Btrfs: ensure path name is null terminated at btrfs_control_ioctl
authorFilipe Manana <fdmanana@suse.com>
Wed, 14 Nov 2018 11:35:24 +0000 (11:35 +0000)
committerDavid Sterba <dsterba@suse.com>
Wed, 14 Nov 2018 17:26:20 +0000 (18:26 +0100)
commitf505754fd6599230371cb01b9332754ddc104be1
tree10539af0a48a44d8c861809bb1ea957e3599df4b
parentaab15e8ec25765cf7968c72cbec7583acf99d8a4
Btrfs: ensure path name is null terminated at btrfs_control_ioctl

We were using the path name received from user space without checking that
it is null terminated. While btrfs-progs is well behaved and does proper
validation and null termination, someone could call the ioctl and pass
a non-null terminated patch, leading to buffer overrun problems in the
kernel.  The ioctl is protected by CAP_SYS_ADMIN.

So just set the last byte of the path to a null character, similar to what
we do in other ioctls (add/remove/resize device, snapshot creation, etc).

CC: stable@vger.kernel.org # 4.4+
Reviewed-by: Anand Jain <anand.jain@oracle.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
fs/btrfs/super.c