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SubjectRe: [PATCH v3] retpoline: Add retpoline tag to VERMAGIC
On Tue, 16 Jan 2018, Andi Kleen wrote:

> From: Andi Kleen <ak@linux.intel.com>
>
> Add a marker for retpoline to the module VERMAGIC. This catches
> the case when a non RETPOLINE compiled module gets loaded into
> a retpoline kernel, making it insecure.
>
> It doesn't handle the case when retpoline has been runtime disabled.
> Even in this case the match of the retcompile status will be enforced.
> This implies that even with retpoline run time disabled all modules
> loaded need to be recompiled.
>
> This supersedes an earlier patch that did the same checking using
> a new module tag (so it's really a v3)
>
> Signed-off-by: Andi Kleen <ak@linux.intel.com>

Acked-by: Thomas Gleixner <tglx@linutronix.de>

> ---
> include/linux/vermagic.h | 8 +++++++-
> 1 file changed, 7 insertions(+), 1 deletion(-)
>
> diff --git a/include/linux/vermagic.h b/include/linux/vermagic.h
> index bae807eb2933..853291714ae0 100644
> --- a/include/linux/vermagic.h
> +++ b/include/linux/vermagic.h
> @@ -31,11 +31,17 @@
> #else
> #define MODULE_RANDSTRUCT_PLUGIN
> #endif
> +#ifdef RETPOLINE
> +#define MODULE_VERMAGIC_RETPOLINE "retpoline "
> +#else
> +#define MODULE_VERMAGIC_RETPOLINE ""
> +#endif
>
> #define VERMAGIC_STRING \
> UTS_RELEASE " " \
> MODULE_VERMAGIC_SMP MODULE_VERMAGIC_PREEMPT \
> MODULE_VERMAGIC_MODULE_UNLOAD MODULE_VERMAGIC_MODVERSIONS \
> MODULE_ARCH_VERMAGIC \
> - MODULE_RANDSTRUCT_PLUGIN
> + MODULE_RANDSTRUCT_PLUGIN \
> + MODULE_VERMAGIC_RETPOLINE
>
> --
> 2.14.3
>
>

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