[PATCH v24 8/9] x86/vdso/32: Add ENDBR to __kernel_vsyscall entry point
From: Yu-cheng Yu <hidden>
Date: 2021-04-01 22:14:45
Also in:
linux-api, linux-arch, linux-mm, lkml
Subsystem:
the rest, x86 architecture (32-bit and 64-bit), x86 entry code, x86 vdso · Maintainers:
Linus Torvalds, Thomas Gleixner, Ingo Molnar, Borislav Petkov, Dave Hansen, Andy Lutomirski
From: "H.J. Lu" <redacted> 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 that to __kernel_vsyscall entry point. Signed-off-by: H.J. Lu <redacted> Signed-off-by: Yu-cheng Yu <redacted> Cc: Andy Lutomirski <luto@kernel.org> Cc: Kees Cook <redacted> --- arch/x86/entry/vdso/vdso32/system_call.S | 2 ++ 1 file changed, 2 insertions(+)
diff --git a/arch/x86/entry/vdso/vdso32/system_call.S b/arch/x86/entry/vdso/vdso32/system_call.S
index de1fff7188aa..c962e7e4f7e3 100644
--- a/arch/x86/entry/vdso/vdso32/system_call.S
+++ b/arch/x86/entry/vdso/vdso32/system_call.S@@ -7,6 +7,7 @@ #include <asm/dwarf2.h> #include <asm/cpufeatures.h> #include <asm/alternative-asm.h> +#include <asm/vdso.h> .text .globl __kernel_vsyscall
@@ -14,6 +15,7 @@ ALIGN __kernel_vsyscall: CFI_STARTPROC + ENDBR /* * Reshuffle regs so that all of any of the entry instructions * will preserve enough state.
--
2.21.0