Re: [PATCH] security: select correct default LSM_MMAP_MIN_ADDR onarm on arm64

From: Will Deacon
Date: Tue Feb 04 2014 - 04:39:48 EST


On Tue, Feb 04, 2014 at 02:15:32AM +0000, Colin Cross wrote:
> Binaries compiled for arm may run on arm64 if CONFIG_COMPAT is
> selected. Set LSM_MMAP_MIN_ADDR to 32768 if ARM64 && COMPAT to
> prevent selinux failures launching 32-bit static executables that
> are mapped at 0x8000.
>
> Signed-off-by: Colin Cross <ccross@xxxxxxxxxxx>
> ---
> security/Kconfig | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/security/Kconfig b/security/Kconfig
> index e9c6ac724fef..beb86b500adf 100644
> --- a/security/Kconfig
> +++ b/security/Kconfig
> @@ -103,7 +103,7 @@ config INTEL_TXT
> config LSM_MMAP_MIN_ADDR
> int "Low address space for LSM to protect from user allocation"
> depends on SECURITY && SECURITY_SELINUX
> - default 32768 if ARM
> + default 32768 if ARM || (ARM64 && COMPAT)
> default 65536
> help
> This is the portion of low virtual memory which should be protected

Since ARM64 && COMPAT implies 4k pages, this change looks ok to me.

Acked-by: Will Deacon <will.deacon@xxxxxxx>

Will
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