/* * hmac_ossl.c * * Implementation of hmac srtp_auth_type_t that leverages OpenSSL * * John A. Foley * Cisco Systems, Inc. */ /* * * Copyright(c) 2013-2017, 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 #endif #include "auth.h" #include "alloc.h" #include "err.h" /* for srtp_debug */ #include #include #define SHA1_DIGEST_SIZE 20 /* the debug module for authentiation */ srtp_debug_module_t srtp_mod_hmac = { 0, /* debugging is off by default */ "hmac sha-1 openssl" /* 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; 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 output length - should be less than 20 bytes */ if (out_len > SHA1_DIGEST_SIZE) { return srtp_err_status_bad_param; } /* OpenSSL 1.1.0 made HMAC_CTX an opaque structure, which must be allocated using HMAC_CTX_new. But this function doesn't exist in OpenSSL 1.0.x. */ #if OPENSSL_VERSION_NUMBER < 0x10100000L { /* allocate memory for auth and HMAC_CTX structures */ uint8_t* pointer; HMAC_CTX *new_hmac_ctx; pointer = (uint8_t*)srtp_crypto_alloc(sizeof(HMAC_CTX) + sizeof(srtp_auth_t)); if (pointer == NULL) { return srtp_err_status_alloc_fail; } *a = (srtp_auth_t*)pointer; (*a)->state = pointer + sizeof(srtp_auth_t); new_hmac_ctx = (HMAC_CTX*)((*a)->state); HMAC_CTX_init(new_hmac_ctx); } #else *a = (srtp_auth_t*)srtp_crypto_alloc(sizeof(srtp_auth_t)); if (*a == NULL) { return srtp_err_status_alloc_fail; } (*a)->state = HMAC_CTX_new(); if ((*a)->state == NULL) { srtp_crypto_free(*a); *a = NULL; return srtp_err_status_alloc_fail; } #endif /* set pointers */ (*a)->type = &srtp_hmac; (*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) { HMAC_CTX *hmac_ctx; hmac_ctx = (HMAC_CTX*)a->state; #if OPENSSL_VERSION_NUMBER < 0x10100000L HMAC_CTX_cleanup(hmac_ctx); /* zeroize entire state*/ octet_string_set_to_zero(a, sizeof(HMAC_CTX) + sizeof(srtp_auth_t)); #else HMAC_CTX_free(hmac_ctx); /* zeroize entire state*/ octet_string_set_to_zero(a, sizeof(srtp_auth_t)); #endif /* free memory */ srtp_crypto_free(a); return srtp_err_status_ok; } static srtp_err_status_t srtp_hmac_start (void *statev) { HMAC_CTX *state = (HMAC_CTX *)statev; if (HMAC_Init_ex(state, NULL, 0, NULL, NULL) == 0) return srtp_err_status_auth_fail; return srtp_err_status_ok; } static srtp_err_status_t srtp_hmac_init (void *statev, const uint8_t *key, int key_len) { HMAC_CTX *state = (HMAC_CTX *)statev; if (HMAC_Init_ex(state, key, key_len, EVP_sha1(), NULL) == 0) return srtp_err_status_auth_fail; return srtp_err_status_ok; } static srtp_err_status_t srtp_hmac_update (void *statev, const uint8_t *message, int msg_octets) { HMAC_CTX *state = (HMAC_CTX *)statev; debug_print(srtp_mod_hmac, "input: %s", srtp_octet_string_hex_string(message, msg_octets)); if (HMAC_Update(state, message, msg_octets) == 0) return srtp_err_status_auth_fail; 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) { HMAC_CTX *state = (HMAC_CTX *)statev; uint8_t hash_value[SHA1_DIGEST_SIZE]; int i; unsigned int len; /* check tag length, return error if we can't provide the value expected */ if (tag_len > SHA1_DIGEST_SIZE) { return srtp_err_status_bad_param; } /* hash message, copy output into H */ if (HMAC_Update(state, message, msg_octets) == 0) return srtp_err_status_auth_fail; if (HMAC_Final(state, hash_value, &len) == 0) return srtp_err_status_auth_fail; if (len < tag_len) return srtp_err_status_auth_fail; /* copy hash_value to *result */ for (i = 0; i < tag_len; i++) { result[i] = hash_value[i]; } debug_print(srtp_mod_hmac, "output: %s", srtp_octet_string_hex_string(hash_value, tag_len)); return srtp_err_status_ok; } /* begin test case 0 */ static const uint8_t srtp_hmac_test_case_0_key[SHA1_DIGEST_SIZE] = { 0x0b, 0x0b, 0x0b, 0x0b, 0x0b, 0x0b, 0x0b, 0x0b, 0x0b, 0x0b, 0x0b, 0x0b, 0x0b, 0x0b, 0x0b, 0x0b, 0x0b, 0x0b, 0x0b, 0x0b }; static const uint8_t srtp_hmac_test_case_0_data[8] = { 0x48, 0x69, 0x20, 0x54, 0x68, 0x65, 0x72, 0x65 /* "Hi There" */ }; static const uint8_t srtp_hmac_test_case_0_tag[SHA1_DIGEST_SIZE] = { 0xb6, 0x17, 0x31, 0x86, 0x55, 0x05, 0x72, 0x64, 0xe2, 0x8b, 0xc0, 0xb6, 0xfb, 0x37, 0x8c, 0x8e, 0xf1, 0x46, 0xbe, 0x00 }; static const srtp_auth_test_case_t srtp_hmac_test_case_0 = { sizeof(srtp_hmac_test_case_0_key), /* octets in key */ srtp_hmac_test_case_0_key, /* key */ sizeof(srtp_hmac_test_case_0_data), /* octets in data */ srtp_hmac_test_case_0_data, /* data */ sizeof(srtp_hmac_test_case_0_tag), /* octets in tag */ srtp_hmac_test_case_0_tag, /* tag */ NULL /* pointer to next testcase */ }; /* end test case 0 */ 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 };