xref: /dragonfly/usr.sbin/authpf/authpf.c (revision 2c3b1d1b)
1 /*	$OpenBSD: authpf.c,v 1.112 2009/01/10 19:08:53 miod Exp $	*/
2 
3 /*
4  * Copyright (C) 1998 - 2007 Bob Beck (beck@openbsd.org).
5  *
6  * Permission to use, copy, modify, and distribute this software for any
7  * purpose with or without fee is hereby granted, provided that the above
8  * copyright notice and this permission notice appear in all copies.
9  *
10  * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
11  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
12  * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
13  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
14  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
15  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
16  * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
17  *
18  * $FreeBSD: head/contrib/pf/authpf/authpf.c 223637 2011-06-28 11:57:25Z bz $
19  */
20 
21 #include <sys/param.h>
22 #include <sys/types.h>
23 #include <sys/ioctl.h>
24 #include <sys/socket.h>
25 #include <sys/stat.h>
26 #include <sys/time.h>
27 #include <sys/wait.h>
28 
29 #include <net/if.h>
30 #include <net/pf/pfvar.h>
31 #include <arpa/inet.h>
32 
33 #include <err.h>
34 #include <errno.h>
35 #include <fcntl.h>
36 #include <login_cap.h>
37 #include <pwd.h>
38 #include <signal.h>
39 #include <stdio.h>
40 #include <stdlib.h>
41 #include <string.h>
42 #include <syslog.h>
43 #include <unistd.h>
44 
45 #include "pathnames.h"
46 
47 #define __dead __dead2
48 
49 static int	read_config(FILE *);
50 static void	print_message(const char *);
51 static int	allowed_luser(const char *);
52 static int	check_luser(const char *, const char *);
53 static int	remove_stale_rulesets(void);
54 static int	change_filter(int, const char *, const char *);
55 static int	change_table(int, const char *);
56 static void	authpf_kill_states(void);
57 
58 int	dev_fd;			/* pf device */
59 char	anchorname[PF_ANCHOR_NAME_SIZE] = "authpf";
60 char	rulesetname[MAXPATHLEN - PF_ANCHOR_NAME_SIZE - 2];
61 char	tablename[PF_TABLE_NAME_SIZE] = "authpf_users";
62 
63 FILE	*pidfp;
64 char	 luser[MAXLOGNAME];	/* username */
65 char	 ipsrc[256];		/* ip as a string */
66 char	 pidfile[MAXPATHLEN];	/* we save pid in this file. */
67 
68 struct timeval	Tstart, Tend;	/* start and end times of session */
69 
70 volatile sig_atomic_t	want_death;
71 static void		need_death(int signo);
72 static __dead void	do_death(int);
73 
74 /*
75  * User shell for authenticating gateways. Sole purpose is to allow
76  * a user to ssh to a gateway, and have the gateway modify packet
77  * filters to allow access, then remove access when the user finishes
78  * up. Meant to be used only from ssh(1) connections.
79  */
80 int
main(int argc __unused,char ** argv __unused)81 main(int argc __unused, char **argv __unused)
82 {
83 	int		 lockcnt = 0, n, pidfd;
84 	FILE		*config;
85 	struct in6_addr	 ina;
86 	struct passwd	*pw;
87 	char		*cp;
88 	gid_t		 gid;
89 	uid_t		 uid;
90 	const char	*shell;
91 	login_cap_t	*lc;
92 
93 	config = fopen(PATH_CONFFILE, "r");
94 	if (config == NULL) {
95 		syslog(LOG_ERR, "cannot open %s (%m)", PATH_CONFFILE);
96 		exit(1);
97 	}
98 
99 	if ((cp = getenv("SSH_TTY")) == NULL) {
100 		syslog(LOG_ERR, "non-interactive session connection for authpf");
101 		exit(1);
102 	}
103 
104 	if ((cp = getenv("SSH_CLIENT")) == NULL) {
105 		syslog(LOG_ERR, "cannot determine connection source");
106 		exit(1);
107 	}
108 
109 	if (strlcpy(ipsrc, cp, sizeof(ipsrc)) >= sizeof(ipsrc)) {
110 		syslog(LOG_ERR, "SSH_CLIENT variable too long");
111 		exit(1);
112 	}
113 	cp = strchr(ipsrc, ' ');
114 	if (!cp) {
115 		syslog(LOG_ERR, "corrupt SSH_CLIENT variable %s", ipsrc);
116 		exit(1);
117 	}
118 	*cp = '\0';
119 	if (inet_pton(AF_INET, ipsrc, &ina) != 1 &&
120 	    inet_pton(AF_INET6, ipsrc, &ina) != 1) {
121 		syslog(LOG_ERR,
122 		    "cannot determine IP from SSH_CLIENT %s", ipsrc);
123 		exit(1);
124 	}
125 	/* open the pf device */
126 	dev_fd = open(PATH_DEVFILE, O_RDWR);
127 	if (dev_fd == -1) {
128 		syslog(LOG_ERR, "cannot open packet filter device (%m)");
129 		goto die;
130 	}
131 
132 	uid = getuid();
133 	pw = getpwuid(uid);
134 	if (pw == NULL) {
135 		syslog(LOG_ERR, "cannot find user for uid %u", uid);
136 		goto die;
137 	}
138 
139 	if ((lc = login_getclass(pw->pw_class)) != NULL)
140 		shell = login_getcapstr(lc, "shell", pw->pw_shell,
141 		    pw->pw_shell);
142 	else
143 		shell = pw->pw_shell;
144 
145 
146 
147 	if (strcmp(shell, PATH_AUTHPF_SHELL)) {
148 		syslog(LOG_ERR, "wrong shell for user %s, uid %u",
149 		    pw->pw_name, pw->pw_uid);
150 		login_close(lc);
151 		goto die;
152 	}
153 
154 	login_close(lc);
155 
156 	/*
157 	 * Paranoia, but this data _does_ come from outside authpf, and
158 	 * truncation would be bad.
159 	 */
160 	if (strlcpy(luser, pw->pw_name, sizeof(luser)) >= sizeof(luser)) {
161 		syslog(LOG_ERR, "username too long: %s", pw->pw_name);
162 		goto die;
163 	}
164 
165 	if ((n = snprintf(rulesetname, sizeof(rulesetname), "%s(%ld)",
166 	    luser, (long)getpid())) < 0 || (u_int)n >= sizeof(rulesetname)) {
167 		syslog(LOG_INFO, "%s(%ld) too large, ruleset name will be %ld",
168 		    luser, (long)getpid(), (long)getpid());
169 		if ((n = snprintf(rulesetname, sizeof(rulesetname), "%ld",
170 		    (long)getpid())) < 0 || (u_int)n >= sizeof(rulesetname)) {
171 			syslog(LOG_ERR, "pid too large for ruleset name");
172 			goto die;
173 		}
174 	}
175 
176 
177 	/* Make our entry in /var/authpf as /var/authpf/ipaddr */
178 	n = snprintf(pidfile, sizeof(pidfile), "%s/%s", PATH_PIDFILE, ipsrc);
179 	if (n < 0 || (u_int)n >= sizeof(pidfile)) {
180 		syslog(LOG_ERR, "path to pidfile too long");
181 		goto die;
182 	}
183 
184 	/*
185 	 * If someone else is already using this ip, then this person
186 	 * wants to switch users - so kill the old process and exit
187 	 * as well.
188 	 *
189 	 * Note, we could print a message and tell them to log out, but the
190 	 * usual case of this is that someone has left themselves logged in,
191 	 * with the authenticated connection iconized and someone else walks
192 	 * up to use and automatically logs in before using. If this just
193 	 * gets rid of the old one silently, the new user never knows they
194 	 * could have used someone else's old authentication. If we
195 	 * tell them to log out before switching users it is an invitation
196 	 * for abuse.
197 	 */
198 
199 	do {
200 		int	save_errno, otherpid = -1;
201 		char	otherluser[MAXLOGNAME];
202 
203 		if ((pidfd = open(pidfile, O_RDWR|O_CREAT, 0644)) == -1 ||
204 		    (pidfp = fdopen(pidfd, "r+")) == NULL) {
205 			if (pidfd != -1)
206 				close(pidfd);
207 			syslog(LOG_ERR, "cannot open or create %s: %s", pidfile,
208 			    strerror(errno));
209 			goto die;
210 		}
211 
212 		if (flock(fileno(pidfp), LOCK_EX|LOCK_NB) == 0)
213 			break;
214 		save_errno = errno;
215 
216 		/* Mark our pid, and username to our file. */
217 
218 		rewind(pidfp);
219 		/* 31 == MAXLOGNAME - 1 */
220 		if (fscanf(pidfp, "%d\n%31s\n", &otherpid, otherluser) != 2)
221 			otherpid = -1;
222 		syslog(LOG_DEBUG, "tried to lock %s, in use by pid %d: %s",
223 		    pidfile, otherpid, strerror(save_errno));
224 
225 		if (otherpid > 0) {
226 			syslog(LOG_INFO,
227 			    "killing prior auth (pid %d) of %s by user %s",
228 			    otherpid, ipsrc, otherluser);
229 			if (kill((pid_t) otherpid, SIGTERM) == -1) {
230 				syslog(LOG_INFO,
231 				    "could not kill process %d: (%m)",
232 				    otherpid);
233 			}
234 		}
235 
236 		/*
237 		 * We try to kill the previous process and acquire the lock
238 		 * for 10 seconds, trying once a second. if we can't after
239 		 * 10 attempts we log an error and give up.
240 		 */
241 		if (++lockcnt > 10) {
242 			syslog(LOG_ERR, "cannot kill previous authpf (pid %d)",
243 			    otherpid);
244 			fclose(pidfp);
245 			pidfp = NULL;
246 			goto dogdeath;
247 		}
248 		sleep(1);
249 
250 		/* re-open, and try again. The previous authpf process
251 		 * we killed above should unlink the file and release
252 		 * it's lock, giving us a chance to get it now
253 		 */
254 		fclose(pidfp);
255 		pidfp = NULL;
256 	} while (1);
257 
258 	/* whack the group list */
259 	gid = getegid();
260 	if (setgroups(1, &gid) == -1) {
261 		syslog(LOG_INFO, "setgroups: %s", strerror(errno));
262 		do_death(0);
263 	}
264 
265 	/* revoke privs */
266 	uid = getuid();
267 	if (setresuid(uid, uid, uid) == -1) {
268 		syslog(LOG_INFO, "setresuid: %s", strerror(errno));
269 		do_death(0);
270 	}
271 	openlog("authpf", LOG_PID | LOG_NDELAY, LOG_DAEMON);
272 
273 	if (!check_luser(PATH_BAN_DIR, luser) || !allowed_luser(luser)) {
274 		syslog(LOG_INFO, "user %s prohibited", luser);
275 		do_death(0);
276 	}
277 
278 	if (read_config(config)) {
279 		syslog(LOG_ERR, "invalid config file %s", PATH_CONFFILE);
280 		do_death(0);
281 	}
282 
283 	if (remove_stale_rulesets()) {
284 		syslog(LOG_INFO, "error removing stale rulesets");
285 		do_death(0);
286 	}
287 
288 	/* We appear to be making headway, so actually mark our pid */
289 	rewind(pidfp);
290 	fprintf(pidfp, "%ld\n%s\n", (long)getpid(), luser);
291 	fflush(pidfp);
292 	ftruncate(fileno(pidfp), ftell(pidfp));
293 
294 	if (change_filter(1, luser, ipsrc) == -1) {
295 		printf("Unable to modify filters\r\n");
296 		do_death(0);
297 	}
298 	if (change_table(1, ipsrc) == -1) {
299 		printf("Unable to modify table\r\n");
300 		change_filter(0, luser, ipsrc);
301 		do_death(0);
302 	}
303 
304 	signal(SIGTERM, need_death);
305 	signal(SIGINT, need_death);
306 	signal(SIGALRM, need_death);
307 	signal(SIGPIPE, need_death);
308 	signal(SIGHUP, need_death);
309 	signal(SIGQUIT, need_death);
310 	signal(SIGTSTP, need_death);
311 	while (1) {
312 		printf("\r\nHello %s. ", luser);
313 		printf("You are authenticated from host \"%s\"\r\n", ipsrc);
314 		setproctitle("%s@%s", luser, ipsrc);
315 		print_message(PATH_MESSAGE);
316 		while (1) {
317 			sleep(10);
318 			if (want_death)
319 				do_death(1);
320 		}
321 	}
322 
323 	/* NOTREACHED */
324 dogdeath:
325 	printf("\r\n\r\nSorry, this service is currently unavailable due to ");
326 	printf("technical difficulties\r\n\r\n");
327 	print_message(PATH_PROBLEM);
328 	printf("\r\nYour authentication process (pid %ld) was unable to run\n",
329 	    (long)getpid());
330 	sleep(180); /* them lusers read reaaaaal slow */
331 die:
332 	do_death(0);
333 }
334 
335 /*
336  * reads config file in PATH_CONFFILE to set optional behaviours up
337  */
338 static int
read_config(FILE * f)339 read_config(FILE *f)
340 {
341 	char	buf[1024];
342 	int	i = 0;
343 
344 	do {
345 		char	**ap;
346 		char	 *pair[4], *cp, *tp;
347 		int	  len;
348 
349 		if (fgets(buf, sizeof(buf), f) == NULL) {
350 			fclose(f);
351 			return (0);
352 		}
353 		i++;
354 		len = strlen(buf);
355 		if (len == 0)
356 			continue;
357 		if (buf[len - 1] != '\n' && !feof(f)) {
358 			syslog(LOG_ERR, "line %d too long in %s", i,
359 			    PATH_CONFFILE);
360 			return (1);
361 		}
362 		buf[len - 1] = '\0';
363 
364 		for (cp = buf; *cp == ' ' || *cp == '\t'; cp++)
365 			; /* nothing */
366 
367 		if (!*cp || *cp == '#' || *cp == '\n')
368 			continue;
369 
370 		for (ap = pair; ap < &pair[3] &&
371 		    (*ap = strsep(&cp, "=")) != NULL; ) {
372 			if (**ap != '\0')
373 				ap++;
374 		}
375 		if (ap != &pair[2])
376 			goto parse_error;
377 
378 		tp = pair[1] + strlen(pair[1]);
379 		while ((*tp == ' ' || *tp == '\t') && tp >= pair[1])
380 			*tp-- = '\0';
381 
382 		if (strcasecmp(pair[0], "anchor") == 0) {
383 			if (!pair[1][0] || strlcpy(anchorname, pair[1],
384 			    sizeof(anchorname)) >= sizeof(anchorname))
385 				goto parse_error;
386 		}
387 		if (strcasecmp(pair[0], "table") == 0) {
388 			if (!pair[1][0] || strlcpy(tablename, pair[1],
389 			    sizeof(tablename)) >= sizeof(tablename))
390 				goto parse_error;
391 		}
392 	} while (!feof(f) && !ferror(f));
393 	fclose(f);
394 	return (0);
395 
396 parse_error:
397 	fclose(f);
398 	syslog(LOG_ERR, "parse error, line %d of %s", i, PATH_CONFFILE);
399 	return (1);
400 }
401 
402 
403 /*
404  * splatter a file to stdout - max line length of 1024,
405  * used for spitting message files at users to tell them
406  * they've been bad or we're unavailable.
407  */
408 static void
print_message(const char * filename)409 print_message(const char *filename)
410 {
411 	char	 buf[1024];
412 	FILE	*f;
413 
414 	if ((f = fopen(filename, "r")) == NULL)
415 		return; /* fail silently, we don't care if it isn't there */
416 
417 	do {
418 		if (fgets(buf, sizeof(buf), f) == NULL) {
419 			fflush(stdout);
420 			fclose(f);
421 			return;
422 		}
423 	} while (fputs(buf, stdout) != EOF && !feof(f));
424 	fflush(stdout);
425 	fclose(f);
426 }
427 
428 /*
429  * allowed_luser checks to see if user "luser" is allowed to
430  * use this gateway by virtue of being listed in an allowed
431  * users file, namely /etc/authpf/authpf.allow .
432  *
433  * If /etc/authpf/authpf.allow does not exist, then we assume that
434  * all users who are allowed in by sshd(8) are permitted to
435  * use this gateway. If /etc/authpf/authpf.allow does exist, then a
436  * user must be listed if the connection is to continue, else
437  * the session terminates in the same manner as being banned.
438  */
439 static int
allowed_luser(const char * user)440 allowed_luser(const char *user)
441 {
442 	char	*buf, *lbuf;
443 	int	 matched;
444 	size_t	 len;
445 	FILE	*f;
446 
447 	if ((f = fopen(PATH_ALLOWFILE, "r")) == NULL) {
448 		if (errno == ENOENT) {
449 			/*
450 			 * allowfile doesn't exist, thus this gateway
451 			 * isn't restricted to certain users...
452 			 */
453 			return (1);
454 		}
455 
456 		/*
457 		 * user may in fact be allowed, but we can't open
458 		 * the file even though it's there. probably a config
459 		 * problem.
460 		 */
461 		syslog(LOG_ERR, "cannot open allowed users file %s (%s)",
462 		    PATH_ALLOWFILE, strerror(errno));
463 		return (0);
464 	} else {
465 		/*
466 		 * /etc/authpf/authpf.allow exists, thus we do a linear
467 		 * search to see if they are allowed.
468 		 * also, if username "*" exists, then this is a
469 		 * "public" gateway, such as it is, so let
470 		 * everyone use it.
471 		 */
472 		lbuf = NULL;
473 		while ((buf = fgetln(f, &len))) {
474 			if (buf[len - 1] == '\n')
475 				buf[len - 1] = '\0';
476 			else {
477 				if ((lbuf = (char *)malloc(len + 1)) == NULL)
478 					err(1, NULL);
479 				memcpy(lbuf, buf, len);
480 				lbuf[len] = '\0';
481 				buf = lbuf;
482 			}
483 
484 			matched = strcmp(user, buf) == 0 || strcmp("*", buf) == 0;
485 
486 			if (lbuf != NULL) {
487 				free(lbuf);
488 				lbuf = NULL;
489 			}
490 
491 			if (matched)
492 				return (1); /* matched an allowed username */
493 		}
494 		syslog(LOG_INFO, "denied access to %s: not listed in %s",
495 		    user, PATH_ALLOWFILE);
496 
497 		fputs("\n\nSorry, you are not allowed to use this facility!\n",
498 		      stdout);
499 	}
500 	fflush(stdout);
501 	return (0);
502 }
503 
504 /*
505  * check_luser checks to see if user "luser" has been banned
506  * from using us by virtue of having an file of the same name
507  * in the "luserdir" directory.
508  *
509  * If the user has been banned, we copy the contents of the file
510  * to the user's screen. (useful for telling the user what to
511  * do to get un-banned, or just to tell them they aren't
512  * going to be un-banned.)
513  */
514 static int
check_luser(const char * userdir,const char * user)515 check_luser(const char *userdir, const char *user)
516 {
517 	FILE	*f;
518 	int	 n;
519 	char	 tmp[MAXPATHLEN];
520 
521 	n = snprintf(tmp, sizeof(tmp), "%s/%s", userdir, user);
522 	if (n < 0 || (u_int)n >= sizeof(tmp)) {
523 		syslog(LOG_ERR, "provided banned directory line too long (%s)",
524 		    userdir);
525 		return (0);
526 	}
527 	if ((f = fopen(tmp, "r")) == NULL) {
528 		if (errno == ENOENT) {
529 			/*
530 			 * file or dir doesn't exist, so therefore
531 			 * this luser isn't banned..  all is well
532 			 */
533 			return (1);
534 		} else {
535 			/*
536 			 * user may in fact be banned, but we can't open the
537 			 * file even though it's there. probably a config
538 			 * problem.
539 			 */
540 			syslog(LOG_ERR, "cannot open banned file %s (%s)",
541 			    tmp, strerror(errno));
542 			return (0);
543 		}
544 	} else {
545 		/*
546 		 * user is banned - spit the file at them to
547 		 * tell what they can do and where they can go.
548 		 */
549 		syslog(LOG_INFO, "denied access to %s: %s exists",
550 		    luser, tmp);
551 
552 		/* reuse tmp */
553 		strlcpy(tmp, "\n\n-**- Sorry, you have been banned! -**-\n\n",
554 		    sizeof(tmp));
555 		while (fputs(tmp, stdout) != EOF && !feof(f)) {
556 			if (fgets(tmp, sizeof(tmp), f) == NULL) {
557 				fflush(stdout);
558 				fclose(f);
559 				return (0);
560 			}
561 		}
562 		fclose(f);
563 	}
564 	fflush(stdout);
565 	return (0);
566 }
567 
568 /*
569  * Search for rulesets left by other authpf processes (either because they
570  * died ungracefully or were terminated) and remove them.
571  */
572 static int
remove_stale_rulesets(void)573 remove_stale_rulesets(void)
574 {
575 	struct pfioc_ruleset	 prs;
576 	u_int32_t		 nr, mnr;
577 
578 	memset(&prs, 0, sizeof(prs));
579 	strlcpy(prs.path, anchorname, sizeof(prs.path));
580 	if (ioctl(dev_fd, DIOCGETRULESETS, &prs)) {
581 		if (errno == EINVAL)
582 			return (0);
583 		else
584 			return (1);
585 	}
586 
587 	mnr = prs.nr;
588 	nr = 0;
589 	while (nr < mnr) {
590 		char	*s, *t;
591 		pid_t	 pid;
592 
593 		prs.nr = nr;
594 		if (ioctl(dev_fd, DIOCGETRULESET, &prs))
595 			return (1);
596 		errno = 0;
597 		if ((t = strchr(prs.name, '(')) == NULL)
598 			t = prs.name;
599 		else
600 			t++;
601 		pid = strtoul(t, &s, 10);
602 		if (!prs.name[0] || errno ||
603 		    (*s && (t == prs.name || *s != ')')))
604 			return (1);
605 		if (kill(pid, 0) && errno != EPERM) {
606 			int			i;
607 			struct pfioc_trans_e	t_e[PF_RULESET_MAX+1];
608 			struct pfioc_trans	t_local;
609 
610 			bzero(&t_local, sizeof(t_local));
611 			bzero(t_e, sizeof(t_e));
612 			t_local.size = PF_RULESET_MAX+1;
613 			t_local.esize = sizeof(t_e[0]);
614 			t_local.array = t_e;
615 			for (i = 0; i < PF_RULESET_MAX+1; ++i) {
616 				t_e[i].rs_num = i;
617 				snprintf(t_e[i].anchor, sizeof(t_e[i].anchor),
618 				    "%s/%s", anchorname, prs.name);
619 			}
620 			mnr--;
621 		} else
622 			nr++;
623 	}
624 	return (0);
625 }
626 
627 /*
628  * Add/remove filter entries for user "luser" from ip "ipsrc"
629  */
630 static int
change_filter(int add,const char * user,const char * his_ipsrc)631 change_filter(int add, const char *user, const char *his_ipsrc)
632 {
633 	const char *pargv[13] = {
634 		"pfctl", "-p", "/dev/pf", "-q", "-a", "anchor/ruleset",
635 		"-D", "user_ip=X", "-D", "user_id=X", "-f",
636 		"file", NULL
637 	};
638 	char	*fdpath = NULL, *userstr = NULL, *ipstr = NULL;
639 	char	*rsn = NULL, *fn = NULL;
640 	pid_t	pid;
641 	gid_t   gid;
642 	int	s;
643 
644 	if (user == NULL || !user[0] || his_ipsrc == NULL || !his_ipsrc[0]) {
645 		syslog(LOG_ERR, "invalid user/ipsrc");
646 		goto error;
647 	}
648 
649 	if (asprintf(&rsn, "%s/%s", anchorname, rulesetname) == -1)
650 		goto no_mem;
651 	if (asprintf(&fdpath, "/dev/fd/%d", dev_fd) == -1)
652 		goto no_mem;
653 	if (asprintf(&ipstr, "user_ip=%s", his_ipsrc) == -1)
654 		goto no_mem;
655 	if (asprintf(&userstr, "user_id=%s", user) == -1)
656 		goto no_mem;
657 
658 	if (add) {
659 		struct stat sb;
660 
661 		if (asprintf(&fn, "%s/%s/authpf.rules", PATH_USER_DIR, user)
662 		    == -1)
663 			goto no_mem;
664 		if (stat(fn, &sb) == -1) {
665 			free(fn);
666 			if ((fn = strdup(PATH_PFRULES)) == NULL)
667 				goto no_mem;
668 		}
669 	}
670 	pargv[2] = fdpath;
671 	pargv[5] = rsn;
672 	pargv[7] = userstr;
673 	pargv[9] = ipstr;
674 	if (!add)
675 		pargv[11] = "/dev/null";
676 	else
677 		pargv[11] = fn;
678 
679 	switch (pid = fork()) {
680 	case -1:
681 		syslog(LOG_ERR, "fork failed");
682 		goto error;
683 	case 0:
684 		/* revoke group privs before exec */
685 		gid = getgid();
686 		if (setregid(gid, gid) == -1) {
687 			err(1, "setregid");
688 		}
689 		execvp(PATH_PFCTL, __DECONST(char *const *, pargv));
690 		warn("exec of %s failed", PATH_PFCTL);
691 		_exit(1);
692 	}
693 
694 	/* parent */
695 	waitpid(pid, &s, 0);
696 	if (s != 0) {
697 		syslog(LOG_ERR, "pfctl exited abnormally");
698 		goto error;
699 	}
700 
701 	if (add) {
702 		gettimeofday(&Tstart, NULL);
703 		syslog(LOG_INFO, "allowing %s, user %s", his_ipsrc, user);
704 	} else {
705 		gettimeofday(&Tend, NULL);
706 		syslog(LOG_INFO, "removed %s, user %s - duration %ld seconds",
707 		    his_ipsrc, user, Tend.tv_sec - Tstart.tv_sec);
708 	}
709 	return (0);
710 no_mem:
711 	syslog(LOG_ERR, "malloc failed");
712 error:
713 	free(fdpath);
714 	free(rsn);
715 	free(userstr);
716 	free(ipstr);
717 	free(fn);
718 	return (-1);
719 }
720 
721 /*
722  * Add/remove this IP from the "authpf_users" table.
723  */
724 static int
change_table(int add,const char * his_ipsrc)725 change_table(int add, const char *his_ipsrc)
726 {
727 	struct pfioc_table	io;
728 	struct pfr_addr		addr;
729 
730 	bzero(&io, sizeof(io));
731 	strlcpy(io.pfrio_table.pfrt_name, tablename,
732 	    sizeof(io.pfrio_table.pfrt_name));
733 	io.pfrio_buffer = &addr;
734 	io.pfrio_esize = sizeof(addr);
735 	io.pfrio_size = 1;
736 
737 	bzero(&addr, sizeof(addr));
738 	if (his_ipsrc == NULL || !his_ipsrc[0])
739 		return (-1);
740 	if (inet_pton(AF_INET, his_ipsrc, &addr.pfra_ip4addr) == 1) {
741 		addr.pfra_af = AF_INET;
742 		addr.pfra_net = 32;
743 	} else if (inet_pton(AF_INET6, his_ipsrc, &addr.pfra_ip6addr) == 1) {
744 		addr.pfra_af = AF_INET6;
745 		addr.pfra_net = 128;
746 	} else {
747 		syslog(LOG_ERR, "invalid his_ipsrc");
748 		return (-1);
749 	}
750 
751 	if (ioctl(dev_fd, add ? DIOCRADDADDRS : DIOCRDELADDRS, &io) &&
752 	    errno != ESRCH) {
753 		syslog(LOG_ERR, "cannot %s %s from table %s: %s",
754 		    add ? "add" : "remove", his_ipsrc, tablename,
755 		    strerror(errno));
756 		return (-1);
757 	}
758 	return (0);
759 }
760 
761 /*
762  * This is to kill off states that would otherwise be left behind stateful
763  * rules. This means we don't need to allow in more traffic than we really
764  * want to, since we don't have to worry about any luser sessions lasting
765  * longer than their ssh session. This function is based on
766  * pfctl_kill_states from pfctl.
767  */
768 static void
authpf_kill_states(void)769 authpf_kill_states(void)
770 {
771 	struct pfioc_state_kill	psk;
772 	struct pf_addr target;
773 
774 	memset(&psk, 0, sizeof(psk));
775 	memset(&target, 0, sizeof(target));
776 
777 	if (inet_pton(AF_INET, ipsrc, &target.v4) == 1)
778 		psk.psk_af = AF_INET;
779 	else if (inet_pton(AF_INET6, ipsrc, &target.v6) == 1)
780 		psk.psk_af = AF_INET6;
781 	else {
782 		syslog(LOG_ERR, "inet_pton(%s) failed", ipsrc);
783 		return;
784 	}
785 
786 	/* Kill all states from ipsrc */
787 	memcpy(&psk.psk_src.addr.v.a.addr, &target,
788 	    sizeof(psk.psk_src.addr.v.a.addr));
789 	memset(&psk.psk_src.addr.v.a.mask, 0xff,
790 	    sizeof(psk.psk_src.addr.v.a.mask));
791 	if (ioctl(dev_fd, DIOCKILLSTATES, &psk))
792 		syslog(LOG_ERR, "DIOCKILLSTATES failed (%m)");
793 
794 	/* Kill all states to ipsrc */
795 	memset(&psk.psk_src, 0, sizeof(psk.psk_src));
796 	memcpy(&psk.psk_dst.addr.v.a.addr, &target,
797 	    sizeof(psk.psk_dst.addr.v.a.addr));
798 	memset(&psk.psk_dst.addr.v.a.mask, 0xff,
799 	    sizeof(psk.psk_dst.addr.v.a.mask));
800 	if (ioctl(dev_fd, DIOCKILLSTATES, &psk))
801 		syslog(LOG_ERR, "DIOCKILLSTATES failed (%m)");
802 }
803 
804 /* signal handler that makes us go away properly */
805 static void
need_death(int signo __unused)806 need_death(int signo __unused)
807 {
808 	want_death = 1;
809 }
810 
811 /*
812  * function that removes our stuff when we go away.
813  */
814 static __dead void
do_death(int active)815 do_death(int active)
816 {
817 	int	ret = 0;
818 
819 	if (active) {
820 		change_filter(0, luser, ipsrc);
821 		change_table(0, ipsrc);
822 		authpf_kill_states();
823 		remove_stale_rulesets();
824 	}
825 	if (pidfile[0] && (pidfp != NULL))
826 		if (unlink(pidfile) == -1)
827 			syslog(LOG_ERR, "cannot unlink %s (%m)", pidfile);
828 	exit(ret);
829 }
830