/* * 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 uint8_t *data, int data_len, uint8_t *result) { /* result is 16 byte md4 hash */ const md_kt_t *md4_kt = md_kt_get("MD4"); uint8_t md[MD4_DIGEST_LENGTH]; md_full(md4_kt, data, data_len, md); memcpy(result, md, MD4_DIGEST_LENGTH); } static void gen_hmac_md5(const uint8_t *data, int data_len, const uint8_t *key, int key_len, uint8_t *result) { const md_kt_t *md5_kt = md_kt_get("MD5"); hmac_ctx_t *hmac_ctx = hmac_ctx_new(); hmac_ctx_init(hmac_ctx, key, key_len, md5_kt); hmac_ctx_update(hmac_ctx, data, data_len); hmac_ctx_final(hmac_ctx, result); hmac_ctx_cleanup(hmac_ctx); hmac_ctx_free(hmac_ctx); } static void gen_timestamp(uint8_t *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(); } } static void my_strupr(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 */ uint8_t buf2[128]; /* decoded reply from proxy */ uint8_t phase3[464]; uint8_t md4_hash[MD4_DIGEST_LENGTH + 5]; uint8_t challenge[8], ntlm_response[24]; int i, ret_val; uint8_t ntlmv2_response[144]; char userdomain_u[256]; /* for uppercase unicode username and domain */ char userdomain[128]; /* the same as previous but ascii */ uint8_t ntlmv2_hash[MD5_DIGEST_LENGTH]; uint8_t ntlmv2_hmacmd5[16]; uint8_t *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 */ int unicode_len = unicodize(pwbuf, p->up.password) - 2; gen_md4_hash((uint8_t *)pwbuf, unicode_len, md4_hash); /* pad to 21 bytes */ memset(md4_hash + MD4_DIGEST_LENGTH, 0, 5); ret_val = openvpn_base64_decode(phase_2, 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 */ strcpy(userdomain, username); my_strupr(userdomain); 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((uint8_t *)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(&ntlmv2_blob[0x08]); /* 64-bit Timestamp */ gen_nonce(&ntlmv2_blob[0x10]); /* 64-bit Client Nonce */ ntlmv2_blob[0x18] = 0; /* Unknown, zero should work */ /* Add target information block to the blob */ /* Check for Target Information block */ /* The NTLM spec instructs to interpret these 4 consecutive bytes as a * 32bit long integer. However, no endianness is specified. * The code here and that found in other NTLM implementations point * towards the assumption that the byte order on the wire has to * match the order on the sending and receiving hosts. Probably NTLM has * been thought to be always running on x86_64/i386 machine thus * implying Little-Endian everywhere. * * This said, in case of future changes, we should keep in mind that the * byte order on the wire for the NTLM header is LE. */ const size_t hoff = 0x14; unsigned long flags = buf2[hoff] | (buf2[hoff + 1] << 8) | (buf2[hoff + 2] << 16) | (buf2[hoff + 3] << 24); if ((flags & 0x00800000) == 0x00800000) { tib_len = buf2[0x28]; /* Get Target Information block size */ if (tib_len > 96) { tib_len = 96; } { uint8_t *tib_ptr; uint8_t tib_pos = buf2[0x2c]; if (tib_pos + tib_len > sizeof(buf2)) { return NULL; } /* Get Target Information block pointer */ tib_ptr = buf2 + tib_pos; /* Copy Target Information block into the blob */ memcpy(&ntlmv2_blob[0x1c], tib_ptr, tib_len); } } else { tib_len = 0; } /* Unknown, zero works */ ntlmv2_blob[0x1c + tib_len] = 0; /* 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. * Note: This overwrites challenge previously written at * ntlmv2_response[8..15] */ memcpy(ntlmv2_response, ntlmv2_hmacmd5, MD5_DIGEST_LENGTH); } else /* Generate NTLM response */ { unsigned char key1[DES_KEY_LENGTH], key2[DES_KEY_LENGTH]; unsigned char key3[DES_KEY_LENGTH]; create_des_keys(md4_hash, key1); cipher_des_encrypt_ecb(key1, challenge, ntlm_response); create_des_keys(&md4_hash[DES_KEY_LENGTH - 1], key2); cipher_des_encrypt_ecb(key2, challenge, &ntlm_response[DES_KEY_LENGTH]); create_des_keys(&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 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 */