1 /***************************************************************************
2 * _ _ ____ _
3 * Project ___| | | | _ \| |
4 * / __| | | | |_) | |
5 * | (__| |_| | _ <| |___
6 * \___|\___/|_| \_\_____|
7 *
8 * Copyright (C) 1998 - 2019, 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
41 /* The last #include file should be: */
42 #include "memdebug.h"
43
44 /*
45 * Helper read-from-socket functions. Does the same as Curl_read() but it
46 * blocks until all bytes amount of buffersize will be read. No more, no less.
47 *
48 * This is STUPID BLOCKING behaviour which we frown upon, but right now this
49 * is what we have...
50 */
Curl_blockread_all(struct connectdata * conn,curl_socket_t sockfd,char * buf,ssize_t buffersize,ssize_t * n)51 int Curl_blockread_all(struct connectdata *conn, /* connection data */
52 curl_socket_t sockfd, /* read from this socket */
53 char *buf, /* store read data here */
54 ssize_t buffersize, /* max amount to read */
55 ssize_t *n) /* amount bytes read */
56 {
57 ssize_t nread = 0;
58 ssize_t allread = 0;
59 int result;
60 *n = 0;
61 for(;;) {
62 timediff_t timeleft = Curl_timeleft(conn->data, NULL, TRUE);
63 if(timeleft < 0) {
64 /* we already got the timeout */
65 result = CURLE_OPERATION_TIMEDOUT;
66 break;
67 }
68 if(SOCKET_READABLE(sockfd, timeleft) <= 0) {
69 result = ~CURLE_OK;
70 break;
71 }
72 result = Curl_read_plain(sockfd, buf, buffersize, &nread);
73 if(CURLE_AGAIN == result)
74 continue;
75 if(result)
76 break;
77
78 if(buffersize == nread) {
79 allread += nread;
80 *n = allread;
81 result = CURLE_OK;
82 break;
83 }
84 if(!nread) {
85 result = ~CURLE_OK;
86 break;
87 }
88
89 buffersize -= nread;
90 buf += nread;
91 allread += nread;
92 }
93 return result;
94 }
95
96 /*
97 * This function logs in to a SOCKS4 proxy and sends the specifics to the final
98 * destination server.
99 *
100 * Reference :
101 * https://www.openssh.com/txt/socks4.protocol
102 *
103 * Note :
104 * Set protocol4a=true for "SOCKS 4A (Simple Extension to SOCKS 4 Protocol)"
105 * Nonsupport "Identification Protocol (RFC1413)"
106 */
Curl_SOCKS4(const char * proxy_user,const char * hostname,int remote_port,int sockindex,struct connectdata * conn)107 CURLcode Curl_SOCKS4(const char *proxy_user,
108 const char *hostname,
109 int remote_port,
110 int sockindex,
111 struct connectdata *conn)
112 {
113 const bool protocol4a =
114 (conn->socks_proxy.proxytype == CURLPROXY_SOCKS4A) ? TRUE : FALSE;
115 #define SOCKS4REQLEN 262
116 unsigned char socksreq[SOCKS4REQLEN]; /* room for SOCKS4 request incl. user
117 id */
118 CURLcode code;
119 curl_socket_t sock = conn->sock[sockindex];
120 struct Curl_easy *data = conn->data;
121
122 if(Curl_timeleft(data, NULL, TRUE) < 0) {
123 /* time-out, bail out, go home */
124 failf(data, "Connection time-out");
125 return CURLE_OPERATION_TIMEDOUT;
126 }
127
128 if(conn->bits.httpproxy)
129 infof(conn->data, "SOCKS4%s: connecting to HTTP proxy %s port %d\n",
130 protocol4a ? "a" : "", hostname, remote_port);
131
132 (void)curlx_nonblock(sock, FALSE);
133
134 infof(data, "SOCKS4 communication to %s:%d\n", hostname, remote_port);
135
136 /*
137 * Compose socks4 request
138 *
139 * Request format
140 *
141 * +----+----+----+----+----+----+----+----+----+----+....+----+
142 * | VN | CD | DSTPORT | DSTIP | USERID |NULL|
143 * +----+----+----+----+----+----+----+----+----+----+....+----+
144 * # of bytes: 1 1 2 4 variable 1
145 */
146
147 socksreq[0] = 4; /* version (SOCKS4) */
148 socksreq[1] = 1; /* connect */
149 socksreq[2] = (unsigned char)((remote_port >> 8) & 0xff); /* PORT MSB */
150 socksreq[3] = (unsigned char)(remote_port & 0xff); /* PORT LSB */
151
152 /* DNS resolve only for SOCKS4, not SOCKS4a */
153 if(!protocol4a) {
154 struct Curl_dns_entry *dns;
155 Curl_addrinfo *hp = NULL;
156 int rc;
157
158 rc = Curl_resolv(conn, hostname, remote_port, &dns);
159
160 if(rc == CURLRESOLV_ERROR)
161 return CURLE_COULDNT_RESOLVE_PROXY;
162
163 if(rc == CURLRESOLV_PENDING)
164 /* ignores the return code, but 'dns' remains NULL on failure */
165 (void)Curl_resolver_wait_resolv(conn, &dns);
166
167 /*
168 * We cannot use 'hostent' as a struct that Curl_resolv() returns. It
169 * returns a Curl_addrinfo pointer that may not always look the same.
170 */
171 if(dns)
172 hp = dns->addr;
173 if(hp) {
174 char buf[64];
175 Curl_printable_address(hp, buf, sizeof(buf));
176
177 if(hp->ai_family == AF_INET) {
178 struct sockaddr_in *saddr_in;
179
180 saddr_in = (struct sockaddr_in *)(void *)hp->ai_addr;
181 socksreq[4] = ((unsigned char *)&saddr_in->sin_addr.s_addr)[0];
182 socksreq[5] = ((unsigned char *)&saddr_in->sin_addr.s_addr)[1];
183 socksreq[6] = ((unsigned char *)&saddr_in->sin_addr.s_addr)[2];
184 socksreq[7] = ((unsigned char *)&saddr_in->sin_addr.s_addr)[3];
185
186 infof(data, "SOCKS4 connect to IPv4 %s (locally resolved)\n", buf);
187 }
188 else {
189 hp = NULL; /* fail! */
190
191 failf(data, "SOCKS4 connection to %s not supported\n", buf);
192 }
193
194 Curl_resolv_unlock(data, dns); /* not used anymore from now on */
195 }
196 if(!hp) {
197 failf(data, "Failed to resolve \"%s\" for SOCKS4 connect.",
198 hostname);
199 return CURLE_COULDNT_RESOLVE_HOST;
200 }
201 }
202
203 /*
204 * This is currently not supporting "Identification Protocol (RFC1413)".
205 */
206 socksreq[8] = 0; /* ensure empty userid is NUL-terminated */
207 if(proxy_user) {
208 size_t plen = strlen(proxy_user);
209 if(plen >= sizeof(socksreq) - 8) {
210 failf(data, "Too long SOCKS proxy name, can't use!\n");
211 return CURLE_COULDNT_CONNECT;
212 }
213 /* copy the proxy name WITH trailing zero */
214 memcpy(socksreq + 8, proxy_user, plen + 1);
215 }
216
217 /*
218 * Make connection
219 */
220 {
221 int result;
222 ssize_t actualread;
223 ssize_t written;
224 ssize_t hostnamelen = 0;
225 ssize_t packetsize = 9 +
226 strlen((char *)socksreq + 8); /* size including NUL */
227
228 /* If SOCKS4a, set special invalid IP address 0.0.0.x */
229 if(protocol4a) {
230 socksreq[4] = 0;
231 socksreq[5] = 0;
232 socksreq[6] = 0;
233 socksreq[7] = 1;
234 /* If still enough room in buffer, also append hostname */
235 hostnamelen = (ssize_t)strlen(hostname) + 1; /* length including NUL */
236 if(packetsize + hostnamelen <= SOCKS4REQLEN)
237 strcpy((char *)socksreq + packetsize, hostname);
238 else
239 hostnamelen = 0; /* Flag: hostname did not fit in buffer */
240 }
241
242 /* Send request */
243 code = Curl_write_plain(conn, sock, (char *)socksreq,
244 packetsize + hostnamelen,
245 &written);
246 if(code || (written != packetsize + hostnamelen)) {
247 failf(data, "Failed to send SOCKS4 connect request.");
248 return CURLE_COULDNT_CONNECT;
249 }
250 if(protocol4a && hostnamelen == 0) {
251 /* SOCKS4a with very long hostname - send that name separately */
252 hostnamelen = (ssize_t)strlen(hostname) + 1;
253 code = Curl_write_plain(conn, sock, (char *)hostname, hostnamelen,
254 &written);
255 if(code || (written != hostnamelen)) {
256 failf(data, "Failed to send SOCKS4 connect request.");
257 return CURLE_COULDNT_CONNECT;
258 }
259 }
260
261 packetsize = 8; /* receive data size */
262
263 /* Receive response */
264 result = Curl_blockread_all(conn, sock, (char *)socksreq, packetsize,
265 &actualread);
266 if(result || (actualread != packetsize)) {
267 failf(data, "Failed to receive SOCKS4 connect request ack.");
268 return CURLE_COULDNT_CONNECT;
269 }
270
271 /*
272 * Response format
273 *
274 * +----+----+----+----+----+----+----+----+
275 * | VN | CD | DSTPORT | DSTIP |
276 * +----+----+----+----+----+----+----+----+
277 * # of bytes: 1 1 2 4
278 *
279 * VN is the version of the reply code and should be 0. CD is the result
280 * code with one of the following values:
281 *
282 * 90: request granted
283 * 91: request rejected or failed
284 * 92: request rejected because SOCKS server cannot connect to
285 * identd on the client
286 * 93: request rejected because the client program and identd
287 * report different user-ids
288 */
289
290 /* wrong version ? */
291 if(socksreq[0] != 0) {
292 failf(data,
293 "SOCKS4 reply has wrong version, version should be 4.");
294 return CURLE_COULDNT_CONNECT;
295 }
296
297 /* Result */
298 switch(socksreq[1]) {
299 case 90:
300 infof(data, "SOCKS4%s request granted.\n", protocol4a?"a":"");
301 break;
302 case 91:
303 failf(data,
304 "Can't complete SOCKS4 connection to %d.%d.%d.%d:%d. (%d)"
305 ", request rejected or failed.",
306 (unsigned char)socksreq[4], (unsigned char)socksreq[5],
307 (unsigned char)socksreq[6], (unsigned char)socksreq[7],
308 (((unsigned char)socksreq[2] << 8) | (unsigned char)socksreq[3]),
309 (unsigned char)socksreq[1]);
310 return CURLE_COULDNT_CONNECT;
311 case 92:
312 failf(data,
313 "Can't complete SOCKS4 connection to %d.%d.%d.%d:%d. (%d)"
314 ", request rejected because SOCKS server cannot connect to "
315 "identd on the client.",
316 (unsigned char)socksreq[4], (unsigned char)socksreq[5],
317 (unsigned char)socksreq[6], (unsigned char)socksreq[7],
318 (((unsigned char)socksreq[2] << 8) | (unsigned char)socksreq[3]),
319 (unsigned char)socksreq[1]);
320 return CURLE_COULDNT_CONNECT;
321 case 93:
322 failf(data,
323 "Can't complete SOCKS4 connection to %d.%d.%d.%d:%d. (%d)"
324 ", request rejected because the client program and identd "
325 "report different user-ids.",
326 (unsigned char)socksreq[4], (unsigned char)socksreq[5],
327 (unsigned char)socksreq[6], (unsigned char)socksreq[7],
328 (((unsigned char)socksreq[2] << 8) | (unsigned char)socksreq[3]),
329 (unsigned char)socksreq[1]);
330 return CURLE_COULDNT_CONNECT;
331 default:
332 failf(data,
333 "Can't complete SOCKS4 connection to %d.%d.%d.%d:%d. (%d)"
334 ", Unknown.",
335 (unsigned char)socksreq[4], (unsigned char)socksreq[5],
336 (unsigned char)socksreq[6], (unsigned char)socksreq[7],
337 (((unsigned char)socksreq[2] << 8) | (unsigned char)socksreq[3]),
338 (unsigned char)socksreq[1]);
339 return CURLE_COULDNT_CONNECT;
340 }
341 }
342
343 (void)curlx_nonblock(sock, TRUE);
344
345 return CURLE_OK; /* Proxy was successful! */
346 }
347
348 /*
349 * This function logs in to a SOCKS5 proxy and sends the specifics to the final
350 * destination server.
351 */
Curl_SOCKS5(const char * proxy_user,const char * proxy_password,const char * hostname,int remote_port,int sockindex,struct connectdata * conn)352 CURLcode Curl_SOCKS5(const char *proxy_user,
353 const char *proxy_password,
354 const char *hostname,
355 int remote_port,
356 int sockindex,
357 struct connectdata *conn)
358 {
359 /*
360 According to the RFC1928, section "6. Replies". This is what a SOCK5
361 replies:
362
363 +----+-----+-------+------+----------+----------+
364 |VER | REP | RSV | ATYP | BND.ADDR | BND.PORT |
365 +----+-----+-------+------+----------+----------+
366 | 1 | 1 | X'00' | 1 | Variable | 2 |
367 +----+-----+-------+------+----------+----------+
368
369 Where:
370
371 o VER protocol version: X'05'
372 o REP Reply field:
373 o X'00' succeeded
374 */
375
376 unsigned char socksreq[600]; /* room for large user/pw (255 max each) */
377 int idx;
378 ssize_t actualread;
379 ssize_t written;
380 int result;
381 CURLcode code;
382 curl_socket_t sock = conn->sock[sockindex];
383 struct Curl_easy *data = conn->data;
384 timediff_t timeout;
385 bool socks5_resolve_local =
386 (conn->socks_proxy.proxytype == CURLPROXY_SOCKS5) ? TRUE : FALSE;
387 const size_t hostname_len = strlen(hostname);
388 ssize_t len = 0;
389 const unsigned long auth = data->set.socks5auth;
390 bool allow_gssapi = FALSE;
391
392 if(conn->bits.httpproxy)
393 infof(conn->data, "SOCKS5: connecting to HTTP proxy %s port %d\n",
394 hostname, remote_port);
395
396 /* RFC1928 chapter 5 specifies max 255 chars for domain name in packet */
397 if(!socks5_resolve_local && hostname_len > 255) {
398 infof(conn->data, "SOCKS5: server resolving disabled for hostnames of "
399 "length > 255 [actual len=%zu]\n", hostname_len);
400 socks5_resolve_local = TRUE;
401 }
402
403 /* get timeout */
404 timeout = Curl_timeleft(data, NULL, TRUE);
405
406 if(timeout < 0) {
407 /* time-out, bail out, go home */
408 failf(data, "Connection time-out");
409 return CURLE_OPERATION_TIMEDOUT;
410 }
411
412 (void)curlx_nonblock(sock, TRUE);
413
414 /* wait until socket gets connected */
415 result = SOCKET_WRITABLE(sock, timeout);
416
417 if(-1 == result) {
418 failf(conn->data, "SOCKS5: no connection here");
419 return CURLE_COULDNT_CONNECT;
420 }
421 if(0 == result) {
422 failf(conn->data, "SOCKS5: connection timeout");
423 return CURLE_OPERATION_TIMEDOUT;
424 }
425
426 if(result & CURL_CSELECT_ERR) {
427 failf(conn->data, "SOCKS5: error occurred during connection");
428 return CURLE_COULDNT_CONNECT;
429 }
430
431 if(auth & ~(CURLAUTH_BASIC | CURLAUTH_GSSAPI))
432 infof(conn->data,
433 "warning: unsupported value passed to CURLOPT_SOCKS5_AUTH: %lu\n",
434 auth);
435 if(!(auth & CURLAUTH_BASIC))
436 /* disable username/password auth */
437 proxy_user = NULL;
438 #if defined(HAVE_GSSAPI) || defined(USE_WINDOWS_SSPI)
439 if(auth & CURLAUTH_GSSAPI)
440 allow_gssapi = TRUE;
441 #endif
442
443 idx = 0;
444 socksreq[idx++] = 5; /* version */
445 idx++; /* reserve for the number of authentication methods */
446 socksreq[idx++] = 0; /* no authentication */
447 if(allow_gssapi)
448 socksreq[idx++] = 1; /* GSS-API */
449 if(proxy_user)
450 socksreq[idx++] = 2; /* username/password */
451 /* write the number of authentication methods */
452 socksreq[1] = (unsigned char) (idx - 2);
453
454 (void)curlx_nonblock(sock, FALSE);
455
456 infof(data, "SOCKS5 communication to %s:%d\n", hostname, remote_port);
457
458 code = Curl_write_plain(conn, sock, (char *)socksreq, (2 + (int)socksreq[1]),
459 &written);
460 if(code || (written != (2 + (int)socksreq[1]))) {
461 failf(data, "Unable to send initial SOCKS5 request.");
462 return CURLE_COULDNT_CONNECT;
463 }
464
465 (void)curlx_nonblock(sock, TRUE);
466
467 result = SOCKET_READABLE(sock, timeout);
468
469 if(-1 == result) {
470 failf(conn->data, "SOCKS5 nothing to read");
471 return CURLE_COULDNT_CONNECT;
472 }
473 if(0 == result) {
474 failf(conn->data, "SOCKS5 read timeout");
475 return CURLE_OPERATION_TIMEDOUT;
476 }
477
478 if(result & CURL_CSELECT_ERR) {
479 failf(conn->data, "SOCKS5 read error occurred");
480 return CURLE_RECV_ERROR;
481 }
482
483 (void)curlx_nonblock(sock, FALSE);
484
485 result = Curl_blockread_all(conn, sock, (char *)socksreq, 2, &actualread);
486 if(result || (actualread != 2)) {
487 failf(data, "Unable to receive initial SOCKS5 response.");
488 return CURLE_COULDNT_CONNECT;
489 }
490
491 if(socksreq[0] != 5) {
492 failf(data, "Received invalid version in initial SOCKS5 response.");
493 return CURLE_COULDNT_CONNECT;
494 }
495 if(socksreq[1] == 0) {
496 /* Nothing to do, no authentication needed */
497 ;
498 }
499 #if defined(HAVE_GSSAPI) || defined(USE_WINDOWS_SSPI)
500 else if(allow_gssapi && (socksreq[1] == 1)) {
501 code = Curl_SOCKS5_gssapi_negotiate(sockindex, conn);
502 if(code) {
503 failf(data, "Unable to negotiate SOCKS5 GSS-API context.");
504 return CURLE_COULDNT_CONNECT;
505 }
506 }
507 #endif
508 else if(socksreq[1] == 2) {
509 /* Needs user name and password */
510 size_t proxy_user_len, proxy_password_len;
511 if(proxy_user && proxy_password) {
512 proxy_user_len = strlen(proxy_user);
513 proxy_password_len = strlen(proxy_password);
514 }
515 else {
516 proxy_user_len = 0;
517 proxy_password_len = 0;
518 }
519
520 /* username/password request looks like
521 * +----+------+----------+------+----------+
522 * |VER | ULEN | UNAME | PLEN | PASSWD |
523 * +----+------+----------+------+----------+
524 * | 1 | 1 | 1 to 255 | 1 | 1 to 255 |
525 * +----+------+----------+------+----------+
526 */
527 len = 0;
528 socksreq[len++] = 1; /* username/pw subnegotiation version */
529 socksreq[len++] = (unsigned char) proxy_user_len;
530 if(proxy_user && proxy_user_len)
531 memcpy(socksreq + len, proxy_user, proxy_user_len);
532 len += proxy_user_len;
533 socksreq[len++] = (unsigned char) proxy_password_len;
534 if(proxy_password && proxy_password_len)
535 memcpy(socksreq + len, proxy_password, proxy_password_len);
536 len += proxy_password_len;
537
538 code = Curl_write_plain(conn, sock, (char *)socksreq, len, &written);
539 if(code || (len != written)) {
540 failf(data, "Failed to send SOCKS5 sub-negotiation request.");
541 return CURLE_COULDNT_CONNECT;
542 }
543
544 result = Curl_blockread_all(conn, sock, (char *)socksreq, 2, &actualread);
545 if(result || (actualread != 2)) {
546 failf(data, "Unable to receive SOCKS5 sub-negotiation response.");
547 return CURLE_COULDNT_CONNECT;
548 }
549
550 /* ignore the first (VER) byte */
551 if(socksreq[1] != 0) { /* status */
552 failf(data, "User was rejected by the SOCKS5 server (%d %d).",
553 socksreq[0], socksreq[1]);
554 return CURLE_COULDNT_CONNECT;
555 }
556
557 /* Everything is good so far, user was authenticated! */
558 }
559 else {
560 /* error */
561 if(!allow_gssapi && (socksreq[1] == 1)) {
562 failf(data,
563 "SOCKS5 GSSAPI per-message authentication is not supported.");
564 return CURLE_COULDNT_CONNECT;
565 }
566 if(socksreq[1] == 255) {
567 if(!proxy_user || !*proxy_user) {
568 failf(data,
569 "No authentication method was acceptable. (It is quite likely"
570 " that the SOCKS5 server wanted a username/password, since none"
571 " was supplied to the server on this connection.)");
572 }
573 else {
574 failf(data, "No authentication method was acceptable.");
575 }
576 return CURLE_COULDNT_CONNECT;
577 }
578 else {
579 failf(data,
580 "Undocumented SOCKS5 mode attempted to be used by server.");
581 return CURLE_COULDNT_CONNECT;
582 }
583 }
584
585 /* Authentication is complete, now specify destination to the proxy */
586 len = 0;
587 socksreq[len++] = 5; /* version (SOCKS5) */
588 socksreq[len++] = 1; /* connect */
589 socksreq[len++] = 0; /* must be zero */
590
591 if(!socks5_resolve_local) {
592 socksreq[len++] = 3; /* ATYP: domain name = 3 */
593 socksreq[len++] = (char) hostname_len; /* address length */
594 memcpy(&socksreq[len], hostname, hostname_len); /* address str w/o NULL */
595 len += hostname_len;
596 }
597 else {
598 struct Curl_dns_entry *dns;
599 Curl_addrinfo *hp = NULL;
600 int rc = Curl_resolv(conn, hostname, remote_port, &dns);
601
602 if(rc == CURLRESOLV_ERROR)
603 return CURLE_COULDNT_RESOLVE_HOST;
604
605 if(rc == CURLRESOLV_PENDING) {
606 /* this requires that we're in "wait for resolve" state */
607 code = Curl_resolver_wait_resolv(conn, &dns);
608 if(code)
609 return code;
610 }
611
612 /*
613 * We cannot use 'hostent' as a struct that Curl_resolv() returns. It
614 * returns a Curl_addrinfo pointer that may not always look the same.
615 */
616 if(dns)
617 hp = dns->addr;
618 if(hp) {
619 char buf[64];
620 Curl_printable_address(hp, buf, sizeof(buf));
621
622 if(hp->ai_family == AF_INET) {
623 int i;
624 struct sockaddr_in *saddr_in;
625 socksreq[len++] = 1; /* ATYP: IPv4 = 1 */
626
627 saddr_in = (struct sockaddr_in *)(void *)hp->ai_addr;
628 for(i = 0; i < 4; i++) {
629 socksreq[len++] = ((unsigned char *)&saddr_in->sin_addr.s_addr)[i];
630 }
631
632 infof(data, "SOCKS5 connect to IPv4 %s (locally resolved)\n", buf);
633 }
634 #ifdef ENABLE_IPV6
635 else if(hp->ai_family == AF_INET6) {
636 int i;
637 struct sockaddr_in6 *saddr_in6;
638 socksreq[len++] = 4; /* ATYP: IPv6 = 4 */
639
640 saddr_in6 = (struct sockaddr_in6 *)(void *)hp->ai_addr;
641 for(i = 0; i < 16; i++) {
642 socksreq[len++] =
643 ((unsigned char *)&saddr_in6->sin6_addr.s6_addr)[i];
644 }
645
646 infof(data, "SOCKS5 connect to IPv6 %s (locally resolved)\n", buf);
647 }
648 #endif
649 else {
650 hp = NULL; /* fail! */
651
652 failf(data, "SOCKS5 connection to %s not supported\n", buf);
653 }
654
655 Curl_resolv_unlock(data, dns); /* not used anymore from now on */
656 }
657 if(!hp) {
658 failf(data, "Failed to resolve \"%s\" for SOCKS5 connect.",
659 hostname);
660 return CURLE_COULDNT_RESOLVE_HOST;
661 }
662 }
663
664 socksreq[len++] = (unsigned char)((remote_port >> 8) & 0xff); /* PORT MSB */
665 socksreq[len++] = (unsigned char)(remote_port & 0xff); /* PORT LSB */
666
667 #if defined(HAVE_GSSAPI) || defined(USE_WINDOWS_SSPI)
668 if(conn->socks5_gssapi_enctype) {
669 failf(data, "SOCKS5 GSS-API protection not yet implemented.");
670 }
671 else
672 #endif
673 code = Curl_write_plain(conn, sock, (char *)socksreq, len, &written);
674
675 if(code || (len != written)) {
676 failf(data, "Failed to send SOCKS5 connect request.");
677 return CURLE_COULDNT_CONNECT;
678 }
679
680 len = 10; /* minimum packet size is 10 */
681
682 #if defined(HAVE_GSSAPI) || defined(USE_WINDOWS_SSPI)
683 if(conn->socks5_gssapi_enctype) {
684 failf(data, "SOCKS5 GSS-API protection not yet implemented.");
685 }
686 else
687 #endif
688 result = Curl_blockread_all(conn, sock, (char *)socksreq,
689 len, &actualread);
690
691 if(result || (len != actualread)) {
692 failf(data, "Failed to receive SOCKS5 connect request ack.");
693 return CURLE_COULDNT_CONNECT;
694 }
695
696 if(socksreq[0] != 5) { /* version */
697 failf(data,
698 "SOCKS5 reply has wrong version, version should be 5.");
699 return CURLE_COULDNT_CONNECT;
700 }
701
702 /* Fix: in general, returned BND.ADDR is variable length parameter by RFC
703 1928, so the reply packet should be read until the end to avoid errors at
704 subsequent protocol level.
705
706 +----+-----+-------+------+----------+----------+
707 |VER | REP | RSV | ATYP | BND.ADDR | BND.PORT |
708 +----+-----+-------+------+----------+----------+
709 | 1 | 1 | X'00' | 1 | Variable | 2 |
710 +----+-----+-------+------+----------+----------+
711
712 ATYP:
713 o IP v4 address: X'01', BND.ADDR = 4 byte
714 o domain name: X'03', BND.ADDR = [ 1 byte length, string ]
715 o IP v6 address: X'04', BND.ADDR = 16 byte
716 */
717
718 /* Calculate real packet size */
719 if(socksreq[3] == 3) {
720 /* domain name */
721 int addrlen = (int) socksreq[4];
722 len = 5 + addrlen + 2;
723 }
724 else if(socksreq[3] == 4) {
725 /* IPv6 */
726 len = 4 + 16 + 2;
727 }
728
729 /* At this point we already read first 10 bytes */
730 #if defined(HAVE_GSSAPI) || defined(USE_WINDOWS_SSPI)
731 if(!conn->socks5_gssapi_enctype) {
732 /* decrypt_gssapi_blockread already read the whole packet */
733 #endif
734 if(len > 10) {
735 result = Curl_blockread_all(conn, sock, (char *)&socksreq[10],
736 len - 10, &actualread);
737 if(result || ((len - 10) != actualread)) {
738 failf(data, "Failed to receive SOCKS5 connect request ack.");
739 return CURLE_COULDNT_CONNECT;
740 }
741 }
742 #if defined(HAVE_GSSAPI) || defined(USE_WINDOWS_SSPI)
743 }
744 #endif
745
746 if(socksreq[1] != 0) { /* Anything besides 0 is an error */
747 if(socksreq[3] == 1) {
748 failf(data,
749 "Can't complete SOCKS5 connection to %d.%d.%d.%d:%d. (%d)",
750 (unsigned char)socksreq[4], (unsigned char)socksreq[5],
751 (unsigned char)socksreq[6], (unsigned char)socksreq[7],
752 (((unsigned char)socksreq[8] << 8) |
753 (unsigned char)socksreq[9]),
754 (unsigned char)socksreq[1]);
755 }
756 else if(socksreq[3] == 3) {
757 unsigned char port_upper = (unsigned char)socksreq[len - 2];
758 socksreq[len - 2] = 0;
759 failf(data,
760 "Can't complete SOCKS5 connection to %s:%d. (%d)",
761 (char *)&socksreq[5],
762 ((port_upper << 8) |
763 (unsigned char)socksreq[len - 1]),
764 (unsigned char)socksreq[1]);
765 socksreq[len - 2] = port_upper;
766 }
767 else if(socksreq[3] == 4) {
768 failf(data,
769 "Can't complete SOCKS5 connection to %02x%02x:%02x%02x:"
770 "%02x%02x:%02x%02x:%02x%02x:%02x%02x:%02x%02x:%02x%02x:%d. (%d)",
771 (unsigned char)socksreq[4], (unsigned char)socksreq[5],
772 (unsigned char)socksreq[6], (unsigned char)socksreq[7],
773 (unsigned char)socksreq[8], (unsigned char)socksreq[9],
774 (unsigned char)socksreq[10], (unsigned char)socksreq[11],
775 (unsigned char)socksreq[12], (unsigned char)socksreq[13],
776 (unsigned char)socksreq[14], (unsigned char)socksreq[15],
777 (unsigned char)socksreq[16], (unsigned char)socksreq[17],
778 (unsigned char)socksreq[18], (unsigned char)socksreq[19],
779 (((unsigned char)socksreq[20] << 8) |
780 (unsigned char)socksreq[21]),
781 (unsigned char)socksreq[1]);
782 }
783 return CURLE_COULDNT_CONNECT;
784 }
785 infof(data, "SOCKS5 request granted.\n");
786
787 (void)curlx_nonblock(sock, TRUE);
788 return CURLE_OK; /* Proxy was successful! */
789 }
790
791 #endif /* CURL_DISABLE_PROXY */
792