/* -*- c-basic-offset: 8 -*- rdesktop: A Remote Desktop Protocol client. Protocol services - RDP encryption and licensing Copyright (C) Matthew Chapman 1999-2005 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. */ #include "rdesktop.h" //#include //#include //#include //#include //#include void * ssl_sha1_info_create(void); void ssl_sha1_info_delete(void * sha1_info); void ssl_sha1_clear(void * sha1_info); void ssl_sha1_transform(void * sha1_info, char * data, int len); void ssl_sha1_complete(void * sha1_info, char * data); void * ssl_md5_info_create(void); void ssl_md5_info_delete(void * md5_info); void * ssl_md5_info_create(void); void ssl_md5_info_delete(void * md5_info); void ssl_md5_clear(void * md5_info); void ssl_md5_transform(void * md5_info, char * data, int len); void ssl_md5_complete(void * md5_info, char * data); void * ssl_rc4_info_create(void); void ssl_rc4_info_delete(void * rc4_info); void ssl_rc4_set_key(void * rc4_info, char * key, int len); void ssl_rc4_crypt(void * rc4_info, char * in_data, char * out_data, int len); int ssl_mod_exp(char* out, int out_len, char* in, int in_len, char* mod, int mod_len, char* exp, int exp_len); extern char g_hostname[16]; extern int g_width; extern int g_height; extern unsigned int g_keylayout; extern int g_keyboard_type; extern int g_keyboard_subtype; extern int g_keyboard_functionkeys; extern BOOL g_encryption; extern BOOL g_licence_issued; extern BOOL g_use_rdp5; extern BOOL g_console_session; extern int g_server_depth; extern uint16 mcs_userid; extern VCHANNEL g_channels[]; extern unsigned int g_num_channels; static int rc4_key_len; static void * rc4_decrypt_key = 0; static void * rc4_encrypt_key = 0; //static RSA *server_public_key; static void * server_public_key; static uint8 sec_sign_key[16]; static uint8 sec_decrypt_key[16]; static uint8 sec_encrypt_key[16]; static uint8 sec_decrypt_update_key[16]; static uint8 sec_encrypt_update_key[16]; static uint8 sec_crypted_random[SEC_MODULUS_SIZE]; uint16 g_server_rdp_version = 0; /* These values must be available to reset state - Session Directory */ static int sec_encrypt_use_count = 0; static int sec_decrypt_use_count = 0; /* * I believe this is based on SSLv3 with the following differences: * MAC algorithm (5.2.3.1) uses only 32-bit length in place of seq_num/type/length fields * MAC algorithm uses SHA1 and MD5 for the two hash functions instead of one or other * key_block algorithm (6.2.2) uses 'X', 'YY', 'ZZZ' instead of 'A', 'BB', 'CCC' * key_block partitioning is different (16 bytes each: MAC secret, decrypt key, encrypt key) * encryption/decryption keys updated every 4096 packets * See http://wp.netscape.com/eng/ssl3/draft302.txt */ /* * 48-byte transformation used to generate master secret (6.1) and key material (6.2.2). * Both SHA1 and MD5 algorithms are used. */ void sec_hash_48(uint8 * out, uint8 * in, uint8 * salt1, uint8 * salt2, uint8 salt) { uint8 shasig[20]; uint8 pad[4]; void * sha; void * md5; int i; for (i = 0; i < 3; i++) { memset(pad, salt + i, i + 1); sha = ssl_sha1_info_create(); ssl_sha1_clear(sha); ssl_sha1_transform(sha, pad, i + 1); ssl_sha1_transform(sha, in, 48); ssl_sha1_transform(sha, salt1, 32); ssl_sha1_transform(sha, salt2, 32); ssl_sha1_complete(sha, shasig); ssl_sha1_info_delete(sha); md5 = ssl_md5_info_create(); ssl_md5_clear(md5); ssl_md5_transform(md5, in, 48); ssl_md5_transform(md5, shasig, 20); ssl_md5_complete(md5, out + i * 16); ssl_md5_info_delete(md5); } } /* * 16-byte transformation used to generate export keys (6.2.2). */ void sec_hash_16(uint8 * out, uint8 * in, uint8 * salt1, uint8 * salt2) { void * md5; md5 = ssl_md5_info_create(); ssl_md5_clear(md5); ssl_md5_transform(md5, in, 16); ssl_md5_transform(md5, salt1, 32); ssl_md5_transform(md5, salt2, 32); ssl_md5_complete(md5, out); ssl_md5_info_delete(md5); } /* Reduce key entropy from 64 to 40 bits */ static void sec_make_40bit(uint8 * key) { key[0] = 0xd1; key[1] = 0x26; key[2] = 0x9e; } /* Generate encryption keys given client and server randoms */ static void sec_generate_keys(uint8 * client_random, uint8 * server_random, int rc4_key_size) { uint8 pre_master_secret[48]; uint8 master_secret[48]; uint8 key_block[48]; /* Construct pre-master secret */ memcpy(pre_master_secret, client_random, 24); memcpy(pre_master_secret + 24, server_random, 24); /* Generate master secret and then key material */ sec_hash_48(master_secret, pre_master_secret, client_random, server_random, 'A'); sec_hash_48(key_block, master_secret, client_random, server_random, 'X'); /* First 16 bytes of key material is MAC secret */ memcpy(sec_sign_key, key_block, 16); /* Generate export keys from next two blocks of 16 bytes */ sec_hash_16(sec_decrypt_key, &key_block[16], client_random, server_random); sec_hash_16(sec_encrypt_key, &key_block[32], client_random, server_random); if (rc4_key_size == 1) { DEBUG(("40-bit encryption enabled\n")); sec_make_40bit(sec_sign_key); sec_make_40bit(sec_decrypt_key); sec_make_40bit(sec_encrypt_key); rc4_key_len = 8; } else { DEBUG(("rc_4_key_size == %d, 128-bit encryption enabled\n", rc4_key_size)); rc4_key_len = 16; } /* Save initial RC4 keys as update keys */ memcpy(sec_decrypt_update_key, sec_decrypt_key, 16); memcpy(sec_encrypt_update_key, sec_encrypt_key, 16); /* Initialise RC4 state arrays */ ssl_rc4_info_delete(rc4_decrypt_key); rc4_decrypt_key = ssl_rc4_info_create(); ssl_rc4_set_key(rc4_decrypt_key, sec_decrypt_key, rc4_key_len); ssl_rc4_info_delete(rc4_encrypt_key); rc4_encrypt_key = ssl_rc4_info_create(); ssl_rc4_set_key(rc4_encrypt_key, sec_encrypt_key, rc4_key_len); } static uint8 pad_54[40] = { 54, 54, 54, 54, 54, 54, 54, 54, 54, 54, 54, 54, 54, 54, 54, 54, 54, 54, 54, 54, 54, 54, 54, 54, 54, 54, 54, 54, 54, 54, 54, 54, 54, 54, 54, 54, 54, 54, 54, 54 }; static uint8 pad_92[48] = { 92, 92, 92, 92, 92, 92, 92, 92, 92, 92, 92, 92, 92, 92, 92, 92, 92, 92, 92, 92, 92, 92, 92, 92, 92, 92, 92, 92, 92, 92, 92, 92, 92, 92, 92, 92, 92, 92, 92, 92, 92, 92, 92, 92, 92, 92, 92, 92 }; /* Output a uint32 into a buffer (little-endian) */ void buf_out_uint32(uint8 * buffer, uint32 value) { buffer[0] = (value) & 0xff; buffer[1] = (value >> 8) & 0xff; buffer[2] = (value >> 16) & 0xff; buffer[3] = (value >> 24) & 0xff; } /* Generate a MAC hash (5.2.3.1), using a combination of SHA1 and MD5 */ void sec_sign(uint8 * signature, int siglen, uint8 * session_key, int keylen, uint8 * data, int datalen) { uint8 shasig[20]; uint8 md5sig[16]; uint8 lenhdr[4]; void * sha; void * md5; buf_out_uint32(lenhdr, datalen); sha = ssl_sha1_info_create(); ssl_sha1_clear(sha); ssl_sha1_transform(sha, session_key, keylen); ssl_sha1_transform(sha, pad_54, 40); ssl_sha1_transform(sha, lenhdr, 4); ssl_sha1_transform(sha, data, datalen); ssl_sha1_complete(sha, shasig); ssl_sha1_info_delete(sha); md5 = ssl_md5_info_create(); ssl_md5_clear(md5); ssl_md5_transform(md5, session_key, keylen); ssl_md5_transform(md5, pad_92, 48); ssl_md5_transform(md5, shasig, 20); ssl_md5_complete(md5, md5sig); ssl_md5_info_delete(md5); memcpy(signature, md5sig, siglen); } /* Update an encryption key */ static void sec_update(uint8 * key, uint8 * update_key) { uint8 shasig[20]; void * sha; void * md5; void * update; sha = ssl_sha1_info_create(); ssl_sha1_clear(sha); ssl_sha1_transform(sha, update_key, rc4_key_len); ssl_sha1_transform(sha, pad_54, 40); ssl_sha1_transform(sha, key, rc4_key_len); ssl_sha1_complete(sha, shasig); ssl_sha1_info_delete(sha); md5 = ssl_md5_info_create(); ssl_md5_clear(md5); ssl_md5_transform(md5, update_key, rc4_key_len); ssl_md5_transform(md5, pad_92, 48); ssl_md5_transform(md5, shasig, 20); ssl_md5_complete(md5, key); ssl_md5_info_delete(md5); update = ssl_rc4_info_create(); ssl_rc4_set_key(update, key, rc4_key_len); ssl_rc4_crypt(update, key, key, rc4_key_len); ssl_rc4_info_delete(update); if (rc4_key_len == 8) sec_make_40bit(key); } /* Encrypt data using RC4 */ static void sec_encrypt(uint8 * data, int length) { if (sec_encrypt_use_count == 4096) { sec_update(sec_encrypt_key, sec_encrypt_update_key); ssl_rc4_set_key(rc4_encrypt_key, sec_encrypt_key, rc4_key_len); sec_encrypt_use_count = 0; } ssl_rc4_crypt(rc4_encrypt_key, data, data, length); sec_encrypt_use_count++; } /* Decrypt data using RC4 */ void sec_decrypt(uint8 * data, int length) { if (sec_decrypt_use_count == 4096) { sec_update(sec_decrypt_key, sec_decrypt_update_key); ssl_rc4_set_key(rc4_decrypt_key, sec_decrypt_key, rc4_key_len); sec_decrypt_use_count = 0; } ssl_rc4_crypt(rc4_decrypt_key, data, data, length); sec_decrypt_use_count++; } /*static void reverse(uint8 * p, int len) { int i, j; uint8 temp; for (i = 0, j = len - 1; i < j; i++, j--) { temp = p[i]; p[i] = p[j]; p[j] = temp; } }*/ /* Perform an RSA public key encryption operation */ static void sec_rsa_encrypt(uint8 * out, uint8 * in, int len, uint8 * modulus, uint8 * exponent) { ssl_mod_exp(out, 64, in, 32, modulus, 64, exponent, 4); /* BN_CTX *ctx; BIGNUM mod, exp, x, y; uint8 inr[SEC_MODULUS_SIZE]; int outlen; reverse(modulus, SEC_MODULUS_SIZE); reverse(exponent, SEC_EXPONENT_SIZE); memcpy(inr, in, len); reverse(inr, len); ctx = BN_CTX_new(); BN_init(&mod); BN_init(&exp); BN_init(&x); BN_init(&y); BN_bin2bn(modulus, SEC_MODULUS_SIZE, &mod); BN_bin2bn(exponent, SEC_EXPONENT_SIZE, &exp); BN_bin2bn(inr, len, &x); BN_mod_exp(&y, &x, &exp, &mod, ctx); outlen = BN_bn2bin(&y, out); reverse(out, outlen); if (outlen < SEC_MODULUS_SIZE) memset(out + outlen, 0, SEC_MODULUS_SIZE - outlen); BN_free(&y); BN_clear_free(&x); BN_free(&exp); BN_free(&mod); BN_CTX_free(ctx);*/ } /* Initialise secure transport packet */ STREAM sec_init(uint32 flags, int maxlen) { int hdrlen; STREAM s; if (!g_licence_issued) hdrlen = (flags & SEC_ENCRYPT) ? 12 : 4; else hdrlen = (flags & SEC_ENCRYPT) ? 12 : 0; s = mcs_init(maxlen + hdrlen); s_push_layer(s, sec_hdr, hdrlen); return s; } /* Transmit secure transport packet over specified channel */ void sec_send_to_channel(STREAM s, uint32 flags, uint16 channel) { int datalen; s_pop_layer(s, sec_hdr); if (!g_licence_issued || (flags & SEC_ENCRYPT)) out_uint32_le(s, flags); if (flags & SEC_ENCRYPT) { flags &= ~SEC_ENCRYPT; datalen = s->end - s->p - 8; #ifdef WITH_DEBUG DEBUG(("Sending encrypted packet:\n")); hexdump(s->p + 8, datalen); #endif sec_sign(s->p, 8, sec_sign_key, rc4_key_len, s->p + 8, datalen); sec_encrypt(s->p + 8, datalen); } mcs_send_to_channel(s, channel); } /* Transmit secure transport packet */ void sec_send(STREAM s, uint32 flags) { sec_send_to_channel(s, flags, MCS_GLOBAL_CHANNEL); } /* Transfer the client random to the server */ static void sec_establish_key(void) { uint32 length = SEC_MODULUS_SIZE + SEC_PADDING_SIZE; uint32 flags = SEC_CLIENT_RANDOM; STREAM s; s = sec_init(flags, 76); out_uint32_le(s, length); out_uint8p(s, sec_crypted_random, SEC_MODULUS_SIZE); out_uint8s(s, SEC_PADDING_SIZE); s_mark_end(s); sec_send(s, flags); } /* Output connect initial data blob */ static void sec_out_mcs_data(STREAM s) { int hostlen = 2 * strlen(g_hostname); int length = 158 + 76 + 12 + 4; unsigned int i; if (g_num_channels > 0) length += g_num_channels * 12 + 8; if (hostlen > 30) hostlen = 30; /* Generic Conference Control (T.124) ConferenceCreateRequest */ out_uint16_be(s, 5); out_uint16_be(s, 0x14); out_uint8(s, 0x7c); out_uint16_be(s, 1); out_uint16_be(s, (length | 0x8000)); /* remaining length */ out_uint16_be(s, 8); /* length? */ out_uint16_be(s, 16); out_uint8(s, 0); out_uint16_le(s, 0xc001); out_uint8(s, 0); out_uint32_le(s, 0x61637544); /* OEM ID: "Duca", as in Ducati. */ out_uint16_be(s, ((length - 14) | 0x8000)); /* remaining length */ /* Client information */ out_uint16_le(s, SEC_TAG_CLI_INFO); out_uint16_le(s, 212); /* length */ out_uint16_le(s, g_use_rdp5 ? 4 : 1); /* RDP version. 1 == RDP4, 4 == RDP5. */ out_uint16_le(s, 8); out_uint16_le(s, g_width); out_uint16_le(s, g_height); out_uint16_le(s, 0xca01); out_uint16_le(s, 0xaa03); out_uint32_le(s, g_keylayout); out_uint32_le(s, 2600); /* Client build. We are now 2600 compatible :-) */ /* Unicode name of client, padded to 32 bytes */ rdp_out_unistr(s, g_hostname, hostlen); out_uint8s(s, 30 - hostlen); /* See http://msdn.microsoft.com/library/default.asp?url=/library/en-us/wceddk40/html/cxtsksupportingremotedesktopprotocol.asp */ out_uint32_le(s, g_keyboard_type); out_uint32_le(s, g_keyboard_subtype); out_uint32_le(s, g_keyboard_functionkeys); out_uint8s(s, 64); /* reserved? 4 + 12 doublewords */ out_uint16_le(s, 0xca01); /* colour depth? */ out_uint16_le(s, 1); out_uint32(s, 0); out_uint8(s, g_server_depth); out_uint16_le(s, 0x0700); out_uint8(s, 0); out_uint32_le(s, 1); out_uint8s(s, 64); /* End of client info */ out_uint16_le(s, SEC_TAG_CLI_4); out_uint16_le(s, 12); out_uint32_le(s, g_console_session ? 0xb : 9); out_uint32(s, 0); /* Client encryption settings */ out_uint16_le(s, SEC_TAG_CLI_CRYPT); out_uint16_le(s, 12); /* length */ out_uint32_le(s, g_encryption ? 0x3 : 0); /* encryption supported, 128-bit supported */ out_uint32(s, 0); /* Unknown */ DEBUG_RDP5(("g_num_channels is %d\n", g_num_channels)); if (g_num_channels > 0) { out_uint16_le(s, SEC_TAG_CLI_CHANNELS); out_uint16_le(s, g_num_channels * 12 + 8); /* length */ out_uint32_le(s, g_num_channels); /* number of virtual channels */ for (i = 0; i < g_num_channels; i++) { DEBUG_RDP5(("Requesting channel %s\n", g_channels[i].name)); out_uint8a(s, g_channels[i].name, 8); out_uint32_be(s, g_channels[i].flags); } } s_mark_end(s); } /* Parse a public key structure */ static BOOL sec_parse_public_key(STREAM s, uint8 ** modulus, uint8 ** exponent) { uint32 magic, modulus_len; in_uint32_le(s, magic); if (magic != SEC_RSA_MAGIC) { error("RSA magic 0x%x\n", magic); return False; } in_uint32_le(s, modulus_len); if (modulus_len != SEC_MODULUS_SIZE + SEC_PADDING_SIZE) { error("modulus len 0x%x\n", modulus_len); return False; } in_uint8s(s, 8); /* modulus_bits, unknown */ in_uint8p(s, *exponent, SEC_EXPONENT_SIZE); in_uint8p(s, *modulus, SEC_MODULUS_SIZE); in_uint8s(s, SEC_PADDING_SIZE); return s_check(s); } /* Parse a crypto information structure */ static BOOL sec_parse_crypt_info(STREAM s, uint32 * rc4_key_size, uint8 ** server_random, uint8 ** modulus, uint8 ** exponent) { uint32 crypt_level, random_len, rsa_info_len; uint32 /*cacert_len, cert_len,*/ flags; //X509 *cacert, *server_cert; uint16 tag, length; uint8 *next_tag, *end; in_uint32_le(s, *rc4_key_size); /* 1 = 40-bit, 2 = 128-bit */ in_uint32_le(s, crypt_level); /* 1 = low, 2 = medium, 3 = high */ if (crypt_level == 0) /* no encryption */ return False; in_uint32_le(s, random_len); in_uint32_le(s, rsa_info_len); if (random_len != SEC_RANDOM_SIZE) { error("random len %d, expected %d\n", random_len, SEC_RANDOM_SIZE); return False; } in_uint8p(s, *server_random, random_len); /* RSA info */ end = s->p + rsa_info_len; if (end > s->end) return False; in_uint32_le(s, flags); /* 1 = RDP4-style, 0x80000002 = X.509 */ if (flags & 1) { DEBUG_RDP5(("We're going for the RDP4-style encryption\n")); in_uint8s(s, 8); /* unknown */ while (s->p < end) { in_uint16_le(s, tag); in_uint16_le(s, length); next_tag = s->p + length; switch (tag) { case SEC_TAG_PUBKEY: if (!sec_parse_public_key(s, modulus, exponent)) return False; DEBUG_RDP5(("Got Public key, RDP4-style\n")); break; case SEC_TAG_KEYSIG: /* Is this a Microsoft key that we just got? */ /* Care factor: zero! */ /* Actually, it would probably be a good idea to check if the public key is signed with this key, and then store this key as a known key of the hostname. This would prevent some MITM-attacks. */ break; default: unimpl("crypt tag 0x%x\n", tag); } s->p = next_tag; } } else { #if 0 uint32 certcount; DEBUG_RDP5(("We're going for the RDP5-style encryption\n")); in_uint32_le(s, certcount); /* Number of certificates */ if (certcount < 2) { error("Server didn't send enough X509 certificates\n"); return False; } for (; certcount > 2; certcount--) { /* ignore all the certificates between the root and the signing CA */ uint32 ignorelen; X509 *ignorecert; DEBUG_RDP5(("Ignored certs left: %d\n", certcount)); in_uint32_le(s, ignorelen); DEBUG_RDP5(("Ignored Certificate length is %d\n", ignorelen)); ignorecert = d2i_X509(NULL, &(s->p), ignorelen); if (ignorecert == NULL) { /* XXX: error out? */ DEBUG_RDP5(("got a bad cert: this will probably screw up the rest of the communication\n")); } #ifdef WITH_DEBUG_RDP5 DEBUG_RDP5(("cert #%d (ignored):\n", certcount)); X509_print_fp(stdout, ignorecert); #endif } /* Do da funky X.509 stuffy "How did I find out about this? I looked up and saw a bright light and when I came to I had a scar on my forehead and knew about X.500" - Peter Gutman in a early version of http://www.cs.auckland.ac.nz/~pgut001/pubs/x509guide.txt */ in_uint32_le(s, cacert_len); DEBUG_RDP5(("CA Certificate length is %d\n", cacert_len)); cacert = d2i_X509(NULL, &(s->p), cacert_len); /* Note: We don't need to move s->p here - d2i_X509 is "kind" enough to do it for us */ if (NULL == cacert) { error("Couldn't load CA Certificate from server\n"); return False; } /* Currently, we don't use the CA Certificate. FIXME: *) Verify the server certificate (server_cert) with the CA certificate. *) Store the CA Certificate with the hostname of the server we are connecting to as key, and compare it when we connect the next time, in order to prevent MITM-attacks. */ X509_free(cacert); in_uint32_le(s, cert_len); DEBUG_RDP5(("Certificate length is %d\n", cert_len)); server_cert = d2i_X509(NULL, &(s->p), cert_len); if (NULL == server_cert) { error("Couldn't load Certificate from server\n"); return False; } in_uint8s(s, 16); /* Padding */ /* Note: Verifying the server certificate must be done here, before sec_parse_public_key since we'll have to apply serious violence to the key after this */ if (!sec_parse_x509_key(server_cert)) { DEBUG_RDP5(("Didn't parse X509 correctly\n")); X509_free(server_cert); return False; } X509_free(server_cert); return True; /* There's some garbage here we don't care about */ #endif } return s_check_end(s); } /* Process crypto information blob */ static void sec_process_crypt_info(STREAM s) { uint8 *server_random, *modulus, *exponent; uint8 client_random[SEC_RANDOM_SIZE]; uint32 rc4_key_size; uint8 inr[SEC_MODULUS_SIZE]; if (!sec_parse_crypt_info(s, &rc4_key_size, &server_random, &modulus, &exponent)) { DEBUG(("Failed to parse crypt info\n")); return; } DEBUG(("Generating client random\n")); /* Generate a client random, and hence determine encryption keys */ /* This is what the MS client do: */ memset(inr, 0, SEC_RANDOM_SIZE); /* *ARIGL!* Plaintext attack, anyone? I tried doing: generate_random(inr); ..but that generates connection errors now and then (yes, "now and then". Something like 0 to 3 attempts needed before a successful connection. Nice. Not! */ generate_random(client_random); if (NULL != server_public_key) { /* Which means we should use RDP5-style encryption */ #if 0 memcpy(inr + SEC_RANDOM_SIZE, client_random, SEC_RANDOM_SIZE); reverse(inr + SEC_RANDOM_SIZE, SEC_RANDOM_SIZE); RSA_public_encrypt(SEC_MODULUS_SIZE, inr, sec_crypted_random, server_public_key, RSA_NO_PADDING); reverse(sec_crypted_random, SEC_MODULUS_SIZE); RSA_free(server_public_key); server_public_key = NULL; #endif } else { /* RDP4-style encryption */ sec_rsa_encrypt(sec_crypted_random, client_random, SEC_RANDOM_SIZE, modulus, exponent); } sec_generate_keys(client_random, server_random, rc4_key_size); } /* Process SRV_INFO, find RDP version supported by server */ static void sec_process_srv_info(STREAM s) { in_uint16_le(s, g_server_rdp_version); DEBUG_RDP5(("Server RDP version is %d\n", g_server_rdp_version)); if (1 == g_server_rdp_version) { g_use_rdp5 = 0; g_server_depth = 8; } } /* Process connect response data blob */ void sec_process_mcs_data(STREAM s) { uint16 tag, length; uint8 *next_tag; uint8 len; in_uint8s(s, 21); /* header (T.124 ConferenceCreateResponse) */ in_uint8(s, len); if (len & 0x80) in_uint8(s, len); while (s->p < s->end) { in_uint16_le(s, tag); in_uint16_le(s, length); if (length <= 4) return; next_tag = s->p + length - 4; switch (tag) { case SEC_TAG_SRV_INFO: sec_process_srv_info(s); break; case SEC_TAG_SRV_CRYPT: sec_process_crypt_info(s); break; case SEC_TAG_SRV_CHANNELS: /* FIXME: We should parse this information and use it to map RDP5 channels to MCS channels */ break; default: unimpl("response tag 0x%x\n", tag); } s->p = next_tag; } } /* Receive secure transport packet */ STREAM sec_recv(uint8 * rdpver) { uint32 sec_flags; uint16 channel; STREAM s; while ((s = mcs_recv(&channel, rdpver)) != NULL) { if (rdpver != NULL) { if (*rdpver != 3) { if (*rdpver & 0x80) { in_uint8s(s, 8); /* signature */ sec_decrypt(s->p, s->end - s->p); } return s; } } if (g_encryption || !g_licence_issued) { in_uint32_le(s, sec_flags); if (sec_flags & SEC_ENCRYPT) { in_uint8s(s, 8); /* signature */ sec_decrypt(s->p, s->end - s->p); } if (sec_flags & SEC_LICENCE_NEG) { licence_process(s); continue; } if (sec_flags & 0x0400) /* SEC_REDIRECT_ENCRYPT */ { uint8 swapbyte; in_uint8s(s, 8); /* signature */ sec_decrypt(s->p, s->end - s->p); /* Check for a redirect packet, starts with 00 04 */ if (s->p[0] == 0 && s->p[1] == 4) { /* for some reason the PDU and the length seem to be swapped. This isn't good, but we're going to do a byte for byte swap. So the first foure value appear as: 00 04 XX YY, where XX YY is the little endian length. We're going to use 04 00 as the PDU type, so after our swap this will look like: XX YY 04 00 */ swapbyte = s->p[0]; s->p[0] = s->p[2]; s->p[2] = swapbyte; swapbyte = s->p[1]; s->p[1] = s->p[3]; s->p[3] = swapbyte; swapbyte = s->p[2]; s->p[2] = s->p[3]; s->p[3] = swapbyte; } #ifdef WITH_DEBUG /* warning! this debug statement will show passwords in the clear! */ hexdump(s->p, s->end - s->p); #endif } } if (channel != MCS_GLOBAL_CHANNEL) { channel_process(s, channel); *rdpver = 0xff; return s; } return s; } return NULL; } /* Establish a secure connection */ BOOL sec_connect(char *server, char *username) { struct stream mcs_data; /* We exchange some RDP data during the MCS-Connect */ mcs_data.size = 512; mcs_data.p = mcs_data.data = (uint8 *) xmalloc(mcs_data.size); sec_out_mcs_data(&mcs_data); if (!mcs_connect(server, &mcs_data, username)) return False; /* sec_process_mcs_data(&mcs_data); */ if (g_encryption) sec_establish_key(); xfree(mcs_data.data); return True; } /* Establish a secure connection */ BOOL sec_reconnect(char *server) { struct stream mcs_data; /* We exchange some RDP data during the MCS-Connect */ mcs_data.size = 512; mcs_data.p = mcs_data.data = (uint8 *) xmalloc(mcs_data.size); sec_out_mcs_data(&mcs_data); if (!mcs_reconnect(server, &mcs_data)) return False; /* sec_process_mcs_data(&mcs_data); */ if (g_encryption) sec_establish_key(); xfree(mcs_data.data); return True; } /* Disconnect a connection */ void sec_disconnect(void) { mcs_disconnect(); } /* reset the state of the sec layer */ void sec_reset_state(void) { g_server_rdp_version = 0; sec_encrypt_use_count = 0; sec_decrypt_use_count = 0; mcs_reset_state(); }