| 1 |
/* |
| 2 |
rdesktop: A Remote Desktop Protocol client. |
| 3 |
Protocol services - RDP encryption and licensing |
| 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 |
#include "crypto/md5.h" |
| 24 |
#include "crypto/sha.h" |
| 25 |
#include "crypto/arith.h" |
| 26 |
|
| 27 |
extern char hostname[16]; |
| 28 |
extern int width; |
| 29 |
extern int height; |
| 30 |
extern int keylayout; |
| 31 |
|
| 32 |
static int rc4_key_len; |
| 33 |
static RC4_KEY rc4_decrypt_key; |
| 34 |
static RC4_KEY rc4_encrypt_key; |
| 35 |
|
| 36 |
static uint8 sec_sign_key[8]; |
| 37 |
static uint8 sec_decrypt_key[16]; |
| 38 |
static uint8 sec_encrypt_key[16]; |
| 39 |
static uint8 sec_decrypt_update_key[8]; |
| 40 |
static uint8 sec_encrypt_update_key[8]; |
| 41 |
static uint8 sec_crypted_random[64]; |
| 42 |
|
| 43 |
/* |
| 44 |
* General purpose 48-byte transformation, using two 32-byte salts (generally, |
| 45 |
* a client and server salt) and a global salt value used for padding. |
| 46 |
* Both SHA1 and MD5 algorithms are used. |
| 47 |
*/ |
| 48 |
void sec_hash_48(uint8 *out, uint8 *in, uint8 *salt1, uint8 *salt2, |
| 49 |
uint8 salt) |
| 50 |
{ |
| 51 |
uint8 shasig[20]; |
| 52 |
uint8 pad[4]; |
| 53 |
SHA_CTX sha; |
| 54 |
MD5_CTX md5; |
| 55 |
int i; |
| 56 |
|
| 57 |
for (i = 0; i < 3; i++) |
| 58 |
{ |
| 59 |
memset(pad, salt + i, i + 1); |
| 60 |
|
| 61 |
SHA1_Init(&sha); |
| 62 |
SHA1_Update(&sha, pad, i + 1); |
| 63 |
SHA1_Update(&sha, in, 48); |
| 64 |
SHA1_Update(&sha, salt1, 32); |
| 65 |
SHA1_Update(&sha, salt2, 32); |
| 66 |
SHA1_Final(shasig, &sha); |
| 67 |
|
| 68 |
MD5_Init(&md5); |
| 69 |
MD5_Update(&md5, in, 48); |
| 70 |
MD5_Update(&md5, shasig, 20); |
| 71 |
MD5_Final(&out[i * 16], &md5); |
| 72 |
} |
| 73 |
} |
| 74 |
|
| 75 |
/* |
| 76 |
* Weaker 16-byte transformation, also using two 32-byte salts, but |
| 77 |
* only using a single round of MD5. |
| 78 |
*/ |
| 79 |
void sec_hash_16(uint8 *out, uint8 *in, uint8 *salt1, uint8 *salt2) |
| 80 |
{ |
| 81 |
MD5_CTX md5; |
| 82 |
|
| 83 |
MD5_Init(&md5); |
| 84 |
MD5_Update(&md5, in, 16); |
| 85 |
MD5_Update(&md5, salt1, 32); |
| 86 |
MD5_Update(&md5, salt2, 32); |
| 87 |
MD5_Final(out, &md5); |
| 88 |
} |
| 89 |
|
| 90 |
/* Reduce key entropy from 64 to 40 bits */ |
| 91 |
static void sec_make_40bit(uint8 *key) |
| 92 |
{ |
| 93 |
key[0] = 0xd1; |
| 94 |
key[1] = 0x26; |
| 95 |
key[2] = 0x9e; |
| 96 |
} |
| 97 |
|
| 98 |
/* Generate a session key and RC4 keys, given client and server randoms */ |
| 99 |
static void sec_generate_keys(uint8 *client_key, uint8 *server_key, |
| 100 |
int rc4_key_size) |
| 101 |
{ |
| 102 |
uint8 session_key[48]; |
| 103 |
uint8 temp_hash[48]; |
| 104 |
uint8 input[48]; |
| 105 |
|
| 106 |
/* Construct input data to hash */ |
| 107 |
memcpy(input, client_key, 24); |
| 108 |
memcpy(input + 24, server_key, 24); |
| 109 |
|
| 110 |
/* Generate session key - two rounds of sec_hash_48 */ |
| 111 |
sec_hash_48(temp_hash, input, client_key, server_key, 65); |
| 112 |
sec_hash_48(session_key, temp_hash, client_key, server_key, 88); |
| 113 |
|
| 114 |
/* Store first 8 bytes of session key, for generating signatures */ |
| 115 |
memcpy(sec_sign_key, session_key, 8); |
| 116 |
|
| 117 |
/* Generate RC4 keys */ |
| 118 |
sec_hash_16(sec_decrypt_key, &session_key[16], client_key, |
| 119 |
server_key); |
| 120 |
sec_hash_16(sec_encrypt_key, &session_key[32], client_key, |
| 121 |
server_key); |
| 122 |
|
| 123 |
if (rc4_key_size == 1) |
| 124 |
{ |
| 125 |
DEBUG("40-bit encryption enabled\n"); |
| 126 |
sec_make_40bit(sec_sign_key); |
| 127 |
sec_make_40bit(sec_decrypt_key); |
| 128 |
sec_make_40bit(sec_encrypt_key); |
| 129 |
rc4_key_len = 8; |
| 130 |
} |
| 131 |
else |
| 132 |
{ |
| 133 |
DEBUG("128-bit encryption enabled\n"); |
| 134 |
rc4_key_len = 16; |
| 135 |
} |
| 136 |
|
| 137 |
/* Store first 8 bytes of RC4 keys as update keys */ |
| 138 |
memcpy(sec_decrypt_update_key, sec_decrypt_key, 8); |
| 139 |
memcpy(sec_encrypt_update_key, sec_encrypt_key, 8); |
| 140 |
|
| 141 |
/* Initialise RC4 state arrays */ |
| 142 |
RC4_set_key(&rc4_decrypt_key, rc4_key_len, sec_decrypt_key); |
| 143 |
RC4_set_key(&rc4_encrypt_key, rc4_key_len, sec_encrypt_key); |
| 144 |
} |
| 145 |
|
| 146 |
static uint8 pad_54[40] = { |
| 147 |
54, 54, 54, 54, 54, 54, 54, 54, 54, 54, 54, 54, 54, 54, 54, 54, 54, |
| 148 |
54, 54, 54, |
| 149 |
54, 54, 54, 54, 54, 54, 54, 54, 54, 54, 54, 54, 54, 54, 54, 54, 54, |
| 150 |
54, 54, 54 |
| 151 |
}; |
| 152 |
|
| 153 |
static uint8 pad_92[48] = { |
| 154 |
92, 92, 92, 92, 92, 92, 92, 92, 92, 92, 92, 92, 92, 92, 92, 92, 92, |
| 155 |
92, 92, 92, 92, 92, 92, 92, |
| 156 |
92, 92, 92, 92, 92, 92, 92, 92, 92, 92, 92, 92, 92, 92, 92, 92, 92, |
| 157 |
92, 92, 92, 92, 92, 92, 92 |
| 158 |
}; |
| 159 |
|
| 160 |
/* Output a uint32 into a buffer (little-endian) */ |
| 161 |
void buf_out_uint32(uint8 *buffer, uint32 value) |
| 162 |
{ |
| 163 |
buffer[0] = (value) & 0xff; |
| 164 |
buffer[1] = (value >> 8) & 0xff; |
| 165 |
buffer[2] = (value >> 16) & 0xff; |
| 166 |
buffer[3] = (value >> 24) & 0xff; |
| 167 |
} |
| 168 |
|
| 169 |
/* Generate a signature hash, using a combination of SHA1 and MD5 */ |
| 170 |
void sec_sign(uint8 *signature, uint8 *session_key, int length, |
| 171 |
uint8 *data, int datalen) |
| 172 |
{ |
| 173 |
uint8 shasig[20]; |
| 174 |
uint8 md5sig[16]; |
| 175 |
uint8 lenhdr[4]; |
| 176 |
SHA_CTX sha; |
| 177 |
MD5_CTX md5; |
| 178 |
|
| 179 |
buf_out_uint32(lenhdr, datalen); |
| 180 |
|
| 181 |
SHA1_Init(&sha); |
| 182 |
SHA1_Update(&sha, session_key, length); |
| 183 |
SHA1_Update(&sha, pad_54, 40); |
| 184 |
SHA1_Update(&sha, lenhdr, 4); |
| 185 |
SHA1_Update(&sha, data, datalen); |
| 186 |
SHA1_Final(shasig, &sha); |
| 187 |
|
| 188 |
MD5_Init(&md5); |
| 189 |
MD5_Update(&md5, session_key, length); |
| 190 |
MD5_Update(&md5, pad_92, 48); |
| 191 |
MD5_Update(&md5, shasig, 20); |
| 192 |
MD5_Final(md5sig, &md5); |
| 193 |
|
| 194 |
memcpy(signature, md5sig, length); |
| 195 |
} |
| 196 |
|
| 197 |
/* Update an encryption key - similar to the signing process */ |
| 198 |
static void sec_update(uint8 *key, uint8 *update_key) |
| 199 |
{ |
| 200 |
uint8 shasig[20]; |
| 201 |
SHA_CTX sha; |
| 202 |
MD5_CTX md5; |
| 203 |
RC4_KEY update; |
| 204 |
|
| 205 |
SHA1_Init(&sha); |
| 206 |
SHA1_Update(&sha, update_key, 8); |
| 207 |
SHA1_Update(&sha, pad_54, 40); |
| 208 |
SHA1_Update(&sha, key, 8); |
| 209 |
SHA1_Final(shasig, &sha); |
| 210 |
|
| 211 |
MD5_Init(&md5); |
| 212 |
MD5_Update(&md5, update_key, 8); |
| 213 |
MD5_Update(&md5, pad_92, 48); |
| 214 |
MD5_Update(&md5, shasig, 20); |
| 215 |
MD5_Final(key, &md5); |
| 216 |
|
| 217 |
RC4_set_key(&update, rc4_key_len, key); |
| 218 |
RC4(&update, rc4_key_len, key, key); |
| 219 |
|
| 220 |
if (rc4_key_len == 8) |
| 221 |
sec_make_40bit(key); |
| 222 |
} |
| 223 |
|
| 224 |
/* Encrypt data using RC4 */ |
| 225 |
static void sec_encrypt(uint8 *data, int length) |
| 226 |
{ |
| 227 |
static int use_count; |
| 228 |
|
| 229 |
if (use_count == 4096) |
| 230 |
{ |
| 231 |
sec_update(sec_encrypt_key, sec_encrypt_update_key); |
| 232 |
RC4_set_key(&rc4_encrypt_key, rc4_key_len, sec_encrypt_key); |
| 233 |
use_count = 0; |
| 234 |
} |
| 235 |
|
| 236 |
RC4(&rc4_encrypt_key, length, data, data); |
| 237 |
use_count++; |
| 238 |
} |
| 239 |
|
| 240 |
/* Decrypt data using RC4 */ |
| 241 |
static void sec_decrypt(uint8 *data, int length) |
| 242 |
{ |
| 243 |
static int use_count; |
| 244 |
|
| 245 |
if (use_count == 4096) |
| 246 |
{ |
| 247 |
sec_update(sec_decrypt_key, sec_decrypt_update_key); |
| 248 |
RC4_set_key(&rc4_decrypt_key, rc4_key_len, sec_decrypt_key); |
| 249 |
use_count = 0; |
| 250 |
} |
| 251 |
|
| 252 |
RC4(&rc4_decrypt_key, length, data, data); |
| 253 |
use_count++; |
| 254 |
} |
| 255 |
|
| 256 |
/* Read in a NUMBER from a buffer */ |
| 257 |
static void sec_read_number(NUMBER * num, uint8 *buffer, int len) |
| 258 |
{ |
| 259 |
INT *data = num->n_part; |
| 260 |
int i, j; |
| 261 |
|
| 262 |
for (i = 0, j = 0; j < len; i++, j += 2) |
| 263 |
data[i] = buffer[j] | (buffer[j + 1] << 8); |
| 264 |
|
| 265 |
num->n_len = i; |
| 266 |
} |
| 267 |
|
| 268 |
/* Write a NUMBER to a buffer */ |
| 269 |
static void sec_write_number(NUMBER * num, uint8 *buffer, int len) |
| 270 |
{ |
| 271 |
INT *data = num->n_part; |
| 272 |
int i, j; |
| 273 |
|
| 274 |
for (i = 0, j = 0; j < len; i++, j += 2) |
| 275 |
{ |
| 276 |
buffer[j] = data[i] & 0xff; |
| 277 |
buffer[j + 1] = data[i] >> 8; |
| 278 |
} |
| 279 |
} |
| 280 |
|
| 281 |
/* Perform an RSA public key encryption operation */ |
| 282 |
static void sec_rsa_encrypt(uint8 *out, uint8 *in, int len, |
| 283 |
uint8 *modulus, uint8 *exponent) |
| 284 |
{ |
| 285 |
NUMBER data, key; |
| 286 |
|
| 287 |
/* Set modulus for arithmetic */ |
| 288 |
sec_read_number(&key, modulus, SEC_MODULUS_SIZE); |
| 289 |
m_init(&key, NULL); |
| 290 |
|
| 291 |
/* Exponentiate */ |
| 292 |
sec_read_number(&data, in, len); |
| 293 |
sec_read_number(&key, exponent, SEC_EXPONENT_SIZE); |
| 294 |
m_exp(&data, &key, &data); |
| 295 |
sec_write_number(&data, out, SEC_MODULUS_SIZE); |
| 296 |
} |
| 297 |
|
| 298 |
/* Initialise secure transport packet */ |
| 299 |
STREAM sec_init(uint32 flags, int maxlen) |
| 300 |
{ |
| 301 |
int hdrlen; |
| 302 |
STREAM s; |
| 303 |
|
| 304 |
hdrlen = (flags & SEC_ENCRYPT) ? 12 : 4; |
| 305 |
s = mcs_init(maxlen + hdrlen); |
| 306 |
s_push_layer(s, sec_hdr, hdrlen); |
| 307 |
|
| 308 |
return s; |
| 309 |
} |
| 310 |
|
| 311 |
/* Transmit secure transport packet */ |
| 312 |
void sec_send(STREAM s, uint32 flags) |
| 313 |
{ |
| 314 |
int datalen; |
| 315 |
|
| 316 |
s_pop_layer(s, sec_hdr); |
| 317 |
out_uint32_le(s, flags); |
| 318 |
|
| 319 |
if (flags & SEC_ENCRYPT) |
| 320 |
{ |
| 321 |
flags &= ~SEC_ENCRYPT; |
| 322 |
datalen = s->end - s->p - 8; |
| 323 |
|
| 324 |
#if RDP_DEBUG |
| 325 |
DEBUG("Sending encrypted packet:\n"); |
| 326 |
hexdump(s->p + 8, datalen); |
| 327 |
#endif |
| 328 |
|
| 329 |
sec_sign(s->p, sec_sign_key, 8, s->p + 8, datalen); |
| 330 |
sec_encrypt(s->p + 8, datalen); |
| 331 |
} |
| 332 |
|
| 333 |
mcs_send(s); |
| 334 |
} |
| 335 |
|
| 336 |
/* Transfer the client random to the server */ |
| 337 |
static void sec_establish_key() |
| 338 |
{ |
| 339 |
uint32 length = SEC_MODULUS_SIZE + SEC_PADDING_SIZE; |
| 340 |
uint32 flags = SEC_CLIENT_RANDOM; |
| 341 |
STREAM s; |
| 342 |
|
| 343 |
s = sec_init(flags, 76); |
| 344 |
|
| 345 |
out_uint32_le(s, length); |
| 346 |
out_uint8p(s, sec_crypted_random, SEC_MODULUS_SIZE); |
| 347 |
out_uint8s(s, SEC_PADDING_SIZE); |
| 348 |
|
| 349 |
s_mark_end(s); |
| 350 |
sec_send(s, flags); |
| 351 |
} |
| 352 |
|
| 353 |
/* Output connect initial data blob */ |
| 354 |
static void sec_out_mcs_data(STREAM s) |
| 355 |
{ |
| 356 |
int hostlen = 2 * strlen(hostname); |
| 357 |
|
| 358 |
out_uint16_be(s, 5); /* unknown */ |
| 359 |
out_uint16_be(s, 0x14); |
| 360 |
out_uint8(s, 0x7c); |
| 361 |
out_uint16_be(s, 1); |
| 362 |
|
| 363 |
out_uint16_be(s, (158 | 0x8000)); /* remaining length */ |
| 364 |
|
| 365 |
out_uint16_be(s, 8); /* length? */ |
| 366 |
out_uint16_be(s, 16); |
| 367 |
out_uint8(s, 0); |
| 368 |
out_uint16_le(s, 0xc001); |
| 369 |
out_uint8(s, 0); |
| 370 |
|
| 371 |
out_uint32_le(s, 0x61637544); /* "Duca" ?! */ |
| 372 |
out_uint16_be(s, (144 | 0x8000)); /* remaining length */ |
| 373 |
|
| 374 |
/* Client information */ |
| 375 |
out_uint16_le(s, SEC_TAG_CLI_INFO); |
| 376 |
out_uint16_le(s, 136); /* length */ |
| 377 |
out_uint16_le(s, 1); |
| 378 |
out_uint16_le(s, 8); |
| 379 |
out_uint16_le(s, width); |
| 380 |
out_uint16_le(s, height); |
| 381 |
out_uint16_le(s, 0xca01); |
| 382 |
out_uint16_le(s, 0xaa03); |
| 383 |
out_uint32_le(s, keylayout); |
| 384 |
out_uint32_le(s, 419); /* client build? we are 419 compatible :-) */ |
| 385 |
|
| 386 |
/* Unicode name of client, padded to 32 bytes */ |
| 387 |
rdp_out_unistr(s, hostname, hostlen); |
| 388 |
out_uint8s(s, 30 - hostlen); |
| 389 |
|
| 390 |
out_uint32_le(s, 4); |
| 391 |
out_uint32(s, 0); |
| 392 |
out_uint32_le(s, 12); |
| 393 |
out_uint8s(s, 64); /* reserved? 4 + 12 doublewords */ |
| 394 |
|
| 395 |
out_uint16(s, 0xca01); |
| 396 |
out_uint16(s, 0); |
| 397 |
|
| 398 |
/* Client encryption settings */ |
| 399 |
out_uint16_le(s, SEC_TAG_CLI_CRYPT); |
| 400 |
out_uint16(s, 8); /* length */ |
| 401 |
out_uint32_le(s, 1); /* encryption enabled */ |
| 402 |
s_mark_end(s); |
| 403 |
} |
| 404 |
|
| 405 |
/* Parse a public key structure */ |
| 406 |
static BOOL sec_parse_public_key(STREAM s, uint8 **modulus, uint8 **exponent) |
| 407 |
{ |
| 408 |
uint32 magic, modulus_len; |
| 409 |
|
| 410 |
in_uint32_le(s, magic); |
| 411 |
if (magic != SEC_RSA_MAGIC) |
| 412 |
{ |
| 413 |
ERROR("RSA magic 0x%x\n", magic); |
| 414 |
return False; |
| 415 |
} |
| 416 |
|
| 417 |
in_uint32_le(s, modulus_len); |
| 418 |
if (modulus_len != SEC_MODULUS_SIZE + SEC_PADDING_SIZE) |
| 419 |
{ |
| 420 |
ERROR("modulus len 0x%x\n", modulus_len); |
| 421 |
return False; |
| 422 |
} |
| 423 |
|
| 424 |
in_uint8s(s, 8); /* modulus_bits, unknown */ |
| 425 |
in_uint8p(s, *exponent, SEC_EXPONENT_SIZE); |
| 426 |
in_uint8p(s, *modulus, SEC_MODULUS_SIZE); |
| 427 |
in_uint8s(s, SEC_PADDING_SIZE); |
| 428 |
|
| 429 |
return s_check(s); |
| 430 |
} |
| 431 |
|
| 432 |
/* Parse a crypto information structure */ |
| 433 |
static BOOL sec_parse_crypt_info(STREAM s, uint32 *rc4_key_size, |
| 434 |
uint8 **server_random, uint8 **modulus, |
| 435 |
uint8 **exponent) |
| 436 |
{ |
| 437 |
uint32 crypt_level, random_len, rsa_info_len; |
| 438 |
uint16 tag, length; |
| 439 |
uint8 *next_tag, *end; |
| 440 |
|
| 441 |
in_uint32_le(s, *rc4_key_size); /* 1 = 40-bit, 2 = 128-bit */ |
| 442 |
in_uint32_le(s, crypt_level); /* 1 = low, 2 = medium, 3 = high */ |
| 443 |
in_uint32_le(s, random_len); |
| 444 |
in_uint32_le(s, rsa_info_len); |
| 445 |
|
| 446 |
if (random_len != SEC_RANDOM_SIZE) |
| 447 |
{ |
| 448 |
ERROR("random len %d\n", random_len); |
| 449 |
return False; |
| 450 |
} |
| 451 |
|
| 452 |
in_uint8p(s, *server_random, random_len); |
| 453 |
|
| 454 |
/* RSA info */ |
| 455 |
end = s->p + rsa_info_len; |
| 456 |
if (end > s->end) |
| 457 |
return False; |
| 458 |
|
| 459 |
in_uint8s(s, 12); /* unknown */ |
| 460 |
|
| 461 |
while (s->p < end) |
| 462 |
{ |
| 463 |
in_uint16_le(s, tag); |
| 464 |
in_uint16_le(s, length); |
| 465 |
|
| 466 |
next_tag = s->p + length; |
| 467 |
|
| 468 |
switch (tag) |
| 469 |
{ |
| 470 |
case SEC_TAG_PUBKEY: |
| 471 |
if (!sec_parse_public_key |
| 472 |
(s, modulus, exponent)) |
| 473 |
return False; |
| 474 |
|
| 475 |
break; |
| 476 |
|
| 477 |
case SEC_TAG_KEYSIG: |
| 478 |
/* Is this a Microsoft key that we just got? */ |
| 479 |
/* Care factor: zero! */ |
| 480 |
break; |
| 481 |
|
| 482 |
default: |
| 483 |
NOTIMP("crypt tag 0x%x\n", tag); |
| 484 |
} |
| 485 |
|
| 486 |
s->p = next_tag; |
| 487 |
} |
| 488 |
|
| 489 |
return s_check_end(s); |
| 490 |
} |
| 491 |
|
| 492 |
/* Process crypto information blob */ |
| 493 |
static void sec_process_crypt_info(STREAM s) |
| 494 |
{ |
| 495 |
uint8 *server_random, *modulus, *exponent; |
| 496 |
uint8 client_random[SEC_RANDOM_SIZE]; |
| 497 |
uint32 rc4_key_size; |
| 498 |
|
| 499 |
if (!sec_parse_crypt_info(s, &rc4_key_size, &server_random, |
| 500 |
&modulus, &exponent)) |
| 501 |
return; |
| 502 |
|
| 503 |
/* Generate a client random, and hence determine encryption keys */ |
| 504 |
generate_random(client_random); |
| 505 |
sec_rsa_encrypt(sec_crypted_random, client_random, |
| 506 |
SEC_RANDOM_SIZE, modulus, exponent); |
| 507 |
sec_generate_keys(client_random, server_random, rc4_key_size); |
| 508 |
} |
| 509 |
|
| 510 |
/* Process connect response data blob */ |
| 511 |
static void sec_process_mcs_data(STREAM s) |
| 512 |
{ |
| 513 |
uint16 tag, length; |
| 514 |
uint8 *next_tag; |
| 515 |
|
| 516 |
in_uint8s(s, 23); /* header */ |
| 517 |
|
| 518 |
while (s->p < s->end) |
| 519 |
{ |
| 520 |
in_uint16_le(s, tag); |
| 521 |
in_uint16_le(s, length); |
| 522 |
|
| 523 |
if (length <= 4) |
| 524 |
return; |
| 525 |
|
| 526 |
next_tag = s->p + length - 4; |
| 527 |
|
| 528 |
switch (tag) |
| 529 |
{ |
| 530 |
case SEC_TAG_SRV_INFO: |
| 531 |
case SEC_TAG_SRV_3: |
| 532 |
break; |
| 533 |
|
| 534 |
case SEC_TAG_SRV_CRYPT: |
| 535 |
sec_process_crypt_info(s); |
| 536 |
break; |
| 537 |
|
| 538 |
default: |
| 539 |
NOTIMP("response tag 0x%x\n", tag); |
| 540 |
} |
| 541 |
|
| 542 |
s->p = next_tag; |
| 543 |
} |
| 544 |
} |
| 545 |
|
| 546 |
/* Receive secure transport packet */ |
| 547 |
STREAM sec_recv() |
| 548 |
{ |
| 549 |
uint32 sec_flags; |
| 550 |
STREAM s; |
| 551 |
|
| 552 |
while ((s = mcs_recv()) != NULL) |
| 553 |
{ |
| 554 |
in_uint32_le(s, sec_flags); |
| 555 |
|
| 556 |
if (sec_flags & SEC_LICENCE_NEG) |
| 557 |
{ |
| 558 |
licence_process(s); |
| 559 |
continue; |
| 560 |
} |
| 561 |
|
| 562 |
if (sec_flags & SEC_ENCRYPT) |
| 563 |
{ |
| 564 |
in_uint8s(s, 8); /* signature */ |
| 565 |
sec_decrypt(s->p, s->end - s->p); |
| 566 |
} |
| 567 |
|
| 568 |
return s; |
| 569 |
} |
| 570 |
|
| 571 |
return NULL; |
| 572 |
} |
| 573 |
|
| 574 |
/* Establish a secure connection */ |
| 575 |
BOOL sec_connect(char *server) |
| 576 |
{ |
| 577 |
struct stream mcs_data; |
| 578 |
|
| 579 |
/* We exchange some RDP data during the MCS-Connect */ |
| 580 |
mcs_data.size = 512; |
| 581 |
mcs_data.p = mcs_data.data = xmalloc(mcs_data.size); |
| 582 |
sec_out_mcs_data(&mcs_data); |
| 583 |
|
| 584 |
if (!mcs_connect(server, &mcs_data)) |
| 585 |
return False; |
| 586 |
|
| 587 |
sec_process_mcs_data(&mcs_data); |
| 588 |
sec_establish_key(); |
| 589 |
return True; |
| 590 |
} |
| 591 |
|
| 592 |
/* Disconnect a connection */ |
| 593 |
void sec_disconnect() |
| 594 |
{ |
| 595 |
mcs_disconnect(); |
| 596 |
} |
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