1 /* $OpenBSD: authpf.c,v 1.112 2009/01/10 19:08:53 miod Exp $ */
2
3 /*
4 * Copyright (C) 1998 - 2007 Bob Beck ([email protected]).
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
19 #include <sys/cdefs.h>
20 __FBSDID("$FreeBSD$");
21
22 #include <sys/types.h>
23 #include <sys/file.h>
24 #include <sys/ioctl.h>
25 #include <sys/socket.h>
26 #include <sys/stat.h>
27 #include <sys/time.h>
28 #include <sys/wait.h>
29
30 #include <net/if.h>
31 #include <net/pfvar.h>
32 #include <arpa/inet.h>
33
34 #include <err.h>
35 #include <errno.h>
36 #ifdef __FreeBSD__
37 #include <inttypes.h>
38 #endif
39 #include <libpfctl.h>
40 #include <login_cap.h>
41 #include <pwd.h>
42 #include <grp.h>
43 #include <signal.h>
44 #include <stdio.h>
45 #include <stdlib.h>
46 #include <string.h>
47 #include <syslog.h>
48 #include <unistd.h>
49
50 #include "pathnames.h"
51
52 static int read_config(FILE *);
53 static void print_message(const char *);
54 static int allowed_luser(struct passwd *);
55 static int check_luser(const char *, char *);
56 static int remove_stale_rulesets(void);
57 static int recursive_ruleset_purge(char *, char *);
58 static int change_filter(int, const char *, const char *);
59 static int change_table(int, const char *);
60 static void authpf_kill_states(void);
61
62 int dev; /* pf device */
63 char anchorname[PF_ANCHOR_NAME_SIZE] = "authpf";
64 char rulesetname[MAXPATHLEN - PF_ANCHOR_NAME_SIZE - 2];
65 char tablename[PF_TABLE_NAME_SIZE] = "authpf_users";
66 int user_ip = 1; /* controls whether $user_ip is set */
67
68 FILE *pidfp;
69 int pidfd = -1;
70 char luser[MAXLOGNAME]; /* username */
71 char ipsrc[256]; /* ip as a string */
72 char pidfile[MAXPATHLEN]; /* we save pid in this file. */
73
74 struct timeval Tstart, Tend; /* start and end times of session */
75
76 volatile sig_atomic_t want_death;
77 static void need_death(int signo);
78 #ifdef __FreeBSD__
79 static __dead2 void do_death(int);
80 #else
81 static __dead void do_death(int);
82 #endif
83 extern char *__progname; /* program name */
84
85 /*
86 * User shell for authenticating gateways. Sole purpose is to allow
87 * a user to ssh to a gateway, and have the gateway modify packet
88 * filters to allow access, then remove access when the user finishes
89 * up. Meant to be used only from ssh(1) connections.
90 */
91 int
main(void)92 main(void)
93 {
94 int lockcnt = 0, n;
95 FILE *config;
96 struct in6_addr ina;
97 struct passwd *pw;
98 char *cp;
99 gid_t gid;
100 uid_t uid;
101 const char *shell;
102 login_cap_t *lc;
103
104 if (strcmp(__progname, "-authpf-noip") == 0)
105 user_ip = 0;
106
107 config = fopen(PATH_CONFFILE, "r");
108 if (config == NULL) {
109 syslog(LOG_ERR, "cannot open %s (%m)", PATH_CONFFILE);
110 exit(1);
111 }
112
113 if ((cp = getenv("SSH_TTY")) == NULL) {
114 syslog(LOG_ERR, "non-interactive session connection for authpf");
115 exit(1);
116 }
117
118 if ((cp = getenv("SSH_CLIENT")) == NULL) {
119 syslog(LOG_ERR, "cannot determine connection source");
120 exit(1);
121 }
122
123 if (strlcpy(ipsrc, cp, sizeof(ipsrc)) >= sizeof(ipsrc)) {
124 syslog(LOG_ERR, "SSH_CLIENT variable too long");
125 exit(1);
126 }
127 cp = strchr(ipsrc, ' ');
128 if (!cp) {
129 syslog(LOG_ERR, "corrupt SSH_CLIENT variable %s", ipsrc);
130 exit(1);
131 }
132 *cp = '\0';
133 if (inet_pton(AF_INET, ipsrc, &ina) != 1 &&
134 inet_pton(AF_INET6, ipsrc, &ina) != 1) {
135 syslog(LOG_ERR,
136 "cannot determine IP from SSH_CLIENT %s", ipsrc);
137 exit(1);
138 }
139 /* open the pf device */
140 dev = open(PATH_DEVFILE, O_RDWR);
141 if (dev == -1) {
142 syslog(LOG_ERR, "cannot open packet filter device (%m)");
143 goto die;
144 }
145
146 uid = getuid();
147 pw = getpwuid(uid);
148 if (pw == NULL) {
149 syslog(LOG_ERR, "cannot find user for uid %u", uid);
150 goto die;
151 }
152
153 if ((lc = login_getclass(pw->pw_class)) != NULL)
154 shell = login_getcapstr(lc, "shell", pw->pw_shell,
155 pw->pw_shell);
156 else
157 shell = pw->pw_shell;
158
159 #ifndef __FreeBSD__
160 login_close(lc);
161 #endif
162
163 if (strcmp(shell, PATH_AUTHPF_SHELL) &&
164 strcmp(shell, PATH_AUTHPF_SHELL_NOIP)) {
165 syslog(LOG_ERR, "wrong shell for user %s, uid %u",
166 pw->pw_name, pw->pw_uid);
167 #ifdef __FreeBSD__
168 login_close(lc);
169 #else
170 if (shell != pw->pw_shell)
171 free(shell);
172 #endif
173 goto die;
174 }
175
176 #ifdef __FreeBSD__
177 login_close(lc);
178 #else
179 if (shell != pw->pw_shell)
180 free(shell);
181 #endif
182
183 /*
184 * Paranoia, but this data _does_ come from outside authpf, and
185 * truncation would be bad.
186 */
187 if (strlcpy(luser, pw->pw_name, sizeof(luser)) >= sizeof(luser)) {
188 syslog(LOG_ERR, "username too long: %s", pw->pw_name);
189 goto die;
190 }
191
192 if ((n = snprintf(rulesetname, sizeof(rulesetname), "%s(%ld)",
193 luser, (long)getpid())) < 0 || (u_int)n >= sizeof(rulesetname)) {
194 syslog(LOG_INFO, "%s(%ld) too large, ruleset name will be %ld",
195 luser, (long)getpid(), (long)getpid());
196 if ((n = snprintf(rulesetname, sizeof(rulesetname), "%ld",
197 (long)getpid())) < 0 || (u_int)n >= sizeof(rulesetname)) {
198 syslog(LOG_ERR, "pid too large for ruleset name");
199 goto die;
200 }
201 }
202
203
204 /* Make our entry in /var/authpf as ipaddr or username */
205 n = snprintf(pidfile, sizeof(pidfile), "%s/%s",
206 PATH_PIDFILE, user_ip ? ipsrc : luser);
207 if (n < 0 || (u_int)n >= sizeof(pidfile)) {
208 syslog(LOG_ERR, "path to pidfile too long");
209 goto die;
210 }
211
212 signal(SIGTERM, need_death);
213 signal(SIGINT, need_death);
214 signal(SIGALRM, need_death);
215 signal(SIGPIPE, need_death);
216 signal(SIGHUP, need_death);
217 signal(SIGQUIT, need_death);
218 signal(SIGTSTP, need_death);
219
220 /*
221 * If someone else is already using this ip, then this person
222 * wants to switch users - so kill the old process and exit
223 * as well.
224 *
225 * Note, we could print a message and tell them to log out, but the
226 * usual case of this is that someone has left themselves logged in,
227 * with the authenticated connection iconized and someone else walks
228 * up to use and automatically logs in before using. If this just
229 * gets rid of the old one silently, the new user never knows they
230 * could have used someone else's old authentication. If we
231 * tell them to log out before switching users it is an invitation
232 * for abuse.
233 */
234
235 do {
236 int save_errno, otherpid = -1;
237 char otherluser[MAXLOGNAME];
238
239 if ((pidfd = open(pidfile, O_RDWR|O_CREAT, 0644)) == -1 ||
240 (pidfp = fdopen(pidfd, "r+")) == NULL) {
241 if (pidfd != -1)
242 close(pidfd);
243 syslog(LOG_ERR, "cannot open or create %s: %s", pidfile,
244 strerror(errno));
245 goto die;
246 }
247
248 if (flock(fileno(pidfp), LOCK_EX|LOCK_NB) == 0)
249 break;
250 save_errno = errno;
251
252 /* Mark our pid, and username to our file. */
253
254 rewind(pidfp);
255 /* 31 == MAXLOGNAME - 1 */
256 if (fscanf(pidfp, "%d\n%31s\n", &otherpid, otherluser) != 2)
257 otherpid = -1;
258 syslog(LOG_DEBUG, "tried to lock %s, in use by pid %d: %s",
259 pidfile, otherpid, strerror(save_errno));
260
261 if (otherpid > 0) {
262 syslog(LOG_INFO,
263 "killing prior auth (pid %d) of %s by user %s",
264 otherpid, ipsrc, otherluser);
265 if (kill((pid_t) otherpid, SIGTERM) == -1) {
266 syslog(LOG_INFO,
267 "could not kill process %d: (%m)",
268 otherpid);
269 }
270 }
271
272 /*
273 * We try to kill the previous process and acquire the lock
274 * for 10 seconds, trying once a second. if we can't after
275 * 10 attempts we log an error and give up.
276 */
277 if (want_death || ++lockcnt > 10) {
278 if (!want_death)
279 syslog(LOG_ERR, "cannot kill previous authpf (pid %d)",
280 otherpid);
281 fclose(pidfp);
282 pidfp = NULL;
283 pidfd = -1;
284 goto dogdeath;
285 }
286 sleep(1);
287
288 /* re-open, and try again. The previous authpf process
289 * we killed above should unlink the file and release
290 * it's lock, giving us a chance to get it now
291 */
292 fclose(pidfp);
293 pidfp = NULL;
294 pidfd = -1;
295 } while (1);
296
297 /* whack the group list */
298 gid = getegid();
299 if (setgroups(1, &gid) == -1) {
300 syslog(LOG_INFO, "setgroups: %s", strerror(errno));
301 do_death(0);
302 }
303
304 /* revoke privs */
305 uid = getuid();
306 if (setresuid(uid, uid, uid) == -1) {
307 syslog(LOG_INFO, "setresuid: %s", strerror(errno));
308 do_death(0);
309 }
310 openlog("authpf", LOG_PID | LOG_NDELAY, LOG_DAEMON);
311
312 if (!check_luser(PATH_BAN_DIR, luser) || !allowed_luser(pw)) {
313 syslog(LOG_INFO, "user %s prohibited", luser);
314 do_death(0);
315 }
316
317 if (read_config(config)) {
318 syslog(LOG_ERR, "invalid config file %s", PATH_CONFFILE);
319 do_death(0);
320 }
321
322 if (remove_stale_rulesets()) {
323 syslog(LOG_INFO, "error removing stale rulesets");
324 do_death(0);
325 }
326
327 /* We appear to be making headway, so actually mark our pid */
328 rewind(pidfp);
329 fprintf(pidfp, "%ld\n%s\n", (long)getpid(), luser);
330 fflush(pidfp);
331 (void) ftruncate(fileno(pidfp), ftello(pidfp));
332
333 if (change_filter(1, luser, ipsrc) == -1) {
334 printf("Unable to modify filters\r\n");
335 do_death(0);
336 }
337 if (user_ip && change_table(1, ipsrc) == -1) {
338 printf("Unable to modify table\r\n");
339 change_filter(0, luser, ipsrc);
340 do_death(0);
341 }
342
343 while (1) {
344 printf("\r\nHello %s. ", luser);
345 printf("You are authenticated from host \"%s\"\r\n", ipsrc);
346 setproctitle("%s@%s", luser, ipsrc);
347 print_message(PATH_MESSAGE);
348 while (1) {
349 sleep(10);
350 if (want_death)
351 do_death(1);
352 }
353 }
354
355 /* NOTREACHED */
356 dogdeath:
357 printf("\r\n\r\nSorry, this service is currently unavailable due to ");
358 printf("technical difficulties\r\n\r\n");
359 print_message(PATH_PROBLEM);
360 printf("\r\nYour authentication process (pid %ld) was unable to run\n",
361 (long)getpid());
362 sleep(180); /* them lusers read reaaaaal slow */
363 die:
364 do_death(0);
365 }
366
367 /*
368 * reads config file in PATH_CONFFILE to set optional behaviours up
369 */
370 static int
read_config(FILE * f)371 read_config(FILE *f)
372 {
373 char buf[1024];
374 int i = 0;
375
376 do {
377 char **ap;
378 char *pair[4], *cp, *tp;
379 int len;
380
381 if (fgets(buf, sizeof(buf), f) == NULL) {
382 fclose(f);
383 return (0);
384 }
385 i++;
386 len = strlen(buf);
387 if (len == 0)
388 continue;
389 if (buf[len - 1] != '\n' && !feof(f)) {
390 syslog(LOG_ERR, "line %d too long in %s", i,
391 PATH_CONFFILE);
392 return (1);
393 }
394 buf[len - 1] = '\0';
395
396 for (cp = buf; *cp == ' ' || *cp == '\t'; cp++)
397 ; /* nothing */
398
399 if (!*cp || *cp == '#' || *cp == '\n')
400 continue;
401
402 for (ap = pair; ap < &pair[3] &&
403 (*ap = strsep(&cp, "=")) != NULL; ) {
404 if (**ap != '\0')
405 ap++;
406 }
407 if (ap != &pair[2])
408 goto parse_error;
409
410 tp = pair[1] + strlen(pair[1]);
411 while ((*tp == ' ' || *tp == '\t') && tp >= pair[1])
412 *tp-- = '\0';
413
414 if (strcasecmp(pair[0], "anchor") == 0) {
415 if (!pair[1][0] || strlcpy(anchorname, pair[1],
416 sizeof(anchorname)) >= sizeof(anchorname))
417 goto parse_error;
418 }
419 if (strcasecmp(pair[0], "table") == 0) {
420 if (!pair[1][0] || strlcpy(tablename, pair[1],
421 sizeof(tablename)) >= sizeof(tablename))
422 goto parse_error;
423 }
424 } while (!feof(f) && !ferror(f));
425 fclose(f);
426 return (0);
427
428 parse_error:
429 fclose(f);
430 syslog(LOG_ERR, "parse error, line %d of %s", i, PATH_CONFFILE);
431 return (1);
432 }
433
434
435 /*
436 * splatter a file to stdout - max line length of 1024,
437 * used for spitting message files at users to tell them
438 * they've been bad or we're unavailable.
439 */
440 static void
print_message(const char * filename)441 print_message(const char *filename)
442 {
443 char buf[1024];
444 FILE *f;
445
446 if ((f = fopen(filename, "r")) == NULL)
447 return; /* fail silently, we don't care if it isn't there */
448
449 do {
450 if (fgets(buf, sizeof(buf), f) == NULL) {
451 fflush(stdout);
452 fclose(f);
453 return;
454 }
455 } while (fputs(buf, stdout) != EOF && !feof(f));
456 fflush(stdout);
457 fclose(f);
458 }
459
460 /*
461 * allowed_luser checks to see if user "luser" is allowed to
462 * use this gateway by virtue of being listed in an allowed
463 * users file, namely /etc/authpf/authpf.allow .
464 * Users may be listed by <username>, %<group>, or @<login_class>.
465 *
466 * If /etc/authpf/authpf.allow does not exist, then we assume that
467 * all users who are allowed in by sshd(8) are permitted to
468 * use this gateway. If /etc/authpf/authpf.allow does exist, then a
469 * user must be listed if the connection is to continue, else
470 * the session terminates in the same manner as being banned.
471 */
472 static int
allowed_luser(struct passwd * pw)473 allowed_luser(struct passwd *pw)
474 {
475 char *buf,*lbuf;
476 int matched;
477 size_t len;
478 FILE *f;
479
480 if ((f = fopen(PATH_ALLOWFILE, "r")) == NULL) {
481 if (errno == ENOENT) {
482 /*
483 * allowfile doesn't exist, thus this gateway
484 * isn't restricted to certain users...
485 */
486 return (1);
487 }
488
489 /*
490 * luser may in fact be allowed, but we can't open
491 * the file even though it's there. probably a config
492 * problem.
493 */
494 syslog(LOG_ERR, "cannot open allowed users file %s (%s)",
495 PATH_ALLOWFILE, strerror(errno));
496 return (0);
497 } else {
498 /*
499 * /etc/authpf/authpf.allow exists, thus we do a linear
500 * search to see if they are allowed.
501 * also, if username "*" exists, then this is a
502 * "public" gateway, such as it is, so let
503 * everyone use it.
504 */
505 int gl_init = 0, ngroups = NGROUPS + 1;
506 gid_t groups[NGROUPS + 1];
507
508 lbuf = NULL;
509 matched = 0;
510
511 while ((buf = fgetln(f, &len))) {
512
513 if (buf[len - 1] == '\n')
514 buf[len - 1] = '\0';
515 else {
516 if ((lbuf = (char *)malloc(len + 1)) == NULL)
517 err(1, NULL);
518 memcpy(lbuf, buf, len);
519 lbuf[len] = '\0';
520 buf = lbuf;
521 }
522
523 if (buf[0] == '@') {
524 /* check login class */
525 if (strcmp(pw->pw_class, buf + 1) == 0)
526 matched++;
527 } else if (buf[0] == '%') {
528 /* check group membership */
529 int cnt;
530 struct group *group;
531
532 if ((group = getgrnam(buf + 1)) == NULL) {
533 syslog(LOG_ERR,
534 "invalid group '%s' in %s (%s)",
535 buf + 1, PATH_ALLOWFILE,
536 strerror(errno));
537 return (0);
538 }
539
540 if (!gl_init) {
541 (void) getgrouplist(pw->pw_name,
542 pw->pw_gid, groups, &ngroups);
543 gl_init++;
544 }
545
546 for ( cnt = 0; cnt < ngroups; cnt++) {
547 if (group->gr_gid == groups[cnt]) {
548 matched++;
549 break;
550 }
551 }
552 } else {
553 /* check username and wildcard */
554 matched = strcmp(pw->pw_name, buf) == 0 ||
555 strcmp("*", buf) == 0;
556 }
557
558 if (lbuf != NULL) {
559 free(lbuf);
560 lbuf = NULL;
561 }
562
563 if (matched)
564 return (1); /* matched an allowed user/group */
565 }
566 syslog(LOG_INFO, "denied access to %s: not listed in %s",
567 pw->pw_name, PATH_ALLOWFILE);
568
569 /* reuse buf */
570 sprintf(buf, "%s", "\n\nSorry, you are not allowed to use this facility!\n");
571 fputs(buf, stdout);
572 }
573 fflush(stdout);
574 return (0);
575 }
576
577 /*
578 * check_luser checks to see if user "luser" has been banned
579 * from using us by virtue of having an file of the same name
580 * in the "luserdir" directory.
581 *
582 * If the user has been banned, we copy the contents of the file
583 * to the user's screen. (useful for telling the user what to
584 * do to get un-banned, or just to tell them they aren't
585 * going to be un-banned.)
586 */
587 static int
check_luser(const char * luserdir,char * l_user)588 check_luser(const char *luserdir, char *l_user)
589 {
590 FILE *f;
591 int n;
592 char tmp[MAXPATHLEN];
593
594 n = snprintf(tmp, sizeof(tmp), "%s/%s", luserdir, l_user);
595 if (n < 0 || (u_int)n >= sizeof(tmp)) {
596 syslog(LOG_ERR, "provided banned directory line too long (%s)",
597 luserdir);
598 return (0);
599 }
600 if ((f = fopen(tmp, "r")) == NULL) {
601 if (errno == ENOENT) {
602 /*
603 * file or dir doesn't exist, so therefore
604 * this luser isn't banned.. all is well
605 */
606 return (1);
607 } else {
608 /*
609 * luser may in fact be banned, but we can't open the
610 * file even though it's there. probably a config
611 * problem.
612 */
613 syslog(LOG_ERR, "cannot open banned file %s (%s)",
614 tmp, strerror(errno));
615 return (0);
616 }
617 } else {
618 /*
619 * luser is banned - spit the file at them to
620 * tell what they can do and where they can go.
621 */
622 syslog(LOG_INFO, "denied access to %s: %s exists",
623 l_user, tmp);
624
625 /* reuse tmp */
626 strlcpy(tmp, "\n\n-**- Sorry, you have been banned! -**-\n\n",
627 sizeof(tmp));
628 while (fputs(tmp, stdout) != EOF && !feof(f)) {
629 if (fgets(tmp, sizeof(tmp), f) == NULL) {
630 fflush(stdout);
631 fclose(f);
632 return (0);
633 }
634 }
635 fclose(f);
636 }
637 fflush(stdout);
638 return (0);
639 }
640
641 /*
642 * Search for rulesets left by other authpf processes (either because they
643 * died ungracefully or were terminated) and remove them.
644 */
645 static int
remove_stale_rulesets(void)646 remove_stale_rulesets(void)
647 {
648 struct pfioc_ruleset prs;
649 u_int32_t nr;
650
651 memset(&prs, 0, sizeof(prs));
652 strlcpy(prs.path, anchorname, sizeof(prs.path));
653 if (ioctl(dev, DIOCGETRULESETS, &prs)) {
654 if (errno == EINVAL)
655 return (0);
656 else
657 return (1);
658 }
659
660 nr = prs.nr;
661 while (nr) {
662 char *s, *t;
663 pid_t pid;
664
665 prs.nr = nr - 1;
666 if (ioctl(dev, DIOCGETRULESET, &prs))
667 return (1);
668 errno = 0;
669 if ((t = strchr(prs.name, '(')) == NULL)
670 t = prs.name;
671 else
672 t++;
673 pid = strtoul(t, &s, 10);
674 if (!prs.name[0] || errno ||
675 (*s && (t == prs.name || *s != ')')))
676 return (1);
677 if ((kill(pid, 0) && errno != EPERM) || pid == getpid()) {
678 if (recursive_ruleset_purge(anchorname, prs.name))
679 return (1);
680 }
681 nr--;
682 }
683 return (0);
684 }
685
686 static int
recursive_ruleset_purge(char * an,char * rs)687 recursive_ruleset_purge(char *an, char *rs)
688 {
689 struct pfioc_trans_e *t_e = NULL;
690 struct pfioc_trans *t = NULL;
691 struct pfioc_ruleset *prs = NULL;
692 int i;
693
694
695 /* purge rules */
696 errno = 0;
697 if ((t = calloc(1, sizeof(struct pfioc_trans))) == NULL)
698 goto no_mem;
699 if ((t_e = calloc(PF_RULESET_MAX+1,
700 sizeof(struct pfioc_trans_e))) == NULL)
701 goto no_mem;
702 t->size = PF_RULESET_MAX+1;
703 t->esize = sizeof(struct pfioc_trans_e);
704 t->array = t_e;
705 for (i = 0; i < PF_RULESET_MAX+1; ++i) {
706 t_e[i].rs_num = i;
707 snprintf(t_e[i].anchor, sizeof(t_e[i].anchor), "%s/%s", an, rs);
708 }
709 t_e[PF_RULESET_MAX].rs_num = PF_RULESET_TABLE;
710 if ((ioctl(dev, DIOCXBEGIN, t) ||
711 ioctl(dev, DIOCXCOMMIT, t)) &&
712 errno != EINVAL)
713 goto cleanup;
714
715 /* purge any children */
716 if ((prs = calloc(1, sizeof(struct pfioc_ruleset))) == NULL)
717 goto no_mem;
718 snprintf(prs->path, sizeof(prs->path), "%s/%s", an, rs);
719 if (ioctl(dev, DIOCGETRULESETS, prs)) {
720 if (errno != EINVAL)
721 goto cleanup;
722 errno = 0;
723 } else {
724 int nr = prs->nr;
725
726 while (nr) {
727 prs->nr = 0;
728 if (ioctl(dev, DIOCGETRULESET, prs))
729 goto cleanup;
730
731 if (recursive_ruleset_purge(prs->path, prs->name))
732 goto cleanup;
733 nr--;
734 }
735 }
736
737 no_mem:
738 if (errno == ENOMEM)
739 syslog(LOG_ERR, "calloc failed");
740
741 cleanup:
742 free(t);
743 free(t_e);
744 free(prs);
745 return (errno);
746 }
747
748 /*
749 * Add/remove filter entries for user "luser" from ip "ipsrc"
750 */
751 static int
change_filter(int add,const char * l_user,const char * ip_src)752 change_filter(int add, const char *l_user, const char *ip_src)
753 {
754 char *fdpath = NULL, *userstr = NULL, *ipstr = NULL;
755 char *rsn = NULL, *fn = NULL;
756 pid_t pid;
757 gid_t gid;
758 int s;
759
760 if (add) {
761 struct stat sb;
762 char *pargv[13] = {
763 "pfctl", "-p", "/dev/pf", "-q", "-a", "anchor/ruleset",
764 "-D", "user_id=X", "-D", "user_ip=X", "-f", "file", NULL
765 };
766
767 if (l_user == NULL || !l_user[0] || ip_src == NULL || !ip_src[0]) {
768 syslog(LOG_ERR, "invalid luser/ipsrc");
769 goto error;
770 }
771
772 if (asprintf(&rsn, "%s/%s", anchorname, rulesetname) == -1)
773 goto no_mem;
774 if (asprintf(&fdpath, "/dev/fd/%d", dev) == -1)
775 goto no_mem;
776 if (asprintf(&ipstr, "user_ip=%s", ip_src) == -1)
777 goto no_mem;
778 if (asprintf(&userstr, "user_id=%s", l_user) == -1)
779 goto no_mem;
780 if (asprintf(&fn, "%s/%s/authpf.rules",
781 PATH_USER_DIR, l_user) == -1)
782 goto no_mem;
783 if (stat(fn, &sb) == -1) {
784 free(fn);
785 if ((fn = strdup(PATH_PFRULES)) == NULL)
786 goto no_mem;
787 }
788 pargv[2] = fdpath;
789 pargv[5] = rsn;
790 pargv[7] = userstr;
791 if (user_ip) {
792 pargv[9] = ipstr;
793 pargv[11] = fn;
794 } else {
795 pargv[8] = "-f";
796 pargv[9] = fn;
797 pargv[10] = NULL;
798 }
799
800 switch (pid = fork()) {
801 case -1:
802 syslog(LOG_ERR, "fork failed");
803 goto error;
804 case 0:
805 /* revoke group privs before exec */
806 gid = getgid();
807 if (setregid(gid, gid) == -1) {
808 err(1, "setregid");
809 }
810 execvp(PATH_PFCTL, pargv);
811 warn("exec of %s failed", PATH_PFCTL);
812 _exit(1);
813 }
814
815 /* parent */
816 waitpid(pid, &s, 0);
817 if (s != 0) {
818 syslog(LOG_ERR, "pfctl exited abnormally");
819 goto error;
820 }
821
822 gettimeofday(&Tstart, NULL);
823 syslog(LOG_INFO, "allowing %s, user %s", ip_src, l_user);
824 } else {
825 remove_stale_rulesets();
826
827 gettimeofday(&Tend, NULL);
828 syslog(LOG_INFO, "removed %s, user %s - duration %ju seconds",
829 ip_src, l_user, (uintmax_t)(Tend.tv_sec - Tstart.tv_sec));
830 }
831 return (0);
832 no_mem:
833 syslog(LOG_ERR, "malloc failed");
834 error:
835 free(fdpath);
836 free(rsn);
837 free(userstr);
838 free(ipstr);
839 free(fn);
840 return (-1);
841 }
842
843 /*
844 * Add/remove this IP from the "authpf_users" table.
845 */
846 static int
change_table(int add,const char * ip_src)847 change_table(int add, const char *ip_src)
848 {
849 struct pfioc_table io;
850 struct pfr_addr addr;
851
852 bzero(&io, sizeof(io));
853 strlcpy(io.pfrio_table.pfrt_name, tablename,
854 sizeof(io.pfrio_table.pfrt_name));
855 io.pfrio_buffer = &addr;
856 io.pfrio_esize = sizeof(addr);
857 io.pfrio_size = 1;
858
859 bzero(&addr, sizeof(addr));
860 if (ip_src == NULL || !ip_src[0])
861 return (-1);
862 if (inet_pton(AF_INET, ip_src, &addr.pfra_ip4addr) == 1) {
863 addr.pfra_af = AF_INET;
864 addr.pfra_net = 32;
865 } else if (inet_pton(AF_INET6, ip_src, &addr.pfra_ip6addr) == 1) {
866 addr.pfra_af = AF_INET6;
867 addr.pfra_net = 128;
868 } else {
869 syslog(LOG_ERR, "invalid ipsrc");
870 return (-1);
871 }
872
873 if (ioctl(dev, add ? DIOCRADDADDRS : DIOCRDELADDRS, &io) &&
874 errno != ESRCH) {
875 syslog(LOG_ERR, "cannot %s %s from table %s: %s",
876 add ? "add" : "remove", ip_src, tablename,
877 strerror(errno));
878 return (-1);
879 }
880 return (0);
881 }
882
883 /*
884 * This is to kill off states that would otherwise be left behind stateful
885 * rules. This means we don't need to allow in more traffic than we really
886 * want to, since we don't have to worry about any luser sessions lasting
887 * longer than their ssh session. This function is based on
888 * pfctl_kill_states from pfctl.
889 */
890 static void
authpf_kill_states(void)891 authpf_kill_states(void)
892 {
893 struct pfctl_kill kill;
894 struct pf_addr target;
895
896 memset(&kill, 0, sizeof(kill));
897 memset(&target, 0, sizeof(target));
898
899 if (inet_pton(AF_INET, ipsrc, &target.v4) == 1)
900 kill.af = AF_INET;
901 else if (inet_pton(AF_INET6, ipsrc, &target.v6) == 1)
902 kill.af = AF_INET6;
903 else {
904 syslog(LOG_ERR, "inet_pton(%s) failed", ipsrc);
905 return;
906 }
907
908 /* Kill all states from ipsrc */
909 memcpy(&kill.src.addr.v.a.addr, &target,
910 sizeof(kill.src.addr.v.a.addr));
911 memset(&kill.src.addr.v.a.mask, 0xff,
912 sizeof(kill.src.addr.v.a.mask));
913 if (pfctl_kill_states(dev, &kill, NULL))
914 syslog(LOG_ERR, "pfctl_kill_states() failed (%m)");
915
916 /* Kill all states to ipsrc */
917 memset(&kill.src, 0, sizeof(kill.src));
918 memcpy(&kill.dst.addr.v.a.addr, &target,
919 sizeof(kill.dst.addr.v.a.addr));
920 memset(&kill.dst.addr.v.a.mask, 0xff,
921 sizeof(kill.dst.addr.v.a.mask));
922 if (pfctl_kill_states(dev, &kill, NULL))
923 syslog(LOG_ERR, "pfctl_kill_states() failed (%m)");
924 }
925
926 /* signal handler that makes us go away properly */
927 static void
need_death(int signo __unused)928 need_death(int signo __unused)
929 {
930 want_death = 1;
931 }
932
933 /*
934 * function that removes our stuff when we go away.
935 */
936 #ifdef __FreeBSD__
937 static __dead2 void
938 #else
939 static __dead void
940 #endif
do_death(int active)941 do_death(int active)
942 {
943 int ret = 0;
944
945 if (active) {
946 change_filter(0, luser, ipsrc);
947 if (user_ip) {
948 change_table(0, ipsrc);
949 authpf_kill_states();
950 }
951 }
952 if (pidfile[0] && pidfd != -1)
953 if (unlink(pidfile) == -1)
954 syslog(LOG_ERR, "cannot unlink %s (%m)", pidfile);
955 exit(ret);
956 }
957