| 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 <assert.h> |
| 9 | #include <ctype.h> |
| 10 | #include <string.h> |
| 11 | |
| 12 | #define DEFINE_PLUG_METHOD_MACROS |
| 13 | #include "putty.h" |
| 14 | #include "network.h" |
| 15 | #include "proxy.h" |
| 16 | |
| 17 | #define do_proxy_dns(cfg) \ |
| 18 | (cfg->proxy_dns == FORCE_ON || \ |
| 19 | (cfg->proxy_dns == AUTO && cfg->proxy_type != PROXY_SOCKS)) |
| 20 | |
| 21 | /* |
| 22 | * Call this when proxy negotiation is complete, so that this |
| 23 | * socket can begin working normally. |
| 24 | */ |
| 25 | void proxy_activate (Proxy_Socket p) |
| 26 | { |
| 27 | void *data; |
| 28 | int len; |
| 29 | long output_before, output_after; |
| 30 | |
| 31 | p->state = PROXY_STATE_ACTIVE; |
| 32 | |
| 33 | /* we want to ignore new receive events until we have sent |
| 34 | * all of our buffered receive data. |
| 35 | */ |
| 36 | sk_set_frozen(p->sub_socket, 1); |
| 37 | |
| 38 | /* how many bytes of output have we buffered? */ |
| 39 | output_before = bufchain_size(&p->pending_oob_output_data) + |
| 40 | bufchain_size(&p->pending_output_data); |
| 41 | /* and keep track of how many bytes do not get sent. */ |
| 42 | output_after = 0; |
| 43 | |
| 44 | /* send buffered OOB writes */ |
| 45 | while (bufchain_size(&p->pending_oob_output_data) > 0) { |
| 46 | bufchain_prefix(&p->pending_oob_output_data, &data, &len); |
| 47 | output_after += sk_write_oob(p->sub_socket, data, len); |
| 48 | bufchain_consume(&p->pending_oob_output_data, len); |
| 49 | } |
| 50 | |
| 51 | /* send buffered normal writes */ |
| 52 | while (bufchain_size(&p->pending_output_data) > 0) { |
| 53 | bufchain_prefix(&p->pending_output_data, &data, &len); |
| 54 | output_after += sk_write(p->sub_socket, data, len); |
| 55 | bufchain_consume(&p->pending_output_data, len); |
| 56 | } |
| 57 | |
| 58 | /* if we managed to send any data, let the higher levels know. */ |
| 59 | if (output_after < output_before) |
| 60 | plug_sent(p->plug, output_after); |
| 61 | |
| 62 | /* if we were asked to flush the output during |
| 63 | * the proxy negotiation process, do so now. |
| 64 | */ |
| 65 | if (p->pending_flush) sk_flush(p->sub_socket); |
| 66 | |
| 67 | /* if the backend wanted the socket unfrozen, try to unfreeze. |
| 68 | * our set_frozen handler will flush buffered receive data before |
| 69 | * unfreezing the actual underlying socket. |
| 70 | */ |
| 71 | if (!p->freeze) |
| 72 | sk_set_frozen((Socket)p, 0); |
| 73 | } |
| 74 | |
| 75 | /* basic proxy socket functions */ |
| 76 | |
| 77 | static Plug sk_proxy_plug (Socket s, Plug p) |
| 78 | { |
| 79 | Proxy_Socket ps = (Proxy_Socket) s; |
| 80 | Plug ret = ps->plug; |
| 81 | if (p) |
| 82 | ps->plug = p; |
| 83 | return ret; |
| 84 | } |
| 85 | |
| 86 | static void sk_proxy_close (Socket s) |
| 87 | { |
| 88 | Proxy_Socket ps = (Proxy_Socket) s; |
| 89 | |
| 90 | sk_close(ps->sub_socket); |
| 91 | sfree(ps); |
| 92 | } |
| 93 | |
| 94 | static int sk_proxy_write (Socket s, const char *data, int len) |
| 95 | { |
| 96 | Proxy_Socket ps = (Proxy_Socket) s; |
| 97 | |
| 98 | if (ps->state != PROXY_STATE_ACTIVE) { |
| 99 | bufchain_add(&ps->pending_output_data, data, len); |
| 100 | return bufchain_size(&ps->pending_output_data); |
| 101 | } |
| 102 | return sk_write(ps->sub_socket, data, len); |
| 103 | } |
| 104 | |
| 105 | static int sk_proxy_write_oob (Socket s, const char *data, int len) |
| 106 | { |
| 107 | Proxy_Socket ps = (Proxy_Socket) s; |
| 108 | |
| 109 | if (ps->state != PROXY_STATE_ACTIVE) { |
| 110 | bufchain_clear(&ps->pending_output_data); |
| 111 | bufchain_clear(&ps->pending_oob_output_data); |
| 112 | bufchain_add(&ps->pending_oob_output_data, data, len); |
| 113 | return len; |
| 114 | } |
| 115 | return sk_write_oob(ps->sub_socket, data, len); |
| 116 | } |
| 117 | |
| 118 | static void sk_proxy_flush (Socket s) |
| 119 | { |
| 120 | Proxy_Socket ps = (Proxy_Socket) s; |
| 121 | |
| 122 | if (ps->state != PROXY_STATE_ACTIVE) { |
| 123 | ps->pending_flush = 1; |
| 124 | return; |
| 125 | } |
| 126 | sk_flush(ps->sub_socket); |
| 127 | } |
| 128 | |
| 129 | static void sk_proxy_set_private_ptr (Socket s, void *ptr) |
| 130 | { |
| 131 | Proxy_Socket ps = (Proxy_Socket) s; |
| 132 | sk_set_private_ptr(ps->sub_socket, ptr); |
| 133 | } |
| 134 | |
| 135 | static void * sk_proxy_get_private_ptr (Socket s) |
| 136 | { |
| 137 | Proxy_Socket ps = (Proxy_Socket) s; |
| 138 | return sk_get_private_ptr(ps->sub_socket); |
| 139 | } |
| 140 | |
| 141 | static void sk_proxy_set_frozen (Socket s, int is_frozen) |
| 142 | { |
| 143 | Proxy_Socket ps = (Proxy_Socket) s; |
| 144 | |
| 145 | if (ps->state != PROXY_STATE_ACTIVE) { |
| 146 | ps->freeze = is_frozen; |
| 147 | return; |
| 148 | } |
| 149 | |
| 150 | /* handle any remaining buffered recv data first */ |
| 151 | if (bufchain_size(&ps->pending_input_data) > 0) { |
| 152 | ps->freeze = is_frozen; |
| 153 | |
| 154 | /* loop while we still have buffered data, and while we are |
| 155 | * unfrozen. the plug_receive call in the loop could result |
| 156 | * in a call back into this function refreezing the socket, |
| 157 | * so we have to check each time. |
| 158 | */ |
| 159 | while (!ps->freeze && bufchain_size(&ps->pending_input_data) > 0) { |
| 160 | void *data; |
| 161 | int len; |
| 162 | bufchain_prefix(&ps->pending_input_data, &data, &len); |
| 163 | plug_receive(ps->plug, 0, data, len); |
| 164 | bufchain_consume(&ps->pending_input_data, len); |
| 165 | } |
| 166 | |
| 167 | /* if we're still frozen, we'll have to wait for another |
| 168 | * call from the backend to finish unbuffering the data. |
| 169 | */ |
| 170 | if (ps->freeze) return; |
| 171 | } |
| 172 | |
| 173 | sk_set_frozen(ps->sub_socket, is_frozen); |
| 174 | } |
| 175 | |
| 176 | static char * sk_proxy_socket_error (Socket s) |
| 177 | { |
| 178 | Proxy_Socket ps = (Proxy_Socket) s; |
| 179 | if (ps->error != NULL || ps->sub_socket == NULL) { |
| 180 | return ps->error; |
| 181 | } |
| 182 | return sk_socket_error(ps->sub_socket); |
| 183 | } |
| 184 | |
| 185 | /* basic proxy plug functions */ |
| 186 | |
| 187 | static int plug_proxy_closing (Plug p, char *error_msg, |
| 188 | int error_code, int calling_back) |
| 189 | { |
| 190 | Proxy_Plug pp = (Proxy_Plug) p; |
| 191 | Proxy_Socket ps = pp->proxy_socket; |
| 192 | |
| 193 | if (ps->state != PROXY_STATE_ACTIVE) { |
| 194 | ps->closing_error_msg = error_msg; |
| 195 | ps->closing_error_code = error_code; |
| 196 | ps->closing_calling_back = calling_back; |
| 197 | return ps->negotiate(ps, PROXY_CHANGE_CLOSING); |
| 198 | } |
| 199 | return plug_closing(ps->plug, error_msg, |
| 200 | error_code, calling_back); |
| 201 | } |
| 202 | |
| 203 | static int plug_proxy_receive (Plug p, int urgent, char *data, int len) |
| 204 | { |
| 205 | Proxy_Plug pp = (Proxy_Plug) p; |
| 206 | Proxy_Socket ps = pp->proxy_socket; |
| 207 | |
| 208 | if (ps->state != PROXY_STATE_ACTIVE) { |
| 209 | /* we will lose the urgentness of this data, but since most, |
| 210 | * if not all, of this data will be consumed by the negotiation |
| 211 | * process, hopefully it won't affect the protocol above us |
| 212 | */ |
| 213 | bufchain_add(&ps->pending_input_data, data, len); |
| 214 | ps->receive_urgent = urgent; |
| 215 | ps->receive_data = data; |
| 216 | ps->receive_len = len; |
| 217 | return ps->negotiate(ps, PROXY_CHANGE_RECEIVE); |
| 218 | } |
| 219 | return plug_receive(ps->plug, urgent, data, len); |
| 220 | } |
| 221 | |
| 222 | static void plug_proxy_sent (Plug p, int bufsize) |
| 223 | { |
| 224 | Proxy_Plug pp = (Proxy_Plug) p; |
| 225 | Proxy_Socket ps = pp->proxy_socket; |
| 226 | |
| 227 | if (ps->state != PROXY_STATE_ACTIVE) { |
| 228 | ps->sent_bufsize = bufsize; |
| 229 | ps->negotiate(ps, PROXY_CHANGE_SENT); |
| 230 | return; |
| 231 | } |
| 232 | plug_sent(ps->plug, bufsize); |
| 233 | } |
| 234 | |
| 235 | static int plug_proxy_accepting (Plug p, void *sock) |
| 236 | { |
| 237 | Proxy_Plug pp = (Proxy_Plug) p; |
| 238 | Proxy_Socket ps = pp->proxy_socket; |
| 239 | |
| 240 | if (ps->state != PROXY_STATE_ACTIVE) { |
| 241 | ps->accepting_sock = sock; |
| 242 | return ps->negotiate(ps, PROXY_CHANGE_ACCEPTING); |
| 243 | } |
| 244 | return plug_accepting(ps->plug, sock); |
| 245 | } |
| 246 | |
| 247 | /* |
| 248 | * This function can accept a NULL pointer as `addr', in which case |
| 249 | * it will only check the host name. |
| 250 | */ |
| 251 | static int proxy_for_destination (SockAddr addr, char *hostname, int port, |
| 252 | const Config *cfg) |
| 253 | { |
| 254 | int s = 0, e = 0; |
| 255 | char hostip[64]; |
| 256 | int hostip_len, hostname_len; |
| 257 | const char *exclude_list; |
| 258 | |
| 259 | /* |
| 260 | * Check the host name and IP against the hard-coded |
| 261 | * representations of `localhost'. |
| 262 | */ |
| 263 | if (!cfg->even_proxy_localhost && |
| 264 | (sk_hostname_is_local(hostname) || |
| 265 | (addr && sk_address_is_local(addr)))) |
| 266 | return 0; /* do not proxy */ |
| 267 | |
| 268 | /* we want a string representation of the IP address for comparisons */ |
| 269 | if (addr) { |
| 270 | sk_getaddr(addr, hostip, 64); |
| 271 | hostip_len = strlen(hostip); |
| 272 | } else |
| 273 | hostip_len = 0; /* placate gcc; shouldn't be required */ |
| 274 | |
| 275 | hostname_len = strlen(hostname); |
| 276 | |
| 277 | exclude_list = cfg->proxy_exclude_list; |
| 278 | |
| 279 | /* now parse the exclude list, and see if either our IP |
| 280 | * or hostname matches anything in it. |
| 281 | */ |
| 282 | |
| 283 | while (exclude_list[s]) { |
| 284 | while (exclude_list[s] && |
| 285 | (isspace((unsigned char)exclude_list[s]) || |
| 286 | exclude_list[s] == ',')) s++; |
| 287 | |
| 288 | if (!exclude_list[s]) break; |
| 289 | |
| 290 | e = s; |
| 291 | |
| 292 | while (exclude_list[e] && |
| 293 | (isalnum((unsigned char)exclude_list[e]) || |
| 294 | exclude_list[e] == '-' || |
| 295 | exclude_list[e] == '.' || |
| 296 | exclude_list[e] == '*')) e++; |
| 297 | |
| 298 | if (exclude_list[s] == '*') { |
| 299 | /* wildcard at beginning of entry */ |
| 300 | |
| 301 | if ((addr && strnicmp(hostip + hostip_len - (e - s - 1), |
| 302 | exclude_list + s + 1, e - s - 1) == 0) || |
| 303 | strnicmp(hostname + hostname_len - (e - s - 1), |
| 304 | exclude_list + s + 1, e - s - 1) == 0) |
| 305 | return 0; /* IP/hostname range excluded. do not use proxy. */ |
| 306 | |
| 307 | } else if (exclude_list[e-1] == '*') { |
| 308 | /* wildcard at end of entry */ |
| 309 | |
| 310 | if ((addr && strnicmp(hostip, exclude_list + s, e - s - 1) == 0) || |
| 311 | strnicmp(hostname, exclude_list + s, e - s - 1) == 0) |
| 312 | return 0; /* IP/hostname range excluded. do not use proxy. */ |
| 313 | |
| 314 | } else { |
| 315 | /* no wildcard at either end, so let's try an absolute |
| 316 | * match (ie. a specific IP) |
| 317 | */ |
| 318 | |
| 319 | if (addr && stricmp(hostip, exclude_list + s) == 0) |
| 320 | return 0; /* IP/hostname excluded. do not use proxy. */ |
| 321 | if (stricmp(hostname, exclude_list + s) == 0) |
| 322 | return 0; /* IP/hostname excluded. do not use proxy. */ |
| 323 | } |
| 324 | |
| 325 | s = e; |
| 326 | |
| 327 | /* Make sure we really have reached the next comma or end-of-string */ |
| 328 | while (exclude_list[s] && |
| 329 | !isspace((unsigned char)exclude_list[s]) && |
| 330 | exclude_list[s] != ',') s++; |
| 331 | } |
| 332 | |
| 333 | /* no matches in the exclude list, so use the proxy */ |
| 334 | return 1; |
| 335 | } |
| 336 | |
| 337 | SockAddr name_lookup(char *host, int port, char **canonicalname, |
| 338 | const Config *cfg) |
| 339 | { |
| 340 | if (cfg->proxy_type != PROXY_NONE && |
| 341 | do_proxy_dns(cfg) && |
| 342 | proxy_for_destination(NULL, host, port, cfg)) { |
| 343 | *canonicalname = dupstr(host); |
| 344 | return sk_nonamelookup(host); |
| 345 | } |
| 346 | |
| 347 | return sk_namelookup(host, canonicalname); |
| 348 | } |
| 349 | |
| 350 | Socket new_connection(SockAddr addr, char *hostname, |
| 351 | int port, int privport, |
| 352 | int oobinline, int nodelay, Plug plug, |
| 353 | const Config *cfg) |
| 354 | { |
| 355 | static const struct socket_function_table socket_fn_table = { |
| 356 | sk_proxy_plug, |
| 357 | sk_proxy_close, |
| 358 | sk_proxy_write, |
| 359 | sk_proxy_write_oob, |
| 360 | sk_proxy_flush, |
| 361 | sk_proxy_set_private_ptr, |
| 362 | sk_proxy_get_private_ptr, |
| 363 | sk_proxy_set_frozen, |
| 364 | sk_proxy_socket_error |
| 365 | }; |
| 366 | |
| 367 | static const struct plug_function_table plug_fn_table = { |
| 368 | plug_proxy_closing, |
| 369 | plug_proxy_receive, |
| 370 | plug_proxy_sent, |
| 371 | plug_proxy_accepting |
| 372 | }; |
| 373 | |
| 374 | if (cfg->proxy_type != PROXY_NONE && |
| 375 | proxy_for_destination(addr, hostname, port, cfg)) |
| 376 | { |
| 377 | Proxy_Socket ret; |
| 378 | Proxy_Plug pplug; |
| 379 | SockAddr proxy_addr; |
| 380 | char *proxy_canonical_name, *err; |
| 381 | |
| 382 | ret = snew(struct Socket_proxy_tag); |
| 383 | ret->fn = &socket_fn_table; |
| 384 | ret->cfg = *cfg; /* STRUCTURE COPY */ |
| 385 | ret->plug = plug; |
| 386 | ret->remote_addr = addr; |
| 387 | ret->remote_port = port; |
| 388 | |
| 389 | ret->error = NULL; |
| 390 | ret->pending_flush = 0; |
| 391 | ret->freeze = 0; |
| 392 | |
| 393 | bufchain_init(&ret->pending_input_data); |
| 394 | bufchain_init(&ret->pending_output_data); |
| 395 | bufchain_init(&ret->pending_oob_output_data); |
| 396 | |
| 397 | ret->sub_socket = NULL; |
| 398 | ret->state = PROXY_STATE_NEW; |
| 399 | ret->negotiate = NULL; |
| 400 | |
| 401 | if (cfg->proxy_type == PROXY_HTTP) { |
| 402 | ret->negotiate = proxy_http_negotiate; |
| 403 | } else if (cfg->proxy_type == PROXY_SOCKS) { |
| 404 | if (cfg->proxy_socks_version == 4) |
| 405 | ret->negotiate = proxy_socks4_negotiate; |
| 406 | else |
| 407 | ret->negotiate = proxy_socks5_negotiate; |
| 408 | } else if (cfg->proxy_type == PROXY_TELNET) { |
| 409 | ret->negotiate = proxy_telnet_negotiate; |
| 410 | } else { |
| 411 | ret->error = "Proxy error: Unknown proxy method"; |
| 412 | return (Socket) ret; |
| 413 | } |
| 414 | |
| 415 | /* create the proxy plug to map calls from the actual |
| 416 | * socket into our proxy socket layer */ |
| 417 | pplug = snew(struct Plug_proxy_tag); |
| 418 | pplug->fn = &plug_fn_table; |
| 419 | pplug->proxy_socket = ret; |
| 420 | |
| 421 | /* look-up proxy */ |
| 422 | proxy_addr = sk_namelookup(cfg->proxy_host, |
| 423 | &proxy_canonical_name); |
| 424 | if ((err = sk_addr_error(proxy_addr)) != NULL) { |
| 425 | ret->error = "Proxy error: Unable to resolve proxy host name"; |
| 426 | return (Socket)ret; |
| 427 | } |
| 428 | sfree(proxy_canonical_name); |
| 429 | |
| 430 | /* create the actual socket we will be using, |
| 431 | * connected to our proxy server and port. |
| 432 | */ |
| 433 | ret->sub_socket = sk_new(proxy_addr, cfg->proxy_port, |
| 434 | privport, oobinline, |
| 435 | nodelay, (Plug) pplug); |
| 436 | if (sk_socket_error(ret->sub_socket) != NULL) |
| 437 | return (Socket) ret; |
| 438 | |
| 439 | sk_addr_free(proxy_addr); |
| 440 | |
| 441 | /* start the proxy negotiation process... */ |
| 442 | sk_set_frozen(ret->sub_socket, 0); |
| 443 | ret->negotiate(ret, PROXY_CHANGE_NEW); |
| 444 | |
| 445 | return (Socket) ret; |
| 446 | } |
| 447 | |
| 448 | /* no proxy, so just return the direct socket */ |
| 449 | return sk_new(addr, port, privport, oobinline, nodelay, plug); |
| 450 | } |
| 451 | |
| 452 | Socket new_listener(char *srcaddr, int port, Plug plug, int local_host_only, |
| 453 | const Config *cfg) |
| 454 | { |
| 455 | /* TODO: SOCKS (and potentially others) support inbound |
| 456 | * TODO: connections via the proxy. support them. |
| 457 | */ |
| 458 | |
| 459 | return sk_newlistener(srcaddr, port, plug, local_host_only); |
| 460 | } |
| 461 | |
| 462 | /* ---------------------------------------------------------------------- |
| 463 | * HTTP CONNECT proxy type. |
| 464 | */ |
| 465 | |
| 466 | static int get_line_end (char * data, int len) |
| 467 | { |
| 468 | int off = 0; |
| 469 | |
| 470 | while (off < len) |
| 471 | { |
| 472 | if (data[off] == '\n') { |
| 473 | /* we have a newline */ |
| 474 | off++; |
| 475 | |
| 476 | /* is that the only thing on this line? */ |
| 477 | if (off <= 2) return off; |
| 478 | |
| 479 | /* if not, then there is the possibility that this header |
| 480 | * continues onto the next line, if it starts with a space |
| 481 | * or a tab. |
| 482 | */ |
| 483 | |
| 484 | if (off + 1 < len && |
| 485 | data[off+1] != ' ' && |
| 486 | data[off+1] != '\t') return off; |
| 487 | |
| 488 | /* the line does continue, so we have to keep going |
| 489 | * until we see an the header's "real" end of line. |
| 490 | */ |
| 491 | off++; |
| 492 | } |
| 493 | |
| 494 | off++; |
| 495 | } |
| 496 | |
| 497 | return -1; |
| 498 | } |
| 499 | |
| 500 | int proxy_http_negotiate (Proxy_Socket p, int change) |
| 501 | { |
| 502 | if (p->state == PROXY_STATE_NEW) { |
| 503 | /* we are just beginning the proxy negotiate process, |
| 504 | * so we'll send off the initial bits of the request. |
| 505 | * for this proxy method, it's just a simple HTTP |
| 506 | * request |
| 507 | */ |
| 508 | char *buf, dest[512]; |
| 509 | |
| 510 | sk_getaddr(p->remote_addr, dest, lenof(dest)); |
| 511 | |
| 512 | buf = dupprintf("CONNECT %s:%i HTTP/1.1\r\nHost: %s:%i\r\n", |
| 513 | dest, p->remote_port, dest, p->remote_port); |
| 514 | sk_write(p->sub_socket, buf, strlen(buf)); |
| 515 | sfree(buf); |
| 516 | |
| 517 | if (p->cfg.proxy_username[0] || p->cfg.proxy_password[0]) { |
| 518 | char buf[sizeof(p->cfg.proxy_username)+sizeof(p->cfg.proxy_password)]; |
| 519 | char buf2[sizeof(buf)*4/3 + 100]; |
| 520 | int i, j, len; |
| 521 | sprintf(buf, "%s:%s", p->cfg.proxy_username, p->cfg.proxy_password); |
| 522 | len = strlen(buf); |
| 523 | sprintf(buf2, "Proxy-Authorization: Basic "); |
| 524 | for (i = 0, j = strlen(buf2); i < len; i += 3, j += 4) |
| 525 | base64_encode_atom((unsigned char *)(buf+i), |
| 526 | (len-i > 3 ? 3 : len-i), buf2+j); |
| 527 | strcpy(buf2+j, "\r\n"); |
| 528 | sk_write(p->sub_socket, buf2, strlen(buf2)); |
| 529 | } |
| 530 | |
| 531 | sk_write(p->sub_socket, "\r\n", 2); |
| 532 | |
| 533 | p->state = 1; |
| 534 | return 0; |
| 535 | } |
| 536 | |
| 537 | if (change == PROXY_CHANGE_CLOSING) { |
| 538 | /* if our proxy negotiation process involves closing and opening |
| 539 | * new sockets, then we would want to intercept this closing |
| 540 | * callback when we were expecting it. if we aren't anticipating |
| 541 | * a socket close, then some error must have occurred. we'll |
| 542 | * just pass those errors up to the backend. |
| 543 | */ |
| 544 | return plug_closing(p->plug, p->closing_error_msg, |
| 545 | p->closing_error_code, |
| 546 | p->closing_calling_back); |
| 547 | } |
| 548 | |
| 549 | if (change == PROXY_CHANGE_SENT) { |
| 550 | /* some (or all) of what we wrote to the proxy was sent. |
| 551 | * we don't do anything new, however, until we receive the |
| 552 | * proxy's response. we might want to set a timer so we can |
| 553 | * timeout the proxy negotiation after a while... |
| 554 | */ |
| 555 | return 0; |
| 556 | } |
| 557 | |
| 558 | if (change == PROXY_CHANGE_ACCEPTING) { |
| 559 | /* we should _never_ see this, as we are using our socket to |
| 560 | * connect to a proxy, not accepting inbound connections. |
| 561 | * what should we do? close the socket with an appropriate |
| 562 | * error message? |
| 563 | */ |
| 564 | return plug_accepting(p->plug, p->accepting_sock); |
| 565 | } |
| 566 | |
| 567 | if (change == PROXY_CHANGE_RECEIVE) { |
| 568 | /* we have received data from the underlying socket, which |
| 569 | * we'll need to parse, process, and respond to appropriately. |
| 570 | */ |
| 571 | |
| 572 | char *data, *datap; |
| 573 | int len; |
| 574 | int eol; |
| 575 | |
| 576 | if (p->state == 1) { |
| 577 | |
| 578 | int min_ver, maj_ver, status; |
| 579 | |
| 580 | /* get the status line */ |
| 581 | len = bufchain_size(&p->pending_input_data); |
| 582 | assert(len > 0); /* or we wouldn't be here */ |
| 583 | data = snewn(len, char); |
| 584 | bufchain_fetch(&p->pending_input_data, data, len); |
| 585 | |
| 586 | eol = get_line_end(data, len); |
| 587 | if (eol < 0) { |
| 588 | sfree(data); |
| 589 | return 1; |
| 590 | } |
| 591 | |
| 592 | status = -1; |
| 593 | /* We can't rely on whether the %n incremented the sscanf return */ |
| 594 | if (sscanf((char *)data, "HTTP/%i.%i %n", |
| 595 | &maj_ver, &min_ver, &status) < 2 || status == -1) { |
| 596 | plug_closing(p->plug, "Proxy error: HTTP response was absent", |
| 597 | PROXY_ERROR_GENERAL, 0); |
| 598 | sfree(data); |
| 599 | return 1; |
| 600 | } |
| 601 | |
| 602 | /* remove the status line from the input buffer. */ |
| 603 | bufchain_consume(&p->pending_input_data, eol); |
| 604 | if (data[status] != '2') { |
| 605 | /* error */ |
| 606 | char *buf; |
| 607 | data[eol] = '\0'; |
| 608 | while (eol > status && |
| 609 | (data[eol-1] == '\r' || data[eol-1] == '\n')) |
| 610 | data[--eol] = '\0'; |
| 611 | buf = dupprintf("Proxy error: %s", data+status); |
| 612 | plug_closing(p->plug, buf, PROXY_ERROR_GENERAL, 0); |
| 613 | sfree(buf); |
| 614 | sfree(data); |
| 615 | return 1; |
| 616 | } |
| 617 | |
| 618 | sfree(data); |
| 619 | |
| 620 | p->state = 2; |
| 621 | } |
| 622 | |
| 623 | if (p->state == 2) { |
| 624 | |
| 625 | /* get headers. we're done when we get a |
| 626 | * header of length 2, (ie. just "\r\n") |
| 627 | */ |
| 628 | |
| 629 | len = bufchain_size(&p->pending_input_data); |
| 630 | assert(len > 0); /* or we wouldn't be here */ |
| 631 | data = snewn(len, char); |
| 632 | datap = data; |
| 633 | bufchain_fetch(&p->pending_input_data, data, len); |
| 634 | |
| 635 | eol = get_line_end(datap, len); |
| 636 | if (eol < 0) { |
| 637 | sfree(data); |
| 638 | return 1; |
| 639 | } |
| 640 | while (eol > 2) |
| 641 | { |
| 642 | bufchain_consume(&p->pending_input_data, eol); |
| 643 | datap += eol; |
| 644 | len -= eol; |
| 645 | eol = get_line_end(datap, len); |
| 646 | } |
| 647 | |
| 648 | if (eol == 2) { |
| 649 | /* we're done */ |
| 650 | bufchain_consume(&p->pending_input_data, 2); |
| 651 | proxy_activate(p); |
| 652 | /* proxy activate will have dealt with |
| 653 | * whatever is left of the buffer */ |
| 654 | sfree(data); |
| 655 | return 1; |
| 656 | } |
| 657 | |
| 658 | sfree(data); |
| 659 | return 1; |
| 660 | } |
| 661 | } |
| 662 | |
| 663 | plug_closing(p->plug, "Proxy error: unexpected proxy error", |
| 664 | PROXY_ERROR_UNEXPECTED, 0); |
| 665 | return 1; |
| 666 | } |
| 667 | |
| 668 | /* ---------------------------------------------------------------------- |
| 669 | * SOCKS proxy type. |
| 670 | */ |
| 671 | |
| 672 | /* SOCKS version 4 */ |
| 673 | int proxy_socks4_negotiate (Proxy_Socket p, int change) |
| 674 | { |
| 675 | if (p->state == PROXY_CHANGE_NEW) { |
| 676 | |
| 677 | /* request format: |
| 678 | * version number (1 byte) = 4 |
| 679 | * command code (1 byte) |
| 680 | * 1 = CONNECT |
| 681 | * 2 = BIND |
| 682 | * dest. port (2 bytes) [network order] |
| 683 | * dest. address (4 bytes) |
| 684 | * user ID (variable length, null terminated string) |
| 685 | */ |
| 686 | |
| 687 | int length, type, namelen; |
| 688 | char *command, addr[4], hostname[512]; |
| 689 | |
| 690 | type = sk_addrtype(p->remote_addr); |
| 691 | if (type == ADDRTYPE_IPV6) { |
| 692 | plug_closing(p->plug, "Proxy error: SOCKS version 4 does" |
| 693 | " not support IPv6", PROXY_ERROR_GENERAL, 0); |
| 694 | return 1; |
| 695 | } else if (type == ADDRTYPE_IPV4) { |
| 696 | namelen = 0; |
| 697 | sk_addrcopy(p->remote_addr, addr); |
| 698 | } else { /* type == ADDRTYPE_NAME */ |
| 699 | assert(type == ADDRTYPE_NAME); |
| 700 | sk_getaddr(p->remote_addr, hostname, lenof(hostname)); |
| 701 | namelen = strlen(hostname) + 1; /* include the NUL */ |
| 702 | addr[0] = addr[1] = addr[2] = 0; |
| 703 | addr[3] = 1; |
| 704 | } |
| 705 | |
| 706 | length = strlen(p->cfg.proxy_username) + namelen + 9; |
| 707 | command = snewn(length, char); |
| 708 | strcpy(command + 8, p->cfg.proxy_username); |
| 709 | |
| 710 | command[0] = 4; /* version 4 */ |
| 711 | command[1] = 1; /* CONNECT command */ |
| 712 | |
| 713 | /* port */ |
| 714 | command[2] = (char) (p->remote_port >> 8) & 0xff; |
| 715 | command[3] = (char) p->remote_port & 0xff; |
| 716 | |
| 717 | /* address */ |
| 718 | memcpy(command + 4, addr, 4); |
| 719 | |
| 720 | /* hostname */ |
| 721 | memcpy(command + 8 + strlen(p->cfg.proxy_username) + 1, |
| 722 | hostname, namelen); |
| 723 | |
| 724 | sk_write(p->sub_socket, command, length); |
| 725 | sfree(command); |
| 726 | |
| 727 | p->state = 1; |
| 728 | return 0; |
| 729 | } |
| 730 | |
| 731 | if (change == PROXY_CHANGE_CLOSING) { |
| 732 | /* if our proxy negotiation process involves closing and opening |
| 733 | * new sockets, then we would want to intercept this closing |
| 734 | * callback when we were expecting it. if we aren't anticipating |
| 735 | * a socket close, then some error must have occurred. we'll |
| 736 | * just pass those errors up to the backend. |
| 737 | */ |
| 738 | return plug_closing(p->plug, p->closing_error_msg, |
| 739 | p->closing_error_code, |
| 740 | p->closing_calling_back); |
| 741 | } |
| 742 | |
| 743 | if (change == PROXY_CHANGE_SENT) { |
| 744 | /* some (or all) of what we wrote to the proxy was sent. |
| 745 | * we don't do anything new, however, until we receive the |
| 746 | * proxy's response. we might want to set a timer so we can |
| 747 | * timeout the proxy negotiation after a while... |
| 748 | */ |
| 749 | return 0; |
| 750 | } |
| 751 | |
| 752 | if (change == PROXY_CHANGE_ACCEPTING) { |
| 753 | /* we should _never_ see this, as we are using our socket to |
| 754 | * connect to a proxy, not accepting inbound connections. |
| 755 | * what should we do? close the socket with an appropriate |
| 756 | * error message? |
| 757 | */ |
| 758 | return plug_accepting(p->plug, p->accepting_sock); |
| 759 | } |
| 760 | |
| 761 | if (change == PROXY_CHANGE_RECEIVE) { |
| 762 | /* we have received data from the underlying socket, which |
| 763 | * we'll need to parse, process, and respond to appropriately. |
| 764 | */ |
| 765 | |
| 766 | if (p->state == 1) { |
| 767 | /* response format: |
| 768 | * version number (1 byte) = 4 |
| 769 | * reply code (1 byte) |
| 770 | * 90 = request granted |
| 771 | * 91 = request rejected or failed |
| 772 | * 92 = request rejected due to lack of IDENTD on client |
| 773 | * 93 = request rejected due to difference in user ID |
| 774 | * (what we sent vs. what IDENTD said) |
| 775 | * dest. port (2 bytes) |
| 776 | * dest. address (4 bytes) |
| 777 | */ |
| 778 | |
| 779 | char data[8]; |
| 780 | |
| 781 | if (bufchain_size(&p->pending_input_data) < 8) |
| 782 | return 1; /* not got anything yet */ |
| 783 | |
| 784 | /* get the response */ |
| 785 | bufchain_fetch(&p->pending_input_data, data, 8); |
| 786 | |
| 787 | if (data[0] != 0) { |
| 788 | plug_closing(p->plug, "Proxy error: SOCKS proxy responded with " |
| 789 | "unexpected reply code version", |
| 790 | PROXY_ERROR_GENERAL, 0); |
| 791 | return 1; |
| 792 | } |
| 793 | |
| 794 | if (data[1] != 90) { |
| 795 | |
| 796 | switch (data[1]) { |
| 797 | case 92: |
| 798 | plug_closing(p->plug, "Proxy error: SOCKS server wanted IDENTD on client", |
| 799 | PROXY_ERROR_GENERAL, 0); |
| 800 | break; |
| 801 | case 93: |
| 802 | plug_closing(p->plug, "Proxy error: Username and IDENTD on client don't agree", |
| 803 | PROXY_ERROR_GENERAL, 0); |
| 804 | break; |
| 805 | case 91: |
| 806 | default: |
| 807 | plug_closing(p->plug, "Proxy error: Error while communicating with proxy", |
| 808 | PROXY_ERROR_GENERAL, 0); |
| 809 | break; |
| 810 | } |
| 811 | |
| 812 | return 1; |
| 813 | } |
| 814 | bufchain_consume(&p->pending_input_data, 8); |
| 815 | |
| 816 | /* we're done */ |
| 817 | proxy_activate(p); |
| 818 | /* proxy activate will have dealt with |
| 819 | * whatever is left of the buffer */ |
| 820 | return 1; |
| 821 | } |
| 822 | } |
| 823 | |
| 824 | plug_closing(p->plug, "Proxy error: unexpected proxy error", |
| 825 | PROXY_ERROR_UNEXPECTED, 0); |
| 826 | return 1; |
| 827 | } |
| 828 | |
| 829 | /* SOCKS version 5 */ |
| 830 | int proxy_socks5_negotiate (Proxy_Socket p, int change) |
| 831 | { |
| 832 | if (p->state == PROXY_CHANGE_NEW) { |
| 833 | |
| 834 | /* initial command: |
| 835 | * version number (1 byte) = 5 |
| 836 | * number of available authentication methods (1 byte) |
| 837 | * available authentication methods (1 byte * previous value) |
| 838 | * authentication methods: |
| 839 | * 0x00 = no authentication |
| 840 | * 0x01 = GSSAPI |
| 841 | * 0x02 = username/password |
| 842 | * 0x03 = CHAP |
| 843 | */ |
| 844 | |
| 845 | char command[4]; |
| 846 | int len; |
| 847 | |
| 848 | command[0] = 5; /* version 5 */ |
| 849 | if (p->cfg.proxy_username[0] || p->cfg.proxy_password[0]) { |
| 850 | command[1] = 2; /* two methods supported: */ |
| 851 | command[2] = 0x00; /* no authentication */ |
| 852 | command[3] = 0x02; /* username/password */ |
| 853 | len = 4; |
| 854 | } else { |
| 855 | command[1] = 1; /* one methods supported: */ |
| 856 | command[2] = 0x00; /* no authentication */ |
| 857 | len = 3; |
| 858 | } |
| 859 | |
| 860 | sk_write(p->sub_socket, command, len); |
| 861 | |
| 862 | p->state = 1; |
| 863 | return 0; |
| 864 | } |
| 865 | |
| 866 | if (change == PROXY_CHANGE_CLOSING) { |
| 867 | /* if our proxy negotiation process involves closing and opening |
| 868 | * new sockets, then we would want to intercept this closing |
| 869 | * callback when we were expecting it. if we aren't anticipating |
| 870 | * a socket close, then some error must have occurred. we'll |
| 871 | * just pass those errors up to the backend. |
| 872 | */ |
| 873 | return plug_closing(p->plug, p->closing_error_msg, |
| 874 | p->closing_error_code, |
| 875 | p->closing_calling_back); |
| 876 | } |
| 877 | |
| 878 | if (change == PROXY_CHANGE_SENT) { |
| 879 | /* some (or all) of what we wrote to the proxy was sent. |
| 880 | * we don't do anything new, however, until we receive the |
| 881 | * proxy's response. we might want to set a timer so we can |
| 882 | * timeout the proxy negotiation after a while... |
| 883 | */ |
| 884 | return 0; |
| 885 | } |
| 886 | |
| 887 | if (change == PROXY_CHANGE_ACCEPTING) { |
| 888 | /* we should _never_ see this, as we are using our socket to |
| 889 | * connect to a proxy, not accepting inbound connections. |
| 890 | * what should we do? close the socket with an appropriate |
| 891 | * error message? |
| 892 | */ |
| 893 | return plug_accepting(p->plug, p->accepting_sock); |
| 894 | } |
| 895 | |
| 896 | if (change == PROXY_CHANGE_RECEIVE) { |
| 897 | /* we have received data from the underlying socket, which |
| 898 | * we'll need to parse, process, and respond to appropriately. |
| 899 | */ |
| 900 | |
| 901 | if (p->state == 1) { |
| 902 | |
| 903 | /* initial response: |
| 904 | * version number (1 byte) = 5 |
| 905 | * authentication method (1 byte) |
| 906 | * authentication methods: |
| 907 | * 0x00 = no authentication |
| 908 | * 0x01 = GSSAPI |
| 909 | * 0x02 = username/password |
| 910 | * 0x03 = CHAP |
| 911 | * 0xff = no acceptable methods |
| 912 | */ |
| 913 | char data[2]; |
| 914 | |
| 915 | if (bufchain_size(&p->pending_input_data) < 2) |
| 916 | return 1; /* not got anything yet */ |
| 917 | |
| 918 | /* get the response */ |
| 919 | bufchain_fetch(&p->pending_input_data, data, 2); |
| 920 | |
| 921 | if (data[0] != 5) { |
| 922 | plug_closing(p->plug, "Proxy error: SOCKS proxy returned unexpected version", |
| 923 | PROXY_ERROR_GENERAL, 0); |
| 924 | return 1; |
| 925 | } |
| 926 | |
| 927 | if (data[1] == 0x00) p->state = 2; /* no authentication needed */ |
| 928 | else if (data[1] == 0x01) p->state = 4; /* GSSAPI authentication */ |
| 929 | else if (data[1] == 0x02) p->state = 5; /* username/password authentication */ |
| 930 | else if (data[1] == 0x03) p->state = 6; /* CHAP authentication */ |
| 931 | else { |
| 932 | plug_closing(p->plug, "Proxy error: SOCKS proxy did not accept our authentication", |
| 933 | PROXY_ERROR_GENERAL, 0); |
| 934 | return 1; |
| 935 | } |
| 936 | bufchain_consume(&p->pending_input_data, 2); |
| 937 | } |
| 938 | |
| 939 | if (p->state == 7) { |
| 940 | |
| 941 | /* password authentication reply format: |
| 942 | * version number (1 bytes) = 1 |
| 943 | * reply code (1 byte) |
| 944 | * 0 = succeeded |
| 945 | * >0 = failed |
| 946 | */ |
| 947 | char data[2]; |
| 948 | |
| 949 | if (bufchain_size(&p->pending_input_data) < 2) |
| 950 | return 1; /* not got anything yet */ |
| 951 | |
| 952 | /* get the response */ |
| 953 | bufchain_fetch(&p->pending_input_data, data, 2); |
| 954 | |
| 955 | if (data[0] != 1) { |
| 956 | plug_closing(p->plug, "Proxy error: SOCKS password " |
| 957 | "subnegotiation contained wrong version number", |
| 958 | PROXY_ERROR_GENERAL, 0); |
| 959 | return 1; |
| 960 | } |
| 961 | |
| 962 | if (data[1] != 0) { |
| 963 | |
| 964 | plug_closing(p->plug, "Proxy error: SOCKS proxy refused" |
| 965 | " password authentication", |
| 966 | PROXY_ERROR_GENERAL, 0); |
| 967 | return 1; |
| 968 | } |
| 969 | |
| 970 | bufchain_consume(&p->pending_input_data, 2); |
| 971 | p->state = 2; /* now proceed as authenticated */ |
| 972 | } |
| 973 | |
| 974 | if (p->state == 2) { |
| 975 | |
| 976 | /* request format: |
| 977 | * version number (1 byte) = 5 |
| 978 | * command code (1 byte) |
| 979 | * 1 = CONNECT |
| 980 | * 2 = BIND |
| 981 | * 3 = UDP ASSOCIATE |
| 982 | * reserved (1 byte) = 0x00 |
| 983 | * address type (1 byte) |
| 984 | * 1 = IPv4 |
| 985 | * 3 = domainname (first byte has length, no terminating null) |
| 986 | * 4 = IPv6 |
| 987 | * dest. address (variable) |
| 988 | * dest. port (2 bytes) [network order] |
| 989 | */ |
| 990 | |
| 991 | char command[512]; |
| 992 | int len; |
| 993 | int type; |
| 994 | |
| 995 | type = sk_addrtype(p->remote_addr); |
| 996 | if (type == ADDRTYPE_IPV4) { |
| 997 | len = 10; /* 4 hdr + 4 addr + 2 trailer */ |
| 998 | command[3] = 1; /* IPv4 */ |
| 999 | sk_addrcopy(p->remote_addr, command+4); |
| 1000 | } else if (type == ADDRTYPE_IPV6) { |
| 1001 | len = 22; /* 4 hdr + 16 addr + 2 trailer */ |
| 1002 | command[3] = 4; /* IPv6 */ |
| 1003 | sk_addrcopy(p->remote_addr, command+4); |
| 1004 | } else { |
| 1005 | assert(type == ADDRTYPE_NAME); |
| 1006 | command[3] = 3; |
| 1007 | sk_getaddr(p->remote_addr, command+5, 256); |
| 1008 | command[4] = strlen(command+5); |
| 1009 | len = 7 + command[4]; /* 4 hdr, 1 len, N addr, 2 trailer */ |
| 1010 | } |
| 1011 | |
| 1012 | command[0] = 5; /* version 5 */ |
| 1013 | command[1] = 1; /* CONNECT command */ |
| 1014 | command[2] = 0x00; |
| 1015 | |
| 1016 | /* port */ |
| 1017 | command[len-2] = (char) (p->remote_port >> 8) & 0xff; |
| 1018 | command[len-1] = (char) p->remote_port & 0xff; |
| 1019 | |
| 1020 | sk_write(p->sub_socket, command, len); |
| 1021 | |
| 1022 | p->state = 3; |
| 1023 | return 1; |
| 1024 | } |
| 1025 | |
| 1026 | if (p->state == 3) { |
| 1027 | |
| 1028 | /* reply format: |
| 1029 | * version number (1 bytes) = 5 |
| 1030 | * reply code (1 byte) |
| 1031 | * 0 = succeeded |
| 1032 | * 1 = general SOCKS server failure |
| 1033 | * 2 = connection not allowed by ruleset |
| 1034 | * 3 = network unreachable |
| 1035 | * 4 = host unreachable |
| 1036 | * 5 = connection refused |
| 1037 | * 6 = TTL expired |
| 1038 | * 7 = command not supported |
| 1039 | * 8 = address type not supported |
| 1040 | * reserved (1 byte) = x00 |
| 1041 | * address type (1 byte) |
| 1042 | * 1 = IPv4 |
| 1043 | * 3 = domainname (first byte has length, no terminating null) |
| 1044 | * 4 = IPv6 |
| 1045 | * server bound address (variable) |
| 1046 | * server bound port (2 bytes) [network order] |
| 1047 | */ |
| 1048 | char data[5]; |
| 1049 | int len; |
| 1050 | |
| 1051 | /* First 5 bytes of packet are enough to tell its length. */ |
| 1052 | if (bufchain_size(&p->pending_input_data) < 5) |
| 1053 | return 1; /* not got anything yet */ |
| 1054 | |
| 1055 | /* get the response */ |
| 1056 | bufchain_fetch(&p->pending_input_data, data, 5); |
| 1057 | |
| 1058 | if (data[0] != 5) { |
| 1059 | plug_closing(p->plug, "Proxy error: SOCKS proxy returned wrong version number", |
| 1060 | PROXY_ERROR_GENERAL, 0); |
| 1061 | return 1; |
| 1062 | } |
| 1063 | |
| 1064 | if (data[1] != 0) { |
| 1065 | char buf[256]; |
| 1066 | |
| 1067 | strcpy(buf, "Proxy error: "); |
| 1068 | |
| 1069 | switch (data[1]) { |
| 1070 | case 1: strcat(buf, "General SOCKS server failure"); break; |
| 1071 | case 2: strcat(buf, "Connection not allowed by ruleset"); break; |
| 1072 | case 3: strcat(buf, "Network unreachable"); break; |
| 1073 | case 4: strcat(buf, "Host unreachable"); break; |
| 1074 | case 5: strcat(buf, "Connection refused"); break; |
| 1075 | case 6: strcat(buf, "TTL expired"); break; |
| 1076 | case 7: strcat(buf, "Command not supported"); break; |
| 1077 | case 8: strcat(buf, "Address type not supported"); break; |
| 1078 | default: sprintf(buf+strlen(buf), |
| 1079 | "Unrecognised SOCKS error code %d", |
| 1080 | data[1]); |
| 1081 | break; |
| 1082 | } |
| 1083 | plug_closing(p->plug, buf, PROXY_ERROR_GENERAL, 0); |
| 1084 | |
| 1085 | return 1; |
| 1086 | } |
| 1087 | |
| 1088 | /* |
| 1089 | * Eat the rest of the reply packet. |
| 1090 | */ |
| 1091 | len = 6; /* first 4 bytes, last 2 */ |
| 1092 | switch (data[3]) { |
| 1093 | case 1: len += 4; break; /* IPv4 address */ |
| 1094 | case 4: len += 16; break;/* IPv6 address */ |
| 1095 | case 3: len += (unsigned char)data[4]; break; /* domain name */ |
| 1096 | default: |
| 1097 | plug_closing(p->plug, "Proxy error: SOCKS proxy returned " |
| 1098 | "unrecognised address format", |
| 1099 | PROXY_ERROR_GENERAL, 0); |
| 1100 | return 1; |
| 1101 | } |
| 1102 | if (bufchain_size(&p->pending_input_data) < len) |
| 1103 | return 1; /* not got whole reply yet */ |
| 1104 | bufchain_consume(&p->pending_input_data, len); |
| 1105 | |
| 1106 | /* we're done */ |
| 1107 | proxy_activate(p); |
| 1108 | return 1; |
| 1109 | } |
| 1110 | |
| 1111 | if (p->state == 4) { |
| 1112 | /* TODO: Handle GSSAPI authentication */ |
| 1113 | plug_closing(p->plug, "Proxy error: We don't support GSSAPI authentication", |
| 1114 | PROXY_ERROR_GENERAL, 0); |
| 1115 | return 1; |
| 1116 | } |
| 1117 | |
| 1118 | if (p->state == 5) { |
| 1119 | if (p->cfg.proxy_username[0] || p->cfg.proxy_password[0]) { |
| 1120 | char userpwbuf[514]; |
| 1121 | int ulen, plen; |
| 1122 | ulen = strlen(p->cfg.proxy_username); |
| 1123 | if (ulen > 255) ulen = 255; if (ulen < 1) ulen = 1; |
| 1124 | plen = strlen(p->cfg.proxy_password); |
| 1125 | if (plen > 255) plen = 255; if (plen < 1) plen = 1; |
| 1126 | userpwbuf[0] = 1; /* version number of subnegotiation */ |
| 1127 | userpwbuf[1] = ulen; |
| 1128 | memcpy(userpwbuf+2, p->cfg.proxy_username, ulen); |
| 1129 | userpwbuf[ulen+2] = plen; |
| 1130 | memcpy(userpwbuf+ulen+3, p->cfg.proxy_password, plen); |
| 1131 | sk_write(p->sub_socket, userpwbuf, ulen + plen + 3); |
| 1132 | p->state = 7; |
| 1133 | } else |
| 1134 | plug_closing(p->plug, "Proxy error: Server chose " |
| 1135 | "username/password authentication but we " |
| 1136 | "didn't offer it!", |
| 1137 | PROXY_ERROR_GENERAL, 0); |
| 1138 | return 1; |
| 1139 | } |
| 1140 | |
| 1141 | if (p->state == 6) { |
| 1142 | /* TODO: Handle CHAP authentication */ |
| 1143 | plug_closing(p->plug, "Proxy error: We don't support CHAP authentication", |
| 1144 | PROXY_ERROR_GENERAL, 0); |
| 1145 | return 1; |
| 1146 | } |
| 1147 | |
| 1148 | } |
| 1149 | |
| 1150 | plug_closing(p->plug, "Proxy error: Unexpected proxy error", |
| 1151 | PROXY_ERROR_UNEXPECTED, 0); |
| 1152 | return 1; |
| 1153 | } |
| 1154 | |
| 1155 | /* ---------------------------------------------------------------------- |
| 1156 | * `Telnet' proxy type. |
| 1157 | * |
| 1158 | * (This is for ad-hoc proxies where you connect to the proxy's |
| 1159 | * telnet port and send a command such as `connect host port'. The |
| 1160 | * command is configurable, since this proxy type is typically not |
| 1161 | * standardised or at all well-defined.) |
| 1162 | */ |
| 1163 | |
| 1164 | int proxy_telnet_negotiate (Proxy_Socket p, int change) |
| 1165 | { |
| 1166 | if (p->state == PROXY_CHANGE_NEW) { |
| 1167 | |
| 1168 | int so = 0, eo = 0; |
| 1169 | |
| 1170 | /* we need to escape \\, \%, \r, \n, \t, \x??, \0???, |
| 1171 | * %%, %host, %port, %user, and %pass |
| 1172 | */ |
| 1173 | |
| 1174 | while (p->cfg.proxy_telnet_command[eo] != 0) { |
| 1175 | |
| 1176 | /* scan forward until we hit end-of-line, |
| 1177 | * or an escape character (\ or %) */ |
| 1178 | while (p->cfg.proxy_telnet_command[eo] != 0 && |
| 1179 | p->cfg.proxy_telnet_command[eo] != '%' && |
| 1180 | p->cfg.proxy_telnet_command[eo] != '\\') eo++; |
| 1181 | |
| 1182 | /* if we hit eol, break out of our escaping loop */ |
| 1183 | if (p->cfg.proxy_telnet_command[eo] == 0) break; |
| 1184 | |
| 1185 | /* if there was any unescaped text before the escape |
| 1186 | * character, send that now */ |
| 1187 | if (eo != so) { |
| 1188 | sk_write(p->sub_socket, |
| 1189 | p->cfg.proxy_telnet_command + so, eo - so); |
| 1190 | } |
| 1191 | |
| 1192 | so = eo++; |
| 1193 | |
| 1194 | /* if the escape character was the last character of |
| 1195 | * the line, we'll just stop and send it. */ |
| 1196 | if (p->cfg.proxy_telnet_command[eo] == 0) break; |
| 1197 | |
| 1198 | if (p->cfg.proxy_telnet_command[so] == '\\') { |
| 1199 | |
| 1200 | /* we recognize \\, \%, \r, \n, \t, \x??. |
| 1201 | * anything else, we just send unescaped (including the \). |
| 1202 | */ |
| 1203 | |
| 1204 | switch (p->cfg.proxy_telnet_command[eo]) { |
| 1205 | |
| 1206 | case '\\': |
| 1207 | sk_write(p->sub_socket, "\\", 1); |
| 1208 | eo++; |
| 1209 | break; |
| 1210 | |
| 1211 | case '%': |
| 1212 | sk_write(p->sub_socket, "%%", 1); |
| 1213 | eo++; |
| 1214 | break; |
| 1215 | |
| 1216 | case 'r': |
| 1217 | sk_write(p->sub_socket, "\r", 1); |
| 1218 | eo++; |
| 1219 | break; |
| 1220 | |
| 1221 | case 'n': |
| 1222 | sk_write(p->sub_socket, "\n", 1); |
| 1223 | eo++; |
| 1224 | break; |
| 1225 | |
| 1226 | case 't': |
| 1227 | sk_write(p->sub_socket, "\t", 1); |
| 1228 | eo++; |
| 1229 | break; |
| 1230 | |
| 1231 | case 'x': |
| 1232 | case 'X': |
| 1233 | { |
| 1234 | /* escaped hexadecimal value (ie. \xff) */ |
| 1235 | unsigned char v = 0; |
| 1236 | int i = 0; |
| 1237 | |
| 1238 | for (;;) { |
| 1239 | eo++; |
| 1240 | if (p->cfg.proxy_telnet_command[eo] >= '0' && |
| 1241 | p->cfg.proxy_telnet_command[eo] <= '9') |
| 1242 | v += p->cfg.proxy_telnet_command[eo] - '0'; |
| 1243 | else if (p->cfg.proxy_telnet_command[eo] >= 'a' && |
| 1244 | p->cfg.proxy_telnet_command[eo] <= 'f') |
| 1245 | v += p->cfg.proxy_telnet_command[eo] - 'a' + 10; |
| 1246 | else if (p->cfg.proxy_telnet_command[eo] >= 'A' && |
| 1247 | p->cfg.proxy_telnet_command[eo] <= 'F') |
| 1248 | v += p->cfg.proxy_telnet_command[eo] - 'A' + 10; |
| 1249 | else { |
| 1250 | /* non hex character, so we abort and just |
| 1251 | * send the whole thing unescaped (including \x) |
| 1252 | */ |
| 1253 | sk_write(p->sub_socket, "\\", 1); |
| 1254 | eo = so + 1; |
| 1255 | break; |
| 1256 | } |
| 1257 | |
| 1258 | /* we only extract two hex characters */ |
| 1259 | if (i == 1) { |
| 1260 | sk_write(p->sub_socket, (char *)&v, 1); |
| 1261 | eo++; |
| 1262 | break; |
| 1263 | } |
| 1264 | |
| 1265 | i++; |
| 1266 | v <<= 4; |
| 1267 | } |
| 1268 | } |
| 1269 | break; |
| 1270 | |
| 1271 | default: |
| 1272 | sk_write(p->sub_socket, |
| 1273 | p->cfg.proxy_telnet_command + so, 2); |
| 1274 | eo++; |
| 1275 | break; |
| 1276 | } |
| 1277 | } else { |
| 1278 | |
| 1279 | /* % escape. we recognize %%, %host, %port, %user, %pass. |
| 1280 | * anything else, we just send unescaped (including the %). |
| 1281 | */ |
| 1282 | |
| 1283 | if (p->cfg.proxy_telnet_command[eo] == '%') { |
| 1284 | sk_write(p->sub_socket, "%", 1); |
| 1285 | eo++; |
| 1286 | } |
| 1287 | else if (strnicmp(p->cfg.proxy_telnet_command + eo, |
| 1288 | "host", 4) == 0) { |
| 1289 | char dest[512]; |
| 1290 | sk_getaddr(p->remote_addr, dest, lenof(dest)); |
| 1291 | sk_write(p->sub_socket, dest, strlen(dest)); |
| 1292 | eo += 4; |
| 1293 | } |
| 1294 | else if (strnicmp(p->cfg.proxy_telnet_command + eo, |
| 1295 | "port", 4) == 0) { |
| 1296 | char port[8]; |
| 1297 | sprintf(port, "%i", p->remote_port); |
| 1298 | sk_write(p->sub_socket, port, strlen(port)); |
| 1299 | eo += 4; |
| 1300 | } |
| 1301 | else if (strnicmp(p->cfg.proxy_telnet_command + eo, |
| 1302 | "user", 4) == 0) { |
| 1303 | sk_write(p->sub_socket, p->cfg.proxy_username, |
| 1304 | strlen(p->cfg.proxy_username)); |
| 1305 | eo += 4; |
| 1306 | } |
| 1307 | else if (strnicmp(p->cfg.proxy_telnet_command + eo, |
| 1308 | "pass", 4) == 0) { |
| 1309 | sk_write(p->sub_socket, p->cfg.proxy_password, |
| 1310 | strlen(p->cfg.proxy_password)); |
| 1311 | eo += 4; |
| 1312 | } |
| 1313 | else { |
| 1314 | /* we don't escape this, so send the % now, and |
| 1315 | * don't advance eo, so that we'll consider the |
| 1316 | * text immediately following the % as unescaped. |
| 1317 | */ |
| 1318 | sk_write(p->sub_socket, "%", 1); |
| 1319 | } |
| 1320 | } |
| 1321 | |
| 1322 | /* resume scanning for additional escapes after this one. */ |
| 1323 | so = eo; |
| 1324 | } |
| 1325 | |
| 1326 | /* if there is any unescaped text at the end of the line, send it */ |
| 1327 | if (eo != so) { |
| 1328 | sk_write(p->sub_socket, p->cfg.proxy_telnet_command + so, eo - so); |
| 1329 | } |
| 1330 | |
| 1331 | p->state = 1; |
| 1332 | return 0; |
| 1333 | } |
| 1334 | |
| 1335 | if (change == PROXY_CHANGE_CLOSING) { |
| 1336 | /* if our proxy negotiation process involves closing and opening |
| 1337 | * new sockets, then we would want to intercept this closing |
| 1338 | * callback when we were expecting it. if we aren't anticipating |
| 1339 | * a socket close, then some error must have occurred. we'll |
| 1340 | * just pass those errors up to the backend. |
| 1341 | */ |
| 1342 | return plug_closing(p->plug, p->closing_error_msg, |
| 1343 | p->closing_error_code, |
| 1344 | p->closing_calling_back); |
| 1345 | } |
| 1346 | |
| 1347 | if (change == PROXY_CHANGE_SENT) { |
| 1348 | /* some (or all) of what we wrote to the proxy was sent. |
| 1349 | * we don't do anything new, however, until we receive the |
| 1350 | * proxy's response. we might want to set a timer so we can |
| 1351 | * timeout the proxy negotiation after a while... |
| 1352 | */ |
| 1353 | return 0; |
| 1354 | } |
| 1355 | |
| 1356 | if (change == PROXY_CHANGE_ACCEPTING) { |
| 1357 | /* we should _never_ see this, as we are using our socket to |
| 1358 | * connect to a proxy, not accepting inbound connections. |
| 1359 | * what should we do? close the socket with an appropriate |
| 1360 | * error message? |
| 1361 | */ |
| 1362 | return plug_accepting(p->plug, p->accepting_sock); |
| 1363 | } |
| 1364 | |
| 1365 | if (change == PROXY_CHANGE_RECEIVE) { |
| 1366 | /* we have received data from the underlying socket, which |
| 1367 | * we'll need to parse, process, and respond to appropriately. |
| 1368 | */ |
| 1369 | |
| 1370 | /* we're done */ |
| 1371 | proxy_activate(p); |
| 1372 | /* proxy activate will have dealt with |
| 1373 | * whatever is left of the buffer */ |
| 1374 | return 1; |
| 1375 | } |
| 1376 | |
| 1377 | plug_closing(p->plug, "Proxy error: Unexpected proxy error", |
| 1378 | PROXY_ERROR_UNEXPECTED, 0); |
| 1379 | return 1; |
| 1380 | } |