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/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 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 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 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 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 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 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 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 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 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 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 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 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