trunk/rdesktop/licence.c

/*
   rdesktop: A Remote Desktop Protocol client.
   RDP licensing negotiation
   Copyright (C) Matthew Chapman 1999-2005
   
   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 <openssl/rc4.h>

extern char g_username[16];
extern char g_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), g_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, g_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	matty	10	/*
2			rdesktop: A Remote Desktop Protocol client.
3			RDP licensing negotiation
4	stargo	828	Copyright (C) Matthew Chapman 1999-2005
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	astrand	293	#include <openssl/rc4.h>
23	matty	10
24	jsorg71	437	extern char g_username[16];
25	jsorg71	710	extern char g_hostname[16];
26	matty	10
27	jsorg71	380	static uint8 g_licence_key[16];
28			static uint8 g_licence_sign_key[16];
29	matty	10
30	jsorg71	380	BOOL g_licence_issued = False;
31	matty	28
32	matty	10	/* Generate a session key and RC4 keys, given client and server randoms */
33	matthewc	39	static void
34	matthewc	699	licence_generate_keys(uint8 * client_random, uint8 * server_random, uint8 * pre_master_secret)
35	matty	10	{
36	matthewc	699	uint8 master_secret[48];
37			uint8 key_block[48];
38	matty	10
39	matthewc	699	/* Generate master secret and then key material */
40			sec_hash_48(master_secret, pre_master_secret, client_random, server_random, 'A');
41	astrand	706	sec_hash_48(key_block, master_secret, server_random, client_random, 'A');
42	matty	10
43	matthewc	699	/* Store first 16 bytes of session key as MAC secret */
44			memcpy(g_licence_sign_key, key_block, 16);
45	matty	10
46	matthewc	699	/* Generate RC4 key from next 16 bytes */
47			sec_hash_16(g_licence_key, &key_block[16], client_random, server_random);
48	matty	10	}
49
50	matthewc	39	static void
51	astrand	64	licence_generate_hwid(uint8 * hwid)
52	matthewc	39	{
53			buf_out_uint32(hwid, 2);
54	jsorg71	710	strncpy((char *) (hwid + 4), g_hostname, LICENCE_HWID_SIZE - 4);
55	matthewc	39	}
56
57			/* Present an existing licence to the server */
58			static void
59	astrand	64	licence_present(uint8 * client_random, uint8 * rsa_data,
60	astrand	82	uint8 * licence_data, int licence_size, uint8 * hwid, uint8 * signature)
61	matthewc	39	{
62			uint32 sec_flags = SEC_LICENCE_NEG;
63	astrand	64	uint16 length =
64			16 + SEC_RANDOM_SIZE + SEC_MODULUS_SIZE + SEC_PADDING_SIZE +
65			licence_size + LICENCE_HWID_SIZE + LICENCE_SIGNATURE_SIZE;
66	matthewc	39	STREAM s;
67
68			s = sec_init(sec_flags, length + 4);
69
70	matthewc	366	out_uint8(s, LICENCE_TAG_PRESENT);
71	forsberg	408	out_uint8(s, 2); /* version */
72	matthewc	39	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	matthewc	366	out_uint8(s, LICENCE_TAG_REQUEST);
111	forsberg	408	out_uint8(s, 2); /* version */
112	matty	10	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	matthewc	365	out_uint16_le(s, LICENCE_TAG_USER);
125			out_uint16_le(s, userlen);
126	matty	10	out_uint8p(s, user, userlen);
127
128	matthewc	365	out_uint16_le(s, LICENCE_TAG_HOST);
129			out_uint16_le(s, hostlen);
130	matty	10	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	190	uint8 *server_random;
142			uint8 signature[LICENCE_SIGNATURE_SIZE];
143	matthewc	39	uint8 hwid[LICENCE_HWID_SIZE];
144			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	matthewc	367	if (licence_size > 0)
158	matthewc	39	{
159	matthewc	159	/* Generate a signature for the HWID buffer */
160			licence_generate_hwid(hwid);
161	jsorg71	380	sec_sign(signature, 16, g_licence_sign_key, 16, hwid, sizeof(hwid));
162	matthewc	159
163			/* Now encrypt the HWID */
164	jsorg71	380	RC4_set_key(&crypt_key, 16, g_licence_key);
165	matthewc	159	RC4(&crypt_key, sizeof(hwid), hwid, hwid);
166
167			licence_present(null_data, null_data, licence_data, licence_size, hwid, signature);
168			xfree(licence_data);
169	matthewc	39	return;
170			}
171
172	jsorg71	710	licence_send_request(null_data, null_data, g_username, g_hostname);
173	matty	10	}
174
175			/* Send an authentication response packet */
176	matty	25	static void
177	astrand	64	licence_send_authresp(uint8 * token, uint8 * crypt_hwid, uint8 * signature)
178	matty	10	{
179			uint32 sec_flags = SEC_LICENCE_NEG;
180			uint16 length = 58;
181			STREAM s;
182
183			s = sec_init(sec_flags, length + 2);
184
185	matthewc	366	out_uint8(s, LICENCE_TAG_AUTHRESP);
186	forsberg	408	out_uint8(s, 2); /* version */
187	matty	10	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	astrand	64	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	astrand	82	uint8 out_token[LICENCE_TOKEN_SIZE], decrypt_token[LICENCE_TOKEN_SIZE];
230	matty	10	uint8 hwid[LICENCE_HWID_SIZE], crypt_hwid[LICENCE_HWID_SIZE];
231			uint8 sealed_buffer[LICENCE_TOKEN_SIZE + LICENCE_HWID_SIZE];
232			uint8 out_sig[LICENCE_SIGNATURE_SIZE];
233			RC4_KEY crypt_key;
234
235			/* Parse incoming packet and save the encrypted token */
236			licence_parse_authreq(s, &in_token, &in_sig);
237			memcpy(out_token, in_token, LICENCE_TOKEN_SIZE);
238
239			/* Decrypt the token. It should read TEST in Unicode. */
240	jsorg71	380	RC4_set_key(&crypt_key, 16, g_licence_key);
241	matty	10	RC4(&crypt_key, LICENCE_TOKEN_SIZE, in_token, decrypt_token);
242
243			/* Generate a signature for a buffer of token and HWID */
244	matthewc	39	licence_generate_hwid(hwid);
245	matty	10	memcpy(sealed_buffer, decrypt_token, LICENCE_TOKEN_SIZE);
246			memcpy(sealed_buffer + LICENCE_TOKEN_SIZE, hwid, LICENCE_HWID_SIZE);
247	jsorg71	380	sec_sign(out_sig, 16, g_licence_sign_key, 16, sealed_buffer, sizeof(sealed_buffer));
248	matty	10
249			/* Now encrypt the HWID */
250	jsorg71	380	RC4_set_key(&crypt_key, 16, g_licence_key);
251	matty	10	RC4(&crypt_key, LICENCE_HWID_SIZE, hwid, crypt_hwid);
252
253			licence_send_authresp(out_token, crypt_hwid, out_sig);
254			}
255
256			/* Process an licence issue packet */
257	matty	25	static void
258			licence_process_issue(STREAM s)
259	matty	10	{
260			RC4_KEY crypt_key;
261			uint32 length;
262			uint16 check;
263	matthewc	367	int i;
264	matty	10
265	matty	24	in_uint8s(s, 2); /* 3d 45 - unknown */
266	matty	10	in_uint16_le(s, length);
267			if (!s_check_rem(s, length))
268			return;
269
270	jsorg71	380	RC4_set_key(&crypt_key, 16, g_licence_key);
271	matty	10	RC4(&crypt_key, length, s->p, s->p);
272
273			in_uint16(s, check);
274			if (check != 0)
275			return;
276
277	jsorg71	380	g_licence_issued = True;
278	matthewc	367
279			in_uint8s(s, 2); /* pad */
280
281			/* advance to fourth string */
282			length = 0;
283			for (i = 0; i < 4; i++)
284			{
285			in_uint8s(s, length);
286			in_uint32_le(s, length);
287			if (!s_check_rem(s, length))
288			return;
289			}
290
291	jsorg71	380	g_licence_issued = True;
292	matthewc	367	save_licence(s->p, length);
293	matty	10	}
294
295			/* Process a licence packet */
296	matty	25	void
297			licence_process(STREAM s)
298	matty	10	{
299	matthewc	364	uint8 tag;
300	matty	10
301	matthewc	364	in_uint8(s, tag);
302			in_uint8s(s, 3); /* version, length */
303	matty	10
304			switch (tag)
305			{
306			case LICENCE_TAG_DEMAND:
307			licence_process_demand(s);
308			break;
309
310			case LICENCE_TAG_AUTHREQ:
311			licence_process_authreq(s);
312			break;
313
314			case LICENCE_TAG_ISSUE:
315			licence_process_issue(s);
316			break;
317
318	matthewc	39	case LICENCE_TAG_REISSUE:
319	matty	10	case LICENCE_TAG_RESULT:
320			break;
321
322			default:
323	matty	30	unimpl("licence tag 0x%x\n", tag);
324	matty	10	}
325			}