xref: /freebsd/lib/libfetch/common.c (revision 32cd3ee5901ea33d41ff550e5f40ce743c8d4165)
1 /*-
2  * SPDX-License-Identifier: BSD-3-Clause
3  *
4  * Copyright (c) 1998-2016 Dag-Erling Smørgrav
5  * Copyright (c) 2013 Michael Gmelin <freebsd@grem.de>
6  * All rights reserved.
7  *
8  * Redistribution and use in source and binary forms, with or without
9  * modification, are permitted provided that the following conditions
10  * are met:
11  * 1. Redistributions of source code must retain the above copyright
12  *    notice, this list of conditions and the following disclaimer
13  *    in this position and unchanged.
14  * 2. Redistributions in binary form must reproduce the above copyright
15  *    notice, this list of conditions and the following disclaimer in the
16  *    documentation and/or other materials provided with the distribution.
17  * 3. The name of the author may not be used to endorse or promote products
18  *    derived from this software without specific prior written permission
19  *
20  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
21  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
22  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
23  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
24  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
25  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
26  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
27  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
28  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
29  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
30  */
31 
32 #include <sys/param.h>
33 #include <sys/socket.h>
34 #include <sys/time.h>
35 #include <sys/uio.h>
36 
37 #include <netinet/in.h>
38 
39 #include <ctype.h>
40 #include <errno.h>
41 #include <fcntl.h>
42 #include <inttypes.h>
43 #include <netdb.h>
44 #include <paths.h>
45 #include <poll.h>
46 #include <pwd.h>
47 #include <stdarg.h>
48 #include <stdlib.h>
49 #include <stdio.h>
50 #include <string.h>
51 #include <unistd.h>
52 
53 #ifdef WITH_SSL
54 #include <openssl/x509v3.h>
55 #endif
56 
57 #include "fetch.h"
58 #include "common.h"
59 
60 
61 /*** Local data **************************************************************/
62 
63 /*
64  * Error messages for resolver errors
65  */
66 static struct fetcherr netdb_errlist[] = {
67 #ifdef EAI_ADDRFAMILY
68 	{ EAI_ADDRFAMILY, FETCH_RESOLV, "Address family for host not supported" },
69 #endif
70 #ifdef EAI_NODATA
71 	{ EAI_NODATA,	FETCH_RESOLV,	"No address for host" },
72 #endif
73 	{ EAI_AGAIN,	FETCH_TEMP,	"Transient resolver failure" },
74 	{ EAI_FAIL,	FETCH_RESOLV,	"Non-recoverable resolver failure" },
75 	{ EAI_NONAME,	FETCH_RESOLV,	"Host does not resolve" },
76 	{ -1,		FETCH_UNKNOWN,	"Unknown resolver error" }
77 };
78 
79 /*
80  * SOCKS5 error enumerations
81  */
82 enum SOCKS5_ERR {
83 /* Protocol errors */
84 	SOCKS5_ERR_SELECTION,
85 	SOCKS5_ERR_READ_METHOD,
86 	SOCKS5_ERR_VER5_ONLY,
87 	SOCKS5_ERR_NOMETHODS,
88 	SOCKS5_ERR_NOTIMPLEMENTED,
89 	SOCKS5_ERR_HOSTNAME_SIZE,
90 	SOCKS5_ERR_REQUEST,
91 	SOCKS5_ERR_REPLY,
92 	SOCKS5_ERR_NON_VER5_RESP,
93 	SOCKS5_ERR_GENERAL,
94 	SOCKS5_ERR_NOT_ALLOWED,
95 	SOCKS5_ERR_NET_UNREACHABLE,
96 	SOCKS5_ERR_HOST_UNREACHABLE,
97 	SOCKS5_ERR_CONN_REFUSED,
98 	SOCKS5_ERR_TTL_EXPIRED,
99 	SOCKS5_ERR_COM_UNSUPPORTED,
100 	SOCKS5_ERR_ADDR_UNSUPPORTED,
101 	SOCKS5_ERR_UNSPECIFIED,
102 /* Configuration errors */
103 	SOCKS5_ERR_BAD_HOST,
104 	SOCKS5_ERR_BAD_PROXY_FORMAT,
105 	SOCKS5_ERR_BAD_PORT
106 };
107 
108 /*
109  * Error messages for SOCKS5 errors
110  */
111 static struct fetcherr socks5_errlist[] = {
112 /* SOCKS5 protocol errors */
113 	{ SOCKS5_ERR_SELECTION,		FETCH_ABORT,	"SOCKS5: Failed to send selection method" },
114 	{ SOCKS5_ERR_READ_METHOD,	FETCH_ABORT,	"SOCKS5: Failed to read method" },
115 	{ SOCKS5_ERR_VER5_ONLY,		FETCH_PROTO,	"SOCKS5: Only version 5 is implemented" },
116 	{ SOCKS5_ERR_NOMETHODS,		FETCH_PROTO,	"SOCKS5: No acceptable methods" },
117 	{ SOCKS5_ERR_NOTIMPLEMENTED,	FETCH_PROTO,	"SOCKS5: Method currently not implemented" },
118 	{ SOCKS5_ERR_HOSTNAME_SIZE,	FETCH_PROTO,	"SOCKS5: Hostname size is above 256 bytes" },
119 	{ SOCKS5_ERR_REQUEST,		FETCH_PROTO,	"SOCKS5: Failed to request" },
120 	{ SOCKS5_ERR_REPLY,		FETCH_PROTO,	"SOCKS5: Failed to receive reply" },
121 	{ SOCKS5_ERR_NON_VER5_RESP,	FETCH_PROTO,	"SOCKS5: Server responded with a non-version 5 response" },
122 	{ SOCKS5_ERR_GENERAL,		FETCH_ABORT,	"SOCKS5: General server failure" },
123 	{ SOCKS5_ERR_NOT_ALLOWED,	FETCH_AUTH,	"SOCKS5: Connection not allowed by ruleset" },
124 	{ SOCKS5_ERR_NET_UNREACHABLE,	FETCH_NETWORK,	"SOCKS5: Network unreachable" },
125 	{ SOCKS5_ERR_HOST_UNREACHABLE,	FETCH_ABORT,	"SOCKS5: Host unreachable" },
126 	{ SOCKS5_ERR_CONN_REFUSED,	FETCH_ABORT,	"SOCKS5: Connection refused" },
127 	{ SOCKS5_ERR_TTL_EXPIRED,	FETCH_TIMEOUT,	"SOCKS5: TTL expired" },
128 	{ SOCKS5_ERR_COM_UNSUPPORTED,	FETCH_PROTO,	"SOCKS5: Command not supported" },
129 	{ SOCKS5_ERR_ADDR_UNSUPPORTED,	FETCH_ABORT,	"SOCKS5: Address type not supported" },
130 	{ SOCKS5_ERR_UNSPECIFIED,	FETCH_UNKNOWN,	"SOCKS5: Unspecified error" },
131 /* Configuration error */
132 	{ SOCKS5_ERR_BAD_HOST,		FETCH_ABORT,	"SOCKS5: Bad proxy host" },
133 	{ SOCKS5_ERR_BAD_PROXY_FORMAT,	FETCH_ABORT,	"SOCKS5: Bad proxy format" },
134 	{ SOCKS5_ERR_BAD_PORT,		FETCH_ABORT,	"SOCKS5: Bad port" }
135 };
136 
137 /* End-of-Line */
138 static const char ENDL[2] = { '\r', '\n' };
139 
140 
141 /*** Error-reporting functions ***********************************************/
142 
143 /*
144  * Map error code to string
145  */
146 static struct fetcherr *
147 fetch_finderr(struct fetcherr *p, int e)
148 {
149 	while (p->num != -1 && p->num != e)
150 		p++;
151 	return (p);
152 }
153 
154 /*
155  * Set error code
156  */
157 void
158 fetch_seterr(struct fetcherr *p, int e)
159 {
160 	p = fetch_finderr(p, e);
161 	fetchLastErrCode = p->cat;
162 	snprintf(fetchLastErrString, MAXERRSTRING, "%s", p->string);
163 }
164 
165 /*
166  * Set error code according to errno
167  */
168 void
169 fetch_syserr(void)
170 {
171 	switch (errno) {
172 	case 0:
173 		fetchLastErrCode = FETCH_OK;
174 		break;
175 	case EPERM:
176 	case EACCES:
177 	case EROFS:
178 	case EAUTH:
179 	case ENEEDAUTH:
180 		fetchLastErrCode = FETCH_AUTH;
181 		break;
182 	case ENOENT:
183 	case EISDIR: /* XXX */
184 		fetchLastErrCode = FETCH_UNAVAIL;
185 		break;
186 	case ENOMEM:
187 		fetchLastErrCode = FETCH_MEMORY;
188 		break;
189 	case EBUSY:
190 	case EAGAIN:
191 		fetchLastErrCode = FETCH_TEMP;
192 		break;
193 	case EEXIST:
194 		fetchLastErrCode = FETCH_EXISTS;
195 		break;
196 	case ENOSPC:
197 		fetchLastErrCode = FETCH_FULL;
198 		break;
199 	case EADDRINUSE:
200 	case EADDRNOTAVAIL:
201 	case ENETDOWN:
202 	case ENETUNREACH:
203 	case ENETRESET:
204 	case EHOSTUNREACH:
205 		fetchLastErrCode = FETCH_NETWORK;
206 		break;
207 	case ECONNABORTED:
208 	case ECONNRESET:
209 		fetchLastErrCode = FETCH_ABORT;
210 		break;
211 	case ETIMEDOUT:
212 		fetchLastErrCode = FETCH_TIMEOUT;
213 		break;
214 	case ECONNREFUSED:
215 	case EHOSTDOWN:
216 		fetchLastErrCode = FETCH_DOWN;
217 		break;
218 	default:
219 		fetchLastErrCode = FETCH_UNKNOWN;
220 	}
221 	snprintf(fetchLastErrString, MAXERRSTRING, "%s", strerror(errno));
222 }
223 
224 
225 /*
226  * Emit status message
227  */
228 void
229 fetch_info(const char *fmt, ...)
230 {
231 	va_list ap;
232 	int serrno = errno;
233 
234 	va_start(ap, fmt);
235 	vfprintf(stderr, fmt, ap);
236 	va_end(ap);
237 	fputc('\n', stderr);
238 	errno = serrno;
239 }
240 #define fetch_verbose(...)						\
241 	do { if (verbose) fetch_info(__VA_ARGS__); } while (0)
242 
243 
244 /*** Network-related utility functions ***************************************/
245 
246 /*
247  * Return the default port for a scheme
248  */
249 int
250 fetch_default_port(const char *scheme)
251 {
252 	struct servent *se;
253 
254 	if ((se = getservbyname(scheme, "tcp")) != NULL)
255 		return (ntohs(se->s_port));
256 	if (strcmp(scheme, SCHEME_FTP) == 0)
257 		return (FTP_DEFAULT_PORT);
258 	if (strcmp(scheme, SCHEME_HTTP) == 0)
259 		return (HTTP_DEFAULT_PORT);
260 	return (0);
261 }
262 
263 /*
264  * Return the default proxy port for a scheme
265  */
266 int
267 fetch_default_proxy_port(const char *scheme)
268 {
269 	if (strcmp(scheme, SCHEME_FTP) == 0)
270 		return (FTP_DEFAULT_PROXY_PORT);
271 	if (strcmp(scheme, SCHEME_HTTP) == 0)
272 		return (HTTP_DEFAULT_PROXY_PORT);
273 	return (0);
274 }
275 
276 
277 /*
278  * Create a connection for an existing descriptor.
279  */
280 conn_t *
281 fetch_reopen(int sd)
282 {
283 	conn_t *conn;
284 	int flags;
285 	int opt = 1;
286 
287 	/* allocate and fill connection structure */
288 	if ((conn = calloc(1, sizeof(*conn))) == NULL)
289 		return (NULL);
290 	flags = fcntl(sd, F_GETFD);
291 	if (flags != -1 && (flags & FD_CLOEXEC) == 0)
292 		(void)fcntl(sd, F_SETFD, flags | FD_CLOEXEC);
293 	flags = fcntl(sd, F_GETFL);
294 	if (flags != -1 && (flags & O_NONBLOCK) == 0)
295 		(void)fcntl(sd, F_SETFL, flags | O_NONBLOCK);
296 	(void)setsockopt(sd, SOL_SOCKET, SO_NOSIGPIPE, &opt, sizeof(opt));
297 	conn->sd = sd;
298 	++conn->ref;
299 	return (conn);
300 }
301 
302 
303 /*
304  * Bump a connection's reference count.
305  */
306 conn_t *
307 fetch_ref(conn_t *conn)
308 {
309 	++conn->ref;
310 	return (conn);
311 }
312 
313 
314 /*
315  * Resolve an address
316  */
317 struct addrinfo *
318 fetch_resolve(const char *addr, int port, int af)
319 {
320 	char hbuf[256], sbuf[8];
321 	struct addrinfo hints, *res;
322 	const char *hb, *he, *sep;
323 	const char *host, *service;
324 	int err, len;
325 
326 	/* first, check for a bracketed IPv6 address */
327 	if (*addr == '[') {
328 		hb = addr + 1;
329 		if ((sep = strchr(hb, ']')) == NULL) {
330 			errno = EINVAL;
331 			goto syserr;
332 		}
333 		he = sep++;
334 	} else {
335 		hb = addr;
336 		sep = strchrnul(hb, ':');
337 		he = sep;
338 	}
339 
340 	/* see if we need to copy the host name */
341 	if (*he != '\0') {
342 		len = snprintf(hbuf, sizeof(hbuf),
343 		    "%.*s", (int)(he - hb), hb);
344 		if (len < 0)
345 			goto syserr;
346 		if (len >= (int)sizeof(hbuf)) {
347 			errno = ENAMETOOLONG;
348 			goto syserr;
349 		}
350 		host = hbuf;
351 	} else {
352 		host = hb;
353 	}
354 
355 	/* was it followed by a service name? */
356 	if (*sep == '\0' && port != 0) {
357 		if (port < 1 || port > 65535) {
358 			errno = EINVAL;
359 			goto syserr;
360 		}
361 		if (snprintf(sbuf, sizeof(sbuf), "%d", port) < 0)
362 			goto syserr;
363 		service = sbuf;
364 	} else if (*sep != '\0') {
365 		service = sep + 1;
366 	} else {
367 		service = NULL;
368 	}
369 
370 	/* resolve */
371 	memset(&hints, 0, sizeof(hints));
372 	hints.ai_family = af;
373 	hints.ai_socktype = SOCK_STREAM;
374 	hints.ai_flags = AI_ADDRCONFIG;
375 	if ((err = getaddrinfo(host, service, &hints, &res)) != 0) {
376 		netdb_seterr(err);
377 		return (NULL);
378 	}
379 	return (res);
380 syserr:
381 	fetch_syserr();
382 	return (NULL);
383 }
384 
385 
386 /*
387  * Bind a socket to a specific local address
388  */
389 int
390 fetch_bind(int sd, int af, const char *addr)
391 {
392 	struct addrinfo *cliai, *ai;
393 	int err;
394 
395 	if ((cliai = fetch_resolve(addr, 0, af)) == NULL)
396 		return (-1);
397 	for (ai = cliai; ai != NULL; ai = ai->ai_next)
398 		if ((err = bind(sd, ai->ai_addr, ai->ai_addrlen)) == 0)
399 			break;
400 	if (err != 0)
401 		fetch_syserr();
402 	freeaddrinfo(cliai);
403 	return (err == 0 ? 0 : -1);
404 }
405 
406 
407 /*
408  * SOCKS5 connection initiation, based on RFC 1928
409  * Default DNS resolution over SOCKS5
410  */
411 int
412 fetch_socks5_init(conn_t *conn, const char *host, int port, int verbose)
413 {
414 	/*
415 	 * Size is based on largest packet prefix (4 bytes) +
416 	 * Largest FQDN (256) + one byte size (1) +
417 	 * Port (2)
418 	 */
419 	unsigned char buf[BUFF_SIZE];
420 	unsigned char *ptr;
421 	int ret = 1;
422 
423 	fetch_verbose("Initializing SOCKS5 connection: %s:%d", host, port);
424 
425 	/* Connection initialization */
426 	ptr = buf;
427 	*ptr++ = SOCKS_VERSION_5;
428 	*ptr++ = SOCKS_CONNECTION;
429 	*ptr++ = SOCKS_RSV;
430 
431 	if (fetch_write(conn, buf, 3) != 3) {
432 		ret = SOCKS5_ERR_SELECTION;
433 		goto fail;
434 	}
435 
436 	/* Verify response from SOCKS5 server */
437 	if (fetch_read(conn, buf, 2) != 2) {
438 		ret = SOCKS5_ERR_READ_METHOD;
439 		goto fail;
440 	}
441 
442 	ptr = buf;
443 	if (ptr[0] != SOCKS_VERSION_5) {
444 		ret = SOCKS5_ERR_VER5_ONLY;
445 		goto fail;
446 	}
447 	if (ptr[1] == SOCKS_NOMETHODS) {
448 		ret = SOCKS5_ERR_NOMETHODS;
449 		goto fail;
450 	}
451 	else if (ptr[1] != SOCKS5_NOTIMPLEMENTED) {
452 		ret = SOCKS5_ERR_NOTIMPLEMENTED;
453 		goto fail;
454 	}
455 
456 	/* Send Request */
457 	*ptr++ = SOCKS_VERSION_5;
458 	*ptr++ = SOCKS_CONNECTION;
459 	*ptr++ = SOCKS_RSV;
460 	/* Encode all targets as a hostname to avoid DNS leaks */
461 	*ptr++ = SOCKS_ATYP_DOMAINNAME;
462 	if (strlen(host) > FQDN_SIZE) {
463 		ret = SOCKS5_ERR_HOSTNAME_SIZE;
464 		goto fail;
465 	}
466 	*ptr++ = strlen(host);
467 	memcpy(ptr, host, strlen(host));
468 	ptr = ptr + strlen(host);
469 
470 	port = htons(port);
471 	*ptr++ = port & 0x00ff;
472 	*ptr++ = (port & 0xff00) >> 8;
473 
474 	if (fetch_write(conn, buf, ptr - buf) != ptr - buf) {
475 		ret = SOCKS5_ERR_REQUEST;
476 		goto fail;
477 	}
478 
479 	/* BND.ADDR is variable length, read the largest on non-blocking socket */
480 	if (!fetch_read(conn, buf, BUFF_SIZE)) {
481 		ret = SOCKS5_ERR_REPLY;
482 		goto fail;
483 	}
484 
485 	ptr = buf;
486 	if (*ptr++ != SOCKS_VERSION_5) {
487 		ret = SOCKS5_ERR_NON_VER5_RESP;
488 		goto fail;
489 	}
490 
491 	switch (*ptr++) {
492 	case SOCKS_SUCCESS:
493 		break;
494 	case SOCKS_GENERAL_FAILURE:
495 		ret = SOCKS5_ERR_GENERAL;
496 		goto fail;
497 	case SOCKS_CONNECTION_NOT_ALLOWED:
498 		ret = SOCKS5_ERR_NOT_ALLOWED;
499 		goto fail;
500 	case SOCKS_NETWORK_UNREACHABLE:
501 		ret = SOCKS5_ERR_NET_UNREACHABLE;
502 		goto fail;
503 	case SOCKS_HOST_UNREACHABLE:
504 		ret = SOCKS5_ERR_HOST_UNREACHABLE;
505 		goto fail;
506 	case SOCKS_CONNECTION_REFUSED:
507 		ret = SOCKS5_ERR_CONN_REFUSED;
508 		goto fail;
509 	case SOCKS_TTL_EXPIRED:
510 		ret = SOCKS5_ERR_TTL_EXPIRED;
511 		goto fail;
512 	case SOCKS_COMMAND_NOT_SUPPORTED:
513 		ret = SOCKS5_ERR_COM_UNSUPPORTED;
514 		goto fail;
515 	case SOCKS_ADDRESS_NOT_SUPPORTED:
516 		ret = SOCKS5_ERR_ADDR_UNSUPPORTED;
517 		goto fail;
518 	default:
519 		ret = SOCKS5_ERR_UNSPECIFIED;
520 		goto fail;
521 	}
522 
523 	return (ret);
524 
525 fail:
526 	socks5_seterr(ret);
527 	return (0);
528 }
529 
530 /*
531  * Perform SOCKS5 initialization
532  */
533 int
534 fetch_socks5_getenv(char **host, int *port)
535 {
536 	char *socks5env, *endptr, *ext;
537 	const char *portDelim;
538 	size_t slen;
539 
540 	portDelim = ":";
541 	if ((socks5env = getenv("SOCKS5_PROXY")) == NULL || *socks5env == '\0') {
542 		*host = NULL;
543 		*port = -1;
544 		return (-1);
545 	}
546 
547 	/*
548 	 * IPv6 addresses begin and end in brackets.  Set the port delimiter
549 	 * accordingly and search for it so we can do appropriate validation.
550 	 */
551 	if (socks5env[0] == '[')
552 		portDelim = "]:";
553 
554 	slen = strlen(socks5env);
555 	ext = strstr(socks5env, portDelim);
556 	if (socks5env[0] == '[') {
557 		if (socks5env[slen - 1] == ']') {
558 			*host = strndup(socks5env, slen);
559 		} else if (ext != NULL) {
560 			*host = strndup(socks5env, ext - socks5env + 1);
561 		} else {
562 			socks5_seterr(SOCKS5_ERR_BAD_PROXY_FORMAT);
563 			return (0);
564 		}
565 	} else {
566 		*host = strndup(socks5env, ext - socks5env);
567 	}
568 
569 	if (*host == NULL)
570 		return (-1);
571 	if (ext == NULL) {
572 		*port = 1080; /* Default port as defined in RFC1928 */
573 	} else {
574 		ext += strlen(portDelim);
575 		errno = 0;
576 		*port = strtoimax(ext, (char **)&endptr, 10);
577 		if (*endptr != '\0' || errno != 0 || *port < 0 ||
578 		    *port > 65535) {
579 			free(*host);
580 			*host = NULL;
581 			socks5_seterr(SOCKS5_ERR_BAD_PORT);
582 			return (0);
583 		}
584 	}
585 
586 	return (2);
587 }
588 
589 
590 /*
591  * Establish a TCP connection to the specified port on the specified host.
592  */
593 conn_t *
594 fetch_connect(const char *host, int port, int af, int verbose)
595 {
596 	struct addrinfo *cais = NULL, *sais = NULL, *cai, *sai;
597 	const char *bindaddr;
598 	conn_t *conn = NULL;
599 	int err = 0, sd = -1;
600 	char *sockshost;
601 	int socksport;
602 
603 	DEBUGF("---> %s:%d\n", host, port);
604 
605 	/*
606 	 * Check if SOCKS5_PROXY env variable is set.  fetch_socks5_getenv
607 	 * will either set sockshost = NULL or allocate memory in all cases.
608 	 */
609 	sockshost = NULL;
610 	if (!fetch_socks5_getenv(&sockshost, &socksport))
611 		goto fail;
612 
613 	/* Not using SOCKS5 proxy */
614 	if (sockshost == NULL) {
615 		/* resolve server address */
616 		fetch_verbose("resolving server address: %s:%d", host, port);
617 		if ((sais = fetch_resolve(host, port, af)) == NULL)
618 			goto fail;
619 
620 		/* resolve client address */
621 		bindaddr = getenv("FETCH_BIND_ADDRESS");
622 		if (bindaddr != NULL && *bindaddr != '\0') {
623 			fetch_verbose("resolving client address: %s", bindaddr);
624 			if ((cais = fetch_resolve(bindaddr, 0, af)) == NULL)
625 				goto fail;
626 		}
627 	} else {
628 		/* resolve socks5 proxy address */
629 		fetch_verbose("resolving SOCKS5 server address: %s:%d",
630 		    sockshost, socksport);
631 		if ((sais = fetch_resolve(sockshost, socksport, af)) == NULL) {
632 			socks5_seterr(SOCKS5_ERR_BAD_HOST);
633 			goto fail;
634 		}
635 	}
636 
637 	/* try each server address in turn */
638 	for (err = 0, sai = sais; sai != NULL; sai = sai->ai_next) {
639 		/* open socket */
640 		if ((sd = socket(sai->ai_family, SOCK_STREAM, 0)) < 0) {
641 			err = -1;
642 			if (errno == EAFNOSUPPORT || errno == EPROTONOSUPPORT)
643 				continue;
644 			goto syserr;
645 		}
646 		/* attempt to bind to client address */
647 		for (err = 0, cai = cais; cai != NULL; cai = cai->ai_next) {
648 			if (cai->ai_family != sai->ai_family)
649 				continue;
650 			if ((err = bind(sd, cai->ai_addr, cai->ai_addrlen)) == 0)
651 				break;
652 		}
653 		if (err != 0) {
654 			fetch_verbose("failed to bind to %s", bindaddr);
655 			goto syserr;
656 		}
657 		/* attempt to connect to server address */
658 		while ((err = connect(sd, sai->ai_addr, sai->ai_addrlen)) < 0) {
659 			if (errno == EINTR && fetchRestartCalls)
660 				continue;
661 			break;
662 		}
663 		/* success? */
664 		if (err == 0)
665 			break;
666 		/* clean up before next attempt */
667 		close(sd);
668 		sd = -1;
669 	}
670 	if (err != 0) {
671 		if (verbose && sockshost == NULL) {
672 			fetch_info("failed to connect to %s:%d", host, port);
673 			goto syserr;
674 		} else if (sockshost != NULL) {
675 			fetch_verbose("failed to connect to SOCKS5 server %s:%d",
676 			    sockshost, socksport);
677 			socks5_seterr(SOCKS5_ERR_CONN_REFUSED);
678 			goto fail;
679 		}
680 		goto syserr;
681 	}
682 
683 	if ((conn = fetch_reopen(sd)) == NULL)
684 		goto syserr;
685 
686 	if (sockshost)
687 		if (!fetch_socks5_init(conn, host, port, verbose))
688 			goto fail;
689 	free(sockshost);
690 	if (cais != NULL)
691 		freeaddrinfo(cais);
692 	if (sais != NULL)
693 		freeaddrinfo(sais);
694 	return (conn);
695 syserr:
696 	fetch_syserr();
697 fail:
698 	free(sockshost);
699 	/* Fully close if it was opened; otherwise just don't leak the fd. */
700 	if (conn != NULL)
701 		fetch_close(conn);
702 	else if (sd >= 0)
703 		close(sd);
704 	if (cais != NULL)
705 		freeaddrinfo(cais);
706 	if (sais != NULL)
707 		freeaddrinfo(sais);
708 	return (NULL);
709 }
710 
711 #ifdef WITH_SSL
712 /*
713  * Convert characters A-Z to lowercase (intentionally avoid any locale
714  * specific conversions).
715  */
716 static char
717 fetch_ssl_tolower(char in)
718 {
719 	if (in >= 'A' && in <= 'Z')
720 		return (in + 32);
721 	else
722 		return (in);
723 }
724 
725 /*
726  * isalpha implementation that intentionally avoids any locale specific
727  * conversions.
728  */
729 static int
730 fetch_ssl_isalpha(char in)
731 {
732 	return ((in >= 'A' && in <= 'Z') || (in >= 'a' && in <= 'z'));
733 }
734 
735 /*
736  * Check if passed hostnames a and b are equal.
737  */
738 static int
739 fetch_ssl_hname_equal(const char *a, size_t alen, const char *b,
740     size_t blen)
741 {
742 	size_t i;
743 
744 	if (alen != blen)
745 		return (0);
746 	for (i = 0; i < alen; ++i) {
747 		if (fetch_ssl_tolower(a[i]) != fetch_ssl_tolower(b[i]))
748 			return (0);
749 	}
750 	return (1);
751 }
752 
753 /*
754  * Check if domain label is traditional, meaning that only A-Z, a-z, 0-9
755  * and '-' (hyphen) are allowed. Hyphens have to be surrounded by alpha-
756  * numeric characters. Double hyphens (like they're found in IDN a-labels
757  * 'xn--') are not allowed. Empty labels are invalid.
758  */
759 static int
760 fetch_ssl_is_trad_domain_label(const char *l, size_t len, int wcok)
761 {
762 	size_t i;
763 
764 	if (!len || l[0] == '-' || l[len-1] == '-')
765 		return (0);
766 	for (i = 0; i < len; ++i) {
767 		if (!isdigit(l[i]) &&
768 		    !fetch_ssl_isalpha(l[i]) &&
769 		    !(l[i] == '*' && wcok) &&
770 		    !(l[i] == '-' && l[i - 1] != '-'))
771 			return (0);
772 	}
773 	return (1);
774 }
775 
776 /*
777  * Check if host name consists only of numbers. This might indicate an IP
778  * address, which is not a good idea for CN wildcard comparison.
779  */
780 static int
781 fetch_ssl_hname_is_only_numbers(const char *hostname, size_t len)
782 {
783 	size_t i;
784 
785 	for (i = 0; i < len; ++i) {
786 		if (!((hostname[i] >= '0' && hostname[i] <= '9') ||
787 		    hostname[i] == '.'))
788 			return (0);
789 	}
790 	return (1);
791 }
792 
793 /*
794  * Check if the host name h passed matches the pattern passed in m which
795  * is usually part of subjectAltName or CN of a certificate presented to
796  * the client. This includes wildcard matching. The algorithm is based on
797  * RFC6125, sections 6.4.3 and 7.2, which clarifies RFC2818 and RFC3280.
798  */
799 static int
800 fetch_ssl_hname_match(const char *h, size_t hlen, const char *m,
801     size_t mlen)
802 {
803 	int delta, hdotidx, mdot1idx, wcidx;
804 	const char *hdot, *mdot1, *mdot2;
805 	const char *wc; /* wildcard */
806 
807 	if (!(h && *h && m && *m))
808 		return (0);
809 	if ((wc = strnstr(m, "*", mlen)) == NULL)
810 		return (fetch_ssl_hname_equal(h, hlen, m, mlen));
811 	wcidx = wc - m;
812 	/* hostname should not be just dots and numbers */
813 	if (fetch_ssl_hname_is_only_numbers(h, hlen))
814 		return (0);
815 	/* only one wildcard allowed in pattern */
816 	if (strnstr(wc + 1, "*", mlen - wcidx - 1) != NULL)
817 		return (0);
818 	/*
819 	 * there must be at least two more domain labels and
820 	 * wildcard has to be in the leftmost label (RFC6125)
821 	 */
822 	mdot1 = strnstr(m, ".", mlen);
823 	if (mdot1 == NULL || mdot1 < wc || (mlen - (mdot1 - m)) < 4)
824 		return (0);
825 	mdot1idx = mdot1 - m;
826 	mdot2 = strnstr(mdot1 + 1, ".", mlen - mdot1idx - 1);
827 	if (mdot2 == NULL || (mlen - (mdot2 - m)) < 2)
828 		return (0);
829 	/* hostname must contain a dot and not be the 1st char */
830 	hdot = strnstr(h, ".", hlen);
831 	if (hdot == NULL || hdot == h)
832 		return (0);
833 	hdotidx = hdot - h;
834 	/*
835 	 * host part of hostname must be at least as long as
836 	 * pattern it's supposed to match
837 	 */
838 	if (hdotidx < mdot1idx)
839 		return (0);
840 	/*
841 	 * don't allow wildcards in non-traditional domain names
842 	 * (IDN, A-label, U-label...)
843 	 */
844 	if (!fetch_ssl_is_trad_domain_label(h, hdotidx, 0) ||
845 	    !fetch_ssl_is_trad_domain_label(m, mdot1idx, 1))
846 		return (0);
847 	/* match domain part (part after first dot) */
848 	if (!fetch_ssl_hname_equal(hdot, hlen - hdotidx, mdot1,
849 	    mlen - mdot1idx))
850 		return (0);
851 	/* match part left of wildcard */
852 	if (!fetch_ssl_hname_equal(h, wcidx, m, wcidx))
853 		return (0);
854 	/* match part right of wildcard */
855 	delta = mdot1idx - wcidx - 1;
856 	if (!fetch_ssl_hname_equal(hdot - delta, delta,
857 	    mdot1 - delta, delta))
858 		return (0);
859 	/* all tests succeeded, it's a match */
860 	return (1);
861 }
862 
863 /*
864  * Get numeric host address info - returns NULL if host was not an IP
865  * address. The caller is responsible for deallocation using
866  * freeaddrinfo(3).
867  */
868 static struct addrinfo *
869 fetch_ssl_get_numeric_addrinfo(const char *hostname, size_t len)
870 {
871 	struct addrinfo hints, *res;
872 	char *host;
873 
874 	host = (char *)malloc(len + 1);
875 	memcpy(host, hostname, len);
876 	host[len] = '\0';
877 	memset(&hints, 0, sizeof(hints));
878 	hints.ai_family = PF_UNSPEC;
879 	hints.ai_socktype = SOCK_STREAM;
880 	hints.ai_protocol = 0;
881 	hints.ai_flags = AI_NUMERICHOST;
882 	/* port is not relevant for this purpose */
883 	if (getaddrinfo(host, "443", &hints, &res) != 0)
884 		res = NULL;
885 	free(host);
886 	return res;
887 }
888 
889 /*
890  * Compare ip address in addrinfo with address passes.
891  */
892 static int
893 fetch_ssl_ipaddr_match_bin(const struct addrinfo *lhost, const char *rhost,
894     size_t rhostlen)
895 {
896 	const void *left;
897 
898 	if (lhost->ai_family == AF_INET && rhostlen == 4) {
899 		left = (void *)&((struct sockaddr_in*)(void *)
900 		    lhost->ai_addr)->sin_addr.s_addr;
901 #ifdef INET6
902 	} else if (lhost->ai_family == AF_INET6 && rhostlen == 16) {
903 		left = (void *)&((struct sockaddr_in6 *)(void *)
904 		    lhost->ai_addr)->sin6_addr;
905 #endif
906 	} else
907 		return (0);
908 	return (!memcmp(left, (const void *)rhost, rhostlen) ? 1 : 0);
909 }
910 
911 /*
912  * Compare ip address in addrinfo with host passed. If host is not an IP
913  * address, comparison will fail.
914  */
915 static int
916 fetch_ssl_ipaddr_match(const struct addrinfo *laddr, const char *r,
917     size_t rlen)
918 {
919 	struct addrinfo *raddr;
920 	int ret;
921 	char *rip;
922 
923 	ret = 0;
924 	if ((raddr = fetch_ssl_get_numeric_addrinfo(r, rlen)) == NULL)
925 		return 0; /* not a numeric host */
926 
927 	if (laddr->ai_family == raddr->ai_family) {
928 		if (laddr->ai_family == AF_INET) {
929 			rip = (char *)&((struct sockaddr_in *)(void *)
930 			    raddr->ai_addr)->sin_addr.s_addr;
931 			ret = fetch_ssl_ipaddr_match_bin(laddr, rip, 4);
932 #ifdef INET6
933 		} else if (laddr->ai_family == AF_INET6) {
934 			rip = (char *)&((struct sockaddr_in6 *)(void *)
935 			    raddr->ai_addr)->sin6_addr;
936 			ret = fetch_ssl_ipaddr_match_bin(laddr, rip, 16);
937 #endif
938 		}
939 
940 	}
941 	freeaddrinfo(raddr);
942 	return (ret);
943 }
944 
945 /*
946  * Verify server certificate by subjectAltName.
947  */
948 static int
949 fetch_ssl_verify_altname(STACK_OF(GENERAL_NAME) *altnames,
950     const char *host, struct addrinfo *ip)
951 {
952 	const GENERAL_NAME *name;
953 	size_t nslen;
954 	int i;
955 	const char *ns;
956 
957 	for (i = 0; i < sk_GENERAL_NAME_num(altnames); ++i) {
958 		name = sk_GENERAL_NAME_value(altnames, i);
959 		ns = (const char *)ASN1_STRING_get0_data(name->d.ia5);
960 		nslen = (size_t)ASN1_STRING_length(name->d.ia5);
961 
962 		if (name->type == GEN_DNS && ip == NULL &&
963 		    fetch_ssl_hname_match(host, strlen(host), ns, nslen))
964 			return (1);
965 		else if (name->type == GEN_IPADD && ip != NULL &&
966 		    fetch_ssl_ipaddr_match_bin(ip, ns, nslen))
967 			return (1);
968 	}
969 	return (0);
970 }
971 
972 /*
973  * Verify server certificate by CN.
974  */
975 static int
976 fetch_ssl_verify_cn(X509_NAME *subject, const char *host,
977     struct addrinfo *ip)
978 {
979 	ASN1_STRING *namedata;
980 	X509_NAME_ENTRY *nameentry;
981 	int cnlen, lastpos, loc, ret;
982 	unsigned char *cn;
983 
984 	ret = 0;
985 	lastpos = -1;
986 	loc = -1;
987 	cn = NULL;
988 	/* get most specific CN (last entry in list) and compare */
989 	while ((lastpos = X509_NAME_get_index_by_NID(subject,
990 	    NID_commonName, lastpos)) != -1)
991 		loc = lastpos;
992 
993 	if (loc > -1) {
994 		nameentry = X509_NAME_get_entry(subject, loc);
995 		namedata = X509_NAME_ENTRY_get_data(nameentry);
996 		cnlen = ASN1_STRING_to_UTF8(&cn, namedata);
997 		if (ip == NULL &&
998 		    fetch_ssl_hname_match(host, strlen(host), cn, cnlen))
999 			ret = 1;
1000 		else if (ip != NULL && fetch_ssl_ipaddr_match(ip, cn, cnlen))
1001 			ret = 1;
1002 		OPENSSL_free(cn);
1003 	}
1004 	return (ret);
1005 }
1006 
1007 /*
1008  * Verify that server certificate subjectAltName/CN matches
1009  * hostname. First check, if there are alternative subject names. If yes,
1010  * those have to match. Only if those don't exist it falls back to
1011  * checking the subject's CN.
1012  */
1013 static int
1014 fetch_ssl_verify_hname(X509 *cert, const char *host)
1015 {
1016 	struct addrinfo *ip;
1017 	STACK_OF(GENERAL_NAME) *altnames;
1018 	X509_NAME *subject;
1019 	int ret;
1020 
1021 	ret = 0;
1022 	ip = fetch_ssl_get_numeric_addrinfo(host, strlen(host));
1023 	altnames = X509_get_ext_d2i(cert, NID_subject_alt_name,
1024 	    NULL, NULL);
1025 
1026 	if (altnames != NULL) {
1027 		ret = fetch_ssl_verify_altname(altnames, host, ip);
1028 	} else {
1029 		subject = X509_get_subject_name(cert);
1030 		if (subject != NULL)
1031 			ret = fetch_ssl_verify_cn(subject, host, ip);
1032 	}
1033 
1034 	if (ip != NULL)
1035 		freeaddrinfo(ip);
1036 	if (altnames != NULL)
1037 		GENERAL_NAMES_free(altnames);
1038 	return (ret);
1039 }
1040 
1041 /*
1042  * Configure transport security layer based on environment.
1043  */
1044 static void
1045 fetch_ssl_setup_transport_layer(SSL_CTX *ctx, int verbose)
1046 {
1047 	long ssl_ctx_options;
1048 
1049 	ssl_ctx_options = SSL_OP_ALL | SSL_OP_NO_SSLv3 | SSL_OP_NO_TICKET;
1050 	if (getenv("SSL_NO_TLS1") != NULL)
1051 		ssl_ctx_options |= SSL_OP_NO_TLSv1;
1052 	if (getenv("SSL_NO_TLS1_1") != NULL)
1053 		ssl_ctx_options |= SSL_OP_NO_TLSv1_1;
1054 	if (getenv("SSL_NO_TLS1_2") != NULL)
1055 		ssl_ctx_options |= SSL_OP_NO_TLSv1_2;
1056 	if (getenv("SSL_NO_TLS1_3") != NULL)
1057 		ssl_ctx_options |= SSL_OP_NO_TLSv1_3;
1058 	fetch_verbose("SSL options: %lx", ssl_ctx_options);
1059 	SSL_CTX_set_options(ctx, ssl_ctx_options);
1060 }
1061 
1062 
1063 /*
1064  * Configure peer verification based on environment.
1065  */
1066 static int
1067 fetch_ssl_setup_peer_verification(SSL_CTX *ctx, int verbose)
1068 {
1069 	X509_LOOKUP *crl_lookup;
1070 	X509_STORE *crl_store;
1071 	const char *ca_cert_file, *ca_cert_path, *crl_file;
1072 
1073 	if (getenv("SSL_NO_VERIFY_PEER") == NULL) {
1074 		ca_cert_file = getenv("SSL_CA_CERT_FILE");
1075 		ca_cert_path = getenv("SSL_CA_CERT_PATH");
1076 		if (verbose) {
1077 			fetch_info("Peer verification enabled");
1078 			if (ca_cert_file != NULL)
1079 				fetch_info("Using CA cert file: %s",
1080 				    ca_cert_file);
1081 			if (ca_cert_path != NULL)
1082 				fetch_info("Using CA cert path: %s",
1083 				    ca_cert_path);
1084 			if (ca_cert_file == NULL && ca_cert_path == NULL)
1085 				fetch_info("Using OpenSSL default "
1086 				    "CA cert file and path");
1087 		}
1088 		SSL_CTX_set_verify(ctx, SSL_VERIFY_PEER,
1089 		    fetch_ssl_cb_verify_crt);
1090 		if (ca_cert_file != NULL || ca_cert_path != NULL)
1091 			SSL_CTX_load_verify_locations(ctx, ca_cert_file,
1092 			    ca_cert_path);
1093 		else
1094 			SSL_CTX_set_default_verify_paths(ctx);
1095 		if ((crl_file = getenv("SSL_CRL_FILE")) != NULL) {
1096 			fetch_verbose("Using CRL file: %s", crl_file);
1097 			crl_store = SSL_CTX_get_cert_store(ctx);
1098 			crl_lookup = X509_STORE_add_lookup(crl_store,
1099 			    X509_LOOKUP_file());
1100 			if (crl_lookup == NULL ||
1101 			    !X509_load_crl_file(crl_lookup, crl_file,
1102 				X509_FILETYPE_PEM)) {
1103 				fetch_info("Could not load CRL file %s",
1104 				    crl_file);
1105 				return (0);
1106 			}
1107 			X509_STORE_set_flags(crl_store,
1108 			    X509_V_FLAG_CRL_CHECK |
1109 			    X509_V_FLAG_CRL_CHECK_ALL);
1110 		}
1111 	}
1112 	return (1);
1113 }
1114 
1115 /*
1116  * Configure client certificate based on environment.
1117  */
1118 static int
1119 fetch_ssl_setup_client_certificate(SSL_CTX *ctx, int verbose)
1120 {
1121 	const char *client_cert_file, *client_key_file;
1122 
1123 	if ((client_cert_file = getenv("SSL_CLIENT_CERT_FILE")) != NULL) {
1124 		client_key_file = getenv("SSL_CLIENT_KEY_FILE") != NULL ?
1125 		    getenv("SSL_CLIENT_KEY_FILE") : client_cert_file;
1126 		fetch_verbose("Using client cert file: %s", client_cert_file);
1127 		fetch_verbose("Using client key file: %s", client_key_file);
1128 		if (SSL_CTX_use_certificate_chain_file(ctx,
1129 			client_cert_file) != 1) {
1130 			fetch_info("Could not load client certificate %s",
1131 			    client_cert_file);
1132 			return (0);
1133 		}
1134 		if (SSL_CTX_use_PrivateKey_file(ctx, client_key_file,
1135 			SSL_FILETYPE_PEM) != 1) {
1136 			fetch_info("Could not load client key %s",
1137 			    client_key_file);
1138 			return (0);
1139 		}
1140 	}
1141 	return (1);
1142 }
1143 
1144 /*
1145  * Callback for SSL certificate verification, this is called on server
1146  * cert verification. It takes no decision, but informs the user in case
1147  * verification failed.
1148  */
1149 int
1150 fetch_ssl_cb_verify_crt(int verified, X509_STORE_CTX *ctx)
1151 {
1152 	X509 *crt;
1153 	X509_NAME *name;
1154 	char *str;
1155 
1156 	str = NULL;
1157 	if (!verified) {
1158 		if ((crt = X509_STORE_CTX_get_current_cert(ctx)) != NULL &&
1159 		    (name = X509_get_subject_name(crt)) != NULL)
1160 			str = X509_NAME_oneline(name, 0, 0);
1161 		fetch_info("Certificate verification failed for %s",
1162 		    str != NULL ? str : "no relevant certificate");
1163 		OPENSSL_free(str);
1164 	}
1165 	return (verified);
1166 }
1167 
1168 #endif
1169 
1170 /*
1171  * Enable SSL on a connection.
1172  */
1173 int
1174 fetch_ssl(conn_t *conn, const struct url *URL, int verbose)
1175 {
1176 #ifdef WITH_SSL
1177 	int ret, ssl_err;
1178 	X509_NAME *name;
1179 	char *str;
1180 
1181 	if ((conn->ssl_ctx = SSL_CTX_new(TLS_client_method())) == NULL) {
1182 		fetch_info("SSL context creation failed");
1183 		ERR_print_errors_fp(stderr);
1184 		return (-1);
1185 	}
1186 	SSL_CTX_set_mode(conn->ssl_ctx, SSL_MODE_AUTO_RETRY);
1187 
1188 	fetch_ssl_setup_transport_layer(conn->ssl_ctx, verbose);
1189 	if (!fetch_ssl_setup_peer_verification(conn->ssl_ctx, verbose))
1190 		return (-1);
1191 	if (!fetch_ssl_setup_client_certificate(conn->ssl_ctx, verbose))
1192 		return (-1);
1193 
1194 	conn->ssl = SSL_new(conn->ssl_ctx);
1195 	if (conn->ssl == NULL) {
1196 		fetch_info("SSL connection creation failed");
1197 		ERR_print_errors_fp(stderr);
1198 		return (-1);
1199 	}
1200 	SSL_set_fd(conn->ssl, conn->sd);
1201 
1202 #if !defined(OPENSSL_NO_TLSEXT)
1203 	if (!SSL_set_tlsext_host_name(conn->ssl, __DECONST(char *, URL->host))) {
1204 		fetch_info("Failed to set TLS server name indication for host %s",
1205 		    URL->host);
1206 		return (-1);
1207 	}
1208 #endif
1209 	while ((ret = SSL_connect(conn->ssl)) == -1) {
1210 		ssl_err = SSL_get_error(conn->ssl, ret);
1211 		if (ssl_err != SSL_ERROR_WANT_READ &&
1212 		    ssl_err != SSL_ERROR_WANT_WRITE) {
1213 			ERR_print_errors_fp(stderr);
1214 			return (-1);
1215 		}
1216 	}
1217 	conn->ssl_cert = SSL_get_peer_certificate(conn->ssl);
1218 
1219 	if (conn->ssl_cert == NULL) {
1220 		fetch_info("No server SSL certificate");
1221 		return (-1);
1222 	}
1223 
1224 	if (getenv("SSL_NO_VERIFY_HOSTNAME") == NULL) {
1225 		fetch_verbose("Verify hostname");
1226 		if (!fetch_ssl_verify_hname(conn->ssl_cert, URL->host)) {
1227 			fetch_info("SSL certificate subject does not match host %s",
1228 			    URL->host);
1229 			return (-1);
1230 		}
1231 	}
1232 
1233 	if (verbose) {
1234 		fetch_info("%s connection established using %s",
1235 		    SSL_get_version(conn->ssl), SSL_get_cipher(conn->ssl));
1236 		name = X509_get_subject_name(conn->ssl_cert);
1237 		str = X509_NAME_oneline(name, 0, 0);
1238 		fetch_info("Certificate subject: %s", str);
1239 		OPENSSL_free(str);
1240 		name = X509_get_issuer_name(conn->ssl_cert);
1241 		str = X509_NAME_oneline(name, 0, 0);
1242 		fetch_info("Certificate issuer: %s", str);
1243 		OPENSSL_free(str);
1244 	}
1245 
1246 	return (0);
1247 #else
1248 	(void)conn;
1249 	(void)verbose;
1250 	(void)URL;
1251 	fetch_info("SSL support disabled");
1252 	return (-1);
1253 #endif
1254 }
1255 
1256 #define FETCH_READ_WAIT		-2
1257 #define FETCH_READ_ERROR	-1
1258 #define FETCH_READ_DONE		 0
1259 
1260 #ifdef WITH_SSL
1261 static ssize_t
1262 fetch_ssl_read(SSL *ssl, char *buf, size_t len)
1263 {
1264 	ssize_t rlen;
1265 	int ssl_err;
1266 
1267 	rlen = SSL_read(ssl, buf, len);
1268 	if (rlen < 0) {
1269 		ssl_err = SSL_get_error(ssl, rlen);
1270 		if (ssl_err == SSL_ERROR_WANT_READ ||
1271 		    ssl_err == SSL_ERROR_WANT_WRITE) {
1272 			return (FETCH_READ_WAIT);
1273 		} else {
1274 			ERR_print_errors_fp(stderr);
1275 			return (FETCH_READ_ERROR);
1276 		}
1277 	}
1278 	return (rlen);
1279 }
1280 #endif
1281 
1282 static ssize_t
1283 fetch_socket_read(int sd, char *buf, size_t len)
1284 {
1285 	ssize_t rlen;
1286 
1287 	rlen = read(sd, buf, len);
1288 	if (rlen < 0) {
1289 		if (errno == EAGAIN || (errno == EINTR && fetchRestartCalls)) {
1290 			return (FETCH_READ_WAIT);
1291 		} else {
1292 			return (FETCH_READ_ERROR);
1293 		}
1294 	}
1295 	return (rlen);
1296 }
1297 
1298 /*
1299  * Read a character from a connection w/ timeout
1300  */
1301 ssize_t
1302 fetch_read(conn_t *conn, char *buf, size_t len)
1303 {
1304 	struct timeval now, timeout, delta;
1305 	struct pollfd pfd;
1306 	ssize_t rlen;
1307 	int deltams;
1308 
1309 	if (fetchTimeout > 0) {
1310 		gettimeofday(&timeout, NULL);
1311 		timeout.tv_sec += fetchTimeout;
1312 	}
1313 
1314 	deltams = INFTIM;
1315 	memset(&pfd, 0, sizeof pfd);
1316 	pfd.fd = conn->sd;
1317 	pfd.events = POLLIN | POLLERR;
1318 
1319 	for (;;) {
1320 		/*
1321 		 * The socket is non-blocking.  Instead of the canonical
1322 		 * poll() -> read(), we do the following:
1323 		 *
1324 		 * 1) call read() or SSL_read().
1325 		 * 2) if we received some data, return it.
1326 		 * 3) if an error occurred, return -1.
1327 		 * 4) if read() or SSL_read() signaled EOF, return.
1328 		 * 5) if we did not receive any data but we're not at EOF,
1329 		 *    call poll().
1330 		 *
1331 		 * In the SSL case, this is necessary because if we
1332 		 * receive a close notification, we have to call
1333 		 * SSL_read() one additional time after we've read
1334 		 * everything we received.
1335 		 *
1336 		 * In the non-SSL case, it may improve performance (very
1337 		 * slightly) when reading small amounts of data.
1338 		 */
1339 #ifdef WITH_SSL
1340 		if (conn->ssl != NULL)
1341 			rlen = fetch_ssl_read(conn->ssl, buf, len);
1342 		else
1343 #endif
1344 			rlen = fetch_socket_read(conn->sd, buf, len);
1345 		if (rlen >= 0) {
1346 			break;
1347 		} else if (rlen == FETCH_READ_ERROR) {
1348 			fetch_syserr();
1349 			return (-1);
1350 		}
1351 		// assert(rlen == FETCH_READ_WAIT);
1352 		if (fetchTimeout > 0) {
1353 			gettimeofday(&now, NULL);
1354 			if (!timercmp(&timeout, &now, >)) {
1355 				errno = ETIMEDOUT;
1356 				fetch_syserr();
1357 				return (-1);
1358 			}
1359 			timersub(&timeout, &now, &delta);
1360 			deltams = delta.tv_sec * 1000 +
1361 			    delta.tv_usec / 1000;
1362 		}
1363 		errno = 0;
1364 		pfd.revents = 0;
1365 		if (poll(&pfd, 1, deltams) < 0) {
1366 			if (errno == EINTR && fetchRestartCalls)
1367 				continue;
1368 			fetch_syserr();
1369 			return (-1);
1370 		}
1371 	}
1372 	return (rlen);
1373 }
1374 
1375 
1376 /*
1377  * Read a line of text from a connection w/ timeout
1378  */
1379 #define MIN_BUF_SIZE 1024
1380 
1381 int
1382 fetch_getln(conn_t *conn)
1383 {
1384 	char *tmp;
1385 	size_t tmpsize;
1386 	ssize_t len;
1387 	char c;
1388 
1389 	if (conn->buf == NULL) {
1390 		if ((conn->buf = malloc(MIN_BUF_SIZE)) == NULL) {
1391 			errno = ENOMEM;
1392 			return (-1);
1393 		}
1394 		conn->bufsize = MIN_BUF_SIZE;
1395 	}
1396 
1397 	conn->buf[0] = '\0';
1398 	conn->buflen = 0;
1399 
1400 	do {
1401 		len = fetch_read(conn, &c, 1);
1402 		if (len == -1)
1403 			return (-1);
1404 		if (len == 0)
1405 			break;
1406 		conn->buf[conn->buflen++] = c;
1407 		if (conn->buflen == conn->bufsize) {
1408 			tmp = conn->buf;
1409 			tmpsize = conn->bufsize * 2 + 1;
1410 			if ((tmp = realloc(tmp, tmpsize)) == NULL) {
1411 				errno = ENOMEM;
1412 				return (-1);
1413 			}
1414 			conn->buf = tmp;
1415 			conn->bufsize = tmpsize;
1416 		}
1417 	} while (c != '\n');
1418 
1419 	conn->buf[conn->buflen] = '\0';
1420 	DEBUGF("<<< %s", conn->buf);
1421 	return (0);
1422 }
1423 
1424 
1425 /*
1426  * Write to a connection w/ timeout
1427  */
1428 ssize_t
1429 fetch_write(conn_t *conn, const char *buf, size_t len)
1430 {
1431 	struct iovec iov;
1432 
1433 	iov.iov_base = __DECONST(char *, buf);
1434 	iov.iov_len = len;
1435 	return (fetch_writev(conn, &iov, 1));
1436 }
1437 
1438 /*
1439  * Write a vector to a connection w/ timeout
1440  * Note: can modify the iovec.
1441  */
1442 ssize_t
1443 fetch_writev(conn_t *conn, struct iovec *iov, int iovcnt)
1444 {
1445 	struct timeval now, timeout, delta;
1446 	struct pollfd pfd;
1447 	ssize_t wlen, total;
1448 	int deltams;
1449 
1450 	memset(&pfd, 0, sizeof pfd);
1451 	if (fetchTimeout) {
1452 		pfd.fd = conn->sd;
1453 		pfd.events = POLLOUT | POLLERR;
1454 		gettimeofday(&timeout, NULL);
1455 		timeout.tv_sec += fetchTimeout;
1456 	}
1457 
1458 	total = 0;
1459 	while (iovcnt > 0) {
1460 		while (fetchTimeout && pfd.revents == 0) {
1461 			gettimeofday(&now, NULL);
1462 			if (!timercmp(&timeout, &now, >)) {
1463 				errno = ETIMEDOUT;
1464 				fetch_syserr();
1465 				return (-1);
1466 			}
1467 			timersub(&timeout, &now, &delta);
1468 			deltams = delta.tv_sec * 1000 +
1469 			    delta.tv_usec / 1000;
1470 			errno = 0;
1471 			pfd.revents = 0;
1472 			if (poll(&pfd, 1, deltams) < 0) {
1473 				/* POSIX compliance */
1474 				if (errno == EAGAIN)
1475 					continue;
1476 				if (errno == EINTR && fetchRestartCalls)
1477 					continue;
1478 				return (-1);
1479 			}
1480 		}
1481 		errno = 0;
1482 #ifdef WITH_SSL
1483 		if (conn->ssl != NULL)
1484 			wlen = SSL_write(conn->ssl,
1485 			    iov->iov_base, iov->iov_len);
1486 		else
1487 #endif
1488 			wlen = writev(conn->sd, iov, iovcnt);
1489 		if (wlen == 0) {
1490 			/* we consider a short write a failure */
1491 			/* XXX perhaps we shouldn't in the SSL case */
1492 			errno = EPIPE;
1493 			fetch_syserr();
1494 			return (-1);
1495 		}
1496 		if (wlen < 0) {
1497 			if (errno == EINTR && fetchRestartCalls)
1498 				continue;
1499 			return (-1);
1500 		}
1501 		total += wlen;
1502 		while (iovcnt > 0 && wlen >= (ssize_t)iov->iov_len) {
1503 			wlen -= iov->iov_len;
1504 			iov++;
1505 			iovcnt--;
1506 		}
1507 		if (iovcnt > 0) {
1508 			iov->iov_len -= wlen;
1509 			iov->iov_base = __DECONST(char *, iov->iov_base) + wlen;
1510 		}
1511 	}
1512 	return (total);
1513 }
1514 
1515 
1516 /*
1517  * Write a line of text to a connection w/ timeout
1518  */
1519 int
1520 fetch_putln(conn_t *conn, const char *str, size_t len)
1521 {
1522 	struct iovec iov[2];
1523 	int ret;
1524 
1525 	DEBUGF(">>> %s\n", str);
1526 	iov[0].iov_base = __DECONST(char *, str);
1527 	iov[0].iov_len = len;
1528 	iov[1].iov_base = __DECONST(char *, ENDL);
1529 	iov[1].iov_len = sizeof(ENDL);
1530 	if (len == 0)
1531 		ret = fetch_writev(conn, &iov[1], 1);
1532 	else
1533 		ret = fetch_writev(conn, iov, 2);
1534 	if (ret == -1)
1535 		return (-1);
1536 	return (0);
1537 }
1538 
1539 
1540 /*
1541  * Close connection
1542  */
1543 int
1544 fetch_close(conn_t *conn)
1545 {
1546 	int ret;
1547 
1548 	if (--conn->ref > 0)
1549 		return (0);
1550 #ifdef WITH_SSL
1551 	if (conn->ssl) {
1552 		SSL_shutdown(conn->ssl);
1553 		SSL_set_connect_state(conn->ssl);
1554 		SSL_free(conn->ssl);
1555 		conn->ssl = NULL;
1556 	}
1557 	if (conn->ssl_ctx) {
1558 		SSL_CTX_free(conn->ssl_ctx);
1559 		conn->ssl_ctx = NULL;
1560 	}
1561 	if (conn->ssl_cert) {
1562 		X509_free(conn->ssl_cert);
1563 		conn->ssl_cert = NULL;
1564 	}
1565 #endif
1566 	ret = close(conn->sd);
1567 	free(conn->buf);
1568 	free(conn);
1569 	return (ret);
1570 }
1571 
1572 
1573 /*** Directory-related utility functions *************************************/
1574 
1575 int
1576 fetch_add_entry(struct url_ent **p, int *size, int *len,
1577     const char *name, struct url_stat *us)
1578 {
1579 	struct url_ent *tmp;
1580 
1581 	if (*p == NULL) {
1582 		*size = 0;
1583 		*len = 0;
1584 	}
1585 
1586 	if (*len >= *size - 1) {
1587 		tmp = reallocarray(*p, *size * 2 + 1, sizeof(**p));
1588 		if (tmp == NULL) {
1589 			errno = ENOMEM;
1590 			fetch_syserr();
1591 			return (-1);
1592 		}
1593 		*size = (*size * 2 + 1);
1594 		*p = tmp;
1595 	}
1596 
1597 	tmp = *p + *len;
1598 	snprintf(tmp->name, PATH_MAX, "%s", name);
1599 	memcpy(&tmp->stat, us, sizeof(*us));
1600 
1601 	(*len)++;
1602 	(++tmp)->name[0] = 0;
1603 
1604 	return (0);
1605 }
1606 
1607 
1608 /*** Authentication-related utility functions ********************************/
1609 
1610 static const char *
1611 fetch_read_word(FILE *f)
1612 {
1613 	static char word[1024];
1614 
1615 	if (fscanf(f, " %1023s ", word) != 1)
1616 		return (NULL);
1617 	return (word);
1618 }
1619 
1620 static int
1621 fetch_netrc_open(void)
1622 {
1623 	struct passwd *pwd;
1624 	char fn[PATH_MAX];
1625 	const char *p;
1626 	int fd, serrno;
1627 
1628 	if ((p = getenv("NETRC")) != NULL) {
1629 		DEBUGF("NETRC=%s\n", p);
1630 		if (snprintf(fn, sizeof(fn), "%s", p) >= (int)sizeof(fn)) {
1631 			fetch_info("$NETRC specifies a file name "
1632 			    "longer than PATH_MAX");
1633 			return (-1);
1634 		}
1635 	} else {
1636 		if ((p = getenv("HOME")) == NULL) {
1637 			if ((pwd = getpwuid(getuid())) == NULL ||
1638 			    (p = pwd->pw_dir) == NULL)
1639 				return (-1);
1640 		}
1641 		if (snprintf(fn, sizeof(fn), "%s/.netrc", p) >= (int)sizeof(fn))
1642 			return (-1);
1643 	}
1644 
1645 	if ((fd = open(fn, O_RDONLY)) < 0) {
1646 		serrno = errno;
1647 		DEBUGF("%s: %s\n", fn, strerror(serrno));
1648 		errno = serrno;
1649 	}
1650 	return (fd);
1651 }
1652 
1653 /*
1654  * Get authentication data for a URL from .netrc
1655  */
1656 int
1657 fetch_netrc_auth(struct url *url)
1658 {
1659 	const char *word;
1660 	int serrno;
1661 	FILE *f;
1662 
1663 	if (url->netrcfd < 0)
1664 		url->netrcfd = fetch_netrc_open();
1665 	if (url->netrcfd < 0)
1666 		return (-1);
1667 	if ((f = fdopen(url->netrcfd, "r")) == NULL) {
1668 		serrno = errno;
1669 		DEBUGF("fdopen(netrcfd): %s", strerror(errno));
1670 		close(url->netrcfd);
1671 		url->netrcfd = -1;
1672 		errno = serrno;
1673 		return (-1);
1674 	}
1675 	rewind(f);
1676 	DEBUGF("searching netrc for %s\n", url->host);
1677 	while ((word = fetch_read_word(f)) != NULL) {
1678 		if (strcmp(word, "default") == 0) {
1679 			DEBUGF("using default netrc settings\n");
1680 			break;
1681 		}
1682 		if (strcmp(word, "machine") == 0 &&
1683 		    (word = fetch_read_word(f)) != NULL &&
1684 		    strcasecmp(word, url->host) == 0) {
1685 			DEBUGF("using netrc settings for %s\n", word);
1686 			break;
1687 		}
1688 	}
1689 	if (word == NULL)
1690 		goto ferr;
1691 	while ((word = fetch_read_word(f)) != NULL) {
1692 		if (strcmp(word, "login") == 0) {
1693 			if ((word = fetch_read_word(f)) == NULL)
1694 				goto ferr;
1695 			if (snprintf(url->user, sizeof(url->user),
1696 				"%s", word) > (int)sizeof(url->user)) {
1697 				fetch_info("login name in .netrc is too long");
1698 				url->user[0] = '\0';
1699 			}
1700 		} else if (strcmp(word, "password") == 0) {
1701 			if ((word = fetch_read_word(f)) == NULL)
1702 				goto ferr;
1703 			if (snprintf(url->pwd, sizeof(url->pwd),
1704 				"%s", word) > (int)sizeof(url->pwd)) {
1705 				fetch_info("password in .netrc is too long");
1706 				url->pwd[0] = '\0';
1707 			}
1708 		} else if (strcmp(word, "account") == 0) {
1709 			if ((word = fetch_read_word(f)) == NULL)
1710 				goto ferr;
1711 			/* XXX not supported! */
1712 		} else {
1713 			break;
1714 		}
1715 	}
1716 	fclose(f);
1717 	url->netrcfd = -1;
1718 	return (0);
1719 ferr:
1720 	serrno = errno;
1721 	fclose(f);
1722 	url->netrcfd = -1;
1723 	errno = serrno;
1724 	return (-1);
1725 }
1726 
1727 /*
1728  * The no_proxy environment variable specifies a set of domains for
1729  * which the proxy should not be consulted; the contents is a comma-,
1730  * or space-separated list of domain names.  A single asterisk will
1731  * override all proxy variables and no transactions will be proxied
1732  * (for compatibility with lynx and curl, see the discussion at
1733  * <http://curl.haxx.se/mail/archive_pre_oct_99/0009.html>).
1734  */
1735 int
1736 fetch_no_proxy_match(const char *host)
1737 {
1738 	const char *no_proxy, *p, *q;
1739 	size_t h_len, d_len;
1740 
1741 	if ((no_proxy = getenv("NO_PROXY")) == NULL &&
1742 	    (no_proxy = getenv("no_proxy")) == NULL)
1743 		return (0);
1744 
1745 	/* asterisk matches any hostname */
1746 	if (strcmp(no_proxy, "*") == 0)
1747 		return (1);
1748 
1749 	h_len = strlen(host);
1750 	p = no_proxy;
1751 	do {
1752 		/* position p at the beginning of a domain suffix */
1753 		while (*p == ',' || isspace((unsigned char)*p))
1754 			p++;
1755 
1756 		/* position q at the first separator character */
1757 		for (q = p; *q; ++q)
1758 			if (*q == ',' || isspace((unsigned char)*q))
1759 				break;
1760 
1761 		d_len = q - p;
1762 		if (d_len > 0 && h_len >= d_len &&
1763 		    strncasecmp(host + h_len - d_len,
1764 			p, d_len) == 0) {
1765 			/* domain name matches */
1766 			return (1);
1767 		}
1768 
1769 		p = q + 1;
1770 	} while (*q);
1771 
1772 	return (0);
1773 }
1774