secure.c@ 61547

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rdesktop 1.8.3 modified for VBox
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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 <matthewc.unsw.edu.au> 1999-2008
5	Copyright 2005-2011 Peter Astrand <[email protected]> for Cendio AB
6
7	This program is free software: you can redistribute it and/or modify
8	it under the terms of the GNU General Public License as published by
9	the Free Software Foundation, either version 3 of the License, or
10	(at your option) any later version.
11
12	This program is distributed in the hope that it will be useful,
13	but WITHOUT ANY WARRANTY; without even the implied warranty of
14	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15	GNU General Public License for more details.
16
17	You should have received a copy of the GNU General Public License
18	along with this program. If not, see <http://www.gnu.org/licenses/>.
19	*/
20
21	/*
22	* Oracle 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, Oracle 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_licence_error_result;
43	extern RDP_VERSION g_rdp_version;
44	extern RD_BOOL g_console_session;
45	extern uint32 g_redirect_session_id;
46	extern int g_server_depth;
47	extern VCHANNEL g_channels[];
48	extern unsigned int g_num_channels;
49	extern uint8 g_client_random[SEC_RANDOM_SIZE];
50
51	static int g_rc4_key_len;
52	static RDSSL_RC4 g_rc4_decrypt_key;
53	static RDSSL_RC4 g_rc4_encrypt_key;
54	static uint32 g_server_public_key_len;
55
56	static uint8 g_sec_sign_key[16];
57	static uint8 g_sec_decrypt_key[16];
58	static uint8 g_sec_encrypt_key[16];
59	static uint8 g_sec_decrypt_update_key[16];
60	static uint8 g_sec_encrypt_update_key[16];
61	static uint8 g_sec_crypted_random[SEC_MAX_MODULUS_SIZE];
62
63	uint16 g_server_rdp_version = 0;
64
65	/* These values must be available to reset state - Session Directory */
66	static int g_sec_encrypt_use_count = 0;
67	static int g_sec_decrypt_use_count = 0;
68
69	/*
70	* I believe this is based on SSLv3 with the following differences:
71	* MAC algorithm (5.2.3.1) uses only 32-bit length in place of seq_num/type/length fields
72	* MAC algorithm uses SHA1 and MD5 for the two hash functions instead of one or other
73	* key_block algorithm (6.2.2) uses 'X', 'YY', 'ZZZ' instead of 'A', 'BB', 'CCC'
74	* key_block partitioning is different (16 bytes each: MAC secret, decrypt key, encrypt key)
75	* encryption/decryption keys updated every 4096 packets
76	* See http://wp.netscape.com/eng/ssl3/draft302.txt
77	*/
78
79	/*
80	* 48-byte transformation used to generate master secret (6.1) and key material (6.2.2).
81	* Both SHA1 and MD5 algorithms are used.
82	*/
83	void
84	sec_hash_48(uint8 * out, uint8 * in, uint8 * salt1, uint8 * salt2, uint8 salt)
85	{
86	uint8 shasig[20];
87	uint8 pad[4];
88	RDSSL_SHA1 sha1;
89	RDSSL_MD5 md5;
90	int i;
91
92	for (i = 0; i < 3; i++)
93	{
94	memset(pad, salt + i, i + 1);
95
96	rdssl_sha1_init(&sha1);
97	rdssl_sha1_update(&sha1, pad, i + 1);
98	rdssl_sha1_update(&sha1, in, 48);
99	rdssl_sha1_update(&sha1, salt1, 32);
100	rdssl_sha1_update(&sha1, salt2, 32);
101	rdssl_sha1_final(&sha1, shasig);
102
103	rdssl_md5_init(&md5);
104	rdssl_md5_update(&md5, in, 48);
105	rdssl_md5_update(&md5, shasig, 20);
106	rdssl_md5_final(&md5, &out[i * 16]);
107	}
108	}
109
110	/*
111	* 16-byte transformation used to generate export keys (6.2.2).
112	*/
113	void
114	sec_hash_16(uint8 * out, uint8 * in, uint8 * salt1, uint8 * salt2)
115	{
116	RDSSL_MD5 md5;
117
118	rdssl_md5_init(&md5);
119	rdssl_md5_update(&md5, in, 16);
120	rdssl_md5_update(&md5, salt1, 32);
121	rdssl_md5_update(&md5, salt2, 32);
122	rdssl_md5_final(&md5, out);
123	}
124
125	/*
126	* 16-byte sha1 hash
127	*/
128	void
129	sec_hash_sha1_16(uint8 * out, uint8 * in, uint8 * salt1)
130	{
131	RDSSL_SHA1 sha1;
132	rdssl_sha1_init(&sha1);
133	rdssl_sha1_update(&sha1, in, 16);
134	rdssl_sha1_update(&sha1, salt1, 16);
135	rdssl_sha1_final(&sha1, out);
136	}
137
138	/* create string from hash */
139	void
140	sec_hash_to_string(char out, int out_size, uint8 in, int in_size)
141	{
142	int k;
143	memset(out, 0, out_size);
144	for (k = 0; k < in_size; k++, out += 2)
145	{
146	sprintf(out, "%.2x", in[k]);
147	}
148	}
149
150	/* Reduce key entropy from 64 to 40 bits */
151	static void
152	sec_make_40bit(uint8 * key)
153	{
154	key[0] = 0xd1;
155	key[1] = 0x26;
156	key[2] = 0x9e;
157	}
158
159	/* Generate encryption keys given client and server randoms */
160	static void
161	sec_generate_keys(uint8 * client_random, uint8 * server_random, int rc4_key_size)
162	{
163	uint8 pre_master_secret[48];
164	uint8 master_secret[48];
165	uint8 key_block[48];
166
167	/* Construct pre-master secret */
168	memcpy(pre_master_secret, client_random, 24);
169	memcpy(pre_master_secret + 24, server_random, 24);
170
171	/* Generate master secret and then key material */
172	sec_hash_48(master_secret, pre_master_secret, client_random, server_random, 'A');
173	sec_hash_48(key_block, master_secret, client_random, server_random, 'X');
174
175	/* First 16 bytes of key material is MAC secret */
176	memcpy(g_sec_sign_key, key_block, 16);
177
178	/* Generate export keys from next two blocks of 16 bytes */
179	sec_hash_16(g_sec_decrypt_key, &key_block[16], client_random, server_random);
180	sec_hash_16(g_sec_encrypt_key, &key_block[32], client_random, server_random);
181
182	if (rc4_key_size == 1)
183	{
184	DEBUG(("40-bit encryption enabled\n"));
185	sec_make_40bit(g_sec_sign_key);
186	sec_make_40bit(g_sec_decrypt_key);
187	sec_make_40bit(g_sec_encrypt_key);
188	g_rc4_key_len = 8;
189	}
190	else
191	{
192	DEBUG(("rc_4_key_size == %d, 128-bit encryption enabled\n", rc4_key_size));
193	g_rc4_key_len = 16;
194	}
195
196	/* Save initial RC4 keys as update keys */
197	memcpy(g_sec_decrypt_update_key, g_sec_decrypt_key, 16);
198	memcpy(g_sec_encrypt_update_key, g_sec_encrypt_key, 16);
199
200	/* Initialise RC4 state arrays */
201	rdssl_rc4_set_key(&g_rc4_decrypt_key, g_sec_decrypt_key, g_rc4_key_len);
202	rdssl_rc4_set_key(&g_rc4_encrypt_key, g_sec_encrypt_key, g_rc4_key_len);
203	}
204
205	static uint8 pad_54[40] = {
206	54, 54, 54, 54, 54, 54, 54, 54, 54, 54, 54, 54, 54, 54, 54, 54, 54,
207	54, 54, 54,
208	54, 54, 54, 54, 54, 54, 54, 54, 54, 54, 54, 54, 54, 54, 54, 54, 54,
209	54, 54, 54
210	};
211
212	static uint8 pad_92[48] = {
213	92, 92, 92, 92, 92, 92, 92, 92, 92, 92, 92, 92, 92, 92, 92, 92, 92,
214	92, 92, 92, 92, 92, 92, 92,
215	92, 92, 92, 92, 92, 92, 92, 92, 92, 92, 92, 92, 92, 92, 92, 92, 92,
216	92, 92, 92, 92, 92, 92, 92
217	};
218
219	/* Output a uint32 into a buffer (little-endian) */
220	void
221	buf_out_uint32(uint8 * buffer, uint32 value)
222	{
223	buffer[0] = (value) & 0xff;
224	buffer[1] = (value >> 8) & 0xff;
225	buffer[2] = (value >> 16) & 0xff;
226	buffer[3] = (value >> 24) & 0xff;
227	}
228
229	/* Generate a MAC hash (5.2.3.1), using a combination of SHA1 and MD5 */
230	void
231	sec_sign(uint8 * signature, int siglen, uint8 * session_key, int keylen, uint8 * data, int datalen)
232	{
233	uint8 shasig[20];
234	uint8 md5sig[16];
235	uint8 lenhdr[4];
236	RDSSL_SHA1 sha1;
237	RDSSL_MD5 md5;
238
239	buf_out_uint32(lenhdr, datalen);
240
241	rdssl_sha1_init(&sha1);
242	rdssl_sha1_update(&sha1, session_key, keylen);
243	rdssl_sha1_update(&sha1, pad_54, 40);
244	rdssl_sha1_update(&sha1, lenhdr, 4);
245	rdssl_sha1_update(&sha1, data, datalen);
246	rdssl_sha1_final(&sha1, shasig);
247
248	rdssl_md5_init(&md5);
249	rdssl_md5_update(&md5, session_key, keylen);
250	rdssl_md5_update(&md5, pad_92, 48);
251	rdssl_md5_update(&md5, shasig, 20);
252	rdssl_md5_final(&md5, md5sig);
253
254	memcpy(signature, md5sig, siglen);
255	}
256
257	/* Update an encryption key */
258	static void
259	sec_update(uint8 * key, uint8 * update_key)
260	{
261	uint8 shasig[20];
262	RDSSL_SHA1 sha1;
263	RDSSL_MD5 md5;
264	RDSSL_RC4 update;
265
266	rdssl_sha1_init(&sha1);
267	rdssl_sha1_update(&sha1, update_key, g_rc4_key_len);
268	rdssl_sha1_update(&sha1, pad_54, 40);
269	rdssl_sha1_update(&sha1, key, g_rc4_key_len);
270	rdssl_sha1_final(&sha1, shasig);
271
272	rdssl_md5_init(&md5);
273	rdssl_md5_update(&md5, update_key, g_rc4_key_len);
274	rdssl_md5_update(&md5, pad_92, 48);
275	rdssl_md5_update(&md5, shasig, 20);
276	rdssl_md5_final(&md5, key);
277
278	rdssl_rc4_set_key(&update, key, g_rc4_key_len);
279	rdssl_rc4_crypt(&update, key, key, g_rc4_key_len);
280
281	if (g_rc4_key_len == 8)
282	sec_make_40bit(key);
283	}
284
285	/* Encrypt data using RC4 */
286	static void
287	sec_encrypt(uint8 * data, int length)
288	{
289	if (g_sec_encrypt_use_count == 4096)
290	{
291	sec_update(g_sec_encrypt_key, g_sec_encrypt_update_key);
292	rdssl_rc4_set_key(&g_rc4_encrypt_key, g_sec_encrypt_key, g_rc4_key_len);
293	g_sec_encrypt_use_count = 0;
294	}
295
296	rdssl_rc4_crypt(&g_rc4_encrypt_key, data, data, length);
297	g_sec_encrypt_use_count++;
298	}
299
300	/* Decrypt data using RC4 */
301	void
302	sec_decrypt(uint8 * data, int length)
303	{
304	if (g_sec_decrypt_use_count == 4096)
305	{
306	sec_update(g_sec_decrypt_key, g_sec_decrypt_update_key);
307	rdssl_rc4_set_key(&g_rc4_decrypt_key, g_sec_decrypt_key, g_rc4_key_len);
308	g_sec_decrypt_use_count = 0;
309	}
310
311	rdssl_rc4_crypt(&g_rc4_decrypt_key, data, data, length);
312	g_sec_decrypt_use_count++;
313	}
314
315	/* Perform an RSA public key encryption operation */
316	static void
317	sec_rsa_encrypt(uint8 * out, uint8 * in, int len, uint32 modulus_size, uint8 * modulus,
318	uint8 * exponent)
319	{
320	rdssl_rsa_encrypt(out, in, len, modulus_size, modulus, exponent);
321	}
322
323	/* Initialise secure transport packet */
324	STREAM
325	sec_init(uint32 flags, int maxlen)
326	{
327	int hdrlen;
328	STREAM s;
329
330	if (!g_licence_issued && !g_licence_error_result)
331	hdrlen = (flags & SEC_ENCRYPT) ? 12 : 4;
332	else
333	hdrlen = (flags & SEC_ENCRYPT) ? 12 : 0;
334	s = mcs_init(maxlen + hdrlen);
335	s_push_layer(s, sec_hdr, hdrlen);
336
337	return s;
338	}
339
340	/* Transmit secure transport packet over specified channel */
341	void
342	sec_send_to_channel(STREAM s, uint32 flags, uint16 channel)
343	{
344	int datalen;
345
346	#ifdef WITH_SCARD
347	scard_lock(SCARD_LOCK_SEC);
348	#endif
349
350	s_pop_layer(s, sec_hdr);
351	if ((!g_licence_issued && !g_licence_error_result) \|\| (flags & SEC_ENCRYPT))
352	out_uint32_le(s, flags);
353
354	if (flags & SEC_ENCRYPT)
355	{
356	flags &= ~SEC_ENCRYPT;
357	datalen = s->end - s->p - 8;
358
359	#if WITH_DEBUG
360	DEBUG(("Sending encrypted packet:\n"));
361	hexdump(s->p + 8, datalen);
362	#endif
363
364	sec_sign(s->p, 8, g_sec_sign_key, g_rc4_key_len, s->p + 8, datalen);
365	sec_encrypt(s->p + 8, datalen);
366	}
367
368	mcs_send_to_channel(s, channel);
369
370	#ifdef WITH_SCARD
371	scard_unlock(SCARD_LOCK_SEC);
372	#endif
373	}
374
375	/* Transmit secure transport packet */
376
377	void
378	sec_send(STREAM s, uint32 flags)
379	{
380	sec_send_to_channel(s, flags, MCS_GLOBAL_CHANNEL);
381	}
382
383
384	/* Transfer the client random to the server */
385	static void
386	sec_establish_key(void)
387	{
388	uint32 length = g_server_public_key_len + SEC_PADDING_SIZE;
389	uint32 flags = SEC_CLIENT_RANDOM;
390	STREAM s;
391
392	s = sec_init(flags, length + 4);
393
394	out_uint32_le(s, length);
395	out_uint8p(s, g_sec_crypted_random, g_server_public_key_len);
396	out_uint8s(s, SEC_PADDING_SIZE);
397
398	s_mark_end(s);
399	sec_send(s, flags);
400	}
401
402	/* Output connect initial data blob */
403	static void
404	sec_out_mcs_data(STREAM s, uint32 selected_protocol)
405	{
406	int hostlen = 2 * strlen(g_hostname);
407	int length = 162 + 76 + 12 + 4;
408	unsigned int i;
409
410	if (g_num_channels > 0)
411	length += g_num_channels * 12 + 8;
412
413	if (hostlen > 30)
414	hostlen = 30;
415
416	/* Generic Conference Control (T.124) ConferenceCreateRequest */
417	out_uint16_be(s, 5);
418	out_uint16_be(s, 0x14);
419	out_uint8(s, 0x7c);
420	out_uint16_be(s, 1);
421
422	out_uint16_be(s, (length \| 0x8000)); /* remaining length */
423
424	out_uint16_be(s, 8); /* length? */
425	out_uint16_be(s, 16);
426	out_uint8(s, 0);
427	out_uint16_le(s, 0xc001);
428	out_uint8(s, 0);
429
430	out_uint32_le(s, 0x61637544); /* OEM ID: "Duca", as in Ducati. */
431	out_uint16_be(s, ((length - 14) \| 0x8000)); /* remaining length */
432
433	/* Client information */
434	out_uint16_le(s, SEC_TAG_CLI_INFO);
435	out_uint16_le(s, 216); /* length */
436	out_uint16_le(s, (g_rdp_version >= RDP_V5) ? 4 : 1); /* RDP version. 1 == RDP4, 4 >= RDP5 to RDP8 */
437	out_uint16_le(s, 8);
438	out_uint16_le(s, g_width);
439	out_uint16_le(s, g_height);
440	out_uint16_le(s, 0xca01);
441	out_uint16_le(s, 0xaa03);
442	out_uint32_le(s, g_keylayout);
443	out_uint32_le(s, 2600); /* Client build. We are now 2600 compatible :-) */
444
445	/* Unicode name of client, padded to 32 bytes */
446	rdp_out_unistr(s, g_hostname, hostlen);
447	out_uint8s(s, 30 - hostlen);
448
449	/* See
450	http://msdn.microsoft.com/library/default.asp?url=/library/en-us/wceddk40/html/cxtsksupportingremotedesktopprotocol.asp */
451	out_uint32_le(s, g_keyboard_type);
452	out_uint32_le(s, g_keyboard_subtype);
453	out_uint32_le(s, g_keyboard_functionkeys);
454	out_uint8s(s, 64); /* reserved? 4 + 12 doublewords */
455	out_uint16_le(s, 0xca01); /* colour depth? */
456	out_uint16_le(s, 1);
457
458	out_uint32(s, 0);
459	out_uint8(s, g_server_depth);
460	out_uint16_le(s, 0x0700);
461	out_uint8(s, 0);
462	out_uint32_le(s, 1);
463	out_uint8s(s, 64);
464	out_uint32_le(s, selected_protocol); /* End of client info */
465
466	/* Write a Client Cluster Data (TS_UD_CS_CLUSTER) */
467	uint32 cluster_flags = 0;
468	out_uint16_le(s, SEC_TAG_CLI_CLUSTER); /* header.type */
469	out_uint16_le(s, 12); /* length */
470
471	cluster_flags \|= SEC_CC_REDIRECTION_SUPPORTED;
472	cluster_flags \|= (SEC_CC_REDIRECT_VERSION_3 << 2);
473
474	if (g_console_session \|\| g_redirect_session_id != 0)
475	cluster_flags \|= SEC_CC_REDIRECT_SESSIONID_FIELD_VALID;
476
477	out_uint32_le(s, cluster_flags);
478	out_uint32(s, g_redirect_session_id);
479
480	/* Client encryption settings */
481	out_uint16_le(s, SEC_TAG_CLI_CRYPT);
482	out_uint16_le(s, 12); /* length */
483	out_uint32_le(s, g_encryption ? 0x3 : 0); /* encryption supported, 128-bit supported */
484	out_uint32(s, 0); /* Unknown */
485
486	DEBUG_RDP5(("g_num_channels is %d\n", g_num_channels));
487	if (g_num_channels > 0)
488	{
489	out_uint16_le(s, SEC_TAG_CLI_CHANNELS);
490	out_uint16_le(s, g_num_channels * 12 + 8); /* length */
491	out_uint32_le(s, g_num_channels); /* number of virtual channels */
492	for (i = 0; i < g_num_channels; i++)
493	{
494	DEBUG_RDP5(("Requesting channel %s\n", g_channels[i].name));
495	out_uint8a(s, g_channels[i].name, 8);
496	out_uint32_be(s, g_channels[i].flags);
497	}
498	}
499
500	s_mark_end(s);
501	}
502
503	/* Parse a public key structure */
504	static RD_BOOL
505	sec_parse_public_key(STREAM s, uint8 * modulus, uint8 * exponent)
506	{
507	uint32 magic, modulus_len;
508
509	in_uint32_le(s, magic);
510	if (magic != SEC_RSA_MAGIC)
511	{
512	error("RSA magic 0x%x\n", magic);
513	return False;
514	}
515
516	in_uint32_le(s, modulus_len);
517	modulus_len -= SEC_PADDING_SIZE;
518	if ((modulus_len < SEC_MODULUS_SIZE) \|\| (modulus_len > SEC_MAX_MODULUS_SIZE))
519	{
520	error("Bad server public key size (%u bits)\n", modulus_len * 8);
521	return False;
522	}
523
524	in_uint8s(s, 8); /* modulus_bits, unknown */
525	in_uint8a(s, exponent, SEC_EXPONENT_SIZE);
526	in_uint8a(s, modulus, modulus_len);
527	in_uint8s(s, SEC_PADDING_SIZE);
528	g_server_public_key_len = modulus_len;
529
530	return s_check(s);
531	}
532
533	/* Parse a public signature structure */
534	static RD_BOOL
535	sec_parse_public_sig(STREAM s, uint32 len, uint8 * modulus, uint8 * exponent)
536	{
537	uint8 signature[SEC_MAX_MODULUS_SIZE];
538	uint32 sig_len;
539
540	if (len != 72)
541	{
542	return True;
543	}
544	memset(signature, 0, sizeof(signature));
545	sig_len = len - 8;
546	in_uint8a(s, signature, sig_len);
547	return rdssl_sig_ok(exponent, SEC_EXPONENT_SIZE, modulus, g_server_public_key_len,
548	signature, sig_len);
549	}
550
551	/* Parse a crypto information structure */
552	static RD_BOOL
553	sec_parse_crypt_info(STREAM s, uint32 * rc4_key_size,
554	uint8 ** server_random, uint8 * modulus, uint8 * exponent)
555	{
556	uint32 crypt_level, random_len, rsa_info_len;
557	uint32 cacert_len, cert_len, flags;
558	RDSSL_CERT cacert, server_cert;
559	RDSSL_RKEY *server_public_key;
560	uint16 tag, length;
561	uint8 next_tag, end;
562
563	in_uint32_le(s, rc4_key_size); / 1 = 40-bit, 2 = 128-bit */
564	in_uint32_le(s, crypt_level); /* 1 = low, 2 = medium, 3 = high */
565	if (crypt_level == 0)
566	{
567	/* no encryption */
568	return False;
569	}
570
571	in_uint32_le(s, random_len);
572	in_uint32_le(s, rsa_info_len);
573
574	if (random_len != SEC_RANDOM_SIZE)
575	{
576	error("random len %d, expected %d\n", random_len, SEC_RANDOM_SIZE);
577	return False;
578	}
579
580	in_uint8p(s, *server_random, random_len);
581
582	/* RSA info */
583	end = s->p + rsa_info_len;
584	if (end > s->end)
585	return False;
586
587	in_uint32_le(s, flags); /* 1 = RDP4-style, 0x80000002 = X.509 */
588	if (flags & 1)
589	{
590	DEBUG_RDP5(("We're going for the RDP4-style encryption\n"));
591	in_uint8s(s, 8); /* unknown */
592
593	while (s->p < end)
594	{
595	in_uint16_le(s, tag);
596	in_uint16_le(s, length);
597
598	next_tag = s->p + length;
599
600	switch (tag)
601	{
602	case SEC_TAG_PUBKEY:
603	if (!sec_parse_public_key(s, modulus, exponent))
604	return False;
605	DEBUG_RDP5(("Got Public key, RDP4-style\n"));
606
607	break;
608
609	case SEC_TAG_KEYSIG:
610	if (!sec_parse_public_sig(s, length, modulus, exponent))
611	return False;
612	break;
613
614	default:
615	unimpl("crypt tag 0x%x\n", tag);
616	}
617
618	s->p = next_tag;
619	}
620	}
621	else
622	{
623	uint32 certcount;
624
625	DEBUG_RDP5(("We're going for the RDP5-style encryption\n"));
626	in_uint32_le(s, certcount); /* Number of certificates */
627	if (certcount < 2)
628	{
629	error("Server didn't send enough X509 certificates\n");
630	return False;
631	}
632	for (; certcount > 2; certcount--)
633	{ /* ignore all the certificates between the root and the signing CA */
634	uint32 ignorelen;
635	RDSSL_CERT *ignorecert;
636
637	DEBUG_RDP5(("Ignored certs left: %d\n", certcount));
638	in_uint32_le(s, ignorelen);
639	DEBUG_RDP5(("Ignored Certificate length is %d\n", ignorelen));
640	ignorecert = rdssl_cert_read(s->p, ignorelen);
641	in_uint8s(s, ignorelen);
642	if (ignorecert == NULL)
643	{ /* XXX: error out? */
644	DEBUG_RDP5(("got a bad cert: this will probably screw up the rest of the communication\n"));
645	}
646
647	#ifdef WITH_DEBUG_RDP5
648	DEBUG_RDP5(("cert #%d (ignored):\n", certcount));
649	rdssl_cert_print_fp(stdout, ignorecert);
650	#endif
651	}
652	/* Do da funky X.509 stuffy
653
654	"How did I find out about this? I looked up and saw a
655	bright light and when I came to I had a scar on my forehead
656	and knew about X.500"
657	- Peter Gutman in a early version of
658	http://www.cs.auckland.ac.nz/~pgut001/pubs/x509guide.txt
659	*/
660	in_uint32_le(s, cacert_len);
661	DEBUG_RDP5(("CA Certificate length is %d\n", cacert_len));
662	cacert = rdssl_cert_read(s->p, cacert_len);
663	in_uint8s(s, cacert_len);
664	if (NULL == cacert)
665	{
666	error("Couldn't load CA Certificate from server\n");
667	return False;
668	}
669	in_uint32_le(s, cert_len);
670	DEBUG_RDP5(("Certificate length is %d\n", cert_len));
671	server_cert = rdssl_cert_read(s->p, cert_len);
672	in_uint8s(s, cert_len);
673	if (NULL == server_cert)
674	{
675	rdssl_cert_free(cacert);
676	error("Couldn't load Certificate from server\n");
677	return False;
678	}
679	if (!rdssl_certs_ok(server_cert, cacert))
680	{
681	rdssl_cert_free(server_cert);
682	rdssl_cert_free(cacert);
683	error("Security error CA Certificate invalid\n");
684	return False;
685	}
686	rdssl_cert_free(cacert);
687	in_uint8s(s, 16); /* Padding */
688	server_public_key = rdssl_cert_to_rkey(server_cert, &g_server_public_key_len);
689	if (NULL == server_public_key)
690	{
691	DEBUG_RDP5(("Didn't parse X509 correctly\n"));
692	rdssl_cert_free(server_cert);
693	return False;
694	}
695	rdssl_cert_free(server_cert);
696	if ((g_server_public_key_len < SEC_MODULUS_SIZE) \|\|
697	(g_server_public_key_len > SEC_MAX_MODULUS_SIZE))
698	{
699	error("Bad server public key size (%u bits)\n",
700	g_server_public_key_len * 8);
701	rdssl_rkey_free(server_public_key);
702	return False;
703	}
704	if (rdssl_rkey_get_exp_mod(server_public_key, exponent, SEC_EXPONENT_SIZE,
705	modulus, SEC_MAX_MODULUS_SIZE) != 0)
706	{
707	error("Problem extracting RSA exponent, modulus");
708	rdssl_rkey_free(server_public_key);
709	return False;
710	}
711	rdssl_rkey_free(server_public_key);
712	return True; /* There's some garbage here we don't care about */
713	}
714	return s_check_end(s);
715	}
716
717	/* Process crypto information blob */
718	static void
719	sec_process_crypt_info(STREAM s)
720	{
721	uint8 *server_random = NULL;
722	uint8 modulus[SEC_MAX_MODULUS_SIZE];
723	uint8 exponent[SEC_EXPONENT_SIZE];
724	uint32 rc4_key_size;
725
726	memset(modulus, 0, sizeof(modulus));
727	memset(exponent, 0, sizeof(exponent));
728	if (!sec_parse_crypt_info(s, &rc4_key_size, &server_random, modulus, exponent))
729	{
730	DEBUG(("Failed to parse crypt info\n"));
731	return;
732	}
733	DEBUG(("Generating client random\n"));
734	generate_random(g_client_random);
735	sec_rsa_encrypt(g_sec_crypted_random, g_client_random, SEC_RANDOM_SIZE,
736	g_server_public_key_len, modulus, exponent);
737	sec_generate_keys(g_client_random, server_random, rc4_key_size);
738	}
739
740
741	/* Process SRV_INFO, find RDP version supported by server */
742	static void
743	sec_process_srv_info(STREAM s)
744	{
745	in_uint16_le(s, g_server_rdp_version);
746	DEBUG_RDP5(("Server RDP version is %d\n", g_server_rdp_version));
747	if (1 == g_server_rdp_version)
748	{
749	g_rdp_version = RDP_V4;
750	g_server_depth = 8;
751	}
752	}
753
754
755	/* Process connect response data blob */
756	void
757	sec_process_mcs_data(STREAM s)
758	{
759	uint16 tag, length;
760	uint8 *next_tag;
761	uint8 len;
762
763	in_uint8s(s, 21); /* header (T.124 ConferenceCreateResponse) */
764	in_uint8(s, len);
765	if (len & 0x80)
766	in_uint8(s, len);
767
768	while (s->p < s->end)
769	{
770	in_uint16_le(s, tag);
771	in_uint16_le(s, length);
772
773	if (length <= 4)
774	return;
775
776	next_tag = s->p + length - 4;
777
778	switch (tag)
779	{
780	case SEC_TAG_SRV_INFO:
781	sec_process_srv_info(s);
782	break;
783
784	case SEC_TAG_SRV_CRYPT:
785	sec_process_crypt_info(s);
786	break;
787
788	case SEC_TAG_SRV_CHANNELS:
789	/* FIXME: We should parse this information and
790	use it to map RDP5 channels to MCS
791	channels */
792	break;
793
794	default:
795	unimpl("response tag 0x%x\n", tag);
796	}
797
798	s->p = next_tag;
799	}
800	}
801
802	/* Receive secure transport packet */
803	STREAM
804	sec_recv(uint8 * rdpver)
805	{
806	uint32 sec_flags;
807	uint16 channel;
808	STREAM s;
809
810	while ((s = mcs_recv(&channel, rdpver)) != NULL)
811	{
812	if (rdpver != NULL)
813	{
814	if (*rdpver != 3)
815	{
816	if (*rdpver & 0x80)
817	{
818	in_uint8s(s, 8); /* signature */
819	sec_decrypt(s->p, s->end - s->p);
820	}
821	return s;
822	}
823	}
824	if (g_encryption \|\| (!g_licence_issued && !g_licence_error_result))
825	{
826	in_uint32_le(s, sec_flags);
827
828	if (g_encryption)
829	{
830	if (sec_flags & SEC_ENCRYPT)
831	{
832	in_uint8s(s, 8); /* signature */
833	sec_decrypt(s->p, s->end - s->p);
834	}
835
836	if (sec_flags & SEC_LICENCE_NEG)
837	{
838	licence_process(s);
839	continue;
840	}
841
842	if (sec_flags & 0x0400) /* SEC_REDIRECT_ENCRYPT */
843	{
844	uint8 swapbyte;
845
846	in_uint8s(s, 8); /* signature */
847	sec_decrypt(s->p, s->end - s->p);
848
849	/* Check for a redirect packet, starts with 00 04 */
850	if (s->p[0] == 0 && s->p[1] == 4)
851	{
852	/* for some reason the PDU and the length seem to be swapped.
853	This isn't good, but we're going to do a byte for byte
854	swap. So the first foure value appear as: 00 04 XX YY,
855	where XX YY is the little endian length. We're going to
856	use 04 00 as the PDU type, so after our swap this will look
857	like: XX YY 04 00 */
858	swapbyte = s->p[0];
859	s->p[0] = s->p[2];
860	s->p[2] = swapbyte;
861
862	swapbyte = s->p[1];
863	s->p[1] = s->p[3];
864	s->p[3] = swapbyte;
865
866	swapbyte = s->p[2];
867	s->p[2] = s->p[3];
868	s->p[3] = swapbyte;
869	}
870	#ifdef WITH_DEBUG
871	/* warning! this debug statement will show passwords in the clear! */
872	hexdump(s->p, s->end - s->p);
873	#endif
874	}
875	}
876	else
877	{
878	if ((sec_flags & 0xffff) == SEC_LICENCE_NEG)
879	{
880	licence_process(s);
881	continue;
882	}
883	s->p -= 4;
884	}
885	}
886
887	if (channel != MCS_GLOBAL_CHANNEL)
888	{
889	channel_process(s, channel);
890	if (rdpver != NULL)
891	*rdpver = 0xff;
892	return s;
893	}
894
895	return s;
896	}
897
898	return NULL;
899	}
900
901	/* Establish a secure connection */
902	RD_BOOL
903	sec_connect(char server, char username, char domain, char password, RD_BOOL reconnect)
904	{
905	uint32 selected_proto;
906	struct stream mcs_data;
907
908	/* Start a MCS connect sequence */
909	if (!mcs_connect_start(server, username, domain, password, reconnect, &selected_proto))
910	return False;
911
912	/* We exchange some RDP data during the MCS-Connect */
913	mcs_data.size = 512;
914	mcs_data.p = mcs_data.data = (uint8 *) xmalloc(mcs_data.size);
915	sec_out_mcs_data(&mcs_data, selected_proto);
916
917	/* finialize the MCS connect sequence */
918	if (!mcs_connect_finalize(&mcs_data))
919	return False;
920
921	/* sec_process_mcs_data(&mcs_data); */
922	if (g_encryption)
923	sec_establish_key();
924	xfree(mcs_data.data);
925	return True;
926	}
927
928	/* Disconnect a connection */
929	void
930	sec_disconnect(void)
931	{
932	mcs_disconnect();
933	}
934
935	/* reset the state of the sec layer */
936	void
937	sec_reset_state(void)
938	{
939	g_server_rdp_version = 0;
940	g_sec_encrypt_use_count = 0;
941	g_sec_decrypt_use_count = 0;
942	g_licence_issued = 0;
943	g_licence_error_result = 0;
944	mcs_reset_state();
945	}

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source: vbox/trunk/src/VBox/RDP/client-1.8.3/secure.c@ 61547

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