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

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commit 325c50e3cebb9208009083e841550f98a863bfa0 upstream.

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: cb8e70901d (Btrfs: Fix subvolume creation locking rules)
Fixes: 76dda93c6a (Btrfs: add snapshot/subvolume destroy ioctl)
Signed-off-by: Jeff Mahoney <jeffm@suse.com>
Signed-off-by: Chris Mason <clm@fb.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Jeff Mahoney 2016-09-21 08:31:29 -04:00 committed by Greg Kroah-Hartman
parent f1b01a340b
commit e944e69815
1 changed files with 12 additions and 0 deletions
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12
fs/btrfs/ioctl.c
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@ -1619,6 +1619,9 @@ 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;
@ -1676,6 +1679,9 @@ 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);
@ -1699,6 +1705,9 @@ 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);
@ -2345,6 +2354,9 @@ 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);