trunk/rdesktop/licence.c

/*
   rdesktop: A Remote Desktop Protocol client.
   RDP licensing negotiation
   Copyright (C) Matthew Chapman 1999-2002
   
   This program is free software; you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation; either version 2 of the License, or
   (at your option) any later version.

   This program is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU General Public License for more details.
   
   You should have received a copy of the GNU General Public License
   along with this program; if not, write to the Free Software
   Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*/

#include "rdesktop.h"

#ifdef WITH_OPENSSL
#include <openssl/rc4.h>
#else
#include "crypto/rc4.h"
#endif

extern char username[16];
extern char hostname[16];

static uint8 licence_key[16];
static uint8 licence_sign_key[16];

BOOL licence_issued = False;

/* Generate a session key and RC4 keys, given client and server randoms */
static void
licence_generate_keys(uint8 * client_key, uint8 * server_key, uint8 * client_rsa)
{
        uint8 session_key[48];
        uint8 temp_hash[48];

        /* Generate session key - two rounds of sec_hash_48 */
        sec_hash_48(temp_hash, client_rsa, client_key, server_key, 65);
        sec_hash_48(session_key, temp_hash, server_key, client_key, 65);

        /* Store first 16 bytes of session key, for generating signatures */
        memcpy(licence_sign_key, session_key, 16);

        /* Generate RC4 key */
        sec_hash_16(licence_key, &session_key[16], client_key, server_key);
}

static void
licence_generate_hwid(uint8 * hwid)
{
        buf_out_uint32(hwid, 2);
        strncpy((char *) (hwid + 4), hostname, LICENCE_HWID_SIZE - 4);
}

#ifdef SAVE_LICENCE
/* Present an existing licence to the server */
static void
licence_present(uint8 * client_random, uint8 * rsa_data,
                uint8 * licence_data, int licence_size, uint8 * hwid, uint8 * signature)
{
        uint32 sec_flags = SEC_LICENCE_NEG;
        uint16 length =
                16 + SEC_RANDOM_SIZE + SEC_MODULUS_SIZE + SEC_PADDING_SIZE +
                licence_size + LICENCE_HWID_SIZE + LICENCE_SIGNATURE_SIZE;
        STREAM s;

        s = sec_init(sec_flags, length + 4);

        out_uint16_le(s, LICENCE_TAG_PRESENT);
        out_uint16_le(s, length);

        out_uint32_le(s, 1);
        out_uint16(s, 0);
        out_uint16_le(s, 0x0201);

        out_uint8p(s, client_random, SEC_RANDOM_SIZE);
        out_uint16(s, 0);
        out_uint16_le(s, (SEC_MODULUS_SIZE + SEC_PADDING_SIZE));
        out_uint8p(s, rsa_data, SEC_MODULUS_SIZE);
        out_uint8s(s, SEC_PADDING_SIZE);

        out_uint16_le(s, 1);
        out_uint16_le(s, licence_size);
        out_uint8p(s, licence_data, licence_size);

        out_uint16_le(s, 1);
        out_uint16_le(s, LICENCE_HWID_SIZE);
        out_uint8p(s, hwid, LICENCE_HWID_SIZE);

        out_uint8p(s, signature, LICENCE_SIGNATURE_SIZE);

        s_mark_end(s);
        sec_send(s, sec_flags);
}
#endif

/* Send a licence request packet */
static void
licence_send_request(uint8 * client_random, uint8 * rsa_data, char *user, char *host)
{
        uint32 sec_flags = SEC_LICENCE_NEG;
        uint16 userlen = strlen(user) + 1;
        uint16 hostlen = strlen(host) + 1;
        uint16 length = 128 + userlen + hostlen;
        STREAM s;

        s = sec_init(sec_flags, length + 2);

        out_uint16_le(s, LICENCE_TAG_REQUEST);
        out_uint16_le(s, length);

        out_uint32_le(s, 1);
        out_uint16(s, 0);
        out_uint16_le(s, 0xff01);

        out_uint8p(s, client_random, SEC_RANDOM_SIZE);
        out_uint16(s, 0);
        out_uint16_le(s, (SEC_MODULUS_SIZE + SEC_PADDING_SIZE));
        out_uint8p(s, rsa_data, SEC_MODULUS_SIZE);
        out_uint8s(s, SEC_PADDING_SIZE);

        out_uint16(s, LICENCE_TAG_USER);
        out_uint16(s, userlen);
        out_uint8p(s, user, userlen);

        out_uint16(s, LICENCE_TAG_HOST);
        out_uint16(s, hostlen);
        out_uint8p(s, host, hostlen);

        s_mark_end(s);
        sec_send(s, sec_flags);
}

/* Process a licence demand packet */
static void
licence_process_demand(STREAM s)
{
        uint8 null_data[SEC_MODULUS_SIZE];
        uint8 *server_random;
#ifdef SAVE_LICENCE
        uint8 signature[LICENCE_SIGNATURE_SIZE];
        uint8 hwid[LICENCE_HWID_SIZE];
        uint8 *licence_data;
        int licence_size;
        RC4_KEY crypt_key;
#endif

        /* Retrieve the server random from the incoming packet */
        in_uint8p(s, server_random, SEC_RANDOM_SIZE);

        /* We currently use null client keys. This is a bit naughty but, hey,
           the security of licence negotiation isn't exactly paramount. */
        memset(null_data, 0, sizeof(null_data));
        licence_generate_keys(null_data, server_random, null_data);

#ifdef SAVE_LICENCE
        licence_size = load_licence(&licence_data);
        if (licence_size != -1)
        {
                /* Generate a signature for the HWID buffer */
                licence_generate_hwid(hwid);
                sec_sign(signature, 16, licence_sign_key, 16, hwid, sizeof(hwid));

                /* Now encrypt the HWID */
                RC4_set_key(&crypt_key, 16, licence_key);
                RC4(&crypt_key, sizeof(hwid), hwid, hwid);

                licence_present(null_data, null_data, licence_data, licence_size, hwid, signature);
                xfree(licence_data);
                return;
        }
#endif

        licence_send_request(null_data, null_data, username, hostname);
}

/* Send an authentication response packet */
static void
licence_send_authresp(uint8 * token, uint8 * crypt_hwid, uint8 * signature)
{
        uint32 sec_flags = SEC_LICENCE_NEG;
        uint16 length = 58;
        STREAM s;

        s = sec_init(sec_flags, length + 2);

        out_uint16_le(s, LICENCE_TAG_AUTHRESP);
        out_uint16_le(s, length);

        out_uint16_le(s, 1);
        out_uint16_le(s, LICENCE_TOKEN_SIZE);
        out_uint8p(s, token, LICENCE_TOKEN_SIZE);

        out_uint16_le(s, 1);
        out_uint16_le(s, LICENCE_HWID_SIZE);
        out_uint8p(s, crypt_hwid, LICENCE_HWID_SIZE);

        out_uint8p(s, signature, LICENCE_SIGNATURE_SIZE);

        s_mark_end(s);
        sec_send(s, sec_flags);
}

/* Parse an authentication request packet */
static BOOL
licence_parse_authreq(STREAM s, uint8 ** token, uint8 ** signature)
{
        uint16 tokenlen;

        in_uint8s(s, 6);        /* unknown: f8 3d 15 00 04 f6 */

        in_uint16_le(s, tokenlen);
        if (tokenlen != LICENCE_TOKEN_SIZE)
        {
                error("token len %d\n", tokenlen);
                return False;
        }

        in_uint8p(s, *token, tokenlen);
        in_uint8p(s, *signature, LICENCE_SIGNATURE_SIZE);

        return s_check_end(s);
}

/* Process an authentication request packet */
static void
licence_process_authreq(STREAM s)
{
        uint8 *in_token, *in_sig;
        uint8 out_token[LICENCE_TOKEN_SIZE], decrypt_token[LICENCE_TOKEN_SIZE];
        uint8 hwid[LICENCE_HWID_SIZE], crypt_hwid[LICENCE_HWID_SIZE];
        uint8 sealed_buffer[LICENCE_TOKEN_SIZE + LICENCE_HWID_SIZE];
        uint8 out_sig[LICENCE_SIGNATURE_SIZE];
        RC4_KEY crypt_key;

        /* Parse incoming packet and save the encrypted token */
        licence_parse_authreq(s, &in_token, &in_sig);
        memcpy(out_token, in_token, LICENCE_TOKEN_SIZE);

        /* Decrypt the token. It should read TEST in Unicode. */
        RC4_set_key(&crypt_key, 16, licence_key);
        RC4(&crypt_key, LICENCE_TOKEN_SIZE, in_token, decrypt_token);

        /* Generate a signature for a buffer of token and HWID */
        licence_generate_hwid(hwid);
        memcpy(sealed_buffer, decrypt_token, LICENCE_TOKEN_SIZE);
        memcpy(sealed_buffer + LICENCE_TOKEN_SIZE, hwid, LICENCE_HWID_SIZE);
        sec_sign(out_sig, 16, licence_sign_key, 16, sealed_buffer, sizeof(sealed_buffer));

        /* Now encrypt the HWID */
        RC4_set_key(&crypt_key, 16, licence_key);
        RC4(&crypt_key, LICENCE_HWID_SIZE, hwid, crypt_hwid);

        licence_send_authresp(out_token, crypt_hwid, out_sig);
}

/* Process an licence issue packet */
static void
licence_process_issue(STREAM s)
{
        RC4_KEY crypt_key;
        uint32 length;
        uint16 check;

        in_uint8s(s, 2);        /* 3d 45 - unknown */
        in_uint16_le(s, length);
        if (!s_check_rem(s, length))
                return;

        RC4_set_key(&crypt_key, 16, licence_key);
        RC4(&crypt_key, length, s->p, s->p);

        in_uint16(s, check);
        if (check != 0)
                return;

        licence_issued = True;

#ifdef SAVE_LICENCE
        save_licence(s->p, length - 2);
#endif
}

/* Process a licence packet */
void
licence_process(STREAM s)
{
        uint16 tag;

        in_uint16_le(s, tag);
        in_uint8s(s, 2);        /* length */

        switch (tag)
        {
                case LICENCE_TAG_DEMAND:
                        licence_process_demand(s);
                        break;

                case LICENCE_TAG_AUTHREQ:
                        licence_process_authreq(s);
                        break;

                case LICENCE_TAG_ISSUE:
                        licence_process_issue(s);
                        break;

                case LICENCE_TAG_REISSUE:
                        break;

                case LICENCE_TAG_RESULT:
                        break;

                default:
                        unimpl("licence tag 0x%x\n", tag);
        }
}
1	matty	10	/*
2			rdesktop: A Remote Desktop Protocol client.
3			RDP licensing negotiation
4	matthewc	207	Copyright (C) Matthew Chapman 1999-2002
5	matty	10
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	jsorg71	60
11	matty	10	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			#include "rdesktop.h"
22	astrand	293
23			#ifdef WITH_OPENSSL
24			#include <openssl/rc4.h>
25			#else
26	matty	10	#include "crypto/rc4.h"
27	astrand	293	#endif
28	matty	10
29			extern char username[16];
30			extern char hostname[16];
31
32			static uint8 licence_key[16];
33			static uint8 licence_sign_key[16];
34
35	matty	28	BOOL licence_issued = False;
36
37	matty	10	/* Generate a session key and RC4 keys, given client and server randoms */
38	matthewc	39	static void
39	astrand	82	licence_generate_keys(uint8 * client_key, uint8 * server_key, uint8 * client_rsa)
40	matty	10	{
41			uint8 session_key[48];
42			uint8 temp_hash[48];
43
44			/* Generate session key - two rounds of sec_hash_48 */
45	matty	24	sec_hash_48(temp_hash, client_rsa, client_key, server_key, 65);
46			sec_hash_48(session_key, temp_hash, server_key, client_key, 65);
47	matty	10
48			/* Store first 16 bytes of session key, for generating signatures */
49	matty	24	memcpy(licence_sign_key, session_key, 16);
50	matty	10
51			/* Generate RC4 key */
52			sec_hash_16(licence_key, &session_key[16], client_key, server_key);
53			}
54
55	matthewc	39	static void
56	astrand	64	licence_generate_hwid(uint8 * hwid)
57	matthewc	39	{
58			buf_out_uint32(hwid, 2);
59	astrand	77	strncpy((char *) (hwid + 4), hostname, LICENCE_HWID_SIZE - 4);
60	matthewc	39	}
61
62	matthewc	159	#ifdef SAVE_LICENCE
63	matthewc	39	/* Present an existing licence to the server */
64			static void
65	astrand	64	licence_present(uint8 * client_random, uint8 * rsa_data,
66	astrand	82	uint8 * licence_data, int licence_size, uint8 * hwid, uint8 * signature)
67	matthewc	39	{
68			uint32 sec_flags = SEC_LICENCE_NEG;
69	astrand	64	uint16 length =
70			16 + SEC_RANDOM_SIZE + SEC_MODULUS_SIZE + SEC_PADDING_SIZE +
71			licence_size + LICENCE_HWID_SIZE + LICENCE_SIGNATURE_SIZE;
72	matthewc	39	STREAM s;
73
74			s = sec_init(sec_flags, length + 4);
75
76			out_uint16_le(s, LICENCE_TAG_PRESENT);
77			out_uint16_le(s, length);
78
79			out_uint32_le(s, 1);
80			out_uint16(s, 0);
81			out_uint16_le(s, 0x0201);
82
83			out_uint8p(s, client_random, SEC_RANDOM_SIZE);
84			out_uint16(s, 0);
85			out_uint16_le(s, (SEC_MODULUS_SIZE + SEC_PADDING_SIZE));
86			out_uint8p(s, rsa_data, SEC_MODULUS_SIZE);
87			out_uint8s(s, SEC_PADDING_SIZE);
88
89			out_uint16_le(s, 1);
90			out_uint16_le(s, licence_size);
91			out_uint8p(s, licence_data, licence_size);
92
93			out_uint16_le(s, 1);
94			out_uint16_le(s, LICENCE_HWID_SIZE);
95			out_uint8p(s, hwid, LICENCE_HWID_SIZE);
96
97			out_uint8p(s, signature, LICENCE_SIGNATURE_SIZE);
98
99			s_mark_end(s);
100			sec_send(s, sec_flags);
101			}
102	matthewc	159	#endif
103	matthewc	39
104	matty	10	/* Send a licence request packet */
105	matty	25	static void
106	astrand	82	licence_send_request(uint8 * client_random, uint8 * rsa_data, char user, char host)
107	matty	10	{
108			uint32 sec_flags = SEC_LICENCE_NEG;
109			uint16 userlen = strlen(user) + 1;
110			uint16 hostlen = strlen(host) + 1;
111	jsorg71	60	uint16 length = 128 + userlen + hostlen;
112	matty	10	STREAM s;
113
114			s = sec_init(sec_flags, length + 2);
115
116			out_uint16_le(s, LICENCE_TAG_REQUEST);
117			out_uint16_le(s, length);
118
119			out_uint32_le(s, 1);
120	matthewc	39	out_uint16(s, 0);
121			out_uint16_le(s, 0xff01);
122	matty	10
123			out_uint8p(s, client_random, SEC_RANDOM_SIZE);
124			out_uint16(s, 0);
125			out_uint16_le(s, (SEC_MODULUS_SIZE + SEC_PADDING_SIZE));
126			out_uint8p(s, rsa_data, SEC_MODULUS_SIZE);
127			out_uint8s(s, SEC_PADDING_SIZE);
128
129			out_uint16(s, LICENCE_TAG_USER);
130			out_uint16(s, userlen);
131			out_uint8p(s, user, userlen);
132
133			out_uint16(s, LICENCE_TAG_HOST);
134			out_uint16(s, hostlen);
135			out_uint8p(s, host, hostlen);
136
137			s_mark_end(s);
138			sec_send(s, sec_flags);
139			}
140
141			/* Process a licence demand packet */
142	matty	25	static void
143			licence_process_demand(STREAM s)
144	matty	10	{
145			uint8 null_data[SEC_MODULUS_SIZE];
146	matthewc	190	uint8 *server_random;
147			#ifdef SAVE_LICENCE
148			uint8 signature[LICENCE_SIGNATURE_SIZE];
149	matthewc	39	uint8 hwid[LICENCE_HWID_SIZE];
150			uint8 *licence_data;
151			int licence_size;
152			RC4_KEY crypt_key;
153	matthewc	190	#endif
154	matty	10
155			/* Retrieve the server random from the incoming packet */
156			in_uint8p(s, server_random, SEC_RANDOM_SIZE);
157
158			/* We currently use null client keys. This is a bit naughty but, hey,
159			the security of licence negotiation isn't exactly paramount. */
160			memset(null_data, 0, sizeof(null_data));
161			licence_generate_keys(null_data, server_random, null_data);
162
163	matthewc	159	#ifdef SAVE_LICENCE
164	matthewc	39	licence_size = load_licence(&licence_data);
165	matthewc	159	if (licence_size != -1)
166	matthewc	39	{
167	matthewc	159	/* Generate a signature for the HWID buffer */
168			licence_generate_hwid(hwid);
169			sec_sign(signature, 16, licence_sign_key, 16, hwid, sizeof(hwid));
170
171			/* Now encrypt the HWID */
172			RC4_set_key(&crypt_key, 16, licence_key);
173			RC4(&crypt_key, sizeof(hwid), hwid, hwid);
174
175			licence_present(null_data, null_data, licence_data, licence_size, hwid, signature);
176			xfree(licence_data);
177	matthewc	39	return;
178			}
179	matthewc	159	#endif
180	matthewc	39
181	matthewc	159	licence_send_request(null_data, null_data, username, hostname);
182	matty	10	}
183
184			/* Send an authentication response packet */
185	matty	25	static void
186	astrand	64	licence_send_authresp(uint8 * token, uint8 * crypt_hwid, uint8 * signature)
187	matty	10	{
188			uint32 sec_flags = SEC_LICENCE_NEG;
189			uint16 length = 58;
190			STREAM s;
191
192			s = sec_init(sec_flags, length + 2);
193
194			out_uint16_le(s, LICENCE_TAG_AUTHRESP);
195			out_uint16_le(s, length);
196
197			out_uint16_le(s, 1);
198			out_uint16_le(s, LICENCE_TOKEN_SIZE);
199			out_uint8p(s, token, LICENCE_TOKEN_SIZE);
200
201			out_uint16_le(s, 1);
202			out_uint16_le(s, LICENCE_HWID_SIZE);
203			out_uint8p(s, crypt_hwid, LICENCE_HWID_SIZE);
204
205			out_uint8p(s, signature, LICENCE_SIGNATURE_SIZE);
206
207			s_mark_end(s);
208			sec_send(s, sec_flags);
209			}
210
211			/* Parse an authentication request packet */
212	matty	25	static BOOL
213	astrand	64	licence_parse_authreq(STREAM s, uint8 token, uint8 signature)
214	matty	10	{
215			uint16 tokenlen;
216
217	matty	24	in_uint8s(s, 6); /* unknown: f8 3d 15 00 04 f6 */
218	matty	10
219			in_uint16_le(s, tokenlen);
220			if (tokenlen != LICENCE_TOKEN_SIZE)
221			{
222	matty	30	error("token len %d\n", tokenlen);
223	matty	10	return False;
224			}
225
226			in_uint8p(s, *token, tokenlen);
227			in_uint8p(s, *signature, LICENCE_SIGNATURE_SIZE);
228
229			return s_check_end(s);
230			}
231
232			/* Process an authentication request packet */
233	matty	25	static void
234			licence_process_authreq(STREAM s)
235	matty	10	{
236			uint8 in_token, in_sig;
237	astrand	82	uint8 out_token[LICENCE_TOKEN_SIZE], decrypt_token[LICENCE_TOKEN_SIZE];
238	matty	10	uint8 hwid[LICENCE_HWID_SIZE], crypt_hwid[LICENCE_HWID_SIZE];
239			uint8 sealed_buffer[LICENCE_TOKEN_SIZE + LICENCE_HWID_SIZE];
240			uint8 out_sig[LICENCE_SIGNATURE_SIZE];
241			RC4_KEY crypt_key;
242
243			/* Parse incoming packet and save the encrypted token */
244			licence_parse_authreq(s, &in_token, &in_sig);
245			memcpy(out_token, in_token, LICENCE_TOKEN_SIZE);
246
247			/* Decrypt the token. It should read TEST in Unicode. */
248			RC4_set_key(&crypt_key, 16, licence_key);
249			RC4(&crypt_key, LICENCE_TOKEN_SIZE, in_token, decrypt_token);
250
251			/* Generate a signature for a buffer of token and HWID */
252	matthewc	39	licence_generate_hwid(hwid);
253	matty	10	memcpy(sealed_buffer, decrypt_token, LICENCE_TOKEN_SIZE);
254			memcpy(sealed_buffer + LICENCE_TOKEN_SIZE, hwid, LICENCE_HWID_SIZE);
255	astrand	82	sec_sign(out_sig, 16, licence_sign_key, 16, sealed_buffer, sizeof(sealed_buffer));
256	matty	10
257			/* Now encrypt the HWID */
258			RC4_set_key(&crypt_key, 16, licence_key);
259			RC4(&crypt_key, LICENCE_HWID_SIZE, hwid, crypt_hwid);
260
261			licence_send_authresp(out_token, crypt_hwid, out_sig);
262			}
263
264			/* Process an licence issue packet */
265	matty	25	static void
266			licence_process_issue(STREAM s)
267	matty	10	{
268			RC4_KEY crypt_key;
269			uint32 length;
270			uint16 check;
271
272	matty	24	in_uint8s(s, 2); /* 3d 45 - unknown */
273	matty	10	in_uint16_le(s, length);
274			if (!s_check_rem(s, length))
275			return;
276
277			RC4_set_key(&crypt_key, 16, licence_key);
278			RC4(&crypt_key, length, s->p, s->p);
279
280			in_uint16(s, check);
281			if (check != 0)
282			return;
283
284	matty	28	licence_issued = True;
285	matthewc	159
286			#ifdef SAVE_LICENCE
287	astrand	64	save_licence(s->p, length - 2);
288	matthewc	159	#endif
289	matty	10	}
290
291			/* Process a licence packet */
292	matty	25	void
293			licence_process(STREAM s)
294	matty	10	{
295			uint16 tag;
296
297			in_uint16_le(s, tag);
298	matty	24	in_uint8s(s, 2); /* length */
299	matty	10
300			switch (tag)
301			{
302			case LICENCE_TAG_DEMAND:
303			licence_process_demand(s);
304			break;
305
306			case LICENCE_TAG_AUTHREQ:
307			licence_process_authreq(s);
308			break;
309
310			case LICENCE_TAG_ISSUE:
311			licence_process_issue(s);
312			break;
313
314	matthewc	39	case LICENCE_TAG_REISSUE:
315			break;
316
317	matty	10	case LICENCE_TAG_RESULT:
318			break;
319
320			default:
321	matty	30	unimpl("licence tag 0x%x\n", tag);
322	matty	10	}
323			}