net: qrtr: fix memort leak in qrtr_tun_write_iter

commit a21b7f0c upstream.

In qrtr_tun_write_iter the allocated kbuf should be release in case of
error or success return.

v2 Update: Thanks to David Miller for pointing out the release on success
path as well.
Signed-off-by: Navid Emamdoost <navid.emamdoost@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Cc: Ben Hutchings <ben@decadent.org.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

net/qrtr/tun.c

@@ -84,11 +84,14 @@ static ssize_t qrtr_tun_write_iter(struct kiocb *iocb, struct iov_iter *from)
 	if (!kbuf)
 		return -ENOMEM;
 
-	if (!copy_from_iter_full(kbuf, len, from))
+	if (!copy_from_iter_full(kbuf, len, from)) {
+		kfree(kbuf);
 		return -EFAULT;
+	}
 
 	ret = qrtr_endpoint_post(&tun->ep, kbuf, len);
 
+	kfree(kbuf);
 	return ret < 0 ? ret : len;
 }