From 58ac3154b83938515129c20aa76d456a4c9202a8 Mon Sep 17 00:00:00 2001
From: Kees Cook <keescook@chromium.org>
Date: Fri, 26 Jun 2020 13:34:25 -0700
Subject: [PATCH] x86/entry: Actually disable stack protector
Some builds of GCC enable stack protector by default. Simply removing
the arguments is not sufficient to disable stack protector, as the stack
protector for those GCC builds must be explicitly disabled. Remove the
argument removals and add -fno-stack-protector. Additionally include
missed x32 argument updates, and adjust whitespace for readability.
Fixes: 20355e5f73a7 ("x86/entry: Exclude low level entry code from sanitizing")
Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lkml.kernel.org/r/202006261333.585319CA6B@keescook
---
arch/x86/entry/Makefile | 14 +++++++++++---
1 file changed, 11 insertions(+), 3 deletions(-)
diff --git a/arch/x86/entry/Makefile b/arch/x86/entry/Makefile
index b7a5790d8d63e4..08bf95dbc91126 100644
--- a/arch/x86/entry/Makefile
+++ b/arch/x86/entry/Makefile
@@ -7,12 +7,20 @@ KASAN_SANITIZE := n
UBSAN_SANITIZE := n
KCOV_INSTRUMENT := n
-CFLAGS_REMOVE_common.o = $(CC_FLAGS_FTRACE) -fstack-protector -fstack-protector-strong
-CFLAGS_REMOVE_syscall_32.o = $(CC_FLAGS_FTRACE) -fstack-protector -fstack-protector-strong
-CFLAGS_REMOVE_syscall_64.o = $(CC_FLAGS_FTRACE) -fstack-protector -fstack-protector-strong
+CFLAGS_REMOVE_common.o = $(CC_FLAGS_FTRACE)
+CFLAGS_REMOVE_syscall_64.o = $(CC_FLAGS_FTRACE)
+CFLAGS_REMOVE_syscall_32.o = $(CC_FLAGS_FTRACE)
+CFLAGS_REMOVE_syscall_x32.o = $(CC_FLAGS_FTRACE)
+
+CFLAGS_common.o += -fno-stack-protector
+CFLAGS_syscall_64.o += -fno-stack-protector
+CFLAGS_syscall_32.o += -fno-stack-protector
+CFLAGS_syscall_x32.o += -fno-stack-protector
CFLAGS_syscall_64.o += $(call cc-option,-Wno-override-init,)
CFLAGS_syscall_32.o += $(call cc-option,-Wno-override-init,)
+CFLAGS_syscall_x32.o += $(call cc-option,-Wno-override-init,)
+
obj-y := entry_$(BITS).o thunk_$(BITS).o syscall_$(BITS).o
obj-y += common.o
--
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