1 |
/* |
/* -*- c-basic-offset: 8 -*- |
2 |
rdesktop: A Remote Desktop Protocol client. |
rdesktop: A Remote Desktop Protocol client. |
3 |
Protocol services - RDP encryption and licensing |
Protocol services - RDP encryption and licensing |
4 |
Copyright (C) Matthew Chapman 1999-2002 |
Copyright (C) Matthew Chapman 1999-2005 |
5 |
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|
6 |
This program is free software; you can redistribute it and/or modify |
This program is free software; you can redistribute it and/or modify |
7 |
it under the terms of the GNU General Public License as published by |
it under the terms of the GNU General Public License as published by |
20 |
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21 |
#include "rdesktop.h" |
#include "rdesktop.h" |
22 |
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#ifdef WITH_OPENSSL |
|
23 |
#include <openssl/rc4.h> |
#include <openssl/rc4.h> |
24 |
#include <openssl/md5.h> |
#include <openssl/md5.h> |
25 |
#include <openssl/sha.h> |
#include <openssl/sha.h> |
26 |
#include <openssl/bn.h> |
#include <openssl/bn.h> |
27 |
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#include <openssl/x509v3.h> |
28 |
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29 |
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#if defined(OPENSSL_VERSION_NUMBER) && (OPENSSL_VERSION_NUMBER >= 0x0090800f) |
30 |
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#define D2I_X509_CONST const |
31 |
#else |
#else |
32 |
#include "crypto/rc4.h" |
#define D2I_X509_CONST |
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#include "crypto/md5.h" |
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#include "crypto/sha.h" |
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#include "crypto/bn.h" |
|
33 |
#endif |
#endif |
34 |
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|
35 |
extern char hostname[16]; |
extern char g_hostname[16]; |
36 |
extern int width; |
extern int g_width; |
37 |
extern int height; |
extern int g_height; |
38 |
extern int keylayout; |
extern unsigned int g_keylayout; |
39 |
extern BOOL encryption; |
extern int g_keyboard_type; |
40 |
extern BOOL licence_issued; |
extern int g_keyboard_subtype; |
41 |
extern int server_bpp; |
extern int g_keyboard_functionkeys; |
42 |
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extern BOOL g_encryption; |
43 |
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extern BOOL g_licence_issued; |
44 |
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extern BOOL g_use_rdp5; |
45 |
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extern BOOL g_console_session; |
46 |
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extern int g_server_depth; |
47 |
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extern uint16 mcs_userid; |
48 |
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extern VCHANNEL g_channels[]; |
49 |
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extern unsigned int g_num_channels; |
50 |
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51 |
static int rc4_key_len; |
static int rc4_key_len; |
52 |
static RC4_KEY rc4_decrypt_key; |
static RC4_KEY rc4_decrypt_key; |
53 |
static RC4_KEY rc4_encrypt_key; |
static RC4_KEY rc4_encrypt_key; |
54 |
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static RSA *server_public_key; |
55 |
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static uint32 server_public_key_len; |
56 |
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|
57 |
static uint8 sec_sign_key[16]; |
static uint8 sec_sign_key[16]; |
58 |
static uint8 sec_decrypt_key[16]; |
static uint8 sec_decrypt_key[16]; |
59 |
static uint8 sec_encrypt_key[16]; |
static uint8 sec_encrypt_key[16]; |
60 |
static uint8 sec_decrypt_update_key[16]; |
static uint8 sec_decrypt_update_key[16]; |
61 |
static uint8 sec_encrypt_update_key[16]; |
static uint8 sec_encrypt_update_key[16]; |
62 |
static uint8 sec_crypted_random[SEC_MODULUS_SIZE]; |
static uint8 sec_crypted_random[SEC_MAX_MODULUS_SIZE]; |
63 |
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64 |
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uint16 g_server_rdp_version = 0; |
65 |
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66 |
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/* These values must be available to reset state - Session Directory */ |
67 |
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static int sec_encrypt_use_count = 0; |
68 |
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static int sec_decrypt_use_count = 0; |
69 |
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70 |
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/* |
71 |
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* I believe this is based on SSLv3 with the following differences: |
72 |
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* MAC algorithm (5.2.3.1) uses only 32-bit length in place of seq_num/type/length fields |
73 |
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* MAC algorithm uses SHA1 and MD5 for the two hash functions instead of one or other |
74 |
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* key_block algorithm (6.2.2) uses 'X', 'YY', 'ZZZ' instead of 'A', 'BB', 'CCC' |
75 |
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* key_block partitioning is different (16 bytes each: MAC secret, decrypt key, encrypt key) |
76 |
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* encryption/decryption keys updated every 4096 packets |
77 |
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* See http://wp.netscape.com/eng/ssl3/draft302.txt |
78 |
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*/ |
79 |
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|
80 |
/* |
/* |
81 |
* General purpose 48-byte transformation, using two 32-byte salts (generally, |
* 48-byte transformation used to generate master secret (6.1) and key material (6.2.2). |
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* a client and server salt) and a global salt value used for padding. |
|
82 |
* Both SHA1 and MD5 algorithms are used. |
* Both SHA1 and MD5 algorithms are used. |
83 |
*/ |
*/ |
84 |
void |
void |
109 |
} |
} |
110 |
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|
111 |
/* |
/* |
112 |
* Weaker 16-byte transformation, also using two 32-byte salts, but |
* 16-byte transformation used to generate export keys (6.2.2). |
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* only using a single round of MD5. |
|
113 |
*/ |
*/ |
114 |
void |
void |
115 |
sec_hash_16(uint8 * out, uint8 * in, uint8 * salt1, uint8 * salt2) |
sec_hash_16(uint8 * out, uint8 * in, uint8 * salt1, uint8 * salt2) |
132 |
key[2] = 0x9e; |
key[2] = 0x9e; |
133 |
} |
} |
134 |
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|
135 |
/* Generate a session key and RC4 keys, given client and server randoms */ |
/* Generate encryption keys given client and server randoms */ |
136 |
static void |
static void |
137 |
sec_generate_keys(uint8 * client_key, uint8 * server_key, int rc4_key_size) |
sec_generate_keys(uint8 * client_random, uint8 * server_random, int rc4_key_size) |
138 |
{ |
{ |
139 |
uint8 session_key[48]; |
uint8 pre_master_secret[48]; |
140 |
uint8 temp_hash[48]; |
uint8 master_secret[48]; |
141 |
uint8 input[48]; |
uint8 key_block[48]; |
142 |
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|
143 |
/* Construct input data to hash */ |
/* Construct pre-master secret */ |
144 |
memcpy(input, client_key, 24); |
memcpy(pre_master_secret, client_random, 24); |
145 |
memcpy(input + 24, server_key, 24); |
memcpy(pre_master_secret + 24, server_random, 24); |
146 |
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|
147 |
/* Generate session key - two rounds of sec_hash_48 */ |
/* Generate master secret and then key material */ |
148 |
sec_hash_48(temp_hash, input, client_key, server_key, 65); |
sec_hash_48(master_secret, pre_master_secret, client_random, server_random, 'A'); |
149 |
sec_hash_48(session_key, temp_hash, client_key, server_key, 88); |
sec_hash_48(key_block, master_secret, client_random, server_random, 'X'); |
150 |
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|
151 |
/* Store first 16 bytes of session key, for generating signatures */ |
/* First 16 bytes of key material is MAC secret */ |
152 |
memcpy(sec_sign_key, session_key, 16); |
memcpy(sec_sign_key, key_block, 16); |
153 |
|
|
154 |
/* Generate RC4 keys */ |
/* Generate export keys from next two blocks of 16 bytes */ |
155 |
sec_hash_16(sec_decrypt_key, &session_key[16], client_key, server_key); |
sec_hash_16(sec_decrypt_key, &key_block[16], client_random, server_random); |
156 |
sec_hash_16(sec_encrypt_key, &session_key[32], client_key, server_key); |
sec_hash_16(sec_encrypt_key, &key_block[32], client_random, server_random); |
157 |
|
|
158 |
if (rc4_key_size == 1) |
if (rc4_key_size == 1) |
159 |
{ |
{ |
165 |
} |
} |
166 |
else |
else |
167 |
{ |
{ |
168 |
DEBUG(("128-bit encryption enabled\n")); |
DEBUG(("rc_4_key_size == %d, 128-bit encryption enabled\n", rc4_key_size)); |
169 |
rc4_key_len = 16; |
rc4_key_len = 16; |
170 |
} |
} |
171 |
|
|
202 |
buffer[3] = (value >> 24) & 0xff; |
buffer[3] = (value >> 24) & 0xff; |
203 |
} |
} |
204 |
|
|
205 |
/* Generate a signature hash, using a combination of SHA1 and MD5 */ |
/* Generate a MAC hash (5.2.3.1), using a combination of SHA1 and MD5 */ |
206 |
void |
void |
207 |
sec_sign(uint8 * signature, int siglen, uint8 * session_key, int keylen, uint8 * data, int datalen) |
sec_sign(uint8 * signature, int siglen, uint8 * session_key, int keylen, uint8 * data, int datalen) |
208 |
{ |
{ |
230 |
memcpy(signature, md5sig, siglen); |
memcpy(signature, md5sig, siglen); |
231 |
} |
} |
232 |
|
|
233 |
/* Update an encryption key - similar to the signing process */ |
/* Update an encryption key */ |
234 |
static void |
static void |
235 |
sec_update(uint8 * key, uint8 * update_key) |
sec_update(uint8 * key, uint8 * update_key) |
236 |
{ |
{ |
262 |
static void |
static void |
263 |
sec_encrypt(uint8 * data, int length) |
sec_encrypt(uint8 * data, int length) |
264 |
{ |
{ |
265 |
static int use_count; |
if (sec_encrypt_use_count == 4096) |
|
|
|
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if (use_count == 4096) |
|
266 |
{ |
{ |
267 |
sec_update(sec_encrypt_key, sec_encrypt_update_key); |
sec_update(sec_encrypt_key, sec_encrypt_update_key); |
268 |
RC4_set_key(&rc4_encrypt_key, rc4_key_len, sec_encrypt_key); |
RC4_set_key(&rc4_encrypt_key, rc4_key_len, sec_encrypt_key); |
269 |
use_count = 0; |
sec_encrypt_use_count = 0; |
270 |
} |
} |
271 |
|
|
272 |
RC4(&rc4_encrypt_key, length, data, data); |
RC4(&rc4_encrypt_key, length, data, data); |
273 |
use_count++; |
sec_encrypt_use_count++; |
274 |
} |
} |
275 |
|
|
276 |
/* Decrypt data using RC4 */ |
/* Decrypt data using RC4 */ |
277 |
static void |
void |
278 |
sec_decrypt(uint8 * data, int length) |
sec_decrypt(uint8 * data, int length) |
279 |
{ |
{ |
280 |
static int use_count; |
if (sec_decrypt_use_count == 4096) |
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|
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if (use_count == 4096) |
|
281 |
{ |
{ |
282 |
sec_update(sec_decrypt_key, sec_decrypt_update_key); |
sec_update(sec_decrypt_key, sec_decrypt_update_key); |
283 |
RC4_set_key(&rc4_decrypt_key, rc4_key_len, sec_decrypt_key); |
RC4_set_key(&rc4_decrypt_key, rc4_key_len, sec_decrypt_key); |
284 |
use_count = 0; |
sec_decrypt_use_count = 0; |
285 |
} |
} |
286 |
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|
287 |
RC4(&rc4_decrypt_key, length, data, data); |
RC4(&rc4_decrypt_key, length, data, data); |
288 |
use_count++; |
sec_decrypt_use_count++; |
289 |
} |
} |
290 |
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291 |
static void |
static void |
304 |
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305 |
/* Perform an RSA public key encryption operation */ |
/* Perform an RSA public key encryption operation */ |
306 |
static void |
static void |
307 |
sec_rsa_encrypt(uint8 * out, uint8 * in, int len, uint8 * modulus, uint8 * exponent) |
sec_rsa_encrypt(uint8 * out, uint8 * in, int len, uint32 modulus_size, uint8 * modulus, |
308 |
|
uint8 * exponent) |
309 |
{ |
{ |
310 |
BN_CTX *ctx; |
BN_CTX *ctx; |
311 |
BIGNUM mod, exp, x, y; |
BIGNUM mod, exp, x, y; |
312 |
uint8 inr[SEC_MODULUS_SIZE]; |
uint8 inr[SEC_MAX_MODULUS_SIZE]; |
313 |
int outlen; |
int outlen; |
314 |
|
|
315 |
reverse(modulus, SEC_MODULUS_SIZE); |
reverse(modulus, modulus_size); |
316 |
reverse(exponent, SEC_EXPONENT_SIZE); |
reverse(exponent, SEC_EXPONENT_SIZE); |
317 |
memcpy(inr, in, len); |
memcpy(inr, in, len); |
318 |
reverse(inr, len); |
reverse(inr, len); |
323 |
BN_init(&x); |
BN_init(&x); |
324 |
BN_init(&y); |
BN_init(&y); |
325 |
|
|
326 |
BN_bin2bn(modulus, SEC_MODULUS_SIZE, &mod); |
BN_bin2bn(modulus, modulus_size, &mod); |
327 |
BN_bin2bn(exponent, SEC_EXPONENT_SIZE, &exp); |
BN_bin2bn(exponent, SEC_EXPONENT_SIZE, &exp); |
328 |
BN_bin2bn(inr, len, &x); |
BN_bin2bn(inr, len, &x); |
329 |
BN_mod_exp(&y, &x, &exp, &mod, ctx); |
BN_mod_exp(&y, &x, &exp, &mod, ctx); |
330 |
outlen = BN_bn2bin(&y, out); |
outlen = BN_bn2bin(&y, out); |
331 |
reverse(out, outlen); |
reverse(out, outlen); |
332 |
if (outlen < SEC_MODULUS_SIZE) |
if (outlen < modulus_size) |
333 |
memset(out + outlen, 0, SEC_MODULUS_SIZE - outlen); |
memset(out + outlen, 0, modulus_size - outlen); |
334 |
|
|
335 |
BN_free(&y); |
BN_free(&y); |
336 |
BN_clear_free(&x); |
BN_clear_free(&x); |
346 |
int hdrlen; |
int hdrlen; |
347 |
STREAM s; |
STREAM s; |
348 |
|
|
349 |
if (!licence_issued) |
if (!g_licence_issued) |
350 |
hdrlen = (flags & SEC_ENCRYPT) ? 12 : 4; |
hdrlen = (flags & SEC_ENCRYPT) ? 12 : 4; |
351 |
else |
else |
352 |
hdrlen = (flags & SEC_ENCRYPT) ? 12 : 0; |
hdrlen = (flags & SEC_ENCRYPT) ? 12 : 0; |
356 |
return s; |
return s; |
357 |
} |
} |
358 |
|
|
359 |
/* Transmit secure transport packet */ |
/* Transmit secure transport packet over specified channel */ |
360 |
void |
void |
361 |
sec_send(STREAM s, uint32 flags) |
sec_send_to_channel(STREAM s, uint32 flags, uint16 channel) |
362 |
{ |
{ |
363 |
int datalen; |
int datalen; |
364 |
|
|
365 |
s_pop_layer(s, sec_hdr); |
s_pop_layer(s, sec_hdr); |
366 |
if (!licence_issued || (flags & SEC_ENCRYPT)) |
if (!g_licence_issued || (flags & SEC_ENCRYPT)) |
367 |
out_uint32_le(s, flags); |
out_uint32_le(s, flags); |
368 |
|
|
369 |
if (flags & SEC_ENCRYPT) |
if (flags & SEC_ENCRYPT) |
380 |
sec_encrypt(s->p + 8, datalen); |
sec_encrypt(s->p + 8, datalen); |
381 |
} |
} |
382 |
|
|
383 |
mcs_send(s); |
mcs_send_to_channel(s, channel); |
384 |
} |
} |
385 |
|
|
386 |
|
/* Transmit secure transport packet */ |
387 |
|
|
388 |
|
void |
389 |
|
sec_send(STREAM s, uint32 flags) |
390 |
|
{ |
391 |
|
sec_send_to_channel(s, flags, MCS_GLOBAL_CHANNEL); |
392 |
|
} |
393 |
|
|
394 |
|
|
395 |
/* Transfer the client random to the server */ |
/* Transfer the client random to the server */ |
396 |
static void |
static void |
397 |
sec_establish_key(void) |
sec_establish_key(void) |
398 |
{ |
{ |
399 |
uint32 length = SEC_MODULUS_SIZE + SEC_PADDING_SIZE; |
uint32 length = server_public_key_len + SEC_PADDING_SIZE; |
400 |
uint32 flags = SEC_CLIENT_RANDOM; |
uint32 flags = SEC_CLIENT_RANDOM; |
401 |
STREAM s; |
STREAM s; |
402 |
|
|
403 |
s = sec_init(flags, 76); |
s = sec_init(flags, length + 4); |
404 |
|
|
405 |
out_uint32_le(s, length); |
out_uint32_le(s, length); |
406 |
out_uint8p(s, sec_crypted_random, SEC_MODULUS_SIZE); |
out_uint8p(s, sec_crypted_random, server_public_key_len); |
407 |
out_uint8s(s, SEC_PADDING_SIZE); |
out_uint8s(s, SEC_PADDING_SIZE); |
408 |
|
|
409 |
s_mark_end(s); |
s_mark_end(s); |
414 |
static void |
static void |
415 |
sec_out_mcs_data(STREAM s) |
sec_out_mcs_data(STREAM s) |
416 |
{ |
{ |
417 |
int hostlen = 2 * strlen(hostname); |
int hostlen = 2 * strlen(g_hostname); |
418 |
|
int length = 158 + 76 + 12 + 4; |
419 |
|
unsigned int i; |
420 |
|
|
421 |
|
if (g_num_channels > 0) |
422 |
|
length += g_num_channels * 12 + 8; |
423 |
|
|
424 |
if (hostlen > 30) |
if (hostlen > 30) |
425 |
hostlen = 30; |
hostlen = 30; |
426 |
|
|
427 |
out_uint16_be(s, 5); /* unknown */ |
/* Generic Conference Control (T.124) ConferenceCreateRequest */ |
428 |
|
out_uint16_be(s, 5); |
429 |
out_uint16_be(s, 0x14); |
out_uint16_be(s, 0x14); |
430 |
out_uint8(s, 0x7c); |
out_uint8(s, 0x7c); |
431 |
out_uint16_be(s, 1); |
out_uint16_be(s, 1); |
432 |
|
|
433 |
out_uint16_be(s, (158 | 0x8000)); /* remaining length */ |
out_uint16_be(s, (length | 0x8000)); /* remaining length */ |
434 |
|
|
435 |
out_uint16_be(s, 8); /* length? */ |
out_uint16_be(s, 8); /* length? */ |
436 |
out_uint16_be(s, 16); |
out_uint16_be(s, 16); |
438 |
out_uint16_le(s, 0xc001); |
out_uint16_le(s, 0xc001); |
439 |
out_uint8(s, 0); |
out_uint8(s, 0); |
440 |
|
|
441 |
out_uint32_le(s, 0x61637544); /* "Duca" ?! */ |
out_uint32_le(s, 0x61637544); /* OEM ID: "Duca", as in Ducati. */ |
442 |
out_uint16_be(s, (144 | 0x8000)); /* remaining length */ |
out_uint16_be(s, ((length - 14) | 0x8000)); /* remaining length */ |
443 |
|
|
444 |
/* Client information */ |
/* Client information */ |
445 |
out_uint16_le(s, SEC_TAG_CLI_INFO); |
out_uint16_le(s, SEC_TAG_CLI_INFO); |
446 |
out_uint16_le(s, 136); /* length */ |
out_uint16_le(s, 212); /* length */ |
447 |
out_uint16_le(s, 1); |
out_uint16_le(s, g_use_rdp5 ? 4 : 1); /* RDP version. 1 == RDP4, 4 == RDP5. */ |
448 |
out_uint16_le(s, 8); |
out_uint16_le(s, 8); |
449 |
out_uint16_le(s, width); |
out_uint16_le(s, g_width); |
450 |
out_uint16_le(s, height); |
out_uint16_le(s, g_height); |
451 |
out_uint16_le(s, 0xca01); |
out_uint16_le(s, 0xca01); |
452 |
out_uint16_le(s, 0xaa03); |
out_uint16_le(s, 0xaa03); |
453 |
out_uint32_le(s, keylayout); |
out_uint32_le(s, g_keylayout); |
454 |
out_uint32_le(s, 419); /* client build? we are 419 compatible :-) */ |
out_uint32_le(s, 2600); /* Client build. We are now 2600 compatible :-) */ |
455 |
|
|
456 |
/* Unicode name of client, padded to 32 bytes */ |
/* Unicode name of client, padded to 32 bytes */ |
457 |
rdp_out_unistr(s, hostname, hostlen); |
rdp_out_unistr(s, g_hostname, hostlen); |
458 |
out_uint8s(s, 30 - hostlen); |
out_uint8s(s, 30 - hostlen); |
459 |
|
|
460 |
out_uint32_le(s, 4); |
/* See |
461 |
out_uint32(s, 0); |
http://msdn.microsoft.com/library/default.asp?url=/library/en-us/wceddk40/html/cxtsksupportingremotedesktopprotocol.asp */ |
462 |
out_uint32_le(s, 12); |
out_uint32_le(s, g_keyboard_type); |
463 |
|
out_uint32_le(s, g_keyboard_subtype); |
464 |
|
out_uint32_le(s, g_keyboard_functionkeys); |
465 |
out_uint8s(s, 64); /* reserved? 4 + 12 doublewords */ |
out_uint8s(s, 64); /* reserved? 4 + 12 doublewords */ |
466 |
|
out_uint16_le(s, 0xca01); /* colour depth? */ |
467 |
|
out_uint16_le(s, 1); |
468 |
|
|
469 |
switch (server_bpp) |
out_uint32(s, 0); |
470 |
{ |
out_uint8(s, g_server_depth); |
471 |
case 8: |
out_uint16_le(s, 0x0700); |
472 |
out_uint16_le(s, 0xca01); |
out_uint8(s, 0); |
473 |
break; |
out_uint32_le(s, 1); |
474 |
case 15: |
out_uint8s(s, 64); /* End of client info */ |
475 |
out_uint16_le(s, 0xca02); |
|
476 |
break; |
out_uint16_le(s, SEC_TAG_CLI_4); |
477 |
case 16: |
out_uint16_le(s, 12); |
478 |
out_uint16_le(s, 0xca03); |
out_uint32_le(s, g_console_session ? 0xb : 9); |
479 |
break; |
out_uint32(s, 0); |
|
case 24: |
|
|
out_uint16_le(s, 0xca04); |
|
|
break; |
|
|
} |
|
|
out_uint16(s, 0); |
|
480 |
|
|
481 |
/* Client encryption settings */ |
/* Client encryption settings */ |
482 |
out_uint16_le(s, SEC_TAG_CLI_CRYPT); |
out_uint16_le(s, SEC_TAG_CLI_CRYPT); |
483 |
out_uint16_le(s, 8); /* length */ |
out_uint16_le(s, 12); /* length */ |
484 |
out_uint32_le(s, encryption ? 0x3 : 0); /* encryption supported, 128-bit supported */ |
out_uint32_le(s, g_encryption ? 0x3 : 0); /* encryption supported, 128-bit supported */ |
485 |
|
out_uint32(s, 0); /* Unknown */ |
486 |
|
|
487 |
|
DEBUG_RDP5(("g_num_channels is %d\n", g_num_channels)); |
488 |
|
if (g_num_channels > 0) |
489 |
|
{ |
490 |
|
out_uint16_le(s, SEC_TAG_CLI_CHANNELS); |
491 |
|
out_uint16_le(s, g_num_channels * 12 + 8); /* length */ |
492 |
|
out_uint32_le(s, g_num_channels); /* number of virtual channels */ |
493 |
|
for (i = 0; i < g_num_channels; i++) |
494 |
|
{ |
495 |
|
DEBUG_RDP5(("Requesting channel %s\n", g_channels[i].name)); |
496 |
|
out_uint8a(s, g_channels[i].name, 8); |
497 |
|
out_uint32_be(s, g_channels[i].flags); |
498 |
|
} |
499 |
|
} |
500 |
|
|
501 |
s_mark_end(s); |
s_mark_end(s); |
502 |
} |
} |
503 |
|
|
515 |
} |
} |
516 |
|
|
517 |
in_uint32_le(s, modulus_len); |
in_uint32_le(s, modulus_len); |
518 |
if (modulus_len != SEC_MODULUS_SIZE + SEC_PADDING_SIZE) |
modulus_len -= SEC_PADDING_SIZE; |
519 |
|
if ((modulus_len < 64) || (modulus_len > SEC_MAX_MODULUS_SIZE)) |
520 |
{ |
{ |
521 |
error("modulus len 0x%x\n", modulus_len); |
error("Bad server public key size (%u bits)\n", modulus_len * 8); |
522 |
return False; |
return False; |
523 |
} |
} |
524 |
|
|
525 |
in_uint8s(s, 8); /* modulus_bits, unknown */ |
in_uint8s(s, 8); /* modulus_bits, unknown */ |
526 |
in_uint8p(s, *exponent, SEC_EXPONENT_SIZE); |
in_uint8p(s, *exponent, SEC_EXPONENT_SIZE); |
527 |
in_uint8p(s, *modulus, SEC_MODULUS_SIZE); |
in_uint8p(s, *modulus, modulus_len); |
528 |
in_uint8s(s, SEC_PADDING_SIZE); |
in_uint8s(s, SEC_PADDING_SIZE); |
529 |
|
server_public_key_len = modulus_len; |
530 |
|
|
531 |
return s_check(s); |
return s_check(s); |
532 |
} |
} |
533 |
|
|
534 |
|
static BOOL |
535 |
|
sec_parse_x509_key(X509 * cert) |
536 |
|
{ |
537 |
|
EVP_PKEY *epk = NULL; |
538 |
|
/* By some reason, Microsoft sets the OID of the Public RSA key to |
539 |
|
the oid for "MD5 with RSA Encryption" instead of "RSA Encryption" |
540 |
|
|
541 |
|
Kudos to Richard Levitte for the following (. intiutive .) |
542 |
|
lines of code that resets the OID and let's us extract the key. */ |
543 |
|
if (OBJ_obj2nid(cert->cert_info->key->algor->algorithm) == NID_md5WithRSAEncryption) |
544 |
|
{ |
545 |
|
DEBUG_RDP5(("Re-setting algorithm type to RSA in server certificate\n")); |
546 |
|
ASN1_OBJECT_free(cert->cert_info->key->algor->algorithm); |
547 |
|
cert->cert_info->key->algor->algorithm = OBJ_nid2obj(NID_rsaEncryption); |
548 |
|
} |
549 |
|
epk = X509_get_pubkey(cert); |
550 |
|
if (NULL == epk) |
551 |
|
{ |
552 |
|
error("Failed to extract public key from certificate\n"); |
553 |
|
return False; |
554 |
|
} |
555 |
|
|
556 |
|
server_public_key = RSAPublicKey_dup((RSA *) epk->pkey.ptr); |
557 |
|
EVP_PKEY_free(epk); |
558 |
|
|
559 |
|
server_public_key_len = RSA_size(server_public_key); |
560 |
|
if ((server_public_key_len < 64) || (server_public_key_len > SEC_MAX_MODULUS_SIZE)) |
561 |
|
{ |
562 |
|
error("Bad server public key size (%u bits)\n", server_public_key_len * 8); |
563 |
|
return False; |
564 |
|
} |
565 |
|
|
566 |
|
return True; |
567 |
|
} |
568 |
|
|
569 |
|
|
570 |
/* Parse a crypto information structure */ |
/* Parse a crypto information structure */ |
571 |
static BOOL |
static BOOL |
572 |
sec_parse_crypt_info(STREAM s, uint32 * rc4_key_size, |
sec_parse_crypt_info(STREAM s, uint32 * rc4_key_size, |
573 |
uint8 ** server_random, uint8 ** modulus, uint8 ** exponent) |
uint8 ** server_random, uint8 ** modulus, uint8 ** exponent) |
574 |
{ |
{ |
575 |
uint32 crypt_level, random_len, rsa_info_len; |
uint32 crypt_level, random_len, rsa_info_len; |
576 |
|
uint32 cacert_len, cert_len, flags; |
577 |
|
X509 *cacert, *server_cert; |
578 |
uint16 tag, length; |
uint16 tag, length; |
579 |
uint8 *next_tag, *end; |
uint8 *next_tag, *end; |
580 |
|
|
581 |
in_uint32_le(s, *rc4_key_size); /* 1 = 40-bit, 2 = 128-bit */ |
in_uint32_le(s, *rc4_key_size); /* 1 = 40-bit, 2 = 128-bit */ |
582 |
in_uint32_le(s, crypt_level); /* 1 = low, 2 = medium, 3 = high */ |
in_uint32_le(s, crypt_level); /* 1 = low, 2 = medium, 3 = high */ |
583 |
if (crypt_level == 0) /* no encryptation */ |
if (crypt_level == 0) /* no encryption */ |
584 |
return False; |
return False; |
585 |
in_uint32_le(s, random_len); |
in_uint32_le(s, random_len); |
586 |
in_uint32_le(s, rsa_info_len); |
in_uint32_le(s, rsa_info_len); |
587 |
|
|
588 |
if (random_len != SEC_RANDOM_SIZE) |
if (random_len != SEC_RANDOM_SIZE) |
589 |
{ |
{ |
590 |
error("random len %d\n", random_len); |
error("random len %d, expected %d\n", random_len, SEC_RANDOM_SIZE); |
591 |
return False; |
return False; |
592 |
} |
} |
593 |
|
|
598 |
if (end > s->end) |
if (end > s->end) |
599 |
return False; |
return False; |
600 |
|
|
601 |
in_uint8s(s, 12); /* unknown */ |
in_uint32_le(s, flags); /* 1 = RDP4-style, 0x80000002 = X.509 */ |
602 |
|
if (flags & 1) |
603 |
|
{ |
604 |
|
DEBUG_RDP5(("We're going for the RDP4-style encryption\n")); |
605 |
|
in_uint8s(s, 8); /* unknown */ |
606 |
|
|
607 |
|
while (s->p < end) |
608 |
|
{ |
609 |
|
in_uint16_le(s, tag); |
610 |
|
in_uint16_le(s, length); |
611 |
|
|
612 |
|
next_tag = s->p + length; |
613 |
|
|
614 |
|
switch (tag) |
615 |
|
{ |
616 |
|
case SEC_TAG_PUBKEY: |
617 |
|
if (!sec_parse_public_key(s, modulus, exponent)) |
618 |
|
return False; |
619 |
|
DEBUG_RDP5(("Got Public key, RDP4-style\n")); |
620 |
|
|
621 |
|
break; |
622 |
|
|
623 |
|
case SEC_TAG_KEYSIG: |
624 |
|
/* Is this a Microsoft key that we just got? */ |
625 |
|
/* Care factor: zero! */ |
626 |
|
/* Actually, it would probably be a good idea to check if the public key is signed with this key, and then store this |
627 |
|
key as a known key of the hostname. This would prevent some MITM-attacks. */ |
628 |
|
break; |
629 |
|
|
630 |
|
default: |
631 |
|
unimpl("crypt tag 0x%x\n", tag); |
632 |
|
} |
633 |
|
|
634 |
while (s->p < end) |
s->p = next_tag; |
635 |
|
} |
636 |
|
} |
637 |
|
else |
638 |
{ |
{ |
639 |
in_uint16_le(s, tag); |
uint32 certcount; |
|
in_uint16_le(s, length); |
|
640 |
|
|
641 |
next_tag = s->p + length; |
DEBUG_RDP5(("We're going for the RDP5-style encryption\n")); |
642 |
|
in_uint32_le(s, certcount); /* Number of certificates */ |
643 |
|
|
644 |
switch (tag) |
if (certcount < 2) |
645 |
{ |
{ |
646 |
case SEC_TAG_PUBKEY: |
error("Server didn't send enough X509 certificates\n"); |
647 |
if (!sec_parse_public_key(s, modulus, exponent)) |
return False; |
648 |
return False; |
} |
649 |
|
|
650 |
break; |
for (; certcount > 2; certcount--) |
651 |
|
{ /* ignore all the certificates between the root and the signing CA */ |
652 |
|
uint32 ignorelen; |
653 |
|
X509 *ignorecert; |
654 |
|
|
655 |
|
DEBUG_RDP5(("Ignored certs left: %d\n", certcount)); |
656 |
|
|
657 |
|
in_uint32_le(s, ignorelen); |
658 |
|
DEBUG_RDP5(("Ignored Certificate length is %d\n", ignorelen)); |
659 |
|
ignorecert = |
660 |
|
d2i_X509(NULL, (D2I_X509_CONST unsigned char **) &(s->p), |
661 |
|
ignorelen); |
662 |
|
|
663 |
|
if (ignorecert == NULL) |
664 |
|
{ /* XXX: error out? */ |
665 |
|
DEBUG_RDP5(("got a bad cert: this will probably screw up the rest of the communication\n")); |
666 |
|
} |
667 |
|
|
668 |
case SEC_TAG_KEYSIG: |
#ifdef WITH_DEBUG_RDP5 |
669 |
/* Is this a Microsoft key that we just got? */ |
DEBUG_RDP5(("cert #%d (ignored):\n", certcount)); |
670 |
/* Care factor: zero! */ |
X509_print_fp(stdout, ignorecert); |
671 |
break; |
#endif |
672 |
|
} |
673 |
|
|
674 |
default: |
/* Do da funky X.509 stuffy |
675 |
unimpl("crypt tag 0x%x\n", tag); |
|
676 |
|
"How did I find out about this? I looked up and saw a |
677 |
|
bright light and when I came to I had a scar on my forehead |
678 |
|
and knew about X.500" |
679 |
|
- Peter Gutman in a early version of |
680 |
|
http://www.cs.auckland.ac.nz/~pgut001/pubs/x509guide.txt |
681 |
|
*/ |
682 |
|
|
683 |
|
in_uint32_le(s, cacert_len); |
684 |
|
DEBUG_RDP5(("CA Certificate length is %d\n", cacert_len)); |
685 |
|
cacert = d2i_X509(NULL, (D2I_X509_CONST unsigned char **) &(s->p), cacert_len); |
686 |
|
/* Note: We don't need to move s->p here - d2i_X509 is |
687 |
|
"kind" enough to do it for us */ |
688 |
|
if (NULL == cacert) |
689 |
|
{ |
690 |
|
error("Couldn't load CA Certificate from server\n"); |
691 |
|
return False; |
692 |
} |
} |
693 |
|
|
694 |
s->p = next_tag; |
/* Currently, we don't use the CA Certificate. |
695 |
} |
FIXME: |
696 |
|
*) Verify the server certificate (server_cert) with the |
697 |
|
CA certificate. |
698 |
|
*) Store the CA Certificate with the hostname of the |
699 |
|
server we are connecting to as key, and compare it |
700 |
|
when we connect the next time, in order to prevent |
701 |
|
MITM-attacks. |
702 |
|
*/ |
703 |
|
|
704 |
|
X509_free(cacert); |
705 |
|
|
706 |
|
in_uint32_le(s, cert_len); |
707 |
|
DEBUG_RDP5(("Certificate length is %d\n", cert_len)); |
708 |
|
server_cert = d2i_X509(NULL, (D2I_X509_CONST unsigned char **) &(s->p), cert_len); |
709 |
|
if (NULL == server_cert) |
710 |
|
{ |
711 |
|
error("Couldn't load Certificate from server\n"); |
712 |
|
return False; |
713 |
|
} |
714 |
|
|
715 |
|
in_uint8s(s, 16); /* Padding */ |
716 |
|
|
717 |
|
/* Note: Verifying the server certificate must be done here, |
718 |
|
before sec_parse_public_key since we'll have to apply |
719 |
|
serious violence to the key after this */ |
720 |
|
|
721 |
|
if (!sec_parse_x509_key(server_cert)) |
722 |
|
{ |
723 |
|
DEBUG_RDP5(("Didn't parse X509 correctly\n")); |
724 |
|
X509_free(server_cert); |
725 |
|
return False; |
726 |
|
} |
727 |
|
X509_free(server_cert); |
728 |
|
return True; /* There's some garbage here we don't care about */ |
729 |
|
} |
730 |
return s_check_end(s); |
return s_check_end(s); |
731 |
} |
} |
732 |
|
|
734 |
static void |
static void |
735 |
sec_process_crypt_info(STREAM s) |
sec_process_crypt_info(STREAM s) |
736 |
{ |
{ |
737 |
uint8 *server_random, *modulus, *exponent; |
uint8 *server_random = NULL, *modulus = NULL, *exponent = NULL; |
738 |
uint8 client_random[SEC_RANDOM_SIZE]; |
uint8 client_random[SEC_RANDOM_SIZE]; |
739 |
uint32 rc4_key_size; |
uint32 rc4_key_size; |
740 |
|
|
741 |
if (!sec_parse_crypt_info(s, &rc4_key_size, &server_random, &modulus, &exponent)) |
if (!sec_parse_crypt_info(s, &rc4_key_size, &server_random, &modulus, &exponent)) |
742 |
|
{ |
743 |
|
DEBUG(("Failed to parse crypt info\n")); |
744 |
return; |
return; |
745 |
|
} |
746 |
|
|
747 |
/* Generate a client random, and hence determine encryption keys */ |
DEBUG(("Generating client random\n")); |
748 |
generate_random(client_random); |
generate_random(client_random); |
749 |
sec_rsa_encrypt(sec_crypted_random, client_random, SEC_RANDOM_SIZE, modulus, exponent); |
|
750 |
|
if (NULL != server_public_key) |
751 |
|
{ /* Which means we should use |
752 |
|
RDP5-style encryption */ |
753 |
|
uint8 inr[SEC_MAX_MODULUS_SIZE]; |
754 |
|
uint32 padding_len = server_public_key_len - SEC_RANDOM_SIZE; |
755 |
|
|
756 |
|
/* This is what the MS client do: */ |
757 |
|
memset(inr, 0, padding_len); |
758 |
|
/* *ARIGL!* Plaintext attack, anyone? |
759 |
|
I tried doing: |
760 |
|
generate_random(inr); |
761 |
|
..but that generates connection errors now and then (yes, |
762 |
|
"now and then". Something like 0 to 3 attempts needed before a |
763 |
|
successful connection. Nice. Not! |
764 |
|
*/ |
765 |
|
memcpy(inr + padding_len, client_random, SEC_RANDOM_SIZE); |
766 |
|
reverse(inr + padding_len, SEC_RANDOM_SIZE); |
767 |
|
|
768 |
|
RSA_public_encrypt(server_public_key_len, |
769 |
|
inr, sec_crypted_random, server_public_key, RSA_NO_PADDING); |
770 |
|
|
771 |
|
reverse(sec_crypted_random, server_public_key_len); |
772 |
|
|
773 |
|
RSA_free(server_public_key); |
774 |
|
server_public_key = NULL; |
775 |
|
} |
776 |
|
else |
777 |
|
{ /* RDP4-style encryption */ |
778 |
|
sec_rsa_encrypt(sec_crypted_random, |
779 |
|
client_random, SEC_RANDOM_SIZE, server_public_key_len, modulus, |
780 |
|
exponent); |
781 |
|
} |
782 |
sec_generate_keys(client_random, server_random, rc4_key_size); |
sec_generate_keys(client_random, server_random, rc4_key_size); |
783 |
} |
} |
784 |
|
|
785 |
/* Process connect response data blob */ |
|
786 |
|
/* Process SRV_INFO, find RDP version supported by server */ |
787 |
static void |
static void |
788 |
|
sec_process_srv_info(STREAM s) |
789 |
|
{ |
790 |
|
in_uint16_le(s, g_server_rdp_version); |
791 |
|
DEBUG_RDP5(("Server RDP version is %d\n", g_server_rdp_version)); |
792 |
|
if (1 == g_server_rdp_version) |
793 |
|
{ |
794 |
|
g_use_rdp5 = 0; |
795 |
|
g_server_depth = 8; |
796 |
|
} |
797 |
|
} |
798 |
|
|
799 |
|
|
800 |
|
/* Process connect response data blob */ |
801 |
|
void |
802 |
sec_process_mcs_data(STREAM s) |
sec_process_mcs_data(STREAM s) |
803 |
{ |
{ |
804 |
uint16 tag, length; |
uint16 tag, length; |
805 |
uint8 *next_tag; |
uint8 *next_tag; |
806 |
uint8 len; |
uint8 len; |
807 |
|
|
808 |
in_uint8s(s, 21); /* header */ |
in_uint8s(s, 21); /* header (T.124 ConferenceCreateResponse) */ |
809 |
in_uint8(s, len); |
in_uint8(s, len); |
810 |
if (len & 0x80) |
if (len & 0x80) |
811 |
in_uint8(s, len); |
in_uint8(s, len); |
823 |
switch (tag) |
switch (tag) |
824 |
{ |
{ |
825 |
case SEC_TAG_SRV_INFO: |
case SEC_TAG_SRV_INFO: |
826 |
case SEC_TAG_SRV_3: |
sec_process_srv_info(s); |
827 |
break; |
break; |
828 |
|
|
829 |
case SEC_TAG_SRV_CRYPT: |
case SEC_TAG_SRV_CRYPT: |
830 |
sec_process_crypt_info(s); |
sec_process_crypt_info(s); |
831 |
break; |
break; |
832 |
|
|
833 |
|
case SEC_TAG_SRV_CHANNELS: |
834 |
|
/* FIXME: We should parse this information and |
835 |
|
use it to map RDP5 channels to MCS |
836 |
|
channels */ |
837 |
|
break; |
838 |
|
|
839 |
default: |
default: |
840 |
unimpl("response tag 0x%x\n", tag); |
unimpl("response tag 0x%x\n", tag); |
841 |
} |
} |
846 |
|
|
847 |
/* Receive secure transport packet */ |
/* Receive secure transport packet */ |
848 |
STREAM |
STREAM |
849 |
sec_recv(void) |
sec_recv(uint8 * rdpver) |
850 |
{ |
{ |
851 |
uint32 sec_flags; |
uint32 sec_flags; |
852 |
|
uint16 channel; |
853 |
STREAM s; |
STREAM s; |
854 |
|
|
855 |
while ((s = mcs_recv()) != NULL) |
while ((s = mcs_recv(&channel, rdpver)) != NULL) |
856 |
{ |
{ |
857 |
if (encryption || !licence_issued) |
if (rdpver != NULL) |
858 |
|
{ |
859 |
|
if (*rdpver != 3) |
860 |
|
{ |
861 |
|
if (*rdpver & 0x80) |
862 |
|
{ |
863 |
|
in_uint8s(s, 8); /* signature */ |
864 |
|
sec_decrypt(s->p, s->end - s->p); |
865 |
|
} |
866 |
|
return s; |
867 |
|
} |
868 |
|
} |
869 |
|
if (g_encryption || !g_licence_issued) |
870 |
{ |
{ |
871 |
in_uint32_le(s, sec_flags); |
in_uint32_le(s, sec_flags); |
872 |
|
|
873 |
|
if (sec_flags & SEC_ENCRYPT) |
874 |
|
{ |
875 |
|
in_uint8s(s, 8); /* signature */ |
876 |
|
sec_decrypt(s->p, s->end - s->p); |
877 |
|
} |
878 |
|
|
879 |
if (sec_flags & SEC_LICENCE_NEG) |
if (sec_flags & SEC_LICENCE_NEG) |
880 |
{ |
{ |
881 |
licence_process(s); |
licence_process(s); |
882 |
continue; |
continue; |
883 |
} |
} |
884 |
|
|
885 |
if (sec_flags & SEC_ENCRYPT) |
if (sec_flags & 0x0400) /* SEC_REDIRECT_ENCRYPT */ |
886 |
{ |
{ |
887 |
|
uint8 swapbyte; |
888 |
|
|
889 |
in_uint8s(s, 8); /* signature */ |
in_uint8s(s, 8); /* signature */ |
890 |
sec_decrypt(s->p, s->end - s->p); |
sec_decrypt(s->p, s->end - s->p); |
891 |
|
|
892 |
|
/* Check for a redirect packet, starts with 00 04 */ |
893 |
|
if (s->p[0] == 0 && s->p[1] == 4) |
894 |
|
{ |
895 |
|
/* for some reason the PDU and the length seem to be swapped. |
896 |
|
This isn't good, but we're going to do a byte for byte |
897 |
|
swap. So the first foure value appear as: 00 04 XX YY, |
898 |
|
where XX YY is the little endian length. We're going to |
899 |
|
use 04 00 as the PDU type, so after our swap this will look |
900 |
|
like: XX YY 04 00 */ |
901 |
|
swapbyte = s->p[0]; |
902 |
|
s->p[0] = s->p[2]; |
903 |
|
s->p[2] = swapbyte; |
904 |
|
|
905 |
|
swapbyte = s->p[1]; |
906 |
|
s->p[1] = s->p[3]; |
907 |
|
s->p[3] = swapbyte; |
908 |
|
|
909 |
|
swapbyte = s->p[2]; |
910 |
|
s->p[2] = s->p[3]; |
911 |
|
s->p[3] = swapbyte; |
912 |
|
} |
913 |
|
#ifdef WITH_DEBUG |
914 |
|
/* warning! this debug statement will show passwords in the clear! */ |
915 |
|
hexdump(s->p, s->end - s->p); |
916 |
|
#endif |
917 |
} |
} |
918 |
|
|
919 |
|
} |
920 |
|
|
921 |
|
if (channel != MCS_GLOBAL_CHANNEL) |
922 |
|
{ |
923 |
|
channel_process(s, channel); |
924 |
|
*rdpver = 0xff; |
925 |
|
return s; |
926 |
} |
} |
927 |
|
|
928 |
return s; |
return s; |
933 |
|
|
934 |
/* Establish a secure connection */ |
/* Establish a secure connection */ |
935 |
BOOL |
BOOL |
936 |
sec_connect(char *server) |
sec_connect(char *server, char *username) |
937 |
{ |
{ |
938 |
struct stream mcs_data; |
struct stream mcs_data; |
939 |
|
|
940 |
/* We exchange some RDP data during the MCS-Connect */ |
/* We exchange some RDP data during the MCS-Connect */ |
941 |
mcs_data.size = 512; |
mcs_data.size = 512; |
942 |
mcs_data.p = mcs_data.data = xmalloc(mcs_data.size); |
mcs_data.p = mcs_data.data = (uint8 *) xmalloc(mcs_data.size); |
943 |
sec_out_mcs_data(&mcs_data); |
sec_out_mcs_data(&mcs_data); |
944 |
|
|
945 |
if (!mcs_connect(server, &mcs_data)) |
if (!mcs_connect(server, &mcs_data, username)) |
946 |
return False; |
return False; |
947 |
|
|
948 |
sec_process_mcs_data(&mcs_data); |
/* sec_process_mcs_data(&mcs_data); */ |
949 |
if (encryption) |
if (g_encryption) |
950 |
|
sec_establish_key(); |
951 |
|
xfree(mcs_data.data); |
952 |
|
return True; |
953 |
|
} |
954 |
|
|
955 |
|
/* Establish a secure connection */ |
956 |
|
BOOL |
957 |
|
sec_reconnect(char *server) |
958 |
|
{ |
959 |
|
struct stream mcs_data; |
960 |
|
|
961 |
|
/* We exchange some RDP data during the MCS-Connect */ |
962 |
|
mcs_data.size = 512; |
963 |
|
mcs_data.p = mcs_data.data = (uint8 *) xmalloc(mcs_data.size); |
964 |
|
sec_out_mcs_data(&mcs_data); |
965 |
|
|
966 |
|
if (!mcs_reconnect(server, &mcs_data)) |
967 |
|
return False; |
968 |
|
|
969 |
|
/* sec_process_mcs_data(&mcs_data); */ |
970 |
|
if (g_encryption) |
971 |
sec_establish_key(); |
sec_establish_key(); |
972 |
xfree(mcs_data.data); |
xfree(mcs_data.data); |
973 |
return True; |
return True; |
979 |
{ |
{ |
980 |
mcs_disconnect(); |
mcs_disconnect(); |
981 |
} |
} |
982 |
|
|
983 |
|
/* reset the state of the sec layer */ |
984 |
|
void |
985 |
|
sec_reset_state(void) |
986 |
|
{ |
987 |
|
g_server_rdp_version = 0; |
988 |
|
sec_encrypt_use_count = 0; |
989 |
|
sec_decrypt_use_count = 0; |
990 |
|
mcs_reset_state(); |
991 |
|
} |