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 #include "lp.cdefs.h" /* A cross-platform version of <sys/cdefs.h> */
34 /*
35 * lpd -- line printer daemon.
36 *
37 * Listen for a connection and perform the requested operation.
38 * Operations are:
39 * \1printer\n
40 * check the queue for jobs and print any found.
41 * \2printer\n
42 * receive a job from another machine and queue it.
43 * \3printer [users ...] [jobs ...]\n
44 * return the current state of the queue (short form).
45 * \4printer [users ...] [jobs ...]\n
46 * return the current state of the queue (long form).
47 * \5printer person [users ...] [jobs ...]\n
48 * remove jobs from the queue.
49 *
50 * Strategy to maintain protected spooling area:
51 * 1. Spooling area is writable only by daemon and spooling group
52 * 2. lpr runs setuid root and setgrp spooling group; it uses
53 * root to access any file it wants (verifying things before
54 * with an access call) and group id to know how it should
55 * set up ownership of files in the spooling area.
56 * 3. Files in spooling area are owned by root, group spooling
57 * group, with mode 660.
58 * 4. lpd, lpq and lprm run setuid daemon and setgrp spooling group to
59 * access files and printer. Users can't get to anything
60 * w/o help of lpq and lprm programs.
61 */
62
63 #include <sys/param.h>
64 #include <sys/file.h>
65 #include <sys/socket.h>
66 #include <sys/stat.h>
67 #include <sys/un.h>
68 #include <sys/wait.h>
69
70 #include <netinet/in.h>
71 #include <arpa/inet.h>
72
73 #include <ctype.h>
74 #include <dirent.h>
75 #include <err.h>
76 #include <errno.h>
77 #include <fcntl.h>
78 #include <netdb.h>
79 #include <signal.h>
80 #include <stdio.h>
81 #include <stdlib.h>
82 #include <string.h>
83 #include <sysexits.h>
84 #include <syslog.h>
85 #include <unistd.h>
86 #include "lp.h"
87 #include "lp.local.h"
88 #include "pathnames.h"
89 #include "extern.h"
90
91 int lflag; /* log requests flag */
92 int sflag; /* no incoming port flag */
93 int Fflag; /* run in foreground flag */
94 int from_remote; /* from remote socket */
95
96 int main(int argc, char **_argv);
97 static void reapchild(int _signo);
98 static void mcleanup(int _signo);
99 static void doit(void);
100 static void startup(void);
101 static void chkhost(struct sockaddr *_f, int _ch_opts);
102 static int ckqueue(struct printer *_pp);
103 static void fhosterr(int _ch_opts, char *_sysmsg, char *_usermsg);
104 static int *socksetup(int _af, int _debuglvl);
105 static void usage(void);
106
107 /* XXX from libc/net/rcmd.c */
108 extern int __ivaliduser_sa(FILE *, struct sockaddr *, socklen_t,
109 const char *, const char *);
110
111 uid_t uid, euid;
112
113 #define LPD_NOPORTCHK 0001 /* skip reserved-port check */
114 #define LPD_LOGCONNERR 0002 /* (sys)log connection errors */
115 #define LPD_ADDFROMLINE 0004 /* just used for fhosterr() */
116
117 int
main(int argc,char ** argv)118 main(int argc, char **argv)
119 {
120 struct timeval tv = { .tv_sec = 120 };
121 int ch_options, errs, f, funix, *finet, i, lfd, socket_debug;
122 fd_set defreadfds;
123 struct sockaddr_un un, fromunix;
124 struct sockaddr_storage frominet;
125 socklen_t fromlen;
126 sigset_t omask, nmask;
127 struct servent *sp, serv;
128 int inet_flag = 0, inet6_flag = 0;
129
130 euid = geteuid(); /* these shouldn't be different */
131 uid = getuid();
132
133 ch_options = 0;
134 socket_debug = 0;
135 gethostname(local_host, sizeof(local_host));
136
137 progname = "lpd";
138
139 if (euid != 0)
140 errx(EX_NOPERM,"must run as root");
141
142 errs = 0;
143 while ((i = getopt(argc, argv, "cdlpst:wFW46")) != -1)
144 switch (i) {
145 case 'c':
146 /* log all kinds of connection-errors to syslog */
147 ch_options |= LPD_LOGCONNERR;
148 break;
149 case 'd':
150 socket_debug++;
151 break;
152 case 'l':
153 lflag++;
154 break;
155 case 'p': /* letter initially used for -s */
156 /*
157 * This will probably be removed with 5.0-release.
158 */
159 /* FALLTHROUGH */
160 case 's': /* secure (no inet) */
161 sflag++;
162 break;
163 case 't':
164 tv.tv_sec = atol(optarg);
165 break;
166 case 'w': /* netbsd uses -w for maxwait */
167 /*
168 * This will be removed after the release of 4.4, as
169 * it conflicts with -w in netbsd's lpd. For now it
170 * is just a warning, so we won't suddenly break lpd
171 * for anyone who is currently using the option.
172 */
173 syslog(LOG_WARNING,
174 "NOTE: the -w option has been renamed -W");
175 syslog(LOG_WARNING,
176 "NOTE: please change your lpd config to use -W");
177 /* FALLTHROUGH */
178 case 'F':
179 Fflag++;
180 break;
181 case 'W':
182 /* allow connections coming from a non-reserved port */
183 /* (done by some lpr-implementations for MS-Windows) */
184 ch_options |= LPD_NOPORTCHK;
185 break;
186 case '4':
187 family = PF_INET;
188 inet_flag++;
189 break;
190 case '6':
191 #ifdef INET6
192 family = PF_INET6;
193 inet6_flag++;
194 #else
195 errx(EX_USAGE, "lpd compiled sans INET6 (IPv6 support)");
196 #endif
197 break;
198 /*
199 * The following options are not in FreeBSD (yet?), but are
200 * listed here to "reserve" them, because the option-letters
201 * are used by either NetBSD or OpenBSD (as of July 2001).
202 */
203 case 'b': /* set bind-addr */
204 case 'n': /* set max num of children */
205 case 'r': /* allow 'of' for remote ptrs */
206 /* ...[not needed in freebsd] */
207 /* FALLTHROUGH */
208 default:
209 errs++;
210 }
211 if (inet_flag && inet6_flag)
212 family = PF_UNSPEC;
213 argc -= optind;
214 argv += optind;
215 if (errs)
216 usage();
217
218 if (argc == 1) {
219 if ((i = atoi(argv[0])) == 0)
220 usage();
221 if (i < 0 || i > USHRT_MAX)
222 errx(EX_USAGE, "port # %d is invalid", i);
223
224 serv.s_port = htons(i);
225 sp = &serv;
226 argc--;
227 } else {
228 sp = getservbyname("printer", "tcp");
229 if (sp == NULL)
230 errx(EX_OSFILE, "printer/tcp: unknown service");
231 }
232
233 if (argc != 0)
234 usage();
235
236 /*
237 * We run chkprintcap right away to catch any errors and blat them
238 * to stderr while we still have it open, rather than sending them
239 * to syslog and leaving the user wondering why lpd started and
240 * then stopped. There should probably be a command-line flag to
241 * ignore errors from chkprintcap.
242 */
243 {
244 pid_t pid;
245 int status;
246 pid = fork();
247 if (pid < 0) {
248 err(EX_OSERR, "cannot fork");
249 } else if (pid == 0) { /* child */
250 execl(_PATH_CHKPRINTCAP, _PATH_CHKPRINTCAP, (char *)0);
251 err(EX_OSERR, "cannot execute %s", _PATH_CHKPRINTCAP);
252 }
253 if (waitpid(pid, &status, 0) < 0) {
254 err(EX_OSERR, "cannot wait");
255 }
256 if (WIFEXITED(status) && WEXITSTATUS(status) != 0)
257 errx(EX_OSFILE, "%d errors in printcap file, exiting",
258 WEXITSTATUS(status));
259 }
260
261 #ifdef DEBUG
262 Fflag++;
263 #endif
264 /*
265 * Set up standard environment by detaching from the parent
266 * if -F not specified
267 */
268 if (Fflag == 0) {
269 daemon(0, 0);
270 }
271
272 openlog("lpd", LOG_PID, LOG_LPR);
273 syslog(LOG_INFO, "lpd startup: logging=%d%s%s", lflag,
274 socket_debug ? " dbg" : "", sflag ? " net-secure" : "");
275 (void) umask(0);
276 /*
277 * NB: This depends on O_NONBLOCK semantics doing the right thing;
278 * i.e., applying only to the O_EXLOCK and not to the rest of the
279 * open/creation. As of 1997-12-02, this is the case for commonly-
280 * used filesystems. There are other places in this code which
281 * make the same assumption.
282 */
283 lfd = open(_PATH_MASTERLOCK, O_WRONLY|O_CREAT|O_EXLOCK|O_NONBLOCK,
284 LOCK_FILE_MODE);
285 if (lfd < 0) {
286 if (errno == EWOULDBLOCK) /* active daemon present */
287 exit(0);
288 syslog(LOG_ERR, "%s: %m", _PATH_MASTERLOCK);
289 exit(1);
290 }
291 fcntl(lfd, F_SETFL, 0); /* turn off non-blocking mode */
292 ftruncate(lfd, 0);
293 /*
294 * write process id for others to know
295 */
296 sprintf(line, "%u\n", getpid());
297 f = strlen(line);
298 if (write(lfd, line, f) != f) {
299 syslog(LOG_ERR, "%s: %m", _PATH_MASTERLOCK);
300 exit(1);
301 }
302 signal(SIGCHLD, reapchild);
303 /*
304 * Restart all the printers.
305 */
306 startup();
307 (void) unlink(_PATH_SOCKETNAME);
308 funix = socket(AF_UNIX, SOCK_STREAM, 0);
309 if (funix < 0) {
310 syslog(LOG_ERR, "socket: %m");
311 exit(1);
312 }
313
314 sigemptyset(&nmask);
315 sigaddset(&nmask, SIGHUP);
316 sigaddset(&nmask, SIGINT);
317 sigaddset(&nmask, SIGQUIT);
318 sigaddset(&nmask, SIGTERM);
319 sigprocmask(SIG_BLOCK, &nmask, &omask);
320
321 (void) umask(077);
322 signal(SIGHUP, mcleanup);
323 signal(SIGINT, mcleanup);
324 signal(SIGQUIT, mcleanup);
325 signal(SIGTERM, mcleanup);
326 memset(&un, 0, sizeof(un));
327 un.sun_family = AF_UNIX;
328 strcpy(un.sun_path, _PATH_SOCKETNAME);
329 #ifndef SUN_LEN
330 #define SUN_LEN(unp) (strlen((unp)->sun_path) + 2)
331 #endif
332 if (bind(funix, (struct sockaddr *)&un, SUN_LEN(&un)) < 0) {
333 syslog(LOG_ERR, "ubind: %m");
334 exit(1);
335 }
336 (void) umask(0);
337 sigprocmask(SIG_SETMASK, &omask, (sigset_t *)0);
338 FD_ZERO(&defreadfds);
339 FD_SET(funix, &defreadfds);
340 listen(funix, 5);
341 if (sflag == 0) {
342 finet = socksetup(family, socket_debug);
343 } else
344 finet = NULL; /* pretend we couldn't open TCP socket. */
345 if (finet) {
346 for (i = 1; i <= *finet; i++) {
347 FD_SET(finet[i], &defreadfds);
348 listen(finet[i], 5);
349 }
350 }
351 /*
352 * Main loop: accept, do a request, continue.
353 */
354 memset(&frominet, 0, sizeof(frominet));
355 memset(&fromunix, 0, sizeof(fromunix));
356 if (lflag)
357 syslog(LOG_INFO, "lpd startup: ready to accept requests");
358 /*
359 * XXX - should be redone for multi-protocol
360 */
361 for (;;) {
362 int domain, nfds, s;
363 fd_set readfds;
364
365 FD_COPY(&defreadfds, &readfds);
366 nfds = select(20, &readfds, 0, 0, 0);
367 if (nfds <= 0) {
368 if (nfds < 0 && errno != EINTR)
369 syslog(LOG_WARNING, "select: %m");
370 continue;
371 }
372 domain = -1; /* avoid compile-time warning */
373 s = -1; /* avoid compile-time warning */
374 if (FD_ISSET(funix, &readfds)) {
375 domain = AF_UNIX, fromlen = sizeof(fromunix);
376 s = accept(funix,
377 (struct sockaddr *)&fromunix, &fromlen);
378 } else {
379 for (i = 1; i <= *finet; i++)
380 if (FD_ISSET(finet[i], &readfds)) {
381 domain = AF_INET;
382 fromlen = sizeof(frominet);
383 s = accept(finet[i],
384 (struct sockaddr *)&frominet,
385 &fromlen);
386 }
387 }
388 if (s < 0) {
389 if (errno != EINTR)
390 syslog(LOG_WARNING, "accept: %m");
391 continue;
392 }
393 if (tv.tv_sec > 0) {
394 (void) setsockopt(s, SOL_SOCKET, SO_RCVTIMEO, &tv,
395 sizeof(tv));
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
reapchild(int signo __unused)430 reapchild(int signo __unused)
431 {
432 int status;
433
434 while (wait3(&status, WNOHANG, 0) > 0)
435 ;
436 }
437
438 static void
mcleanup(int signo)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
doit(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
startup(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
ckqueue(struct printer * pp)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
chkhost(struct sockaddr * f,int ch_opts)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;
665
666 from_host = ".na.";
667
668 /* Need real hostname for temporary filenames */
669 error = getnameinfo(f, f->sa_len, hostbuf, sizeof(hostbuf), NULL, 0,
670 NI_NAMEREQD);
671 if (error) {
672 errsav = error;
673 error = getnameinfo(f, f->sa_len, hostbuf, sizeof(hostbuf),
674 NULL, 0, NI_NUMERICHOST);
675 if (error) {
676 asprintf(&syserr,
677 "can not determine hostname for remote host (%d,%d)",
678 errsav, error);
679 asprintf(&usererr,
680 "Host name for your address is not known");
681 fhosterr(ch_opts, syserr, usererr);
682 /* NOTREACHED */
683 }
684 asprintf(&syserr,
685 "Host name for remote host (%s) not known (%d)",
686 hostbuf, errsav);
687 asprintf(&usererr,
688 "Host name for your address (%s) is not known",
689 hostbuf);
690 fhosterr(ch_opts, syserr, usererr);
691 /* NOTREACHED */
692 }
693
694 strlcpy(frombuf, hostbuf, sizeof(frombuf));
695 from_host = frombuf;
696 ch_opts |= LPD_ADDFROMLINE;
697
698 /* Need address in stringform for comparison (no DNS lookup here) */
699 error = getnameinfo(f, f->sa_len, hostbuf, sizeof(hostbuf), NULL, 0,
700 NI_NUMERICHOST);
701 if (error) {
702 asprintf(&syserr, "Cannot print IP address (error %d)",
703 error);
704 asprintf(&usererr, "Cannot print IP address for your host");
705 fhosterr(ch_opts, syserr, usererr);
706 /* NOTREACHED */
707 }
708 from_ip = strdup(hostbuf);
709
710 /* Reject numeric addresses */
711 memset(&hints, 0, sizeof(hints));
712 hints.ai_family = family;
713 hints.ai_socktype = SOCK_DGRAM; /*dummy*/
714 hints.ai_flags = AI_PASSIVE | AI_NUMERICHOST;
715 if (getaddrinfo(from_host, NULL, &hints, &res) == 0) {
716 freeaddrinfo(res);
717 /* This syslog message already includes from_host */
718 ch_opts &= ~LPD_ADDFROMLINE;
719 asprintf(&syserr, "reverse lookup results in non-FQDN %s",
720 from_host);
721 /* same message to both syslog and remote user */
722 fhosterr(ch_opts, syserr, syserr);
723 /* NOTREACHED */
724 }
725
726 /* Check for spoof, ala rlogind */
727 memset(&hints, 0, sizeof(hints));
728 hints.ai_family = family;
729 hints.ai_socktype = SOCK_DGRAM; /*dummy*/
730 error = getaddrinfo(from_host, NULL, &hints, &res);
731 if (error) {
732 asprintf(&syserr, "dns lookup for address %s failed: %s",
733 from_ip, gai_strerror(error));
734 asprintf(&usererr, "hostname for your address (%s) unknown: %s",
735 from_ip, gai_strerror(error));
736 fhosterr(ch_opts, syserr, usererr);
737 /* NOTREACHED */
738 }
739 good = 0;
740 for (r = res; good == 0 && r; r = r->ai_next) {
741 error = getnameinfo(r->ai_addr, r->ai_addrlen, ip, sizeof(ip),
742 NULL, 0, NI_NUMERICHOST);
743 if (!error && !strcmp(from_ip, ip))
744 good = 1;
745 }
746 if (res)
747 freeaddrinfo(res);
748 if (good == 0) {
749 asprintf(&syserr, "address for remote host (%s) not matched",
750 from_ip);
751 asprintf(&usererr,
752 "address for your hostname (%s) not matched", from_ip);
753 fhosterr(ch_opts, syserr, usererr);
754 /* NOTREACHED */
755 }
756
757 fpass = 1;
758 hostf = fopen(_PATH_HOSTSEQUIV, "r");
759 again:
760 if (hostf) {
761 if (__ivaliduser_sa(hostf, f, f->sa_len, DUMMY, DUMMY) == 0) {
762 (void) fclose(hostf);
763 goto foundhost;
764 }
765 (void) fclose(hostf);
766 }
767 if (fpass == 1) {
768 fpass = 2;
769 hostf = fopen(_PATH_HOSTSLPD, "r");
770 goto again;
771 }
772 /* This syslog message already includes from_host */
773 ch_opts &= ~LPD_ADDFROMLINE;
774 asprintf(&syserr, "refused connection from %s, sip=%s", from_host,
775 from_ip);
776 asprintf(&usererr,
777 "Print-services are not available to your host (%s).", from_host);
778 fhosterr(ch_opts, syserr, usererr);
779 /* NOTREACHED */
780
781 foundhost:
782 if (ch_opts & LPD_NOPORTCHK)
783 return; /* skip the reserved-port check */
784
785 error = getnameinfo(f, f->sa_len, NULL, 0, serv, sizeof(serv),
786 NI_NUMERICSERV);
787 if (error) {
788 /* same message to both syslog and remote user */
789 asprintf(&syserr, "malformed from-address (%d)", error);
790 fhosterr(ch_opts, syserr, syserr);
791 /* NOTREACHED */
792 }
793
794 if (atoi(serv) >= IPPORT_RESERVED) {
795 /* same message to both syslog and remote user */
796 asprintf(&syserr, "connected from invalid port (%s)", serv);
797 fhosterr(ch_opts, syserr, syserr);
798 /* NOTREACHED */
799 }
800 }
801
802 /*
803 * Handle fatal errors in chkhost. The first message will optionally be
804 * sent to syslog, the second one is sent to the connecting host.
805 *
806 * The idea is that the syslog message is meant for an administrator of a
807 * print server (the host receiving connections), while the usermsg is meant
808 * for a remote user who may or may not be clueful, and may or may not be
809 * doing something nefarious. Some remote users (eg, MS-Windows...) may not
810 * even see whatever message is sent, which is why there's the option to
811 * start 'lpd' with the connection-errors also sent to syslog.
812 *
813 * Given that hostnames can theoretically be fairly long (well, over 250
814 * bytes), it would probably be helpful to have the 'from_host' field at
815 * the end of any error messages which include that info.
816 *
817 * These are Fatal host-connection errors, so this routine does not return.
818 */
819 static void
fhosterr(int ch_opts,char * sysmsg,char * usermsg)820 fhosterr(int ch_opts, char *sysmsg, char *usermsg)
821 {
822
823 /*
824 * If lpd was started up to print connection errors, then write
825 * the syslog message before the user message.
826 * And for many of the syslog messages, it is helpful to first
827 * write the from_host (if it is known) as a separate syslog
828 * message, since the hostname may be so long.
829 */
830 if (ch_opts & LPD_LOGCONNERR) {
831 if (ch_opts & LPD_ADDFROMLINE) {
832 syslog(LOG_WARNING, "for connection from %s:", from_host);
833 }
834 syslog(LOG_WARNING, "%s", sysmsg);
835 }
836
837 /*
838 * Now send the error message to the remote host which is trying
839 * to make the connection.
840 */
841 printf("%s [@%s]: %s\n", progname, local_host, usermsg);
842 fflush(stdout);
843
844 /*
845 * Add a minimal delay before exiting (and disconnecting from the
846 * sending-host). This is just in case that machine responds by
847 * INSTANTLY retrying (and instantly re-failing...). This may also
848 * give the other side more time to read the error message.
849 */
850 sleep(2); /* a paranoid throttling measure */
851 exit(1);
852 }
853
854 /* setup server socket for specified address family */
855 /* if af is PF_UNSPEC more than one socket may be returned */
856 /* the returned list is dynamically allocated, so caller needs to free it */
857 static int *
socksetup(int af,int debuglvl)858 socksetup(int af, int debuglvl)
859 {
860 struct addrinfo hints, *res, *r;
861 int error, maxs, *s, *socks;
862 const int on = 1;
863
864 memset(&hints, 0, sizeof(hints));
865 hints.ai_flags = AI_PASSIVE;
866 hints.ai_family = af;
867 hints.ai_socktype = SOCK_STREAM;
868 error = getaddrinfo(NULL, "printer", &hints, &res);
869 if (error) {
870 syslog(LOG_ERR, "%s", gai_strerror(error));
871 mcleanup(0);
872 }
873
874 /* Count max number of sockets we may open */
875 for (maxs = 0, r = res; r; r = r->ai_next, maxs++)
876 ;
877 socks = malloc((maxs + 1) * sizeof(int));
878 if (!socks) {
879 syslog(LOG_ERR, "couldn't allocate memory for sockets");
880 mcleanup(0);
881 }
882
883 *socks = 0; /* num of sockets counter at start of array */
884 s = socks + 1;
885 for (r = res; r; r = r->ai_next) {
886 *s = socket(r->ai_family, r->ai_socktype, r->ai_protocol);
887 if (*s < 0) {
888 syslog(LOG_DEBUG, "socket(): %m");
889 continue;
890 }
891 if (setsockopt(*s, SOL_SOCKET, SO_REUSEADDR, &on, sizeof(on))
892 < 0) {
893 syslog(LOG_ERR, "setsockopt(SO_REUSEADDR): %m");
894 close(*s);
895 continue;
896 }
897 if (debuglvl)
898 if (setsockopt(*s, SOL_SOCKET, SO_DEBUG, &debuglvl,
899 sizeof(debuglvl)) < 0) {
900 syslog(LOG_ERR, "setsockopt (SO_DEBUG): %m");
901 close(*s);
902 continue;
903 }
904 if (r->ai_family == AF_INET6) {
905 if (setsockopt(*s, IPPROTO_IPV6, IPV6_V6ONLY,
906 &on, sizeof(on)) < 0) {
907 syslog(LOG_ERR,
908 "setsockopt (IPV6_V6ONLY): %m");
909 close(*s);
910 continue;
911 }
912 }
913 if (bind(*s, r->ai_addr, r->ai_addrlen) < 0) {
914 syslog(LOG_DEBUG, "bind(): %m");
915 close(*s);
916 continue;
917 }
918 (*socks)++;
919 s++;
920 }
921
922 if (res)
923 freeaddrinfo(res);
924
925 if (*socks == 0) {
926 syslog(LOG_ERR, "Couldn't bind to any socket");
927 free(socks);
928 mcleanup(0);
929 }
930 return(socks);
931 }
932
933 static void
usage(void)934 usage(void)
935 {
936 #ifdef INET6
937 fprintf(stderr, "usage: lpd [-cdlsFW46] [port#]\n");
938 #else
939 fprintf(stderr, "usage: lpd [-cdlsFW] [port#]\n");
940 #endif
941 exit(EX_USAGE);
942 }
943