Subject: [PATCH v2 03/18] nds32: fix access_ok() checks in get/put_user

From: Arnd Bergmann <[email-masked]>
Date: Wed, 16 Feb 2022 14:13:17 +0100

From: Arnd Bergmann <[email-masked]>

The get_user()/put_user() functions are meant to check for
access_ok(), while the __get_user()/__put_user() functions
don't.

This broke in 4.19 for nds32, when it gained an extraneous
check in __get_user(), but lost the check it needs in
__put_user().

Fixes: 487913ab18c2 ("nds32: Extract the checking and getting pointer to a macro")
Cc: [email-masked] @ v4.19+
Signed-off-by: Arnd Bergmann <[email-masked]>
---
 arch/nds32/include/asm/uaccess.h | 22 +++++++++++++++++-----
 1 file changed, 17 insertions(+), 5 deletions(-)

diff --git a/arch/nds32/include/asm/uaccess.h b/arch/nds32/include/asm/uaccess.h
index d4cbf069dc22..37a40981deb3 100644
--- a/arch/nds32/include/asm/uaccess.h
+++ b/arch/nds32/include/asm/uaccess.h
@@ -70,9 +70,7 @@ static inline void set_fs(mm_segment_t fs)
  * versions are void (ie, don't return a value as such).
  */
 
-#define get_user	__get_user					\
-
-#define __get_user(x, ptr)						\
+#define get_user(x, ptr)						\
 ({									\
 	long __gu_err = 0;						\
 	__get_user_check((x), (ptr), __gu_err);				\
@@ -85,6 +83,14 @@ static inline void set_fs(mm_segment_t fs)
 	(void)0;							\
 })
 
+#define __get_user(x, ptr)						\
+({									\
+	long __gu_err = 0;						\
+	const __typeof__(*(ptr)) __user *__p = (ptr);			\
+	__get_user_err((x), __p, (__gu_err));				\
+	__gu_err;							\
+})
+
 #define __get_user_check(x, ptr, err)					\
 ({									\
 	const __typeof__(*(ptr)) __user *__p = (ptr);			\
@@ -165,12 +171,18 @@ do {									\
 		: "r"(addr), "i"(-EFAULT)				\
 		: "cc")
 
-#define put_user	__put_user					\
+#define put_user(x, ptr)						\
+({									\
+	long __pu_err = 0;						\
+	__put_user_check((x), (ptr), __pu_err);				\
+	__pu_err;							\
+})
 
 #define __put_user(x, ptr)						\
 ({									\
 	long __pu_err = 0;						\
-	__put_user_err((x), (ptr), __pu_err);				\
+	__typeof__(*(ptr)) __user *__p = (ptr);				\
+	__put_user_err((x), __p, __pu_err);				\
 	__pu_err;							\
 })
 
-- 
2.29.2