trunk/rdesktop/licence.c

/*
   rdesktop: A Remote Desktop Protocol client.
   RDP licensing negotiation
   Copyright (C) Matthew Chapman 1999-2001
   
   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"
#include "crypto/rc4.h"

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

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(hwid + 4, hostname, LICENCE_HWID_SIZE - 4);
}

/* 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);
}

/* 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 = 120 + 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 hwid[LICENCE_HWID_SIZE];
        uint8 signature[LICENCE_SIGNATURE_SIZE];
        uint8 *server_random;
        uint8 *licence_data;
        int licence_size;
        RC4_KEY crypt_key;

        /* 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);

        licence_size = load_licence(&licence_data);
        if (licence_size == -1)
        {
                licence_send_request(null_data, null_data, username, hostname);
                return;
        }

        /* Generate a signature for the HWID buffer */
        licence_generate_hwid(hwid);
        sec_sign(signature, 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);
}

/* 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, licence_sign_key, 16,
                 sealed_buffer, sizeof(sealed_buffer));

        /* Deliberately break signature if licencing disabled */
        if (!licence)
                memset(out_sig, 0, sizeof(out_sig));

        /* 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;
        save_licence(s->p, length-2);
}

/* 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	matty	30	Copyright (C) Matthew Chapman 1999-2001
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
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			#include "rdesktop.h"
22			#include "crypto/rc4.h"
23
24			extern char username[16];
25			extern char hostname[16];
26			extern BOOL licence;
27
28			static uint8 licence_key[16];
29			static uint8 licence_sign_key[16];
30
31	matty	28	BOOL licence_issued = False;
32
33	matty	10	/* Generate a session key and RC4 keys, given client and server randoms */
34	matthewc	39	static void
35	matty	25	licence_generate_keys(uint8 client_key, uint8 server_key, uint8 *client_rsa)
36	matty	10	{
37			uint8 session_key[48];
38			uint8 temp_hash[48];
39
40			/* Generate session key - two rounds of sec_hash_48 */
41	matty	24	sec_hash_48(temp_hash, client_rsa, client_key, server_key, 65);
42			sec_hash_48(session_key, temp_hash, server_key, client_key, 65);
43	matty	10
44			/* Store first 16 bytes of session key, for generating signatures */
45	matty	24	memcpy(licence_sign_key, session_key, 16);
46	matty	10
47			/* Generate RC4 key */
48			sec_hash_16(licence_key, &session_key[16], client_key, server_key);
49			}
50
51	matthewc	39	static void
52			licence_generate_hwid(uint8 *hwid)
53			{
54			buf_out_uint32(hwid, 2);
55			strncpy(hwid + 4, hostname, LICENCE_HWID_SIZE - 4);
56			}
57
58			/* Present an existing licence to the server */
59			static void
60			licence_present(uint8 client_random, uint8 rsa_data,
61			uint8 *licence_data, int licence_size,
62			uint8 hwid, uint8 signature)
63			{
64			uint32 sec_flags = SEC_LICENCE_NEG;
65			uint16 length = 16 + SEC_RANDOM_SIZE + SEC_MODULUS_SIZE + SEC_PADDING_SIZE
66			+ licence_size + LICENCE_HWID_SIZE + LICENCE_SIGNATURE_SIZE;
67			STREAM s;
68
69			s = sec_init(sec_flags, length + 4);
70
71			out_uint16_le(s, LICENCE_TAG_PRESENT);
72			out_uint16_le(s, length);
73
74			out_uint32_le(s, 1);
75			out_uint16(s, 0);
76			out_uint16_le(s, 0x0201);
77
78			out_uint8p(s, client_random, SEC_RANDOM_SIZE);
79			out_uint16(s, 0);
80			out_uint16_le(s, (SEC_MODULUS_SIZE + SEC_PADDING_SIZE));
81			out_uint8p(s, rsa_data, SEC_MODULUS_SIZE);
82			out_uint8s(s, SEC_PADDING_SIZE);
83
84			out_uint16_le(s, 1);
85			out_uint16_le(s, licence_size);
86			out_uint8p(s, licence_data, licence_size);
87
88			out_uint16_le(s, 1);
89			out_uint16_le(s, LICENCE_HWID_SIZE);
90			out_uint8p(s, hwid, LICENCE_HWID_SIZE);
91
92			out_uint8p(s, signature, LICENCE_SIGNATURE_SIZE);
93
94			s_mark_end(s);
95			sec_send(s, sec_flags);
96			}
97
98	matty	10	/* Send a licence request packet */
99	matty	25	static void
100			licence_send_request(uint8 client_random, uint8 rsa_data,
101			char user, char host)
102	matty	10	{
103			uint32 sec_flags = SEC_LICENCE_NEG;
104			uint16 userlen = strlen(user) + 1;
105			uint16 hostlen = strlen(host) + 1;
106			uint16 length = 120 + userlen + hostlen;
107			STREAM s;
108
109			s = sec_init(sec_flags, length + 2);
110
111			out_uint16_le(s, LICENCE_TAG_REQUEST);
112			out_uint16_le(s, length);
113
114			out_uint32_le(s, 1);
115	matthewc	39	out_uint16(s, 0);
116			out_uint16_le(s, 0xff01);
117	matty	10
118			out_uint8p(s, client_random, SEC_RANDOM_SIZE);
119			out_uint16(s, 0);
120			out_uint16_le(s, (SEC_MODULUS_SIZE + SEC_PADDING_SIZE));
121			out_uint8p(s, rsa_data, SEC_MODULUS_SIZE);
122			out_uint8s(s, SEC_PADDING_SIZE);
123
124			out_uint16(s, LICENCE_TAG_USER);
125			out_uint16(s, userlen);
126			out_uint8p(s, user, userlen);
127
128			out_uint16(s, LICENCE_TAG_HOST);
129			out_uint16(s, hostlen);
130			out_uint8p(s, host, hostlen);
131
132			s_mark_end(s);
133			sec_send(s, sec_flags);
134			}
135
136			/* Process a licence demand packet */
137	matty	25	static void
138			licence_process_demand(STREAM s)
139	matty	10	{
140			uint8 null_data[SEC_MODULUS_SIZE];
141	matthewc	39	uint8 hwid[LICENCE_HWID_SIZE];
142			uint8 signature[LICENCE_SIGNATURE_SIZE];
143	matty	10	uint8 *server_random;
144	matthewc	39	uint8 *licence_data;
145			int licence_size;
146			RC4_KEY crypt_key;
147	matty	10
148			/* Retrieve the server random from the incoming packet */
149			in_uint8p(s, server_random, SEC_RANDOM_SIZE);
150
151			/* We currently use null client keys. This is a bit naughty but, hey,
152			the security of licence negotiation isn't exactly paramount. */
153			memset(null_data, 0, sizeof(null_data));
154			licence_generate_keys(null_data, server_random, null_data);
155
156	matthewc	39	licence_size = load_licence(&licence_data);
157			if (licence_size == -1)
158			{
159			licence_send_request(null_data, null_data, username, hostname);
160			return;
161			}
162
163			/* Generate a signature for the HWID buffer */
164			licence_generate_hwid(hwid);
165			sec_sign(signature, licence_sign_key, 16, hwid, sizeof(hwid));
166
167			/* Now encrypt the HWID */
168			RC4_set_key(&crypt_key, 16, licence_key);
169			RC4(&crypt_key, sizeof(hwid), hwid, hwid);
170
171			licence_present(null_data, null_data, licence_data, licence_size,
172			hwid, signature);
173			xfree(licence_data);
174	matty	10	}
175
176			/* Send an authentication response packet */
177	matty	25	static void
178			licence_send_authresp(uint8 token, uint8 crypt_hwid, uint8 *signature)
179	matty	10	{
180			uint32 sec_flags = SEC_LICENCE_NEG;
181			uint16 length = 58;
182			STREAM s;
183
184			s = sec_init(sec_flags, length + 2);
185
186			out_uint16_le(s, LICENCE_TAG_AUTHRESP);
187			out_uint16_le(s, length);
188
189			out_uint16_le(s, 1);
190			out_uint16_le(s, LICENCE_TOKEN_SIZE);
191			out_uint8p(s, token, LICENCE_TOKEN_SIZE);
192
193			out_uint16_le(s, 1);
194			out_uint16_le(s, LICENCE_HWID_SIZE);
195			out_uint8p(s, crypt_hwid, LICENCE_HWID_SIZE);
196
197			out_uint8p(s, signature, LICENCE_SIGNATURE_SIZE);
198
199			s_mark_end(s);
200			sec_send(s, sec_flags);
201			}
202
203			/* Parse an authentication request packet */
204	matty	25	static BOOL
205			licence_parse_authreq(STREAM s, uint8 token, uint8 signature)
206	matty	10	{
207			uint16 tokenlen;
208
209	matty	24	in_uint8s(s, 6); /* unknown: f8 3d 15 00 04 f6 */
210	matty	10
211			in_uint16_le(s, tokenlen);
212			if (tokenlen != LICENCE_TOKEN_SIZE)
213			{
214	matty	30	error("token len %d\n", tokenlen);
215	matty	10	return False;
216			}
217
218			in_uint8p(s, *token, tokenlen);
219			in_uint8p(s, *signature, LICENCE_SIGNATURE_SIZE);
220
221			return s_check_end(s);
222			}
223
224			/* Process an authentication request packet */
225	matty	25	static void
226			licence_process_authreq(STREAM s)
227	matty	10	{
228			uint8 in_token, in_sig;
229	matty	24	uint8 out_token[LICENCE_TOKEN_SIZE],
230			decrypt_token[LICENCE_TOKEN_SIZE];
231	matty	10	uint8 hwid[LICENCE_HWID_SIZE], crypt_hwid[LICENCE_HWID_SIZE];
232			uint8 sealed_buffer[LICENCE_TOKEN_SIZE + LICENCE_HWID_SIZE];
233			uint8 out_sig[LICENCE_SIGNATURE_SIZE];
234			RC4_KEY crypt_key;
235
236			/* Parse incoming packet and save the encrypted token */
237			licence_parse_authreq(s, &in_token, &in_sig);
238			memcpy(out_token, in_token, LICENCE_TOKEN_SIZE);
239
240			/* Decrypt the token. It should read TEST in Unicode. */
241			RC4_set_key(&crypt_key, 16, licence_key);
242			RC4(&crypt_key, LICENCE_TOKEN_SIZE, in_token, decrypt_token);
243
244			/* Generate a signature for a buffer of token and HWID */
245	matthewc	39	licence_generate_hwid(hwid);
246	matty	10	memcpy(sealed_buffer, decrypt_token, LICENCE_TOKEN_SIZE);
247			memcpy(sealed_buffer + LICENCE_TOKEN_SIZE, hwid, LICENCE_HWID_SIZE);
248			sec_sign(out_sig, licence_sign_key, 16,
249	matty	24	sealed_buffer, sizeof(sealed_buffer));
250	matty	10
251			/* Deliberately break signature if licencing disabled */
252			if (!licence)
253			memset(out_sig, 0, sizeof(out_sig));
254
255			/* Now encrypt the HWID */
256			RC4_set_key(&crypt_key, 16, licence_key);
257			RC4(&crypt_key, LICENCE_HWID_SIZE, hwid, crypt_hwid);
258
259			licence_send_authresp(out_token, crypt_hwid, out_sig);
260			}
261
262			/* Process an licence issue packet */
263	matty	25	static void
264			licence_process_issue(STREAM s)
265	matty	10	{
266			RC4_KEY crypt_key;
267			uint32 length;
268			uint16 check;
269
270	matty	24	in_uint8s(s, 2); /* 3d 45 - unknown */
271	matty	10	in_uint16_le(s, length);
272			if (!s_check_rem(s, length))
273			return;
274
275			RC4_set_key(&crypt_key, 16, licence_key);
276			RC4(&crypt_key, length, s->p, s->p);
277
278			in_uint16(s, check);
279			if (check != 0)
280			return;
281
282	matty	28	licence_issued = True;
283	matthewc	39	save_licence(s->p, length-2);
284	matty	10	}
285
286			/* Process a licence packet */
287	matty	25	void
288			licence_process(STREAM s)
289	matty	10	{
290			uint16 tag;
291
292			in_uint16_le(s, tag);
293	matty	24	in_uint8s(s, 2); /* length */
294	matty	10
295			switch (tag)
296			{
297			case LICENCE_TAG_DEMAND:
298			licence_process_demand(s);
299			break;
300
301			case LICENCE_TAG_AUTHREQ:
302			licence_process_authreq(s);
303			break;
304
305			case LICENCE_TAG_ISSUE:
306			licence_process_issue(s);
307			break;
308
309	matthewc	39	case LICENCE_TAG_REISSUE:
310			break;
311
312	matty	10	case LICENCE_TAG_RESULT:
313			break;
314
315			default:
316	matty	30	unimpl("licence tag 0x%x\n", tag);
317	matty	10	}
318			}