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 static uint8_t static_out_buffer[EVP_MAX_MD_SIZE]; 73 74 /* OpenSSL has traditionally supported using a static buffer if |out| is 75 * NULL. We maintain that but don't document it. This behaviour should be 76 * considered to be deprecated. */ 77 if (out == NULL) { 78 out = static_out_buffer; 79 } 80 81 HMAC_CTX_init(&ctx); 82 if (!HMAC_Init_ex(&ctx, key, key_len, evp_md, NULL) || 83 !HMAC_Update(&ctx, data, data_len) || 84 !HMAC_Final(&ctx, out, out_len)) { 85 out = NULL; 86 } 87 88 HMAC_CTX_cleanup(&ctx); 89 return out; 90 } 91 92 void HMAC_CTX_init(HMAC_CTX *ctx) { 93 ctx->md = NULL; 94 EVP_MD_CTX_init(&ctx->i_ctx); 95 EVP_MD_CTX_init(&ctx->o_ctx); 96 EVP_MD_CTX_init(&ctx->md_ctx); 97 } 98 99 void HMAC_CTX_cleanup(HMAC_CTX *ctx) { 100 EVP_MD_CTX_cleanup(&ctx->i_ctx); 101 EVP_MD_CTX_cleanup(&ctx->o_ctx); 102 EVP_MD_CTX_cleanup(&ctx->md_ctx); 103 OPENSSL_cleanse(ctx, sizeof(HMAC_CTX)); 104 } 105 106 int HMAC_Init_ex(HMAC_CTX *ctx, const void *key, size_t key_len, 107 const EVP_MD *md, ENGINE *impl) { 108 if (md == NULL) { 109 md = ctx->md; 110 } 111 112 /* If either |key| is non-NULL or |md| has changed, initialize with a new key 113 * rather than rewinding the previous one. 114 * 115 * TODO(davidben,eroman): Passing the previous |md| with a NULL |key| is 116 * ambiguous between using the empty key and reusing the previous key. There 117 * exist callers which intend the latter, but the former is an awkward edge 118 * case. Fix to API to avoid this. */ 119 if (md != ctx->md || key != NULL) { 120 uint8_t pad[EVP_MAX_MD_BLOCK_SIZE]; 121 uint8_t key_block[EVP_MAX_MD_BLOCK_SIZE]; 122 unsigned key_block_len; 123 124 size_t block_size = EVP_MD_block_size(md); 125 assert(block_size <= sizeof(key_block)); 126 if (block_size < key_len) { 127 /* Long keys are hashed. */ 128 if (!EVP_DigestInit_ex(&ctx->md_ctx, md, impl) || 129 !EVP_DigestUpdate(&ctx->md_ctx, key, key_len) || 130 !EVP_DigestFinal_ex(&ctx->md_ctx, key_block, &key_block_len)) { 131 return 0; 132 } 133 } else { 134 assert(key_len <= sizeof(key_block)); 135 OPENSSL_memcpy(key_block, key, key_len); 136 key_block_len = (unsigned)key_len; 137 } 138 /* Keys are then padded with zeros. */ 139 if (key_block_len != EVP_MAX_MD_BLOCK_SIZE) { 140 OPENSSL_memset(&key_block[key_block_len], 0, sizeof(key_block) - key_block_len); 141 } 142 143 for (size_t i = 0; i < EVP_MAX_MD_BLOCK_SIZE; i++) { 144 pad[i] = 0x36 ^ key_block[i]; 145 } 146 if (!EVP_DigestInit_ex(&ctx->i_ctx, md, impl) || 147 !EVP_DigestUpdate(&ctx->i_ctx, pad, EVP_MD_block_size(md))) { 148 return 0; 149 } 150 151 for (size_t i = 0; i < EVP_MAX_MD_BLOCK_SIZE; i++) { 152 pad[i] = 0x5c ^ key_block[i]; 153 } 154 if (!EVP_DigestInit_ex(&ctx->o_ctx, md, impl) || 155 !EVP_DigestUpdate(&ctx->o_ctx, pad, EVP_MD_block_size(md))) { 156 return 0; 157 } 158 159 ctx->md = md; 160 } 161 162 if (!EVP_MD_CTX_copy_ex(&ctx->md_ctx, &ctx->i_ctx)) { 163 return 0; 164 } 165 166 return 1; 167 } 168 169 int HMAC_Update(HMAC_CTX *ctx, const uint8_t *data, size_t data_len) { 170 return EVP_DigestUpdate(&ctx->md_ctx, data, data_len); 171 } 172 173 int HMAC_Final(HMAC_CTX *ctx, uint8_t *out, unsigned int *out_len) { 174 unsigned int i; 175 uint8_t buf[EVP_MAX_MD_SIZE]; 176 177 /* TODO(davidben): The only thing that can officially fail here is 178 * |EVP_MD_CTX_copy_ex|, but even that should be impossible in this case. */ 179 if (!EVP_DigestFinal_ex(&ctx->md_ctx, buf, &i) || 180 !EVP_MD_CTX_copy_ex(&ctx->md_ctx, &ctx->o_ctx) || 181 !EVP_DigestUpdate(&ctx->md_ctx, buf, i) || 182 !EVP_DigestFinal_ex(&ctx->md_ctx, out, out_len)) { 183 *out_len = 0; 184 return 0; 185 } 186 187 return 1; 188 } 189 190 size_t HMAC_size(const HMAC_CTX *ctx) { 191 return EVP_MD_size(ctx->md); 192 } 193 194 int HMAC_CTX_copy_ex(HMAC_CTX *dest, const HMAC_CTX *src) { 195 if (!EVP_MD_CTX_copy_ex(&dest->i_ctx, &src->i_ctx) || 196 !EVP_MD_CTX_copy_ex(&dest->o_ctx, &src->o_ctx) || 197 !EVP_MD_CTX_copy_ex(&dest->md_ctx, &src->md_ctx)) { 198 return 0; 199 } 200 201 dest->md = src->md; 202 return 1; 203 } 204 205 int HMAC_Init(HMAC_CTX *ctx, const void *key, int key_len, const EVP_MD *md) { 206 if (key && md) { 207 HMAC_CTX_init(ctx); 208 } 209 return HMAC_Init_ex(ctx, key, key_len, md, NULL); 210 } 211 212 int HMAC_CTX_copy(HMAC_CTX *dest, const HMAC_CTX *src) { 213 HMAC_CTX_init(dest); 214 return HMAC_CTX_copy_ex(dest, src); 215 } 216
