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Commit | Line | Data |
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1c1af145 | 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_SOCKS4)) | |
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 | sk_addr_free(ps->remote_addr); | |
92 | sfree(ps); | |
93 | } | |
94 | ||
95 | static int sk_proxy_write (Socket s, const char *data, int len) | |
96 | { | |
97 | Proxy_Socket ps = (Proxy_Socket) s; | |
98 | ||
99 | if (ps->state != PROXY_STATE_ACTIVE) { | |
100 | bufchain_add(&ps->pending_output_data, data, len); | |
101 | return bufchain_size(&ps->pending_output_data); | |
102 | } | |
103 | return sk_write(ps->sub_socket, data, len); | |
104 | } | |
105 | ||
106 | static int sk_proxy_write_oob (Socket s, const char *data, int len) | |
107 | { | |
108 | Proxy_Socket ps = (Proxy_Socket) s; | |
109 | ||
110 | if (ps->state != PROXY_STATE_ACTIVE) { | |
111 | bufchain_clear(&ps->pending_output_data); | |
112 | bufchain_clear(&ps->pending_oob_output_data); | |
113 | bufchain_add(&ps->pending_oob_output_data, data, len); | |
114 | return len; | |
115 | } | |
116 | return sk_write_oob(ps->sub_socket, data, len); | |
117 | } | |
118 | ||
119 | static void sk_proxy_flush (Socket s) | |
120 | { | |
121 | Proxy_Socket ps = (Proxy_Socket) s; | |
122 | ||
123 | if (ps->state != PROXY_STATE_ACTIVE) { | |
124 | ps->pending_flush = 1; | |
125 | return; | |
126 | } | |
127 | sk_flush(ps->sub_socket); | |
128 | } | |
129 | ||
130 | static void sk_proxy_set_private_ptr (Socket s, void *ptr) | |
131 | { | |
132 | Proxy_Socket ps = (Proxy_Socket) s; | |
133 | sk_set_private_ptr(ps->sub_socket, ptr); | |
134 | } | |
135 | ||
136 | static void * sk_proxy_get_private_ptr (Socket s) | |
137 | { | |
138 | Proxy_Socket ps = (Proxy_Socket) s; | |
139 | return sk_get_private_ptr(ps->sub_socket); | |
140 | } | |
141 | ||
142 | static void sk_proxy_set_frozen (Socket s, int is_frozen) | |
143 | { | |
144 | Proxy_Socket ps = (Proxy_Socket) s; | |
145 | ||
146 | if (ps->state != PROXY_STATE_ACTIVE) { | |
147 | ps->freeze = is_frozen; | |
148 | return; | |
149 | } | |
150 | ||
151 | /* handle any remaining buffered recv data first */ | |
152 | if (bufchain_size(&ps->pending_input_data) > 0) { | |
153 | ps->freeze = is_frozen; | |
154 | ||
155 | /* loop while we still have buffered data, and while we are | |
156 | * unfrozen. the plug_receive call in the loop could result | |
157 | * in a call back into this function refreezing the socket, | |
158 | * so we have to check each time. | |
159 | */ | |
160 | while (!ps->freeze && bufchain_size(&ps->pending_input_data) > 0) { | |
161 | void *data; | |
162 | char databuf[512]; | |
163 | int len; | |
164 | bufchain_prefix(&ps->pending_input_data, &data, &len); | |
165 | if (len > lenof(databuf)) | |
166 | len = lenof(databuf); | |
167 | memcpy(databuf, data, len); | |
168 | bufchain_consume(&ps->pending_input_data, len); | |
169 | plug_receive(ps->plug, 0, databuf, len); | |
170 | } | |
171 | ||
172 | /* if we're still frozen, we'll have to wait for another | |
173 | * call from the backend to finish unbuffering the data. | |
174 | */ | |
175 | if (ps->freeze) return; | |
176 | } | |
177 | ||
178 | sk_set_frozen(ps->sub_socket, is_frozen); | |
179 | } | |
180 | ||
181 | static const char * sk_proxy_socket_error (Socket s) | |
182 | { | |
183 | Proxy_Socket ps = (Proxy_Socket) s; | |
184 | if (ps->error != NULL || ps->sub_socket == NULL) { | |
185 | return ps->error; | |
186 | } | |
187 | return sk_socket_error(ps->sub_socket); | |
188 | } | |
189 | ||
190 | /* basic proxy plug functions */ | |
191 | ||
192 | static void plug_proxy_log(Plug plug, int type, SockAddr addr, int port, | |
193 | const char *error_msg, int error_code) | |
194 | { | |
195 | Proxy_Plug pp = (Proxy_Plug) plug; | |
196 | Proxy_Socket ps = pp->proxy_socket; | |
197 | ||
198 | plug_log(ps->plug, type, addr, port, error_msg, error_code); | |
199 | } | |
200 | ||
201 | static int plug_proxy_closing (Plug p, const char *error_msg, | |
202 | int error_code, int calling_back) | |
203 | { | |
204 | Proxy_Plug pp = (Proxy_Plug) p; | |
205 | Proxy_Socket ps = pp->proxy_socket; | |
206 | ||
207 | if (ps->state != PROXY_STATE_ACTIVE) { | |
208 | ps->closing_error_msg = error_msg; | |
209 | ps->closing_error_code = error_code; | |
210 | ps->closing_calling_back = calling_back; | |
211 | return ps->negotiate(ps, PROXY_CHANGE_CLOSING); | |
212 | } | |
213 | return plug_closing(ps->plug, error_msg, | |
214 | error_code, calling_back); | |
215 | } | |
216 | ||
217 | static int plug_proxy_receive (Plug p, int urgent, char *data, int len) | |
218 | { | |
219 | Proxy_Plug pp = (Proxy_Plug) p; | |
220 | Proxy_Socket ps = pp->proxy_socket; | |
221 | ||
222 | if (ps->state != PROXY_STATE_ACTIVE) { | |
223 | /* we will lose the urgentness of this data, but since most, | |
224 | * if not all, of this data will be consumed by the negotiation | |
225 | * process, hopefully it won't affect the protocol above us | |
226 | */ | |
227 | bufchain_add(&ps->pending_input_data, data, len); | |
228 | ps->receive_urgent = urgent; | |
229 | ps->receive_data = data; | |
230 | ps->receive_len = len; | |
231 | return ps->negotiate(ps, PROXY_CHANGE_RECEIVE); | |
232 | } | |
233 | return plug_receive(ps->plug, urgent, data, len); | |
234 | } | |
235 | ||
236 | static void plug_proxy_sent (Plug p, int bufsize) | |
237 | { | |
238 | Proxy_Plug pp = (Proxy_Plug) p; | |
239 | Proxy_Socket ps = pp->proxy_socket; | |
240 | ||
241 | if (ps->state != PROXY_STATE_ACTIVE) { | |
242 | ps->sent_bufsize = bufsize; | |
243 | ps->negotiate(ps, PROXY_CHANGE_SENT); | |
244 | return; | |
245 | } | |
246 | plug_sent(ps->plug, bufsize); | |
247 | } | |
248 | ||
249 | static int plug_proxy_accepting (Plug p, OSSocket sock) | |
250 | { | |
251 | Proxy_Plug pp = (Proxy_Plug) p; | |
252 | Proxy_Socket ps = pp->proxy_socket; | |
253 | ||
254 | if (ps->state != PROXY_STATE_ACTIVE) { | |
255 | ps->accepting_sock = sock; | |
256 | return ps->negotiate(ps, PROXY_CHANGE_ACCEPTING); | |
257 | } | |
258 | return plug_accepting(ps->plug, sock); | |
259 | } | |
260 | ||
261 | /* | |
262 | * This function can accept a NULL pointer as `addr', in which case | |
263 | * it will only check the host name. | |
264 | */ | |
265 | static int proxy_for_destination (SockAddr addr, char *hostname, int port, | |
266 | const Config *cfg) | |
267 | { | |
268 | int s = 0, e = 0; | |
269 | char hostip[64]; | |
270 | int hostip_len, hostname_len; | |
271 | const char *exclude_list; | |
272 | ||
273 | /* | |
274 | * Check the host name and IP against the hard-coded | |
275 | * representations of `localhost'. | |
276 | */ | |
277 | if (!cfg->even_proxy_localhost && | |
278 | (sk_hostname_is_local(hostname) || | |
279 | (addr && sk_address_is_local(addr)))) | |
280 | return 0; /* do not proxy */ | |
281 | ||
282 | /* we want a string representation of the IP address for comparisons */ | |
283 | if (addr) { | |
284 | sk_getaddr(addr, hostip, 64); | |
285 | hostip_len = strlen(hostip); | |
286 | } else | |
287 | hostip_len = 0; /* placate gcc; shouldn't be required */ | |
288 | ||
289 | hostname_len = strlen(hostname); | |
290 | ||
291 | exclude_list = cfg->proxy_exclude_list; | |
292 | ||
293 | /* now parse the exclude list, and see if either our IP | |
294 | * or hostname matches anything in it. | |
295 | */ | |
296 | ||
297 | while (exclude_list[s]) { | |
298 | while (exclude_list[s] && | |
299 | (isspace((unsigned char)exclude_list[s]) || | |
300 | exclude_list[s] == ',')) s++; | |
301 | ||
302 | if (!exclude_list[s]) break; | |
303 | ||
304 | e = s; | |
305 | ||
306 | while (exclude_list[e] && | |
307 | (isalnum((unsigned char)exclude_list[e]) || | |
308 | exclude_list[e] == '-' || | |
309 | exclude_list[e] == '.' || | |
310 | exclude_list[e] == '*')) e++; | |
311 | ||
312 | if (exclude_list[s] == '*') { | |
313 | /* wildcard at beginning of entry */ | |
314 | ||
315 | if ((addr && strnicmp(hostip + hostip_len - (e - s - 1), | |
316 | exclude_list + s + 1, e - s - 1) == 0) || | |
317 | strnicmp(hostname + hostname_len - (e - s - 1), | |
318 | exclude_list + s + 1, e - s - 1) == 0) | |
319 | return 0; /* IP/hostname range excluded. do not use proxy. */ | |
320 | ||
321 | } else if (exclude_list[e-1] == '*') { | |
322 | /* wildcard at end of entry */ | |
323 | ||
324 | if ((addr && strnicmp(hostip, exclude_list + s, e - s - 1) == 0) || | |
325 | strnicmp(hostname, exclude_list + s, e - s - 1) == 0) | |
326 | return 0; /* IP/hostname range excluded. do not use proxy. */ | |
327 | ||
328 | } else { | |
329 | /* no wildcard at either end, so let's try an absolute | |
330 | * match (ie. a specific IP) | |
331 | */ | |
332 | ||
333 | if (addr && strnicmp(hostip, exclude_list + s, e - s) == 0) | |
334 | return 0; /* IP/hostname excluded. do not use proxy. */ | |
335 | if (strnicmp(hostname, exclude_list + s, e - s) == 0) | |
336 | return 0; /* IP/hostname excluded. do not use proxy. */ | |
337 | } | |
338 | ||
339 | s = e; | |
340 | ||
341 | /* Make sure we really have reached the next comma or end-of-string */ | |
342 | while (exclude_list[s] && | |
343 | !isspace((unsigned char)exclude_list[s]) && | |
344 | exclude_list[s] != ',') s++; | |
345 | } | |
346 | ||
347 | /* no matches in the exclude list, so use the proxy */ | |
348 | return 1; | |
349 | } | |
350 | ||
351 | SockAddr name_lookup(char *host, int port, char **canonicalname, | |
352 | const Config *cfg, int addressfamily) | |
353 | { | |
354 | if (cfg->proxy_type != PROXY_NONE && | |
355 | do_proxy_dns(cfg) && | |
356 | proxy_for_destination(NULL, host, port, cfg)) { | |
357 | *canonicalname = dupstr(host); | |
358 | return sk_nonamelookup(host); | |
359 | } | |
360 | ||
361 | return sk_namelookup(host, canonicalname, addressfamily); | |
362 | } | |
363 | ||
364 | Socket new_connection(SockAddr addr, char *hostname, | |
365 | int port, int privport, | |
366 | int oobinline, int nodelay, int keepalive, | |
367 | Plug plug, const Config *cfg) | |
368 | { | |
369 | static const struct socket_function_table socket_fn_table = { | |
370 | sk_proxy_plug, | |
371 | sk_proxy_close, | |
372 | sk_proxy_write, | |
373 | sk_proxy_write_oob, | |
374 | sk_proxy_flush, | |
375 | sk_proxy_set_private_ptr, | |
376 | sk_proxy_get_private_ptr, | |
377 | sk_proxy_set_frozen, | |
378 | sk_proxy_socket_error | |
379 | }; | |
380 | ||
381 | static const struct plug_function_table plug_fn_table = { | |
382 | plug_proxy_log, | |
383 | plug_proxy_closing, | |
384 | plug_proxy_receive, | |
385 | plug_proxy_sent, | |
386 | plug_proxy_accepting | |
387 | }; | |
388 | ||
389 | if (cfg->proxy_type != PROXY_NONE && | |
390 | proxy_for_destination(addr, hostname, port, cfg)) | |
391 | { | |
392 | Proxy_Socket ret; | |
393 | Proxy_Plug pplug; | |
394 | SockAddr proxy_addr; | |
395 | char *proxy_canonical_name; | |
396 | Socket sret; | |
397 | ||
398 | if ((sret = platform_new_connection(addr, hostname, port, privport, | |
399 | oobinline, nodelay, keepalive, | |
400 | plug, cfg)) != | |
401 | NULL) | |
402 | return sret; | |
403 | ||
404 | ret = snew(struct Socket_proxy_tag); | |
405 | ret->fn = &socket_fn_table; | |
406 | ret->cfg = *cfg; /* STRUCTURE COPY */ | |
407 | ret->plug = plug; | |
408 | ret->remote_addr = addr; /* will need to be freed on close */ | |
409 | ret->remote_port = port; | |
410 | ||
411 | ret->error = NULL; | |
412 | ret->pending_flush = 0; | |
413 | ret->freeze = 0; | |
414 | ||
415 | bufchain_init(&ret->pending_input_data); | |
416 | bufchain_init(&ret->pending_output_data); | |
417 | bufchain_init(&ret->pending_oob_output_data); | |
418 | ||
419 | ret->sub_socket = NULL; | |
420 | ret->state = PROXY_STATE_NEW; | |
421 | ret->negotiate = NULL; | |
422 | ||
423 | if (cfg->proxy_type == PROXY_HTTP) { | |
424 | ret->negotiate = proxy_http_negotiate; | |
425 | } else if (cfg->proxy_type == PROXY_SOCKS4) { | |
426 | ret->negotiate = proxy_socks4_negotiate; | |
427 | } else if (cfg->proxy_type == PROXY_SOCKS5) { | |
428 | ret->negotiate = proxy_socks5_negotiate; | |
429 | } else if (cfg->proxy_type == PROXY_TELNET) { | |
430 | ret->negotiate = proxy_telnet_negotiate; | |
431 | } else { | |
432 | ret->error = "Proxy error: Unknown proxy method"; | |
433 | return (Socket) ret; | |
434 | } | |
435 | ||
436 | /* create the proxy plug to map calls from the actual | |
437 | * socket into our proxy socket layer */ | |
438 | pplug = snew(struct Plug_proxy_tag); | |
439 | pplug->fn = &plug_fn_table; | |
440 | pplug->proxy_socket = ret; | |
441 | ||
442 | /* look-up proxy */ | |
443 | proxy_addr = sk_namelookup(cfg->proxy_host, | |
444 | &proxy_canonical_name, cfg->addressfamily); | |
445 | if (sk_addr_error(proxy_addr) != NULL) { | |
446 | ret->error = "Proxy error: Unable to resolve proxy host name"; | |
447 | return (Socket)ret; | |
448 | } | |
449 | sfree(proxy_canonical_name); | |
450 | ||
451 | /* create the actual socket we will be using, | |
452 | * connected to our proxy server and port. | |
453 | */ | |
454 | ret->sub_socket = sk_new(proxy_addr, cfg->proxy_port, | |
455 | privport, oobinline, | |
456 | nodelay, keepalive, (Plug) pplug); | |
457 | if (sk_socket_error(ret->sub_socket) != NULL) | |
458 | return (Socket) ret; | |
459 | ||
460 | /* start the proxy negotiation process... */ | |
461 | sk_set_frozen(ret->sub_socket, 0); | |
462 | ret->negotiate(ret, PROXY_CHANGE_NEW); | |
463 | ||
464 | return (Socket) ret; | |
465 | } | |
466 | ||
467 | /* no proxy, so just return the direct socket */ | |
468 | return sk_new(addr, port, privport, oobinline, nodelay, keepalive, plug); | |
469 | } | |
470 | ||
471 | Socket new_listener(char *srcaddr, int port, Plug plug, int local_host_only, | |
472 | const Config *cfg, int addressfamily) | |
473 | { | |
474 | /* TODO: SOCKS (and potentially others) support inbound | |
475 | * TODO: connections via the proxy. support them. | |
476 | */ | |
477 | ||
478 | return sk_newlistener(srcaddr, port, plug, local_host_only, addressfamily); | |
479 | } | |
480 | ||
481 | /* ---------------------------------------------------------------------- | |
482 | * HTTP CONNECT proxy type. | |
483 | */ | |
484 | ||
485 | static int get_line_end (char * data, int len) | |
486 | { | |
487 | int off = 0; | |
488 | ||
489 | while (off < len) | |
490 | { | |
491 | if (data[off] == '\n') { | |
492 | /* we have a newline */ | |
493 | off++; | |
494 | ||
495 | /* is that the only thing on this line? */ | |
496 | if (off <= 2) return off; | |
497 | ||
498 | /* if not, then there is the possibility that this header | |
499 | * continues onto the next line, if it starts with a space | |
500 | * or a tab. | |
501 | */ | |
502 | ||
503 | if (off + 1 < len && | |
504 | data[off+1] != ' ' && | |
505 | data[off+1] != '\t') return off; | |
506 | ||
507 | /* the line does continue, so we have to keep going | |
508 | * until we see an the header's "real" end of line. | |
509 | */ | |
510 | off++; | |
511 | } | |
512 | ||
513 | off++; | |
514 | } | |
515 | ||
516 | return -1; | |
517 | } | |
518 | ||
519 | int proxy_http_negotiate (Proxy_Socket p, int change) | |
520 | { | |
521 | if (p->state == PROXY_STATE_NEW) { | |
522 | /* we are just beginning the proxy negotiate process, | |
523 | * so we'll send off the initial bits of the request. | |
524 | * for this proxy method, it's just a simple HTTP | |
525 | * request | |
526 | */ | |
527 | char *buf, dest[512]; | |
528 | ||
529 | sk_getaddr(p->remote_addr, dest, lenof(dest)); | |
530 | ||
531 | buf = dupprintf("CONNECT %s:%i HTTP/1.1\r\nHost: %s:%i\r\n", | |
532 | dest, p->remote_port, dest, p->remote_port); | |
533 | sk_write(p->sub_socket, buf, strlen(buf)); | |
534 | sfree(buf); | |
535 | ||
536 | if (p->cfg.proxy_username[0] || p->cfg.proxy_password[0]) { | |
537 | char buf[sizeof(p->cfg.proxy_username)+sizeof(p->cfg.proxy_password)]; | |
538 | char buf2[sizeof(buf)*4/3 + 100]; | |
539 | int i, j, len; | |
540 | sprintf(buf, "%s:%s", p->cfg.proxy_username, p->cfg.proxy_password); | |
541 | len = strlen(buf); | |
542 | sprintf(buf2, "Proxy-Authorization: Basic "); | |
543 | for (i = 0, j = strlen(buf2); i < len; i += 3, j += 4) | |
544 | base64_encode_atom((unsigned char *)(buf+i), | |
545 | (len-i > 3 ? 3 : len-i), buf2+j); | |
546 | strcpy(buf2+j, "\r\n"); | |
547 | sk_write(p->sub_socket, buf2, strlen(buf2)); | |
548 | } | |
549 | ||
550 | sk_write(p->sub_socket, "\r\n", 2); | |
551 | ||
552 | p->state = 1; | |
553 | return 0; | |
554 | } | |
555 | ||
556 | if (change == PROXY_CHANGE_CLOSING) { | |
557 | /* if our proxy negotiation process involves closing and opening | |
558 | * new sockets, then we would want to intercept this closing | |
559 | * callback when we were expecting it. if we aren't anticipating | |
560 | * a socket close, then some error must have occurred. we'll | |
561 | * just pass those errors up to the backend. | |
562 | */ | |
563 | return plug_closing(p->plug, p->closing_error_msg, | |
564 | p->closing_error_code, | |
565 | p->closing_calling_back); | |
566 | } | |
567 | ||
568 | if (change == PROXY_CHANGE_SENT) { | |
569 | /* some (or all) of what we wrote to the proxy was sent. | |
570 | * we don't do anything new, however, until we receive the | |
571 | * proxy's response. we might want to set a timer so we can | |
572 | * timeout the proxy negotiation after a while... | |
573 | */ | |
574 | return 0; | |
575 | } | |
576 | ||
577 | if (change == PROXY_CHANGE_ACCEPTING) { | |
578 | /* we should _never_ see this, as we are using our socket to | |
579 | * connect to a proxy, not accepting inbound connections. | |
580 | * what should we do? close the socket with an appropriate | |
581 | * error message? | |
582 | */ | |
583 | return plug_accepting(p->plug, p->accepting_sock); | |
584 | } | |
585 | ||
586 | if (change == PROXY_CHANGE_RECEIVE) { | |
587 | /* we have received data from the underlying socket, which | |
588 | * we'll need to parse, process, and respond to appropriately. | |
589 | */ | |
590 | ||
591 | char *data, *datap; | |
592 | int len; | |
593 | int eol; | |
594 | ||
595 | if (p->state == 1) { | |
596 | ||
597 | int min_ver, maj_ver, status; | |
598 | ||
599 | /* get the status line */ | |
600 | len = bufchain_size(&p->pending_input_data); | |
601 | assert(len > 0); /* or we wouldn't be here */ | |
602 | data = snewn(len+1, char); | |
603 | bufchain_fetch(&p->pending_input_data, data, len); | |
604 | /* | |
605 | * We must NUL-terminate this data, because Windows | |
606 | * sscanf appears to require a NUL at the end of the | |
607 | * string because it strlens it _first_. Sigh. | |
608 | */ | |
609 | data[len] = '\0'; | |
610 | ||
611 | eol = get_line_end(data, len); | |
612 | if (eol < 0) { | |
613 | sfree(data); | |
614 | return 1; | |
615 | } | |
616 | ||
617 | status = -1; | |
618 | /* We can't rely on whether the %n incremented the sscanf return */ | |
619 | if (sscanf((char *)data, "HTTP/%i.%i %n", | |
620 | &maj_ver, &min_ver, &status) < 2 || status == -1) { | |
621 | plug_closing(p->plug, "Proxy error: HTTP response was absent", | |
622 | PROXY_ERROR_GENERAL, 0); | |
623 | sfree(data); | |
624 | return 1; | |
625 | } | |
626 | ||
627 | /* remove the status line from the input buffer. */ | |
628 | bufchain_consume(&p->pending_input_data, eol); | |
629 | if (data[status] != '2') { | |
630 | /* error */ | |
631 | char *buf; | |
632 | data[eol] = '\0'; | |
633 | while (eol > status && | |
634 | (data[eol-1] == '\r' || data[eol-1] == '\n')) | |
635 | data[--eol] = '\0'; | |
636 | buf = dupprintf("Proxy error: %s", data+status); | |
637 | plug_closing(p->plug, buf, PROXY_ERROR_GENERAL, 0); | |
638 | sfree(buf); | |
639 | sfree(data); | |
640 | return 1; | |
641 | } | |
642 | ||
643 | sfree(data); | |
644 | ||
645 | p->state = 2; | |
646 | } | |
647 | ||
648 | if (p->state == 2) { | |
649 | ||
650 | /* get headers. we're done when we get a | |
651 | * header of length 2, (ie. just "\r\n") | |
652 | */ | |
653 | ||
654 | len = bufchain_size(&p->pending_input_data); | |
655 | assert(len > 0); /* or we wouldn't be here */ | |
656 | data = snewn(len, char); | |
657 | datap = data; | |
658 | bufchain_fetch(&p->pending_input_data, data, len); | |
659 | ||
660 | eol = get_line_end(datap, len); | |
661 | if (eol < 0) { | |
662 | sfree(data); | |
663 | return 1; | |
664 | } | |
665 | while (eol > 2) | |
666 | { | |
667 | bufchain_consume(&p->pending_input_data, eol); | |
668 | datap += eol; | |
669 | len -= eol; | |
670 | eol = get_line_end(datap, len); | |
671 | } | |
672 | ||
673 | if (eol == 2) { | |
674 | /* we're done */ | |
675 | bufchain_consume(&p->pending_input_data, 2); | |
676 | proxy_activate(p); | |
677 | /* proxy activate will have dealt with | |
678 | * whatever is left of the buffer */ | |
679 | sfree(data); | |
680 | return 1; | |
681 | } | |
682 | ||
683 | sfree(data); | |
684 | return 1; | |
685 | } | |
686 | } | |
687 | ||
688 | plug_closing(p->plug, "Proxy error: unexpected proxy error", | |
689 | PROXY_ERROR_UNEXPECTED, 0); | |
690 | return 1; | |
691 | } | |
692 | ||
693 | /* ---------------------------------------------------------------------- | |
694 | * SOCKS proxy type. | |
695 | */ | |
696 | ||
697 | /* SOCKS version 4 */ | |
698 | int proxy_socks4_negotiate (Proxy_Socket p, int change) | |
699 | { | |
700 | if (p->state == PROXY_CHANGE_NEW) { | |
701 | ||
702 | /* request format: | |
703 | * version number (1 byte) = 4 | |
704 | * command code (1 byte) | |
705 | * 1 = CONNECT | |
706 | * 2 = BIND | |
707 | * dest. port (2 bytes) [network order] | |
708 | * dest. address (4 bytes) | |
709 | * user ID (variable length, null terminated string) | |
710 | */ | |
711 | ||
712 | int length, type, namelen; | |
713 | char *command, addr[4], hostname[512]; | |
714 | ||
715 | type = sk_addrtype(p->remote_addr); | |
716 | if (type == ADDRTYPE_IPV6) { | |
717 | plug_closing(p->plug, "Proxy error: SOCKS version 4 does" | |
718 | " not support IPv6", PROXY_ERROR_GENERAL, 0); | |
719 | return 1; | |
720 | } else if (type == ADDRTYPE_IPV4) { | |
721 | namelen = 0; | |
722 | sk_addrcopy(p->remote_addr, addr); | |
723 | } else { /* type == ADDRTYPE_NAME */ | |
724 | assert(type == ADDRTYPE_NAME); | |
725 | sk_getaddr(p->remote_addr, hostname, lenof(hostname)); | |
726 | namelen = strlen(hostname) + 1; /* include the NUL */ | |
727 | addr[0] = addr[1] = addr[2] = 0; | |
728 | addr[3] = 1; | |
729 | } | |
730 | ||
731 | length = strlen(p->cfg.proxy_username) + namelen + 9; | |
732 | command = snewn(length, char); | |
733 | strcpy(command + 8, p->cfg.proxy_username); | |
734 | ||
735 | command[0] = 4; /* version 4 */ | |
736 | command[1] = 1; /* CONNECT command */ | |
737 | ||
738 | /* port */ | |
739 | command[2] = (char) (p->remote_port >> 8) & 0xff; | |
740 | command[3] = (char) p->remote_port & 0xff; | |
741 | ||
742 | /* address */ | |
743 | memcpy(command + 4, addr, 4); | |
744 | ||
745 | /* hostname */ | |
746 | memcpy(command + 8 + strlen(p->cfg.proxy_username) + 1, | |
747 | hostname, namelen); | |
748 | ||
749 | sk_write(p->sub_socket, command, length); | |
750 | sfree(command); | |
751 | ||
752 | p->state = 1; | |
753 | return 0; | |
754 | } | |
755 | ||
756 | if (change == PROXY_CHANGE_CLOSING) { | |
757 | /* if our proxy negotiation process involves closing and opening | |
758 | * new sockets, then we would want to intercept this closing | |
759 | * callback when we were expecting it. if we aren't anticipating | |
760 | * a socket close, then some error must have occurred. we'll | |
761 | * just pass those errors up to the backend. | |
762 | */ | |
763 | return plug_closing(p->plug, p->closing_error_msg, | |
764 | p->closing_error_code, | |
765 | p->closing_calling_back); | |
766 | } | |
767 | ||
768 | if (change == PROXY_CHANGE_SENT) { | |
769 | /* some (or all) of what we wrote to the proxy was sent. | |
770 | * we don't do anything new, however, until we receive the | |
771 | * proxy's response. we might want to set a timer so we can | |
772 | * timeout the proxy negotiation after a while... | |
773 | */ | |
774 | return 0; | |
775 | } | |
776 | ||
777 | if (change == PROXY_CHANGE_ACCEPTING) { | |
778 | /* we should _never_ see this, as we are using our socket to | |
779 | * connect to a proxy, not accepting inbound connections. | |
780 | * what should we do? close the socket with an appropriate | |
781 | * error message? | |
782 | */ | |
783 | return plug_accepting(p->plug, p->accepting_sock); | |
784 | } | |
785 | ||
786 | if (change == PROXY_CHANGE_RECEIVE) { | |
787 | /* we have received data from the underlying socket, which | |
788 | * we'll need to parse, process, and respond to appropriately. | |
789 | */ | |
790 | ||
791 | if (p->state == 1) { | |
792 | /* response format: | |
793 | * version number (1 byte) = 4 | |
794 | * reply code (1 byte) | |
795 | * 90 = request granted | |
796 | * 91 = request rejected or failed | |
797 | * 92 = request rejected due to lack of IDENTD on client | |
798 | * 93 = request rejected due to difference in user ID | |
799 | * (what we sent vs. what IDENTD said) | |
800 | * dest. port (2 bytes) | |
801 | * dest. address (4 bytes) | |
802 | */ | |
803 | ||
804 | char data[8]; | |
805 | ||
806 | if (bufchain_size(&p->pending_input_data) < 8) | |
807 | return 1; /* not got anything yet */ | |
808 | ||
809 | /* get the response */ | |
810 | bufchain_fetch(&p->pending_input_data, data, 8); | |
811 | ||
812 | if (data[0] != 0) { | |
813 | plug_closing(p->plug, "Proxy error: SOCKS proxy responded with " | |
814 | "unexpected reply code version", | |
815 | PROXY_ERROR_GENERAL, 0); | |
816 | return 1; | |
817 | } | |
818 | ||
819 | if (data[1] != 90) { | |
820 | ||
821 | switch (data[1]) { | |
822 | case 92: | |
823 | plug_closing(p->plug, "Proxy error: SOCKS server wanted IDENTD on client", | |
824 | PROXY_ERROR_GENERAL, 0); | |
825 | break; | |
826 | case 93: | |
827 | plug_closing(p->plug, "Proxy error: Username and IDENTD on client don't agree", | |
828 | PROXY_ERROR_GENERAL, 0); | |
829 | break; | |
830 | case 91: | |
831 | default: | |
832 | plug_closing(p->plug, "Proxy error: Error while communicating with proxy", | |
833 | PROXY_ERROR_GENERAL, 0); | |
834 | break; | |
835 | } | |
836 | ||
837 | return 1; | |
838 | } | |
839 | bufchain_consume(&p->pending_input_data, 8); | |
840 | ||
841 | /* we're done */ | |
842 | proxy_activate(p); | |
843 | /* proxy activate will have dealt with | |
844 | * whatever is left of the buffer */ | |
845 | return 1; | |
846 | } | |
847 | } | |
848 | ||
849 | plug_closing(p->plug, "Proxy error: unexpected proxy error", | |
850 | PROXY_ERROR_UNEXPECTED, 0); | |
851 | return 1; | |
852 | } | |
853 | ||
854 | /* SOCKS version 5 */ | |
855 | int proxy_socks5_negotiate (Proxy_Socket p, int change) | |
856 | { | |
857 | if (p->state == PROXY_CHANGE_NEW) { | |
858 | ||
859 | /* initial command: | |
860 | * version number (1 byte) = 5 | |
861 | * number of available authentication methods (1 byte) | |
862 | * available authentication methods (1 byte * previous value) | |
863 | * authentication methods: | |
864 | * 0x00 = no authentication | |
865 | * 0x01 = GSSAPI | |
866 | * 0x02 = username/password | |
867 | * 0x03 = CHAP | |
868 | */ | |
869 | ||
870 | char command[5]; | |
871 | int len; | |
872 | ||
873 | command[0] = 5; /* version 5 */ | |
874 | if (p->cfg.proxy_username[0] || p->cfg.proxy_password[0]) { | |
875 | command[2] = 0x00; /* no authentication */ | |
876 | len = 3; | |
877 | proxy_socks5_offerencryptedauth (command, &len); | |
878 | command[len++] = 0x02; /* username/password */ | |
879 | command[1] = len - 2; /* Number of methods supported */ | |
880 | } else { | |
881 | command[1] = 1; /* one methods supported: */ | |
882 | command[2] = 0x00; /* no authentication */ | |
883 | len = 3; | |
884 | } | |
885 | ||
886 | sk_write(p->sub_socket, command, len); | |
887 | ||
888 | p->state = 1; | |
889 | return 0; | |
890 | } | |
891 | ||
892 | if (change == PROXY_CHANGE_CLOSING) { | |
893 | /* if our proxy negotiation process involves closing and opening | |
894 | * new sockets, then we would want to intercept this closing | |
895 | * callback when we were expecting it. if we aren't anticipating | |
896 | * a socket close, then some error must have occurred. we'll | |
897 | * just pass those errors up to the backend. | |
898 | */ | |
899 | return plug_closing(p->plug, p->closing_error_msg, | |
900 | p->closing_error_code, | |
901 | p->closing_calling_back); | |
902 | } | |
903 | ||
904 | if (change == PROXY_CHANGE_SENT) { | |
905 | /* some (or all) of what we wrote to the proxy was sent. | |
906 | * we don't do anything new, however, until we receive the | |
907 | * proxy's response. we might want to set a timer so we can | |
908 | * timeout the proxy negotiation after a while... | |
909 | */ | |
910 | return 0; | |
911 | } | |
912 | ||
913 | if (change == PROXY_CHANGE_ACCEPTING) { | |
914 | /* we should _never_ see this, as we are using our socket to | |
915 | * connect to a proxy, not accepting inbound connections. | |
916 | * what should we do? close the socket with an appropriate | |
917 | * error message? | |
918 | */ | |
919 | return plug_accepting(p->plug, p->accepting_sock); | |
920 | } | |
921 | ||
922 | if (change == PROXY_CHANGE_RECEIVE) { | |
923 | /* we have received data from the underlying socket, which | |
924 | * we'll need to parse, process, and respond to appropriately. | |
925 | */ | |
926 | ||
927 | if (p->state == 1) { | |
928 | ||
929 | /* initial response: | |
930 | * version number (1 byte) = 5 | |
931 | * authentication method (1 byte) | |
932 | * authentication methods: | |
933 | * 0x00 = no authentication | |
934 | * 0x01 = GSSAPI | |
935 | * 0x02 = username/password | |
936 | * 0x03 = CHAP | |
937 | * 0xff = no acceptable methods | |
938 | */ | |
939 | char data[2]; | |
940 | ||
941 | if (bufchain_size(&p->pending_input_data) < 2) | |
942 | return 1; /* not got anything yet */ | |
943 | ||
944 | /* get the response */ | |
945 | bufchain_fetch(&p->pending_input_data, data, 2); | |
946 | ||
947 | if (data[0] != 5) { | |
948 | plug_closing(p->plug, "Proxy error: SOCKS proxy returned unexpected version", | |
949 | PROXY_ERROR_GENERAL, 0); | |
950 | return 1; | |
951 | } | |
952 | ||
953 | if (data[1] == 0x00) p->state = 2; /* no authentication needed */ | |
954 | else if (data[1] == 0x01) p->state = 4; /* GSSAPI authentication */ | |
955 | else if (data[1] == 0x02) p->state = 5; /* username/password authentication */ | |
956 | else if (data[1] == 0x03) p->state = 6; /* CHAP authentication */ | |
957 | else { | |
958 | plug_closing(p->plug, "Proxy error: SOCKS proxy did not accept our authentication", | |
959 | PROXY_ERROR_GENERAL, 0); | |
960 | return 1; | |
961 | } | |
962 | bufchain_consume(&p->pending_input_data, 2); | |
963 | } | |
964 | ||
965 | if (p->state == 7) { | |
966 | ||
967 | /* password authentication reply format: | |
968 | * version number (1 bytes) = 1 | |
969 | * reply code (1 byte) | |
970 | * 0 = succeeded | |
971 | * >0 = failed | |
972 | */ | |
973 | char data[2]; | |
974 | ||
975 | if (bufchain_size(&p->pending_input_data) < 2) | |
976 | return 1; /* not got anything yet */ | |
977 | ||
978 | /* get the response */ | |
979 | bufchain_fetch(&p->pending_input_data, data, 2); | |
980 | ||
981 | if (data[0] != 1) { | |
982 | plug_closing(p->plug, "Proxy error: SOCKS password " | |
983 | "subnegotiation contained wrong version number", | |
984 | PROXY_ERROR_GENERAL, 0); | |
985 | return 1; | |
986 | } | |
987 | ||
988 | if (data[1] != 0) { | |
989 | ||
990 | plug_closing(p->plug, "Proxy error: SOCKS proxy refused" | |
991 | " password authentication", | |
992 | PROXY_ERROR_GENERAL, 0); | |
993 | return 1; | |
994 | } | |
995 | ||
996 | bufchain_consume(&p->pending_input_data, 2); | |
997 | p->state = 2; /* now proceed as authenticated */ | |
998 | } | |
999 | ||
1000 | if (p->state == 8) { | |
1001 | int ret; | |
1002 | ret = proxy_socks5_handlechap(p); | |
1003 | if (ret) return ret; | |
1004 | } | |
1005 | ||
1006 | if (p->state == 2) { | |
1007 | ||
1008 | /* request format: | |
1009 | * version number (1 byte) = 5 | |
1010 | * command code (1 byte) | |
1011 | * 1 = CONNECT | |
1012 | * 2 = BIND | |
1013 | * 3 = UDP ASSOCIATE | |
1014 | * reserved (1 byte) = 0x00 | |
1015 | * address type (1 byte) | |
1016 | * 1 = IPv4 | |
1017 | * 3 = domainname (first byte has length, no terminating null) | |
1018 | * 4 = IPv6 | |
1019 | * dest. address (variable) | |
1020 | * dest. port (2 bytes) [network order] | |
1021 | */ | |
1022 | ||
1023 | char command[512]; | |
1024 | int len; | |
1025 | int type; | |
1026 | ||
1027 | type = sk_addrtype(p->remote_addr); | |
1028 | if (type == ADDRTYPE_IPV4) { | |
1029 | len = 10; /* 4 hdr + 4 addr + 2 trailer */ | |
1030 | command[3] = 1; /* IPv4 */ | |
1031 | sk_addrcopy(p->remote_addr, command+4); | |
1032 | } else if (type == ADDRTYPE_IPV6) { | |
1033 | len = 22; /* 4 hdr + 16 addr + 2 trailer */ | |
1034 | command[3] = 4; /* IPv6 */ | |
1035 | sk_addrcopy(p->remote_addr, command+4); | |
1036 | } else { | |
1037 | assert(type == ADDRTYPE_NAME); | |
1038 | command[3] = 3; | |
1039 | sk_getaddr(p->remote_addr, command+5, 256); | |
1040 | command[4] = strlen(command+5); | |
1041 | len = 7 + command[4]; /* 4 hdr, 1 len, N addr, 2 trailer */ | |
1042 | } | |
1043 | ||
1044 | command[0] = 5; /* version 5 */ | |
1045 | command[1] = 1; /* CONNECT command */ | |
1046 | command[2] = 0x00; | |
1047 | ||
1048 | /* port */ | |
1049 | command[len-2] = (char) (p->remote_port >> 8) & 0xff; | |
1050 | command[len-1] = (char) p->remote_port & 0xff; | |
1051 | ||
1052 | sk_write(p->sub_socket, command, len); | |
1053 | ||
1054 | p->state = 3; | |
1055 | return 1; | |
1056 | } | |
1057 | ||
1058 | if (p->state == 3) { | |
1059 | ||
1060 | /* reply format: | |
1061 | * version number (1 bytes) = 5 | |
1062 | * reply code (1 byte) | |
1063 | * 0 = succeeded | |
1064 | * 1 = general SOCKS server failure | |
1065 | * 2 = connection not allowed by ruleset | |
1066 | * 3 = network unreachable | |
1067 | * 4 = host unreachable | |
1068 | * 5 = connection refused | |
1069 | * 6 = TTL expired | |
1070 | * 7 = command not supported | |
1071 | * 8 = address type not supported | |
1072 | * reserved (1 byte) = x00 | |
1073 | * address type (1 byte) | |
1074 | * 1 = IPv4 | |
1075 | * 3 = domainname (first byte has length, no terminating null) | |
1076 | * 4 = IPv6 | |
1077 | * server bound address (variable) | |
1078 | * server bound port (2 bytes) [network order] | |
1079 | */ | |
1080 | char data[5]; | |
1081 | int len; | |
1082 | ||
1083 | /* First 5 bytes of packet are enough to tell its length. */ | |
1084 | if (bufchain_size(&p->pending_input_data) < 5) | |
1085 | return 1; /* not got anything yet */ | |
1086 | ||
1087 | /* get the response */ | |
1088 | bufchain_fetch(&p->pending_input_data, data, 5); | |
1089 | ||
1090 | if (data[0] != 5) { | |
1091 | plug_closing(p->plug, "Proxy error: SOCKS proxy returned wrong version number", | |
1092 | PROXY_ERROR_GENERAL, 0); | |
1093 | return 1; | |
1094 | } | |
1095 | ||
1096 | if (data[1] != 0) { | |
1097 | char buf[256]; | |
1098 | ||
1099 | strcpy(buf, "Proxy error: "); | |
1100 | ||
1101 | switch (data[1]) { | |
1102 | case 1: strcat(buf, "General SOCKS server failure"); break; | |
1103 | case 2: strcat(buf, "Connection not allowed by ruleset"); break; | |
1104 | case 3: strcat(buf, "Network unreachable"); break; | |
1105 | case 4: strcat(buf, "Host unreachable"); break; | |
1106 | case 5: strcat(buf, "Connection refused"); break; | |
1107 | case 6: strcat(buf, "TTL expired"); break; | |
1108 | case 7: strcat(buf, "Command not supported"); break; | |
1109 | case 8: strcat(buf, "Address type not supported"); break; | |
1110 | default: sprintf(buf+strlen(buf), | |
1111 | "Unrecognised SOCKS error code %d", | |
1112 | data[1]); | |
1113 | break; | |
1114 | } | |
1115 | plug_closing(p->plug, buf, PROXY_ERROR_GENERAL, 0); | |
1116 | ||
1117 | return 1; | |
1118 | } | |
1119 | ||
1120 | /* | |
1121 | * Eat the rest of the reply packet. | |
1122 | */ | |
1123 | len = 6; /* first 4 bytes, last 2 */ | |
1124 | switch (data[3]) { | |
1125 | case 1: len += 4; break; /* IPv4 address */ | |
1126 | case 4: len += 16; break;/* IPv6 address */ | |
1127 | case 3: len += (unsigned char)data[4]; break; /* domain name */ | |
1128 | default: | |
1129 | plug_closing(p->plug, "Proxy error: SOCKS proxy returned " | |
1130 | "unrecognised address format", | |
1131 | PROXY_ERROR_GENERAL, 0); | |
1132 | return 1; | |
1133 | } | |
1134 | if (bufchain_size(&p->pending_input_data) < len) | |
1135 | return 1; /* not got whole reply yet */ | |
1136 | bufchain_consume(&p->pending_input_data, len); | |
1137 | ||
1138 | /* we're done */ | |
1139 | proxy_activate(p); | |
1140 | return 1; | |
1141 | } | |
1142 | ||
1143 | if (p->state == 4) { | |
1144 | /* TODO: Handle GSSAPI authentication */ | |
1145 | plug_closing(p->plug, "Proxy error: We don't support GSSAPI authentication", | |
1146 | PROXY_ERROR_GENERAL, 0); | |
1147 | return 1; | |
1148 | } | |
1149 | ||
1150 | if (p->state == 5) { | |
1151 | if (p->cfg.proxy_username[0] || p->cfg.proxy_password[0]) { | |
1152 | char userpwbuf[514]; | |
1153 | int ulen, plen; | |
1154 | ulen = strlen(p->cfg.proxy_username); | |
1155 | if (ulen > 255) ulen = 255; if (ulen < 1) ulen = 1; | |
1156 | plen = strlen(p->cfg.proxy_password); | |
1157 | if (plen > 255) plen = 255; if (plen < 1) plen = 1; | |
1158 | userpwbuf[0] = 1; /* version number of subnegotiation */ | |
1159 | userpwbuf[1] = ulen; | |
1160 | memcpy(userpwbuf+2, p->cfg.proxy_username, ulen); | |
1161 | userpwbuf[ulen+2] = plen; | |
1162 | memcpy(userpwbuf+ulen+3, p->cfg.proxy_password, plen); | |
1163 | sk_write(p->sub_socket, userpwbuf, ulen + plen + 3); | |
1164 | p->state = 7; | |
1165 | } else | |
1166 | plug_closing(p->plug, "Proxy error: Server chose " | |
1167 | "username/password authentication but we " | |
1168 | "didn't offer it!", | |
1169 | PROXY_ERROR_GENERAL, 0); | |
1170 | return 1; | |
1171 | } | |
1172 | ||
1173 | if (p->state == 6) { | |
1174 | int ret; | |
1175 | ret = proxy_socks5_selectchap(p); | |
1176 | if (ret) return ret; | |
1177 | } | |
1178 | ||
1179 | } | |
1180 | ||
1181 | plug_closing(p->plug, "Proxy error: Unexpected proxy error", | |
1182 | PROXY_ERROR_UNEXPECTED, 0); | |
1183 | return 1; | |
1184 | } | |
1185 | ||
1186 | /* ---------------------------------------------------------------------- | |
1187 | * `Telnet' proxy type. | |
1188 | * | |
1189 | * (This is for ad-hoc proxies where you connect to the proxy's | |
1190 | * telnet port and send a command such as `connect host port'. The | |
1191 | * command is configurable, since this proxy type is typically not | |
1192 | * standardised or at all well-defined.) | |
1193 | */ | |
1194 | ||
1195 | char *format_telnet_command(SockAddr addr, int port, const Config *cfg) | |
1196 | { | |
1197 | char *ret = NULL; | |
1198 | int retlen = 0, retsize = 0; | |
1199 | int so = 0, eo = 0; | |
1200 | #define ENSURE(n) do { \ | |
1201 | if (retsize < retlen + n) { \ | |
1202 | retsize = retlen + n + 512; \ | |
1203 | ret = sresize(ret, retsize, char); \ | |
1204 | } \ | |
1205 | } while (0) | |
1206 | ||
1207 | /* we need to escape \\, \%, \r, \n, \t, \x??, \0???, | |
1208 | * %%, %host, %port, %user, and %pass | |
1209 | */ | |
1210 | ||
1211 | while (cfg->proxy_telnet_command[eo] != 0) { | |
1212 | ||
1213 | /* scan forward until we hit end-of-line, | |
1214 | * or an escape character (\ or %) */ | |
1215 | while (cfg->proxy_telnet_command[eo] != 0 && | |
1216 | cfg->proxy_telnet_command[eo] != '%' && | |
1217 | cfg->proxy_telnet_command[eo] != '\\') eo++; | |
1218 | ||
1219 | /* if we hit eol, break out of our escaping loop */ | |
1220 | if (cfg->proxy_telnet_command[eo] == 0) break; | |
1221 | ||
1222 | /* if there was any unescaped text before the escape | |
1223 | * character, send that now */ | |
1224 | if (eo != so) { | |
1225 | ENSURE(eo - so); | |
1226 | memcpy(ret + retlen, cfg->proxy_telnet_command + so, eo - so); | |
1227 | retlen += eo - so; | |
1228 | } | |
1229 | ||
1230 | so = eo++; | |
1231 | ||
1232 | /* if the escape character was the last character of | |
1233 | * the line, we'll just stop and send it. */ | |
1234 | if (cfg->proxy_telnet_command[eo] == 0) break; | |
1235 | ||
1236 | if (cfg->proxy_telnet_command[so] == '\\') { | |
1237 | ||
1238 | /* we recognize \\, \%, \r, \n, \t, \x??. | |
1239 | * anything else, we just send unescaped (including the \). | |
1240 | */ | |
1241 | ||
1242 | switch (cfg->proxy_telnet_command[eo]) { | |
1243 | ||
1244 | case '\\': | |
1245 | ENSURE(1); | |
1246 | ret[retlen++] = '\\'; | |
1247 | eo++; | |
1248 | break; | |
1249 | ||
1250 | case '%': | |
1251 | ENSURE(1); | |
1252 | ret[retlen++] = '%'; | |
1253 | eo++; | |
1254 | break; | |
1255 | ||
1256 | case 'r': | |
1257 | ENSURE(1); | |
1258 | ret[retlen++] = '\r'; | |
1259 | eo++; | |
1260 | break; | |
1261 | ||
1262 | case 'n': | |
1263 | ENSURE(1); | |
1264 | ret[retlen++] = '\n'; | |
1265 | eo++; | |
1266 | break; | |
1267 | ||
1268 | case 't': | |
1269 | ENSURE(1); | |
1270 | ret[retlen++] = '\t'; | |
1271 | eo++; | |
1272 | break; | |
1273 | ||
1274 | case 'x': | |
1275 | case 'X': | |
1276 | { | |
1277 | /* escaped hexadecimal value (ie. \xff) */ | |
1278 | unsigned char v = 0; | |
1279 | int i = 0; | |
1280 | ||
1281 | for (;;) { | |
1282 | eo++; | |
1283 | if (cfg->proxy_telnet_command[eo] >= '0' && | |
1284 | cfg->proxy_telnet_command[eo] <= '9') | |
1285 | v += cfg->proxy_telnet_command[eo] - '0'; | |
1286 | else if (cfg->proxy_telnet_command[eo] >= 'a' && | |
1287 | cfg->proxy_telnet_command[eo] <= 'f') | |
1288 | v += cfg->proxy_telnet_command[eo] - 'a' + 10; | |
1289 | else if (cfg->proxy_telnet_command[eo] >= 'A' && | |
1290 | cfg->proxy_telnet_command[eo] <= 'F') | |
1291 | v += cfg->proxy_telnet_command[eo] - 'A' + 10; | |
1292 | else { | |
1293 | /* non hex character, so we abort and just | |
1294 | * send the whole thing unescaped (including \x) | |
1295 | */ | |
1296 | ENSURE(1); | |
1297 | ret[retlen++] = '\\'; | |
1298 | eo = so + 1; | |
1299 | break; | |
1300 | } | |
1301 | ||
1302 | /* we only extract two hex characters */ | |
1303 | if (i == 1) { | |
1304 | ENSURE(1); | |
1305 | ret[retlen++] = v; | |
1306 | eo++; | |
1307 | break; | |
1308 | } | |
1309 | ||
1310 | i++; | |
1311 | v <<= 4; | |
1312 | } | |
1313 | } | |
1314 | break; | |
1315 | ||
1316 | default: | |
1317 | ENSURE(2); | |
1318 | memcpy(ret+retlen, cfg->proxy_telnet_command + so, 2); | |
1319 | retlen += 2; | |
1320 | eo++; | |
1321 | break; | |
1322 | } | |
1323 | } else { | |
1324 | ||
1325 | /* % escape. we recognize %%, %host, %port, %user, %pass. | |
1326 | * %proxyhost, %proxyport. Anything else we just send | |
1327 | * unescaped (including the %). | |
1328 | */ | |
1329 | ||
1330 | if (cfg->proxy_telnet_command[eo] == '%') { | |
1331 | ENSURE(1); | |
1332 | ret[retlen++] = '%'; | |
1333 | eo++; | |
1334 | } | |
1335 | else if (strnicmp(cfg->proxy_telnet_command + eo, | |
1336 | "host", 4) == 0) { | |
1337 | char dest[512]; | |
1338 | int destlen; | |
1339 | sk_getaddr(addr, dest, lenof(dest)); | |
1340 | destlen = strlen(dest); | |
1341 | ENSURE(destlen); | |
1342 | memcpy(ret+retlen, dest, destlen); | |
1343 | retlen += destlen; | |
1344 | eo += 4; | |
1345 | } | |
1346 | else if (strnicmp(cfg->proxy_telnet_command + eo, | |
1347 | "port", 4) == 0) { | |
1348 | char portstr[8], portlen; | |
1349 | portlen = sprintf(portstr, "%i", port); | |
1350 | ENSURE(portlen); | |
1351 | memcpy(ret + retlen, portstr, portlen); | |
1352 | retlen += portlen; | |
1353 | eo += 4; | |
1354 | } | |
1355 | else if (strnicmp(cfg->proxy_telnet_command + eo, | |
1356 | "user", 4) == 0) { | |
1357 | int userlen = strlen(cfg->proxy_username); | |
1358 | ENSURE(userlen); | |
1359 | memcpy(ret+retlen, cfg->proxy_username, userlen); | |
1360 | retlen += userlen; | |
1361 | eo += 4; | |
1362 | } | |
1363 | else if (strnicmp(cfg->proxy_telnet_command + eo, | |
1364 | "pass", 4) == 0) { | |
1365 | int passlen = strlen(cfg->proxy_password); | |
1366 | ENSURE(passlen); | |
1367 | memcpy(ret+retlen, cfg->proxy_password, passlen); | |
1368 | retlen += passlen; | |
1369 | eo += 4; | |
1370 | } | |
1371 | else if (strnicmp(cfg->proxy_telnet_command + eo, | |
1372 | "proxyhost", 9) == 0) { | |
1373 | int phlen = strlen(cfg->proxy_host); | |
1374 | ENSURE(phlen); | |
1375 | memcpy(ret+retlen, cfg->proxy_host, phlen); | |
1376 | retlen += phlen; | |
1377 | eo += 9; | |
1378 | } | |
1379 | else if (strnicmp(cfg->proxy_telnet_command + eo, | |
1380 | "proxyport", 9) == 0) { | |
1381 | char pport[50]; | |
1382 | int pplen; | |
1383 | sprintf(pport, "%d", cfg->proxy_port); | |
1384 | pplen = strlen(pport); | |
1385 | ENSURE(pplen); | |
1386 | memcpy(ret+retlen, pport, pplen); | |
1387 | retlen += pplen; | |
1388 | eo += 9; | |
1389 | } | |
1390 | else { | |
1391 | /* we don't escape this, so send the % now, and | |
1392 | * don't advance eo, so that we'll consider the | |
1393 | * text immediately following the % as unescaped. | |
1394 | */ | |
1395 | ENSURE(1); | |
1396 | ret[retlen++] = '%'; | |
1397 | } | |
1398 | } | |
1399 | ||
1400 | /* resume scanning for additional escapes after this one. */ | |
1401 | so = eo; | |
1402 | } | |
1403 | ||
1404 | /* if there is any unescaped text at the end of the line, send it */ | |
1405 | if (eo != so) { | |
1406 | ENSURE(eo - so); | |
1407 | memcpy(ret + retlen, cfg->proxy_telnet_command + so, eo - so); | |
1408 | retlen += eo - so; | |
1409 | } | |
1410 | ||
1411 | ENSURE(1); | |
1412 | ret[retlen] = '\0'; | |
1413 | return ret; | |
1414 | ||
1415 | #undef ENSURE | |
1416 | } | |
1417 | ||
1418 | int proxy_telnet_negotiate (Proxy_Socket p, int change) | |
1419 | { | |
1420 | if (p->state == PROXY_CHANGE_NEW) { | |
1421 | char *formatted_cmd; | |
1422 | ||
1423 | formatted_cmd = format_telnet_command(p->remote_addr, p->remote_port, | |
1424 | &p->cfg); | |
1425 | ||
1426 | sk_write(p->sub_socket, formatted_cmd, strlen(formatted_cmd)); | |
1427 | sfree(formatted_cmd); | |
1428 | ||
1429 | p->state = 1; | |
1430 | return 0; | |
1431 | } | |
1432 | ||
1433 | if (change == PROXY_CHANGE_CLOSING) { | |
1434 | /* if our proxy negotiation process involves closing and opening | |
1435 | * new sockets, then we would want to intercept this closing | |
1436 | * callback when we were expecting it. if we aren't anticipating | |
1437 | * a socket close, then some error must have occurred. we'll | |
1438 | * just pass those errors up to the backend. | |
1439 | */ | |
1440 | return plug_closing(p->plug, p->closing_error_msg, | |
1441 | p->closing_error_code, | |
1442 | p->closing_calling_back); | |
1443 | } | |
1444 | ||
1445 | if (change == PROXY_CHANGE_SENT) { | |
1446 | /* some (or all) of what we wrote to the proxy was sent. | |
1447 | * we don't do anything new, however, until we receive the | |
1448 | * proxy's response. we might want to set a timer so we can | |
1449 | * timeout the proxy negotiation after a while... | |
1450 | */ | |
1451 | return 0; | |
1452 | } | |
1453 | ||
1454 | if (change == PROXY_CHANGE_ACCEPTING) { | |
1455 | /* we should _never_ see this, as we are using our socket to | |
1456 | * connect to a proxy, not accepting inbound connections. | |
1457 | * what should we do? close the socket with an appropriate | |
1458 | * error message? | |
1459 | */ | |
1460 | return plug_accepting(p->plug, p->accepting_sock); | |
1461 | } | |
1462 | ||
1463 | if (change == PROXY_CHANGE_RECEIVE) { | |
1464 | /* we have received data from the underlying socket, which | |
1465 | * we'll need to parse, process, and respond to appropriately. | |
1466 | */ | |
1467 | ||
1468 | /* we're done */ | |
1469 | proxy_activate(p); | |
1470 | /* proxy activate will have dealt with | |
1471 | * whatever is left of the buffer */ | |
1472 | return 1; | |
1473 | } | |
1474 | ||
1475 | plug_closing(p->plug, "Proxy error: Unexpected proxy error", | |
1476 | PROXY_ERROR_UNEXPECTED, 0); | |
1477 | return 1; | |
1478 | } |