nios2: copy_from_user() should zero the tail of destination

Cc: stable@vger.kernel.org
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
This commit is contained in:
Al Viro 2016-08-20 16:36:36 -04:00
parent ae7cc577ec
commit e33d1f6f72

View file

@ -102,9 +102,12 @@ extern long __copy_to_user(void __user *to, const void *from, unsigned long n);
static inline long copy_from_user(void *to, const void __user *from,
unsigned long n)
{
if (!access_ok(VERIFY_READ, from, n))
return n;
return __copy_from_user(to, from, n);
unsigned long res = n;
if (access_ok(VERIFY_READ, from, n))
res = __copy_from_user(to, from, n);
if (unlikely(res))
memset(to + (n - res), 0, res);
return res;
}
static inline long copy_to_user(void __user *to, const void *from,