Re: [RFC] selftests/x86: Add test_vsyscall

[Andy Lutomirski]

On Fri, Jan 5, 2018 at 4:33 AM, Borislav Petkov <bp@xxxxxxxxx> wrote:
> On Thu, Jan 04, 2018 at 09:38:37PM -0800, Andy Lutomirski wrote:
>> Also, I want to add vsyscall=emulate_noread that makes the vsyscall
>> page be --x.  And I want to add a per-process option to turn off
>> vsyscalls.
>
> What for?
>
> It sounds like a bunch of work for something which is deprecated
> anyway...
>

emulate_noread would avoid one exploit technique that Kees saw
somewhere.  And per-process disablement would let a system remain
compatible with old binaries without reducing security for newer
binaries.