diff options
Diffstat (limited to 'third_party/libsrtp/src/crypto/hash/hmac.c')
| -rw-r--r-- | third_party/libsrtp/src/crypto/hash/hmac.c | 249 |
1 files changed, 249 insertions, 0 deletions
diff --git a/third_party/libsrtp/src/crypto/hash/hmac.c b/third_party/libsrtp/src/crypto/hash/hmac.c new file mode 100644 index 0000000000..269c3f6a71 --- /dev/null +++ b/third_party/libsrtp/src/crypto/hash/hmac.c @@ -0,0 +1,249 @@ +/* + * hmac.c + * + * implementation of hmac srtp_auth_type_t + * + * David A. McGrew + * Cisco Systems, Inc. + */ +/* + * + * Copyright(c) 2001-2017 Cisco Systems, Inc. + * All rights reserved. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions + * are met: + * + * Redistributions of source code must retain the above copyright + * notice, this list of conditions and the following disclaimer. + * + * 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. + * + * Neither the name of the 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 HOLDERS 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. + * + */ + +#ifdef HAVE_CONFIG_H +#include <config.h> +#endif + +#include "hmac.h" +#include "alloc.h" +#include "cipher_types.h" +#include "auth_test_cases.h" + +/* the debug module for authentiation */ + +srtp_debug_module_t srtp_mod_hmac = { + 0, /* debugging is off by default */ + "hmac sha-1" /* printable name for module */ +}; + +static srtp_err_status_t srtp_hmac_alloc(srtp_auth_t **a, + int key_len, + int out_len) +{ + extern const srtp_auth_type_t srtp_hmac; + uint8_t *pointer; + + debug_print(srtp_mod_hmac, "allocating auth func with key length %d", + key_len); + debug_print(srtp_mod_hmac, " tag length %d", + out_len); + + /* + * check key length - note that we don't support keys larger + * than 20 bytes yet + */ + if (key_len > 20) { + return srtp_err_status_bad_param; + } + + /* check output length - should be less than 20 bytes */ + if (out_len > 20) { + return srtp_err_status_bad_param; + } + + /* allocate memory for auth and srtp_hmac_ctx_t structures */ + pointer = (uint8_t *)srtp_crypto_alloc(sizeof(srtp_hmac_ctx_t) + + sizeof(srtp_auth_t)); + if (pointer == NULL) { + return srtp_err_status_alloc_fail; + } + + /* set pointers */ + *a = (srtp_auth_t *)pointer; + (*a)->type = &srtp_hmac; + (*a)->state = pointer + sizeof(srtp_auth_t); + (*a)->out_len = out_len; + (*a)->key_len = key_len; + (*a)->prefix_len = 0; + + return srtp_err_status_ok; +} + +static srtp_err_status_t srtp_hmac_dealloc(srtp_auth_t *a) +{ + /* zeroize entire state*/ + octet_string_set_to_zero(a, sizeof(srtp_hmac_ctx_t) + sizeof(srtp_auth_t)); + + /* free memory */ + srtp_crypto_free(a); + + return srtp_err_status_ok; +} + +static srtp_err_status_t srtp_hmac_init(void *statev, + const uint8_t *key, + int key_len) +{ + srtp_hmac_ctx_t *state = (srtp_hmac_ctx_t *)statev; + int i; + uint8_t ipad[64]; + + /* + * check key length - note that we don't support keys larger + * than 20 bytes yet + */ + if (key_len > 20) { + return srtp_err_status_bad_param; + } + + /* + * set values of ipad and opad by exoring the key into the + * appropriate constant values + */ + for (i = 0; i < key_len; i++) { + ipad[i] = key[i] ^ 0x36; + state->opad[i] = key[i] ^ 0x5c; + } + /* set the rest of ipad, opad to constant values */ + for (; i < 64; i++) { + ipad[i] = 0x36; + ((uint8_t *)state->opad)[i] = 0x5c; + } + + debug_print(srtp_mod_hmac, "ipad: %s", + srtp_octet_string_hex_string(ipad, 64)); + + /* initialize sha1 context */ + srtp_sha1_init(&state->init_ctx); + + /* hash ipad ^ key */ + srtp_sha1_update(&state->init_ctx, ipad, 64); + memcpy(&state->ctx, &state->init_ctx, sizeof(srtp_sha1_ctx_t)); + + return srtp_err_status_ok; +} + +static srtp_err_status_t srtp_hmac_start(void *statev) +{ + srtp_hmac_ctx_t *state = (srtp_hmac_ctx_t *)statev; + + memcpy(&state->ctx, &state->init_ctx, sizeof(srtp_sha1_ctx_t)); + + return srtp_err_status_ok; +} + +static srtp_err_status_t srtp_hmac_update(void *statev, + const uint8_t *message, + int msg_octets) +{ + srtp_hmac_ctx_t *state = (srtp_hmac_ctx_t *)statev; + + debug_print(srtp_mod_hmac, "input: %s", + srtp_octet_string_hex_string(message, msg_octets)); + + /* hash message into sha1 context */ + srtp_sha1_update(&state->ctx, message, msg_octets); + + return srtp_err_status_ok; +} + +static srtp_err_status_t srtp_hmac_compute(void *statev, + const uint8_t *message, + int msg_octets, + int tag_len, + uint8_t *result) +{ + srtp_hmac_ctx_t *state = (srtp_hmac_ctx_t *)statev; + uint32_t hash_value[5]; + uint32_t H[5]; + int i; + + /* check tag length, return error if we can't provide the value expected */ + if (tag_len > 20) { + return srtp_err_status_bad_param; + } + + /* hash message, copy output into H */ + srtp_hmac_update(state, message, msg_octets); + srtp_sha1_final(&state->ctx, H); + + /* + * note that we don't need to debug_print() the input, since the + * function hmac_update() already did that for us + */ + debug_print(srtp_mod_hmac, "intermediate state: %s", + srtp_octet_string_hex_string((uint8_t *)H, 20)); + + /* re-initialize hash context */ + srtp_sha1_init(&state->ctx); + + /* hash opad ^ key */ + srtp_sha1_update(&state->ctx, (uint8_t *)state->opad, 64); + + /* hash the result of the inner hash */ + srtp_sha1_update(&state->ctx, (uint8_t *)H, 20); + + /* the result is returned in the array hash_value[] */ + srtp_sha1_final(&state->ctx, hash_value); + + /* copy hash_value to *result */ + for (i = 0; i < tag_len; i++) { + result[i] = ((uint8_t *)hash_value)[i]; + } + + debug_print(srtp_mod_hmac, "output: %s", + srtp_octet_string_hex_string((uint8_t *)hash_value, tag_len)); + + return srtp_err_status_ok; +} + +static const char srtp_hmac_description[] = + "hmac sha-1 authentication function"; + +/* + * srtp_auth_type_t hmac is the hmac metaobject + */ + +const srtp_auth_type_t srtp_hmac = { + srtp_hmac_alloc, /* */ + srtp_hmac_dealloc, /* */ + srtp_hmac_init, /* */ + srtp_hmac_compute, /* */ + srtp_hmac_update, /* */ + srtp_hmac_start, /* */ + srtp_hmac_description, /* */ + &srtp_hmac_test_case_0, /* */ + SRTP_HMAC_SHA1 /* */ +}; |