Re: [PATCH 03/15] selftests/seccomp: mips: Define SYSCALL_NUM_SET macro

Kees Cook
2020-09-18T22:00:05Z

On Tue, Sep 15, 2020 at 05:55:46PM +0200, Christian Brauner wrote:
> On Sat, Sep 12, 2020 at 04:08:08AM -0700, Kees Cook wrote:
> > Remove the mips special-case in change_syscall().
> >
> > Signed-off-by: Kees Cook <keescook@chromium.org>
> > ---
> > tools/testing/selftests/seccomp/seccomp_bpf.c | 17 +++++++++--------
> > 1 file changed, 9 insertions(+), 8 deletions(-)
> >
> > diff --git a/tools/testing/selftests/seccomp/seccomp_bpf.c b/tools/testing/selftests/seccomp/seccomp_bpf.c
> > index 1c83e743bfb1..02a9a6599746 100644
> > --- a/tools/testing/selftests/seccomp/seccomp_bpf.c
> > +++ b/tools/testing/selftests/seccomp/seccomp_bpf.c
> > @@ -1742,6 +1742,13 @@ TEST_F(TRACE_poke, getpid_runs_normally)
> > # define ARCH_REGS struct pt_regs
> > # define SYSCALL_NUM(_regs) (_regs).regs[2]
> > # define SYSCALL_SYSCALL_NUM regs[4]
> > +# define SYSCALL_NUM_SET(_regs, _nr) \
> > + do { \
> > + if ((_regs).regs[2] == __NR_O32_Linux) \
> > + (_regs).regs[4] = _nr; \
> > + else \
> > + (_regs).regs[2] = _nr; \
> > + } while (0)
>
> I think that
>
> # define SYSCALL_NUM_SET(_regs, _nr) \
> do { \
> if (SYSCALL_NUM(_regs) == __NR_O32_Linux) \
> (_regs).regs[4] = _nr; \
> else \
> (_regs).regs[2] = _nr; \
> } while (0)
>
> would read better but that's just a matter of taste. :)

That's how I started originally, but when I realized that I'd have to
reorganize SYSCALL_NUM() too, it seem best to have minimal churn, so I
left it open coded here, since that's how it needs to be in the end.

> Looks good!
> Acked-by: Christian Brauner <christian.brauner@ubuntu.com>

Thanks for the reviews!

--
Kees Cook