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