Re: [RFC PATCH for 4.18 1/2] rseq: validate rseq_cs fields are < T ...

Linus Torvalds writes: (Summary) On Thu, Jun 28, 2018 at 4:30 PM Andy Lutomirski <luto@kernel.org> wrote:

[...]

(when they actually mean 0x00045678), we want to something consistent. I think the "something consistent" is perfectly fine with just "it won't work". I think the "something consistent" is perfectly fine with just "it won't work". Make it do
Make it do

        if (rseq_cs->abort_ip != (unsigned long)rseq_cs->abort_ip)
                return -EINVAL;

If it's a 32-bit kernel, the above will reject the thing, and if it's
a 64-bit kernel, it will be a no-op, but the abort won't work in a
32-bit caller.