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