kernel-ark/fs/jfs/ioctl.c
Jan Kara e47776a0a4 Forbid user to change file flags on quota files
Forbid user from changing file flags on quota files.  User has no bussiness
in playing with these flags when quota is on.  Furthermore there is a
remote possibility of deadlock due to a lock inversion between quota file's
i_mutex and transaction's start (i_mutex for quota file is locked only when
trasaction is started in quota operations) in ext3 and ext4.

Signed-off-by: Jan Kara <jack@suse.cz>
Cc: LIOU Payphone <lioupayphone@gmail.com>
Cc: <linux-ext4@vger.kernel.org>
Acked-by: Dave Kleikamp <shaggy@austin.ibm.com>
Cc: <reiserfs-dev@namesys.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-11-14 18:45:38 -08:00

113 lines
2.3 KiB
C

/*
* linux/fs/jfs/ioctl.c
*
* Copyright (C) 2006 Herbert Poetzl
* adapted from Remy Card's ext2/ioctl.c
*/
#include <linux/fs.h>
#include <linux/ctype.h>
#include <linux/capability.h>
#include <linux/time.h>
#include <linux/sched.h>
#include <asm/current.h>
#include <asm/uaccess.h>
#include "jfs_incore.h"
#include "jfs_dinode.h"
#include "jfs_inode.h"
static struct {
long jfs_flag;
long ext2_flag;
} jfs_map[] = {
{JFS_NOATIME_FL, FS_NOATIME_FL},
{JFS_DIRSYNC_FL, FS_DIRSYNC_FL},
{JFS_SYNC_FL, FS_SYNC_FL},
{JFS_SECRM_FL, FS_SECRM_FL},
{JFS_UNRM_FL, FS_UNRM_FL},
{JFS_APPEND_FL, FS_APPEND_FL},
{JFS_IMMUTABLE_FL, FS_IMMUTABLE_FL},
{0, 0},
};
static long jfs_map_ext2(unsigned long flags, int from)
{
int index=0;
long mapped=0;
while (jfs_map[index].jfs_flag) {
if (from) {
if (jfs_map[index].ext2_flag & flags)
mapped |= jfs_map[index].jfs_flag;
} else {
if (jfs_map[index].jfs_flag & flags)
mapped |= jfs_map[index].ext2_flag;
}
index++;
}
return mapped;
}
int jfs_ioctl(struct inode * inode, struct file * filp, unsigned int cmd,
unsigned long arg)
{
struct jfs_inode_info *jfs_inode = JFS_IP(inode);
unsigned int flags;
switch (cmd) {
case JFS_IOC_GETFLAGS:
jfs_get_inode_flags(jfs_inode);
flags = jfs_inode->mode2 & JFS_FL_USER_VISIBLE;
flags = jfs_map_ext2(flags, 0);
return put_user(flags, (int __user *) arg);
case JFS_IOC_SETFLAGS: {
unsigned int oldflags;
if (IS_RDONLY(inode))
return -EROFS;
if (!is_owner_or_cap(inode))
return -EACCES;
if (get_user(flags, (int __user *) arg))
return -EFAULT;
flags = jfs_map_ext2(flags, 1);
if (!S_ISDIR(inode->i_mode))
flags &= ~JFS_DIRSYNC_FL;
/* Is it quota file? Do not allow user to mess with it */
if (IS_NOQUOTA(inode))
return -EPERM;
jfs_get_inode_flags(jfs_inode);
oldflags = jfs_inode->mode2;
/*
* The IMMUTABLE and APPEND_ONLY flags can only be changed by
* the relevant capability.
*/
if ((oldflags & JFS_IMMUTABLE_FL) ||
((flags ^ oldflags) &
(JFS_APPEND_FL | JFS_IMMUTABLE_FL))) {
if (!capable(CAP_LINUX_IMMUTABLE))
return -EPERM;
}
flags = flags & JFS_FL_USER_MODIFIABLE;
flags |= oldflags & ~JFS_FL_USER_MODIFIABLE;
jfs_inode->mode2 = flags;
jfs_set_inode_flags(inode);
inode->i_ctime = CURRENT_TIME_SEC;
mark_inode_dirty(inode);
return 0;
}
default:
return -ENOTTY;
}
}