Re: [tip:x86/urgent] x86-64, modify_ldt: Ban 16-bit segments on 64-bit kernels

Linus Torvalds
2014-04-13T03:13:28Z

On Sat, Apr 12, 2014 at 7:56 PM, Andi Kleen <andi@firstfloor.org> wrote:
>
> Why? Either it works or it doesn't.
>
> If it works it doesn't make any sense to have a sysctl.

BS.

It "works" exactly like mmap() at NULL "works".

It is a potential security leak, because x86-64 screwed up the
architecture definition in this area. So it should definitely be
disabled by default, exactly like mmap_min_addr is non-zero by
default.

Linus