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