Re: [PATCH 3.16 56/76] x86/syscall: Sanitize syscall table de-references under speculation

From: Ben Hutchings
Date: Sun Mar 18 2018 - 21:00:04 EST


On Mon, 2018-03-12 at 08:32 +0100, Jiri Slaby wrote:
> On 03/12/2018, 04:06 AM, Ben Hutchings wrote:
> > In 3.16 the x86_32 syscall table lookup is also written in assembly.
> > So I've taken Jiri's version and added similar masking in entry_32.S,
> > using edx as the temporary. edx is clobbered by SAVE_REGS and seems
> > to be free at this point.
>
> I don't know the state in 3.16, but in 3.12, I had to fix the 32bit
> entry on 64bit in arch/x86/ia32/ia32entry.S (ia32_sysenter_target &
> others) too.

Thank you, yes I need to fix them in 3.16 too. I also failed to use
retpolines there.

Ben.

--
Ben Hutchings
The first rule of tautology club is the first rule of tautology club.

Attachment: signature.asc
Description: This is a digitally signed message part