metag: copy_from_user() should zero the destination on access_ok() failure

Cc: stable@vger.kernel.org
Acked-by: James Hogan <james.hogan@imgtec.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

1 files changed, 2 insertions, 1 deletions

diff --git a/arch/metag/include/asm/uaccess.h b/arch/metag/include/asm/uaccess.h
index 8282cbce7e39..273e61225c27 100644
--- a/arch/metag/include/asm/uaccess.h
+++ b/arch/metag/include/asm/uaccess.h
@@ -204,8 +204,9 @@ extern unsigned long __must_check __copy_user_zeroing(void *to,
 static inline unsigned long
 copy_from_user(void *to, const void __user *from, unsigned long n)
 {
-        if (access_ok(VERIFY_READ, from, n))
+        if (likely(access_ok(VERIFY_READ, from, n)))
                 return __copy_user_zeroing(to, from, n);
+        memset(to, 0, n);
         return n;
 }