lkml.org 
[lkml]   [2020]   [Sep]   [24]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCH 2/6] x86: Enable seccomp architecture tracking
On Thu, Sep 24, 2020 at 02:45:45AM +0200, Jann Horn wrote:
> On Thu, Sep 24, 2020 at 1:29 AM Kees Cook <keescook@chromium.org> wrote:
> > Provide seccomp internals with the details to calculate which syscall
> > table the running kernel is expecting to deal with. This allows for
> > efficient architecture pinning and paves the way for constant-action
> > bitmaps.
> [...]
> > diff --git a/arch/x86/include/asm/seccomp.h b/arch/x86/include/asm/seccomp.h
> [...]
> > +#ifdef CONFIG_X86_64
> [...]
> > +#else /* !CONFIG_X86_64 */
> > +# define SECCOMP_ARCH AUDIT_ARCH_I386
> > +#endif
>
> If we are on a 32-bit kernel, performing architecture number checks in
> the kernel is completely pointless, because we know that there is only
> a single architecture identifier under which syscalls can happen.
>
> While this patch is useful for enabling the bitmap logic in the
> following patches, I think it adds unnecessary overhead in the context
> of the previous patch.

That's what the RFC was trying to do (avoid the logic if there is only a
single arch known to the kernel). I will rework this a bit harder. :)

--
Kees Cook

\
 
 \ /
  Last update: 2020-09-24 09:14    [W:0.075 / U:2.268 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site