lib/libcrypto/hmac/hmac.c

   1 /* $OpenBSD: hmac.c,v 1.24 2017/03/03 10:39:07 inoguchi 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 int
  67 HMAC_Init_ex(HMAC_CTX *ctx, const void *key, int len, const EVP_MD *md,
  68     ENGINE *impl)
  69 {
  70         int i, j, reset = 0;
  71         unsigned char pad[HMAC_MAX_MD_CBLOCK];
  72
  73         /* If we are changing MD then we must have a key */
  74         if (md != NULL && md != ctx->md && (key == NULL || len < 0))
  75                 return 0;
  76
  77         if (md != NULL) {
  78                 reset = 1;
  79                 ctx->md = md;
  80         } else if (ctx->md != NULL)
  81                 md = ctx->md;
  82         else
  83                 return 0;
  84
  85         if (key != NULL) {
  86                 reset = 1;
  87                 j = EVP_MD_block_size(md);
  88                 if ((size_t)j > sizeof(ctx->key)) {
  89                         EVPerror(EVP_R_BAD_BLOCK_LENGTH);
  90                         goto err;
  91                 }
  92                 if (j < len) {
  93                         if (!EVP_DigestInit_ex(&ctx->md_ctx, md, impl))
  94                                 goto err;
  95                         if (!EVP_DigestUpdate(&ctx->md_ctx, key, len))
  96                                 goto err;
  97                         if (!EVP_DigestFinal_ex(&(ctx->md_ctx), ctx->key,
  98                             &ctx->key_length))
  99                                 goto err;
 100                 } else {
 101                         if (len < 0 || (size_t)len > sizeof(ctx->key)) {
 102                                 EVPerror(EVP_R_BAD_KEY_LENGTH);
 103                                 goto err;
 104                         }
 105                         memcpy(ctx->key, key, len);
 106                         ctx->key_length = len;
 107                 }
 108                 if (ctx->key_length != HMAC_MAX_MD_CBLOCK)
 109                         memset(&ctx->key[ctx->key_length], 0,
 110                             HMAC_MAX_MD_CBLOCK - ctx->key_length);
 111         }
 112
 113         if (reset) {
 114                 for (i = 0; i < HMAC_MAX_MD_CBLOCK; i++)
 115                         pad[i] = 0x36 ^ ctx->key[i];
 116                 if (!EVP_DigestInit_ex(&ctx->i_ctx, md, impl))
 117                         goto err;
 118                 if (!EVP_DigestUpdate(&ctx->i_ctx, pad, EVP_MD_block_size(md)))
 119                         goto err;
 120
 121                 for (i = 0; i < HMAC_MAX_MD_CBLOCK; i++)
 122                         pad[i] = 0x5c ^ ctx->key[i];
 123                 if (!EVP_DigestInit_ex(&ctx->o_ctx, md, impl))
 124                         goto err;
 125                 if (!EVP_DigestUpdate(&ctx->o_ctx, pad, EVP_MD_block_size(md)))
 126                         goto err;
 127         }
 128         if (!EVP_MD_CTX_copy_ex(&ctx->md_ctx, &ctx->i_ctx))
 129                 goto err;
 130         return 1;
 131 err:
 132         return 0;
 133 }
 134
 135 int
 136 HMAC_Init(HMAC_CTX *ctx, const void *key, int len, const EVP_MD *md)
 137 {
 138         if (key && md)
 139                 HMAC_CTX_init(ctx);
 140         return HMAC_Init_ex(ctx, key, len, md, NULL);
 141 }
 142
 143 int
 144 HMAC_Update(HMAC_CTX *ctx, const unsigned char *data, size_t len)
 145 {
 146         if (ctx->md == NULL)
 147                 return 0;
 148
 149         return EVP_DigestUpdate(&ctx->md_ctx, data, len);
 150 }
 151
 152 int
 153 HMAC_Final(HMAC_CTX *ctx, unsigned char *md, unsigned int *len)
 154 {
 155         unsigned int i;
 156         unsigned char buf[EVP_MAX_MD_SIZE];
 157
 158         if (ctx->md == NULL)
 159                 goto err;
 160
 161         if (!EVP_DigestFinal_ex(&ctx->md_ctx, buf, &i))
 162                 goto err;
 163         if (!EVP_MD_CTX_copy_ex(&ctx->md_ctx, &ctx->o_ctx))
 164                 goto err;
 165         if (!EVP_DigestUpdate(&ctx->md_ctx, buf, i))
 166                 goto err;
 167         if (!EVP_DigestFinal_ex(&ctx->md_ctx, md, len))
 168                 goto err;
 169         return 1;
 170 err:
 171         return 0;
 172 }
 173
 174 void
 175 HMAC_CTX_init(HMAC_CTX *ctx)
 176 {
 177         EVP_MD_CTX_init(&ctx->i_ctx);
 178         EVP_MD_CTX_init(&ctx->o_ctx);
 179         EVP_MD_CTX_init(&ctx->md_ctx);
 180         ctx->md = NULL;
 181 }
 182
 183 int
 184 HMAC_CTX_copy(HMAC_CTX *dctx, HMAC_CTX *sctx)
 185 {
 186         if (!EVP_MD_CTX_copy(&dctx->i_ctx, &sctx->i_ctx))
 187                 goto err;
 188         if (!EVP_MD_CTX_copy(&dctx->o_ctx, &sctx->o_ctx))
 189                 goto err;
 190         if (!EVP_MD_CTX_copy(&dctx->md_ctx, &sctx->md_ctx))
 191                 goto err;
 192         memcpy(dctx->key, sctx->key, HMAC_MAX_MD_CBLOCK);
 193         dctx->key_length = sctx->key_length;
 194         dctx->md = sctx->md;
 195         return 1;
 196 err:
 197         return 0;
 198 }
 199
 200 void
 201 HMAC_CTX_cleanup(HMAC_CTX *ctx)
 202 {
 203         EVP_MD_CTX_cleanup(&ctx->i_ctx);
 204         EVP_MD_CTX_cleanup(&ctx->o_ctx);
 205         EVP_MD_CTX_cleanup(&ctx->md_ctx);
 206         explicit_bzero(ctx, sizeof(*ctx));
 207 }
 208
 209 unsigned char *
 210 HMAC(const EVP_MD *evp_md, const void *key, int key_len, const unsigned char *d,
 211     size_t n, unsigned char *md, unsigned int *md_len)
 212 {
 213         HMAC_CTX c;
 214         static unsigned char m[EVP_MAX_MD_SIZE];
 215
 216         if (md == NULL)
 217                 md = m;
 218         HMAC_CTX_init(&c);
 219         if (!HMAC_Init(&c, key, key_len, evp_md))
 220                 goto err;
 221         if (!HMAC_Update(&c, d, n))
 222                 goto err;
 223         if (!HMAC_Final(&c, md, md_len))
 224                 goto err;
 225         HMAC_CTX_cleanup(&c);
 226         return md;
 227 err:
 228         HMAC_CTX_cleanup(&c);
 229         return NULL;
 230 }
 231
 232 void
 233 HMAC_CTX_set_flags(HMAC_CTX *ctx, unsigned long flags)
 234 {
 235         EVP_MD_CTX_set_flags(&ctx->i_ctx, flags);
 236         EVP_MD_CTX_set_flags(&ctx->o_ctx, flags);
 237         EVP_MD_CTX_set_flags(&ctx->md_ctx, flags);
 238 }