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 g_username[16];
extern char hostname[16];

static uint8 g_licence_key[16];
static uint8 g_licence_sign_key[16];

BOOL g_licence_issued = False;

/* Generate a session key and RC4 keys, given client and server randoms */
static void
licence_generate_keys(uint8 * client_random, uint8 * server_random, uint8 * pre_master_secret)
{
        uint8 master_secret[48];
        uint8 key_block[48];

        /* Generate master secret and then key material */
        sec_hash_48(master_secret, pre_master_secret, client_random, server_random, 'A');
        sec_hash_48(key_block, master_secret, server_random, client_random, 'A');

        /* Store first 16 bytes of session key as MAC secret */
        memcpy(g_licence_sign_key, key_block, 16);

        /* Generate RC4 key from next 16 bytes */
        sec_hash_16(g_licence_key, &key_block[16], client_random, server_random);
}

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_uint8(s, LICENCE_TAG_PRESENT);
        out_uint8(s, 2);        /* version */
        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_uint8(s, LICENCE_TAG_REQUEST);
        out_uint8(s, 2);        /* version */
        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_le(s, LICENCE_TAG_USER);
        out_uint16_le(s, userlen);
        out_uint8p(s, user, userlen);

        out_uint16_le(s, LICENCE_TAG_HOST);
        out_uint16_le(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;
        uint8 signature[LICENCE_SIGNATURE_SIZE];
        uint8 hwid[LICENCE_HWID_SIZE];
        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 > 0)
        {
                /* Generate a signature for the HWID buffer */
                licence_generate_hwid(hwid);
                sec_sign(signature, 16, g_licence_sign_key, 16, hwid, sizeof(hwid));

                /* Now encrypt the HWID */
                RC4_set_key(&crypt_key, 16, g_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;
        }

        licence_send_request(null_data, null_data, g_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_uint8(s, LICENCE_TAG_AUTHRESP);
        out_uint8(s, 2);        /* version */
        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, g_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, g_licence_sign_key, 16, sealed_buffer, sizeof(sealed_buffer));

        /* Now encrypt the HWID */
        RC4_set_key(&crypt_key, 16, g_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;
        int i;

        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, g_licence_key);
        RC4(&crypt_key, length, s->p, s->p);

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

        g_licence_issued = True;

        in_uint8s(s, 2);        /* pad */

        /* advance to fourth string */
        length = 0;
        for (i = 0; i < 4; i++)
        {
                in_uint8s(s, length);
                in_uint32_le(s, length);
                if (!s_check_rem(s, length))
                        return;
        }

        g_licence_issued = True;
        save_licence(s->p, length);
}

/* Process a licence packet */
void
licence_process(STREAM s)
{
        uint8 tag;

        in_uint8(s, tag);
        in_uint8s(s, 3);        /* version, 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:
                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 1999-2002
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
23	#ifdef WITH_OPENSSL
24	#include <openssl/rc4.h>
25	#else
26	#include "crypto/rc4.h"
27	#endif
28
29	extern char g_username[16];
30	extern char hostname[16];
31
32	static uint8 g_licence_key[16];
33	static uint8 g_licence_sign_key[16];
34
35	BOOL g_licence_issued = False;
36
37	/* Generate a session key and RC4 keys, given client and server randoms */
38	static void
39	licence_generate_keys(uint8 * client_random, uint8 * server_random, uint8 * pre_master_secret)
40	{
41	uint8 master_secret[48];
42	uint8 key_block[48];
43
44	/* Generate master secret and then key material */
45	sec_hash_48(master_secret, pre_master_secret, client_random, server_random, 'A');
46	sec_hash_48(key_block, master_secret, server_random, client_random, 'A');
47
48	/* Store first 16 bytes of session key as MAC secret */
49	memcpy(g_licence_sign_key, key_block, 16);
50
51	/* Generate RC4 key from next 16 bytes */
52	sec_hash_16(g_licence_key, &key_block[16], client_random, server_random);
53	}
54
55	static void
56	licence_generate_hwid(uint8 * hwid)
57	{
58	buf_out_uint32(hwid, 2);
59	strncpy((char *) (hwid + 4), hostname, LICENCE_HWID_SIZE - 4);
60	}
61
62	/* Present an existing licence to the server */
63	static void
64	licence_present(uint8 * client_random, uint8 * rsa_data,
65	uint8 * licence_data, int licence_size, uint8 * hwid, uint8 * signature)
66	{
67	uint32 sec_flags = SEC_LICENCE_NEG;
68	uint16 length =
69	16 + SEC_RANDOM_SIZE + SEC_MODULUS_SIZE + SEC_PADDING_SIZE +
70	licence_size + LICENCE_HWID_SIZE + LICENCE_SIGNATURE_SIZE;
71	STREAM s;
72
73	s = sec_init(sec_flags, length + 4);
74
75	out_uint8(s, LICENCE_TAG_PRESENT);
76	out_uint8(s, 2); /* version */
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
103	/* Send a licence request packet */
104	static void
105	licence_send_request(uint8 * client_random, uint8 * rsa_data, char user, char host)
106	{
107	uint32 sec_flags = SEC_LICENCE_NEG;
108	uint16 userlen = strlen(user) + 1;
109	uint16 hostlen = strlen(host) + 1;
110	uint16 length = 128 + userlen + hostlen;
111	STREAM s;
112
113	s = sec_init(sec_flags, length + 2);
114
115	out_uint8(s, LICENCE_TAG_REQUEST);
116	out_uint8(s, 2); /* version */
117	out_uint16_le(s, length);
118
119	out_uint32_le(s, 1);
120	out_uint16(s, 0);
121	out_uint16_le(s, 0xff01);
122
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_le(s, LICENCE_TAG_USER);
130	out_uint16_le(s, userlen);
131	out_uint8p(s, user, userlen);
132
133	out_uint16_le(s, LICENCE_TAG_HOST);
134	out_uint16_le(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	static void
143	licence_process_demand(STREAM s)
144	{
145	uint8 null_data[SEC_MODULUS_SIZE];
146	uint8 *server_random;
147	uint8 signature[LICENCE_SIGNATURE_SIZE];
148	uint8 hwid[LICENCE_HWID_SIZE];
149	uint8 *licence_data;
150	int licence_size;
151	RC4_KEY crypt_key;
152
153	/* Retrieve the server random from the incoming packet */
154	in_uint8p(s, server_random, SEC_RANDOM_SIZE);
155
156	/* We currently use null client keys. This is a bit naughty but, hey,
157	the security of licence negotiation isn't exactly paramount. */
158	memset(null_data, 0, sizeof(null_data));
159	licence_generate_keys(null_data, server_random, null_data);
160
161	licence_size = load_licence(&licence_data);
162	if (licence_size > 0)
163	{
164	/* Generate a signature for the HWID buffer */
165	licence_generate_hwid(hwid);
166	sec_sign(signature, 16, g_licence_sign_key, 16, hwid, sizeof(hwid));
167
168	/* Now encrypt the HWID */
169	RC4_set_key(&crypt_key, 16, g_licence_key);
170	RC4(&crypt_key, sizeof(hwid), hwid, hwid);
171
172	licence_present(null_data, null_data, licence_data, licence_size, hwid, signature);
173	xfree(licence_data);
174	return;
175	}
176
177	licence_send_request(null_data, null_data, g_username, hostname);
178	}
179
180	/* Send an authentication response packet */
181	static void
182	licence_send_authresp(uint8 * token, uint8 * crypt_hwid, uint8 * signature)
183	{
184	uint32 sec_flags = SEC_LICENCE_NEG;
185	uint16 length = 58;
186	STREAM s;
187
188	s = sec_init(sec_flags, length + 2);
189
190	out_uint8(s, LICENCE_TAG_AUTHRESP);
191	out_uint8(s, 2); /* version */
192	out_uint16_le(s, length);
193
194	out_uint16_le(s, 1);
195	out_uint16_le(s, LICENCE_TOKEN_SIZE);
196	out_uint8p(s, token, LICENCE_TOKEN_SIZE);
197
198	out_uint16_le(s, 1);
199	out_uint16_le(s, LICENCE_HWID_SIZE);
200	out_uint8p(s, crypt_hwid, LICENCE_HWID_SIZE);
201
202	out_uint8p(s, signature, LICENCE_SIGNATURE_SIZE);
203
204	s_mark_end(s);
205	sec_send(s, sec_flags);
206	}
207
208	/* Parse an authentication request packet */
209	static BOOL
210	licence_parse_authreq(STREAM s, uint8 token, uint8 signature)
211	{
212	uint16 tokenlen;
213
214	in_uint8s(s, 6); /* unknown: f8 3d 15 00 04 f6 */
215
216	in_uint16_le(s, tokenlen);
217	if (tokenlen != LICENCE_TOKEN_SIZE)
218	{
219	error("token len %d\n", tokenlen);
220	return False;
221	}
222
223	in_uint8p(s, *token, tokenlen);
224	in_uint8p(s, *signature, LICENCE_SIGNATURE_SIZE);
225
226	return s_check_end(s);
227	}
228
229	/* Process an authentication request packet */
230	static void
231	licence_process_authreq(STREAM s)
232	{
233	uint8 in_token, in_sig;
234	uint8 out_token[LICENCE_TOKEN_SIZE], decrypt_token[LICENCE_TOKEN_SIZE];
235	uint8 hwid[LICENCE_HWID_SIZE], crypt_hwid[LICENCE_HWID_SIZE];
236	uint8 sealed_buffer[LICENCE_TOKEN_SIZE + LICENCE_HWID_SIZE];
237	uint8 out_sig[LICENCE_SIGNATURE_SIZE];
238	RC4_KEY crypt_key;
239
240	/* Parse incoming packet and save the encrypted token */
241	licence_parse_authreq(s, &in_token, &in_sig);
242	memcpy(out_token, in_token, LICENCE_TOKEN_SIZE);
243
244	/* Decrypt the token. It should read TEST in Unicode. */
245	RC4_set_key(&crypt_key, 16, g_licence_key);
246	RC4(&crypt_key, LICENCE_TOKEN_SIZE, in_token, decrypt_token);
247
248	/* Generate a signature for a buffer of token and HWID */
249	licence_generate_hwid(hwid);
250	memcpy(sealed_buffer, decrypt_token, LICENCE_TOKEN_SIZE);
251	memcpy(sealed_buffer + LICENCE_TOKEN_SIZE, hwid, LICENCE_HWID_SIZE);
252	sec_sign(out_sig, 16, g_licence_sign_key, 16, sealed_buffer, sizeof(sealed_buffer));
253
254	/* Now encrypt the HWID */
255	RC4_set_key(&crypt_key, 16, g_licence_key);
256	RC4(&crypt_key, LICENCE_HWID_SIZE, hwid, crypt_hwid);
257
258	licence_send_authresp(out_token, crypt_hwid, out_sig);
259	}
260
261	/* Process an licence issue packet */
262	static void
263	licence_process_issue(STREAM s)
264	{
265	RC4_KEY crypt_key;
266	uint32 length;
267	uint16 check;
268	int i;
269
270	in_uint8s(s, 2); /* 3d 45 - unknown */
271	in_uint16_le(s, length);
272	if (!s_check_rem(s, length))
273	return;
274
275	RC4_set_key(&crypt_key, 16, g_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	g_licence_issued = True;
283
284	in_uint8s(s, 2); /* pad */
285
286	/* advance to fourth string */
287	length = 0;
288	for (i = 0; i < 4; i++)
289	{
290	in_uint8s(s, length);
291	in_uint32_le(s, length);
292	if (!s_check_rem(s, length))
293	return;
294	}
295
296	g_licence_issued = True;
297	save_licence(s->p, length);
298	}
299
300	/* Process a licence packet */
301	void
302	licence_process(STREAM s)
303	{
304	uint8 tag;
305
306	in_uint8(s, tag);
307	in_uint8s(s, 3); /* version, length */
308
309	switch (tag)
310	{
311	case LICENCE_TAG_DEMAND:
312	licence_process_demand(s);
313	break;
314
315	case LICENCE_TAG_AUTHREQ:
316	licence_process_authreq(s);
317	break;
318
319	case LICENCE_TAG_ISSUE:
320	licence_process_issue(s);
321	break;
322
323	case LICENCE_TAG_REISSUE:
324	case LICENCE_TAG_RESULT:
325	break;
326
327	default:
328	unimpl("licence tag 0x%x\n", tag);
329	}
330	}