[PATCH 4.7 168/184] sh: fix copy_from_user()

From: Greg Kroah-Hartman
Date: Thu Sep 22 2016 - 13:58:44 EST


4.7-stable review patch. If anyone has any objections, please let me know.

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

From: Al Viro <viro@xxxxxxxxxxxxxxxxxx>

commit 6e050503a150b2126620c1a1e9b3a368fcd51eac upstream.

Signed-off-by: Al Viro <viro@xxxxxxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
arch/sh/include/asm/uaccess.h | 5 ++++-
1 file changed, 4 insertions(+), 1 deletion(-)

--- a/arch/sh/include/asm/uaccess.h
+++ b/arch/sh/include/asm/uaccess.h
@@ -151,7 +151,10 @@ copy_from_user(void *to, const void __us
__kernel_size_t __copy_size = (__kernel_size_t) n;

if (__copy_size && __access_ok(__copy_from, __copy_size))
- return __copy_user(to, from, __copy_size);
+ __copy_size = __copy_user(to, from, __copy_size);
+
+ if (unlikely(__copy_size))
+ memset(to + (n - __copy_size), 0, __copy_size);

return __copy_size;
}