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1 /* $OpenBSD: misc.c,v 1.109 2017/03/14 00:55:37 dtucker 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/time.h>
33 #include <sys/un.h>
34 
35 #include <limits.h>
36 #include <stdarg.h>
37 #include <stdio.h>
38 #include <stdlib.h>
39 #include <string.h>
40 #include <time.h>
41 #include <unistd.h>
42 
43 #include <netinet/in.h>
44 #include <netinet/in_systm.h>
45 #include <netinet/ip.h>
46 #include <netinet/tcp.h>
47 
48 #include <ctype.h>
49 #include <errno.h>
50 #include <fcntl.h>
51 #include <netdb.h>
52 #ifdef HAVE_PATHS_H
53 # include <paths.h>
54 #include <pwd.h>
55 #endif
56 #ifdef SSH_TUN_OPENBSD
57 #include <net/if.h>
58 #endif
59 
60 #include "xmalloc.h"
61 #include "misc.h"
62 #include "log.h"
63 #include "ssh.h"
64 
65 /* remove newline at end of string */
66 char *
chop(char * s)67 chop(char *s)
68 {
69 	char *t = s;
70 	while (*t) {
71 		if (*t == '\n' || *t == '\r') {
72 			*t = '\0';
73 			return s;
74 		}
75 		t++;
76 	}
77 	return s;
78 
79 }
80 
81 /* set/unset filedescriptor to non-blocking */
82 int
set_nonblock(int fd)83 set_nonblock(int fd)
84 {
85 	int val;
86 
87 	val = fcntl(fd, F_GETFL);
88 	if (val < 0) {
89 		error("fcntl(%d, F_GETFL): %s", fd, strerror(errno));
90 		return (-1);
91 	}
92 	if (val & O_NONBLOCK) {
93 		debug3("fd %d is O_NONBLOCK", fd);
94 		return (0);
95 	}
96 	debug2("fd %d setting O_NONBLOCK", fd);
97 	val |= O_NONBLOCK;
98 	if (fcntl(fd, F_SETFL, val) == -1) {
99 		debug("fcntl(%d, F_SETFL, O_NONBLOCK): %s", fd,
100 		    strerror(errno));
101 		return (-1);
102 	}
103 	return (0);
104 }
105 
106 int
unset_nonblock(int fd)107 unset_nonblock(int fd)
108 {
109 	int val;
110 
111 	val = fcntl(fd, F_GETFL);
112 	if (val < 0) {
113 		error("fcntl(%d, F_GETFL): %s", fd, strerror(errno));
114 		return (-1);
115 	}
116 	if (!(val & O_NONBLOCK)) {
117 		debug3("fd %d is not O_NONBLOCK", fd);
118 		return (0);
119 	}
120 	debug("fd %d clearing O_NONBLOCK", fd);
121 	val &= ~O_NONBLOCK;
122 	if (fcntl(fd, F_SETFL, val) == -1) {
123 		debug("fcntl(%d, F_SETFL, ~O_NONBLOCK): %s",
124 		    fd, strerror(errno));
125 		return (-1);
126 	}
127 	return (0);
128 }
129 
130 const char *
ssh_gai_strerror(int gaierr)131 ssh_gai_strerror(int gaierr)
132 {
133 	if (gaierr == EAI_SYSTEM && errno != 0)
134 		return strerror(errno);
135 	return gai_strerror(gaierr);
136 }
137 
138 /* disable nagle on socket */
139 void
set_nodelay(int fd)140 set_nodelay(int fd)
141 {
142 	int opt;
143 	socklen_t optlen;
144 
145 	optlen = sizeof opt;
146 	if (getsockopt(fd, IPPROTO_TCP, TCP_NODELAY, &opt, &optlen) == -1) {
147 		debug("getsockopt TCP_NODELAY: %.100s", strerror(errno));
148 		return;
149 	}
150 	if (opt == 1) {
151 		debug2("fd %d is TCP_NODELAY", fd);
152 		return;
153 	}
154 	opt = 1;
155 	debug2("fd %d setting TCP_NODELAY", fd);
156 	if (setsockopt(fd, IPPROTO_TCP, TCP_NODELAY, &opt, sizeof opt) == -1)
157 		error("setsockopt TCP_NODELAY: %.100s", strerror(errno));
158 }
159 
160 /* Characters considered whitespace in strsep calls. */
161 #define WHITESPACE " \t\r\n"
162 #define QUOTE	"\""
163 
164 /* return next token in configuration line */
165 char *
strdelim(char ** s)166 strdelim(char **s)
167 {
168 	char *old;
169 	int wspace = 0;
170 
171 	if (*s == NULL)
172 		return NULL;
173 
174 	old = *s;
175 
176 	*s = strpbrk(*s, WHITESPACE QUOTE "=");
177 	if (*s == NULL)
178 		return (old);
179 
180 	if (*s[0] == '\"') {
181 		memmove(*s, *s + 1, strlen(*s)); /* move nul too */
182 		/* Find matching quote */
183 		if ((*s = strpbrk(*s, QUOTE)) == NULL) {
184 			return (NULL);		/* no matching quote */
185 		} else {
186 			*s[0] = '\0';
187 			*s += strspn(*s + 1, WHITESPACE) + 1;
188 			return (old);
189 		}
190 	}
191 
192 	/* Allow only one '=' to be skipped */
193 	if (*s[0] == '=')
194 		wspace = 1;
195 	*s[0] = '\0';
196 
197 	/* Skip any extra whitespace after first token */
198 	*s += strspn(*s + 1, WHITESPACE) + 1;
199 	if (*s[0] == '=' && !wspace)
200 		*s += strspn(*s + 1, WHITESPACE) + 1;
201 
202 	return (old);
203 }
204 
205 struct passwd *
pwcopy(struct passwd * pw)206 pwcopy(struct passwd *pw)
207 {
208 	struct passwd *copy = xcalloc(1, sizeof(*copy));
209 
210 	copy->pw_name = xstrdup(pw->pw_name);
211 	copy->pw_passwd = xstrdup(pw->pw_passwd);
212 #ifdef HAVE_STRUCT_PASSWD_PW_GECOS
213 	copy->pw_gecos = xstrdup(pw->pw_gecos);
214 #endif
215 	copy->pw_uid = pw->pw_uid;
216 	copy->pw_gid = pw->pw_gid;
217 #ifdef HAVE_STRUCT_PASSWD_PW_EXPIRE
218 	copy->pw_expire = pw->pw_expire;
219 #endif
220 #ifdef HAVE_STRUCT_PASSWD_PW_CHANGE
221 	copy->pw_change = pw->pw_change;
222 #endif
223 #ifdef HAVE_STRUCT_PASSWD_PW_CLASS
224 	copy->pw_class = xstrdup(pw->pw_class);
225 #endif
226 	copy->pw_dir = xstrdup(pw->pw_dir);
227 	copy->pw_shell = xstrdup(pw->pw_shell);
228 	return copy;
229 }
230 
231 /*
232  * Convert ASCII string to TCP/IP port number.
233  * Port must be >=0 and <=65535.
234  * Return -1 if invalid.
235  */
236 int
a2port(const char * s)237 a2port(const char *s)
238 {
239 	long long port;
240 	const char *errstr;
241 
242 	port = strtonum(s, 0, 65535, &errstr);
243 	if (errstr != NULL)
244 		return -1;
245 	return (int)port;
246 }
247 
248 int
a2tun(const char * s,int * remote)249 a2tun(const char *s, int *remote)
250 {
251 	const char *errstr = NULL;
252 	char *sp, *ep;
253 	int tun;
254 
255 	if (remote != NULL) {
256 		*remote = SSH_TUNID_ANY;
257 		sp = xstrdup(s);
258 		if ((ep = strchr(sp, ':')) == NULL) {
259 			free(sp);
260 			return (a2tun(s, NULL));
261 		}
262 		ep[0] = '\0'; ep++;
263 		*remote = a2tun(ep, NULL);
264 		tun = a2tun(sp, NULL);
265 		free(sp);
266 		return (*remote == SSH_TUNID_ERR ? *remote : tun);
267 	}
268 
269 	if (strcasecmp(s, "any") == 0)
270 		return (SSH_TUNID_ANY);
271 
272 	tun = strtonum(s, 0, SSH_TUNID_MAX, &errstr);
273 	if (errstr != NULL)
274 		return (SSH_TUNID_ERR);
275 
276 	return (tun);
277 }
278 
279 #define SECONDS		1
280 #define MINUTES		(SECONDS * 60)
281 #define HOURS		(MINUTES * 60)
282 #define DAYS		(HOURS * 24)
283 #define WEEKS		(DAYS * 7)
284 
285 /*
286  * Convert a time string into seconds; format is
287  * a sequence of:
288  *      time[qualifier]
289  *
290  * Valid time qualifiers are:
291  *      <none>  seconds
292  *      s|S     seconds
293  *      m|M     minutes
294  *      h|H     hours
295  *      d|D     days
296  *      w|W     weeks
297  *
298  * Examples:
299  *      90m     90 minutes
300  *      1h30m   90 minutes
301  *      2d      2 days
302  *      1w      1 week
303  *
304  * Return -1 if time string is invalid.
305  */
306 long
convtime(const char * s)307 convtime(const char *s)
308 {
309 	long total, secs, multiplier = 1;
310 	const char *p;
311 	char *endp;
312 
313 	errno = 0;
314 	total = 0;
315 	p = s;
316 
317 	if (p == NULL || *p == '\0')
318 		return -1;
319 
320 	while (*p) {
321 		secs = strtol(p, &endp, 10);
322 		if (p == endp ||
323 		    (errno == ERANGE && (secs == LONG_MIN || secs == LONG_MAX)) ||
324 		    secs < 0)
325 			return -1;
326 
327 		switch (*endp++) {
328 		case '\0':
329 			endp--;
330 			break;
331 		case 's':
332 		case 'S':
333 			break;
334 		case 'm':
335 		case 'M':
336 			multiplier = MINUTES;
337 			break;
338 		case 'h':
339 		case 'H':
340 			multiplier = HOURS;
341 			break;
342 		case 'd':
343 		case 'D':
344 			multiplier = DAYS;
345 			break;
346 		case 'w':
347 		case 'W':
348 			multiplier = WEEKS;
349 			break;
350 		default:
351 			return -1;
352 		}
353 		if (secs >= LONG_MAX / multiplier)
354 			return -1;
355 		secs *= multiplier;
356 		if  (total >= LONG_MAX - secs)
357 			return -1;
358 		total += secs;
359 		if (total < 0)
360 			return -1;
361 		p = endp;
362 	}
363 
364 	return total;
365 }
366 
367 /*
368  * Returns a standardized host+port identifier string.
369  * Caller must free returned string.
370  */
371 char *
put_host_port(const char * host,u_short port)372 put_host_port(const char *host, u_short port)
373 {
374 	char *hoststr;
375 
376 	if (port == 0 || port == SSH_DEFAULT_PORT)
377 		return(xstrdup(host));
378 	if (asprintf(&hoststr, "[%s]:%d", host, (int)port) < 0)
379 		fatal("put_host_port: asprintf: %s", strerror(errno));
380 	debug3("put_host_port: %s", hoststr);
381 	return hoststr;
382 }
383 
384 /*
385  * Search for next delimiter between hostnames/addresses and ports.
386  * Argument may be modified (for termination).
387  * Returns *cp if parsing succeeds.
388  * *cp is set to the start of the next delimiter, if one was found.
389  * If this is the last field, *cp is set to NULL.
390  */
391 char *
hpdelim(char ** cp)392 hpdelim(char **cp)
393 {
394 	char *s, *old;
395 
396 	if (cp == NULL || *cp == NULL)
397 		return NULL;
398 
399 	old = s = *cp;
400 	if (*s == '[') {
401 		if ((s = strchr(s, ']')) == NULL)
402 			return NULL;
403 		else
404 			s++;
405 	} else if ((s = strpbrk(s, ":/")) == NULL)
406 		s = *cp + strlen(*cp); /* skip to end (see first case below) */
407 
408 	switch (*s) {
409 	case '\0':
410 		*cp = NULL;	/* no more fields*/
411 		break;
412 
413 	case ':':
414 	case '/':
415 		*s = '\0';	/* terminate */
416 		*cp = s + 1;
417 		break;
418 
419 	default:
420 		return NULL;
421 	}
422 
423 	return old;
424 }
425 
426 char *
cleanhostname(char * host)427 cleanhostname(char *host)
428 {
429 	if (*host == '[' && host[strlen(host) - 1] == ']') {
430 		host[strlen(host) - 1] = '\0';
431 		return (host + 1);
432 	} else
433 		return host;
434 }
435 
436 char *
colon(char * cp)437 colon(char *cp)
438 {
439 	int flag = 0;
440 
441 	if (*cp == ':')		/* Leading colon is part of file name. */
442 		return NULL;
443 	if (*cp == '[')
444 		flag = 1;
445 
446 	for (; *cp; ++cp) {
447 		if (*cp == '@' && *(cp+1) == '[')
448 			flag = 1;
449 		if (*cp == ']' && *(cp+1) == ':' && flag)
450 			return (cp+1);
451 		if (*cp == ':' && !flag)
452 			return (cp);
453 		if (*cp == '/')
454 			return NULL;
455 	}
456 	return NULL;
457 }
458 
459 /*
460  * Parse a [user@]host[:port] string.
461  * Caller must free returned user and host.
462  * Any of the pointer return arguments may be NULL (useful for syntax checking).
463  * If user was not specified then *userp will be set to NULL.
464  * If port was not specified then *portp will be -1.
465  * Returns 0 on success, -1 on failure.
466  */
467 int
parse_user_host_port(const char * s,char ** userp,char ** hostp,int * portp)468 parse_user_host_port(const char *s, char **userp, char **hostp, int *portp)
469 {
470 	char *sdup, *cp, *tmp;
471 	char *user = NULL, *host = NULL;
472 	int port = -1, ret = -1;
473 
474 	if (userp != NULL)
475 		*userp = NULL;
476 	if (hostp != NULL)
477 		*hostp = NULL;
478 	if (portp != NULL)
479 		*portp = -1;
480 
481 	if ((sdup = tmp = strdup(s)) == NULL)
482 		return -1;
483 	/* Extract optional username */
484 	if ((cp = strchr(tmp, '@')) != NULL) {
485 		*cp = '\0';
486 		if (*tmp == '\0')
487 			goto out;
488 		if ((user = strdup(tmp)) == NULL)
489 			goto out;
490 		tmp = cp + 1;
491 	}
492 	/* Extract mandatory hostname */
493 	if ((cp = hpdelim(&tmp)) == NULL || *cp == '\0')
494 		goto out;
495 	host = xstrdup(cleanhostname(cp));
496 	/* Convert and verify optional port */
497 	if (tmp != NULL && *tmp != '\0') {
498 		if ((port = a2port(tmp)) <= 0)
499 			goto out;
500 	}
501 	/* Success */
502 	if (userp != NULL) {
503 		*userp = user;
504 		user = NULL;
505 	}
506 	if (hostp != NULL) {
507 		*hostp = host;
508 		host = NULL;
509 	}
510 	if (portp != NULL)
511 		*portp = port;
512 	ret = 0;
513  out:
514 	free(sdup);
515 	free(user);
516 	free(host);
517 	return ret;
518 }
519 
520 /* function to assist building execv() arguments */
521 void
addargs(arglist * args,char * fmt,...)522 addargs(arglist *args, char *fmt, ...)
523 {
524 	va_list ap;
525 	char *cp;
526 	u_int nalloc;
527 	int r;
528 
529 	va_start(ap, fmt);
530 	r = vasprintf(&cp, fmt, ap);
531 	va_end(ap);
532 	if (r == -1)
533 		fatal("addargs: argument too long");
534 
535 	nalloc = args->nalloc;
536 	if (args->list == NULL) {
537 		nalloc = 32;
538 		args->num = 0;
539 	} else if (args->num+2 >= nalloc)
540 		nalloc *= 2;
541 
542 	args->list = xreallocarray(args->list, nalloc, sizeof(char *));
543 	args->nalloc = nalloc;
544 	args->list[args->num++] = cp;
545 	args->list[args->num] = NULL;
546 }
547 
548 void
replacearg(arglist * args,u_int which,char * fmt,...)549 replacearg(arglist *args, u_int which, char *fmt, ...)
550 {
551 	va_list ap;
552 	char *cp;
553 	int r;
554 
555 	va_start(ap, fmt);
556 	r = vasprintf(&cp, fmt, ap);
557 	va_end(ap);
558 	if (r == -1)
559 		fatal("replacearg: argument too long");
560 
561 	if (which >= args->num)
562 		fatal("replacearg: tried to replace invalid arg %d >= %d",
563 		    which, args->num);
564 	free(args->list[which]);
565 	args->list[which] = cp;
566 }
567 
568 void
freeargs(arglist * args)569 freeargs(arglist *args)
570 {
571 	u_int i;
572 
573 	if (args->list != NULL) {
574 		for (i = 0; i < args->num; i++)
575 			free(args->list[i]);
576 		free(args->list);
577 		args->nalloc = args->num = 0;
578 		args->list = NULL;
579 	}
580 }
581 
582 /*
583  * Expands tildes in the file name.  Returns data allocated by xmalloc.
584  * Warning: this calls getpw*.
585  */
586 char *
tilde_expand_filename(const char * filename,uid_t uid)587 tilde_expand_filename(const char *filename, uid_t uid)
588 {
589 	const char *path, *sep;
590 	char user[128], *ret;
591 	struct passwd *pw;
592 	u_int len, slash;
593 
594 	if (*filename != '~')
595 		return (xstrdup(filename));
596 	filename++;
597 
598 	path = strchr(filename, '/');
599 	if (path != NULL && path > filename) {		/* ~user/path */
600 		slash = path - filename;
601 		if (slash > sizeof(user) - 1)
602 			fatal("tilde_expand_filename: ~username too long");
603 		memcpy(user, filename, slash);
604 		user[slash] = '\0';
605 		if ((pw = getpwnam(user)) == NULL)
606 			fatal("tilde_expand_filename: No such user %s", user);
607 	} else if ((pw = getpwuid(uid)) == NULL)	/* ~/path */
608 		fatal("tilde_expand_filename: No such uid %ld", (long)uid);
609 
610 	/* Make sure directory has a trailing '/' */
611 	len = strlen(pw->pw_dir);
612 	if (len == 0 || pw->pw_dir[len - 1] != '/')
613 		sep = "/";
614 	else
615 		sep = "";
616 
617 	/* Skip leading '/' from specified path */
618 	if (path != NULL)
619 		filename = path + 1;
620 
621 	if (xasprintf(&ret, "%s%s%s", pw->pw_dir, sep, filename) >= PATH_MAX)
622 		fatal("tilde_expand_filename: Path too long");
623 
624 	return (ret);
625 }
626 
627 /*
628  * Expand a string with a set of %[char] escapes. A number of escapes may be
629  * specified as (char *escape_chars, char *replacement) pairs. The list must
630  * be terminated by a NULL escape_char. Returns replaced string in memory
631  * allocated by xmalloc.
632  */
633 char *
percent_expand(const char * string,...)634 percent_expand(const char *string, ...)
635 {
636 #define EXPAND_MAX_KEYS	16
637 	u_int num_keys, i, j;
638 	struct {
639 		const char *key;
640 		const char *repl;
641 	} keys[EXPAND_MAX_KEYS];
642 	char buf[4096];
643 	va_list ap;
644 
645 	/* Gather keys */
646 	va_start(ap, string);
647 	for (num_keys = 0; num_keys < EXPAND_MAX_KEYS; num_keys++) {
648 		keys[num_keys].key = va_arg(ap, char *);
649 		if (keys[num_keys].key == NULL)
650 			break;
651 		keys[num_keys].repl = va_arg(ap, char *);
652 		if (keys[num_keys].repl == NULL)
653 			fatal("%s: NULL replacement", __func__);
654 	}
655 	if (num_keys == EXPAND_MAX_KEYS && va_arg(ap, char *) != NULL)
656 		fatal("%s: too many keys", __func__);
657 	va_end(ap);
658 
659 	/* Expand string */
660 	*buf = '\0';
661 	for (i = 0; *string != '\0'; string++) {
662 		if (*string != '%') {
663  append:
664 			buf[i++] = *string;
665 			if (i >= sizeof(buf))
666 				fatal("%s: string too long", __func__);
667 			buf[i] = '\0';
668 			continue;
669 		}
670 		string++;
671 		/* %% case */
672 		if (*string == '%')
673 			goto append;
674 		if (*string == '\0')
675 			fatal("%s: invalid format", __func__);
676 		for (j = 0; j < num_keys; j++) {
677 			if (strchr(keys[j].key, *string) != NULL) {
678 				i = strlcat(buf, keys[j].repl, sizeof(buf));
679 				if (i >= sizeof(buf))
680 					fatal("%s: string too long", __func__);
681 				break;
682 			}
683 		}
684 		if (j >= num_keys)
685 			fatal("%s: unknown key %%%c", __func__, *string);
686 	}
687 	return (xstrdup(buf));
688 #undef EXPAND_MAX_KEYS
689 }
690 
691 /*
692  * Read an entire line from a public key file into a static buffer, discarding
693  * lines that exceed the buffer size.  Returns 0 on success, -1 on failure.
694  */
695 int
read_keyfile_line(FILE * f,const char * filename,char * buf,size_t bufsz,u_long * lineno)696 read_keyfile_line(FILE *f, const char *filename, char *buf, size_t bufsz,
697    u_long *lineno)
698 {
699 	while (fgets(buf, bufsz, f) != NULL) {
700 		if (buf[0] == '\0')
701 			continue;
702 		(*lineno)++;
703 		if (buf[strlen(buf) - 1] == '\n' || feof(f)) {
704 			return 0;
705 		} else {
706 			debug("%s: %s line %lu exceeds size limit", __func__,
707 			    filename, *lineno);
708 			/* discard remainder of line */
709 			while (fgetc(f) != '\n' && !feof(f))
710 				;	/* nothing */
711 		}
712 	}
713 	return -1;
714 }
715 
716 int
tun_open(int tun,int mode)717 tun_open(int tun, int mode)
718 {
719 #if defined(CUSTOM_SYS_TUN_OPEN)
720 	return (sys_tun_open(tun, mode));
721 #elif defined(SSH_TUN_OPENBSD)
722 	struct ifreq ifr;
723 	char name[100];
724 	int fd = -1, sock;
725 	const char *tunbase = "tun";
726 
727 	if (mode == SSH_TUNMODE_ETHERNET)
728 		tunbase = "tap";
729 
730 	/* Open the tunnel device */
731 	if (tun <= SSH_TUNID_MAX) {
732 		snprintf(name, sizeof(name), "/dev/%s%d", tunbase, tun);
733 		fd = open(name, O_RDWR);
734 	} else if (tun == SSH_TUNID_ANY) {
735 		for (tun = 100; tun >= 0; tun--) {
736 			snprintf(name, sizeof(name), "/dev/%s%d",
737 			    tunbase, tun);
738 			if ((fd = open(name, O_RDWR)) >= 0)
739 				break;
740 		}
741 	} else {
742 		debug("%s: invalid tunnel %u", __func__, tun);
743 		return -1;
744 	}
745 
746 	if (fd < 0) {
747 		debug("%s: %s open: %s", __func__, name, strerror(errno));
748 		return -1;
749 	}
750 
751 	debug("%s: %s mode %d fd %d", __func__, name, mode, fd);
752 
753 	/* Bring interface up if it is not already */
754 	snprintf(ifr.ifr_name, sizeof(ifr.ifr_name), "%s%d", tunbase, tun);
755 	if ((sock = socket(PF_UNIX, SOCK_STREAM, 0)) == -1)
756 		goto failed;
757 
758 	if (ioctl(sock, SIOCGIFFLAGS, &ifr) == -1) {
759 		debug("%s: get interface %s flags: %s", __func__,
760 		    ifr.ifr_name, strerror(errno));
761 		goto failed;
762 	}
763 
764 	if (!(ifr.ifr_flags & IFF_UP)) {
765 		ifr.ifr_flags |= IFF_UP;
766 		if (ioctl(sock, SIOCSIFFLAGS, &ifr) == -1) {
767 			debug("%s: activate interface %s: %s", __func__,
768 			    ifr.ifr_name, strerror(errno));
769 			goto failed;
770 		}
771 	}
772 
773 	close(sock);
774 	return fd;
775 
776  failed:
777 	if (fd >= 0)
778 		close(fd);
779 	if (sock >= 0)
780 		close(sock);
781 	return -1;
782 #else
783 	error("Tunnel interfaces are not supported on this platform");
784 	return (-1);
785 #endif
786 }
787 
788 void
sanitise_stdfd(void)789 sanitise_stdfd(void)
790 {
791 	int nullfd, dupfd;
792 
793 	if ((nullfd = dupfd = open(_PATH_DEVNULL, O_RDWR)) == -1) {
794 		fprintf(stderr, "Couldn't open /dev/null: %s\n",
795 		    strerror(errno));
796 		exit(1);
797 	}
798 	while (++dupfd <= STDERR_FILENO) {
799 		/* Only populate closed fds. */
800 		if (fcntl(dupfd, F_GETFL) == -1 && errno == EBADF) {
801 			if (dup2(nullfd, dupfd) == -1) {
802 				fprintf(stderr, "dup2: %s\n", strerror(errno));
803 				exit(1);
804 			}
805 		}
806 	}
807 	if (nullfd > STDERR_FILENO)
808 		close(nullfd);
809 }
810 
811 char *
tohex(const void * vp,size_t l)812 tohex(const void *vp, size_t l)
813 {
814 	const u_char *p = (const u_char *)vp;
815 	char b[3], *r;
816 	size_t i, hl;
817 
818 	if (l > 65536)
819 		return xstrdup("tohex: length > 65536");
820 
821 	hl = l * 2 + 1;
822 	r = xcalloc(1, hl);
823 	for (i = 0; i < l; i++) {
824 		snprintf(b, sizeof(b), "%02x", p[i]);
825 		strlcat(r, b, hl);
826 	}
827 	return (r);
828 }
829 
830 u_int64_t
get_u64(const void * vp)831 get_u64(const void *vp)
832 {
833 	const u_char *p = (const u_char *)vp;
834 	u_int64_t v;
835 
836 	v  = (u_int64_t)p[0] << 56;
837 	v |= (u_int64_t)p[1] << 48;
838 	v |= (u_int64_t)p[2] << 40;
839 	v |= (u_int64_t)p[3] << 32;
840 	v |= (u_int64_t)p[4] << 24;
841 	v |= (u_int64_t)p[5] << 16;
842 	v |= (u_int64_t)p[6] << 8;
843 	v |= (u_int64_t)p[7];
844 
845 	return (v);
846 }
847 
848 u_int32_t
get_u32(const void * vp)849 get_u32(const void *vp)
850 {
851 	const u_char *p = (const u_char *)vp;
852 	u_int32_t v;
853 
854 	v  = (u_int32_t)p[0] << 24;
855 	v |= (u_int32_t)p[1] << 16;
856 	v |= (u_int32_t)p[2] << 8;
857 	v |= (u_int32_t)p[3];
858 
859 	return (v);
860 }
861 
862 u_int32_t
get_u32_le(const void * vp)863 get_u32_le(const void *vp)
864 {
865 	const u_char *p = (const u_char *)vp;
866 	u_int32_t v;
867 
868 	v  = (u_int32_t)p[0];
869 	v |= (u_int32_t)p[1] << 8;
870 	v |= (u_int32_t)p[2] << 16;
871 	v |= (u_int32_t)p[3] << 24;
872 
873 	return (v);
874 }
875 
876 u_int16_t
get_u16(const void * vp)877 get_u16(const void *vp)
878 {
879 	const u_char *p = (const u_char *)vp;
880 	u_int16_t v;
881 
882 	v  = (u_int16_t)p[0] << 8;
883 	v |= (u_int16_t)p[1];
884 
885 	return (v);
886 }
887 
888 void
put_u64(void * vp,u_int64_t v)889 put_u64(void *vp, u_int64_t v)
890 {
891 	u_char *p = (u_char *)vp;
892 
893 	p[0] = (u_char)(v >> 56) & 0xff;
894 	p[1] = (u_char)(v >> 48) & 0xff;
895 	p[2] = (u_char)(v >> 40) & 0xff;
896 	p[3] = (u_char)(v >> 32) & 0xff;
897 	p[4] = (u_char)(v >> 24) & 0xff;
898 	p[5] = (u_char)(v >> 16) & 0xff;
899 	p[6] = (u_char)(v >> 8) & 0xff;
900 	p[7] = (u_char)v & 0xff;
901 }
902 
903 void
put_u32(void * vp,u_int32_t v)904 put_u32(void *vp, u_int32_t v)
905 {
906 	u_char *p = (u_char *)vp;
907 
908 	p[0] = (u_char)(v >> 24) & 0xff;
909 	p[1] = (u_char)(v >> 16) & 0xff;
910 	p[2] = (u_char)(v >> 8) & 0xff;
911 	p[3] = (u_char)v & 0xff;
912 }
913 
914 void
put_u32_le(void * vp,u_int32_t v)915 put_u32_le(void *vp, u_int32_t v)
916 {
917 	u_char *p = (u_char *)vp;
918 
919 	p[0] = (u_char)v & 0xff;
920 	p[1] = (u_char)(v >> 8) & 0xff;
921 	p[2] = (u_char)(v >> 16) & 0xff;
922 	p[3] = (u_char)(v >> 24) & 0xff;
923 }
924 
925 void
put_u16(void * vp,u_int16_t v)926 put_u16(void *vp, u_int16_t v)
927 {
928 	u_char *p = (u_char *)vp;
929 
930 	p[0] = (u_char)(v >> 8) & 0xff;
931 	p[1] = (u_char)v & 0xff;
932 }
933 
934 void
ms_subtract_diff(struct timeval * start,int * ms)935 ms_subtract_diff(struct timeval *start, int *ms)
936 {
937 	struct timeval diff, finish;
938 
939 	gettimeofday(&finish, NULL);
940 	timersub(&finish, start, &diff);
941 	*ms -= (diff.tv_sec * 1000) + (diff.tv_usec / 1000);
942 }
943 
944 void
ms_to_timeval(struct timeval * tv,int ms)945 ms_to_timeval(struct timeval *tv, int ms)
946 {
947 	if (ms < 0)
948 		ms = 0;
949 	tv->tv_sec = ms / 1000;
950 	tv->tv_usec = (ms % 1000) * 1000;
951 }
952 
953 time_t
monotime(void)954 monotime(void)
955 {
956 #if defined(HAVE_CLOCK_GETTIME) && \
957     (defined(CLOCK_MONOTONIC) || defined(CLOCK_BOOTTIME))
958 	struct timespec ts;
959 	static int gettime_failed = 0;
960 
961 	if (!gettime_failed) {
962 #if defined(CLOCK_BOOTTIME)
963 		if (clock_gettime(CLOCK_BOOTTIME, &ts) == 0)
964 			return (ts.tv_sec);
965 #endif
966 #if defined(CLOCK_MONOTONIC)
967 		if (clock_gettime(CLOCK_MONOTONIC, &ts) == 0)
968 			return (ts.tv_sec);
969 #endif
970 		debug3("clock_gettime: %s", strerror(errno));
971 		gettime_failed = 1;
972 	}
973 #endif /* HAVE_CLOCK_GETTIME && (CLOCK_MONOTONIC || CLOCK_BOOTTIME */
974 
975 	return time(NULL);
976 }
977 
978 double
monotime_double(void)979 monotime_double(void)
980 {
981 #if defined(HAVE_CLOCK_GETTIME) && \
982     (defined(CLOCK_MONOTONIC) || defined(CLOCK_BOOTTIME))
983 	struct timespec ts;
984 	static int gettime_failed = 0;
985 
986 	if (!gettime_failed) {
987 #if defined(CLOCK_BOOTTIME)
988 		if (clock_gettime(CLOCK_BOOTTIME, &ts) == 0)
989 			return (ts.tv_sec + (double)ts.tv_nsec / 1000000000);
990 #endif
991 #if defined(CLOCK_MONOTONIC)
992 		if (clock_gettime(CLOCK_MONOTONIC, &ts) == 0)
993 			return (ts.tv_sec + (double)ts.tv_nsec / 1000000000);
994 #endif
995 		debug3("clock_gettime: %s", strerror(errno));
996 		gettime_failed = 1;
997 	}
998 #endif /* HAVE_CLOCK_GETTIME && (CLOCK_MONOTONIC || CLOCK_BOOTTIME */
999 
1000 	return (double)time(NULL);
1001 }
1002 
1003 void
bandwidth_limit_init(struct bwlimit * bw,u_int64_t kbps,size_t buflen)1004 bandwidth_limit_init(struct bwlimit *bw, u_int64_t kbps, size_t buflen)
1005 {
1006 	bw->buflen = buflen;
1007 	bw->rate = kbps;
1008 	bw->thresh = bw->rate;
1009 	bw->lamt = 0;
1010 	timerclear(&bw->bwstart);
1011 	timerclear(&bw->bwend);
1012 }
1013 
1014 /* Callback from read/write loop to insert bandwidth-limiting delays */
1015 void
bandwidth_limit(struct bwlimit * bw,size_t read_len)1016 bandwidth_limit(struct bwlimit *bw, size_t read_len)
1017 {
1018 	u_int64_t waitlen;
1019 	struct timespec ts, rm;
1020 
1021 	if (!timerisset(&bw->bwstart)) {
1022 		gettimeofday(&bw->bwstart, NULL);
1023 		return;
1024 	}
1025 
1026 	bw->lamt += read_len;
1027 	if (bw->lamt < bw->thresh)
1028 		return;
1029 
1030 	gettimeofday(&bw->bwend, NULL);
1031 	timersub(&bw->bwend, &bw->bwstart, &bw->bwend);
1032 	if (!timerisset(&bw->bwend))
1033 		return;
1034 
1035 	bw->lamt *= 8;
1036 	waitlen = (double)1000000L * bw->lamt / bw->rate;
1037 
1038 	bw->bwstart.tv_sec = waitlen / 1000000L;
1039 	bw->bwstart.tv_usec = waitlen % 1000000L;
1040 
1041 	if (timercmp(&bw->bwstart, &bw->bwend, >)) {
1042 		timersub(&bw->bwstart, &bw->bwend, &bw->bwend);
1043 
1044 		/* Adjust the wait time */
1045 		if (bw->bwend.tv_sec) {
1046 			bw->thresh /= 2;
1047 			if (bw->thresh < bw->buflen / 4)
1048 				bw->thresh = bw->buflen / 4;
1049 		} else if (bw->bwend.tv_usec < 10000) {
1050 			bw->thresh *= 2;
1051 			if (bw->thresh > bw->buflen * 8)
1052 				bw->thresh = bw->buflen * 8;
1053 		}
1054 
1055 		TIMEVAL_TO_TIMESPEC(&bw->bwend, &ts);
1056 		while (nanosleep(&ts, &rm) == -1) {
1057 			if (errno != EINTR)
1058 				break;
1059 			ts = rm;
1060 		}
1061 	}
1062 
1063 	bw->lamt = 0;
1064 	gettimeofday(&bw->bwstart, NULL);
1065 }
1066 
1067 /* Make a template filename for mk[sd]temp() */
1068 void
mktemp_proto(char * s,size_t len)1069 mktemp_proto(char *s, size_t len)
1070 {
1071 	const char *tmpdir;
1072 	int r;
1073 
1074 	if ((tmpdir = getenv("TMPDIR")) != NULL) {
1075 		r = snprintf(s, len, "%s/ssh-XXXXXXXXXXXX", tmpdir);
1076 		if (r > 0 && (size_t)r < len)
1077 			return;
1078 	}
1079 	r = snprintf(s, len, "/tmp/ssh-XXXXXXXXXXXX");
1080 	if (r < 0 || (size_t)r >= len)
1081 		fatal("%s: template string too short", __func__);
1082 }
1083 
1084 static const struct {
1085 	const char *name;
1086 	int value;
1087 } ipqos[] = {
1088 	{ "af11", IPTOS_DSCP_AF11 },
1089 	{ "af12", IPTOS_DSCP_AF12 },
1090 	{ "af13", IPTOS_DSCP_AF13 },
1091 	{ "af21", IPTOS_DSCP_AF21 },
1092 	{ "af22", IPTOS_DSCP_AF22 },
1093 	{ "af23", IPTOS_DSCP_AF23 },
1094 	{ "af31", IPTOS_DSCP_AF31 },
1095 	{ "af32", IPTOS_DSCP_AF32 },
1096 	{ "af33", IPTOS_DSCP_AF33 },
1097 	{ "af41", IPTOS_DSCP_AF41 },
1098 	{ "af42", IPTOS_DSCP_AF42 },
1099 	{ "af43", IPTOS_DSCP_AF43 },
1100 	{ "cs0", IPTOS_DSCP_CS0 },
1101 	{ "cs1", IPTOS_DSCP_CS1 },
1102 	{ "cs2", IPTOS_DSCP_CS2 },
1103 	{ "cs3", IPTOS_DSCP_CS3 },
1104 	{ "cs4", IPTOS_DSCP_CS4 },
1105 	{ "cs5", IPTOS_DSCP_CS5 },
1106 	{ "cs6", IPTOS_DSCP_CS6 },
1107 	{ "cs7", IPTOS_DSCP_CS7 },
1108 	{ "ef", IPTOS_DSCP_EF },
1109 	{ "lowdelay", IPTOS_LOWDELAY },
1110 	{ "throughput", IPTOS_THROUGHPUT },
1111 	{ "reliability", IPTOS_RELIABILITY },
1112 	{ NULL, -1 }
1113 };
1114 
1115 int
parse_ipqos(const char * cp)1116 parse_ipqos(const char *cp)
1117 {
1118 	u_int i;
1119 	char *ep;
1120 	long val;
1121 
1122 	if (cp == NULL)
1123 		return -1;
1124 	for (i = 0; ipqos[i].name != NULL; i++) {
1125 		if (strcasecmp(cp, ipqos[i].name) == 0)
1126 			return ipqos[i].value;
1127 	}
1128 	/* Try parsing as an integer */
1129 	val = strtol(cp, &ep, 0);
1130 	if (*cp == '\0' || *ep != '\0' || val < 0 || val > 255)
1131 		return -1;
1132 	return val;
1133 }
1134 
1135 const char *
iptos2str(int iptos)1136 iptos2str(int iptos)
1137 {
1138 	int i;
1139 	static char iptos_str[sizeof "0xff"];
1140 
1141 	for (i = 0; ipqos[i].name != NULL; i++) {
1142 		if (ipqos[i].value == iptos)
1143 			return ipqos[i].name;
1144 	}
1145 	snprintf(iptos_str, sizeof iptos_str, "0x%02x", iptos);
1146 	return iptos_str;
1147 }
1148 
1149 void
lowercase(char * s)1150 lowercase(char *s)
1151 {
1152 	for (; *s; s++)
1153 		*s = tolower((u_char)*s);
1154 }
1155 
1156 int
unix_listener(const char * path,int backlog,int unlink_first)1157 unix_listener(const char *path, int backlog, int unlink_first)
1158 {
1159 	struct sockaddr_un sunaddr;
1160 	int saved_errno, sock;
1161 
1162 	memset(&sunaddr, 0, sizeof(sunaddr));
1163 	sunaddr.sun_family = AF_UNIX;
1164 	if (strlcpy(sunaddr.sun_path, path, sizeof(sunaddr.sun_path)) >= sizeof(sunaddr.sun_path)) {
1165 		error("%s: \"%s\" too long for Unix domain socket", __func__,
1166 		    path);
1167 		errno = ENAMETOOLONG;
1168 		return -1;
1169 	}
1170 
1171 	sock = socket(PF_UNIX, SOCK_STREAM, 0);
1172 	if (sock < 0) {
1173 		saved_errno = errno;
1174 		error("socket: %.100s", strerror(errno));
1175 		errno = saved_errno;
1176 		return -1;
1177 	}
1178 	if (unlink_first == 1) {
1179 		if (unlink(path) != 0 && errno != ENOENT)
1180 			error("unlink(%s): %.100s", path, strerror(errno));
1181 	}
1182 	if (bind(sock, (struct sockaddr *)&sunaddr, sizeof(sunaddr)) < 0) {
1183 		saved_errno = errno;
1184 		error("bind: %.100s", strerror(errno));
1185 		close(sock);
1186 		error("%s: cannot bind to path: %s", __func__, path);
1187 		errno = saved_errno;
1188 		return -1;
1189 	}
1190 	if (listen(sock, backlog) < 0) {
1191 		saved_errno = errno;
1192 		error("listen: %.100s", strerror(errno));
1193 		close(sock);
1194 		unlink(path);
1195 		error("%s: cannot listen on path: %s", __func__, path);
1196 		errno = saved_errno;
1197 		return -1;
1198 	}
1199 	return sock;
1200 }
1201 
1202 void
sock_set_v6only(int s)1203 sock_set_v6only(int s)
1204 {
1205 #if defined(IPV6_V6ONLY) && !defined(__OpenBSD__)
1206 	int on = 1;
1207 
1208 	debug3("%s: set socket %d IPV6_V6ONLY", __func__, s);
1209 	if (setsockopt(s, IPPROTO_IPV6, IPV6_V6ONLY, &on, sizeof(on)) == -1)
1210 		error("setsockopt IPV6_V6ONLY: %s", strerror(errno));
1211 #endif
1212 }
1213 
1214 /*
1215  * Compares two strings that maybe be NULL. Returns non-zero if strings
1216  * are both NULL or are identical, returns zero otherwise.
1217  */
1218 static int
strcmp_maybe_null(const char * a,const char * b)1219 strcmp_maybe_null(const char *a, const char *b)
1220 {
1221 	if ((a == NULL && b != NULL) || (a != NULL && b == NULL))
1222 		return 0;
1223 	if (a != NULL && strcmp(a, b) != 0)
1224 		return 0;
1225 	return 1;
1226 }
1227 
1228 /*
1229  * Compare two forwards, returning non-zero if they are identical or
1230  * zero otherwise.
1231  */
1232 int
forward_equals(const struct Forward * a,const struct Forward * b)1233 forward_equals(const struct Forward *a, const struct Forward *b)
1234 {
1235 	if (strcmp_maybe_null(a->listen_host, b->listen_host) == 0)
1236 		return 0;
1237 	if (a->listen_port != b->listen_port)
1238 		return 0;
1239 	if (strcmp_maybe_null(a->listen_path, b->listen_path) == 0)
1240 		return 0;
1241 	if (strcmp_maybe_null(a->connect_host, b->connect_host) == 0)
1242 		return 0;
1243 	if (a->connect_port != b->connect_port)
1244 		return 0;
1245 	if (strcmp_maybe_null(a->connect_path, b->connect_path) == 0)
1246 		return 0;
1247 	/* allocated_port and handle are not checked */
1248 	return 1;
1249 }
1250 
1251 /* returns 1 if bind to specified port by specified user is permitted */
1252 int
bind_permitted(int port,uid_t uid)1253 bind_permitted(int port, uid_t uid)
1254 {
1255 	if (port < IPPORT_RESERVED && uid != 0)
1256 		return 0;
1257 	return 1;
1258 }
1259 
1260 /* returns 1 if process is already daemonized, 0 otherwise */
1261 int
daemonized(void)1262 daemonized(void)
1263 {
1264 	int fd;
1265 
1266 	if ((fd = open(_PATH_TTY, O_RDONLY | O_NOCTTY)) >= 0) {
1267 		close(fd);
1268 		return 0;	/* have controlling terminal */
1269 	}
1270 	if (getppid() != 1)
1271 		return 0;	/* parent is not init */
1272 	if (getsid(0) != getpid())
1273 		return 0;	/* not session leader */
1274 	debug3("already daemonized");
1275 	return 1;
1276 }
1277