On Thu, Jun 28, 2018 at 4:30 PM Andy Lutomirski <l...@kernel.org> wrote:
>
> The idea is that, if someone screws up and sticks a number like
> 0xbaadf00d00045678 into their rseq abort_ip in a 32-bit x86 program
> (when they actually mean 0x00045678), we want to something consistent.
I think the "something consistent" is perfectly fine with just "it won't work".
Make it do
if (rseq_cs->abort_ip != (unsigned long)rseq_cs->abort_ip)
return -EINVAL;
at abort time.
Done.
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.
Problem solved.
Linus
