[RFC 17/17] arm64: compile the kernel with ptrauth -msign-return-address
From: Ramana Radhakrishnan <hidden>
Date: 2018-10-05 09:01:11
Also in:
kvmarm, linux-arch, lkml
On 05/10/2018 09:47, Kristina Martsenko wrote:
quoted hunk ↗ jump to hunk
Compile all functions with two ptrauth instructions: paciasp in the prologue to sign the return address, and autiasp in the epilogue to authenticate the return address. This should help protect the kernel against attacks using return-oriented programming. CONFIG_ARM64_PTR_AUTH enables pointer auth for both userspace and the kernel. Signed-off-by: Mark Rutland <mark.rutland@arm.com> Signed-off-by: Kristina Martsenko <redacted> --- arch/arm64/Makefile | 4 ++++ 1 file changed, 4 insertions(+)diff --git a/arch/arm64/Makefile b/arch/arm64/Makefile index 106039d25e2f..dbcd43ea99d8 100644 --- a/arch/arm64/Makefile +++ b/arch/arm64/Makefile@@ -56,6 +56,10 @@ KBUILD_AFLAGS += $(lseinstr) $(brokengasinst) KBUILD_CFLAGS += $(call cc-option,-mabi=lp64) KBUILD_AFLAGS += $(call cc-option,-mabi=lp64) +ifeq ($(CONFIG_ARM64_PTR_AUTH),y) +KBUILD_CFLAGS += -msign-return-address=all
Glad to see this being done and being proposed for mainline. I can see why you would prefer this though have you guys experimented at all with -msign-return-address=non-leaf as well ? Orthogonally and just fair warning - the command lines for this are also being revised to provide ROP and JOP protection using BTI from v8.5-a during the GCC-9 timeframe but I suspect that's a different option. regards Ramana Reviewed-by: Ramana Radhakrishnan <redacted>