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	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	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			#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	astrand	82	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	astrand	64	licence_generate_hwid(uint8 * hwid)
53	matthewc	39	{
54			buf_out_uint32(hwid, 2);
55	astrand	77	strncpy((char *) (hwid + 4), hostname, LICENCE_HWID_SIZE - 4);
56	matthewc	39	}
57
58			/* Present an existing licence to the server */
59			static void
60	astrand	64	licence_present(uint8 * client_random, uint8 * rsa_data,
61	astrand	82	uint8 * licence_data, int licence_size, uint8 * hwid, uint8 * signature)
62	matthewc	39	{
63			uint32 sec_flags = SEC_LICENCE_NEG;
64	astrand	64	uint16 length =
65			16 + SEC_RANDOM_SIZE + SEC_MODULUS_SIZE + SEC_PADDING_SIZE +
66			licence_size + LICENCE_HWID_SIZE + LICENCE_SIGNATURE_SIZE;
67	matthewc	39	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	astrand	82	licence_send_request(uint8 * client_random, uint8 * rsa_data, char user, char host)
101	matty	10	{
102			uint32 sec_flags = SEC_LICENCE_NEG;
103			uint16 userlen = strlen(user) + 1;
104			uint16 hostlen = strlen(host) + 1;
105	jsorg71	60	uint16 length = 128 + userlen + hostlen;
106	matty	10	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	matthewc	39	out_uint16(s, 0);
115			out_uint16_le(s, 0xff01);
116	matty	10
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	matty	25	static void
137			licence_process_demand(STREAM s)
138	matty	10	{
139			uint8 null_data[SEC_MODULUS_SIZE];
140	matthewc	39	uint8 hwid[LICENCE_HWID_SIZE];
141			uint8 signature[LICENCE_SIGNATURE_SIZE];
142	matty	10	uint8 *server_random;
143	matthewc	39	uint8 *licence_data;
144			int licence_size;
145			RC4_KEY crypt_key;
146	matty	10
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	matthewc	39	licence_size = load_licence(&licence_data);
156			if (licence_size == -1)
157			{
158	astrand	82	licence_send_request(null_data, null_data, username, hostname);
159	matthewc	39	return;
160			}
161
162			/* Generate a signature for the HWID buffer */
163			licence_generate_hwid(hwid);
164	matthewc	61	sec_sign(signature, 16, licence_sign_key, 16, hwid, sizeof(hwid));
165	matthewc	39
166			/* Now encrypt the HWID */
167			RC4_set_key(&crypt_key, 16, licence_key);
168			RC4(&crypt_key, sizeof(hwid), hwid, hwid);
169
170	astrand	82	licence_present(null_data, null_data, licence_data, licence_size, hwid, signature);
171	matthewc	39	xfree(licence_data);
172	matty	10	}
173
174			/* Send an authentication response packet */
175	matty	25	static void
176	astrand	64	licence_send_authresp(uint8 * token, uint8 * crypt_hwid, uint8 * signature)
177	matty	10	{
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	matty	25	static BOOL
203	astrand	64	licence_parse_authreq(STREAM s, uint8 token, uint8 signature)
204	matty	10	{
205			uint16 tokenlen;
206
207	matty	24	in_uint8s(s, 6); /* unknown: f8 3d 15 00 04 f6 */
208	matty	10
209			in_uint16_le(s, tokenlen);
210			if (tokenlen != LICENCE_TOKEN_SIZE)
211			{
212	matty	30	error("token len %d\n", tokenlen);
213	matty	10	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	matty	25	static void
224			licence_process_authreq(STREAM s)
225	matty	10	{
226			uint8 in_token, in_sig;
227	astrand	82	uint8 out_token[LICENCE_TOKEN_SIZE], decrypt_token[LICENCE_TOKEN_SIZE];
228	matty	10	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	matthewc	39	licence_generate_hwid(hwid);
243	matty	10	memcpy(sealed_buffer, decrypt_token, LICENCE_TOKEN_SIZE);
244			memcpy(sealed_buffer + LICENCE_TOKEN_SIZE, hwid, LICENCE_HWID_SIZE);
245	astrand	82	sec_sign(out_sig, 16, licence_sign_key, 16, sealed_buffer, sizeof(sealed_buffer));
246	matty	10
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	matty	25	static void
260			licence_process_issue(STREAM s)
261	matty	10	{
262			RC4_KEY crypt_key;
263			uint32 length;
264			uint16 check;
265
266	matty	24	in_uint8s(s, 2); /* 3d 45 - unknown */
267	matty	10	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	matty	28	licence_issued = True;
279	astrand	64	save_licence(s->p, length - 2);
280	matty	10	}
281
282			/* Process a licence packet */
283	matty	25	void
284			licence_process(STREAM s)
285	matty	10	{
286			uint16 tag;
287
288			in_uint16_le(s, tag);
289	matty	24	in_uint8s(s, 2); /* length */
290	matty	10
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	matthewc	39	case LICENCE_TAG_REISSUE:
306			break;
307
308	matty	10	case LICENCE_TAG_RESULT:
309			break;
310
311			default:
312	matty	30	unimpl("licence tag 0x%x\n", tag);
313	matty	10	}
314			}