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/mem.h> 63 64 65 uint8_t *HMAC(const EVP_MD *evp_md, const void *key, size_t key_len, 66 const uint8_t *data, size_t data_len, uint8_t *out, 67 unsigned int *out_len) { 68 HMAC_CTX ctx; 69 static uint8_t static_out_buffer[EVP_MAX_MD_SIZE]; 70 71 /* OpenSSL has traditionally supported using a static buffer if |out| is 72 * NULL. We maintain that but don't document it. This behaviour should be 73 * considered to be deprecated. */ 74 if (out == NULL) { 75 out = static_out_buffer; 76 } 77 78 HMAC_CTX_init(&ctx); 79 if (!HMAC_Init_ex(&ctx, key, key_len, evp_md, NULL) || 80 !HMAC_Update(&ctx, data, data_len) || 81 !HMAC_Final(&ctx, out, out_len)) { 82 out = NULL; 83 } 84 85 HMAC_CTX_cleanup(&ctx); 86 return out; 87 } 88 89 void HMAC_CTX_init(HMAC_CTX *ctx) { 90 ctx->md = NULL; 91 EVP_MD_CTX_init(&ctx->i_ctx); 92 EVP_MD_CTX_init(&ctx->o_ctx); 93 EVP_MD_CTX_init(&ctx->md_ctx); 94 } 95 96 void HMAC_CTX_cleanup(HMAC_CTX *ctx) { 97 EVP_MD_CTX_cleanup(&ctx->i_ctx); 98 EVP_MD_CTX_cleanup(&ctx->o_ctx); 99 EVP_MD_CTX_cleanup(&ctx->md_ctx); 100 OPENSSL_cleanse(ctx, sizeof(ctx)); 101 } 102 103 int HMAC_Init_ex(HMAC_CTX *ctx, const void *key, size_t key_len, 104 const EVP_MD *md, ENGINE *impl) { 105 if (md == NULL) { 106 md = ctx->md; 107 } 108 109 /* If either |key| is non-NULL or |md| has changed, initialize with a new key 110 * rather than rewinding the previous one. 111 * 112 * TODO(davidben,eroman): Passing the previous |md| with a NULL |key| is 113 * ambiguous between using the empty key and reusing the previous key. There 114 * exist callers which intend the latter, but the former is an awkward edge 115 * case. Fix to API to avoid this. */ 116 if (md != ctx->md || key != NULL) { 117 size_t i; 118 uint8_t pad[HMAC_MAX_MD_CBLOCK]; 119 uint8_t key_block[HMAC_MAX_MD_CBLOCK]; 120 unsigned key_block_len; 121 122 size_t block_size = EVP_MD_block_size(md); 123 assert(block_size <= sizeof(key_block)); 124 if (block_size < key_len) { 125 /* Long keys are hashed. */ 126 if (!EVP_DigestInit_ex(&ctx->md_ctx, md, impl) || 127 !EVP_DigestUpdate(&ctx->md_ctx, key, key_len) || 128 !EVP_DigestFinal_ex(&ctx->md_ctx, key_block, &key_block_len)) { 129 return 0; 130 } 131 } else { 132 assert(key_len >= 0 && key_len <= sizeof(key_block)); 133 memcpy(key_block, key, key_len); 134 key_block_len = (unsigned)key_len; 135 } 136 /* Keys are then padded with zeros. */ 137 if (key_block_len != HMAC_MAX_MD_CBLOCK) { 138 memset(&key_block[key_block_len], 0, sizeof(key_block) - key_block_len); 139 } 140 141 for (i = 0; i < HMAC_MAX_MD_CBLOCK; i++) { 142 pad[i] = 0x36 ^ key_block[i]; 143 } 144 if (!EVP_DigestInit_ex(&ctx->i_ctx, md, impl) || 145 !EVP_DigestUpdate(&ctx->i_ctx, pad, EVP_MD_block_size(md))) { 146 return 0; 147 } 148 149 for (i = 0; i < HMAC_MAX_MD_CBLOCK; i++) { 150 pad[i] = 0x5c ^ key_block[i]; 151 } 152 if (!EVP_DigestInit_ex(&ctx->o_ctx, md, impl) || 153 !EVP_DigestUpdate(&ctx->o_ctx, pad, EVP_MD_block_size(md))) { 154 return 0; 155 } 156 157 ctx->md = md; 158 } 159 160 if (!EVP_MD_CTX_copy_ex(&ctx->md_ctx, &ctx->i_ctx)) { 161 return 0; 162 } 163 164 return 1; 165 } 166 167 int HMAC_Update(HMAC_CTX *ctx, const uint8_t *data, size_t data_len) { 168 return EVP_DigestUpdate(&ctx->md_ctx, data, data_len); 169 } 170 171 int HMAC_Final(HMAC_CTX *ctx, uint8_t *out, unsigned int *out_len) { 172 unsigned int i; 173 uint8_t buf[EVP_MAX_MD_SIZE]; 174 175 /* TODO(davidben): The only thing that can officially fail here is 176 * |EVP_MD_CTX_copy_ex|, but even that should be impossible in this case. */ 177 if (!EVP_DigestFinal_ex(&ctx->md_ctx, buf, &i) || 178 !EVP_MD_CTX_copy_ex(&ctx->md_ctx, &ctx->o_ctx) || 179 !EVP_DigestUpdate(&ctx->md_ctx, buf, i) || 180 !EVP_DigestFinal_ex(&ctx->md_ctx, out, out_len)) { 181 *out_len = 0; 182 return 0; 183 } 184 185 return 1; 186 } 187 188 size_t HMAC_size(const HMAC_CTX *ctx) { 189 return EVP_MD_size(ctx->md); 190 } 191 192 int HMAC_CTX_copy_ex(HMAC_CTX *dest, const HMAC_CTX *src) { 193 if (!EVP_MD_CTX_copy_ex(&dest->i_ctx, &src->i_ctx) || 194 !EVP_MD_CTX_copy_ex(&dest->o_ctx, &src->o_ctx) || 195 !EVP_MD_CTX_copy_ex(&dest->md_ctx, &src->md_ctx)) { 196 return 0; 197 } 198 199 dest->md = src->md; 200 return 1; 201 } 202 203 int HMAC_Init(HMAC_CTX *ctx, const void *key, int key_len, const EVP_MD *md) { 204 if (key && md) { 205 HMAC_CTX_init(ctx); 206 } 207 return HMAC_Init_ex(ctx, key, key_len, md, NULL); 208 } 209 210 int HMAC_CTX_copy(HMAC_CTX *dest, const HMAC_CTX *src) { 211 HMAC_CTX_init(dest); 212 return HMAC_CTX_copy_ex(dest, src); 213 } 214
