1 |
/* |
2 |
rdesktop: A Remote Desktop Protocol client. |
3 |
Protocol services - RDP encryption and licensing |
4 |
Copyright (C) Matthew Chapman 1999-2001 |
5 |
|
6 |
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 |
8 |
the Free Software Foundation; either version 2 of the License, or |
9 |
(at your option) any later version. |
10 |
|
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This program is distributed in the hope that it will be useful, |
12 |
but WITHOUT ANY WARRANTY; without even the implied warranty of |
13 |
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
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GNU General Public License for more details. |
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|
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You should have received a copy of the GNU General Public License |
17 |
along with this program; if not, write to the Free Software |
18 |
Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. |
19 |
*/ |
20 |
|
21 |
#define WITH_OPENSSL |
22 |
#include "../rdesktop/rdesktop.h" |
23 |
|
24 |
#ifdef WITH_OPENSSL |
25 |
#include <openssl/rc4.h> |
26 |
#include <openssl/md5.h> |
27 |
#include <openssl/sha.h> |
28 |
#include <openssl/bn.h> |
29 |
#else |
30 |
#include "crypto/rc4.h" |
31 |
#include "crypto/md5.h" |
32 |
#include "crypto/sha.h" |
33 |
#include "crypto/bn.h" |
34 |
#endif |
35 |
|
36 |
extern char hostname[16]; |
37 |
extern int width; |
38 |
extern int height; |
39 |
extern int keylayout; |
40 |
extern BOOL encryption; |
41 |
extern BOOL licence_issued; |
42 |
|
43 |
static int rc4_key_len; |
44 |
static RC4_KEY rc4_decrypt_key; |
45 |
static RC4_KEY rc4_encrypt_key; |
46 |
static RC4_KEY rc4_encrypt_key2; |
47 |
|
48 |
static uint8 sec_sign_key[16]; |
49 |
static uint8 sec_decrypt_key[16]; |
50 |
static uint8 sec_encrypt_key[16]; |
51 |
static uint8 sec_encrypt_key2[16]; |
52 |
static uint8 sec_decrypt_update_key[16]; |
53 |
static uint8 sec_encrypt_update_key[16]; |
54 |
static uint8 sec_encrypt_update_key2[16]; |
55 |
static uint8 sec_crypted_random[SEC_MODULUS_SIZE]; |
56 |
|
57 |
/* |
58 |
* General purpose 48-byte transformation, using two 32-byte salts (generally, |
59 |
* a client and server salt) and a global salt value used for padding. |
60 |
* Both SHA1 and MD5 algorithms are used. |
61 |
*/ |
62 |
void |
63 |
sec_hash_48(uint8 * out, uint8 * in, uint8 * salt1, uint8 * salt2, uint8 salt) |
64 |
{ |
65 |
uint8 shasig[20]; |
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uint8 pad[4]; |
67 |
SHA_CTX sha; |
68 |
MD5_CTX md5; |
69 |
int i; |
70 |
|
71 |
for (i = 0; i < 3; i++) |
72 |
{ |
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memset(pad, salt + i, i + 1); |
74 |
|
75 |
SHA1_Init(&sha); |
76 |
SHA1_Update(&sha, pad, i + 1); |
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SHA1_Update(&sha, in, 48); |
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SHA1_Update(&sha, salt1, 32); |
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SHA1_Update(&sha, salt2, 32); |
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SHA1_Final(shasig, &sha); |
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|
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MD5_Init(&md5); |
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MD5_Update(&md5, in, 48); |
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MD5_Update(&md5, shasig, 20); |
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MD5_Final(&out[i * 16], &md5); |
86 |
} |
87 |
} |
88 |
|
89 |
/* |
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* Weaker 16-byte transformation, also using two 32-byte salts, but |
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* only using a single round of MD5. |
92 |
*/ |
93 |
void |
94 |
sec_hash_16(uint8 * out, uint8 * in, uint8 * salt1, uint8 * salt2) |
95 |
{ |
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MD5_CTX md5; |
97 |
|
98 |
MD5_Init(&md5); |
99 |
MD5_Update(&md5, in, 16); |
100 |
MD5_Update(&md5, salt1, 32); |
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MD5_Update(&md5, salt2, 32); |
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MD5_Final(out, &md5); |
103 |
} |
104 |
|
105 |
/* Reduce key entropy from 64 to 40 bits */ |
106 |
static void |
107 |
sec_make_40bit(uint8 * key) |
108 |
{ |
109 |
key[0] = 0xd1; |
110 |
key[1] = 0x26; |
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key[2] = 0x9e; |
112 |
} |
113 |
|
114 |
/* Generate a session key and RC4 keys, given client and server randoms */ |
115 |
void |
116 |
sec_generate_keys(uint8 * client_key, uint8 * server_key, int rc4_key_size) |
117 |
{ |
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uint8 session_key[48]; |
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uint8 temp_hash[48]; |
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uint8 input[48]; |
121 |
|
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/* Construct input data to hash */ |
123 |
memcpy(input, client_key, 24); |
124 |
memcpy(input + 24, server_key, 24); |
125 |
|
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/* Generate session key - two rounds of sec_hash_48 */ |
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sec_hash_48(temp_hash, input, client_key, server_key, 65); |
128 |
sec_hash_48(session_key, temp_hash, client_key, server_key, 88); |
129 |
|
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/* Store first 16 bytes of session key, for generating signatures */ |
131 |
memcpy(sec_sign_key, session_key, 16); |
132 |
|
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/* Generate RC4 keys */ |
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sec_hash_16(sec_decrypt_key, &session_key[16], client_key, server_key); |
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sec_hash_16(sec_encrypt_key, &session_key[32], client_key, server_key); |
136 |
|
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if (rc4_key_size == 1) |
138 |
{ |
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DEBUG(("40-bit encryption enabled\n")); |
140 |
sec_make_40bit(sec_sign_key); |
141 |
sec_make_40bit(sec_decrypt_key); |
142 |
sec_make_40bit(sec_encrypt_key); |
143 |
rc4_key_len = 8; |
144 |
} |
145 |
else |
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{ |
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DEBUG(("128-bit encryption enabled\n")); |
148 |
rc4_key_len = 16; |
149 |
} |
150 |
|
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/* Save initial RC4 keys as update keys */ |
152 |
memcpy(sec_decrypt_update_key, sec_decrypt_key, 16); |
153 |
memcpy(sec_encrypt_update_key, sec_encrypt_key, 16); |
154 |
memcpy(sec_encrypt_key2, sec_encrypt_key, 16); |
155 |
memcpy(sec_encrypt_update_key2, sec_encrypt_key2, 16); |
156 |
|
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/* Initialise RC4 state arrays */ |
158 |
RC4_set_key(&rc4_decrypt_key, rc4_key_len, sec_decrypt_key); |
159 |
RC4_set_key(&rc4_encrypt_key, rc4_key_len, sec_encrypt_key); |
160 |
RC4_set_key(&rc4_encrypt_key2, rc4_key_len, sec_encrypt_key2); |
161 |
} |
162 |
|
163 |
static uint8 pad_54[40] = { |
164 |
54, 54, 54, 54, 54, 54, 54, 54, 54, 54, 54, 54, 54, 54, 54, 54, 54, |
165 |
54, 54, 54, |
166 |
54, 54, 54, 54, 54, 54, 54, 54, 54, 54, 54, 54, 54, 54, 54, 54, 54, |
167 |
54, 54, 54 |
168 |
}; |
169 |
|
170 |
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, |
172 |
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 |
175 |
}; |
176 |
|
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// #if 0 |
178 |
/* Output a uint32 into a buffer (little-endian) */ |
179 |
void |
180 |
buf_out_uint32(uint8 * buffer, uint32 value) |
181 |
{ |
182 |
buffer[0] = (value) & 0xff; |
183 |
buffer[1] = (value >> 8) & 0xff; |
184 |
buffer[2] = (value >> 16) & 0xff; |
185 |
buffer[3] = (value >> 24) & 0xff; |
186 |
} |
187 |
|
188 |
void |
189 |
buf_out_uint16le(uint8 * buffer, uint16 value) |
190 |
{ |
191 |
buffer[0] = (value) & 0xff; |
192 |
buffer[1] = (value >> 8) & 0xff; |
193 |
} |
194 |
|
195 |
void |
196 |
buf_out_uint16be(uint8 * buffer, uint16 value) |
197 |
{ |
198 |
buffer[1] = (value) & 0xff; |
199 |
buffer[0] = (value >> 8) & 0xff; |
200 |
} |
201 |
|
202 |
uint32 |
203 |
buf_in_uint32le(uint8 * buffer) |
204 |
{ |
205 |
return (uint32) (buffer[0] | (buffer[1] << 8) | (buffer[2] << 16) | (buffer[3] << 24)); |
206 |
} |
207 |
|
208 |
uint16 |
209 |
buf_in_uint16be(uint8 * buffer) |
210 |
{ |
211 |
return (uint16) ((buffer[0] << 8) | buffer[1]); |
212 |
} |
213 |
|
214 |
|
215 |
|
216 |
/* Generate a signature hash, using a combination of SHA1 and MD5 */ |
217 |
void |
218 |
sec_sign(uint8 * signature, int siglen, uint8 * session_key, int keylen, uint8 * data, int datalen) |
219 |
{ |
220 |
uint8 shasig[20]; |
221 |
uint8 md5sig[16]; |
222 |
uint8 lenhdr[4]; |
223 |
SHA_CTX sha; |
224 |
MD5_CTX md5; |
225 |
|
226 |
buf_out_uint32(lenhdr, datalen); |
227 |
|
228 |
SHA1_Init(&sha); |
229 |
SHA1_Update(&sha, session_key, keylen); |
230 |
SHA1_Update(&sha, pad_54, 40); |
231 |
SHA1_Update(&sha, lenhdr, 4); |
232 |
SHA1_Update(&sha, data, datalen); |
233 |
SHA1_Final(shasig, &sha); |
234 |
|
235 |
MD5_Init(&md5); |
236 |
MD5_Update(&md5, session_key, keylen); |
237 |
MD5_Update(&md5, pad_92, 48); |
238 |
MD5_Update(&md5, shasig, 20); |
239 |
MD5_Final(md5sig, &md5); |
240 |
|
241 |
memcpy(signature, md5sig, siglen); |
242 |
} |
243 |
|
244 |
void |
245 |
sec_sign_buf(uint8 * signature, int siglen, uint8 * data, int datalen) |
246 |
{ |
247 |
sec_sign(signature, siglen, sec_sign_key, rc4_key_len, data, datalen); |
248 |
} |
249 |
|
250 |
|
251 |
|
252 |
// #endif |
253 |
|
254 |
/* Update an encryption key - similar to the signing process */ |
255 |
static void |
256 |
sec_update(uint8 * key, uint8 * update_key) |
257 |
{ |
258 |
uint8 shasig[20]; |
259 |
SHA_CTX sha; |
260 |
MD5_CTX md5; |
261 |
RC4_KEY update; |
262 |
|
263 |
SHA1_Init(&sha); |
264 |
SHA1_Update(&sha, update_key, rc4_key_len); |
265 |
SHA1_Update(&sha, pad_54, 40); |
266 |
SHA1_Update(&sha, key, rc4_key_len); |
267 |
SHA1_Final(shasig, &sha); |
268 |
|
269 |
MD5_Init(&md5); |
270 |
MD5_Update(&md5, update_key, rc4_key_len); |
271 |
MD5_Update(&md5, pad_92, 48); |
272 |
MD5_Update(&md5, shasig, 20); |
273 |
MD5_Final(key, &md5); |
274 |
|
275 |
RC4_set_key(&update, rc4_key_len, key); |
276 |
RC4(&update, rc4_key_len, key, key); |
277 |
|
278 |
if (rc4_key_len == 8) |
279 |
sec_make_40bit(key); |
280 |
} |
281 |
|
282 |
/* Encrypt data using RC4 */ |
283 |
void |
284 |
sec_encrypt(uint8 * data, int length) |
285 |
{ |
286 |
static int use_count; |
287 |
|
288 |
if (use_count == 4096) |
289 |
{ |
290 |
sec_update(sec_encrypt_key, sec_encrypt_update_key); |
291 |
RC4_set_key(&rc4_encrypt_key, rc4_key_len, sec_encrypt_key); |
292 |
use_count = 0; |
293 |
} |
294 |
|
295 |
RC4(&rc4_encrypt_key, length, data, data); |
296 |
use_count++; |
297 |
} |
298 |
|
299 |
/* Encrypt data using RC4 */ |
300 |
void |
301 |
sec_encrypt2(uint8 * data, int length) |
302 |
{ |
303 |
static int use_count; |
304 |
|
305 |
if (use_count == 4096) |
306 |
{ |
307 |
sec_update(sec_encrypt_key2, sec_encrypt_update_key2); |
308 |
RC4_set_key(&rc4_encrypt_key2, rc4_key_len, sec_encrypt_key2); |
309 |
use_count = 0; |
310 |
} |
311 |
|
312 |
RC4(&rc4_encrypt_key2, length, data, data); |
313 |
use_count++; |
314 |
} |
315 |
|
316 |
/* Decrypt data using RC4 */ |
317 |
void |
318 |
sec_decrypt(uint8 * data, int length) |
319 |
{ |
320 |
static int use_count; |
321 |
|
322 |
if (use_count == 4096) |
323 |
{ |
324 |
sec_update(sec_decrypt_key, sec_decrypt_update_key); |
325 |
RC4_set_key(&rc4_decrypt_key, rc4_key_len, sec_decrypt_key); |
326 |
use_count = 0; |
327 |
} |
328 |
|
329 |
RC4(&rc4_decrypt_key, length, data, data); |
330 |
use_count++; |
331 |
} |
332 |
|
333 |
#if 0 |
334 |
static void |
335 |
reverse(uint8 * p, int len) |
336 |
{ |
337 |
int i, j; |
338 |
uint8 temp; |
339 |
|
340 |
for (i = 0, j = len - 1; i < j; i++, j--) |
341 |
{ |
342 |
temp = p[i]; |
343 |
p[i] = p[j]; |
344 |
p[j] = temp; |
345 |
} |
346 |
} |
347 |
|
348 |
/* Perform an RSA public key encryption operation */ |
349 |
static void |
350 |
sec_rsa_encrypt(uint8 * out, uint8 * in, int len, uint8 * modulus, uint8 * exponent) |
351 |
{ |
352 |
BN_CTX ctx; |
353 |
BIGNUM mod, exp, x, y; |
354 |
uint8 inr[SEC_MODULUS_SIZE]; |
355 |
int outlen; |
356 |
|
357 |
reverse(modulus, SEC_MODULUS_SIZE); |
358 |
reverse(exponent, SEC_EXPONENT_SIZE); |
359 |
memcpy(inr, in, len); |
360 |
reverse(inr, len); |
361 |
|
362 |
BN_CTX_init(&ctx); |
363 |
BN_init(&mod); |
364 |
BN_init(&exp); |
365 |
BN_init(&x); |
366 |
BN_init(&y); |
367 |
|
368 |
BN_bin2bn(modulus, SEC_MODULUS_SIZE, &mod); |
369 |
BN_bin2bn(exponent, SEC_EXPONENT_SIZE, &exp); |
370 |
BN_bin2bn(inr, len, &x); |
371 |
BN_mod_exp(&y, &x, &exp, &mod, &ctx); |
372 |
outlen = BN_bn2bin(&y, out); |
373 |
reverse(out, outlen); |
374 |
if (outlen < SEC_MODULUS_SIZE) |
375 |
memset(out + outlen, 0, SEC_MODULUS_SIZE - outlen); |
376 |
|
377 |
BN_free(&y); |
378 |
BN_clear_free(&x); |
379 |
BN_free(&exp); |
380 |
BN_free(&mod); |
381 |
BN_CTX_free(&ctx); |
382 |
} |
383 |
|
384 |
/* Initialise secure transport packet */ |
385 |
STREAM |
386 |
sec_init(uint32 flags, int maxlen) |
387 |
{ |
388 |
int hdrlen; |
389 |
STREAM s; |
390 |
|
391 |
if (!licence_issued) |
392 |
hdrlen = (flags & SEC_ENCRYPT) ? 12 : 4; |
393 |
else |
394 |
hdrlen = (flags & SEC_ENCRYPT) ? 12 : 0; |
395 |
s = mcs_init(maxlen + hdrlen); |
396 |
s_push_layer(s, sec_hdr, hdrlen); |
397 |
|
398 |
return s; |
399 |
} |
400 |
|
401 |
/* Transmit secure transport packet */ |
402 |
void |
403 |
sec_send(STREAM s, uint32 flags) |
404 |
{ |
405 |
int datalen; |
406 |
|
407 |
s_pop_layer(s, sec_hdr); |
408 |
if (!licence_issued || (flags & SEC_ENCRYPT)) |
409 |
out_uint32_le(s, flags); |
410 |
|
411 |
if (flags & SEC_ENCRYPT) |
412 |
{ |
413 |
flags &= ~SEC_ENCRYPT; |
414 |
datalen = s->end - s->p - 8; |
415 |
|
416 |
#if WITH_DEBUG |
417 |
DEBUG(("Sending encrypted packet:\n")); |
418 |
hexdump(s->p + 8, datalen); |
419 |
#endif |
420 |
|
421 |
sec_sign(s->p, 8, sec_sign_key, rc4_key_len, s->p + 8, datalen); |
422 |
sec_encrypt(s->p + 8, datalen); |
423 |
} |
424 |
|
425 |
mcs_send(s); |
426 |
} |
427 |
|
428 |
/* Transfer the client random to the server */ |
429 |
static void |
430 |
sec_establish_key() |
431 |
{ |
432 |
uint32 length = SEC_MODULUS_SIZE + SEC_PADDING_SIZE; |
433 |
uint32 flags = SEC_CLIENT_RANDOM; |
434 |
STREAM s; |
435 |
|
436 |
s = sec_init(flags, 76); |
437 |
|
438 |
out_uint32_le(s, length); |
439 |
out_uint8p(s, sec_crypted_random, SEC_MODULUS_SIZE); |
440 |
out_uint8s(s, SEC_PADDING_SIZE); |
441 |
|
442 |
s_mark_end(s); |
443 |
sec_send(s, flags); |
444 |
} |
445 |
|
446 |
/* Output connect initial data blob */ |
447 |
static void |
448 |
sec_out_mcs_data(STREAM s) |
449 |
{ |
450 |
int hostlen = 2 * strlen(hostname); |
451 |
|
452 |
out_uint16_be(s, 5); /* unknown */ |
453 |
out_uint16_be(s, 0x14); |
454 |
out_uint8(s, 0x7c); |
455 |
out_uint16_be(s, 1); |
456 |
|
457 |
out_uint16_be(s, (158 | 0x8000)); /* remaining length */ |
458 |
|
459 |
out_uint16_be(s, 8); /* length? */ |
460 |
out_uint16_be(s, 16); |
461 |
out_uint8(s, 0); |
462 |
out_uint16_le(s, 0xc001); |
463 |
out_uint8(s, 0); |
464 |
|
465 |
out_uint32_le(s, 0x61637544); /* "Duca" ?! */ |
466 |
out_uint16_be(s, (144 | 0x8000)); /* remaining length */ |
467 |
|
468 |
/* Client information */ |
469 |
out_uint16_le(s, SEC_TAG_CLI_INFO); |
470 |
out_uint16_le(s, 136); /* length */ |
471 |
out_uint16_le(s, 1); |
472 |
out_uint16_le(s, 8); |
473 |
out_uint16_le(s, width); |
474 |
out_uint16_le(s, height); |
475 |
out_uint16_le(s, 0xca01); |
476 |
out_uint16_le(s, 0xaa03); |
477 |
out_uint32_le(s, keylayout); |
478 |
out_uint32_le(s, 419); /* client build? we are 419 compatible :-) */ |
479 |
|
480 |
/* Unicode name of client, padded to 32 bytes */ |
481 |
rdp_out_unistr(s, hostname, hostlen); |
482 |
out_uint8s(s, 30 - hostlen); |
483 |
|
484 |
out_uint32_le(s, 4); |
485 |
out_uint32(s, 0); |
486 |
out_uint32_le(s, 12); |
487 |
out_uint8s(s, 64); /* reserved? 4 + 12 doublewords */ |
488 |
|
489 |
out_uint16_le(s, 0xca01); |
490 |
out_uint16(s, 0); |
491 |
|
492 |
/* Client encryption settings */ |
493 |
out_uint16_le(s, SEC_TAG_CLI_CRYPT); |
494 |
out_uint16_le(s, 8); /* length */ |
495 |
out_uint32_le(s, encryption ? 0x3 : 0); /* encryption supported, 128-bit supported */ |
496 |
s_mark_end(s); |
497 |
} |
498 |
|
499 |
/* Parse a public key structure */ |
500 |
static BOOL |
501 |
sec_parse_public_key(STREAM s, uint8 ** modulus, uint8 ** exponent) |
502 |
{ |
503 |
uint32 magic, modulus_len; |
504 |
|
505 |
in_uint32_le(s, magic); |
506 |
if (magic != SEC_RSA_MAGIC) |
507 |
{ |
508 |
error("RSA magic 0x%x\n", magic); |
509 |
return False; |
510 |
} |
511 |
|
512 |
in_uint32_le(s, modulus_len); |
513 |
if (modulus_len != SEC_MODULUS_SIZE + SEC_PADDING_SIZE) |
514 |
{ |
515 |
error("modulus len 0x%x\n", modulus_len); |
516 |
return False; |
517 |
} |
518 |
|
519 |
in_uint8s(s, 8); /* modulus_bits, unknown */ |
520 |
in_uint8p(s, *exponent, SEC_EXPONENT_SIZE); |
521 |
in_uint8p(s, *modulus, SEC_MODULUS_SIZE); |
522 |
in_uint8s(s, SEC_PADDING_SIZE); |
523 |
|
524 |
return s_check(s); |
525 |
} |
526 |
|
527 |
/* Parse a crypto information structure */ |
528 |
static BOOL |
529 |
sec_parse_crypt_info(STREAM s, uint32 * rc4_key_size, |
530 |
uint8 ** server_random, uint8 ** modulus, uint8 ** exponent) |
531 |
{ |
532 |
uint32 crypt_level, random_len, rsa_info_len; |
533 |
uint16 tag, length; |
534 |
uint8 *next_tag, *end; |
535 |
|
536 |
in_uint32_le(s, *rc4_key_size); /* 1 = 40-bit, 2 = 128-bit */ |
537 |
in_uint32_le(s, crypt_level); /* 1 = low, 2 = medium, 3 = high */ |
538 |
in_uint32_le(s, random_len); |
539 |
in_uint32_le(s, rsa_info_len); |
540 |
|
541 |
if (random_len != SEC_RANDOM_SIZE) |
542 |
{ |
543 |
error("random len %d\n", random_len); |
544 |
return False; |
545 |
} |
546 |
|
547 |
in_uint8p(s, *server_random, random_len); |
548 |
|
549 |
/* RSA info */ |
550 |
end = s->p + rsa_info_len; |
551 |
if (end > s->end) |
552 |
return False; |
553 |
|
554 |
in_uint8s(s, 12); /* unknown */ |
555 |
|
556 |
while (s->p < end) |
557 |
{ |
558 |
in_uint16_le(s, tag); |
559 |
in_uint16_le(s, length); |
560 |
|
561 |
next_tag = s->p + length; |
562 |
|
563 |
switch (tag) |
564 |
{ |
565 |
case SEC_TAG_PUBKEY: |
566 |
if (!sec_parse_public_key(s, modulus, exponent)) |
567 |
return False; |
568 |
|
569 |
break; |
570 |
|
571 |
case SEC_TAG_KEYSIG: |
572 |
/* Is this a Microsoft key that we just got? */ |
573 |
/* Care factor: zero! */ |
574 |
break; |
575 |
|
576 |
default: |
577 |
unimpl("crypt tag 0x%x\n", tag); |
578 |
} |
579 |
|
580 |
s->p = next_tag; |
581 |
} |
582 |
|
583 |
return s_check_end(s); |
584 |
} |
585 |
|
586 |
/* Process crypto information blob */ |
587 |
static void |
588 |
sec_process_crypt_info(STREAM s) |
589 |
{ |
590 |
uint8 *server_random, *modulus, *exponent; |
591 |
uint8 client_random[SEC_RANDOM_SIZE]; |
592 |
uint32 rc4_key_size; |
593 |
|
594 |
if (!sec_parse_crypt_info(s, &rc4_key_size, &server_random, &modulus, &exponent)) |
595 |
return; |
596 |
|
597 |
/* Generate a client random, and hence determine encryption keys */ |
598 |
generate_random(client_random); |
599 |
sec_rsa_encrypt(sec_crypted_random, client_random, SEC_RANDOM_SIZE, modulus, exponent); |
600 |
sec_generate_keys(client_random, server_random, rc4_key_size); |
601 |
} |
602 |
|
603 |
/* Process connect response data blob */ |
604 |
static void |
605 |
sec_process_mcs_data(STREAM s) |
606 |
{ |
607 |
uint16 tag, length; |
608 |
uint8 *next_tag; |
609 |
|
610 |
in_uint8s(s, 23); /* header */ |
611 |
|
612 |
while (s->p < s->end) |
613 |
{ |
614 |
in_uint16_le(s, tag); |
615 |
in_uint16_le(s, length); |
616 |
|
617 |
if (length <= 4) |
618 |
return; |
619 |
|
620 |
next_tag = s->p + length - 4; |
621 |
|
622 |
switch (tag) |
623 |
{ |
624 |
case SEC_TAG_SRV_INFO: |
625 |
case SEC_TAG_SRV_3: |
626 |
break; |
627 |
|
628 |
case SEC_TAG_SRV_CRYPT: |
629 |
sec_process_crypt_info(s); |
630 |
break; |
631 |
|
632 |
default: |
633 |
unimpl("response tag 0x%x\n", tag); |
634 |
} |
635 |
|
636 |
s->p = next_tag; |
637 |
} |
638 |
} |
639 |
|
640 |
/* Receive secure transport packet */ |
641 |
STREAM |
642 |
sec_recv() |
643 |
{ |
644 |
uint32 sec_flags; |
645 |
STREAM s; |
646 |
|
647 |
while ((s = mcs_recv()) != NULL) |
648 |
{ |
649 |
if (encryption || !licence_issued) |
650 |
{ |
651 |
in_uint32_le(s, sec_flags); |
652 |
|
653 |
if (sec_flags & SEC_LICENCE_NEG) |
654 |
{ |
655 |
licence_process(s); |
656 |
continue; |
657 |
} |
658 |
|
659 |
if (sec_flags & SEC_ENCRYPT) |
660 |
{ |
661 |
in_uint8s(s, 8); /* signature */ |
662 |
sec_decrypt(s->p, s->end - s->p); |
663 |
} |
664 |
} |
665 |
|
666 |
return s; |
667 |
} |
668 |
|
669 |
return NULL; |
670 |
} |
671 |
|
672 |
/* Establish a secure connection */ |
673 |
BOOL |
674 |
sec_connect(char *server) |
675 |
{ |
676 |
struct stream mcs_data; |
677 |
|
678 |
/* We exchange some RDP data during the MCS-Connect */ |
679 |
mcs_data.size = 512; |
680 |
mcs_data.p = mcs_data.data = xmalloc(mcs_data.size); |
681 |
sec_out_mcs_data(&mcs_data); |
682 |
|
683 |
if (!mcs_connect(server, &mcs_data)) |
684 |
return False; |
685 |
|
686 |
sec_process_mcs_data(&mcs_data); |
687 |
if (encryption) |
688 |
sec_establish_key(); |
689 |
return True; |
690 |
} |
691 |
|
692 |
/* Disconnect a connection */ |
693 |
void |
694 |
sec_disconnect() |
695 |
{ |
696 |
mcs_disconnect(); |
697 |
} |
698 |
#endif |