xref: /openbsd-src/usr.bin/ssh/misc.c (revision 24bb5fcea3ed904bc467217bdaadb5dfc618d5bf)
1 /* $OpenBSD: misc.c,v 1.168 2021/07/12 06:22:57 dtucker Exp $ */
2 /*
3  * Copyright (c) 2000 Markus Friedl.  All rights reserved.
4  * Copyright (c) 2005-2020 Damien Miller.  All rights reserved.
5  * Copyright (c) 2004 Henning Brauer <henning@openbsd.org>
6  *
7  * Permission to use, copy, modify, and distribute this software for any
8  * purpose with or without fee is hereby granted, provided that the above
9  * copyright notice and this permission notice appear in all copies.
10  *
11  * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
12  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
13  * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
14  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
15  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
16  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
17  * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
18  */
19 
20 
21 #include <sys/types.h>
22 #include <sys/ioctl.h>
23 #include <sys/socket.h>
24 #include <sys/stat.h>
25 #include <sys/time.h>
26 #include <sys/wait.h>
27 #include <sys/un.h>
28 
29 #include <net/if.h>
30 #include <netinet/in.h>
31 #include <netinet/ip.h>
32 #include <netinet/tcp.h>
33 #include <arpa/inet.h>
34 
35 #include <ctype.h>
36 #include <errno.h>
37 #include <fcntl.h>
38 #include <netdb.h>
39 #include <paths.h>
40 #include <pwd.h>
41 #include <libgen.h>
42 #include <limits.h>
43 #include <poll.h>
44 #include <signal.h>
45 #include <stdarg.h>
46 #include <stdio.h>
47 #include <stdlib.h>
48 #include <string.h>
49 #include <unistd.h>
50 
51 #include "xmalloc.h"
52 #include "misc.h"
53 #include "log.h"
54 #include "ssh.h"
55 #include "sshbuf.h"
56 #include "ssherr.h"
57 
58 /* remove newline at end of string */
59 char *
60 chop(char *s)
61 {
62 	char *t = s;
63 	while (*t) {
64 		if (*t == '\n' || *t == '\r') {
65 			*t = '\0';
66 			return s;
67 		}
68 		t++;
69 	}
70 	return s;
71 
72 }
73 
74 /* remove whitespace from end of string */
75 void
76 rtrim(char *s)
77 {
78 	size_t i;
79 
80 	if ((i = strlen(s)) == 0)
81 		return;
82 	for (i--; i > 0; i--) {
83 		if (isspace((int)s[i]))
84 			s[i] = '\0';
85 	}
86 }
87 
88 /* set/unset filedescriptor to non-blocking */
89 int
90 set_nonblock(int fd)
91 {
92 	int val;
93 
94 	val = fcntl(fd, F_GETFL);
95 	if (val == -1) {
96 		error("fcntl(%d, F_GETFL): %s", fd, strerror(errno));
97 		return (-1);
98 	}
99 	if (val & O_NONBLOCK) {
100 		debug3("fd %d is O_NONBLOCK", fd);
101 		return (0);
102 	}
103 	debug2("fd %d setting O_NONBLOCK", fd);
104 	val |= O_NONBLOCK;
105 	if (fcntl(fd, F_SETFL, val) == -1) {
106 		debug("fcntl(%d, F_SETFL, O_NONBLOCK): %s", fd,
107 		    strerror(errno));
108 		return (-1);
109 	}
110 	return (0);
111 }
112 
113 int
114 unset_nonblock(int fd)
115 {
116 	int val;
117 
118 	val = fcntl(fd, F_GETFL);
119 	if (val == -1) {
120 		error("fcntl(%d, F_GETFL): %s", fd, strerror(errno));
121 		return (-1);
122 	}
123 	if (!(val & O_NONBLOCK)) {
124 		debug3("fd %d is not O_NONBLOCK", fd);
125 		return (0);
126 	}
127 	debug("fd %d clearing O_NONBLOCK", fd);
128 	val &= ~O_NONBLOCK;
129 	if (fcntl(fd, F_SETFL, val) == -1) {
130 		debug("fcntl(%d, F_SETFL, ~O_NONBLOCK): %s",
131 		    fd, strerror(errno));
132 		return (-1);
133 	}
134 	return (0);
135 }
136 
137 const char *
138 ssh_gai_strerror(int gaierr)
139 {
140 	if (gaierr == EAI_SYSTEM && errno != 0)
141 		return strerror(errno);
142 	return gai_strerror(gaierr);
143 }
144 
145 /* disable nagle on socket */
146 void
147 set_nodelay(int fd)
148 {
149 	int opt;
150 	socklen_t optlen;
151 
152 	optlen = sizeof opt;
153 	if (getsockopt(fd, IPPROTO_TCP, TCP_NODELAY, &opt, &optlen) == -1) {
154 		debug("getsockopt TCP_NODELAY: %.100s", strerror(errno));
155 		return;
156 	}
157 	if (opt == 1) {
158 		debug2("fd %d is TCP_NODELAY", fd);
159 		return;
160 	}
161 	opt = 1;
162 	debug2("fd %d setting TCP_NODELAY", fd);
163 	if (setsockopt(fd, IPPROTO_TCP, TCP_NODELAY, &opt, sizeof opt) == -1)
164 		error("setsockopt TCP_NODELAY: %.100s", strerror(errno));
165 }
166 
167 /* Allow local port reuse in TIME_WAIT */
168 int
169 set_reuseaddr(int fd)
170 {
171 	int on = 1;
172 
173 	if (setsockopt(fd, SOL_SOCKET, SO_REUSEADDR, &on, sizeof(on)) == -1) {
174 		error("setsockopt SO_REUSEADDR fd %d: %s", fd, strerror(errno));
175 		return -1;
176 	}
177 	return 0;
178 }
179 
180 /* Get/set routing domain */
181 char *
182 get_rdomain(int fd)
183 {
184 	int rtable;
185 	char *ret;
186 	socklen_t len = sizeof(rtable);
187 
188 	if (getsockopt(fd, SOL_SOCKET, SO_RTABLE, &rtable, &len) == -1) {
189 		error("Failed to get routing domain for fd %d: %s",
190 		    fd, strerror(errno));
191 		return NULL;
192 	}
193 	xasprintf(&ret, "%d", rtable);
194 	return ret;
195 }
196 
197 int
198 set_rdomain(int fd, const char *name)
199 {
200 	int rtable;
201 	const char *errstr;
202 
203 	if (name == NULL)
204 		return 0; /* default table */
205 
206 	rtable = (int)strtonum(name, 0, 255, &errstr);
207 	if (errstr != NULL) {
208 		/* Shouldn't happen */
209 		error("Invalid routing domain \"%s\": %s", name, errstr);
210 		return -1;
211 	}
212 	if (setsockopt(fd, SOL_SOCKET, SO_RTABLE,
213 	    &rtable, sizeof(rtable)) == -1) {
214 		error("Failed to set routing domain %d on fd %d: %s",
215 		    rtable, fd, strerror(errno));
216 		return -1;
217 	}
218 	return 0;
219 }
220 
221 int
222 get_sock_af(int fd)
223 {
224 	struct sockaddr_storage to;
225 	socklen_t tolen = sizeof(to);
226 
227 	memset(&to, 0, sizeof(to));
228 	if (getsockname(fd, (struct sockaddr *)&to, &tolen) == -1)
229 		return -1;
230 	return to.ss_family;
231 }
232 
233 void
234 set_sock_tos(int fd, int tos)
235 {
236 	int af;
237 
238 	switch ((af = get_sock_af(fd))) {
239 	case -1:
240 		/* assume not a socket */
241 		break;
242 	case AF_INET:
243 		debug3_f("set socket %d IP_TOS 0x%02x", fd, tos);
244 		if (setsockopt(fd, IPPROTO_IP, IP_TOS,
245 		    &tos, sizeof(tos)) == -1) {
246 			error("setsockopt socket %d IP_TOS %d: %s:",
247 			    fd, tos, strerror(errno));
248 		}
249 		break;
250 	case AF_INET6:
251 		debug3_f("set socket %d IPV6_TCLASS 0x%02x", fd, tos);
252 		if (setsockopt(fd, IPPROTO_IPV6, IPV6_TCLASS,
253 		    &tos, sizeof(tos)) == -1) {
254 			error("setsockopt socket %d IPV6_TCLASS %d: %.100s:",
255 			    fd, tos, strerror(errno));
256 		}
257 		break;
258 	default:
259 		debug2_f("unsupported socket family %d", af);
260 		break;
261 	}
262 }
263 
264 /*
265  * Wait up to *timeoutp milliseconds for events on fd. Updates
266  * *timeoutp with time remaining.
267  * Returns 0 if fd ready or -1 on timeout or error (see errno).
268  */
269 static int
270 waitfd(int fd, int *timeoutp, short events)
271 {
272 	struct pollfd pfd;
273 	struct timeval t_start;
274 	int oerrno, r;
275 
276 	pfd.fd = fd;
277 	pfd.events = events;
278 	for (; *timeoutp >= 0;) {
279 		monotime_tv(&t_start);
280 		r = poll(&pfd, 1, *timeoutp);
281 		oerrno = errno;
282 		ms_subtract_diff(&t_start, timeoutp);
283 		errno = oerrno;
284 		if (r > 0)
285 			return 0;
286 		else if (r == -1 && errno != EAGAIN && errno != EINTR)
287 			return -1;
288 		else if (r == 0)
289 			break;
290 	}
291 	/* timeout */
292 	errno = ETIMEDOUT;
293 	return -1;
294 }
295 
296 /*
297  * Wait up to *timeoutp milliseconds for fd to be readable. Updates
298  * *timeoutp with time remaining.
299  * Returns 0 if fd ready or -1 on timeout or error (see errno).
300  */
301 int
302 waitrfd(int fd, int *timeoutp) {
303 	return waitfd(fd, timeoutp, POLLIN);
304 }
305 
306 /*
307  * Attempt a non-blocking connect(2) to the specified address, waiting up to
308  * *timeoutp milliseconds for the connection to complete. If the timeout is
309  * <=0, then wait indefinitely.
310  *
311  * Returns 0 on success or -1 on failure.
312  */
313 int
314 timeout_connect(int sockfd, const struct sockaddr *serv_addr,
315     socklen_t addrlen, int *timeoutp)
316 {
317 	int optval = 0;
318 	socklen_t optlen = sizeof(optval);
319 
320 	/* No timeout: just do a blocking connect() */
321 	if (timeoutp == NULL || *timeoutp <= 0)
322 		return connect(sockfd, serv_addr, addrlen);
323 
324 	set_nonblock(sockfd);
325 	for (;;) {
326 		if (connect(sockfd, serv_addr, addrlen) == 0) {
327 			/* Succeeded already? */
328 			unset_nonblock(sockfd);
329 			return 0;
330 		} else if (errno == EINTR)
331 			continue;
332 		else if (errno != EINPROGRESS)
333 			return -1;
334 		break;
335 	}
336 
337 	if (waitfd(sockfd, timeoutp, POLLIN | POLLOUT) == -1)
338 		return -1;
339 
340 	/* Completed or failed */
341 	if (getsockopt(sockfd, SOL_SOCKET, SO_ERROR, &optval, &optlen) == -1) {
342 		debug("getsockopt: %s", strerror(errno));
343 		return -1;
344 	}
345 	if (optval != 0) {
346 		errno = optval;
347 		return -1;
348 	}
349 	unset_nonblock(sockfd);
350 	return 0;
351 }
352 
353 /* Characters considered whitespace in strsep calls. */
354 #define WHITESPACE " \t\r\n"
355 #define QUOTE	"\""
356 
357 /* return next token in configuration line */
358 static char *
359 strdelim_internal(char **s, int split_equals)
360 {
361 	char *old;
362 	int wspace = 0;
363 
364 	if (*s == NULL)
365 		return NULL;
366 
367 	old = *s;
368 
369 	*s = strpbrk(*s,
370 	    split_equals ? WHITESPACE QUOTE "=" : WHITESPACE QUOTE);
371 	if (*s == NULL)
372 		return (old);
373 
374 	if (*s[0] == '\"') {
375 		memmove(*s, *s + 1, strlen(*s)); /* move nul too */
376 		/* Find matching quote */
377 		if ((*s = strpbrk(*s, QUOTE)) == NULL) {
378 			return (NULL);		/* no matching quote */
379 		} else {
380 			*s[0] = '\0';
381 			*s += strspn(*s + 1, WHITESPACE) + 1;
382 			return (old);
383 		}
384 	}
385 
386 	/* Allow only one '=' to be skipped */
387 	if (split_equals && *s[0] == '=')
388 		wspace = 1;
389 	*s[0] = '\0';
390 
391 	/* Skip any extra whitespace after first token */
392 	*s += strspn(*s + 1, WHITESPACE) + 1;
393 	if (split_equals && *s[0] == '=' && !wspace)
394 		*s += strspn(*s + 1, WHITESPACE) + 1;
395 
396 	return (old);
397 }
398 
399 /*
400  * Return next token in configuration line; splts on whitespace or a
401  * single '=' character.
402  */
403 char *
404 strdelim(char **s)
405 {
406 	return strdelim_internal(s, 1);
407 }
408 
409 /*
410  * Return next token in configuration line; splts on whitespace only.
411  */
412 char *
413 strdelimw(char **s)
414 {
415 	return strdelim_internal(s, 0);
416 }
417 
418 struct passwd *
419 pwcopy(struct passwd *pw)
420 {
421 	struct passwd *copy = xcalloc(1, sizeof(*copy));
422 
423 	copy->pw_name = xstrdup(pw->pw_name);
424 	copy->pw_passwd = xstrdup(pw->pw_passwd);
425 	copy->pw_gecos = xstrdup(pw->pw_gecos);
426 	copy->pw_uid = pw->pw_uid;
427 	copy->pw_gid = pw->pw_gid;
428 	copy->pw_expire = pw->pw_expire;
429 	copy->pw_change = pw->pw_change;
430 	copy->pw_class = xstrdup(pw->pw_class);
431 	copy->pw_dir = xstrdup(pw->pw_dir);
432 	copy->pw_shell = xstrdup(pw->pw_shell);
433 	return copy;
434 }
435 
436 /*
437  * Convert ASCII string to TCP/IP port number.
438  * Port must be >=0 and <=65535.
439  * Return -1 if invalid.
440  */
441 int
442 a2port(const char *s)
443 {
444 	struct servent *se;
445 	long long port;
446 	const char *errstr;
447 
448 	port = strtonum(s, 0, 65535, &errstr);
449 	if (errstr == NULL)
450 		return (int)port;
451 	if ((se = getservbyname(s, "tcp")) != NULL)
452 		return ntohs(se->s_port);
453 	return -1;
454 }
455 
456 int
457 a2tun(const char *s, int *remote)
458 {
459 	const char *errstr = NULL;
460 	char *sp, *ep;
461 	int tun;
462 
463 	if (remote != NULL) {
464 		*remote = SSH_TUNID_ANY;
465 		sp = xstrdup(s);
466 		if ((ep = strchr(sp, ':')) == NULL) {
467 			free(sp);
468 			return (a2tun(s, NULL));
469 		}
470 		ep[0] = '\0'; ep++;
471 		*remote = a2tun(ep, NULL);
472 		tun = a2tun(sp, NULL);
473 		free(sp);
474 		return (*remote == SSH_TUNID_ERR ? *remote : tun);
475 	}
476 
477 	if (strcasecmp(s, "any") == 0)
478 		return (SSH_TUNID_ANY);
479 
480 	tun = strtonum(s, 0, SSH_TUNID_MAX, &errstr);
481 	if (errstr != NULL)
482 		return (SSH_TUNID_ERR);
483 
484 	return (tun);
485 }
486 
487 #define SECONDS		1
488 #define MINUTES		(SECONDS * 60)
489 #define HOURS		(MINUTES * 60)
490 #define DAYS		(HOURS * 24)
491 #define WEEKS		(DAYS * 7)
492 
493 /*
494  * Convert a time string into seconds; format is
495  * a sequence of:
496  *      time[qualifier]
497  *
498  * Valid time qualifiers are:
499  *      <none>  seconds
500  *      s|S     seconds
501  *      m|M     minutes
502  *      h|H     hours
503  *      d|D     days
504  *      w|W     weeks
505  *
506  * Examples:
507  *      90m     90 minutes
508  *      1h30m   90 minutes
509  *      2d      2 days
510  *      1w      1 week
511  *
512  * Return -1 if time string is invalid.
513  */
514 int
515 convtime(const char *s)
516 {
517 	long total, secs, multiplier;
518 	const char *p;
519 	char *endp;
520 
521 	errno = 0;
522 	total = 0;
523 	p = s;
524 
525 	if (p == NULL || *p == '\0')
526 		return -1;
527 
528 	while (*p) {
529 		secs = strtol(p, &endp, 10);
530 		if (p == endp ||
531 		    (errno == ERANGE && (secs == INT_MIN || secs == INT_MAX)) ||
532 		    secs < 0)
533 			return -1;
534 
535 		multiplier = 1;
536 		switch (*endp++) {
537 		case '\0':
538 			endp--;
539 			break;
540 		case 's':
541 		case 'S':
542 			break;
543 		case 'm':
544 		case 'M':
545 			multiplier = MINUTES;
546 			break;
547 		case 'h':
548 		case 'H':
549 			multiplier = HOURS;
550 			break;
551 		case 'd':
552 		case 'D':
553 			multiplier = DAYS;
554 			break;
555 		case 'w':
556 		case 'W':
557 			multiplier = WEEKS;
558 			break;
559 		default:
560 			return -1;
561 		}
562 		if (secs > INT_MAX / multiplier)
563 			return -1;
564 		secs *= multiplier;
565 		if  (total > INT_MAX - secs)
566 			return -1;
567 		total += secs;
568 		if (total < 0)
569 			return -1;
570 		p = endp;
571 	}
572 
573 	return total;
574 }
575 
576 #define TF_BUFS	8
577 #define TF_LEN	9
578 
579 const char *
580 fmt_timeframe(time_t t)
581 {
582 	char		*buf;
583 	static char	 tfbuf[TF_BUFS][TF_LEN];	/* ring buffer */
584 	static int	 idx = 0;
585 	unsigned int	 sec, min, hrs, day;
586 	unsigned long long	week;
587 
588 	buf = tfbuf[idx++];
589 	if (idx == TF_BUFS)
590 		idx = 0;
591 
592 	week = t;
593 
594 	sec = week % 60;
595 	week /= 60;
596 	min = week % 60;
597 	week /= 60;
598 	hrs = week % 24;
599 	week /= 24;
600 	day = week % 7;
601 	week /= 7;
602 
603 	if (week > 0)
604 		snprintf(buf, TF_LEN, "%02lluw%01ud%02uh", week, day, hrs);
605 	else if (day > 0)
606 		snprintf(buf, TF_LEN, "%01ud%02uh%02um", day, hrs, min);
607 	else
608 		snprintf(buf, TF_LEN, "%02u:%02u:%02u", hrs, min, sec);
609 
610 	return (buf);
611 }
612 
613 /*
614  * Returns a standardized host+port identifier string.
615  * Caller must free returned string.
616  */
617 char *
618 put_host_port(const char *host, u_short port)
619 {
620 	char *hoststr;
621 
622 	if (port == 0 || port == SSH_DEFAULT_PORT)
623 		return(xstrdup(host));
624 	if (asprintf(&hoststr, "[%s]:%d", host, (int)port) == -1)
625 		fatal("put_host_port: asprintf: %s", strerror(errno));
626 	debug3("put_host_port: %s", hoststr);
627 	return hoststr;
628 }
629 
630 /*
631  * Search for next delimiter between hostnames/addresses and ports.
632  * Argument may be modified (for termination).
633  * Returns *cp if parsing succeeds.
634  * *cp is set to the start of the next field, if one was found.
635  * The delimiter char, if present, is stored in delim.
636  * If this is the last field, *cp is set to NULL.
637  */
638 char *
639 hpdelim2(char **cp, char *delim)
640 {
641 	char *s, *old;
642 
643 	if (cp == NULL || *cp == NULL)
644 		return NULL;
645 
646 	old = s = *cp;
647 	if (*s == '[') {
648 		if ((s = strchr(s, ']')) == NULL)
649 			return NULL;
650 		else
651 			s++;
652 	} else if ((s = strpbrk(s, ":/")) == NULL)
653 		s = *cp + strlen(*cp); /* skip to end (see first case below) */
654 
655 	switch (*s) {
656 	case '\0':
657 		*cp = NULL;	/* no more fields*/
658 		break;
659 
660 	case ':':
661 	case '/':
662 		if (delim != NULL)
663 			*delim = *s;
664 		*s = '\0';	/* terminate */
665 		*cp = s + 1;
666 		break;
667 
668 	default:
669 		return NULL;
670 	}
671 
672 	return old;
673 }
674 
675 char *
676 hpdelim(char **cp)
677 {
678 	return hpdelim2(cp, NULL);
679 }
680 
681 char *
682 cleanhostname(char *host)
683 {
684 	if (*host == '[' && host[strlen(host) - 1] == ']') {
685 		host[strlen(host) - 1] = '\0';
686 		return (host + 1);
687 	} else
688 		return host;
689 }
690 
691 char *
692 colon(char *cp)
693 {
694 	int flag = 0;
695 
696 	if (*cp == ':')		/* Leading colon is part of file name. */
697 		return NULL;
698 	if (*cp == '[')
699 		flag = 1;
700 
701 	for (; *cp; ++cp) {
702 		if (*cp == '@' && *(cp+1) == '[')
703 			flag = 1;
704 		if (*cp == ']' && *(cp+1) == ':' && flag)
705 			return (cp+1);
706 		if (*cp == ':' && !flag)
707 			return (cp);
708 		if (*cp == '/')
709 			return NULL;
710 	}
711 	return NULL;
712 }
713 
714 /*
715  * Parse a [user@]host:[path] string.
716  * Caller must free returned user, host and path.
717  * Any of the pointer return arguments may be NULL (useful for syntax checking).
718  * If user was not specified then *userp will be set to NULL.
719  * If host was not specified then *hostp will be set to NULL.
720  * If path was not specified then *pathp will be set to ".".
721  * Returns 0 on success, -1 on failure.
722  */
723 int
724 parse_user_host_path(const char *s, char **userp, char **hostp, char **pathp)
725 {
726 	char *user = NULL, *host = NULL, *path = NULL;
727 	char *sdup, *tmp;
728 	int ret = -1;
729 
730 	if (userp != NULL)
731 		*userp = NULL;
732 	if (hostp != NULL)
733 		*hostp = NULL;
734 	if (pathp != NULL)
735 		*pathp = NULL;
736 
737 	sdup = xstrdup(s);
738 
739 	/* Check for remote syntax: [user@]host:[path] */
740 	if ((tmp = colon(sdup)) == NULL)
741 		goto out;
742 
743 	/* Extract optional path */
744 	*tmp++ = '\0';
745 	if (*tmp == '\0')
746 		tmp = ".";
747 	path = xstrdup(tmp);
748 
749 	/* Extract optional user and mandatory host */
750 	tmp = strrchr(sdup, '@');
751 	if (tmp != NULL) {
752 		*tmp++ = '\0';
753 		host = xstrdup(cleanhostname(tmp));
754 		if (*sdup != '\0')
755 			user = xstrdup(sdup);
756 	} else {
757 		host = xstrdup(cleanhostname(sdup));
758 		user = NULL;
759 	}
760 
761 	/* Success */
762 	if (userp != NULL) {
763 		*userp = user;
764 		user = NULL;
765 	}
766 	if (hostp != NULL) {
767 		*hostp = host;
768 		host = NULL;
769 	}
770 	if (pathp != NULL) {
771 		*pathp = path;
772 		path = NULL;
773 	}
774 	ret = 0;
775 out:
776 	free(sdup);
777 	free(user);
778 	free(host);
779 	free(path);
780 	return ret;
781 }
782 
783 /*
784  * Parse a [user@]host[:port] string.
785  * Caller must free returned user and host.
786  * Any of the pointer return arguments may be NULL (useful for syntax checking).
787  * If user was not specified then *userp will be set to NULL.
788  * If port was not specified then *portp will be -1.
789  * Returns 0 on success, -1 on failure.
790  */
791 int
792 parse_user_host_port(const char *s, char **userp, char **hostp, int *portp)
793 {
794 	char *sdup, *cp, *tmp;
795 	char *user = NULL, *host = NULL;
796 	int port = -1, ret = -1;
797 
798 	if (userp != NULL)
799 		*userp = NULL;
800 	if (hostp != NULL)
801 		*hostp = NULL;
802 	if (portp != NULL)
803 		*portp = -1;
804 
805 	if ((sdup = tmp = strdup(s)) == NULL)
806 		return -1;
807 	/* Extract optional username */
808 	if ((cp = strrchr(tmp, '@')) != NULL) {
809 		*cp = '\0';
810 		if (*tmp == '\0')
811 			goto out;
812 		if ((user = strdup(tmp)) == NULL)
813 			goto out;
814 		tmp = cp + 1;
815 	}
816 	/* Extract mandatory hostname */
817 	if ((cp = hpdelim(&tmp)) == NULL || *cp == '\0')
818 		goto out;
819 	host = xstrdup(cleanhostname(cp));
820 	/* Convert and verify optional port */
821 	if (tmp != NULL && *tmp != '\0') {
822 		if ((port = a2port(tmp)) <= 0)
823 			goto out;
824 	}
825 	/* Success */
826 	if (userp != NULL) {
827 		*userp = user;
828 		user = NULL;
829 	}
830 	if (hostp != NULL) {
831 		*hostp = host;
832 		host = NULL;
833 	}
834 	if (portp != NULL)
835 		*portp = port;
836 	ret = 0;
837  out:
838 	free(sdup);
839 	free(user);
840 	free(host);
841 	return ret;
842 }
843 
844 /*
845  * Converts a two-byte hex string to decimal.
846  * Returns the decimal value or -1 for invalid input.
847  */
848 static int
849 hexchar(const char *s)
850 {
851 	unsigned char result[2];
852 	int i;
853 
854 	for (i = 0; i < 2; i++) {
855 		if (s[i] >= '0' && s[i] <= '9')
856 			result[i] = (unsigned char)(s[i] - '0');
857 		else if (s[i] >= 'a' && s[i] <= 'f')
858 			result[i] = (unsigned char)(s[i] - 'a') + 10;
859 		else if (s[i] >= 'A' && s[i] <= 'F')
860 			result[i] = (unsigned char)(s[i] - 'A') + 10;
861 		else
862 			return -1;
863 	}
864 	return (result[0] << 4) | result[1];
865 }
866 
867 /*
868  * Decode an url-encoded string.
869  * Returns a newly allocated string on success or NULL on failure.
870  */
871 static char *
872 urldecode(const char *src)
873 {
874 	char *ret, *dst;
875 	int ch;
876 
877 	ret = xmalloc(strlen(src) + 1);
878 	for (dst = ret; *src != '\0'; src++) {
879 		switch (*src) {
880 		case '+':
881 			*dst++ = ' ';
882 			break;
883 		case '%':
884 			if (!isxdigit((unsigned char)src[1]) ||
885 			    !isxdigit((unsigned char)src[2]) ||
886 			    (ch = hexchar(src + 1)) == -1) {
887 				free(ret);
888 				return NULL;
889 			}
890 			*dst++ = ch;
891 			src += 2;
892 			break;
893 		default:
894 			*dst++ = *src;
895 			break;
896 		}
897 	}
898 	*dst = '\0';
899 
900 	return ret;
901 }
902 
903 /*
904  * Parse an (scp|ssh|sftp)://[user@]host[:port][/path] URI.
905  * See https://tools.ietf.org/html/draft-ietf-secsh-scp-sftp-ssh-uri-04
906  * Either user or path may be url-encoded (but not host or port).
907  * Caller must free returned user, host and path.
908  * Any of the pointer return arguments may be NULL (useful for syntax checking)
909  * but the scheme must always be specified.
910  * If user was not specified then *userp will be set to NULL.
911  * If port was not specified then *portp will be -1.
912  * If path was not specified then *pathp will be set to NULL.
913  * Returns 0 on success, 1 if non-uri/wrong scheme, -1 on error/invalid uri.
914  */
915 int
916 parse_uri(const char *scheme, const char *uri, char **userp, char **hostp,
917     int *portp, char **pathp)
918 {
919 	char *uridup, *cp, *tmp, ch;
920 	char *user = NULL, *host = NULL, *path = NULL;
921 	int port = -1, ret = -1;
922 	size_t len;
923 
924 	len = strlen(scheme);
925 	if (strncmp(uri, scheme, len) != 0 || strncmp(uri + len, "://", 3) != 0)
926 		return 1;
927 	uri += len + 3;
928 
929 	if (userp != NULL)
930 		*userp = NULL;
931 	if (hostp != NULL)
932 		*hostp = NULL;
933 	if (portp != NULL)
934 		*portp = -1;
935 	if (pathp != NULL)
936 		*pathp = NULL;
937 
938 	uridup = tmp = xstrdup(uri);
939 
940 	/* Extract optional ssh-info (username + connection params) */
941 	if ((cp = strchr(tmp, '@')) != NULL) {
942 		char *delim;
943 
944 		*cp = '\0';
945 		/* Extract username and connection params */
946 		if ((delim = strchr(tmp, ';')) != NULL) {
947 			/* Just ignore connection params for now */
948 			*delim = '\0';
949 		}
950 		if (*tmp == '\0') {
951 			/* Empty username */
952 			goto out;
953 		}
954 		if ((user = urldecode(tmp)) == NULL)
955 			goto out;
956 		tmp = cp + 1;
957 	}
958 
959 	/* Extract mandatory hostname */
960 	if ((cp = hpdelim2(&tmp, &ch)) == NULL || *cp == '\0')
961 		goto out;
962 	host = xstrdup(cleanhostname(cp));
963 	if (!valid_domain(host, 0, NULL))
964 		goto out;
965 
966 	if (tmp != NULL && *tmp != '\0') {
967 		if (ch == ':') {
968 			/* Convert and verify port. */
969 			if ((cp = strchr(tmp, '/')) != NULL)
970 				*cp = '\0';
971 			if ((port = a2port(tmp)) <= 0)
972 				goto out;
973 			tmp = cp ? cp + 1 : NULL;
974 		}
975 		if (tmp != NULL && *tmp != '\0') {
976 			/* Extract optional path */
977 			if ((path = urldecode(tmp)) == NULL)
978 				goto out;
979 		}
980 	}
981 
982 	/* Success */
983 	if (userp != NULL) {
984 		*userp = user;
985 		user = NULL;
986 	}
987 	if (hostp != NULL) {
988 		*hostp = host;
989 		host = NULL;
990 	}
991 	if (portp != NULL)
992 		*portp = port;
993 	if (pathp != NULL) {
994 		*pathp = path;
995 		path = NULL;
996 	}
997 	ret = 0;
998  out:
999 	free(uridup);
1000 	free(user);
1001 	free(host);
1002 	free(path);
1003 	return ret;
1004 }
1005 
1006 /* function to assist building execv() arguments */
1007 void
1008 addargs(arglist *args, char *fmt, ...)
1009 {
1010 	va_list ap;
1011 	char *cp;
1012 	u_int nalloc;
1013 	int r;
1014 
1015 	va_start(ap, fmt);
1016 	r = vasprintf(&cp, fmt, ap);
1017 	va_end(ap);
1018 	if (r == -1)
1019 		fatal("addargs: argument too long");
1020 
1021 	nalloc = args->nalloc;
1022 	if (args->list == NULL) {
1023 		nalloc = 32;
1024 		args->num = 0;
1025 	} else if (args->num+2 >= nalloc)
1026 		nalloc *= 2;
1027 
1028 	args->list = xrecallocarray(args->list, args->nalloc, nalloc, sizeof(char *));
1029 	args->nalloc = nalloc;
1030 	args->list[args->num++] = cp;
1031 	args->list[args->num] = NULL;
1032 }
1033 
1034 void
1035 replacearg(arglist *args, u_int which, char *fmt, ...)
1036 {
1037 	va_list ap;
1038 	char *cp;
1039 	int r;
1040 
1041 	va_start(ap, fmt);
1042 	r = vasprintf(&cp, fmt, ap);
1043 	va_end(ap);
1044 	if (r == -1)
1045 		fatal("replacearg: argument too long");
1046 
1047 	if (which >= args->num)
1048 		fatal("replacearg: tried to replace invalid arg %d >= %d",
1049 		    which, args->num);
1050 	free(args->list[which]);
1051 	args->list[which] = cp;
1052 }
1053 
1054 void
1055 freeargs(arglist *args)
1056 {
1057 	u_int i;
1058 
1059 	if (args->list != NULL) {
1060 		for (i = 0; i < args->num; i++)
1061 			free(args->list[i]);
1062 		free(args->list);
1063 		args->nalloc = args->num = 0;
1064 		args->list = NULL;
1065 	}
1066 }
1067 
1068 /*
1069  * Expands tildes in the file name.  Returns data allocated by xmalloc.
1070  * Warning: this calls getpw*.
1071  */
1072 char *
1073 tilde_expand_filename(const char *filename, uid_t uid)
1074 {
1075 	const char *path, *sep;
1076 	char user[128], *ret;
1077 	struct passwd *pw;
1078 	u_int len, slash;
1079 
1080 	if (*filename != '~')
1081 		return (xstrdup(filename));
1082 	filename++;
1083 
1084 	path = strchr(filename, '/');
1085 	if (path != NULL && path > filename) {		/* ~user/path */
1086 		slash = path - filename;
1087 		if (slash > sizeof(user) - 1)
1088 			fatal("tilde_expand_filename: ~username too long");
1089 		memcpy(user, filename, slash);
1090 		user[slash] = '\0';
1091 		if ((pw = getpwnam(user)) == NULL)
1092 			fatal("tilde_expand_filename: No such user %s", user);
1093 	} else if ((pw = getpwuid(uid)) == NULL)	/* ~/path */
1094 		fatal("tilde_expand_filename: No such uid %ld", (long)uid);
1095 
1096 	/* Make sure directory has a trailing '/' */
1097 	len = strlen(pw->pw_dir);
1098 	if (len == 0 || pw->pw_dir[len - 1] != '/')
1099 		sep = "/";
1100 	else
1101 		sep = "";
1102 
1103 	/* Skip leading '/' from specified path */
1104 	if (path != NULL)
1105 		filename = path + 1;
1106 
1107 	if (xasprintf(&ret, "%s%s%s", pw->pw_dir, sep, filename) >= PATH_MAX)
1108 		fatal("tilde_expand_filename: Path too long");
1109 
1110 	return (ret);
1111 }
1112 
1113 /*
1114  * Expand a string with a set of %[char] escapes and/or ${ENVIRONMENT}
1115  * substitutions.  A number of escapes may be specified as
1116  * (char *escape_chars, char *replacement) pairs. The list must be terminated
1117  * by a NULL escape_char. Returns replaced string in memory allocated by
1118  * xmalloc which the caller must free.
1119  */
1120 static char *
1121 vdollar_percent_expand(int *parseerror, int dollar, int percent,
1122     const char *string, va_list ap)
1123 {
1124 #define EXPAND_MAX_KEYS	16
1125 	u_int num_keys = 0, i;
1126 	struct {
1127 		const char *key;
1128 		const char *repl;
1129 	} keys[EXPAND_MAX_KEYS];
1130 	struct sshbuf *buf;
1131 	int r, missingvar = 0;
1132 	char *ret = NULL, *var, *varend, *val;
1133 	size_t len;
1134 
1135 	if ((buf = sshbuf_new()) == NULL)
1136 		fatal_f("sshbuf_new failed");
1137 	if (parseerror == NULL)
1138 		fatal_f("null parseerror arg");
1139 	*parseerror = 1;
1140 
1141 	/* Gather keys if we're doing percent expansion. */
1142 	if (percent) {
1143 		for (num_keys = 0; num_keys < EXPAND_MAX_KEYS; num_keys++) {
1144 			keys[num_keys].key = va_arg(ap, char *);
1145 			if (keys[num_keys].key == NULL)
1146 				break;
1147 			keys[num_keys].repl = va_arg(ap, char *);
1148 			if (keys[num_keys].repl == NULL) {
1149 				fatal_f("NULL replacement for token %s",
1150 				    keys[num_keys].key);
1151 			}
1152 		}
1153 		if (num_keys == EXPAND_MAX_KEYS && va_arg(ap, char *) != NULL)
1154 			fatal_f("too many keys");
1155 		if (num_keys == 0)
1156 			fatal_f("percent expansion without token list");
1157 	}
1158 
1159 	/* Expand string */
1160 	for (i = 0; *string != '\0'; string++) {
1161 		/* Optionally process ${ENVIRONMENT} expansions. */
1162 		if (dollar && string[0] == '$' && string[1] == '{') {
1163 			string += 2;  /* skip over '${' */
1164 			if ((varend = strchr(string, '}')) == NULL) {
1165 				error_f("environment variable '%s' missing "
1166 				    "closing '}'", string);
1167 				goto out;
1168 			}
1169 			len = varend - string;
1170 			if (len == 0) {
1171 				error_f("zero-length environment variable");
1172 				goto out;
1173 			}
1174 			var = xmalloc(len + 1);
1175 			(void)strlcpy(var, string, len + 1);
1176 			if ((val = getenv(var)) == NULL) {
1177 				error_f("env var ${%s} has no value", var);
1178 				missingvar = 1;
1179 			} else {
1180 				debug3_f("expand ${%s} -> '%s'", var, val);
1181 				if ((r = sshbuf_put(buf, val, strlen(val))) !=0)
1182 					fatal_fr(r, "sshbuf_put ${}");
1183 			}
1184 			free(var);
1185 			string += len;
1186 			continue;
1187 		}
1188 
1189 		/*
1190 		 * Process percent expansions if we have a list of TOKENs.
1191 		 * If we're not doing percent expansion everything just gets
1192 		 * appended here.
1193 		 */
1194 		if (*string != '%' || !percent) {
1195  append:
1196 			if ((r = sshbuf_put_u8(buf, *string)) != 0)
1197 				fatal_fr(r, "sshbuf_put_u8 %%");
1198 			continue;
1199 		}
1200 		string++;
1201 		/* %% case */
1202 		if (*string == '%')
1203 			goto append;
1204 		if (*string == '\0') {
1205 			error_f("invalid format");
1206 			goto out;
1207 		}
1208 		for (i = 0; i < num_keys; i++) {
1209 			if (strchr(keys[i].key, *string) != NULL) {
1210 				if ((r = sshbuf_put(buf, keys[i].repl,
1211 				    strlen(keys[i].repl))) != 0)
1212 					fatal_fr(r, "sshbuf_put %%-repl");
1213 				break;
1214 			}
1215 		}
1216 		if (i >= num_keys) {
1217 			error_f("unknown key %%%c", *string);
1218 			goto out;
1219 		}
1220 	}
1221 	if (!missingvar && (ret = sshbuf_dup_string(buf)) == NULL)
1222 		fatal_f("sshbuf_dup_string failed");
1223 	*parseerror = 0;
1224  out:
1225 	sshbuf_free(buf);
1226 	return *parseerror ? NULL : ret;
1227 #undef EXPAND_MAX_KEYS
1228 }
1229 
1230 /*
1231  * Expand only environment variables.
1232  * Note that although this function is variadic like the other similar
1233  * functions, any such arguments will be unused.
1234  */
1235 
1236 char *
1237 dollar_expand(int *parseerr, const char *string, ...)
1238 {
1239 	char *ret;
1240 	int err;
1241 	va_list ap;
1242 
1243 	va_start(ap, string);
1244 	ret = vdollar_percent_expand(&err, 1, 0, string, ap);
1245 	va_end(ap);
1246 	if (parseerr != NULL)
1247 		*parseerr = err;
1248 	return ret;
1249 }
1250 
1251 /*
1252  * Returns expanded string or NULL if a specified environment variable is
1253  * not defined, or calls fatal if the string is invalid.
1254  */
1255 char *
1256 percent_expand(const char *string, ...)
1257 {
1258 	char *ret;
1259 	int err;
1260 	va_list ap;
1261 
1262 	va_start(ap, string);
1263 	ret = vdollar_percent_expand(&err, 0, 1, string, ap);
1264 	va_end(ap);
1265 	if (err)
1266 		fatal_f("failed");
1267 	return ret;
1268 }
1269 
1270 /*
1271  * Returns expanded string or NULL if a specified environment variable is
1272  * not defined, or calls fatal if the string is invalid.
1273  */
1274 char *
1275 percent_dollar_expand(const char *string, ...)
1276 {
1277 	char *ret;
1278 	int err;
1279 	va_list ap;
1280 
1281 	va_start(ap, string);
1282 	ret = vdollar_percent_expand(&err, 1, 1, string, ap);
1283 	va_end(ap);
1284 	if (err)
1285 		fatal_f("failed");
1286 	return ret;
1287 }
1288 
1289 int
1290 tun_open(int tun, int mode, char **ifname)
1291 {
1292 	struct ifreq ifr;
1293 	char name[100];
1294 	int fd = -1, sock;
1295 	const char *tunbase = "tun";
1296 
1297 	if (ifname != NULL)
1298 		*ifname = NULL;
1299 
1300 	if (mode == SSH_TUNMODE_ETHERNET)
1301 		tunbase = "tap";
1302 
1303 	/* Open the tunnel device */
1304 	if (tun <= SSH_TUNID_MAX) {
1305 		snprintf(name, sizeof(name), "/dev/%s%d", tunbase, tun);
1306 		fd = open(name, O_RDWR);
1307 	} else if (tun == SSH_TUNID_ANY) {
1308 		for (tun = 100; tun >= 0; tun--) {
1309 			snprintf(name, sizeof(name), "/dev/%s%d",
1310 			    tunbase, tun);
1311 			if ((fd = open(name, O_RDWR)) >= 0)
1312 				break;
1313 		}
1314 	} else {
1315 		debug_f("invalid tunnel %u", tun);
1316 		return -1;
1317 	}
1318 
1319 	if (fd == -1) {
1320 		debug_f("%s open: %s", name, strerror(errno));
1321 		return -1;
1322 	}
1323 
1324 	debug_f("%s mode %d fd %d", name, mode, fd);
1325 
1326 	/* Bring interface up if it is not already */
1327 	snprintf(ifr.ifr_name, sizeof(ifr.ifr_name), "%s%d", tunbase, tun);
1328 	if ((sock = socket(PF_UNIX, SOCK_STREAM, 0)) == -1)
1329 		goto failed;
1330 
1331 	if (ioctl(sock, SIOCGIFFLAGS, &ifr) == -1) {
1332 		debug_f("get interface %s flags: %s", ifr.ifr_name,
1333 		    strerror(errno));
1334 		goto failed;
1335 	}
1336 
1337 	if (!(ifr.ifr_flags & IFF_UP)) {
1338 		ifr.ifr_flags |= IFF_UP;
1339 		if (ioctl(sock, SIOCSIFFLAGS, &ifr) == -1) {
1340 			debug_f("activate interface %s: %s", ifr.ifr_name,
1341 			    strerror(errno));
1342 			goto failed;
1343 		}
1344 	}
1345 
1346 	if (ifname != NULL)
1347 		*ifname = xstrdup(ifr.ifr_name);
1348 
1349 	close(sock);
1350 	return fd;
1351 
1352  failed:
1353 	if (fd >= 0)
1354 		close(fd);
1355 	if (sock >= 0)
1356 		close(sock);
1357 	return -1;
1358 }
1359 
1360 void
1361 sanitise_stdfd(void)
1362 {
1363 	int nullfd, dupfd;
1364 
1365 	if ((nullfd = dupfd = open(_PATH_DEVNULL, O_RDWR)) == -1) {
1366 		fprintf(stderr, "Couldn't open /dev/null: %s\n",
1367 		    strerror(errno));
1368 		exit(1);
1369 	}
1370 	while (++dupfd <= STDERR_FILENO) {
1371 		/* Only populate closed fds. */
1372 		if (fcntl(dupfd, F_GETFL) == -1 && errno == EBADF) {
1373 			if (dup2(nullfd, dupfd) == -1) {
1374 				fprintf(stderr, "dup2: %s\n", strerror(errno));
1375 				exit(1);
1376 			}
1377 		}
1378 	}
1379 	if (nullfd > STDERR_FILENO)
1380 		close(nullfd);
1381 }
1382 
1383 char *
1384 tohex(const void *vp, size_t l)
1385 {
1386 	const u_char *p = (const u_char *)vp;
1387 	char b[3], *r;
1388 	size_t i, hl;
1389 
1390 	if (l > 65536)
1391 		return xstrdup("tohex: length > 65536");
1392 
1393 	hl = l * 2 + 1;
1394 	r = xcalloc(1, hl);
1395 	for (i = 0; i < l; i++) {
1396 		snprintf(b, sizeof(b), "%02x", p[i]);
1397 		strlcat(r, b, hl);
1398 	}
1399 	return (r);
1400 }
1401 
1402 /*
1403  * Extend string *sp by the specified format. If *sp is not NULL (or empty),
1404  * then the separator 'sep' will be prepended before the formatted arguments.
1405  * Extended strings are heap allocated.
1406  */
1407 void
1408 xextendf(char **sp, const char *sep, const char *fmt, ...)
1409 {
1410 	va_list ap;
1411 	char *tmp1, *tmp2;
1412 
1413 	va_start(ap, fmt);
1414 	xvasprintf(&tmp1, fmt, ap);
1415 	va_end(ap);
1416 
1417 	if (*sp == NULL || **sp == '\0') {
1418 		free(*sp);
1419 		*sp = tmp1;
1420 		return;
1421 	}
1422 	xasprintf(&tmp2, "%s%s%s", *sp, sep == NULL ? "" : sep, tmp1);
1423 	free(tmp1);
1424 	free(*sp);
1425 	*sp = tmp2;
1426 }
1427 
1428 
1429 u_int64_t
1430 get_u64(const void *vp)
1431 {
1432 	const u_char *p = (const u_char *)vp;
1433 	u_int64_t v;
1434 
1435 	v  = (u_int64_t)p[0] << 56;
1436 	v |= (u_int64_t)p[1] << 48;
1437 	v |= (u_int64_t)p[2] << 40;
1438 	v |= (u_int64_t)p[3] << 32;
1439 	v |= (u_int64_t)p[4] << 24;
1440 	v |= (u_int64_t)p[5] << 16;
1441 	v |= (u_int64_t)p[6] << 8;
1442 	v |= (u_int64_t)p[7];
1443 
1444 	return (v);
1445 }
1446 
1447 u_int32_t
1448 get_u32(const void *vp)
1449 {
1450 	const u_char *p = (const u_char *)vp;
1451 	u_int32_t v;
1452 
1453 	v  = (u_int32_t)p[0] << 24;
1454 	v |= (u_int32_t)p[1] << 16;
1455 	v |= (u_int32_t)p[2] << 8;
1456 	v |= (u_int32_t)p[3];
1457 
1458 	return (v);
1459 }
1460 
1461 u_int32_t
1462 get_u32_le(const void *vp)
1463 {
1464 	const u_char *p = (const u_char *)vp;
1465 	u_int32_t v;
1466 
1467 	v  = (u_int32_t)p[0];
1468 	v |= (u_int32_t)p[1] << 8;
1469 	v |= (u_int32_t)p[2] << 16;
1470 	v |= (u_int32_t)p[3] << 24;
1471 
1472 	return (v);
1473 }
1474 
1475 u_int16_t
1476 get_u16(const void *vp)
1477 {
1478 	const u_char *p = (const u_char *)vp;
1479 	u_int16_t v;
1480 
1481 	v  = (u_int16_t)p[0] << 8;
1482 	v |= (u_int16_t)p[1];
1483 
1484 	return (v);
1485 }
1486 
1487 void
1488 put_u64(void *vp, u_int64_t v)
1489 {
1490 	u_char *p = (u_char *)vp;
1491 
1492 	p[0] = (u_char)(v >> 56) & 0xff;
1493 	p[1] = (u_char)(v >> 48) & 0xff;
1494 	p[2] = (u_char)(v >> 40) & 0xff;
1495 	p[3] = (u_char)(v >> 32) & 0xff;
1496 	p[4] = (u_char)(v >> 24) & 0xff;
1497 	p[5] = (u_char)(v >> 16) & 0xff;
1498 	p[6] = (u_char)(v >> 8) & 0xff;
1499 	p[7] = (u_char)v & 0xff;
1500 }
1501 
1502 void
1503 put_u32(void *vp, u_int32_t v)
1504 {
1505 	u_char *p = (u_char *)vp;
1506 
1507 	p[0] = (u_char)(v >> 24) & 0xff;
1508 	p[1] = (u_char)(v >> 16) & 0xff;
1509 	p[2] = (u_char)(v >> 8) & 0xff;
1510 	p[3] = (u_char)v & 0xff;
1511 }
1512 
1513 void
1514 put_u32_le(void *vp, u_int32_t v)
1515 {
1516 	u_char *p = (u_char *)vp;
1517 
1518 	p[0] = (u_char)v & 0xff;
1519 	p[1] = (u_char)(v >> 8) & 0xff;
1520 	p[2] = (u_char)(v >> 16) & 0xff;
1521 	p[3] = (u_char)(v >> 24) & 0xff;
1522 }
1523 
1524 void
1525 put_u16(void *vp, u_int16_t v)
1526 {
1527 	u_char *p = (u_char *)vp;
1528 
1529 	p[0] = (u_char)(v >> 8) & 0xff;
1530 	p[1] = (u_char)v & 0xff;
1531 }
1532 
1533 void
1534 ms_subtract_diff(struct timeval *start, int *ms)
1535 {
1536 	struct timeval diff, finish;
1537 
1538 	monotime_tv(&finish);
1539 	timersub(&finish, start, &diff);
1540 	*ms -= (diff.tv_sec * 1000) + (diff.tv_usec / 1000);
1541 }
1542 
1543 void
1544 ms_to_timeval(struct timeval *tv, int ms)
1545 {
1546 	if (ms < 0)
1547 		ms = 0;
1548 	tv->tv_sec = ms / 1000;
1549 	tv->tv_usec = (ms % 1000) * 1000;
1550 }
1551 
1552 void
1553 monotime_ts(struct timespec *ts)
1554 {
1555 	if (clock_gettime(CLOCK_MONOTONIC, ts) != 0)
1556 		fatal("clock_gettime: %s", strerror(errno));
1557 }
1558 
1559 void
1560 monotime_tv(struct timeval *tv)
1561 {
1562 	struct timespec ts;
1563 
1564 	monotime_ts(&ts);
1565 	tv->tv_sec = ts.tv_sec;
1566 	tv->tv_usec = ts.tv_nsec / 1000;
1567 }
1568 
1569 time_t
1570 monotime(void)
1571 {
1572 	struct timespec ts;
1573 
1574 	monotime_ts(&ts);
1575 	return (ts.tv_sec);
1576 }
1577 
1578 double
1579 monotime_double(void)
1580 {
1581 	struct timespec ts;
1582 
1583 	monotime_ts(&ts);
1584 	return (double)ts.tv_sec + (double)ts.tv_nsec / 1000000000.0;
1585 }
1586 
1587 void
1588 bandwidth_limit_init(struct bwlimit *bw, u_int64_t kbps, size_t buflen)
1589 {
1590 	bw->buflen = buflen;
1591 	bw->rate = kbps;
1592 	bw->thresh = buflen;
1593 	bw->lamt = 0;
1594 	timerclear(&bw->bwstart);
1595 	timerclear(&bw->bwend);
1596 }
1597 
1598 /* Callback from read/write loop to insert bandwidth-limiting delays */
1599 void
1600 bandwidth_limit(struct bwlimit *bw, size_t read_len)
1601 {
1602 	u_int64_t waitlen;
1603 	struct timespec ts, rm;
1604 
1605 	bw->lamt += read_len;
1606 	if (!timerisset(&bw->bwstart)) {
1607 		monotime_tv(&bw->bwstart);
1608 		return;
1609 	}
1610 	if (bw->lamt < bw->thresh)
1611 		return;
1612 
1613 	monotime_tv(&bw->bwend);
1614 	timersub(&bw->bwend, &bw->bwstart, &bw->bwend);
1615 	if (!timerisset(&bw->bwend))
1616 		return;
1617 
1618 	bw->lamt *= 8;
1619 	waitlen = (double)1000000L * bw->lamt / bw->rate;
1620 
1621 	bw->bwstart.tv_sec = waitlen / 1000000L;
1622 	bw->bwstart.tv_usec = waitlen % 1000000L;
1623 
1624 	if (timercmp(&bw->bwstart, &bw->bwend, >)) {
1625 		timersub(&bw->bwstart, &bw->bwend, &bw->bwend);
1626 
1627 		/* Adjust the wait time */
1628 		if (bw->bwend.tv_sec) {
1629 			bw->thresh /= 2;
1630 			if (bw->thresh < bw->buflen / 4)
1631 				bw->thresh = bw->buflen / 4;
1632 		} else if (bw->bwend.tv_usec < 10000) {
1633 			bw->thresh *= 2;
1634 			if (bw->thresh > bw->buflen * 8)
1635 				bw->thresh = bw->buflen * 8;
1636 		}
1637 
1638 		TIMEVAL_TO_TIMESPEC(&bw->bwend, &ts);
1639 		while (nanosleep(&ts, &rm) == -1) {
1640 			if (errno != EINTR)
1641 				break;
1642 			ts = rm;
1643 		}
1644 	}
1645 
1646 	bw->lamt = 0;
1647 	monotime_tv(&bw->bwstart);
1648 }
1649 
1650 /* Make a template filename for mk[sd]temp() */
1651 void
1652 mktemp_proto(char *s, size_t len)
1653 {
1654 	const char *tmpdir;
1655 	int r;
1656 
1657 	if ((tmpdir = getenv("TMPDIR")) != NULL) {
1658 		r = snprintf(s, len, "%s/ssh-XXXXXXXXXXXX", tmpdir);
1659 		if (r > 0 && (size_t)r < len)
1660 			return;
1661 	}
1662 	r = snprintf(s, len, "/tmp/ssh-XXXXXXXXXXXX");
1663 	if (r < 0 || (size_t)r >= len)
1664 		fatal_f("template string too short");
1665 }
1666 
1667 static const struct {
1668 	const char *name;
1669 	int value;
1670 } ipqos[] = {
1671 	{ "none", INT_MAX },		/* can't use 0 here; that's CS0 */
1672 	{ "af11", IPTOS_DSCP_AF11 },
1673 	{ "af12", IPTOS_DSCP_AF12 },
1674 	{ "af13", IPTOS_DSCP_AF13 },
1675 	{ "af21", IPTOS_DSCP_AF21 },
1676 	{ "af22", IPTOS_DSCP_AF22 },
1677 	{ "af23", IPTOS_DSCP_AF23 },
1678 	{ "af31", IPTOS_DSCP_AF31 },
1679 	{ "af32", IPTOS_DSCP_AF32 },
1680 	{ "af33", IPTOS_DSCP_AF33 },
1681 	{ "af41", IPTOS_DSCP_AF41 },
1682 	{ "af42", IPTOS_DSCP_AF42 },
1683 	{ "af43", IPTOS_DSCP_AF43 },
1684 	{ "cs0", IPTOS_DSCP_CS0 },
1685 	{ "cs1", IPTOS_DSCP_CS1 },
1686 	{ "cs2", IPTOS_DSCP_CS2 },
1687 	{ "cs3", IPTOS_DSCP_CS3 },
1688 	{ "cs4", IPTOS_DSCP_CS4 },
1689 	{ "cs5", IPTOS_DSCP_CS5 },
1690 	{ "cs6", IPTOS_DSCP_CS6 },
1691 	{ "cs7", IPTOS_DSCP_CS7 },
1692 	{ "ef", IPTOS_DSCP_EF },
1693 	{ "le", IPTOS_DSCP_LE },
1694 	{ "lowdelay", IPTOS_LOWDELAY },
1695 	{ "throughput", IPTOS_THROUGHPUT },
1696 	{ "reliability", IPTOS_RELIABILITY },
1697 	{ NULL, -1 }
1698 };
1699 
1700 int
1701 parse_ipqos(const char *cp)
1702 {
1703 	u_int i;
1704 	char *ep;
1705 	long val;
1706 
1707 	if (cp == NULL)
1708 		return -1;
1709 	for (i = 0; ipqos[i].name != NULL; i++) {
1710 		if (strcasecmp(cp, ipqos[i].name) == 0)
1711 			return ipqos[i].value;
1712 	}
1713 	/* Try parsing as an integer */
1714 	val = strtol(cp, &ep, 0);
1715 	if (*cp == '\0' || *ep != '\0' || val < 0 || val > 255)
1716 		return -1;
1717 	return val;
1718 }
1719 
1720 const char *
1721 iptos2str(int iptos)
1722 {
1723 	int i;
1724 	static char iptos_str[sizeof "0xff"];
1725 
1726 	for (i = 0; ipqos[i].name != NULL; i++) {
1727 		if (ipqos[i].value == iptos)
1728 			return ipqos[i].name;
1729 	}
1730 	snprintf(iptos_str, sizeof iptos_str, "0x%02x", iptos);
1731 	return iptos_str;
1732 }
1733 
1734 void
1735 lowercase(char *s)
1736 {
1737 	for (; *s; s++)
1738 		*s = tolower((u_char)*s);
1739 }
1740 
1741 int
1742 unix_listener(const char *path, int backlog, int unlink_first)
1743 {
1744 	struct sockaddr_un sunaddr;
1745 	int saved_errno, sock;
1746 
1747 	memset(&sunaddr, 0, sizeof(sunaddr));
1748 	sunaddr.sun_family = AF_UNIX;
1749 	if (strlcpy(sunaddr.sun_path, path,
1750 	    sizeof(sunaddr.sun_path)) >= sizeof(sunaddr.sun_path)) {
1751 		error_f("path \"%s\" too long for Unix domain socket", path);
1752 		errno = ENAMETOOLONG;
1753 		return -1;
1754 	}
1755 
1756 	sock = socket(PF_UNIX, SOCK_STREAM, 0);
1757 	if (sock == -1) {
1758 		saved_errno = errno;
1759 		error_f("socket: %.100s", strerror(errno));
1760 		errno = saved_errno;
1761 		return -1;
1762 	}
1763 	if (unlink_first == 1) {
1764 		if (unlink(path) != 0 && errno != ENOENT)
1765 			error("unlink(%s): %.100s", path, strerror(errno));
1766 	}
1767 	if (bind(sock, (struct sockaddr *)&sunaddr, sizeof(sunaddr)) == -1) {
1768 		saved_errno = errno;
1769 		error_f("cannot bind to path %s: %s", path, strerror(errno));
1770 		close(sock);
1771 		errno = saved_errno;
1772 		return -1;
1773 	}
1774 	if (listen(sock, backlog) == -1) {
1775 		saved_errno = errno;
1776 		error_f("cannot listen on path %s: %s", path, strerror(errno));
1777 		close(sock);
1778 		unlink(path);
1779 		errno = saved_errno;
1780 		return -1;
1781 	}
1782 	return sock;
1783 }
1784 
1785 /*
1786  * Compares two strings that maybe be NULL. Returns non-zero if strings
1787  * are both NULL or are identical, returns zero otherwise.
1788  */
1789 static int
1790 strcmp_maybe_null(const char *a, const char *b)
1791 {
1792 	if ((a == NULL && b != NULL) || (a != NULL && b == NULL))
1793 		return 0;
1794 	if (a != NULL && strcmp(a, b) != 0)
1795 		return 0;
1796 	return 1;
1797 }
1798 
1799 /*
1800  * Compare two forwards, returning non-zero if they are identical or
1801  * zero otherwise.
1802  */
1803 int
1804 forward_equals(const struct Forward *a, const struct Forward *b)
1805 {
1806 	if (strcmp_maybe_null(a->listen_host, b->listen_host) == 0)
1807 		return 0;
1808 	if (a->listen_port != b->listen_port)
1809 		return 0;
1810 	if (strcmp_maybe_null(a->listen_path, b->listen_path) == 0)
1811 		return 0;
1812 	if (strcmp_maybe_null(a->connect_host, b->connect_host) == 0)
1813 		return 0;
1814 	if (a->connect_port != b->connect_port)
1815 		return 0;
1816 	if (strcmp_maybe_null(a->connect_path, b->connect_path) == 0)
1817 		return 0;
1818 	/* allocated_port and handle are not checked */
1819 	return 1;
1820 }
1821 
1822 /* returns 1 if process is already daemonized, 0 otherwise */
1823 int
1824 daemonized(void)
1825 {
1826 	int fd;
1827 
1828 	if ((fd = open(_PATH_TTY, O_RDONLY | O_NOCTTY)) >= 0) {
1829 		close(fd);
1830 		return 0;	/* have controlling terminal */
1831 	}
1832 	if (getppid() != 1)
1833 		return 0;	/* parent is not init */
1834 	if (getsid(0) != getpid())
1835 		return 0;	/* not session leader */
1836 	debug3("already daemonized");
1837 	return 1;
1838 }
1839 
1840 /*
1841  * Splits 's' into an argument vector. Handles quoted string and basic
1842  * escape characters (\\, \", \'). Caller must free the argument vector
1843  * and its members.
1844  */
1845 int
1846 argv_split(const char *s, int *argcp, char ***argvp, int terminate_on_comment)
1847 {
1848 	int r = SSH_ERR_INTERNAL_ERROR;
1849 	int argc = 0, quote, i, j;
1850 	char *arg, **argv = xcalloc(1, sizeof(*argv));
1851 
1852 	*argvp = NULL;
1853 	*argcp = 0;
1854 
1855 	for (i = 0; s[i] != '\0'; i++) {
1856 		/* Skip leading whitespace */
1857 		if (s[i] == ' ' || s[i] == '\t')
1858 			continue;
1859 		if (terminate_on_comment && s[i] == '#')
1860 			break;
1861 		/* Start of a token */
1862 		quote = 0;
1863 
1864 		argv = xreallocarray(argv, (argc + 2), sizeof(*argv));
1865 		arg = argv[argc++] = xcalloc(1, strlen(s + i) + 1);
1866 		argv[argc] = NULL;
1867 
1868 		/* Copy the token in, removing escapes */
1869 		for (j = 0; s[i] != '\0'; i++) {
1870 			if (s[i] == '\\') {
1871 				if (s[i + 1] == '\'' ||
1872 				    s[i + 1] == '\"' ||
1873 				    s[i + 1] == '\\' ||
1874 				    (quote == 0 && s[i + 1] == ' ')) {
1875 					i++; /* Skip '\' */
1876 					arg[j++] = s[i];
1877 				} else {
1878 					/* Unrecognised escape */
1879 					arg[j++] = s[i];
1880 				}
1881 			} else if (quote == 0 && (s[i] == ' ' || s[i] == '\t'))
1882 				break; /* done */
1883 			else if (quote == 0 && (s[i] == '\"' || s[i] == '\''))
1884 				quote = s[i]; /* quote start */
1885 			else if (quote != 0 && s[i] == quote)
1886 				quote = 0; /* quote end */
1887 			else
1888 				arg[j++] = s[i];
1889 		}
1890 		if (s[i] == '\0') {
1891 			if (quote != 0) {
1892 				/* Ran out of string looking for close quote */
1893 				r = SSH_ERR_INVALID_FORMAT;
1894 				goto out;
1895 			}
1896 			break;
1897 		}
1898 	}
1899 	/* Success */
1900 	*argcp = argc;
1901 	*argvp = argv;
1902 	argc = 0;
1903 	argv = NULL;
1904 	r = 0;
1905  out:
1906 	if (argc != 0 && argv != NULL) {
1907 		for (i = 0; i < argc; i++)
1908 			free(argv[i]);
1909 		free(argv);
1910 	}
1911 	return r;
1912 }
1913 
1914 /*
1915  * Reassemble an argument vector into a string, quoting and escaping as
1916  * necessary. Caller must free returned string.
1917  */
1918 char *
1919 argv_assemble(int argc, char **argv)
1920 {
1921 	int i, j, ws, r;
1922 	char c, *ret;
1923 	struct sshbuf *buf, *arg;
1924 
1925 	if ((buf = sshbuf_new()) == NULL || (arg = sshbuf_new()) == NULL)
1926 		fatal_f("sshbuf_new failed");
1927 
1928 	for (i = 0; i < argc; i++) {
1929 		ws = 0;
1930 		sshbuf_reset(arg);
1931 		for (j = 0; argv[i][j] != '\0'; j++) {
1932 			r = 0;
1933 			c = argv[i][j];
1934 			switch (c) {
1935 			case ' ':
1936 			case '\t':
1937 				ws = 1;
1938 				r = sshbuf_put_u8(arg, c);
1939 				break;
1940 			case '\\':
1941 			case '\'':
1942 			case '"':
1943 				if ((r = sshbuf_put_u8(arg, '\\')) != 0)
1944 					break;
1945 				/* FALLTHROUGH */
1946 			default:
1947 				r = sshbuf_put_u8(arg, c);
1948 				break;
1949 			}
1950 			if (r != 0)
1951 				fatal_fr(r, "sshbuf_put_u8");
1952 		}
1953 		if ((i != 0 && (r = sshbuf_put_u8(buf, ' ')) != 0) ||
1954 		    (ws != 0 && (r = sshbuf_put_u8(buf, '"')) != 0) ||
1955 		    (r = sshbuf_putb(buf, arg)) != 0 ||
1956 		    (ws != 0 && (r = sshbuf_put_u8(buf, '"')) != 0))
1957 			fatal_fr(r, "assemble");
1958 	}
1959 	if ((ret = malloc(sshbuf_len(buf) + 1)) == NULL)
1960 		fatal_f("malloc failed");
1961 	memcpy(ret, sshbuf_ptr(buf), sshbuf_len(buf));
1962 	ret[sshbuf_len(buf)] = '\0';
1963 	sshbuf_free(buf);
1964 	sshbuf_free(arg);
1965 	return ret;
1966 }
1967 
1968 char *
1969 argv_next(int *argcp, char ***argvp)
1970 {
1971 	char *ret = (*argvp)[0];
1972 
1973 	if (*argcp > 0 && ret != NULL) {
1974 		(*argcp)--;
1975 		(*argvp)++;
1976 	}
1977 	return ret;
1978 }
1979 
1980 void
1981 argv_consume(int *argcp)
1982 {
1983 	*argcp = 0;
1984 }
1985 
1986 void
1987 argv_free(char **av, int ac)
1988 {
1989 	int i;
1990 
1991 	if (av == NULL)
1992 		return;
1993 	for (i = 0; i < ac; i++)
1994 		free(av[i]);
1995 	free(av);
1996 }
1997 
1998 /* Returns 0 if pid exited cleanly, non-zero otherwise */
1999 int
2000 exited_cleanly(pid_t pid, const char *tag, const char *cmd, int quiet)
2001 {
2002 	int status;
2003 
2004 	while (waitpid(pid, &status, 0) == -1) {
2005 		if (errno != EINTR) {
2006 			error("%s waitpid: %s", tag, strerror(errno));
2007 			return -1;
2008 		}
2009 	}
2010 	if (WIFSIGNALED(status)) {
2011 		error("%s %s exited on signal %d", tag, cmd, WTERMSIG(status));
2012 		return -1;
2013 	} else if (WEXITSTATUS(status) != 0) {
2014 		do_log2(quiet ? SYSLOG_LEVEL_DEBUG1 : SYSLOG_LEVEL_INFO,
2015 		    "%s %s failed, status %d", tag, cmd, WEXITSTATUS(status));
2016 		return -1;
2017 	}
2018 	return 0;
2019 }
2020 
2021 /*
2022  * Check a given path for security. This is defined as all components
2023  * of the path to the file must be owned by either the owner of
2024  * of the file or root and no directories must be group or world writable.
2025  *
2026  * XXX Should any specific check be done for sym links ?
2027  *
2028  * Takes a file name, its stat information (preferably from fstat() to
2029  * avoid races), the uid of the expected owner, their home directory and an
2030  * error buffer plus max size as arguments.
2031  *
2032  * Returns 0 on success and -1 on failure
2033  */
2034 int
2035 safe_path(const char *name, struct stat *stp, const char *pw_dir,
2036     uid_t uid, char *err, size_t errlen)
2037 {
2038 	char buf[PATH_MAX], homedir[PATH_MAX];
2039 	char *cp;
2040 	int comparehome = 0;
2041 	struct stat st;
2042 
2043 	if (realpath(name, buf) == NULL) {
2044 		snprintf(err, errlen, "realpath %s failed: %s", name,
2045 		    strerror(errno));
2046 		return -1;
2047 	}
2048 	if (pw_dir != NULL && realpath(pw_dir, homedir) != NULL)
2049 		comparehome = 1;
2050 
2051 	if (!S_ISREG(stp->st_mode)) {
2052 		snprintf(err, errlen, "%s is not a regular file", buf);
2053 		return -1;
2054 	}
2055 	if ((stp->st_uid != 0 && stp->st_uid != uid) ||
2056 	    (stp->st_mode & 022) != 0) {
2057 		snprintf(err, errlen, "bad ownership or modes for file %s",
2058 		    buf);
2059 		return -1;
2060 	}
2061 
2062 	/* for each component of the canonical path, walking upwards */
2063 	for (;;) {
2064 		if ((cp = dirname(buf)) == NULL) {
2065 			snprintf(err, errlen, "dirname() failed");
2066 			return -1;
2067 		}
2068 		strlcpy(buf, cp, sizeof(buf));
2069 
2070 		if (stat(buf, &st) == -1 ||
2071 		    (st.st_uid != 0 && st.st_uid != uid) ||
2072 		    (st.st_mode & 022) != 0) {
2073 			snprintf(err, errlen,
2074 			    "bad ownership or modes for directory %s", buf);
2075 			return -1;
2076 		}
2077 
2078 		/* If are past the homedir then we can stop */
2079 		if (comparehome && strcmp(homedir, buf) == 0)
2080 			break;
2081 
2082 		/*
2083 		 * dirname should always complete with a "/" path,
2084 		 * but we can be paranoid and check for "." too
2085 		 */
2086 		if ((strcmp("/", buf) == 0) || (strcmp(".", buf) == 0))
2087 			break;
2088 	}
2089 	return 0;
2090 }
2091 
2092 /*
2093  * Version of safe_path() that accepts an open file descriptor to
2094  * avoid races.
2095  *
2096  * Returns 0 on success and -1 on failure
2097  */
2098 int
2099 safe_path_fd(int fd, const char *file, struct passwd *pw,
2100     char *err, size_t errlen)
2101 {
2102 	struct stat st;
2103 
2104 	/* check the open file to avoid races */
2105 	if (fstat(fd, &st) == -1) {
2106 		snprintf(err, errlen, "cannot stat file %s: %s",
2107 		    file, strerror(errno));
2108 		return -1;
2109 	}
2110 	return safe_path(file, &st, pw->pw_dir, pw->pw_uid, err, errlen);
2111 }
2112 
2113 /*
2114  * Sets the value of the given variable in the environment.  If the variable
2115  * already exists, its value is overridden.
2116  */
2117 void
2118 child_set_env(char ***envp, u_int *envsizep, const char *name,
2119 	const char *value)
2120 {
2121 	char **env;
2122 	u_int envsize;
2123 	u_int i, namelen;
2124 
2125 	if (strchr(name, '=') != NULL) {
2126 		error("Invalid environment variable \"%.100s\"", name);
2127 		return;
2128 	}
2129 
2130 	/*
2131 	 * Find the slot where the value should be stored.  If the variable
2132 	 * already exists, we reuse the slot; otherwise we append a new slot
2133 	 * at the end of the array, expanding if necessary.
2134 	 */
2135 	env = *envp;
2136 	namelen = strlen(name);
2137 	for (i = 0; env[i]; i++)
2138 		if (strncmp(env[i], name, namelen) == 0 && env[i][namelen] == '=')
2139 			break;
2140 	if (env[i]) {
2141 		/* Reuse the slot. */
2142 		free(env[i]);
2143 	} else {
2144 		/* New variable.  Expand if necessary. */
2145 		envsize = *envsizep;
2146 		if (i >= envsize - 1) {
2147 			if (envsize >= 1000)
2148 				fatal("child_set_env: too many env vars");
2149 			envsize += 50;
2150 			env = (*envp) = xreallocarray(env, envsize, sizeof(char *));
2151 			*envsizep = envsize;
2152 		}
2153 		/* Need to set the NULL pointer at end of array beyond the new slot. */
2154 		env[i + 1] = NULL;
2155 	}
2156 
2157 	/* Allocate space and format the variable in the appropriate slot. */
2158 	/* XXX xasprintf */
2159 	env[i] = xmalloc(strlen(name) + 1 + strlen(value) + 1);
2160 	snprintf(env[i], strlen(name) + 1 + strlen(value) + 1, "%s=%s", name, value);
2161 }
2162 
2163 /*
2164  * Check and optionally lowercase a domain name, also removes trailing '.'
2165  * Returns 1 on success and 0 on failure, storing an error message in errstr.
2166  */
2167 int
2168 valid_domain(char *name, int makelower, const char **errstr)
2169 {
2170 	size_t i, l = strlen(name);
2171 	u_char c, last = '\0';
2172 	static char errbuf[256];
2173 
2174 	if (l == 0) {
2175 		strlcpy(errbuf, "empty domain name", sizeof(errbuf));
2176 		goto bad;
2177 	}
2178 	if (!isalpha((u_char)name[0]) && !isdigit((u_char)name[0])) {
2179 		snprintf(errbuf, sizeof(errbuf), "domain name \"%.100s\" "
2180 		    "starts with invalid character", name);
2181 		goto bad;
2182 	}
2183 	for (i = 0; i < l; i++) {
2184 		c = tolower((u_char)name[i]);
2185 		if (makelower)
2186 			name[i] = (char)c;
2187 		if (last == '.' && c == '.') {
2188 			snprintf(errbuf, sizeof(errbuf), "domain name "
2189 			    "\"%.100s\" contains consecutive separators", name);
2190 			goto bad;
2191 		}
2192 		if (c != '.' && c != '-' && !isalnum(c) &&
2193 		    c != '_') /* technically invalid, but common */ {
2194 			snprintf(errbuf, sizeof(errbuf), "domain name "
2195 			    "\"%.100s\" contains invalid characters", name);
2196 			goto bad;
2197 		}
2198 		last = c;
2199 	}
2200 	if (name[l - 1] == '.')
2201 		name[l - 1] = '\0';
2202 	if (errstr != NULL)
2203 		*errstr = NULL;
2204 	return 1;
2205 bad:
2206 	if (errstr != NULL)
2207 		*errstr = errbuf;
2208 	return 0;
2209 }
2210 
2211 /*
2212  * Verify that a environment variable name (not including initial '$') is
2213  * valid; consisting of one or more alphanumeric or underscore characters only.
2214  * Returns 1 on valid, 0 otherwise.
2215  */
2216 int
2217 valid_env_name(const char *name)
2218 {
2219 	const char *cp;
2220 
2221 	if (name[0] == '\0')
2222 		return 0;
2223 	for (cp = name; *cp != '\0'; cp++) {
2224 		if (!isalnum((u_char)*cp) && *cp != '_')
2225 			return 0;
2226 	}
2227 	return 1;
2228 }
2229 
2230 const char *
2231 atoi_err(const char *nptr, int *val)
2232 {
2233 	const char *errstr = NULL;
2234 	long long num;
2235 
2236 	if (nptr == NULL || *nptr == '\0')
2237 		return "missing";
2238 	num = strtonum(nptr, 0, INT_MAX, &errstr);
2239 	if (errstr == NULL)
2240 		*val = (int)num;
2241 	return errstr;
2242 }
2243 
2244 int
2245 parse_absolute_time(const char *s, uint64_t *tp)
2246 {
2247 	struct tm tm;
2248 	time_t tt;
2249 	char buf[32], *fmt;
2250 
2251 	*tp = 0;
2252 
2253 	/*
2254 	 * POSIX strptime says "The application shall ensure that there
2255 	 * is white-space or other non-alphanumeric characters between
2256 	 * any two conversion specifications" so arrange things this way.
2257 	 */
2258 	switch (strlen(s)) {
2259 	case 8: /* YYYYMMDD */
2260 		fmt = "%Y-%m-%d";
2261 		snprintf(buf, sizeof(buf), "%.4s-%.2s-%.2s", s, s + 4, s + 6);
2262 		break;
2263 	case 12: /* YYYYMMDDHHMM */
2264 		fmt = "%Y-%m-%dT%H:%M";
2265 		snprintf(buf, sizeof(buf), "%.4s-%.2s-%.2sT%.2s:%.2s",
2266 		    s, s + 4, s + 6, s + 8, s + 10);
2267 		break;
2268 	case 14: /* YYYYMMDDHHMMSS */
2269 		fmt = "%Y-%m-%dT%H:%M:%S";
2270 		snprintf(buf, sizeof(buf), "%.4s-%.2s-%.2sT%.2s:%.2s:%.2s",
2271 		    s, s + 4, s + 6, s + 8, s + 10, s + 12);
2272 		break;
2273 	default:
2274 		return SSH_ERR_INVALID_FORMAT;
2275 	}
2276 
2277 	memset(&tm, 0, sizeof(tm));
2278 	if (strptime(buf, fmt, &tm) == NULL)
2279 		return SSH_ERR_INVALID_FORMAT;
2280 	if ((tt = mktime(&tm)) < 0)
2281 		return SSH_ERR_INVALID_FORMAT;
2282 	/* success */
2283 	*tp = (uint64_t)tt;
2284 	return 0;
2285 }
2286 
2287 /* On OpenBSD time_t is int64_t which is long long. */
2288 #define SSH_TIME_T_MAX LLONG_MAX
2289 
2290 void
2291 format_absolute_time(uint64_t t, char *buf, size_t len)
2292 {
2293 	time_t tt = t > SSH_TIME_T_MAX ? SSH_TIME_T_MAX : t;
2294 	struct tm tm;
2295 
2296 	localtime_r(&tt, &tm);
2297 	strftime(buf, len, "%Y-%m-%dT%H:%M:%S", &tm);
2298 }
2299 
2300 /* check if path is absolute */
2301 int
2302 path_absolute(const char *path)
2303 {
2304 	return (*path == '/') ? 1 : 0;
2305 }
2306 
2307 void
2308 skip_space(char **cpp)
2309 {
2310 	char *cp;
2311 
2312 	for (cp = *cpp; *cp == ' ' || *cp == '\t'; cp++)
2313 		;
2314 	*cpp = cp;
2315 }
2316 
2317 /* authorized_key-style options parsing helpers */
2318 
2319 /*
2320  * Match flag 'opt' in *optsp, and if allow_negate is set then also match
2321  * 'no-opt'. Returns -1 if option not matched, 1 if option matches or 0
2322  * if negated option matches.
2323  * If the option or negated option matches, then *optsp is updated to
2324  * point to the first character after the option.
2325  */
2326 int
2327 opt_flag(const char *opt, int allow_negate, const char **optsp)
2328 {
2329 	size_t opt_len = strlen(opt);
2330 	const char *opts = *optsp;
2331 	int negate = 0;
2332 
2333 	if (allow_negate && strncasecmp(opts, "no-", 3) == 0) {
2334 		opts += 3;
2335 		negate = 1;
2336 	}
2337 	if (strncasecmp(opts, opt, opt_len) == 0) {
2338 		*optsp = opts + opt_len;
2339 		return negate ? 0 : 1;
2340 	}
2341 	return -1;
2342 }
2343 
2344 char *
2345 opt_dequote(const char **sp, const char **errstrp)
2346 {
2347 	const char *s = *sp;
2348 	char *ret;
2349 	size_t i;
2350 
2351 	*errstrp = NULL;
2352 	if (*s != '"') {
2353 		*errstrp = "missing start quote";
2354 		return NULL;
2355 	}
2356 	s++;
2357 	if ((ret = malloc(strlen((s)) + 1)) == NULL) {
2358 		*errstrp = "memory allocation failed";
2359 		return NULL;
2360 	}
2361 	for (i = 0; *s != '\0' && *s != '"';) {
2362 		if (s[0] == '\\' && s[1] == '"')
2363 			s++;
2364 		ret[i++] = *s++;
2365 	}
2366 	if (*s == '\0') {
2367 		*errstrp = "missing end quote";
2368 		free(ret);
2369 		return NULL;
2370 	}
2371 	ret[i] = '\0';
2372 	s++;
2373 	*sp = s;
2374 	return ret;
2375 }
2376 
2377 int
2378 opt_match(const char **opts, const char *term)
2379 {
2380 	if (strncasecmp((*opts), term, strlen(term)) == 0 &&
2381 	    (*opts)[strlen(term)] == '=') {
2382 		*opts += strlen(term) + 1;
2383 		return 1;
2384 	}
2385 	return 0;
2386 }
2387 
2388 void
2389 opt_array_append2(const char *file, const int line, const char *directive,
2390     char ***array, int **iarray, u_int *lp, const char *s, int i)
2391 {
2392 
2393 	if (*lp >= INT_MAX)
2394 		fatal("%s line %d: Too many %s entries", file, line, directive);
2395 
2396 	if (iarray != NULL) {
2397 		*iarray = xrecallocarray(*iarray, *lp, *lp + 1,
2398 		    sizeof(**iarray));
2399 		(*iarray)[*lp] = i;
2400 	}
2401 
2402 	*array = xrecallocarray(*array, *lp, *lp + 1, sizeof(**array));
2403 	(*array)[*lp] = xstrdup(s);
2404 	(*lp)++;
2405 }
2406 
2407 void
2408 opt_array_append(const char *file, const int line, const char *directive,
2409     char ***array, u_int *lp, const char *s)
2410 {
2411 	opt_array_append2(file, line, directive, array, NULL, lp, s, 0);
2412 }
2413 
2414 sshsig_t
2415 ssh_signal(int signum, sshsig_t handler)
2416 {
2417 	struct sigaction sa, osa;
2418 
2419 	/* mask all other signals while in handler */
2420 	memset(&sa, 0, sizeof(sa));
2421 	sa.sa_handler = handler;
2422 	sigfillset(&sa.sa_mask);
2423 	if (signum != SIGALRM)
2424 		sa.sa_flags = SA_RESTART;
2425 	if (sigaction(signum, &sa, &osa) == -1) {
2426 		debug3("sigaction(%s): %s", strsignal(signum), strerror(errno));
2427 		return SIG_ERR;
2428 	}
2429 	return osa.sa_handler;
2430 }
2431 
2432 int
2433 stdfd_devnull(int do_stdin, int do_stdout, int do_stderr)
2434 {
2435 	int devnull, ret = 0;
2436 
2437 	if ((devnull = open(_PATH_DEVNULL, O_RDWR)) == -1) {
2438 		error_f("open %s: %s", _PATH_DEVNULL,
2439 		    strerror(errno));
2440 		return -1;
2441 	}
2442 	if ((do_stdin && dup2(devnull, STDIN_FILENO) == -1) ||
2443 	    (do_stdout && dup2(devnull, STDOUT_FILENO) == -1) ||
2444 	    (do_stderr && dup2(devnull, STDERR_FILENO) == -1)) {
2445 		error_f("dup2: %s", strerror(errno));
2446 		ret = -1;
2447 	}
2448 	if (devnull > STDERR_FILENO)
2449 		close(devnull);
2450 	return ret;
2451 }
2452 
2453 /*
2454  * Runs command in a subprocess with a minimal environment.
2455  * Returns pid on success, 0 on failure.
2456  * The child stdout and stderr maybe captured, left attached or sent to
2457  * /dev/null depending on the contents of flags.
2458  * "tag" is prepended to log messages.
2459  * NB. "command" is only used for logging; the actual command executed is
2460  * av[0].
2461  */
2462 pid_t
2463 subprocess(const char *tag, const char *command,
2464     int ac, char **av, FILE **child, u_int flags,
2465     struct passwd *pw, privdrop_fn *drop_privs, privrestore_fn *restore_privs)
2466 {
2467 	FILE *f = NULL;
2468 	struct stat st;
2469 	int fd, devnull, p[2], i;
2470 	pid_t pid;
2471 	char *cp, errmsg[512];
2472 	u_int nenv = 0;
2473 	char **env = NULL;
2474 
2475 	/* If dropping privs, then must specify user and restore function */
2476 	if (drop_privs != NULL && (pw == NULL || restore_privs == NULL)) {
2477 		error("%s: inconsistent arguments", tag); /* XXX fatal? */
2478 		return 0;
2479 	}
2480 	if (pw == NULL && (pw = getpwuid(getuid())) == NULL) {
2481 		error("%s: no user for current uid", tag);
2482 		return 0;
2483 	}
2484 	if (child != NULL)
2485 		*child = NULL;
2486 
2487 	debug3_f("%s command \"%s\" running as %s (flags 0x%x)",
2488 	    tag, command, pw->pw_name, flags);
2489 
2490 	/* Check consistency */
2491 	if ((flags & SSH_SUBPROCESS_STDOUT_DISCARD) != 0 &&
2492 	    (flags & SSH_SUBPROCESS_STDOUT_CAPTURE) != 0) {
2493 		error_f("inconsistent flags");
2494 		return 0;
2495 	}
2496 	if (((flags & SSH_SUBPROCESS_STDOUT_CAPTURE) == 0) != (child == NULL)) {
2497 		error_f("inconsistent flags/output");
2498 		return 0;
2499 	}
2500 
2501 	/*
2502 	 * If executing an explicit binary, then verify the it exists
2503 	 * and appears safe-ish to execute
2504 	 */
2505 	if (!path_absolute(av[0])) {
2506 		error("%s path is not absolute", tag);
2507 		return 0;
2508 	}
2509 	if (drop_privs != NULL)
2510 		drop_privs(pw);
2511 	if (stat(av[0], &st) == -1) {
2512 		error("Could not stat %s \"%s\": %s", tag,
2513 		    av[0], strerror(errno));
2514 		goto restore_return;
2515 	}
2516 	if ((flags & SSH_SUBPROCESS_UNSAFE_PATH) == 0 &&
2517 	    safe_path(av[0], &st, NULL, 0, errmsg, sizeof(errmsg)) != 0) {
2518 		error("Unsafe %s \"%s\": %s", tag, av[0], errmsg);
2519 		goto restore_return;
2520 	}
2521 	/* Prepare to keep the child's stdout if requested */
2522 	if (pipe(p) == -1) {
2523 		error("%s: pipe: %s", tag, strerror(errno));
2524  restore_return:
2525 		if (restore_privs != NULL)
2526 			restore_privs();
2527 		return 0;
2528 	}
2529 	if (restore_privs != NULL)
2530 		restore_privs();
2531 
2532 	switch ((pid = fork())) {
2533 	case -1: /* error */
2534 		error("%s: fork: %s", tag, strerror(errno));
2535 		close(p[0]);
2536 		close(p[1]);
2537 		return 0;
2538 	case 0: /* child */
2539 		/* Prepare a minimal environment for the child. */
2540 		if ((flags & SSH_SUBPROCESS_PRESERVE_ENV) == 0) {
2541 			nenv = 5;
2542 			env = xcalloc(sizeof(*env), nenv);
2543 			child_set_env(&env, &nenv, "PATH", _PATH_STDPATH);
2544 			child_set_env(&env, &nenv, "USER", pw->pw_name);
2545 			child_set_env(&env, &nenv, "LOGNAME", pw->pw_name);
2546 			child_set_env(&env, &nenv, "HOME", pw->pw_dir);
2547 			if ((cp = getenv("LANG")) != NULL)
2548 				child_set_env(&env, &nenv, "LANG", cp);
2549 		}
2550 
2551 		for (i = 1; i < NSIG; i++)
2552 			ssh_signal(i, SIG_DFL);
2553 
2554 		if ((devnull = open(_PATH_DEVNULL, O_RDWR)) == -1) {
2555 			error("%s: open %s: %s", tag, _PATH_DEVNULL,
2556 			    strerror(errno));
2557 			_exit(1);
2558 		}
2559 		if (dup2(devnull, STDIN_FILENO) == -1) {
2560 			error("%s: dup2: %s", tag, strerror(errno));
2561 			_exit(1);
2562 		}
2563 
2564 		/* Set up stdout as requested; leave stderr in place for now. */
2565 		fd = -1;
2566 		if ((flags & SSH_SUBPROCESS_STDOUT_CAPTURE) != 0)
2567 			fd = p[1];
2568 		else if ((flags & SSH_SUBPROCESS_STDOUT_DISCARD) != 0)
2569 			fd = devnull;
2570 		if (fd != -1 && dup2(fd, STDOUT_FILENO) == -1) {
2571 			error("%s: dup2: %s", tag, strerror(errno));
2572 			_exit(1);
2573 		}
2574 		closefrom(STDERR_FILENO + 1);
2575 
2576 		if (setresgid(pw->pw_gid, pw->pw_gid, pw->pw_gid) == -1) {
2577 			error("%s: setresgid %u: %s", tag, (u_int)pw->pw_gid,
2578 			    strerror(errno));
2579 			_exit(1);
2580 		}
2581 		if (setresuid(pw->pw_uid, pw->pw_uid, pw->pw_uid) == -1) {
2582 			error("%s: setresuid %u: %s", tag, (u_int)pw->pw_uid,
2583 			    strerror(errno));
2584 			_exit(1);
2585 		}
2586 		/* stdin is pointed to /dev/null at this point */
2587 		if ((flags & SSH_SUBPROCESS_STDOUT_DISCARD) != 0 &&
2588 		    dup2(STDIN_FILENO, STDERR_FILENO) == -1) {
2589 			error("%s: dup2: %s", tag, strerror(errno));
2590 			_exit(1);
2591 		}
2592 		if (env != NULL)
2593 			execve(av[0], av, env);
2594 		else
2595 			execv(av[0], av);
2596 		error("%s %s \"%s\": %s", tag, env == NULL ? "execv" : "execve",
2597 		    command, strerror(errno));
2598 		_exit(127);
2599 	default: /* parent */
2600 		break;
2601 	}
2602 
2603 	close(p[1]);
2604 	if ((flags & SSH_SUBPROCESS_STDOUT_CAPTURE) == 0)
2605 		close(p[0]);
2606 	else if ((f = fdopen(p[0], "r")) == NULL) {
2607 		error("%s: fdopen: %s", tag, strerror(errno));
2608 		close(p[0]);
2609 		/* Don't leave zombie child */
2610 		kill(pid, SIGTERM);
2611 		while (waitpid(pid, NULL, 0) == -1 && errno == EINTR)
2612 			;
2613 		return 0;
2614 	}
2615 	/* Success */
2616 	debug3_f("%s pid %ld", tag, (long)pid);
2617 	if (child != NULL)
2618 		*child = f;
2619 	return pid;
2620 }
2621 
2622 const char *
2623 lookup_env_in_list(const char *env, char * const *envs, size_t nenvs)
2624 {
2625 	size_t i, envlen;
2626 
2627 	envlen = strlen(env);
2628 	for (i = 0; i < nenvs; i++) {
2629 		if (strncmp(envs[i], env, envlen) == 0 &&
2630 		    envs[i][envlen] == '=') {
2631 			return envs[i] + envlen + 1;
2632 		}
2633 	}
2634 	return NULL;
2635 }
2636