1 /* $OpenBSD: hmac.c,v 1.21 2014/07/11 08:44:48 jsing Exp $ */ 2 /* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com) 3 * All rights reserved. 4 * 5 * This package is an SSL implementation written 6 * by Eric Young (eay@cryptsoft.com). 7 * The implementation was written so as to conform with Netscapes SSL. 8 * 9 * This library is free for commercial and non-commercial use as long as 10 * the following conditions are aheared to. The following conditions 11 * apply to all code found in this distribution, be it the RC4, RSA, 12 * lhash, DES, etc., code; not just the SSL code. The SSL documentation 13 * included with this distribution is covered by the same copyright terms 14 * except that the holder is Tim Hudson (tjh@cryptsoft.com). 15 * 16 * Copyright remains Eric Young's, and as such any Copyright notices in 17 * the code are not to be removed. 18 * If this package is used in a product, Eric Young should be given attribution 19 * as the author of the parts of the library used. 20 * This can be in the form of a textual message at program startup or 21 * in documentation (online or textual) provided with the package. 22 * 23 * Redistribution and use in source and binary forms, with or without 24 * modification, are permitted provided that the following conditions 25 * are met: 26 * 1. Redistributions of source code must retain the copyright 27 * notice, this list of conditions and the following disclaimer. 28 * 2. Redistributions in binary form must reproduce the above copyright 29 * notice, this list of conditions and the following disclaimer in the 30 * documentation and/or other materials provided with the distribution. 31 * 3. All advertising materials mentioning features or use of this software 32 * must display the following acknowledgement: 33 * "This product includes cryptographic software written by 34 * Eric Young (eay@cryptsoft.com)" 35 * The word 'cryptographic' can be left out if the rouines from the library 36 * being used are not cryptographic related :-). 37 * 4. If you include any Windows specific code (or a derivative thereof) from 38 * the apps directory (application code) you must include an acknowledgement: 39 * "This product includes software written by Tim Hudson (tjh@cryptsoft.com)" 40 * 41 * THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``AS IS'' AND 42 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 43 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 44 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 45 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 46 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 47 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 48 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 49 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 50 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 51 * SUCH DAMAGE. 52 * 53 * The licence and distribution terms for any publically available version or 54 * derivative of this code cannot be changed. i.e. this code cannot simply be 55 * copied and put under another distribution licence 56 * [including the GNU Public Licence.] 57 */ 58 59 #include <stdio.h> 60 #include <stdlib.h> 61 #include <string.h> 62 63 #include <openssl/err.h> 64 #include <openssl/hmac.h> 65 66 int 67 HMAC_Init_ex(HMAC_CTX *ctx, const void *key, int len, const EVP_MD *md, 68 ENGINE *impl) 69 { 70 int i, j, reset = 0; 71 unsigned char pad[HMAC_MAX_MD_CBLOCK]; 72 73 if (md != NULL) { 74 reset = 1; 75 ctx->md = md; 76 } else 77 md = ctx->md; 78 79 if (key != NULL) { 80 reset = 1; 81 j = EVP_MD_block_size(md); 82 if ((size_t)j > sizeof(ctx->key)) { 83 EVPerr(EVP_F_HMAC_INIT_EX, EVP_R_BAD_BLOCK_LENGTH); 84 goto err; 85 } 86 if (j < len) { 87 if (!EVP_DigestInit_ex(&ctx->md_ctx, md, impl)) 88 goto err; 89 if (!EVP_DigestUpdate(&ctx->md_ctx, key, len)) 90 goto err; 91 if (!EVP_DigestFinal_ex(&(ctx->md_ctx), ctx->key, 92 &ctx->key_length)) 93 goto err; 94 } else { 95 if ((size_t)len > sizeof(ctx->key)) { 96 EVPerr(EVP_F_HMAC_INIT_EX, 97 EVP_R_BAD_KEY_LENGTH); 98 goto err; 99 } 100 memcpy(ctx->key, key, len); 101 ctx->key_length = len; 102 } 103 if (ctx->key_length != HMAC_MAX_MD_CBLOCK) 104 memset(&ctx->key[ctx->key_length], 0, 105 HMAC_MAX_MD_CBLOCK - ctx->key_length); 106 } 107 108 if (reset) { 109 for (i = 0; i < HMAC_MAX_MD_CBLOCK; i++) 110 pad[i] = 0x36 ^ ctx->key[i]; 111 if (!EVP_DigestInit_ex(&ctx->i_ctx, md, impl)) 112 goto err; 113 if (!EVP_DigestUpdate(&ctx->i_ctx, pad, EVP_MD_block_size(md))) 114 goto err; 115 116 for (i = 0; i < HMAC_MAX_MD_CBLOCK; i++) 117 pad[i] = 0x5c ^ ctx->key[i]; 118 if (!EVP_DigestInit_ex(&ctx->o_ctx, md, impl)) 119 goto err; 120 if (!EVP_DigestUpdate(&ctx->o_ctx, pad, EVP_MD_block_size(md))) 121 goto err; 122 } 123 if (!EVP_MD_CTX_copy_ex(&ctx->md_ctx, &ctx->i_ctx)) 124 goto err; 125 return 1; 126 err: 127 return 0; 128 } 129 130 int 131 HMAC_Init(HMAC_CTX *ctx, const void *key, int len, const EVP_MD *md) 132 { 133 if (key && md) 134 HMAC_CTX_init(ctx); 135 return HMAC_Init_ex(ctx, key, len, md, NULL); 136 } 137 138 int 139 HMAC_Update(HMAC_CTX *ctx, const unsigned char *data, size_t len) 140 { 141 return EVP_DigestUpdate(&ctx->md_ctx, data, len); 142 } 143 144 int 145 HMAC_Final(HMAC_CTX *ctx, unsigned char *md, unsigned int *len) 146 { 147 unsigned int i; 148 unsigned char buf[EVP_MAX_MD_SIZE]; 149 150 if (!EVP_DigestFinal_ex(&ctx->md_ctx, buf, &i)) 151 goto err; 152 if (!EVP_MD_CTX_copy_ex(&ctx->md_ctx, &ctx->o_ctx)) 153 goto err; 154 if (!EVP_DigestUpdate(&ctx->md_ctx, buf, i)) 155 goto err; 156 if (!EVP_DigestFinal_ex(&ctx->md_ctx, md, len)) 157 goto err; 158 return 1; 159 err: 160 return 0; 161 } 162 163 void 164 HMAC_CTX_init(HMAC_CTX *ctx) 165 { 166 EVP_MD_CTX_init(&ctx->i_ctx); 167 EVP_MD_CTX_init(&ctx->o_ctx); 168 EVP_MD_CTX_init(&ctx->md_ctx); 169 } 170 171 int 172 HMAC_CTX_copy(HMAC_CTX *dctx, HMAC_CTX *sctx) 173 { 174 if (!EVP_MD_CTX_copy(&dctx->i_ctx, &sctx->i_ctx)) 175 goto err; 176 if (!EVP_MD_CTX_copy(&dctx->o_ctx, &sctx->o_ctx)) 177 goto err; 178 if (!EVP_MD_CTX_copy(&dctx->md_ctx, &sctx->md_ctx)) 179 goto err; 180 memcpy(dctx->key, sctx->key, HMAC_MAX_MD_CBLOCK); 181 dctx->key_length = sctx->key_length; 182 dctx->md = sctx->md; 183 return 1; 184 err: 185 return 0; 186 } 187 188 void 189 HMAC_CTX_cleanup(HMAC_CTX *ctx) 190 { 191 EVP_MD_CTX_cleanup(&ctx->i_ctx); 192 EVP_MD_CTX_cleanup(&ctx->o_ctx); 193 EVP_MD_CTX_cleanup(&ctx->md_ctx); 194 memset(ctx, 0, sizeof *ctx); 195 } 196 197 unsigned char * 198 HMAC(const EVP_MD *evp_md, const void *key, int key_len, const unsigned char *d, 199 size_t n, unsigned char *md, unsigned int *md_len) 200 { 201 HMAC_CTX c; 202 static unsigned char m[EVP_MAX_MD_SIZE]; 203 204 if (md == NULL) 205 md = m; 206 HMAC_CTX_init(&c); 207 if (!HMAC_Init(&c, key, key_len, evp_md)) 208 goto err; 209 if (!HMAC_Update(&c, d, n)) 210 goto err; 211 if (!HMAC_Final(&c, md, md_len)) 212 goto err; 213 HMAC_CTX_cleanup(&c); 214 return md; 215 err: 216 return NULL; 217 } 218 219 void 220 HMAC_CTX_set_flags(HMAC_CTX *ctx, unsigned long flags) 221 { 222 EVP_MD_CTX_set_flags(&ctx->i_ctx, flags); 223 EVP_MD_CTX_set_flags(&ctx->o_ctx, flags); 224 EVP_MD_CTX_set_flags(&ctx->md_ctx, flags); 225 } 226