irda: do not leak initialized list.dev to userspace

BugLink: http://bugs.launchpad.net/bugs/1714298

[ Upstream commit b024d949 ]

list.dev has not been initialized and so the copy_to_user is copying
data from the stack back to user space which is a potential
information leak. Fix this ensuring all of list is initialized to
zero.

Detected by CoverityScan, CID#1357894 ("Uninitialized scalar variable")
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Stefan Bader <stefan.bader@canonical.com>
Signed-off-by: Kleber Sacilotto de Souza <kleber.souza@canonical.com>

net/irda/af_irda.c

@@ -2227,7 +2227,7 @@ static int irda_getsockopt(struct socket *sock, int level, int optname,
 {
 	struct sock *sk = sock->sk;
 	struct irda_sock *self = irda_sk(sk);
-	struct irda_device_list list;
+	struct irda_device_list list = { 0 };
 	struct irda_device_info *discoveries;
 	struct irda_ias_set *	ias_opt;	/* IAS get/query params */
 	struct ias_object *	ias_obj;	/* Object in IAS */