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/wait.h>
65 #include <sys/types.h>
66 #include <sys/socket.h>
67 #include <sys/un.h>
68 #include <sys/stat.h>
69 #include <sys/file.h>
70 #include <netinet/in.h>
71 #include <arpa/inet.h>
72
73 #include <netdb.h>
74 #include <unistd.h>
75 #include <syslog.h>
76 #include <signal.h>
77 #include <err.h>
78 #include <errno.h>
79 #include <fcntl.h>
80 #include <dirent.h>
81 #include <stdio.h>
82 #include <stdlib.h>
83 #include <string.h>
84 #include <sysexits.h>
85 #include <ctype.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 int ch_options, errs, f, funix, *finet, i, lfd, socket_debug;
121 fd_set defreadfds;
122 struct sockaddr_un un, fromunix;
123 struct sockaddr_storage frominet;
124 socklen_t fromlen;
125 sigset_t omask, nmask;
126 struct servent *sp, serv;
127 int inet_flag = 0, inet6_flag = 0;
128
129 euid = geteuid(); /* these shouldn't be different */
130 uid = getuid();
131
132 ch_options = 0;
133 socket_debug = 0;
134 gethostname(local_host, sizeof(local_host));
135
136 progname = "lpd";
137
138 if (euid != 0)
139 errx(EX_NOPERM,"must run as root");
140
141 errs = 0;
142 while ((i = getopt(argc, argv, "cdlpswFW46")) != -1)
143 switch (i) {
144 case 'c':
145 /* log all kinds of connection-errors to syslog */
146 ch_options |= LPD_LOGCONNERR;
147 break;
148 case 'd':
149 socket_debug++;
150 break;
151 case 'l':
152 lflag++;
153 break;
154 case 'p': /* letter initially used for -s */
155 /*
156 * This will probably be removed with 5.0-release.
157 */
158 /* FALLTHROUGH */
159 case 's': /* secure (no inet) */
160 sflag++;
161 break;
162 case 'w': /* netbsd uses -w for maxwait */
163 /*
164 * This will be removed after the release of 4.4, as
165 * it conflicts with -w in netbsd's lpd. For now it
166 * is just a warning, so we won't suddenly break lpd
167 * for anyone who is currently using the option.
168 */
169 syslog(LOG_WARNING,
170 "NOTE: the -w option has been renamed -W");
171 syslog(LOG_WARNING,
172 "NOTE: please change your lpd config to use -W");
173 /* FALLTHROUGH */
174 case 'F':
175 Fflag++;
176 break;
177 case 'W':
178 /* allow connections coming from a non-reserved port */
179 /* (done by some lpr-implementations for MS-Windows) */
180 ch_options |= LPD_NOPORTCHK;
181 break;
182 case '4':
183 family = PF_INET;
184 inet_flag++;
185 break;
186 case '6':
187 #ifdef INET6
188 family = PF_INET6;
189 inet6_flag++;
190 #else
191 errx(EX_USAGE, "lpd compiled sans INET6 (IPv6 support)");
192 #endif
193 break;
194 /*
195 * The following options are not in FreeBSD (yet?), but are
196 * listed here to "reserve" them, because the option-letters
197 * are used by either NetBSD or OpenBSD (as of July 2001).
198 */
199 case 'b': /* set bind-addr */
200 case 'n': /* set max num of children */
201 case 'r': /* allow 'of' for remote ptrs */
202 /* ...[not needed in freebsd] */
203 /* FALLTHROUGH */
204 default:
205 errs++;
206 }
207 if (inet_flag && inet6_flag)
208 family = PF_UNSPEC;
209 argc -= optind;
210 argv += optind;
211 if (errs)
212 usage();
213
214 if (argc == 1) {
215 if ((i = atoi(argv[0])) == 0)
216 usage();
217 if (i < 0 || i > USHRT_MAX)
218 errx(EX_USAGE, "port # %d is invalid", i);
219
220 serv.s_port = htons(i);
221 sp = &serv;
222 argc--;
223 } else {
224 sp = getservbyname("printer", "tcp");
225 if (sp == NULL)
226 errx(EX_OSFILE, "printer/tcp: unknown service");
227 }
228
229 if (argc != 0)
230 usage();
231
232 /*
233 * We run chkprintcap right away to catch any errors and blat them
234 * to stderr while we still have it open, rather than sending them
235 * to syslog and leaving the user wondering why lpd started and
236 * then stopped. There should probably be a command-line flag to
237 * ignore errors from chkprintcap.
238 */
239 {
240 pid_t pid;
241 int status;
242 pid = fork();
243 if (pid < 0) {
244 err(EX_OSERR, "cannot fork");
245 } else if (pid == 0) { /* child */
246 execl(_PATH_CHKPRINTCAP, _PATH_CHKPRINTCAP, (char *)0);
247 err(EX_OSERR, "cannot execute %s", _PATH_CHKPRINTCAP);
248 }
249 if (waitpid(pid, &status, 0) < 0) {
250 err(EX_OSERR, "cannot wait");
251 }
252 if (WIFEXITED(status) && WEXITSTATUS(status) != 0)
253 errx(EX_OSFILE, "%d errors in printcap file, exiting",
254 WEXITSTATUS(status));
255 }
256
257 #ifdef DEBUG
258 Fflag++;
259 #endif
260 /*
261 * Set up standard environment by detaching from the parent
262 * if -F not specified
263 */
264 if (Fflag == 0) {
265 daemon(0, 0);
266 }
267
268 openlog("lpd", LOG_PID, LOG_LPR);
269 syslog(LOG_INFO, "lpd startup: logging=%d%s%s", lflag,
270 socket_debug ? " dbg" : "", sflag ? " net-secure" : "");
271 (void) umask(0);
272 /*
273 * NB: This depends on O_NONBLOCK semantics doing the right thing;
274 * i.e., applying only to the O_EXLOCK and not to the rest of the
275 * open/creation. As of 1997-12-02, this is the case for commonly-
276 * used filesystems. There are other places in this code which
277 * make the same assumption.
278 */
279 lfd = open(_PATH_MASTERLOCK, O_WRONLY|O_CREAT|O_EXLOCK|O_NONBLOCK,
280 LOCK_FILE_MODE);
281 if (lfd < 0) {
282 if (errno == EWOULDBLOCK) /* active daemon present */
283 exit(0);
284 syslog(LOG_ERR, "%s: %m", _PATH_MASTERLOCK);
285 exit(1);
286 }
287 fcntl(lfd, F_SETFL, 0); /* turn off non-blocking mode */
288 ftruncate(lfd, 0);
289 /*
290 * write process id for others to know
291 */
292 sprintf(line, "%u\n", getpid());
293 f = strlen(line);
294 if (write(lfd, line, f) != f) {
295 syslog(LOG_ERR, "%s: %m", _PATH_MASTERLOCK);
296 exit(1);
297 }
298 signal(SIGCHLD, reapchild);
299 /*
300 * Restart all the printers.
301 */
302 startup();
303 (void) unlink(_PATH_SOCKETNAME);
304 funix = socket(AF_UNIX, SOCK_STREAM, 0);
305 if (funix < 0) {
306 syslog(LOG_ERR, "socket: %m");
307 exit(1);
308 }
309
310 sigemptyset(&nmask);
311 sigaddset(&nmask, SIGHUP);
312 sigaddset(&nmask, SIGINT);
313 sigaddset(&nmask, SIGQUIT);
314 sigaddset(&nmask, SIGTERM);
315 sigprocmask(SIG_BLOCK, &nmask, &omask);
316
317 (void) umask(077);
318 signal(SIGHUP, mcleanup);
319 signal(SIGINT, mcleanup);
320 signal(SIGQUIT, mcleanup);
321 signal(SIGTERM, mcleanup);
322 memset(&un, 0, sizeof(un));
323 un.sun_family = AF_UNIX;
324 strcpy(un.sun_path, _PATH_SOCKETNAME);
325 #ifndef SUN_LEN
326 #define SUN_LEN(unp) (strlen((unp)->sun_path) + 2)
327 #endif
328 if (bind(funix, (struct sockaddr *)&un, SUN_LEN(&un)) < 0) {
329 syslog(LOG_ERR, "ubind: %m");
330 exit(1);
331 }
332 (void) umask(0);
333 sigprocmask(SIG_SETMASK, &omask, (sigset_t *)0);
334 FD_ZERO(&defreadfds);
335 FD_SET(funix, &defreadfds);
336 listen(funix, 5);
337 if (sflag == 0) {
338 finet = socksetup(family, socket_debug);
339 } else
340 finet = NULL; /* pretend we couldn't open TCP socket. */
341 if (finet) {
342 for (i = 1; i <= *finet; i++) {
343 FD_SET(finet[i], &defreadfds);
344 listen(finet[i], 5);
345 }
346 }
347 /*
348 * Main loop: accept, do a request, continue.
349 */
350 memset(&frominet, 0, sizeof(frominet));
351 memset(&fromunix, 0, sizeof(fromunix));
352 if (lflag)
353 syslog(LOG_INFO, "lpd startup: ready to accept requests");
354 /*
355 * XXX - should be redone for multi-protocol
356 */
357 for (;;) {
358 int domain, nfds, s;
359 fd_set readfds;
360
361 FD_COPY(&defreadfds, &readfds);
362 nfds = select(20, &readfds, 0, 0, 0);
363 if (nfds <= 0) {
364 if (nfds < 0 && errno != EINTR)
365 syslog(LOG_WARNING, "select: %m");
366 continue;
367 }
368 domain = -1; /* avoid compile-time warning */
369 s = -1; /* avoid compile-time warning */
370 if (FD_ISSET(funix, &readfds)) {
371 domain = AF_UNIX, fromlen = sizeof(fromunix);
372 s = accept(funix,
373 (struct sockaddr *)&fromunix, &fromlen);
374 } else {
375 for (i = 1; i <= *finet; i++)
376 if (FD_ISSET(finet[i], &readfds)) {
377 domain = AF_INET;
378 fromlen = sizeof(frominet);
379 s = accept(finet[i],
380 (struct sockaddr *)&frominet,
381 &fromlen);
382 }
383 }
384 if (s < 0) {
385 if (errno != EINTR)
386 syslog(LOG_WARNING, "accept: %m");
387 continue;
388 }
389 if (fork() == 0) {
390 /*
391 * Note that printjob() also plays around with
392 * signal-handling routines, and may need to be
393 * changed when making changes to signal-handling.
394 */
395 signal(SIGCHLD, SIG_DFL);
396 signal(SIGHUP, SIG_IGN);
397 signal(SIGINT, SIG_IGN);
398 signal(SIGQUIT, SIG_IGN);
399 signal(SIGTERM, SIG_IGN);
400 (void) close(funix);
401 if (sflag == 0 && finet) {
402 for (i = 1; i <= *finet; i++)
403 (void)close(finet[i]);
404 }
405 dup2(s, STDOUT_FILENO);
406 (void) close(s);
407 if (domain == AF_INET) {
408 /* for both AF_INET and AF_INET6 */
409 from_remote = 1;
410 chkhost((struct sockaddr *)&frominet,
411 ch_options);
412 } else
413 from_remote = 0;
414 doit();
415 exit(0);
416 }
417 (void) close(s);
418 }
419 }
420
421 static void
reapchild(int signo __unused)422 reapchild(int signo __unused)
423 {
424 int status;
425
426 while (wait3(&status, WNOHANG, 0) > 0)
427 ;
428 }
429
430 static void
mcleanup(int signo)431 mcleanup(int signo)
432 {
433 /*
434 * XXX syslog(3) is not signal-safe.
435 */
436 if (lflag) {
437 if (signo)
438 syslog(LOG_INFO, "exiting on signal %d", signo);
439 else
440 syslog(LOG_INFO, "exiting");
441 }
442 unlink(_PATH_SOCKETNAME);
443 exit(0);
444 }
445
446 /*
447 * Stuff for handling job specifications
448 */
449 char *user[MAXUSERS]; /* users to process */
450 int users; /* # of users in user array */
451 int requ[MAXREQUESTS]; /* job number of spool entries */
452 int requests; /* # of spool requests */
453 char *person; /* name of person doing lprm */
454
455 /* buffer to hold the client's machine-name */
456 static char frombuf[MAXHOSTNAMELEN];
457 char cbuf[BUFSIZ]; /* command line buffer */
458 const char *cmdnames[] = {
459 "null",
460 "printjob",
461 "recvjob",
462 "displayq short",
463 "displayq long",
464 "rmjob"
465 };
466
467 static void
doit(void)468 doit(void)
469 {
470 char *cp, *printer;
471 int n;
472 int status;
473 struct printer myprinter, *pp = &myprinter;
474
475 init_printer(&myprinter);
476
477 for (;;) {
478 cp = cbuf;
479 do {
480 if (cp >= &cbuf[sizeof(cbuf) - 1])
481 fatal(0, "Command line too long");
482 if ((n = read(STDOUT_FILENO, cp, 1)) != 1) {
483 if (n < 0)
484 fatal(0, "Lost connection");
485 return;
486 }
487 } while (*cp++ != '\n');
488 *--cp = '\0';
489 cp = cbuf;
490 if (lflag) {
491 if (*cp >= '\1' && *cp <= '\5')
492 syslog(LOG_INFO, "%s requests %s %s",
493 from_host, cmdnames[(u_char)*cp], cp+1);
494 else
495 syslog(LOG_INFO, "bad request (%d) from %s",
496 *cp, from_host);
497 }
498 switch (*cp++) {
499 case CMD_CHECK_QUE: /* check the queue, print any jobs there */
500 startprinting(cp);
501 break;
502 case CMD_TAKE_THIS: /* receive files to be queued */
503 if (!from_remote) {
504 syslog(LOG_INFO, "illegal request (%d)", *cp);
505 exit(1);
506 }
507 recvjob(cp);
508 break;
509 case CMD_SHOWQ_SHORT: /* display the queue (short form) */
510 case CMD_SHOWQ_LONG: /* display the queue (long form) */
511 /* XXX - this all needs to be redone. */
512 printer = cp;
513 while (*cp) {
514 if (*cp != ' ') {
515 cp++;
516 continue;
517 }
518 *cp++ = '\0';
519 while (isspace(*cp))
520 cp++;
521 if (*cp == '\0')
522 break;
523 if (isdigit(*cp)) {
524 if (requests >= MAXREQUESTS)
525 fatal(0, "Too many requests");
526 requ[requests++] = atoi(cp);
527 } else {
528 if (users >= MAXUSERS)
529 fatal(0, "Too many users");
530 user[users++] = cp;
531 }
532 }
533 status = getprintcap(printer, pp);
534 if (status < 0)
535 fatal(pp, "%s", pcaperr(status));
536 displayq(pp, cbuf[0] == CMD_SHOWQ_LONG);
537 exit(0);
538 case CMD_RMJOB: /* remove a job from the queue */
539 if (!from_remote) {
540 syslog(LOG_INFO, "illegal request (%d)", *cp);
541 exit(1);
542 }
543 printer = cp;
544 while (*cp && *cp != ' ')
545 cp++;
546 if (!*cp)
547 break;
548 *cp++ = '\0';
549 person = cp;
550 while (*cp) {
551 if (*cp != ' ') {
552 cp++;
553 continue;
554 }
555 *cp++ = '\0';
556 while (isspace(*cp))
557 cp++;
558 if (*cp == '\0')
559 break;
560 if (isdigit(*cp)) {
561 if (requests >= MAXREQUESTS)
562 fatal(0, "Too many requests");
563 requ[requests++] = atoi(cp);
564 } else {
565 if (users >= MAXUSERS)
566 fatal(0, "Too many users");
567 user[users++] = cp;
568 }
569 }
570 rmjob(printer);
571 break;
572 }
573 fatal(0, "Illegal service request");
574 }
575 }
576
577 /*
578 * Make a pass through the printcap database and start printing any
579 * files left from the last time the machine went down.
580 */
581 static void
startup(void)582 startup(void)
583 {
584 int pid, status, more;
585 struct printer myprinter, *pp = &myprinter;
586
587 more = firstprinter(pp, &status);
588 if (status)
589 goto errloop;
590 while (more) {
591 if (ckqueue(pp) <= 0) {
592 goto next;
593 }
594 if (lflag)
595 syslog(LOG_INFO, "lpd startup: work for %s",
596 pp->printer);
597 if ((pid = fork()) < 0) {
598 syslog(LOG_WARNING, "lpd startup: cannot fork for %s",
599 pp->printer);
600 mcleanup(0);
601 }
602 if (pid == 0) {
603 lastprinter();
604 printjob(pp);
605 /* NOTREACHED */
606 }
607 do {
608 next:
609 more = nextprinter(pp, &status);
610 errloop:
611 if (status)
612 syslog(LOG_WARNING,
613 "lpd startup: printcap entry for %s has errors, skipping",
614 pp->printer ? pp->printer : "<noname?>");
615 } while (more && status);
616 }
617 }
618
619 /*
620 * Make sure there's some work to do before forking off a child
621 */
622 static int
ckqueue(struct printer * pp)623 ckqueue(struct printer *pp)
624 {
625 register struct dirent *d;
626 DIR *dirp;
627 char *spooldir;
628
629 spooldir = pp->spool_dir;
630 if ((dirp = opendir(spooldir)) == NULL)
631 return (-1);
632 while ((d = readdir(dirp)) != NULL) {
633 if (d->d_name[0] != 'c' || d->d_name[1] != 'f')
634 continue; /* daemon control files only */
635 closedir(dirp);
636 return (1); /* found something */
637 }
638 closedir(dirp);
639 return (0);
640 }
641
642 #define DUMMY ":nobody::"
643
644 /*
645 * Check to see if the host connecting to this host has access to any
646 * lpd services on this host.
647 */
648 static void
chkhost(struct sockaddr * f,int ch_opts)649 chkhost(struct sockaddr *f, int ch_opts)
650 {
651 struct addrinfo hints, *res, *r;
652 register FILE *hostf;
653 char hostbuf[NI_MAXHOST], ip[NI_MAXHOST];
654 char serv[NI_MAXSERV];
655 char *syserr, *usererr;
656 int error, errsav, fpass, good;
657
658 from_host = ".na.";
659
660 /* Need real hostname for temporary filenames */
661 error = getnameinfo(f, f->sa_len, hostbuf, sizeof(hostbuf), NULL, 0,
662 NI_NAMEREQD);
663 if (error) {
664 errsav = error;
665 error = getnameinfo(f, f->sa_len, hostbuf, sizeof(hostbuf),
666 NULL, 0, NI_NUMERICHOST);
667 if (error) {
668 asprintf(&syserr,
669 "can not determine hostname for remote host (%d,%d)",
670 errsav, error);
671 asprintf(&usererr,
672 "Host name for your address is not known");
673 fhosterr(ch_opts, syserr, usererr);
674 /* NOTREACHED */
675 }
676 asprintf(&syserr,
677 "Host name for remote host (%s) not known (%d)",
678 hostbuf, errsav);
679 asprintf(&usererr,
680 "Host name for your address (%s) is not known",
681 hostbuf);
682 fhosterr(ch_opts, syserr, usererr);
683 /* NOTREACHED */
684 }
685
686 strlcpy(frombuf, hostbuf, sizeof(frombuf));
687 from_host = frombuf;
688 ch_opts |= LPD_ADDFROMLINE;
689
690 /* Need address in stringform for comparison (no DNS lookup here) */
691 error = getnameinfo(f, f->sa_len, hostbuf, sizeof(hostbuf), NULL, 0,
692 NI_NUMERICHOST);
693 if (error) {
694 asprintf(&syserr, "Cannot print IP address (error %d)",
695 error);
696 asprintf(&usererr, "Cannot print IP address for your host");
697 fhosterr(ch_opts, syserr, usererr);
698 /* NOTREACHED */
699 }
700 from_ip = strdup(hostbuf);
701
702 /* Reject numeric addresses */
703 memset(&hints, 0, sizeof(hints));
704 hints.ai_family = family;
705 hints.ai_socktype = SOCK_DGRAM; /*dummy*/
706 hints.ai_flags = AI_PASSIVE | AI_NUMERICHOST;
707 if (getaddrinfo(from_host, NULL, &hints, &res) == 0) {
708 freeaddrinfo(res);
709 /* This syslog message already includes from_host */
710 ch_opts &= ~LPD_ADDFROMLINE;
711 asprintf(&syserr, "reverse lookup results in non-FQDN %s",
712 from_host);
713 /* same message to both syslog and remote user */
714 fhosterr(ch_opts, syserr, syserr);
715 /* NOTREACHED */
716 }
717
718 /* Check for spoof, ala rlogind */
719 memset(&hints, 0, sizeof(hints));
720 hints.ai_family = family;
721 hints.ai_socktype = SOCK_DGRAM; /*dummy*/
722 error = getaddrinfo(from_host, NULL, &hints, &res);
723 if (error) {
724 asprintf(&syserr, "dns lookup for address %s failed: %s",
725 from_ip, gai_strerror(error));
726 asprintf(&usererr, "hostname for your address (%s) unknown: %s",
727 from_ip, gai_strerror(error));
728 fhosterr(ch_opts, syserr, usererr);
729 /* NOTREACHED */
730 }
731 good = 0;
732 for (r = res; good == 0 && r; r = r->ai_next) {
733 error = getnameinfo(r->ai_addr, r->ai_addrlen, ip, sizeof(ip),
734 NULL, 0, NI_NUMERICHOST);
735 if (!error && !strcmp(from_ip, ip))
736 good = 1;
737 }
738 if (res)
739 freeaddrinfo(res);
740 if (good == 0) {
741 asprintf(&syserr, "address for remote host (%s) not matched",
742 from_ip);
743 asprintf(&usererr,
744 "address for your hostname (%s) not matched", from_ip);
745 fhosterr(ch_opts, syserr, usererr);
746 /* NOTREACHED */
747 }
748
749 fpass = 1;
750 hostf = fopen(_PATH_HOSTSEQUIV, "r");
751 again:
752 if (hostf) {
753 if (__ivaliduser_sa(hostf, f, f->sa_len, DUMMY, DUMMY) == 0) {
754 (void) fclose(hostf);
755 goto foundhost;
756 }
757 (void) fclose(hostf);
758 }
759 if (fpass == 1) {
760 fpass = 2;
761 hostf = fopen(_PATH_HOSTSLPD, "r");
762 goto again;
763 }
764 /* This syslog message already includes from_host */
765 ch_opts &= ~LPD_ADDFROMLINE;
766 asprintf(&syserr, "refused connection from %s, sip=%s", from_host,
767 from_ip);
768 asprintf(&usererr,
769 "Print-services are not available to your host (%s).", from_host);
770 fhosterr(ch_opts, syserr, usererr);
771 /* NOTREACHED */
772
773 foundhost:
774 if (ch_opts & LPD_NOPORTCHK)
775 return; /* skip the reserved-port check */
776
777 error = getnameinfo(f, f->sa_len, NULL, 0, serv, sizeof(serv),
778 NI_NUMERICSERV);
779 if (error) {
780 /* same message to both syslog and remote user */
781 asprintf(&syserr, "malformed from-address (%d)", error);
782 fhosterr(ch_opts, syserr, syserr);
783 /* NOTREACHED */
784 }
785
786 if (atoi(serv) >= IPPORT_RESERVED) {
787 /* same message to both syslog and remote user */
788 asprintf(&syserr, "connected from invalid port (%s)", serv);
789 fhosterr(ch_opts, syserr, syserr);
790 /* NOTREACHED */
791 }
792 }
793
794 /*
795 * Handle fatal errors in chkhost. The first message will optionally be
796 * sent to syslog, the second one is sent to the connecting host.
797 *
798 * The idea is that the syslog message is meant for an administrator of a
799 * print server (the host receiving connections), while the usermsg is meant
800 * for a remote user who may or may not be clueful, and may or may not be
801 * doing something nefarious. Some remote users (eg, MS-Windows...) may not
802 * even see whatever message is sent, which is why there's the option to
803 * start 'lpd' with the connection-errors also sent to syslog.
804 *
805 * Given that hostnames can theoretically be fairly long (well, over 250
806 * bytes), it would probably be helpful to have the 'from_host' field at
807 * the end of any error messages which include that info.
808 *
809 * These are Fatal host-connection errors, so this routine does not return.
810 */
811 static void
fhosterr(int ch_opts,char * sysmsg,char * usermsg)812 fhosterr(int ch_opts, char *sysmsg, char *usermsg)
813 {
814
815 /*
816 * If lpd was started up to print connection errors, then write
817 * the syslog message before the user message.
818 * And for many of the syslog messages, it is helpful to first
819 * write the from_host (if it is known) as a separate syslog
820 * message, since the hostname may be so long.
821 */
822 if (ch_opts & LPD_LOGCONNERR) {
823 if (ch_opts & LPD_ADDFROMLINE) {
824 syslog(LOG_WARNING, "for connection from %s:", from_host);
825 }
826 syslog(LOG_WARNING, "%s", sysmsg);
827 }
828
829 /*
830 * Now send the error message to the remote host which is trying
831 * to make the connection.
832 */
833 printf("%s [@%s]: %s\n", progname, local_host, usermsg);
834 fflush(stdout);
835
836 /*
837 * Add a minimal delay before exiting (and disconnecting from the
838 * sending-host). This is just in case that machine responds by
839 * INSTANTLY retrying (and instantly re-failing...). This may also
840 * give the other side more time to read the error message.
841 */
842 sleep(2); /* a paranoid throttling measure */
843 exit(1);
844 }
845
846 /* setup server socket for specified address family */
847 /* if af is PF_UNSPEC more than one socket may be returned */
848 /* the returned list is dynamically allocated, so caller needs to free it */
849 static int *
socksetup(int af,int debuglvl)850 socksetup(int af, int debuglvl)
851 {
852 struct addrinfo hints, *res, *r;
853 int error, maxs, *s, *socks;
854 const int on = 1;
855
856 memset(&hints, 0, sizeof(hints));
857 hints.ai_flags = AI_PASSIVE;
858 hints.ai_family = af;
859 hints.ai_socktype = SOCK_STREAM;
860 error = getaddrinfo(NULL, "printer", &hints, &res);
861 if (error) {
862 syslog(LOG_ERR, "%s", gai_strerror(error));
863 mcleanup(0);
864 }
865
866 /* Count max number of sockets we may open */
867 for (maxs = 0, r = res; r; r = r->ai_next, maxs++)
868 ;
869 socks = malloc((maxs + 1) * sizeof(int));
870 if (!socks) {
871 syslog(LOG_ERR, "couldn't allocate memory for sockets");
872 mcleanup(0);
873 }
874
875 *socks = 0; /* num of sockets counter at start of array */
876 s = socks + 1;
877 for (r = res; r; r = r->ai_next) {
878 *s = socket(r->ai_family, r->ai_socktype, r->ai_protocol);
879 if (*s < 0) {
880 syslog(LOG_DEBUG, "socket(): %m");
881 continue;
882 }
883 if (setsockopt(*s, SOL_SOCKET, SO_REUSEADDR, &on, sizeof(on))
884 < 0) {
885 syslog(LOG_ERR, "setsockopt(SO_REUSEADDR): %m");
886 close(*s);
887 continue;
888 }
889 if (debuglvl)
890 if (setsockopt(*s, SOL_SOCKET, SO_DEBUG, &debuglvl,
891 sizeof(debuglvl)) < 0) {
892 syslog(LOG_ERR, "setsockopt (SO_DEBUG): %m");
893 close(*s);
894 continue;
895 }
896 if (r->ai_family == AF_INET6) {
897 if (setsockopt(*s, IPPROTO_IPV6, IPV6_V6ONLY,
898 &on, sizeof(on)) < 0) {
899 syslog(LOG_ERR,
900 "setsockopt (IPV6_V6ONLY): %m");
901 close(*s);
902 continue;
903 }
904 }
905 if (bind(*s, r->ai_addr, r->ai_addrlen) < 0) {
906 syslog(LOG_DEBUG, "bind(): %m");
907 close(*s);
908 continue;
909 }
910 (*socks)++;
911 s++;
912 }
913
914 if (res)
915 freeaddrinfo(res);
916
917 if (*socks == 0) {
918 syslog(LOG_ERR, "Couldn't bind to any socket");
919 free(socks);
920 mcleanup(0);
921 }
922 return(socks);
923 }
924
925 static void
usage(void)926 usage(void)
927 {
928 #ifdef INET6
929 fprintf(stderr, "usage: lpd [-cdlsFW46] [port#]\n");
930 #else
931 fprintf(stderr, "usage: lpd [-cdlsFW] [port#]\n");
932 #endif
933 exit(EX_USAGE);
934 }
935