/*
* ntlm proxy support for OpenVPN
*
* Copyright (C) 2004 William Preston
*
* *NTLMv2 support and domain name parsing by Miroslav Zajic, Nextsoft s.r.o.*
*
* 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.,
* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
*/
#ifdef HAVE_CONFIG_H
#include "config.h"
#elif defined(_MSC_VER)
#include "config-msvc.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"
/* 64bit datatype macros */
#ifdef _MSC_VER
/* MS compilers */
#define UINTEGER64 __int64
#define UINT64(c) c ## Ui64
#else
/* Non MS compilers */
#define UINTEGER64 unsigned long long
#define UINT64(c) c ## LL
#endif
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);
key_des_fixup(key, 8, 1);
}
static void
gen_md4_hash(const char *data, int data_len, char *result)
{
/* result is 16 byte md4 hash */
const md_kt_t *md4_kt = md_kt_get("MD4");
char md[MD4_DIGEST_LENGTH];
md_full(md4_kt, data, data_len, md);
memcpy(result, md, MD4_DIGEST_LENGTH);
}
static void
gen_hmac_md5(const char *data, int data_len, const char *key, int key_len,char *result)
{
const md_kt_t *md5_kt = md_kt_get("MD5");
hmac_ctx_t hmac_ctx;
CLEAR(hmac_ctx);
hmac_ctx_init(&hmac_ctx, key, key_len, md5_kt);
hmac_ctx_update(&hmac_ctx, (const unsigned char *)data, data_len);
hmac_ctx_final(&hmac_ctx, (unsigned char *)result);
hmac_ctx_cleanup(&hmac_ctx);
}
static void
gen_timestamp(unsigned char *timestamp)
{
/* Copies 8 bytes long timestamp into "timestamp" buffer.
* Timestamp is Little-endian, 64-bit signed value representing the number of tenths of a microsecond since January 1, 1601.
*/
UINTEGER64 timestamp_ull;
timestamp_ull = openvpn_time(NULL);
timestamp_ull = (timestamp_ull + UINT64(11644473600)) * UINT64(10000000);
/* store little endian value */
timestamp[0] = timestamp_ull & UINT64(0xFF);
timestamp[1] = (timestamp_ull >> 8) & UINT64(0xFF);
timestamp[2] = (timestamp_ull >> 16) & UINT64(0xFF);
timestamp[3] = (timestamp_ull >> 24) & UINT64(0xFF);
timestamp[4] = (timestamp_ull >> 32) & UINT64(0xFF);
timestamp[5] = (timestamp_ull >> 40) & UINT64(0xFF);
timestamp[6] = (timestamp_ull >> 48) & UINT64(0xFF);
timestamp[7] = (timestamp_ull >> 56) & UINT64(0xFF);
}
static void
gen_nonce(unsigned char *nonce)
{
/* Generates 8 random bytes to be used as client nonce */
int i;
for (i = 0; i<8; i++)
{
nonce[i] = (unsigned char)get_random();
}
}
void
my_strupr(unsigned char *str)
{
/* converts string to uppercase in place */
while (*str)
{
*str = toupper(*str);
str++;
}
}
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;
}
static void
add_security_buffer(int sb_offset, void *data, int length, unsigned char *msg_buf, int *msg_bufpos)
{
/* Adds security buffer data to a message and sets security buffer's offset and length */
msg_buf[sb_offset] = (unsigned char)length;
msg_buf[sb_offset + 2] = msg_buf[sb_offset];
msg_buf[sb_offset + 4] = (unsigned char)(*msg_bufpos & 0xff);
msg_buf[sb_offset + 5] = (unsigned char)((*msg_bufpos >> 8) & 0xff);
memcpy(&msg_buf[*msg_bufpos], data, msg_buf[sb_offset]);
*msg_bufpos += length;
}
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)
{
/* NTLM handshake
*
* http://davenport.sourceforge.net/ntlm.html
*
*/
char pwbuf[sizeof(p->up.password) * 2]; /* for unicode password */
char buf2[128]; /* decoded reply from proxy */
unsigned char phase3[464];
char md4_hash[MD4_DIGEST_LENGTH+5];
char challenge[8], ntlm_response[24];
int i, ret_val;
char ntlmv2_response[144];
char userdomain_u[256]; /* for uppercase unicode username and domain */
char userdomain[128]; /* the same as previous but ascii */
char ntlmv2_hash[MD5_DIGEST_LENGTH];
char ntlmv2_hmacmd5[16];
char *ntlmv2_blob = ntlmv2_response + 16; /* inside ntlmv2_response, length: 128 */
int ntlmv2_blob_size = 0;
int phase3_bufpos = 0x40; /* offset to next security buffer data to be added */
size_t len;
char domain[128];
char username[128];
char *separator;
bool ntlmv2_enabled = (p->auth_method == HTTP_AUTH_NTLM2);
CLEAR(buf2);
ASSERT(strlen(p->up.username) > 0);
ASSERT(strlen(p->up.password) > 0);
/* username parsing */
separator = strchr(p->up.username, '\\');
if (separator == NULL)
{
strncpy(username, p->up.username, sizeof(username)-1);
username[sizeof(username)-1] = 0;
domain[0] = 0;
}
else
{
strncpy(username, separator+1, sizeof(username)-1);
username[sizeof(username)-1] = 0;
len = separator - p->up.username;
if (len > sizeof(domain) - 1)
{
len = sizeof(domain) - 1;
}
strncpy(domain, p->up.username, len);
domain[len] = 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 + MD4_DIGEST_LENGTH, 0, 5);
ret_val = openvpn_base64_decode( phase_2, (void *)buf2, -1);
if (ret_val < 0)
{
return NULL;
}
/* 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];
}
if (ntlmv2_enabled) /* Generate NTLMv2 response */
{
int tib_len;
/* NTLMv2 hash */
my_strupr((unsigned char *)strcpy(userdomain, username));
if (strlen(username) + strlen(domain) < sizeof(userdomain))
{
strcat(userdomain, domain);
}
else
{
msg(M_INFO, "Warning: Username or domain too long");
}
unicodize(userdomain_u, userdomain);
gen_hmac_md5(userdomain_u, 2 * strlen(userdomain), md4_hash, MD5_DIGEST_LENGTH, ntlmv2_hash);
/* NTLMv2 Blob */
memset(ntlmv2_blob, 0, 128); /* Clear blob buffer */
ntlmv2_blob[0x00] = 1; /* Signature */
ntlmv2_blob[0x01] = 1; /* Signature */
ntlmv2_blob[0x04] = 0; /* Reserved */
gen_timestamp((unsigned char *)&ntlmv2_blob[0x08]); /* 64-bit Timestamp */
gen_nonce((unsigned char *)&ntlmv2_blob[0x10]); /* 64-bit Client Nonce */
ntlmv2_blob[0x18] = 0; /* Unknown, zero should work */
/* Add target information block to the blob */
if (( *((long *)&buf2[0x14]) & 0x00800000) == 0x00800000) /* Check for Target Information block */
{
tib_len = buf2[0x28]; /* Get Target Information block size */
if (tib_len > 96)
{
tib_len = 96;
}
{
char *tib_ptr = buf2 + buf2[0x2c]; /* Get Target Information block pointer */
memcpy(&ntlmv2_blob[0x1c], tib_ptr, tib_len); /* Copy Target Information block into the blob */
}
}
else
{
tib_len = 0;
}
ntlmv2_blob[0x1c + tib_len] = 0; /* Unknown, zero works */
/* Get blob length */
ntlmv2_blob_size = 0x20 + tib_len;
/* Add challenge from message 2 */
memcpy(&ntlmv2_response[8], challenge, 8);
/* hmac-md5 */
gen_hmac_md5(&ntlmv2_response[8], ntlmv2_blob_size + 8, ntlmv2_hash, MD5_DIGEST_LENGTH, ntlmv2_hmacmd5);
/* Add hmac-md5 result to the blob */
memcpy(ntlmv2_response, ntlmv2_hmacmd5, MD5_DIGEST_LENGTH); /* Note: This overwrites challenge previously written at ntlmv2_response[8..15] */
}
else /* Generate NTLM response */
{
unsigned char key1[DES_KEY_LENGTH], key2[DES_KEY_LENGTH], key3[DES_KEY_LENGTH];
create_des_keys((unsigned char *)md4_hash, key1);
cipher_des_encrypt_ecb(key1, challenge, ntlm_response);
create_des_keys((unsigned char *)&(md4_hash[DES_KEY_LENGTH-1]), key2);
cipher_des_encrypt_ecb(key2, challenge, &ntlm_response[DES_KEY_LENGTH]);
create_des_keys((unsigned char *)&(md4_hash[2*(DES_KEY_LENGTH-1)]), key3);
cipher_des_encrypt_ecb(key3, challenge, &ntlm_response[DES_KEY_LENGTH*2]);
}
memset(phase3, 0, sizeof(phase3)); /* clear reply */
strcpy((char *)phase3, "NTLMSSP\0"); /* signature */
phase3[8] = 3; /* type 3 */
if (ntlmv2_enabled) /* NTLMv2 response */
{
add_security_buffer(0x14, ntlmv2_response, ntlmv2_blob_size + 16, phase3, &phase3_bufpos);
}
else /* NTLM response */
{
add_security_buffer(0x14, ntlm_response, 24, phase3, &phase3_bufpos);
}
/* username in ascii */
add_security_buffer(0x24, username, strlen(username), phase3, &phase3_bufpos);
/* Set domain. If <domain> is empty, default domain will be used (i.e. proxy's domain) */
add_security_buffer(0x1c, domain, strlen(domain), phase3, &phase3_bufpos);
/* other security buffers will be empty */
phase3[0x10] = phase3_bufpos; /* lm not used */
phase3[0x30] = phase3_bufpos; /* no workstation name supplied */
phase3[0x38] = phase3_bufpos; /* no session key */
/* flags */
phase3[0x3c] = 0x02; /* negotiate oem */
phase3[0x3d] = 0x02; /* negotiate ntlm */
return ((const char *)make_base64_string2((unsigned char *)phase3, phase3_bufpos, gc));
}
#else /* if NTLM */
static void
dummy(void)
{
}
#endif /* if NTLM */