path: root/mount.cifs.c

/* 
   Mount helper utility for Linux CIFS VFS (virtual filesystem) client
   Copyright (C) 2003,2008 Steve French  (sfrench@us.ibm.com)
   Copyright (C) 2008 Jeremy Allison (jra@samba.org)

   This program is free software; you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation; either version 3 of the License, or
   (at your option) any later version.
   
   This program is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU General Public License for more details.
   
   You should have received a copy of the GNU General Public License
   along with this program.  If not, see <http://www.gnu.org/licenses/>.  */

#ifdef HAVE_CONFIG_H
#include "config.h"
#endif /* HAVE_CONFIG_H */

#include <stdlib.h>
#include <stdio.h>
#include <unistd.h>
#include <pwd.h>
#include <grp.h>
#include <ctype.h>
#include <sys/types.h>
#include <sys/mount.h>
#include <sys/stat.h>
#include <sys/utsname.h>
#include <sys/socket.h>
#include <arpa/inet.h>
#include <getopt.h>
#include <errno.h>
#include <netdb.h>
#include <string.h>
#include <mntent.h>
#include <fcntl.h>
#include <limits.h>
#include <fstab.h>
#include "mount.h"
#include "util.h"

#ifndef MS_MOVE 
#define MS_MOVE 8192 
#endif 

#ifndef MS_BIND
#define MS_BIND 4096
#endif

/* private flags - clear these before passing to kernel */
#define MS_USERS	0x40000000
#define MS_USER		0x80000000

#define MAX_UNC_LEN 1024

/* I believe that the kernel limits options data to a page */
#define MAX_OPTIONS_LEN	4096

/*
 * Maximum length of "share" portion of a UNC. I have no idea if this is at
 * all valid. According to MSDN, the typical max length of any component is
 * 255, so use that here.
 */
#define MAX_SHARE_LEN 256

/* max length of username (somewhat made up here) */
#define MAX_USERNAME_SIZE 32

/* currently maximum length of IPv6 address string */
#define MAX_ADDRESS_LEN INET6_ADDRSTRLEN

/* limit list of addresses to 16 max-size addrs */
#define MAX_ADDR_LIST_LEN ((MAX_ADDRESS_LEN + 1) * 16)

#ifndef SAFE_FREE
#define SAFE_FREE(x) do { if ((x) != NULL) {free(x); x=NULL;} } while(0)
#endif

#define MOUNT_PASSWD_SIZE 128
#define DOMAIN_SIZE 64

/*
 * value of the ver= option that gets passed to the kernel. Used to indicate
 * behavioral changes introduced in the mount helper.
 */
#define OPTIONS_VERSION "1"

/*
 * mount.cifs has been the subject of many "security" bugs that have arisen
 * because of users and distributions installing it as a setuid root program.
 * mount.cifs has not been audited for security. Thus, we strongly recommend
 * that it not be installed setuid root. To make that abundantly clear,
 * mount.cifs now check whether it's running setuid root and exit with an
 * error if it is. If you wish to disable this check, then set the following
 * #define to 1, but please realize that you do so at your own peril.
 */
#define CIFS_DISABLE_SETUID_CHECK 0

/*
 * When an unprivileged user runs a setuid mount.cifs, we set certain mount
 * flags by default. These defaults can be changed here.
 */
#define CIFS_SETUID_FLAGS (MS_NOSUID|MS_NODEV)

/* struct for holding parsed mount info for use by privleged process */
struct parsed_mount_info {
	unsigned long	flags;
	char		host[NI_MAXHOST + 1];
	char		share[MAX_SHARE_LEN + 1];
	char		prefix[PATH_MAX + 1];
	char		options[