Re: [Qemu-devel] [PATCH] Add syscalls for -runas and -chroot to the seccomp sandbox

[Eduardo Otubo]

On Fri, Oct 02, 2015 at 12=05=58PM +0200, Markus Armbruster wrote:
> "Daniel P. Berrange" <address@hidden> writes:
> 
> > On Thu, Oct 01, 2015 at 02:06:32PM +0200, Markus Armbruster wrote:
> >> "Namsun Ch'o" <address@hidden> writes:
> >> 
> >> > The seccomp sandbox doesn't whitelist setuid, setgid, or
> >> > setgroups, which are
> >> > needed for -runas to work. It also doesn't whitelist chroot, which is 
> >> > needed
> >> > for the -chroot option. Unfortunately, QEMU enables seccomp before it 
> >> > drops
> >> > privileges or chroots, so without these whitelisted, -runas and
> >> > -chroot cause
> >> > QEMU to be killed with -sandbox on. This patch adds those syscalls.
> >> 
> >> Should it enable seccomp a bit later?
> >
> > Yeah, I think it would be better to move the seccomp enablement later.
> 
> Let's do that then.

Where exactly you guys think we could call seccomp enablement? Right
it's called (almost) right before cpu_exec_init_all(), on vl.c:4013. I
guess it is as later as it could.

> 
> > Adding setuid and chroot to the allow list is pretty strongly undesirable
> > from a security protection POV.
> 
> Indeed.

-- 
Eduardo Otubo
ProfitBricks GmbH

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