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 1999-2001 |
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 |
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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 |
#else |
#include <openssl/x509v3.h> |
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#include "crypto/rc4.h" |
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#include "crypto/md5.h" |
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#include "crypto/sha.h" |
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#include "crypto/bn.h" |
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#endif |
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28 |
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29 |
extern char hostname[16]; |
extern char g_hostname[16]; |
30 |
extern int width; |
extern int g_width; |
31 |
extern int height; |
extern int g_height; |
32 |
extern int keylayout; |
extern unsigned int g_keylayout; |
33 |
extern BOOL encryption; |
extern int g_keyboard_type; |
34 |
extern BOOL licence_issued; |
extern int g_keyboard_subtype; |
35 |
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extern int g_keyboard_functionkeys; |
36 |
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extern BOOL g_encryption; |
37 |
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extern BOOL g_licence_issued; |
38 |
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extern BOOL g_use_rdp5; |
39 |
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extern BOOL g_console_session; |
40 |
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extern int g_server_depth; |
41 |
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extern uint16 mcs_userid; |
42 |
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extern VCHANNEL g_channels[]; |
43 |
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extern unsigned int g_num_channels; |
44 |
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45 |
static int rc4_key_len; |
static int rc4_key_len; |
46 |
static RC4_KEY rc4_decrypt_key; |
static RC4_KEY rc4_decrypt_key; |
47 |
static RC4_KEY rc4_encrypt_key; |
static RC4_KEY rc4_encrypt_key; |
48 |
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static RSA *server_public_key; |
49 |
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static uint32 server_public_key_len; |
50 |
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51 |
static uint8 sec_sign_key[16]; |
static uint8 sec_sign_key[16]; |
52 |
static uint8 sec_decrypt_key[16]; |
static uint8 sec_decrypt_key[16]; |
53 |
static uint8 sec_encrypt_key[16]; |
static uint8 sec_encrypt_key[16]; |
54 |
static uint8 sec_decrypt_update_key[16]; |
static uint8 sec_decrypt_update_key[16]; |
55 |
static uint8 sec_encrypt_update_key[16]; |
static uint8 sec_encrypt_update_key[16]; |
56 |
static uint8 sec_crypted_random[SEC_MODULUS_SIZE]; |
static uint8 sec_crypted_random[SEC_MAX_MODULUS_SIZE]; |
57 |
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58 |
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uint16 g_server_rdp_version = 0; |
59 |
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60 |
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/* These values must be available to reset state - Session Directory */ |
61 |
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static int sec_encrypt_use_count = 0; |
62 |
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static int sec_decrypt_use_count = 0; |
63 |
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64 |
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/* |
65 |
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* I believe this is based on SSLv3 with the following differences: |
66 |
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* MAC algorithm (5.2.3.1) uses only 32-bit length in place of seq_num/type/length fields |
67 |
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* MAC algorithm uses SHA1 and MD5 for the two hash functions instead of one or other |
68 |
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* key_block algorithm (6.2.2) uses 'X', 'YY', 'ZZZ' instead of 'A', 'BB', 'CCC' |
69 |
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* key_block partitioning is different (16 bytes each: MAC secret, decrypt key, encrypt key) |
70 |
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* encryption/decryption keys updated every 4096 packets |
71 |
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* See http://wp.netscape.com/eng/ssl3/draft302.txt |
72 |
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*/ |
73 |
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74 |
/* |
/* |
75 |
* 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. |
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76 |
* Both SHA1 and MD5 algorithms are used. |
* Both SHA1 and MD5 algorithms are used. |
77 |
*/ |
*/ |
78 |
void |
void |
103 |
} |
} |
104 |
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105 |
/* |
/* |
106 |
* 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. |
|
107 |
*/ |
*/ |
108 |
void |
void |
109 |
sec_hash_16(uint8 * out, uint8 * in, uint8 * salt1, uint8 * salt2) |
sec_hash_16(uint8 * out, uint8 * in, uint8 * salt1, uint8 * salt2) |
126 |
key[2] = 0x9e; |
key[2] = 0x9e; |
127 |
} |
} |
128 |
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129 |
/* Generate a session key and RC4 keys, given client and server randoms */ |
/* Generate encryption keys given client and server randoms */ |
130 |
static void |
static void |
131 |
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) |
132 |
{ |
{ |
133 |
uint8 session_key[48]; |
uint8 pre_master_secret[48]; |
134 |
uint8 temp_hash[48]; |
uint8 master_secret[48]; |
135 |
uint8 input[48]; |
uint8 key_block[48]; |
136 |
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|
137 |
/* Construct input data to hash */ |
/* Construct pre-master secret */ |
138 |
memcpy(input, client_key, 24); |
memcpy(pre_master_secret, client_random, 24); |
139 |
memcpy(input + 24, server_key, 24); |
memcpy(pre_master_secret + 24, server_random, 24); |
140 |
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141 |
/* Generate session key - two rounds of sec_hash_48 */ |
/* Generate master secret and then key material */ |
142 |
sec_hash_48(temp_hash, input, client_key, server_key, 65); |
sec_hash_48(master_secret, pre_master_secret, client_random, server_random, 'A'); |
143 |
sec_hash_48(session_key, temp_hash, client_key, server_key, 88); |
sec_hash_48(key_block, master_secret, client_random, server_random, 'X'); |
144 |
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|
145 |
/* Store first 16 bytes of session key, for generating signatures */ |
/* First 16 bytes of key material is MAC secret */ |
146 |
memcpy(sec_sign_key, session_key, 16); |
memcpy(sec_sign_key, key_block, 16); |
147 |
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|
148 |
/* Generate RC4 keys */ |
/* Generate export keys from next two blocks of 16 bytes */ |
149 |
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); |
150 |
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); |
151 |
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152 |
if (rc4_key_size == 1) |
if (rc4_key_size == 1) |
153 |
{ |
{ |
159 |
} |
} |
160 |
else |
else |
161 |
{ |
{ |
162 |
DEBUG(("128-bit encryption enabled\n")); |
DEBUG(("rc_4_key_size == %d, 128-bit encryption enabled\n", rc4_key_size)); |
163 |
rc4_key_len = 16; |
rc4_key_len = 16; |
164 |
} |
} |
165 |
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196 |
buffer[3] = (value >> 24) & 0xff; |
buffer[3] = (value >> 24) & 0xff; |
197 |
} |
} |
198 |
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199 |
/* 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 */ |
200 |
void |
void |
201 |
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) |
202 |
{ |
{ |
224 |
memcpy(signature, md5sig, siglen); |
memcpy(signature, md5sig, siglen); |
225 |
} |
} |
226 |
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|
227 |
/* Update an encryption key - similar to the signing process */ |
/* Update an encryption key */ |
228 |
static void |
static void |
229 |
sec_update(uint8 * key, uint8 * update_key) |
sec_update(uint8 * key, uint8 * update_key) |
230 |
{ |
{ |
256 |
static void |
static void |
257 |
sec_encrypt(uint8 * data, int length) |
sec_encrypt(uint8 * data, int length) |
258 |
{ |
{ |
259 |
static int use_count; |
if (sec_encrypt_use_count == 4096) |
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if (use_count == 4096) |
|
260 |
{ |
{ |
261 |
sec_update(sec_encrypt_key, sec_encrypt_update_key); |
sec_update(sec_encrypt_key, sec_encrypt_update_key); |
262 |
RC4_set_key(&rc4_encrypt_key, rc4_key_len, sec_encrypt_key); |
RC4_set_key(&rc4_encrypt_key, rc4_key_len, sec_encrypt_key); |
263 |
use_count = 0; |
sec_encrypt_use_count = 0; |
264 |
} |
} |
265 |
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|
266 |
RC4(&rc4_encrypt_key, length, data, data); |
RC4(&rc4_encrypt_key, length, data, data); |
267 |
use_count++; |
sec_encrypt_use_count++; |
268 |
} |
} |
269 |
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|
270 |
/* Decrypt data using RC4 */ |
/* Decrypt data using RC4 */ |
271 |
static void |
void |
272 |
sec_decrypt(uint8 * data, int length) |
sec_decrypt(uint8 * data, int length) |
273 |
{ |
{ |
274 |
static int use_count; |
if (sec_decrypt_use_count == 4096) |
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if (use_count == 4096) |
|
275 |
{ |
{ |
276 |
sec_update(sec_decrypt_key, sec_decrypt_update_key); |
sec_update(sec_decrypt_key, sec_decrypt_update_key); |
277 |
RC4_set_key(&rc4_decrypt_key, rc4_key_len, sec_decrypt_key); |
RC4_set_key(&rc4_decrypt_key, rc4_key_len, sec_decrypt_key); |
278 |
use_count = 0; |
sec_decrypt_use_count = 0; |
279 |
} |
} |
280 |
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|
281 |
RC4(&rc4_decrypt_key, length, data, data); |
RC4(&rc4_decrypt_key, length, data, data); |
282 |
use_count++; |
sec_decrypt_use_count++; |
283 |
} |
} |
284 |
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285 |
static void |
static void |
298 |
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299 |
/* Perform an RSA public key encryption operation */ |
/* Perform an RSA public key encryption operation */ |
300 |
static void |
static void |
301 |
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, |
302 |
|
uint8 * exponent) |
303 |
{ |
{ |
304 |
BN_CTX ctx; |
BN_CTX *ctx; |
305 |
BIGNUM mod, exp, x, y; |
BIGNUM mod, exp, x, y; |
306 |
uint8 inr[SEC_MODULUS_SIZE]; |
uint8 inr[SEC_MAX_MODULUS_SIZE]; |
307 |
int outlen; |
int outlen; |
308 |
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|
309 |
reverse(modulus, SEC_MODULUS_SIZE); |
reverse(modulus, modulus_size); |
310 |
reverse(exponent, SEC_EXPONENT_SIZE); |
reverse(exponent, SEC_EXPONENT_SIZE); |
311 |
memcpy(inr, in, len); |
memcpy(inr, in, len); |
312 |
reverse(inr, len); |
reverse(inr, len); |
313 |
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|
314 |
BN_CTX_init(&ctx); |
ctx = BN_CTX_new(); |
315 |
BN_init(&mod); |
BN_init(&mod); |
316 |
BN_init(&exp); |
BN_init(&exp); |
317 |
BN_init(&x); |
BN_init(&x); |
318 |
BN_init(&y); |
BN_init(&y); |
319 |
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|
320 |
BN_bin2bn(modulus, SEC_MODULUS_SIZE, &mod); |
BN_bin2bn(modulus, modulus_size, &mod); |
321 |
BN_bin2bn(exponent, SEC_EXPONENT_SIZE, &exp); |
BN_bin2bn(exponent, SEC_EXPONENT_SIZE, &exp); |
322 |
BN_bin2bn(inr, len, &x); |
BN_bin2bn(inr, len, &x); |
323 |
BN_mod_exp(&y, &x, &exp, &mod, &ctx); |
BN_mod_exp(&y, &x, &exp, &mod, ctx); |
324 |
outlen = BN_bn2bin(&y, out); |
outlen = BN_bn2bin(&y, out); |
325 |
reverse(out, outlen); |
reverse(out, outlen); |
326 |
if (outlen < SEC_MODULUS_SIZE) |
if (outlen < modulus_size) |
327 |
memset(out + outlen, 0, SEC_MODULUS_SIZE - outlen); |
memset(out + outlen, 0, modulus_size - outlen); |
328 |
|
|
329 |
BN_free(&y); |
BN_free(&y); |
330 |
BN_clear_free(&x); |
BN_clear_free(&x); |
331 |
BN_free(&exp); |
BN_free(&exp); |
332 |
BN_free(&mod); |
BN_free(&mod); |
333 |
BN_CTX_free(&ctx); |
BN_CTX_free(ctx); |
334 |
} |
} |
335 |
|
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336 |
/* Initialise secure transport packet */ |
/* Initialise secure transport packet */ |
340 |
int hdrlen; |
int hdrlen; |
341 |
STREAM s; |
STREAM s; |
342 |
|
|
343 |
if (!licence_issued) |
if (!g_licence_issued) |
344 |
hdrlen = (flags & SEC_ENCRYPT) ? 12 : 4; |
hdrlen = (flags & SEC_ENCRYPT) ? 12 : 4; |
345 |
else |
else |
346 |
hdrlen = (flags & SEC_ENCRYPT) ? 12 : 0; |
hdrlen = (flags & SEC_ENCRYPT) ? 12 : 0; |
350 |
return s; |
return s; |
351 |
} |
} |
352 |
|
|
353 |
/* Transmit secure transport packet */ |
/* Transmit secure transport packet over specified channel */ |
354 |
void |
void |
355 |
sec_send(STREAM s, uint32 flags) |
sec_send_to_channel(STREAM s, uint32 flags, uint16 channel) |
356 |
{ |
{ |
357 |
int datalen; |
int datalen; |
358 |
|
|
359 |
s_pop_layer(s, sec_hdr); |
s_pop_layer(s, sec_hdr); |
360 |
if (!licence_issued || (flags & SEC_ENCRYPT)) |
if (!g_licence_issued || (flags & SEC_ENCRYPT)) |
361 |
out_uint32_le(s, flags); |
out_uint32_le(s, flags); |
362 |
|
|
363 |
if (flags & SEC_ENCRYPT) |
if (flags & SEC_ENCRYPT) |
374 |
sec_encrypt(s->p + 8, datalen); |
sec_encrypt(s->p + 8, datalen); |
375 |
} |
} |
376 |
|
|
377 |
mcs_send(s); |
mcs_send_to_channel(s, channel); |
378 |
} |
} |
379 |
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380 |
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/* Transmit secure transport packet */ |
381 |
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382 |
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void |
383 |
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sec_send(STREAM s, uint32 flags) |
384 |
|
{ |
385 |
|
sec_send_to_channel(s, flags, MCS_GLOBAL_CHANNEL); |
386 |
|
} |
387 |
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388 |
|
|
389 |
/* Transfer the client random to the server */ |
/* Transfer the client random to the server */ |
390 |
static void |
static void |
391 |
sec_establish_key() |
sec_establish_key(void) |
392 |
{ |
{ |
393 |
uint32 length = SEC_MODULUS_SIZE + SEC_PADDING_SIZE; |
uint32 length = server_public_key_len + SEC_PADDING_SIZE; |
394 |
uint32 flags = SEC_CLIENT_RANDOM; |
uint32 flags = SEC_CLIENT_RANDOM; |
395 |
STREAM s; |
STREAM s; |
396 |
|
|
397 |
s = sec_init(flags, 76); |
s = sec_init(flags, length + 4); |
398 |
|
|
399 |
out_uint32_le(s, length); |
out_uint32_le(s, length); |
400 |
out_uint8p(s, sec_crypted_random, SEC_MODULUS_SIZE); |
out_uint8p(s, sec_crypted_random, server_public_key_len); |
401 |
out_uint8s(s, SEC_PADDING_SIZE); |
out_uint8s(s, SEC_PADDING_SIZE); |
402 |
|
|
403 |
s_mark_end(s); |
s_mark_end(s); |
408 |
static void |
static void |
409 |
sec_out_mcs_data(STREAM s) |
sec_out_mcs_data(STREAM s) |
410 |
{ |
{ |
411 |
int hostlen = 2 * strlen(hostname); |
int hostlen = 2 * strlen(g_hostname); |
412 |
|
int length = 158 + 76 + 12 + 4; |
413 |
|
unsigned int i; |
414 |
|
|
415 |
|
if (g_num_channels > 0) |
416 |
|
length += g_num_channels * 12 + 8; |
417 |
|
|
418 |
if (hostlen > 30) |
if (hostlen > 30) |
419 |
hostlen = 30; |
hostlen = 30; |
420 |
|
|
421 |
out_uint16_be(s, 5); /* unknown */ |
/* Generic Conference Control (T.124) ConferenceCreateRequest */ |
422 |
|
out_uint16_be(s, 5); |
423 |
out_uint16_be(s, 0x14); |
out_uint16_be(s, 0x14); |
424 |
out_uint8(s, 0x7c); |
out_uint8(s, 0x7c); |
425 |
out_uint16_be(s, 1); |
out_uint16_be(s, 1); |
426 |
|
|
427 |
out_uint16_be(s, (158 | 0x8000)); /* remaining length */ |
out_uint16_be(s, (length | 0x8000)); /* remaining length */ |
428 |
|
|
429 |
out_uint16_be(s, 8); /* length? */ |
out_uint16_be(s, 8); /* length? */ |
430 |
out_uint16_be(s, 16); |
out_uint16_be(s, 16); |
432 |
out_uint16_le(s, 0xc001); |
out_uint16_le(s, 0xc001); |
433 |
out_uint8(s, 0); |
out_uint8(s, 0); |
434 |
|
|
435 |
out_uint32_le(s, 0x61637544); /* "Duca" ?! */ |
out_uint32_le(s, 0x61637544); /* OEM ID: "Duca", as in Ducati. */ |
436 |
out_uint16_be(s, (144 | 0x8000)); /* remaining length */ |
out_uint16_be(s, ((length - 14) | 0x8000)); /* remaining length */ |
437 |
|
|
438 |
/* Client information */ |
/* Client information */ |
439 |
out_uint16_le(s, SEC_TAG_CLI_INFO); |
out_uint16_le(s, SEC_TAG_CLI_INFO); |
440 |
out_uint16_le(s, 136); /* length */ |
out_uint16_le(s, 212); /* length */ |
441 |
out_uint16_le(s, 1); |
out_uint16_le(s, g_use_rdp5 ? 4 : 1); /* RDP version. 1 == RDP4, 4 == RDP5. */ |
442 |
out_uint16_le(s, 8); |
out_uint16_le(s, 8); |
443 |
out_uint16_le(s, width); |
out_uint16_le(s, g_width); |
444 |
out_uint16_le(s, height); |
out_uint16_le(s, g_height); |
445 |
out_uint16_le(s, 0xca01); |
out_uint16_le(s, 0xca01); |
446 |
out_uint16_le(s, 0xaa03); |
out_uint16_le(s, 0xaa03); |
447 |
out_uint32_le(s, keylayout); |
out_uint32_le(s, g_keylayout); |
448 |
out_uint32_le(s, 419); /* client build? we are 419 compatible :-) */ |
out_uint32_le(s, 2600); /* Client build. We are now 2600 compatible :-) */ |
449 |
|
|
450 |
/* Unicode name of client, padded to 32 bytes */ |
/* Unicode name of client, padded to 32 bytes */ |
451 |
rdp_out_unistr(s, hostname, hostlen); |
rdp_out_unistr(s, g_hostname, hostlen); |
452 |
out_uint8s(s, 30 - hostlen); |
out_uint8s(s, 30 - hostlen); |
453 |
|
|
454 |
out_uint32_le(s, 4); |
/* See |
455 |
out_uint32(s, 0); |
http://msdn.microsoft.com/library/default.asp?url=/library/en-us/wceddk40/html/cxtsksupportingremotedesktopprotocol.asp */ |
456 |
out_uint32_le(s, 12); |
out_uint32_le(s, g_keyboard_type); |
457 |
|
out_uint32_le(s, g_keyboard_subtype); |
458 |
|
out_uint32_le(s, g_keyboard_functionkeys); |
459 |
out_uint8s(s, 64); /* reserved? 4 + 12 doublewords */ |
out_uint8s(s, 64); /* reserved? 4 + 12 doublewords */ |
460 |
|
out_uint16_le(s, 0xca01); /* colour depth? */ |
461 |
|
out_uint16_le(s, 1); |
462 |
|
|
463 |
out_uint16(s, 0xca01); |
out_uint32(s, 0); |
464 |
out_uint16(s, 0); |
out_uint8(s, g_server_depth); |
465 |
|
out_uint16_le(s, 0x0700); |
466 |
|
out_uint8(s, 0); |
467 |
|
out_uint32_le(s, 1); |
468 |
|
out_uint8s(s, 64); /* End of client info */ |
469 |
|
|
470 |
|
out_uint16_le(s, SEC_TAG_CLI_4); |
471 |
|
out_uint16_le(s, 12); |
472 |
|
out_uint32_le(s, g_console_session ? 0xb : 9); |
473 |
|
out_uint32(s, 0); |
474 |
|
|
475 |
/* Client encryption settings */ |
/* Client encryption settings */ |
476 |
out_uint16_le(s, SEC_TAG_CLI_CRYPT); |
out_uint16_le(s, SEC_TAG_CLI_CRYPT); |
477 |
out_uint16(s, 8); /* length */ |
out_uint16_le(s, 12); /* length */ |
478 |
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 */ |
479 |
|
out_uint32(s, 0); /* Unknown */ |
480 |
|
|
481 |
|
DEBUG_RDP5(("g_num_channels is %d\n", g_num_channels)); |
482 |
|
if (g_num_channels > 0) |
483 |
|
{ |
484 |
|
out_uint16_le(s, SEC_TAG_CLI_CHANNELS); |
485 |
|
out_uint16_le(s, g_num_channels * 12 + 8); /* length */ |
486 |
|
out_uint32_le(s, g_num_channels); /* number of virtual channels */ |
487 |
|
for (i = 0; i < g_num_channels; i++) |
488 |
|
{ |
489 |
|
DEBUG_RDP5(("Requesting channel %s\n", g_channels[i].name)); |
490 |
|
out_uint8a(s, g_channels[i].name, 8); |
491 |
|
out_uint32_be(s, g_channels[i].flags); |
492 |
|
} |
493 |
|
} |
494 |
|
|
495 |
s_mark_end(s); |
s_mark_end(s); |
496 |
} |
} |
497 |
|
|
509 |
} |
} |
510 |
|
|
511 |
in_uint32_le(s, modulus_len); |
in_uint32_le(s, modulus_len); |
512 |
if (modulus_len != SEC_MODULUS_SIZE + SEC_PADDING_SIZE) |
modulus_len -= SEC_PADDING_SIZE; |
513 |
|
if ((modulus_len < 64) || (modulus_len > SEC_MAX_MODULUS_SIZE)) |
514 |
{ |
{ |
515 |
error("modulus len 0x%x\n", modulus_len); |
error("Bad server public key size (%u bits)\n", modulus_len * 8); |
516 |
return False; |
return False; |
517 |
} |
} |
518 |
|
|
519 |
in_uint8s(s, 8); /* modulus_bits, unknown */ |
in_uint8s(s, 8); /* modulus_bits, unknown */ |
520 |
in_uint8p(s, *exponent, SEC_EXPONENT_SIZE); |
in_uint8p(s, *exponent, SEC_EXPONENT_SIZE); |
521 |
in_uint8p(s, *modulus, SEC_MODULUS_SIZE); |
in_uint8p(s, *modulus, modulus_len); |
522 |
in_uint8s(s, SEC_PADDING_SIZE); |
in_uint8s(s, SEC_PADDING_SIZE); |
523 |
|
server_public_key_len = modulus_len; |
524 |
|
|
525 |
return s_check(s); |
return s_check(s); |
526 |
} |
} |
527 |
|
|
528 |
|
static BOOL |
529 |
|
sec_parse_x509_key(X509 * cert) |
530 |
|
{ |
531 |
|
EVP_PKEY *epk = NULL; |
532 |
|
/* By some reason, Microsoft sets the OID of the Public RSA key to |
533 |
|
the oid for "MD5 with RSA Encryption" instead of "RSA Encryption" |
534 |
|
|
535 |
|
Kudos to Richard Levitte for the following (. intiutive .) |
536 |
|
lines of code that resets the OID and let's us extract the key. */ |
537 |
|
if (OBJ_obj2nid(cert->cert_info->key->algor->algorithm) == NID_md5WithRSAEncryption) |
538 |
|
{ |
539 |
|
DEBUG_RDP5(("Re-setting algorithm type to RSA in server certificate\n")); |
540 |
|
ASN1_OBJECT_free(cert->cert_info->key->algor->algorithm); |
541 |
|
cert->cert_info->key->algor->algorithm = OBJ_nid2obj(NID_rsaEncryption); |
542 |
|
} |
543 |
|
epk = X509_get_pubkey(cert); |
544 |
|
if (NULL == epk) |
545 |
|
{ |
546 |
|
error("Failed to extract public key from certificate\n"); |
547 |
|
return False; |
548 |
|
} |
549 |
|
|
550 |
|
server_public_key = RSAPublicKey_dup((RSA *) epk->pkey.ptr); |
551 |
|
EVP_PKEY_free(epk); |
552 |
|
|
553 |
|
server_public_key_len = RSA_size(server_public_key); |
554 |
|
if ((server_public_key_len < 64) || (server_public_key_len > SEC_MAX_MODULUS_SIZE)) |
555 |
|
{ |
556 |
|
error("Bad server public key size (%u bits)\n", server_public_key_len * 8); |
557 |
|
return False; |
558 |
|
} |
559 |
|
|
560 |
|
return True; |
561 |
|
} |
562 |
|
|
563 |
|
|
564 |
/* Parse a crypto information structure */ |
/* Parse a crypto information structure */ |
565 |
static BOOL |
static BOOL |
566 |
sec_parse_crypt_info(STREAM s, uint32 * rc4_key_size, |
sec_parse_crypt_info(STREAM s, uint32 * rc4_key_size, |
567 |
uint8 ** server_random, uint8 ** modulus, uint8 ** exponent) |
uint8 ** server_random, uint8 ** modulus, uint8 ** exponent) |
568 |
{ |
{ |
569 |
uint32 crypt_level, random_len, rsa_info_len; |
uint32 crypt_level, random_len, rsa_info_len; |
570 |
|
uint32 cacert_len, cert_len, flags; |
571 |
|
X509 *cacert, *server_cert; |
572 |
uint16 tag, length; |
uint16 tag, length; |
573 |
uint8 *next_tag, *end; |
uint8 *next_tag, *end; |
574 |
|
|
575 |
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 */ |
576 |
in_uint32_le(s, crypt_level); /* 1 = low, 2 = medium, 3 = high */ |
in_uint32_le(s, crypt_level); /* 1 = low, 2 = medium, 3 = high */ |
577 |
if (crypt_level == 0) /* no encryptation */ |
if (crypt_level == 0) /* no encryption */ |
578 |
return False; |
return False; |
579 |
in_uint32_le(s, random_len); |
in_uint32_le(s, random_len); |
580 |
in_uint32_le(s, rsa_info_len); |
in_uint32_le(s, rsa_info_len); |
581 |
|
|
582 |
if (random_len != SEC_RANDOM_SIZE) |
if (random_len != SEC_RANDOM_SIZE) |
583 |
{ |
{ |
584 |
error("random len %d\n", random_len); |
error("random len %d, expected %d\n", random_len, SEC_RANDOM_SIZE); |
585 |
return False; |
return False; |
586 |
} |
} |
587 |
|
|
592 |
if (end > s->end) |
if (end > s->end) |
593 |
return False; |
return False; |
594 |
|
|
595 |
in_uint8s(s, 12); /* unknown */ |
in_uint32_le(s, flags); /* 1 = RDP4-style, 0x80000002 = X.509 */ |
596 |
|
if (flags & 1) |
597 |
|
{ |
598 |
|
DEBUG_RDP5(("We're going for the RDP4-style encryption\n")); |
599 |
|
in_uint8s(s, 8); /* unknown */ |
600 |
|
|
601 |
|
while (s->p < end) |
602 |
|
{ |
603 |
|
in_uint16_le(s, tag); |
604 |
|
in_uint16_le(s, length); |
605 |
|
|
606 |
|
next_tag = s->p + length; |
607 |
|
|
608 |
|
switch (tag) |
609 |
|
{ |
610 |
|
case SEC_TAG_PUBKEY: |
611 |
|
if (!sec_parse_public_key(s, modulus, exponent)) |
612 |
|
return False; |
613 |
|
DEBUG_RDP5(("Got Public key, RDP4-style\n")); |
614 |
|
|
615 |
|
break; |
616 |
|
|
617 |
|
case SEC_TAG_KEYSIG: |
618 |
|
/* Is this a Microsoft key that we just got? */ |
619 |
|
/* Care factor: zero! */ |
620 |
|
/* Actually, it would probably be a good idea to check if the public key is signed with this key, and then store this |
621 |
|
key as a known key of the hostname. This would prevent some MITM-attacks. */ |
622 |
|
break; |
623 |
|
|
624 |
|
default: |
625 |
|
unimpl("crypt tag 0x%x\n", tag); |
626 |
|
} |
627 |
|
|
628 |
while (s->p < end) |
s->p = next_tag; |
629 |
|
} |
630 |
|
} |
631 |
|
else |
632 |
{ |
{ |
633 |
in_uint16_le(s, tag); |
uint32 certcount; |
|
in_uint16_le(s, length); |
|
634 |
|
|
635 |
next_tag = s->p + length; |
DEBUG_RDP5(("We're going for the RDP5-style encryption\n")); |
636 |
|
in_uint32_le(s, certcount); /* Number of certificates */ |
637 |
|
|
638 |
switch (tag) |
if (certcount < 2) |
639 |
{ |
{ |
640 |
case SEC_TAG_PUBKEY: |
error("Server didn't send enough X509 certificates\n"); |
641 |
if (!sec_parse_public_key(s, modulus, exponent)) |
return False; |
642 |
return False; |
} |
643 |
|
|
644 |
break; |
for (; certcount > 2; certcount--) |
645 |
|
{ /* ignore all the certificates between the root and the signing CA */ |
646 |
|
uint32 ignorelen; |
647 |
|
X509 *ignorecert; |
648 |
|
|
649 |
|
DEBUG_RDP5(("Ignored certs left: %d\n", certcount)); |
650 |
|
|
651 |
|
in_uint32_le(s, ignorelen); |
652 |
|
DEBUG_RDP5(("Ignored Certificate length is %d\n", ignorelen)); |
653 |
|
ignorecert = d2i_X509(NULL, &(s->p), ignorelen); |
654 |
|
|
655 |
|
if (ignorecert == NULL) |
656 |
|
{ /* XXX: error out? */ |
657 |
|
DEBUG_RDP5(("got a bad cert: this will probably screw up the rest of the communication\n")); |
658 |
|
} |
659 |
|
|
660 |
case SEC_TAG_KEYSIG: |
#ifdef WITH_DEBUG_RDP5 |
661 |
/* Is this a Microsoft key that we just got? */ |
DEBUG_RDP5(("cert #%d (ignored):\n", certcount)); |
662 |
/* Care factor: zero! */ |
X509_print_fp(stdout, ignorecert); |
663 |
break; |
#endif |
664 |
|
} |
665 |
|
|
666 |
default: |
/* Do da funky X.509 stuffy |
667 |
unimpl("crypt tag 0x%x\n", tag); |
|
668 |
|
"How did I find out about this? I looked up and saw a |
669 |
|
bright light and when I came to I had a scar on my forehead |
670 |
|
and knew about X.500" |
671 |
|
- Peter Gutman in a early version of |
672 |
|
http://www.cs.auckland.ac.nz/~pgut001/pubs/x509guide.txt |
673 |
|
*/ |
674 |
|
|
675 |
|
in_uint32_le(s, cacert_len); |
676 |
|
DEBUG_RDP5(("CA Certificate length is %d\n", cacert_len)); |
677 |
|
cacert = d2i_X509(NULL, &(s->p), cacert_len); |
678 |
|
/* Note: We don't need to move s->p here - d2i_X509 is |
679 |
|
"kind" enough to do it for us */ |
680 |
|
if (NULL == cacert) |
681 |
|
{ |
682 |
|
error("Couldn't load CA Certificate from server\n"); |
683 |
|
return False; |
684 |
} |
} |
685 |
|
|
686 |
s->p = next_tag; |
/* Currently, we don't use the CA Certificate. |
687 |
} |
FIXME: |
688 |
|
*) Verify the server certificate (server_cert) with the |
689 |
|
CA certificate. |
690 |
|
*) Store the CA Certificate with the hostname of the |
691 |
|
server we are connecting to as key, and compare it |
692 |
|
when we connect the next time, in order to prevent |
693 |
|
MITM-attacks. |
694 |
|
*/ |
695 |
|
|
696 |
|
X509_free(cacert); |
697 |
|
|
698 |
|
in_uint32_le(s, cert_len); |
699 |
|
DEBUG_RDP5(("Certificate length is %d\n", cert_len)); |
700 |
|
server_cert = d2i_X509(NULL, &(s->p), cert_len); |
701 |
|
if (NULL == server_cert) |
702 |
|
{ |
703 |
|
error("Couldn't load Certificate from server\n"); |
704 |
|
return False; |
705 |
|
} |
706 |
|
|
707 |
|
in_uint8s(s, 16); /* Padding */ |
708 |
|
|
709 |
|
/* Note: Verifying the server certificate must be done here, |
710 |
|
before sec_parse_public_key since we'll have to apply |
711 |
|
serious violence to the key after this */ |
712 |
|
|
713 |
|
if (!sec_parse_x509_key(server_cert)) |
714 |
|
{ |
715 |
|
DEBUG_RDP5(("Didn't parse X509 correctly\n")); |
716 |
|
X509_free(server_cert); |
717 |
|
return False; |
718 |
|
} |
719 |
|
X509_free(server_cert); |
720 |
|
return True; /* There's some garbage here we don't care about */ |
721 |
|
} |
722 |
return s_check_end(s); |
return s_check_end(s); |
723 |
} |
} |
724 |
|
|
731 |
uint32 rc4_key_size; |
uint32 rc4_key_size; |
732 |
|
|
733 |
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)) |
734 |
|
{ |
735 |
|
DEBUG(("Failed to parse crypt info\n")); |
736 |
return; |
return; |
737 |
|
} |
738 |
|
|
739 |
/* Generate a client random, and hence determine encryption keys */ |
DEBUG(("Generating client random\n")); |
740 |
generate_random(client_random); |
generate_random(client_random); |
741 |
sec_rsa_encrypt(sec_crypted_random, client_random, SEC_RANDOM_SIZE, modulus, exponent); |
|
742 |
|
if (NULL != server_public_key) |
743 |
|
{ /* Which means we should use |
744 |
|
RDP5-style encryption */ |
745 |
|
uint8 inr[SEC_MAX_MODULUS_SIZE]; |
746 |
|
uint32 padding_len = server_public_key_len - SEC_RANDOM_SIZE; |
747 |
|
|
748 |
|
/* This is what the MS client do: */ |
749 |
|
memset(inr, 0, padding_len); |
750 |
|
/* *ARIGL!* Plaintext attack, anyone? |
751 |
|
I tried doing: |
752 |
|
generate_random(inr); |
753 |
|
..but that generates connection errors now and then (yes, |
754 |
|
"now and then". Something like 0 to 3 attempts needed before a |
755 |
|
successful connection. Nice. Not! |
756 |
|
*/ |
757 |
|
memcpy(inr + padding_len, client_random, SEC_RANDOM_SIZE); |
758 |
|
reverse(inr + padding_len, SEC_RANDOM_SIZE); |
759 |
|
|
760 |
|
RSA_public_encrypt(server_public_key_len, |
761 |
|
inr, sec_crypted_random, server_public_key, RSA_NO_PADDING); |
762 |
|
|
763 |
|
reverse(sec_crypted_random, server_public_key_len); |
764 |
|
|
765 |
|
RSA_free(server_public_key); |
766 |
|
server_public_key = NULL; |
767 |
|
} |
768 |
|
else |
769 |
|
{ /* RDP4-style encryption */ |
770 |
|
sec_rsa_encrypt(sec_crypted_random, |
771 |
|
client_random, SEC_RANDOM_SIZE, server_public_key_len, modulus, |
772 |
|
exponent); |
773 |
|
} |
774 |
sec_generate_keys(client_random, server_random, rc4_key_size); |
sec_generate_keys(client_random, server_random, rc4_key_size); |
775 |
} |
} |
776 |
|
|
777 |
/* Process connect response data blob */ |
|
778 |
|
/* Process SRV_INFO, find RDP version supported by server */ |
779 |
static void |
static void |
780 |
|
sec_process_srv_info(STREAM s) |
781 |
|
{ |
782 |
|
in_uint16_le(s, g_server_rdp_version); |
783 |
|
DEBUG_RDP5(("Server RDP version is %d\n", g_server_rdp_version)); |
784 |
|
if (1 == g_server_rdp_version) |
785 |
|
{ |
786 |
|
g_use_rdp5 = 0; |
787 |
|
g_server_depth = 8; |
788 |
|
} |
789 |
|
} |
790 |
|
|
791 |
|
|
792 |
|
/* Process connect response data blob */ |
793 |
|
void |
794 |
sec_process_mcs_data(STREAM s) |
sec_process_mcs_data(STREAM s) |
795 |
{ |
{ |
796 |
uint16 tag, length; |
uint16 tag, length; |
797 |
uint8 *next_tag; |
uint8 *next_tag; |
798 |
uint8 len; |
uint8 len; |
799 |
|
|
800 |
in_uint8s(s, 21); /* header */ |
in_uint8s(s, 21); /* header (T.124 ConferenceCreateResponse) */ |
801 |
in_uint8(s, len); |
in_uint8(s, len); |
802 |
if (len & 0x80) |
if (len & 0x80) |
803 |
in_uint8(s, len); |
in_uint8(s, len); |
815 |
switch (tag) |
switch (tag) |
816 |
{ |
{ |
817 |
case SEC_TAG_SRV_INFO: |
case SEC_TAG_SRV_INFO: |
818 |
case SEC_TAG_SRV_3: |
sec_process_srv_info(s); |
819 |
break; |
break; |
820 |
|
|
821 |
case SEC_TAG_SRV_CRYPT: |
case SEC_TAG_SRV_CRYPT: |
822 |
sec_process_crypt_info(s); |
sec_process_crypt_info(s); |
823 |
break; |
break; |
824 |
|
|
825 |
|
case SEC_TAG_SRV_CHANNELS: |
826 |
|
/* FIXME: We should parse this information and |
827 |
|
use it to map RDP5 channels to MCS |
828 |
|
channels */ |
829 |
|
break; |
830 |
|
|
831 |
default: |
default: |
832 |
unimpl("response tag 0x%x\n", tag); |
unimpl("response tag 0x%x\n", tag); |
833 |
} |
} |
838 |
|
|
839 |
/* Receive secure transport packet */ |
/* Receive secure transport packet */ |
840 |
STREAM |
STREAM |
841 |
sec_recv() |
sec_recv(uint8 * rdpver) |
842 |
{ |
{ |
843 |
uint32 sec_flags; |
uint32 sec_flags; |
844 |
|
uint16 channel; |
845 |
STREAM s; |
STREAM s; |
846 |
|
|
847 |
while ((s = mcs_recv()) != NULL) |
while ((s = mcs_recv(&channel, rdpver)) != NULL) |
848 |
{ |
{ |
849 |
if (encryption || !licence_issued) |
if (rdpver != NULL) |
850 |
|
{ |
851 |
|
if (*rdpver != 3) |
852 |
|
{ |
853 |
|
if (*rdpver & 0x80) |
854 |
|
{ |
855 |
|
in_uint8s(s, 8); /* signature */ |
856 |
|
sec_decrypt(s->p, s->end - s->p); |
857 |
|
} |
858 |
|
return s; |
859 |
|
} |
860 |
|
} |
861 |
|
if (g_encryption || !g_licence_issued) |
862 |
{ |
{ |
863 |
in_uint32_le(s, sec_flags); |
in_uint32_le(s, sec_flags); |
864 |
|
|
865 |
|
if (sec_flags & SEC_ENCRYPT) |
866 |
|
{ |
867 |
|
in_uint8s(s, 8); /* signature */ |
868 |
|
sec_decrypt(s->p, s->end - s->p); |
869 |
|
} |
870 |
|
|
871 |
if (sec_flags & SEC_LICENCE_NEG) |
if (sec_flags & SEC_LICENCE_NEG) |
872 |
{ |
{ |
873 |
licence_process(s); |
licence_process(s); |
874 |
continue; |
continue; |
875 |
} |
} |
876 |
|
|
877 |
if (sec_flags & SEC_ENCRYPT) |
if (sec_flags & 0x0400) /* SEC_REDIRECT_ENCRYPT */ |
878 |
{ |
{ |
879 |
|
uint8 swapbyte; |
880 |
|
|
881 |
in_uint8s(s, 8); /* signature */ |
in_uint8s(s, 8); /* signature */ |
882 |
sec_decrypt(s->p, s->end - s->p); |
sec_decrypt(s->p, s->end - s->p); |
883 |
|
|
884 |
|
/* Check for a redirect packet, starts with 00 04 */ |
885 |
|
if (s->p[0] == 0 && s->p[1] == 4) |
886 |
|
{ |
887 |
|
/* for some reason the PDU and the length seem to be swapped. |
888 |
|
This isn't good, but we're going to do a byte for byte |
889 |
|
swap. So the first foure value appear as: 00 04 XX YY, |
890 |
|
where XX YY is the little endian length. We're going to |
891 |
|
use 04 00 as the PDU type, so after our swap this will look |
892 |
|
like: XX YY 04 00 */ |
893 |
|
swapbyte = s->p[0]; |
894 |
|
s->p[0] = s->p[2]; |
895 |
|
s->p[2] = swapbyte; |
896 |
|
|
897 |
|
swapbyte = s->p[1]; |
898 |
|
s->p[1] = s->p[3]; |
899 |
|
s->p[3] = swapbyte; |
900 |
|
|
901 |
|
swapbyte = s->p[2]; |
902 |
|
s->p[2] = s->p[3]; |
903 |
|
s->p[3] = swapbyte; |
904 |
|
} |
905 |
|
#ifdef WITH_DEBUG |
906 |
|
/* warning! this debug statement will show passwords in the clear! */ |
907 |
|
hexdump(s->p, s->end - s->p); |
908 |
|
#endif |
909 |
} |
} |
910 |
|
|
911 |
|
} |
912 |
|
|
913 |
|
if (channel != MCS_GLOBAL_CHANNEL) |
914 |
|
{ |
915 |
|
channel_process(s, channel); |
916 |
|
*rdpver = 0xff; |
917 |
|
return s; |
918 |
} |
} |
919 |
|
|
920 |
return s; |
return s; |
925 |
|
|
926 |
/* Establish a secure connection */ |
/* Establish a secure connection */ |
927 |
BOOL |
BOOL |
928 |
sec_connect(char *server) |
sec_connect(char *server, char *username) |
929 |
|
{ |
930 |
|
struct stream mcs_data; |
931 |
|
|
932 |
|
/* We exchange some RDP data during the MCS-Connect */ |
933 |
|
mcs_data.size = 512; |
934 |
|
mcs_data.p = mcs_data.data = (uint8 *) xmalloc(mcs_data.size); |
935 |
|
sec_out_mcs_data(&mcs_data); |
936 |
|
|
937 |
|
if (!mcs_connect(server, &mcs_data, username)) |
938 |
|
return False; |
939 |
|
|
940 |
|
/* sec_process_mcs_data(&mcs_data); */ |
941 |
|
if (g_encryption) |
942 |
|
sec_establish_key(); |
943 |
|
xfree(mcs_data.data); |
944 |
|
return True; |
945 |
|
} |
946 |
|
|
947 |
|
/* Establish a secure connection */ |
948 |
|
BOOL |
949 |
|
sec_reconnect(char *server) |
950 |
{ |
{ |
951 |
struct stream mcs_data; |
struct stream mcs_data; |
952 |
|
|
953 |
/* We exchange some RDP data during the MCS-Connect */ |
/* We exchange some RDP data during the MCS-Connect */ |
954 |
mcs_data.size = 512; |
mcs_data.size = 512; |
955 |
mcs_data.p = mcs_data.data = xmalloc(mcs_data.size); |
mcs_data.p = mcs_data.data = (uint8 *) xmalloc(mcs_data.size); |
956 |
sec_out_mcs_data(&mcs_data); |
sec_out_mcs_data(&mcs_data); |
957 |
|
|
958 |
if (!mcs_connect(server, &mcs_data)) |
if (!mcs_reconnect(server, &mcs_data)) |
959 |
return False; |
return False; |
960 |
|
|
961 |
sec_process_mcs_data(&mcs_data); |
/* sec_process_mcs_data(&mcs_data); */ |
962 |
if (encryption) |
if (g_encryption) |
963 |
sec_establish_key(); |
sec_establish_key(); |
964 |
|
xfree(mcs_data.data); |
965 |
return True; |
return True; |
966 |
} |
} |
967 |
|
|
968 |
/* Disconnect a connection */ |
/* Disconnect a connection */ |
969 |
void |
void |
970 |
sec_disconnect() |
sec_disconnect(void) |
971 |
{ |
{ |
972 |
mcs_disconnect(); |
mcs_disconnect(); |
973 |
} |
} |
974 |
|
|
975 |
|
/* reset the state of the sec layer */ |
976 |
|
void |
977 |
|
sec_reset_state(void) |
978 |
|
{ |
979 |
|
g_server_rdp_version = 0; |
980 |
|
sec_encrypt_use_count = 0; |
981 |
|
sec_decrypt_use_count = 0; |
982 |
|
mcs_reset_state(); |
983 |
|
} |