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 */
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);
}

/* 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 = 120 + 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_uint32_le(s, 0xff010000);

        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 *server_random;

        /* 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);

        /* Send a certificate request back to the server */
        licence_send_request(null_data, null_data, 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_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);

        /* Construct HWID */
        buf_out_uint32(hwid, 2);
        strncpy(hwid + 4, hostname, LICENCE_HWID_SIZE - 4);

        /* Generate a signature for a buffer of token and HWID */
        memcpy(sealed_buffer, decrypt_token, LICENCE_TOKEN_SIZE);
        memcpy(sealed_buffer + LICENCE_TOKEN_SIZE, hwid, LICENCE_HWID_SIZE);
        sec_sign(out_sig, 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;

        /* We should save the licence here */
}

/* 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_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	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	/* Send a licence request packet */
52	static void
53	licence_send_request(uint8 client_random, uint8 rsa_data,
54	char user, char host)
55	{
56	uint32 sec_flags = SEC_LICENCE_NEG;
57	uint16 userlen = strlen(user) + 1;
58	uint16 hostlen = strlen(host) + 1;
59	uint16 length = 120 + userlen + hostlen;
60	STREAM s;
61
62	s = sec_init(sec_flags, length + 2);
63
64	out_uint16_le(s, LICENCE_TAG_REQUEST);
65	out_uint16_le(s, length);
66
67	out_uint32_le(s, 1);
68	out_uint32_le(s, 0xff010000);
69
70	out_uint8p(s, client_random, SEC_RANDOM_SIZE);
71	out_uint16(s, 0);
72	out_uint16_le(s, (SEC_MODULUS_SIZE + SEC_PADDING_SIZE));
73	out_uint8p(s, rsa_data, SEC_MODULUS_SIZE);
74	out_uint8s(s, SEC_PADDING_SIZE);
75
76	out_uint16(s, LICENCE_TAG_USER);
77	out_uint16(s, userlen);
78	out_uint8p(s, user, userlen);
79
80	out_uint16(s, LICENCE_TAG_HOST);
81	out_uint16(s, hostlen);
82	out_uint8p(s, host, hostlen);
83
84	s_mark_end(s);
85	sec_send(s, sec_flags);
86	}
87
88	/* Process a licence demand packet */
89	static void
90	licence_process_demand(STREAM s)
91	{
92	uint8 null_data[SEC_MODULUS_SIZE];
93	uint8 *server_random;
94
95	/* Retrieve the server random from the incoming packet */
96	in_uint8p(s, server_random, SEC_RANDOM_SIZE);
97
98	/* We currently use null client keys. This is a bit naughty but, hey,
99	the security of licence negotiation isn't exactly paramount. */
100	memset(null_data, 0, sizeof(null_data));
101	licence_generate_keys(null_data, server_random, null_data);
102
103	/* Send a certificate request back to the server */
104	licence_send_request(null_data, null_data, username, hostname);
105	}
106
107	/* Send an authentication response packet */
108	static void
109	licence_send_authresp(uint8 token, uint8 crypt_hwid, uint8 *signature)
110	{
111	uint32 sec_flags = SEC_LICENCE_NEG;
112	uint16 length = 58;
113	STREAM s;
114
115	s = sec_init(sec_flags, length + 2);
116
117	out_uint16_le(s, LICENCE_TAG_AUTHRESP);
118	out_uint16_le(s, length);
119
120	out_uint16_le(s, 1);
121	out_uint16_le(s, LICENCE_TOKEN_SIZE);
122	out_uint8p(s, token, LICENCE_TOKEN_SIZE);
123
124	out_uint16_le(s, 1);
125	out_uint16_le(s, LICENCE_HWID_SIZE);
126	out_uint8p(s, crypt_hwid, LICENCE_HWID_SIZE);
127
128	out_uint8p(s, signature, LICENCE_SIGNATURE_SIZE);
129
130	s_mark_end(s);
131	sec_send(s, sec_flags);
132	}
133
134	/* Parse an authentication request packet */
135	static BOOL
136	licence_parse_authreq(STREAM s, uint8 token, uint8 signature)
137	{
138	uint16 tokenlen;
139
140	in_uint8s(s, 6); /* unknown: f8 3d 15 00 04 f6 */
141
142	in_uint16_le(s, tokenlen);
143	if (tokenlen != LICENCE_TOKEN_SIZE)
144	{
145	error("token len %d\n", tokenlen);
146	return False;
147	}
148
149	in_uint8p(s, *token, tokenlen);
150	in_uint8p(s, *signature, LICENCE_SIGNATURE_SIZE);
151
152	return s_check_end(s);
153	}
154
155	/* Process an authentication request packet */
156	static void
157	licence_process_authreq(STREAM s)
158	{
159	uint8 in_token, in_sig;
160	uint8 out_token[LICENCE_TOKEN_SIZE],
161	decrypt_token[LICENCE_TOKEN_SIZE];
162	uint8 hwid[LICENCE_HWID_SIZE], crypt_hwid[LICENCE_HWID_SIZE];
163	uint8 sealed_buffer[LICENCE_TOKEN_SIZE + LICENCE_HWID_SIZE];
164	uint8 out_sig[LICENCE_SIGNATURE_SIZE];
165	RC4_KEY crypt_key;
166
167	/* Parse incoming packet and save the encrypted token */
168	licence_parse_authreq(s, &in_token, &in_sig);
169	memcpy(out_token, in_token, LICENCE_TOKEN_SIZE);
170
171	/* Decrypt the token. It should read TEST in Unicode. */
172	RC4_set_key(&crypt_key, 16, licence_key);
173	RC4(&crypt_key, LICENCE_TOKEN_SIZE, in_token, decrypt_token);
174
175	/* Construct HWID */
176	buf_out_uint32(hwid, 2);
177	strncpy(hwid + 4, hostname, LICENCE_HWID_SIZE - 4);
178
179	/* Generate a signature for a buffer of token and HWID */
180	memcpy(sealed_buffer, decrypt_token, LICENCE_TOKEN_SIZE);
181	memcpy(sealed_buffer + LICENCE_TOKEN_SIZE, hwid, LICENCE_HWID_SIZE);
182	sec_sign(out_sig, licence_sign_key, 16,
183	sealed_buffer, sizeof(sealed_buffer));
184
185	/* Deliberately break signature if licencing disabled */
186	if (!licence)
187	memset(out_sig, 0, sizeof(out_sig));
188
189	/* Now encrypt the HWID */
190	RC4_set_key(&crypt_key, 16, licence_key);
191	RC4(&crypt_key, LICENCE_HWID_SIZE, hwid, crypt_hwid);
192
193	licence_send_authresp(out_token, crypt_hwid, out_sig);
194	}
195
196	/* Process an licence issue packet */
197	static void
198	licence_process_issue(STREAM s)
199	{
200	RC4_KEY crypt_key;
201	uint32 length;
202	uint16 check;
203
204	in_uint8s(s, 2); /* 3d 45 - unknown */
205	in_uint16_le(s, length);
206	if (!s_check_rem(s, length))
207	return;
208
209	RC4_set_key(&crypt_key, 16, licence_key);
210	RC4(&crypt_key, length, s->p, s->p);
211
212	in_uint16(s, check);
213	if (check != 0)
214	return;
215
216	licence_issued = True;
217
218	/* We should save the licence here */
219	}
220
221	/* Process a licence packet */
222	void
223	licence_process(STREAM s)
224	{
225	uint16 tag;
226
227	in_uint16_le(s, tag);
228	in_uint8s(s, 2); /* length */
229
230	switch (tag)
231	{
232	case LICENCE_TAG_DEMAND:
233	licence_process_demand(s);
234	break;
235
236	case LICENCE_TAG_AUTHREQ:
237	licence_process_authreq(s);
238	break;
239
240	case LICENCE_TAG_ISSUE:
241	licence_process_issue(s);
242	break;
243
244	case LICENCE_TAG_RESULT:
245	break;
246
247	default:
248	unimpl("licence tag 0x%x\n", tag);
249	}
250	}