linux-kernel - Re: [kernel-hardening] [PATCH v5 1/4] gcc-plugins: Add the initify gcc plugin

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Date:   Mon, 27 Mar 2017 18:38:20 +1100
From:   Andrew Donnellan <andrew.donnellan@....ibm.com>
To:     Kees Cook <keescook@...omium.org>, linux-kernel@...r.kernel.org
Cc:     Emese Revfy <re.emese@...il.com>, Arnd Bergmann <arnd@...db.de>,
        Josh Triplett <josh@...htriplett.org>, pageexec@...email.hu,
        yamada.masahiro@...ionext.com, minipli@...linux.so,
        linux@...linux.org.uk, catalin.marinas@....com,
        linux@...musvillemoes.dk, david.brown@...aro.org,
        benh@...nel.crashing.org, tglx@...utronix.de,
        akpm@...ux-foundation.org, jlayton@...chiereds.net,
        sam@...nborg.org, kernel-hardening@...ts.openwall.com
Subject: Re: [kernel-hardening] [PATCH v5 1/4] gcc-plugins: Add the initify
 gcc plugin

On 01/02/17 07:24, Kees Cook wrote:
> From: Emese Revfy <re.emese@...il.com>
>
> The kernel already has a mechanism to free up code and data memory that
> is only used during kernel or module initialization.  This plugin will
> teach the compiler to find more such code and data that can be freed
> after initialization.

Currently checking whether we can wire this up for powerpc without too 
many problems...

> diff --git a/arch/x86/lib/Makefile b/arch/x86/lib/Makefile
> index 34a74131a12c..b98b8fdb7aaf 100644
> --- a/arch/x86/lib/Makefile
> +++ b/arch/x86/lib/Makefile
> @@ -29,6 +29,10 @@ lib-$(CONFIG_RANDOMIZE_BASE) += kaslr.o
>  obj-y += msr.o msr-reg.o msr-reg-export.o hweight.o
>
>  ifeq ($(CONFIG_X86_32),y)
> +        CFLAGS_strstr_32.o += $(INITIFY_DISABLE_VERIFIY_NOCAPTURE_FUNCTIONS)
> +        CFLAGS_string_32.o += $(INITIFY_DISABLE_VERIFIY_NOCAPTURE_FUNCTIONS)
> +        CFLAGS_memcpy_32.o += $(INITIFY_DISABLE_VERIFIY_NOCAPTURE_FUNCTIONS)

s/VERIFIY/VERIFY/g here + Makefile.gcc-plugins?


-- 
Andrew Donnellan              OzLabs, ADL Canberra
andrew.donnellan@....ibm.com  IBM Australia Limited