/* * hmac_ossl.c * * Implementation of hmac auth_type_t that leverages OpenSSL * * John A. Foley * Cisco Systems, Inc. */ /* * * Copyright(c) 2013, 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. * */ #include "hmac.h" #include "alloc.h" #include /* the debug module for authentiation */ debug_module_t mod_hmac = { 0, /* debugging is off by default */ "hmac sha-1 openssl" /* 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; hmac_ctx_t *new_hmac_ctx; 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; new_hmac_ctx = (hmac_ctx_t*)((*a)->state); memset(new_hmac_ctx, 0, sizeof(hmac_ctx_t)); /* increment global count of all hmac uses */ hmac.ref_count++; return err_status_ok; } err_status_t hmac_dealloc (auth_t *a) { extern auth_type_t hmac; hmac_ctx_t *hmac_ctx; hmac_ctx = (hmac_ctx_t*)a->state; if (hmac_ctx->ctx_initialized) { EVP_MD_CTX_cleanup(&hmac_ctx->ctx); } if (hmac_ctx->init_ctx_initialized) { EVP_MD_CTX_cleanup(&hmac_ctx->init_ctx); } /* zeroize entire state*/ octet_string_set_to_zero((uint8_t*)a, sizeof(hmac_ctx_t) + sizeof(auth_t)); /* free memory */ crypto_free(a); /* decrement global count of all hmac uses */ hmac.ref_count--; 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 */ sha1_init(&state->init_ctx); state->init_ctx_initialized = 1; /* hash ipad ^ key */ sha1_update(&state->init_ctx, ipad, 64); return (hmac_start(state)); } err_status_t hmac_start (hmac_ctx_t *state) { if (state->ctx_initialized) { EVP_MD_CTX_cleanup(&state->ctx); } if (!EVP_MD_CTX_copy(&state->ctx, &state->init_ctx)) { return err_status_auth_fail; } else { state->ctx_initialized = 1; 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 */ 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 */ sha1_update(&state->ctx, message, msg_octets); 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 */ sha1_init(&state->ctx); /* hash opad ^ key */ sha1_update(&state->ctx, (uint8_t*)state->opad, 64); /* hash the result of the inner hash */ sha1_update(&state->ctx, (uint8_t*)H, 20); /* the result is returned in the array hash_value[] */ 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, (int) 0, /* instance count */ (auth_test_case_t*) &hmac_test_case_0, (debug_module_t*) &mod_hmac, (auth_type_id_t) HMAC_SHA1 };