trunk/rdesktop/licence.c

/*
   rdesktop: A Remote Desktop Protocol client.
   RDP licensing negotiation
   Copyright (C) Matthew Chapman 1999-2000
   
   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];

/* 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;

        /* We should save the licence here */
        STATUS("Server issued licence.\n");
}

/* 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:
                        NOTIMP("licence tag 0x%x\n", tag);
        }
}
1	/*
2	rdesktop: A Remote Desktop Protocol client.
3	RDP licensing negotiation
4	Copyright (C) Matthew Chapman 1999-2000
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	/* Generate a session key and RC4 keys, given client and server randoms */
32	void licence_generate_keys(uint8 client_key, uint8 server_key,
33	uint8 *client_rsa)
34	{
35	uint8 session_key[48];
36	uint8 temp_hash[48];
37
38	/* Generate session key - two rounds of sec_hash_48 */
39	sec_hash_48(temp_hash, client_rsa, client_key, server_key, 65);
40	sec_hash_48(session_key, temp_hash, server_key, client_key, 65);
41
42	/* Store first 16 bytes of session key, for generating signatures */
43	memcpy(licence_sign_key, session_key, 16);
44
45	/* Generate RC4 key */
46	sec_hash_16(licence_key, &session_key[16], client_key, server_key);
47	}
48
49	/* Send a licence request packet */
50	static void licence_send_request(uint8 client_random, uint8 rsa_data,
51	char user, char host)
52	{
53	uint32 sec_flags = SEC_LICENCE_NEG;
54	uint16 userlen = strlen(user) + 1;
55	uint16 hostlen = strlen(host) + 1;
56	uint16 length = 120 + userlen + hostlen;
57	STREAM s;
58
59	s = sec_init(sec_flags, length + 2);
60
61	out_uint16_le(s, LICENCE_TAG_REQUEST);
62	out_uint16_le(s, length);
63
64	out_uint32_le(s, 1);
65	out_uint32_le(s, 0xff010000);
66
67	out_uint8p(s, client_random, SEC_RANDOM_SIZE);
68	out_uint16(s, 0);
69	out_uint16_le(s, (SEC_MODULUS_SIZE + SEC_PADDING_SIZE));
70	out_uint8p(s, rsa_data, SEC_MODULUS_SIZE);
71	out_uint8s(s, SEC_PADDING_SIZE);
72
73	out_uint16(s, LICENCE_TAG_USER);
74	out_uint16(s, userlen);
75	out_uint8p(s, user, userlen);
76
77	out_uint16(s, LICENCE_TAG_HOST);
78	out_uint16(s, hostlen);
79	out_uint8p(s, host, hostlen);
80
81	s_mark_end(s);
82	sec_send(s, sec_flags);
83	}
84
85	/* Process a licence demand packet */
86	static void licence_process_demand(STREAM s)
87	{
88	uint8 null_data[SEC_MODULUS_SIZE];
89	uint8 *server_random;
90
91	/* Retrieve the server random from the incoming packet */
92	in_uint8p(s, server_random, SEC_RANDOM_SIZE);
93
94	/* We currently use null client keys. This is a bit naughty but, hey,
95	the security of licence negotiation isn't exactly paramount. */
96	memset(null_data, 0, sizeof(null_data));
97	licence_generate_keys(null_data, server_random, null_data);
98
99	/* Send a certificate request back to the server */
100	licence_send_request(null_data, null_data, username, hostname);
101	}
102
103	/* Send an authentication response packet */
104	static void licence_send_authresp(uint8 token, uint8 crypt_hwid,
105	uint8 *signature)
106	{
107	uint32 sec_flags = SEC_LICENCE_NEG;
108	uint16 length = 58;
109	STREAM s;
110
111	s = sec_init(sec_flags, length + 2);
112
113	out_uint16_le(s, LICENCE_TAG_AUTHRESP);
114	out_uint16_le(s, length);
115
116	out_uint16_le(s, 1);
117	out_uint16_le(s, LICENCE_TOKEN_SIZE);
118	out_uint8p(s, token, LICENCE_TOKEN_SIZE);
119
120	out_uint16_le(s, 1);
121	out_uint16_le(s, LICENCE_HWID_SIZE);
122	out_uint8p(s, crypt_hwid, LICENCE_HWID_SIZE);
123
124	out_uint8p(s, signature, LICENCE_SIGNATURE_SIZE);
125
126	s_mark_end(s);
127	sec_send(s, sec_flags);
128	}
129
130	/* Parse an authentication request packet */
131	static BOOL licence_parse_authreq(STREAM s, uint8 token, uint8 signature)
132	{
133	uint16 tokenlen;
134
135	in_uint8s(s, 6); /* unknown: f8 3d 15 00 04 f6 */
136
137	in_uint16_le(s, tokenlen);
138	if (tokenlen != LICENCE_TOKEN_SIZE)
139	{
140	ERROR("token len %d\n", tokenlen);
141	return False;
142	}
143
144	in_uint8p(s, *token, tokenlen);
145	in_uint8p(s, *signature, LICENCE_SIGNATURE_SIZE);
146
147	return s_check_end(s);
148	}
149
150	/* Process an authentication request packet */
151	static void licence_process_authreq(STREAM s)
152	{
153	uint8 in_token, in_sig;
154	uint8 out_token[LICENCE_TOKEN_SIZE], decrypt_token[LICENCE_TOKEN_SIZE];
155	uint8 hwid[LICENCE_HWID_SIZE], crypt_hwid[LICENCE_HWID_SIZE];
156	uint8 sealed_buffer[LICENCE_TOKEN_SIZE + LICENCE_HWID_SIZE];
157	uint8 out_sig[LICENCE_SIGNATURE_SIZE];
158	RC4_KEY crypt_key;
159
160	/* Parse incoming packet and save the encrypted token */
161	licence_parse_authreq(s, &in_token, &in_sig);
162	memcpy(out_token, in_token, LICENCE_TOKEN_SIZE);
163
164	/* Decrypt the token. It should read TEST in Unicode. */
165	RC4_set_key(&crypt_key, 16, licence_key);
166	RC4(&crypt_key, LICENCE_TOKEN_SIZE, in_token, decrypt_token);
167
168	/* Construct HWID */
169	buf_out_uint32(hwid, 2);
170	strncpy(hwid + 4, hostname, LICENCE_HWID_SIZE - 4);
171
172	/* Generate a signature for a buffer of token and HWID */
173	memcpy(sealed_buffer, decrypt_token, LICENCE_TOKEN_SIZE);
174	memcpy(sealed_buffer + LICENCE_TOKEN_SIZE, hwid, LICENCE_HWID_SIZE);
175	sec_sign(out_sig, licence_sign_key, 16,
176	sealed_buffer, sizeof(sealed_buffer));
177
178	/* Deliberately break signature if licencing disabled */
179	if (!licence)
180	memset(out_sig, 0, sizeof(out_sig));
181
182	/* Now encrypt the HWID */
183	RC4_set_key(&crypt_key, 16, licence_key);
184	RC4(&crypt_key, LICENCE_HWID_SIZE, hwid, crypt_hwid);
185
186	licence_send_authresp(out_token, crypt_hwid, out_sig);
187	}
188
189	/* Process an licence issue packet */
190	static void licence_process_issue(STREAM s)
191	{
192	RC4_KEY crypt_key;
193	uint32 length;
194	uint16 check;
195
196	in_uint8s(s, 2); /* 3d 45 - unknown */
197	in_uint16_le(s, length);
198	if (!s_check_rem(s, length))
199	return;
200
201	RC4_set_key(&crypt_key, 16, licence_key);
202	RC4(&crypt_key, length, s->p, s->p);
203
204	in_uint16(s, check);
205	if (check != 0)
206	return;
207
208	/* We should save the licence here */
209	STATUS("Server issued licence.\n");
210	}
211
212	/* Process a licence packet */
213	void licence_process(STREAM s)
214	{
215	uint16 tag;
216
217	in_uint16_le(s, tag);
218	in_uint8s(s, 2); /* length */
219
220	switch (tag)
221	{
222	case LICENCE_TAG_DEMAND:
223	licence_process_demand(s);
224	break;
225
226	case LICENCE_TAG_AUTHREQ:
227	licence_process_authreq(s);
228	break;
229
230	case LICENCE_TAG_ISSUE:
231	licence_process_issue(s);
232	break;
233
234	case LICENCE_TAG_RESULT:
235	break;
236
237	default:
238	NOTIMP("licence tag 0x%x\n", tag);
239	}
240	}