Messages in this thread | | | Subject | Re: [PATCH v27 10/10] x86/vdso: Add ENDBR to __vdso_sgx_enter_enclave | From | "Yu, Yu-cheng" <> | Date | Mon, 24 May 2021 12:01:48 -0700 |
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On 5/22/2021 3:47 PM, Jarkko Sakkinen wrote: > On Fri, May 21, 2021 at 03:15:31PM -0700, Yu-cheng Yu wrote: >> ENDBR is a special new instruction for the Indirect Branch Tracking (IBT) >> component of CET. IBT prevents attacks by ensuring that (most) indirect >> branches and function calls may only land at ENDBR instructions. Branches >> that don't follow the rules will result in control flow (#CF) exceptions. >> >> ENDBR is a noop when IBT is unsupported or disabled. Most ENDBR >> instructions are inserted automatically by the compiler, but branch >> targets written in assembly must have ENDBR added manually. >> >> Add ENDBR to __vdso_sgx_enter_enclave() branch targets. >> >> Signed-off-by: Yu-cheng Yu <yu-cheng.yu@intel.com> >> Reviewed-by: Kees Cook <keescook@chromium.org> >> Cc: Andy Lutomirski <luto@kernel.org> >> Cc: Borislav Petkov <bp@alien8.de> >> Cc: Dave Hansen <dave.hansen@linux.intel.com> >> Cc: Jarkko Sakkinen <jarkko@kernel.org> >> Cc: Peter Zijlstra <peterz@infradead.org> > > > Acked-by: Jarkko Sakkinen <jarkko@kernel.org> > >> --- >> arch/x86/entry/vdso/vsgx.S | 4 ++++ >> 1 file changed, 4 insertions(+) >> >> diff --git a/arch/x86/entry/vdso/vsgx.S b/arch/x86/entry/vdso/vsgx.S >> index 99dafac992e2..c7cb85d57b3f 100644 >> --- a/arch/x86/entry/vdso/vsgx.S >> +++ b/arch/x86/entry/vdso/vsgx.S >> @@ -4,6 +4,7 @@ >> #include <asm/export.h> >> #include <asm/errno.h> >> #include <asm/enclu.h> >> +#include <asm/vdso.h> >> >> #include "extable.h" >> >> @@ -27,6 +28,7 @@ >> SYM_FUNC_START(__vdso_sgx_enter_enclave) >> /* Prolog */ >> .cfi_startproc >> + ENDBR64 >> push %rbp >> .cfi_adjust_cfa_offset 8 >> .cfi_rel_offset %rbp, 0 >> @@ -62,6 +64,7 @@ SYM_FUNC_START(__vdso_sgx_enter_enclave) >> .Lasync_exit_pointer: >> .Lenclu_eenter_eresume: >> enclu >> + ENDBR64 >> >> /* EEXIT jumps here unless the enclave is doing something fancy. */ >> mov SGX_ENCLAVE_OFFSET_OF_RUN(%rbp), %rbx >> @@ -91,6 +94,7 @@ SYM_FUNC_START(__vdso_sgx_enter_enclave) >> jmp .Lout >> >> .Lhandle_exception: >> + ENDBR64 >> mov SGX_ENCLAVE_OFFSET_OF_RUN(%rbp), %rbx >> >> /* Set the exception info. */ >> -- >> 2.21.0 >> >> > > /Jarkko >
Thanks!
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