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

From: Jiri Kosina
Date: Mon Mar 02 2015 - 04:39:40 EST


On Sat, 28 Feb 2015, Yinghai Lu wrote:

> We should access variable with referrence instead of using physical
> address as value.
>
> Cc: Matt Fleming <matt.fleming@xxxxxxxxx>
> Cc: Borislav Petkov <bp@xxxxxxx>
> Signed-off-by: Yinghai Lu <yinghai@xxxxxxxxxx>

Acked-by: Jiri Kosina <jkosina@xxxxxxx>


Thanks for fixing my brainfart. This is not fixing the problem with the
later variable overwrite, but definitely needs to go in as well.

Thanks.

> ---
> arch/x86/kernel/setup.c | 8 +++++++-
> 1 file changed, 7 insertions(+), 1 deletion(-)
>
> diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c
> index 98dc931..05d444f 100644
> --- a/arch/x86/kernel/setup.c
> +++ b/arch/x86/kernel/setup.c
> @@ -429,7 +429,13 @@ static void __init reserve_initrd(void)
>
> static void __init parse_kaslr_setup(u64 pa_data, u32 data_len)
> {
> - kaslr_enabled = (bool)(pa_data + sizeof(struct setup_data));
> + /* kaslr_setup_data is defined in aslr.c */
> + unsigned char *data;
> + unsigned long offset = sizeof(struct setup_data);
> +
> + data = early_memremap(pa_data, offset + 1);
> + kaslr_enabled = *(data + offset);
> + early_memunmap(data, offset + 1);
> }
>
> static void __init parse_setup_data(void)

--
Jiri Kosina
SUSE Labs
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