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