| Message ID | 20210427204720.25007-7-yu-cheng.yu@intel.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | Control-flow Enforcement: Indirect Branch Tracking | expand |
On Tue, Apr 27, 2021 at 01:47:17PM -0700, 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>
On 4/28/2021 1:33 PM, Kees Cook wrote: > On Tue, Apr 27, 2021 at 01:47:17PM -0700, 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. > > If you respin this, you can maybe rephrase this since CONFIG_X86_IBT > has already tested for the compiler support. > Yes, I will fix this. Thanks for reviewing! Yu-cheng >> >> Signed-off-by: H.J. Lu <hjl.tools@gmail.com> >> Signed-off-by: Yu-cheng Yu <yu-cheng.yu@intel.com> >> Cc: Andy Lutomirski <luto@kernel.org> >> Cc: Kees Cook <keescook@chromium.org> > > Reviewed-by: Kees Cook <keescook@chromium.org> > > -Kees > >> --- >> v24: >> - Replace CONFIG_X86_CET with CONFIG_X86_IBT to reflect splitting of shadow >> stack and ibt. >> >> arch/x86/entry/vdso/Makefile | 4 ++++ >> 1 file changed, 4 insertions(+) >> >> diff --git a/arch/x86/entry/vdso/Makefile b/arch/x86/entry/vdso/Makefile >> index 05c4abc2fdfd..a773a5f03b63 100644 >> --- a/arch/x86/entry/vdso/Makefile >> +++ b/arch/x86/entry/vdso/Makefile >> @@ -93,6 +93,10 @@ endif >> >> $(vobjs): KBUILD_CFLAGS := $(filter-out $(CC_FLAGS_LTO) $(GCC_PLUGINS_CFLAGS) $(RETPOLINE_CFLAGS),$(KBUILD_CFLAGS)) $(CFL) >> >> +ifdef CONFIG_X86_IBT >> +$(vobjs) $(vobjs32): KBUILD_CFLAGS += -fcf-protection=branch >> +endif >> + >> # >> # vDSO code runs in userspace and -pg doesn't help with profiling anyway. >> # >> -- >> 2.21.0 >> >
diff --git a/arch/x86/entry/vdso/Makefile b/arch/x86/entry/vdso/Makefile index 05c4abc2fdfd..a773a5f03b63 100644 --- a/arch/x86/entry/vdso/Makefile +++ b/arch/x86/entry/vdso/Makefile @@ -93,6 +93,10 @@ endif $(vobjs): KBUILD_CFLAGS := $(filter-out $(CC_FLAGS_LTO) $(GCC_PLUGINS_CFLAGS) $(RETPOLINE_CFLAGS),$(KBUILD_CFLAGS)) $(CFL) +ifdef CONFIG_X86_IBT +$(vobjs) $(vobjs32): KBUILD_CFLAGS += -fcf-protection=branch +endif + # # vDSO code runs in userspace and -pg doesn't help with profiling anyway. #