1 /* $OpenBSD: hmac.c,v 1.28 2022/05/05 18:29:34 tb 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 #include "evp_locl.h" 67 #include "hmac_local.h" 68 69 int 70 HMAC_Init_ex(HMAC_CTX *ctx, const void *key, int len, const EVP_MD *md, 71 ENGINE *impl) 72 { 73 int i, j, reset = 0; 74 unsigned char pad[HMAC_MAX_MD_CBLOCK]; 75 76 /* If we are changing MD then we must have a key */ 77 if (md != NULL && md != ctx->md && (key == NULL || len < 0)) 78 return 0; 79 80 if (md != NULL) { 81 reset = 1; 82 ctx->md = md; 83 } else if (ctx->md != NULL) 84 md = ctx->md; 85 else 86 return 0; 87 88 if (key != NULL) { 89 reset = 1; 90 j = EVP_MD_block_size(md); 91 if ((size_t)j > sizeof(ctx->key)) { 92 EVPerror(EVP_R_BAD_BLOCK_LENGTH); 93 goto err; 94 } 95 if (j < len) { 96 if (!EVP_DigestInit_ex(&ctx->md_ctx, md, impl)) 97 goto err; 98 if (!EVP_DigestUpdate(&ctx->md_ctx, key, len)) 99 goto err; 100 if (!EVP_DigestFinal_ex(&(ctx->md_ctx), ctx->key, 101 &ctx->key_length)) 102 goto err; 103 } else { 104 if (len < 0 || (size_t)len > sizeof(ctx->key)) { 105 EVPerror(EVP_R_BAD_KEY_LENGTH); 106 goto err; 107 } 108 memcpy(ctx->key, key, len); 109 ctx->key_length = len; 110 } 111 if (ctx->key_length != HMAC_MAX_MD_CBLOCK) 112 memset(&ctx->key[ctx->key_length], 0, 113 HMAC_MAX_MD_CBLOCK - ctx->key_length); 114 } 115 116 if (reset) { 117 for (i = 0; i < HMAC_MAX_MD_CBLOCK; i++) 118 pad[i] = 0x36 ^ ctx->key[i]; 119 if (!EVP_DigestInit_ex(&ctx->i_ctx, md, impl)) 120 goto err; 121 if (!EVP_DigestUpdate(&ctx->i_ctx, pad, EVP_MD_block_size(md))) 122 goto err; 123 124 for (i = 0; i < HMAC_MAX_MD_CBLOCK; i++) 125 pad[i] = 0x5c ^ ctx->key[i]; 126 if (!EVP_DigestInit_ex(&ctx->o_ctx, md, impl)) 127 goto err; 128 if (!EVP_DigestUpdate(&ctx->o_ctx, pad, EVP_MD_block_size(md))) 129 goto err; 130 } 131 if (!EVP_MD_CTX_copy_ex(&ctx->md_ctx, &ctx->i_ctx)) 132 goto err; 133 return 1; 134 err: 135 return 0; 136 } 137 138 int 139 HMAC_Init(HMAC_CTX *ctx, const void *key, int len, const EVP_MD *md) 140 { 141 if (key && md) 142 HMAC_CTX_init(ctx); 143 return HMAC_Init_ex(ctx, key, len, md, NULL); 144 } 145 146 int 147 HMAC_Update(HMAC_CTX *ctx, const unsigned char *data, size_t len) 148 { 149 if (ctx->md == NULL) 150 return 0; 151 152 return EVP_DigestUpdate(&ctx->md_ctx, data, len); 153 } 154 155 int 156 HMAC_Final(HMAC_CTX *ctx, unsigned char *md, unsigned int *len) 157 { 158 unsigned int i; 159 unsigned char buf[EVP_MAX_MD_SIZE]; 160 161 if (ctx->md == NULL) 162 goto err; 163 164 if (!EVP_DigestFinal_ex(&ctx->md_ctx, buf, &i)) 165 goto err; 166 if (!EVP_MD_CTX_copy_ex(&ctx->md_ctx, &ctx->o_ctx)) 167 goto err; 168 if (!EVP_DigestUpdate(&ctx->md_ctx, buf, i)) 169 goto err; 170 if (!EVP_DigestFinal_ex(&ctx->md_ctx, md, len)) 171 goto err; 172 return 1; 173 err: 174 return 0; 175 } 176 177 HMAC_CTX * 178 HMAC_CTX_new(void) 179 { 180 HMAC_CTX *ctx; 181 182 if ((ctx = calloc(1, sizeof(*ctx))) == NULL) 183 return NULL; 184 185 HMAC_CTX_init(ctx); 186 187 return ctx; 188 } 189 190 void 191 HMAC_CTX_free(HMAC_CTX *ctx) 192 { 193 if (ctx == NULL) 194 return; 195 196 HMAC_CTX_cleanup(ctx); 197 198 free(ctx); 199 } 200 201 int 202 HMAC_CTX_reset(HMAC_CTX *ctx) 203 { 204 HMAC_CTX_cleanup(ctx); 205 HMAC_CTX_init(ctx); 206 return 1; 207 } 208 209 void 210 HMAC_CTX_init(HMAC_CTX *ctx) 211 { 212 EVP_MD_CTX_init(&ctx->i_ctx); 213 EVP_MD_CTX_init(&ctx->o_ctx); 214 EVP_MD_CTX_init(&ctx->md_ctx); 215 ctx->md = NULL; 216 } 217 218 int 219 HMAC_CTX_copy(HMAC_CTX *dctx, HMAC_CTX *sctx) 220 { 221 if (!EVP_MD_CTX_copy(&dctx->i_ctx, &sctx->i_ctx)) 222 goto err; 223 if (!EVP_MD_CTX_copy(&dctx->o_ctx, &sctx->o_ctx)) 224 goto err; 225 if (!EVP_MD_CTX_copy(&dctx->md_ctx, &sctx->md_ctx)) 226 goto err; 227 memcpy(dctx->key, sctx->key, HMAC_MAX_MD_CBLOCK); 228 dctx->key_length = sctx->key_length; 229 dctx->md = sctx->md; 230 return 1; 231 err: 232 return 0; 233 } 234 235 void 236 HMAC_CTX_cleanup(HMAC_CTX *ctx) 237 { 238 EVP_MD_CTX_cleanup(&ctx->i_ctx); 239 EVP_MD_CTX_cleanup(&ctx->o_ctx); 240 EVP_MD_CTX_cleanup(&ctx->md_ctx); 241 explicit_bzero(ctx, sizeof(*ctx)); 242 } 243 244 void 245 HMAC_CTX_set_flags(HMAC_CTX *ctx, unsigned long flags) 246 { 247 EVP_MD_CTX_set_flags(&ctx->i_ctx, flags); 248 EVP_MD_CTX_set_flags(&ctx->o_ctx, flags); 249 EVP_MD_CTX_set_flags(&ctx->md_ctx, flags); 250 } 251 252 const EVP_MD * 253 HMAC_CTX_get_md(const HMAC_CTX *ctx) 254 { 255 return ctx->md; 256 } 257 258 unsigned char * 259 HMAC(const EVP_MD *evp_md, const void *key, int key_len, const unsigned char *d, 260 size_t n, unsigned char *md, unsigned int *md_len) 261 { 262 HMAC_CTX c; 263 static unsigned char m[EVP_MAX_MD_SIZE]; 264 const unsigned char dummy_key[1] = { 0 }; 265 266 if (md == NULL) 267 md = m; 268 if (key == NULL) { 269 key = dummy_key; 270 key_len = 0; 271 } 272 HMAC_CTX_init(&c); 273 if (!HMAC_Init_ex(&c, key, key_len, evp_md, NULL)) 274 goto err; 275 if (!HMAC_Update(&c, d, n)) 276 goto err; 277 if (!HMAC_Final(&c, md, md_len)) 278 goto err; 279 HMAC_CTX_cleanup(&c); 280 return md; 281 err: 282 HMAC_CTX_cleanup(&c); 283 return NULL; 284 } 285