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

[Will Deacon]

On Fri, Dec 01, 2017 at 12:10:00PM -0800, Kees Cook 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.

Should we be defaulting IO_STRICT_DEVMEM on as well?

Will

> Signed-off-by: Kees Cook <keescook@xxxxxxxxxxxx>
> ---
>  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