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
91int	lflag;				/* log requests flag */
92int	sflag;				/* no incoming port flag */
93int	Fflag;				/* run in foreground flag */
94int	from_remote;			/* from remote socket */
95
96int		 main(int argc, char **_argv);
97static void	 reapchild(int _signo);
98static void	 mcleanup(int _signo);
99static void	 doit(void);
100static void	 startup(void);
101static void	 chkhost(struct sockaddr *_f, int _ch_opts);
102static int	 ckqueue(struct printer *_pp);
103static void	 fhosterr(int _ch_opts, char *_sysmsg, char *_usermsg);
104static int	*socksetup(int _af, int _debuglvl);
105static void	 usage(void);
106
107/* XXX from libc/net/rcmd.c */
108extern int __ivaliduser_sa(FILE *, struct sockaddr *, socklen_t,
109				const char *, const char *);
110
111uid_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
117int
118main(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(07);
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
421static void
422reapchild(int signo __unused)
423{
424	int status;
425
426	while (wait3(&status, WNOHANG, 0) > 0)
427		;
428}
429
430static void
431mcleanup(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 */
449char	*user[MAXUSERS];	/* users to process */
450int	users;			/* # of users in user array */
451int	requ[MAXREQUESTS];	/* job number of spool entries */
452int	requests;		/* # of spool requests */
453char	*person;		/* name of person doing lprm */
454
455		 /* buffer to hold the client's machine-name */
456static char	 frombuf[MAXHOSTNAMELEN];
457char	cbuf[BUFSIZ];		/* command line buffer */
458const char	*cmdnames[] = {
459	"null",
460	"printjob",
461	"recvjob",
462	"displayq short",
463	"displayq long",
464	"rmjob"
465};
466
467static void
468doit(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 */
581static void
582startup(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 {
608next:
609			more = nextprinter(pp, &status);
610errloop:
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 */
622static int
623ckqueue(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 */
648static void
649chkhost(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");
751again:
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
773foundhost:
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 */
811static void
812fhosterr(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 */
849static int *
850socksetup(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
925static void
926usage(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