OpenBSD-4.6/usr.sbin/lpr/lpd/lpd.c
/* $OpenBSD: lpd.c,v 1.49 2008/05/26 06:30:35 otto Exp $ */
/* $NetBSD: lpd.c,v 1.33 2002/01/21 14:42:29 wiz Exp $ */
/*
* Copyright (c) 1983, 1993, 1994
* The Regents of the University of California. All rights reserved.
*
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#ifndef lint
static const char copyright[] =
"@(#) Copyright (c) 1983, 1993, 1994\n\
The Regents of the University of California. All rights reserved.\n";
#endif /* not lint */
#ifndef lint
#if 0
static const char sccsid[] = "@(#)lpd.c 8.7 (Berkeley) 5/10/95";
#else
static const char rcsid[] = "$OpenBSD: lpd.c,v 1.49 2008/05/26 06:30:35 otto Exp $";
#endif
#endif /* not lint */
/*
* lpd -- line printer daemon.
*
* Listen for a connection and perform the requested operation.
* Operations are:
* \1printer\n
* check the queue for jobs and print any found.
* \2printer\n
* receive a job from another machine and queue it.
* \3printer [users ...] [jobs ...]\n
* return the current state of the queue (short form).
* \4printer [users ...] [jobs ...]\n
* return the current state of the queue (long form).
* \5printer person [users ...] [jobs ...]\n
* remove jobs from the queue.
*
* Strategy to maintain protected spooling area:
* 1. Spooling area is writable only by root and the group daemon.
* 2. Files in spooling area are owned by user daemon, group daemon,
* and are mode 660.
* 3. lpd runs as root but spends most of its time with its effective
* uid and gid set to the uid/gid specified in the passwd entry for
* DEFUID (1, aka daemon).
* 4. lpr and lprm run setuid daemon and setgrp daemon. lpr opens
* files to be printed with its real uid/gid and writes to
* the spool dir with its effective uid/gid (i.e. daemon).
* lprm need to run as user daemon so it can kill lpd.
* 5. lpc and lpq run setgrp daemon.
*
* Users can't touch the spool w/o the help of one of the lp* programs.
*/
#include <sys/param.h>
#include <sys/wait.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <sys/un.h>
#include <sys/stat.h>
#include <sys/file.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <ctype.h>
#include <dirent.h>
#include <err.h>
#include <errno.h>
#include <fcntl.h>
#include <netdb.h>
#include <pwd.h>
#include <signal.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <syslog.h>
#include <unistd.h>
#include "lp.h"
#include "lp.local.h"
#include "pathnames.h"
#include "extern.h"
int lflag; /* log requests flag */
int rflag; /* allow 'of' for remote printers */
int sflag; /* secure (no inet) flag */
int from_remote; /* from remote socket */
char **blist; /* list of addresses to bind(2) to */
int blist_size;
int blist_addrs;
volatile sig_atomic_t child_count; /* number of kids forked */
static void reapchild(int);
static void mcleanup(int);
static void doit(void);
static void startup(void);
static void chkhost(struct sockaddr *);
static int ckqueue(char *);
static __dead void usage(void);
static int *socksetup(int, int, const char *);
extern int __ivaliduser_sa(FILE *, struct sockaddr *, socklen_t,
const char *, const char *);
/* unused, needed for lpc */
volatile sig_atomic_t gotintr;
int
main(int argc, char **argv)
{
fd_set defreadfds;
struct passwd *pw;
struct sockaddr_un un, fromunix;
struct sockaddr_storage frominet;
sigset_t mask, omask;
int lfd, i, f, funix, *finet;
int options, maxfd;
long l;
long child_max = 32; /* more than enough to hose the system */
struct servent *sp;
const char *port = "printer";
char *cp;
if (geteuid() != 0)
errx(1, "must run as root");
/*
* We want to run with euid of daemon most of the time.
*/
if ((pw = getpwuid(DEFUID)) == NULL)
errx(1, "daemon uid (%u) not in password file", DEFUID);
real_uid = pw->pw_uid;
real_gid = pw->pw_gid;
effective_uid = 0;
effective_gid = getegid();
PRIV_END; /* run as daemon for most things */
options = 0;
gethostname(host, sizeof(host));
while ((i = getopt(argc, argv, "b:dln:rsw:W")) != -1) {
switch (i) {
case 'b':
if (blist_addrs >= blist_size) {
if (blist == NULL) {
blist_size += sizeof(char *) * 4;
blist = malloc(blist_size);
}
else {
char **newblist;
int newblist_size = blist_size +
sizeof(char *) * 4;
newblist = realloc(blist, newblist_size);
if (newblist == NULL) {
free(blist);
blist_size = 0;
blist = NULL;
}
blist = newblist;
blist_size = newblist_size;
}
if (blist == NULL)
err(1, "cant allocate bind addr list");
}
blist[blist_addrs] = strdup(optarg);
if (blist[blist_addrs++] == NULL)
err(1, NULL);
break;
case 'd':
options |= SO_DEBUG;
break;
case 'l':
lflag++;
break;
case 'n':
child_max = strtol(optarg, &cp, 10);
if (*cp != '\0' || child_max < 0 || child_max > 1024)
errx(1, "invalid number of children: %s",
optarg);
break;
case 'r':
rflag++;
break;
case 's':
sflag++;
break;
case 'w':
l = strtol(optarg, &cp, 10);
if (*cp != '\0' || l < 0 || l >= INT_MAX)
errx(1, "wait time must be postive integer: %s",
optarg);
wait_time = (u_int)l;
if (wait_time < 30)
warnx("warning: wait time less than 30 seconds");
break;
case 'W': /* XXX deprecate */
break;
default:
usage();
break;
}
}
argc -= optind;
argv += optind;
switch (argc) {
case 1:
port = argv[0];
l = strtol(port, &cp, 10);
if (*cp != '\0' || l <= 0 || l > USHRT_MAX)
errx(1, "port # %s is invalid", port);
break;
case 0:
sp = getservbyname(port, "tcp");
if (sp == NULL)
errx(1, "%s/tcp: unknown service", port);
break;
default:
usage();
}
#ifndef DEBUG
/*
* Set up standard environment by detaching from the parent.
*/
daemon(0, 0);
#endif
openlog("lpd", LOG_PID, LOG_LPR);
syslog(LOG_INFO, "restarted");
(void)umask(0);
PRIV_START;
lfd = open(_PATH_MASTERLOCK, O_WRONLY|O_CREAT|O_EXLOCK|O_NONBLOCK, 0644);
PRIV_END;
if (lfd < 0) {
if (errno == EWOULDBLOCK) /* active daemon present */
exit(0);
syslog(LOG_ERR, "%s: %m", _PATH_MASTERLOCK);
exit(1);
}
ftruncate(lfd, 0);
/*
* write process id for others to know
*/
(void)snprintf(line, sizeof(line), "%u\n", getpid());
f = strlen(line);
if (write(lfd, line, f) != f) {
syslog(LOG_ERR, "%s: %m", _PATH_MASTERLOCK);
exit(1);
}
signal(SIGCHLD, reapchild);
/*
* Restart all the printers.
*/
startup();
PRIV_START;
(void)unlink(_PATH_SOCKETNAME);
PRIV_END;
funix = socket(AF_LOCAL, SOCK_STREAM, 0);
if (funix < 0) {
syslog(LOG_ERR, "socket: %m");
exit(1);
}
sigemptyset(&mask);
sigaddset(&mask, SIGHUP);
sigaddset(&mask, SIGINT);
sigaddset(&mask, SIGQUIT);
sigaddset(&mask, SIGTERM);
sigprocmask(SIG_BLOCK, &mask, &omask);
signal(SIGHUP, mcleanup);
signal(SIGINT, mcleanup);
signal(SIGQUIT, mcleanup);
signal(SIGTERM, mcleanup);
memset(&un, 0, sizeof(un));
un.sun_family = AF_LOCAL;
strlcpy(un.sun_path, _PATH_SOCKETNAME, sizeof(un.sun_path));
PRIV_START;
if (bind(funix, (struct sockaddr *)&un, SUN_LEN(&un)) < 0) {
syslog(LOG_ERR, "ubind: %m");
exit(1);
}
chmod(_PATH_SOCKETNAME, 0660);
chown(_PATH_SOCKETNAME, -1, real_gid);
PRIV_END;
(void)umask(0); /* XXX */
sigprocmask(SIG_SETMASK, &omask, NULL);
FD_ZERO(&defreadfds);
FD_SET(funix, &defreadfds);
listen(funix, 5);
if (!sflag || blist_addrs)
finet = socksetup(PF_UNSPEC, options, port);
else
finet = NULL; /* pretend we couldn't open TCP socket. */
if (blist != NULL) {
for (i = 0; i < blist_addrs; i++)
free(blist[i]);
free(blist);
}
maxfd = funix;
if (finet) {
for (i = 1; i <= *finet; i++) {
FD_SET(finet[i], &defreadfds);
listen(finet[i], 5);
if (finet[i] > maxfd)
maxfd = finet[i];
}
}
/*
* Main loop: accept, do a request, continue.
*/
memset(&frominet, 0, sizeof(frominet));
memset(&fromunix, 0, sizeof(fromunix));
for (;;) {
int domain, nfds, s;
socklen_t fromlen;
fd_set readfds;
short sleeptime = 10; /* overflows in about 2 hours */
while (child_max < child_count) {
syslog(LOG_WARNING,
"too many children, sleeping for %d seconds",
sleeptime);
sleep(sleeptime);
sleeptime <<= 1;
if (sleeptime < 0) {
syslog(LOG_CRIT, "sleeptime overflowed! help!");
sleeptime = 10;
}
}
FD_COPY(&defreadfds, &readfds);
nfds = select(maxfd + 1, &readfds, NULL, NULL, NULL);
if (nfds <= 0) {
if (nfds < 0 && errno != EINTR)
syslog(LOG_WARNING, "select: %m");
continue;
}
if (FD_ISSET(funix, &readfds)) {
domain = AF_LOCAL;
fromlen = sizeof(fromunix);
s = accept(funix,
(struct sockaddr *)&fromunix, &fromlen);
} else {
domain = AF_INET;
s = -1;
for (i = 1; i <= *finet; i++)
if (FD_ISSET(finet[i], &readfds)) {
in_port_t port;
fromlen = sizeof(frominet);
s = accept(finet[i],
(struct sockaddr *)&frominet,
&fromlen);
switch (frominet.ss_family) {
case AF_INET:
port = ((struct sockaddr_in *)
&frominet)->sin_port;
break;
case AF_INET6:
port = ((struct sockaddr_in6 *)
&frominet)->sin6_port;
break;
default:
port = 0;
}
/* check for ftp bounce attack */
if (port == htons(20)) {
close(s);
continue;
}
}
}
if (s < 0) {
if (errno != EINTR)
syslog(LOG_WARNING, "accept: %m");
continue;
}
switch (fork()) {
case 0:
signal(SIGCHLD, SIG_DFL);
signal(SIGHUP, SIG_IGN);
signal(SIGINT, SIG_IGN);
signal(SIGQUIT, SIG_IGN);
signal(SIGTERM, SIG_IGN);
(void)close(funix);
if (!sflag && finet)
for (i = 1; i <= *finet; i++)
(void)close(finet[i]);
if (s != STDOUT_FILENO) {
dup2(s, STDOUT_FILENO);
(void)close(s);
}
if (domain == AF_INET) {
/* for both AF_INET and AF_INET6 */
from_remote = 1;
chkhost((struct sockaddr *)&frominet);
} else
from_remote = 0;
doit();
exit(0);
case -1:
syslog(LOG_WARNING, "fork: %m, sleeping for 10 seconds...");
sleep(10);
continue;
default:
child_count++;
}
(void)close(s);
}
}
static void
reapchild(int signo)
{
int save_errno = errno;
int status;
while (waitpid((pid_t)-1, &status, WNOHANG) > 0)
child_count--;
errno = save_errno;
}
static void
mcleanup(int signo)
{
struct syslog_data sdata = SYSLOG_DATA_INIT;
if (lflag)
syslog_r(LOG_INFO, &sdata, "exiting");
PRIV_START;
unlink(_PATH_SOCKETNAME);
unlink(_PATH_MASTERLOCK);
_exit(0);
}
/*
* Stuff for handling job specifications
*/
char *user[MAXUSERS]; /* users to process */
int users; /* # of users in user array */
int requ[MAXREQUESTS]; /* job number of spool entries */
int requests; /* # of spool requests */
char *person; /* name of person doing lprm */
char fromb[NI_MAXHOST]; /* buffer for client's machine name */
char cbuf[BUFSIZ]; /* command line buffer */
char *cmdnames[] = {
"null",
"printjob",
"recvjob",
"displayq short",
"displayq long",
"rmjob"
};
static void
doit(void)
{
char *cp;
int n;
for (;;) {
cp = cbuf;
do {
if (cp >= &cbuf[sizeof(cbuf) - 1])
fatal("Command line too long");
if ((n = read(STDOUT_FILENO, cp, 1)) != 1) {
if (n < 0)
fatal("Lost connection");
return;
}
} while (*cp++ != '\n');
*--cp = '\0';
cp = cbuf;
if (lflag) {
if (*cp >= '\1' && *cp <= '\5') {
syslog(LOG_INFO, "%s requests %s %s",
from, cmdnames[(int)*cp], cp+1);
setproctitle("serving %s: %s %s", from,
cmdnames[(int)*cp], cp+1);
} else
syslog(LOG_INFO, "bad request (%d) from %s",
*cp, from);
}
switch (*cp++) {
case '\1': /* check the queue and print any jobs there */
printer = cp;
if (*printer == '\0')
printer = DEFLP;
printjob();
break;
case '\2': /* receive files to be queued */
if (!from_remote) {
syslog(LOG_INFO, "illegal request (%d)", *cp);
exit(1);
}
printer = cp;
if (*printer == '\0')
printer = DEFLP;
recvjob();
break;
case '\3': /* display the queue (short form) */
case '\4': /* display the queue (long form) */
printer = cp;
if (*printer == '\0')
printer = DEFLP;
while (*cp) {
if (*cp != ' ') {
cp++;
continue;
}
*cp++ = '\0';
while (isspace(*cp))
cp++;
if (*cp == '\0')
break;
if (isdigit(*cp)) {
if (requests >= MAXREQUESTS)
fatal("Too many requests");
requ[requests++] = atoi(cp);
} else {
if (users >= MAXUSERS)
fatal("Too many users");
user[users++] = cp;
}
}
displayq(cbuf[0] - '\3');
exit(0);
case '\5': /* remove a job from the queue */
if (!from_remote) {
syslog(LOG_INFO, "illegal request (%d)", *cp);
exit(1);
}
printer = cp;
if (*printer == '\0')
printer = DEFLP;
while (*cp && *cp != ' ')
cp++;
if (!*cp)
break;
*cp++ = '\0';
person = cp;
while (*cp) {
if (*cp != ' ') {
cp++;
continue;
}
*cp++ = '\0';
while (isspace(*cp))
cp++;
if (*cp == '\0')
break;
if (isdigit(*cp)) {
if (requests >= MAXREQUESTS)
fatal("Too many requests");
requ[requests++] = atoi(cp);
} else {
if (users >= MAXUSERS)
fatal("Too many users");
user[users++] = cp;
}
}
rmjob();
break;
}
fatal("Illegal service request");
}
}
/*
* Make a pass through the printcap database and start printing any
* files left from the last time the machine went down.
*/
static void
startup(void)
{
char *buf, *cp;
/*
* Restart the daemons.
*/
while (cgetnext(&buf, printcapdb) > 0) {
if (ckqueue(buf) <= 0) {
free(buf);
continue; /* no work to do for this printer */
}
for (cp = buf; *cp; cp++)
if (*cp == '|' || *cp == ':') {
*cp = '\0';
break;
}
if (lflag)
syslog(LOG_INFO, "work for %s", buf);
switch (fork()) {
case -1:
syslog(LOG_WARNING, "startup: cannot fork");
mcleanup(0);
/* NOTREACHED */
case 0:
printer = buf;
setproctitle("working on printer %s", printer);
cgetclose();
printjob();
/* NOTREACHED */
default:
child_count++;
free(buf);
}
}
}
/*
* Make sure there's some work to do before forking off a child
* XXX - could be common w/ lpq
*/
static int
ckqueue(char *cap)
{
struct dirent *d;
DIR *dirp;
char *spooldir;
if (cgetstr(cap, "sd", &spooldir) >= 0) {
dirp = opendir(spooldir);
free(spooldir);
} else
dirp = opendir(_PATH_DEFSPOOL);
if (dirp == NULL)
return (-1);
while ((d = readdir(dirp)) != NULL) {
if (d->d_name[0] == 'c' && d->d_name[1] == 'f') {
closedir(dirp);
return (1); /* found a cf file */
}
}
closedir(dirp);
return (0);
}
#define DUMMY ":nobody::"
/*
* Check to see if the from host has access to the line printer.
*/
static void
chkhost(struct sockaddr *f)
{
struct addrinfo hints, *res, *r;
FILE *hostf;
int first = 1;
int good = 0;
char host[NI_MAXHOST], ip[NI_MAXHOST];
char serv[NI_MAXSERV];
int error;
error = getnameinfo(f, f->sa_len, NULL, 0, serv, sizeof(serv),
NI_NUMERICSERV);
if (error)
fatal("Malformed from address");
/* Need real hostname for temporary filenames */
error = getnameinfo(f, f->sa_len, host, sizeof(host), NULL, 0,
NI_NAMEREQD);
if (error) {
error = getnameinfo(f, f->sa_len, host, sizeof(host), NULL, 0,
NI_NUMERICHOST);
if (error)
fatal("Host name for your address unknown");
else
fatal("Host name for your address (%s) unknown", host);
}
(void)strlcpy(fromb, host, sizeof(fromb));
from = fromb;
/* need address in stringform for comparison (no DNS lookup here) */
error = getnameinfo(f, f->sa_len, host, sizeof(host), NULL, 0,
NI_NUMERICHOST);
if (error)
fatal("Cannot print address");
/* Check for spoof, ala rlogind */
memset(&hints, 0, sizeof(hints));
hints.ai_family = PF_UNSPEC;
hints.ai_socktype = SOCK_DGRAM; /*dummy*/
error = getaddrinfo(fromb, NULL, &hints, &res);
if (error) {
fatal("hostname for your address (%s) unknown: %s", host,
gai_strerror(error));
}
for (good = 0, r = res; good == 0 && r; r = r->ai_next) {
error = getnameinfo(r->ai_addr, r->ai_addrlen, ip, sizeof(ip),
NULL, 0, NI_NUMERICHOST);
if (!error && !strcmp(host, ip))
good = 1;
}
if (res)
freeaddrinfo(res);
if (good == 0)
fatal("address for your hostname (%s) not matched", host);
setproctitle("serving %s", from);
PRIV_START;
hostf = fopen(_PATH_HOSTSEQUIV, "r");
PRIV_END;
again:
if (hostf) {
if (__ivaliduser_sa(hostf, f, f->sa_len, DUMMY, DUMMY) == 0) {
(void)fclose(hostf);
return;
}
(void)fclose(hostf);
}
if (first == 1) {
first = 0;
PRIV_START;
hostf = fopen(_PATH_HOSTSLPD, "r");
PRIV_END;
goto again;
}
fatal("Your host does not have line printer access");
/*NOTREACHED*/
}
static __dead void
usage(void)
{
extern char *__progname;
fprintf(stderr, "usage: %s [-dlrs] [-b bind-address] [-n maxchild] "
"[-w maxwait] [port]\n", __progname);
exit(1);
}
/*
* Setup server socket for specified address family.
* If af is PF_UNSPEC more than one socket may be returned.
* The returned list is dynamically allocated, so the caller needs to free it.
*/
int *
socksetup(int af, int options, const char *port)
{
struct addrinfo hints, *res, *r;
int error, maxs = 0, *s, *socks = NULL, *newsocks, blidx = 0;
const int on = 1;
do {
memset(&hints, 0, sizeof(hints));
hints.ai_flags = AI_PASSIVE;
hints.ai_family = af;
hints.ai_socktype = SOCK_STREAM;
error = getaddrinfo((blist_addrs == 0) ? NULL : blist[blidx],
port ? port : "printer", &hints, &res);
if (error) {
if (blist_addrs)
syslog(LOG_ERR, "%s: %s", blist[blidx],
gai_strerror(error));
else
syslog(LOG_ERR, "%s", gai_strerror(error));
mcleanup(0);
}
/* Count max number of sockets we may open */
for (r = res; r; r = r->ai_next, maxs++)
;
if (socks == NULL) {
socks = calloc(maxs + 1, sizeof(int));
if (socks)
*socks = 0; /* num of sockets ctr at start */
} else {
newsocks = realloc(socks, (maxs + 1) * sizeof(int));
if (newsocks)
socks = newsocks;
else {
free(socks);
socks = NULL;
}
}
if (!socks) {
syslog(LOG_ERR, "couldn't allocate memory for sockets");
mcleanup(0);
}
s = socks + *socks + 1;
for (r = res; r; r = r->ai_next) {
*s = socket(r->ai_family, r->ai_socktype,
r->ai_protocol);
if (*s < 0) {
syslog(LOG_DEBUG, "socket(): %m");
continue;
}
if (options & SO_DEBUG)
if (setsockopt(*s, SOL_SOCKET, SO_DEBUG,
&on, sizeof(on)) < 0) {
syslog(LOG_ERR,
"setsockopt (SO_DEBUG): %m");
close (*s);
continue;
}
PRIV_START;
error = bind(*s, r->ai_addr, r->ai_addrlen);
PRIV_END;
if (error < 0) {
syslog(LOG_DEBUG, "bind(): %m");
close (*s);
continue;
}
*socks = *socks + 1;
s++;
}
if (res)
freeaddrinfo(res);
} while (++blidx < blist_addrs);
if (socks == NULL || *socks == 0) {
syslog(LOG_ERR, "Couldn't bind to any socket");
if (socks != NULL)
free(socks);
mcleanup(0);
}
return(socks);
}