Re: [PATCH v3 5/7] x86, kaslr: Consolidate mem_avoid array filling

Kees Cook
2015-03-10T01:26:10Z

On Mon, Mar 9, 2015 at 6:10 PM, Yinghai Lu <yinghai-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org> wrote:
> On Mon, Mar 9, 2015 at 6:00 PM, Kees Cook <keescook-F7+t8E8rja9g9hUCZPvPmw@public.gmane.org> wrote:
>> On Sat, Mar 7, 2015 at 2:07 PM, Yinghai Lu <yinghai-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org> wrote:
>>
>> This may be a stupid question, but are boot_params being used outside
>> of the compressed loader? If so, it might make sense to split that
>> change into a separate patch to go to stable, if it's causing
>> problems. (And document what problem is getting solved.)
>
> boot_params will keep the same and until it is passed
> x86_64_start_kernel in vmlinux.
> and there it will be copied, same as cmdline.
>
> but current kaslr only support random the base high, and it does not
> support kexec
> and current boot loader (grub2) put it really low. (under 1M). the
> real real_mode. :).

Oh right! Of course, thanks for the details. Yes, it was implicitly
ignored before, but now it needs to be explicitly ignored. Great,
thanks!

-Kees

>
> Thanks
>
> Yinghai

--
Kees Cook
Chrome OS Security