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Commit 325c50e3 authored by Jeff Mahoney's avatar Jeff Mahoney Committed by Chris Mason
Browse files

btrfs: ensure that file descriptor used with subvol ioctls is a dir 



If the subvol/snapshot create/destroy ioctls are passed a regular file
with execute permissions set, we'll eventually Oops while trying to do
inode->i_op->lookup via lookup_one_len.

This patch ensures that the file descriptor refers to a directory.

Fixes: cb8e7090 (Btrfs: Fix subvolume creation locking rules)
Fixes: 76dda93c (Btrfs: add snapshot/subvolume destroy ioctl)
Cc: <stable@vger.kernel.org> #v2.6.29+
Signed-off-by: default avatarJeff Mahoney <jeffm@suse.com>
Signed-off-by: default avatarChris Mason <clm@fb.com>
parent 1e5ec2e7

fs/btrfs/ioctl.c

+12 −0
Original line number Diff line number Diff line
@@ -1634,6 +1634,9 @@ static noinline int btrfs_ioctl_snap_create_transid(struct file *file, 
	int namelen;

	int ret = 0;



	if (!S_ISDIR(file_inode(file)->i_mode))

		return -ENOTDIR;



	ret = mnt_want_write_file(file);

	if (ret)

		goto out;
@@ -1691,6 +1694,9 @@ static noinline int btrfs_ioctl_snap_create(struct file *file, 
	struct btrfs_ioctl_vol_args *vol_args;

	int ret;



	if (!S_ISDIR(file_inode(file)->i_mode))

		return -ENOTDIR;



	vol_args = memdup_user(arg, sizeof(*vol_args));

	if (IS_ERR(vol_args))

		return PTR_ERR(vol_args);
@@ -1714,6 +1720,9 @@ static noinline int btrfs_ioctl_snap_create_v2(struct file *file, 
	bool readonly = false;

	struct btrfs_qgroup_inherit *inherit = NULL;



	if (!S_ISDIR(file_inode(file)->i_mode))

		return -ENOTDIR;



	vol_args = memdup_user(arg, sizeof(*vol_args));

	if (IS_ERR(vol_args))

		return PTR_ERR(vol_args);
@@ -2357,6 +2366,9 @@ static noinline int btrfs_ioctl_snap_destroy(struct file *file, 
	int ret;

	int err = 0;



	if (!S_ISDIR(dir->i_mode))

		return -ENOTDIR;



	vol_args = memdup_user(arg, sizeof(*vol_args));

	if (IS_ERR(vol_args))

		return PTR_ERR(vol_args);