Re: [kernel-hardening] [PATCH] Kconfig: Make STRICT_DEVMEM default-y on x86 and arm64

[Ard Biesheuvel]

On 1 December 2017 at 20:10, Kees Cook <keescook@xxxxxxxxxxxx> wrote:
> Distros have been shipping with CONFIG_STRICT_DEVMEM=y for years now. It
> is probably time to flip this default for x86 and arm64.
>
> Signed-off-by: Kees Cook <keescook@xxxxxxxxxxxx>

Acked-by: Ard Biesheuvel <ard.biesheuvel@xxxxxxxxxx>

> ---
>  lib/Kconfig.debug | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug
> index 947d3e2ed5c2..39b123d04a36 100644
> --- a/lib/Kconfig.debug
> +++ b/lib/Kconfig.debug
> @@ -1985,7 +1985,7 @@ config STRICT_DEVMEM
>         bool "Filter access to /dev/mem"
>         depends on MMU && DEVMEM
>         depends on ARCH_HAS_DEVMEM_IS_ALLOWED
> -       default y if TILE || PPC
> +       default y if TILE || PPC || X86 || ARM64
>         ---help---
>           If this option is disabled, you allow userspace (root) access to all
>           of memory, including kernel and userspace memory. Accidental
> --
> 2.7.4
>
>
> --
> Kees Cook
> Pixel Security