1 /* $OpenBSD: authpf.c,v 1.128 2019/06/28 13:32:47 deraadt 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/ioctl.h> 21 #include <sys/socket.h> 22 #include <sys/stat.h> 23 #include <sys/wait.h> 24 25 #include <netinet/in.h> 26 #include <arpa/inet.h> 27 #include <net/if.h> 28 #include <net/pfvar.h> 29 30 #include <err.h> 31 #include <errno.h> 32 #include <fcntl.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 <time.h> 42 #include <unistd.h> 43 44 #include "pathnames.h" 45 46 static int read_config(FILE *); 47 static void print_message(char *); 48 static int allowed_luser(struct passwd *); 49 static int check_luser(char *, char *); 50 static int remove_stale_rulesets(void); 51 static int recursive_ruleset_purge(char *, char *); 52 static int change_filter(int, const char *, const char *); 53 static int change_table(int, const char *); 54 static void authpf_kill_states(void); 55 56 int dev; /* pf device */ 57 char anchorname[PF_ANCHOR_NAME_SIZE] = "authpf"; 58 char rulesetname[PATH_MAX - PF_ANCHOR_NAME_SIZE - 2]; 59 char tablename[PF_TABLE_NAME_SIZE] = "authpf_users"; 60 int user_ip = 1; /* controls whether $user_ip is set */ 61 62 FILE *pidfp; 63 int pidfd = -1; 64 char luser[LOGIN_NAME_MAX]; /* username */ 65 char ipsrc[256]; /* ip as a string */ 66 char pidfile[PATH_MAX]; /* we save pid in this file. */ 67 68 struct timespec Tstart, Tend; /* start and end times of session */ 69 70 volatile sig_atomic_t want_death; 71 static void need_death(int signo); 72 static __dead void do_death(int); 73 extern char *__progname; /* program name */ 74 75 /* 76 * User shell for authenticating gateways. Sole purpose is to allow 77 * a user to ssh to a gateway, and have the gateway modify packet 78 * filters to allow access, then remove access when the user finishes 79 * up. Meant to be used only from ssh(1) connections. 80 */ 81 int 82 main(int argc, char *argv[]) 83 { 84 int lockcnt = 0, n; 85 FILE *config; 86 struct in6_addr ina; 87 struct passwd *pw; 88 char *cp; 89 gid_t gid; 90 uid_t uid; 91 char *shell; 92 login_cap_t *lc; 93 94 if (strcmp(__progname, "-authpf-noip") == 0) 95 user_ip = 0; 96 97 config = fopen(PATH_CONFFILE, "r"); 98 if (config == NULL) { 99 syslog(LOG_ERR, "cannot open %s (%m)", PATH_CONFFILE); 100 exit(1); 101 } 102 103 if ((cp = getenv("SSH_TTY")) == NULL) { 104 syslog(LOG_ERR, "non-interactive session connection for authpf"); 105 exit(1); 106 } 107 108 if ((cp = getenv("SSH_CLIENT")) == NULL) { 109 syslog(LOG_ERR, "cannot determine connection source"); 110 exit(1); 111 } 112 113 if (strlcpy(ipsrc, cp, sizeof(ipsrc)) >= sizeof(ipsrc)) { 114 syslog(LOG_ERR, "SSH_CLIENT variable too long"); 115 exit(1); 116 } 117 cp = strchr(ipsrc, ' '); 118 if (!cp) { 119 syslog(LOG_ERR, "corrupt SSH_CLIENT variable %s", ipsrc); 120 exit(1); 121 } 122 *cp = '\0'; 123 if (inet_pton(AF_INET, ipsrc, &ina) != 1 && 124 inet_pton(AF_INET6, ipsrc, &ina) != 1) { 125 syslog(LOG_ERR, 126 "cannot determine IP from SSH_CLIENT %s", ipsrc); 127 exit(1); 128 } 129 /* open the pf device */ 130 dev = open(PATH_DEVFILE, O_RDWR); 131 if (dev == -1) { 132 syslog(LOG_ERR, "cannot open packet filter device (%m)"); 133 goto die; 134 } 135 136 uid = getuid(); 137 pw = getpwuid(uid); 138 if (pw == NULL) { 139 syslog(LOG_ERR, "cannot find user for uid %u", uid); 140 goto die; 141 } 142 143 if ((lc = login_getclass(pw->pw_class)) != NULL) 144 shell = login_getcapstr(lc, "shell", pw->pw_shell, 145 pw->pw_shell); 146 else 147 shell = pw->pw_shell; 148 149 login_close(lc); 150 151 if (strcmp(shell, PATH_AUTHPF_SHELL) && 152 strcmp(shell, PATH_AUTHPF_SHELL_NOIP)) { 153 syslog(LOG_ERR, "wrong shell for user %s, uid %u", 154 pw->pw_name, pw->pw_uid); 155 if (shell != pw->pw_shell) 156 free(shell); 157 goto die; 158 } 159 160 if (shell != pw->pw_shell) 161 free(shell); 162 163 /* 164 * Paranoia, but this data _does_ come from outside authpf, and 165 * truncation would be bad. 166 */ 167 if (strlcpy(luser, pw->pw_name, sizeof(luser)) >= sizeof(luser)) { 168 syslog(LOG_ERR, "username too long: %s", pw->pw_name); 169 goto die; 170 } 171 172 if ((n = snprintf(rulesetname, sizeof(rulesetname), "%s(%ld)", 173 luser, (long)getpid())) < 0 || (u_int)n >= sizeof(rulesetname)) { 174 syslog(LOG_INFO, "%s(%ld) too large, ruleset name will be %ld", 175 luser, (long)getpid(), (long)getpid()); 176 if ((n = snprintf(rulesetname, sizeof(rulesetname), "%ld", 177 (long)getpid())) < 0 || (u_int)n >= sizeof(rulesetname)) { 178 syslog(LOG_ERR, "pid too large for ruleset name"); 179 goto die; 180 } 181 } 182 183 184 /* Make our entry in /var/authpf as ipaddr or username */ 185 n = snprintf(pidfile, sizeof(pidfile), "%s/%s", 186 PATH_PIDFILE, user_ip ? ipsrc : luser); 187 if (n < 0 || (u_int)n >= sizeof(pidfile)) { 188 syslog(LOG_ERR, "path to pidfile too long"); 189 goto die; 190 } 191 192 signal(SIGTERM, need_death); 193 signal(SIGINT, need_death); 194 signal(SIGALRM, need_death); 195 signal(SIGPIPE, need_death); 196 signal(SIGHUP, need_death); 197 signal(SIGQUIT, need_death); 198 signal(SIGTSTP, need_death); 199 200 /* 201 * If someone else is already using this ip, then this person 202 * wants to switch users - so kill the old process and exit 203 * as well. 204 * 205 * Note, we could print a message and tell them to log out, but the 206 * usual case of this is that someone has left themselves logged in, 207 * with the authenticated connection iconized and someone else walks 208 * up to use and automatically logs in before using. If this just 209 * gets rid of the old one silently, the new user never knows they 210 * could have used someone else's old authentication. If we 211 * tell them to log out before switching users it is an invitation 212 * for abuse. 213 */ 214 215 do { 216 int save_errno, otherpid = -1; 217 char otherluser[LOGIN_NAME_MAX]; 218 219 if ((pidfd = open(pidfile, O_RDWR|O_CREAT, 0644)) == -1 || 220 (pidfp = fdopen(pidfd, "r+")) == NULL) { 221 if (pidfd != -1) 222 close(pidfd); 223 syslog(LOG_ERR, "cannot open or create %s: %s", pidfile, 224 strerror(errno)); 225 goto die; 226 } 227 228 if (flock(fileno(pidfp), LOCK_EX|LOCK_NB) == 0) 229 break; 230 save_errno = errno; 231 232 /* Mark our pid, and username to our file. */ 233 234 rewind(pidfp); 235 /* 31 == MAXLOGNAME - 1 */ 236 if (fscanf(pidfp, "%d\n%31s\n", &otherpid, otherluser) != 2) 237 otherpid = -1; 238 syslog(LOG_DEBUG, "tried to lock %s, in use by pid %d: %s", 239 pidfile, otherpid, strerror(save_errno)); 240 241 if (otherpid > 0) { 242 syslog(LOG_INFO, 243 "killing prior auth (pid %d) of %s by user %s", 244 otherpid, ipsrc, otherluser); 245 if (kill((pid_t) otherpid, SIGTERM) == -1) { 246 syslog(LOG_INFO, 247 "could not kill process %d: (%m)", 248 otherpid); 249 } 250 } 251 252 /* 253 * We try to kill the previous process and acquire the lock 254 * for 10 seconds, trying once a second. if we can't after 255 * 10 attempts we log an error and give up. 256 */ 257 if (want_death || ++lockcnt > 10) { 258 if (!want_death) 259 syslog(LOG_ERR, "cannot kill previous authpf (pid %d)", 260 otherpid); 261 fclose(pidfp); 262 pidfp = NULL; 263 pidfd = -1; 264 goto dogdeath; 265 } 266 sleep(1); 267 268 /* re-open, and try again. The previous authpf process 269 * we killed above should unlink the file and release 270 * it's lock, giving us a chance to get it now 271 */ 272 fclose(pidfp); 273 pidfp = NULL; 274 pidfd = -1; 275 } while (1); 276 277 /* whack the group list */ 278 gid = getegid(); 279 if (setgroups(1, &gid) == -1) { 280 syslog(LOG_INFO, "setgroups: %s", strerror(errno)); 281 do_death(0); 282 } 283 284 /* revoke privs */ 285 uid = getuid(); 286 if (setresuid(uid, uid, uid) == -1) { 287 syslog(LOG_INFO, "setresuid: %s", strerror(errno)); 288 do_death(0); 289 } 290 openlog("authpf", LOG_PID | LOG_NDELAY, LOG_DAEMON); 291 292 if (!check_luser(PATH_BAN_DIR, luser) || !allowed_luser(pw)) { 293 syslog(LOG_INFO, "user %s prohibited", luser); 294 do_death(0); 295 } 296 297 if (read_config(config)) { 298 syslog(LOG_ERR, "invalid config file %s", PATH_CONFFILE); 299 do_death(0); 300 } 301 302 if (remove_stale_rulesets()) { 303 syslog(LOG_INFO, "error removing stale rulesets"); 304 do_death(0); 305 } 306 307 /* We appear to be making headway, so actually mark our pid */ 308 rewind(pidfp); 309 fprintf(pidfp, "%ld\n%s\n", (long)getpid(), luser); 310 fflush(pidfp); 311 (void) ftruncate(fileno(pidfp), ftello(pidfp)); 312 313 if (change_filter(1, luser, ipsrc) == -1) { 314 printf("Unable to modify filters\r\n"); 315 do_death(0); 316 } 317 if (user_ip && change_table(1, ipsrc) == -1) { 318 printf("Unable to modify table\r\n"); 319 change_filter(0, luser, ipsrc); 320 do_death(0); 321 } 322 323 while (1) { 324 struct stat sb; 325 char *path_message; 326 printf("\r\nHello %s. ", luser); 327 printf("You are authenticated from host \"%s\"\r\n", ipsrc); 328 setproctitle("%s@%s", luser, ipsrc); 329 if (asprintf(&path_message, "%s/%s/authpf.message", 330 PATH_USER_DIR, luser) == -1) 331 do_death(1); 332 if (stat(path_message, &sb) == -1 || ! S_ISREG(sb.st_mode)) { 333 free(path_message); 334 if ((path_message = strdup(PATH_MESSAGE)) == NULL) 335 do_death(1); 336 } 337 print_message(path_message); 338 while (1) { 339 sleep(10); 340 if (want_death) 341 do_death(1); 342 } 343 } 344 345 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_MAX + 1; 495 gid_t groups[NGROUPS_MAX + 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 = 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 fclose(f); 527 return (0); 528 } 529 530 if (!gl_init) { 531 (void) getgrouplist(pw->pw_name, 532 pw->pw_gid, groups, &ngroups); 533 gl_init++; 534 } 535 536 for ( cnt = 0; cnt < ngroups; cnt++) { 537 if (group->gr_gid == groups[cnt]) { 538 matched++; 539 break; 540 } 541 } 542 } else { 543 /* check username and wildcard */ 544 matched = strcmp(pw->pw_name, buf) == 0 || 545 strcmp("*", buf) == 0; 546 } 547 548 free(lbuf); 549 lbuf = NULL; 550 551 if (matched) { 552 fclose(f); 553 return (1); /* matched an allowed user/group */ 554 } 555 } 556 syslog(LOG_INFO, "denied access to %s: not listed in %s", 557 pw->pw_name, PATH_ALLOWFILE); 558 559 /* reuse buf */ 560 buf = "\n\nSorry, you are not allowed to use this facility!\n"; 561 fputs(buf, stdout); 562 } 563 fflush(stdout); 564 fclose(f); 565 return (0); 566 } 567 568 /* 569 * check_luser checks to see if user "luser" has been banned 570 * from using us by virtue of having an file of the same name 571 * in the "luserdir" directory. 572 * 573 * If the user has been banned, we copy the contents of the file 574 * to the user's screen. (useful for telling the user what to 575 * do to get un-banned, or just to tell them they aren't 576 * going to be un-banned.) 577 */ 578 static int 579 check_luser(char *luserdir, char *luser) 580 { 581 FILE *f; 582 int n; 583 char tmp[PATH_MAX]; 584 585 n = snprintf(tmp, sizeof(tmp), "%s/%s", luserdir, luser); 586 if (n < 0 || (u_int)n >= sizeof(tmp)) { 587 syslog(LOG_ERR, "provided banned directory line too long (%s)", 588 luserdir); 589 return (0); 590 } 591 if ((f = fopen(tmp, "r")) == NULL) { 592 if (errno == ENOENT) { 593 /* 594 * file or dir doesn't exist, so therefore 595 * this luser isn't banned.. all is well 596 */ 597 return (1); 598 } else { 599 /* 600 * luser may in fact be banned, but we can't open the 601 * file even though it's there. probably a config 602 * problem. 603 */ 604 syslog(LOG_ERR, "cannot open banned file %s (%s)", 605 tmp, strerror(errno)); 606 return (0); 607 } 608 } else { 609 /* 610 * luser is banned - spit the file at them to 611 * tell what they can do and where they can go. 612 */ 613 syslog(LOG_INFO, "denied access to %s: %s exists", 614 luser, tmp); 615 616 /* reuse tmp */ 617 strlcpy(tmp, "\n\n-**- Sorry, you have been banned! -**-\n\n", 618 sizeof(tmp)); 619 while (fputs(tmp, stdout) != EOF && !feof(f)) { 620 if (fgets(tmp, sizeof(tmp), f) == NULL) { 621 fflush(stdout); 622 fclose(f); 623 return (0); 624 } 625 } 626 fclose(f); 627 } 628 fflush(stdout); 629 return (0); 630 } 631 632 /* 633 * Search for rulesets left by other authpf processes (either because they 634 * died ungracefully or were terminated) and remove them. 635 */ 636 static int 637 remove_stale_rulesets(void) 638 { 639 struct pfioc_ruleset prs; 640 u_int32_t nr; 641 642 memset(&prs, 0, sizeof(prs)); 643 strlcpy(prs.path, anchorname, sizeof(prs.path)); 644 if (ioctl(dev, DIOCGETRULESETS, &prs) == -1) { 645 if (errno == EINVAL) 646 return (0); 647 else 648 return (1); 649 } 650 651 nr = prs.nr; 652 while (nr) { 653 char *s, *t; 654 pid_t pid; 655 656 prs.nr = nr - 1; 657 if (ioctl(dev, DIOCGETRULESET, &prs) == -1) 658 return (1); 659 errno = 0; 660 if ((t = strchr(prs.name, '(')) == NULL) 661 t = prs.name; 662 else 663 t++; 664 pid = strtoul(t, &s, 10); 665 if (!prs.name[0] || errno || 666 (*s && (t == prs.name || *s != ')'))) 667 return (1); 668 if ((kill(pid, 0) && errno != EPERM) || pid == getpid()) { 669 if (recursive_ruleset_purge(anchorname, prs.name)) 670 return (1); 671 } 672 nr--; 673 } 674 return (0); 675 } 676 677 static int 678 recursive_ruleset_purge(char *an, char *rs) 679 { 680 struct pfioc_trans_e *t_e = NULL; 681 struct pfioc_trans *t = NULL; 682 struct pfioc_ruleset *prs = NULL; 683 684 /* purge rules */ 685 errno = 0; 686 if ((t = calloc(1, sizeof(struct pfioc_trans))) == NULL) 687 goto no_mem; 688 if ((t_e = calloc(2, sizeof(struct pfioc_trans_e))) == NULL) 689 goto no_mem; 690 t->size = 2; 691 t->esize = sizeof(struct pfioc_trans_e); 692 t->array = t_e; 693 t_e[0].type = PF_TRANS_RULESET; 694 snprintf(t_e[0].anchor, sizeof(t_e[0].anchor), "%s/%s", an, rs); 695 t_e[1].type = PF_TRANS_TABLE; 696 697 if ((ioctl(dev, DIOCXBEGIN, t) == -1|| 698 ioctl(dev, DIOCXCOMMIT, t) == -1) && 699 errno != EINVAL) 700 goto cleanup; 701 702 /* purge any children */ 703 if ((prs = calloc(1, sizeof(struct pfioc_ruleset))) == NULL) 704 goto no_mem; 705 snprintf(prs->path, sizeof(prs->path), "%s/%s", an, rs); 706 if (ioctl(dev, DIOCGETRULESETS, prs) == -1) { 707 if (errno != EINVAL) 708 goto cleanup; 709 errno = 0; 710 } else { 711 int nr = prs->nr; 712 713 while (nr) { 714 prs->nr = 0; 715 if (ioctl(dev, DIOCGETRULESET, prs) == -1) 716 goto cleanup; 717 718 if (recursive_ruleset_purge(prs->path, prs->name)) 719 goto cleanup; 720 nr--; 721 } 722 } 723 724 no_mem: 725 if (errno == ENOMEM) 726 syslog(LOG_ERR, "calloc failed"); 727 728 cleanup: 729 free(t); 730 free(t_e); 731 free(prs); 732 return (errno); 733 } 734 735 /* 736 * Add/remove filter entries for user "luser" from ip "ipsrc" 737 */ 738 static int 739 change_filter(int add, const char *luser, const char *ipsrc) 740 { 741 char *fdpath = NULL, *userstr = NULL, *ipstr = NULL; 742 char *rsn = NULL, *fn = NULL; 743 pid_t pid; 744 gid_t gid; 745 int s; 746 747 if (add) { 748 struct stat sb; 749 struct group *grent; 750 char *pargv[13] = { 751 "pfctl", "-p", "/dev/pf", "-q", "-a", "anchor/ruleset", 752 "-D", "user_id=X", "-D", "user_ip=X", "-f", "file", NULL 753 }; 754 755 if((grent = getgrgid(getgid())) == NULL) { 756 syslog(LOG_ERR, "Group not found user %s, gid %d", 757 luser, getgid()); 758 goto error; 759 } 760 761 if (luser == NULL || !luser[0] || ipsrc == NULL || !ipsrc[0]) { 762 syslog(LOG_ERR, "invalid luser/ipsrc"); 763 goto error; 764 } 765 766 if (asprintf(&rsn, "%s/%s", anchorname, rulesetname) == -1) 767 goto no_mem; 768 if (asprintf(&fdpath, "/dev/fd/%d", dev) == -1) 769 goto no_mem; 770 if (asprintf(&ipstr, "user_ip=%s", ipsrc) == -1) 771 goto no_mem; 772 if (asprintf(&userstr, "user_id=%s", luser) == -1) 773 goto no_mem; 774 if (asprintf(&fn, "%s/%s/authpf.rules", 775 PATH_USER_DIR, luser) == -1) 776 goto no_mem; 777 if (stat(fn, &sb) == -1) { 778 free(fn); 779 if(asprintf(&fn, "%s/%s/authpf.rules", PATH_GROUP_DIR, 780 grent->gr_name) == -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 } 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 (setresgid(gid, 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 clock_gettime(CLOCK_MONOTONIC, &Tstart); 823 syslog(LOG_INFO, "allowing %s, user %s", ipsrc, luser); 824 } else { 825 remove_stale_rulesets(); 826 827 clock_gettime(CLOCK_MONOTONIC, &Tend); 828 syslog(LOG_INFO, "removed %s, user %s - duration %d seconds", 829 ipsrc, luser, (int)(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 *ipsrc) 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 (ipsrc == NULL || !ipsrc[0]) 861 return (-1); 862 if (inet_pton(AF_INET, ipsrc, &addr.pfra_ip4addr) == 1) { 863 addr.pfra_af = AF_INET; 864 addr.pfra_net = 32; 865 } else if (inet_pton(AF_INET6, ipsrc, &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) == -1 && 874 errno != ESRCH) { 875 syslog(LOG_ERR, "cannot %s %s from table %s: %s", 876 add ? "add" : "remove", ipsrc, 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 pfioc_state_kill psk; 894 struct pf_addr target; 895 896 memset(&psk, 0, sizeof(psk)); 897 memset(&target, 0, sizeof(target)); 898 899 if (inet_pton(AF_INET, ipsrc, &target.v4) == 1) 900 psk.psk_af = AF_INET; 901 else if (inet_pton(AF_INET6, ipsrc, &target.v6) == 1) 902 psk.psk_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(&psk.psk_src.addr.v.a.addr, &target, 910 sizeof(psk.psk_src.addr.v.a.addr)); 911 memset(&psk.psk_src.addr.v.a.mask, 0xff, 912 sizeof(psk.psk_src.addr.v.a.mask)); 913 if (ioctl(dev, DIOCKILLSTATES, &psk) == -1) 914 syslog(LOG_ERR, "DIOCKILLSTATES failed (%m)"); 915 916 /* Kill all states to ipsrc */ 917 memset(&psk.psk_src, 0, sizeof(psk.psk_src)); 918 memcpy(&psk.psk_dst.addr.v.a.addr, &target, 919 sizeof(psk.psk_dst.addr.v.a.addr)); 920 memset(&psk.psk_dst.addr.v.a.mask, 0xff, 921 sizeof(psk.psk_dst.addr.v.a.mask)); 922 if (ioctl(dev, DIOCKILLSTATES, &psk) == -1) 923 syslog(LOG_ERR, "DIOCKILLSTATES failed (%m)"); 924 } 925 926 /* signal handler that makes us go away properly */ 927 static void 928 need_death(int signo) 929 { 930 want_death = 1; 931 } 932 933 /* 934 * function that removes our stuff when we go away. 935 */ 936 static __dead void 937 do_death(int active) 938 { 939 int ret = 0; 940 941 if (active) { 942 change_filter(0, luser, ipsrc); 943 if (user_ip) { 944 change_table(0, ipsrc); 945 authpf_kill_states(); 946 } 947 } 948 if (pidfile[0] && pidfd != -1) 949 if (unlink(pidfile) == -1) 950 syslog(LOG_ERR, "cannot unlink %s (%m)", pidfile); 951 exit(ret); 952 } 953