Re: [PATCH 13/15] selftests/seccomp: powerpc: Set syscall return during ptrace syscall exit

Kees Cook
2020-09-14T20:27:46Z

On Mon, Sep 14, 2020 at 03:47:13PM +1000, Michael Ellerman wrote:
> Kees Cook <keescook@chromium.org> writes:
> > Some archs (like ppc) only support changing the return code during
> > syscall exit when ptrace is used. As the syscall number might not
> > be available anymore during syscall exit, it needs to be saved
> > during syscall enter. Adjust the ptrace tests to do this.
>
> I'm not that across all the fixture stuff, but if I'm reading it right
> you're now calling change_syscall() on both entry and exit for all
> arches.

Correct.

> That should work, but it no longer tests changing the return code on
> entry on the arches that support it, which seems like a backward step?

That's a good point. I wouldn't be in a position to notice a regression
for the other architectures. I will refactor this one...

--
Kees Cook