[PATCH v25 9/9] x86/vdso: Add ENDBR to __vdso_sgx_enter_enclave

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



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@xxxxxxxxx>
Cc: Andy Lutomirski <luto@xxxxxxxxxx>
Cc: Borislav Petkov <bp@xxxxxxxxx>
Cc: Dave Hansen <dave.hansen@xxxxxxxxxxxxxxx>
Cc: Jarkko Sakkinen <jarkko@xxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
---
 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 86a0e94f68df..f3ebd38d1898 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




[Index of Archives]     [Kernel Newbies]     [Security]     [Netfilter]     [Bugtraq]     [Linux FS]     [Yosemite Forum]     [MIPS Linux]     [ARM Linux]     [Linux Security]     [Linux RAID]     [Samba]     [Video 4 Linux]     [Device Mapper]     [Linux Resources]

  Powered by Linux