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

From: Borislav Petkov
Date: Sun Mar 01 2015 - 15:31:02 EST


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:

https://lkml.kernel.org/r/20150228105049.GA11038@xxxxxxx

--
Regards/Gruss,
Boris.

ECO tip #101: Trim your mails when you reply.
--
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/