source/lib/hmacmd5.c

   1 /*
   2    Unix SMB/Netbios implementation.
   3    Version 1.9.
   4    Interface header: Scheduler service
   5    Copyright (C) Luke Kenneth Casson Leighton 1996-2000
   6    Copyright (C) Andrew Tridgell 1992-2000
   7
   8    This program is free software; you can redistribute it and/or modify
   9    it under the terms of the GNU General Public License as published by
  10    the Free Software Foundation; either version 2 of the License, or
  11    (at your option) any later version.
  12
  13    This program is distributed in the hope that it will be useful,
  14    but WITHOUT ANY WARRANTY; without even the implied warranty of
  15    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16    GNU General Public License for more details.
  17
  18    You should have received a copy of the GNU General Public License
  19    along with this program; if not, write to the Free Software
  20    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  21 */
  22
  23 /* taken direct from rfc2104 implementation and modified for suitable use
  24  * for ntlmv2.
  25  */
  26
  27 #include "includes.h"
  28
  29 /***********************************************************************
  30  the rfc 2104 version of hmac_md5 initialisation.
  31 ***********************************************************************/
  32 void hmac_md5_init_rfc2104(uchar*  key, int key_len, HMACMD5Context *ctx)
  33 {
  34         int i;
  35
  36         /* if key is longer than 64 bytes reset it to key=MD5(key) */
  37         if (key_len > 64)
  38         {
  39                 uchar tk[16];
  40                 struct MD5Context tctx;
  41
  42                 MD5Init(&tctx);
  43                 MD5Update(&tctx, key, key_len);
  44                 MD5Final(tk, &tctx);
  45
  46                 key = tk;
  47                 key_len = 16;
  48         }
  49
  50         /* start out by storing key in pads */
  51         bzero( ctx->k_ipad, sizeof ctx->k_ipad);
  52         bzero( ctx->k_opad, sizeof ctx->k_opad);
  53         bcopy( key, ctx->k_ipad, key_len);
  54         bcopy( key, ctx->k_opad, key_len);
  55
  56         /* XOR key with ipad and opad values */
  57         for (i=0; i<64; i++)
  58         {
  59                 ctx->k_ipad[i] ^= 0x36;
  60                 ctx->k_opad[i] ^= 0x5c;
  61         }
  62
  63         MD5Init(&ctx->ctx);
  64         MD5Update(&ctx->ctx, ctx->k_ipad, 64);
  65 }
  66
  67 /***********************************************************************
  68  the microsoft version of hmac_md5 initialisation.
  69 ***********************************************************************/
  70 void hmac_md5_init_limK_to_64(const uchar* key, int key_len,
  71                         HMACMD5Context *ctx)
  72 {
  73         int i;
  74
  75         /* if key is longer than 64 bytes truncate it */
  76         if (key_len > 64)
  77         {
  78                 key_len = 64;
  79         }
  80
  81         /* start out by storing key in pads */
  82         bzero( ctx->k_ipad, sizeof ctx->k_ipad);
  83         bzero( ctx->k_opad, sizeof ctx->k_opad);
  84         bcopy( key, ctx->k_ipad, key_len);
  85         bcopy( key, ctx->k_opad, key_len);
  86
  87         /* XOR key with ipad and opad values */
  88         for (i=0; i<64; i++)
  89         {
  90                 ctx->k_ipad[i] ^= 0x36;
  91                 ctx->k_opad[i] ^= 0x5c;
  92         }
  93
  94         MD5Init(&ctx->ctx);
  95         MD5Update(&ctx->ctx, ctx->k_ipad, 64);
  96 }
  97
  98 /***********************************************************************
  99  update hmac_md5 "inner" buffer
 100 ***********************************************************************/
 101 void hmac_md5_update(const uchar* text, int text_len, HMACMD5Context *ctx)
 102 {
 103         MD5Update(&ctx->ctx, text, text_len); /* then text of datagram */
 104 }
 105
 106 /***********************************************************************
 107  finish off hmac_md5 "inner" buffer and generate outer one.
 108 ***********************************************************************/
 109 void hmac_md5_final(uchar *digest, HMACMD5Context *ctx)
 110
 111 {
 112         struct MD5Context ctx_o;
 113
 114         MD5Final(digest, &ctx->ctx);
 115
 116         MD5Init(&ctx_o);
 117         MD5Update(&ctx_o, ctx->k_opad, 64);
 118         MD5Update(&ctx_o, digest, 16);
 119         MD5Final(digest, &ctx_o);
 120 }
 121
 122 /***********************************************************
 123  single function to calculate an HMAC MD5 digest from data.
 124  use the microsoft hmacmd5 init method because the key is 16 bytes.
 125 ************************************************************/
 126 void hmac_md5( uchar key[16], uchar* data, int data_len, uchar* digest)
 127 {
 128         HMACMD5Context ctx;
 129         hmac_md5_init_limK_to_64(key, 16, &ctx);
 130         if (data_len != 0)
 131         {
 132                 hmac_md5_update(data, data_len, &ctx);
 133         }
 134         hmac_md5_final(digest, &ctx);
 135 }
 136