irda: Free skb on irda_accept error path.

BugLink: https://bugs.launchpad.net/bugs/1878232

commit 8ab86c00 upstream.

skb is not freed if newsk is NULL. Rework the error path so free_skb is
unconditionally called on function exit.

Fixes: c3ea9fa2 ("[IrDA] af_irda: IRDA_ASSERT cleanups")
Signed-off-by: Phil Turnbull <phil.turnbull@oracle.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Ian May <ian.may@canonical.com>
Signed-off-by: Kleber Sacilotto de Souza <kleber.souza@canonical.com>

net/irda/af_irda.c

@@ -839,7 +839,7 @@ static int irda_accept(struct socket *sock, struct socket *newsock, int flags)
 	struct sock *sk = sock->sk;
 	struct irda_sock *new, *self = irda_sk(sk);
 	struct sock *newsk;
-	struct sk_buff *skb;
+	struct sk_buff *skb = NULL;
 	int err;
 
 	err = irda_create(sock_net(sk), newsock, sk->sk_protocol, 0);
@@ -907,7 +907,6 @@ static int irda_accept(struct socket *sock, struct socket *newsock, int flags)
 	err = -EPERM; /* value does not seem to make sense. -arnd */
 	if (!new->tsap) {
 		pr_debug("%s(), dup failed!\n", __func__);
-		kfree_skb(skb);
 		goto out;
 	}
 
@@ -926,7 +925,6 @@ static int irda_accept(struct socket *sock, struct socket *newsock, int flags)
 	/* Clean up the original one to keep it in listen state */
 	irttp_listen(self->tsap);
 
-	kfree_skb(skb);
 	sk->sk_ack_backlog--;
 
 	newsock->state = SS_CONNECTED;
@@ -934,6 +932,7 @@ static int irda_accept(struct socket *sock, struct socket *newsock, int flags)
 	irda_connect_response(new);
 	err = 0;
 out:
+	kfree_skb(skb);
 	release_sock(sk);
 	return err;
 }