Re: [PATCH] seccomp: Use -1 marker for end of mode 1 syscall list

[Andy Lutomirski]

On Fri, Jun 19, 2020 at 12:53 PM Kees Cook <keescook@xxxxxxxxxxxx> wrote:
>
> On Fri, Jun 19, 2020 at 12:42:14PM -0700, Andy Lutomirski wrote:
> > On Fri, Jun 19, 2020 at 12:37 PM Kees Cook <keescook@xxxxxxxxxxxx> wrote:
> > >
> > > The terminator for the mode 1 syscalls list was a 0, but that could be
> > > a valid syscall number (e.g. x86_64 __NR_read). By luck, __NR_read was
> > > listed first and the loop construct would not test it, so there was no
> > > bug. However, this is fragile. Replace the terminator with -1 instead,
> > > and make the variable name for mode 1 syscall lists more descriptive.
> >
> > Could the architecture instead supply the length of the list?
>
> It could, but I didn't like the way the plumbing for that looked.

Fair enough.

>
> --
> Kees Cook