1 /* $OpenBSD: authpf.c,v 1.115 2010/09/02 14:01:04 sobrado 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 struct stat sb; 324 char *path_message; 325 printf("\r\nHello %s. ", luser); 326 printf("You are authenticated from host \"%s\"\r\n", ipsrc); 327 setproctitle("%s@%s", luser, ipsrc); 328 if (asprintf(&path_message, "%s/%s/authpf.message", 329 PATH_USER_DIR, luser) == -1) 330 do_death(1); 331 if (stat(path_message, &sb) == -1 || ! S_ISREG(sb.st_mode)) { 332 free(path_message); 333 if ((path_message = strdup(PATH_MESSAGE)) == NULL) 334 do_death(1); 335 } 336 print_message(path_message); 337 while (1) { 338 sleep(10); 339 if (want_death) 340 do_death(1); 341 } 342 } 343 344 /* NOTREACHED */ 345 dogdeath: 346 printf("\r\n\r\nSorry, this service is currently unavailable due to "); 347 printf("technical difficulties\r\n\r\n"); 348 print_message(PATH_PROBLEM); 349 printf("\r\nYour authentication process (pid %ld) was unable to run\n", 350 (long)getpid()); 351 sleep(180); /* them lusers read reaaaaal slow */ 352 die: 353 do_death(0); 354 } 355 356 /* 357 * reads config file in PATH_CONFFILE to set optional behaviours up 358 */ 359 static int 360 read_config(FILE *f) 361 { 362 char buf[1024]; 363 int i = 0; 364 365 do { 366 char **ap; 367 char *pair[4], *cp, *tp; 368 int len; 369 370 if (fgets(buf, sizeof(buf), f) == NULL) { 371 fclose(f); 372 return (0); 373 } 374 i++; 375 len = strlen(buf); 376 if (len == 0) 377 continue; 378 if (buf[len - 1] != '\n' && !feof(f)) { 379 syslog(LOG_ERR, "line %d too long in %s", i, 380 PATH_CONFFILE); 381 return (1); 382 } 383 buf[len - 1] = '\0'; 384 385 for (cp = buf; *cp == ' ' || *cp == '\t'; cp++) 386 ; /* nothing */ 387 388 if (!*cp || *cp == '#' || *cp == '\n') 389 continue; 390 391 for (ap = pair; ap < &pair[3] && 392 (*ap = strsep(&cp, "=")) != NULL; ) { 393 if (**ap != '\0') 394 ap++; 395 } 396 if (ap != &pair[2]) 397 goto parse_error; 398 399 tp = pair[1] + strlen(pair[1]); 400 while ((*tp == ' ' || *tp == '\t') && tp >= pair[1]) 401 *tp-- = '\0'; 402 403 if (strcasecmp(pair[0], "anchor") == 0) { 404 if (!pair[1][0] || strlcpy(anchorname, pair[1], 405 sizeof(anchorname)) >= sizeof(anchorname)) 406 goto parse_error; 407 } 408 if (strcasecmp(pair[0], "table") == 0) { 409 if (!pair[1][0] || strlcpy(tablename, pair[1], 410 sizeof(tablename)) >= sizeof(tablename)) 411 goto parse_error; 412 } 413 } while (!feof(f) && !ferror(f)); 414 fclose(f); 415 return (0); 416 417 parse_error: 418 fclose(f); 419 syslog(LOG_ERR, "parse error, line %d of %s", i, PATH_CONFFILE); 420 return (1); 421 } 422 423 424 /* 425 * splatter a file to stdout - max line length of 1024, 426 * used for spitting message files at users to tell them 427 * they've been bad or we're unavailable. 428 */ 429 static void 430 print_message(char *filename) 431 { 432 char buf[1024]; 433 FILE *f; 434 435 if ((f = fopen(filename, "r")) == NULL) 436 return; /* fail silently, we don't care if it isn't there */ 437 438 do { 439 if (fgets(buf, sizeof(buf), f) == NULL) { 440 fflush(stdout); 441 fclose(f); 442 return; 443 } 444 } while (fputs(buf, stdout) != EOF && !feof(f)); 445 fflush(stdout); 446 fclose(f); 447 } 448 449 /* 450 * allowed_luser checks to see if user "luser" is allowed to 451 * use this gateway by virtue of being listed in an allowed 452 * users file, namely /etc/authpf/authpf.allow . 453 * Users may be listed by <username>, %<group>, or @<login_class>. 454 * 455 * If /etc/authpf/authpf.allow does not exist, then we assume that 456 * all users who are allowed in by sshd(8) are permitted to 457 * use this gateway. If /etc/authpf/authpf.allow does exist, then a 458 * user must be listed if the connection is to continue, else 459 * the session terminates in the same manner as being banned. 460 */ 461 static int 462 allowed_luser(struct passwd *pw) 463 { 464 char *buf, *lbuf; 465 int matched; 466 size_t len; 467 FILE *f; 468 469 if ((f = fopen(PATH_ALLOWFILE, "r")) == NULL) { 470 if (errno == ENOENT) { 471 /* 472 * allowfile doesn't exist, thus this gateway 473 * isn't restricted to certain users... 474 */ 475 return (1); 476 } 477 478 /* 479 * luser may in fact be allowed, but we can't open 480 * the file even though it's there. probably a config 481 * problem. 482 */ 483 syslog(LOG_ERR, "cannot open allowed users file %s (%s)", 484 PATH_ALLOWFILE, strerror(errno)); 485 return (0); 486 } else { 487 /* 488 * /etc/authpf/authpf.allow exists, thus we do a linear 489 * search to see if they are allowed. 490 * also, if username "*" exists, then this is a 491 * "public" gateway, such as it is, so let 492 * everyone use it. 493 */ 494 int gl_init = 0, ngroups = NGROUPS + 1; 495 gid_t groups[NGROUPS + 1]; 496 497 lbuf = NULL; 498 matched = 0; 499 500 while ((buf = fgetln(f, &len))) { 501 502 if (buf[len - 1] == '\n') 503 buf[len - 1] = '\0'; 504 else { 505 if ((lbuf = (char *)malloc(len + 1)) == NULL) 506 err(1, NULL); 507 memcpy(lbuf, buf, len); 508 lbuf[len] = '\0'; 509 buf = lbuf; 510 } 511 512 if (buf[0] == '@') { 513 /* check login class */ 514 if (strcmp(pw->pw_class, buf + 1) == 0) 515 matched++; 516 } else if (buf[0] == '%') { 517 /* check group membership */ 518 int cnt; 519 struct group *group; 520 521 if ((group = getgrnam(buf + 1)) == NULL) { 522 syslog(LOG_ERR, 523 "invalid group '%s' in %s (%s)", 524 buf + 1, PATH_ALLOWFILE, 525 strerror(errno)); 526 return (0); 527 } 528 529 if (!gl_init) { 530 (void) getgrouplist(pw->pw_name, 531 pw->pw_gid, groups, &ngroups); 532 gl_init++; 533 } 534 535 for ( cnt = 0; cnt < ngroups; cnt++) { 536 if (group->gr_gid == groups[cnt]) { 537 matched++; 538 break; 539 } 540 } 541 } else { 542 /* check username and wildcard */ 543 matched = strcmp(pw->pw_name, buf) == 0 || 544 strcmp("*", buf) == 0; 545 } 546 547 if (lbuf != NULL) { 548 free(lbuf); 549 lbuf = NULL; 550 } 551 552 if (matched) 553 return (1); /* matched an allowed user/group */ 554 } 555 syslog(LOG_INFO, "denied access to %s: not listed in %s", 556 pw->pw_name, PATH_ALLOWFILE); 557 558 /* reuse buf */ 559 buf = "\n\nSorry, you are not allowed to use this facility!\n"; 560 fputs(buf, stdout); 561 } 562 fflush(stdout); 563 return (0); 564 } 565 566 /* 567 * check_luser checks to see if user "luser" has been banned 568 * from using us by virtue of having an file of the same name 569 * in the "luserdir" directory. 570 * 571 * If the user has been banned, we copy the contents of the file 572 * to the user's screen. (useful for telling the user what to 573 * do to get un-banned, or just to tell them they aren't 574 * going to be un-banned.) 575 */ 576 static int 577 check_luser(char *luserdir, char *luser) 578 { 579 FILE *f; 580 int n; 581 char tmp[MAXPATHLEN]; 582 583 n = snprintf(tmp, sizeof(tmp), "%s/%s", luserdir, luser); 584 if (n < 0 || (u_int)n >= sizeof(tmp)) { 585 syslog(LOG_ERR, "provided banned directory line too long (%s)", 586 luserdir); 587 return (0); 588 } 589 if ((f = fopen(tmp, "r")) == NULL) { 590 if (errno == ENOENT) { 591 /* 592 * file or dir doesn't exist, so therefore 593 * this luser isn't banned.. all is well 594 */ 595 return (1); 596 } else { 597 /* 598 * luser may in fact be banned, but we can't open the 599 * file even though it's there. probably a config 600 * problem. 601 */ 602 syslog(LOG_ERR, "cannot open banned file %s (%s)", 603 tmp, strerror(errno)); 604 return (0); 605 } 606 } else { 607 /* 608 * luser is banned - spit the file at them to 609 * tell what they can do and where they can go. 610 */ 611 syslog(LOG_INFO, "denied access to %s: %s exists", 612 luser, tmp); 613 614 /* reuse tmp */ 615 strlcpy(tmp, "\n\n-**- Sorry, you have been banned! -**-\n\n", 616 sizeof(tmp)); 617 while (fputs(tmp, stdout) != EOF && !feof(f)) { 618 if (fgets(tmp, sizeof(tmp), f) == NULL) { 619 fflush(stdout); 620 fclose(f); 621 return (0); 622 } 623 } 624 fclose(f); 625 } 626 fflush(stdout); 627 return (0); 628 } 629 630 /* 631 * Search for rulesets left by other authpf processes (either because they 632 * died ungracefully or were terminated) and remove them. 633 */ 634 static int 635 remove_stale_rulesets(void) 636 { 637 struct pfioc_ruleset prs; 638 u_int32_t nr; 639 640 memset(&prs, 0, sizeof(prs)); 641 strlcpy(prs.path, anchorname, sizeof(prs.path)); 642 if (ioctl(dev, DIOCGETRULESETS, &prs)) { 643 if (errno == EINVAL) 644 return (0); 645 else 646 return (1); 647 } 648 649 nr = prs.nr; 650 while (nr) { 651 char *s, *t; 652 pid_t pid; 653 654 prs.nr = nr - 1; 655 if (ioctl(dev, DIOCGETRULESET, &prs)) 656 return (1); 657 errno = 0; 658 if ((t = strchr(prs.name, '(')) == NULL) 659 t = prs.name; 660 else 661 t++; 662 pid = strtoul(t, &s, 10); 663 if (!prs.name[0] || errno || 664 (*s && (t == prs.name || *s != ')'))) 665 return (1); 666 if ((kill(pid, 0) && errno != EPERM) || pid == getpid()) { 667 if (recursive_ruleset_purge(anchorname, prs.name)) 668 return (1); 669 } 670 nr--; 671 } 672 return (0); 673 } 674 675 static int 676 recursive_ruleset_purge(char *an, char *rs) 677 { 678 struct pfioc_trans_e *t_e = NULL; 679 struct pfioc_trans *t = NULL; 680 struct pfioc_ruleset *prs = NULL; 681 682 /* purge rules */ 683 errno = 0; 684 if ((t = calloc(1, sizeof(struct pfioc_trans))) == NULL) 685 goto no_mem; 686 if ((t_e = calloc(2, sizeof(struct pfioc_trans_e))) == NULL) 687 goto no_mem; 688 t->size = 2; 689 t->esize = sizeof(struct pfioc_trans_e); 690 t->array = t_e; 691 t_e[0].type = PF_TRANS_RULESET; 692 snprintf(t_e[0].anchor, sizeof(t_e[0].anchor), "%s/%s", an, rs); 693 t_e[1].type = PF_TRANS_TABLE; 694 695 if ((ioctl(dev, DIOCXBEGIN, t) || 696 ioctl(dev, DIOCXCOMMIT, t)) && 697 errno != EINVAL) 698 goto cleanup; 699 700 /* purge any children */ 701 if ((prs = calloc(1, sizeof(struct pfioc_ruleset))) == NULL) 702 goto no_mem; 703 snprintf(prs->path, sizeof(prs->path), "%s/%s", an, rs); 704 if (ioctl(dev, DIOCGETRULESETS, prs)) { 705 if (errno != EINVAL) 706 goto cleanup; 707 errno = 0; 708 } else { 709 int nr = prs->nr; 710 711 while (nr) { 712 prs->nr = 0; 713 if (ioctl(dev, DIOCGETRULESET, prs)) 714 goto cleanup; 715 716 if (recursive_ruleset_purge(prs->path, prs->name)) 717 goto cleanup; 718 nr--; 719 } 720 } 721 722 no_mem: 723 if (errno == ENOMEM) 724 syslog(LOG_ERR, "calloc failed"); 725 726 cleanup: 727 free(t); 728 free(t_e); 729 free(prs); 730 return (errno); 731 } 732 733 /* 734 * Add/remove filter entries for user "luser" from ip "ipsrc" 735 */ 736 static int 737 change_filter(int add, const char *luser, const char *ipsrc) 738 { 739 char *fdpath = NULL, *userstr = NULL, *ipstr = NULL; 740 char *rsn = NULL, *fn = NULL; 741 pid_t pid; 742 gid_t gid; 743 int s; 744 745 if (add) { 746 struct stat sb; 747 char *pargv[13] = { 748 "pfctl", "-p", "/dev/pf", "-q", "-a", "anchor/ruleset", 749 "-D", "user_id=X", "-D", "user_ip=X", "-f", "file", NULL 750 }; 751 752 if (luser == NULL || !luser[0] || ipsrc == NULL || !ipsrc[0]) { 753 syslog(LOG_ERR, "invalid luser/ipsrc"); 754 goto error; 755 } 756 757 if (asprintf(&rsn, "%s/%s", anchorname, rulesetname) == -1) 758 goto no_mem; 759 if (asprintf(&fdpath, "/dev/fd/%d", dev) == -1) 760 goto no_mem; 761 if (asprintf(&ipstr, "user_ip=%s", ipsrc) == -1) 762 goto no_mem; 763 if (asprintf(&userstr, "user_id=%s", luser) == -1) 764 goto no_mem; 765 if (asprintf(&fn, "%s/%s/authpf.rules", 766 PATH_USER_DIR, luser) == -1) 767 goto no_mem; 768 if (stat(fn, &sb) == -1) { 769 free(fn); 770 if ((fn = strdup(PATH_PFRULES)) == NULL) 771 goto no_mem; 772 } 773 pargv[2] = fdpath; 774 pargv[5] = rsn; 775 pargv[7] = userstr; 776 if (user_ip) { 777 pargv[9] = ipstr; 778 pargv[11] = fn; 779 } else { 780 pargv[8] = "-f"; 781 pargv[9] = fn; 782 pargv[10] = NULL; 783 } 784 785 switch (pid = fork()) { 786 case -1: 787 syslog(LOG_ERR, "fork failed"); 788 goto error; 789 case 0: 790 /* revoke group privs before exec */ 791 gid = getgid(); 792 if (setregid(gid, gid) == -1) { 793 err(1, "setregid"); 794 } 795 execvp(PATH_PFCTL, pargv); 796 warn("exec of %s failed", PATH_PFCTL); 797 _exit(1); 798 } 799 800 /* parent */ 801 waitpid(pid, &s, 0); 802 if (s != 0) { 803 syslog(LOG_ERR, "pfctl exited abnormally"); 804 goto error; 805 } 806 807 gettimeofday(&Tstart, NULL); 808 syslog(LOG_INFO, "allowing %s, user %s", ipsrc, luser); 809 } else { 810 remove_stale_rulesets(); 811 812 gettimeofday(&Tend, NULL); 813 syslog(LOG_INFO, "removed %s, user %s - duration %ld seconds", 814 ipsrc, luser, Tend.tv_sec - Tstart.tv_sec); 815 } 816 return (0); 817 no_mem: 818 syslog(LOG_ERR, "malloc failed"); 819 error: 820 free(fdpath); 821 free(rsn); 822 free(userstr); 823 free(ipstr); 824 free(fn); 825 return (-1); 826 } 827 828 /* 829 * Add/remove this IP from the "authpf_users" table. 830 */ 831 static int 832 change_table(int add, const char *ipsrc) 833 { 834 struct pfioc_table io; 835 struct pfr_addr addr; 836 837 bzero(&io, sizeof(io)); 838 strlcpy(io.pfrio_table.pfrt_name, tablename, 839 sizeof(io.pfrio_table.pfrt_name)); 840 io.pfrio_buffer = &addr; 841 io.pfrio_esize = sizeof(addr); 842 io.pfrio_size = 1; 843 844 bzero(&addr, sizeof(addr)); 845 if (ipsrc == NULL || !ipsrc[0]) 846 return (-1); 847 if (inet_pton(AF_INET, ipsrc, &addr.pfra_ip4addr) == 1) { 848 addr.pfra_af = AF_INET; 849 addr.pfra_net = 32; 850 } else if (inet_pton(AF_INET6, ipsrc, &addr.pfra_ip6addr) == 1) { 851 addr.pfra_af = AF_INET6; 852 addr.pfra_net = 128; 853 } else { 854 syslog(LOG_ERR, "invalid ipsrc"); 855 return (-1); 856 } 857 858 if (ioctl(dev, add ? DIOCRADDADDRS : DIOCRDELADDRS, &io) && 859 errno != ESRCH) { 860 syslog(LOG_ERR, "cannot %s %s from table %s: %s", 861 add ? "add" : "remove", ipsrc, tablename, 862 strerror(errno)); 863 return (-1); 864 } 865 return (0); 866 } 867 868 /* 869 * This is to kill off states that would otherwise be left behind stateful 870 * rules. This means we don't need to allow in more traffic than we really 871 * want to, since we don't have to worry about any luser sessions lasting 872 * longer than their ssh session. This function is based on 873 * pfctl_kill_states from pfctl. 874 */ 875 static void 876 authpf_kill_states(void) 877 { 878 struct pfioc_state_kill psk; 879 struct pf_addr target; 880 881 memset(&psk, 0, sizeof(psk)); 882 memset(&target, 0, sizeof(target)); 883 884 if (inet_pton(AF_INET, ipsrc, &target.v4) == 1) 885 psk.psk_af = AF_INET; 886 else if (inet_pton(AF_INET6, ipsrc, &target.v6) == 1) 887 psk.psk_af = AF_INET6; 888 else { 889 syslog(LOG_ERR, "inet_pton(%s) failed", ipsrc); 890 return; 891 } 892 893 /* Kill all states from ipsrc */ 894 memcpy(&psk.psk_src.addr.v.a.addr, &target, 895 sizeof(psk.psk_src.addr.v.a.addr)); 896 memset(&psk.psk_src.addr.v.a.mask, 0xff, 897 sizeof(psk.psk_src.addr.v.a.mask)); 898 if (ioctl(dev, DIOCKILLSTATES, &psk)) 899 syslog(LOG_ERR, "DIOCKILLSTATES failed (%m)"); 900 901 /* Kill all states to ipsrc */ 902 memset(&psk.psk_src, 0, sizeof(psk.psk_src)); 903 memcpy(&psk.psk_dst.addr.v.a.addr, &target, 904 sizeof(psk.psk_dst.addr.v.a.addr)); 905 memset(&psk.psk_dst.addr.v.a.mask, 0xff, 906 sizeof(psk.psk_dst.addr.v.a.mask)); 907 if (ioctl(dev, DIOCKILLSTATES, &psk)) 908 syslog(LOG_ERR, "DIOCKILLSTATES failed (%m)"); 909 } 910 911 /* signal handler that makes us go away properly */ 912 static void 913 need_death(int signo) 914 { 915 want_death = 1; 916 } 917 918 /* 919 * function that removes our stuff when we go away. 920 */ 921 static __dead void 922 do_death(int active) 923 { 924 int ret = 0; 925 926 if (active) { 927 change_filter(0, luser, ipsrc); 928 if (user_ip) { 929 change_table(0, ipsrc); 930 authpf_kill_states(); 931 } 932 } 933 if (pidfile[0] && pidfd != -1) 934 if (unlink(pidfile) == -1) 935 syslog(LOG_ERR, "cannot unlink %s (%m)", pidfile); 936 exit(ret); 937 } 938