diff mbox series

[v19,7/7] x86/vdso: Insert endbr32/endbr64 to vDSO

Message ID 20210203225902.479-8-yu-cheng.yu@intel.com (mailing list archive)
State New, archived
Headers show
Series Control-flow Enforcement: Indirect Branch Tracking | expand

Commit Message

Yu-cheng Yu Feb. 3, 2021, 10:59 p.m. UTC 
From: "H.J. Lu" <hjl.tools@gmail.com>

When Indirect Branch Tracking (IBT) is enabled, vDSO functions may be
called indirectly, and must have ENDBR32 or ENDBR64 as the first
instruction.  The compiler must support -fcf-protection=branch so that it
can be used to compile vDSO.

Signed-off-by: H.J. Lu <hjl.tools@gmail.com>
Signed-off-by: Yu-cheng Yu <yu-cheng.yu@intel.com>
Acked-by: Andy Lutomirski <luto@kernel.org>
---
 arch/x86/entry/vdso/Makefile | 4 ++++
 1 file changed, 4 insertions(+)

Comments

Kees Cook Feb. 4, 2021, 7:50 p.m. UTC | #1 
On Wed, Feb 03, 2021 at 02:59:02PM -0800, Yu-cheng Yu wrote:
> From: "H.J. Lu" <hjl.tools@gmail.com>
> 
> When Indirect Branch Tracking (IBT) is enabled, vDSO functions may be
> called indirectly, and must have ENDBR32 or ENDBR64 as the first
> instruction.  The compiler must support -fcf-protection=branch so that it
> can be used to compile vDSO.
> 
> Signed-off-by: H.J. Lu <hjl.tools@gmail.com>

Reviewed-by: Kees Cook <keescook@chromium.org>
diff mbox series

Patch

diff --git a/arch/x86/entry/vdso/Makefile b/arch/x86/entry/vdso/Makefile
index 02e3e42f380b..ff7b56feb5c3 100644
--- a/arch/x86/entry/vdso/Makefile
+++ b/arch/x86/entry/vdso/Makefile
@@ -93,6 +93,10 @@  endif
 
 $(vobjs): KBUILD_CFLAGS := $(filter-out $(GCC_PLUGINS_CFLAGS) $(RETPOLINE_CFLAGS),$(KBUILD_CFLAGS)) $(CFL)
 
+ifdef CONFIG_X86_CET
+$(vobjs) $(vobjs32): KBUILD_CFLAGS += -fcf-protection=branch
+endif
+
 #
 # vDSO code runs in userspace and -pg doesn't help with profiling anyway.
 #