/[rdesktop]/sourceforge.net/trunk/rdesktop/licence.c
This is repository of my old source code which isn't updated any more. Go to git.rot13.org for current projects!
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Annotation of /sourceforge.net/trunk/rdesktop/licence.c

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Revision 699 - (hide annotations)
Sun May 16 11:18:20 2004 UTC (20 years ago) by matthewc
File MIME type: text/plain
File size: 8538 byte(s)
Document differences between RDP encryption and SSLv3, and bring some
of the terminology in line with the SSLv3 specification.

1 matty 10 /*
2     rdesktop: A Remote Desktop Protocol client.
3     RDP licensing negotiation
4 matthewc 207 Copyright (C) Matthew Chapman 1999-2002
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
23     #ifdef WITH_OPENSSL
24     #include <openssl/rc4.h>
25     #else
26 matty 10 #include "crypto/rc4.h"
27 astrand 293 #endif
28 matty 10
29 jsorg71 437 extern char g_username[16];
30 matty 10 extern char hostname[16];
31    
32 jsorg71 380 static uint8 g_licence_key[16];
33     static uint8 g_licence_sign_key[16];
34 matty 10
35 jsorg71 380 BOOL g_licence_issued = False;
36 matty 28
37 matty 10 /* Generate a session key and RC4 keys, given client and server randoms */
38 matthewc 39 static void
39 matthewc 699 licence_generate_keys(uint8 * client_random, uint8 * server_random, uint8 * pre_master_secret)
40 matty 10 {
41 matthewc 699 uint8 master_secret[48];
42     uint8 key_block[48];
43 matty 10
44 matthewc 699 /* Generate master secret and then key material */
45     sec_hash_48(master_secret, pre_master_secret, client_random, server_random, 'A');
46     sec_hash_48(key_block, master_secret, server_random, client_random, 'A');
47 matty 10
48 matthewc 699 /* Store first 16 bytes of session key as MAC secret */
49     memcpy(g_licence_sign_key, key_block, 16);
50 matty 10
51 matthewc 699 /* Generate RC4 key from next 16 bytes */
52     sec_hash_16(g_licence_key, &key_block[16], client_random, server_random);
53 matty 10 }
54    
55 matthewc 39 static void
56 astrand 64 licence_generate_hwid(uint8 * hwid)
57 matthewc 39 {
58     buf_out_uint32(hwid, 2);
59 astrand 77 strncpy((char *) (hwid + 4), hostname, LICENCE_HWID_SIZE - 4);
60 matthewc 39 }
61    
62     /* Present an existing licence to the server */
63     static void
64 astrand 64 licence_present(uint8 * client_random, uint8 * rsa_data,
65 astrand 82 uint8 * licence_data, int licence_size, uint8 * hwid, uint8 * signature)
66 matthewc 39 {
67     uint32 sec_flags = SEC_LICENCE_NEG;
68 astrand 64 uint16 length =
69     16 + SEC_RANDOM_SIZE + SEC_MODULUS_SIZE + SEC_PADDING_SIZE +
70     licence_size + LICENCE_HWID_SIZE + LICENCE_SIGNATURE_SIZE;
71 matthewc 39 STREAM s;
72    
73     s = sec_init(sec_flags, length + 4);
74    
75 matthewc 366 out_uint8(s, LICENCE_TAG_PRESENT);
76 forsberg 408 out_uint8(s, 2); /* version */
77 matthewc 39 out_uint16_le(s, length);
78    
79     out_uint32_le(s, 1);
80     out_uint16(s, 0);
81     out_uint16_le(s, 0x0201);
82    
83     out_uint8p(s, client_random, SEC_RANDOM_SIZE);
84     out_uint16(s, 0);
85     out_uint16_le(s, (SEC_MODULUS_SIZE + SEC_PADDING_SIZE));
86     out_uint8p(s, rsa_data, SEC_MODULUS_SIZE);
87     out_uint8s(s, SEC_PADDING_SIZE);
88    
89     out_uint16_le(s, 1);
90     out_uint16_le(s, licence_size);
91     out_uint8p(s, licence_data, licence_size);
92    
93     out_uint16_le(s, 1);
94     out_uint16_le(s, LICENCE_HWID_SIZE);
95     out_uint8p(s, hwid, LICENCE_HWID_SIZE);
96    
97     out_uint8p(s, signature, LICENCE_SIGNATURE_SIZE);
98    
99     s_mark_end(s);
100     sec_send(s, sec_flags);
101     }
102    
103 matty 10 /* Send a licence request packet */
104 matty 25 static void
105 astrand 82 licence_send_request(uint8 * client_random, uint8 * rsa_data, char *user, char *host)
106 matty 10 {
107     uint32 sec_flags = SEC_LICENCE_NEG;
108     uint16 userlen = strlen(user) + 1;
109     uint16 hostlen = strlen(host) + 1;
110 jsorg71 60 uint16 length = 128 + userlen + hostlen;
111 matty 10 STREAM s;
112    
113     s = sec_init(sec_flags, length + 2);
114    
115 matthewc 366 out_uint8(s, LICENCE_TAG_REQUEST);
116 forsberg 408 out_uint8(s, 2); /* version */
117 matty 10 out_uint16_le(s, length);
118    
119     out_uint32_le(s, 1);
120 matthewc 39 out_uint16(s, 0);
121     out_uint16_le(s, 0xff01);
122 matty 10
123     out_uint8p(s, client_random, SEC_RANDOM_SIZE);
124     out_uint16(s, 0);
125     out_uint16_le(s, (SEC_MODULUS_SIZE + SEC_PADDING_SIZE));
126     out_uint8p(s, rsa_data, SEC_MODULUS_SIZE);
127     out_uint8s(s, SEC_PADDING_SIZE);
128    
129 matthewc 365 out_uint16_le(s, LICENCE_TAG_USER);
130     out_uint16_le(s, userlen);
131 matty 10 out_uint8p(s, user, userlen);
132    
133 matthewc 365 out_uint16_le(s, LICENCE_TAG_HOST);
134     out_uint16_le(s, hostlen);
135 matty 10 out_uint8p(s, host, hostlen);
136    
137     s_mark_end(s);
138     sec_send(s, sec_flags);
139     }
140    
141     /* Process a licence demand packet */
142 matty 25 static void
143     licence_process_demand(STREAM s)
144 matty 10 {
145     uint8 null_data[SEC_MODULUS_SIZE];
146 matthewc 190 uint8 *server_random;
147     uint8 signature[LICENCE_SIGNATURE_SIZE];
148 matthewc 39 uint8 hwid[LICENCE_HWID_SIZE];
149     uint8 *licence_data;
150     int licence_size;
151     RC4_KEY crypt_key;
152 matty 10
153     /* Retrieve the server random from the incoming packet */
154     in_uint8p(s, server_random, SEC_RANDOM_SIZE);
155    
156     /* We currently use null client keys. This is a bit naughty but, hey,
157     the security of licence negotiation isn't exactly paramount. */
158     memset(null_data, 0, sizeof(null_data));
159     licence_generate_keys(null_data, server_random, null_data);
160    
161 matthewc 39 licence_size = load_licence(&licence_data);
162 matthewc 367 if (licence_size > 0)
163 matthewc 39 {
164 matthewc 159 /* Generate a signature for the HWID buffer */
165     licence_generate_hwid(hwid);
166 jsorg71 380 sec_sign(signature, 16, g_licence_sign_key, 16, hwid, sizeof(hwid));
167 matthewc 159
168     /* Now encrypt the HWID */
169 jsorg71 380 RC4_set_key(&crypt_key, 16, g_licence_key);
170 matthewc 159 RC4(&crypt_key, sizeof(hwid), hwid, hwid);
171    
172     licence_present(null_data, null_data, licence_data, licence_size, hwid, signature);
173     xfree(licence_data);
174 matthewc 39 return;
175     }
176    
177 jsorg71 437 licence_send_request(null_data, null_data, g_username, hostname);
178 matty 10 }
179    
180     /* Send an authentication response packet */
181 matty 25 static void
182 astrand 64 licence_send_authresp(uint8 * token, uint8 * crypt_hwid, uint8 * signature)
183 matty 10 {
184     uint32 sec_flags = SEC_LICENCE_NEG;
185     uint16 length = 58;
186     STREAM s;
187    
188     s = sec_init(sec_flags, length + 2);
189    
190 matthewc 366 out_uint8(s, LICENCE_TAG_AUTHRESP);
191 forsberg 408 out_uint8(s, 2); /* version */
192 matty 10 out_uint16_le(s, length);
193    
194     out_uint16_le(s, 1);
195     out_uint16_le(s, LICENCE_TOKEN_SIZE);
196     out_uint8p(s, token, LICENCE_TOKEN_SIZE);
197    
198     out_uint16_le(s, 1);
199     out_uint16_le(s, LICENCE_HWID_SIZE);
200     out_uint8p(s, crypt_hwid, LICENCE_HWID_SIZE);
201    
202     out_uint8p(s, signature, LICENCE_SIGNATURE_SIZE);
203    
204     s_mark_end(s);
205     sec_send(s, sec_flags);
206     }
207    
208     /* Parse an authentication request packet */
209 matty 25 static BOOL
210 astrand 64 licence_parse_authreq(STREAM s, uint8 ** token, uint8 ** signature)
211 matty 10 {
212     uint16 tokenlen;
213    
214 matty 24 in_uint8s(s, 6); /* unknown: f8 3d 15 00 04 f6 */
215 matty 10
216     in_uint16_le(s, tokenlen);
217     if (tokenlen != LICENCE_TOKEN_SIZE)
218     {
219 matty 30 error("token len %d\n", tokenlen);
220 matty 10 return False;
221     }
222    
223     in_uint8p(s, *token, tokenlen);
224     in_uint8p(s, *signature, LICENCE_SIGNATURE_SIZE);
225    
226     return s_check_end(s);
227     }
228    
229     /* Process an authentication request packet */
230 matty 25 static void
231     licence_process_authreq(STREAM s)
232 matty 10 {
233     uint8 *in_token, *in_sig;
234 astrand 82 uint8 out_token[LICENCE_TOKEN_SIZE], decrypt_token[LICENCE_TOKEN_SIZE];
235 matty 10 uint8 hwid[LICENCE_HWID_SIZE], crypt_hwid[LICENCE_HWID_SIZE];
236     uint8 sealed_buffer[LICENCE_TOKEN_SIZE + LICENCE_HWID_SIZE];
237     uint8 out_sig[LICENCE_SIGNATURE_SIZE];
238     RC4_KEY crypt_key;
239    
240     /* Parse incoming packet and save the encrypted token */
241     licence_parse_authreq(s, &in_token, &in_sig);
242     memcpy(out_token, in_token, LICENCE_TOKEN_SIZE);
243    
244     /* Decrypt the token. It should read TEST in Unicode. */
245 jsorg71 380 RC4_set_key(&crypt_key, 16, g_licence_key);
246 matty 10 RC4(&crypt_key, LICENCE_TOKEN_SIZE, in_token, decrypt_token);
247    
248     /* Generate a signature for a buffer of token and HWID */
249 matthewc 39 licence_generate_hwid(hwid);
250 matty 10 memcpy(sealed_buffer, decrypt_token, LICENCE_TOKEN_SIZE);
251     memcpy(sealed_buffer + LICENCE_TOKEN_SIZE, hwid, LICENCE_HWID_SIZE);
252 jsorg71 380 sec_sign(out_sig, 16, g_licence_sign_key, 16, sealed_buffer, sizeof(sealed_buffer));
253 matty 10
254     /* Now encrypt the HWID */
255 jsorg71 380 RC4_set_key(&crypt_key, 16, g_licence_key);
256 matty 10 RC4(&crypt_key, LICENCE_HWID_SIZE, hwid, crypt_hwid);
257    
258     licence_send_authresp(out_token, crypt_hwid, out_sig);
259     }
260    
261     /* Process an licence issue packet */
262 matty 25 static void
263     licence_process_issue(STREAM s)
264 matty 10 {
265     RC4_KEY crypt_key;
266     uint32 length;
267     uint16 check;
268 matthewc 367 int i;
269 matty 10
270 matty 24 in_uint8s(s, 2); /* 3d 45 - unknown */
271 matty 10 in_uint16_le(s, length);
272     if (!s_check_rem(s, length))
273     return;
274    
275 jsorg71 380 RC4_set_key(&crypt_key, 16, g_licence_key);
276 matty 10 RC4(&crypt_key, length, s->p, s->p);
277    
278     in_uint16(s, check);
279     if (check != 0)
280     return;
281    
282 jsorg71 380 g_licence_issued = True;
283 matthewc 367
284     in_uint8s(s, 2); /* pad */
285    
286     /* advance to fourth string */
287     length = 0;
288     for (i = 0; i < 4; i++)
289     {
290     in_uint8s(s, length);
291     in_uint32_le(s, length);
292     if (!s_check_rem(s, length))
293     return;
294     }
295    
296 jsorg71 380 g_licence_issued = True;
297 matthewc 367 save_licence(s->p, length);
298 matty 10 }
299    
300     /* Process a licence packet */
301 matty 25 void
302     licence_process(STREAM s)
303 matty 10 {
304 matthewc 364 uint8 tag;
305 matty 10
306 matthewc 364 in_uint8(s, tag);
307     in_uint8s(s, 3); /* version, length */
308 matty 10
309     switch (tag)
310     {
311     case LICENCE_TAG_DEMAND:
312     licence_process_demand(s);
313     break;
314    
315     case LICENCE_TAG_AUTHREQ:
316     licence_process_authreq(s);
317     break;
318    
319     case LICENCE_TAG_ISSUE:
320     licence_process_issue(s);
321     break;
322    
323 matthewc 39 case LICENCE_TAG_REISSUE:
324 matty 10 case LICENCE_TAG_RESULT:
325     break;
326    
327     default:
328 matty 30 unimpl("licence tag 0x%x\n", tag);
329 matty 10 }
330     }

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