shadow/libmisc/setugid.c

/*
 * Copyright (c) 1989 - 1994, Julianne Frances Haugh
 * Copyright (c) 1996 - 1998, Marek Michałkiewicz
 * Copyright (c) 2003 - 2005, Tomasz Kłoczko
 * Copyright (c) 2008       , Nicolas François
 * 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. The name of the copyright holders or contributors may not be used to
 *    endorse or promote products derived from this software without
 *    specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS 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 COPYRIGHT
 * HOLDERS 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.
 */

/*
 * Separated from setup.c.  --marekm
 */

#include <config.h>

#ident "$Id$"

#include <stdio.h>
#include <grp.h>
#include <errno.h>
#include "prototypes.h"
#include "defines.h"
#include <pwd.h>
#include "getdef.h"
/*
 * setup_uid_gid() split in two functions for PAM support -
 * pam_setcred() needs to be called after initgroups(), but
 * before setuid().
 */
int setup_groups (const struct passwd *info)
{
	/*
	 * Set the real group ID to the primary group ID in the password
	 * file.
	 */
	if (setgid (info->pw_gid) == -1) {
		int err = errno;
		perror ("setgid");
		SYSLOG ((LOG_ERR, "bad group ID `%d' for user `%s': %s\n",
		         info->pw_gid, info->pw_name, strerror (err)));
		closelog ();
		return -1;
	}
#ifdef HAVE_INITGROUPS
	/*
	 * For systems which support multiple concurrent groups, go get
	 * the group set from the /etc/group file.
	 */
	if (initgroups (info->pw_name, info->pw_gid) == -1) {
		int err = errno;
		perror ("initgroups");
		SYSLOG ((LOG_ERR, "initgroups failed for user `%s': %s\n",
		         info->pw_name, strerror (err)));
		closelog ();
		return -1;
	}
#endif
	return 0;
}

int change_uid (const struct passwd *info)
{
	/*
	 * Set the real UID to the UID value in the password file.
	 */
	if (setuid (info->pw_uid) != 0) {
		int err = errno;
		perror ("setuid");
		SYSLOG ((LOG_ERR, "bad user ID `%d' for user `%s': %s\n",
		         (int) info->pw_uid, info->pw_name, strerror (err)));
		closelog ();
		return -1;
	}
	return 0;
}

/*
 *	setup_uid_gid() performs the following steps -
 *
 *	set the group ID to the value from the password file entry
 *	set the supplementary group IDs
 *	optionally call specified function which may add more groups
 *	set the user ID to the value from the password file entry
 *
 *	Returns 0 on success, or -1 on failure.
 */

#if defined (HAVE_INITGROUPS) && ! (defined USE_PAM)
int setup_uid_gid (const struct passwd *info, bool is_console)
#else
int setup_uid_gid (const struct passwd *info)
#endif
{
	if (setup_groups (info) < 0) {
		return -1;
	}

#if defined (HAVE_INITGROUPS) && ! defined (USE_PAM)
	if (is_console) {
		char *cp = getdef_str ("CONSOLE_GROUPS");

		if ((NULL != cp) && (add_groups (cp) != 0)) {
			perror ("Warning: add_groups");
		}
	}
#endif				/* HAVE_INITGROUPS && !USE_PAM*/

	if (change_uid (info) < 0) {
		return -1;
	}

	return 0;
}