Re: [PATCH 3/6] seccomp: Implement constant action bitmaps

[YiFei Zhu]

On Thu, Sep 24, 2020 at 2:38 AM Kees Cook <keescook@xxxxxxxxxxxx> wrote:
> > Would you mind educating me how this patch plan one handling MIPS? For
> > one kernel they seem to have up to three arch numbers per build,
> > AUDIT_ARCH_MIPS{,64,64N32}. Though ARCH_TRACE_IGNORE_COMPAT_SYSCALLS
> > does not seem to be defined for MIPS so I'm assuming the syscall
> > numbers are the same, but I think it is possible some client uses that
> > arch number to pose different constraints for different processes, so
> > it would better not accelerate them rather than break them.
>
> I'll take a look, but I'm hoping it won't be too hard to fit into what
> I've got designed so for to deal with x86_x32. (Will MIPS want this
> optimization at all?)

I just took a slightly closer look at MIPS and it seems that they have
sparse syscall numbers (defines HAVE_SPARSE_SYSCALL_NR). I don't know
how the different "regions of syscall numbers" are affected by arch
numbers, however...