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/*
* ntlm proxy support for OpenVPN
*
* Copyright (C) 2004 William Preston
*
* 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 (see the file COPYING included with this
* distribution); if not, write to the Free Software Foundation, Inc.,
* 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
#ifdef WIN32
#include "config-win32.h"
#else
#include "config.h"
#endif
#include "syshead.h"
#if NTLM
#include "common.h"
#include "buffer.h"
#include "misc.h"
#include "socket.h"
#include "fdmisc.h"
#include "proxy.h"
#include "ntlm.h"
#include "base64.h"
#include "crypto.h"
#include "memdbg.h"
static void
create_des_keys(const unsigned char *hash, unsigned char *key)
{
key[0] = hash[0];
key[1] = ((hash[0]&1)<<7)|(hash[1]>>1);
key[2] = ((hash[1]&3)<<6)|(hash[2]>>2);
key[3] = ((hash[2]&7)<<5)|(hash[3]>>3);
key[4] = ((hash[3]&15)<<4)|(hash[4]>>4);
key[5] = ((hash[4]&31)<<3)|(hash[5]>>5);
key[6] = ((hash[5]&63)<<2)|(hash[6]>>6);
key[7] = ((hash[6]&127)<<1);
des_set_odd_parity((des_cblock *)key);
}
static void
gen_md4_hash (const char* data, int data_len, char *result)
{
/* result is 16 byte md4 hash */
MD4_CTX c;
char md[16];
MD4_Init (&c);
MD4_Update (&c, data, data_len);
MD4_Final ((unsigned char *)md, &c);
memcpy (result, md, 16);
}
static int
unicodize (char *dst, const char *src)
{
/* not really unicode... */
int i = 0;
do
{
dst[i++] = *src;
dst[i++] = 0;
}
while (*src++);
return i;
}
const char *
ntlm_phase_1 (const struct http_proxy_info *p, struct gc_arena *gc)
{
struct buffer out = alloc_buf_gc (96, gc);
/* try a minimal NTLM handshake
*
* http://davenport.sourceforge.net/ntlm.html
*
* This message contains only the NTLMSSP signature,
* the NTLM message type,
* and the minimal set of flags (Negotiate NTLM and Negotiate OEM).
*
*/
buf_printf (&out, "%s", "TlRMTVNTUAABAAAAAgIAAA==");
return (BSTR (&out));
}
const char *
ntlm_phase_3 (const struct http_proxy_info *p, const char *phase_2, struct gc_arena *gc)
{
char pwbuf[sizeof (p->up.password) * 2]; /* for unicode password */
char buf2[128]; /* decoded reply from proxy */
char phase3[146];
char md4_hash[21];
char challenge[8], response[24];
int i, ret_val, buflen;
des_cblock key1, key2, key3;
des_key_schedule sched1, sched2, sched3;
/* try a minimal NTLM handshake
*
* http://davenport.sourceforge.net/ntlm.html
*
*/
ASSERT (strlen (p->up.username) > 0);
ASSERT (strlen (p->up.password) > 0);
/* fill 1st 16 bytes with md4 hash, disregard terminating null */
gen_md4_hash (pwbuf, unicodize (pwbuf, p->up.password) - 2, md4_hash);
/* pad to 21 bytes */
memset (md4_hash + 16, 0, 5);
ret_val = base64_decode( phase_2, (void *)buf2);
/* we can be sure that phase_2 is less than 128
* therefore buf2 needs to be (3/4 * 128) */
/* extract the challenge from bytes 24-31 */
for (i=0; i<8; i++)
{
challenge[i] = buf2[i+24];
}
create_des_keys ((unsigned char *)md4_hash, key1);
des_set_key_unchecked ((des_cblock *)key1, sched1);
des_ecb_encrypt ((des_cblock *)challenge, (des_cblock *)response, sched1, DES_ENCRYPT);
create_des_keys ((unsigned char *)&(md4_hash[7]), key2);
des_set_key_unchecked ((des_cblock *)key2, sched2);
des_ecb_encrypt ((des_cblock *)challenge, (des_cblock *)&(response[8]), sched2, DES_ENCRYPT);
create_des_keys ((unsigned char *)&(md4_hash[14]), key3);
des_set_key_unchecked ((des_cblock *)key3, sched3);
des_ecb_encrypt ((des_cblock *)challenge, (des_cblock *)&(response[16]), sched3, DES_ENCRYPT);
/* clear reply */
memset (phase3, 0, sizeof (phase3));
strcpy (phase3, "NTLMSSP\0");
phase3[8] = 3; /* type 3 */
buflen = 0x58 + strlen (p->up.username);
if (buflen > (int) sizeof (phase3))
buflen = sizeof (phase3);
phase3[0x10] = buflen; /* lm not used */
phase3[0x20] = buflen; /* default domain (i.e. proxy's domain) */
phase3[0x30] = buflen; /* no workstation name supplied */
phase3[0x38] = buflen; /* no session key */
phase3[0x14] = 24; /* ntlm response is 24 bytes long */
phase3[0x16] = phase3[0x14];
phase3[0x18] = 0x40; /* ntlm offset */
memcpy (&(phase3[0x40]), response, 24);
phase3[0x24] = strlen (p->up.username); /* username in ascii */
phase3[0x26] = phase3[0x24];
phase3[0x28] = 0x58;
strncpy (&(phase3[0x58]), p->up.username, sizeof (phase3) - 0x58);
phase3[0x3c] = 0x02; /* negotiate oem */
phase3[0x3d] = 0x02; /* negotiate ntlm */
return ((const char *)make_base64_string2 ((unsigned char *)phase3, buflen, gc));
}
#else
static void dummy(void) {}
#endif
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