From: Al Viro <viro@zeniv.linux.org.uk>
Date: Fri, 9 Sep 2016 23:22:34 +0000 (-0400)
Subject: microblaze: fix copy_from_user()
X-Git-Tag: firefly_0821_release~176^2~4^2~28^2~30
X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=a14f64ca402125152197f14783d97bc1a1e8279f;p=firefly-linux-kernel-4.4.55.git

microblaze: fix copy_from_user()

commit d0cf385160c12abd109746cad1f13e3b3e8b50b8 upstream.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---

diff --git a/arch/microblaze/include/asm/uaccess.h b/arch/microblaze/include/asm/uaccess.h
index 905a9c67f6b8..826676778094 100644
--- a/arch/microblaze/include/asm/uaccess.h
+++ b/arch/microblaze/include/asm/uaccess.h
@@ -373,10 +373,13 @@ extern long __user_bad(void);
 static inline long copy_from_user(void *to,
 		const void __user *from, unsigned long n)
 {
+	unsigned long res = n;
 	might_fault();
-	if (access_ok(VERIFY_READ, from, n))
-		return __copy_from_user(to, from, n);
-	return n;
+	if (likely(access_ok(VERIFY_READ, from, n)))
+		res = __copy_from_user(to, from, n);
+	if (unlikely(res))
+		memset(to + (n - res), 0, res);
+	return res;
 }
 
 #define __copy_to_user(to, from, n)	\