lk/linux-kernel-test
1
0
Fork 0
Code Issues Pull Requests Releases Wiki Activity

[PATCH] r/o bind mounts: elevate write count for ioctls()

Browse Source 
Some ioctl()s can cause writes to the filesystem.  Take these, and make them
use mnt_want/drop_write() instead.

[AV: updated]

Acked-by: Al Viro <viro@ZenIV.linux.org.uk>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Dave Hansen <haveblue@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
This commit is contained in:
Dave Hansen
2008-02-15 14:37:46 -08:00
committed by Al Viro
parent 20ddee2c75
commit 42a74f206b
9 changed files with 264 additions and 154 deletions
Download Patch File Download Diff File Expand all files Collapse all files

33
fs/jfs/ioctl.c
View File

@@ -8,6 +8,7 @@
#include <linux/fs.h>
#include <linux/ctype.h>
#include <linux/capability.h>
#include <linux/mount.h>
#include <linux/time.h>
#include <linux/sched.h>
#include <asm/current.h>
@@ -65,23 +66,30 @@ long jfs_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
return put_user(flags, (int __user *) arg);
case JFS_IOC_SETFLAGS: {
unsigned int oldflags;
int err;
if (IS_RDONLY(inode))
return -EROFS;
err = mnt_want_write(filp->f_path.mnt);
if (err)
return err;
if (!is_owner_or_cap(inode))
return -EACCES;
if (get_user(flags, (int __user *) arg))
return -EFAULT;
if (!is_owner_or_cap(inode)) {
err = -EACCES;
goto setflags_out;
}
if (get_user(flags, (int __user *) arg)) {
err = -EFAULT;
goto setflags_out;
}
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;
if (IS_NOQUOTA(inode)) {
err = -EPERM;
goto setflags_out;
}
/* Lock against other parallel changes of flags */
mutex_lock(&inode->i_mutex);
@@ -98,7 +106,8 @@ long jfs_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
(JFS_APPEND_FL | JFS_IMMUTABLE_FL))) {
if (!capable(CAP_LINUX_IMMUTABLE)) {
mutex_unlock(&inode->i_mutex);
return -EPERM;
err = -EPERM;
goto setflags_out;
}
}
@@ -110,7 +119,9 @@ long jfs_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
mutex_unlock(&inode->i_mutex);
inode->i_ctime = CURRENT_TIME_SEC;
mark_inode_dirty(inode);
return 0;
setflags_out:
mnt_drop_write(filp->f_path.mnt);
return err;
}
default:
return -ENOTTY;