On Thu, Jan 30, 2025 at 7:57 AM Kees Cook [off-list ref] wrote:

On Thu, Jan 30, 2025 at 07:05:42AM -0800, Eyal Birger wrote:

quoted

So if we go with the suggestion above, we'll support the theoretical
__NR_uretprobe_32 for filtered seccomp, but not for strict seccomp, and
that's ok because strict seccomp is less common?

It's so uncommon I regularly consider removing it entirely. :)

quoted

Personally I'd prefer to limit the scope of this fix to the problem we
are aware of, and not possible problems should someone decide to reimplement
uretprobes on different archs in a different way. Especially as this fix needs
to be backmerged to stable kernels.
So my personal preference would be to avoid __NR_uretprobe_32 in this patch
and deal with it if it ever gets implemented.

That's fine, but I want the exception to be designed to fail closed
instead of failing open. I think my proposed future-proof check does
this.

I think it does. I think the code in the patch does too, since it
avoids the special handling for compat, so defaults to the existing
behavior which blocks the syscall.

Eyal.