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-rw-r--r--ntlm.c188
1 files changed, 188 insertions, 0 deletions
diff --git a/ntlm.c b/ntlm.c
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+++ b/ntlm.c
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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