Messages in this thread | | | Date | Fri, 15 Nov 2019 14:43:59 +0000 | From | Mark Rutland <> | Subject | Re: [PATCH v5 12/14] arm64: vdso: disable Shadow Call Stack |
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On Tue, Nov 05, 2019 at 03:56:06PM -0800, Sami Tolvanen wrote: > Shadow stacks are only available in the kernel, so disable SCS > instrumentation for the vDSO. > > Signed-off-by: Sami Tolvanen <samitolvanen@google.com> > Reviewed-by: Nick Desaulniers <ndesaulniers@google.com> > Reviewed-by: Kees Cook <keescook@chromium.org>
I gave this a spin, looked at objdump, and found everything in the vDSO was a leaf function. I hacked the code around a bit to force a function call, and I see that just uses x29 and x30 as expected, with nothing touching x18.
Reviewed-by: Mark Rutland <mark.rutland@arm.com>
Mark.
> --- > arch/arm64/kernel/vdso/Makefile | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/arch/arm64/kernel/vdso/Makefile b/arch/arm64/kernel/vdso/Makefile > index dd2514bb1511..a87a4f11724e 100644 > --- a/arch/arm64/kernel/vdso/Makefile > +++ b/arch/arm64/kernel/vdso/Makefile > @@ -25,7 +25,7 @@ ccflags-y += -DDISABLE_BRANCH_PROFILING > > VDSO_LDFLAGS := -Bsymbolic > > -CFLAGS_REMOVE_vgettimeofday.o = $(CC_FLAGS_FTRACE) -Os > +CFLAGS_REMOVE_vgettimeofday.o = $(CC_FLAGS_FTRACE) -Os $(CC_FLAGS_SCS) > KBUILD_CFLAGS += $(DISABLE_LTO) > KASAN_SANITIZE := n > UBSAN_SANITIZE := n > -- > 2.24.0.rc1.363.gb1bccd3e3d-goog >
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