| 1 | /* |
| 2 | * Network proxy abstraction in PuTTY |
| 3 | * |
| 4 | * A proxy layer, if necessary, wedges itself between the network |
| 5 | * code and the higher level backend. |
| 6 | */ |
| 7 | |
| 8 | #include <windows.h> |
| 9 | |
| 10 | #define DEFINE_PLUG_METHOD_MACROS |
| 11 | #include "putty.h" |
| 12 | #include "network.h" |
| 13 | #include "proxy.h" |
| 14 | |
| 15 | /* |
| 16 | * Call this when proxy negotiation is complete, so that this |
| 17 | * socket can begin working normally. |
| 18 | */ |
| 19 | void proxy_activate (Proxy_Socket p) |
| 20 | { |
| 21 | void *data; |
| 22 | int len; |
| 23 | |
| 24 | p->state = PROXY_STATE_ACTIVE; |
| 25 | |
| 26 | /* let's try to keep extra receive events from coming through */ |
| 27 | sk_set_frozen(p->sub_socket, 1); |
| 28 | |
| 29 | /* send buffered OOB writes */ |
| 30 | while (bufchain_size(&p->pending_oob_output_data) > 0) { |
| 31 | bufchain_prefix(&p->pending_oob_output_data, &data, &len); |
| 32 | sk_write_oob(p->sub_socket, data, len); |
| 33 | bufchain_consume(&p->pending_oob_output_data, len); |
| 34 | } |
| 35 | bufchain_clear(&p->pending_oob_output_data); |
| 36 | |
| 37 | /* send buffered normal writes */ |
| 38 | while (bufchain_size(&p->pending_output_data) > 0) { |
| 39 | bufchain_prefix(&p->pending_output_data, &data, &len); |
| 40 | sk_write(p->sub_socket, data, len); |
| 41 | bufchain_consume(&p->pending_output_data, len); |
| 42 | } |
| 43 | bufchain_clear(&p->pending_output_data); |
| 44 | |
| 45 | /* if we were asked to flush the output during |
| 46 | * the proxy negotiation process, do so now. |
| 47 | */ |
| 48 | if (p->pending_flush) sk_flush(p->sub_socket); |
| 49 | |
| 50 | /* forward buffered recv data to the backend */ |
| 51 | while (bufchain_size(&p->pending_input_data) > 0) { |
| 52 | bufchain_prefix(&p->pending_input_data, &data, &len); |
| 53 | plug_receive(p->plug, 0, data, len); |
| 54 | bufchain_consume(&p->pending_input_data, len); |
| 55 | } |
| 56 | bufchain_clear(&p->pending_input_data); |
| 57 | |
| 58 | /* now set the underlying socket to whatever freeze state they wanted */ |
| 59 | sk_set_frozen(p->sub_socket, p->freeze); |
| 60 | } |
| 61 | |
| 62 | /* basic proxy socket functions */ |
| 63 | |
| 64 | static Plug sk_proxy_plug (Socket s, Plug p) |
| 65 | { |
| 66 | Proxy_Socket ps = (Proxy_Socket) s; |
| 67 | Plug ret = ps->plug; |
| 68 | if (p) |
| 69 | ps->plug = p; |
| 70 | return ret; |
| 71 | } |
| 72 | |
| 73 | static void sk_proxy_close (Socket s) |
| 74 | { |
| 75 | Proxy_Socket ps = (Proxy_Socket) s; |
| 76 | |
| 77 | sk_close(ps->sub_socket); |
| 78 | sfree(ps); |
| 79 | } |
| 80 | |
| 81 | static int sk_proxy_write (Socket s, char *data, int len) |
| 82 | { |
| 83 | Proxy_Socket ps = (Proxy_Socket) s; |
| 84 | |
| 85 | if (ps->state != PROXY_STATE_ACTIVE) { |
| 86 | bufchain_add(&ps->pending_output_data, data, len); |
| 87 | return bufchain_size(&ps->pending_output_data); |
| 88 | } |
| 89 | return sk_write(ps->sub_socket, data, len); |
| 90 | } |
| 91 | |
| 92 | static int sk_proxy_write_oob (Socket s, char *data, int len) |
| 93 | { |
| 94 | Proxy_Socket ps = (Proxy_Socket) s; |
| 95 | |
| 96 | if (ps->state != PROXY_STATE_ACTIVE) { |
| 97 | bufchain_clear(&ps->pending_output_data); |
| 98 | bufchain_clear(&ps->pending_oob_output_data); |
| 99 | bufchain_add(&ps->pending_oob_output_data, data, len); |
| 100 | return len; |
| 101 | } |
| 102 | return sk_write_oob(ps->sub_socket, data, len); |
| 103 | } |
| 104 | |
| 105 | static void sk_proxy_flush (Socket s) |
| 106 | { |
| 107 | Proxy_Socket ps = (Proxy_Socket) s; |
| 108 | |
| 109 | if (ps->state != PROXY_STATE_ACTIVE) { |
| 110 | ps->pending_flush = 1; |
| 111 | return; |
| 112 | } |
| 113 | sk_flush(ps->sub_socket); |
| 114 | } |
| 115 | |
| 116 | static void sk_proxy_set_private_ptr (Socket s, void *ptr) |
| 117 | { |
| 118 | Proxy_Socket ps = (Proxy_Socket) s; |
| 119 | sk_set_private_ptr(ps->sub_socket, ptr); |
| 120 | } |
| 121 | |
| 122 | static void * sk_proxy_get_private_ptr (Socket s) |
| 123 | { |
| 124 | Proxy_Socket ps = (Proxy_Socket) s; |
| 125 | return sk_get_private_ptr(ps->sub_socket); |
| 126 | } |
| 127 | |
| 128 | static void sk_proxy_set_frozen (Socket s, int is_frozen) |
| 129 | { |
| 130 | Proxy_Socket ps = (Proxy_Socket) s; |
| 131 | |
| 132 | if (ps->state != PROXY_STATE_ACTIVE) { |
| 133 | ps->freeze = is_frozen; |
| 134 | return; |
| 135 | } |
| 136 | sk_set_frozen(ps->sub_socket, is_frozen); |
| 137 | } |
| 138 | |
| 139 | static char * sk_proxy_socket_error (Socket s) |
| 140 | { |
| 141 | Proxy_Socket ps = (Proxy_Socket) s; |
| 142 | if (ps->error != NULL || ps->sub_socket == NULL) { |
| 143 | return ps->error; |
| 144 | } |
| 145 | return sk_socket_error(ps->sub_socket); |
| 146 | } |
| 147 | |
| 148 | /* basic proxy plug functions */ |
| 149 | |
| 150 | static int plug_proxy_closing (Plug p, char *error_msg, |
| 151 | int error_code, int calling_back) |
| 152 | { |
| 153 | Proxy_Plug pp = (Proxy_Plug) p; |
| 154 | Proxy_Socket ps = pp->proxy_socket; |
| 155 | |
| 156 | if (ps->state != PROXY_STATE_ACTIVE) { |
| 157 | ps->closing_error_msg = error_msg; |
| 158 | ps->closing_error_code = error_code; |
| 159 | ps->closing_calling_back = calling_back; |
| 160 | return ps->negotiate(ps, PROXY_CHANGE_CLOSING); |
| 161 | } |
| 162 | return plug_closing(ps->plug, error_msg, |
| 163 | error_code, calling_back); |
| 164 | } |
| 165 | |
| 166 | static int plug_proxy_receive (Plug p, int urgent, char *data, int len) |
| 167 | { |
| 168 | Proxy_Plug pp = (Proxy_Plug) p; |
| 169 | Proxy_Socket ps = pp->proxy_socket; |
| 170 | |
| 171 | if (ps->state != PROXY_STATE_ACTIVE) { |
| 172 | /* we will lose the urgentness of this data, but since most, |
| 173 | * if not all, of this data will be consumed by the negotiation |
| 174 | * process, hopefully it won't affect the protocol above us |
| 175 | */ |
| 176 | bufchain_add(&ps->pending_input_data, data, len); |
| 177 | ps->receive_urgent = urgent; |
| 178 | ps->receive_data = data; |
| 179 | ps->receive_len = len; |
| 180 | return ps->negotiate(ps, PROXY_CHANGE_RECEIVE); |
| 181 | } |
| 182 | return plug_receive(ps->plug, urgent, data, len); |
| 183 | } |
| 184 | |
| 185 | static void plug_proxy_sent (Plug p, int bufsize) |
| 186 | { |
| 187 | Proxy_Plug pp = (Proxy_Plug) p; |
| 188 | Proxy_Socket ps = pp->proxy_socket; |
| 189 | |
| 190 | if (ps->state != PROXY_STATE_ACTIVE) { |
| 191 | ps->sent_bufsize = bufsize; |
| 192 | ps->negotiate(ps, PROXY_CHANGE_SENT); |
| 193 | return; |
| 194 | } |
| 195 | plug_sent(ps->plug, bufsize); |
| 196 | } |
| 197 | |
| 198 | static int plug_proxy_accepting (Plug p, void *sock) |
| 199 | { |
| 200 | Proxy_Plug pp = (Proxy_Plug) p; |
| 201 | Proxy_Socket ps = pp->proxy_socket; |
| 202 | |
| 203 | if (ps->state != PROXY_STATE_ACTIVE) { |
| 204 | ps->accepting_sock = sock; |
| 205 | return ps->negotiate(ps, PROXY_CHANGE_ACCEPTING); |
| 206 | } |
| 207 | return plug_accepting(ps->plug, sock); |
| 208 | } |
| 209 | |
| 210 | static int proxy_for_destination (SockAddr addr, char * hostname, int port) |
| 211 | { |
| 212 | int s = 0, e = 0; |
| 213 | char hostip[64]; |
| 214 | int hostip_len, hostname_len; |
| 215 | char * exclude_list; |
| 216 | |
| 217 | /* we want a string representation of the IP address for comparisons */ |
| 218 | sk_getaddr(addr, hostip, 64); |
| 219 | |
| 220 | hostip_len = strlen(hostip); |
| 221 | hostname_len = strlen(hostname); |
| 222 | |
| 223 | exclude_list = cfg.proxy_exclude_list; |
| 224 | |
| 225 | /* now parse the exclude list, and see if either our IP |
| 226 | * or hostname matches anything in it. |
| 227 | */ |
| 228 | |
| 229 | while (exclude_list[s]) { |
| 230 | while (exclude_list[s] && |
| 231 | (isspace(exclude_list[s]) || |
| 232 | exclude_list[s] == ',')) s++; |
| 233 | |
| 234 | if (!exclude_list[s]) break; |
| 235 | |
| 236 | e = s; |
| 237 | |
| 238 | while (exclude_list[e] && |
| 239 | (isalnum(exclude_list[e]) || |
| 240 | exclude_list[e] == '-' || |
| 241 | exclude_list[e] == '.' || |
| 242 | exclude_list[e] == '*')) e++; |
| 243 | |
| 244 | if (exclude_list[s] == '*') { |
| 245 | /* wildcard at beginning of entry */ |
| 246 | |
| 247 | if (strnicmp(hostip + hostip_len - (e - s - 1), |
| 248 | exclude_list + s + 1, e - s - 1) == 0 || |
| 249 | strnicmp(hostname + hostname_len - (e - s - 1), |
| 250 | exclude_list + s + 1, e - s - 1) == 0) |
| 251 | return 0; /* IP/hostname range excluded. do not use proxy. */ |
| 252 | |
| 253 | } else if (exclude_list[e-1] == '*') { |
| 254 | /* wildcard at end of entry */ |
| 255 | |
| 256 | if (strnicmp(hostip, exclude_list + s, e - s - 1) == 0 || |
| 257 | strnicmp(hostname, exclude_list + s, e - s - 1) == 0) |
| 258 | return 0; /* IP/hostname range excluded. do not use proxy. */ |
| 259 | |
| 260 | } else { |
| 261 | /* no wildcard at either end, so let's try an absolute |
| 262 | * match (ie. a specific IP) |
| 263 | */ |
| 264 | |
| 265 | if (stricmp(hostip, exclude_list + s) == 0) |
| 266 | return 0; /* IP/hostname excluded. do not use proxy. */ |
| 267 | if (stricmp(hostname, exclude_list + s) == 0) |
| 268 | return 0; /* IP/hostname excluded. do not use proxy. */ |
| 269 | } |
| 270 | |
| 271 | s = e; |
| 272 | } |
| 273 | |
| 274 | /* no matches in the exclude list, so use the proxy */ |
| 275 | return 1; |
| 276 | } |
| 277 | |
| 278 | Socket new_connection(SockAddr addr, char *hostname, |
| 279 | int port, int privport, |
| 280 | int oobinline, int nodelay, Plug plug) |
| 281 | { |
| 282 | static struct socket_function_table socket_fn_table = { |
| 283 | sk_proxy_plug, |
| 284 | sk_proxy_close, |
| 285 | sk_proxy_write, |
| 286 | sk_proxy_write_oob, |
| 287 | sk_proxy_flush, |
| 288 | sk_proxy_set_private_ptr, |
| 289 | sk_proxy_get_private_ptr, |
| 290 | sk_proxy_set_frozen, |
| 291 | sk_proxy_socket_error |
| 292 | }; |
| 293 | |
| 294 | static struct plug_function_table plug_fn_table = { |
| 295 | plug_proxy_closing, |
| 296 | plug_proxy_receive, |
| 297 | plug_proxy_sent, |
| 298 | plug_proxy_accepting |
| 299 | }; |
| 300 | |
| 301 | if (cfg.proxy_type != PROXY_NONE && |
| 302 | proxy_for_destination(addr, hostname, port)) |
| 303 | { |
| 304 | Proxy_Socket ret; |
| 305 | Proxy_Plug pplug; |
| 306 | SockAddr proxy_addr; |
| 307 | char * proxy_canonical_name; |
| 308 | |
| 309 | ret = smalloc(sizeof(struct Socket_proxy_tag)); |
| 310 | ret->fn = &socket_fn_table; |
| 311 | ret->plug = plug; |
| 312 | ret->remote_addr = addr; |
| 313 | ret->remote_port = port; |
| 314 | |
| 315 | bufchain_init(&ret->pending_input_data); |
| 316 | bufchain_init(&ret->pending_output_data); |
| 317 | bufchain_init(&ret->pending_oob_output_data); |
| 318 | |
| 319 | ret->sub_socket = NULL; |
| 320 | ret->state = PROXY_STATE_NEW; |
| 321 | |
| 322 | if (cfg.proxy_type == PROXY_HTTP) { |
| 323 | ret->negotiate = proxy_http_negotiate; |
| 324 | } else if (cfg.proxy_type == PROXY_SOCKS) { |
| 325 | if (cfg.proxy_socks_version == 4) |
| 326 | ret->negotiate = proxy_socks4_negotiate; |
| 327 | else |
| 328 | ret->negotiate = proxy_socks5_negotiate; |
| 329 | } else if (cfg.proxy_type == PROXY_TELNET) { |
| 330 | ret->negotiate = proxy_telnet_negotiate; |
| 331 | } else { |
| 332 | ret->error = "Network error: Unknown proxy method"; |
| 333 | return (Socket) ret; |
| 334 | } |
| 335 | |
| 336 | /* create the proxy plug to map calls from the actual |
| 337 | * socket into our proxy socket layer */ |
| 338 | pplug = smalloc(sizeof(struct Plug_proxy_tag)); |
| 339 | pplug->fn = &plug_fn_table; |
| 340 | pplug->proxy_socket = ret; |
| 341 | |
| 342 | /* look-up proxy */ |
| 343 | proxy_addr = sk_namelookup(cfg.proxy_host, |
| 344 | &proxy_canonical_name); |
| 345 | sfree(proxy_canonical_name); |
| 346 | |
| 347 | /* create the actual socket we will be using, |
| 348 | * connected to our proxy server and port. |
| 349 | */ |
| 350 | ret->sub_socket = sk_new(proxy_addr, cfg.proxy_port, |
| 351 | privport, oobinline, |
| 352 | nodelay, (Plug) pplug); |
| 353 | if (sk_socket_error(ret->sub_socket) != NULL) |
| 354 | return (Socket) ret; |
| 355 | |
| 356 | sk_addr_free(proxy_addr); |
| 357 | |
| 358 | /* start the proxy negotiation process... */ |
| 359 | sk_set_frozen(ret->sub_socket, 0); |
| 360 | ret->negotiate(ret, PROXY_CHANGE_NEW); |
| 361 | |
| 362 | return (Socket) ret; |
| 363 | } |
| 364 | |
| 365 | /* no proxy, so just return the direct socket */ |
| 366 | return sk_new(addr, port, privport, oobinline, nodelay, plug); |
| 367 | } |
| 368 | |
| 369 | Socket new_listener(int port, Plug plug, int local_host_only) |
| 370 | { |
| 371 | /* TODO: SOCKS (and potentially others) support inbound |
| 372 | * TODO: connections via the proxy. support them. |
| 373 | */ |
| 374 | |
| 375 | return sk_newlistener(port, plug, local_host_only); |
| 376 | } |
| 377 | |
| 378 | /* ---------------------------------------------------------------------- |
| 379 | * HTTP CONNECT proxy type. |
| 380 | */ |
| 381 | |
| 382 | static int get_line_end (char * data, int len) |
| 383 | { |
| 384 | int off = 0; |
| 385 | |
| 386 | while (off < len) |
| 387 | { |
| 388 | if (data[off] == '\n') { |
| 389 | /* we have a newline */ |
| 390 | off++; |
| 391 | |
| 392 | /* is that the only thing on this line? */ |
| 393 | if (off <= 2) return off; |
| 394 | |
| 395 | /* if not, then there is the possibility that this header |
| 396 | * continues onto the next line, if it starts with a space |
| 397 | * or a tab. |
| 398 | */ |
| 399 | |
| 400 | if (off + 1 < len && |
| 401 | data[off+1] != ' ' && |
| 402 | data[off+1] != '\t') return off; |
| 403 | |
| 404 | /* the line does continue, so we have to keep going |
| 405 | * until we see an the header's "real" end of line. |
| 406 | */ |
| 407 | off++; |
| 408 | } |
| 409 | |
| 410 | off++; |
| 411 | } |
| 412 | |
| 413 | return -1; |
| 414 | } |
| 415 | |
| 416 | int proxy_http_negotiate (Proxy_Socket p, int change) |
| 417 | { |
| 418 | if (p->state == PROXY_STATE_NEW) { |
| 419 | /* we are just beginning the proxy negotiate process, |
| 420 | * so we'll send off the initial bits of the request. |
| 421 | * for this proxy method, it's just a simple HTTP |
| 422 | * request |
| 423 | */ |
| 424 | char buf[256], dest[64]; |
| 425 | |
| 426 | sk_getaddr(p->remote_addr, dest, 64); |
| 427 | |
| 428 | sprintf(buf, "CONNECT %s:%i HTTP/1.1\r\nHost: %s:%i\r\n\r\n", |
| 429 | dest, p->remote_port, dest, p->remote_port); |
| 430 | sk_write(p->sub_socket, buf, strlen(buf)); |
| 431 | |
| 432 | p->state = 1; |
| 433 | return 0; |
| 434 | } |
| 435 | |
| 436 | if (change == PROXY_CHANGE_CLOSING) { |
| 437 | /* if our proxy negotiation process involves closing and opening |
| 438 | * new sockets, then we would want to intercept this closing |
| 439 | * callback when we were expecting it. if we aren't anticipating |
| 440 | * a socket close, then some error must have occurred. we'll |
| 441 | * just pass those errors up to the backend. |
| 442 | */ |
| 443 | return plug_closing(p->plug, p->closing_error_msg, |
| 444 | p->closing_error_code, |
| 445 | p->closing_calling_back); |
| 446 | } |
| 447 | |
| 448 | if (change == PROXY_CHANGE_SENT) { |
| 449 | /* some (or all) of what we wrote to the proxy was sent. |
| 450 | * we don't do anything new, however, until we receive the |
| 451 | * proxy's response. we might want to set a timer so we can |
| 452 | * timeout the proxy negotiation after a while... |
| 453 | */ |
| 454 | return 0; |
| 455 | } |
| 456 | |
| 457 | if (change == PROXY_CHANGE_ACCEPTING) { |
| 458 | /* we should _never_ see this, as we are using our socket to |
| 459 | * connect to a proxy, not accepting inbound connections. |
| 460 | * what should we do? close the socket with an appropriate |
| 461 | * error message? |
| 462 | */ |
| 463 | return plug_accepting(p->plug, p->accepting_sock); |
| 464 | } |
| 465 | |
| 466 | if (change == PROXY_CHANGE_RECEIVE) { |
| 467 | /* we have received data from the underlying socket, which |
| 468 | * we'll need to parse, process, and respond to appropriately. |
| 469 | */ |
| 470 | |
| 471 | void *data; |
| 472 | int len; |
| 473 | int eol; |
| 474 | |
| 475 | if (p->state == 1) { |
| 476 | |
| 477 | int min_ver, maj_ver, status; |
| 478 | |
| 479 | /* get the status line */ |
| 480 | bufchain_prefix(&p->pending_input_data, &data, &len); |
| 481 | eol = get_line_end(data, len); |
| 482 | if (eol < 0) return 1; |
| 483 | |
| 484 | sscanf((char *)data, "HTTP/%i.%i %i", &maj_ver, &min_ver, &status); |
| 485 | |
| 486 | /* remove the status line from the input buffer. */ |
| 487 | bufchain_consume(&p->pending_input_data, eol); |
| 488 | |
| 489 | /* TODO: we need to support Proxy-Auth headers */ |
| 490 | |
| 491 | if (status < 200 || status > 299) { |
| 492 | /* error */ |
| 493 | /* TODO: return a more specific error message, |
| 494 | * TODO: based on the status code. |
| 495 | */ |
| 496 | plug_closing(p->plug, "Network error: Error while communicating with proxy", |
| 497 | PROXY_ERROR_GENERAL, 0); |
| 498 | return 1; |
| 499 | } |
| 500 | |
| 501 | p->state = 2; |
| 502 | } |
| 503 | |
| 504 | if (p->state == 2) { |
| 505 | |
| 506 | /* get headers. we're done when we get a |
| 507 | * header of length 2, (ie. just "\r\n") |
| 508 | */ |
| 509 | |
| 510 | bufchain_prefix(&p->pending_input_data, &data, &len); |
| 511 | eol = get_line_end(data, len); |
| 512 | while (eol > 2) |
| 513 | { |
| 514 | /* TODO: Proxy-Auth stuff. in some cases, we will |
| 515 | * TODO: need to extract information from headers. |
| 516 | */ |
| 517 | bufchain_consume(&p->pending_input_data, eol); |
| 518 | bufchain_prefix(&p->pending_input_data, &data, &len); |
| 519 | eol = get_line_end(data, len); |
| 520 | } |
| 521 | |
| 522 | if (eol == 2) { |
| 523 | /* we're done */ |
| 524 | bufchain_consume(&p->pending_input_data, 2); |
| 525 | proxy_activate(p); |
| 526 | /* proxy activate will have dealt with |
| 527 | * whatever is left of the buffer */ |
| 528 | return 1; |
| 529 | } |
| 530 | |
| 531 | return 1; |
| 532 | } |
| 533 | } |
| 534 | |
| 535 | plug_closing(p->plug, "Network error: Unexpected proxy error", |
| 536 | PROXY_ERROR_UNEXPECTED, 0); |
| 537 | return 1; |
| 538 | } |
| 539 | |
| 540 | /* ---------------------------------------------------------------------- |
| 541 | * SOCKS proxy type. |
| 542 | */ |
| 543 | |
| 544 | /* SOCKS version 4 */ |
| 545 | int proxy_socks4_negotiate (Proxy_Socket p, int change) |
| 546 | { |
| 547 | if (p->state == PROXY_CHANGE_NEW) { |
| 548 | |
| 549 | /* request format: |
| 550 | * version number (1 byte) = 4 |
| 551 | * command code (1 byte) |
| 552 | * 1 = CONNECT |
| 553 | * 2 = BIND |
| 554 | * dest. port (2 bytes) [network order] |
| 555 | * dest. address (4 bytes) |
| 556 | * user ID (variable length, null terminated string) |
| 557 | */ |
| 558 | |
| 559 | int length; |
| 560 | char * command; |
| 561 | |
| 562 | if (sk_addrtype(p->remote_addr) != AF_INET) { |
| 563 | plug_closing(p->plug, "Network error: SOCKS version 4 does not support IPv6", |
| 564 | PROXY_ERROR_GENERAL, 0); |
| 565 | return 1; |
| 566 | } |
| 567 | |
| 568 | length = strlen(cfg.proxy_username) + 9; |
| 569 | command = (char*) malloc(length); |
| 570 | strcpy(command + 8, cfg.proxy_username); |
| 571 | |
| 572 | command[0] = 4; /* version 4 */ |
| 573 | command[1] = 1; /* CONNECT command */ |
| 574 | |
| 575 | /* port */ |
| 576 | command[2] = (char) (p->remote_port >> 8) & 0xff; |
| 577 | command[3] = (char) p->remote_port & 0xff; |
| 578 | |
| 579 | /* address */ |
| 580 | sk_addrcopy(p->remote_addr, command + 4); |
| 581 | |
| 582 | sk_write(p->sub_socket, command, length); |
| 583 | free(command); |
| 584 | |
| 585 | p->state = 1; |
| 586 | return 0; |
| 587 | } |
| 588 | |
| 589 | if (change == PROXY_CHANGE_CLOSING) { |
| 590 | /* if our proxy negotiation process involves closing and opening |
| 591 | * new sockets, then we would want to intercept this closing |
| 592 | * callback when we were expecting it. if we aren't anticipating |
| 593 | * a socket close, then some error must have occurred. we'll |
| 594 | * just pass those errors up to the backend. |
| 595 | */ |
| 596 | return plug_closing(p->plug, p->closing_error_msg, |
| 597 | p->closing_error_code, |
| 598 | p->closing_calling_back); |
| 599 | } |
| 600 | |
| 601 | if (change == PROXY_CHANGE_SENT) { |
| 602 | /* some (or all) of what we wrote to the proxy was sent. |
| 603 | * we don't do anything new, however, until we receive the |
| 604 | * proxy's response. we might want to set a timer so we can |
| 605 | * timeout the proxy negotiation after a while... |
| 606 | */ |
| 607 | return 0; |
| 608 | } |
| 609 | |
| 610 | if (change == PROXY_CHANGE_ACCEPTING) { |
| 611 | /* we should _never_ see this, as we are using our socket to |
| 612 | * connect to a proxy, not accepting inbound connections. |
| 613 | * what should we do? close the socket with an appropriate |
| 614 | * error message? |
| 615 | */ |
| 616 | return plug_accepting(p->plug, p->accepting_sock); |
| 617 | } |
| 618 | |
| 619 | if (change == PROXY_CHANGE_RECEIVE) { |
| 620 | /* we have received data from the underlying socket, which |
| 621 | * we'll need to parse, process, and respond to appropriately. |
| 622 | */ |
| 623 | |
| 624 | if (p->state == 1) { |
| 625 | /* response format: |
| 626 | * version number (1 byte) = 4 |
| 627 | * reply code (1 byte) |
| 628 | * 90 = request granted |
| 629 | * 91 = request rejected or failed |
| 630 | * 92 = request rejected due to lack of IDENTD on client |
| 631 | * 93 = request rejected due to difference in user ID |
| 632 | * (what we sent vs. what IDENTD said) |
| 633 | * dest. port (2 bytes) |
| 634 | * dest. address (4 bytes) |
| 635 | */ |
| 636 | |
| 637 | char *data; |
| 638 | int len; |
| 639 | |
| 640 | /* get the response */ |
| 641 | bufchain_prefix(&p->pending_input_data, &data, &len); |
| 642 | |
| 643 | if (data[0] != 0) { |
| 644 | plug_closing(p->plug, "Network error: SOCKS proxy responded with " |
| 645 | "unexpected reply code version", |
| 646 | PROXY_ERROR_GENERAL, 0); |
| 647 | return 1; |
| 648 | } |
| 649 | |
| 650 | if (data[1] != 90) { |
| 651 | |
| 652 | switch (data[1]) { |
| 653 | case 92: |
| 654 | plug_closing(p->plug, "Network error: SOCKS server wanted IDENTD on client", |
| 655 | PROXY_ERROR_GENERAL, 0); |
| 656 | break; |
| 657 | case 93: |
| 658 | plug_closing(p->plug, "Network error: Username and IDENTD on client don't agree", |
| 659 | PROXY_ERROR_GENERAL, 0); |
| 660 | break; |
| 661 | case 91: |
| 662 | default: |
| 663 | plug_closing(p->plug, "Network error: Error while communicating with proxy", |
| 664 | PROXY_ERROR_GENERAL, 0); |
| 665 | break; |
| 666 | } |
| 667 | |
| 668 | return 1; |
| 669 | } |
| 670 | |
| 671 | /* we're done */ |
| 672 | proxy_activate(p); |
| 673 | /* proxy activate will have dealt with |
| 674 | * whatever is left of the buffer */ |
| 675 | return 1; |
| 676 | } |
| 677 | } |
| 678 | |
| 679 | plug_closing(p->plug, "Network error: Unexpected proxy error", |
| 680 | PROXY_ERROR_UNEXPECTED, 0); |
| 681 | return 1; |
| 682 | } |
| 683 | |
| 684 | /* SOCKS version 5 */ |
| 685 | int proxy_socks5_negotiate (Proxy_Socket p, int change) |
| 686 | { |
| 687 | if (p->state == PROXY_CHANGE_NEW) { |
| 688 | |
| 689 | /* initial command: |
| 690 | * version number (1 byte) = 5 |
| 691 | * number of available authentication methods (1 byte) |
| 692 | * available authentication methods (1 byte * previous value) |
| 693 | * authentication methods: |
| 694 | * 0x00 = no authentication |
| 695 | * 0x01 = GSSAPI |
| 696 | * 0x02 = username/password |
| 697 | * 0x03 = CHAP |
| 698 | */ |
| 699 | |
| 700 | char command[3]; |
| 701 | |
| 702 | command[0] = 5; /* version 5 */ |
| 703 | command[1] = 1; /* TODO: we don't currently support any auth methods */ |
| 704 | command[2] = 0x00; /* no authentication */ |
| 705 | |
| 706 | sk_write(p->sub_socket, command, 3); |
| 707 | |
| 708 | p->state = 1; |
| 709 | return 0; |
| 710 | } |
| 711 | |
| 712 | if (change == PROXY_CHANGE_CLOSING) { |
| 713 | /* if our proxy negotiation process involves closing and opening |
| 714 | * new sockets, then we would want to intercept this closing |
| 715 | * callback when we were expecting it. if we aren't anticipating |
| 716 | * a socket close, then some error must have occurred. we'll |
| 717 | * just pass those errors up to the backend. |
| 718 | */ |
| 719 | return plug_closing(p->plug, p->closing_error_msg, |
| 720 | p->closing_error_code, |
| 721 | p->closing_calling_back); |
| 722 | } |
| 723 | |
| 724 | if (change == PROXY_CHANGE_SENT) { |
| 725 | /* some (or all) of what we wrote to the proxy was sent. |
| 726 | * we don't do anything new, however, until we receive the |
| 727 | * proxy's response. we might want to set a timer so we can |
| 728 | * timeout the proxy negotiation after a while... |
| 729 | */ |
| 730 | return 0; |
| 731 | } |
| 732 | |
| 733 | if (change == PROXY_CHANGE_ACCEPTING) { |
| 734 | /* we should _never_ see this, as we are using our socket to |
| 735 | * connect to a proxy, not accepting inbound connections. |
| 736 | * what should we do? close the socket with an appropriate |
| 737 | * error message? |
| 738 | */ |
| 739 | return plug_accepting(p->plug, p->accepting_sock); |
| 740 | } |
| 741 | |
| 742 | if (change == PROXY_CHANGE_RECEIVE) { |
| 743 | /* we have received data from the underlying socket, which |
| 744 | * we'll need to parse, process, and respond to appropriately. |
| 745 | */ |
| 746 | |
| 747 | char *data; |
| 748 | int len; |
| 749 | |
| 750 | if (p->state == 1) { |
| 751 | |
| 752 | /* initial response: |
| 753 | * version number (1 byte) = 5 |
| 754 | * authentication method (1 byte) |
| 755 | * authentication methods: |
| 756 | * 0x00 = no authentication |
| 757 | * 0x01 = GSSAPI |
| 758 | * 0x02 = username/password |
| 759 | * 0x03 = CHAP |
| 760 | * 0xff = no acceptable methods |
| 761 | */ |
| 762 | |
| 763 | /* get the response */ |
| 764 | bufchain_prefix(&p->pending_input_data, &data, &len); |
| 765 | |
| 766 | if (data[0] != 5) { |
| 767 | plug_closing(p->plug, "Network error: Error while communicating with proxy", |
| 768 | PROXY_ERROR_GENERAL, 0); |
| 769 | return 1; |
| 770 | } |
| 771 | |
| 772 | if (data[1] == 0x00) p->state = 2; /* no authentication needed */ |
| 773 | else if (data[1] == 0x01) p->state = 4; /* GSSAPI authentication */ |
| 774 | else if (data[1] == 0x02) p->state = 5; /* username/password authentication */ |
| 775 | else if (data[1] == 0x03) p->state = 6; /* CHAP authentication */ |
| 776 | else { |
| 777 | plug_closing(p->plug, "Network error: We don't support any of the SOCKS " |
| 778 | "server's authentication methods", |
| 779 | PROXY_ERROR_GENERAL, 0); |
| 780 | return 1; |
| 781 | } |
| 782 | } |
| 783 | |
| 784 | if (p->state == 2) { |
| 785 | |
| 786 | /* request format: |
| 787 | * version number (1 byte) = 5 |
| 788 | * command code (1 byte) |
| 789 | * 1 = CONNECT |
| 790 | * 2 = BIND |
| 791 | * 3 = UDP ASSOCIATE |
| 792 | * reserved (1 byte) = 0x00 |
| 793 | * address type (1 byte) |
| 794 | * 1 = IPv4 |
| 795 | * 3 = domainname (first byte has length, no terminating null) |
| 796 | * 4 = IPv6 |
| 797 | * dest. address (variable) |
| 798 | * dest. port (2 bytes) [network order] |
| 799 | */ |
| 800 | |
| 801 | char command[22]; |
| 802 | int len; |
| 803 | |
| 804 | if (sk_addrtype(p->remote_addr) == AF_INET) { |
| 805 | len = 10; |
| 806 | command[3] = 1; /* IPv4 */ |
| 807 | } else { |
| 808 | len = 22; |
| 809 | command[3] = 4; /* IPv6 */ |
| 810 | } |
| 811 | |
| 812 | command[0] = 5; /* version 5 */ |
| 813 | command[1] = 1; /* CONNECT command */ |
| 814 | command[2] = 0x00; |
| 815 | |
| 816 | /* address */ |
| 817 | sk_addrcopy(p->remote_addr, command+4); |
| 818 | |
| 819 | /* port */ |
| 820 | command[len-2] = (char) (p->remote_port >> 8) & 0xff; |
| 821 | command[len-1] = (char) p->remote_port & 0xff; |
| 822 | |
| 823 | sk_write(p->sub_socket, command, len); |
| 824 | |
| 825 | p->state = 3; |
| 826 | return 1; |
| 827 | } |
| 828 | |
| 829 | if (p->state == 3) { |
| 830 | |
| 831 | /* reply format: |
| 832 | * version number (1 bytes) = 5 |
| 833 | * reply code (1 byte) |
| 834 | * 0 = succeeded |
| 835 | * 1 = general SOCKS server failure |
| 836 | * 2 = connection not allowed by ruleset |
| 837 | * 3 = network unreachable |
| 838 | * 4 = host unreachable |
| 839 | * 5 = connection refused |
| 840 | * 6 = TTL expired |
| 841 | * 7 = command not supported |
| 842 | * 8 = address type not supported |
| 843 | * reserved (1 byte) = x00 |
| 844 | * address type (1 byte) |
| 845 | * 1 = IPv4 |
| 846 | * 3 = domainname (first byte has length, no terminating null) |
| 847 | * 4 = IPv6 |
| 848 | * server bound address (variable) |
| 849 | * server bound port (2 bytes) [network order] |
| 850 | */ |
| 851 | |
| 852 | /* get the response */ |
| 853 | bufchain_prefix(&p->pending_input_data, &data, &len); |
| 854 | |
| 855 | if (data[0] != 5) { |
| 856 | plug_closing(p->plug, "Network error: Error while communicating with proxy", |
| 857 | PROXY_ERROR_GENERAL, 0); |
| 858 | return 1; |
| 859 | } |
| 860 | |
| 861 | if (data[1] != 0) { |
| 862 | |
| 863 | switch (data[1]) { |
| 864 | case 1: |
| 865 | case 2: |
| 866 | case 3: |
| 867 | case 4: |
| 868 | case 5: |
| 869 | case 6: |
| 870 | case 7: |
| 871 | case 8: |
| 872 | default: |
| 873 | plug_closing(p->plug, "Network error: Error while communicating with proxy", |
| 874 | PROXY_ERROR_GENERAL, 0); |
| 875 | break; |
| 876 | } |
| 877 | |
| 878 | return 1; |
| 879 | } |
| 880 | |
| 881 | /* we're done */ |
| 882 | proxy_activate(p); |
| 883 | /* proxy activate will have dealt with |
| 884 | * whatever is left of the buffer */ |
| 885 | return 1; |
| 886 | } |
| 887 | |
| 888 | if (p->state == 4) { |
| 889 | /* TODO: Handle GSSAPI authentication */ |
| 890 | plug_closing(p->plug, "Network error: We don't support GSSAPI authentication", |
| 891 | PROXY_ERROR_GENERAL, 0); |
| 892 | return 1; |
| 893 | } |
| 894 | |
| 895 | if (p->state == 5) { |
| 896 | /* TODO: Handle username/password authentication */ |
| 897 | plug_closing(p->plug, "Network error: We don't support username/password " |
| 898 | "authentication", |
| 899 | PROXY_ERROR_GENERAL, 0); |
| 900 | return 1; |
| 901 | } |
| 902 | |
| 903 | if (p->state == 6) { |
| 904 | /* TODO: Handle CHAP authentication */ |
| 905 | plug_closing(p->plug, "Network error: We don't support CHAP authentication", |
| 906 | PROXY_ERROR_GENERAL, 0); |
| 907 | return 1; |
| 908 | } |
| 909 | } |
| 910 | |
| 911 | plug_closing(p->plug, "Network error: Unexpected proxy error", |
| 912 | PROXY_ERROR_UNEXPECTED, 0); |
| 913 | return 1; |
| 914 | } |
| 915 | |
| 916 | /* ---------------------------------------------------------------------- |
| 917 | * `Telnet' proxy type. |
| 918 | * |
| 919 | * (This is for ad-hoc proxies where you connect to the proxy's |
| 920 | * telnet port and send a command such as `connect host port'. The |
| 921 | * command is configurable, since this proxy type is typically not |
| 922 | * standardised or at all well-defined.) |
| 923 | */ |
| 924 | |
| 925 | int proxy_telnet_negotiate (Proxy_Socket p, int change) |
| 926 | { |
| 927 | if (p->state == PROXY_CHANGE_NEW) { |
| 928 | |
| 929 | int so = 0, eo = 0; |
| 930 | |
| 931 | /* we need to escape \\, \%, \r, \n, \t, \x??, \0???, |
| 932 | * %%, %host, and %port |
| 933 | */ |
| 934 | |
| 935 | while (cfg.proxy_telnet_command[eo] != 0) { |
| 936 | |
| 937 | /* scan forward until we hit end-of-line, |
| 938 | * or an escape character (\ or %) */ |
| 939 | while (cfg.proxy_telnet_command[eo] != 0 && |
| 940 | cfg.proxy_telnet_command[eo] != '%' && |
| 941 | cfg.proxy_telnet_command[eo] != '\\') eo++; |
| 942 | |
| 943 | /* if we hit eol, break out of our escaping loop */ |
| 944 | if (cfg.proxy_telnet_command[eo] == 0) break; |
| 945 | |
| 946 | /* if there was any unescaped text before the escape |
| 947 | * character, send that now */ |
| 948 | if (eo != so) { |
| 949 | sk_write(p->sub_socket, |
| 950 | cfg.proxy_telnet_command + so, eo - so); |
| 951 | } |
| 952 | |
| 953 | so = eo++; |
| 954 | |
| 955 | /* if the escape character was the last character of |
| 956 | * the line, we'll just stop and send it. */ |
| 957 | if (cfg.proxy_telnet_command[eo] == 0) break; |
| 958 | |
| 959 | if (cfg.proxy_telnet_command[so] == '\\') { |
| 960 | |
| 961 | /* we recognize \\, \%, \r, \n, \t, \x??. |
| 962 | * anything else, we just send unescaped (including the \). |
| 963 | */ |
| 964 | |
| 965 | switch (cfg.proxy_telnet_command[eo]) { |
| 966 | |
| 967 | case '\\': |
| 968 | sk_write(p->sub_socket, "\\", 1); |
| 969 | eo++; |
| 970 | break; |
| 971 | |
| 972 | case '%': |
| 973 | sk_write(p->sub_socket, "%%", 1); |
| 974 | eo++; |
| 975 | break; |
| 976 | |
| 977 | case 'r': |
| 978 | sk_write(p->sub_socket, "\r", 1); |
| 979 | eo++; |
| 980 | break; |
| 981 | |
| 982 | case 'n': |
| 983 | sk_write(p->sub_socket, "\n", 1); |
| 984 | eo++; |
| 985 | break; |
| 986 | |
| 987 | case 't': |
| 988 | sk_write(p->sub_socket, "\t", 1); |
| 989 | eo++; |
| 990 | break; |
| 991 | |
| 992 | case 'x': |
| 993 | case 'X': |
| 994 | { |
| 995 | /* escaped hexadecimal value (ie. \xff) */ |
| 996 | unsigned char v = 0; |
| 997 | int i = 0; |
| 998 | |
| 999 | for (;;) { |
| 1000 | eo++; |
| 1001 | if (cfg.proxy_telnet_command[eo] >= '0' && |
| 1002 | cfg.proxy_telnet_command[eo] <= '9') |
| 1003 | v += cfg.proxy_telnet_command[eo] - '0'; |
| 1004 | else if (cfg.proxy_telnet_command[eo] >= 'a' && |
| 1005 | cfg.proxy_telnet_command[eo] <= 'f') |
| 1006 | v += cfg.proxy_telnet_command[eo] - 'a' + 10; |
| 1007 | else if (cfg.proxy_telnet_command[eo] >= 'A' && |
| 1008 | cfg.proxy_telnet_command[eo] <= 'F') |
| 1009 | v += cfg.proxy_telnet_command[eo] - 'A' + 10; |
| 1010 | else { |
| 1011 | /* non hex character, so we abort and just |
| 1012 | * send the whole thing unescaped (including \x) |
| 1013 | */ |
| 1014 | sk_write(p->sub_socket, "\\", 1); |
| 1015 | eo = so + 1; |
| 1016 | break; |
| 1017 | } |
| 1018 | |
| 1019 | /* we only extract two hex characters */ |
| 1020 | if (i == 1) { |
| 1021 | sk_write(p->sub_socket, &v, 1); |
| 1022 | eo++; |
| 1023 | break; |
| 1024 | } |
| 1025 | |
| 1026 | i++; |
| 1027 | v <<= 4; |
| 1028 | } |
| 1029 | } |
| 1030 | break; |
| 1031 | |
| 1032 | default: |
| 1033 | sk_write(p->sub_socket, |
| 1034 | cfg.proxy_telnet_command + so, 2); |
| 1035 | eo++; |
| 1036 | break; |
| 1037 | } |
| 1038 | } else { |
| 1039 | |
| 1040 | /* % escape. we recognize %%, %host, %port. anything else, |
| 1041 | * we just send unescaped (including the %). */ |
| 1042 | |
| 1043 | if (cfg.proxy_telnet_command[eo] == '%') { |
| 1044 | sk_write(p->sub_socket, "%", 1); |
| 1045 | eo++; |
| 1046 | } |
| 1047 | else if (strnicmp(cfg.proxy_telnet_command + eo, |
| 1048 | "host", 4) == 0) { |
| 1049 | char dest[64]; |
| 1050 | sk_getaddr(p->remote_addr, dest, 64); |
| 1051 | sk_write(p->sub_socket, dest, strlen(dest)); |
| 1052 | eo += 4; |
| 1053 | } |
| 1054 | else if (strnicmp(cfg.proxy_telnet_command + eo, |
| 1055 | "port", 4) == 0) { |
| 1056 | char port[8]; |
| 1057 | sprintf(port, "%i", p->remote_port); |
| 1058 | sk_write(p->sub_socket, port, strlen(port)); |
| 1059 | eo += 4; |
| 1060 | } |
| 1061 | else { |
| 1062 | /* we don't escape this, so send the % now, and |
| 1063 | * don't advance eo, so that we'll consider the |
| 1064 | * text immediately following the % as unescaped. |
| 1065 | */ |
| 1066 | sk_write(p->sub_socket, "%", 1); |
| 1067 | } |
| 1068 | } |
| 1069 | |
| 1070 | /* resume scanning for additional escapes after this one. */ |
| 1071 | so = eo; |
| 1072 | } |
| 1073 | |
| 1074 | /* if there is any unescaped text at the end of the line, send it */ |
| 1075 | if (eo != so) { |
| 1076 | sk_write(p->sub_socket, cfg.proxy_telnet_command + so, eo - so); |
| 1077 | } |
| 1078 | |
| 1079 | p->state = 1; |
| 1080 | return 0; |
| 1081 | } |
| 1082 | |
| 1083 | if (change == PROXY_CHANGE_CLOSING) { |
| 1084 | /* if our proxy negotiation process involves closing and opening |
| 1085 | * new sockets, then we would want to intercept this closing |
| 1086 | * callback when we were expecting it. if we aren't anticipating |
| 1087 | * a socket close, then some error must have occurred. we'll |
| 1088 | * just pass those errors up to the backend. |
| 1089 | */ |
| 1090 | return plug_closing(p->plug, p->closing_error_msg, |
| 1091 | p->closing_error_code, |
| 1092 | p->closing_calling_back); |
| 1093 | } |
| 1094 | |
| 1095 | if (change == PROXY_CHANGE_SENT) { |
| 1096 | /* some (or all) of what we wrote to the proxy was sent. |
| 1097 | * we don't do anything new, however, until we receive the |
| 1098 | * proxy's response. we might want to set a timer so we can |
| 1099 | * timeout the proxy negotiation after a while... |
| 1100 | */ |
| 1101 | return 0; |
| 1102 | } |
| 1103 | |
| 1104 | if (change == PROXY_CHANGE_ACCEPTING) { |
| 1105 | /* we should _never_ see this, as we are using our socket to |
| 1106 | * connect to a proxy, not accepting inbound connections. |
| 1107 | * what should we do? close the socket with an appropriate |
| 1108 | * error message? |
| 1109 | */ |
| 1110 | return plug_accepting(p->plug, p->accepting_sock); |
| 1111 | } |
| 1112 | |
| 1113 | if (change == PROXY_CHANGE_RECEIVE) { |
| 1114 | /* we have received data from the underlying socket, which |
| 1115 | * we'll need to parse, process, and respond to appropriately. |
| 1116 | */ |
| 1117 | |
| 1118 | /* we're done */ |
| 1119 | proxy_activate(p); |
| 1120 | /* proxy activate will have dealt with |
| 1121 | * whatever is left of the buffer */ |
| 1122 | return 1; |
| 1123 | } |
| 1124 | |
| 1125 | plug_closing(p->plug, "Network error: Unexpected proxy error", |
| 1126 | PROXY_ERROR_UNEXPECTED, 0); |
| 1127 | return 1; |
| 1128 | } |