[PATCH] tst-ttyname: skip the test when /dev/ptmx is not available

[Dmitry V. Levin]

On Mon, Dec 25, 2017 at 01:18:56PM -0800, Zack Weinberg wrote:
> On Mon, Dec 25, 2017 at 1:00 PM, Dmitry V. Levin <ldv@altlinux.org> wrote:
> > On Mon, Dec 25, 2017 at 12:09:56PM -0800, Zack Weinberg wrote:
> >> On Mon, Dec 25, 2017 at 11:12 AM, Dmitry V. Levin <ldv@altlinux.org> wrote:
> >> > On Mon, Dec 25, 2017 at 07:19:44PM +0100, Florian Weimer wrote:
> >> >> * Dmitry V. Levin:
> >> >>
> >> >> > * sysdeps/unix/sysv/linux/tst-ttyname.c (do_in_chroot_1): Skip the
> >> >> > test instead of failing in case of an error returned by posix_openpt.
> >> >>
> >> >> I think the test failure is real in this case.  I wouldn't it be?
> >> >
> >> > No, /dev/ptmx is intentionally missing in the environment where this test
> >> > failed.
> >>
> >> Why?
> >
> > It's a restricted environment.
> 
> Why is lack of access to pseudoterminals a useful restriction to
> apply?  What does it defend against?

The weakest point of that restricted environment is linux kernel,
so unused functionality is disabled to narrow the attack surface.


-- 
ldv
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