Re: For review: seccomp_user_notif(2) manual page

[Jann Horn]

On Wed, Oct 28, 2020 at 11:56 PM Kees Cook <keescook@xxxxxxxxxxxx> wrote:
> On Mon, Oct 26, 2020 at 11:31:01AM +0100, Jann Horn wrote:
> > Or I guess we could also just set O_NONBLOCK on the fd by default?
> > Since the one existing user is eventloop-based...
>
> I thought about that initially, but it rubs me the wrong way: it
> violates least-surprise for me. File descriptors are expected to be
> default-blocking. It *is* a special fd, though, so maybe it could work.
> The only case I can think of it would break would be ioctl-loop case
> that is already buggy in that it didn't handle non-zero returns?

We don't have any actual users that use the API that way outside of
the kernel's selftest/sample code, right?