Re: [PATCH 1/8] x86, kaslr: get kaslr_enabled back correctly

[Yinghai Lu]

On Sun, Mar 1, 2015 at 12:29 PM, Borislav Petkov <bp@xxxxxxx> wrote:
> On Sun, Mar 01, 2015 at 12:24:08PM -0800, Yinghai Lu wrote:
>> static allocation in misc.c can not be used to kernel/head_64.S stage safely.
>
> Correct. One possibility that works is sticking it right below
> LOAD_PHYSICAL_ADDR:
>
> +static void add_kaslr_setup_data(struct boot_params *params,
> +                                u8 *output, __u8 enabled)
>  {
> +       /*
> +        * Stick it right under LOAD_PHYSICAL_ADDR
> +        */
> +       ksd = (struct setup_data *)(output - 2 * sizeof(struct setup_data));
>
> output is LOAD_PHYSICAL_ADDR AFAICT and is the minimum kASLR considers
> so right below it should work:

Does not look safe yet...

Let me think about it more.

Thanks

Yinghai
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