Re: [Ksummit-discuss] [TECH TOPIC] seccomp feature development

On Wed, May 20, 2020 at 05:31:02PM +0100, Al Viro wrote:
> On Wed, May 20, 2020 at 09:17:41AM -0700, Kees Cook wrote:
> > As recently outlined[1], there are are a number of seccomp topics that
> > need discussion:
> > 
> >  - fd passing
> >  - deep argument inspection
> >  - changing structure sizes
> >  - syscall bitmasks
> > 
> > Specifically, seccomp needs to grow the ability to inspect Extensible
> > Argument syscalls, which requires that it inspect userspace memory
> > without Time-of-Check/Time-of-Use races and without double-copying.
> > Additionally, since the structures can grow and be nested, there needs
> > to be a way to
> 
> ... catch and kill the bullshit ABI "enhancements" that would attempt that
> kind of garbage.  I'm not sure why that is seccomp-related, though...

We already have structs passed to syscalls that contain pointers to yet
more structs. Do you mean those should be disallowed? (Personally, I
would love that, but this doesn't seem to match the reality of the
design considerations of those syscalls.)

-- 
Kees Cook
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