[PATCH 4.19 31/75] s390/kasan: fix strncpy_from_user kasan checks

From: Greg Kroah-Hartman
Date: Mon Jun 17 2019 - 17:32:21 EST

[ Upstream commit 01eb42afb45719cb41bb32c278e068073738899d ]

arch/s390/lib/uaccess.c is built without kasan instrumentation. Kasan
checks are performed explicitly in copy_from_user/copy_to_user
functions. But since those functions could be inlined, calls from
files like uaccess.c with instrumentation disabled won't generate
kasan reports. This is currently the case with strncpy_from_user
function which was revealed by newly added kasan test. Avoid inlining of
copy_from_user/copy_to_user when the kernel is built with kasan support
to make sure kasan checks are fully functional.

Signed-off-by: Vasily Gorbik <gor@xxxxxxxxxxxxx>
Signed-off-by: Martin Schwidefsky <schwidefsky@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
arch/s390/include/asm/uaccess.h | 2 ++
1 file changed, 2 insertions(+)

diff --git a/arch/s390/include/asm/uaccess.h b/arch/s390/include/asm/uaccess.h
index ad6b91013a05..5332f628c1ed 100644
--- a/arch/s390/include/asm/uaccess.h
+++ b/arch/s390/include/asm/uaccess.h
@@ -56,8 +56,10 @@ raw_copy_from_user(void *to, const void __user *from, unsigned long n);
unsigned long __must_check
raw_copy_to_user(void __user *to, const void *from, unsigned long n);