freebsd-nq/usr.sbin/daemon/daemon.c
Tom Rhodes 12d7249e24 Add support for dropping privileges to a specified user and/or group.
PR:		108523
Submitted by:	Dmitri Alenitchev <dmitri@dworlds.ru> (original version)
Reviewed by:	mpp (first reply to PR)
2007-03-09 09:33:19 +00:00

160 lines
4.0 KiB
C

/*-
* Copyright (c) 1999 Berkeley Software Design, Inc. 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. Berkeley Software Design Inc's name may not be used to endorse or
* promote products derived from this software without specific prior
* written permission.
*
* THIS SOFTWARE IS PROVIDED BY BERKELEY SOFTWARE DESIGN INC ``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 BERKELEY SOFTWARE DESIGN INC 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.
*
* From BSDI: daemon.c,v 1.2 1996/08/15 01:11:09 jch Exp
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include <sys/param.h>
#include <err.h>
#include <errno.h>
#include <pwd.h>
#include <grp.h>
#include <libutil.h>
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
static void restrict_process(const char *, const char *);
static void usage(void);
int
main(int argc, char *argv[])
{
struct pidfh *pfh;
int ch, nochdir, noclose, errcode;
const char *pidfile, *user, *group;
pid_t otherpid;
nochdir = noclose = 1;
pidfile = user = group = NULL;
while ((ch = getopt(argc, argv, "-cfg:p:u:")) != -1) {
switch (ch) {
case 'c':
nochdir = 0;
break;
case 'f':
noclose = 0;
break;
case 'u':
user = optarg;
break;
case 'g':
group = optarg;
break;
case 'p':
pidfile = optarg;
break;
default:
usage();
}
}
argc -= optind;
argv += optind;
if (argc == 0)
usage();
if (user || group) {
if (getuid() != 0)
errx(1, "only root user is allowed to chroot "
"and change UID/GID");
restrict_process(user, group);
}
/*
* Try to open the pidfile before calling daemon(3),
* to be able to report the error intelligently
*/
if (pidfile) {
pfh = pidfile_open(pidfile, 0600, &otherpid);
if (pfh == NULL) {
if (errno == EEXIST) {
errx(3, "process already running, pid: %d",
otherpid);
}
err(2, "pidfile ``%s''", pidfile);
}
}
if (daemon(nochdir, noclose) == -1)
err(1, NULL);
/* Now that we are the child, write out the pid */
if (pidfile)
pidfile_write(pfh);
execvp(argv[0], argv);
/*
* execvp() failed -- unlink pidfile if any, and
* report the error
*/
errcode = errno; /* Preserve errcode -- unlink may reset it */
if (pidfile)
pidfile_remove(pfh);
/* The child is now running, so the exit status doesn't matter. */
errc(1, errcode, "%s", argv[0]);
}
static void
restrict_process(const char *user, const char *group)
{
struct group *gr = NULL;
struct passwd *pw = NULL;
errno = 0;
if (group != NULL) {
if (initgroups(user, gr->gr_gid) == -1)
errx(1, "User not in group list");
if ((gr = getgrnam(group)) == NULL)
errx(1, "Group %s does not exist", group);
if (setgid(gr->gr_gid) == -1)
err(1, "%s", group);
}
if (user != NULL) {
if ((pw = getpwnam(user)) == NULL)
errx(1, "User %s does not exist", user);
if (setuid(pw->pw_uid) == -1)
err(1, "%s", user);
}
}
static void
usage(void)
{
(void)fprintf(stderr,
"usage: daemon [-cf] [-g group] [-p pidfile] [-u user] command "
"arguments ...\n");
exit(1);
}