1 /*- 2 * SPDX-License-Identifier: BSD-3-Clause 3 * 4 * Copyright (c) 1983, 1993, 1994 5 * The Regents of the University of California. All rights reserved. 6 * 7 * 8 * Redistribution and use in source and binary forms, with or without 9 * modification, are permitted provided that the following conditions 10 * are met: 11 * 1. Redistributions of source code must retain the above copyright 12 * notice, this list of conditions and the following disclaimer. 13 * 2. Redistributions in binary form must reproduce the above copyright 14 * notice, this list of conditions and the following disclaimer in the 15 * documentation and/or other materials provided with the distribution. 16 * 3. Neither the name of the University nor the names of its contributors 17 * may be used to endorse or promote products derived from this software 18 * without specific prior written permission. 19 * 20 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 21 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 22 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 23 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 24 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 25 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 26 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 27 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 28 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 29 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 30 * SUCH DAMAGE. 31 */ 32 33 #ifndef lint 34 static const char copyright[] = 35 "@(#) Copyright (c) 1983, 1993, 1994\n\ 36 The Regents of the University of California. All rights reserved.\n"; 37 #endif /* not lint */ 38 39 #if 0 40 #ifndef lint 41 static char sccsid[] = "@(#)lpd.c 8.7 (Berkeley) 5/10/95"; 42 #endif /* not lint */ 43 #endif 44 45 #include "lp.cdefs.h" /* A cross-platform version of <sys/cdefs.h> */ 46 __FBSDID("$FreeBSD$"); 47 48 /* 49 * lpd -- line printer daemon. 50 * 51 * Listen for a connection and perform the requested operation. 52 * Operations are: 53 * \1printer\n 54 * check the queue for jobs and print any found. 55 * \2printer\n 56 * receive a job from another machine and queue it. 57 * \3printer [users ...] [jobs ...]\n 58 * return the current state of the queue (short form). 59 * \4printer [users ...] [jobs ...]\n 60 * return the current state of the queue (long form). 61 * \5printer person [users ...] [jobs ...]\n 62 * remove jobs from the queue. 63 * 64 * Strategy to maintain protected spooling area: 65 * 1. Spooling area is writable only by daemon and spooling group 66 * 2. lpr runs setuid root and setgrp spooling group; it uses 67 * root to access any file it wants (verifying things before 68 * with an access call) and group id to know how it should 69 * set up ownership of files in the spooling area. 70 * 3. Files in spooling area are owned by root, group spooling 71 * group, with mode 660. 72 * 4. lpd, lpq and lprm run setuid daemon and setgrp spooling group to 73 * access files and printer. Users can't get to anything 74 * w/o help of lpq and lprm programs. 75 */ 76 77 #include <sys/param.h> 78 #include <sys/wait.h> 79 #include <sys/types.h> 80 #include <sys/socket.h> 81 #include <sys/un.h> 82 #include <sys/stat.h> 83 #include <sys/file.h> 84 #include <netinet/in.h> 85 #include <arpa/inet.h> 86 87 #include <netdb.h> 88 #include <unistd.h> 89 #include <syslog.h> 90 #include <signal.h> 91 #include <err.h> 92 #include <errno.h> 93 #include <fcntl.h> 94 #include <dirent.h> 95 #include <stdio.h> 96 #include <stdlib.h> 97 #include <string.h> 98 #include <sysexits.h> 99 #include <ctype.h> 100 #include "lp.h" 101 #include "lp.local.h" 102 #include "pathnames.h" 103 #include "extern.h" 104 105 int lflag; /* log requests flag */ 106 int sflag; /* no incoming port flag */ 107 int from_remote; /* from remote socket */ 108 109 int main(int argc, char **_argv); 110 static void reapchild(int _signo); 111 static void mcleanup(int _signo); 112 static void doit(void); 113 static void startup(void); 114 static void chkhost(struct sockaddr *_f, int _ch_opts); 115 static int ckqueue(struct printer *_pp); 116 static void fhosterr(int _ch_opts, char *_sysmsg, char *_usermsg); 117 static int *socksetup(int _af, int _debuglvl); 118 static void usage(void); 119 120 /* XXX from libc/net/rcmd.c */ 121 extern int __ivaliduser_sa(FILE *, struct sockaddr *, socklen_t, 122 const char *, const char *); 123 124 uid_t uid, euid; 125 126 #define LPD_NOPORTCHK 0001 /* skip reserved-port check */ 127 #define LPD_LOGCONNERR 0002 /* (sys)log connection errors */ 128 #define LPD_ADDFROMLINE 0004 /* just used for fhosterr() */ 129 130 int 131 main(int argc, char **argv) 132 { 133 int ch_options, errs, f, funix, *finet, i, lfd, socket_debug; 134 fd_set defreadfds; 135 struct sockaddr_un un, fromunix; 136 struct sockaddr_storage frominet; 137 socklen_t fromlen; 138 sigset_t omask, nmask; 139 struct servent *sp, serv; 140 int inet_flag = 0, inet6_flag = 0; 141 142 euid = geteuid(); /* these shouldn't be different */ 143 uid = getuid(); 144 145 ch_options = 0; 146 socket_debug = 0; 147 gethostname(local_host, sizeof(local_host)); 148 149 progname = "lpd"; 150 151 if (euid != 0) 152 errx(EX_NOPERM,"must run as root"); 153 154 errs = 0; 155 while ((i = getopt(argc, argv, "cdlpswW46")) != -1) 156 switch (i) { 157 case 'c': 158 /* log all kinds of connection-errors to syslog */ 159 ch_options |= LPD_LOGCONNERR; 160 break; 161 case 'd': 162 socket_debug++; 163 break; 164 case 'l': 165 lflag++; 166 break; 167 case 'p': /* letter initially used for -s */ 168 /* 169 * This will probably be removed with 5.0-release. 170 */ 171 /* FALLTHROUGH */ 172 case 's': /* secure (no inet) */ 173 sflag++; 174 break; 175 case 'w': /* netbsd uses -w for maxwait */ 176 /* 177 * This will be removed after the release of 4.4, as 178 * it conflicts with -w in netbsd's lpd. For now it 179 * is just a warning, so we won't suddenly break lpd 180 * for anyone who is currently using the option. 181 */ 182 syslog(LOG_WARNING, 183 "NOTE: the -w option has been renamed -W"); 184 syslog(LOG_WARNING, 185 "NOTE: please change your lpd config to use -W"); 186 /* FALLTHROUGH */ 187 case 'W': 188 /* allow connections coming from a non-reserved port */ 189 /* (done by some lpr-implementations for MS-Windows) */ 190 ch_options |= LPD_NOPORTCHK; 191 break; 192 case '4': 193 family = PF_INET; 194 inet_flag++; 195 break; 196 case '6': 197 #ifdef INET6 198 family = PF_INET6; 199 inet6_flag++; 200 #else 201 errx(EX_USAGE, "lpd compiled sans INET6 (IPv6 support)"); 202 #endif 203 break; 204 /* 205 * The following options are not in FreeBSD (yet?), but are 206 * listed here to "reserve" them, because the option-letters 207 * are used by either NetBSD or OpenBSD (as of July 2001). 208 */ 209 case 'b': /* set bind-addr */ 210 case 'n': /* set max num of children */ 211 case 'r': /* allow 'of' for remote ptrs */ 212 /* ...[not needed in freebsd] */ 213 /* FALLTHROUGH */ 214 default: 215 errs++; 216 } 217 if (inet_flag && inet6_flag) 218 family = PF_UNSPEC; 219 argc -= optind; 220 argv += optind; 221 if (errs) 222 usage(); 223 224 if (argc == 1) { 225 if ((i = atoi(argv[0])) == 0) 226 usage(); 227 if (i < 0 || i > USHRT_MAX) 228 errx(EX_USAGE, "port # %d is invalid", i); 229 230 serv.s_port = htons(i); 231 sp = &serv; 232 argc--; 233 } else { 234 sp = getservbyname("printer", "tcp"); 235 if (sp == NULL) 236 errx(EX_OSFILE, "printer/tcp: unknown service"); 237 } 238 239 if (argc != 0) 240 usage(); 241 242 /* 243 * We run chkprintcap right away to catch any errors and blat them 244 * to stderr while we still have it open, rather than sending them 245 * to syslog and leaving the user wondering why lpd started and 246 * then stopped. There should probably be a command-line flag to 247 * ignore errors from chkprintcap. 248 */ 249 { 250 pid_t pid; 251 int status; 252 pid = fork(); 253 if (pid < 0) { 254 err(EX_OSERR, "cannot fork"); 255 } else if (pid == 0) { /* child */ 256 execl(_PATH_CHKPRINTCAP, _PATH_CHKPRINTCAP, (char *)0); 257 err(EX_OSERR, "cannot execute %s", _PATH_CHKPRINTCAP); 258 } 259 if (waitpid(pid, &status, 0) < 0) { 260 err(EX_OSERR, "cannot wait"); 261 } 262 if (WIFEXITED(status) && WEXITSTATUS(status) != 0) 263 errx(EX_OSFILE, "%d errors in printcap file, exiting", 264 WEXITSTATUS(status)); 265 } 266 267 #ifndef DEBUG 268 /* 269 * Set up standard environment by detaching from the parent. 270 */ 271 daemon(0, 0); 272 #endif 273 274 openlog("lpd", LOG_PID, LOG_LPR); 275 syslog(LOG_INFO, "lpd startup: logging=%d%s%s", lflag, 276 socket_debug ? " dbg" : "", sflag ? " net-secure" : ""); 277 (void) umask(0); 278 /* 279 * NB: This depends on O_NONBLOCK semantics doing the right thing; 280 * i.e., applying only to the O_EXLOCK and not to the rest of the 281 * open/creation. As of 1997-12-02, this is the case for commonly- 282 * used filesystems. There are other places in this code which 283 * make the same assumption. 284 */ 285 lfd = open(_PATH_MASTERLOCK, O_WRONLY|O_CREAT|O_EXLOCK|O_NONBLOCK, 286 LOCK_FILE_MODE); 287 if (lfd < 0) { 288 if (errno == EWOULDBLOCK) /* active daemon present */ 289 exit(0); 290 syslog(LOG_ERR, "%s: %m", _PATH_MASTERLOCK); 291 exit(1); 292 } 293 fcntl(lfd, F_SETFL, 0); /* turn off non-blocking mode */ 294 ftruncate(lfd, 0); 295 /* 296 * write process id for others to know 297 */ 298 sprintf(line, "%u\n", getpid()); 299 f = strlen(line); 300 if (write(lfd, line, f) != f) { 301 syslog(LOG_ERR, "%s: %m", _PATH_MASTERLOCK); 302 exit(1); 303 } 304 signal(SIGCHLD, reapchild); 305 /* 306 * Restart all the printers. 307 */ 308 startup(); 309 (void) unlink(_PATH_SOCKETNAME); 310 funix = socket(AF_UNIX, SOCK_STREAM, 0); 311 if (funix < 0) { 312 syslog(LOG_ERR, "socket: %m"); 313 exit(1); 314 } 315 316 sigemptyset(&nmask); 317 sigaddset(&nmask, SIGHUP); 318 sigaddset(&nmask, SIGINT); 319 sigaddset(&nmask, SIGQUIT); 320 sigaddset(&nmask, SIGTERM); 321 sigprocmask(SIG_BLOCK, &nmask, &omask); 322 323 (void) umask(07); 324 signal(SIGHUP, mcleanup); 325 signal(SIGINT, mcleanup); 326 signal(SIGQUIT, mcleanup); 327 signal(SIGTERM, mcleanup); 328 memset(&un, 0, sizeof(un)); 329 un.sun_family = AF_UNIX; 330 strcpy(un.sun_path, _PATH_SOCKETNAME); 331 #ifndef SUN_LEN 332 #define SUN_LEN(unp) (strlen((unp)->sun_path) + 2) 333 #endif 334 if (bind(funix, (struct sockaddr *)&un, SUN_LEN(&un)) < 0) { 335 syslog(LOG_ERR, "ubind: %m"); 336 exit(1); 337 } 338 (void) umask(0); 339 sigprocmask(SIG_SETMASK, &omask, (sigset_t *)0); 340 FD_ZERO(&defreadfds); 341 FD_SET(funix, &defreadfds); 342 listen(funix, 5); 343 if (sflag == 0) { 344 finet = socksetup(family, socket_debug); 345 } else 346 finet = NULL; /* pretend we couldn't open TCP socket. */ 347 if (finet) { 348 for (i = 1; i <= *finet; i++) { 349 FD_SET(finet[i], &defreadfds); 350 listen(finet[i], 5); 351 } 352 } 353 /* 354 * Main loop: accept, do a request, continue. 355 */ 356 memset(&frominet, 0, sizeof(frominet)); 357 memset(&fromunix, 0, sizeof(fromunix)); 358 if (lflag) 359 syslog(LOG_INFO, "lpd startup: ready to accept requests"); 360 /* 361 * XXX - should be redone for multi-protocol 362 */ 363 for (;;) { 364 int domain, nfds, s; 365 fd_set readfds; 366 367 FD_COPY(&defreadfds, &readfds); 368 nfds = select(20, &readfds, 0, 0, 0); 369 if (nfds <= 0) { 370 if (nfds < 0 && errno != EINTR) 371 syslog(LOG_WARNING, "select: %m"); 372 continue; 373 } 374 domain = -1; /* avoid compile-time warning */ 375 s = -1; /* avoid compile-time warning */ 376 if (FD_ISSET(funix, &readfds)) { 377 domain = AF_UNIX, fromlen = sizeof(fromunix); 378 s = accept(funix, 379 (struct sockaddr *)&fromunix, &fromlen); 380 } else { 381 for (i = 1; i <= *finet; i++) 382 if (FD_ISSET(finet[i], &readfds)) { 383 domain = AF_INET; 384 fromlen = sizeof(frominet); 385 s = accept(finet[i], 386 (struct sockaddr *)&frominet, 387 &fromlen); 388 } 389 } 390 if (s < 0) { 391 if (errno != EINTR) 392 syslog(LOG_WARNING, "accept: %m"); 393 continue; 394 } 395 if (fork() == 0) { 396 /* 397 * Note that printjob() also plays around with 398 * signal-handling routines, and may need to be 399 * changed when making changes to signal-handling. 400 */ 401 signal(SIGCHLD, SIG_DFL); 402 signal(SIGHUP, SIG_IGN); 403 signal(SIGINT, SIG_IGN); 404 signal(SIGQUIT, SIG_IGN); 405 signal(SIGTERM, SIG_IGN); 406 (void) close(funix); 407 if (sflag == 0 && finet) { 408 for (i = 1; i <= *finet; i++) 409 (void)close(finet[i]); 410 } 411 dup2(s, STDOUT_FILENO); 412 (void) close(s); 413 if (domain == AF_INET) { 414 /* for both AF_INET and AF_INET6 */ 415 from_remote = 1; 416 chkhost((struct sockaddr *)&frominet, 417 ch_options); 418 } else 419 from_remote = 0; 420 doit(); 421 exit(0); 422 } 423 (void) close(s); 424 } 425 } 426 427 static void 428 reapchild(int signo __unused) 429 { 430 int status; 431 432 while (wait3(&status, WNOHANG, 0) > 0) 433 ; 434 } 435 436 static void 437 mcleanup(int signo) 438 { 439 /* 440 * XXX syslog(3) is not signal-safe. 441 */ 442 if (lflag) { 443 if (signo) 444 syslog(LOG_INFO, "exiting on signal %d", signo); 445 else 446 syslog(LOG_INFO, "exiting"); 447 } 448 unlink(_PATH_SOCKETNAME); 449 exit(0); 450 } 451 452 /* 453 * Stuff for handling job specifications 454 */ 455 char *user[MAXUSERS]; /* users to process */ 456 int users; /* # of users in user array */ 457 int requ[MAXREQUESTS]; /* job number of spool entries */ 458 int requests; /* # of spool requests */ 459 char *person; /* name of person doing lprm */ 460 461 /* buffer to hold the client's machine-name */ 462 static char frombuf[MAXHOSTNAMELEN]; 463 char cbuf[BUFSIZ]; /* command line buffer */ 464 const char *cmdnames[] = { 465 "null", 466 "printjob", 467 "recvjob", 468 "displayq short", 469 "displayq long", 470 "rmjob" 471 }; 472 473 static void 474 doit(void) 475 { 476 char *cp, *printer; 477 int n; 478 int status; 479 struct printer myprinter, *pp = &myprinter; 480 481 init_printer(&myprinter); 482 483 for (;;) { 484 cp = cbuf; 485 do { 486 if (cp >= &cbuf[sizeof(cbuf) - 1]) 487 fatal(0, "Command line too long"); 488 if ((n = read(STDOUT_FILENO, cp, 1)) != 1) { 489 if (n < 0) 490 fatal(0, "Lost connection"); 491 return; 492 } 493 } while (*cp++ != '\n'); 494 *--cp = '\0'; 495 cp = cbuf; 496 if (lflag) { 497 if (*cp >= '\1' && *cp <= '\5') 498 syslog(LOG_INFO, "%s requests %s %s", 499 from_host, cmdnames[(u_char)*cp], cp+1); 500 else 501 syslog(LOG_INFO, "bad request (%d) from %s", 502 *cp, from_host); 503 } 504 switch (*cp++) { 505 case CMD_CHECK_QUE: /* check the queue, print any jobs there */ 506 startprinting(cp); 507 break; 508 case CMD_TAKE_THIS: /* receive files to be queued */ 509 if (!from_remote) { 510 syslog(LOG_INFO, "illegal request (%d)", *cp); 511 exit(1); 512 } 513 recvjob(cp); 514 break; 515 case CMD_SHOWQ_SHORT: /* display the queue (short form) */ 516 case CMD_SHOWQ_LONG: /* display the queue (long form) */ 517 /* XXX - this all needs to be redone. */ 518 printer = cp; 519 while (*cp) { 520 if (*cp != ' ') { 521 cp++; 522 continue; 523 } 524 *cp++ = '\0'; 525 while (isspace(*cp)) 526 cp++; 527 if (*cp == '\0') 528 break; 529 if (isdigit(*cp)) { 530 if (requests >= MAXREQUESTS) 531 fatal(0, "Too many requests"); 532 requ[requests++] = atoi(cp); 533 } else { 534 if (users >= MAXUSERS) 535 fatal(0, "Too many users"); 536 user[users++] = cp; 537 } 538 } 539 status = getprintcap(printer, pp); 540 if (status < 0) 541 fatal(pp, "%s", pcaperr(status)); 542 displayq(pp, cbuf[0] == CMD_SHOWQ_LONG); 543 exit(0); 544 case CMD_RMJOB: /* remove a job from the queue */ 545 if (!from_remote) { 546 syslog(LOG_INFO, "illegal request (%d)", *cp); 547 exit(1); 548 } 549 printer = cp; 550 while (*cp && *cp != ' ') 551 cp++; 552 if (!*cp) 553 break; 554 *cp++ = '\0'; 555 person = cp; 556 while (*cp) { 557 if (*cp != ' ') { 558 cp++; 559 continue; 560 } 561 *cp++ = '\0'; 562 while (isspace(*cp)) 563 cp++; 564 if (*cp == '\0') 565 break; 566 if (isdigit(*cp)) { 567 if (requests >= MAXREQUESTS) 568 fatal(0, "Too many requests"); 569 requ[requests++] = atoi(cp); 570 } else { 571 if (users >= MAXUSERS) 572 fatal(0, "Too many users"); 573 user[users++] = cp; 574 } 575 } 576 rmjob(printer); 577 break; 578 } 579 fatal(0, "Illegal service request"); 580 } 581 } 582 583 /* 584 * Make a pass through the printcap database and start printing any 585 * files left from the last time the machine went down. 586 */ 587 static void 588 startup(void) 589 { 590 int pid, status, more; 591 struct printer myprinter, *pp = &myprinter; 592 593 more = firstprinter(pp, &status); 594 if (status) 595 goto errloop; 596 while (more) { 597 if (ckqueue(pp) <= 0) { 598 goto next; 599 } 600 if (lflag) 601 syslog(LOG_INFO, "lpd startup: work for %s", 602 pp->printer); 603 if ((pid = fork()) < 0) { 604 syslog(LOG_WARNING, "lpd startup: cannot fork for %s", 605 pp->printer); 606 mcleanup(0); 607 } 608 if (pid == 0) { 609 lastprinter(); 610 printjob(pp); 611 /* NOTREACHED */ 612 } 613 do { 614 next: 615 more = nextprinter(pp, &status); 616 errloop: 617 if (status) 618 syslog(LOG_WARNING, 619 "lpd startup: printcap entry for %s has errors, skipping", 620 pp->printer ? pp->printer : "<noname?>"); 621 } while (more && status); 622 } 623 } 624 625 /* 626 * Make sure there's some work to do before forking off a child 627 */ 628 static int 629 ckqueue(struct printer *pp) 630 { 631 register struct dirent *d; 632 DIR *dirp; 633 char *spooldir; 634 635 spooldir = pp->spool_dir; 636 if ((dirp = opendir(spooldir)) == NULL) 637 return (-1); 638 while ((d = readdir(dirp)) != NULL) { 639 if (d->d_name[0] != 'c' || d->d_name[1] != 'f') 640 continue; /* daemon control files only */ 641 closedir(dirp); 642 return (1); /* found something */ 643 } 644 closedir(dirp); 645 return (0); 646 } 647 648 #define DUMMY ":nobody::" 649 650 /* 651 * Check to see if the host connecting to this host has access to any 652 * lpd services on this host. 653 */ 654 static void 655 chkhost(struct sockaddr *f, int ch_opts) 656 { 657 struct addrinfo hints, *res, *r; 658 register FILE *hostf; 659 char hostbuf[NI_MAXHOST], ip[NI_MAXHOST]; 660 char serv[NI_MAXSERV]; 661 char *syserr, *usererr; 662 int error, errsav, fpass, good; 663 664 from_host = ".na."; 665 666 /* Need real hostname for temporary filenames */ 667 error = getnameinfo(f, f->sa_len, hostbuf, sizeof(hostbuf), NULL, 0, 668 NI_NAMEREQD); 669 if (error) { 670 errsav = error; 671 error = getnameinfo(f, f->sa_len, hostbuf, sizeof(hostbuf), 672 NULL, 0, NI_NUMERICHOST); 673 if (error) { 674 asprintf(&syserr, 675 "can not determine hostname for remote host (%d,%d)", 676 errsav, error); 677 asprintf(&usererr, 678 "Host name for your address is not known"); 679 fhosterr(ch_opts, syserr, usererr); 680 /* NOTREACHED */ 681 } 682 asprintf(&syserr, 683 "Host name for remote host (%s) not known (%d)", 684 hostbuf, errsav); 685 asprintf(&usererr, 686 "Host name for your address (%s) is not known", 687 hostbuf); 688 fhosterr(ch_opts, syserr, usererr); 689 /* NOTREACHED */ 690 } 691 692 strlcpy(frombuf, hostbuf, sizeof(frombuf)); 693 from_host = frombuf; 694 ch_opts |= LPD_ADDFROMLINE; 695 696 /* Need address in stringform for comparison (no DNS lookup here) */ 697 error = getnameinfo(f, f->sa_len, hostbuf, sizeof(hostbuf), NULL, 0, 698 NI_NUMERICHOST); 699 if (error) { 700 asprintf(&syserr, "Cannot print IP address (error %d)", 701 error); 702 asprintf(&usererr, "Cannot print IP address for your host"); 703 fhosterr(ch_opts, syserr, usererr); 704 /* NOTREACHED */ 705 } 706 from_ip = strdup(hostbuf); 707 708 /* Reject numeric addresses */ 709 memset(&hints, 0, sizeof(hints)); 710 hints.ai_family = family; 711 hints.ai_socktype = SOCK_DGRAM; /*dummy*/ 712 hints.ai_flags = AI_PASSIVE | AI_NUMERICHOST; 713 if (getaddrinfo(from_host, NULL, &hints, &res) == 0) { 714 freeaddrinfo(res); 715 /* This syslog message already includes from_host */ 716 ch_opts &= ~LPD_ADDFROMLINE; 717 asprintf(&syserr, "reverse lookup results in non-FQDN %s", 718 from_host); 719 /* same message to both syslog and remote user */ 720 fhosterr(ch_opts, syserr, syserr); 721 /* NOTREACHED */ 722 } 723 724 /* Check for spoof, ala rlogind */ 725 memset(&hints, 0, sizeof(hints)); 726 hints.ai_family = family; 727 hints.ai_socktype = SOCK_DGRAM; /*dummy*/ 728 error = getaddrinfo(from_host, NULL, &hints, &res); 729 if (error) { 730 asprintf(&syserr, "dns lookup for address %s failed: %s", 731 from_ip, gai_strerror(error)); 732 asprintf(&usererr, "hostname for your address (%s) unknown: %s", 733 from_ip, gai_strerror(error)); 734 fhosterr(ch_opts, syserr, usererr); 735 /* NOTREACHED */ 736 } 737 good = 0; 738 for (r = res; good == 0 && r; r = r->ai_next) { 739 error = getnameinfo(r->ai_addr, r->ai_addrlen, ip, sizeof(ip), 740 NULL, 0, NI_NUMERICHOST); 741 if (!error && !strcmp(from_ip, ip)) 742 good = 1; 743 } 744 if (res) 745 freeaddrinfo(res); 746 if (good == 0) { 747 asprintf(&syserr, "address for remote host (%s) not matched", 748 from_ip); 749 asprintf(&usererr, 750 "address for your hostname (%s) not matched", from_ip); 751 fhosterr(ch_opts, syserr, usererr); 752 /* NOTREACHED */ 753 } 754 755 fpass = 1; 756 hostf = fopen(_PATH_HOSTSEQUIV, "r"); 757 again: 758 if (hostf) { 759 if (__ivaliduser_sa(hostf, f, f->sa_len, DUMMY, DUMMY) == 0) { 760 (void) fclose(hostf); 761 goto foundhost; 762 } 763 (void) fclose(hostf); 764 } 765 if (fpass == 1) { 766 fpass = 2; 767 hostf = fopen(_PATH_HOSTSLPD, "r"); 768 goto again; 769 } 770 /* This syslog message already includes from_host */ 771 ch_opts &= ~LPD_ADDFROMLINE; 772 asprintf(&syserr, "refused connection from %s, sip=%s", from_host, 773 from_ip); 774 asprintf(&usererr, 775 "Print-services are not available to your host (%s).", from_host); 776 fhosterr(ch_opts, syserr, usererr); 777 /* NOTREACHED */ 778 779 foundhost: 780 if (ch_opts & LPD_NOPORTCHK) 781 return; /* skip the reserved-port check */ 782 783 error = getnameinfo(f, f->sa_len, NULL, 0, serv, sizeof(serv), 784 NI_NUMERICSERV); 785 if (error) { 786 /* same message to both syslog and remote user */ 787 asprintf(&syserr, "malformed from-address (%d)", error); 788 fhosterr(ch_opts, syserr, syserr); 789 /* NOTREACHED */ 790 } 791 792 if (atoi(serv) >= IPPORT_RESERVED) { 793 /* same message to both syslog and remote user */ 794 asprintf(&syserr, "connected from invalid port (%s)", serv); 795 fhosterr(ch_opts, syserr, syserr); 796 /* NOTREACHED */ 797 } 798 } 799 800 /* 801 * Handle fatal errors in chkhost. The first message will optionally be 802 * sent to syslog, the second one is sent to the connecting host. 803 * 804 * The idea is that the syslog message is meant for an administrator of a 805 * print server (the host receiving connections), while the usermsg is meant 806 * for a remote user who may or may not be clueful, and may or may not be 807 * doing something nefarious. Some remote users (eg, MS-Windows...) may not 808 * even see whatever message is sent, which is why there's the option to 809 * start 'lpd' with the connection-errors also sent to syslog. 810 * 811 * Given that hostnames can theoretically be fairly long (well, over 250 812 * bytes), it would probably be helpful to have the 'from_host' field at 813 * the end of any error messages which include that info. 814 * 815 * These are Fatal host-connection errors, so this routine does not return. 816 */ 817 static void 818 fhosterr(int ch_opts, char *sysmsg, char *usermsg) 819 { 820 821 /* 822 * If lpd was started up to print connection errors, then write 823 * the syslog message before the user message. 824 * And for many of the syslog messages, it is helpful to first 825 * write the from_host (if it is known) as a separate syslog 826 * message, since the hostname may be so long. 827 */ 828 if (ch_opts & LPD_LOGCONNERR) { 829 if (ch_opts & LPD_ADDFROMLINE) { 830 syslog(LOG_WARNING, "for connection from %s:", from_host); 831 } 832 syslog(LOG_WARNING, "%s", sysmsg); 833 } 834 835 /* 836 * Now send the error message to the remote host which is trying 837 * to make the connection. 838 */ 839 printf("%s [@%s]: %s\n", progname, local_host, usermsg); 840 fflush(stdout); 841 842 /* 843 * Add a minimal delay before exiting (and disconnecting from the 844 * sending-host). This is just in case that machine responds by 845 * INSTANTLY retrying (and instantly re-failing...). This may also 846 * give the other side more time to read the error message. 847 */ 848 sleep(2); /* a paranoid throttling measure */ 849 exit(1); 850 } 851 852 /* setup server socket for specified address family */ 853 /* if af is PF_UNSPEC more than one socket may be returned */ 854 /* the returned list is dynamically allocated, so caller needs to free it */ 855 static int * 856 socksetup(int af, int debuglvl) 857 { 858 struct addrinfo hints, *res, *r; 859 int error, maxs, *s, *socks; 860 const int on = 1; 861 862 memset(&hints, 0, sizeof(hints)); 863 hints.ai_flags = AI_PASSIVE; 864 hints.ai_family = af; 865 hints.ai_socktype = SOCK_STREAM; 866 error = getaddrinfo(NULL, "printer", &hints, &res); 867 if (error) { 868 syslog(LOG_ERR, "%s", gai_strerror(error)); 869 mcleanup(0); 870 } 871 872 /* Count max number of sockets we may open */ 873 for (maxs = 0, r = res; r; r = r->ai_next, maxs++) 874 ; 875 socks = malloc((maxs + 1) * sizeof(int)); 876 if (!socks) { 877 syslog(LOG_ERR, "couldn't allocate memory for sockets"); 878 mcleanup(0); 879 } 880 881 *socks = 0; /* num of sockets counter at start of array */ 882 s = socks + 1; 883 for (r = res; r; r = r->ai_next) { 884 *s = socket(r->ai_family, r->ai_socktype, r->ai_protocol); 885 if (*s < 0) { 886 syslog(LOG_DEBUG, "socket(): %m"); 887 continue; 888 } 889 if (setsockopt(*s, SOL_SOCKET, SO_REUSEADDR, &on, sizeof(on)) 890 < 0) { 891 syslog(LOG_ERR, "setsockopt(SO_REUSEADDR): %m"); 892 close(*s); 893 continue; 894 } 895 if (debuglvl) 896 if (setsockopt(*s, SOL_SOCKET, SO_DEBUG, &debuglvl, 897 sizeof(debuglvl)) < 0) { 898 syslog(LOG_ERR, "setsockopt (SO_DEBUG): %m"); 899 close(*s); 900 continue; 901 } 902 if (r->ai_family == AF_INET6) { 903 if (setsockopt(*s, IPPROTO_IPV6, IPV6_V6ONLY, 904 &on, sizeof(on)) < 0) { 905 syslog(LOG_ERR, 906 "setsockopt (IPV6_V6ONLY): %m"); 907 close(*s); 908 continue; 909 } 910 } 911 if (bind(*s, r->ai_addr, r->ai_addrlen) < 0) { 912 syslog(LOG_DEBUG, "bind(): %m"); 913 close(*s); 914 continue; 915 } 916 (*socks)++; 917 s++; 918 } 919 920 if (res) 921 freeaddrinfo(res); 922 923 if (*socks == 0) { 924 syslog(LOG_ERR, "Couldn't bind to any socket"); 925 free(socks); 926 mcleanup(0); 927 } 928 return(socks); 929 } 930 931 static void 932 usage(void) 933 { 934 #ifdef INET6 935 fprintf(stderr, "usage: lpd [-cdlsW46] [port#]\n"); 936 #else 937 fprintf(stderr, "usage: lpd [-cdlsW] [port#]\n"); 938 #endif 939 exit(EX_USAGE); 940 } 941