Re: RFC: seccomp-bpf support

Hi,

On 2019-08-28 15:02:17 -0400, Joshua Brindle wrote:
> On Wed, Aug 28, 2019 at 2:53 PM Andres Freund <andres@anarazel.de> wrote:
> > On 2019-08-28 14:47:04 -0400, Joshua Brindle wrote:
> > > A prime example is madvise() which was a catastrophic failure that 1)
> > > isn't preventable by any LSM including SELinux, 2) isn't used by PG
> > > and is therefore a good candidate for a kill list, and 3) a clear win
> > > in the dont-let-PG-be-a-vector-for-kernel-compromise arena.
> >
> > IIRC it's used by glibc as part of its malloc implementation (also
> > threading etc) - but not necessarily hit during the most common
> > paths. That's *precisely* my problem with this approach.
> >
> 
> As long as glibc handles a returned error cleanly the syscall could be
> denied without harming the process and the bug would be mitigated.

And we'd hit mysterious slowdowns in production uses of PG when seccomp
is enabled.

Greetings,

Andres Freund