1 /***************************************************************************
2 * _ _ ____ _
3 * Project ___| | | | _ \| |
4 * / __| | | | |_) | |
5 * | (__| |_| | _ <| |___
6 * \___|\___/|_| \_\_____|
7 *
8 * Copyright (C) 1998 - 2020, Daniel Stenberg, <daniel@haxx.se>, et al.
9 *
10 * This software is licensed as described in the file COPYING, which
11 * you should have received as part of this distribution. The terms
12 * are also available at https://curl.haxx.se/docs/copyright.html.
13 *
14 * You may opt to use, copy, modify, merge, publish, distribute and/or sell
15 * copies of the Software, and permit persons to whom the Software is
16 * furnished to do so, under the terms of the COPYING file.
17 *
18 * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
19 * KIND, either express or implied.
20 *
21 ***************************************************************************/
22
23 #include "curl_setup.h"
24
25 #if !defined(CURL_DISABLE_PROXY)
26
27 #ifdef HAVE_NETINET_IN_H
28 #include <netinet/in.h>
29 #endif
30 #ifdef HAVE_ARPA_INET_H
31 #include <arpa/inet.h>
32 #endif
33
34 #include "urldata.h"
35 #include "sendf.h"
36 #include "select.h"
37 #include "connect.h"
38 #include "timeval.h"
39 #include "socks.h"
40 #include "multiif.h" /* for getsock macros */
41
42 /* The last 3 #include files should be in this order */
43 #include "curl_printf.h"
44 #include "curl_memory.h"
45 #include "memdebug.h"
46
47 #if defined(HAVE_GSSAPI) || defined(USE_WINDOWS_SSPI)
48 /*
49 * Helper read-from-socket functions. Does the same as Curl_read() but it
50 * blocks until all bytes amount of buffersize will be read. No more, no less.
51 *
52 * This is STUPID BLOCKING behavior. Only used by the SOCKS GSSAPI functions.
53 */
Curl_blockread_all(struct connectdata * conn,curl_socket_t sockfd,char * buf,ssize_t buffersize,ssize_t * n)54 int Curl_blockread_all(struct connectdata *conn, /* connection data */
55 curl_socket_t sockfd, /* read from this socket */
56 char *buf, /* store read data here */
57 ssize_t buffersize, /* max amount to read */
58 ssize_t *n) /* amount bytes read */
59 {
60 ssize_t nread = 0;
61 ssize_t allread = 0;
62 int result;
63 *n = 0;
64 for(;;) {
65 timediff_t timeout_ms = Curl_timeleft(conn->data, NULL, TRUE);
66 if(timeout_ms < 0) {
67 /* we already got the timeout */
68 result = CURLE_OPERATION_TIMEDOUT;
69 break;
70 }
71 if(!timeout_ms)
72 timeout_ms = TIMEDIFF_T_MAX;
73 if(SOCKET_READABLE(sockfd, timeout_ms) <= 0) {
74 result = ~CURLE_OK;
75 break;
76 }
77 result = Curl_read_plain(sockfd, buf, buffersize, &nread);
78 if(CURLE_AGAIN == result)
79 continue;
80 if(result)
81 break;
82
83 if(buffersize == nread) {
84 allread += nread;
85 *n = allread;
86 result = CURLE_OK;
87 break;
88 }
89 if(!nread) {
90 result = ~CURLE_OK;
91 break;
92 }
93
94 buffersize -= nread;
95 buf += nread;
96 allread += nread;
97 }
98 return result;
99 }
100 #endif
101
102 #ifndef DEBUGBUILD
103 #define sxstate(x,y) socksstate(x,y)
104 #else
105 #define sxstate(x,y) socksstate(x,y, __LINE__)
106 #endif
107
108
109 /* always use this function to change state, to make debugging easier */
socksstate(struct connectdata * conn,enum connect_t state,int lineno)110 static void socksstate(struct connectdata *conn,
111 enum connect_t state
112 #ifdef DEBUGBUILD
113 , int lineno
114 #endif
115 )
116 {
117 enum connect_t oldstate = conn->cnnct.state;
118 #if defined(DEBUGBUILD) && !defined(CURL_DISABLE_VERBOSE_STRINGS)
119 /* synced with the state list in urldata.h */
120 static const char * const statename[] = {
121 "INIT",
122 "SOCKS_INIT",
123 "SOCKS_SEND",
124 "SOCKS_READ_INIT",
125 "SOCKS_READ",
126 "GSSAPI_INIT",
127 "AUTH_INIT",
128 "AUTH_SEND",
129 "AUTH_READ",
130 "REQ_INIT",
131 "RESOLVING",
132 "RESOLVED",
133 "RESOLVE_REMOTE",
134 "REQ_SEND",
135 "REQ_SENDING",
136 "REQ_READ",
137 "REQ_READ_MORE",
138 "DONE"
139 };
140 #endif
141
142 if(oldstate == state)
143 /* don't bother when the new state is the same as the old state */
144 return;
145
146 conn->cnnct.state = state;
147
148 #if defined(DEBUGBUILD) && !defined(CURL_DISABLE_VERBOSE_STRINGS)
149 infof(conn->data,
150 "SXSTATE: %s => %s conn %p; line %d\n",
151 statename[oldstate], statename[conn->cnnct.state], conn,
152 lineno);
153 #endif
154 }
155
Curl_SOCKS_getsock(struct connectdata * conn,curl_socket_t * sock,int sockindex)156 int Curl_SOCKS_getsock(struct connectdata *conn, curl_socket_t *sock,
157 int sockindex)
158 {
159 int rc = 0;
160 sock[0] = conn->sock[sockindex];
161 switch(conn->cnnct.state) {
162 case CONNECT_RESOLVING:
163 case CONNECT_SOCKS_READ:
164 case CONNECT_AUTH_READ:
165 case CONNECT_REQ_READ:
166 case CONNECT_REQ_READ_MORE:
167 rc = GETSOCK_READSOCK(0);
168 break;
169 default:
170 rc = GETSOCK_WRITESOCK(0);
171 break;
172 }
173 return rc;
174 }
175
176 /*
177 * This function logs in to a SOCKS4 proxy and sends the specifics to the final
178 * destination server.
179 *
180 * Reference :
181 * https://www.openssh.com/txt/socks4.protocol
182 *
183 * Note :
184 * Set protocol4a=true for "SOCKS 4A (Simple Extension to SOCKS 4 Protocol)"
185 * Nonsupport "Identification Protocol (RFC1413)"
186 */
Curl_SOCKS4(const char * proxy_user,const char * hostname,int remote_port,int sockindex,struct connectdata * conn,bool * done)187 CURLproxycode Curl_SOCKS4(const char *proxy_user,
188 const char *hostname,
189 int remote_port,
190 int sockindex,
191 struct connectdata *conn,
192 bool *done)
193 {
194 const bool protocol4a =
195 (conn->socks_proxy.proxytype == CURLPROXY_SOCKS4A) ? TRUE : FALSE;
196 unsigned char *socksreq = &conn->cnnct.socksreq[0];
197 CURLcode result;
198 curl_socket_t sockfd = conn->sock[sockindex];
199 struct Curl_easy *data = conn->data;
200 struct connstate *sx = &conn->cnnct;
201 struct Curl_dns_entry *dns = NULL;
202 ssize_t actualread;
203 ssize_t written;
204
205 if(!SOCKS_STATE(sx->state) && !*done)
206 sxstate(conn, CONNECT_SOCKS_INIT);
207
208 switch(sx->state) {
209 case CONNECT_SOCKS_INIT:
210 /* SOCKS4 can only do IPv4, insist! */
211 conn->ip_version = CURL_IPRESOLVE_V4;
212 if(conn->bits.httpproxy)
213 infof(conn->data, "SOCKS4%s: connecting to HTTP proxy %s port %d\n",
214 protocol4a ? "a" : "", hostname, remote_port);
215
216 infof(data, "SOCKS4 communication to %s:%d\n", hostname, remote_port);
217
218 /*
219 * Compose socks4 request
220 *
221 * Request format
222 *
223 * +----+----+----+----+----+----+----+----+----+----+....+----+
224 * | VN | CD | DSTPORT | DSTIP | USERID |NULL|
225 * +----+----+----+----+----+----+----+----+----+----+....+----+
226 * # of bytes: 1 1 2 4 variable 1
227 */
228
229 socksreq[0] = 4; /* version (SOCKS4) */
230 socksreq[1] = 1; /* connect */
231 socksreq[2] = (unsigned char)((remote_port >> 8) & 0xff); /* PORT MSB */
232 socksreq[3] = (unsigned char)(remote_port & 0xff); /* PORT LSB */
233
234 /* DNS resolve only for SOCKS4, not SOCKS4a */
235 if(!protocol4a) {
236 enum resolve_t rc =
237 Curl_resolv(conn, hostname, remote_port, FALSE, &dns);
238
239 if(rc == CURLRESOLV_ERROR)
240 return CURLPX_RESOLVE_HOST;
241 else if(rc == CURLRESOLV_PENDING) {
242 sxstate(conn, CONNECT_RESOLVING);
243 infof(data, "SOCKS4 non-blocking resolve of %s\n", hostname);
244 return CURLPX_OK;
245 }
246 sxstate(conn, CONNECT_RESOLVED);
247 goto CONNECT_RESOLVED;
248 }
249
250 /* socks4a doesn't resolve anything locally */
251 sxstate(conn, CONNECT_REQ_INIT);
252 goto CONNECT_REQ_INIT;
253
254 case CONNECT_RESOLVING:
255 /* check if we have the name resolved by now */
256 dns = Curl_fetch_addr(conn, hostname, (int)conn->port);
257
258 if(dns) {
259 #ifdef CURLRES_ASYNCH
260 conn->async.dns = dns;
261 conn->async.done = TRUE;
262 #endif
263 infof(data, "Hostname '%s' was found\n", hostname);
264 sxstate(conn, CONNECT_RESOLVED);
265 }
266 else {
267 result = Curl_resolv_check(data->conn, &dns);
268 if(!dns) {
269 if(result)
270 return CURLPX_RESOLVE_HOST;
271 return CURLPX_OK;
272 }
273 }
274 /* FALLTHROUGH */
275 CONNECT_RESOLVED:
276 case CONNECT_RESOLVED: {
277 struct Curl_addrinfo *hp = NULL;
278 char buf[64];
279 /*
280 * We cannot use 'hostent' as a struct that Curl_resolv() returns. It
281 * returns a Curl_addrinfo pointer that may not always look the same.
282 */
283 if(dns)
284 hp = dns->addr;
285 if(hp) {
286 Curl_printable_address(hp, buf, sizeof(buf));
287
288 if(hp->ai_family == AF_INET) {
289 struct sockaddr_in *saddr_in;
290
291 saddr_in = (struct sockaddr_in *)(void *)hp->ai_addr;
292 socksreq[4] = ((unsigned char *)&saddr_in->sin_addr.s_addr)[0];
293 socksreq[5] = ((unsigned char *)&saddr_in->sin_addr.s_addr)[1];
294 socksreq[6] = ((unsigned char *)&saddr_in->sin_addr.s_addr)[2];
295 socksreq[7] = ((unsigned char *)&saddr_in->sin_addr.s_addr)[3];
296
297 infof(data, "SOCKS4 connect to IPv4 %s (locally resolved)\n", buf);
298 }
299 else {
300 hp = NULL; /* fail! */
301 failf(data, "SOCKS4 connection to %s not supported\n", buf);
302 }
303
304 Curl_resolv_unlock(data, dns); /* not used anymore from now on */
305 }
306 if(!hp) {
307 failf(data, "Failed to resolve \"%s\" for SOCKS4 connect.",
308 hostname);
309 return CURLPX_RESOLVE_HOST;
310 }
311 }
312 /* FALLTHROUGH */
313 CONNECT_REQ_INIT:
314 case CONNECT_REQ_INIT:
315 /*
316 * This is currently not supporting "Identification Protocol (RFC1413)".
317 */
318 socksreq[8] = 0; /* ensure empty userid is NUL-terminated */
319 if(proxy_user) {
320 size_t plen = strlen(proxy_user);
321 if(plen >= sizeof(sx->socksreq) - 8) {
322 failf(data, "Too long SOCKS proxy user name, can't use!\n");
323 return CURLPX_LONG_USER;
324 }
325 /* copy the proxy name WITH trailing zero */
326 memcpy(socksreq + 8, proxy_user, plen + 1);
327 }
328
329 /*
330 * Make connection
331 */
332 {
333 size_t packetsize = 9 +
334 strlen((char *)socksreq + 8); /* size including NUL */
335
336 /* If SOCKS4a, set special invalid IP address 0.0.0.x */
337 if(protocol4a) {
338 size_t hostnamelen = 0;
339 socksreq[4] = 0;
340 socksreq[5] = 0;
341 socksreq[6] = 0;
342 socksreq[7] = 1;
343 /* append hostname */
344 hostnamelen = strlen(hostname) + 1; /* length including NUL */
345 if(hostnamelen <= 255)
346 strcpy((char *)socksreq + packetsize, hostname);
347 else {
348 failf(data, "SOCKS4: too long host name");
349 return CURLPX_LONG_HOSTNAME;
350 }
351 packetsize += hostnamelen;
352 }
353 sx->outp = socksreq;
354 sx->outstanding = packetsize;
355 sxstate(conn, CONNECT_REQ_SENDING);
356 }
357 /* FALLTHROUGH */
358 case CONNECT_REQ_SENDING:
359 /* Send request */
360 result = Curl_write_plain(conn, sockfd, (char *)sx->outp,
361 sx->outstanding, &written);
362 if(result && (CURLE_AGAIN != result)) {
363 failf(data, "Failed to send SOCKS4 connect request.");
364 return CURLPX_SEND_CONNECT;
365 }
366 if(written != sx->outstanding) {
367 /* not done, remain in state */
368 sx->outstanding -= written;
369 sx->outp += written;
370 return CURLPX_OK;
371 }
372
373 /* done sending! */
374 sx->outstanding = 8; /* receive data size */
375 sx->outp = socksreq;
376 sxstate(conn, CONNECT_SOCKS_READ);
377
378 /* FALLTHROUGH */
379 case CONNECT_SOCKS_READ:
380 /* Receive response */
381 result = Curl_read_plain(sockfd, (char *)sx->outp,
382 sx->outstanding, &actualread);
383 if(result && (CURLE_AGAIN != result)) {
384 failf(data, "SOCKS4: Failed receiving connect request ack: %s",
385 curl_easy_strerror(result));
386 return CURLPX_RECV_CONNECT;
387 }
388 else if(!result && !actualread) {
389 /* connection closed */
390 failf(data, "connection to proxy closed");
391 return CURLPX_CLOSED;
392 }
393 else if(actualread != sx->outstanding) {
394 /* remain in reading state */
395 sx->outstanding -= actualread;
396 sx->outp += actualread;
397 return CURLPX_OK;
398 }
399 sxstate(conn, CONNECT_DONE);
400 break;
401 default: /* lots of unused states in SOCKS4 */
402 break;
403 }
404
405 /*
406 * Response format
407 *
408 * +----+----+----+----+----+----+----+----+
409 * | VN | CD | DSTPORT | DSTIP |
410 * +----+----+----+----+----+----+----+----+
411 * # of bytes: 1 1 2 4
412 *
413 * VN is the version of the reply code and should be 0. CD is the result
414 * code with one of the following values:
415 *
416 * 90: request granted
417 * 91: request rejected or failed
418 * 92: request rejected because SOCKS server cannot connect to
419 * identd on the client
420 * 93: request rejected because the client program and identd
421 * report different user-ids
422 */
423
424 /* wrong version ? */
425 if(socksreq[0] != 0) {
426 failf(data,
427 "SOCKS4 reply has wrong version, version should be 0.");
428 return CURLPX_BAD_VERSION;
429 }
430
431 /* Result */
432 switch(socksreq[1]) {
433 case 90:
434 infof(data, "SOCKS4%s request granted.\n", protocol4a?"a":"");
435 break;
436 case 91:
437 failf(data,
438 "Can't complete SOCKS4 connection to %d.%d.%d.%d:%d. (%d)"
439 ", request rejected or failed.",
440 (unsigned char)socksreq[4], (unsigned char)socksreq[5],
441 (unsigned char)socksreq[6], (unsigned char)socksreq[7],
442 (((unsigned char)socksreq[2] << 8) | (unsigned char)socksreq[3]),
443 (unsigned char)socksreq[1]);
444 return CURLPX_REQUEST_FAILED;
445 case 92:
446 failf(data,
447 "Can't complete SOCKS4 connection to %d.%d.%d.%d:%d. (%d)"
448 ", request rejected because SOCKS server cannot connect to "
449 "identd on the client.",
450 (unsigned char)socksreq[4], (unsigned char)socksreq[5],
451 (unsigned char)socksreq[6], (unsigned char)socksreq[7],
452 (((unsigned char)socksreq[2] << 8) | (unsigned char)socksreq[3]),
453 (unsigned char)socksreq[1]);
454 return CURLPX_IDENTD;
455 case 93:
456 failf(data,
457 "Can't complete SOCKS4 connection to %d.%d.%d.%d:%d. (%d)"
458 ", request rejected because the client program and identd "
459 "report different user-ids.",
460 (unsigned char)socksreq[4], (unsigned char)socksreq[5],
461 (unsigned char)socksreq[6], (unsigned char)socksreq[7],
462 (((unsigned char)socksreq[2] << 8) | (unsigned char)socksreq[3]),
463 (unsigned char)socksreq[1]);
464 return CURLPX_IDENTD_DIFFER;
465 default:
466 failf(data,
467 "Can't complete SOCKS4 connection to %d.%d.%d.%d:%d. (%d)"
468 ", Unknown.",
469 (unsigned char)socksreq[4], (unsigned char)socksreq[5],
470 (unsigned char)socksreq[6], (unsigned char)socksreq[7],
471 (((unsigned char)socksreq[2] << 8) | (unsigned char)socksreq[3]),
472 (unsigned char)socksreq[1]);
473 return CURLPX_UNKNOWN_FAIL;
474 }
475
476 *done = TRUE;
477 return CURLPX_OK; /* Proxy was successful! */
478 }
479
480 /*
481 * This function logs in to a SOCKS5 proxy and sends the specifics to the final
482 * destination server.
483 */
Curl_SOCKS5(const char * proxy_user,const char * proxy_password,const char * hostname,int remote_port,int sockindex,struct connectdata * conn,bool * done)484 CURLproxycode Curl_SOCKS5(const char *proxy_user,
485 const char *proxy_password,
486 const char *hostname,
487 int remote_port,
488 int sockindex,
489 struct connectdata *conn,
490 bool *done)
491 {
492 /*
493 According to the RFC1928, section "6. Replies". This is what a SOCK5
494 replies:
495
496 +----+-----+-------+------+----------+----------+
497 |VER | REP | RSV | ATYP | BND.ADDR | BND.PORT |
498 +----+-----+-------+------+----------+----------+
499 | 1 | 1 | X'00' | 1 | Variable | 2 |
500 +----+-----+-------+------+----------+----------+
501
502 Where:
503
504 o VER protocol version: X'05'
505 o REP Reply field:
506 o X'00' succeeded
507 */
508 unsigned char *socksreq = &conn->cnnct.socksreq[0];
509 char dest[256] = "unknown"; /* printable hostname:port */
510 int idx;
511 ssize_t actualread;
512 ssize_t written;
513 CURLcode result;
514 curl_socket_t sockfd = conn->sock[sockindex];
515 struct Curl_easy *data = conn->data;
516 bool socks5_resolve_local =
517 (conn->socks_proxy.proxytype == CURLPROXY_SOCKS5) ? TRUE : FALSE;
518 const size_t hostname_len = strlen(hostname);
519 ssize_t len = 0;
520 const unsigned long auth = data->set.socks5auth;
521 bool allow_gssapi = FALSE;
522 struct connstate *sx = &conn->cnnct;
523 struct Curl_dns_entry *dns = NULL;
524
525 if(!SOCKS_STATE(sx->state) && !*done)
526 sxstate(conn, CONNECT_SOCKS_INIT);
527
528 switch(sx->state) {
529 case CONNECT_SOCKS_INIT:
530 if(conn->bits.httpproxy)
531 infof(conn->data, "SOCKS5: connecting to HTTP proxy %s port %d\n",
532 hostname, remote_port);
533
534 /* RFC1928 chapter 5 specifies max 255 chars for domain name in packet */
535 if(!socks5_resolve_local && hostname_len > 255) {
536 infof(conn->data, "SOCKS5: server resolving disabled for hostnames of "
537 "length > 255 [actual len=%zu]\n", hostname_len);
538 socks5_resolve_local = TRUE;
539 }
540
541 if(auth & ~(CURLAUTH_BASIC | CURLAUTH_GSSAPI))
542 infof(conn->data,
543 "warning: unsupported value passed to CURLOPT_SOCKS5_AUTH: %lu\n",
544 auth);
545 if(!(auth & CURLAUTH_BASIC))
546 /* disable username/password auth */
547 proxy_user = NULL;
548 #if defined(HAVE_GSSAPI) || defined(USE_WINDOWS_SSPI)
549 if(auth & CURLAUTH_GSSAPI)
550 allow_gssapi = TRUE;
551 #endif
552
553 idx = 0;
554 socksreq[idx++] = 5; /* version */
555 idx++; /* number of authentication methods */
556 socksreq[idx++] = 0; /* no authentication */
557 if(allow_gssapi)
558 socksreq[idx++] = 1; /* GSS-API */
559 if(proxy_user)
560 socksreq[idx++] = 2; /* username/password */
561 /* write the number of authentication methods */
562 socksreq[1] = (unsigned char) (idx - 2);
563
564 result = Curl_write_plain(conn, sockfd, (char *)socksreq, idx, &written);
565 if(result && (CURLE_AGAIN != result)) {
566 failf(data, "Unable to send initial SOCKS5 request.");
567 return CURLPX_SEND_CONNECT;
568 }
569 if(written != idx) {
570 sxstate(conn, CONNECT_SOCKS_SEND);
571 sx->outstanding = idx - written;
572 sx->outp = &socksreq[written];
573 return CURLPX_OK;
574 }
575 sxstate(conn, CONNECT_SOCKS_READ);
576 goto CONNECT_SOCKS_READ_INIT;
577 case CONNECT_SOCKS_SEND:
578 result = Curl_write_plain(conn, sockfd, (char *)sx->outp,
579 sx->outstanding, &written);
580 if(result && (CURLE_AGAIN != result)) {
581 failf(data, "Unable to send initial SOCKS5 request.");
582 return CURLPX_SEND_CONNECT;
583 }
584 if(written != sx->outstanding) {
585 /* not done, remain in state */
586 sx->outstanding -= written;
587 sx->outp += written;
588 return CURLPX_OK;
589 }
590 /* FALLTHROUGH */
591 CONNECT_SOCKS_READ_INIT:
592 case CONNECT_SOCKS_READ_INIT:
593 sx->outstanding = 2; /* expect two bytes */
594 sx->outp = socksreq; /* store it here */
595 /* FALLTHROUGH */
596 case CONNECT_SOCKS_READ:
597 result = Curl_read_plain(sockfd, (char *)sx->outp,
598 sx->outstanding, &actualread);
599 if(result && (CURLE_AGAIN != result)) {
600 failf(data, "Unable to receive initial SOCKS5 response.");
601 return CURLPX_RECV_CONNECT;
602 }
603 else if(!result && !actualread) {
604 /* connection closed */
605 failf(data, "Connection to proxy closed");
606 return CURLPX_CLOSED;
607 }
608 else if(actualread != sx->outstanding) {
609 /* remain in reading state */
610 sx->outstanding -= actualread;
611 sx->outp += actualread;
612 return CURLPX_OK;
613 }
614 else if(socksreq[0] != 5) {
615 failf(data, "Received invalid version in initial SOCKS5 response.");
616 return CURLPX_BAD_VERSION;
617 }
618 else if(socksreq[1] == 0) {
619 /* DONE! No authentication needed. Send request. */
620 sxstate(conn, CONNECT_REQ_INIT);
621 goto CONNECT_REQ_INIT;
622 }
623 else if(socksreq[1] == 2) {
624 /* regular name + password authentication */
625 sxstate(conn, CONNECT_AUTH_INIT);
626 goto CONNECT_AUTH_INIT;
627 }
628 #if defined(HAVE_GSSAPI) || defined(USE_WINDOWS_SSPI)
629 else if(allow_gssapi && (socksreq[1] == 1)) {
630 sxstate(conn, CONNECT_GSSAPI_INIT);
631 result = Curl_SOCKS5_gssapi_negotiate(sockindex, conn);
632 if(result) {
633 failf(data, "Unable to negotiate SOCKS5 GSS-API context.");
634 return CURLPX_GSSAPI;
635 }
636 }
637 #endif
638 else {
639 /* error */
640 if(!allow_gssapi && (socksreq[1] == 1)) {
641 failf(data,
642 "SOCKS5 GSSAPI per-message authentication is not supported.");
643 return CURLPX_GSSAPI_PERMSG;
644 }
645 else if(socksreq[1] == 255) {
646 failf(data, "No authentication method was acceptable.");
647 return CURLPX_NO_AUTH;
648 }
649 }
650 failf(data,
651 "Undocumented SOCKS5 mode attempted to be used by server.");
652 return CURLPX_UNKNOWN_MODE;
653 #if defined(HAVE_GSSAPI) || defined(USE_WINDOWS_SSPI)
654 case CONNECT_GSSAPI_INIT:
655 /* GSSAPI stuff done non-blocking */
656 break;
657 #endif
658
659 default: /* do nothing! */
660 break;
661
662 CONNECT_AUTH_INIT:
663 case CONNECT_AUTH_INIT: {
664 /* Needs user name and password */
665 size_t proxy_user_len, proxy_password_len;
666 if(proxy_user && proxy_password) {
667 proxy_user_len = strlen(proxy_user);
668 proxy_password_len = strlen(proxy_password);
669 }
670 else {
671 proxy_user_len = 0;
672 proxy_password_len = 0;
673 }
674
675 /* username/password request looks like
676 * +----+------+----------+------+----------+
677 * |VER | ULEN | UNAME | PLEN | PASSWD |
678 * +----+------+----------+------+----------+
679 * | 1 | 1 | 1 to 255 | 1 | 1 to 255 |
680 * +----+------+----------+------+----------+
681 */
682 len = 0;
683 socksreq[len++] = 1; /* username/pw subnegotiation version */
684 socksreq[len++] = (unsigned char) proxy_user_len;
685 if(proxy_user && proxy_user_len) {
686 /* the length must fit in a single byte */
687 if(proxy_user_len >= 255) {
688 failf(data, "Excessive user name length for proxy auth");
689 return CURLPX_LONG_USER;
690 }
691 memcpy(socksreq + len, proxy_user, proxy_user_len);
692 }
693 len += proxy_user_len;
694 socksreq[len++] = (unsigned char) proxy_password_len;
695 if(proxy_password && proxy_password_len) {
696 /* the length must fit in a single byte */
697 if(proxy_password_len > 255) {
698 failf(data, "Excessive password length for proxy auth");
699 return CURLPX_LONG_PASSWD;
700 }
701 memcpy(socksreq + len, proxy_password, proxy_password_len);
702 }
703 len += proxy_password_len;
704 sxstate(conn, CONNECT_AUTH_SEND);
705 sx->outstanding = len;
706 sx->outp = socksreq;
707 }
708 /* FALLTHROUGH */
709 case CONNECT_AUTH_SEND:
710 result = Curl_write_plain(conn, sockfd, (char *)sx->outp,
711 sx->outstanding, &written);
712 if(result && (CURLE_AGAIN != result)) {
713 failf(data, "Failed to send SOCKS5 sub-negotiation request.");
714 return CURLPX_SEND_AUTH;
715 }
716 if(sx->outstanding != written) {
717 /* remain in state */
718 sx->outstanding -= written;
719 sx->outp += written;
720 return CURLPX_OK;
721 }
722 sx->outp = socksreq;
723 sx->outstanding = 2;
724 sxstate(conn, CONNECT_AUTH_READ);
725 /* FALLTHROUGH */
726 case CONNECT_AUTH_READ:
727 result = Curl_read_plain(sockfd, (char *)sx->outp,
728 sx->outstanding, &actualread);
729 if(result && (CURLE_AGAIN != result)) {
730 failf(data, "Unable to receive SOCKS5 sub-negotiation response.");
731 return CURLPX_RECV_AUTH;
732 }
733 else if(!result && !actualread) {
734 /* connection closed */
735 failf(data, "connection to proxy closed");
736 return CURLPX_CLOSED;
737 }
738 else if(actualread != sx->outstanding) {
739 /* remain in state */
740 sx->outstanding -= actualread;
741 sx->outp += actualread;
742 return CURLPX_OK;
743 }
744 /* ignore the first (VER) byte */
745 else if(socksreq[1] != 0) { /* status */
746 failf(data, "User was rejected by the SOCKS5 server (%d %d).",
747 socksreq[0], socksreq[1]);
748 return CURLPX_USER_REJECTED;
749 }
750
751 /* Everything is good so far, user was authenticated! */
752 sxstate(conn, CONNECT_REQ_INIT);
753 /* FALLTHROUGH */
754 CONNECT_REQ_INIT:
755 case CONNECT_REQ_INIT:
756 if(socks5_resolve_local) {
757 enum resolve_t rc = Curl_resolv(conn, hostname, remote_port,
758 FALSE, &dns);
759
760 if(rc == CURLRESOLV_ERROR)
761 return CURLPX_RESOLVE_HOST;
762
763 if(rc == CURLRESOLV_PENDING) {
764 sxstate(conn, CONNECT_RESOLVING);
765 return CURLPX_OK;
766 }
767 sxstate(conn, CONNECT_RESOLVED);
768 goto CONNECT_RESOLVED;
769 }
770 goto CONNECT_RESOLVE_REMOTE;
771
772 case CONNECT_RESOLVING:
773 /* check if we have the name resolved by now */
774 dns = Curl_fetch_addr(conn, hostname, (int)conn->port);
775
776 if(dns) {
777 #ifdef CURLRES_ASYNCH
778 conn->async.dns = dns;
779 conn->async.done = TRUE;
780 #endif
781 infof(data, "SOCKS5: hostname '%s' found\n", hostname);
782 }
783
784 if(!dns) {
785 result = Curl_resolv_check(data->conn, &dns);
786 if(!dns) {
787 if(result)
788 return CURLPX_RESOLVE_HOST;
789 return CURLPX_OK;
790 }
791 }
792 /* FALLTHROUGH */
793 CONNECT_RESOLVED:
794 case CONNECT_RESOLVED: {
795 struct Curl_addrinfo *hp = NULL;
796 size_t destlen;
797 if(dns)
798 hp = dns->addr;
799 if(!hp) {
800 failf(data, "Failed to resolve \"%s\" for SOCKS5 connect.",
801 hostname);
802 return CURLPX_RESOLVE_HOST;
803 }
804
805 Curl_printable_address(hp, dest, sizeof(dest));
806 destlen = strlen(dest);
807 msnprintf(dest + destlen, sizeof(dest) - destlen, ":%d", remote_port);
808
809 len = 0;
810 socksreq[len++] = 5; /* version (SOCKS5) */
811 socksreq[len++] = 1; /* connect */
812 socksreq[len++] = 0; /* must be zero */
813 if(hp->ai_family == AF_INET) {
814 int i;
815 struct sockaddr_in *saddr_in;
816 socksreq[len++] = 1; /* ATYP: IPv4 = 1 */
817
818 saddr_in = (struct sockaddr_in *)(void *)hp->ai_addr;
819 for(i = 0; i < 4; i++) {
820 socksreq[len++] = ((unsigned char *)&saddr_in->sin_addr.s_addr)[i];
821 }
822
823 infof(data, "SOCKS5 connect to IPv4 %s (locally resolved)\n", dest);
824 }
825 #ifdef ENABLE_IPV6
826 else if(hp->ai_family == AF_INET6) {
827 int i;
828 struct sockaddr_in6 *saddr_in6;
829 socksreq[len++] = 4; /* ATYP: IPv6 = 4 */
830
831 saddr_in6 = (struct sockaddr_in6 *)(void *)hp->ai_addr;
832 for(i = 0; i < 16; i++) {
833 socksreq[len++] =
834 ((unsigned char *)&saddr_in6->sin6_addr.s6_addr)[i];
835 }
836
837 infof(data, "SOCKS5 connect to IPv6 %s (locally resolved)\n", dest);
838 }
839 #endif
840 else {
841 hp = NULL; /* fail! */
842 failf(data, "SOCKS5 connection to %s not supported\n", dest);
843 }
844
845 Curl_resolv_unlock(data, dns); /* not used anymore from now on */
846 goto CONNECT_REQ_SEND;
847 }
848 CONNECT_RESOLVE_REMOTE:
849 case CONNECT_RESOLVE_REMOTE:
850 /* Authentication is complete, now specify destination to the proxy */
851 len = 0;
852 socksreq[len++] = 5; /* version (SOCKS5) */
853 socksreq[len++] = 1; /* connect */
854 socksreq[len++] = 0; /* must be zero */
855
856 if(!socks5_resolve_local) {
857 socksreq[len++] = 3; /* ATYP: domain name = 3 */
858 socksreq[len++] = (char) hostname_len; /* one byte address length */
859 memcpy(&socksreq[len], hostname, hostname_len); /* address w/o NULL */
860 len += hostname_len;
861 infof(data, "SOCKS5 connect to %s:%d (remotely resolved)\n",
862 hostname, remote_port);
863 }
864 /* FALLTHROUGH */
865
866 CONNECT_REQ_SEND:
867 case CONNECT_REQ_SEND:
868 /* PORT MSB */
869 socksreq[len++] = (unsigned char)((remote_port >> 8) & 0xff);
870 /* PORT LSB */
871 socksreq[len++] = (unsigned char)(remote_port & 0xff);
872
873 #if defined(HAVE_GSSAPI) || defined(USE_WINDOWS_SSPI)
874 if(conn->socks5_gssapi_enctype) {
875 failf(data, "SOCKS5 GSS-API protection not yet implemented.");
876 return CURLPX_GSSAPI_PROTECTION;
877 }
878 #endif
879 sx->outp = socksreq;
880 sx->outstanding = len;
881 sxstate(conn, CONNECT_REQ_SENDING);
882 /* FALLTHROUGH */
883 case CONNECT_REQ_SENDING:
884 result = Curl_write_plain(conn, sockfd, (char *)sx->outp,
885 sx->outstanding, &written);
886 if(result && (CURLE_AGAIN != result)) {
887 failf(data, "Failed to send SOCKS5 connect request.");
888 return CURLPX_SEND_REQUEST;
889 }
890 if(sx->outstanding != written) {
891 /* remain in state */
892 sx->outstanding -= written;
893 sx->outp += written;
894 return CURLPX_OK;
895 }
896 #if defined(HAVE_GSSAPI) || defined(USE_WINDOWS_SSPI)
897 if(conn->socks5_gssapi_enctype) {
898 failf(data, "SOCKS5 GSS-API protection not yet implemented.");
899 return CURLPX_GSSAPI_PROTECTION;
900 }
901 #endif
902 sx->outstanding = 10; /* minimum packet size is 10 */
903 sx->outp = socksreq;
904 sxstate(conn, CONNECT_REQ_READ);
905 /* FALLTHROUGH */
906 case CONNECT_REQ_READ:
907 result = Curl_read_plain(sockfd, (char *)sx->outp,
908 sx->outstanding, &actualread);
909 if(result && (CURLE_AGAIN != result)) {
910 failf(data, "Failed to receive SOCKS5 connect request ack.");
911 return CURLPX_RECV_REQACK;
912 }
913 else if(!result && !actualread) {
914 /* connection closed */
915 failf(data, "connection to proxy closed");
916 return CURLPX_CLOSED;
917 }
918 else if(actualread != sx->outstanding) {
919 /* remain in state */
920 sx->outstanding -= actualread;
921 sx->outp += actualread;
922 return CURLPX_OK;
923 }
924
925 if(socksreq[0] != 5) { /* version */
926 failf(data,
927 "SOCKS5 reply has wrong version, version should be 5.");
928 return CURLPX_BAD_VERSION;
929 }
930 else if(socksreq[1] != 0) { /* Anything besides 0 is an error */
931 CURLproxycode rc = CURLPX_REPLY_UNASSIGNED;
932 int code = socksreq[1];
933 failf(data, "Can't complete SOCKS5 connection to %s. (%d)",
934 hostname, (unsigned char)socksreq[1]);
935 if(code < 9) {
936 /* RFC 1928 section 6 lists: */
937 static const CURLproxycode lookup[] = {
938 CURLPX_OK,
939 CURLPX_REPLY_GENERAL_SERVER_FAILURE,
940 CURLPX_REPLY_NOT_ALLOWED,
941 CURLPX_REPLY_NETWORK_UNREACHABLE,
942 CURLPX_REPLY_HOST_UNREACHABLE,
943 CURLPX_REPLY_CONNECTION_REFUSED,
944 CURLPX_REPLY_TTL_EXPIRED,
945 CURLPX_REPLY_COMMAND_NOT_SUPPORTED,
946 CURLPX_REPLY_ADDRESS_TYPE_NOT_SUPPORTED,
947 };
948 rc = lookup[code];
949 }
950 return rc;
951 }
952
953 /* Fix: in general, returned BND.ADDR is variable length parameter by RFC
954 1928, so the reply packet should be read until the end to avoid errors
955 at subsequent protocol level.
956
957 +----+-----+-------+------+----------+----------+
958 |VER | REP | RSV | ATYP | BND.ADDR | BND.PORT |
959 +----+-----+-------+------+----------+----------+
960 | 1 | 1 | X'00' | 1 | Variable | 2 |
961 +----+-----+-------+------+----------+----------+
962
963 ATYP:
964 o IP v4 address: X'01', BND.ADDR = 4 byte
965 o domain name: X'03', BND.ADDR = [ 1 byte length, string ]
966 o IP v6 address: X'04', BND.ADDR = 16 byte
967 */
968
969 /* Calculate real packet size */
970 if(socksreq[3] == 3) {
971 /* domain name */
972 int addrlen = (int) socksreq[4];
973 len = 5 + addrlen + 2;
974 }
975 else if(socksreq[3] == 4) {
976 /* IPv6 */
977 len = 4 + 16 + 2;
978 }
979 else if(socksreq[3] == 1) {
980 len = 4 + 4 + 2;
981 }
982 else {
983 failf(data, "SOCKS5 reply has wrong address type.");
984 return CURLPX_BAD_ADDRESS_TYPE;
985 }
986
987 /* At this point we already read first 10 bytes */
988 #if defined(HAVE_GSSAPI) || defined(USE_WINDOWS_SSPI)
989 if(!conn->socks5_gssapi_enctype) {
990 /* decrypt_gssapi_blockread already read the whole packet */
991 #endif
992 if(len > 10) {
993 sx->outstanding = len - 10; /* get the rest */
994 sx->outp = &socksreq[10];
995 sxstate(conn, CONNECT_REQ_READ_MORE);
996 }
997 else {
998 sxstate(conn, CONNECT_DONE);
999 break;
1000 }
1001 #if defined(HAVE_GSSAPI) || defined(USE_WINDOWS_SSPI)
1002 }
1003 #endif
1004 /* FALLTHROUGH */
1005 case CONNECT_REQ_READ_MORE:
1006 result = Curl_read_plain(sockfd, (char *)sx->outp,
1007 sx->outstanding, &actualread);
1008 if(result && (CURLE_AGAIN != result)) {
1009 failf(data, "Failed to receive SOCKS5 connect request ack.");
1010 return CURLPX_RECV_ADDRESS;
1011 }
1012 else if(!result && !actualread) {
1013 /* connection closed */
1014 failf(data, "connection to proxy closed");
1015 return CURLPX_CLOSED;
1016 }
1017 else if(actualread != sx->outstanding) {
1018 /* remain in state */
1019 sx->outstanding -= actualread;
1020 sx->outp += actualread;
1021 return CURLPX_OK;
1022 }
1023 sxstate(conn, CONNECT_DONE);
1024 }
1025 infof(data, "SOCKS5 request granted.\n");
1026
1027 *done = TRUE;
1028 return CURLPX_OK; /* Proxy was successful! */
1029 }
1030
1031 #endif /* CURL_DISABLE_PROXY */
1032