1 /* Copyright (C) 1995-1998 Eric Young (eay (at) cryptsoft.com) 2 * All rights reserved. 3 * 4 * This package is an SSL implementation written 5 * by Eric Young (eay (at) cryptsoft.com). 6 * The implementation was written so as to conform with Netscapes SSL. 7 * 8 * This library is free for commercial and non-commercial use as long as 9 * the following conditions are aheared to. The following conditions 10 * apply to all code found in this distribution, be it the RC4, RSA, 11 * lhash, DES, etc., code; not just the SSL code. The SSL documentation 12 * included with this distribution is covered by the same copyright terms 13 * except that the holder is Tim Hudson (tjh (at) cryptsoft.com). 14 * 15 * Copyright remains Eric Young's, and as such any Copyright notices in 16 * the code are not to be removed. 17 * If this package is used in a product, Eric Young should be given attribution 18 * as the author of the parts of the library used. 19 * This can be in the form of a textual message at program startup or 20 * in documentation (online or textual) provided with the package. 21 * 22 * Redistribution and use in source and binary forms, with or without 23 * modification, are permitted provided that the following conditions 24 * are met: 25 * 1. Redistributions of source code must retain the copyright 26 * notice, this list of conditions and the following disclaimer. 27 * 2. Redistributions in binary form must reproduce the above copyright 28 * notice, this list of conditions and the following disclaimer in the 29 * documentation and/or other materials provided with the distribution. 30 * 3. All advertising materials mentioning features or use of this software 31 * must display the following acknowledgement: 32 * "This product includes cryptographic software written by 33 * Eric Young (eay (at) cryptsoft.com)" 34 * The word 'cryptographic' can be left out if the rouines from the library 35 * being used are not cryptographic related :-). 36 * 4. If you include any Windows specific code (or a derivative thereof) from 37 * the apps directory (application code) you must include an acknowledgement: 38 * "This product includes software written by Tim Hudson (tjh (at) cryptsoft.com)" 39 * 40 * THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``AS IS'' AND 41 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 42 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 43 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 44 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 45 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 46 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 47 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 48 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 49 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 50 * SUCH DAMAGE. 51 * 52 * The licence and distribution terms for any publically available version or 53 * derivative of this code cannot be changed. i.e. this code cannot simply be 54 * copied and put under another distribution licence 55 * [including the GNU Public Licence.] */ 56 57 #include <openssl/hmac.h> 58 59 #include <assert.h> 60 #include <string.h> 61 62 #include <openssl/digest.h> 63 #include <openssl/mem.h> 64 65 #include "../../internal.h" 66 67 68 uint8_t *HMAC(const EVP_MD *evp_md, const void *key, size_t key_len, 69 const uint8_t *data, size_t data_len, uint8_t *out, 70 unsigned int *out_len) { 71 HMAC_CTX ctx; 72 HMAC_CTX_init(&ctx); 73 if (!HMAC_Init_ex(&ctx, key, key_len, evp_md, NULL) || 74 !HMAC_Update(&ctx, data, data_len) || 75 !HMAC_Final(&ctx, out, out_len)) { 76 out = NULL; 77 } 78 79 HMAC_CTX_cleanup(&ctx); 80 return out; 81 } 82 83 void HMAC_CTX_init(HMAC_CTX *ctx) { 84 ctx->md = NULL; 85 EVP_MD_CTX_init(&ctx->i_ctx); 86 EVP_MD_CTX_init(&ctx->o_ctx); 87 EVP_MD_CTX_init(&ctx->md_ctx); 88 } 89 90 HMAC_CTX *HMAC_CTX_new(void) { 91 HMAC_CTX *ctx = OPENSSL_malloc(sizeof(HMAC_CTX)); 92 if (ctx != NULL) { 93 HMAC_CTX_init(ctx); 94 } 95 return ctx; 96 } 97 98 void HMAC_CTX_cleanup(HMAC_CTX *ctx) { 99 EVP_MD_CTX_cleanup(&ctx->i_ctx); 100 EVP_MD_CTX_cleanup(&ctx->o_ctx); 101 EVP_MD_CTX_cleanup(&ctx->md_ctx); 102 OPENSSL_cleanse(ctx, sizeof(HMAC_CTX)); 103 } 104 105 void HMAC_CTX_free(HMAC_CTX *ctx) { 106 if (ctx == NULL) { 107 return; 108 } 109 110 HMAC_CTX_cleanup(ctx); 111 OPENSSL_free(ctx); 112 } 113 114 int HMAC_Init_ex(HMAC_CTX *ctx, const void *key, size_t key_len, 115 const EVP_MD *md, ENGINE *impl) { 116 if (md == NULL) { 117 md = ctx->md; 118 } 119 120 // If either |key| is non-NULL or |md| has changed, initialize with a new key 121 // rather than rewinding the previous one. 122 // 123 // TODO(davidben,eroman): Passing the previous |md| with a NULL |key| is 124 // ambiguous between using the empty key and reusing the previous key. There 125 // exist callers which intend the latter, but the former is an awkward edge 126 // case. Fix to API to avoid this. 127 if (md != ctx->md || key != NULL) { 128 uint8_t pad[EVP_MAX_MD_BLOCK_SIZE]; 129 uint8_t key_block[EVP_MAX_MD_BLOCK_SIZE]; 130 unsigned key_block_len; 131 132 size_t block_size = EVP_MD_block_size(md); 133 assert(block_size <= sizeof(key_block)); 134 if (block_size < key_len) { 135 // Long keys are hashed. 136 if (!EVP_DigestInit_ex(&ctx->md_ctx, md, impl) || 137 !EVP_DigestUpdate(&ctx->md_ctx, key, key_len) || 138 !EVP_DigestFinal_ex(&ctx->md_ctx, key_block, &key_block_len)) { 139 return 0; 140 } 141 } else { 142 assert(key_len <= sizeof(key_block)); 143 OPENSSL_memcpy(key_block, key, key_len); 144 key_block_len = (unsigned)key_len; 145 } 146 // Keys are then padded with zeros. 147 if (key_block_len != EVP_MAX_MD_BLOCK_SIZE) { 148 OPENSSL_memset(&key_block[key_block_len], 0, sizeof(key_block) - key_block_len); 149 } 150 151 for (size_t i = 0; i < EVP_MAX_MD_BLOCK_SIZE; i++) { 152 pad[i] = 0x36 ^ key_block[i]; 153 } 154 if (!EVP_DigestInit_ex(&ctx->i_ctx, md, impl) || 155 !EVP_DigestUpdate(&ctx->i_ctx, pad, EVP_MD_block_size(md))) { 156 return 0; 157 } 158 159 for (size_t i = 0; i < EVP_MAX_MD_BLOCK_SIZE; i++) { 160 pad[i] = 0x5c ^ key_block[i]; 161 } 162 if (!EVP_DigestInit_ex(&ctx->o_ctx, md, impl) || 163 !EVP_DigestUpdate(&ctx->o_ctx, pad, EVP_MD_block_size(md))) { 164 return 0; 165 } 166 167 ctx->md = md; 168 } 169 170 if (!EVP_MD_CTX_copy_ex(&ctx->md_ctx, &ctx->i_ctx)) { 171 return 0; 172 } 173 174 return 1; 175 } 176 177 int HMAC_Update(HMAC_CTX *ctx, const uint8_t *data, size_t data_len) { 178 return EVP_DigestUpdate(&ctx->md_ctx, data, data_len); 179 } 180 181 int HMAC_Final(HMAC_CTX *ctx, uint8_t *out, unsigned int *out_len) { 182 unsigned int i; 183 uint8_t buf[EVP_MAX_MD_SIZE]; 184 185 // TODO(davidben): The only thing that can officially fail here is 186 // |EVP_MD_CTX_copy_ex|, but even that should be impossible in this case. 187 if (!EVP_DigestFinal_ex(&ctx->md_ctx, buf, &i) || 188 !EVP_MD_CTX_copy_ex(&ctx->md_ctx, &ctx->o_ctx) || 189 !EVP_DigestUpdate(&ctx->md_ctx, buf, i) || 190 !EVP_DigestFinal_ex(&ctx->md_ctx, out, out_len)) { 191 *out_len = 0; 192 return 0; 193 } 194 195 return 1; 196 } 197 198 size_t HMAC_size(const HMAC_CTX *ctx) { 199 return EVP_MD_size(ctx->md); 200 } 201 202 int HMAC_CTX_copy_ex(HMAC_CTX *dest, const HMAC_CTX *src) { 203 if (!EVP_MD_CTX_copy_ex(&dest->i_ctx, &src->i_ctx) || 204 !EVP_MD_CTX_copy_ex(&dest->o_ctx, &src->o_ctx) || 205 !EVP_MD_CTX_copy_ex(&dest->md_ctx, &src->md_ctx)) { 206 return 0; 207 } 208 209 dest->md = src->md; 210 return 1; 211 } 212 213 void HMAC_CTX_reset(HMAC_CTX *ctx) { 214 HMAC_CTX_cleanup(ctx); 215 HMAC_CTX_init(ctx); 216 } 217 218 int HMAC_Init(HMAC_CTX *ctx, const void *key, int key_len, const EVP_MD *md) { 219 if (key && md) { 220 HMAC_CTX_init(ctx); 221 } 222 return HMAC_Init_ex(ctx, key, key_len, md, NULL); 223 } 224 225 int HMAC_CTX_copy(HMAC_CTX *dest, const HMAC_CTX *src) { 226 HMAC_CTX_init(dest); 227 return HMAC_CTX_copy_ex(dest, src); 228 } 229
