1 /* $NetBSD: hmac.c,v 1.2 2017/01/28 21:31:47 christos 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 <config.h> 37 #include <krb5/roken.h> 38 39 #include <hmac.h> 40 41 void 42 HMAC_CTX_init(HMAC_CTX *ctx) 43 { 44 memset(ctx, 0, sizeof(*ctx)); 45 } 46 47 void 48 HMAC_CTX_cleanup(HMAC_CTX *ctx) 49 { 50 if (ctx->buf) { 51 memset(ctx->buf, 0, ctx->key_length); 52 free(ctx->buf); 53 ctx->buf = NULL; 54 } 55 if (ctx->opad) { 56 memset(ctx->opad, 0, EVP_MD_block_size(ctx->md)); 57 free(ctx->opad); 58 ctx->opad = NULL; 59 } 60 if (ctx->ipad) { 61 memset(ctx->ipad, 0, EVP_MD_block_size(ctx->md)); 62 free(ctx->ipad); 63 ctx->ipad = NULL; 64 } 65 if (ctx->ctx) { 66 EVP_MD_CTX_destroy(ctx->ctx); 67 ctx->ctx = NULL; 68 } 69 } 70 71 size_t 72 HMAC_size(const HMAC_CTX *ctx) 73 { 74 return EVP_MD_size(ctx->md); 75 } 76 77 void 78 HMAC_Init_ex(HMAC_CTX *ctx, 79 const void *key, 80 size_t keylen, 81 const EVP_MD *md, 82 ENGINE *engine) 83 { 84 unsigned char *p; 85 size_t i; 86 87 if (ctx->md != md) { 88 ctx->md = md; 89 if (ctx->buf) { 90 memset(ctx->buf, 0, ctx->key_length); 91 free (ctx->buf); 92 } 93 ctx->key_length = EVP_MD_size(ctx->md); 94 ctx->buf = malloc(ctx->key_length); 95 } 96 #if 0 97 ctx->engine = engine; 98 #endif 99 100 if (keylen > EVP_MD_block_size(ctx->md)) { 101 EVP_Digest(key, keylen, ctx->buf, NULL, ctx->md, engine); 102 key = ctx->buf; 103 keylen = EVP_MD_size(ctx->md); 104 } 105 106 if (ctx->opad) { 107 memset(ctx->opad, 0, ctx->key_length); 108 free(ctx->opad); 109 } 110 if (ctx->ipad) { 111 memset(ctx->ipad, 0, ctx->key_length); 112 free(ctx->ipad); 113 } 114 115 ctx->opad = malloc(EVP_MD_block_size(ctx->md)); 116 ctx->ipad = malloc(EVP_MD_block_size(ctx->md)); 117 memset(ctx->ipad, 0x36, EVP_MD_block_size(ctx->md)); 118 memset(ctx->opad, 0x5c, EVP_MD_block_size(ctx->md)); 119 120 for (i = 0, p = ctx->ipad; i < keylen; i++) 121 p[i] ^= ((const unsigned char *)key)[i]; 122 for (i = 0, p = ctx->opad; i < keylen; i++) 123 p[i] ^= ((const unsigned char *)key)[i]; 124 125 if (ctx->ctx == NULL) 126 ctx->ctx = EVP_MD_CTX_create(); 127 128 EVP_DigestInit_ex(ctx->ctx, ctx->md, ctx->engine); 129 EVP_DigestUpdate(ctx->ctx, ctx->ipad, EVP_MD_block_size(ctx->md)); 130 } 131 132 void 133 HMAC_Update(HMAC_CTX *ctx, const void *data, size_t len) 134 { 135 EVP_DigestUpdate(ctx->ctx, data, len); 136 } 137 138 void 139 HMAC_Final(HMAC_CTX *ctx, void *md, unsigned int *len) 140 { 141 EVP_DigestFinal_ex(ctx->ctx, ctx->buf, NULL); 142 143 EVP_DigestInit_ex(ctx->ctx, ctx->md, ctx->engine); 144 EVP_DigestUpdate(ctx->ctx, ctx->opad, EVP_MD_block_size(ctx->md)); 145 EVP_DigestUpdate(ctx->ctx, ctx->buf, ctx->key_length); 146 EVP_DigestFinal_ex(ctx->ctx, md, len); 147 } 148 149 void * 150 HMAC(const EVP_MD *md, 151 const void *key, size_t key_size, 152 const void *data, size_t data_size, 153 void *hash, unsigned int *hash_len) 154 { 155 HMAC_CTX ctx; 156 157 HMAC_CTX_init(&ctx); 158 HMAC_Init_ex(&ctx, key, key_size, md, NULL); 159 HMAC_Update(&ctx, data, data_size); 160 HMAC_Final(&ctx, hash, hash_len); 161 HMAC_CTX_cleanup(&ctx); 162 return hash; 163 } 164