d8b0f3782a
Makes it easier to debug things by seeing exactly where the protocol handling crashed.
1013 lines
27 KiB
C
1013 lines
27 KiB
C
/* -*- c-basic-offset: 8 -*-
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rdesktop: A Remote Desktop Protocol client.
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Protocol services - RDP encryption and licensing
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Copyright (C) Matthew Chapman <matthewc.unsw.edu.au> 1999-2008
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Copyright 2005-2011 Peter Astrand <astrand@cendio.se> for Cendio AB
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Copyright 2017-2018 Henrik Andersson <hean01@cendio.se> for Cendio AB
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This program is free software: you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation, either version 3 of the License, or
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(at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program. If not, see <http://www.gnu.org/licenses/>.
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*/
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#include "rdesktop.h"
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#include "ssl.h"
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extern char g_hostname[16];
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extern uint32 g_requested_session_width;
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extern uint32 g_requested_session_height;
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extern int g_dpi;
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extern unsigned int g_keylayout;
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extern int g_keyboard_type;
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extern int g_keyboard_subtype;
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extern int g_keyboard_functionkeys;
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extern RD_BOOL g_encryption;
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extern RD_BOOL g_licence_issued;
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extern RD_BOOL g_licence_error_result;
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extern RDP_VERSION g_rdp_version;
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extern RD_BOOL g_console_session;
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extern uint32 g_redirect_session_id;
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extern int g_server_depth;
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extern VCHANNEL g_channels[];
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extern unsigned int g_num_channels;
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extern uint8 g_client_random[SEC_RANDOM_SIZE];
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static int g_rc4_key_len;
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static RDSSL_RC4 g_rc4_decrypt_key;
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static RDSSL_RC4 g_rc4_encrypt_key;
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static uint32 g_server_public_key_len;
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static uint8 g_sec_sign_key[16];
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static uint8 g_sec_decrypt_key[16];
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static uint8 g_sec_encrypt_key[16];
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static uint8 g_sec_decrypt_update_key[16];
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static uint8 g_sec_encrypt_update_key[16];
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static uint8 g_sec_crypted_random[SEC_MAX_MODULUS_SIZE];
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uint16 g_server_rdp_version = 0;
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/* These values must be available to reset state - Session Directory */
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static int g_sec_encrypt_use_count = 0;
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static int g_sec_decrypt_use_count = 0;
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/*
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* I believe this is based on SSLv3 with the following differences:
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* MAC algorithm (5.2.3.1) uses only 32-bit length in place of seq_num/type/length fields
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* MAC algorithm uses SHA1 and MD5 for the two hash functions instead of one or other
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* key_block algorithm (6.2.2) uses 'X', 'YY', 'ZZZ' instead of 'A', 'BB', 'CCC'
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* key_block partitioning is different (16 bytes each: MAC secret, decrypt key, encrypt key)
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* encryption/decryption keys updated every 4096 packets
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* See http://wp.netscape.com/eng/ssl3/draft302.txt
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*/
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/*
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* 48-byte transformation used to generate master secret (6.1) and key material (6.2.2).
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* Both SHA1 and MD5 algorithms are used.
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*/
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void
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sec_hash_48(uint8 * out, uint8 * in, uint8 * salt1, uint8 * salt2, uint8 salt)
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{
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uint8 shasig[20];
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uint8 pad[4];
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RDSSL_SHA1 sha1;
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RDSSL_MD5 md5;
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int i;
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for (i = 0; i < 3; i++)
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{
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memset(pad, salt + i, i + 1);
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rdssl_sha1_init(&sha1);
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rdssl_sha1_update(&sha1, pad, i + 1);
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rdssl_sha1_update(&sha1, in, 48);
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rdssl_sha1_update(&sha1, salt1, 32);
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rdssl_sha1_update(&sha1, salt2, 32);
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rdssl_sha1_final(&sha1, shasig);
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rdssl_md5_init(&md5);
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rdssl_md5_update(&md5, in, 48);
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rdssl_md5_update(&md5, shasig, 20);
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rdssl_md5_final(&md5, &out[i * 16]);
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}
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}
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/*
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* 16-byte transformation used to generate export keys (6.2.2).
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*/
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void
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sec_hash_16(uint8 * out, uint8 * in, uint8 * salt1, uint8 * salt2)
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{
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RDSSL_MD5 md5;
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rdssl_md5_init(&md5);
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rdssl_md5_update(&md5, in, 16);
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rdssl_md5_update(&md5, salt1, 32);
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rdssl_md5_update(&md5, salt2, 32);
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rdssl_md5_final(&md5, out);
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}
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/*
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* 16-byte sha1 hash
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*/
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void
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sec_hash_sha1_16(uint8 * out, uint8 * in, uint8 * salt1)
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{
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RDSSL_SHA1 sha1;
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rdssl_sha1_init(&sha1);
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rdssl_sha1_update(&sha1, in, 16);
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rdssl_sha1_update(&sha1, salt1, 16);
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rdssl_sha1_final(&sha1, out);
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}
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/* create string from hash */
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void
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sec_hash_to_string(char *out, int out_size, uint8 * in, int in_size)
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{
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int k;
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memset(out, 0, out_size);
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for (k = 0; k < in_size; k++, out += 2)
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{
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sprintf(out, "%.2x", in[k]);
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}
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}
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/* Reduce key entropy from 64 to 40 bits */
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static void
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sec_make_40bit(uint8 * key)
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{
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key[0] = 0xd1;
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key[1] = 0x26;
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key[2] = 0x9e;
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}
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/* Generate encryption keys given client and server randoms */
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static void
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sec_generate_keys(uint8 * client_random, uint8 * server_random, int rc4_key_size)
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{
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uint8 pre_master_secret[48];
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uint8 master_secret[48];
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uint8 key_block[48];
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/* Construct pre-master secret */
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memcpy(pre_master_secret, client_random, 24);
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memcpy(pre_master_secret + 24, server_random, 24);
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/* Generate master secret and then key material */
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sec_hash_48(master_secret, pre_master_secret, client_random, server_random, 'A');
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sec_hash_48(key_block, master_secret, client_random, server_random, 'X');
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/* First 16 bytes of key material is MAC secret */
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memcpy(g_sec_sign_key, key_block, 16);
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/* Generate export keys from next two blocks of 16 bytes */
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sec_hash_16(g_sec_decrypt_key, &key_block[16], client_random, server_random);
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sec_hash_16(g_sec_encrypt_key, &key_block[32], client_random, server_random);
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if (rc4_key_size == 1)
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{
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logger(Protocol, Debug, "sec_generate_keys(), 40-bit encryption enabled");
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sec_make_40bit(g_sec_sign_key);
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sec_make_40bit(g_sec_decrypt_key);
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sec_make_40bit(g_sec_encrypt_key);
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g_rc4_key_len = 8;
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}
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else
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{
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logger(Protocol, Debug,
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"sec_generate_key(), rc_4_key_size == %d, 128-bit encryption enabled",
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rc4_key_size);
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g_rc4_key_len = 16;
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}
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/* Save initial RC4 keys as update keys */
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memcpy(g_sec_decrypt_update_key, g_sec_decrypt_key, 16);
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memcpy(g_sec_encrypt_update_key, g_sec_encrypt_key, 16);
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/* Initialise RC4 state arrays */
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rdssl_rc4_set_key(&g_rc4_decrypt_key, g_sec_decrypt_key, g_rc4_key_len);
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rdssl_rc4_set_key(&g_rc4_encrypt_key, g_sec_encrypt_key, g_rc4_key_len);
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}
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static uint8 pad_54[40] = {
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54, 54, 54, 54, 54, 54, 54, 54, 54, 54, 54, 54, 54, 54, 54, 54, 54,
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54, 54, 54,
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54, 54, 54, 54, 54, 54, 54, 54, 54, 54, 54, 54, 54, 54, 54, 54, 54,
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54, 54, 54
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};
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static uint8 pad_92[48] = {
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92, 92, 92, 92, 92, 92, 92, 92, 92, 92, 92, 92, 92, 92, 92, 92, 92,
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92, 92, 92, 92, 92, 92, 92,
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92, 92, 92, 92, 92, 92, 92, 92, 92, 92, 92, 92, 92, 92, 92, 92, 92,
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92, 92, 92, 92, 92, 92, 92
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};
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/* Output a uint32 into a buffer (little-endian) */
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void
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buf_out_uint32(uint8 * buffer, uint32 value)
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{
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buffer[0] = (value) & 0xff;
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buffer[1] = (value >> 8) & 0xff;
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buffer[2] = (value >> 16) & 0xff;
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buffer[3] = (value >> 24) & 0xff;
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}
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/* Generate a MAC hash (5.2.3.1), using a combination of SHA1 and MD5 */
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void
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sec_sign(uint8 * signature, int siglen, uint8 * session_key, int keylen, uint8 * data, int datalen)
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{
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uint8 shasig[20];
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uint8 md5sig[16];
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uint8 lenhdr[4];
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RDSSL_SHA1 sha1;
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RDSSL_MD5 md5;
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buf_out_uint32(lenhdr, datalen);
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rdssl_sha1_init(&sha1);
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rdssl_sha1_update(&sha1, session_key, keylen);
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rdssl_sha1_update(&sha1, pad_54, 40);
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rdssl_sha1_update(&sha1, lenhdr, 4);
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rdssl_sha1_update(&sha1, data, datalen);
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rdssl_sha1_final(&sha1, shasig);
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rdssl_md5_init(&md5);
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rdssl_md5_update(&md5, session_key, keylen);
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rdssl_md5_update(&md5, pad_92, 48);
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rdssl_md5_update(&md5, shasig, 20);
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rdssl_md5_final(&md5, md5sig);
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memcpy(signature, md5sig, siglen);
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}
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/* Update an encryption key */
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static void
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sec_update(uint8 * key, uint8 * update_key)
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{
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uint8 shasig[20];
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RDSSL_SHA1 sha1;
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RDSSL_MD5 md5;
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RDSSL_RC4 update;
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rdssl_sha1_init(&sha1);
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rdssl_sha1_update(&sha1, update_key, g_rc4_key_len);
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rdssl_sha1_update(&sha1, pad_54, 40);
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rdssl_sha1_update(&sha1, key, g_rc4_key_len);
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rdssl_sha1_final(&sha1, shasig);
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rdssl_md5_init(&md5);
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rdssl_md5_update(&md5, update_key, g_rc4_key_len);
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rdssl_md5_update(&md5, pad_92, 48);
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rdssl_md5_update(&md5, shasig, 20);
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rdssl_md5_final(&md5, key);
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rdssl_rc4_set_key(&update, key, g_rc4_key_len);
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rdssl_rc4_crypt(&update, key, key, g_rc4_key_len);
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if (g_rc4_key_len == 8)
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sec_make_40bit(key);
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}
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/* Encrypt data using RC4 */
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static void
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sec_encrypt(uint8 * data, int length)
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{
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if (g_sec_encrypt_use_count == 4096)
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{
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sec_update(g_sec_encrypt_key, g_sec_encrypt_update_key);
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rdssl_rc4_set_key(&g_rc4_encrypt_key, g_sec_encrypt_key, g_rc4_key_len);
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g_sec_encrypt_use_count = 0;
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}
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rdssl_rc4_crypt(&g_rc4_encrypt_key, data, data, length);
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g_sec_encrypt_use_count++;
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}
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/* Decrypt data using RC4 */
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void
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sec_decrypt(uint8 * data, int length)
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{
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if (length <= 0)
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return;
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if (g_sec_decrypt_use_count == 4096)
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{
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sec_update(g_sec_decrypt_key, g_sec_decrypt_update_key);
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rdssl_rc4_set_key(&g_rc4_decrypt_key, g_sec_decrypt_key, g_rc4_key_len);
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g_sec_decrypt_use_count = 0;
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}
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rdssl_rc4_crypt(&g_rc4_decrypt_key, data, data, length);
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g_sec_decrypt_use_count++;
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}
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/* Perform an RSA public key encryption operation */
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static void
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sec_rsa_encrypt(uint8 * out, uint8 * in, int len, uint32 modulus_size, uint8 * modulus,
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uint8 * exponent)
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{
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rdssl_rsa_encrypt(out, in, len, modulus_size, modulus, exponent);
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}
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/* Initialise secure transport packet */
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STREAM
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sec_init(uint32 flags, int maxlen)
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{
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int hdrlen;
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STREAM s;
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if (!g_licence_issued && !g_licence_error_result)
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hdrlen = (flags & SEC_ENCRYPT) ? 12 : 4;
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else
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hdrlen = (flags & SEC_ENCRYPT) ? 12 : 0;
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s = mcs_init(maxlen + hdrlen);
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s_push_layer(s, sec_hdr, hdrlen);
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return s;
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}
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/* Transmit secure transport packet over specified channel */
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void
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sec_send_to_channel(STREAM s, uint32 flags, uint16 channel)
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{
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int datalen;
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#ifdef WITH_SCARD
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scard_lock(SCARD_LOCK_SEC);
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#endif
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s_pop_layer(s, sec_hdr);
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if ((!g_licence_issued && !g_licence_error_result) || (flags & SEC_ENCRYPT))
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out_uint32_le(s, flags);
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if (flags & SEC_ENCRYPT)
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{
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flags &= ~SEC_ENCRYPT;
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datalen = s->end - s->p - 8;
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sec_sign(s->p, 8, g_sec_sign_key, g_rc4_key_len, s->p + 8, datalen);
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sec_encrypt(s->p + 8, datalen);
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}
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mcs_send_to_channel(s, channel);
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#ifdef WITH_SCARD
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scard_unlock(SCARD_LOCK_SEC);
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#endif
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}
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/* Transmit secure transport packet */
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void
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sec_send(STREAM s, uint32 flags)
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{
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sec_send_to_channel(s, flags, MCS_GLOBAL_CHANNEL);
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}
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/* Transfer the client random to the server */
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static void
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sec_establish_key(void)
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{
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uint32 length = g_server_public_key_len + SEC_PADDING_SIZE;
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uint32 flags = SEC_EXCHANGE_PKT;
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STREAM s;
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s = sec_init(flags, length + 4);
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out_uint32_le(s, length);
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out_uint8p(s, g_sec_crypted_random, g_server_public_key_len);
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out_uint8s(s, SEC_PADDING_SIZE);
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s_mark_end(s);
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sec_send(s, flags);
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}
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/* Output connect initial data blob */
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static void
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sec_out_mcs_connect_initial_pdu(STREAM s, uint32 selected_protocol)
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{
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int length = 162 + 76 + 12 + 4 + (g_dpi > 0 ? 18 : 0);
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unsigned int i;
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uint32 rdpversion = RDP_40;
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uint16 capflags = RNS_UD_CS_SUPPORT_ERRINFO_PDU;
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uint16 colorsupport = RNS_UD_24BPP_SUPPORT | RNS_UD_16BPP_SUPPORT | RNS_UD_32BPP_SUPPORT;
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uint32 physwidth, physheight, desktopscale, devicescale;
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logger(Protocol, Debug, "%s()", __func__);
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if (g_rdp_version >= RDP_V5)
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rdpversion = RDP_50;
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if (g_num_channels > 0)
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length += g_num_channels * 12 + 8;
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/* Generic Conference Control (T.124) ConferenceCreateRequest */
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out_uint16_be(s, 5);
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out_uint16_be(s, 0x14);
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out_uint8(s, 0x7c);
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out_uint16_be(s, 1);
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out_uint16_be(s, (length | 0x8000)); /* remaining length */
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out_uint16_be(s, 8); /* length? */
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out_uint16_be(s, 16);
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out_uint8(s, 0);
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out_uint16_le(s, 0xc001);
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out_uint8(s, 0);
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out_uint32_le(s, 0x61637544); /* OEM ID: "Duca", as in Ducati. */
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out_uint16_be(s, ((length - 14) | 0x8000)); /* remaining length */
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/* Client information (TS_UD_CS_CORE) */
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out_uint16_le(s, CS_CORE); /* type */
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out_uint16_le(s, 216 + (g_dpi > 0 ? 18 : 0)); /* length */
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out_uint32_le(s, rdpversion); /* version */
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out_uint16_le(s, g_requested_session_width); /* desktopWidth */
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out_uint16_le(s, g_requested_session_height); /* desktopHeight */
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out_uint16_le(s, RNS_UD_COLOR_8BPP); /* colorDepth */
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out_uint16_le(s, RNS_UD_SAS_DEL); /* SASSequence */
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out_uint32_le(s, g_keylayout); /* keyboardLayout */
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/*
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* According to s.1.7 of MS-RDPESC if the build number is at least 4,304,
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* SCREDIR_VERSION_LONGHORN is assumed; otherwise SCREDIR_VERSIONXP is to be used
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*/
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out_uint32_le(s, 2600); /* Client build. We are now 2600 compatible :-) */
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/* Unicode name of client, padded to 32 bytes */
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out_utf16s_padded(s, g_hostname, 32, 0x00);
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out_uint32_le(s, g_keyboard_type); /* keyboardType */
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out_uint32_le(s, g_keyboard_subtype); /* keyboardSubtype */
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out_uint32_le(s, g_keyboard_functionkeys); /* keyboardFunctionKey */
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out_uint8s(s, 64); /* imeFileName */
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out_uint16_le(s, RNS_UD_COLOR_8BPP); /* postBeta2ColorDepth (overrides colorDepth) */
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out_uint16_le(s, 1); /* clientProductId (should be 1) */
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out_uint32_le(s, 0); /* serialNumber (should be 0) */
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/* highColorDepth (overrides postBeta2ColorDepth). Capped at 24BPP.
|
|
To get 32BPP sessions, we need to set a capability flag. */
|
|
out_uint16_le(s, MIN(g_server_depth, 24));
|
|
if (g_server_depth == 32)
|
|
capflags |= RNS_UD_CS_WANT_32BPP_SESSION;
|
|
|
|
out_uint16_le(s, colorsupport); /* supportedColorDepths */
|
|
out_uint16_le(s, capflags); /* earlyCapabilityFlags */
|
|
out_uint8s(s, 64); /* clientDigProductId */
|
|
out_uint8(s, 0); /* connectionType */
|
|
out_uint8(s, 0); /* pad */
|
|
out_uint32_le(s, selected_protocol); /* serverSelectedProtocol */
|
|
if (g_dpi > 0)
|
|
{
|
|
/* Extended client info describing monitor geometry */
|
|
utils_calculate_dpi_scale_factors(g_requested_session_width,
|
|
g_requested_session_height, g_dpi, &physwidth,
|
|
&physheight, &desktopscale, &devicescale);
|
|
out_uint32_le(s, physwidth); /* physicalwidth */
|
|
out_uint32_le(s, physheight); /* physicalheight */
|
|
out_uint16_le(s, ORIENTATION_LANDSCAPE); /* Orientation */
|
|
out_uint32_le(s, desktopscale); /* DesktopScaleFactor */
|
|
out_uint32_le(s, devicescale); /* DeviceScaleFactor */
|
|
}
|
|
|
|
/* Write a Client Cluster Data (TS_UD_CS_CLUSTER) */
|
|
uint32 cluster_flags = 0;
|
|
out_uint16_le(s, CS_CLUSTER); /* header.type */
|
|
out_uint16_le(s, 12); /* length */
|
|
|
|
cluster_flags |= SEC_CC_REDIRECTION_SUPPORTED;
|
|
cluster_flags |= (SEC_CC_REDIRECT_VERSION_4 << 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 (TS_UD_CS_SEC) */
|
|
out_uint16_le(s, CS_SECURITY); /* type */
|
|
out_uint16_le(s, 12); /* length */
|
|
out_uint32_le(s, g_encryption ? 0x3 : 0); /* encryptionMethods */
|
|
out_uint32(s, 0); /* extEncryptionMethods */
|
|
|
|
/* Channel definitions (TS_UD_CS_NET) */
|
|
logger(Protocol, Debug, "sec_out_mcs_data(), g_num_channels is %d", g_num_channels);
|
|
if (g_num_channels > 0)
|
|
{
|
|
out_uint16_le(s, CS_NET); /* type */
|
|
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++)
|
|
{
|
|
logger(Protocol, Debug, "sec_out_mcs_data(), requesting channel %s",
|
|
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)
|
|
{
|
|
logger(Protocol, Error, "sec_parse_public_key(), magic (0x%x) != SEC_RSA_MAGIC",
|
|
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))
|
|
{
|
|
logger(Protocol, Error,
|
|
"sec_parse_public_key(), invalid public key size (%u bits) from server",
|
|
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];
|
|
uint32 sig_len;
|
|
|
|
if (len != 72)
|
|
{
|
|
return True;
|
|
}
|
|
memset(signature, 0, sizeof(signature));
|
|
sig_len = len - 8;
|
|
in_uint8a(s, signature, sig_len);
|
|
return rdssl_sig_ok(exponent, SEC_EXPONENT_SIZE, modulus, g_server_public_key_len,
|
|
signature, sig_len);
|
|
}
|
|
|
|
/* 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;
|
|
RDSSL_CERT *cacert, *server_cert;
|
|
RDSSL_RKEY *server_public_key;
|
|
uint16 tag, length;
|
|
uint8 *next_tag, *end;
|
|
|
|
logger(Protocol, Debug, "%s()", __func__);
|
|
|
|
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 */
|
|
logger(Protocol, Debug, "sec_parse_crypt_info(), got ENCRYPTION_LEVEL_NONE");
|
|
return False;
|
|
}
|
|
|
|
in_uint32_le(s, random_len);
|
|
in_uint32_le(s, rsa_info_len);
|
|
|
|
if (random_len != SEC_RANDOM_SIZE)
|
|
{
|
|
logger(Protocol, Error, "sec_parse_crypt_info(), got random len %d, expected %d",
|
|
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)
|
|
{
|
|
logger(Protocol, Error, "sec_parse_crypt_info(), end > s->end");
|
|
return False;
|
|
}
|
|
|
|
in_uint32_le(s, flags); /* 1 = RDP4-style, 0x80000002 = X.509 */
|
|
if (flags & 1)
|
|
{
|
|
logger(Protocol, Debug,
|
|
"sec_parse_crypt_info(), We're going for the RDP4-style encryption");
|
|
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))
|
|
{
|
|
logger(Protocol, Error,
|
|
"sec_parse_crypt_info(), invalid public key");
|
|
return False;
|
|
}
|
|
logger(Protocol, Debug,
|
|
"sec_parse_crypt_info(), got public key");
|
|
|
|
break;
|
|
|
|
case SEC_TAG_KEYSIG:
|
|
if (!sec_parse_public_sig(s, length, modulus, exponent))
|
|
{
|
|
logger(Protocol, Error,
|
|
"sec_parse_crypt_info(), invalid public sig");
|
|
return False;
|
|
}
|
|
break;
|
|
|
|
default:
|
|
logger(Protocol, Warning,
|
|
"sec_parse_crypt_info(), unhandled crypt tag 0x%x",
|
|
tag);
|
|
}
|
|
|
|
s->p = next_tag;
|
|
}
|
|
}
|
|
else
|
|
{
|
|
uint32 certcount;
|
|
|
|
logger(Protocol, Debug,
|
|
"sec_parse_crypt_info(), We're going for the RDP5-style encryption");
|
|
in_uint32_le(s, certcount); /* Number of certificates */
|
|
if (certcount < 2)
|
|
{
|
|
logger(Protocol, Error,
|
|
"sec_parse_crypt_info(), server didn't send enough x509 certificates");
|
|
return False;
|
|
}
|
|
for (; certcount > 2; certcount--)
|
|
{ /* ignore all the certificates between the root and the signing CA */
|
|
uint32 ignorelen;
|
|
RDSSL_CERT *ignorecert;
|
|
|
|
in_uint32_le(s, ignorelen);
|
|
ignorecert = rdssl_cert_read(s->p, ignorelen);
|
|
in_uint8s(s, ignorelen);
|
|
if (ignorecert == NULL)
|
|
{ /* XXX: error out? */
|
|
logger(Protocol, Error,
|
|
"sec_parse_crypt_info(), got a bad cert: this will probably screw up the rest of the communication");
|
|
}
|
|
else
|
|
{
|
|
rdssl_cert_free(ignorecert);
|
|
}
|
|
}
|
|
/* 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);
|
|
logger(Protocol, Debug,
|
|
"sec_parse_crypt_info(), server CA Certificate length is %d", cacert_len);
|
|
cacert = rdssl_cert_read(s->p, cacert_len);
|
|
in_uint8s(s, cacert_len);
|
|
if (NULL == cacert)
|
|
{
|
|
logger(Protocol, Error,
|
|
"sec_parse_crypt_info(), couldn't load CA Certificate from server");
|
|
return False;
|
|
}
|
|
in_uint32_le(s, cert_len);
|
|
logger(Protocol, Debug, "sec_parse_crypt_info(), certificate length is %d",
|
|
cert_len);
|
|
server_cert = rdssl_cert_read(s->p, cert_len);
|
|
in_uint8s(s, cert_len);
|
|
if (NULL == server_cert)
|
|
{
|
|
rdssl_cert_free(cacert);
|
|
logger(Protocol, Error,
|
|
"sec_parse_crypt_info(), couldn't load Certificate from server");
|
|
return False;
|
|
}
|
|
if (!rdssl_certs_ok(server_cert, cacert))
|
|
{
|
|
rdssl_cert_free(server_cert);
|
|
rdssl_cert_free(cacert);
|
|
logger(Protocol, Error,
|
|
"sec_parse_crypt_info(), security error, CA Certificate invalid");
|
|
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)
|
|
{
|
|
logger(Protocol, Debug,
|
|
"sec_parse_crypt_info(). failed to parse X509 correctly");
|
|
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))
|
|
{
|
|
logger(Protocol, Error,
|
|
"sec_parse_crypt_info(), bad server public key size (%u bits)",
|
|
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)
|
|
{
|
|
logger(Protocol, Error,
|
|
"sec_parse_crypt_info(), 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;
|
|
|
|
logger(Protocol, Debug, "%s()", __func__);
|
|
|
|
memset(modulus, 0, sizeof(modulus));
|
|
memset(exponent, 0, sizeof(exponent));
|
|
if (!sec_parse_crypt_info(s, &rc4_key_size, &server_random, modulus, exponent))
|
|
return;
|
|
|
|
logger(Protocol, Debug, "sec_parse_crypt_info(), generating client random");
|
|
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);
|
|
logger(Protocol, Debug, "sec_process_srv_info(), server RDP version is %d",
|
|
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);
|
|
logger(Protocol, Debug, "%s()", __func__);
|
|
|
|
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:
|
|
logger(Protocol, Debug, "%s(), SEC_TAG_SRV_INFO", __func__);
|
|
sec_process_srv_info(s);
|
|
break;
|
|
|
|
case SEC_TAG_SRV_CRYPT:
|
|
logger(Protocol, Debug, "%s(), SEC_TAG_SRV_CRYPT", __func__);
|
|
sec_process_crypt_info(s);
|
|
break;
|
|
|
|
case SEC_TAG_SRV_CHANNELS:
|
|
logger(Protocol, Debug, "%s(), SEC_TAG_SRV_CHANNELS", __func__);
|
|
/* FIXME: We should parse this information and
|
|
use it to map RDP5 channels to MCS
|
|
channels */
|
|
break;
|
|
|
|
default:
|
|
logger(Protocol, Warning, "Unhandled response tag 0x%x", tag);
|
|
}
|
|
|
|
s->p = next_tag;
|
|
}
|
|
}
|
|
|
|
/* Receive secure transport packet */
|
|
STREAM
|
|
sec_recv(RD_BOOL * is_fastpath)
|
|
{
|
|
uint8 fastpath_hdr, fastpath_flags;
|
|
uint16 sec_flags;
|
|
uint16 channel;
|
|
STREAM s;
|
|
struct stream packet;
|
|
|
|
while ((s = mcs_recv(&channel, is_fastpath, &fastpath_hdr)) != NULL)
|
|
{
|
|
packet = *s;
|
|
if (*is_fastpath == True)
|
|
{
|
|
/* If fastpath packet is encrypted, read data
|
|
signature and decrypt */
|
|
/* FIXME: extracting flags from hdr could be made less obscure */
|
|
fastpath_flags = (fastpath_hdr & 0xC0) >> 6;
|
|
if (fastpath_flags & FASTPATH_OUTPUT_ENCRYPTED)
|
|
{
|
|
if (!s_check_rem(s, 8)) {
|
|
rdp_protocol_error("consume fastpath signature from stream would overrun", &packet);
|
|
}
|
|
|
|
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); /* skip sec_flags_hi */
|
|
|
|
if (g_encryption)
|
|
{
|
|
if (sec_flags & SEC_ENCRYPT)
|
|
{
|
|
if (!s_check_rem(s, 8)) {
|
|
rdp_protocol_error("consume encrypt signature from stream would overrun", &packet);
|
|
}
|
|
|
|
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)
|
|
{
|
|
uint8 swapbyte;
|
|
|
|
if (!s_check_rem(s, 8)) {
|
|
rdp_protocol_error("consume redirect signature from stream would overrun", &packet);
|
|
}
|
|
|
|
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 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;
|
|
}
|
|
}
|
|
}
|
|
else
|
|
{
|
|
if (sec_flags & SEC_LICENSE_PKT)
|
|
{
|
|
licence_process(s);
|
|
continue;
|
|
}
|
|
s->p -= 4;
|
|
}
|
|
}
|
|
|
|
if (channel != MCS_GLOBAL_CHANNEL)
|
|
{
|
|
channel_process(s, channel);
|
|
continue;
|
|
}
|
|
|
|
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_connect_initial_pdu(&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)
|
|
{
|
|
/* Perform a User-initiated disconnect sequence, see
|
|
[MS-RDPBCGR] 1.3.1.4 Disconnect Sequences */
|
|
mcs_disconnect(RN_USER_REQUESTED);
|
|
}
|
|
|
|
/* 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();
|
|
}
|