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