xref: /freebsd/crypto/openssh/misc.c (revision b3e7694832e81d7a904a10f525f8797b753bf0d3)
1 /* $OpenBSD: misc.c,v 1.185 2023/08/04 06:32:40 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 "includes.h"
22 
23 #include <sys/types.h>
24 #include <sys/ioctl.h>
25 #include <sys/mman.h>
26 #include <sys/socket.h>
27 #include <sys/stat.h>
28 #include <sys/time.h>
29 #include <sys/wait.h>
30 #include <sys/un.h>
31 
32 #include <limits.h>
33 #ifdef HAVE_LIBGEN_H
34 # include <libgen.h>
35 #endif
36 #ifdef HAVE_POLL_H
37 #include <poll.h>
38 #endif
39 #ifdef HAVE_NLIST_H
40 #include <nlist.h>
41 #endif
42 #include <signal.h>
43 #include <stdarg.h>
44 #include <stdio.h>
45 #ifdef HAVE_STDINT_H
46 # include <stdint.h>
47 #endif
48 #include <stdlib.h>
49 #include <string.h>
50 #include <time.h>
51 #include <unistd.h>
52 
53 #include <netinet/in.h>
54 #include <netinet/in_systm.h>
55 #include <netinet/ip.h>
56 #include <netinet/tcp.h>
57 #include <arpa/inet.h>
58 
59 #include <ctype.h>
60 #include <errno.h>
61 #include <fcntl.h>
62 #include <netdb.h>
63 #ifdef HAVE_PATHS_H
64 # include <paths.h>
65 #include <pwd.h>
66 #include <grp.h>
67 #endif
68 #ifdef SSH_TUN_OPENBSD
69 #include <net/if.h>
70 #endif
71 
72 #include "xmalloc.h"
73 #include "misc.h"
74 #include "log.h"
75 #include "ssh.h"
76 #include "sshbuf.h"
77 #include "ssherr.h"
78 #include "platform.h"
79 
80 /* remove newline at end of string */
81 char *
82 chop(char *s)
83 {
84 	char *t = s;
85 	while (*t) {
86 		if (*t == '\n' || *t == '\r') {
87 			*t = '\0';
88 			return s;
89 		}
90 		t++;
91 	}
92 	return s;
93 
94 }
95 
96 /* remove whitespace from end of string */
97 void
98 rtrim(char *s)
99 {
100 	size_t i;
101 
102 	if ((i = strlen(s)) == 0)
103 		return;
104 	for (i--; i > 0; i--) {
105 		if (isspace((unsigned char)s[i]))
106 			s[i] = '\0';
107 	}
108 }
109 
110 /* set/unset filedescriptor to non-blocking */
111 int
112 set_nonblock(int fd)
113 {
114 	int val;
115 
116 	val = fcntl(fd, F_GETFL);
117 	if (val == -1) {
118 		error("fcntl(%d, F_GETFL): %s", fd, strerror(errno));
119 		return (-1);
120 	}
121 	if (val & O_NONBLOCK) {
122 		debug3("fd %d is O_NONBLOCK", fd);
123 		return (0);
124 	}
125 	debug2("fd %d setting O_NONBLOCK", fd);
126 	val |= O_NONBLOCK;
127 	if (fcntl(fd, F_SETFL, val) == -1) {
128 		debug("fcntl(%d, F_SETFL, O_NONBLOCK): %s", fd,
129 		    strerror(errno));
130 		return (-1);
131 	}
132 	return (0);
133 }
134 
135 int
136 unset_nonblock(int fd)
137 {
138 	int val;
139 
140 	val = fcntl(fd, F_GETFL);
141 	if (val == -1) {
142 		error("fcntl(%d, F_GETFL): %s", fd, strerror(errno));
143 		return (-1);
144 	}
145 	if (!(val & O_NONBLOCK)) {
146 		debug3("fd %d is not O_NONBLOCK", fd);
147 		return (0);
148 	}
149 	debug("fd %d clearing O_NONBLOCK", fd);
150 	val &= ~O_NONBLOCK;
151 	if (fcntl(fd, F_SETFL, val) == -1) {
152 		debug("fcntl(%d, F_SETFL, ~O_NONBLOCK): %s",
153 		    fd, strerror(errno));
154 		return (-1);
155 	}
156 	return (0);
157 }
158 
159 const char *
160 ssh_gai_strerror(int gaierr)
161 {
162 	if (gaierr == EAI_SYSTEM && errno != 0)
163 		return strerror(errno);
164 	return gai_strerror(gaierr);
165 }
166 
167 /* disable nagle on socket */
168 void
169 set_nodelay(int fd)
170 {
171 	int opt;
172 	socklen_t optlen;
173 
174 	optlen = sizeof opt;
175 	if (getsockopt(fd, IPPROTO_TCP, TCP_NODELAY, &opt, &optlen) == -1) {
176 		debug("getsockopt TCP_NODELAY: %.100s", strerror(errno));
177 		return;
178 	}
179 	if (opt == 1) {
180 		debug2("fd %d is TCP_NODELAY", fd);
181 		return;
182 	}
183 	opt = 1;
184 	debug2("fd %d setting TCP_NODELAY", fd);
185 	if (setsockopt(fd, IPPROTO_TCP, TCP_NODELAY, &opt, sizeof opt) == -1)
186 		error("setsockopt TCP_NODELAY: %.100s", strerror(errno));
187 }
188 
189 /* Allow local port reuse in TIME_WAIT */
190 int
191 set_reuseaddr(int fd)
192 {
193 	int on = 1;
194 
195 	if (setsockopt(fd, SOL_SOCKET, SO_REUSEADDR, &on, sizeof(on)) == -1) {
196 		error("setsockopt SO_REUSEADDR fd %d: %s", fd, strerror(errno));
197 		return -1;
198 	}
199 	return 0;
200 }
201 
202 /* Get/set routing domain */
203 char *
204 get_rdomain(int fd)
205 {
206 #if defined(HAVE_SYS_GET_RDOMAIN)
207 	return sys_get_rdomain(fd);
208 #elif defined(__OpenBSD__)
209 	int rtable;
210 	char *ret;
211 	socklen_t len = sizeof(rtable);
212 
213 	if (getsockopt(fd, SOL_SOCKET, SO_RTABLE, &rtable, &len) == -1) {
214 		error("Failed to get routing domain for fd %d: %s",
215 		    fd, strerror(errno));
216 		return NULL;
217 	}
218 	xasprintf(&ret, "%d", rtable);
219 	return ret;
220 #else /* defined(__OpenBSD__) */
221 	return NULL;
222 #endif
223 }
224 
225 int
226 set_rdomain(int fd, const char *name)
227 {
228 #if defined(HAVE_SYS_SET_RDOMAIN)
229 	return sys_set_rdomain(fd, name);
230 #elif defined(__OpenBSD__)
231 	int rtable;
232 	const char *errstr;
233 
234 	if (name == NULL)
235 		return 0; /* default table */
236 
237 	rtable = (int)strtonum(name, 0, 255, &errstr);
238 	if (errstr != NULL) {
239 		/* Shouldn't happen */
240 		error("Invalid routing domain \"%s\": %s", name, errstr);
241 		return -1;
242 	}
243 	if (setsockopt(fd, SOL_SOCKET, SO_RTABLE,
244 	    &rtable, sizeof(rtable)) == -1) {
245 		error("Failed to set routing domain %d on fd %d: %s",
246 		    rtable, fd, strerror(errno));
247 		return -1;
248 	}
249 	return 0;
250 #else /* defined(__OpenBSD__) */
251 	error("Setting routing domain is not supported on this platform");
252 	return -1;
253 #endif
254 }
255 
256 int
257 get_sock_af(int fd)
258 {
259 	struct sockaddr_storage to;
260 	socklen_t tolen = sizeof(to);
261 
262 	memset(&to, 0, sizeof(to));
263 	if (getsockname(fd, (struct sockaddr *)&to, &tolen) == -1)
264 		return -1;
265 #ifdef IPV4_IN_IPV6
266 	if (to.ss_family == AF_INET6 &&
267 	    IN6_IS_ADDR_V4MAPPED(&((struct sockaddr_in6 *)&to)->sin6_addr))
268 		return AF_INET;
269 #endif
270 	return to.ss_family;
271 }
272 
273 void
274 set_sock_tos(int fd, int tos)
275 {
276 #ifndef IP_TOS_IS_BROKEN
277 	int af;
278 
279 	switch ((af = get_sock_af(fd))) {
280 	case -1:
281 		/* assume not a socket */
282 		break;
283 	case AF_INET:
284 # ifdef IP_TOS
285 		debug3_f("set socket %d IP_TOS 0x%02x", fd, tos);
286 		if (setsockopt(fd, IPPROTO_IP, IP_TOS,
287 		    &tos, sizeof(tos)) == -1) {
288 			error("setsockopt socket %d IP_TOS %d: %s",
289 			    fd, tos, strerror(errno));
290 		}
291 # endif /* IP_TOS */
292 		break;
293 	case AF_INET6:
294 # ifdef IPV6_TCLASS
295 		debug3_f("set socket %d IPV6_TCLASS 0x%02x", fd, tos);
296 		if (setsockopt(fd, IPPROTO_IPV6, IPV6_TCLASS,
297 		    &tos, sizeof(tos)) == -1) {
298 			error("setsockopt socket %d IPV6_TCLASS %d: %s",
299 			    fd, tos, strerror(errno));
300 		}
301 # endif /* IPV6_TCLASS */
302 		break;
303 	default:
304 		debug2_f("unsupported socket family %d", af);
305 		break;
306 	}
307 #endif /* IP_TOS_IS_BROKEN */
308 }
309 
310 /*
311  * Wait up to *timeoutp milliseconds for events on fd. Updates
312  * *timeoutp with time remaining.
313  * Returns 0 if fd ready or -1 on timeout or error (see errno).
314  */
315 static int
316 waitfd(int fd, int *timeoutp, short events)
317 {
318 	struct pollfd pfd;
319 	struct timeval t_start;
320 	int oerrno, r, have_timeout = (*timeoutp >= 0);
321 
322 	pfd.fd = fd;
323 	pfd.events = events;
324 	for (; !have_timeout || *timeoutp >= 0;) {
325 		monotime_tv(&t_start);
326 		r = poll(&pfd, 1, *timeoutp);
327 		oerrno = errno;
328 		if (have_timeout)
329 			ms_subtract_diff(&t_start, timeoutp);
330 		errno = oerrno;
331 		if (r > 0)
332 			return 0;
333 		else if (r == -1 && errno != EAGAIN && errno != EINTR)
334 			return -1;
335 		else if (r == 0)
336 			break;
337 	}
338 	/* timeout */
339 	errno = ETIMEDOUT;
340 	return -1;
341 }
342 
343 /*
344  * Wait up to *timeoutp milliseconds for fd to be readable. Updates
345  * *timeoutp with time remaining.
346  * Returns 0 if fd ready or -1 on timeout or error (see errno).
347  */
348 int
349 waitrfd(int fd, int *timeoutp) {
350 	return waitfd(fd, timeoutp, POLLIN);
351 }
352 
353 /*
354  * Attempt a non-blocking connect(2) to the specified address, waiting up to
355  * *timeoutp milliseconds for the connection to complete. If the timeout is
356  * <=0, then wait indefinitely.
357  *
358  * Returns 0 on success or -1 on failure.
359  */
360 int
361 timeout_connect(int sockfd, const struct sockaddr *serv_addr,
362     socklen_t addrlen, int *timeoutp)
363 {
364 	int optval = 0;
365 	socklen_t optlen = sizeof(optval);
366 
367 	/* No timeout: just do a blocking connect() */
368 	if (timeoutp == NULL || *timeoutp <= 0)
369 		return connect(sockfd, serv_addr, addrlen);
370 
371 	set_nonblock(sockfd);
372 	for (;;) {
373 		if (connect(sockfd, serv_addr, addrlen) == 0) {
374 			/* Succeeded already? */
375 			unset_nonblock(sockfd);
376 			return 0;
377 		} else if (errno == EINTR)
378 			continue;
379 		else if (errno != EINPROGRESS)
380 			return -1;
381 		break;
382 	}
383 
384 	if (waitfd(sockfd, timeoutp, POLLIN | POLLOUT) == -1)
385 		return -1;
386 
387 	/* Completed or failed */
388 	if (getsockopt(sockfd, SOL_SOCKET, SO_ERROR, &optval, &optlen) == -1) {
389 		debug("getsockopt: %s", strerror(errno));
390 		return -1;
391 	}
392 	if (optval != 0) {
393 		errno = optval;
394 		return -1;
395 	}
396 	unset_nonblock(sockfd);
397 	return 0;
398 }
399 
400 /* Characters considered whitespace in strsep calls. */
401 #define WHITESPACE " \t\r\n"
402 #define QUOTE	"\""
403 
404 /* return next token in configuration line */
405 static char *
406 strdelim_internal(char **s, int split_equals)
407 {
408 	char *old;
409 	int wspace = 0;
410 
411 	if (*s == NULL)
412 		return NULL;
413 
414 	old = *s;
415 
416 	*s = strpbrk(*s,
417 	    split_equals ? WHITESPACE QUOTE "=" : WHITESPACE QUOTE);
418 	if (*s == NULL)
419 		return (old);
420 
421 	if (*s[0] == '\"') {
422 		memmove(*s, *s + 1, strlen(*s)); /* move nul too */
423 		/* Find matching quote */
424 		if ((*s = strpbrk(*s, QUOTE)) == NULL) {
425 			return (NULL);		/* no matching quote */
426 		} else {
427 			*s[0] = '\0';
428 			*s += strspn(*s + 1, WHITESPACE) + 1;
429 			return (old);
430 		}
431 	}
432 
433 	/* Allow only one '=' to be skipped */
434 	if (split_equals && *s[0] == '=')
435 		wspace = 1;
436 	*s[0] = '\0';
437 
438 	/* Skip any extra whitespace after first token */
439 	*s += strspn(*s + 1, WHITESPACE) + 1;
440 	if (split_equals && *s[0] == '=' && !wspace)
441 		*s += strspn(*s + 1, WHITESPACE) + 1;
442 
443 	return (old);
444 }
445 
446 /*
447  * Return next token in configuration line; splts on whitespace or a
448  * single '=' character.
449  */
450 char *
451 strdelim(char **s)
452 {
453 	return strdelim_internal(s, 1);
454 }
455 
456 /*
457  * Return next token in configuration line; splts on whitespace only.
458  */
459 char *
460 strdelimw(char **s)
461 {
462 	return strdelim_internal(s, 0);
463 }
464 
465 struct passwd *
466 pwcopy(struct passwd *pw)
467 {
468 	struct passwd *copy = xcalloc(1, sizeof(*copy));
469 
470 	copy->pw_name = xstrdup(pw->pw_name);
471 	copy->pw_passwd = xstrdup(pw->pw_passwd == NULL ? "*" : pw->pw_passwd);
472 #ifdef HAVE_STRUCT_PASSWD_PW_GECOS
473 	copy->pw_gecos = xstrdup(pw->pw_gecos);
474 #endif
475 	copy->pw_uid = pw->pw_uid;
476 	copy->pw_gid = pw->pw_gid;
477 #ifdef HAVE_STRUCT_PASSWD_PW_EXPIRE
478 	copy->pw_expire = pw->pw_expire;
479 #endif
480 #ifdef HAVE_STRUCT_PASSWD_PW_CHANGE
481 	copy->pw_change = pw->pw_change;
482 #endif
483 #ifdef HAVE_STRUCT_PASSWD_PW_CLASS
484 	copy->pw_class = xstrdup(pw->pw_class);
485 #endif
486 	copy->pw_dir = xstrdup(pw->pw_dir);
487 	copy->pw_shell = xstrdup(pw->pw_shell);
488 	return copy;
489 }
490 
491 /*
492  * Convert ASCII string to TCP/IP port number.
493  * Port must be >=0 and <=65535.
494  * Return -1 if invalid.
495  */
496 int
497 a2port(const char *s)
498 {
499 	struct servent *se;
500 	long long port;
501 	const char *errstr;
502 
503 	port = strtonum(s, 0, 65535, &errstr);
504 	if (errstr == NULL)
505 		return (int)port;
506 	if ((se = getservbyname(s, "tcp")) != NULL)
507 		return ntohs(se->s_port);
508 	return -1;
509 }
510 
511 int
512 a2tun(const char *s, int *remote)
513 {
514 	const char *errstr = NULL;
515 	char *sp, *ep;
516 	int tun;
517 
518 	if (remote != NULL) {
519 		*remote = SSH_TUNID_ANY;
520 		sp = xstrdup(s);
521 		if ((ep = strchr(sp, ':')) == NULL) {
522 			free(sp);
523 			return (a2tun(s, NULL));
524 		}
525 		ep[0] = '\0'; ep++;
526 		*remote = a2tun(ep, NULL);
527 		tun = a2tun(sp, NULL);
528 		free(sp);
529 		return (*remote == SSH_TUNID_ERR ? *remote : tun);
530 	}
531 
532 	if (strcasecmp(s, "any") == 0)
533 		return (SSH_TUNID_ANY);
534 
535 	tun = strtonum(s, 0, SSH_TUNID_MAX, &errstr);
536 	if (errstr != NULL)
537 		return (SSH_TUNID_ERR);
538 
539 	return (tun);
540 }
541 
542 #define SECONDS		1
543 #define MINUTES		(SECONDS * 60)
544 #define HOURS		(MINUTES * 60)
545 #define DAYS		(HOURS * 24)
546 #define WEEKS		(DAYS * 7)
547 
548 /*
549  * Convert a time string into seconds; format is
550  * a sequence of:
551  *      time[qualifier]
552  *
553  * Valid time qualifiers are:
554  *      <none>  seconds
555  *      s|S     seconds
556  *      m|M     minutes
557  *      h|H     hours
558  *      d|D     days
559  *      w|W     weeks
560  *
561  * Examples:
562  *      90m     90 minutes
563  *      1h30m   90 minutes
564  *      2d      2 days
565  *      1w      1 week
566  *
567  * Return -1 if time string is invalid.
568  */
569 int
570 convtime(const char *s)
571 {
572 	long total, secs, multiplier;
573 	const char *p;
574 	char *endp;
575 
576 	errno = 0;
577 	total = 0;
578 	p = s;
579 
580 	if (p == NULL || *p == '\0')
581 		return -1;
582 
583 	while (*p) {
584 		secs = strtol(p, &endp, 10);
585 		if (p == endp ||
586 		    (errno == ERANGE && (secs == INT_MIN || secs == INT_MAX)) ||
587 		    secs < 0)
588 			return -1;
589 
590 		multiplier = 1;
591 		switch (*endp++) {
592 		case '\0':
593 			endp--;
594 			break;
595 		case 's':
596 		case 'S':
597 			break;
598 		case 'm':
599 		case 'M':
600 			multiplier = MINUTES;
601 			break;
602 		case 'h':
603 		case 'H':
604 			multiplier = HOURS;
605 			break;
606 		case 'd':
607 		case 'D':
608 			multiplier = DAYS;
609 			break;
610 		case 'w':
611 		case 'W':
612 			multiplier = WEEKS;
613 			break;
614 		default:
615 			return -1;
616 		}
617 		if (secs > INT_MAX / multiplier)
618 			return -1;
619 		secs *= multiplier;
620 		if  (total > INT_MAX - secs)
621 			return -1;
622 		total += secs;
623 		if (total < 0)
624 			return -1;
625 		p = endp;
626 	}
627 
628 	return total;
629 }
630 
631 #define TF_BUFS	8
632 #define TF_LEN	9
633 
634 const char *
635 fmt_timeframe(time_t t)
636 {
637 	char		*buf;
638 	static char	 tfbuf[TF_BUFS][TF_LEN];	/* ring buffer */
639 	static int	 idx = 0;
640 	unsigned int	 sec, min, hrs, day;
641 	unsigned long long	week;
642 
643 	buf = tfbuf[idx++];
644 	if (idx == TF_BUFS)
645 		idx = 0;
646 
647 	week = t;
648 
649 	sec = week % 60;
650 	week /= 60;
651 	min = week % 60;
652 	week /= 60;
653 	hrs = week % 24;
654 	week /= 24;
655 	day = week % 7;
656 	week /= 7;
657 
658 	if (week > 0)
659 		snprintf(buf, TF_LEN, "%02lluw%01ud%02uh", week, day, hrs);
660 	else if (day > 0)
661 		snprintf(buf, TF_LEN, "%01ud%02uh%02um", day, hrs, min);
662 	else
663 		snprintf(buf, TF_LEN, "%02u:%02u:%02u", hrs, min, sec);
664 
665 	return (buf);
666 }
667 
668 /*
669  * Returns a standardized host+port identifier string.
670  * Caller must free returned string.
671  */
672 char *
673 put_host_port(const char *host, u_short port)
674 {
675 	char *hoststr;
676 
677 	if (port == 0 || port == SSH_DEFAULT_PORT)
678 		return(xstrdup(host));
679 	if (asprintf(&hoststr, "[%s]:%d", host, (int)port) == -1)
680 		fatal("put_host_port: asprintf: %s", strerror(errno));
681 	debug3("put_host_port: %s", hoststr);
682 	return hoststr;
683 }
684 
685 /*
686  * Search for next delimiter between hostnames/addresses and ports.
687  * Argument may be modified (for termination).
688  * Returns *cp if parsing succeeds.
689  * *cp is set to the start of the next field, if one was found.
690  * The delimiter char, if present, is stored in delim.
691  * If this is the last field, *cp is set to NULL.
692  */
693 char *
694 hpdelim2(char **cp, char *delim)
695 {
696 	char *s, *old;
697 
698 	if (cp == NULL || *cp == NULL)
699 		return NULL;
700 
701 	old = s = *cp;
702 	if (*s == '[') {
703 		if ((s = strchr(s, ']')) == NULL)
704 			return NULL;
705 		else
706 			s++;
707 	} else if ((s = strpbrk(s, ":/")) == NULL)
708 		s = *cp + strlen(*cp); /* skip to end (see first case below) */
709 
710 	switch (*s) {
711 	case '\0':
712 		*cp = NULL;	/* no more fields*/
713 		break;
714 
715 	case ':':
716 	case '/':
717 		if (delim != NULL)
718 			*delim = *s;
719 		*s = '\0';	/* terminate */
720 		*cp = s + 1;
721 		break;
722 
723 	default:
724 		return NULL;
725 	}
726 
727 	return old;
728 }
729 
730 /* The common case: only accept colon as delimiter. */
731 char *
732 hpdelim(char **cp)
733 {
734 	char *r, delim = '\0';
735 
736 	r =  hpdelim2(cp, &delim);
737 	if (delim == '/')
738 		return NULL;
739 	return r;
740 }
741 
742 char *
743 cleanhostname(char *host)
744 {
745 	if (*host == '[' && host[strlen(host) - 1] == ']') {
746 		host[strlen(host) - 1] = '\0';
747 		return (host + 1);
748 	} else
749 		return host;
750 }
751 
752 char *
753 colon(char *cp)
754 {
755 	int flag = 0;
756 
757 	if (*cp == ':')		/* Leading colon is part of file name. */
758 		return NULL;
759 	if (*cp == '[')
760 		flag = 1;
761 
762 	for (; *cp; ++cp) {
763 		if (*cp == '@' && *(cp+1) == '[')
764 			flag = 1;
765 		if (*cp == ']' && *(cp+1) == ':' && flag)
766 			return (cp+1);
767 		if (*cp == ':' && !flag)
768 			return (cp);
769 		if (*cp == '/')
770 			return NULL;
771 	}
772 	return NULL;
773 }
774 
775 /*
776  * Parse a [user@]host:[path] string.
777  * Caller must free returned user, host and path.
778  * Any of the pointer return arguments may be NULL (useful for syntax checking).
779  * If user was not specified then *userp will be set to NULL.
780  * If host was not specified then *hostp will be set to NULL.
781  * If path was not specified then *pathp will be set to ".".
782  * Returns 0 on success, -1 on failure.
783  */
784 int
785 parse_user_host_path(const char *s, char **userp, char **hostp, char **pathp)
786 {
787 	char *user = NULL, *host = NULL, *path = NULL;
788 	char *sdup, *tmp;
789 	int ret = -1;
790 
791 	if (userp != NULL)
792 		*userp = NULL;
793 	if (hostp != NULL)
794 		*hostp = NULL;
795 	if (pathp != NULL)
796 		*pathp = NULL;
797 
798 	sdup = xstrdup(s);
799 
800 	/* Check for remote syntax: [user@]host:[path] */
801 	if ((tmp = colon(sdup)) == NULL)
802 		goto out;
803 
804 	/* Extract optional path */
805 	*tmp++ = '\0';
806 	if (*tmp == '\0')
807 		tmp = ".";
808 	path = xstrdup(tmp);
809 
810 	/* Extract optional user and mandatory host */
811 	tmp = strrchr(sdup, '@');
812 	if (tmp != NULL) {
813 		*tmp++ = '\0';
814 		host = xstrdup(cleanhostname(tmp));
815 		if (*sdup != '\0')
816 			user = xstrdup(sdup);
817 	} else {
818 		host = xstrdup(cleanhostname(sdup));
819 		user = NULL;
820 	}
821 
822 	/* Success */
823 	if (userp != NULL) {
824 		*userp = user;
825 		user = NULL;
826 	}
827 	if (hostp != NULL) {
828 		*hostp = host;
829 		host = NULL;
830 	}
831 	if (pathp != NULL) {
832 		*pathp = path;
833 		path = NULL;
834 	}
835 	ret = 0;
836 out:
837 	free(sdup);
838 	free(user);
839 	free(host);
840 	free(path);
841 	return ret;
842 }
843 
844 /*
845  * Parse a [user@]host[:port] string.
846  * Caller must free returned user and host.
847  * Any of the pointer return arguments may be NULL (useful for syntax checking).
848  * If user was not specified then *userp will be set to NULL.
849  * If port was not specified then *portp will be -1.
850  * Returns 0 on success, -1 on failure.
851  */
852 int
853 parse_user_host_port(const char *s, char **userp, char **hostp, int *portp)
854 {
855 	char *sdup, *cp, *tmp;
856 	char *user = NULL, *host = NULL;
857 	int port = -1, ret = -1;
858 
859 	if (userp != NULL)
860 		*userp = NULL;
861 	if (hostp != NULL)
862 		*hostp = NULL;
863 	if (portp != NULL)
864 		*portp = -1;
865 
866 	if ((sdup = tmp = strdup(s)) == NULL)
867 		return -1;
868 	/* Extract optional username */
869 	if ((cp = strrchr(tmp, '@')) != NULL) {
870 		*cp = '\0';
871 		if (*tmp == '\0')
872 			goto out;
873 		if ((user = strdup(tmp)) == NULL)
874 			goto out;
875 		tmp = cp + 1;
876 	}
877 	/* Extract mandatory hostname */
878 	if ((cp = hpdelim(&tmp)) == NULL || *cp == '\0')
879 		goto out;
880 	host = xstrdup(cleanhostname(cp));
881 	/* Convert and verify optional port */
882 	if (tmp != NULL && *tmp != '\0') {
883 		if ((port = a2port(tmp)) <= 0)
884 			goto out;
885 	}
886 	/* Success */
887 	if (userp != NULL) {
888 		*userp = user;
889 		user = NULL;
890 	}
891 	if (hostp != NULL) {
892 		*hostp = host;
893 		host = NULL;
894 	}
895 	if (portp != NULL)
896 		*portp = port;
897 	ret = 0;
898  out:
899 	free(sdup);
900 	free(user);
901 	free(host);
902 	return ret;
903 }
904 
905 /*
906  * Converts a two-byte hex string to decimal.
907  * Returns the decimal value or -1 for invalid input.
908  */
909 static int
910 hexchar(const char *s)
911 {
912 	unsigned char result[2];
913 	int i;
914 
915 	for (i = 0; i < 2; i++) {
916 		if (s[i] >= '0' && s[i] <= '9')
917 			result[i] = (unsigned char)(s[i] - '0');
918 		else if (s[i] >= 'a' && s[i] <= 'f')
919 			result[i] = (unsigned char)(s[i] - 'a') + 10;
920 		else if (s[i] >= 'A' && s[i] <= 'F')
921 			result[i] = (unsigned char)(s[i] - 'A') + 10;
922 		else
923 			return -1;
924 	}
925 	return (result[0] << 4) | result[1];
926 }
927 
928 /*
929  * Decode an url-encoded string.
930  * Returns a newly allocated string on success or NULL on failure.
931  */
932 static char *
933 urldecode(const char *src)
934 {
935 	char *ret, *dst;
936 	int ch;
937 	size_t srclen;
938 
939 	if ((srclen = strlen(src)) >= SIZE_MAX)
940 		fatal_f("input too large");
941 	ret = xmalloc(srclen + 1);
942 	for (dst = ret; *src != '\0'; src++) {
943 		switch (*src) {
944 		case '+':
945 			*dst++ = ' ';
946 			break;
947 		case '%':
948 			if (!isxdigit((unsigned char)src[1]) ||
949 			    !isxdigit((unsigned char)src[2]) ||
950 			    (ch = hexchar(src + 1)) == -1) {
951 				free(ret);
952 				return NULL;
953 			}
954 			*dst++ = ch;
955 			src += 2;
956 			break;
957 		default:
958 			*dst++ = *src;
959 			break;
960 		}
961 	}
962 	*dst = '\0';
963 
964 	return ret;
965 }
966 
967 /*
968  * Parse an (scp|ssh|sftp)://[user@]host[:port][/path] URI.
969  * See https://tools.ietf.org/html/draft-ietf-secsh-scp-sftp-ssh-uri-04
970  * Either user or path may be url-encoded (but not host or port).
971  * Caller must free returned user, host and path.
972  * Any of the pointer return arguments may be NULL (useful for syntax checking)
973  * but the scheme must always be specified.
974  * If user was not specified then *userp will be set to NULL.
975  * If port was not specified then *portp will be -1.
976  * If path was not specified then *pathp will be set to NULL.
977  * Returns 0 on success, 1 if non-uri/wrong scheme, -1 on error/invalid uri.
978  */
979 int
980 parse_uri(const char *scheme, const char *uri, char **userp, char **hostp,
981     int *portp, char **pathp)
982 {
983 	char *uridup, *cp, *tmp, ch;
984 	char *user = NULL, *host = NULL, *path = NULL;
985 	int port = -1, ret = -1;
986 	size_t len;
987 
988 	len = strlen(scheme);
989 	if (strncmp(uri, scheme, len) != 0 || strncmp(uri + len, "://", 3) != 0)
990 		return 1;
991 	uri += len + 3;
992 
993 	if (userp != NULL)
994 		*userp = NULL;
995 	if (hostp != NULL)
996 		*hostp = NULL;
997 	if (portp != NULL)
998 		*portp = -1;
999 	if (pathp != NULL)
1000 		*pathp = NULL;
1001 
1002 	uridup = tmp = xstrdup(uri);
1003 
1004 	/* Extract optional ssh-info (username + connection params) */
1005 	if ((cp = strchr(tmp, '@')) != NULL) {
1006 		char *delim;
1007 
1008 		*cp = '\0';
1009 		/* Extract username and connection params */
1010 		if ((delim = strchr(tmp, ';')) != NULL) {
1011 			/* Just ignore connection params for now */
1012 			*delim = '\0';
1013 		}
1014 		if (*tmp == '\0') {
1015 			/* Empty username */
1016 			goto out;
1017 		}
1018 		if ((user = urldecode(tmp)) == NULL)
1019 			goto out;
1020 		tmp = cp + 1;
1021 	}
1022 
1023 	/* Extract mandatory hostname */
1024 	if ((cp = hpdelim2(&tmp, &ch)) == NULL || *cp == '\0')
1025 		goto out;
1026 	host = xstrdup(cleanhostname(cp));
1027 	if (!valid_domain(host, 0, NULL))
1028 		goto out;
1029 
1030 	if (tmp != NULL && *tmp != '\0') {
1031 		if (ch == ':') {
1032 			/* Convert and verify port. */
1033 			if ((cp = strchr(tmp, '/')) != NULL)
1034 				*cp = '\0';
1035 			if ((port = a2port(tmp)) <= 0)
1036 				goto out;
1037 			tmp = cp ? cp + 1 : NULL;
1038 		}
1039 		if (tmp != NULL && *tmp != '\0') {
1040 			/* Extract optional path */
1041 			if ((path = urldecode(tmp)) == NULL)
1042 				goto out;
1043 		}
1044 	}
1045 
1046 	/* Success */
1047 	if (userp != NULL) {
1048 		*userp = user;
1049 		user = NULL;
1050 	}
1051 	if (hostp != NULL) {
1052 		*hostp = host;
1053 		host = NULL;
1054 	}
1055 	if (portp != NULL)
1056 		*portp = port;
1057 	if (pathp != NULL) {
1058 		*pathp = path;
1059 		path = NULL;
1060 	}
1061 	ret = 0;
1062  out:
1063 	free(uridup);
1064 	free(user);
1065 	free(host);
1066 	free(path);
1067 	return ret;
1068 }
1069 
1070 /* function to assist building execv() arguments */
1071 void
1072 addargs(arglist *args, char *fmt, ...)
1073 {
1074 	va_list ap;
1075 	char *cp;
1076 	u_int nalloc;
1077 	int r;
1078 
1079 	va_start(ap, fmt);
1080 	r = vasprintf(&cp, fmt, ap);
1081 	va_end(ap);
1082 	if (r == -1)
1083 		fatal_f("argument too long");
1084 
1085 	nalloc = args->nalloc;
1086 	if (args->list == NULL) {
1087 		nalloc = 32;
1088 		args->num = 0;
1089 	} else if (args->num > (256 * 1024))
1090 		fatal_f("too many arguments");
1091 	else if (args->num >= args->nalloc)
1092 		fatal_f("arglist corrupt");
1093 	else if (args->num+2 >= nalloc)
1094 		nalloc *= 2;
1095 
1096 	args->list = xrecallocarray(args->list, args->nalloc,
1097 	    nalloc, sizeof(char *));
1098 	args->nalloc = nalloc;
1099 	args->list[args->num++] = cp;
1100 	args->list[args->num] = NULL;
1101 }
1102 
1103 void
1104 replacearg(arglist *args, u_int which, char *fmt, ...)
1105 {
1106 	va_list ap;
1107 	char *cp;
1108 	int r;
1109 
1110 	va_start(ap, fmt);
1111 	r = vasprintf(&cp, fmt, ap);
1112 	va_end(ap);
1113 	if (r == -1)
1114 		fatal_f("argument too long");
1115 	if (args->list == NULL || args->num >= args->nalloc)
1116 		fatal_f("arglist corrupt");
1117 
1118 	if (which >= args->num)
1119 		fatal_f("tried to replace invalid arg %d >= %d",
1120 		    which, args->num);
1121 	free(args->list[which]);
1122 	args->list[which] = cp;
1123 }
1124 
1125 void
1126 freeargs(arglist *args)
1127 {
1128 	u_int i;
1129 
1130 	if (args == NULL)
1131 		return;
1132 	if (args->list != NULL && args->num < args->nalloc) {
1133 		for (i = 0; i < args->num; i++)
1134 			free(args->list[i]);
1135 		free(args->list);
1136 	}
1137 	args->nalloc = args->num = 0;
1138 	args->list = NULL;
1139 }
1140 
1141 /*
1142  * Expands tildes in the file name.  Returns data allocated by xmalloc.
1143  * Warning: this calls getpw*.
1144  */
1145 int
1146 tilde_expand(const char *filename, uid_t uid, char **retp)
1147 {
1148 	char *ocopy = NULL, *copy, *s = NULL;
1149 	const char *path = NULL, *user = NULL;
1150 	struct passwd *pw;
1151 	size_t len;
1152 	int ret = -1, r, slash;
1153 
1154 	*retp = NULL;
1155 	if (*filename != '~') {
1156 		*retp = xstrdup(filename);
1157 		return 0;
1158 	}
1159 	ocopy = copy = xstrdup(filename + 1);
1160 
1161 	if (*copy == '\0')				/* ~ */
1162 		path = NULL;
1163 	else if (*copy == '/') {
1164 		copy += strspn(copy, "/");
1165 		if (*copy == '\0')
1166 			path = NULL;			/* ~/ */
1167 		else
1168 			path = copy;			/* ~/path */
1169 	} else {
1170 		user = copy;
1171 		if ((path = strchr(copy, '/')) != NULL) {
1172 			copy[path - copy] = '\0';
1173 			path++;
1174 			path += strspn(path, "/");
1175 			if (*path == '\0')		/* ~user/ */
1176 				path = NULL;
1177 			/* else				 ~user/path */
1178 		}
1179 		/* else					~user */
1180 	}
1181 	if (user != NULL) {
1182 		if ((pw = getpwnam(user)) == NULL) {
1183 			error_f("No such user %s", user);
1184 			goto out;
1185 		}
1186 	} else if ((pw = getpwuid(uid)) == NULL) {
1187 		error_f("No such uid %ld", (long)uid);
1188 		goto out;
1189 	}
1190 
1191 	/* Make sure directory has a trailing '/' */
1192 	slash = (len = strlen(pw->pw_dir)) == 0 || pw->pw_dir[len - 1] != '/';
1193 
1194 	if ((r = xasprintf(&s, "%s%s%s", pw->pw_dir,
1195 	    slash ? "/" : "", path != NULL ? path : "")) <= 0) {
1196 		error_f("xasprintf failed");
1197 		goto out;
1198 	}
1199 	if (r >= PATH_MAX) {
1200 		error_f("Path too long");
1201 		goto out;
1202 	}
1203 	/* success */
1204 	ret = 0;
1205 	*retp = s;
1206 	s = NULL;
1207  out:
1208 	free(s);
1209 	free(ocopy);
1210 	return ret;
1211 }
1212 
1213 char *
1214 tilde_expand_filename(const char *filename, uid_t uid)
1215 {
1216 	char *ret;
1217 
1218 	if (tilde_expand(filename, uid, &ret) != 0)
1219 		cleanup_exit(255);
1220 	return ret;
1221 }
1222 
1223 /*
1224  * Expand a string with a set of %[char] escapes and/or ${ENVIRONMENT}
1225  * substitutions.  A number of escapes may be specified as
1226  * (char *escape_chars, char *replacement) pairs. The list must be terminated
1227  * by a NULL escape_char. Returns replaced string in memory allocated by
1228  * xmalloc which the caller must free.
1229  */
1230 static char *
1231 vdollar_percent_expand(int *parseerror, int dollar, int percent,
1232     const char *string, va_list ap)
1233 {
1234 #define EXPAND_MAX_KEYS	16
1235 	u_int num_keys = 0, i;
1236 	struct {
1237 		const char *key;
1238 		const char *repl;
1239 	} keys[EXPAND_MAX_KEYS];
1240 	struct sshbuf *buf;
1241 	int r, missingvar = 0;
1242 	char *ret = NULL, *var, *varend, *val;
1243 	size_t len;
1244 
1245 	if ((buf = sshbuf_new()) == NULL)
1246 		fatal_f("sshbuf_new failed");
1247 	if (parseerror == NULL)
1248 		fatal_f("null parseerror arg");
1249 	*parseerror = 1;
1250 
1251 	/* Gather keys if we're doing percent expansion. */
1252 	if (percent) {
1253 		for (num_keys = 0; num_keys < EXPAND_MAX_KEYS; num_keys++) {
1254 			keys[num_keys].key = va_arg(ap, char *);
1255 			if (keys[num_keys].key == NULL)
1256 				break;
1257 			keys[num_keys].repl = va_arg(ap, char *);
1258 			if (keys[num_keys].repl == NULL) {
1259 				fatal_f("NULL replacement for token %s",
1260 				    keys[num_keys].key);
1261 			}
1262 		}
1263 		if (num_keys == EXPAND_MAX_KEYS && va_arg(ap, char *) != NULL)
1264 			fatal_f("too many keys");
1265 		if (num_keys == 0)
1266 			fatal_f("percent expansion without token list");
1267 	}
1268 
1269 	/* Expand string */
1270 	for (i = 0; *string != '\0'; string++) {
1271 		/* Optionally process ${ENVIRONMENT} expansions. */
1272 		if (dollar && string[0] == '$' && string[1] == '{') {
1273 			string += 2;  /* skip over '${' */
1274 			if ((varend = strchr(string, '}')) == NULL) {
1275 				error_f("environment variable '%s' missing "
1276 				    "closing '}'", string);
1277 				goto out;
1278 			}
1279 			len = varend - string;
1280 			if (len == 0) {
1281 				error_f("zero-length environment variable");
1282 				goto out;
1283 			}
1284 			var = xmalloc(len + 1);
1285 			(void)strlcpy(var, string, len + 1);
1286 			if ((val = getenv(var)) == NULL) {
1287 				error_f("env var ${%s} has no value", var);
1288 				missingvar = 1;
1289 			} else {
1290 				debug3_f("expand ${%s} -> '%s'", var, val);
1291 				if ((r = sshbuf_put(buf, val, strlen(val))) !=0)
1292 					fatal_fr(r, "sshbuf_put ${}");
1293 			}
1294 			free(var);
1295 			string += len;
1296 			continue;
1297 		}
1298 
1299 		/*
1300 		 * Process percent expansions if we have a list of TOKENs.
1301 		 * If we're not doing percent expansion everything just gets
1302 		 * appended here.
1303 		 */
1304 		if (*string != '%' || !percent) {
1305  append:
1306 			if ((r = sshbuf_put_u8(buf, *string)) != 0)
1307 				fatal_fr(r, "sshbuf_put_u8 %%");
1308 			continue;
1309 		}
1310 		string++;
1311 		/* %% case */
1312 		if (*string == '%')
1313 			goto append;
1314 		if (*string == '\0') {
1315 			error_f("invalid format");
1316 			goto out;
1317 		}
1318 		for (i = 0; i < num_keys; i++) {
1319 			if (strchr(keys[i].key, *string) != NULL) {
1320 				if ((r = sshbuf_put(buf, keys[i].repl,
1321 				    strlen(keys[i].repl))) != 0)
1322 					fatal_fr(r, "sshbuf_put %%-repl");
1323 				break;
1324 			}
1325 		}
1326 		if (i >= num_keys) {
1327 			error_f("unknown key %%%c", *string);
1328 			goto out;
1329 		}
1330 	}
1331 	if (!missingvar && (ret = sshbuf_dup_string(buf)) == NULL)
1332 		fatal_f("sshbuf_dup_string failed");
1333 	*parseerror = 0;
1334  out:
1335 	sshbuf_free(buf);
1336 	return *parseerror ? NULL : ret;
1337 #undef EXPAND_MAX_KEYS
1338 }
1339 
1340 /*
1341  * Expand only environment variables.
1342  * Note that although this function is variadic like the other similar
1343  * functions, any such arguments will be unused.
1344  */
1345 
1346 char *
1347 dollar_expand(int *parseerr, const char *string, ...)
1348 {
1349 	char *ret;
1350 	int err;
1351 	va_list ap;
1352 
1353 	va_start(ap, string);
1354 	ret = vdollar_percent_expand(&err, 1, 0, string, ap);
1355 	va_end(ap);
1356 	if (parseerr != NULL)
1357 		*parseerr = err;
1358 	return ret;
1359 }
1360 
1361 /*
1362  * Returns expanded string or NULL if a specified environment variable is
1363  * not defined, or calls fatal if the string is invalid.
1364  */
1365 char *
1366 percent_expand(const char *string, ...)
1367 {
1368 	char *ret;
1369 	int err;
1370 	va_list ap;
1371 
1372 	va_start(ap, string);
1373 	ret = vdollar_percent_expand(&err, 0, 1, string, ap);
1374 	va_end(ap);
1375 	if (err)
1376 		fatal_f("failed");
1377 	return ret;
1378 }
1379 
1380 /*
1381  * Returns expanded string or NULL if a specified environment variable is
1382  * not defined, or calls fatal if the string is invalid.
1383  */
1384 char *
1385 percent_dollar_expand(const char *string, ...)
1386 {
1387 	char *ret;
1388 	int err;
1389 	va_list ap;
1390 
1391 	va_start(ap, string);
1392 	ret = vdollar_percent_expand(&err, 1, 1, string, ap);
1393 	va_end(ap);
1394 	if (err)
1395 		fatal_f("failed");
1396 	return ret;
1397 }
1398 
1399 int
1400 tun_open(int tun, int mode, char **ifname)
1401 {
1402 #if defined(CUSTOM_SYS_TUN_OPEN)
1403 	return (sys_tun_open(tun, mode, ifname));
1404 #elif defined(SSH_TUN_OPENBSD)
1405 	struct ifreq ifr;
1406 	char name[100];
1407 	int fd = -1, sock;
1408 	const char *tunbase = "tun";
1409 
1410 	if (ifname != NULL)
1411 		*ifname = NULL;
1412 
1413 	if (mode == SSH_TUNMODE_ETHERNET)
1414 		tunbase = "tap";
1415 
1416 	/* Open the tunnel device */
1417 	if (tun <= SSH_TUNID_MAX) {
1418 		snprintf(name, sizeof(name), "/dev/%s%d", tunbase, tun);
1419 		fd = open(name, O_RDWR);
1420 	} else if (tun == SSH_TUNID_ANY) {
1421 		for (tun = 100; tun >= 0; tun--) {
1422 			snprintf(name, sizeof(name), "/dev/%s%d",
1423 			    tunbase, tun);
1424 			if ((fd = open(name, O_RDWR)) >= 0)
1425 				break;
1426 		}
1427 	} else {
1428 		debug_f("invalid tunnel %u", tun);
1429 		return -1;
1430 	}
1431 
1432 	if (fd == -1) {
1433 		debug_f("%s open: %s", name, strerror(errno));
1434 		return -1;
1435 	}
1436 
1437 	debug_f("%s mode %d fd %d", name, mode, fd);
1438 
1439 	/* Bring interface up if it is not already */
1440 	snprintf(ifr.ifr_name, sizeof(ifr.ifr_name), "%s%d", tunbase, tun);
1441 	if ((sock = socket(PF_UNIX, SOCK_STREAM, 0)) == -1)
1442 		goto failed;
1443 
1444 	if (ioctl(sock, SIOCGIFFLAGS, &ifr) == -1) {
1445 		debug_f("get interface %s flags: %s", ifr.ifr_name,
1446 		    strerror(errno));
1447 		goto failed;
1448 	}
1449 
1450 	if (!(ifr.ifr_flags & IFF_UP)) {
1451 		ifr.ifr_flags |= IFF_UP;
1452 		if (ioctl(sock, SIOCSIFFLAGS, &ifr) == -1) {
1453 			debug_f("activate interface %s: %s", ifr.ifr_name,
1454 			    strerror(errno));
1455 			goto failed;
1456 		}
1457 	}
1458 
1459 	if (ifname != NULL)
1460 		*ifname = xstrdup(ifr.ifr_name);
1461 
1462 	close(sock);
1463 	return fd;
1464 
1465  failed:
1466 	if (fd >= 0)
1467 		close(fd);
1468 	if (sock >= 0)
1469 		close(sock);
1470 	return -1;
1471 #else
1472 	error("Tunnel interfaces are not supported on this platform");
1473 	return (-1);
1474 #endif
1475 }
1476 
1477 void
1478 sanitise_stdfd(void)
1479 {
1480 	int nullfd, dupfd;
1481 
1482 	if ((nullfd = dupfd = open(_PATH_DEVNULL, O_RDWR)) == -1) {
1483 		fprintf(stderr, "Couldn't open /dev/null: %s\n",
1484 		    strerror(errno));
1485 		exit(1);
1486 	}
1487 	while (++dupfd <= STDERR_FILENO) {
1488 		/* Only populate closed fds. */
1489 		if (fcntl(dupfd, F_GETFL) == -1 && errno == EBADF) {
1490 			if (dup2(nullfd, dupfd) == -1) {
1491 				fprintf(stderr, "dup2: %s\n", strerror(errno));
1492 				exit(1);
1493 			}
1494 		}
1495 	}
1496 	if (nullfd > STDERR_FILENO)
1497 		close(nullfd);
1498 }
1499 
1500 char *
1501 tohex(const void *vp, size_t l)
1502 {
1503 	const u_char *p = (const u_char *)vp;
1504 	char b[3], *r;
1505 	size_t i, hl;
1506 
1507 	if (l > 65536)
1508 		return xstrdup("tohex: length > 65536");
1509 
1510 	hl = l * 2 + 1;
1511 	r = xcalloc(1, hl);
1512 	for (i = 0; i < l; i++) {
1513 		snprintf(b, sizeof(b), "%02x", p[i]);
1514 		strlcat(r, b, hl);
1515 	}
1516 	return (r);
1517 }
1518 
1519 /*
1520  * Extend string *sp by the specified format. If *sp is not NULL (or empty),
1521  * then the separator 'sep' will be prepended before the formatted arguments.
1522  * Extended strings are heap allocated.
1523  */
1524 void
1525 xextendf(char **sp, const char *sep, const char *fmt, ...)
1526 {
1527 	va_list ap;
1528 	char *tmp1, *tmp2;
1529 
1530 	va_start(ap, fmt);
1531 	xvasprintf(&tmp1, fmt, ap);
1532 	va_end(ap);
1533 
1534 	if (*sp == NULL || **sp == '\0') {
1535 		free(*sp);
1536 		*sp = tmp1;
1537 		return;
1538 	}
1539 	xasprintf(&tmp2, "%s%s%s", *sp, sep == NULL ? "" : sep, tmp1);
1540 	free(tmp1);
1541 	free(*sp);
1542 	*sp = tmp2;
1543 }
1544 
1545 
1546 u_int64_t
1547 get_u64(const void *vp)
1548 {
1549 	const u_char *p = (const u_char *)vp;
1550 	u_int64_t v;
1551 
1552 	v  = (u_int64_t)p[0] << 56;
1553 	v |= (u_int64_t)p[1] << 48;
1554 	v |= (u_int64_t)p[2] << 40;
1555 	v |= (u_int64_t)p[3] << 32;
1556 	v |= (u_int64_t)p[4] << 24;
1557 	v |= (u_int64_t)p[5] << 16;
1558 	v |= (u_int64_t)p[6] << 8;
1559 	v |= (u_int64_t)p[7];
1560 
1561 	return (v);
1562 }
1563 
1564 u_int32_t
1565 get_u32(const void *vp)
1566 {
1567 	const u_char *p = (const u_char *)vp;
1568 	u_int32_t v;
1569 
1570 	v  = (u_int32_t)p[0] << 24;
1571 	v |= (u_int32_t)p[1] << 16;
1572 	v |= (u_int32_t)p[2] << 8;
1573 	v |= (u_int32_t)p[3];
1574 
1575 	return (v);
1576 }
1577 
1578 u_int32_t
1579 get_u32_le(const void *vp)
1580 {
1581 	const u_char *p = (const u_char *)vp;
1582 	u_int32_t v;
1583 
1584 	v  = (u_int32_t)p[0];
1585 	v |= (u_int32_t)p[1] << 8;
1586 	v |= (u_int32_t)p[2] << 16;
1587 	v |= (u_int32_t)p[3] << 24;
1588 
1589 	return (v);
1590 }
1591 
1592 u_int16_t
1593 get_u16(const void *vp)
1594 {
1595 	const u_char *p = (const u_char *)vp;
1596 	u_int16_t v;
1597 
1598 	v  = (u_int16_t)p[0] << 8;
1599 	v |= (u_int16_t)p[1];
1600 
1601 	return (v);
1602 }
1603 
1604 void
1605 put_u64(void *vp, u_int64_t v)
1606 {
1607 	u_char *p = (u_char *)vp;
1608 
1609 	p[0] = (u_char)(v >> 56) & 0xff;
1610 	p[1] = (u_char)(v >> 48) & 0xff;
1611 	p[2] = (u_char)(v >> 40) & 0xff;
1612 	p[3] = (u_char)(v >> 32) & 0xff;
1613 	p[4] = (u_char)(v >> 24) & 0xff;
1614 	p[5] = (u_char)(v >> 16) & 0xff;
1615 	p[6] = (u_char)(v >> 8) & 0xff;
1616 	p[7] = (u_char)v & 0xff;
1617 }
1618 
1619 void
1620 put_u32(void *vp, u_int32_t v)
1621 {
1622 	u_char *p = (u_char *)vp;
1623 
1624 	p[0] = (u_char)(v >> 24) & 0xff;
1625 	p[1] = (u_char)(v >> 16) & 0xff;
1626 	p[2] = (u_char)(v >> 8) & 0xff;
1627 	p[3] = (u_char)v & 0xff;
1628 }
1629 
1630 void
1631 put_u32_le(void *vp, u_int32_t v)
1632 {
1633 	u_char *p = (u_char *)vp;
1634 
1635 	p[0] = (u_char)v & 0xff;
1636 	p[1] = (u_char)(v >> 8) & 0xff;
1637 	p[2] = (u_char)(v >> 16) & 0xff;
1638 	p[3] = (u_char)(v >> 24) & 0xff;
1639 }
1640 
1641 void
1642 put_u16(void *vp, u_int16_t v)
1643 {
1644 	u_char *p = (u_char *)vp;
1645 
1646 	p[0] = (u_char)(v >> 8) & 0xff;
1647 	p[1] = (u_char)v & 0xff;
1648 }
1649 
1650 void
1651 ms_subtract_diff(struct timeval *start, int *ms)
1652 {
1653 	struct timeval diff, finish;
1654 
1655 	monotime_tv(&finish);
1656 	timersub(&finish, start, &diff);
1657 	*ms -= (diff.tv_sec * 1000) + (diff.tv_usec / 1000);
1658 }
1659 
1660 void
1661 ms_to_timespec(struct timespec *ts, int ms)
1662 {
1663 	if (ms < 0)
1664 		ms = 0;
1665 	ts->tv_sec = ms / 1000;
1666 	ts->tv_nsec = (ms % 1000) * 1000 * 1000;
1667 }
1668 
1669 void
1670 monotime_ts(struct timespec *ts)
1671 {
1672 	struct timeval tv;
1673 #if defined(HAVE_CLOCK_GETTIME) && (defined(CLOCK_BOOTTIME) || \
1674     defined(CLOCK_MONOTONIC) || defined(CLOCK_REALTIME))
1675 	static int gettime_failed = 0;
1676 
1677 	if (!gettime_failed) {
1678 # ifdef CLOCK_BOOTTIME
1679 		if (clock_gettime(CLOCK_BOOTTIME, ts) == 0)
1680 			return;
1681 # endif /* CLOCK_BOOTTIME */
1682 # ifdef CLOCK_MONOTONIC
1683 		if (clock_gettime(CLOCK_MONOTONIC, ts) == 0)
1684 			return;
1685 # endif /* CLOCK_MONOTONIC */
1686 # ifdef CLOCK_REALTIME
1687 		/* Not monotonic, but we're almost out of options here. */
1688 		if (clock_gettime(CLOCK_REALTIME, ts) == 0)
1689 			return;
1690 # endif /* CLOCK_REALTIME */
1691 		debug3("clock_gettime: %s", strerror(errno));
1692 		gettime_failed = 1;
1693 	}
1694 #endif /* HAVE_CLOCK_GETTIME && (BOOTTIME || MONOTONIC || REALTIME) */
1695 	gettimeofday(&tv, NULL);
1696 	ts->tv_sec = tv.tv_sec;
1697 	ts->tv_nsec = (long)tv.tv_usec * 1000;
1698 }
1699 
1700 void
1701 monotime_tv(struct timeval *tv)
1702 {
1703 	struct timespec ts;
1704 
1705 	monotime_ts(&ts);
1706 	tv->tv_sec = ts.tv_sec;
1707 	tv->tv_usec = ts.tv_nsec / 1000;
1708 }
1709 
1710 time_t
1711 monotime(void)
1712 {
1713 	struct timespec ts;
1714 
1715 	monotime_ts(&ts);
1716 	return ts.tv_sec;
1717 }
1718 
1719 double
1720 monotime_double(void)
1721 {
1722 	struct timespec ts;
1723 
1724 	monotime_ts(&ts);
1725 	return ts.tv_sec + ((double)ts.tv_nsec / 1000000000);
1726 }
1727 
1728 void
1729 bandwidth_limit_init(struct bwlimit *bw, u_int64_t kbps, size_t buflen)
1730 {
1731 	bw->buflen = buflen;
1732 	bw->rate = kbps;
1733 	bw->thresh = buflen;
1734 	bw->lamt = 0;
1735 	timerclear(&bw->bwstart);
1736 	timerclear(&bw->bwend);
1737 }
1738 
1739 /* Callback from read/write loop to insert bandwidth-limiting delays */
1740 void
1741 bandwidth_limit(struct bwlimit *bw, size_t read_len)
1742 {
1743 	u_int64_t waitlen;
1744 	struct timespec ts, rm;
1745 
1746 	bw->lamt += read_len;
1747 	if (!timerisset(&bw->bwstart)) {
1748 		monotime_tv(&bw->bwstart);
1749 		return;
1750 	}
1751 	if (bw->lamt < bw->thresh)
1752 		return;
1753 
1754 	monotime_tv(&bw->bwend);
1755 	timersub(&bw->bwend, &bw->bwstart, &bw->bwend);
1756 	if (!timerisset(&bw->bwend))
1757 		return;
1758 
1759 	bw->lamt *= 8;
1760 	waitlen = (double)1000000L * bw->lamt / bw->rate;
1761 
1762 	bw->bwstart.tv_sec = waitlen / 1000000L;
1763 	bw->bwstart.tv_usec = waitlen % 1000000L;
1764 
1765 	if (timercmp(&bw->bwstart, &bw->bwend, >)) {
1766 		timersub(&bw->bwstart, &bw->bwend, &bw->bwend);
1767 
1768 		/* Adjust the wait time */
1769 		if (bw->bwend.tv_sec) {
1770 			bw->thresh /= 2;
1771 			if (bw->thresh < bw->buflen / 4)
1772 				bw->thresh = bw->buflen / 4;
1773 		} else if (bw->bwend.tv_usec < 10000) {
1774 			bw->thresh *= 2;
1775 			if (bw->thresh > bw->buflen * 8)
1776 				bw->thresh = bw->buflen * 8;
1777 		}
1778 
1779 		TIMEVAL_TO_TIMESPEC(&bw->bwend, &ts);
1780 		while (nanosleep(&ts, &rm) == -1) {
1781 			if (errno != EINTR)
1782 				break;
1783 			ts = rm;
1784 		}
1785 	}
1786 
1787 	bw->lamt = 0;
1788 	monotime_tv(&bw->bwstart);
1789 }
1790 
1791 /* Make a template filename for mk[sd]temp() */
1792 void
1793 mktemp_proto(char *s, size_t len)
1794 {
1795 	const char *tmpdir;
1796 	int r;
1797 
1798 	if ((tmpdir = getenv("TMPDIR")) != NULL) {
1799 		r = snprintf(s, len, "%s/ssh-XXXXXXXXXXXX", tmpdir);
1800 		if (r > 0 && (size_t)r < len)
1801 			return;
1802 	}
1803 	r = snprintf(s, len, "/tmp/ssh-XXXXXXXXXXXX");
1804 	if (r < 0 || (size_t)r >= len)
1805 		fatal_f("template string too short");
1806 }
1807 
1808 static const struct {
1809 	const char *name;
1810 	int value;
1811 } ipqos[] = {
1812 	{ "none", INT_MAX },		/* can't use 0 here; that's CS0 */
1813 	{ "af11", IPTOS_DSCP_AF11 },
1814 	{ "af12", IPTOS_DSCP_AF12 },
1815 	{ "af13", IPTOS_DSCP_AF13 },
1816 	{ "af21", IPTOS_DSCP_AF21 },
1817 	{ "af22", IPTOS_DSCP_AF22 },
1818 	{ "af23", IPTOS_DSCP_AF23 },
1819 	{ "af31", IPTOS_DSCP_AF31 },
1820 	{ "af32", IPTOS_DSCP_AF32 },
1821 	{ "af33", IPTOS_DSCP_AF33 },
1822 	{ "af41", IPTOS_DSCP_AF41 },
1823 	{ "af42", IPTOS_DSCP_AF42 },
1824 	{ "af43", IPTOS_DSCP_AF43 },
1825 	{ "cs0", IPTOS_DSCP_CS0 },
1826 	{ "cs1", IPTOS_DSCP_CS1 },
1827 	{ "cs2", IPTOS_DSCP_CS2 },
1828 	{ "cs3", IPTOS_DSCP_CS3 },
1829 	{ "cs4", IPTOS_DSCP_CS4 },
1830 	{ "cs5", IPTOS_DSCP_CS5 },
1831 	{ "cs6", IPTOS_DSCP_CS6 },
1832 	{ "cs7", IPTOS_DSCP_CS7 },
1833 	{ "ef", IPTOS_DSCP_EF },
1834 	{ "le", IPTOS_DSCP_LE },
1835 	{ "lowdelay", IPTOS_LOWDELAY },
1836 	{ "throughput", IPTOS_THROUGHPUT },
1837 	{ "reliability", IPTOS_RELIABILITY },
1838 	{ NULL, -1 }
1839 };
1840 
1841 int
1842 parse_ipqos(const char *cp)
1843 {
1844 	u_int i;
1845 	char *ep;
1846 	long val;
1847 
1848 	if (cp == NULL)
1849 		return -1;
1850 	for (i = 0; ipqos[i].name != NULL; i++) {
1851 		if (strcasecmp(cp, ipqos[i].name) == 0)
1852 			return ipqos[i].value;
1853 	}
1854 	/* Try parsing as an integer */
1855 	val = strtol(cp, &ep, 0);
1856 	if (*cp == '\0' || *ep != '\0' || val < 0 || val > 255)
1857 		return -1;
1858 	return val;
1859 }
1860 
1861 const char *
1862 iptos2str(int iptos)
1863 {
1864 	int i;
1865 	static char iptos_str[sizeof "0xff"];
1866 
1867 	for (i = 0; ipqos[i].name != NULL; i++) {
1868 		if (ipqos[i].value == iptos)
1869 			return ipqos[i].name;
1870 	}
1871 	snprintf(iptos_str, sizeof iptos_str, "0x%02x", iptos);
1872 	return iptos_str;
1873 }
1874 
1875 void
1876 lowercase(char *s)
1877 {
1878 	for (; *s; s++)
1879 		*s = tolower((u_char)*s);
1880 }
1881 
1882 int
1883 unix_listener(const char *path, int backlog, int unlink_first)
1884 {
1885 	struct sockaddr_un sunaddr;
1886 	int saved_errno, sock;
1887 
1888 	memset(&sunaddr, 0, sizeof(sunaddr));
1889 	sunaddr.sun_family = AF_UNIX;
1890 	if (strlcpy(sunaddr.sun_path, path,
1891 	    sizeof(sunaddr.sun_path)) >= sizeof(sunaddr.sun_path)) {
1892 		error_f("path \"%s\" too long for Unix domain socket", path);
1893 		errno = ENAMETOOLONG;
1894 		return -1;
1895 	}
1896 
1897 	sock = socket(PF_UNIX, SOCK_STREAM, 0);
1898 	if (sock == -1) {
1899 		saved_errno = errno;
1900 		error_f("socket: %.100s", strerror(errno));
1901 		errno = saved_errno;
1902 		return -1;
1903 	}
1904 	if (unlink_first == 1) {
1905 		if (unlink(path) != 0 && errno != ENOENT)
1906 			error("unlink(%s): %.100s", path, strerror(errno));
1907 	}
1908 	if (bind(sock, (struct sockaddr *)&sunaddr, sizeof(sunaddr)) == -1) {
1909 		saved_errno = errno;
1910 		error_f("cannot bind to path %s: %s", path, strerror(errno));
1911 		close(sock);
1912 		errno = saved_errno;
1913 		return -1;
1914 	}
1915 	if (listen(sock, backlog) == -1) {
1916 		saved_errno = errno;
1917 		error_f("cannot listen on path %s: %s", path, strerror(errno));
1918 		close(sock);
1919 		unlink(path);
1920 		errno = saved_errno;
1921 		return -1;
1922 	}
1923 	return sock;
1924 }
1925 
1926 void
1927 sock_set_v6only(int s)
1928 {
1929 #if defined(IPV6_V6ONLY) && !defined(__OpenBSD__)
1930 	int on = 1;
1931 
1932 	debug3("%s: set socket %d IPV6_V6ONLY", __func__, s);
1933 	if (setsockopt(s, IPPROTO_IPV6, IPV6_V6ONLY, &on, sizeof(on)) == -1)
1934 		error("setsockopt IPV6_V6ONLY: %s", strerror(errno));
1935 #endif
1936 }
1937 
1938 /*
1939  * Compares two strings that maybe be NULL. Returns non-zero if strings
1940  * are both NULL or are identical, returns zero otherwise.
1941  */
1942 static int
1943 strcmp_maybe_null(const char *a, const char *b)
1944 {
1945 	if ((a == NULL && b != NULL) || (a != NULL && b == NULL))
1946 		return 0;
1947 	if (a != NULL && strcmp(a, b) != 0)
1948 		return 0;
1949 	return 1;
1950 }
1951 
1952 /*
1953  * Compare two forwards, returning non-zero if they are identical or
1954  * zero otherwise.
1955  */
1956 int
1957 forward_equals(const struct Forward *a, const struct Forward *b)
1958 {
1959 	if (strcmp_maybe_null(a->listen_host, b->listen_host) == 0)
1960 		return 0;
1961 	if (a->listen_port != b->listen_port)
1962 		return 0;
1963 	if (strcmp_maybe_null(a->listen_path, b->listen_path) == 0)
1964 		return 0;
1965 	if (strcmp_maybe_null(a->connect_host, b->connect_host) == 0)
1966 		return 0;
1967 	if (a->connect_port != b->connect_port)
1968 		return 0;
1969 	if (strcmp_maybe_null(a->connect_path, b->connect_path) == 0)
1970 		return 0;
1971 	/* allocated_port and handle are not checked */
1972 	return 1;
1973 }
1974 
1975 /* returns 1 if process is already daemonized, 0 otherwise */
1976 int
1977 daemonized(void)
1978 {
1979 	int fd;
1980 
1981 	if ((fd = open(_PATH_TTY, O_RDONLY | O_NOCTTY)) >= 0) {
1982 		close(fd);
1983 		return 0;	/* have controlling terminal */
1984 	}
1985 	if (getppid() != 1)
1986 		return 0;	/* parent is not init */
1987 	if (getsid(0) != getpid())
1988 		return 0;	/* not session leader */
1989 	debug3("already daemonized");
1990 	return 1;
1991 }
1992 
1993 /*
1994  * Splits 's' into an argument vector. Handles quoted string and basic
1995  * escape characters (\\, \", \'). Caller must free the argument vector
1996  * and its members.
1997  */
1998 int
1999 argv_split(const char *s, int *argcp, char ***argvp, int terminate_on_comment)
2000 {
2001 	int r = SSH_ERR_INTERNAL_ERROR;
2002 	int argc = 0, quote, i, j;
2003 	char *arg, **argv = xcalloc(1, sizeof(*argv));
2004 
2005 	*argvp = NULL;
2006 	*argcp = 0;
2007 
2008 	for (i = 0; s[i] != '\0'; i++) {
2009 		/* Skip leading whitespace */
2010 		if (s[i] == ' ' || s[i] == '\t')
2011 			continue;
2012 		if (terminate_on_comment && s[i] == '#')
2013 			break;
2014 		/* Start of a token */
2015 		quote = 0;
2016 
2017 		argv = xreallocarray(argv, (argc + 2), sizeof(*argv));
2018 		arg = argv[argc++] = xcalloc(1, strlen(s + i) + 1);
2019 		argv[argc] = NULL;
2020 
2021 		/* Copy the token in, removing escapes */
2022 		for (j = 0; s[i] != '\0'; i++) {
2023 			if (s[i] == '\\') {
2024 				if (s[i + 1] == '\'' ||
2025 				    s[i + 1] == '\"' ||
2026 				    s[i + 1] == '\\' ||
2027 				    (quote == 0 && s[i + 1] == ' ')) {
2028 					i++; /* Skip '\' */
2029 					arg[j++] = s[i];
2030 				} else {
2031 					/* Unrecognised escape */
2032 					arg[j++] = s[i];
2033 				}
2034 			} else if (quote == 0 && (s[i] == ' ' || s[i] == '\t'))
2035 				break; /* done */
2036 			else if (quote == 0 && (s[i] == '\"' || s[i] == '\''))
2037 				quote = s[i]; /* quote start */
2038 			else if (quote != 0 && s[i] == quote)
2039 				quote = 0; /* quote end */
2040 			else
2041 				arg[j++] = s[i];
2042 		}
2043 		if (s[i] == '\0') {
2044 			if (quote != 0) {
2045 				/* Ran out of string looking for close quote */
2046 				r = SSH_ERR_INVALID_FORMAT;
2047 				goto out;
2048 			}
2049 			break;
2050 		}
2051 	}
2052 	/* Success */
2053 	*argcp = argc;
2054 	*argvp = argv;
2055 	argc = 0;
2056 	argv = NULL;
2057 	r = 0;
2058  out:
2059 	if (argc != 0 && argv != NULL) {
2060 		for (i = 0; i < argc; i++)
2061 			free(argv[i]);
2062 		free(argv);
2063 	}
2064 	return r;
2065 }
2066 
2067 /*
2068  * Reassemble an argument vector into a string, quoting and escaping as
2069  * necessary. Caller must free returned string.
2070  */
2071 char *
2072 argv_assemble(int argc, char **argv)
2073 {
2074 	int i, j, ws, r;
2075 	char c, *ret;
2076 	struct sshbuf *buf, *arg;
2077 
2078 	if ((buf = sshbuf_new()) == NULL || (arg = sshbuf_new()) == NULL)
2079 		fatal_f("sshbuf_new failed");
2080 
2081 	for (i = 0; i < argc; i++) {
2082 		ws = 0;
2083 		sshbuf_reset(arg);
2084 		for (j = 0; argv[i][j] != '\0'; j++) {
2085 			r = 0;
2086 			c = argv[i][j];
2087 			switch (c) {
2088 			case ' ':
2089 			case '\t':
2090 				ws = 1;
2091 				r = sshbuf_put_u8(arg, c);
2092 				break;
2093 			case '\\':
2094 			case '\'':
2095 			case '"':
2096 				if ((r = sshbuf_put_u8(arg, '\\')) != 0)
2097 					break;
2098 				/* FALLTHROUGH */
2099 			default:
2100 				r = sshbuf_put_u8(arg, c);
2101 				break;
2102 			}
2103 			if (r != 0)
2104 				fatal_fr(r, "sshbuf_put_u8");
2105 		}
2106 		if ((i != 0 && (r = sshbuf_put_u8(buf, ' ')) != 0) ||
2107 		    (ws != 0 && (r = sshbuf_put_u8(buf, '"')) != 0) ||
2108 		    (r = sshbuf_putb(buf, arg)) != 0 ||
2109 		    (ws != 0 && (r = sshbuf_put_u8(buf, '"')) != 0))
2110 			fatal_fr(r, "assemble");
2111 	}
2112 	if ((ret = malloc(sshbuf_len(buf) + 1)) == NULL)
2113 		fatal_f("malloc failed");
2114 	memcpy(ret, sshbuf_ptr(buf), sshbuf_len(buf));
2115 	ret[sshbuf_len(buf)] = '\0';
2116 	sshbuf_free(buf);
2117 	sshbuf_free(arg);
2118 	return ret;
2119 }
2120 
2121 char *
2122 argv_next(int *argcp, char ***argvp)
2123 {
2124 	char *ret = (*argvp)[0];
2125 
2126 	if (*argcp > 0 && ret != NULL) {
2127 		(*argcp)--;
2128 		(*argvp)++;
2129 	}
2130 	return ret;
2131 }
2132 
2133 void
2134 argv_consume(int *argcp)
2135 {
2136 	*argcp = 0;
2137 }
2138 
2139 void
2140 argv_free(char **av, int ac)
2141 {
2142 	int i;
2143 
2144 	if (av == NULL)
2145 		return;
2146 	for (i = 0; i < ac; i++)
2147 		free(av[i]);
2148 	free(av);
2149 }
2150 
2151 /* Returns 0 if pid exited cleanly, non-zero otherwise */
2152 int
2153 exited_cleanly(pid_t pid, const char *tag, const char *cmd, int quiet)
2154 {
2155 	int status;
2156 
2157 	while (waitpid(pid, &status, 0) == -1) {
2158 		if (errno != EINTR) {
2159 			error("%s waitpid: %s", tag, strerror(errno));
2160 			return -1;
2161 		}
2162 	}
2163 	if (WIFSIGNALED(status)) {
2164 		error("%s %s exited on signal %d", tag, cmd, WTERMSIG(status));
2165 		return -1;
2166 	} else if (WEXITSTATUS(status) != 0) {
2167 		do_log2(quiet ? SYSLOG_LEVEL_DEBUG1 : SYSLOG_LEVEL_INFO,
2168 		    "%s %s failed, status %d", tag, cmd, WEXITSTATUS(status));
2169 		return -1;
2170 	}
2171 	return 0;
2172 }
2173 
2174 /*
2175  * Check a given path for security. This is defined as all components
2176  * of the path to the file must be owned by either the owner of
2177  * of the file or root and no directories must be group or world writable.
2178  *
2179  * XXX Should any specific check be done for sym links ?
2180  *
2181  * Takes a file name, its stat information (preferably from fstat() to
2182  * avoid races), the uid of the expected owner, their home directory and an
2183  * error buffer plus max size as arguments.
2184  *
2185  * Returns 0 on success and -1 on failure
2186  */
2187 int
2188 safe_path(const char *name, struct stat *stp, const char *pw_dir,
2189     uid_t uid, char *err, size_t errlen)
2190 {
2191 	char buf[PATH_MAX], homedir[PATH_MAX];
2192 	char *cp;
2193 	int comparehome = 0;
2194 	struct stat st;
2195 
2196 	if (realpath(name, buf) == NULL) {
2197 		snprintf(err, errlen, "realpath %s failed: %s", name,
2198 		    strerror(errno));
2199 		return -1;
2200 	}
2201 	if (pw_dir != NULL && realpath(pw_dir, homedir) != NULL)
2202 		comparehome = 1;
2203 
2204 	if (!S_ISREG(stp->st_mode)) {
2205 		snprintf(err, errlen, "%s is not a regular file", buf);
2206 		return -1;
2207 	}
2208 	if ((!platform_sys_dir_uid(stp->st_uid) && stp->st_uid != uid) ||
2209 	    (stp->st_mode & 022) != 0) {
2210 		snprintf(err, errlen, "bad ownership or modes for file %s",
2211 		    buf);
2212 		return -1;
2213 	}
2214 
2215 	/* for each component of the canonical path, walking upwards */
2216 	for (;;) {
2217 		if ((cp = dirname(buf)) == NULL) {
2218 			snprintf(err, errlen, "dirname() failed");
2219 			return -1;
2220 		}
2221 		strlcpy(buf, cp, sizeof(buf));
2222 
2223 		if (stat(buf, &st) == -1 ||
2224 		    (!platform_sys_dir_uid(st.st_uid) && st.st_uid != uid) ||
2225 		    (st.st_mode & 022) != 0) {
2226 			snprintf(err, errlen,
2227 			    "bad ownership or modes for directory %s", buf);
2228 			return -1;
2229 		}
2230 
2231 		/* If are past the homedir then we can stop */
2232 		if (comparehome && strcmp(homedir, buf) == 0)
2233 			break;
2234 
2235 		/*
2236 		 * dirname should always complete with a "/" path,
2237 		 * but we can be paranoid and check for "." too
2238 		 */
2239 		if ((strcmp("/", buf) == 0) || (strcmp(".", buf) == 0))
2240 			break;
2241 	}
2242 	return 0;
2243 }
2244 
2245 /*
2246  * Version of safe_path() that accepts an open file descriptor to
2247  * avoid races.
2248  *
2249  * Returns 0 on success and -1 on failure
2250  */
2251 int
2252 safe_path_fd(int fd, const char *file, struct passwd *pw,
2253     char *err, size_t errlen)
2254 {
2255 	struct stat st;
2256 
2257 	/* check the open file to avoid races */
2258 	if (fstat(fd, &st) == -1) {
2259 		snprintf(err, errlen, "cannot stat file %s: %s",
2260 		    file, strerror(errno));
2261 		return -1;
2262 	}
2263 	return safe_path(file, &st, pw->pw_dir, pw->pw_uid, err, errlen);
2264 }
2265 
2266 /*
2267  * Sets the value of the given variable in the environment.  If the variable
2268  * already exists, its value is overridden.
2269  */
2270 void
2271 child_set_env(char ***envp, u_int *envsizep, const char *name,
2272 	const char *value)
2273 {
2274 	char **env;
2275 	u_int envsize;
2276 	u_int i, namelen;
2277 
2278 	if (strchr(name, '=') != NULL) {
2279 		error("Invalid environment variable \"%.100s\"", name);
2280 		return;
2281 	}
2282 
2283 	/*
2284 	 * If we're passed an uninitialized list, allocate a single null
2285 	 * entry before continuing.
2286 	 */
2287 	if ((*envp == NULL) != (*envsizep == 0))
2288 		fatal_f("environment size mismatch");
2289 	if (*envp == NULL && *envsizep == 0) {
2290 		*envp = xmalloc(sizeof(char *));
2291 		*envp[0] = NULL;
2292 		*envsizep = 1;
2293 	}
2294 
2295 	/*
2296 	 * Find the slot where the value should be stored.  If the variable
2297 	 * already exists, we reuse the slot; otherwise we append a new slot
2298 	 * at the end of the array, expanding if necessary.
2299 	 */
2300 	env = *envp;
2301 	namelen = strlen(name);
2302 	for (i = 0; env[i]; i++)
2303 		if (strncmp(env[i], name, namelen) == 0 && env[i][namelen] == '=')
2304 			break;
2305 	if (env[i]) {
2306 		/* Reuse the slot. */
2307 		free(env[i]);
2308 	} else {
2309 		/* New variable.  Expand if necessary. */
2310 		envsize = *envsizep;
2311 		if (i >= envsize - 1) {
2312 			if (envsize >= 1000)
2313 				fatal("child_set_env: too many env vars");
2314 			envsize += 50;
2315 			env = (*envp) = xreallocarray(env, envsize, sizeof(char *));
2316 			*envsizep = envsize;
2317 		}
2318 		/* Need to set the NULL pointer at end of array beyond the new slot. */
2319 		env[i + 1] = NULL;
2320 	}
2321 
2322 	/* Allocate space and format the variable in the appropriate slot. */
2323 	/* XXX xasprintf */
2324 	env[i] = xmalloc(strlen(name) + 1 + strlen(value) + 1);
2325 	snprintf(env[i], strlen(name) + 1 + strlen(value) + 1, "%s=%s", name, value);
2326 }
2327 
2328 /*
2329  * Check and optionally lowercase a domain name, also removes trailing '.'
2330  * Returns 1 on success and 0 on failure, storing an error message in errstr.
2331  */
2332 int
2333 valid_domain(char *name, int makelower, const char **errstr)
2334 {
2335 	size_t i, l = strlen(name);
2336 	u_char c, last = '\0';
2337 	static char errbuf[256];
2338 
2339 	if (l == 0) {
2340 		strlcpy(errbuf, "empty domain name", sizeof(errbuf));
2341 		goto bad;
2342 	}
2343 	if (!isalpha((u_char)name[0]) && !isdigit((u_char)name[0])) {
2344 		snprintf(errbuf, sizeof(errbuf), "domain name \"%.100s\" "
2345 		    "starts with invalid character", name);
2346 		goto bad;
2347 	}
2348 	for (i = 0; i < l; i++) {
2349 		c = tolower((u_char)name[i]);
2350 		if (makelower)
2351 			name[i] = (char)c;
2352 		if (last == '.' && c == '.') {
2353 			snprintf(errbuf, sizeof(errbuf), "domain name "
2354 			    "\"%.100s\" contains consecutive separators", name);
2355 			goto bad;
2356 		}
2357 		if (c != '.' && c != '-' && !isalnum(c) &&
2358 		    c != '_') /* technically invalid, but common */ {
2359 			snprintf(errbuf, sizeof(errbuf), "domain name "
2360 			    "\"%.100s\" contains invalid characters", name);
2361 			goto bad;
2362 		}
2363 		last = c;
2364 	}
2365 	if (name[l - 1] == '.')
2366 		name[l - 1] = '\0';
2367 	if (errstr != NULL)
2368 		*errstr = NULL;
2369 	return 1;
2370 bad:
2371 	if (errstr != NULL)
2372 		*errstr = errbuf;
2373 	return 0;
2374 }
2375 
2376 /*
2377  * Verify that a environment variable name (not including initial '$') is
2378  * valid; consisting of one or more alphanumeric or underscore characters only.
2379  * Returns 1 on valid, 0 otherwise.
2380  */
2381 int
2382 valid_env_name(const char *name)
2383 {
2384 	const char *cp;
2385 
2386 	if (name[0] == '\0')
2387 		return 0;
2388 	for (cp = name; *cp != '\0'; cp++) {
2389 		if (!isalnum((u_char)*cp) && *cp != '_')
2390 			return 0;
2391 	}
2392 	return 1;
2393 }
2394 
2395 const char *
2396 atoi_err(const char *nptr, int *val)
2397 {
2398 	const char *errstr = NULL;
2399 	long long num;
2400 
2401 	if (nptr == NULL || *nptr == '\0')
2402 		return "missing";
2403 	num = strtonum(nptr, 0, INT_MAX, &errstr);
2404 	if (errstr == NULL)
2405 		*val = (int)num;
2406 	return errstr;
2407 }
2408 
2409 int
2410 parse_absolute_time(const char *s, uint64_t *tp)
2411 {
2412 	struct tm tm;
2413 	time_t tt;
2414 	char buf[32], *fmt;
2415 	const char *cp;
2416 	size_t l;
2417 	int is_utc = 0;
2418 
2419 	*tp = 0;
2420 
2421 	l = strlen(s);
2422 	if (l > 1 && strcasecmp(s + l - 1, "Z") == 0) {
2423 		is_utc = 1;
2424 		l--;
2425 	} else if (l > 3 && strcasecmp(s + l - 3, "UTC") == 0) {
2426 		is_utc = 1;
2427 		l -= 3;
2428 	}
2429 	/*
2430 	 * POSIX strptime says "The application shall ensure that there
2431 	 * is white-space or other non-alphanumeric characters between
2432 	 * any two conversion specifications" so arrange things this way.
2433 	 */
2434 	switch (l) {
2435 	case 8: /* YYYYMMDD */
2436 		fmt = "%Y-%m-%d";
2437 		snprintf(buf, sizeof(buf), "%.4s-%.2s-%.2s", s, s + 4, s + 6);
2438 		break;
2439 	case 12: /* YYYYMMDDHHMM */
2440 		fmt = "%Y-%m-%dT%H:%M";
2441 		snprintf(buf, sizeof(buf), "%.4s-%.2s-%.2sT%.2s:%.2s",
2442 		    s, s + 4, s + 6, s + 8, s + 10);
2443 		break;
2444 	case 14: /* YYYYMMDDHHMMSS */
2445 		fmt = "%Y-%m-%dT%H:%M:%S";
2446 		snprintf(buf, sizeof(buf), "%.4s-%.2s-%.2sT%.2s:%.2s:%.2s",
2447 		    s, s + 4, s + 6, s + 8, s + 10, s + 12);
2448 		break;
2449 	default:
2450 		return SSH_ERR_INVALID_FORMAT;
2451 	}
2452 
2453 	memset(&tm, 0, sizeof(tm));
2454 	if ((cp = strptime(buf, fmt, &tm)) == NULL || *cp != '\0')
2455 		return SSH_ERR_INVALID_FORMAT;
2456 	if (is_utc) {
2457 		if ((tt = timegm(&tm)) < 0)
2458 			return SSH_ERR_INVALID_FORMAT;
2459 	} else {
2460 		if ((tt = mktime(&tm)) < 0)
2461 			return SSH_ERR_INVALID_FORMAT;
2462 	}
2463 	/* success */
2464 	*tp = (uint64_t)tt;
2465 	return 0;
2466 }
2467 
2468 void
2469 format_absolute_time(uint64_t t, char *buf, size_t len)
2470 {
2471 	time_t tt = t > SSH_TIME_T_MAX ? SSH_TIME_T_MAX : t;
2472 	struct tm tm;
2473 
2474 	localtime_r(&tt, &tm);
2475 	strftime(buf, len, "%Y-%m-%dT%H:%M:%S", &tm);
2476 }
2477 
2478 /* check if path is absolute */
2479 int
2480 path_absolute(const char *path)
2481 {
2482 	return (*path == '/') ? 1 : 0;
2483 }
2484 
2485 void
2486 skip_space(char **cpp)
2487 {
2488 	char *cp;
2489 
2490 	for (cp = *cpp; *cp == ' ' || *cp == '\t'; cp++)
2491 		;
2492 	*cpp = cp;
2493 }
2494 
2495 /* authorized_key-style options parsing helpers */
2496 
2497 /*
2498  * Match flag 'opt' in *optsp, and if allow_negate is set then also match
2499  * 'no-opt'. Returns -1 if option not matched, 1 if option matches or 0
2500  * if negated option matches.
2501  * If the option or negated option matches, then *optsp is updated to
2502  * point to the first character after the option.
2503  */
2504 int
2505 opt_flag(const char *opt, int allow_negate, const char **optsp)
2506 {
2507 	size_t opt_len = strlen(opt);
2508 	const char *opts = *optsp;
2509 	int negate = 0;
2510 
2511 	if (allow_negate && strncasecmp(opts, "no-", 3) == 0) {
2512 		opts += 3;
2513 		negate = 1;
2514 	}
2515 	if (strncasecmp(opts, opt, opt_len) == 0) {
2516 		*optsp = opts + opt_len;
2517 		return negate ? 0 : 1;
2518 	}
2519 	return -1;
2520 }
2521 
2522 char *
2523 opt_dequote(const char **sp, const char **errstrp)
2524 {
2525 	const char *s = *sp;
2526 	char *ret;
2527 	size_t i;
2528 
2529 	*errstrp = NULL;
2530 	if (*s != '"') {
2531 		*errstrp = "missing start quote";
2532 		return NULL;
2533 	}
2534 	s++;
2535 	if ((ret = malloc(strlen((s)) + 1)) == NULL) {
2536 		*errstrp = "memory allocation failed";
2537 		return NULL;
2538 	}
2539 	for (i = 0; *s != '\0' && *s != '"';) {
2540 		if (s[0] == '\\' && s[1] == '"')
2541 			s++;
2542 		ret[i++] = *s++;
2543 	}
2544 	if (*s == '\0') {
2545 		*errstrp = "missing end quote";
2546 		free(ret);
2547 		return NULL;
2548 	}
2549 	ret[i] = '\0';
2550 	s++;
2551 	*sp = s;
2552 	return ret;
2553 }
2554 
2555 int
2556 opt_match(const char **opts, const char *term)
2557 {
2558 	if (strncasecmp((*opts), term, strlen(term)) == 0 &&
2559 	    (*opts)[strlen(term)] == '=') {
2560 		*opts += strlen(term) + 1;
2561 		return 1;
2562 	}
2563 	return 0;
2564 }
2565 
2566 void
2567 opt_array_append2(const char *file, const int line, const char *directive,
2568     char ***array, int **iarray, u_int *lp, const char *s, int i)
2569 {
2570 
2571 	if (*lp >= INT_MAX)
2572 		fatal("%s line %d: Too many %s entries", file, line, directive);
2573 
2574 	if (iarray != NULL) {
2575 		*iarray = xrecallocarray(*iarray, *lp, *lp + 1,
2576 		    sizeof(**iarray));
2577 		(*iarray)[*lp] = i;
2578 	}
2579 
2580 	*array = xrecallocarray(*array, *lp, *lp + 1, sizeof(**array));
2581 	(*array)[*lp] = xstrdup(s);
2582 	(*lp)++;
2583 }
2584 
2585 void
2586 opt_array_append(const char *file, const int line, const char *directive,
2587     char ***array, u_int *lp, const char *s)
2588 {
2589 	opt_array_append2(file, line, directive, array, NULL, lp, s, 0);
2590 }
2591 
2592 sshsig_t
2593 ssh_signal(int signum, sshsig_t handler)
2594 {
2595 	struct sigaction sa, osa;
2596 
2597 	/* mask all other signals while in handler */
2598 	memset(&sa, 0, sizeof(sa));
2599 	sa.sa_handler = handler;
2600 	sigfillset(&sa.sa_mask);
2601 #if defined(SA_RESTART) && !defined(NO_SA_RESTART)
2602 	if (signum != SIGALRM)
2603 		sa.sa_flags = SA_RESTART;
2604 #endif
2605 	if (sigaction(signum, &sa, &osa) == -1) {
2606 		debug3("sigaction(%s): %s", strsignal(signum), strerror(errno));
2607 		return SIG_ERR;
2608 	}
2609 	return osa.sa_handler;
2610 }
2611 
2612 int
2613 stdfd_devnull(int do_stdin, int do_stdout, int do_stderr)
2614 {
2615 	int devnull, ret = 0;
2616 
2617 	if ((devnull = open(_PATH_DEVNULL, O_RDWR)) == -1) {
2618 		error_f("open %s: %s", _PATH_DEVNULL,
2619 		    strerror(errno));
2620 		return -1;
2621 	}
2622 	if ((do_stdin && dup2(devnull, STDIN_FILENO) == -1) ||
2623 	    (do_stdout && dup2(devnull, STDOUT_FILENO) == -1) ||
2624 	    (do_stderr && dup2(devnull, STDERR_FILENO) == -1)) {
2625 		error_f("dup2: %s", strerror(errno));
2626 		ret = -1;
2627 	}
2628 	if (devnull > STDERR_FILENO)
2629 		close(devnull);
2630 	return ret;
2631 }
2632 
2633 /*
2634  * Runs command in a subprocess with a minimal environment.
2635  * Returns pid on success, 0 on failure.
2636  * The child stdout and stderr maybe captured, left attached or sent to
2637  * /dev/null depending on the contents of flags.
2638  * "tag" is prepended to log messages.
2639  * NB. "command" is only used for logging; the actual command executed is
2640  * av[0].
2641  */
2642 pid_t
2643 subprocess(const char *tag, const char *command,
2644     int ac, char **av, FILE **child, u_int flags,
2645     struct passwd *pw, privdrop_fn *drop_privs, privrestore_fn *restore_privs)
2646 {
2647 	FILE *f = NULL;
2648 	struct stat st;
2649 	int fd, devnull, p[2], i;
2650 	pid_t pid;
2651 	char *cp, errmsg[512];
2652 	u_int nenv = 0;
2653 	char **env = NULL;
2654 
2655 	/* If dropping privs, then must specify user and restore function */
2656 	if (drop_privs != NULL && (pw == NULL || restore_privs == NULL)) {
2657 		error("%s: inconsistent arguments", tag); /* XXX fatal? */
2658 		return 0;
2659 	}
2660 	if (pw == NULL && (pw = getpwuid(getuid())) == NULL) {
2661 		error("%s: no user for current uid", tag);
2662 		return 0;
2663 	}
2664 	if (child != NULL)
2665 		*child = NULL;
2666 
2667 	debug3_f("%s command \"%s\" running as %s (flags 0x%x)",
2668 	    tag, command, pw->pw_name, flags);
2669 
2670 	/* Check consistency */
2671 	if ((flags & SSH_SUBPROCESS_STDOUT_DISCARD) != 0 &&
2672 	    (flags & SSH_SUBPROCESS_STDOUT_CAPTURE) != 0) {
2673 		error_f("inconsistent flags");
2674 		return 0;
2675 	}
2676 	if (((flags & SSH_SUBPROCESS_STDOUT_CAPTURE) == 0) != (child == NULL)) {
2677 		error_f("inconsistent flags/output");
2678 		return 0;
2679 	}
2680 
2681 	/*
2682 	 * If executing an explicit binary, then verify the it exists
2683 	 * and appears safe-ish to execute
2684 	 */
2685 	if (!path_absolute(av[0])) {
2686 		error("%s path is not absolute", tag);
2687 		return 0;
2688 	}
2689 	if (drop_privs != NULL)
2690 		drop_privs(pw);
2691 	if (stat(av[0], &st) == -1) {
2692 		error("Could not stat %s \"%s\": %s", tag,
2693 		    av[0], strerror(errno));
2694 		goto restore_return;
2695 	}
2696 	if ((flags & SSH_SUBPROCESS_UNSAFE_PATH) == 0 &&
2697 	    safe_path(av[0], &st, NULL, 0, errmsg, sizeof(errmsg)) != 0) {
2698 		error("Unsafe %s \"%s\": %s", tag, av[0], errmsg);
2699 		goto restore_return;
2700 	}
2701 	/* Prepare to keep the child's stdout if requested */
2702 	if (pipe(p) == -1) {
2703 		error("%s: pipe: %s", tag, strerror(errno));
2704  restore_return:
2705 		if (restore_privs != NULL)
2706 			restore_privs();
2707 		return 0;
2708 	}
2709 	if (restore_privs != NULL)
2710 		restore_privs();
2711 
2712 	switch ((pid = fork())) {
2713 	case -1: /* error */
2714 		error("%s: fork: %s", tag, strerror(errno));
2715 		close(p[0]);
2716 		close(p[1]);
2717 		return 0;
2718 	case 0: /* child */
2719 		/* Prepare a minimal environment for the child. */
2720 		if ((flags & SSH_SUBPROCESS_PRESERVE_ENV) == 0) {
2721 			nenv = 5;
2722 			env = xcalloc(sizeof(*env), nenv);
2723 			child_set_env(&env, &nenv, "PATH", _PATH_STDPATH);
2724 			child_set_env(&env, &nenv, "USER", pw->pw_name);
2725 			child_set_env(&env, &nenv, "LOGNAME", pw->pw_name);
2726 			child_set_env(&env, &nenv, "HOME", pw->pw_dir);
2727 			if ((cp = getenv("LANG")) != NULL)
2728 				child_set_env(&env, &nenv, "LANG", cp);
2729 		}
2730 
2731 		for (i = 1; i < NSIG; i++)
2732 			ssh_signal(i, SIG_DFL);
2733 
2734 		if ((devnull = open(_PATH_DEVNULL, O_RDWR)) == -1) {
2735 			error("%s: open %s: %s", tag, _PATH_DEVNULL,
2736 			    strerror(errno));
2737 			_exit(1);
2738 		}
2739 		if (dup2(devnull, STDIN_FILENO) == -1) {
2740 			error("%s: dup2: %s", tag, strerror(errno));
2741 			_exit(1);
2742 		}
2743 
2744 		/* Set up stdout as requested; leave stderr in place for now. */
2745 		fd = -1;
2746 		if ((flags & SSH_SUBPROCESS_STDOUT_CAPTURE) != 0)
2747 			fd = p[1];
2748 		else if ((flags & SSH_SUBPROCESS_STDOUT_DISCARD) != 0)
2749 			fd = devnull;
2750 		if (fd != -1 && dup2(fd, STDOUT_FILENO) == -1) {
2751 			error("%s: dup2: %s", tag, strerror(errno));
2752 			_exit(1);
2753 		}
2754 		closefrom(STDERR_FILENO + 1);
2755 
2756 		if (geteuid() == 0 &&
2757 		    initgroups(pw->pw_name, pw->pw_gid) == -1) {
2758 			error("%s: initgroups(%s, %u): %s", tag,
2759 			    pw->pw_name, (u_int)pw->pw_gid, strerror(errno));
2760 			_exit(1);
2761 		}
2762 		if (setresgid(pw->pw_gid, pw->pw_gid, pw->pw_gid) == -1) {
2763 			error("%s: setresgid %u: %s", tag, (u_int)pw->pw_gid,
2764 			    strerror(errno));
2765 			_exit(1);
2766 		}
2767 		if (setresuid(pw->pw_uid, pw->pw_uid, pw->pw_uid) == -1) {
2768 			error("%s: setresuid %u: %s", tag, (u_int)pw->pw_uid,
2769 			    strerror(errno));
2770 			_exit(1);
2771 		}
2772 		/* stdin is pointed to /dev/null at this point */
2773 		if ((flags & SSH_SUBPROCESS_STDOUT_DISCARD) != 0 &&
2774 		    dup2(STDIN_FILENO, STDERR_FILENO) == -1) {
2775 			error("%s: dup2: %s", tag, strerror(errno));
2776 			_exit(1);
2777 		}
2778 		if (env != NULL)
2779 			execve(av[0], av, env);
2780 		else
2781 			execv(av[0], av);
2782 		error("%s %s \"%s\": %s", tag, env == NULL ? "execv" : "execve",
2783 		    command, strerror(errno));
2784 		_exit(127);
2785 	default: /* parent */
2786 		break;
2787 	}
2788 
2789 	close(p[1]);
2790 	if ((flags & SSH_SUBPROCESS_STDOUT_CAPTURE) == 0)
2791 		close(p[0]);
2792 	else if ((f = fdopen(p[0], "r")) == NULL) {
2793 		error("%s: fdopen: %s", tag, strerror(errno));
2794 		close(p[0]);
2795 		/* Don't leave zombie child */
2796 		kill(pid, SIGTERM);
2797 		while (waitpid(pid, NULL, 0) == -1 && errno == EINTR)
2798 			;
2799 		return 0;
2800 	}
2801 	/* Success */
2802 	debug3_f("%s pid %ld", tag, (long)pid);
2803 	if (child != NULL)
2804 		*child = f;
2805 	return pid;
2806 }
2807 
2808 const char *
2809 lookup_env_in_list(const char *env, char * const *envs, size_t nenvs)
2810 {
2811 	size_t i, envlen;
2812 
2813 	envlen = strlen(env);
2814 	for (i = 0; i < nenvs; i++) {
2815 		if (strncmp(envs[i], env, envlen) == 0 &&
2816 		    envs[i][envlen] == '=') {
2817 			return envs[i] + envlen + 1;
2818 		}
2819 	}
2820 	return NULL;
2821 }
2822 
2823 const char *
2824 lookup_setenv_in_list(const char *env, char * const *envs, size_t nenvs)
2825 {
2826 	char *name, *cp;
2827 	const char *ret;
2828 
2829 	name = xstrdup(env);
2830 	if ((cp = strchr(name, '=')) == NULL) {
2831 		free(name);
2832 		return NULL; /* not env=val */
2833 	}
2834 	*cp = '\0';
2835 	ret = lookup_env_in_list(name, envs, nenvs);
2836 	free(name);
2837 	return ret;
2838 }
2839 
2840 /*
2841  * Helpers for managing poll(2)/ppoll(2) timeouts
2842  * Will remember the earliest deadline and return it for use in poll/ppoll.
2843  */
2844 
2845 /* Initialise a poll/ppoll timeout with an indefinite deadline */
2846 void
2847 ptimeout_init(struct timespec *pt)
2848 {
2849 	/*
2850 	 * Deliberately invalid for ppoll(2).
2851 	 * Will be converted to NULL in ptimeout_get_tspec() later.
2852 	 */
2853 	pt->tv_sec = -1;
2854 	pt->tv_nsec = 0;
2855 }
2856 
2857 /* Specify a poll/ppoll deadline of at most 'sec' seconds */
2858 void
2859 ptimeout_deadline_sec(struct timespec *pt, long sec)
2860 {
2861 	if (pt->tv_sec == -1 || pt->tv_sec >= sec) {
2862 		pt->tv_sec = sec;
2863 		pt->tv_nsec = 0;
2864 	}
2865 }
2866 
2867 /* Specify a poll/ppoll deadline of at most 'p' (timespec) */
2868 static void
2869 ptimeout_deadline_tsp(struct timespec *pt, struct timespec *p)
2870 {
2871 	if (pt->tv_sec == -1 || timespeccmp(pt, p, >=))
2872 		*pt = *p;
2873 }
2874 
2875 /* Specify a poll/ppoll deadline of at most 'ms' milliseconds */
2876 void
2877 ptimeout_deadline_ms(struct timespec *pt, long ms)
2878 {
2879 	struct timespec p;
2880 
2881 	p.tv_sec = ms / 1000;
2882 	p.tv_nsec = (ms % 1000) * 1000000;
2883 	ptimeout_deadline_tsp(pt, &p);
2884 }
2885 
2886 /* Specify a poll/ppoll deadline at wall clock monotime 'when' */
2887 void
2888 ptimeout_deadline_monotime(struct timespec *pt, time_t when)
2889 {
2890 	struct timespec now, t;
2891 
2892 	t.tv_sec = when;
2893 	t.tv_nsec = 0;
2894 	monotime_ts(&now);
2895 
2896 	if (timespeccmp(&now, &t, >=))
2897 		ptimeout_deadline_sec(pt, 0);
2898 	else {
2899 		timespecsub(&t, &now, &t);
2900 		ptimeout_deadline_tsp(pt, &t);
2901 	}
2902 }
2903 
2904 /* Get a poll(2) timeout value in milliseconds */
2905 int
2906 ptimeout_get_ms(struct timespec *pt)
2907 {
2908 	if (pt->tv_sec == -1)
2909 		return -1;
2910 	if (pt->tv_sec >= (INT_MAX - (pt->tv_nsec / 1000000)) / 1000)
2911 		return INT_MAX;
2912 	return (pt->tv_sec * 1000) + (pt->tv_nsec / 1000000);
2913 }
2914 
2915 /* Get a ppoll(2) timeout value as a timespec pointer */
2916 struct timespec *
2917 ptimeout_get_tsp(struct timespec *pt)
2918 {
2919 	return pt->tv_sec == -1 ? NULL : pt;
2920 }
2921 
2922 /* Returns non-zero if a timeout has been set (i.e. is not indefinite) */
2923 int
2924 ptimeout_isset(struct timespec *pt)
2925 {
2926 	return pt->tv_sec != -1;
2927 }
2928 
2929 /*
2930  * Returns zero if the library at 'path' contains symbol 's', nonzero
2931  * otherwise.
2932  */
2933 int
2934 lib_contains_symbol(const char *path, const char *s)
2935 {
2936 #ifdef HAVE_NLIST_H
2937 	struct nlist nl[2];
2938 	int ret = -1, r;
2939 
2940 	memset(nl, 0, sizeof(nl));
2941 	nl[0].n_name = xstrdup(s);
2942 	nl[1].n_name = NULL;
2943 	if ((r = nlist(path, nl)) == -1) {
2944 		error_f("nlist failed for %s", path);
2945 		goto out;
2946 	}
2947 	if (r != 0 || nl[0].n_value == 0 || nl[0].n_type == 0) {
2948 		error_f("library %s does not contain symbol %s", path, s);
2949 		goto out;
2950 	}
2951 	/* success */
2952 	ret = 0;
2953  out:
2954 	free(nl[0].n_name);
2955 	return ret;
2956 #else /* HAVE_NLIST_H */
2957 	int fd, ret = -1;
2958 	struct stat st;
2959 	void *m = NULL;
2960 	size_t sz = 0;
2961 
2962 	memset(&st, 0, sizeof(st));
2963 	if ((fd = open(path, O_RDONLY)) < 0) {
2964 		error_f("open %s: %s", path, strerror(errno));
2965 		return -1;
2966 	}
2967 	if (fstat(fd, &st) != 0) {
2968 		error_f("fstat %s: %s", path, strerror(errno));
2969 		goto out;
2970 	}
2971 	if (!S_ISREG(st.st_mode)) {
2972 		error_f("%s is not a regular file", path);
2973 		goto out;
2974 	}
2975 	if (st.st_size < 0 ||
2976 	    (size_t)st.st_size < strlen(s) ||
2977 	    st.st_size >= INT_MAX/2) {
2978 		error_f("%s bad size %lld", path, (long long)st.st_size);
2979 		goto out;
2980 	}
2981 	sz = (size_t)st.st_size;
2982 	if ((m = mmap(NULL, sz, PROT_READ, MAP_PRIVATE, fd, 0)) == MAP_FAILED ||
2983 	    m == NULL) {
2984 		error_f("mmap %s: %s", path, strerror(errno));
2985 		goto out;
2986 	}
2987 	if (memmem(m, sz, s, strlen(s)) == NULL) {
2988 		error_f("%s does not contain expected string %s", path, s);
2989 		goto out;
2990 	}
2991 	/* success */
2992 	ret = 0;
2993  out:
2994 	if (m != NULL && m != MAP_FAILED)
2995 		munmap(m, sz);
2996 	close(fd);
2997 	return ret;
2998 #endif /* HAVE_NLIST_H */
2999 }
3000