Commit e441d54d authored by Chris Mason's avatar Chris Mason
Browse files

Btrfs: add permission checks to the ioctls 



Only root can add/remove devices
Only root can defrag subtrees
Only files open for writing can be defragged
Only files open for writing can be the destination for a clone

Signed-off-by: default avatarChris Mason <chris.mason@oracle.com>
parent b34b086c

fs/btrfs/ioctl.c

+23 −2
Original line number Diff line number Diff line
@@ -453,6 +453,9 @@ static int btrfs_ioctl_resize(struct btrfs_root *root, void __user *arg) 
	if (root->fs_info->sb->s_flags & MS_RDONLY)

		return -EROFS;



	if (!capable(CAP_SYS_ADMIN))

		return -EPERM;



	vol_args = kmalloc(sizeof(*vol_args), GFP_NOFS);



	if (!vol_args)
@@ -638,16 +641,24 @@ static int btrfs_ioctl_defrag(struct file *file) 


	switch (inode->i_mode & S_IFMT) {

	case S_IFDIR:

		if (!capable(CAP_SYS_ADMIN)) {

			ret = -EPERM;

			goto out;

		}

		btrfs_defrag_root(root, 0);

		btrfs_defrag_root(root->fs_info->extent_root, 0);

		break;

	case S_IFREG:

		if (!(file->f_mode & FMODE_WRITE)) {

			ret = -EINVAL;

			goto out;

		}

		btrfs_defrag_file(file);

		break;

	}



out:

	mnt_drop_write(file->f_path.mnt);

	return 0;

	return ret;

}



static long btrfs_ioctl_add_dev(struct btrfs_root *root, void __user *arg)
@@ -655,6 +666,9 @@ static long btrfs_ioctl_add_dev(struct btrfs_root *root, void __user *arg) 
	struct btrfs_ioctl_vol_args *vol_args;

	int ret;



	if (!capable(CAP_SYS_ADMIN))

		return -EPERM;



	vol_args = kmalloc(sizeof(*vol_args), GFP_NOFS);



	if (!vol_args)
@@ -677,6 +691,9 @@ static long btrfs_ioctl_rm_dev(struct btrfs_root *root, void __user *arg) 
	struct btrfs_ioctl_vol_args *vol_args;

	int ret;



	if (!capable(CAP_SYS_ADMIN))

		return -EPERM;



	if (root->fs_info->sb->s_flags & MS_RDONLY)

		return -EROFS;
@@ -726,6 +743,10 @@ static long btrfs_ioctl_clone(struct file *file, unsigned long srcfd, 
	 *   they don't overlap)?

	 */



	/* the destination must be opened for writing */

	if (!(file->f_mode & FMODE_WRITE))

		return -EINVAL;



	ret = mnt_want_write(file->f_path.mnt);

	if (ret)

		return ret;

fs/btrfs/super.c

+3 −0
Original line number Diff line number Diff line
@@ -589,6 +589,9 @@ static long btrfs_control_ioctl(struct file *file, unsigned int cmd, 
	int ret = 0;

	int len;



	if (!capable(CAP_SYS_ADMIN))

		return -EPERM;



	vol = kmalloc(sizeof(*vol), GFP_KERNEL);

	if (copy_from_user(vol, (void __user *)arg, sizeof(*vol))) {

		ret = -EFAULT;