secure.c@ 11982

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1	/* -- c-basic-offset: 8 --
2	rdesktop: A Remote Desktop Protocol client.
3	Protocol services - RDP encryption and licensing
4	Copyright (C) Matthew Chapman 1999-2007
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
11	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
14	GNU General Public License for more details.
15
16	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	/*
22	* Sun GPL Disclaimer: For the avoidance of doubt, except that if any license choice
23	* other than GPL or LGPL is available it will apply instead, Sun elects to use only
24	* the General Public License version 2 (GPLv2) at this time for any software where
25	* a choice of GPL license versions is made available with the language indicating
26	* that GPLv2 or any later version may be used, or where a choice of which version
27	* of the GPL is applied is otherwise unspecified.
28	*/
29
30	#include "rdesktop.h"
31	#include "ssl.h"
32
33	extern char g_hostname[16];
34	extern int g_width;
35	extern int g_height;
36	extern unsigned int g_keylayout;
37	extern int g_keyboard_type;
38	extern int g_keyboard_subtype;
39	extern int g_keyboard_functionkeys;
40	extern RD_BOOL g_encryption;
41	extern RD_BOOL g_licence_issued;
42	extern RD_BOOL g_use_rdp5;
43	extern RD_BOOL g_console_session;
44	extern int g_server_depth;
45	extern VCHANNEL g_channels[];
46	extern unsigned int g_num_channels;
47
48	static int g_rc4_key_len;
49	static SSL_RC4 g_rc4_decrypt_key;
50	static SSL_RC4 g_rc4_encrypt_key;
51	static uint32 g_server_public_key_len;
52
53	static uint8 g_sec_sign_key[16];
54	static uint8 g_sec_decrypt_key[16];
55	static uint8 g_sec_encrypt_key[16];
56	static uint8 g_sec_decrypt_update_key[16];
57	static uint8 g_sec_encrypt_update_key[16];
58	static uint8 g_sec_crypted_random[SEC_MAX_MODULUS_SIZE];
59
60	uint16 g_server_rdp_version = 0;
61
62	/* These values must be available to reset state - Session Directory */
63	static int g_sec_encrypt_use_count = 0;
64	static int g_sec_decrypt_use_count = 0;
65
66	/*
67	* I believe this is based on SSLv3 with the following differences:
68	* MAC algorithm (5.2.3.1) uses only 32-bit length in place of seq_num/type/length fields
69	* MAC algorithm uses SHA1 and MD5 for the two hash functions instead of one or other
70	* key_block algorithm (6.2.2) uses 'X', 'YY', 'ZZZ' instead of 'A', 'BB', 'CCC'
71	* key_block partitioning is different (16 bytes each: MAC secret, decrypt key, encrypt key)
72	* encryption/decryption keys updated every 4096 packets
73	* See http://wp.netscape.com/eng/ssl3/draft302.txt
74	*/
75
76	/*
77	* 48-byte transformation used to generate master secret (6.1) and key material (6.2.2).
78	* Both SHA1 and MD5 algorithms are used.
79	*/
80	void
81	sec_hash_48(uint8 * out, uint8 * in, uint8 * salt1, uint8 * salt2, uint8 salt)
82	{
83	uint8 shasig[20];
84	uint8 pad[4];
85	SSL_SHA1 sha1;
86	SSL_MD5 md5;
87	int i;
88
89	for (i = 0; i < 3; i++)
90	{
91	memset(pad, salt + i, i + 1);
92
93	ssl_sha1_init(&sha1);
94	ssl_sha1_update(&sha1, pad, i + 1);
95	ssl_sha1_update(&sha1, in, 48);
96	ssl_sha1_update(&sha1, salt1, 32);
97	ssl_sha1_update(&sha1, salt2, 32);
98	ssl_sha1_final(&sha1, shasig);
99
100	ssl_md5_init(&md5);
101	ssl_md5_update(&md5, in, 48);
102	ssl_md5_update(&md5, shasig, 20);
103	ssl_md5_final(&md5, &out[i * 16]);
104	}
105	}
106
107	/*
108	* 16-byte transformation used to generate export keys (6.2.2).
109	*/
110	void
111	sec_hash_16(uint8 * out, uint8 * in, uint8 * salt1, uint8 * salt2)
112	{
113	SSL_MD5 md5;
114
115	ssl_md5_init(&md5);
116	ssl_md5_update(&md5, in, 16);
117	ssl_md5_update(&md5, salt1, 32);
118	ssl_md5_update(&md5, salt2, 32);
119	ssl_md5_final(&md5, out);
120	}
121
122	/* Reduce key entropy from 64 to 40 bits */
123	static void
124	sec_make_40bit(uint8 * key)
125	{
126	key[0] = 0xd1;
127	key[1] = 0x26;
128	key[2] = 0x9e;
129	}
130
131	/* Generate encryption keys given client and server randoms */
132	static void
133	sec_generate_keys(uint8 * client_random, uint8 * server_random, int rc4_key_size)
134	{
135	uint8 pre_master_secret[48];
136	uint8 master_secret[48];
137	uint8 key_block[48];
138
139	/* Construct pre-master secret */
140	memcpy(pre_master_secret, client_random, 24);
141	memcpy(pre_master_secret + 24, server_random, 24);
142
143	/* Generate master secret and then key material */
144	sec_hash_48(master_secret, pre_master_secret, client_random, server_random, 'A');
145	sec_hash_48(key_block, master_secret, client_random, server_random, 'X');
146
147	/* First 16 bytes of key material is MAC secret */
148	memcpy(g_sec_sign_key, key_block, 16);
149
150	/* Generate export keys from next two blocks of 16 bytes */
151	sec_hash_16(g_sec_decrypt_key, &key_block[16], client_random, server_random);
152	sec_hash_16(g_sec_encrypt_key, &key_block[32], client_random, server_random);
153
154	if (rc4_key_size == 1)
155	{
156	DEBUG(("40-bit encryption enabled\n"));
157	sec_make_40bit(g_sec_sign_key);
158	sec_make_40bit(g_sec_decrypt_key);
159	sec_make_40bit(g_sec_encrypt_key);
160	g_rc4_key_len = 8;
161	}
162	else
163	{
164	DEBUG(("rc_4_key_size == %d, 128-bit encryption enabled\n", rc4_key_size));
165	g_rc4_key_len = 16;
166	}
167
168	/* Save initial RC4 keys as update keys */
169	memcpy(g_sec_decrypt_update_key, g_sec_decrypt_key, 16);
170	memcpy(g_sec_encrypt_update_key, g_sec_encrypt_key, 16);
171
172	/* Initialise RC4 state arrays */
173	ssl_rc4_set_key(&g_rc4_decrypt_key, g_sec_decrypt_key, g_rc4_key_len);
174	ssl_rc4_set_key(&g_rc4_encrypt_key, g_sec_encrypt_key, g_rc4_key_len);
175	}
176
177	static uint8 pad_54[40] = {
178	54, 54, 54, 54, 54, 54, 54, 54, 54, 54, 54, 54, 54, 54, 54, 54, 54,
179	54, 54, 54,
180	54, 54, 54, 54, 54, 54, 54, 54, 54, 54, 54, 54, 54, 54, 54, 54, 54,
181	54, 54, 54
182	};
183
184	static uint8 pad_92[48] = {
185	92, 92, 92, 92, 92, 92, 92, 92, 92, 92, 92, 92, 92, 92, 92, 92, 92,
186	92, 92, 92, 92, 92, 92, 92,
187	92, 92, 92, 92, 92, 92, 92, 92, 92, 92, 92, 92, 92, 92, 92, 92, 92,
188	92, 92, 92, 92, 92, 92, 92
189	};
190
191	/* Output a uint32 into a buffer (little-endian) */
192	void
193	buf_out_uint32(uint8 * buffer, uint32 value)
194	{
195	buffer[0] = (value) & 0xff;
196	buffer[1] = (value >> 8) & 0xff;
197	buffer[2] = (value >> 16) & 0xff;
198	buffer[3] = (value >> 24) & 0xff;
199	}
200
201	/* Generate a MAC hash (5.2.3.1), using a combination of SHA1 and MD5 */
202	void
203	sec_sign(uint8 * signature, int siglen, uint8 * session_key, int keylen, uint8 * data, int datalen)
204	{
205	uint8 shasig[20];
206	uint8 md5sig[16];
207	uint8 lenhdr[4];
208	SSL_SHA1 sha1;
209	SSL_MD5 md5;
210
211	buf_out_uint32(lenhdr, datalen);
212
213	ssl_sha1_init(&sha1);
214	ssl_sha1_update(&sha1, session_key, keylen);
215	ssl_sha1_update(&sha1, pad_54, 40);
216	ssl_sha1_update(&sha1, lenhdr, 4);
217	ssl_sha1_update(&sha1, data, datalen);
218	ssl_sha1_final(&sha1, shasig);
219
220	ssl_md5_init(&md5);
221	ssl_md5_update(&md5, session_key, keylen);
222	ssl_md5_update(&md5, pad_92, 48);
223	ssl_md5_update(&md5, shasig, 20);
224	ssl_md5_final(&md5, md5sig);
225
226	memcpy(signature, md5sig, siglen);
227	}
228
229	/* Update an encryption key */
230	static void
231	sec_update(uint8 * key, uint8 * update_key)
232	{
233	uint8 shasig[20];
234	SSL_SHA1 sha1;
235	SSL_MD5 md5;
236	SSL_RC4 update;
237
238	ssl_sha1_init(&sha1);
239	ssl_sha1_update(&sha1, update_key, g_rc4_key_len);
240	ssl_sha1_update(&sha1, pad_54, 40);
241	ssl_sha1_update(&sha1, key, g_rc4_key_len);
242	ssl_sha1_final(&sha1, shasig);
243
244	ssl_md5_init(&md5);
245	ssl_md5_update(&md5, update_key, g_rc4_key_len);
246	ssl_md5_update(&md5, pad_92, 48);
247	ssl_md5_update(&md5, shasig, 20);
248	ssl_md5_final(&md5, key);
249
250	ssl_rc4_set_key(&update, key, g_rc4_key_len);
251	ssl_rc4_crypt(&update, key, key, g_rc4_key_len);
252
253	if (g_rc4_key_len == 8)
254	sec_make_40bit(key);
255	}
256
257	/* Encrypt data using RC4 */
258	static void
259	sec_encrypt(uint8 * data, int length)
260	{
261	if (g_sec_encrypt_use_count == 4096)
262	{
263	sec_update(g_sec_encrypt_key, g_sec_encrypt_update_key);
264	ssl_rc4_set_key(&g_rc4_encrypt_key, g_sec_encrypt_key, g_rc4_key_len);
265	g_sec_encrypt_use_count = 0;
266	}
267
268	ssl_rc4_crypt(&g_rc4_encrypt_key, data, data, length);
269	g_sec_encrypt_use_count++;
270	}
271
272	/* Decrypt data using RC4 */
273	void
274	sec_decrypt(uint8 * data, int length)
275	{
276	if (g_sec_decrypt_use_count == 4096)
277	{
278	sec_update(g_sec_decrypt_key, g_sec_decrypt_update_key);
279	ssl_rc4_set_key(&g_rc4_decrypt_key, g_sec_decrypt_key, g_rc4_key_len);
280	g_sec_decrypt_use_count = 0;
281	}
282
283	ssl_rc4_crypt(&g_rc4_decrypt_key, data, data, length);
284	g_sec_decrypt_use_count++;
285	}
286
287	/* Perform an RSA public key encryption operation */
288	static void
289	sec_rsa_encrypt(uint8 * out, uint8 * in, int len, uint32 modulus_size, uint8 * modulus,
290	uint8 * exponent)
291	{
292	ssl_rsa_encrypt(out, in, len, modulus_size, modulus, exponent);
293	}
294
295	/* Initialise secure transport packet */
296	STREAM
297	sec_init(uint32 flags, int maxlen)
298	{
299	int hdrlen;
300	STREAM s;
301
302	if (!g_licence_issued)
303	hdrlen = (flags & SEC_ENCRYPT) ? 12 : 4;
304	else
305	hdrlen = (flags & SEC_ENCRYPT) ? 12 : 0;
306	s = mcs_init(maxlen + hdrlen);
307	s_push_layer(s, sec_hdr, hdrlen);
308
309	return s;
310	}
311
312	/* Transmit secure transport packet over specified channel */
313	void
314	sec_send_to_channel(STREAM s, uint32 flags, uint16 channel)
315	{
316	int datalen;
317
318	#ifdef WITH_SCARD
319	scard_lock(SCARD_LOCK_SEC);
320	#endif
321
322	s_pop_layer(s, sec_hdr);
323	if (!g_licence_issued \|\| (flags & SEC_ENCRYPT))
324	out_uint32_le(s, flags);
325
326	if (flags & SEC_ENCRYPT)
327	{
328	flags &= ~SEC_ENCRYPT;
329	datalen = s->end - s->p - 8;
330
331	#if WITH_DEBUG
332	DEBUG(("Sending encrypted packet:\n"));
333	hexdump(s->p + 8, datalen);
334	#endif
335
336	sec_sign(s->p, 8, g_sec_sign_key, g_rc4_key_len, s->p + 8, datalen);
337	sec_encrypt(s->p + 8, datalen);
338	}
339
340	mcs_send_to_channel(s, channel);
341
342	#ifdef WITH_SCARD
343	scard_unlock(SCARD_LOCK_SEC);
344	#endif
345	}
346
347	/* Transmit secure transport packet */
348
349	void
350	sec_send(STREAM s, uint32 flags)
351	{
352	sec_send_to_channel(s, flags, MCS_GLOBAL_CHANNEL);
353	}
354
355
356	/* Transfer the client random to the server */
357	static void
358	sec_establish_key(void)
359	{
360	uint32 length = g_server_public_key_len + SEC_PADDING_SIZE;
361	uint32 flags = SEC_CLIENT_RANDOM;
362	STREAM s;
363
364	s = sec_init(flags, length + 4);
365
366	out_uint32_le(s, length);
367	out_uint8p(s, g_sec_crypted_random, g_server_public_key_len);
368	out_uint8s(s, SEC_PADDING_SIZE);
369
370	s_mark_end(s);
371	sec_send(s, flags);
372	}
373
374	/* Output connect initial data blob */
375	static void
376	sec_out_mcs_data(STREAM s)
377	{
378	int hostlen = 2 * strlen(g_hostname);
379	int length = 158 + 76 + 12 + 4;
380	unsigned int i;
381
382	if (g_num_channels > 0)
383	length += g_num_channels * 12 + 8;
384
385	if (hostlen > 30)
386	hostlen = 30;
387
388	/* Generic Conference Control (T.124) ConferenceCreateRequest */
389	out_uint16_be(s, 5);
390	out_uint16_be(s, 0x14);
391	out_uint8(s, 0x7c);
392	out_uint16_be(s, 1);
393
394	out_uint16_be(s, (length \| 0x8000)); /* remaining length */
395
396	out_uint16_be(s, 8); /* length? */
397	out_uint16_be(s, 16);
398	out_uint8(s, 0);
399	out_uint16_le(s, 0xc001);
400	out_uint8(s, 0);
401
402	out_uint32_le(s, 0x61637544); /* OEM ID: "Duca", as in Ducati. */
403	out_uint16_be(s, ((length - 14) \| 0x8000)); /* remaining length */
404
405	/* Client information */
406	out_uint16_le(s, SEC_TAG_CLI_INFO);
407	out_uint16_le(s, 212); /* length */
408	out_uint16_le(s, g_use_rdp5 ? 4 : 1); /* RDP version. 1 == RDP4, 4 == RDP5. */
409	out_uint16_le(s, 8);
410	out_uint16_le(s, g_width);
411	out_uint16_le(s, g_height);
412	out_uint16_le(s, 0xca01);
413	out_uint16_le(s, 0xaa03);
414	out_uint32_le(s, g_keylayout);
415	out_uint32_le(s, 2600); /* Client build. We are now 2600 compatible :-) */
416
417	/* Unicode name of client, padded to 32 bytes */
418	rdp_out_unistr(s, g_hostname, hostlen);
419	out_uint8s(s, 30 - hostlen);
420
421	/* See
422	http://msdn.microsoft.com/library/default.asp?url=/library/en-us/wceddk40/html/cxtsksupportingremotedesktopprotocol.asp */
423	out_uint32_le(s, g_keyboard_type);
424	out_uint32_le(s, g_keyboard_subtype);
425	out_uint32_le(s, g_keyboard_functionkeys);
426	out_uint8s(s, 64); /* reserved? 4 + 12 doublewords */
427	out_uint16_le(s, 0xca01); /* colour depth? */
428	out_uint16_le(s, 1);
429
430	out_uint32(s, 0);
431	out_uint8(s, g_server_depth);
432	out_uint16_le(s, 0x0700);
433	out_uint8(s, 0);
434	out_uint32_le(s, 1);
435	out_uint8s(s, 64); /* End of client info */
436
437	out_uint16_le(s, SEC_TAG_CLI_4);
438	out_uint16_le(s, 12);
439	out_uint32_le(s, g_console_session ? 0xb : 9);
440	out_uint32(s, 0);
441
442	/* Client encryption settings */
443	out_uint16_le(s, SEC_TAG_CLI_CRYPT);
444	out_uint16_le(s, 12); /* length */
445	out_uint32_le(s, g_encryption ? 0x3 : 0); /* encryption supported, 128-bit supported */
446	out_uint32(s, 0); /* Unknown */
447
448	DEBUG_RDP5(("g_num_channels is %d\n", g_num_channels));
449	if (g_num_channels > 0)
450	{
451	out_uint16_le(s, SEC_TAG_CLI_CHANNELS);
452	out_uint16_le(s, g_num_channels * 12 + 8); /* length */
453	out_uint32_le(s, g_num_channels); /* number of virtual channels */
454	for (i = 0; i < g_num_channels; i++)
455	{
456	DEBUG_RDP5(("Requesting channel %s\n", g_channels[i].name));
457	out_uint8a(s, g_channels[i].name, 8);
458	out_uint32_be(s, g_channels[i].flags);
459	}
460	}
461
462	s_mark_end(s);
463	}
464
465	/* Parse a public key structure */
466	static RD_BOOL
467	sec_parse_public_key(STREAM s, uint8 * modulus, uint8 * exponent)
468	{
469	uint32 magic, modulus_len;
470
471	in_uint32_le(s, magic);
472	if (magic != SEC_RSA_MAGIC)
473	{
474	error("RSA magic 0x%x\n", magic);
475	return False;
476	}
477
478	in_uint32_le(s, modulus_len);
479	modulus_len -= SEC_PADDING_SIZE;
480	if ((modulus_len < SEC_MODULUS_SIZE) \|\| (modulus_len > SEC_MAX_MODULUS_SIZE))
481	{
482	error("Bad server public key size (%u bits)\n", modulus_len * 8);
483	return False;
484	}
485
486	in_uint8s(s, 8); /* modulus_bits, unknown */
487	in_uint8a(s, exponent, SEC_EXPONENT_SIZE);
488	in_uint8a(s, modulus, modulus_len);
489	in_uint8s(s, SEC_PADDING_SIZE);
490	g_server_public_key_len = modulus_len;
491
492	return s_check(s);
493	}
494
495	/* Parse a public signature structure */
496	static RD_BOOL
497	sec_parse_public_sig(STREAM s, uint32 len, uint8 * modulus, uint8 * exponent)
498	{
499	uint8 signature[SEC_MAX_MODULUS_SIZE];
500	uint32 sig_len;
501
502	if (len != 72)
503	{
504	return True;
505	}
506	memset(signature, 0, sizeof(signature));
507	sig_len = len - 8;
508	in_uint8a(s, signature, sig_len);
509	return ssl_sig_ok(exponent, SEC_EXPONENT_SIZE, modulus, g_server_public_key_len,
510	signature, sig_len);
511	}
512
513	/* Parse a crypto information structure */
514	static RD_BOOL
515	sec_parse_crypt_info(STREAM s, uint32 * rc4_key_size,
516	uint8 ** server_random, uint8 * modulus, uint8 * exponent)
517	{
518	uint32 crypt_level, random_len, rsa_info_len;
519	uint32 cacert_len, cert_len, flags;
520	SSL_CERT cacert, server_cert;
521	SSL_RKEY *server_public_key;
522	uint16 tag, length;
523	uint8 next_tag, end;
524
525	in_uint32_le(s, rc4_key_size); / 1 = 40-bit, 2 = 128-bit */
526	in_uint32_le(s, crypt_level); /* 1 = low, 2 = medium, 3 = high */
527	if (crypt_level == 0) /* no encryption */
528	return False;
529	in_uint32_le(s, random_len);
530	in_uint32_le(s, rsa_info_len);
531
532	if (random_len != SEC_RANDOM_SIZE)
533	{
534	error("random len %d, expected %d\n", random_len, SEC_RANDOM_SIZE);
535	return False;
536	}
537
538	in_uint8p(s, *server_random, random_len);
539
540	/* RSA info */
541	end = s->p + rsa_info_len;
542	if (end > s->end)
543	return False;
544
545	in_uint32_le(s, flags); /* 1 = RDP4-style, 0x80000002 = X.509 */
546	if (flags & 1)
547	{
548	DEBUG_RDP5(("We're going for the RDP4-style encryption\n"));
549	in_uint8s(s, 8); /* unknown */
550
551	while (s->p < end)
552	{
553	in_uint16_le(s, tag);
554	in_uint16_le(s, length);
555
556	next_tag = s->p + length;
557
558	switch (tag)
559	{
560	case SEC_TAG_PUBKEY:
561	if (!sec_parse_public_key(s, modulus, exponent))
562	return False;
563	DEBUG_RDP5(("Got Public key, RDP4-style\n"));
564
565	break;
566
567	case SEC_TAG_KEYSIG:
568	if (!sec_parse_public_sig(s, length, modulus, exponent))
569	return False;
570	break;
571
572	default:
573	unimpl("crypt tag 0x%x\n", tag);
574	}
575
576	s->p = next_tag;
577	}
578	}
579	else
580	{
581	uint32 certcount;
582
583	DEBUG_RDP5(("We're going for the RDP5-style encryption\n"));
584	in_uint32_le(s, certcount); /* Number of certificates */
585	if (certcount < 2)
586	{
587	error("Server didn't send enough X509 certificates\n");
588	return False;
589	}
590	for (; certcount > 2; certcount--)
591	{ /* ignore all the certificates between the root and the signing CA */
592	uint32 ignorelen;
593	SSL_CERT *ignorecert;
594
595	DEBUG_RDP5(("Ignored certs left: %d\n", certcount));
596	in_uint32_le(s, ignorelen);
597	DEBUG_RDP5(("Ignored Certificate length is %d\n", ignorelen));
598	ignorecert = ssl_cert_read(s->p, ignorelen);
599	in_uint8s(s, ignorelen);
600	if (ignorecert == NULL)
601	{ /* XXX: error out? */
602	DEBUG_RDP5(("got a bad cert: this will probably screw up the rest of the communication\n"));
603	}
604
605	#ifdef WITH_DEBUG_RDP5
606	DEBUG_RDP5(("cert #%d (ignored):\n", certcount));
607	ssl_cert_print_fp(stdout, ignorecert);
608	#endif
609	}
610	/* Do da funky X.509 stuffy
611
612	"How did I find out about this? I looked up and saw a
613	bright light and when I came to I had a scar on my forehead
614	and knew about X.500"
615	- Peter Gutman in a early version of
616	http://www.cs.auckland.ac.nz/~pgut001/pubs/x509guide.txt
617	*/
618	in_uint32_le(s, cacert_len);
619	DEBUG_RDP5(("CA Certificate length is %d\n", cacert_len));
620	cacert = ssl_cert_read(s->p, cacert_len);
621	in_uint8s(s, cacert_len);
622	if (NULL == cacert)
623	{
624	error("Couldn't load CA Certificate from server\n");
625	return False;
626	}
627	in_uint32_le(s, cert_len);
628	DEBUG_RDP5(("Certificate length is %d\n", cert_len));
629	server_cert = ssl_cert_read(s->p, cert_len);
630	in_uint8s(s, cert_len);
631	if (NULL == server_cert)
632	{
633	ssl_cert_free(cacert);
634	error("Couldn't load Certificate from server\n");
635	return False;
636	}
637	if (!ssl_certs_ok(server_cert, cacert))
638	{
639	ssl_cert_free(server_cert);
640	ssl_cert_free(cacert);
641	error("Security error CA Certificate invalid\n");
642	return False;
643	}
644	ssl_cert_free(cacert);
645	in_uint8s(s, 16); /* Padding */
646	server_public_key = ssl_cert_to_rkey(server_cert, &g_server_public_key_len);
647	if (NULL == server_public_key)
648	{
649	DEBUG_RDP5(("Didn't parse X509 correctly\n"));
650	ssl_cert_free(server_cert);
651	return False;
652	}
653	ssl_cert_free(server_cert);
654	if ((g_server_public_key_len < SEC_MODULUS_SIZE) \|\|
655	(g_server_public_key_len > SEC_MAX_MODULUS_SIZE))
656	{
657	error("Bad server public key size (%u bits)\n",
658	g_server_public_key_len * 8);
659	ssl_rkey_free(server_public_key);
660	return False;
661	}
662	if (ssl_rkey_get_exp_mod(server_public_key, exponent, SEC_EXPONENT_SIZE,
663	modulus, SEC_MAX_MODULUS_SIZE) != 0)
664	{
665	error("Problem extracting RSA exponent, modulus");
666	ssl_rkey_free(server_public_key);
667	return False;
668	}
669	ssl_rkey_free(server_public_key);
670	return True; /* There's some garbage here we don't care about */
671	}
672	return s_check_end(s);
673	}
674
675	/* Process crypto information blob */
676	static void
677	sec_process_crypt_info(STREAM s)
678	{
679	uint8 *server_random = NULL;
680	uint8 client_random[SEC_RANDOM_SIZE];
681	uint8 modulus[SEC_MAX_MODULUS_SIZE];
682	uint8 exponent[SEC_EXPONENT_SIZE];
683	uint32 rc4_key_size;
684
685	memset(modulus, 0, sizeof(modulus));
686	memset(exponent, 0, sizeof(exponent));
687	if (!sec_parse_crypt_info(s, &rc4_key_size, &server_random, modulus, exponent))
688	{
689	DEBUG(("Failed to parse crypt info\n"));
690	return;
691	}
692	DEBUG(("Generating client random\n"));
693	generate_random(client_random);
694	sec_rsa_encrypt(g_sec_crypted_random, client_random, SEC_RANDOM_SIZE,
695	g_server_public_key_len, modulus, exponent);
696	sec_generate_keys(client_random, server_random, rc4_key_size);
697	}
698
699
700	/* Process SRV_INFO, find RDP version supported by server */
701	static void
702	sec_process_srv_info(STREAM s)
703	{
704	in_uint16_le(s, g_server_rdp_version);
705	DEBUG_RDP5(("Server RDP version is %d\n", g_server_rdp_version));
706	if (1 == g_server_rdp_version)
707	{
708	g_use_rdp5 = 0;
709	g_server_depth = 8;
710	}
711	}
712
713
714	/* Process connect response data blob */
715	void
716	sec_process_mcs_data(STREAM s)
717	{
718	uint16 tag, length;
719	uint8 *next_tag;
720	uint8 len;
721
722	in_uint8s(s, 21); /* header (T.124 ConferenceCreateResponse) */
723	in_uint8(s, len);
724	if (len & 0x80)
725	in_uint8(s, len);
726
727	while (s->p < s->end)
728	{
729	in_uint16_le(s, tag);
730	in_uint16_le(s, length);
731
732	if (length <= 4)
733	return;
734
735	next_tag = s->p + length - 4;
736
737	switch (tag)
738	{
739	case SEC_TAG_SRV_INFO:
740	sec_process_srv_info(s);
741	break;
742
743	case SEC_TAG_SRV_CRYPT:
744	sec_process_crypt_info(s);
745	break;
746
747	case SEC_TAG_SRV_CHANNELS:
748	/* FIXME: We should parse this information and
749	use it to map RDP5 channels to MCS
750	channels */
751	break;
752
753	default:
754	unimpl("response tag 0x%x\n", tag);
755	}
756
757	s->p = next_tag;
758	}
759	}
760
761	/* Receive secure transport packet */
762	STREAM
763	sec_recv(uint8 * rdpver)
764	{
765	uint32 sec_flags;
766	uint16 channel;
767	STREAM s;
768
769	while ((s = mcs_recv(&channel, rdpver)) != NULL)
770	{
771	if (rdpver != NULL)
772	{
773	if (*rdpver != 3)
774	{
775	if (*rdpver & 0x80)
776	{
777	in_uint8s(s, 8); /* signature */
778	sec_decrypt(s->p, s->end - s->p);
779	}
780	return s;
781	}
782	}
783	if (g_encryption \|\| !g_licence_issued)
784	{
785	in_uint32_le(s, sec_flags);
786
787	if (sec_flags & SEC_ENCRYPT)
788	{
789	in_uint8s(s, 8); /* signature */
790	sec_decrypt(s->p, s->end - s->p);
791	}
792
793	if (sec_flags & SEC_LICENCE_NEG)
794	{
795	licence_process(s);
796	continue;
797	}
798
799	if (sec_flags & 0x0400) /* SEC_REDIRECT_ENCRYPT */
800	{
801	uint8 swapbyte;
802
803	in_uint8s(s, 8); /* signature */
804	sec_decrypt(s->p, s->end - s->p);
805
806	/* Check for a redirect packet, starts with 00 04 */
807	if (s->p[0] == 0 && s->p[1] == 4)
808	{
809	/* for some reason the PDU and the length seem to be swapped.
810	This isn't good, but we're going to do a byte for byte
811	swap. So the first foure value appear as: 00 04 XX YY,
812	where XX YY is the little endian length. We're going to
813	use 04 00 as the PDU type, so after our swap this will look
814	like: XX YY 04 00 */
815	swapbyte = s->p[0];
816	s->p[0] = s->p[2];
817	s->p[2] = swapbyte;
818
819	swapbyte = s->p[1];
820	s->p[1] = s->p[3];
821	s->p[3] = swapbyte;
822
823	swapbyte = s->p[2];
824	s->p[2] = s->p[3];
825	s->p[3] = swapbyte;
826	}
827	#ifdef WITH_DEBUG
828	/* warning! this debug statement will show passwords in the clear! */
829	hexdump(s->p, s->end - s->p);
830	#endif
831	}
832
833	}
834
835	if (channel != MCS_GLOBAL_CHANNEL)
836	{
837	channel_process(s, channel);
838	*rdpver = 0xff;
839	return s;
840	}
841
842	return s;
843	}
844
845	return NULL;
846	}
847
848	/* Establish a secure connection */
849	RD_BOOL
850	sec_connect(char server, char username)
851	{
852	struct stream mcs_data;
853
854	/* We exchange some RDP data during the MCS-Connect */
855	mcs_data.size = 512;
856	mcs_data.p = mcs_data.data = (uint8 *) xmalloc(mcs_data.size);
857	sec_out_mcs_data(&mcs_data);
858
859	if (!mcs_connect(server, &mcs_data, username))
860	return False;
861
862	/* sec_process_mcs_data(&mcs_data); */
863	if (g_encryption)
864	sec_establish_key();
865	xfree(mcs_data.data);
866	return True;
867	}
868
869	/* Establish a secure connection */
870	RD_BOOL
871	sec_reconnect(char *server)
872	{
873	struct stream mcs_data;
874
875	/* We exchange some RDP data during the MCS-Connect */
876	mcs_data.size = 512;
877	mcs_data.p = mcs_data.data = (uint8 *) xmalloc(mcs_data.size);
878	sec_out_mcs_data(&mcs_data);
879
880	if (!mcs_reconnect(server, &mcs_data))
881	return False;
882
883	/* sec_process_mcs_data(&mcs_data); */
884	if (g_encryption)
885	sec_establish_key();
886	xfree(mcs_data.data);
887	return True;
888	}
889
890	/* Disconnect a connection */
891	void
892	sec_disconnect(void)
893	{
894	mcs_disconnect();
895	}
896
897	/* reset the state of the sec layer */
898	void
899	sec_reset_state(void)
900	{
901	g_server_rdp_version = 0;
902	g_sec_encrypt_use_count = 0;
903	g_sec_decrypt_use_count = 0;
904	mcs_reset_state();
905	}

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source: vbox/trunk/src/VBox/RDP/client/secure.c@ 11982

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