key_t *
sctp_alloc_key(uint32_t keylen)
{
        sctp_key_t *new_key;
 
        SCTP_MALLOC(new_key, sctp_key_t *, sizeof(*new_key) + keylen,
            SCTP_M_AUTH_KY);
        if (new_key == NULL) {
                /* out of memory */
                return (NULL);
        }
        new_key->keylen = keylen;
        return (new_key);
}
 
void
sctp_free_key(sctp_key_t *key)
{
        if (key != NULL)
                SCTP_FREE(key, SCTP_M_AUTH_KY);
}
 
void
sctp_print_key(sctp_key_t *key, const char *str)
{
        uint32_t i;
 
        if (key == NULL) {
                SCTP_PRINTF("%s: [Null key]\n", str);
                return;
        }
        SCTP_PRINTF("%s: len %u, ", str, key->keylen);
        if (key->keylen) {
                for (i = 0; i < key->keylen; i++)
                        SCTP_PRINTF("%02x", key->key[i]);
                SCTP_PRINTF("\n");
        } else {
                SCTP_PRINTF("[Null key]\n");
        }
}
 
void
sctp_show_key(sctp_key_t *key, const char *str)
{
        uint32_t i;
 
        if (key == NULL) {
                SCTP_PRINTF("%s: [Null key]\n", str);
                return;
        }
        SCTP_PRINTF("%s: len %u, ", str, key->keylen);
        if (key->keylen) {
                for (i = 0; i < key->keylen; i++)
                        SCTP_PRINTF("%02x", key->key[i]);
                SCTP_PRINTF("\n");
        } else {
                SCTP_PRINTF("[Null key]\n");
        }
}
 
static uint32_t
sctp_get_keylen(sctp_key_t *key)
{
        if (key != NULL)
                return (key->keylen);
        else
                return (0);
}
 
/*
 * generate a new random key of length 'keylen'
 */
sctp_key_t *
sctp_generate_random_key(uint32_t keylen)
{
        sctp_key_t *new_key;
 
        new_key = sctp_alloc_key(keylen);
        if (new_key == NULL) {
                /* out of memory */
                return (NULL);
        }
        SCTP_READ_RANDOM(new_key->key, keylen);
        new_key->keylen = keylen;
        return (new_key);
}
 
sctp_key_t *
sctp_set_key(uint8_t *key, uint32_t keylen)
{
        sctp_key_t *new_key;
 
        new_key = sctp_alloc_key(keylen);
        if (new_key == NULL) {
                /* out of memory */
                return (NULL);
        }
        memcpy(new_key->key, key, keylen);
        return (new_key);
}
 
/*-
 * given two keys of variable size, compute which key is "larger/smaller"
 * returns:  1 if key1 > key2
 *          -1 if key1 < key2
 *           0 if key1 = key2
 */
static int
sctp_compare_key(sctp_key_t *key1, sctp_key_t *key2)
{
        uint32_t maxlen;
        uint32_t i;
        uint32_t key1len, key2len;
        uint8_t *key_1, *key_2;
        uint8_t val1, val2;
 
        /* sanity/length check */
        key1len = sctp_get_keylen(key1);
        key2len = sctp_get_keylen(key2);
        if ((key1len == 0) && (key2len == 0))
                return (0);
        else if (key1len == 0)
                return (-1);
        else if (key2len == 0)
                return (1);
 
        if (key1len < key2len) {
                maxlen = key2len;
        } else {
                maxlen = key1len;
        }
        key_1 = key1->key;
        key_2 = key2->key;
        /* check for numeric equality */
        for (i = 0; i < maxlen; i++) {
                /* left-pad with zeros */
                val1 = (i < (maxlen - key1len)) ? 0 : *(key_1++);
                val2 = (i < (maxlen - key2len)) ? 0 : *(key_2++);
                if (val1 > val2) {
                        return (1);
                } else if (val1 < val2) {
                        return (-1);
                }
        }
        /* keys are equal value, so check lengths */
        if (key1len == key2len)
                return (0);
        else if (key1len < key2len)
                return (-1);
        else
                return (1);
}
 
/*
 * generate the concatenated keying material based on the two keys and the
 * shared key (if available). draft-ietf-tsvwg-auth specifies the specific
 * order for concatenation
 */
sctp_key_t *
sctp_compute_hashkey(sctp_key_t *key1, sctp_key_t *key2, sctp_key_t *shared)
{
        uint32_t keylen;
        sctp_key_t *new_key;
        uint8_t *key_ptr;
 
        keylen = sctp_get_keylen(key1) + sctp_get_keylen(key2) +
            sctp_get_keylen(shared);
 
        if (keylen > 0) {
                /* get space for the new key */
                new_key = sctp_alloc_key(keylen);
                if (new_key == NULL) {
                        /* out of memory */
                        return (NULL);
                }
                new_key->keylen = keylen;
                key_ptr = new_key->key;
        } else {
                /* all keys empty/null?! */
                return (NULL);
        }
 
        /* concatenate the keys */
        if (sctp_compare_key(key1, key2) <= 0) {
                /* key is shared + key1 + key2 */
                if (sctp_get_keylen(shared)) {
                        memcpy(key_ptr, shared->key, shared->keylen);
                        key_ptr += shared->keylen;
                }
                if (sctp_get_keylen(key1)) {
                        memcpy(key_ptr, key1->key, key1->keylen);
                        key_ptr += key1->keylen;
                }
                if (sctp_get_keylen(key2)) {
                        memcpy(key_ptr, key2->key, key2->keylen);
                }
        } else {
                /* key is shared + key2 + key1 */
                if (sctp_get_keylen(shared)) {
                        memcpy(key_ptr, shared->key, shared->keylen);
                        key_ptr += shared->keylen;
                }
                if (sctp_get_keylen(key2)) {
                        memcpy(key_ptr, key2->key, key2->keylen);
                        key_ptr += key2->keylen;
                }
                if (sctp_get_keylen(key1)) {
                        memcpy(key_ptr, key1->key, key1->keylen);
                }
        }
        return (new_key);
}
 
sctp_sharedkey_t *
sctp_alloc_sharedkey(void)
{
        sctp_sharedkey_t *new_key;
 
        SCTP_MALLOC(new_key, sctp_sharedkey_t *, sizeof(*new_key),
            SCTP_M_AUTH_KY);
        if (new_key == NULL) {
                /* out of memory */
                return (NULL);
        }
        new_key->keyid = 0;
        new_key->key = NULL;
        new_key->refcount = 1;
        new_key->deactivated = 0;
        return (new_key);
}
 
void
sctp_free_sharedkey(sctp_sharedkey_t *skey)
{
        if (skey == NULL)
                return;
 
        if (SCTP_DECREMENT_AND_CHECK_REFCOUNT(&skey->refcount)) {
                if (skey->key != NULL)
                        sctp_free_key(skey->key);
                SCTP_FREE(skey, SCTP_M_AUTH_KY);
        }
}
 
sctp_sharedkey_t *
sctp_find_sharedkey(struct sctp_keyhead *shared_keys, uint16_t key_id)
{
        sctp_sharedkey_t *skey;
 
        LIST_FOREACH(skey, shared_keys, next) {
                if (skey->keyid == key_id)
                        return (skey);
        }
        return (NULL);
}
 
int
sctp_insert_sharedkey(struct sctp_keyhead *shared_keys,
    sctp_sharedkey_t *new_skey)
{
        sctp_sharedkey_t *skey;
 
        if ((shared_keys == NULL) || (new_skey == NULL))
                return (EINVAL);
 
        /* insert into an empty list? */
        if (LIST_EMPTY(shared_keys)) {
                LIST_INSERT_HEAD(shared_keys, new_skey, next);
                return (0);
        }
        /* insert into the existing list, ordered by key id */
        LIST_FOREACH(skey, shared_keys, next) {
                if (new_skey->keyid < skey->keyid) {
                        /* insert it before here */
                        LIST_INSERT_BEFORE(skey, new_skey, next);
                        return (0);
                } else if (new_skey->keyid == skey->keyid) {
                        /* replace the existing key */
                        /* verify this key *can* be replaced */
                        if ((skey->deactivated) || (skey->refcount > 1)) {
                                SCTPDBG(SCTP_DEBUG_AUTH1,
                                    "can't replace shared key id %u\n",
                                    new_skey->keyid);
                                return (EBUSY);
                        }
                        SCTPDBG(SCTP_DEBUG_AUTH1,
                            "replacing shared key id %u\n",
                            new_skey->keyid);
                        LIST_INSERT_BEFORE(skey, new_skey, next);
                        LIST_REMOVE(skey, next);
                        sctp_free_sharedkey(skey);
                        return (0);
                }
                if (LIST_NEXT(skey, next) == NULL) {
                        /* belongs at the end of the list */
                        LIST_INSERT_AFTER(skey, new_skey, next);
                        return (0);
                }
        }
        /* shouldn't reach here */
        return (EINVAL);
}
 
void
sctp_auth_key_acquire(struct sctp_tcb *stcb, uint16_t key_id)
{
        sctp_sharedkey_t *skey;
 
        /* find the shared key */
        skey = sctp_find_sharedkey(&stcb->asoc.shared_keys, key_id);
 
        /* bump the ref count */
        if (skey) {
                atomic_add_int(&skey->refcount, 1);
                SCTPDBG(SCTP_DEBUG_AUTH2,
                    "%s: stcb %p key %u refcount acquire to %d\n",
                    __func__, (void *)stcb, key_id, skey->refcount);
        }
}
 
void
sctp_auth_key_release(struct sctp_tcb *stcb, uint16_t key_id, int so_locked)
{
        sctp_sharedkey_t *skey;
 
        /* find the shared key */
        skey = sctp_find_sharedkey(&stcb->asoc.shared_keys, key_id);
 
        /* decrement the ref count */
        if (skey) {
                SCTPDBG(SCTP_DEBUG_AUTH2,
                    "%s: stcb %p key %u refcount release to %d\n",
                    __func__, (void *)stcb, key_id, skey->refcount);
 
                /* see if a notification should be generated */
                if ((skey->refcount <= 2) && (skey->deactivated)) {
                        /* notify ULP that key is no longer used */
                        sctp_ulp_notify(SCTP_NOTIFY_AUTH_FREE_KEY, stcb,
                            key_id, 0, so_locked);
                        SCTPDBG(SCTP_DEBUG_AUTH2,
                            "%s: stcb %p key %u no longer used, %d\n",
                            __func__, (void *)stcb, key_id, skey->refcount);
                }
                sctp_free_sharedkey(skey);
        }
}
 
static sctp_sharedkey_t *
sctp_copy_sharedkey(const sctp_sharedkey_t *skey)
{
        sctp_sharedkey_t *new_skey;
 
        if (skey == NULL)
                return (NULL);
        new_skey = sctp_alloc_sharedkey();
        if (new_skey == NULL)
                return (NULL);
        if (skey->key != NULL)
                new_skey->key = sctp_set_key(skey->key->key, skey->key->keylen);
        else
                new_skey->key = NULL;
        new_skey->keyid = skey->keyid;
        return (new_skey);
}
 
int
sctp_copy_skeylist(const struct sctp_keyhead *src, struct sctp_keyhead *dest)
{
        sctp_sharedkey_t *skey, *new_skey;
        int count = 0;
 
        if ((src == NULL) || (dest == NULL))
                return (0);
        LIST_FOREACH(skey, src, next) {
                new_skey = sctp_copy_sharedkey(skey);
                if (new_skey != NULL) {
                        if (sctp_insert_sharedkey(dest, new_skey)) {
                                sctp_free_sharedkey(new_skey);
                        } else {
                                count++;
                        }
                }
        }
        return (count);
}
 
sctp_hmaclist_t *
sctp_alloc_hmaclist(uint16_t num_hmacs)
{
        sctp_hmaclist_t *new_list;
        int alloc_size;
 
        alloc_size = sizeof(*new_list) + num_hmacs * sizeof(new_list->hmac[0]);
        SCTP_MALLOC(new_list, sctp_hmaclist_t *, alloc_size,
            SCTP_M_AUTH_HL);
        if (new_list == NULL) {
                /* out of memory */
                return (NULL);
        }
        new_list->max_algo = num_hmacs;
        new_list->num_algo = 0;
        return (new_list);
}
 
void
sctp_free_hmaclist(sctp_hmaclist_t *list)
{
        if (list != NULL) {
                SCTP_FREE(list, SCTP_M_AUTH_HL);
        }
}
 
int
sctp_auth_add_hmacid(sctp_hmaclist_t *list, uint16_t hmac_id)
{
        int i;
 
        if (list == NULL)
                return (-1);
        if (list->num_algo == list->max_algo) {
                SCTPDBG(SCTP_DEBUG_AUTH1,
                    "SCTP: HMAC id list full, ignoring add %u\n", hmac_id);
                return (-1);
        }
        if ((hmac_id != SCTP_AUTH_HMAC_ID_SHA1) &&
            (hmac_id != SCTP_AUTH_HMAC_ID_SHA256)) {
                return (-1);
        }
        /* Now is it already in the list */
        for (i = 0; i < list->num_algo; i++) {
                if (list->hmac[i] == hmac_id) {
                        /* already in list */
                        return (-1);
                }
        }
        SCTPDBG(SCTP_DEBUG_AUTH1, "SCTP: add HMAC id %u to list\n", hmac_id);
        list->hmac[list->num_algo++] = hmac_id;
        return (0);
}
 
sctp_hmaclist_t *
sctp_copy_hmaclist(sctp_hmaclist_t *list)
{
        sctp_hmaclist_t *new_list;
        int i;
 
        if (list == NULL)
                return (NULL);
        /* get a new list */
        new_list = sctp_alloc_hmaclist(list->max_algo);
        if (new_list == NULL)
                return (NULL);
        /* copy it */
        new_list->max_algo = list->max_algo;
        new_list->num_algo = list->num_algo;
        for (i = 0; i < list->num_algo; i++)
                new_list->hmac[i] = list->hmac[i];
        return (new_list);
}
 
sctp_hmaclist_t *
sctp_default_supported_hmaclist(void)
{
        sctp_hmaclist_t *new_list;
 
        new_list = sctp_alloc_hmaclist(2);
        if (new_list == NULL)
                return (NULL);
        /* We prefer SHA256, so list it first */
        (void)sctp_auth_add_hmacid(new_list, SCTP_AUTH_HMAC_ID_SHA256);
        (void)sctp_auth_add_hmacid(new_list, SCTP_AUTH_HMAC_ID_SHA1);
        return (new_list);
}
 
/*-
 * HMAC algos are listed in priority/preference order
 * find the best HMAC id to use for the peer based on local support
 */
uint16_t
sctp_negotiate_hmacid(sctp_hmaclist_t *peer, sctp_hmaclist_t *local)
{
        int i, j;
 
        if ((local == NULL) || (peer == NULL))
                return (SCTP_AUTH_HMAC_ID_RSVD);
 
        for (i = 0; i < peer->num_algo; i++) {
                for (j = 0; j < local->num_algo; j++) {
                        if (peer->hmac[i] == local->hmac[j]) {
                                /* found the "best" one */
                                SCTPDBG(SCTP_DEBUG_AUTH1,
                                    "SCTP: negotiated peer HMAC id %u\n",
                                    peer->hmac[i]);
                                return (peer->hmac[i]);
                        }
                }
        }
        /* didn't find one! */
        return (SCTP_AUTH_HMAC_ID_RSVD);
}
 
/*-
 * serialize the HMAC algo list and return space used
 * caller must guarantee ptr has appropriate space
 */
int
sctp_serialize_hmaclist(sctp_hmaclist_t *list, uint8_t *ptr)
{
        int i;
        uint16_t hmac_id;
 
        if (list == NULL)
                return (0);
 
        for (i = 0; i < list->num_algo; i++) {
                hmac_id = htons(list->hmac[i]);
                memcpy(ptr, &hmac_id, sizeof(hmac_id));
                ptr += sizeof(hmac_id);
        }
        return (list->num_algo * sizeof(hmac_id));
}
 
int
sctp_verify_hmac_param(struct sctp_auth_hmac_algo *hmacs, uint32_t num_hmacs)
{
        uint32_t i;
 
        for (i = 0; i < num_hmacs; i++) {
                if (ntohs(hmacs->hmac_ids[i]) == SCTP_AUTH_HMAC_ID_SHA1) {
                        return (0);
                }
        }
        return (-1);
}
 
sctp_authinfo_t *
sctp_alloc_authinfo(void)
{
        sctp_authinfo_t *new_authinfo;
 
        SCTP_MALLOC(new_authinfo, sctp_authinfo_t *, sizeof(*new_authinfo),
            SCTP_M_AUTH_IF);
 
        if (new_authinfo == NULL) {
                /* out of memory */
                return (NULL);
        }
        memset(new_authinfo, 0, sizeof(*new_authinfo));
        return (new_authinfo);
}
 
void
sctp_free_authinfo(sctp_authinfo_t *authinfo)
{
        if (authinfo == NULL)
                return;
 
        if (authinfo->random != NULL)
                sctp_free_key(authinfo->random);
        if (authinfo->peer_random != NULL)
                sctp_free_key(authinfo->peer_random);
        if (authinfo->assoc_key != NULL)
                sctp_free_key(authinfo->assoc_key);
        if (authinfo->recv_key != NULL)
                sctp_free_key(authinfo->recv_key);
 
        /* We are NOT dynamically allocating authinfo's right now... */
        /* SCTP_FREE(authinfo, SCTP_M_AUTH_??); */
}
 
uint32_t
sctp_get_auth_chunk_len(uint16_t hmac_algo)
{
        int size;
 
        size = sizeof(struct sctp_auth_chunk) + sctp_get_hmac_digest_len(hmac_algo);
        return (SCTP_SIZE32(size));
}
 
uint32_t
sctp_get_hmac_digest_len(uint16_t hmac_algo)
{
        switch (hmac_algo) {
        case SCTP_AUTH_HMAC_ID_SHA1:
                return (SCTP_AUTH_DIGEST_LEN_SHA1);
        case SCTP_AUTH_HMAC_ID_SHA256:
                return (SCTP_AUTH_DIGEST_LEN_SHA256);
        default:
                /* unknown HMAC algorithm: can't do anything */
                return (0);
        }                       /* end switch */
}
 
static inline int
sctp_get_hmac_block_len(uint16_t hmac_algo)
{
        switch (hmac_algo) {
        case SCTP_AUTH_HMAC_ID_SHA1:
                return (64);
        case SCTP_AUTH_HMAC_ID_SHA256:
                return (64);
        case SCTP_AUTH_HMAC_ID_RSVD:
        default:
                /* unknown HMAC algorithm: can't do anything */
                return (0);
        }                       /* end switch */
}
 
static void
sctp_hmac_init(uint16_t hmac_algo, sctp_hash_context_t *ctx)
{
        switch (hmac_algo) {
        case SCTP_AUTH_HMAC_ID_SHA1:
                SCTP_SHA1_INIT(&ctx->sha1);
                break;
        case SCTP_AUTH_HMAC_ID_SHA256:
                SCTP_SHA256_INIT(&ctx->sha256);
                break;
        case SCTP_AUTH_HMAC_ID_RSVD:
        default:
                /* unknown HMAC algorithm: can't do anything */
                return;
        }                       /* end switch */
}
 
static void
sctp_hmac_update(uint16_t hmac_algo, sctp_hash_context_t *ctx,
    uint8_t *text, uint32_t textlen)
{
        switch (hmac_algo) {
        case SCTP_AUTH_HMAC_ID_SHA1:
                SCTP_SHA1_UPDATE(&ctx->sha1, text, textlen);
                break;
        case SCTP_AUTH_HMAC_ID_SHA256:
                SCTP_SHA256_UPDATE(&ctx->sha256, text, textlen);
                break;
        case SCTP_AUTH_HMAC_ID_RSVD:
        default:
                /* unknown HMAC algorithm: can't do anything */
                return;
        }                       /* end switch */
}
 
static void
sctp_hmac_final(uint16_t hmac_algo, sctp_hash_context_t *ctx,
    uint8_t *digest)
{
        switch (hmac_algo) {
        case SCTP_AUTH_HMAC_ID_SHA1:
                SCTP_SHA1_FINAL(digest, &ctx->sha1);
                break;
        case SCTP_AUTH_HMAC_ID_SHA256:
                SCTP_SHA256_FINAL(digest, &ctx->sha256);
                break;
        case SCTP_AUTH_HMAC_ID_RSVD:
        default:
                /* unknown HMAC algorithm: can't do anything */
                return;
        }                       /* end switch */
}
 
/*-
 * Keyed-Hashing for Message Authentication: FIPS 198 (RFC 2104)
 *
 * Compute the HMAC digest using the desired hash key, text, and HMAC
 * algorithm.  Resulting digest is placed in 'digest' and digest length
 * is returned, if the HMAC was performed.
 *
 * WARNING: it is up to the caller to supply sufficient space to hold the
 * resultant digest.
 */
uint32_t
sctp_hmac(uint16_t hmac_algo, uint8_t *key, uint32_t keylen,
    uint8_t *text, uint32_t textlen, uint8_t *digest)
{
        uint32_t digestlen;
        uint32_t blocklen;
        sctp_hash_context_t ctx;
        uint8_t ipad[128], opad[128];   /* keyed hash inner/outer pads */
        uint8_t temp[SCTP_AUTH_DIGEST_LEN_MAX];
        uint32_t i;
 
        /* sanity check the material and length */
        if ((key == NULL) || (keylen == 0) || (text == NULL) ||
            (textlen == 0) || (digest == NULL)) {
                /* can't do HMAC with empty key or text or digest store */
                return (0);
        }
        /* validate the hmac algo and get the digest length */
        digestlen = sctp_get_hmac_digest_len(hmac_algo);
        if (digestlen == 0)
                return (0);
 
        /* hash the key if it is longer than the hash block size */
        blocklen = sctp_get_hmac_block_len(hmac_algo);
        if (keylen > blocklen) {
                sctp_hmac_init(hmac_algo, &ctx);
                sctp_hmac_update(hmac_algo, &ctx, key, keylen);
                sctp_hmac_final(hmac_algo, &ctx, temp);
                /* set the hashed key as the key */
                keylen = digestlen;
                key = temp;
        }
        /* initialize the inner/outer pads with the key and "append" zeroes */
        memset(ipad, 0, blocklen);
        memset(opad, 0, blocklen);
        memcpy(ipad, key, keylen);
        memcpy(opad, key, keylen);
 
        /* XOR the key with ipad and opad values */
        for (i = 0; i < blocklen; i++) {
                ipad[i] ^= 0x36;
                opad[i] ^= 0x5c;
        }
 
        /* perform inner hash */
        sctp_hmac_init(hmac_algo, &ctx);
        sctp_hmac_update(hmac_algo, &ctx, ipad, blocklen);
        sctp_hmac_update(hmac_algo, &ctx, text, textlen);
        sctp_hmac_final(hmac_algo, &ctx, temp);
 
        /* perform outer hash */
        sctp_hmac_init(hmac_algo, &ctx);
        sctp_hmac_update(hmac_algo, &ctx, opad, blocklen);
        sctp_hmac_update(hmac_algo, &ctx, temp, digestlen);
        sctp_hmac_final(hmac_algo, &ctx, digest);
 
        return (digestlen);
}
 
/* mbuf version */
uint32_t
sctp_hmac_m(uint16_t hmac_algo, uint8_t *key, uint32_t keylen,
    struct mbuf *m, uint32_t m_offset, uint8_t *digest, uint32_t trailer)
{
        uint32_t digestlen;
        uint32_t blocklen;
        sctp_hash_context_t ctx;
        uint8_t ipad[128], opad[128];   /* keyed hash inner/outer pads */
        uint8_t temp[SCTP_AUTH_DIGEST_LEN_MAX];
        uint32_t i;
        struct mbuf *m_tmp;
 
        /* sanity check the material and length */
        if ((key == NULL) || (keylen == 0) || (m == NULL) || (digest == NULL)) {
                /* can't do HMAC with empty key or text or digest store */
                return (0);
        }
        /* validate the hmac algo and get the digest length */
        digestlen = sctp_get_hmac_digest_len(hmac_algo);
        if (digestlen == 0)
                return (0);
 
        /* hash the key if it is longer than the hash block size */
        blocklen = sctp_get_hmac_block_len(hmac_algo);
        if (keylen > blocklen) {
                sctp_hmac_init(hmac_algo, &ctx);
                sctp_hmac_update(hmac_algo, &ctx, key, keylen);
                sctp_hmac_final(hmac_algo, &ctx, temp);
                /* set the hashed key as the key */
                keylen = digestlen;
                key = temp;
        }
        /* initialize the inner/outer pads with the key and "append" zeroes */
        memset(ipad, 0, blocklen);
        memset(opad, 0, blocklen);
        memcpy(ipad, key, keylen);
        memcpy(opad, key, keylen);
 
        /* XOR the key with ipad and opad values */
        for (i = 0; i < blocklen; i++) {
                ipad[i] ^= 0x36;
                opad[i] ^= 0x5c;
        }
 
        /* perform inner hash */
        sctp_hmac_init(hmac_algo, &ctx);
        sctp_hmac_update(hmac_algo, &ctx, ipad, blocklen);
        /* find the correct starting mbuf and offset (get start of text) */
        m_tmp = m;
        while ((m_tmp != NULL) && (m_offset >= (uint32_t)SCTP_BUF_LEN(m_tmp))) {
                m_offset -= SCTP_BUF_LEN(m_tmp);
                m_tmp = SCTP_BUF_NEXT(m_tmp);
        }
        /* now use the rest of the mbuf chain for the text */
        while (m_tmp != NULL) {
                if ((SCTP_BUF_NEXT(m_tmp) == NULL) && trailer) {
                        sctp_hmac_update(hmac_algo, &ctx, mtod(m_tmp, uint8_t *)+m_offset,
                            SCTP_BUF_LEN(m_tmp) - (trailer + m_offset));
                } else {
                        sctp_hmac_update(hmac_algo, &ctx, mtod(m_tmp, uint8_t *)+m_offset,
                            SCTP_BUF_LEN(m_tmp) - m_offset);
                }
 
                /* clear the offset since it's only for the first mbuf */
                m_offset = 0;
                m_tmp = SCTP_BUF_NEXT(m_tmp);
        }
        sctp_hmac_final(hmac_algo, &ctx, temp);
 
        /* perform outer hash */
        sctp_hmac_init(hmac_algo, &ctx);
        sctp_hmac_update(hmac_algo, &ctx, opad, blocklen);
        sctp_hmac_update(hmac_algo, &ctx, temp, digestlen);
        sctp_hmac_final(hmac_algo, &ctx, digest);
 
        return (digestlen);
}
 
/*
 * computes the requested HMAC using a key struct (which may be modified if
 * the keylen exceeds the HMAC block len).
 */
uint32_t
sctp_compute_hmac(uint16_t hmac_algo, sctp_key_t *key, uint8_t *text,
    uint32_t textlen, uint8_t *digest)
{
        uint32_t digestlen;
        uint32_t blocklen;
        sctp_hash_context_t ctx;
        uint8_t temp[SCTP_AUTH_DIGEST_LEN_MAX];
 
        /* sanity check */
        if ((key == NULL) || (text == NULL) || (textlen == 0) ||
            (digest == NULL)) {
                /* can't do HMAC with empty key or text or digest store */
                return (0);
        }
        /* validate the hmac algo and get the digest length */
        digestlen = sctp_get_hmac_digest_len(hmac_algo);
        if (digestlen == 0)
                return (0);
 
        /* hash the key if it is longer than the hash block size */
        blocklen = sctp_get_hmac_block_len(hmac_algo);
        if (key->keylen > blocklen) {
                sctp_hmac_init(hmac_algo, &ctx);
                sctp_hmac_update(hmac_algo, &ctx, key->key, key->keylen);
                sctp_hmac_final(hmac_algo, &ctx, temp);
                /* save the hashed key as the new key */
                key->keylen = digestlen;
                memcpy(key->key, temp, key->keylen);
        }
        return (sctp_hmac(hmac_algo, key->key, key->keylen, text, textlen,
            digest));
}
 
/* mbuf version */
uint32_t
sctp_compute_hmac_m(uint16_t hmac_algo, sctp_key_t *key, struct mbuf *m,
    uint32_t m_offset, uint8_t *digest)
{
        uint32_t digestlen;
        uint32_t blocklen;
        sctp_hash_context_t ctx;
        uint8_t temp[SCTP_AUTH_DIGEST_LEN_MAX];
 
        /* sanity check */
        if ((key == NULL) || (m == NULL) || (digest == NULL)) {
                /* can't do HMAC with empty key or text or digest store */
                return (0);
        }
        /* validate the hmac algo and get the digest length */
        digestlen = sctp_get_hmac_digest_len(hmac_algo);
        if (digestlen == 0)
                return (0);
 
        /* hash the key if it is longer than the hash block size */
        blocklen = sctp_get_hmac_block_len(hmac_algo);
        if (key->keylen > blocklen) {
                sctp_hmac_init(hmac_algo, &ctx);
                sctp_hmac_update(hmac_algo, &ctx, key->key, key->keylen);
                sctp_hmac_final(hmac_algo, &ctx, temp);
                /* save the hashed key as the new key */
                key->keylen = digestlen;
                memcpy(key->key, temp, key->keylen);
        }
        return (sctp_hmac_m(hmac_algo, key->key, key->keylen, m, m_offset, digest, 0));
}
 
int
sctp_auth_is_supported_hmac(sctp_hmaclist_t *list, uint16_t id)
{
        int i;
 
        if ((list == NULL) || (id == SCTP_AUTH_HMAC_ID_RSVD))
                return (0);
 
        for (i = 0; i < list->num_algo; i++)
                if (list->hmac[i] == id)
                        return (1);
 
        /* not in the list */
        return (0);
}
 
/*-
 * clear any cached key(s) if they match the given key id on an association.
 * the cached key(s) will be recomputed and re-cached at next use.
 * ASSUMES TCB_LOCK is already held
 */
void
sctp_clear_cachedkeys(struct sctp_tcb *stcb, uint16_t keyid)
{
        if (stcb == NULL)
                return;
 
        if (keyid == stcb->asoc.authinfo.assoc_keyid) {
                sctp_free_key(stcb->asoc.authinfo.assoc_key);
                stcb->asoc.authinfo.assoc_key = NULL;
        }
        if (keyid == stcb->asoc.authinfo.recv_keyid) {
                sctp_free_key(stcb->asoc.authinfo.recv_key);
                stcb->asoc.authinfo.recv_key = NULL;
        }
}
 
/*-
 * clear any cached key(s) if they match the given key id for all assocs on
 * an endpoint.
 * ASSUMES INP_WLOCK is already held
 */
void
sctp_clear_cachedkeys_ep(struct sctp_inpcb *inp, uint16_t keyid)
{
        struct sctp_tcb *stcb;
 
        if (inp == NULL)
                return;
 
        /* clear the cached keys on all assocs on this instance */
        LIST_FOREACH(stcb, &inp->sctp_asoc_list, sctp_tcblist) {
                SCTP_TCB_LOCK(stcb);
                sctp_clear_cachedkeys(stcb, keyid);
                SCTP_TCB_UNLOCK(stcb);
        }
}
 
/*-
 * delete a shared key from an association
 * ASSUMES TCB_LOCK is already held
 */
int
sctp_delete_sharedkey(struct sctp_tcb *stcb, uint16_t keyid)
{
        sctp_sharedkey_t *skey;
 
        if (stcb == NULL)
                return (-1);
 
        /* is the keyid the assoc active sending key */
        if (keyid == stcb->asoc.authinfo.active_keyid)
                return (-1);
 
        /* does the key exist? */
        skey = sctp_find_sharedkey(&stcb->asoc.shared_keys, keyid);
        if (skey == NULL)
                return (-1);
 
        /* are there other refcount holders on the key? */
        if (skey->refcount > 1)
                return (-1);
 
        /* remove it */
        LIST_REMOVE(skey, next);
        sctp_free_sharedkey(skey);      /* frees skey->key as well */
 
        /* clear any cached keys */
        sctp_clear_cachedkeys(stcb, keyid);
        return (0);
}
 
/*-
 * deletes a shared key from the endpoint
 * ASSUMES INP_WLOCK is already held
 */
int
sctp_delete_sharedkey_ep(struct sctp_inpcb *inp, uint16_t keyid)
{
        sctp_sharedkey_t *skey;
 
        if (inp == NULL)
                return (-1);
 
        /* is the keyid the active sending key on the endpoint */
        if (keyid == inp->sctp_ep.default_keyid)
                return (-1);
 
        /* does the key exist? */
        skey = sctp_find_sharedkey(&inp->sctp_ep.shared_keys, keyid);
        if (skey == NULL)
                return (-1);
 
        /* endpoint keys are not refcounted */
 
        /* remove it */
        LIST_REMOVE(skey, next);
        sctp_free_sharedkey(skey);      /* frees skey->key as well */
 
        /* clear any cached keys */
        sctp_clear_cachedkeys_ep(inp, keyid);
        return (0);
}
 
/*-
 * set the active key on an association
 * ASSUMES TCB_LOCK is already held
 */
int
sctp_auth_setactivekey(struct sctp_tcb *stcb, uint16_t keyid)
{
        sctp_sharedkey_t *skey = NULL;
 
        /* find the key on the assoc */
        skey = sctp_find_sharedkey(&stcb->asoc.shared_keys, keyid);
        if (skey == NULL) {
                /* that key doesn't exist */
                return (-1);
        }
        if ((skey->deactivated) && (skey->refcount > 1)) {
                /* can't reactivate a deactivated key with other refcounts */
                return (-1);
        }
 
        /* set the (new) active key */
        stcb->asoc.authinfo.active_keyid = keyid;
        /* reset the deactivated flag */
        skey->deactivated = 0;
 
        return (0);
}
 
/*-
 * set the active key on an endpoint
 * ASSUMES INP_WLOCK is already held
 */
int
sctp_auth_setactivekey_ep(struct sctp_inpcb *inp, uint16_t keyid)
{
        sctp_sharedkey_t *skey;
 
        /* find the key */
        skey = sctp_find_sharedkey(&inp->sctp_ep.shared_keys, keyid);
        if (skey == NULL) {
                /* that key doesn't exist */
                return (-1);
        }
        inp->sctp_ep.default_keyid = keyid;
        return (0);
}
 
/*-
 * deactivates a shared key from the association
 * ASSUMES INP_WLOCK is already held
 */
int
sctp_deact_sharedkey(struct sctp_tcb *stcb, uint16_t keyid)
{
        sctp_sharedkey_t *skey;
 
        if (stcb == NULL)
                return (-1);
 
        /* is the keyid the assoc active sending key */
        if (keyid == stcb->asoc.authinfo.active_keyid)
                return (-1);
 
        /* does the key exist? */
        skey = sctp_find_sharedkey(&stcb->asoc.shared_keys, keyid);
        if (skey == NULL)
                return (-1);
 
        /* are there other refcount holders on the key? */
        if (skey->refcount == 1) {
                /* no other users, send a notification for this key */
                sctp_ulp_notify(SCTP_NOTIFY_AUTH_FREE_KEY, stcb, keyid, 0,
                    SCTP_SO_LOCKED);
        }
 
        /* mark the key as deactivated */
        skey->deactivated = 1;
 
        return (0);
}
 
/*-
 * deactivates a shared key from the endpoint
 * ASSUMES INP_WLOCK is already held
 */
int
sctp_deact_sharedkey_ep(struct sctp_inpcb *inp, uint16_t keyid)
{
        sctp_sharedkey_t *skey;
 
        if (inp == NULL)
                return (-1);
 
        /* is the keyid the active sending key on the endpoint */
        if (keyid == inp->sctp_ep.default_keyid)
                return (-1);
 
        /* does the key exist? */
        skey = sctp_find_sharedkey(&inp->sctp_ep.shared_keys, keyid);
        if (skey == NULL)
                return (-1);
 
        /* endpoint keys are not refcounted */
 
        /* remove it */
        LIST_REMOVE(skey, next);
        sctp_free_sharedkey(skey);      /* frees skey->key as well */
 
        return (0);
}
 
/*
 * get local authentication parameters from cookie (from INIT-ACK)
 */
void
sctp_auth_get_cookie_params(struct sctp_tcb *stcb, struct mbuf *m,
    uint32_t offset, uint32_t length)
{
        struct sctp_paramhdr *phdr, tmp_param;
        uint16_t plen, ptype;
        uint8_t random_store[SCTP_PARAM_BUFFER_SIZE];
        struct sctp_auth_random *p_random = NULL;
        uint16_t random_len = 0;
        uint8_t hmacs_store[SCTP_PARAM_BUFFER_SIZE];
        struct sctp_auth_hmac_algo *hmacs = NULL;
        uint16_t hmacs_len = 0;
        uint8_t chunks_store[SCTP_PARAM_BUFFER_SIZE];
        struct sctp_auth_chunk_list *chunks = NULL;
        uint16_t num_chunks = 0;
        sctp_key_t *new_key;
        uint32_t keylen;
 
        /* convert to upper bound */
        length += offset;
 
        phdr = (struct sctp_paramhdr *)sctp_m_getptr(m, offset,
            sizeof(struct sctp_paramhdr), (uint8_t *)&tmp_param);
        while (phdr != NULL) {
                ptype = ntohs(phdr->param_type);
                plen = ntohs(phdr->param_length);
 
                if ((plen < sizeof(struct sctp_paramhdr)) ||
                    (offset + plen > length))
                        break;
 
                if (ptype == SCTP_RANDOM) {
                        if (plen > sizeof(random_store))
                                break;
                        phdr = sctp_get_next_param(m, offset,
                            (struct sctp_paramhdr *)random_store, plen);
                        if (phdr == NULL)
                                return;
                        /* save the random and length for the key */
                        p_random = (struct sctp_auth_random *)phdr;
                        random_len = plen - sizeof(*p_random);
                } else if (ptype == SCTP_HMAC_LIST) {
                        uint16_t num_hmacs;
                        uint16_t i;
 
                        if (plen > sizeof(hmacs_store))
                                break;
                        phdr = sctp_get_next_param(m, offset,
                            (struct sctp_paramhdr *)hmacs_store, plen);
                        if (phdr == NULL)
                                return;
                        /* save the hmacs list and num for the key */
                        hmacs = (struct sctp_auth_hmac_algo *)phdr;
                        hmacs_len = plen - sizeof(*hmacs);
                        num_hmacs = hmacs_len / sizeof(hmacs->hmac_ids[0]);
                        if (stcb->asoc.local_hmacs != NULL)
                                sctp_free_hmaclist(stcb->asoc.local_hmacs);
                        stcb->asoc.local_hmacs = sctp_alloc_hmaclist(num_hmacs);
                        if (stcb->asoc.local_hmacs != NULL) {
                                for (i = 0; i < num_hmacs; i++) {
                                        (void)sctp_auth_add_hmacid(stcb->asoc.local_hmacs,
                                            ntohs(hmacs->hmac_ids[i]));
                                }
                        }
                } else if (ptype == SCTP_CHUNK_LIST) {
                        int i;
 
                        if (plen > sizeof(chunks_store))
                                break;
                        phdr = sctp_get_next_param(m, offset,
                            (struct sctp_paramhdr *)chunks_store, plen);
                        if (phdr == NULL)
                                return;
                        chunks = (struct sctp_auth_chunk_list *)phdr;
                        num_chunks = plen - sizeof(*chunks);
                        /* save chunks list and num for the key */
                        if (stcb->asoc.local_auth_chunks != NULL)
                                sctp_clear_chunklist(stcb->asoc.local_auth_chunks);
                        else
                                stcb->asoc.local_auth_chunks = sctp_alloc_chunklist();
                        for (i = 0; i < num_chunks; i++) {
                                (void)sctp_auth_add_chunk(chunks->chunk_types[i],
                                    stcb->asoc.local_auth_chunks);
                        }
                }
                /* get next parameter */
                offset += SCTP_SIZE32(plen);
                if (offset + sizeof(struct sctp_paramhdr) > length)
                        break;
                phdr = (struct sctp_paramhdr *)sctp_m_getptr(m, offset, sizeof(struct sctp_paramhdr),
                    (uint8_t *)&tmp_param);
        }
        /* concatenate the full random key */
        keylen = sizeof(*p_random) + random_len + sizeof(*hmacs) + hmacs_len;
        if (chunks != NULL) {
                keylen += sizeof(*chunks) + num_chunks;
        }
        new_key = sctp_alloc_key(keylen);
        if (new_key != NULL) {
                /* copy in the RANDOM */
                if (p_random != NULL) {
                        keylen = sizeof(*p_random) + random_len;
                        memcpy(new_key->key, p_random, keylen);
                } else {
                        keylen = 0;
                }
                /* append in the AUTH chunks */
                if (chunks != NULL) {
                        memcpy(new_key->key + keylen, chunks,
                            sizeof(*chunks) + num_chunks);
                        keylen += sizeof(*chunks) + num_chunks;
                }
                /* append in the HMACs */
                if (hmacs != NULL) {
                        memcpy(new_key->key + keylen, hmacs,
                            sizeof(*hmacs) + hmacs_len);
                }
        }
        if (stcb->asoc.authinfo.random != NULL)
                sctp_free_key(stcb->asoc.authinfo.random);
        stcb->asoc.authinfo.random = new_key;
        stcb->asoc.authinfo.random_len = random_len;
        sctp_clear_cachedkeys(stcb, stcb->asoc.authinfo.assoc_keyid);
        sctp_clear_cachedkeys(stcb, stcb->asoc.authinfo.recv_keyid);
 
        /* negotiate what HMAC to use for the peer */
        stcb->asoc.peer_hmac_id = sctp_negotiate_hmacid(stcb->asoc.peer_hmacs,
            stcb->asoc.local_hmacs);
 
        /* copy defaults from the endpoint */
        /* FIX ME: put in cookie? */
        stcb->asoc.authinfo.active_keyid = stcb->sctp_ep->sctp_ep.default_keyid;
        /* copy out the shared key list (by reference) from the endpoint */
        (void)sctp_copy_skeylist(&stcb->sctp_ep->sctp_ep.shared_keys,
            &stcb->asoc.shared_keys);
}
 
/*
 * compute and fill in the HMAC digest for a packet
 */
void
sctp_fill_hmac_digest_m(struct mbuf *m, uint32_t auth_offset,
    struct sctp_auth_chunk *auth, struct sctp_tcb *stcb, uint16_t keyid)
{
        uint32_t digestlen;
        sctp_sharedkey_t *skey;
        sctp_key_t *key;
 
        if ((stcb == NULL) || (auth == NULL))
                return;
 
        /* zero the digest + chunk padding */
        digestlen = sctp_get_hmac_digest_len(stcb->asoc.peer_hmac_id);
        memset(auth->hmac, 0, SCTP_SIZE32(digestlen));
 
        /* is the desired key cached? */
        if ((keyid != stcb->asoc.authinfo.assoc_keyid) ||
            (stcb->asoc.authinfo.assoc_key == NULL)) {
                if (stcb->asoc.authinfo.assoc_key != NULL) {
                        /* free the old cached key */
                        sctp_free_key(stcb->asoc.authinfo.assoc_key);
                }
                skey = sctp_find_sharedkey(&stcb->asoc.shared_keys, keyid);
                /* the only way skey is NULL is if null key id 0 is used */
                if (skey != NULL)
                        key = skey->key;
                else
                        key = NULL;
                /* compute a new assoc key and cache it */
                stcb->asoc.authinfo.assoc_key =
                    sctp_compute_hashkey(stcb->asoc.authinfo.random,
                    stcb->asoc.authinfo.peer_random, key);
                stcb->asoc.authinfo.assoc_keyid = keyid;
                SCTPDBG(SCTP_DEBUG_AUTH1, "caching key id %u\n",
                    stcb->asoc.authinfo.assoc_keyid);
#ifdef SCTP_DEBUG
                if (SCTP_AUTH_DEBUG)
                        sctp_print_key(stcb->asoc.authinfo.assoc_key,
                            "Assoc Key");
#endif
        }
 
        /* set in the active key id */
        auth->shared_key_id = htons(keyid);
 
        /* compute and fill in the digest */
        (void)sctp_compute_hmac_m(stcb->asoc.peer_hmac_id, stcb->asoc.authinfo.assoc_key,
            m, auth_offset, auth->hmac);
}
 
static void
sctp_zero_m(struct mbuf *m, uint32_t m_offset, uint32_t size)
{
        struct mbuf *m_tmp;
        uint8_t *data;
 
        /* sanity check */
        if (m == NULL)
                return;
 
        /* find the correct starting mbuf and offset (get start position) */
        m_tmp = m;
        while ((m_tmp != NULL) && (m_offset >= (uint32_t)SCTP_BUF_LEN(m_tmp))) {
                m_offset -= SCTP_BUF_LEN(m_tmp);
                m_tmp = SCTP_BUF_NEXT(m_tmp);
        }
        /* now use the rest of the mbuf chain */
        while ((m_tmp != NULL) && (size > 0)) {
                data = mtod(m_tmp, uint8_t *)+m_offset;
                if (size > (uint32_t)(SCTP_BUF_LEN(m_tmp) - m_offset)) {
                        memset(data, 0, SCTP_BUF_LEN(m_tmp) - m_offset);
                        size -= SCTP_BUF_LEN(m_tmp) - m_offset;
                } else {
                        memset(data, 0, size);
                        size = 0;
                }
                /* clear the offset since it's only for the first mbuf */
                m_offset = 0;
                m_tmp = SCTP_BUF_NEXT(m_tmp);
        }
}
 
/*-
 * process the incoming Authentication chunk
 * return codes:
 *   -1 on any authentication error
 *    0 on authentication verification
 */
int
sctp_handle_auth(struct sctp_tcb *stcb, struct sctp_auth_chunk *auth,
    struct mbuf *m, uint32_t offset)
{
        uint16_t chunklen;
        uint16_t shared_key_id;
        uint16_t hmac_id;
        sctp_sharedkey_t *skey;
        uint32_t digestlen;
        uint8_t digest[SCTP_AUTH_DIGEST_LEN_MAX];
        uint8_t computed_digest[SCTP_AUTH_DIGEST_LEN_MAX];
 
        /* auth is checked for NULL by caller */
        chunklen = ntohs(auth->ch.chunk_length);
        if (chunklen < sizeof(*auth)) {
                SCTP_STAT_INCR(sctps_recvauthfailed);
                return (-1);
        }
        SCTP_STAT_INCR(sctps_recvauth);
 
        /* get the auth params */
        shared_key_id = ntohs(auth->shared_key_id);
        hmac_id = ntohs(auth->hmac_id);
        SCTPDBG(SCTP_DEBUG_AUTH1,
            "SCTP AUTH Chunk: shared key %u, HMAC id %u\n",
            shared_key_id, hmac_id);
 
        /* is the indicated HMAC supported? */
        if (!sctp_auth_is_supported_hmac(stcb->asoc.local_hmacs, hmac_id)) {
                struct mbuf *op_err;
                struct sctp_error_auth_invalid_hmac *cause;
 
                SCTP_STAT_INCR(sctps_recvivalhmacid);
                SCTPDBG(SCTP_DEBUG_AUTH1,
                    "SCTP Auth: unsupported HMAC id %u\n",
                    hmac_id);
                /*
                 * report this in an Error Chunk: Unsupported HMAC
                 * Identifier
                 */
                op_err = sctp_get_mbuf_for_msg(sizeof(struct sctp_error_auth_invalid_hmac),
                    0, M_NOWAIT, 1, MT_HEADER);
                if (op_err != NULL) {
                        /* pre-reserve some space */
                        SCTP_BUF_RESV_UF(op_err, sizeof(struct sctp_chunkhdr));
                        /* fill in the error */
                        cause = mtod(op_err, struct sctp_error_auth_invalid_hmac *);
                        cause->cause.code = htons(SCTP_CAUSE_UNSUPPORTED_HMACID);
                        cause->cause.length = htons(sizeof(struct sctp_error_auth_invalid_hmac));
                        cause->hmac_id = ntohs(hmac_id);
                        SCTP_BUF_LEN(op_err) = sizeof(struct sctp_error_auth_invalid_hmac);
                        /* queue it */
                        sctp_queue_op_err(stcb, op_err);
                }
                return (-1);
        }
        /* get the indicated shared key, if available */
        if ((stcb->asoc.authinfo.recv_key == NULL) ||
            (stcb->asoc.authinfo.recv_keyid != shared_key_id)) {
                /* find the shared key on the assoc first */
                skey = sctp_find_sharedkey(&stcb->asoc.shared_keys,
                    shared_key_id);
                /* if the shared key isn't found, discard the chunk */
                if (skey == NULL) {
                        SCTP_STAT_INCR(sctps_recvivalkeyid);
                        SCTPDBG(SCTP_DEBUG_AUTH1,
                            "SCTP Auth: unknown key id %u\n",
                            shared_key_id);
                        return (-1);
                }
                /* generate a notification if this is a new key id */
                if (stcb->asoc.authinfo.recv_keyid != shared_key_id)
                        /*
                         * sctp_ulp_notify(SCTP_NOTIFY_AUTH_NEW_KEY, stcb,
                         * shared_key_id, (void
                         * *)stcb->asoc.authinfo.recv_keyid);
                         */
                        sctp_notify_authentication(stcb, SCTP_AUTH_NEW_KEY,
                            shared_key_id, stcb->asoc.authinfo.recv_keyid,
                            SCTP_SO_NOT_LOCKED);
                /* compute a new recv assoc key and cache it */
                if (stcb->asoc.authinfo.recv_key != NULL)
                        sctp_free_key(stcb->asoc.authinfo.recv_key);
                stcb->asoc.authinfo.recv_key =
                    sctp_compute_hashkey(stcb->asoc.authinfo.random,
                    stcb->asoc.authinfo.peer_random, skey->key);
                stcb->asoc.authinfo.recv_keyid = shared_key_id;
#ifdef SCTP_DEBUG
                if (SCTP_AUTH_DEBUG)
                        sctp_print_key(stcb->asoc.authinfo.recv_key, "Recv Key");
#endif
        }
        /* validate the digest length */
        digestlen = sctp_get_hmac_digest_len(hmac_id);
        if (chunklen < (sizeof(*auth) + digestlen)) {
                /* invalid digest length */
                SCTP_STAT_INCR(sctps_recvauthfailed);
                SCTPDBG(SCTP_DEBUG_AUTH1,
                    "SCTP Auth: chunk too short for HMAC\n");
                return (-1);
        }
        /* save a copy of the digest, zero the pseudo header, and validate */
        memcpy(digest, auth->hmac, digestlen);
        sctp_zero_m(m, offset + sizeof(*auth), SCTP_SIZE32(digestlen));
        (void)sctp_compute_hmac_m(hmac_id, stcb->asoc.authinfo.recv_key,
            m, offset, computed_digest);
 
        /* compare the computed digest with the one in the AUTH chunk */
        if (timingsafe_bcmp(digest, computed_digest, digestlen) != 0) {
                SCTP_STAT_INCR(sctps_recvauthfailed);
                SCTPDBG(SCTP_DEBUG_AUTH1,
                    "SCTP Auth: HMAC digest check failed\n");
                return (-1);
        }
        return (0);
}
 
/*
 * Generate NOTIFICATION
 */
void
sctp_notify_authentication(struct sctp_tcb *stcb, uint32_t indication,
    uint16_t keyid, uint16_t alt_keyid, int so_locked)
{
        struct mbuf *m_notify;
        struct sctp_authkey_event *auth;
        struct sctp_queued_to_read *control;
 
        if ((stcb == NULL) ||
            (stcb->sctp_ep->sctp_flags & SCTP_PCB_FLAGS_SOCKET_GONE) ||
            (stcb->sctp_ep->sctp_flags & SCTP_PCB_FLAGS_SOCKET_ALLGONE) ||
            (stcb->asoc.state & SCTP_STATE_CLOSED_SOCKET)
            ) {
                /* If the socket is gone we are out of here */
                return;
        }
 
        if (sctp_stcb_is_feature_off(stcb->sctp_ep, stcb, SCTP_PCB_FLAGS_AUTHEVNT))
                /* event not enabled */
                return;
 
        m_notify = sctp_get_mbuf_for_msg(sizeof(struct sctp_authkey_event),
            0, M_NOWAIT, 1, MT_HEADER);
        if (m_notify == NULL)
                /* no space left */
                return;
 
        SCTP_BUF_LEN(m_notify) = 0;
        auth = mtod(m_notify, struct sctp_authkey_event *);
        memset(auth, 0, sizeof(struct sctp_authkey_event));
        auth->auth_type = SCTP_AUTHENTICATION_EVENT;
        auth->auth_flags = 0;
        auth->auth_length = sizeof(*auth);
        auth->auth_keynumber = keyid;
        auth->auth_altkeynumber = alt_keyid;
        auth->auth_indication = indication;
        auth->auth_assoc_id = sctp_get_associd(stcb);
 
        SCTP_BUF_LEN(m_notify) = sizeof(*auth);
        SCTP_BUF_NEXT(m_notify) = NULL;
 
        /* append to socket */
        control = sctp_build_readq_entry(stcb, stcb->asoc.primary_destination,
            0, 0, stcb->asoc.context, 0, 0, 0, m_notify);
        if (control == NULL) {
                /* no memory */
                sctp_m_freem(m_notify);
                return;
        }
        control->length = SCTP_BUF_LEN(m_notify);
        control->spec_flags = M_NOTIFICATION;
        /* not that we need this */
        control->tail_mbuf = m_notify;
        sctp_add_to_readq(stcb->sctp_ep, stcb, control,
            &stcb->sctp_socket->so_rcv, 1, SCTP_READ_LOCK_NOT_HELD, so_locked);
}
 
/*-
 * validates the AUTHentication related parameters in an INIT/INIT-ACK
 * Note: currently only used for INIT as INIT-ACK is handled inline
 * with sctp_load_addresses_from_init()
 */
int
sctp_validate_init_auth_params(struct mbuf *m, int offset, int limit)
{
        struct sctp_paramhdr *phdr, param_buf;
        uint16_t ptype, plen;
        int peer_supports_asconf = 0;
        int peer_supports_auth = 0;
        int got_random = 0, got_hmacs = 0, got_chklist = 0;
        uint8_t saw_asconf = 0;
        uint8_t saw_asconf_ack = 0;
 
        /* go through each of the params. */
        phdr = sctp_get_next_param(m, offset, &param_buf, sizeof(param_buf));
        while (phdr) {
                ptype = ntohs(phdr->param_type);
                plen = ntohs(phdr->param_length);
 
                if (offset + plen > limit) {
                        break;
                }
                if (plen < sizeof(struct sctp_paramhdr)) {
                        break;
                }
                if (ptype == SCTP_SUPPORTED_CHUNK_EXT) {
                        /* A supported extension chunk */
                        struct sctp_supported_chunk_types_param *pr_supported;
                        uint8_t local_store[SCTP_SMALL_CHUNK_STORE];
                        int num_ent, i;
 
                        if (plen > sizeof(local_store)) {
                                break;
                        }
                        phdr = sctp_get_next_param(m, offset,
                            (struct sctp_paramhdr *)&local_store,
                            plen);
                        if (phdr == NULL) {
                                return (-1);
                        }
                        pr_supported = (struct sctp_supported_chunk_types_param *)phdr;
                        num_ent = plen - sizeof(struct sctp_paramhdr);
                        for (i = 0; i < num_ent; i++) {
                                switch (pr_supported->chunk_types[i]) {
                                case SCTP_ASCONF:
                                case SCTP_ASCONF_ACK:
                                        peer_supports_asconf = 1;
                                        break;
                                default:
                                        /* one we don't care about */
                                        break;
                                }
                        }
                } else if (ptype == SCTP_RANDOM) {
                        /* enforce the random length */
                        if (plen != (sizeof(struct sctp_auth_random) +
                            SCTP_AUTH_RANDOM_SIZE_REQUIRED)) {
                                SCTPDBG(SCTP_DEBUG_AUTH1,
                                    "SCTP: invalid RANDOM len\n");
                                return (-1);
                        }
                        got_random = 1;
                } else if (ptype == SCTP_HMAC_LIST) {
                        struct sctp_auth_hmac_algo *hmacs;
                        uint8_t store[SCTP_PARAM_BUFFER_SIZE];
                        int num_hmacs;
 
                        if (plen > sizeof(store)) {
                                break;
                        }
                        phdr = sctp_get_next_param(m, offset,
                            (struct sctp_paramhdr *)store,
                            plen);
                        if (phdr == NULL) {
                                return (-1);
                        }
                        hmacs = (struct sctp_auth_hmac_algo *)phdr;
                        num_hmacs = (plen - sizeof(*hmacs)) / sizeof(hmacs->hmac_ids[0]);
                        /* validate the hmac list */
                        if (sctp_verify_hmac_param(hmacs, num_hmacs)) {
                                SCTPDBG(SCTP_DEBUG_AUTH1,
                                    "SCTP: invalid HMAC param\n");
                                return (-1);
                        }
                        got_hmacs = 1;
                } else if (ptype == SCTP_CHUNK_LIST) {
                        struct sctp_auth_chunk_list *chunks;
                        uint8_t chunks_store[SCTP_SMALL_CHUNK_STORE];
                        int i, num_chunks;
 
                        if (plen > sizeof(chunks_store)) {
                                break;
                        }
                        phdr = sctp_get_next_param(m, offset,
                            (struct sctp_paramhdr *)chunks_store,
                            plen);
                        if (phdr == NULL) {
                                return (-1);
                        }
                        /*-
                         * Flip through the list and mark that the
                         * peer supports asconf/asconf_ack.
                         */
                        chunks = (struct sctp_auth_chunk_list *)phdr;
                        num_chunks = plen - sizeof(*chunks);
                        for (i = 0; i < num_chunks; i++) {
                                /* record asconf/asconf-ack if listed */
                                if (chunks->chunk_types[i] == SCTP_ASCONF)
                                        saw_asconf = 1;
                                if (chunks->chunk_types[i] == SCTP_ASCONF_ACK)
                                        saw_asconf_ack = 1;
                        }
                        if (num_chunks)
                                got_chklist = 1;
                }
 
                offset += SCTP_SIZE32(plen);
                if (offset >= limit) {
                        break;
                }
                phdr = sctp_get_next_param(m, offset, &param_buf,
                    sizeof(param_buf));
        }
        /* validate authentication required parameters */
        if (got_random && got_hmacs) {
                peer_supports_auth = 1;
        } else {
                peer_supports_auth = 0;
        }
        if (!peer_supports_auth && got_chklist) {
                SCTPDBG(SCTP_DEBUG_AUTH1,
                    "SCTP: peer sent chunk list w/o AUTH\n");
                return (-1);
        }
        if (peer_supports_asconf && !peer_supports_auth) {
                SCTPDBG(SCTP_DEBUG_AUTH1,
                    "SCTP: peer supports ASCONF but not AUTH\n");
                return (-1);
        } else if ((peer_supports_asconf) && (peer_supports_auth) &&
            ((saw_asconf == 0) || (saw_asconf_ack == 0))) {
                return (-2);
        }
        return (0);
}
 
void
sctp_initialize_auth_params(struct sctp_inpcb *inp, struct sctp_tcb *stcb)
{
        uint16_t chunks_len = 0;
        uint16_t hmacs_len = 0;
        uint16_t random_len = SCTP_AUTH_RANDOM_SIZE_DEFAULT;
        sctp_key_t *new_key;
        uint16_t keylen;
 
        /* initialize hmac list from endpoint */
        stcb->asoc.local_hmacs = sctp_copy_hmaclist(inp->sctp_ep.local_hmacs);
        if (stcb->asoc.local_hmacs != NULL) {
                hmacs_len = stcb->asoc.local_hmacs->num_algo *
                    sizeof(stcb->asoc.local_hmacs->hmac[0]);
        }
        /* initialize auth chunks list from endpoint */
        stcb->asoc.local_auth_chunks =
            sctp_copy_chunklist(inp->sctp_ep.local_auth_chunks);
        if (stcb->asoc.local_auth_chunks != NULL) {
                int i;
 
                for (i = 0; i < 256; i++) {
                        if (stcb->asoc.local_auth_chunks->chunks[i])
                                chunks_len++;
                }
        }
        /* copy defaults from the endpoint */
        stcb->asoc.authinfo.active_keyid = inp->sctp_ep.default_keyid;
 
        /* copy out the shared key list (by reference) from the endpoint */
        (void)sctp_copy_skeylist(&inp->sctp_ep.shared_keys,
            &stcb->asoc.shared_keys);
 
        /* now set the concatenated key (random + chunks + hmacs) */
        /* key includes parameter headers */
        keylen = (3 * sizeof(struct sctp_paramhdr)) + random_len + chunks_len +
            hmacs_len;
        new_key = sctp_alloc_key(keylen);
        if (new_key != NULL) {
                struct sctp_paramhdr *ph;
                int plen;
 
                /* generate and copy in the RANDOM */
                ph = (struct sctp_paramhdr *)new_key->key;
                ph->param_type = htons(SCTP_RANDOM);
                plen = sizeof(*ph) + random_len;
                ph->param_length = htons(plen);
                SCTP_READ_RANDOM(new_key->key + sizeof(*ph), random_len);
                keylen = plen;
 
                /* append in the AUTH chunks */
                /* NOTE: currently we always have chunks to list */
                ph = (struct sctp_paramhdr *)(new_key->key + keylen);
                ph->param_type = htons(SCTP_CHUNK_LIST);
                plen = sizeof(*ph) + chunks_len;
                ph->param_length = htons(plen);
                keylen += sizeof(*ph);
                if (stcb->asoc.local_auth_chunks) {
                        int i;
 
                        for (i = 0; i < 256; i++) {
                                if (stcb->asoc.local_auth_chunks->chunks[i])
                                        new_key->key[keylen++] = i;
                        }
                }
 
                /* append in the HMACs */
                ph = (struct sctp_paramhdr *)(new_key->key + keylen);
                ph->param_type = htons(SCTP_HMAC_LIST);
                plen = sizeof(*ph) + hmacs_len;
                ph->param_length = htons(plen);
                keylen += sizeof(*ph);
                (void)sctp_serialize_hmaclist(stcb->asoc.local_hmacs,
                    new_key->key + keylen);
        }
        if (stcb->asoc.authinfo.random != NULL)
                sctp_free_key(stcb->asoc.authinfo.random);
        stcb->asoc.authinfo.random = new_key;
        stcb->asoc.authinfo.random_len = random_len;
}