Re: [5.2 REGRESSION] Generic vDSO breaks seccomp-enabled userspace on i386

[Thomas Gleixner]

On Tue, 23 Jul 2019, Kees Cook wrote:

> On Wed, Jul 24, 2019 at 12:59:03AM +0200, Thomas Gleixner wrote:
> > And as we have sys_clock_gettime64() exposed for 32bit anyway you need to
> > deal with that in seccomp independently of the VDSO. It does not make sense
> > to treat sys_clock_gettime() differently than sys_clock_gettime64(). They
> > both expose the same information, but the latter is y2038 safe.
> 
> Okay, so combining Andy's ideas on aliasing and "more seccomp flags",
> we could declare that clock_gettime64() is not filterable on 32-bit at
> all without the magic SECCOMP_IGNORE_ALIASES flag or something. Then we
> would alias clock_gettime64 to clock_gettime _before_ the first evaluation
> (unless SECCOMP_IGNORE_ALIASES is set)?
> 
> (When was clock_gettime64() introduced? Is it too long ago to do this
> "you can't filter it without a special flag" change?)

clock_gettime64() and the other sys_*time64() syscalls which address the
y2038 issue were added in 5.1

Thanks,

	tglx