[PATCH 3.2 118/152] score: fix copy_from_user() and friends

[Ben Hutchings]

3.2.84-rc1 review patch.  If anyone has any objections, please let me know.

------------------

From: Al Viro <v...@zeniv.linux.org.uk>

commit b615e3c74621e06cd97f86373ca90d43d6d998aa upstream.

Signed-off-by: Al Viro <v...@zeniv.linux.org.uk>
Signed-off-by: Ben Hutchings <b...@decadent.org.uk>
---
 arch/score/include/asm/uaccess.h | 41 ++++++++++++++++++++--------------------
 1 file changed, 20 insertions(+), 21 deletions(-)

--- a/arch/score/include/asm/uaccess.h
+++ b/arch/score/include/asm/uaccess.h
@@ -296,35 +296,34 @@ extern int __copy_tofrom_user(void *to,
 static inline unsigned long
 copy_from_user(void *to, const void *from, unsigned long len)
 {
-       unsigned long over;
+       unsigned long res = len;
 
-       if (access_ok(VERIFY_READ, from, len))
-               return __copy_tofrom_user(to, from, len);
+       if (likely(access_ok(VERIFY_READ, from, len)))
+               res = __copy_tofrom_user(to, from, len);
 
-       if ((unsigned long)from < TASK_SIZE) {
-               over = (unsigned long)from + len - TASK_SIZE;
-               return __copy_tofrom_user(to, from, len - over) + over;
-       }
-       return len;
+       if (unlikely(res))
+               memset(to + (len - res), 0, res);
+
+       return res;
 }
 
 static inline unsigned long
 copy_to_user(void *to, const void *from, unsigned long len)
 {
-       unsigned long over;
-
-       if (access_ok(VERIFY_WRITE, to, len))
-               return __copy_tofrom_user(to, from, len);
+       if (likely(access_ok(VERIFY_WRITE, to, len)))
+               len = __copy_tofrom_user(to, from, len);
 
-       if ((unsigned long)to < TASK_SIZE) {
-               over = (unsigned long)to + len - TASK_SIZE;
-               return __copy_tofrom_user(to, from, len - over) + over;
-       }
        return len;
 }
 
-#define __copy_from_user(to, from, len)        \
-               __copy_tofrom_user((to), (from), (len))
+static inline unsigned long
+__copy_from_user(void *to, const void *from, unsigned long len)
+{
+       unsigned long left = __copy_tofrom_user(to, from, len);
+       if (unlikely(left))
+               memset(to + (len - left), 0, left);
+       return left;
+}
 
 #define __copy_to_user(to, from, len)          \
                __copy_tofrom_user((to), (from), (len))
@@ -338,17 +337,17 @@ __copy_to_user_inatomic(void *to, const
 static inline unsigned long
 __copy_from_user_inatomic(void *to, const void *from, unsigned long len)
 {
-       return __copy_from_user(to, from, len);
+       return __copy_tofrom_user(to, from, len);
 }
 
-#define __copy_in_user(to, from, len)  __copy_from_user(to, from, len)
+#define __copy_in_user(to, from, len)  __copy_tofrom_user(to, from, len)
 
 static inline unsigned long
 copy_in_user(void *to, const void *from, unsigned long len)
 {
        if (access_ok(VERIFY_READ, from, len) &&
                      access_ok(VERFITY_WRITE, to, len))
-               return copy_from_user(to, from, len);
+               return __copy_tofrom_user(to, from, len);
 }
 
 /*