dlls/secur32/hmac_md5.c

   1 /*
   2  * Copyright 2006 Kai Blin
   3  *
   4  * This library is free software; you can redistribute it and/or
   5  * modify it under the terms of the GNU Lesser General Public
   6  * License as published by the Free Software Foundation; either
   7  * version 2.1 of the License, or (at your option) any later version.
   8  *
   9  * This library is distributed in the hope that it will be useful,
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  12  * Lesser General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU Lesser General Public
  15  * License along with this library; if not, write to the Free Software
  16  * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA
  17  *
  18  * This file implements RFC 2104 (HMAC) for the MD5 provider.
  19  * It is needed for NTLMv2 signing and sealing.
  20  */
  21
  22 #include "hmac_md5.h"
  23
  24 void HMACMD5Init(HMAC_MD5_CTX *ctx, const unsigned char *key, unsigned int key_len)
  25 {
  26     int i;
  27     unsigned char inner_padding[64];
  28     unsigned char temp_key[16];
  29
  30     if(key_len > 64)
  31     {
  32         MD5_CTX temp_ctx;
  33
  34         MD5Init(&temp_ctx);
  35         MD5Update(&temp_ctx, key, key_len);
  36         MD5Final(&temp_ctx);
  37         memcpy(temp_key, temp_ctx.digest, 16);
  38
  39         key = temp_key;
  40         key_len = 16;
  41     }
  42
  43     memset(inner_padding, 0, 64);
  44     memset(ctx->outer_padding, 0, 64);
  45     memcpy(inner_padding, key, key_len);
  46     memcpy(ctx->outer_padding, key, key_len);
  47
  48     for(i = 0; i < 64; ++i)
  49     {
  50         inner_padding[i] ^= 0x36;
  51         ctx->outer_padding[i] ^= 0x5c;
  52     }
  53
  54     MD5Init(&(ctx->ctx));
  55     MD5Update(&(ctx->ctx), inner_padding, 64);
  56 }
  57
  58 void HMACMD5Update(HMAC_MD5_CTX *ctx, const unsigned char *data, unsigned int data_len)
  59 {
  60     MD5Update(&(ctx->ctx), data, data_len);
  61 }
  62
  63 void HMACMD5Final(HMAC_MD5_CTX *ctx, unsigned char *digest)
  64 {
  65     MD5_CTX outer_ctx;
  66     unsigned char inner_digest[16];
  67
  68     MD5Final(&(ctx->ctx));
  69     memcpy(inner_digest, ctx->ctx.digest, 16);
  70
  71     MD5Init(&outer_ctx);
  72     MD5Update(&outer_ctx, ctx->outer_padding, 64);
  73     MD5Update(&outer_ctx, inner_digest, 16);
  74     MD5Final(&outer_ctx);
  75
  76     memcpy(digest, outer_ctx.digest, 16);
  77 }