1 /* $OpenBSD: hmac.c,v 1.25 2018/02/17 14:53:58 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 we are changing MD then we must have a key */ 74 if (md != NULL && md != ctx->md && (key == NULL || len < 0)) 75 return 0; 76 77 if (md != NULL) { 78 reset = 1; 79 ctx->md = md; 80 } else if (ctx->md != NULL) 81 md = ctx->md; 82 else 83 return 0; 84 85 if (key != NULL) { 86 reset = 1; 87 j = EVP_MD_block_size(md); 88 if ((size_t)j > sizeof(ctx->key)) { 89 EVPerror(EVP_R_BAD_BLOCK_LENGTH); 90 goto err; 91 } 92 if (j < len) { 93 if (!EVP_DigestInit_ex(&ctx->md_ctx, md, impl)) 94 goto err; 95 if (!EVP_DigestUpdate(&ctx->md_ctx, key, len)) 96 goto err; 97 if (!EVP_DigestFinal_ex(&(ctx->md_ctx), ctx->key, 98 &ctx->key_length)) 99 goto err; 100 } else { 101 if (len < 0 || (size_t)len > sizeof(ctx->key)) { 102 EVPerror(EVP_R_BAD_KEY_LENGTH); 103 goto err; 104 } 105 memcpy(ctx->key, key, len); 106 ctx->key_length = len; 107 } 108 if (ctx->key_length != HMAC_MAX_MD_CBLOCK) 109 memset(&ctx->key[ctx->key_length], 0, 110 HMAC_MAX_MD_CBLOCK - ctx->key_length); 111 } 112 113 if (reset) { 114 for (i = 0; i < HMAC_MAX_MD_CBLOCK; i++) 115 pad[i] = 0x36 ^ ctx->key[i]; 116 if (!EVP_DigestInit_ex(&ctx->i_ctx, md, impl)) 117 goto err; 118 if (!EVP_DigestUpdate(&ctx->i_ctx, pad, EVP_MD_block_size(md))) 119 goto err; 120 121 for (i = 0; i < HMAC_MAX_MD_CBLOCK; i++) 122 pad[i] = 0x5c ^ ctx->key[i]; 123 if (!EVP_DigestInit_ex(&ctx->o_ctx, md, impl)) 124 goto err; 125 if (!EVP_DigestUpdate(&ctx->o_ctx, pad, EVP_MD_block_size(md))) 126 goto err; 127 } 128 if (!EVP_MD_CTX_copy_ex(&ctx->md_ctx, &ctx->i_ctx)) 129 goto err; 130 return 1; 131 err: 132 return 0; 133 } 134 135 int 136 HMAC_Init(HMAC_CTX *ctx, const void *key, int len, const EVP_MD *md) 137 { 138 if (key && md) 139 HMAC_CTX_init(ctx); 140 return HMAC_Init_ex(ctx, key, len, md, NULL); 141 } 142 143 int 144 HMAC_Update(HMAC_CTX *ctx, const unsigned char *data, size_t len) 145 { 146 if (ctx->md == NULL) 147 return 0; 148 149 return EVP_DigestUpdate(&ctx->md_ctx, data, len); 150 } 151 152 int 153 HMAC_Final(HMAC_CTX *ctx, unsigned char *md, unsigned int *len) 154 { 155 unsigned int i; 156 unsigned char buf[EVP_MAX_MD_SIZE]; 157 158 if (ctx->md == NULL) 159 goto err; 160 161 if (!EVP_DigestFinal_ex(&ctx->md_ctx, buf, &i)) 162 goto err; 163 if (!EVP_MD_CTX_copy_ex(&ctx->md_ctx, &ctx->o_ctx)) 164 goto err; 165 if (!EVP_DigestUpdate(&ctx->md_ctx, buf, i)) 166 goto err; 167 if (!EVP_DigestFinal_ex(&ctx->md_ctx, md, len)) 168 goto err; 169 return 1; 170 err: 171 return 0; 172 } 173 174 HMAC_CTX * 175 HMAC_CTX_new(void) 176 { 177 HMAC_CTX *ctx; 178 179 if ((ctx = calloc(1, sizeof(*ctx))) == NULL) 180 return NULL; 181 182 HMAC_CTX_init(ctx); 183 184 return ctx; 185 } 186 187 void 188 HMAC_CTX_free(HMAC_CTX *ctx) 189 { 190 if (ctx == NULL) 191 return; 192 193 HMAC_CTX_cleanup(ctx); 194 195 free(ctx); 196 } 197 198 int 199 HMAC_CTX_reset(HMAC_CTX *ctx) 200 { 201 HMAC_CTX_cleanup(ctx); 202 HMAC_CTX_init(ctx); 203 return 1; 204 } 205 206 void 207 HMAC_CTX_init(HMAC_CTX *ctx) 208 { 209 EVP_MD_CTX_init(&ctx->i_ctx); 210 EVP_MD_CTX_init(&ctx->o_ctx); 211 EVP_MD_CTX_init(&ctx->md_ctx); 212 ctx->md = NULL; 213 } 214 215 int 216 HMAC_CTX_copy(HMAC_CTX *dctx, HMAC_CTX *sctx) 217 { 218 if (!EVP_MD_CTX_copy(&dctx->i_ctx, &sctx->i_ctx)) 219 goto err; 220 if (!EVP_MD_CTX_copy(&dctx->o_ctx, &sctx->o_ctx)) 221 goto err; 222 if (!EVP_MD_CTX_copy(&dctx->md_ctx, &sctx->md_ctx)) 223 goto err; 224 memcpy(dctx->key, sctx->key, HMAC_MAX_MD_CBLOCK); 225 dctx->key_length = sctx->key_length; 226 dctx->md = sctx->md; 227 return 1; 228 err: 229 return 0; 230 } 231 232 void 233 HMAC_CTX_cleanup(HMAC_CTX *ctx) 234 { 235 EVP_MD_CTX_cleanup(&ctx->i_ctx); 236 EVP_MD_CTX_cleanup(&ctx->o_ctx); 237 EVP_MD_CTX_cleanup(&ctx->md_ctx); 238 explicit_bzero(ctx, sizeof(*ctx)); 239 } 240 241 void 242 HMAC_CTX_set_flags(HMAC_CTX *ctx, unsigned long flags) 243 { 244 EVP_MD_CTX_set_flags(&ctx->i_ctx, flags); 245 EVP_MD_CTX_set_flags(&ctx->o_ctx, flags); 246 EVP_MD_CTX_set_flags(&ctx->md_ctx, flags); 247 } 248 249 const EVP_MD * 250 HMAC_CTX_get_md(const HMAC_CTX *ctx) 251 { 252 return ctx->md; 253 } 254 255 unsigned char * 256 HMAC(const EVP_MD *evp_md, const void *key, int key_len, const unsigned char *d, 257 size_t n, unsigned char *md, unsigned int *md_len) 258 { 259 HMAC_CTX c; 260 static unsigned char m[EVP_MAX_MD_SIZE]; 261 262 if (md == NULL) 263 md = m; 264 HMAC_CTX_init(&c); 265 if (!HMAC_Init(&c, key, key_len, evp_md)) 266 goto err; 267 if (!HMAC_Update(&c, d, n)) 268 goto err; 269 if (!HMAC_Final(&c, md, md_len)) 270 goto err; 271 HMAC_CTX_cleanup(&c); 272 return md; 273 err: 274 HMAC_CTX_cleanup(&c); 275 return NULL; 276 } 277