[PATCH 03/14] nds32: fix access_ok() checks in get/put_user

Arnd Bergmann
2022-02-14T16:37:08Z

From: Arnd Bergmann <arnd@arndb.de>

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: stable@vger.kernel.org @ v4.19+
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
---
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