| /* |
| * hmac.c |
| * |
| * implementation of hmac auth_type_t |
| * |
| * David A. McGrew |
| * Cisco Systems, Inc. |
| */ |
| /* |
| * |
| * Copyright(c) 2001-2006 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" |
| |
| /* the debug module for authentiation */ |
| |
| debug_module_t mod_hmac = { |
| 0, /* debugging is off by default */ |
| "hmac sha-1" /* printable name for module */ |
| }; |
| |
| |
| err_status_t |
| hmac_alloc(auth_t **a, int key_len, int out_len) { |
| extern auth_type_t hmac; |
| uint8_t *pointer; |
| |
| debug_print(mod_hmac, "allocating auth func with key length %d", key_len); |
| debug_print(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 err_status_bad_param; |
| |
| /* check output length - should be less than 20 bytes */ |
| if (out_len > 20) |
| return err_status_bad_param; |
| |
| /* allocate memory for auth and hmac_ctx_t structures */ |
| pointer = (uint8_t*)crypto_alloc(sizeof(hmac_ctx_t) + sizeof(auth_t)); |
| if (pointer == NULL) |
| return err_status_alloc_fail; |
| |
| /* set pointers */ |
| *a = (auth_t *)pointer; |
| (*a)->type = &hmac; |
| (*a)->state = pointer + sizeof(auth_t); |
| (*a)->out_len = out_len; |
| (*a)->key_len = key_len; |
| (*a)->prefix_len = 0; |
| |
| return err_status_ok; |
| } |
| |
| err_status_t |
| hmac_dealloc(auth_t *a) { |
| extern auth_type_t hmac; |
| |
| /* zeroize entire state*/ |
| octet_string_set_to_zero((uint8_t *)a, |
| sizeof(hmac_ctx_t) + sizeof(auth_t)); |
| |
| /* free memory */ |
| crypto_free(a); |
| |
| return err_status_ok; |
| } |
| |
| err_status_t |
| hmac_init(hmac_ctx_t *state, const uint8_t *key, int key_len) { |
| 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 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(mod_hmac, "ipad: %s", 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 err_status_ok; |
| } |
| |
| err_status_t |
| hmac_start(hmac_ctx_t *state) { |
| |
| memcpy(&state->ctx, &state->init_ctx, sizeof(srtp_sha1_ctx_t)); |
| |
| return err_status_ok; |
| } |
| |
| err_status_t |
| hmac_update(hmac_ctx_t *state, const uint8_t *message, int msg_octets) { |
| |
| debug_print(mod_hmac, "input: %s", |
| octet_string_hex_string(message, msg_octets)); |
| |
| /* hash message into sha1 context */ |
| srtp_sha1_update(&state->ctx, message, msg_octets); |
| |
| return err_status_ok; |
| } |
| |
| err_status_t |
| hmac_compute(hmac_ctx_t *state, const void *message, |
| int msg_octets, int tag_len, uint8_t *result) { |
| 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 err_status_bad_param; |
| |
| /* hash message, copy output into H */ |
| hmac_update(state, (const uint8_t*)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(mod_hmac, "intermediate state: %s", |
| 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(mod_hmac, "output: %s", |
| octet_string_hex_string((uint8_t *)hash_value, tag_len)); |
| |
| return err_status_ok; |
| } |
| |
| |
| /* begin test case 0 */ |
| |
| uint8_t |
| hmac_test_case_0_key[20] = { |
| 0x0b, 0x0b, 0x0b, 0x0b, 0x0b, 0x0b, 0x0b, 0x0b, |
| 0x0b, 0x0b, 0x0b, 0x0b, 0x0b, 0x0b, 0x0b, 0x0b, |
| 0x0b, 0x0b, 0x0b, 0x0b |
| }; |
| |
| uint8_t |
| hmac_test_case_0_data[8] = { |
| 0x48, 0x69, 0x20, 0x54, 0x68, 0x65, 0x72, 0x65 /* "Hi There" */ |
| }; |
| |
| uint8_t |
| hmac_test_case_0_tag[20] = { |
| 0xb6, 0x17, 0x31, 0x86, 0x55, 0x05, 0x72, 0x64, |
| 0xe2, 0x8b, 0xc0, 0xb6, 0xfb, 0x37, 0x8c, 0x8e, |
| 0xf1, 0x46, 0xbe, 0x00 |
| }; |
| |
| auth_test_case_t |
| hmac_test_case_0 = { |
| 20, /* octets in key */ |
| hmac_test_case_0_key, /* key */ |
| 8, /* octets in data */ |
| hmac_test_case_0_data, /* data */ |
| 20, /* octets in tag */ |
| hmac_test_case_0_tag, /* tag */ |
| NULL /* pointer to next testcase */ |
| }; |
| |
| /* end test case 0 */ |
| |
| char hmac_description[] = "hmac sha-1 authentication function"; |
| |
| /* |
| * auth_type_t hmac is the hmac metaobject |
| */ |
| |
| auth_type_t |
| hmac = { |
| (auth_alloc_func) hmac_alloc, |
| (auth_dealloc_func) hmac_dealloc, |
| (auth_init_func) hmac_init, |
| (auth_compute_func) hmac_compute, |
| (auth_update_func) hmac_update, |
| (auth_start_func) hmac_start, |
| (char *) hmac_description, |
| (auth_test_case_t *) &hmac_test_case_0, |
| (debug_module_t *) &mod_hmac, |
| (auth_type_id_t) HMAC_SHA1 |
| }; |
| |