On Tue, 24 Apr 2018 12:00:58 +0100
Mark Rutland <[email protected]> wrote:
> When CONFIG_RANDOMIZE_TEXT_OFFSET is selected, TEXT_OFFSET is an
> arbitrary multiple of PAGE_SIZE in the interval [0, 2MB).
>
> The EFI stub doesn't accuont for this, and only handles the case where
> TEXT_OFFSET is multiple of EFI_KIMG_ALIGN. This can result in the kernel
> being loaded to an erroneous physical alignment. This has been observed
> to result in spurious stack overflow reports and failure to make use of
> the IRQ stacks, and theoretically could result in a number of other
> issues.
>
> We can OR in the low bits of TEXT_OFFSET to ensure that we have the
> necessary offset (and hence have the necessary alignment), so let's do
> that.
>
> Fixes: 6f26b3671184c36d ("arm64: kaslr: increase randomization granularity")
> Reported-by: Kim Phillips <[email protected]>
> Signed-off-by: Mark Rutland <[email protected]>
> Cc: Ard Biesheuvel <[email protected]>
> Cc: [email protected]
> ---
Tested-by: Kim Phillips <[email protected]>
Thanks,
Kim
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