1 /* 2 * Copyright (c) 1983, 1993, 1994 3 * The Regents of the University of California. All rights reserved. 4 * 5 * 6 * Redistribution and use in source and binary forms, with or without 7 * modification, are permitted provided that the following conditions 8 * are met: 9 * 1. Redistributions of source code must retain the above copyright 10 * notice, this list of conditions and the following disclaimer. 11 * 2. Redistributions in binary form must reproduce the above copyright 12 * notice, this list of conditions and the following disclaimer in the 13 * documentation and/or other materials provided with the distribution. 14 * 3. All advertising materials mentioning features or use of this software 15 * must display the following acknowledgement: 16 * This product includes software developed by the University of 17 * California, Berkeley and its contributors. 18 * 4. Neither the name of the University nor the names of its contributors 19 * may be used to endorse or promote products derived from this software 20 * without specific prior written permission. 21 * 22 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 23 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 24 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 25 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 26 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 27 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 28 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 29 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 30 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 31 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 32 * SUCH DAMAGE. 33 */ 34 35 #ifndef lint 36 static const char copyright[] = 37 "@(#) Copyright (c) 1983, 1993, 1994\n\ 38 The Regents of the University of California. All rights reserved.\n"; 39 #endif /* not lint */ 40 41 #if 0 42 #ifndef lint 43 static char sccsid[] = "@(#)lpd.c 8.7 (Berkeley) 5/10/95"; 44 #endif /* not lint */ 45 #endif 46 47 #include "lp.cdefs.h" /* A cross-platform version of <sys/cdefs.h> */ 48 __FBSDID("$FreeBSD$"); 49 50 /* 51 * lpd -- line printer daemon. 52 * 53 * Listen for a connection and perform the requested operation. 54 * Operations are: 55 * \1printer\n 56 * check the queue for jobs and print any found. 57 * \2printer\n 58 * receive a job from another machine and queue it. 59 * \3printer [users ...] [jobs ...]\n 60 * return the current state of the queue (short form). 61 * \4printer [users ...] [jobs ...]\n 62 * return the current state of the queue (long form). 63 * \5printer person [users ...] [jobs ...]\n 64 * remove jobs from the queue. 65 * 66 * Strategy to maintain protected spooling area: 67 * 1. Spooling area is writable only by daemon and spooling group 68 * 2. lpr runs setuid root and setgrp spooling group; it uses 69 * root to access any file it wants (verifying things before 70 * with an access call) and group id to know how it should 71 * set up ownership of files in the spooling area. 72 * 3. Files in spooling area are owned by root, group spooling 73 * group, with mode 660. 74 * 4. lpd, lpq and lprm run setuid daemon and setgrp spooling group to 75 * access files and printer. Users can't get to anything 76 * w/o help of lpq and lprm programs. 77 */ 78 79 #include <sys/param.h> 80 #include <sys/wait.h> 81 #include <sys/types.h> 82 #include <sys/socket.h> 83 #include <sys/un.h> 84 #include <sys/stat.h> 85 #include <sys/file.h> 86 #include <netinet/in.h> 87 #include <arpa/inet.h> 88 89 #include <netdb.h> 90 #include <unistd.h> 91 #include <syslog.h> 92 #include <signal.h> 93 #include <err.h> 94 #include <errno.h> 95 #include <fcntl.h> 96 #include <dirent.h> 97 #include <stdio.h> 98 #include <stdlib.h> 99 #include <string.h> 100 #include <sysexits.h> 101 #include <ctype.h> 102 #include "lp.h" 103 #include "lp.local.h" 104 #include "pathnames.h" 105 #include "extern.h" 106 107 int lflag; /* log requests flag */ 108 int sflag; /* no incoming port flag */ 109 int from_remote; /* from remote socket */ 110 111 int main(int argc, char **_argv); 112 static void reapchild(int _signo); 113 static void mcleanup(int _signo); 114 static void doit(void); 115 static void startup(void); 116 static void chkhost(struct sockaddr *_f, int _ch_opts); 117 static int ckqueue(struct printer *_pp); 118 static void fhosterr(int _ch_opts, char *_sysmsg, char *_usermsg); 119 static int *socksetup(int _af, int _debuglvl); 120 static void usage(void); 121 122 /* XXX from libc/net/rcmd.c */ 123 extern int __ivaliduser_sa __P((FILE *, struct sockaddr *, socklen_t, 124 const char *, const char *)); 125 126 uid_t uid, euid; 127 128 #define LPD_NOPORTCHK 0001 /* skip reserved-port check */ 129 #define LPD_LOGCONNERR 0002 /* (sys)log connection errors */ 130 #define LPD_ADDFROMLINE 0004 /* just used for fhosterr() */ 131 132 int 133 main(int argc, char **argv) 134 { 135 int ch_options, errs, f, funix, *finet, i, lfd, socket_debug; 136 fd_set defreadfds; 137 struct sockaddr_un un, fromunix; 138 struct sockaddr_storage frominet; 139 socklen_t fromlen; 140 sigset_t omask, nmask; 141 struct servent *sp, serv; 142 int inet_flag = 0, inet6_flag = 0; 143 144 euid = geteuid(); /* these shouldn't be different */ 145 uid = getuid(); 146 147 ch_options = 0; 148 socket_debug = 0; 149 gethostname(local_host, sizeof(local_host)); 150 151 progname = "lpd"; 152 153 if (euid != 0) 154 errx(EX_NOPERM,"must run as root"); 155 156 errs = 0; 157 while ((i = getopt(argc, argv, "cdlpswW46")) != -1) 158 switch (i) { 159 case 'c': 160 /* log all kinds of connection-errors to syslog */ 161 ch_options |= LPD_LOGCONNERR; 162 break; 163 case 'd': 164 socket_debug++; 165 break; 166 case 'l': 167 lflag++; 168 break; 169 case 'p': /* letter initially used for -s */ 170 /* 171 * This will probably be removed with 5.0-release. 172 */ 173 /* FALLTHROUGH */ 174 case 's': /* secure (no inet) */ 175 sflag++; 176 break; 177 case 'w': /* netbsd uses -w for maxwait */ 178 /* 179 * This will be removed after the release of 4.4, as 180 * it conflicts with -w in netbsd's lpd. For now it 181 * is just a warning, so we won't suddenly break lpd 182 * for anyone who is currently using the option. 183 */ 184 syslog(LOG_WARNING, 185 "NOTE: the -w option has been renamed -W"); 186 syslog(LOG_WARNING, 187 "NOTE: please change your lpd config to use -W"); 188 /* FALLTHROUGH */ 189 case 'W': 190 /* allow connections coming from a non-reserved port */ 191 /* (done by some lpr-implementations for MS-Windows) */ 192 ch_options |= LPD_NOPORTCHK; 193 break; 194 case '4': 195 family = PF_INET; 196 inet_flag++; 197 break; 198 case '6': 199 #ifdef INET6 200 family = PF_INET6; 201 inet6_flag++; 202 #else 203 errx(EX_USAGE, "lpd compiled sans INET6 (IPv6 support)"); 204 #endif 205 break; 206 /* 207 * The following options are not in FreeBSD (yet?), but are 208 * listed here to "reserve" them, because the option-letters 209 * are used by either NetBSD or OpenBSD (as of July 2001). 210 */ 211 case 'b': /* set bind-addr */ 212 case 'n': /* set max num of children */ 213 case 'r': /* allow 'of' for remote ptrs */ 214 /* ...[not needed in freebsd] */ 215 /* FALLTHROUGH */ 216 default: 217 errs++; 218 } 219 if (inet_flag && inet6_flag) 220 family = PF_UNSPEC; 221 argc -= optind; 222 argv += optind; 223 if (errs) 224 usage(); 225 226 if (argc == 1) { 227 if ((i = atoi(argv[0])) == 0) 228 usage(); 229 if (i < 0 || i > USHRT_MAX) 230 errx(EX_USAGE, "port # %d is invalid", i); 231 232 serv.s_port = htons(i); 233 sp = &serv; 234 argc--; 235 } else { 236 sp = getservbyname("printer", "tcp"); 237 if (sp == NULL) 238 errx(EX_OSFILE, "printer/tcp: unknown service"); 239 } 240 241 if (argc != 0) 242 usage(); 243 244 /* 245 * We run chkprintcap right away to catch any errors and blat them 246 * to stderr while we still have it open, rather than sending them 247 * to syslog and leaving the user wondering why lpd started and 248 * then stopped. There should probably be a command-line flag to 249 * ignore errors from chkprintcap. 250 */ 251 { 252 pid_t pid; 253 int status; 254 pid = fork(); 255 if (pid < 0) { 256 err(EX_OSERR, "cannot fork"); 257 } else if (pid == 0) { /* child */ 258 execl(_PATH_CHKPRINTCAP, _PATH_CHKPRINTCAP, (char *)0); 259 err(EX_OSERR, "cannot execute %s", _PATH_CHKPRINTCAP); 260 } 261 if (waitpid(pid, &status, 0) < 0) { 262 err(EX_OSERR, "cannot wait"); 263 } 264 if (WIFEXITED(status) && WEXITSTATUS(status) != 0) 265 errx(EX_OSFILE, "%d errors in printcap file, exiting", 266 WEXITSTATUS(status)); 267 } 268 269 #ifndef DEBUG 270 /* 271 * Set up standard environment by detaching from the parent. 272 */ 273 daemon(0, 0); 274 #endif 275 276 openlog("lpd", LOG_PID, LOG_LPR); 277 syslog(LOG_INFO, "lpd startup: logging=%d%s%s", lflag, 278 socket_debug ? " dbg" : "", sflag ? " net-secure" : ""); 279 (void) umask(0); 280 /* 281 * NB: This depends on O_NONBLOCK semantics doing the right thing; 282 * i.e., applying only to the O_EXLOCK and not to the rest of the 283 * open/creation. As of 1997-12-02, this is the case for commonly- 284 * used filesystems. There are other places in this code which 285 * make the same assumption. 286 */ 287 lfd = open(_PATH_MASTERLOCK, O_WRONLY|O_CREAT|O_EXLOCK|O_NONBLOCK, 288 LOCK_FILE_MODE); 289 if (lfd < 0) { 290 if (errno == EWOULDBLOCK) /* active daemon present */ 291 exit(0); 292 syslog(LOG_ERR, "%s: %m", _PATH_MASTERLOCK); 293 exit(1); 294 } 295 fcntl(lfd, F_SETFL, 0); /* turn off non-blocking mode */ 296 ftruncate(lfd, 0); 297 /* 298 * write process id for others to know 299 */ 300 sprintf(line, "%u\n", getpid()); 301 f = strlen(line); 302 if (write(lfd, line, f) != f) { 303 syslog(LOG_ERR, "%s: %m", _PATH_MASTERLOCK); 304 exit(1); 305 } 306 signal(SIGCHLD, reapchild); 307 /* 308 * Restart all the printers. 309 */ 310 startup(); 311 (void) unlink(_PATH_SOCKETNAME); 312 funix = socket(AF_UNIX, SOCK_STREAM, 0); 313 if (funix < 0) { 314 syslog(LOG_ERR, "socket: %m"); 315 exit(1); 316 } 317 318 sigemptyset(&nmask); 319 sigaddset(&nmask, SIGHUP); 320 sigaddset(&nmask, SIGINT); 321 sigaddset(&nmask, SIGQUIT); 322 sigaddset(&nmask, SIGTERM); 323 sigprocmask(SIG_BLOCK, &nmask, &omask); 324 325 (void) umask(07); 326 signal(SIGHUP, mcleanup); 327 signal(SIGINT, mcleanup); 328 signal(SIGQUIT, mcleanup); 329 signal(SIGTERM, mcleanup); 330 memset(&un, 0, sizeof(un)); 331 un.sun_family = AF_UNIX; 332 strcpy(un.sun_path, _PATH_SOCKETNAME); 333 #ifndef SUN_LEN 334 #define SUN_LEN(unp) (strlen((unp)->sun_path) + 2) 335 #endif 336 if (bind(funix, (struct sockaddr *)&un, SUN_LEN(&un)) < 0) { 337 syslog(LOG_ERR, "ubind: %m"); 338 exit(1); 339 } 340 (void) umask(0); 341 sigprocmask(SIG_SETMASK, &omask, (sigset_t *)0); 342 FD_ZERO(&defreadfds); 343 FD_SET(funix, &defreadfds); 344 listen(funix, 5); 345 if (sflag == 0) { 346 finet = socksetup(family, socket_debug); 347 } else 348 finet = NULL; /* pretend we couldn't open TCP socket. */ 349 if (finet) { 350 for (i = 1; i <= *finet; i++) { 351 FD_SET(finet[i], &defreadfds); 352 listen(finet[i], 5); 353 } 354 } 355 /* 356 * Main loop: accept, do a request, continue. 357 */ 358 memset(&frominet, 0, sizeof(frominet)); 359 memset(&fromunix, 0, sizeof(fromunix)); 360 if (lflag) 361 syslog(LOG_INFO, "lpd startup: ready to accept requests"); 362 /* 363 * XXX - should be redone for multi-protocol 364 */ 365 for (;;) { 366 int domain, nfds, s; 367 fd_set readfds; 368 369 FD_COPY(&defreadfds, &readfds); 370 nfds = select(20, &readfds, 0, 0, 0); 371 if (nfds <= 0) { 372 if (nfds < 0 && errno != EINTR) 373 syslog(LOG_WARNING, "select: %m"); 374 continue; 375 } 376 domain = -1; /* avoid compile-time warning */ 377 s = -1; /* avoid compile-time warning */ 378 if (FD_ISSET(funix, &readfds)) { 379 domain = AF_UNIX, fromlen = sizeof(fromunix); 380 s = accept(funix, 381 (struct sockaddr *)&fromunix, &fromlen); 382 } else { 383 for (i = 1; i <= *finet; i++) 384 if (FD_ISSET(finet[i], &readfds)) { 385 domain = AF_INET; 386 fromlen = sizeof(frominet); 387 s = accept(finet[i], 388 (struct sockaddr *)&frominet, 389 &fromlen); 390 } 391 } 392 if (s < 0) { 393 if (errno != EINTR) 394 syslog(LOG_WARNING, "accept: %m"); 395 continue; 396 } 397 if (fork() == 0) { 398 /* 399 * Note that printjob() also plays around with 400 * signal-handling routines, and may need to be 401 * changed when making changes to signal-handling. 402 */ 403 signal(SIGCHLD, SIG_DFL); 404 signal(SIGHUP, SIG_IGN); 405 signal(SIGINT, SIG_IGN); 406 signal(SIGQUIT, SIG_IGN); 407 signal(SIGTERM, SIG_IGN); 408 (void) close(funix); 409 if (sflag == 0 && finet) { 410 for (i = 1; i <= *finet; i++) 411 (void)close(finet[i]); 412 } 413 dup2(s, STDOUT_FILENO); 414 (void) close(s); 415 if (domain == AF_INET) { 416 /* for both AF_INET and AF_INET6 */ 417 from_remote = 1; 418 chkhost((struct sockaddr *)&frominet, 419 ch_options); 420 } else 421 from_remote = 0; 422 doit(); 423 exit(0); 424 } 425 (void) close(s); 426 } 427 } 428 429 static void 430 reapchild(int signo __unused) 431 { 432 int status; 433 434 while (wait3(&status, WNOHANG, 0) > 0) 435 ; 436 } 437 438 static void 439 mcleanup(int signo) 440 { 441 /* 442 * XXX syslog(3) is not signal-safe. 443 */ 444 if (lflag) { 445 if (signo) 446 syslog(LOG_INFO, "exiting on signal %d", signo); 447 else 448 syslog(LOG_INFO, "exiting"); 449 } 450 unlink(_PATH_SOCKETNAME); 451 exit(0); 452 } 453 454 /* 455 * Stuff for handling job specifications 456 */ 457 char *user[MAXUSERS]; /* users to process */ 458 int users; /* # of users in user array */ 459 int requ[MAXREQUESTS]; /* job number of spool entries */ 460 int requests; /* # of spool requests */ 461 char *person; /* name of person doing lprm */ 462 463 /* buffer to hold the client's machine-name */ 464 static char frombuf[MAXHOSTNAMELEN]; 465 char cbuf[BUFSIZ]; /* command line buffer */ 466 const char *cmdnames[] = { 467 "null", 468 "printjob", 469 "recvjob", 470 "displayq short", 471 "displayq long", 472 "rmjob" 473 }; 474 475 static void 476 doit(void) 477 { 478 char *cp, *printer; 479 int n; 480 int status; 481 struct printer myprinter, *pp = &myprinter; 482 483 init_printer(&myprinter); 484 485 for (;;) { 486 cp = cbuf; 487 do { 488 if (cp >= &cbuf[sizeof(cbuf) - 1]) 489 fatal(0, "Command line too long"); 490 if ((n = read(STDOUT_FILENO, cp, 1)) != 1) { 491 if (n < 0) 492 fatal(0, "Lost connection"); 493 return; 494 } 495 } while (*cp++ != '\n'); 496 *--cp = '\0'; 497 cp = cbuf; 498 if (lflag) { 499 if (*cp >= '\1' && *cp <= '\5') 500 syslog(LOG_INFO, "%s requests %s %s", 501 from_host, cmdnames[(u_char)*cp], cp+1); 502 else 503 syslog(LOG_INFO, "bad request (%d) from %s", 504 *cp, from_host); 505 } 506 switch (*cp++) { 507 case CMD_CHECK_QUE: /* check the queue, print any jobs there */ 508 startprinting(cp); 509 break; 510 case CMD_TAKE_THIS: /* receive files to be queued */ 511 if (!from_remote) { 512 syslog(LOG_INFO, "illegal request (%d)", *cp); 513 exit(1); 514 } 515 recvjob(cp); 516 break; 517 case CMD_SHOWQ_SHORT: /* display the queue (short form) */ 518 case CMD_SHOWQ_LONG: /* display the queue (long form) */ 519 /* XXX - this all needs to be redone. */ 520 printer = cp; 521 while (*cp) { 522 if (*cp != ' ') { 523 cp++; 524 continue; 525 } 526 *cp++ = '\0'; 527 while (isspace(*cp)) 528 cp++; 529 if (*cp == '\0') 530 break; 531 if (isdigit(*cp)) { 532 if (requests >= MAXREQUESTS) 533 fatal(0, "Too many requests"); 534 requ[requests++] = atoi(cp); 535 } else { 536 if (users >= MAXUSERS) 537 fatal(0, "Too many users"); 538 user[users++] = cp; 539 } 540 } 541 status = getprintcap(printer, pp); 542 if (status < 0) 543 fatal(pp, "%s", pcaperr(status)); 544 displayq(pp, cbuf[0] == CMD_SHOWQ_LONG); 545 exit(0); 546 case CMD_RMJOB: /* remove a job from the queue */ 547 if (!from_remote) { 548 syslog(LOG_INFO, "illegal request (%d)", *cp); 549 exit(1); 550 } 551 printer = cp; 552 while (*cp && *cp != ' ') 553 cp++; 554 if (!*cp) 555 break; 556 *cp++ = '\0'; 557 person = cp; 558 while (*cp) { 559 if (*cp != ' ') { 560 cp++; 561 continue; 562 } 563 *cp++ = '\0'; 564 while (isspace(*cp)) 565 cp++; 566 if (*cp == '\0') 567 break; 568 if (isdigit(*cp)) { 569 if (requests >= MAXREQUESTS) 570 fatal(0, "Too many requests"); 571 requ[requests++] = atoi(cp); 572 } else { 573 if (users >= MAXUSERS) 574 fatal(0, "Too many users"); 575 user[users++] = cp; 576 } 577 } 578 rmjob(printer); 579 break; 580 } 581 fatal(0, "Illegal service request"); 582 } 583 } 584 585 /* 586 * Make a pass through the printcap database and start printing any 587 * files left from the last time the machine went down. 588 */ 589 static void 590 startup(void) 591 { 592 int pid, status, more; 593 struct printer myprinter, *pp = &myprinter; 594 595 more = firstprinter(pp, &status); 596 if (status) 597 goto errloop; 598 while (more) { 599 if (ckqueue(pp) <= 0) { 600 goto next; 601 } 602 if (lflag) 603 syslog(LOG_INFO, "lpd startup: work for %s", 604 pp->printer); 605 if ((pid = fork()) < 0) { 606 syslog(LOG_WARNING, "lpd startup: cannot fork for %s", 607 pp->printer); 608 mcleanup(0); 609 } 610 if (pid == 0) { 611 lastprinter(); 612 printjob(pp); 613 /* NOTREACHED */ 614 } 615 do { 616 next: 617 more = nextprinter(pp, &status); 618 errloop: 619 if (status) 620 syslog(LOG_WARNING, 621 "lpd startup: printcap entry for %s has errors, skipping", 622 pp->printer ? pp->printer : "<noname?>"); 623 } while (more && status); 624 } 625 } 626 627 /* 628 * Make sure there's some work to do before forking off a child 629 */ 630 static int 631 ckqueue(struct printer *pp) 632 { 633 register struct dirent *d; 634 DIR *dirp; 635 char *spooldir; 636 637 spooldir = pp->spool_dir; 638 if ((dirp = opendir(spooldir)) == NULL) 639 return (-1); 640 while ((d = readdir(dirp)) != NULL) { 641 if (d->d_name[0] != 'c' || d->d_name[1] != 'f') 642 continue; /* daemon control files only */ 643 closedir(dirp); 644 return (1); /* found something */ 645 } 646 closedir(dirp); 647 return (0); 648 } 649 650 #define DUMMY ":nobody::" 651 652 /* 653 * Check to see if the host connecting to this host has access to any 654 * lpd services on this host. 655 */ 656 static void 657 chkhost(struct sockaddr *f, int ch_opts) 658 { 659 struct addrinfo hints, *res, *r; 660 register FILE *hostf; 661 char hostbuf[NI_MAXHOST], ip[NI_MAXHOST]; 662 char serv[NI_MAXSERV]; 663 char *syserr, *usererr; 664 int error, errsav, fpass, good, wantsl; 665 666 wantsl = 0; 667 if (ch_opts & LPD_LOGCONNERR) 668 wantsl = 1; /* also syslog the errors */ 669 670 from_host = ".na."; 671 672 /* Need real hostname for temporary filenames */ 673 error = getnameinfo(f, f->sa_len, hostbuf, sizeof(hostbuf), NULL, 0, 674 NI_NAMEREQD); 675 if (error) { 676 errsav = error; 677 error = getnameinfo(f, f->sa_len, hostbuf, sizeof(hostbuf), 678 NULL, 0, NI_NUMERICHOST | NI_WITHSCOPEID); 679 if (error) { 680 asprintf(&syserr, 681 "can not determine hostname for remote host (%d,%d)", 682 errsav, error); 683 asprintf(&usererr, 684 "Host name for your address is not known"); 685 fhosterr(ch_opts, syserr, usererr); 686 /* NOTREACHED */ 687 } 688 asprintf(&syserr, 689 "Host name for remote host (%s) not known (%d)", 690 hostbuf, errsav); 691 asprintf(&usererr, 692 "Host name for your address (%s) is not known", 693 hostbuf); 694 fhosterr(ch_opts, syserr, usererr); 695 /* NOTREACHED */ 696 } 697 698 strlcpy(frombuf, hostbuf, sizeof(frombuf)); 699 from_host = frombuf; 700 ch_opts |= LPD_ADDFROMLINE; 701 702 /* Need address in stringform for comparison (no DNS lookup here) */ 703 error = getnameinfo(f, f->sa_len, hostbuf, sizeof(hostbuf), NULL, 0, 704 NI_NUMERICHOST | NI_WITHSCOPEID); 705 if (error) { 706 asprintf(&syserr, "Cannot print IP address (error %d)", 707 error); 708 asprintf(&usererr, "Cannot print IP address for your host"); 709 fhosterr(ch_opts, syserr, usererr); 710 /* NOTREACHED */ 711 } 712 from_ip = strdup(hostbuf); 713 714 /* Reject numeric addresses */ 715 memset(&hints, 0, sizeof(hints)); 716 hints.ai_family = family; 717 hints.ai_socktype = SOCK_DGRAM; /*dummy*/ 718 hints.ai_flags = AI_PASSIVE | AI_NUMERICHOST; 719 if (getaddrinfo(from_host, NULL, &hints, &res) == 0) { 720 freeaddrinfo(res); 721 /* This syslog message already includes from_host */ 722 ch_opts &= ~LPD_ADDFROMLINE; 723 asprintf(&syserr, "reverse lookup results in non-FQDN %s", 724 from_host); 725 /* same message to both syslog and remote user */ 726 fhosterr(ch_opts, syserr, syserr); 727 /* NOTREACHED */ 728 } 729 730 /* Check for spoof, ala rlogind */ 731 memset(&hints, 0, sizeof(hints)); 732 hints.ai_family = family; 733 hints.ai_socktype = SOCK_DGRAM; /*dummy*/ 734 error = getaddrinfo(from_host, NULL, &hints, &res); 735 if (error) { 736 asprintf(&syserr, "dns lookup for address %s failed: %s", 737 from_ip, gai_strerror(error)); 738 asprintf(&usererr, "hostname for your address (%s) unknown: %s", 739 from_ip, gai_strerror(error)); 740 fhosterr(ch_opts, syserr, usererr); 741 /* NOTREACHED */ 742 } 743 good = 0; 744 for (r = res; good == 0 && r; r = r->ai_next) { 745 error = getnameinfo(r->ai_addr, r->ai_addrlen, ip, sizeof(ip), 746 NULL, 0, NI_NUMERICHOST | NI_WITHSCOPEID); 747 if (!error && !strcmp(from_ip, ip)) 748 good = 1; 749 } 750 if (res) 751 freeaddrinfo(res); 752 if (good == 0) { 753 asprintf(&syserr, "address for remote host (%s) not matched", 754 from_ip); 755 asprintf(&usererr, 756 "address for your hostname (%s) not matched", from_ip); 757 fhosterr(ch_opts, syserr, usererr); 758 /* NOTREACHED */ 759 } 760 761 fpass = 1; 762 hostf = fopen(_PATH_HOSTSEQUIV, "r"); 763 again: 764 if (hostf) { 765 if (__ivaliduser_sa(hostf, f, f->sa_len, DUMMY, DUMMY) == 0) { 766 (void) fclose(hostf); 767 goto foundhost; 768 } 769 (void) fclose(hostf); 770 } 771 if (fpass == 1) { 772 fpass = 2; 773 hostf = fopen(_PATH_HOSTSLPD, "r"); 774 goto again; 775 } 776 /* This syslog message already includes from_host */ 777 ch_opts &= ~LPD_ADDFROMLINE; 778 asprintf(&syserr, "refused connection from %s, sip=%s", from_host, 779 from_ip); 780 asprintf(&usererr, 781 "Print-services are not available to your host (%s).", from_host); 782 fhosterr(ch_opts, syserr, usererr); 783 /* NOTREACHED */ 784 785 foundhost: 786 if (ch_opts & LPD_NOPORTCHK) 787 return; /* skip the reserved-port check */ 788 789 error = getnameinfo(f, f->sa_len, NULL, 0, serv, sizeof(serv), 790 NI_NUMERICSERV); 791 if (error) { 792 /* same message to both syslog and remote user */ 793 asprintf(&syserr, "malformed from-address (%d)", error); 794 fhosterr(ch_opts, syserr, syserr); 795 /* NOTREACHED */ 796 } 797 798 if (atoi(serv) >= IPPORT_RESERVED) { 799 /* same message to both syslog and remote user */ 800 asprintf(&syserr, "connected from invalid port (%s)", serv); 801 fhosterr(ch_opts, syserr, syserr); 802 /* NOTREACHED */ 803 } 804 } 805 806 /* 807 * Handle fatal errors in chkhost. The first message will optionally be 808 * sent to syslog, the second one is sent to the connecting host. 809 * 810 * The idea is that the syslog message is meant for an administrator of a 811 * print server (the host receiving connections), while the usermsg is meant 812 * for a remote user who may or may not be clueful, and may or may not be 813 * doing something nefarious. Some remote users (eg, MS-Windows...) may not 814 * even see whatever message is sent, which is why there's the option to 815 * start 'lpd' with the connection-errors also sent to syslog. 816 * 817 * Given that hostnames can theoretically be fairly long (well, over 250 818 * bytes), it would probably be helpful to have the 'from_host' field at 819 * the end of any error messages which include that info. 820 * 821 * These are Fatal host-connection errors, so this routine does not return. 822 */ 823 static void 824 fhosterr(int ch_opts, char *sysmsg, char *usermsg) 825 { 826 827 /* 828 * If lpd was started up to print connection errors, then write 829 * the syslog message before the user message. 830 * And for many of the syslog messages, it is helpful to first 831 * write the from_host (if it is known) as a separate syslog 832 * message, since the hostname may be so long. 833 */ 834 if (ch_opts & LPD_LOGCONNERR) { 835 if (ch_opts & LPD_ADDFROMLINE) { 836 syslog(LOG_WARNING, "for connection from %s:", from_host); 837 } 838 syslog(LOG_WARNING, "%s", sysmsg); 839 } 840 841 /* 842 * Now send the error message to the remote host which is trying 843 * to make the connection. 844 */ 845 printf("%s [@%s]: %s\n", progname, local_host, usermsg); 846 fflush(stdout); 847 848 /* 849 * Add a minimal delay before exiting (and disconnecting from the 850 * sending-host). This is just in case that machine responds by 851 * INSTANTLY retrying (and instantly re-failing...). This may also 852 * give the other side more time to read the error message. 853 */ 854 sleep(2); /* a paranoid throttling measure */ 855 exit(1); 856 } 857 858 /* setup server socket for specified address family */ 859 /* if af is PF_UNSPEC more than one socket may be returned */ 860 /* the returned list is dynamically allocated, so caller needs to free it */ 861 static int * 862 socksetup(int af, int debuglvl) 863 { 864 struct addrinfo hints, *res, *r; 865 int error, maxs, *s, *socks; 866 const int on = 1; 867 868 memset(&hints, 0, sizeof(hints)); 869 hints.ai_flags = AI_PASSIVE; 870 hints.ai_family = af; 871 hints.ai_socktype = SOCK_STREAM; 872 error = getaddrinfo(NULL, "printer", &hints, &res); 873 if (error) { 874 syslog(LOG_ERR, "%s", gai_strerror(error)); 875 mcleanup(0); 876 } 877 878 /* Count max number of sockets we may open */ 879 for (maxs = 0, r = res; r; r = r->ai_next, maxs++) 880 ; 881 socks = malloc((maxs + 1) * sizeof(int)); 882 if (!socks) { 883 syslog(LOG_ERR, "couldn't allocate memory for sockets"); 884 mcleanup(0); 885 } 886 887 *socks = 0; /* num of sockets counter at start of array */ 888 s = socks + 1; 889 for (r = res; r; r = r->ai_next) { 890 *s = socket(r->ai_family, r->ai_socktype, r->ai_protocol); 891 if (*s < 0) { 892 syslog(LOG_DEBUG, "socket(): %m"); 893 continue; 894 } 895 if (setsockopt(*s, SOL_SOCKET, SO_REUSEADDR, &on, sizeof(on)) 896 < 0) { 897 syslog(LOG_ERR, "setsockopt(SO_REUSEADDR): %m"); 898 close(*s); 899 continue; 900 } 901 if (debuglvl) 902 if (setsockopt(*s, SOL_SOCKET, SO_DEBUG, &debuglvl, 903 sizeof(debuglvl)) < 0) { 904 syslog(LOG_ERR, "setsockopt (SO_DEBUG): %m"); 905 close(*s); 906 continue; 907 } 908 if (r->ai_family == AF_INET6) { 909 if (setsockopt(*s, IPPROTO_IPV6, IPV6_V6ONLY, 910 &on, sizeof(on)) < 0) { 911 syslog(LOG_ERR, 912 "setsockopt (IPV6_V6ONLY): %m"); 913 close(*s); 914 continue; 915 } 916 } 917 if (bind(*s, r->ai_addr, r->ai_addrlen) < 0) { 918 syslog(LOG_DEBUG, "bind(): %m"); 919 close(*s); 920 continue; 921 } 922 (*socks)++; 923 s++; 924 } 925 926 if (res) 927 freeaddrinfo(res); 928 929 if (*socks == 0) { 930 syslog(LOG_ERR, "Couldn't bind to any socket"); 931 free(socks); 932 mcleanup(0); 933 } 934 return(socks); 935 } 936 937 static void 938 usage(void) 939 { 940 #ifdef INET6 941 fprintf(stderr, "usage: lpd [-cdlsW46] [port#]\n"); 942 #else 943 fprintf(stderr, "usage: lpd [-cdlsW] [port#]\n"); 944 #endif 945 exit(EX_USAGE); 946 } 947