The copy_to_user() function returns the number of bytes remaining to be
copied.  In this code, that positive return is checked at the end of the
function and we return zero/success.  What we should do instead is
return -EFAULT.
Fixes: a7b4f989a629 ("netfilter: ipset: IP set core support")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Jozsef Kadlecsik <kadlec@netfilter.org>
                }
 
                req_version->version = IPSET_PROTOCOL;
-               ret = copy_to_user(user, req_version,
-                                  sizeof(struct ip_set_req_version));
+               if (copy_to_user(user, req_version,
+                                sizeof(struct ip_set_req_version)))
+                       ret = -EFAULT;
                goto done;
        }
        case IP_SET_OP_GET_BYNAME: {
        }       /* end of switch(op) */
 
 copy:
-       ret = copy_to_user(user, data, copylen);
+       if (copy_to_user(user, data, copylen))
+               ret = -EFAULT;
 
 done:
        vfree(data);