/* -*- c-basic-offset: 8 -*- rdesktop: A Remote Desktop Protocol client. Protocol services - RDP encryption and licensing Copyright (C) Matthew Chapman 1999-2008 Copyright 2005-2011 Peter Astrand for Cendio AB 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 3 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, see . */ #include "precomp.h" void * rdssl_sha1_info_create(void); void rdssl_sha1_info_delete(void * sha1_info); void rdssl_sha1_clear(void * sha1_info); void rdssl_sha1_transform(void * sha1_info, char * data, int len); void rdssl_sha1_complete(void * sha1_info, char * data); void * rdssl_md5_info_create(void); void rdssl_md5_info_delete(void * md5_info); void * rdssl_md5_info_create(void); void rdssl_md5_info_delete(void * md5_info); void rdssl_md5_clear(void * md5_info); void rdssl_md5_transform(void * md5_info, char * data, int len); void rdssl_md5_complete(void * md5_info, char * data); void * rdssl_rc4_info_create(void); void rdssl_rc4_info_delete(void * rc4_info); void rdssl_rc4_set_key(void * rc4_info, char * key, int len); void rdssl_rc4_crypt(void * rc4_info, char * in_data, char * out_data, int len); int rdssl_mod_exp(char* out, int out_len, char* in, int in_len, char* mod, int mod_len, char* exp, int exp_len); int rdssl_sign_ok(char* e_data, int e_len, char* n_data, int n_len, char* sign_data, int sign_len, char* sign_data2, int sign_len2, char* testkey); PCCERT_CONTEXT rdssl_cert_read(uint8 * data, uint32 len); void rdssl_cert_free(PCCERT_CONTEXT context); uint8 * rdssl_cert_to_rkey(PCCERT_CONTEXT cert, uint32 * key_len); RD_BOOL rdssl_certs_ok(PCCERT_CONTEXT server_cert, PCCERT_CONTEXT cacert); int rdssl_rkey_get_exp_mod(uint8 * rkey, uint8 * exponent, uint32 max_exp_len, uint8 * modulus, uint32 max_mod_len); void rdssl_rkey_free(uint8 * rkey); 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 RD_BOOL g_encryption; extern RD_BOOL g_licence_issued; extern RD_BOOL g_licence_error_result; extern RDP_VERSION g_rdp_version; extern RD_BOOL g_console_session; extern uint32 g_redirect_session_id; extern int g_server_depth; extern VCHANNEL g_channels[]; extern unsigned int g_num_channels; extern uint8 g_client_random[SEC_RANDOM_SIZE]; static int g_rc4_key_len; static void * g_rc4_decrypt_key; static void * g_rc4_encrypt_key; static uint32 g_server_public_key_len; static uint8 g_sec_sign_key[16]; static uint8 g_sec_decrypt_key[16]; static uint8 g_sec_encrypt_key[16]; static uint8 g_sec_decrypt_update_key[16]; static uint8 g_sec_encrypt_update_key[16]; static uint8 g_sec_crypted_random[SEC_MAX_MODULUS_SIZE]; uint16 g_server_rdp_version = 0; /* These values must be available to reset state - Session Directory */ static int g_sec_encrypt_use_count = 0; static int g_sec_decrypt_use_count = 0; #define SEC_MODULUS_SIZE 64 static uint8 g_testkey[176] = { 0x01, 0x00, 0x00, 0x00, 0x01, 0x00, 0x00, 0x00, 0x01, 0x00, 0x00, 0x00, 0x06, 0x00, 0x5c, 0x00, 0x52, 0x53, 0x41, 0x31, 0x48, 0x00, 0x00, 0x00, 0x00, 0x02, 0x00, 0x00, 0x3f, 0x00, 0x00, 0x00, 0x01, 0x00, 0x01, 0x00, 0x79, 0x6f, 0xb4, 0xdf, 0xa6, 0x95, 0xb9, 0xa9, 0x61, 0xe3, 0xc4, 0x5e, 0xff, 0x6b, 0xd8, 0x81, 0x8a, 0x12, 0x4a, 0x93, 0x42, 0x97, 0x18, 0x93, 0xac, 0xd1, 0x3a, 0x38, 0x3c, 0x68, 0x50, 0x19, 0x31, 0xb6, 0x84, 0x51, 0x79, 0xfb, 0x1c, 0xe7, 0xe3, 0x99, 0x20, 0xc7, 0x84, 0xdf, 0xd1, 0xaa, 0xb5, 0x15, 0xef, 0x47, 0x7e, 0xfc, 0x88, 0xeb, 0x29, 0xc3, 0x27, 0x5a, 0x35, 0xf8, 0xfd, 0xaa, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x08, 0x00, 0x48, 0x00, 0x32, 0x3b, 0xde, 0x6f, 0x18, 0x97, 0x1e, 0xc3, 0x6b, 0x2b, 0x2d, 0xe4, 0xfc, 0x2d, 0xa2, 0x8e, 0x32, 0x3c, 0xf3, 0x1b, 0x24, 0x90, 0x57, 0x4d, 0x8e, 0xe4, 0x69, 0xfc, 0x16, 0x8d, 0x41, 0x92, 0x78, 0xc7, 0x9c, 0xb4, 0x26, 0xff, 0xe8, 0x3e, 0xa1, 0x8a, 0xf5, 0x57, 0xc0, 0x7f, 0x3e, 0x21, 0x17, 0x32, 0x30, 0x6f, 0x79, 0xe1, 0x36, 0xcd, 0xb6, 0x8e, 0xbe, 0x57, 0x57, 0xd2, 0xa9, 0x36 }; /* * 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 = rdssl_sha1_info_create(); rdssl_sha1_clear(sha); rdssl_sha1_transform(sha, (char *)pad, i + 1); rdssl_sha1_transform(sha, (char *)in, 48); rdssl_sha1_transform(sha, (char *)salt1, 32); rdssl_sha1_transform(sha, (char *)salt2, 32); rdssl_sha1_complete(sha, (char *)shasig); rdssl_sha1_info_delete(sha); md5 = rdssl_md5_info_create(); rdssl_md5_clear(md5); rdssl_md5_transform(md5, (char *)in, 48); rdssl_md5_transform(md5, (char *)shasig, 20); rdssl_md5_complete(md5, (char *)out + i * 16); rdssl_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 = rdssl_md5_info_create(); rdssl_md5_clear(md5); rdssl_md5_transform(md5, (char *)in, 16); rdssl_md5_transform(md5, (char *)salt1, 32); rdssl_md5_transform(md5, (char *)salt2, 32); rdssl_md5_complete(md5, (char *)out); rdssl_md5_info_delete(md5); } /* * 16-byte sha1 hash */ void sec_hash_sha1_16(uint8 * out, uint8 * in, uint8 * salt1) { void * sha; sha = rdssl_sha1_info_create(); rdssl_sha1_clear(sha); rdssl_sha1_transform(&sha, (char *)in, 16); rdssl_sha1_transform(&sha, (char *)salt1, 16); rdssl_sha1_complete(&sha, (char *)out); rdssl_sha1_info_delete(sha); } /* create string from hash */ void sec_hash_to_string(char *out, int out_size, uint8 * in, int in_size) { int k; memset(out, 0, out_size); for (k = 0; k < in_size; k++, out += 2) { sprintf(out, "%.2x", in[k]); } } /* 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(g_sec_sign_key, key_block, 16); /* Generate export keys from next two blocks of 16 bytes */ sec_hash_16(g_sec_decrypt_key, &key_block[16], client_random, server_random); sec_hash_16(g_sec_encrypt_key, &key_block[32], client_random, server_random); if (rc4_key_size == 1) { DEBUG(("40-bit encryption enabled\n")); sec_make_40bit(g_sec_sign_key); sec_make_40bit(g_sec_decrypt_key); sec_make_40bit(g_sec_encrypt_key); g_rc4_key_len = 8; } else { DEBUG(("rc_4_key_size == %d, 128-bit encryption enabled\n", rc4_key_size)); g_rc4_key_len = 16; } /* Save initial RC4 keys as update keys */ memcpy(g_sec_decrypt_update_key, g_sec_decrypt_key, 16); memcpy(g_sec_encrypt_update_key, g_sec_encrypt_key, 16); /* Initialise RC4 state arrays */ rdssl_rc4_info_delete(g_rc4_decrypt_key); g_rc4_decrypt_key = rdssl_rc4_info_create(); rdssl_rc4_set_key(g_rc4_decrypt_key, (char *)g_sec_decrypt_key, g_rc4_key_len); rdssl_rc4_info_delete(g_rc4_encrypt_key); g_rc4_encrypt_key = rdssl_rc4_info_create(); rdssl_rc4_set_key(g_rc4_encrypt_key, (char *)g_sec_encrypt_key, g_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 = rdssl_sha1_info_create(); rdssl_sha1_clear(sha); rdssl_sha1_transform(sha, (char *)session_key, keylen); rdssl_sha1_transform(sha, (char *)pad_54, 40); rdssl_sha1_transform(sha, (char *)lenhdr, 4); rdssl_sha1_transform(sha, (char *)data, datalen); rdssl_sha1_complete(sha, (char *)shasig); rdssl_sha1_info_delete(sha); md5 = rdssl_md5_info_create(); rdssl_md5_clear(md5); rdssl_md5_transform(md5, (char *)session_key, keylen); rdssl_md5_transform(md5, (char *)pad_92, 48); rdssl_md5_transform(md5, (char *)shasig, 20); rdssl_md5_complete(md5, (char *)md5sig); rdssl_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 = rdssl_sha1_info_create(); rdssl_sha1_clear(sha); rdssl_sha1_transform(sha, (char *)update_key, g_rc4_key_len); rdssl_sha1_transform(sha, (char *)pad_54, 40); rdssl_sha1_transform(sha, (char *)key, g_rc4_key_len); rdssl_sha1_complete(sha, (char *)shasig); rdssl_sha1_info_delete(sha); md5 = rdssl_md5_info_create(); rdssl_md5_clear(md5); rdssl_md5_transform(md5, (char *)update_key, g_rc4_key_len); rdssl_md5_transform(md5, (char *)pad_92, 48); rdssl_md5_transform(md5, (char *)shasig, 20); rdssl_md5_complete(md5, (char *)key); rdssl_md5_info_delete(md5); update = rdssl_rc4_info_create(); rdssl_rc4_set_key(update, (char *)key, g_rc4_key_len); rdssl_rc4_crypt(update, (char *)key, (char *)key, g_rc4_key_len); rdssl_rc4_info_delete(update); if (g_rc4_key_len == 8) sec_make_40bit(key); } /* Encrypt data using RC4 */ static void sec_encrypt(uint8 * data, int length) { if (g_sec_encrypt_use_count == 4096) { sec_update(g_sec_encrypt_key, g_sec_encrypt_update_key); rdssl_rc4_set_key(g_rc4_encrypt_key, (char *)g_sec_encrypt_key, g_rc4_key_len); g_sec_encrypt_use_count = 0; } rdssl_rc4_crypt(g_rc4_encrypt_key, (char *)data, (char *)data, length); g_sec_encrypt_use_count++; } /* Decrypt data using RC4 */ void sec_decrypt(uint8 * data, int length) { if (g_sec_decrypt_use_count == 4096) { sec_update(g_sec_decrypt_key, g_sec_decrypt_update_key); rdssl_rc4_set_key(g_rc4_decrypt_key, (char *)g_sec_decrypt_key, g_rc4_key_len); g_sec_decrypt_use_count = 0; } rdssl_rc4_crypt(g_rc4_decrypt_key,(char *)data, (char *)data, length); g_sec_decrypt_use_count++; } /* Perform an RSA public key encryption operation */ static void sec_rsa_encrypt(uint8 * out, uint8 * in, int len, uint32 modulus_size, uint8 * modulus, uint8 * exponent) { rdssl_mod_exp((char *)out, 64, (char *)in, 32, (char *)modulus, 64, (char *)exponent, 4); } /* Initialise secure transport packet */ STREAM sec_init(uint32 flags, int maxlen) { int hdrlen; STREAM s; if (!g_licence_issued && !g_licence_error_result) 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; #ifdef WITH_SCARD scard_lock(SCARD_LOCK_SEC); #endif s_pop_layer(s, sec_hdr); if ((!g_licence_issued && !g_licence_error_result) || (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, g_sec_sign_key, g_rc4_key_len, s->p + 8, datalen); sec_encrypt(s->p + 8, datalen); } mcs_send_to_channel(s, channel); #ifdef WITH_SCARD scard_unlock(SCARD_LOCK_SEC); #endif } /* 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 = g_server_public_key_len + SEC_PADDING_SIZE; uint32 flags = SEC_EXCHANGE_PKT; STREAM s; s = sec_init(flags, length + 4); out_uint32_le(s, length); out_uint8p(s, g_sec_crypted_random, g_server_public_key_len); 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, uint32 selected_protocol) { int hostlen = 2 * strlen(g_hostname); int length = 162 + 76 + 12 + 4; unsigned int i; uint32 cluster_flags = 0; 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, 216); /* length */ out_uint16_le(s, (g_rdp_version >= RDP_V5) ? 4 : 1); /* RDP version. 1 == RDP4, 4 >= RDP5 to RDP8 */ 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); out_uint32_le(s, selected_protocol); /* End of client info */ /* Write a Client Cluster Data (TS_UD_CS_CLUSTER) */ out_uint16_le(s, SEC_TAG_CLI_CLUSTER); /* header.type */ out_uint16_le(s, 12); /* length */ cluster_flags |= SEC_CC_REDIRECTION_SUPPORTED; cluster_flags |= (SEC_CC_REDIRECT_VERSION_3 << 2); if (g_console_session || g_redirect_session_id != 0) cluster_flags |= SEC_CC_REDIRECT_SESSIONID_FIELD_VALID; out_uint32_le(s, cluster_flags); out_uint32(s, g_redirect_session_id); /* 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 RD_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); modulus_len -= SEC_PADDING_SIZE; if ((modulus_len < SEC_MODULUS_SIZE) || (modulus_len > SEC_MAX_MODULUS_SIZE)) { error("Bad server public key size (%u bits)\n", modulus_len * 8); return False; } in_uint8s(s, 8); /* modulus_bits, unknown */ in_uint8a(s, exponent, SEC_EXPONENT_SIZE); in_uint8a(s, modulus, modulus_len); in_uint8s(s, SEC_PADDING_SIZE); g_server_public_key_len = modulus_len; return s_check(s); } /* Parse a public signature structure */ static RD_BOOL sec_parse_public_sig(STREAM s, uint32 len, uint8 * modulus, uint8 * exponent) { uint8 signature[SEC_MAX_MODULUS_SIZE]; uint8 signature_[SEC_MAX_MODULUS_SIZE]; uint32 sig_len; if (len != 72) { return True; } memset(signature, 0, sizeof(signature)); sig_len = len - 8; in_uint8a(s, signature, sig_len); if(rdssl_sign_ok((char *)exponent, SEC_EXPONENT_SIZE, (char *)modulus, g_server_public_key_len, (char *)signature_, SEC_MODULUS_SIZE, (char *)signature, sig_len, (char *)g_testkey)) { DEBUG_RDP5(("key signature doesn't match test key\n")); } return s_check(s); } /* Parse a crypto information structure */ static RD_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; PCCERT_CONTEXT cacert, server_cert; BYTE *server_public_key; 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: if (!sec_parse_public_sig(s, length, modulus, exponent)) return False; break; default: unimpl("crypt tag 0x%x\n", tag); } s->p = next_tag; } } else { 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; PCCERT_CONTEXT ignorecert; DEBUG_RDP5(("Ignored certs left: %d\n", certcount)); in_uint32_le(s, ignorelen); DEBUG_RDP5(("Ignored Certificate length is %d\n", ignorelen)); ignorecert = rdssl_cert_read(s->p, ignorelen); in_uint8s(s, 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)); rdssl_cert_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 = rdssl_cert_read(s->p, cacert_len); in_uint8s(s, cacert_len); if (NULL == cacert) { error("Couldn't load CA Certificate from server\n"); return False; } in_uint32_le(s, cert_len); DEBUG_RDP5(("Certificate length is %d\n", cert_len)); server_cert = rdssl_cert_read(s->p, cert_len); in_uint8s(s, cert_len); if (NULL == server_cert) { rdssl_cert_free(cacert); error("Couldn't load Certificate from server\n"); return False; } if (!rdssl_certs_ok(server_cert, cacert)) { rdssl_cert_free(server_cert); rdssl_cert_free(cacert); error("Security error CA Certificate invalid\n"); return False; } rdssl_cert_free(cacert); in_uint8s(s, 16); /* Padding */ server_public_key = rdssl_cert_to_rkey(server_cert, &g_server_public_key_len); if (NULL == server_public_key) { DEBUG_RDP5(("Didn't parse X509 correctly\n")); rdssl_cert_free(server_cert); return False; } rdssl_cert_free(server_cert); if ((g_server_public_key_len < SEC_MODULUS_SIZE) || (g_server_public_key_len > SEC_MAX_MODULUS_SIZE)) { error("Bad server public key size (%u bits)\n", g_server_public_key_len * 8); rdssl_rkey_free(server_public_key); return False; } if (rdssl_rkey_get_exp_mod(server_public_key, exponent, SEC_EXPONENT_SIZE, modulus, SEC_MAX_MODULUS_SIZE) != 0) { error("Problem extracting RSA exponent, modulus"); rdssl_rkey_free(server_public_key); return False; } rdssl_rkey_free(server_public_key); return True; /* There's some garbage here we don't care about */ } return s_check_end(s); } /* Process crypto information blob */ static void sec_process_crypt_info(STREAM s) { uint8 *server_random = NULL; uint8 modulus[SEC_MAX_MODULUS_SIZE]; uint8 exponent[SEC_EXPONENT_SIZE]; uint32 rc4_key_size; memset(modulus, 0, sizeof(modulus)); memset(exponent, 0, sizeof(exponent)); 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_random(g_client_random); sec_rsa_encrypt(g_sec_crypted_random, g_client_random, SEC_RANDOM_SIZE, g_server_public_key_len, modulus, exponent); sec_generate_keys(g_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_rdp_version = RDP_V4; 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) { uint16 sec_flags; /* uint16 sec_flags_hi; */ 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 && !g_licence_error_result)) { /* TS_SECURITY_HEADER */ in_uint16_le(s, sec_flags); in_uint8s(s, 2); /* sec_flags_hi */ if (g_encryption) { if (sec_flags & SEC_ENCRYPT) { in_uint8s(s, 8); /* signature */ sec_decrypt(s->p, s->end - s->p); } if (sec_flags & SEC_LICENSE_PKT) { licence_process(s); continue; } if (sec_flags & SEC_REDIRECTION_PKT) /* 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 four values 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 } } else { if (sec_flags & SEC_LICENSE_PKT) { licence_process(s); continue; } s->p -= 4; } } if (channel != MCS_GLOBAL_CHANNEL) { channel_process(s, channel); if (rdpver != NULL) *rdpver = 0xff; return s; } return s; } return NULL; } /* Establish a secure connection */ RD_BOOL sec_connect(char *server, char *username, char *domain, char *password, RD_BOOL reconnect) { uint32 selected_proto; struct stream mcs_data; /* Start a MCS connect sequence */ if (!mcs_connect_start(server, username, domain, password, reconnect, &selected_proto)) return False; /* 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, selected_proto); /* finalize the MCS connect sequence */ if (!mcs_connect_finalize(&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; g_sec_encrypt_use_count = 0; g_sec_decrypt_use_count = 0; g_licence_issued = 0; g_licence_error_result = 0; mcs_reset_state(); }