Re: [PATCHv3 2/2] arm64: Add support for STACKLEAK gcc plugin

[Alexander Popov]

On 21.07.2018 00:41, Laura Abbott wrote:
> This adds support for the STACKLEAK gcc plugin to arm64 by implementing
> stackleak_check_alloca(), based heavily on the x86 version, and adding the
> two helpers used by the stackleak common code: current_top_of_stack() and
> on_thread_stack(). The stack erasure calls are made at syscall returns.
> Additionally, this disables the plugin in hypervisor and EFI stub code,
> which are out of scope for the protection.
> 
> Reviewed-by: Mark Rutland <mark.rutland@xxxxxxx>
> Reviewed-by: Kees Cook <keescook@xxxxxxxxxxxx>
> Signed-off-by: Laura Abbott <labbott@xxxxxxxxxx>
> ---
> v3: Actual commit text courtesy of Kees. A comment explaining why we
> panic
> ---
>  arch/arm64/Kconfig                    |  1 +
>  arch/arm64/include/asm/processor.h    | 15 +++++++++++++++
>  arch/arm64/kernel/entry.S             |  7 +++++++
>  arch/arm64/kernel/process.c           | 22 ++++++++++++++++++++++
>  arch/arm64/kvm/hyp/Makefile           |  3 ++-
>  drivers/firmware/efi/libstub/Makefile |  3 ++-
>  6 files changed, 49 insertions(+), 2 deletions(-)

Laura, thanks for your work!

I've reviewed and tested this patch on my LeMaker HiKey board (HiSilicon Kirin
620 SoC). The lkdtm tests for STACKLEAK work fine.

Acked-by: Alexander Popov <alex.popov@xxxxxxxxx>

For testing I applied your patches above Kees' for-next/kspp:
https://git.kernel.org/pub/scm/linux/kernel/git/kees/linux.git/log/?h=for-next/kspp

I've had one trouble with building CONFIG_STACKLEAK_RUNTIME_DISABLE on arm64.
Kees, could you please fold this into the 7th patch of the series?

---- >8 ----

diff --git a/kernel/stackleak.c b/kernel/stackleak.c
index f731c9a..03031f7a 100644
--- a/kernel/stackleak.c
+++ b/kernel/stackleak.c
@@ -16,6 +16,7 @@

 #ifdef CONFIG_STACKLEAK_RUNTIME_DISABLE
 #include <linux/jump_label.h>
+#include <linux/sysctl.h>

 static DEFINE_STATIC_KEY_FALSE(stack_erasing_bypass);