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/*
Unix SMB/CIFS implementation.
HMAC MD5 code for use in NTLMv2
Copyright (C) Luke Kenneth Casson Leighton 1996-2000
Copyright (C) Andrew Tridgell 1992-2000
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*/
/* taken direct from rfc2104 implementation and modified for suitable use
* for ntlmv2.
*/
#include "includes.h"
#include "lib/crypto/crypto.h"
/***********************************************************************
the rfc 2104 version of hmac_md5 initialisation.
***********************************************************************/
void hmac_md5_init_rfc2104(const uint8_t *key, int key_len, HMACMD5Context *ctx)
{
int i;
/* if key is longer than 64 bytes reset it to key=MD5(key) */
if (key_len > 64)
{
uint8_t tk[16];
struct MD5Context tctx;
MD5Init(&tctx);
MD5Update(&tctx, key, key_len);
MD5Final(tk, &tctx);
key = tk;
key_len = 16;
}
/* start out by storing key in pads */
ZERO_STRUCT(ctx->k_ipad);
ZERO_STRUCT(ctx->k_opad);
memcpy( ctx->k_ipad, key, key_len);
memcpy( ctx->k_opad, key, key_len);
/* XOR key with ipad and opad values */
for (i=0; i<64; i++)
{
ctx->k_ipad[i] ^= 0x36;
ctx->k_opad[i] ^= 0x5c;
}
MD5Init(&ctx->ctx);
MD5Update(&ctx->ctx, ctx->k_ipad, 64);
}
/***********************************************************************
the microsoft version of hmac_md5 initialisation.
***********************************************************************/
void hmac_md5_init_limK_to_64(const uint8_t *key, int key_len,
HMACMD5Context *ctx)
{
/* if key is longer than 64 bytes truncate it */
if (key_len > 64)
{
key_len = 64;
}
hmac_md5_init_rfc2104(key, key_len, ctx);
}
/***********************************************************************
update hmac_md5 "inner" buffer
***********************************************************************/
void hmac_md5_update(const uint8_t *text, int text_len, HMACMD5Context *ctx)
{
MD5Update(&ctx->ctx, text, text_len); /* then text of datagram */
}
/***********************************************************************
finish off hmac_md5 "inner" buffer and generate outer one.
***********************************************************************/
void hmac_md5_final(uint8_t *digest, HMACMD5Context *ctx)
{
struct MD5Context ctx_o;
MD5Final(digest, &ctx->ctx);
MD5Init(&ctx_o);
MD5Update(&ctx_o, ctx->k_opad, 64);
MD5Update(&ctx_o, digest, 16);
MD5Final(digest, &ctx_o);
}
/***********************************************************
single function to calculate an HMAC MD5 digest from data.
use the microsoft hmacmd5 init method because the key is 16 bytes.
************************************************************/
void hmac_md5(const uint8_t key[16], const uint8_t *data, int data_len, uint8_t *digest)
{
HMACMD5Context ctx;
hmac_md5_init_limK_to_64(key, 16, &ctx);
if (data_len != 0)
{
hmac_md5_update(data, data_len, &ctx);
}
hmac_md5_final(digest, &ctx);
}
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