Re: [RFC PATCH seccomp 2/2] seccomp/cache: Cache filter results that allow syscalls

From: YiFei Zhu
Date: Mon Sep 21 2020 - 19:08:13 EST

On Mon, Sep 21, 2020 at 5:58 PM Jann Horn <jannh@xxxxxxxxxx> wrote:
> > I do agree that an immutable bitmask is faster and easier to reason
> > about its correctness. However, I did not find the "code to statically
> > evaluate the filter for all syscall numbers" while reading seccomp.c.
> > Would you give me a pointer to that and I will see how to best make
> > use of it?
> I'm talking about the code you're adding in the other patch ("[RFC
> PATCH seccomp 1/2] seccomp/cache: Add "emulator" to check if filter is
> arg-dependent"). Sorry, that was a bit unclear.

I see, building an immutable accept bitmask when preparing and then
just use that when running it. I guess if the arch number issue is
resolved this should be more doable. Will do.

YiFei Zhu