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((char *) (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 = 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 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, 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);
}

/* 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));

        /* 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	/*
2	rdesktop: A Remote Desktop Protocol client.
3	RDP licensing negotiation
4	Copyright (C) Matthew Chapman 1999-2001
5
6	This program is free software; you can redistribute it and/or modify
7	it under the terms of the GNU General Public License as published by
8	the Free Software Foundation; either version 2 of the License, or
9	(at your option) any later version.
10
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	BOOL licence_issued = False;
32
33	/* Generate a session key and RC4 keys, given client and server randoms */
34	static void
35	licence_generate_keys(uint8 * client_key, uint8 * server_key, uint8 * client_rsa)
36	{
37	uint8 session_key[48];
38	uint8 temp_hash[48];
39
40	/* Generate session key - two rounds of sec_hash_48 */
41	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
44	/* Store first 16 bytes of session key, for generating signatures */
45	memcpy(licence_sign_key, session_key, 16);
46
47	/* Generate RC4 key */
48	sec_hash_16(licence_key, &session_key[16], client_key, server_key);
49	}
50
51	static void
52	licence_generate_hwid(uint8 * hwid)
53	{
54	buf_out_uint32(hwid, 2);
55	strncpy((char *) (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, uint8 * hwid, uint8 * signature)
62	{
63	uint32 sec_flags = SEC_LICENCE_NEG;
64	uint16 length =
65	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	/* Send a licence request packet */
99	static void
100	licence_send_request(uint8 * client_random, uint8 * rsa_data, char user, char host)
101	{
102	uint32 sec_flags = SEC_LICENCE_NEG;
103	uint16 userlen = strlen(user) + 1;
104	uint16 hostlen = strlen(host) + 1;
105	uint16 length = 128 + userlen + hostlen;
106	STREAM s;
107
108	s = sec_init(sec_flags, length + 2);
109
110	out_uint16_le(s, LICENCE_TAG_REQUEST);
111	out_uint16_le(s, length);
112
113	out_uint32_le(s, 1);
114	out_uint16(s, 0);
115	out_uint16_le(s, 0xff01);
116
117	out_uint8p(s, client_random, SEC_RANDOM_SIZE);
118	out_uint16(s, 0);
119	out_uint16_le(s, (SEC_MODULUS_SIZE + SEC_PADDING_SIZE));
120	out_uint8p(s, rsa_data, SEC_MODULUS_SIZE);
121	out_uint8s(s, SEC_PADDING_SIZE);
122
123	out_uint16(s, LICENCE_TAG_USER);
124	out_uint16(s, userlen);
125	out_uint8p(s, user, userlen);
126
127	out_uint16(s, LICENCE_TAG_HOST);
128	out_uint16(s, hostlen);
129	out_uint8p(s, host, hostlen);
130
131	s_mark_end(s);
132	sec_send(s, sec_flags);
133	}
134
135	/* Process a licence demand packet */
136	static void
137	licence_process_demand(STREAM s)
138	{
139	uint8 null_data[SEC_MODULUS_SIZE];
140	uint8 hwid[LICENCE_HWID_SIZE];
141	uint8 signature[LICENCE_SIGNATURE_SIZE];
142	uint8 *server_random;
143	uint8 *licence_data;
144	int licence_size;
145	RC4_KEY crypt_key;
146
147	/* Retrieve the server random from the incoming packet */
148	in_uint8p(s, server_random, SEC_RANDOM_SIZE);
149
150	/* We currently use null client keys. This is a bit naughty but, hey,
151	the security of licence negotiation isn't exactly paramount. */
152	memset(null_data, 0, sizeof(null_data));
153	licence_generate_keys(null_data, server_random, null_data);
154
155	licence_size = load_licence(&licence_data);
156	if (licence_size == -1)
157	{
158	licence_send_request(null_data, null_data, username, hostname);
159	return;
160	}
161
162	/* Generate a signature for the HWID buffer */
163	licence_generate_hwid(hwid);
164	sec_sign(signature, 16, licence_sign_key, 16, hwid, sizeof(hwid));
165
166	/* Now encrypt the HWID */
167	RC4_set_key(&crypt_key, 16, licence_key);
168	RC4(&crypt_key, sizeof(hwid), hwid, hwid);
169
170	licence_present(null_data, null_data, licence_data, licence_size, hwid, signature);
171	xfree(licence_data);
172	}
173
174	/* Send an authentication response packet */
175	static void
176	licence_send_authresp(uint8 * token, uint8 * crypt_hwid, uint8 * signature)
177	{
178	uint32 sec_flags = SEC_LICENCE_NEG;
179	uint16 length = 58;
180	STREAM s;
181
182	s = sec_init(sec_flags, length + 2);
183
184	out_uint16_le(s, LICENCE_TAG_AUTHRESP);
185	out_uint16_le(s, length);
186
187	out_uint16_le(s, 1);
188	out_uint16_le(s, LICENCE_TOKEN_SIZE);
189	out_uint8p(s, token, LICENCE_TOKEN_SIZE);
190
191	out_uint16_le(s, 1);
192	out_uint16_le(s, LICENCE_HWID_SIZE);
193	out_uint8p(s, crypt_hwid, LICENCE_HWID_SIZE);
194
195	out_uint8p(s, signature, LICENCE_SIGNATURE_SIZE);
196
197	s_mark_end(s);
198	sec_send(s, sec_flags);
199	}
200
201	/* Parse an authentication request packet */
202	static BOOL
203	licence_parse_authreq(STREAM s, uint8 token, uint8 signature)
204	{
205	uint16 tokenlen;
206
207	in_uint8s(s, 6); /* unknown: f8 3d 15 00 04 f6 */
208
209	in_uint16_le(s, tokenlen);
210	if (tokenlen != LICENCE_TOKEN_SIZE)
211	{
212	error("token len %d\n", tokenlen);
213	return False;
214	}
215
216	in_uint8p(s, *token, tokenlen);
217	in_uint8p(s, *signature, LICENCE_SIGNATURE_SIZE);
218
219	return s_check_end(s);
220	}
221
222	/* Process an authentication request packet */
223	static void
224	licence_process_authreq(STREAM s)
225	{
226	uint8 in_token, in_sig;
227	uint8 out_token[LICENCE_TOKEN_SIZE], decrypt_token[LICENCE_TOKEN_SIZE];
228	uint8 hwid[LICENCE_HWID_SIZE], crypt_hwid[LICENCE_HWID_SIZE];
229	uint8 sealed_buffer[LICENCE_TOKEN_SIZE + LICENCE_HWID_SIZE];
230	uint8 out_sig[LICENCE_SIGNATURE_SIZE];
231	RC4_KEY crypt_key;
232
233	/* Parse incoming packet and save the encrypted token */
234	licence_parse_authreq(s, &in_token, &in_sig);
235	memcpy(out_token, in_token, LICENCE_TOKEN_SIZE);
236
237	/* Decrypt the token. It should read TEST in Unicode. */
238	RC4_set_key(&crypt_key, 16, licence_key);
239	RC4(&crypt_key, LICENCE_TOKEN_SIZE, in_token, decrypt_token);
240
241	/* Generate a signature for a buffer of token and HWID */
242	licence_generate_hwid(hwid);
243	memcpy(sealed_buffer, decrypt_token, LICENCE_TOKEN_SIZE);
244	memcpy(sealed_buffer + LICENCE_TOKEN_SIZE, hwid, LICENCE_HWID_SIZE);
245	sec_sign(out_sig, 16, licence_sign_key, 16, sealed_buffer, sizeof(sealed_buffer));
246
247	/* Deliberately break signature if licencing disabled */
248	if (!licence)
249	memset(out_sig, 0, sizeof(out_sig));
250
251	/* Now encrypt the HWID */
252	RC4_set_key(&crypt_key, 16, licence_key);
253	RC4(&crypt_key, LICENCE_HWID_SIZE, hwid, crypt_hwid);
254
255	licence_send_authresp(out_token, crypt_hwid, out_sig);
256	}
257
258	/* Process an licence issue packet */
259	static void
260	licence_process_issue(STREAM s)
261	{
262	RC4_KEY crypt_key;
263	uint32 length;
264	uint16 check;
265
266	in_uint8s(s, 2); /* 3d 45 - unknown */
267	in_uint16_le(s, length);
268	if (!s_check_rem(s, length))
269	return;
270
271	RC4_set_key(&crypt_key, 16, licence_key);
272	RC4(&crypt_key, length, s->p, s->p);
273
274	in_uint16(s, check);
275	if (check != 0)
276	return;
277
278	licence_issued = True;
279	save_licence(s->p, length - 2);
280	}
281
282	/* Process a licence packet */
283	void
284	licence_process(STREAM s)
285	{
286	uint16 tag;
287
288	in_uint16_le(s, tag);
289	in_uint8s(s, 2); /* length */
290
291	switch (tag)
292	{
293	case LICENCE_TAG_DEMAND:
294	licence_process_demand(s);
295	break;
296
297	case LICENCE_TAG_AUTHREQ:
298	licence_process_authreq(s);
299	break;
300
301	case LICENCE_TAG_ISSUE:
302	licence_process_issue(s);
303	break;
304
305	case LICENCE_TAG_REISSUE:
306	break;
307
308	case LICENCE_TAG_RESULT:
309	break;
310
311	default:
312	unimpl("licence tag 0x%x\n", tag);
313	}
314	}