xref: /openssh-portable/misc.c (revision 2a35862e)
1 /* $OpenBSD: misc.c,v 1.134 2018/11/16 03:26:01 djm Exp $ */
2 /*
3  * Copyright (c) 2000 Markus Friedl.  All rights reserved.
4  * Copyright (c) 2005,2006 Damien Miller.  All rights reserved.
5  *
6  * Redistribution and use in source and binary forms, with or without
7  * modification, are permitted provided that the following conditions
8  * are met:
9  * 1. Redistributions of source code must retain the above copyright
10  *    notice, this list of conditions and the following disclaimer.
11  * 2. Redistributions in binary form must reproduce the above copyright
12  *    notice, this list of conditions and the following disclaimer in the
13  *    documentation and/or other materials provided with the distribution.
14  *
15  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
16  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
17  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
18  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
19  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
20  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
21  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
22  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
23  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
24  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
25  */
26 
27 #include "includes.h"
28 
29 #include <sys/types.h>
30 #include <sys/ioctl.h>
31 #include <sys/socket.h>
32 #include <sys/stat.h>
33 #include <sys/time.h>
34 #include <sys/wait.h>
35 #include <sys/un.h>
36 
37 #include <limits.h>
38 #ifdef HAVE_LIBGEN_H
39 # include <libgen.h>
40 #endif
41 #include <signal.h>
42 #include <stdarg.h>
43 #include <stdio.h>
44 #include <stdlib.h>
45 #include <string.h>
46 #include <time.h>
47 #include <unistd.h>
48 
49 #include <netinet/in.h>
50 #include <netinet/in_systm.h>
51 #include <netinet/ip.h>
52 #include <netinet/tcp.h>
53 #include <arpa/inet.h>
54 
55 #include <ctype.h>
56 #include <errno.h>
57 #include <fcntl.h>
58 #include <netdb.h>
59 #ifdef HAVE_PATHS_H
60 # include <paths.h>
61 #include <pwd.h>
62 #endif
63 #ifdef SSH_TUN_OPENBSD
64 #include <net/if.h>
65 #endif
66 
67 #include "xmalloc.h"
68 #include "misc.h"
69 #include "log.h"
70 #include "ssh.h"
71 #include "sshbuf.h"
72 #include "ssherr.h"
73 #include "platform.h"
74 
75 /* remove newline at end of string */
76 char *
77 chop(char *s)
78 {
79 	char *t = s;
80 	while (*t) {
81 		if (*t == '\n' || *t == '\r') {
82 			*t = '\0';
83 			return s;
84 		}
85 		t++;
86 	}
87 	return s;
88 
89 }
90 
91 /* set/unset filedescriptor to non-blocking */
92 int
93 set_nonblock(int fd)
94 {
95 	int val;
96 
97 	val = fcntl(fd, F_GETFL);
98 	if (val < 0) {
99 		error("fcntl(%d, F_GETFL): %s", fd, strerror(errno));
100 		return (-1);
101 	}
102 	if (val & O_NONBLOCK) {
103 		debug3("fd %d is O_NONBLOCK", fd);
104 		return (0);
105 	}
106 	debug2("fd %d setting O_NONBLOCK", fd);
107 	val |= O_NONBLOCK;
108 	if (fcntl(fd, F_SETFL, val) == -1) {
109 		debug("fcntl(%d, F_SETFL, O_NONBLOCK): %s", fd,
110 		    strerror(errno));
111 		return (-1);
112 	}
113 	return (0);
114 }
115 
116 int
117 unset_nonblock(int fd)
118 {
119 	int val;
120 
121 	val = fcntl(fd, F_GETFL);
122 	if (val < 0) {
123 		error("fcntl(%d, F_GETFL): %s", fd, strerror(errno));
124 		return (-1);
125 	}
126 	if (!(val & O_NONBLOCK)) {
127 		debug3("fd %d is not O_NONBLOCK", fd);
128 		return (0);
129 	}
130 	debug("fd %d clearing O_NONBLOCK", fd);
131 	val &= ~O_NONBLOCK;
132 	if (fcntl(fd, F_SETFL, val) == -1) {
133 		debug("fcntl(%d, F_SETFL, ~O_NONBLOCK): %s",
134 		    fd, strerror(errno));
135 		return (-1);
136 	}
137 	return (0);
138 }
139 
140 const char *
141 ssh_gai_strerror(int gaierr)
142 {
143 	if (gaierr == EAI_SYSTEM && errno != 0)
144 		return strerror(errno);
145 	return gai_strerror(gaierr);
146 }
147 
148 /* disable nagle on socket */
149 void
150 set_nodelay(int fd)
151 {
152 	int opt;
153 	socklen_t optlen;
154 
155 	optlen = sizeof opt;
156 	if (getsockopt(fd, IPPROTO_TCP, TCP_NODELAY, &opt, &optlen) == -1) {
157 		debug("getsockopt TCP_NODELAY: %.100s", strerror(errno));
158 		return;
159 	}
160 	if (opt == 1) {
161 		debug2("fd %d is TCP_NODELAY", fd);
162 		return;
163 	}
164 	opt = 1;
165 	debug2("fd %d setting TCP_NODELAY", fd);
166 	if (setsockopt(fd, IPPROTO_TCP, TCP_NODELAY, &opt, sizeof opt) == -1)
167 		error("setsockopt TCP_NODELAY: %.100s", strerror(errno));
168 }
169 
170 /* Allow local port reuse in TIME_WAIT */
171 int
172 set_reuseaddr(int fd)
173 {
174 	int on = 1;
175 
176 	if (setsockopt(fd, SOL_SOCKET, SO_REUSEADDR, &on, sizeof(on)) == -1) {
177 		error("setsockopt SO_REUSEADDR fd %d: %s", fd, strerror(errno));
178 		return -1;
179 	}
180 	return 0;
181 }
182 
183 /* Get/set routing domain */
184 char *
185 get_rdomain(int fd)
186 {
187 #if defined(HAVE_SYS_GET_RDOMAIN)
188 	return sys_get_rdomain(fd);
189 #elif defined(__OpenBSD__)
190 	int rtable;
191 	char *ret;
192 	socklen_t len = sizeof(rtable);
193 
194 	if (getsockopt(fd, SOL_SOCKET, SO_RTABLE, &rtable, &len) == -1) {
195 		error("Failed to get routing domain for fd %d: %s",
196 		    fd, strerror(errno));
197 		return NULL;
198 	}
199 	xasprintf(&ret, "%d", rtable);
200 	return ret;
201 #else /* defined(__OpenBSD__) */
202 	return NULL;
203 #endif
204 }
205 
206 int
207 set_rdomain(int fd, const char *name)
208 {
209 #if defined(HAVE_SYS_SET_RDOMAIN)
210 	return sys_set_rdomain(fd, name);
211 #elif defined(__OpenBSD__)
212 	int rtable;
213 	const char *errstr;
214 
215 	if (name == NULL)
216 		return 0; /* default table */
217 
218 	rtable = (int)strtonum(name, 0, 255, &errstr);
219 	if (errstr != NULL) {
220 		/* Shouldn't happen */
221 		error("Invalid routing domain \"%s\": %s", name, errstr);
222 		return -1;
223 	}
224 	if (setsockopt(fd, SOL_SOCKET, SO_RTABLE,
225 	    &rtable, sizeof(rtable)) == -1) {
226 		error("Failed to set routing domain %d on fd %d: %s",
227 		    rtable, fd, strerror(errno));
228 		return -1;
229 	}
230 	return 0;
231 #else /* defined(__OpenBSD__) */
232 	error("Setting routing domain is not supported on this platform");
233 	return -1;
234 #endif
235 }
236 
237 /* Characters considered whitespace in strsep calls. */
238 #define WHITESPACE " \t\r\n"
239 #define QUOTE	"\""
240 
241 /* return next token in configuration line */
242 static char *
243 strdelim_internal(char **s, int split_equals)
244 {
245 	char *old;
246 	int wspace = 0;
247 
248 	if (*s == NULL)
249 		return NULL;
250 
251 	old = *s;
252 
253 	*s = strpbrk(*s,
254 	    split_equals ? WHITESPACE QUOTE "=" : WHITESPACE QUOTE);
255 	if (*s == NULL)
256 		return (old);
257 
258 	if (*s[0] == '\"') {
259 		memmove(*s, *s + 1, strlen(*s)); /* move nul too */
260 		/* Find matching quote */
261 		if ((*s = strpbrk(*s, QUOTE)) == NULL) {
262 			return (NULL);		/* no matching quote */
263 		} else {
264 			*s[0] = '\0';
265 			*s += strspn(*s + 1, WHITESPACE) + 1;
266 			return (old);
267 		}
268 	}
269 
270 	/* Allow only one '=' to be skipped */
271 	if (split_equals && *s[0] == '=')
272 		wspace = 1;
273 	*s[0] = '\0';
274 
275 	/* Skip any extra whitespace after first token */
276 	*s += strspn(*s + 1, WHITESPACE) + 1;
277 	if (split_equals && *s[0] == '=' && !wspace)
278 		*s += strspn(*s + 1, WHITESPACE) + 1;
279 
280 	return (old);
281 }
282 
283 /*
284  * Return next token in configuration line; splts on whitespace or a
285  * single '=' character.
286  */
287 char *
288 strdelim(char **s)
289 {
290 	return strdelim_internal(s, 1);
291 }
292 
293 /*
294  * Return next token in configuration line; splts on whitespace only.
295  */
296 char *
297 strdelimw(char **s)
298 {
299 	return strdelim_internal(s, 0);
300 }
301 
302 struct passwd *
303 pwcopy(struct passwd *pw)
304 {
305 	struct passwd *copy = xcalloc(1, sizeof(*copy));
306 
307 	copy->pw_name = xstrdup(pw->pw_name);
308 	copy->pw_passwd = xstrdup(pw->pw_passwd);
309 #ifdef HAVE_STRUCT_PASSWD_PW_GECOS
310 	copy->pw_gecos = xstrdup(pw->pw_gecos);
311 #endif
312 	copy->pw_uid = pw->pw_uid;
313 	copy->pw_gid = pw->pw_gid;
314 #ifdef HAVE_STRUCT_PASSWD_PW_EXPIRE
315 	copy->pw_expire = pw->pw_expire;
316 #endif
317 #ifdef HAVE_STRUCT_PASSWD_PW_CHANGE
318 	copy->pw_change = pw->pw_change;
319 #endif
320 #ifdef HAVE_STRUCT_PASSWD_PW_CLASS
321 	copy->pw_class = xstrdup(pw->pw_class);
322 #endif
323 	copy->pw_dir = xstrdup(pw->pw_dir);
324 	copy->pw_shell = xstrdup(pw->pw_shell);
325 	return copy;
326 }
327 
328 /*
329  * Convert ASCII string to TCP/IP port number.
330  * Port must be >=0 and <=65535.
331  * Return -1 if invalid.
332  */
333 int
334 a2port(const char *s)
335 {
336 	struct servent *se;
337 	long long port;
338 	const char *errstr;
339 
340 	port = strtonum(s, 0, 65535, &errstr);
341 	if (errstr == NULL)
342 		return (int)port;
343 	if ((se = getservbyname(s, "tcp")) != NULL)
344 		return ntohs(se->s_port);
345 	return -1;
346 }
347 
348 int
349 a2tun(const char *s, int *remote)
350 {
351 	const char *errstr = NULL;
352 	char *sp, *ep;
353 	int tun;
354 
355 	if (remote != NULL) {
356 		*remote = SSH_TUNID_ANY;
357 		sp = xstrdup(s);
358 		if ((ep = strchr(sp, ':')) == NULL) {
359 			free(sp);
360 			return (a2tun(s, NULL));
361 		}
362 		ep[0] = '\0'; ep++;
363 		*remote = a2tun(ep, NULL);
364 		tun = a2tun(sp, NULL);
365 		free(sp);
366 		return (*remote == SSH_TUNID_ERR ? *remote : tun);
367 	}
368 
369 	if (strcasecmp(s, "any") == 0)
370 		return (SSH_TUNID_ANY);
371 
372 	tun = strtonum(s, 0, SSH_TUNID_MAX, &errstr);
373 	if (errstr != NULL)
374 		return (SSH_TUNID_ERR);
375 
376 	return (tun);
377 }
378 
379 #define SECONDS		1
380 #define MINUTES		(SECONDS * 60)
381 #define HOURS		(MINUTES * 60)
382 #define DAYS		(HOURS * 24)
383 #define WEEKS		(DAYS * 7)
384 
385 /*
386  * Convert a time string into seconds; format is
387  * a sequence of:
388  *      time[qualifier]
389  *
390  * Valid time qualifiers are:
391  *      <none>  seconds
392  *      s|S     seconds
393  *      m|M     minutes
394  *      h|H     hours
395  *      d|D     days
396  *      w|W     weeks
397  *
398  * Examples:
399  *      90m     90 minutes
400  *      1h30m   90 minutes
401  *      2d      2 days
402  *      1w      1 week
403  *
404  * Return -1 if time string is invalid.
405  */
406 long
407 convtime(const char *s)
408 {
409 	long total, secs, multiplier = 1;
410 	const char *p;
411 	char *endp;
412 
413 	errno = 0;
414 	total = 0;
415 	p = s;
416 
417 	if (p == NULL || *p == '\0')
418 		return -1;
419 
420 	while (*p) {
421 		secs = strtol(p, &endp, 10);
422 		if (p == endp ||
423 		    (errno == ERANGE && (secs == LONG_MIN || secs == LONG_MAX)) ||
424 		    secs < 0)
425 			return -1;
426 
427 		switch (*endp++) {
428 		case '\0':
429 			endp--;
430 			break;
431 		case 's':
432 		case 'S':
433 			break;
434 		case 'm':
435 		case 'M':
436 			multiplier = MINUTES;
437 			break;
438 		case 'h':
439 		case 'H':
440 			multiplier = HOURS;
441 			break;
442 		case 'd':
443 		case 'D':
444 			multiplier = DAYS;
445 			break;
446 		case 'w':
447 		case 'W':
448 			multiplier = WEEKS;
449 			break;
450 		default:
451 			return -1;
452 		}
453 		if (secs >= LONG_MAX / multiplier)
454 			return -1;
455 		secs *= multiplier;
456 		if  (total >= LONG_MAX - secs)
457 			return -1;
458 		total += secs;
459 		if (total < 0)
460 			return -1;
461 		p = endp;
462 	}
463 
464 	return total;
465 }
466 
467 /*
468  * Returns a standardized host+port identifier string.
469  * Caller must free returned string.
470  */
471 char *
472 put_host_port(const char *host, u_short port)
473 {
474 	char *hoststr;
475 
476 	if (port == 0 || port == SSH_DEFAULT_PORT)
477 		return(xstrdup(host));
478 	if (asprintf(&hoststr, "[%s]:%d", host, (int)port) < 0)
479 		fatal("put_host_port: asprintf: %s", strerror(errno));
480 	debug3("put_host_port: %s", hoststr);
481 	return hoststr;
482 }
483 
484 /*
485  * Search for next delimiter between hostnames/addresses and ports.
486  * Argument may be modified (for termination).
487  * Returns *cp if parsing succeeds.
488  * *cp is set to the start of the next field, if one was found.
489  * The delimiter char, if present, is stored in delim.
490  * If this is the last field, *cp is set to NULL.
491  */
492 static char *
493 hpdelim2(char **cp, char *delim)
494 {
495 	char *s, *old;
496 
497 	if (cp == NULL || *cp == NULL)
498 		return NULL;
499 
500 	old = s = *cp;
501 	if (*s == '[') {
502 		if ((s = strchr(s, ']')) == NULL)
503 			return NULL;
504 		else
505 			s++;
506 	} else if ((s = strpbrk(s, ":/")) == NULL)
507 		s = *cp + strlen(*cp); /* skip to end (see first case below) */
508 
509 	switch (*s) {
510 	case '\0':
511 		*cp = NULL;	/* no more fields*/
512 		break;
513 
514 	case ':':
515 	case '/':
516 		if (delim != NULL)
517 			*delim = *s;
518 		*s = '\0';	/* terminate */
519 		*cp = s + 1;
520 		break;
521 
522 	default:
523 		return NULL;
524 	}
525 
526 	return old;
527 }
528 
529 char *
530 hpdelim(char **cp)
531 {
532 	return hpdelim2(cp, NULL);
533 }
534 
535 char *
536 cleanhostname(char *host)
537 {
538 	if (*host == '[' && host[strlen(host) - 1] == ']') {
539 		host[strlen(host) - 1] = '\0';
540 		return (host + 1);
541 	} else
542 		return host;
543 }
544 
545 char *
546 colon(char *cp)
547 {
548 	int flag = 0;
549 
550 	if (*cp == ':')		/* Leading colon is part of file name. */
551 		return NULL;
552 	if (*cp == '[')
553 		flag = 1;
554 
555 	for (; *cp; ++cp) {
556 		if (*cp == '@' && *(cp+1) == '[')
557 			flag = 1;
558 		if (*cp == ']' && *(cp+1) == ':' && flag)
559 			return (cp+1);
560 		if (*cp == ':' && !flag)
561 			return (cp);
562 		if (*cp == '/')
563 			return NULL;
564 	}
565 	return NULL;
566 }
567 
568 /*
569  * Parse a [user@]host:[path] string.
570  * Caller must free returned user, host and path.
571  * Any of the pointer return arguments may be NULL (useful for syntax checking).
572  * If user was not specified then *userp will be set to NULL.
573  * If host was not specified then *hostp will be set to NULL.
574  * If path was not specified then *pathp will be set to ".".
575  * Returns 0 on success, -1 on failure.
576  */
577 int
578 parse_user_host_path(const char *s, char **userp, char **hostp, char **pathp)
579 {
580 	char *user = NULL, *host = NULL, *path = NULL;
581 	char *sdup, *tmp;
582 	int ret = -1;
583 
584 	if (userp != NULL)
585 		*userp = NULL;
586 	if (hostp != NULL)
587 		*hostp = NULL;
588 	if (pathp != NULL)
589 		*pathp = NULL;
590 
591 	sdup = xstrdup(s);
592 
593 	/* Check for remote syntax: [user@]host:[path] */
594 	if ((tmp = colon(sdup)) == NULL)
595 		goto out;
596 
597 	/* Extract optional path */
598 	*tmp++ = '\0';
599 	if (*tmp == '\0')
600 		tmp = ".";
601 	path = xstrdup(tmp);
602 
603 	/* Extract optional user and mandatory host */
604 	tmp = strrchr(sdup, '@');
605 	if (tmp != NULL) {
606 		*tmp++ = '\0';
607 		host = xstrdup(cleanhostname(tmp));
608 		if (*sdup != '\0')
609 			user = xstrdup(sdup);
610 	} else {
611 		host = xstrdup(cleanhostname(sdup));
612 		user = NULL;
613 	}
614 
615 	/* Success */
616 	if (userp != NULL) {
617 		*userp = user;
618 		user = NULL;
619 	}
620 	if (hostp != NULL) {
621 		*hostp = host;
622 		host = NULL;
623 	}
624 	if (pathp != NULL) {
625 		*pathp = path;
626 		path = NULL;
627 	}
628 	ret = 0;
629 out:
630 	free(sdup);
631 	free(user);
632 	free(host);
633 	free(path);
634 	return ret;
635 }
636 
637 /*
638  * Parse a [user@]host[:port] string.
639  * Caller must free returned user and host.
640  * Any of the pointer return arguments may be NULL (useful for syntax checking).
641  * If user was not specified then *userp will be set to NULL.
642  * If port was not specified then *portp will be -1.
643  * Returns 0 on success, -1 on failure.
644  */
645 int
646 parse_user_host_port(const char *s, char **userp, char **hostp, int *portp)
647 {
648 	char *sdup, *cp, *tmp;
649 	char *user = NULL, *host = NULL;
650 	int port = -1, ret = -1;
651 
652 	if (userp != NULL)
653 		*userp = NULL;
654 	if (hostp != NULL)
655 		*hostp = NULL;
656 	if (portp != NULL)
657 		*portp = -1;
658 
659 	if ((sdup = tmp = strdup(s)) == NULL)
660 		return -1;
661 	/* Extract optional username */
662 	if ((cp = strrchr(tmp, '@')) != NULL) {
663 		*cp = '\0';
664 		if (*tmp == '\0')
665 			goto out;
666 		if ((user = strdup(tmp)) == NULL)
667 			goto out;
668 		tmp = cp + 1;
669 	}
670 	/* Extract mandatory hostname */
671 	if ((cp = hpdelim(&tmp)) == NULL || *cp == '\0')
672 		goto out;
673 	host = xstrdup(cleanhostname(cp));
674 	/* Convert and verify optional port */
675 	if (tmp != NULL && *tmp != '\0') {
676 		if ((port = a2port(tmp)) <= 0)
677 			goto out;
678 	}
679 	/* Success */
680 	if (userp != NULL) {
681 		*userp = user;
682 		user = NULL;
683 	}
684 	if (hostp != NULL) {
685 		*hostp = host;
686 		host = NULL;
687 	}
688 	if (portp != NULL)
689 		*portp = port;
690 	ret = 0;
691  out:
692 	free(sdup);
693 	free(user);
694 	free(host);
695 	return ret;
696 }
697 
698 /*
699  * Converts a two-byte hex string to decimal.
700  * Returns the decimal value or -1 for invalid input.
701  */
702 static int
703 hexchar(const char *s)
704 {
705 	unsigned char result[2];
706 	int i;
707 
708 	for (i = 0; i < 2; i++) {
709 		if (s[i] >= '0' && s[i] <= '9')
710 			result[i] = (unsigned char)(s[i] - '0');
711 		else if (s[i] >= 'a' && s[i] <= 'f')
712 			result[i] = (unsigned char)(s[i] - 'a') + 10;
713 		else if (s[i] >= 'A' && s[i] <= 'F')
714 			result[i] = (unsigned char)(s[i] - 'A') + 10;
715 		else
716 			return -1;
717 	}
718 	return (result[0] << 4) | result[1];
719 }
720 
721 /*
722  * Decode an url-encoded string.
723  * Returns a newly allocated string on success or NULL on failure.
724  */
725 static char *
726 urldecode(const char *src)
727 {
728 	char *ret, *dst;
729 	int ch;
730 
731 	ret = xmalloc(strlen(src) + 1);
732 	for (dst = ret; *src != '\0'; src++) {
733 		switch (*src) {
734 		case '+':
735 			*dst++ = ' ';
736 			break;
737 		case '%':
738 			if (!isxdigit((unsigned char)src[1]) ||
739 			    !isxdigit((unsigned char)src[2]) ||
740 			    (ch = hexchar(src + 1)) == -1) {
741 				free(ret);
742 				return NULL;
743 			}
744 			*dst++ = ch;
745 			src += 2;
746 			break;
747 		default:
748 			*dst++ = *src;
749 			break;
750 		}
751 	}
752 	*dst = '\0';
753 
754 	return ret;
755 }
756 
757 /*
758  * Parse an (scp|ssh|sftp)://[user@]host[:port][/path] URI.
759  * See https://tools.ietf.org/html/draft-ietf-secsh-scp-sftp-ssh-uri-04
760  * Either user or path may be url-encoded (but not host or port).
761  * Caller must free returned user, host and path.
762  * Any of the pointer return arguments may be NULL (useful for syntax checking)
763  * but the scheme must always be specified.
764  * If user was not specified then *userp will be set to NULL.
765  * If port was not specified then *portp will be -1.
766  * If path was not specified then *pathp will be set to NULL.
767  * Returns 0 on success, 1 if non-uri/wrong scheme, -1 on error/invalid uri.
768  */
769 int
770 parse_uri(const char *scheme, const char *uri, char **userp, char **hostp,
771     int *portp, char **pathp)
772 {
773 	char *uridup, *cp, *tmp, ch;
774 	char *user = NULL, *host = NULL, *path = NULL;
775 	int port = -1, ret = -1;
776 	size_t len;
777 
778 	len = strlen(scheme);
779 	if (strncmp(uri, scheme, len) != 0 || strncmp(uri + len, "://", 3) != 0)
780 		return 1;
781 	uri += len + 3;
782 
783 	if (userp != NULL)
784 		*userp = NULL;
785 	if (hostp != NULL)
786 		*hostp = NULL;
787 	if (portp != NULL)
788 		*portp = -1;
789 	if (pathp != NULL)
790 		*pathp = NULL;
791 
792 	uridup = tmp = xstrdup(uri);
793 
794 	/* Extract optional ssh-info (username + connection params) */
795 	if ((cp = strchr(tmp, '@')) != NULL) {
796 		char *delim;
797 
798 		*cp = '\0';
799 		/* Extract username and connection params */
800 		if ((delim = strchr(tmp, ';')) != NULL) {
801 			/* Just ignore connection params for now */
802 			*delim = '\0';
803 		}
804 		if (*tmp == '\0') {
805 			/* Empty username */
806 			goto out;
807 		}
808 		if ((user = urldecode(tmp)) == NULL)
809 			goto out;
810 		tmp = cp + 1;
811 	}
812 
813 	/* Extract mandatory hostname */
814 	if ((cp = hpdelim2(&tmp, &ch)) == NULL || *cp == '\0')
815 		goto out;
816 	host = xstrdup(cleanhostname(cp));
817 	if (!valid_domain(host, 0, NULL))
818 		goto out;
819 
820 	if (tmp != NULL && *tmp != '\0') {
821 		if (ch == ':') {
822 			/* Convert and verify port. */
823 			if ((cp = strchr(tmp, '/')) != NULL)
824 				*cp = '\0';
825 			if ((port = a2port(tmp)) <= 0)
826 				goto out;
827 			tmp = cp ? cp + 1 : NULL;
828 		}
829 		if (tmp != NULL && *tmp != '\0') {
830 			/* Extract optional path */
831 			if ((path = urldecode(tmp)) == NULL)
832 				goto out;
833 		}
834 	}
835 
836 	/* Success */
837 	if (userp != NULL) {
838 		*userp = user;
839 		user = NULL;
840 	}
841 	if (hostp != NULL) {
842 		*hostp = host;
843 		host = NULL;
844 	}
845 	if (portp != NULL)
846 		*portp = port;
847 	if (pathp != NULL) {
848 		*pathp = path;
849 		path = NULL;
850 	}
851 	ret = 0;
852  out:
853 	free(uridup);
854 	free(user);
855 	free(host);
856 	free(path);
857 	return ret;
858 }
859 
860 /* function to assist building execv() arguments */
861 void
862 addargs(arglist *args, char *fmt, ...)
863 {
864 	va_list ap;
865 	char *cp;
866 	u_int nalloc;
867 	int r;
868 
869 	va_start(ap, fmt);
870 	r = vasprintf(&cp, fmt, ap);
871 	va_end(ap);
872 	if (r == -1)
873 		fatal("addargs: argument too long");
874 
875 	nalloc = args->nalloc;
876 	if (args->list == NULL) {
877 		nalloc = 32;
878 		args->num = 0;
879 	} else if (args->num+2 >= nalloc)
880 		nalloc *= 2;
881 
882 	args->list = xrecallocarray(args->list, args->nalloc, nalloc, sizeof(char *));
883 	args->nalloc = nalloc;
884 	args->list[args->num++] = cp;
885 	args->list[args->num] = NULL;
886 }
887 
888 void
889 replacearg(arglist *args, u_int which, char *fmt, ...)
890 {
891 	va_list ap;
892 	char *cp;
893 	int r;
894 
895 	va_start(ap, fmt);
896 	r = vasprintf(&cp, fmt, ap);
897 	va_end(ap);
898 	if (r == -1)
899 		fatal("replacearg: argument too long");
900 
901 	if (which >= args->num)
902 		fatal("replacearg: tried to replace invalid arg %d >= %d",
903 		    which, args->num);
904 	free(args->list[which]);
905 	args->list[which] = cp;
906 }
907 
908 void
909 freeargs(arglist *args)
910 {
911 	u_int i;
912 
913 	if (args->list != NULL) {
914 		for (i = 0; i < args->num; i++)
915 			free(args->list[i]);
916 		free(args->list);
917 		args->nalloc = args->num = 0;
918 		args->list = NULL;
919 	}
920 }
921 
922 /*
923  * Expands tildes in the file name.  Returns data allocated by xmalloc.
924  * Warning: this calls getpw*.
925  */
926 char *
927 tilde_expand_filename(const char *filename, uid_t uid)
928 {
929 	const char *path, *sep;
930 	char user[128], *ret;
931 	struct passwd *pw;
932 	u_int len, slash;
933 
934 	if (*filename != '~')
935 		return (xstrdup(filename));
936 	filename++;
937 
938 	path = strchr(filename, '/');
939 	if (path != NULL && path > filename) {		/* ~user/path */
940 		slash = path - filename;
941 		if (slash > sizeof(user) - 1)
942 			fatal("tilde_expand_filename: ~username too long");
943 		memcpy(user, filename, slash);
944 		user[slash] = '\0';
945 		if ((pw = getpwnam(user)) == NULL)
946 			fatal("tilde_expand_filename: No such user %s", user);
947 	} else if ((pw = getpwuid(uid)) == NULL)	/* ~/path */
948 		fatal("tilde_expand_filename: No such uid %ld", (long)uid);
949 
950 	/* Make sure directory has a trailing '/' */
951 	len = strlen(pw->pw_dir);
952 	if (len == 0 || pw->pw_dir[len - 1] != '/')
953 		sep = "/";
954 	else
955 		sep = "";
956 
957 	/* Skip leading '/' from specified path */
958 	if (path != NULL)
959 		filename = path + 1;
960 
961 	if (xasprintf(&ret, "%s%s%s", pw->pw_dir, sep, filename) >= PATH_MAX)
962 		fatal("tilde_expand_filename: Path too long");
963 
964 	return (ret);
965 }
966 
967 /*
968  * Expand a string with a set of %[char] escapes. A number of escapes may be
969  * specified as (char *escape_chars, char *replacement) pairs. The list must
970  * be terminated by a NULL escape_char. Returns replaced string in memory
971  * allocated by xmalloc.
972  */
973 char *
974 percent_expand(const char *string, ...)
975 {
976 #define EXPAND_MAX_KEYS	16
977 	u_int num_keys, i, j;
978 	struct {
979 		const char *key;
980 		const char *repl;
981 	} keys[EXPAND_MAX_KEYS];
982 	char buf[4096];
983 	va_list ap;
984 
985 	/* Gather keys */
986 	va_start(ap, string);
987 	for (num_keys = 0; num_keys < EXPAND_MAX_KEYS; num_keys++) {
988 		keys[num_keys].key = va_arg(ap, char *);
989 		if (keys[num_keys].key == NULL)
990 			break;
991 		keys[num_keys].repl = va_arg(ap, char *);
992 		if (keys[num_keys].repl == NULL)
993 			fatal("%s: NULL replacement", __func__);
994 	}
995 	if (num_keys == EXPAND_MAX_KEYS && va_arg(ap, char *) != NULL)
996 		fatal("%s: too many keys", __func__);
997 	va_end(ap);
998 
999 	/* Expand string */
1000 	*buf = '\0';
1001 	for (i = 0; *string != '\0'; string++) {
1002 		if (*string != '%') {
1003  append:
1004 			buf[i++] = *string;
1005 			if (i >= sizeof(buf))
1006 				fatal("%s: string too long", __func__);
1007 			buf[i] = '\0';
1008 			continue;
1009 		}
1010 		string++;
1011 		/* %% case */
1012 		if (*string == '%')
1013 			goto append;
1014 		if (*string == '\0')
1015 			fatal("%s: invalid format", __func__);
1016 		for (j = 0; j < num_keys; j++) {
1017 			if (strchr(keys[j].key, *string) != NULL) {
1018 				i = strlcat(buf, keys[j].repl, sizeof(buf));
1019 				if (i >= sizeof(buf))
1020 					fatal("%s: string too long", __func__);
1021 				break;
1022 			}
1023 		}
1024 		if (j >= num_keys)
1025 			fatal("%s: unknown key %%%c", __func__, *string);
1026 	}
1027 	return (xstrdup(buf));
1028 #undef EXPAND_MAX_KEYS
1029 }
1030 
1031 int
1032 tun_open(int tun, int mode, char **ifname)
1033 {
1034 #if defined(CUSTOM_SYS_TUN_OPEN)
1035 	return (sys_tun_open(tun, mode, ifname));
1036 #elif defined(SSH_TUN_OPENBSD)
1037 	struct ifreq ifr;
1038 	char name[100];
1039 	int fd = -1, sock;
1040 	const char *tunbase = "tun";
1041 
1042 	if (ifname != NULL)
1043 		*ifname = NULL;
1044 
1045 	if (mode == SSH_TUNMODE_ETHERNET)
1046 		tunbase = "tap";
1047 
1048 	/* Open the tunnel device */
1049 	if (tun <= SSH_TUNID_MAX) {
1050 		snprintf(name, sizeof(name), "/dev/%s%d", tunbase, tun);
1051 		fd = open(name, O_RDWR);
1052 	} else if (tun == SSH_TUNID_ANY) {
1053 		for (tun = 100; tun >= 0; tun--) {
1054 			snprintf(name, sizeof(name), "/dev/%s%d",
1055 			    tunbase, tun);
1056 			if ((fd = open(name, O_RDWR)) >= 0)
1057 				break;
1058 		}
1059 	} else {
1060 		debug("%s: invalid tunnel %u", __func__, tun);
1061 		return -1;
1062 	}
1063 
1064 	if (fd < 0) {
1065 		debug("%s: %s open: %s", __func__, name, strerror(errno));
1066 		return -1;
1067 	}
1068 
1069 	debug("%s: %s mode %d fd %d", __func__, name, mode, fd);
1070 
1071 	/* Bring interface up if it is not already */
1072 	snprintf(ifr.ifr_name, sizeof(ifr.ifr_name), "%s%d", tunbase, tun);
1073 	if ((sock = socket(PF_UNIX, SOCK_STREAM, 0)) == -1)
1074 		goto failed;
1075 
1076 	if (ioctl(sock, SIOCGIFFLAGS, &ifr) == -1) {
1077 		debug("%s: get interface %s flags: %s", __func__,
1078 		    ifr.ifr_name, strerror(errno));
1079 		goto failed;
1080 	}
1081 
1082 	if (!(ifr.ifr_flags & IFF_UP)) {
1083 		ifr.ifr_flags |= IFF_UP;
1084 		if (ioctl(sock, SIOCSIFFLAGS, &ifr) == -1) {
1085 			debug("%s: activate interface %s: %s", __func__,
1086 			    ifr.ifr_name, strerror(errno));
1087 			goto failed;
1088 		}
1089 	}
1090 
1091 	if (ifname != NULL)
1092 		*ifname = xstrdup(ifr.ifr_name);
1093 
1094 	close(sock);
1095 	return fd;
1096 
1097  failed:
1098 	if (fd >= 0)
1099 		close(fd);
1100 	if (sock >= 0)
1101 		close(sock);
1102 	return -1;
1103 #else
1104 	error("Tunnel interfaces are not supported on this platform");
1105 	return (-1);
1106 #endif
1107 }
1108 
1109 void
1110 sanitise_stdfd(void)
1111 {
1112 	int nullfd, dupfd;
1113 
1114 	if ((nullfd = dupfd = open(_PATH_DEVNULL, O_RDWR)) == -1) {
1115 		fprintf(stderr, "Couldn't open /dev/null: %s\n",
1116 		    strerror(errno));
1117 		exit(1);
1118 	}
1119 	while (++dupfd <= STDERR_FILENO) {
1120 		/* Only populate closed fds. */
1121 		if (fcntl(dupfd, F_GETFL) == -1 && errno == EBADF) {
1122 			if (dup2(nullfd, dupfd) == -1) {
1123 				fprintf(stderr, "dup2: %s\n", strerror(errno));
1124 				exit(1);
1125 			}
1126 		}
1127 	}
1128 	if (nullfd > STDERR_FILENO)
1129 		close(nullfd);
1130 }
1131 
1132 char *
1133 tohex(const void *vp, size_t l)
1134 {
1135 	const u_char *p = (const u_char *)vp;
1136 	char b[3], *r;
1137 	size_t i, hl;
1138 
1139 	if (l > 65536)
1140 		return xstrdup("tohex: length > 65536");
1141 
1142 	hl = l * 2 + 1;
1143 	r = xcalloc(1, hl);
1144 	for (i = 0; i < l; i++) {
1145 		snprintf(b, sizeof(b), "%02x", p[i]);
1146 		strlcat(r, b, hl);
1147 	}
1148 	return (r);
1149 }
1150 
1151 u_int64_t
1152 get_u64(const void *vp)
1153 {
1154 	const u_char *p = (const u_char *)vp;
1155 	u_int64_t v;
1156 
1157 	v  = (u_int64_t)p[0] << 56;
1158 	v |= (u_int64_t)p[1] << 48;
1159 	v |= (u_int64_t)p[2] << 40;
1160 	v |= (u_int64_t)p[3] << 32;
1161 	v |= (u_int64_t)p[4] << 24;
1162 	v |= (u_int64_t)p[5] << 16;
1163 	v |= (u_int64_t)p[6] << 8;
1164 	v |= (u_int64_t)p[7];
1165 
1166 	return (v);
1167 }
1168 
1169 u_int32_t
1170 get_u32(const void *vp)
1171 {
1172 	const u_char *p = (const u_char *)vp;
1173 	u_int32_t v;
1174 
1175 	v  = (u_int32_t)p[0] << 24;
1176 	v |= (u_int32_t)p[1] << 16;
1177 	v |= (u_int32_t)p[2] << 8;
1178 	v |= (u_int32_t)p[3];
1179 
1180 	return (v);
1181 }
1182 
1183 u_int32_t
1184 get_u32_le(const void *vp)
1185 {
1186 	const u_char *p = (const u_char *)vp;
1187 	u_int32_t v;
1188 
1189 	v  = (u_int32_t)p[0];
1190 	v |= (u_int32_t)p[1] << 8;
1191 	v |= (u_int32_t)p[2] << 16;
1192 	v |= (u_int32_t)p[3] << 24;
1193 
1194 	return (v);
1195 }
1196 
1197 u_int16_t
1198 get_u16(const void *vp)
1199 {
1200 	const u_char *p = (const u_char *)vp;
1201 	u_int16_t v;
1202 
1203 	v  = (u_int16_t)p[0] << 8;
1204 	v |= (u_int16_t)p[1];
1205 
1206 	return (v);
1207 }
1208 
1209 void
1210 put_u64(void *vp, u_int64_t v)
1211 {
1212 	u_char *p = (u_char *)vp;
1213 
1214 	p[0] = (u_char)(v >> 56) & 0xff;
1215 	p[1] = (u_char)(v >> 48) & 0xff;
1216 	p[2] = (u_char)(v >> 40) & 0xff;
1217 	p[3] = (u_char)(v >> 32) & 0xff;
1218 	p[4] = (u_char)(v >> 24) & 0xff;
1219 	p[5] = (u_char)(v >> 16) & 0xff;
1220 	p[6] = (u_char)(v >> 8) & 0xff;
1221 	p[7] = (u_char)v & 0xff;
1222 }
1223 
1224 void
1225 put_u32(void *vp, u_int32_t v)
1226 {
1227 	u_char *p = (u_char *)vp;
1228 
1229 	p[0] = (u_char)(v >> 24) & 0xff;
1230 	p[1] = (u_char)(v >> 16) & 0xff;
1231 	p[2] = (u_char)(v >> 8) & 0xff;
1232 	p[3] = (u_char)v & 0xff;
1233 }
1234 
1235 void
1236 put_u32_le(void *vp, u_int32_t v)
1237 {
1238 	u_char *p = (u_char *)vp;
1239 
1240 	p[0] = (u_char)v & 0xff;
1241 	p[1] = (u_char)(v >> 8) & 0xff;
1242 	p[2] = (u_char)(v >> 16) & 0xff;
1243 	p[3] = (u_char)(v >> 24) & 0xff;
1244 }
1245 
1246 void
1247 put_u16(void *vp, u_int16_t v)
1248 {
1249 	u_char *p = (u_char *)vp;
1250 
1251 	p[0] = (u_char)(v >> 8) & 0xff;
1252 	p[1] = (u_char)v & 0xff;
1253 }
1254 
1255 void
1256 ms_subtract_diff(struct timeval *start, int *ms)
1257 {
1258 	struct timeval diff, finish;
1259 
1260 	monotime_tv(&finish);
1261 	timersub(&finish, start, &diff);
1262 	*ms -= (diff.tv_sec * 1000) + (diff.tv_usec / 1000);
1263 }
1264 
1265 void
1266 ms_to_timeval(struct timeval *tv, int ms)
1267 {
1268 	if (ms < 0)
1269 		ms = 0;
1270 	tv->tv_sec = ms / 1000;
1271 	tv->tv_usec = (ms % 1000) * 1000;
1272 }
1273 
1274 void
1275 monotime_ts(struct timespec *ts)
1276 {
1277 	struct timeval tv;
1278 #if defined(HAVE_CLOCK_GETTIME) && (defined(CLOCK_BOOTTIME) || \
1279     defined(CLOCK_MONOTONIC) || defined(CLOCK_REALTIME))
1280 	static int gettime_failed = 0;
1281 
1282 	if (!gettime_failed) {
1283 # ifdef CLOCK_BOOTTIME
1284 		if (clock_gettime(CLOCK_BOOTTIME, ts) == 0)
1285 			return;
1286 # endif /* CLOCK_BOOTTIME */
1287 # ifdef CLOCK_MONOTONIC
1288 		if (clock_gettime(CLOCK_MONOTONIC, ts) == 0)
1289 			return;
1290 # endif /* CLOCK_MONOTONIC */
1291 # ifdef CLOCK_REALTIME
1292 		/* Not monotonic, but we're almost out of options here. */
1293 		if (clock_gettime(CLOCK_REALTIME, ts) == 0)
1294 			return;
1295 # endif /* CLOCK_REALTIME */
1296 		debug3("clock_gettime: %s", strerror(errno));
1297 		gettime_failed = 1;
1298 	}
1299 #endif /* HAVE_CLOCK_GETTIME && (BOOTTIME || MONOTONIC || REALTIME) */
1300 	gettimeofday(&tv, NULL);
1301 	ts->tv_sec = tv.tv_sec;
1302 	ts->tv_nsec = (long)tv.tv_usec * 1000;
1303 }
1304 
1305 void
1306 monotime_tv(struct timeval *tv)
1307 {
1308 	struct timespec ts;
1309 
1310 	monotime_ts(&ts);
1311 	tv->tv_sec = ts.tv_sec;
1312 	tv->tv_usec = ts.tv_nsec / 1000;
1313 }
1314 
1315 time_t
1316 monotime(void)
1317 {
1318 	struct timespec ts;
1319 
1320 	monotime_ts(&ts);
1321 	return ts.tv_sec;
1322 }
1323 
1324 double
1325 monotime_double(void)
1326 {
1327 	struct timespec ts;
1328 
1329 	monotime_ts(&ts);
1330 	return ts.tv_sec + ((double)ts.tv_nsec / 1000000000);
1331 }
1332 
1333 void
1334 bandwidth_limit_init(struct bwlimit *bw, u_int64_t kbps, size_t buflen)
1335 {
1336 	bw->buflen = buflen;
1337 	bw->rate = kbps;
1338 	bw->thresh = bw->rate;
1339 	bw->lamt = 0;
1340 	timerclear(&bw->bwstart);
1341 	timerclear(&bw->bwend);
1342 }
1343 
1344 /* Callback from read/write loop to insert bandwidth-limiting delays */
1345 void
1346 bandwidth_limit(struct bwlimit *bw, size_t read_len)
1347 {
1348 	u_int64_t waitlen;
1349 	struct timespec ts, rm;
1350 
1351 	if (!timerisset(&bw->bwstart)) {
1352 		monotime_tv(&bw->bwstart);
1353 		return;
1354 	}
1355 
1356 	bw->lamt += read_len;
1357 	if (bw->lamt < bw->thresh)
1358 		return;
1359 
1360 	monotime_tv(&bw->bwend);
1361 	timersub(&bw->bwend, &bw->bwstart, &bw->bwend);
1362 	if (!timerisset(&bw->bwend))
1363 		return;
1364 
1365 	bw->lamt *= 8;
1366 	waitlen = (double)1000000L * bw->lamt / bw->rate;
1367 
1368 	bw->bwstart.tv_sec = waitlen / 1000000L;
1369 	bw->bwstart.tv_usec = waitlen % 1000000L;
1370 
1371 	if (timercmp(&bw->bwstart, &bw->bwend, >)) {
1372 		timersub(&bw->bwstart, &bw->bwend, &bw->bwend);
1373 
1374 		/* Adjust the wait time */
1375 		if (bw->bwend.tv_sec) {
1376 			bw->thresh /= 2;
1377 			if (bw->thresh < bw->buflen / 4)
1378 				bw->thresh = bw->buflen / 4;
1379 		} else if (bw->bwend.tv_usec < 10000) {
1380 			bw->thresh *= 2;
1381 			if (bw->thresh > bw->buflen * 8)
1382 				bw->thresh = bw->buflen * 8;
1383 		}
1384 
1385 		TIMEVAL_TO_TIMESPEC(&bw->bwend, &ts);
1386 		while (nanosleep(&ts, &rm) == -1) {
1387 			if (errno != EINTR)
1388 				break;
1389 			ts = rm;
1390 		}
1391 	}
1392 
1393 	bw->lamt = 0;
1394 	monotime_tv(&bw->bwstart);
1395 }
1396 
1397 /* Make a template filename for mk[sd]temp() */
1398 void
1399 mktemp_proto(char *s, size_t len)
1400 {
1401 	const char *tmpdir;
1402 	int r;
1403 
1404 	if ((tmpdir = getenv("TMPDIR")) != NULL) {
1405 		r = snprintf(s, len, "%s/ssh-XXXXXXXXXXXX", tmpdir);
1406 		if (r > 0 && (size_t)r < len)
1407 			return;
1408 	}
1409 	r = snprintf(s, len, "/tmp/ssh-XXXXXXXXXXXX");
1410 	if (r < 0 || (size_t)r >= len)
1411 		fatal("%s: template string too short", __func__);
1412 }
1413 
1414 static const struct {
1415 	const char *name;
1416 	int value;
1417 } ipqos[] = {
1418 	{ "none", INT_MAX },		/* can't use 0 here; that's CS0 */
1419 	{ "af11", IPTOS_DSCP_AF11 },
1420 	{ "af12", IPTOS_DSCP_AF12 },
1421 	{ "af13", IPTOS_DSCP_AF13 },
1422 	{ "af21", IPTOS_DSCP_AF21 },
1423 	{ "af22", IPTOS_DSCP_AF22 },
1424 	{ "af23", IPTOS_DSCP_AF23 },
1425 	{ "af31", IPTOS_DSCP_AF31 },
1426 	{ "af32", IPTOS_DSCP_AF32 },
1427 	{ "af33", IPTOS_DSCP_AF33 },
1428 	{ "af41", IPTOS_DSCP_AF41 },
1429 	{ "af42", IPTOS_DSCP_AF42 },
1430 	{ "af43", IPTOS_DSCP_AF43 },
1431 	{ "cs0", IPTOS_DSCP_CS0 },
1432 	{ "cs1", IPTOS_DSCP_CS1 },
1433 	{ "cs2", IPTOS_DSCP_CS2 },
1434 	{ "cs3", IPTOS_DSCP_CS3 },
1435 	{ "cs4", IPTOS_DSCP_CS4 },
1436 	{ "cs5", IPTOS_DSCP_CS5 },
1437 	{ "cs6", IPTOS_DSCP_CS6 },
1438 	{ "cs7", IPTOS_DSCP_CS7 },
1439 	{ "ef", IPTOS_DSCP_EF },
1440 	{ "lowdelay", IPTOS_LOWDELAY },
1441 	{ "throughput", IPTOS_THROUGHPUT },
1442 	{ "reliability", IPTOS_RELIABILITY },
1443 	{ NULL, -1 }
1444 };
1445 
1446 int
1447 parse_ipqos(const char *cp)
1448 {
1449 	u_int i;
1450 	char *ep;
1451 	long val;
1452 
1453 	if (cp == NULL)
1454 		return -1;
1455 	for (i = 0; ipqos[i].name != NULL; i++) {
1456 		if (strcasecmp(cp, ipqos[i].name) == 0)
1457 			return ipqos[i].value;
1458 	}
1459 	/* Try parsing as an integer */
1460 	val = strtol(cp, &ep, 0);
1461 	if (*cp == '\0' || *ep != '\0' || val < 0 || val > 255)
1462 		return -1;
1463 	return val;
1464 }
1465 
1466 const char *
1467 iptos2str(int iptos)
1468 {
1469 	int i;
1470 	static char iptos_str[sizeof "0xff"];
1471 
1472 	for (i = 0; ipqos[i].name != NULL; i++) {
1473 		if (ipqos[i].value == iptos)
1474 			return ipqos[i].name;
1475 	}
1476 	snprintf(iptos_str, sizeof iptos_str, "0x%02x", iptos);
1477 	return iptos_str;
1478 }
1479 
1480 void
1481 lowercase(char *s)
1482 {
1483 	for (; *s; s++)
1484 		*s = tolower((u_char)*s);
1485 }
1486 
1487 int
1488 unix_listener(const char *path, int backlog, int unlink_first)
1489 {
1490 	struct sockaddr_un sunaddr;
1491 	int saved_errno, sock;
1492 
1493 	memset(&sunaddr, 0, sizeof(sunaddr));
1494 	sunaddr.sun_family = AF_UNIX;
1495 	if (strlcpy(sunaddr.sun_path, path,
1496 	    sizeof(sunaddr.sun_path)) >= sizeof(sunaddr.sun_path)) {
1497 		error("%s: path \"%s\" too long for Unix domain socket",
1498 		    __func__, path);
1499 		errno = ENAMETOOLONG;
1500 		return -1;
1501 	}
1502 
1503 	sock = socket(PF_UNIX, SOCK_STREAM, 0);
1504 	if (sock < 0) {
1505 		saved_errno = errno;
1506 		error("%s: socket: %.100s", __func__, strerror(errno));
1507 		errno = saved_errno;
1508 		return -1;
1509 	}
1510 	if (unlink_first == 1) {
1511 		if (unlink(path) != 0 && errno != ENOENT)
1512 			error("unlink(%s): %.100s", path, strerror(errno));
1513 	}
1514 	if (bind(sock, (struct sockaddr *)&sunaddr, sizeof(sunaddr)) < 0) {
1515 		saved_errno = errno;
1516 		error("%s: cannot bind to path %s: %s",
1517 		    __func__, path, strerror(errno));
1518 		close(sock);
1519 		errno = saved_errno;
1520 		return -1;
1521 	}
1522 	if (listen(sock, backlog) < 0) {
1523 		saved_errno = errno;
1524 		error("%s: cannot listen on path %s: %s",
1525 		    __func__, path, strerror(errno));
1526 		close(sock);
1527 		unlink(path);
1528 		errno = saved_errno;
1529 		return -1;
1530 	}
1531 	return sock;
1532 }
1533 
1534 void
1535 sock_set_v6only(int s)
1536 {
1537 #if defined(IPV6_V6ONLY) && !defined(__OpenBSD__)
1538 	int on = 1;
1539 
1540 	debug3("%s: set socket %d IPV6_V6ONLY", __func__, s);
1541 	if (setsockopt(s, IPPROTO_IPV6, IPV6_V6ONLY, &on, sizeof(on)) == -1)
1542 		error("setsockopt IPV6_V6ONLY: %s", strerror(errno));
1543 #endif
1544 }
1545 
1546 /*
1547  * Compares two strings that maybe be NULL. Returns non-zero if strings
1548  * are both NULL or are identical, returns zero otherwise.
1549  */
1550 static int
1551 strcmp_maybe_null(const char *a, const char *b)
1552 {
1553 	if ((a == NULL && b != NULL) || (a != NULL && b == NULL))
1554 		return 0;
1555 	if (a != NULL && strcmp(a, b) != 0)
1556 		return 0;
1557 	return 1;
1558 }
1559 
1560 /*
1561  * Compare two forwards, returning non-zero if they are identical or
1562  * zero otherwise.
1563  */
1564 int
1565 forward_equals(const struct Forward *a, const struct Forward *b)
1566 {
1567 	if (strcmp_maybe_null(a->listen_host, b->listen_host) == 0)
1568 		return 0;
1569 	if (a->listen_port != b->listen_port)
1570 		return 0;
1571 	if (strcmp_maybe_null(a->listen_path, b->listen_path) == 0)
1572 		return 0;
1573 	if (strcmp_maybe_null(a->connect_host, b->connect_host) == 0)
1574 		return 0;
1575 	if (a->connect_port != b->connect_port)
1576 		return 0;
1577 	if (strcmp_maybe_null(a->connect_path, b->connect_path) == 0)
1578 		return 0;
1579 	/* allocated_port and handle are not checked */
1580 	return 1;
1581 }
1582 
1583 /* returns 1 if process is already daemonized, 0 otherwise */
1584 int
1585 daemonized(void)
1586 {
1587 	int fd;
1588 
1589 	if ((fd = open(_PATH_TTY, O_RDONLY | O_NOCTTY)) >= 0) {
1590 		close(fd);
1591 		return 0;	/* have controlling terminal */
1592 	}
1593 	if (getppid() != 1)
1594 		return 0;	/* parent is not init */
1595 	if (getsid(0) != getpid())
1596 		return 0;	/* not session leader */
1597 	debug3("already daemonized");
1598 	return 1;
1599 }
1600 
1601 
1602 /*
1603  * Splits 's' into an argument vector. Handles quoted string and basic
1604  * escape characters (\\, \", \'). Caller must free the argument vector
1605  * and its members.
1606  */
1607 int
1608 argv_split(const char *s, int *argcp, char ***argvp)
1609 {
1610 	int r = SSH_ERR_INTERNAL_ERROR;
1611 	int argc = 0, quote, i, j;
1612 	char *arg, **argv = xcalloc(1, sizeof(*argv));
1613 
1614 	*argvp = NULL;
1615 	*argcp = 0;
1616 
1617 	for (i = 0; s[i] != '\0'; i++) {
1618 		/* Skip leading whitespace */
1619 		if (s[i] == ' ' || s[i] == '\t')
1620 			continue;
1621 
1622 		/* Start of a token */
1623 		quote = 0;
1624 		if (s[i] == '\\' &&
1625 		    (s[i + 1] == '\'' || s[i + 1] == '\"' || s[i + 1] == '\\'))
1626 			i++;
1627 		else if (s[i] == '\'' || s[i] == '"')
1628 			quote = s[i++];
1629 
1630 		argv = xreallocarray(argv, (argc + 2), sizeof(*argv));
1631 		arg = argv[argc++] = xcalloc(1, strlen(s + i) + 1);
1632 		argv[argc] = NULL;
1633 
1634 		/* Copy the token in, removing escapes */
1635 		for (j = 0; s[i] != '\0'; i++) {
1636 			if (s[i] == '\\') {
1637 				if (s[i + 1] == '\'' ||
1638 				    s[i + 1] == '\"' ||
1639 				    s[i + 1] == '\\') {
1640 					i++; /* Skip '\' */
1641 					arg[j++] = s[i];
1642 				} else {
1643 					/* Unrecognised escape */
1644 					arg[j++] = s[i];
1645 				}
1646 			} else if (quote == 0 && (s[i] == ' ' || s[i] == '\t'))
1647 				break; /* done */
1648 			else if (quote != 0 && s[i] == quote)
1649 				break; /* done */
1650 			else
1651 				arg[j++] = s[i];
1652 		}
1653 		if (s[i] == '\0') {
1654 			if (quote != 0) {
1655 				/* Ran out of string looking for close quote */
1656 				r = SSH_ERR_INVALID_FORMAT;
1657 				goto out;
1658 			}
1659 			break;
1660 		}
1661 	}
1662 	/* Success */
1663 	*argcp = argc;
1664 	*argvp = argv;
1665 	argc = 0;
1666 	argv = NULL;
1667 	r = 0;
1668  out:
1669 	if (argc != 0 && argv != NULL) {
1670 		for (i = 0; i < argc; i++)
1671 			free(argv[i]);
1672 		free(argv);
1673 	}
1674 	return r;
1675 }
1676 
1677 /*
1678  * Reassemble an argument vector into a string, quoting and escaping as
1679  * necessary. Caller must free returned string.
1680  */
1681 char *
1682 argv_assemble(int argc, char **argv)
1683 {
1684 	int i, j, ws, r;
1685 	char c, *ret;
1686 	struct sshbuf *buf, *arg;
1687 
1688 	if ((buf = sshbuf_new()) == NULL || (arg = sshbuf_new()) == NULL)
1689 		fatal("%s: sshbuf_new failed", __func__);
1690 
1691 	for (i = 0; i < argc; i++) {
1692 		ws = 0;
1693 		sshbuf_reset(arg);
1694 		for (j = 0; argv[i][j] != '\0'; j++) {
1695 			r = 0;
1696 			c = argv[i][j];
1697 			switch (c) {
1698 			case ' ':
1699 			case '\t':
1700 				ws = 1;
1701 				r = sshbuf_put_u8(arg, c);
1702 				break;
1703 			case '\\':
1704 			case '\'':
1705 			case '"':
1706 				if ((r = sshbuf_put_u8(arg, '\\')) != 0)
1707 					break;
1708 				/* FALLTHROUGH */
1709 			default:
1710 				r = sshbuf_put_u8(arg, c);
1711 				break;
1712 			}
1713 			if (r != 0)
1714 				fatal("%s: sshbuf_put_u8: %s",
1715 				    __func__, ssh_err(r));
1716 		}
1717 		if ((i != 0 && (r = sshbuf_put_u8(buf, ' ')) != 0) ||
1718 		    (ws != 0 && (r = sshbuf_put_u8(buf, '"')) != 0) ||
1719 		    (r = sshbuf_putb(buf, arg)) != 0 ||
1720 		    (ws != 0 && (r = sshbuf_put_u8(buf, '"')) != 0))
1721 			fatal("%s: buffer error: %s", __func__, ssh_err(r));
1722 	}
1723 	if ((ret = malloc(sshbuf_len(buf) + 1)) == NULL)
1724 		fatal("%s: malloc failed", __func__);
1725 	memcpy(ret, sshbuf_ptr(buf), sshbuf_len(buf));
1726 	ret[sshbuf_len(buf)] = '\0';
1727 	sshbuf_free(buf);
1728 	sshbuf_free(arg);
1729 	return ret;
1730 }
1731 
1732 /* Returns 0 if pid exited cleanly, non-zero otherwise */
1733 int
1734 exited_cleanly(pid_t pid, const char *tag, const char *cmd, int quiet)
1735 {
1736 	int status;
1737 
1738 	while (waitpid(pid, &status, 0) == -1) {
1739 		if (errno != EINTR) {
1740 			error("%s: waitpid: %s", tag, strerror(errno));
1741 			return -1;
1742 		}
1743 	}
1744 	if (WIFSIGNALED(status)) {
1745 		error("%s %s exited on signal %d", tag, cmd, WTERMSIG(status));
1746 		return -1;
1747 	} else if (WEXITSTATUS(status) != 0) {
1748 		do_log2(quiet ? SYSLOG_LEVEL_DEBUG1 : SYSLOG_LEVEL_INFO,
1749 		    "%s %s failed, status %d", tag, cmd, WEXITSTATUS(status));
1750 		return -1;
1751 	}
1752 	return 0;
1753 }
1754 
1755 /*
1756  * Check a given path for security. This is defined as all components
1757  * of the path to the file must be owned by either the owner of
1758  * of the file or root and no directories must be group or world writable.
1759  *
1760  * XXX Should any specific check be done for sym links ?
1761  *
1762  * Takes a file name, its stat information (preferably from fstat() to
1763  * avoid races), the uid of the expected owner, their home directory and an
1764  * error buffer plus max size as arguments.
1765  *
1766  * Returns 0 on success and -1 on failure
1767  */
1768 int
1769 safe_path(const char *name, struct stat *stp, const char *pw_dir,
1770     uid_t uid, char *err, size_t errlen)
1771 {
1772 	char buf[PATH_MAX], homedir[PATH_MAX];
1773 	char *cp;
1774 	int comparehome = 0;
1775 	struct stat st;
1776 
1777 	if (realpath(name, buf) == NULL) {
1778 		snprintf(err, errlen, "realpath %s failed: %s", name,
1779 		    strerror(errno));
1780 		return -1;
1781 	}
1782 	if (pw_dir != NULL && realpath(pw_dir, homedir) != NULL)
1783 		comparehome = 1;
1784 
1785 	if (!S_ISREG(stp->st_mode)) {
1786 		snprintf(err, errlen, "%s is not a regular file", buf);
1787 		return -1;
1788 	}
1789 	if ((!platform_sys_dir_uid(stp->st_uid) && stp->st_uid != uid) ||
1790 	    (stp->st_mode & 022) != 0) {
1791 		snprintf(err, errlen, "bad ownership or modes for file %s",
1792 		    buf);
1793 		return -1;
1794 	}
1795 
1796 	/* for each component of the canonical path, walking upwards */
1797 	for (;;) {
1798 		if ((cp = dirname(buf)) == NULL) {
1799 			snprintf(err, errlen, "dirname() failed");
1800 			return -1;
1801 		}
1802 		strlcpy(buf, cp, sizeof(buf));
1803 
1804 		if (stat(buf, &st) < 0 ||
1805 		    (!platform_sys_dir_uid(st.st_uid) && st.st_uid != uid) ||
1806 		    (st.st_mode & 022) != 0) {
1807 			snprintf(err, errlen,
1808 			    "bad ownership or modes for directory %s", buf);
1809 			return -1;
1810 		}
1811 
1812 		/* If are past the homedir then we can stop */
1813 		if (comparehome && strcmp(homedir, buf) == 0)
1814 			break;
1815 
1816 		/*
1817 		 * dirname should always complete with a "/" path,
1818 		 * but we can be paranoid and check for "." too
1819 		 */
1820 		if ((strcmp("/", buf) == 0) || (strcmp(".", buf) == 0))
1821 			break;
1822 	}
1823 	return 0;
1824 }
1825 
1826 /*
1827  * Version of safe_path() that accepts an open file descriptor to
1828  * avoid races.
1829  *
1830  * Returns 0 on success and -1 on failure
1831  */
1832 int
1833 safe_path_fd(int fd, const char *file, struct passwd *pw,
1834     char *err, size_t errlen)
1835 {
1836 	struct stat st;
1837 
1838 	/* check the open file to avoid races */
1839 	if (fstat(fd, &st) < 0) {
1840 		snprintf(err, errlen, "cannot stat file %s: %s",
1841 		    file, strerror(errno));
1842 		return -1;
1843 	}
1844 	return safe_path(file, &st, pw->pw_dir, pw->pw_uid, err, errlen);
1845 }
1846 
1847 /*
1848  * Sets the value of the given variable in the environment.  If the variable
1849  * already exists, its value is overridden.
1850  */
1851 void
1852 child_set_env(char ***envp, u_int *envsizep, const char *name,
1853 	const char *value)
1854 {
1855 	char **env;
1856 	u_int envsize;
1857 	u_int i, namelen;
1858 
1859 	if (strchr(name, '=') != NULL) {
1860 		error("Invalid environment variable \"%.100s\"", name);
1861 		return;
1862 	}
1863 
1864 	/*
1865 	 * If we're passed an uninitialized list, allocate a single null
1866 	 * entry before continuing.
1867 	 */
1868 	if (*envp == NULL && *envsizep == 0) {
1869 		*envp = xmalloc(sizeof(char *));
1870 		*envp[0] = NULL;
1871 		*envsizep = 1;
1872 	}
1873 
1874 	/*
1875 	 * Find the slot where the value should be stored.  If the variable
1876 	 * already exists, we reuse the slot; otherwise we append a new slot
1877 	 * at the end of the array, expanding if necessary.
1878 	 */
1879 	env = *envp;
1880 	namelen = strlen(name);
1881 	for (i = 0; env[i]; i++)
1882 		if (strncmp(env[i], name, namelen) == 0 && env[i][namelen] == '=')
1883 			break;
1884 	if (env[i]) {
1885 		/* Reuse the slot. */
1886 		free(env[i]);
1887 	} else {
1888 		/* New variable.  Expand if necessary. */
1889 		envsize = *envsizep;
1890 		if (i >= envsize - 1) {
1891 			if (envsize >= 1000)
1892 				fatal("child_set_env: too many env vars");
1893 			envsize += 50;
1894 			env = (*envp) = xreallocarray(env, envsize, sizeof(char *));
1895 			*envsizep = envsize;
1896 		}
1897 		/* Need to set the NULL pointer at end of array beyond the new slot. */
1898 		env[i + 1] = NULL;
1899 	}
1900 
1901 	/* Allocate space and format the variable in the appropriate slot. */
1902 	/* XXX xasprintf */
1903 	env[i] = xmalloc(strlen(name) + 1 + strlen(value) + 1);
1904 	snprintf(env[i], strlen(name) + 1 + strlen(value) + 1, "%s=%s", name, value);
1905 }
1906 
1907 /*
1908  * Check and optionally lowercase a domain name, also removes trailing '.'
1909  * Returns 1 on success and 0 on failure, storing an error message in errstr.
1910  */
1911 int
1912 valid_domain(char *name, int makelower, const char **errstr)
1913 {
1914 	size_t i, l = strlen(name);
1915 	u_char c, last = '\0';
1916 	static char errbuf[256];
1917 
1918 	if (l == 0) {
1919 		strlcpy(errbuf, "empty domain name", sizeof(errbuf));
1920 		goto bad;
1921 	}
1922 	if (!isalpha((u_char)name[0]) && !isdigit((u_char)name[0])) {
1923 		snprintf(errbuf, sizeof(errbuf), "domain name \"%.100s\" "
1924 		    "starts with invalid character", name);
1925 		goto bad;
1926 	}
1927 	for (i = 0; i < l; i++) {
1928 		c = tolower((u_char)name[i]);
1929 		if (makelower)
1930 			name[i] = (char)c;
1931 		if (last == '.' && c == '.') {
1932 			snprintf(errbuf, sizeof(errbuf), "domain name "
1933 			    "\"%.100s\" contains consecutive separators", name);
1934 			goto bad;
1935 		}
1936 		if (c != '.' && c != '-' && !isalnum(c) &&
1937 		    c != '_') /* technically invalid, but common */ {
1938 			snprintf(errbuf, sizeof(errbuf), "domain name "
1939 			    "\"%.100s\" contains invalid characters", name);
1940 			goto bad;
1941 		}
1942 		last = c;
1943 	}
1944 	if (name[l - 1] == '.')
1945 		name[l - 1] = '\0';
1946 	if (errstr != NULL)
1947 		*errstr = NULL;
1948 	return 1;
1949 bad:
1950 	if (errstr != NULL)
1951 		*errstr = errbuf;
1952 	return 0;
1953 }
1954 
1955 /*
1956  * Verify that a environment variable name (not including initial '$') is
1957  * valid; consisting of one or more alphanumeric or underscore characters only.
1958  * Returns 1 on valid, 0 otherwise.
1959  */
1960 int
1961 valid_env_name(const char *name)
1962 {
1963 	const char *cp;
1964 
1965 	if (name[0] == '\0')
1966 		return 0;
1967 	for (cp = name; *cp != '\0'; cp++) {
1968 		if (!isalnum((u_char)*cp) && *cp != '_')
1969 			return 0;
1970 	}
1971 	return 1;
1972 }
1973 
1974 const char *
1975 atoi_err(const char *nptr, int *val)
1976 {
1977 	const char *errstr = NULL;
1978 	long long num;
1979 
1980 	if (nptr == NULL || *nptr == '\0')
1981 		return "missing";
1982 	num = strtonum(nptr, 0, INT_MAX, &errstr);
1983 	if (errstr == NULL)
1984 		*val = (int)num;
1985 	return errstr;
1986 }
1987 
1988 int
1989 parse_absolute_time(const char *s, uint64_t *tp)
1990 {
1991 	struct tm tm;
1992 	time_t tt;
1993 	char buf[32], *fmt;
1994 
1995 	*tp = 0;
1996 
1997 	/*
1998 	 * POSIX strptime says "The application shall ensure that there
1999 	 * is white-space or other non-alphanumeric characters between
2000 	 * any two conversion specifications" so arrange things this way.
2001 	 */
2002 	switch (strlen(s)) {
2003 	case 8: /* YYYYMMDD */
2004 		fmt = "%Y-%m-%d";
2005 		snprintf(buf, sizeof(buf), "%.4s-%.2s-%.2s", s, s + 4, s + 6);
2006 		break;
2007 	case 12: /* YYYYMMDDHHMM */
2008 		fmt = "%Y-%m-%dT%H:%M";
2009 		snprintf(buf, sizeof(buf), "%.4s-%.2s-%.2sT%.2s:%.2s",
2010 		    s, s + 4, s + 6, s + 8, s + 10);
2011 		break;
2012 	case 14: /* YYYYMMDDHHMMSS */
2013 		fmt = "%Y-%m-%dT%H:%M:%S";
2014 		snprintf(buf, sizeof(buf), "%.4s-%.2s-%.2sT%.2s:%.2s:%.2s",
2015 		    s, s + 4, s + 6, s + 8, s + 10, s + 12);
2016 		break;
2017 	default:
2018 		return SSH_ERR_INVALID_FORMAT;
2019 	}
2020 
2021 	memset(&tm, 0, sizeof(tm));
2022 	if (strptime(buf, fmt, &tm) == NULL)
2023 		return SSH_ERR_INVALID_FORMAT;
2024 	if ((tt = mktime(&tm)) < 0)
2025 		return SSH_ERR_INVALID_FORMAT;
2026 	/* success */
2027 	*tp = (uint64_t)tt;
2028 	return 0;
2029 }
2030 
2031 void
2032 format_absolute_time(uint64_t t, char *buf, size_t len)
2033 {
2034 	time_t tt = t > INT_MAX ? INT_MAX : t; /* XXX revisit in 2038 :P */
2035 	struct tm tm;
2036 
2037 	localtime_r(&tt, &tm);
2038 	strftime(buf, len, "%Y-%m-%dT%H:%M:%S", &tm);
2039 }
2040 
2041 /* check if path is absolute */
2042 int
2043 path_absolute(const char *path)
2044 {
2045 	return (*path == '/') ? 1 : 0;
2046 }
2047