| 1 |
/* |
| 2 |
rdesktop: A Remote Desktop Protocol client. |
| 3 |
RDP licensing negotiation |
| 4 |
Copyright (C) Matthew Chapman 1999-2002 |
| 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 <sys/types.h> |
| 22 |
#include <sys/stat.h> |
| 23 |
#include <unistd.h> |
| 24 |
#include <fcntl.h> |
| 25 |
#include <errno.h> |
| 26 |
#include "rdesktop.h" |
| 27 |
|
| 28 |
#ifdef WITH_OPENSSL |
| 29 |
#include <openssl/rc4.h> |
| 30 |
#else |
| 31 |
#include "crypto/rc4.h" |
| 32 |
#endif |
| 33 |
|
| 34 |
extern char username[16]; |
| 35 |
extern char hostname[16]; |
| 36 |
|
| 37 |
static uint8 licence_key[16]; |
| 38 |
static uint8 licence_sign_key[16]; |
| 39 |
|
| 40 |
BOOL licence_issued = False; |
| 41 |
|
| 42 |
|
| 43 |
int |
| 44 |
load_licence(unsigned char **data) |
| 45 |
{ |
| 46 |
char *path; |
| 47 |
char *home; |
| 48 |
struct stat st; |
| 49 |
int fd; |
| 50 |
|
| 51 |
home = getenv("HOME"); |
| 52 |
if (home == NULL) |
| 53 |
return -1; |
| 54 |
|
| 55 |
path = xmalloc(strlen(home) + strlen(hostname) + 20); |
| 56 |
sprintf(path, "%s/.rdesktop/licence.%s", home, hostname); |
| 57 |
|
| 58 |
fd = open(path, O_RDONLY); |
| 59 |
if (fd == -1) |
| 60 |
return -1; |
| 61 |
|
| 62 |
if (fstat(fd, &st)) |
| 63 |
return -1; |
| 64 |
|
| 65 |
*data = xmalloc(st.st_size); |
| 66 |
return read(fd, *data, st.st_size); |
| 67 |
} |
| 68 |
|
| 69 |
void |
| 70 |
save_licence(unsigned char *data, int length) |
| 71 |
{ |
| 72 |
char *fpath; /* file path for licence */ |
| 73 |
char *fname, *fnamewrk; /* file name for licence .inkl path. */ |
| 74 |
char *home; |
| 75 |
uint32 y; |
| 76 |
struct flock fnfl; |
| 77 |
int fnfd, fnwrkfd, i, wlen; |
| 78 |
struct stream s, *s_ptr; |
| 79 |
uint32 len; |
| 80 |
|
| 81 |
/* Construct a stream, so that we can use macros to extract the |
| 82 |
* licence. |
| 83 |
*/ |
| 84 |
s_ptr = &s; |
| 85 |
s_ptr->p = data; |
| 86 |
/* Skip first two bytes */ |
| 87 |
in_uint16(s_ptr, len); |
| 88 |
|
| 89 |
/* Skip three strings */ |
| 90 |
for (i = 0; i < 3; i++) |
| 91 |
{ |
| 92 |
in_uint32(s_ptr, len); |
| 93 |
s_ptr->p += len; |
| 94 |
/* Make sure that we won't be past the end of data after |
| 95 |
* reading the next length value |
| 96 |
*/ |
| 97 |
if ((s_ptr->p) + 4 > data + length) |
| 98 |
{ |
| 99 |
printf("Error in parsing licence key.\n"); |
| 100 |
printf("Strings %d end value %x > supplied length (%x)\n", i, |
| 101 |
(unsigned int) s_ptr->p, (unsigned int) data + length); |
| 102 |
return; |
| 103 |
} |
| 104 |
} |
| 105 |
in_uint32(s_ptr, len); |
| 106 |
if (s_ptr->p + len > data + length) |
| 107 |
{ |
| 108 |
printf("Error in parsing licence key.\n"); |
| 109 |
printf("End of licence %x > supplied length (%x)\n", |
| 110 |
(unsigned int) s_ptr->p + len, (unsigned int) data + length); |
| 111 |
return; |
| 112 |
} |
| 113 |
|
| 114 |
home = getenv("HOME"); |
| 115 |
if (home == NULL) |
| 116 |
return; |
| 117 |
|
| 118 |
/* set and create the directory -- if it doesn't exist. */ |
| 119 |
fpath = xmalloc(strlen(home) + 11); |
| 120 |
STRNCPY(fpath, home, strlen(home) + 1); |
| 121 |
|
| 122 |
sprintf(fpath, "%s/.rdesktop", fpath); |
| 123 |
if (mkdir(fpath, 0700) == -1 && errno != EEXIST) |
| 124 |
{ |
| 125 |
perror("mkdir"); |
| 126 |
exit(1); |
| 127 |
} |
| 128 |
|
| 129 |
/* set the real licence filename, and put a write lock on it. */ |
| 130 |
fname = xmalloc(strlen(fpath) + strlen(hostname) + 10); |
| 131 |
sprintf(fname, "%s/licence.%s", fpath, hostname); |
| 132 |
fnfd = open(fname, O_RDONLY); |
| 133 |
if (fnfd != -1) |
| 134 |
{ |
| 135 |
fnfl.l_type = F_WRLCK; |
| 136 |
fnfl.l_whence = SEEK_SET; |
| 137 |
fnfl.l_start = 0; |
| 138 |
fnfl.l_len = 1; |
| 139 |
fcntl(fnfd, F_SETLK, &fnfl); |
| 140 |
} |
| 141 |
|
| 142 |
/* create a temporary licence file */ |
| 143 |
fnamewrk = xmalloc(strlen(fname) + 12); |
| 144 |
for (y = 0;; y++) |
| 145 |
{ |
| 146 |
sprintf(fnamewrk, "%s.%lu", fname, (long unsigned int) y); |
| 147 |
fnwrkfd = open(fnamewrk, O_WRONLY | O_CREAT | O_EXCL, 0600); |
| 148 |
if (fnwrkfd == -1) |
| 149 |
{ |
| 150 |
if (errno == EINTR || errno == EEXIST) |
| 151 |
continue; |
| 152 |
perror("create"); |
| 153 |
exit(1); |
| 154 |
} |
| 155 |
break; |
| 156 |
} |
| 157 |
/* write to the licence file */ |
| 158 |
for (y = 0; y < len;) |
| 159 |
{ |
| 160 |
do |
| 161 |
{ |
| 162 |
wlen = write(fnwrkfd, s_ptr->p + y, len - y); |
| 163 |
} |
| 164 |
while (wlen == -1 && errno == EINTR); |
| 165 |
if (wlen < 1) |
| 166 |
{ |
| 167 |
perror("write"); |
| 168 |
unlink(fnamewrk); |
| 169 |
exit(1); |
| 170 |
} |
| 171 |
y += wlen; |
| 172 |
} |
| 173 |
|
| 174 |
/* close the file and rename it to fname */ |
| 175 |
if (close(fnwrkfd) == -1) |
| 176 |
{ |
| 177 |
perror("close"); |
| 178 |
unlink(fnamewrk); |
| 179 |
exit(1); |
| 180 |
} |
| 181 |
if (rename(fnamewrk, fname) == -1) |
| 182 |
{ |
| 183 |
perror("rename"); |
| 184 |
unlink(fnamewrk); |
| 185 |
exit(1); |
| 186 |
} |
| 187 |
/* close the file lock on fname */ |
| 188 |
if (fnfd != -1) |
| 189 |
{ |
| 190 |
fnfl.l_type = F_UNLCK; |
| 191 |
fnfl.l_whence = SEEK_SET; |
| 192 |
fnfl.l_start = 0; |
| 193 |
fnfl.l_len = 1; |
| 194 |
fcntl(fnfd, F_SETLK, &fnfl); |
| 195 |
close(fnfd); |
| 196 |
} |
| 197 |
|
| 198 |
} |
| 199 |
|
| 200 |
/* Generate a session key and RC4 keys, given client and server randoms */ |
| 201 |
static void |
| 202 |
licence_generate_keys(uint8 * client_key, uint8 * server_key, uint8 * client_rsa) |
| 203 |
{ |
| 204 |
uint8 session_key[48]; |
| 205 |
uint8 temp_hash[48]; |
| 206 |
|
| 207 |
/* Generate session key - two rounds of sec_hash_48 */ |
| 208 |
sec_hash_48(temp_hash, client_rsa, client_key, server_key, 65); |
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sec_hash_48(session_key, temp_hash, server_key, client_key, 65); |
| 210 |
|
| 211 |
/* Store first 16 bytes of session key, for generating signatures */ |
| 212 |
memcpy(licence_sign_key, session_key, 16); |
| 213 |
|
| 214 |
/* Generate RC4 key */ |
| 215 |
sec_hash_16(licence_key, &session_key[16], client_key, server_key); |
| 216 |
} |
| 217 |
|
| 218 |
static void |
| 219 |
licence_generate_hwid(uint8 * hwid) |
| 220 |
{ |
| 221 |
buf_out_uint32(hwid, 2); |
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strncpy((char *) (hwid + 4), hostname, LICENCE_HWID_SIZE - 4); |
| 223 |
} |
| 224 |
|
| 225 |
/* Present an existing licence to the server */ |
| 226 |
static void |
| 227 |
licence_present(uint8 * client_random, uint8 * rsa_data, |
| 228 |
uint8 * licence_data, int licence_size, uint8 * hwid, uint8 * signature) |
| 229 |
{ |
| 230 |
uint32 sec_flags = SEC_LICENCE_NEG; |
| 231 |
uint16 length = |
| 232 |
16 + SEC_RANDOM_SIZE + SEC_MODULUS_SIZE + SEC_PADDING_SIZE + |
| 233 |
licence_size + LICENCE_HWID_SIZE + LICENCE_SIGNATURE_SIZE; |
| 234 |
STREAM s; |
| 235 |
|
| 236 |
s = sec_init(sec_flags, length + 4); |
| 237 |
|
| 238 |
out_uint16_le(s, LICENCE_TAG_PRESENT); |
| 239 |
out_uint16_le(s, length); |
| 240 |
|
| 241 |
out_uint32_le(s, 1); |
| 242 |
out_uint16(s, 0); |
| 243 |
out_uint16_le(s, 0x0201); |
| 244 |
|
| 245 |
out_uint8p(s, client_random, SEC_RANDOM_SIZE); |
| 246 |
out_uint16(s, 0); |
| 247 |
out_uint16_le(s, (SEC_MODULUS_SIZE + SEC_PADDING_SIZE)); |
| 248 |
out_uint8p(s, rsa_data, SEC_MODULUS_SIZE); |
| 249 |
out_uint8s(s, SEC_PADDING_SIZE); |
| 250 |
|
| 251 |
out_uint16_le(s, 1); |
| 252 |
out_uint16_le(s, licence_size); |
| 253 |
out_uint8p(s, licence_data, licence_size); |
| 254 |
|
| 255 |
out_uint16_le(s, 1); |
| 256 |
out_uint16_le(s, LICENCE_HWID_SIZE); |
| 257 |
out_uint8p(s, hwid, LICENCE_HWID_SIZE); |
| 258 |
|
| 259 |
out_uint8p(s, signature, LICENCE_SIGNATURE_SIZE); |
| 260 |
|
| 261 |
s_mark_end(s); |
| 262 |
sec_send(s, sec_flags); |
| 263 |
} |
| 264 |
|
| 265 |
/* Send a licence request packet */ |
| 266 |
static void |
| 267 |
licence_send_request(uint8 * client_random, uint8 * rsa_data, char *user, char *host) |
| 268 |
{ |
| 269 |
uint32 sec_flags = SEC_LICENCE_NEG; |
| 270 |
uint16 userlen = strlen(user) + 1; |
| 271 |
uint16 hostlen = strlen(host) + 1; |
| 272 |
uint16 length = 128 + userlen + hostlen; |
| 273 |
STREAM s; |
| 274 |
|
| 275 |
s = sec_init(sec_flags, length + 2); |
| 276 |
|
| 277 |
out_uint16_le(s, LICENCE_TAG_REQUEST); |
| 278 |
out_uint16_le(s, length); |
| 279 |
|
| 280 |
out_uint32_le(s, 1); |
| 281 |
out_uint16(s, 0); |
| 282 |
out_uint16_le(s, 0xff01); |
| 283 |
|
| 284 |
out_uint8p(s, client_random, SEC_RANDOM_SIZE); |
| 285 |
out_uint16(s, 0); |
| 286 |
out_uint16_le(s, (SEC_MODULUS_SIZE + SEC_PADDING_SIZE)); |
| 287 |
out_uint8p(s, rsa_data, SEC_MODULUS_SIZE); |
| 288 |
out_uint8s(s, SEC_PADDING_SIZE); |
| 289 |
|
| 290 |
out_uint16(s, LICENCE_TAG_USER); |
| 291 |
out_uint16(s, userlen); |
| 292 |
out_uint8p(s, user, userlen); |
| 293 |
|
| 294 |
out_uint16(s, LICENCE_TAG_HOST); |
| 295 |
out_uint16(s, hostlen); |
| 296 |
out_uint8p(s, host, hostlen); |
| 297 |
|
| 298 |
s_mark_end(s); |
| 299 |
sec_send(s, sec_flags); |
| 300 |
} |
| 301 |
|
| 302 |
/* Process a licence demand packet */ |
| 303 |
static void |
| 304 |
licence_process_demand(STREAM s) |
| 305 |
{ |
| 306 |
uint8 null_data[SEC_MODULUS_SIZE]; |
| 307 |
uint8 *server_random; |
| 308 |
uint8 signature[LICENCE_SIGNATURE_SIZE]; |
| 309 |
uint8 hwid[LICENCE_HWID_SIZE]; |
| 310 |
uint8 *licence_data; |
| 311 |
int licence_size; |
| 312 |
RC4_KEY crypt_key; |
| 313 |
|
| 314 |
/* Retrieve the server random from the incoming packet */ |
| 315 |
in_uint8p(s, server_random, SEC_RANDOM_SIZE); |
| 316 |
|
| 317 |
/* We currently use null client keys. This is a bit naughty but, hey, |
| 318 |
the security of licence negotiation isn't exactly paramount. */ |
| 319 |
memset(null_data, 0, sizeof(null_data)); |
| 320 |
licence_generate_keys(null_data, server_random, null_data); |
| 321 |
|
| 322 |
licence_size = load_licence(&licence_data); |
| 323 |
if (licence_size != -1) |
| 324 |
{ |
| 325 |
/* Generate a signature for the HWID buffer */ |
| 326 |
licence_generate_hwid(hwid); |
| 327 |
sec_sign(signature, 16, licence_sign_key, 16, hwid, sizeof(hwid)); |
| 328 |
|
| 329 |
/* Now encrypt the HWID */ |
| 330 |
RC4_set_key(&crypt_key, 16, licence_key); |
| 331 |
RC4(&crypt_key, sizeof(hwid), hwid, hwid); |
| 332 |
|
| 333 |
licence_present(null_data, null_data, licence_data, licence_size, hwid, signature); |
| 334 |
xfree(licence_data); |
| 335 |
return; |
| 336 |
} |
| 337 |
|
| 338 |
licence_send_request(null_data, null_data, username, hostname); |
| 339 |
} |
| 340 |
|
| 341 |
/* Send an authentication response packet */ |
| 342 |
static void |
| 343 |
licence_send_authresp(uint8 * token, uint8 * crypt_hwid, uint8 * signature) |
| 344 |
{ |
| 345 |
uint32 sec_flags = SEC_LICENCE_NEG; |
| 346 |
uint16 length = 58; |
| 347 |
STREAM s; |
| 348 |
|
| 349 |
s = sec_init(sec_flags, length + 2); |
| 350 |
|
| 351 |
out_uint16_le(s, LICENCE_TAG_AUTHRESP); |
| 352 |
out_uint16_le(s, length); |
| 353 |
|
| 354 |
out_uint16_le(s, 1); |
| 355 |
out_uint16_le(s, LICENCE_TOKEN_SIZE); |
| 356 |
out_uint8p(s, token, LICENCE_TOKEN_SIZE); |
| 357 |
|
| 358 |
out_uint16_le(s, 1); |
| 359 |
out_uint16_le(s, LICENCE_HWID_SIZE); |
| 360 |
out_uint8p(s, crypt_hwid, LICENCE_HWID_SIZE); |
| 361 |
|
| 362 |
out_uint8p(s, signature, LICENCE_SIGNATURE_SIZE); |
| 363 |
|
| 364 |
s_mark_end(s); |
| 365 |
sec_send(s, sec_flags); |
| 366 |
} |
| 367 |
|
| 368 |
/* Parse an authentication request packet */ |
| 369 |
static BOOL |
| 370 |
licence_parse_authreq(STREAM s, uint8 ** token, uint8 ** signature) |
| 371 |
{ |
| 372 |
uint16 tokenlen; |
| 373 |
|
| 374 |
in_uint8s(s, 6); /* unknown: f8 3d 15 00 04 f6 */ |
| 375 |
|
| 376 |
in_uint16_le(s, tokenlen); |
| 377 |
if (tokenlen != LICENCE_TOKEN_SIZE) |
| 378 |
{ |
| 379 |
error("token len %d\n", tokenlen); |
| 380 |
return False; |
| 381 |
} |
| 382 |
|
| 383 |
in_uint8p(s, *token, tokenlen); |
| 384 |
in_uint8p(s, *signature, LICENCE_SIGNATURE_SIZE); |
| 385 |
|
| 386 |
return s_check_end(s); |
| 387 |
} |
| 388 |
|
| 389 |
/* Process an authentication request packet */ |
| 390 |
static void |
| 391 |
licence_process_authreq(STREAM s) |
| 392 |
{ |
| 393 |
uint8 *in_token, *in_sig; |
| 394 |
uint8 out_token[LICENCE_TOKEN_SIZE], decrypt_token[LICENCE_TOKEN_SIZE]; |
| 395 |
uint8 hwid[LICENCE_HWID_SIZE], crypt_hwid[LICENCE_HWID_SIZE]; |
| 396 |
uint8 sealed_buffer[LICENCE_TOKEN_SIZE + LICENCE_HWID_SIZE]; |
| 397 |
uint8 out_sig[LICENCE_SIGNATURE_SIZE]; |
| 398 |
RC4_KEY crypt_key; |
| 399 |
|
| 400 |
/* Parse incoming packet and save the encrypted token */ |
| 401 |
licence_parse_authreq(s, &in_token, &in_sig); |
| 402 |
memcpy(out_token, in_token, LICENCE_TOKEN_SIZE); |
| 403 |
|
| 404 |
/* Decrypt the token. It should read TEST in Unicode. */ |
| 405 |
RC4_set_key(&crypt_key, 16, licence_key); |
| 406 |
RC4(&crypt_key, LICENCE_TOKEN_SIZE, in_token, decrypt_token); |
| 407 |
|
| 408 |
/* Generate a signature for a buffer of token and HWID */ |
| 409 |
licence_generate_hwid(hwid); |
| 410 |
memcpy(sealed_buffer, decrypt_token, LICENCE_TOKEN_SIZE); |
| 411 |
memcpy(sealed_buffer + LICENCE_TOKEN_SIZE, hwid, LICENCE_HWID_SIZE); |
| 412 |
sec_sign(out_sig, 16, licence_sign_key, 16, sealed_buffer, sizeof(sealed_buffer)); |
| 413 |
|
| 414 |
/* Now encrypt the HWID */ |
| 415 |
RC4_set_key(&crypt_key, 16, licence_key); |
| 416 |
RC4(&crypt_key, LICENCE_HWID_SIZE, hwid, crypt_hwid); |
| 417 |
|
| 418 |
licence_send_authresp(out_token, crypt_hwid, out_sig); |
| 419 |
} |
| 420 |
|
| 421 |
/* Process an licence issue packet */ |
| 422 |
static void |
| 423 |
licence_process_issue(STREAM s) |
| 424 |
{ |
| 425 |
RC4_KEY crypt_key; |
| 426 |
uint32 length; |
| 427 |
uint16 check; |
| 428 |
|
| 429 |
in_uint8s(s, 2); /* 3d 45 - unknown */ |
| 430 |
in_uint16_le(s, length); |
| 431 |
if (!s_check_rem(s, length)) |
| 432 |
return; |
| 433 |
|
| 434 |
RC4_set_key(&crypt_key, 16, licence_key); |
| 435 |
RC4(&crypt_key, length, s->p, s->p); |
| 436 |
|
| 437 |
in_uint16(s, check); |
| 438 |
if (check != 0) |
| 439 |
return; |
| 440 |
|
| 441 |
licence_issued = True; |
| 442 |
save_licence(s->p, length - 2); |
| 443 |
} |
| 444 |
|
| 445 |
/* Process a licence packet */ |
| 446 |
void |
| 447 |
licence_process(STREAM s) |
| 448 |
{ |
| 449 |
uint16 tag; |
| 450 |
|
| 451 |
in_uint16_le(s, tag); |
| 452 |
in_uint8s(s, 2); /* length */ |
| 453 |
|
| 454 |
switch (tag) |
| 455 |
{ |
| 456 |
case LICENCE_TAG_DEMAND: |
| 457 |
licence_process_demand(s); |
| 458 |
break; |
| 459 |
|
| 460 |
case LICENCE_TAG_AUTHREQ: |
| 461 |
licence_process_authreq(s); |
| 462 |
break; |
| 463 |
|
| 464 |
case LICENCE_TAG_ISSUE: |
| 465 |
licence_process_issue(s); |
| 466 |
break; |
| 467 |
|
| 468 |
case LICENCE_TAG_REISSUE: |
| 469 |
break; |
| 470 |
|
| 471 |
case LICENCE_TAG_RESULT: |
| 472 |
break; |
| 473 |
|
| 474 |
default: |
| 475 |
unimpl("licence tag 0x%x\n", tag); |
| 476 |
} |
| 477 |
} |
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