1 /* $NetBSD: hmac.c,v 1.1.1.1 2011/04/13 18:14:50 elric Exp $ */ 2 3 /* 4 * Copyright (c) 2006 - 2007 Kungliga Tekniska Högskolan 5 * (Royal Institute of Technology, Stockholm, Sweden). 6 * All rights reserved. 7 * 8 * Redistribution and use in source and binary forms, with or without 9 * modification, are permitted provided that the following conditions 10 * are met: 11 * 12 * 1. Redistributions of source code must retain the above copyright 13 * notice, this list of conditions and the following disclaimer. 14 * 15 * 2. Redistributions in binary form must reproduce the above copyright 16 * notice, this list of conditions and the following disclaimer in the 17 * documentation and/or other materials provided with the distribution. 18 * 19 * 3. Neither the name of the Institute nor the names of its contributors 20 * may be used to endorse or promote products derived from this software 21 * without specific prior written permission. 22 * 23 * THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND 24 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 25 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 26 * ARE DISCLAIMED. IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE 27 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 28 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 29 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 30 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 31 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 32 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 33 * SUCH DAMAGE. 34 */ 35 36 #include <sys/types.h> 37 #include <stdio.h> 38 #include <stdlib.h> 39 #include <string.h> 40 #include <hmac.h> 41 42 void 43 HMAC_CTX_init(HMAC_CTX *ctx) 44 { 45 memset(ctx, 0, sizeof(*ctx)); 46 } 47 48 void 49 HMAC_CTX_cleanup(HMAC_CTX *ctx) 50 { 51 if (ctx->buf) { 52 memset(ctx->buf, 0, ctx->key_length); 53 free(ctx->buf); 54 ctx->buf = NULL; 55 } 56 if (ctx->opad) { 57 memset(ctx->opad, 0, EVP_MD_block_size(ctx->md)); 58 free(ctx->opad); 59 ctx->opad = NULL; 60 } 61 if (ctx->ipad) { 62 memset(ctx->ipad, 0, EVP_MD_block_size(ctx->md)); 63 free(ctx->ipad); 64 ctx->ipad = NULL; 65 } 66 if (ctx->ctx) { 67 EVP_MD_CTX_destroy(ctx->ctx); 68 ctx->ctx = NULL; 69 } 70 } 71 72 size_t 73 HMAC_size(const HMAC_CTX *ctx) 74 { 75 return EVP_MD_size(ctx->md); 76 } 77 78 void 79 HMAC_Init_ex(HMAC_CTX *ctx, 80 const void *key, 81 size_t keylen, 82 const EVP_MD *md, 83 ENGINE *engine) 84 { 85 unsigned char *p; 86 size_t i; 87 88 if (ctx->md != md) { 89 ctx->md = md; 90 if (ctx->buf) { 91 memset(ctx->buf, 0, ctx->key_length); 92 free (ctx->buf); 93 } 94 ctx->key_length = EVP_MD_size(ctx->md); 95 ctx->buf = malloc(ctx->key_length); 96 } 97 #if 0 98 ctx->engine = engine; 99 #endif 100 101 if (keylen > EVP_MD_block_size(ctx->md)) { 102 EVP_Digest(key, keylen, ctx->buf, NULL, ctx->md, engine); 103 key = ctx->buf; 104 keylen = EVP_MD_size(ctx->md); 105 } 106 107 if (ctx->opad) { 108 memset(ctx->opad, 0, ctx->key_length); 109 free(ctx->opad); 110 } 111 if (ctx->ipad) { 112 memset(ctx->ipad, 0, ctx->key_length); 113 free(ctx->ipad); 114 } 115 116 ctx->opad = malloc(EVP_MD_block_size(ctx->md)); 117 ctx->ipad = malloc(EVP_MD_block_size(ctx->md)); 118 memset(ctx->ipad, 0x36, EVP_MD_block_size(ctx->md)); 119 memset(ctx->opad, 0x5c, EVP_MD_block_size(ctx->md)); 120 121 for (i = 0, p = ctx->ipad; i < keylen; i++) 122 p[i] ^= ((const unsigned char *)key)[i]; 123 for (i = 0, p = ctx->opad; i < keylen; i++) 124 p[i] ^= ((const unsigned char *)key)[i]; 125 126 if (ctx->ctx == NULL) 127 ctx->ctx = EVP_MD_CTX_create(); 128 129 EVP_DigestInit_ex(ctx->ctx, ctx->md, ctx->engine); 130 EVP_DigestUpdate(ctx->ctx, ctx->ipad, EVP_MD_block_size(ctx->md)); 131 } 132 133 void 134 HMAC_Update(HMAC_CTX *ctx, const void *data, size_t len) 135 { 136 EVP_DigestUpdate(ctx->ctx, data, len); 137 } 138 139 void 140 HMAC_Final(HMAC_CTX *ctx, void *md, unsigned int *len) 141 { 142 EVP_DigestFinal_ex(ctx->ctx, ctx->buf, NULL); 143 144 EVP_DigestInit_ex(ctx->ctx, ctx->md, ctx->engine); 145 EVP_DigestUpdate(ctx->ctx, ctx->opad, EVP_MD_block_size(ctx->md)); 146 EVP_DigestUpdate(ctx->ctx, ctx->buf, ctx->key_length); 147 EVP_DigestFinal_ex(ctx->ctx, md, len); 148 } 149 150 void * 151 HMAC(const EVP_MD *md, 152 const void *key, size_t key_size, 153 const void *data, size_t data_size, 154 void *hash, unsigned int *hash_len) 155 { 156 HMAC_CTX ctx; 157 158 HMAC_CTX_init(&ctx); 159 HMAC_Init_ex(&ctx, key, key_size, md, NULL); 160 HMAC_Update(&ctx, data, data_size); 161 HMAC_Final(&ctx, hash, hash_len); 162 HMAC_CTX_cleanup(&ctx); 163 return hash; 164 } 165