crypto/hmac/hmac.c

   1 /* crypto/hmac/hmac.c */
   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 #include "cryptlib.h"
  63 #include <openssl/hmac.h>
  64
  65 int HMAC_Init_ex(HMAC_CTX *ctx, const void *key, int len,
  66                  const EVP_MD *md, ENGINE *impl)
  67 {
  68     int i, j, reset = 0;
  69     unsigned char pad[HMAC_MAX_MD_CBLOCK];
  70
  71     if (md != NULL) {
  72         reset = 1;
  73         ctx->md = md;
  74     } else if (ctx->md) {
  75         md = ctx->md;
  76     } else {
  77         return 0;
  78     }
  79
  80     if (!ctx->key_init && key == NULL)
  81         return 0;
  82
  83     if (key != NULL) {
  84         reset = 1;
  85         j = M_EVP_MD_block_size(md);
  86         OPENSSL_assert(j <= (int)sizeof(ctx->key));
  87         if (j < len) {
  88             if (!EVP_DigestInit_ex(&ctx->md_ctx, md, impl))
  89                 goto err;
  90             if (!EVP_DigestUpdate(&ctx->md_ctx, key, len))
  91                 goto err;
  92             if (!EVP_DigestFinal_ex(&(ctx->md_ctx), ctx->key,
  93                                     &ctx->key_length))
  94                 goto err;
  95         } else {
  96             if (len < 0 || len > (int)sizeof(ctx->key))
  97                 return 0;
  98             memcpy(ctx->key, key, len);
  99             ctx->key_length = len;
 100         }
 101         if (ctx->key_length != HMAC_MAX_MD_CBLOCK)
 102             memset(&ctx->key[ctx->key_length], 0,
 103                    HMAC_MAX_MD_CBLOCK - ctx->key_length);
 104         ctx->key_init = 1;
 105     }
 106
 107     if (reset) {
 108         for (i = 0; i < HMAC_MAX_MD_CBLOCK; i++)
 109             pad[i] = 0x36 ^ ctx->key[i];
 110         if (!EVP_DigestInit_ex(&ctx->i_ctx, md, impl))
 111             goto err;
 112         if (!EVP_DigestUpdate(&ctx->i_ctx, pad, M_EVP_MD_block_size(md)))
 113             goto err;
 114
 115         for (i = 0; i < HMAC_MAX_MD_CBLOCK; i++)
 116             pad[i] = 0x5c ^ ctx->key[i];
 117         if (!EVP_DigestInit_ex(&ctx->o_ctx, md, impl))
 118             goto err;
 119         if (!EVP_DigestUpdate(&ctx->o_ctx, pad, M_EVP_MD_block_size(md)))
 120             goto err;
 121     }
 122     if (!EVP_MD_CTX_copy_ex(&ctx->md_ctx, &ctx->i_ctx))
 123         goto err;
 124     return 1;
 125  err:
 126     return 0;
 127 }
 128
 129 #ifndef OPENSSL_NO_DEPRECATED
 130 int HMAC_Init(HMAC_CTX *ctx, const void *key, int len, const EVP_MD *md)
 131 {
 132     if (key && md)
 133         HMAC_CTX_init(ctx);
 134     return HMAC_Init_ex(ctx, key, len, md, NULL);
 135 }
 136 #endif
 137
 138 int HMAC_Update(HMAC_CTX *ctx, const unsigned char *data, size_t len)
 139 {
 140     if (!ctx->key_init)
 141         return 0;
 142     return EVP_DigestUpdate(&ctx->md_ctx, data, len);
 143 }
 144
 145 int HMAC_Final(HMAC_CTX *ctx, unsigned char *md, unsigned int *len)
 146 {
 147     unsigned int i;
 148     unsigned char buf[EVP_MAX_MD_SIZE];
 149
 150     if (!ctx->key_init)
 151         goto err;
 152
 153     if (!EVP_DigestFinal_ex(&ctx->md_ctx, buf, &i))
 154         goto err;
 155     if (!EVP_MD_CTX_copy_ex(&ctx->md_ctx, &ctx->o_ctx))
 156         goto err;
 157     if (!EVP_DigestUpdate(&ctx->md_ctx, buf, i))
 158         goto err;
 159     if (!EVP_DigestFinal_ex(&ctx->md_ctx, md, len))
 160         goto err;
 161     return 1;
 162  err:
 163     return 0;
 164 }
 165
 166 void HMAC_CTX_init(HMAC_CTX *ctx)
 167 {
 168     EVP_MD_CTX_init(&ctx->i_ctx);
 169     EVP_MD_CTX_init(&ctx->o_ctx);
 170     EVP_MD_CTX_init(&ctx->md_ctx);
 171     ctx->key_init = 0;
 172     ctx->md = NULL;
 173 }
 174
 175 int HMAC_CTX_copy(HMAC_CTX *dctx, HMAC_CTX *sctx)
 176 {
 177     HMAC_CTX_init(dctx);
 178     if (!EVP_MD_CTX_copy_ex(&dctx->i_ctx, &sctx->i_ctx))
 179         goto err;
 180     if (!EVP_MD_CTX_copy_ex(&dctx->o_ctx, &sctx->o_ctx))
 181         goto err;
 182     if (!EVP_MD_CTX_copy_ex(&dctx->md_ctx, &sctx->md_ctx))
 183         goto err;
 184     dctx->key_init = sctx->key_init;
 185     if (sctx->key_init) {
 186         memcpy(dctx->key, sctx->key, HMAC_MAX_MD_CBLOCK);
 187         dctx->key_length = sctx->key_length;
 188     }
 189     dctx->md = sctx->md;
 190     return 1;
 191  err:
 192     return 0;
 193 }
 194
 195 void HMAC_CTX_cleanup(HMAC_CTX *ctx)
 196 {
 197     EVP_MD_CTX_cleanup(&ctx->i_ctx);
 198     EVP_MD_CTX_cleanup(&ctx->o_ctx);
 199     EVP_MD_CTX_cleanup(&ctx->md_ctx);
 200     memset(ctx, 0, sizeof *ctx);
 201 }
 202
 203 unsigned char *HMAC(const EVP_MD *evp_md, const void *key, int key_len,
 204                     const unsigned char *d, size_t n, unsigned char *md,
 205                     unsigned int *md_len)
 206 {
 207     HMAC_CTX c;
 208     static unsigned char m[EVP_MAX_MD_SIZE];
 209
 210     if (md == NULL)
 211         md = m;
 212     HMAC_CTX_init(&c);
 213     if (!HMAC_Init_ex(&c, key, key_len, evp_md, NULL))
 214         goto err;
 215     if (!HMAC_Update(&c, d, n))
 216         goto err;
 217     if (!HMAC_Final(&c, md, md_len))
 218         goto err;
 219     HMAC_CTX_cleanup(&c);
 220     return md;
 221  err:
 222     return NULL;
 223 }
 224
 225 void HMAC_CTX_set_flags(HMAC_CTX *ctx, unsigned long flags)
 226 {
 227     M_EVP_MD_CTX_set_flags(&ctx->i_ctx, flags);
 228     M_EVP_MD_CTX_set_flags(&ctx->o_ctx, flags);
 229     M_EVP_MD_CTX_set_flags(&ctx->md_ctx, flags);
 230 }