[IPV6]: inet_sk(sk)->cork.opt leak

IPv6 UDP sockets wth IPv4 mapped address use udp_sendmsg to send the data
actually. In this case ip_flush_pending_frames should be called instead
of ip6_flush_pending_frames.
Signed-off-by: Denis V. Lunev <den@openvz.org>
Signed-off-by: YOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org>

include/net/udp.h

@@ -135,6 +135,7 @@ extern void	udp_err(struct sk_buff *, u32);
 
 extern int	udp_sendmsg(struct kiocb *iocb, struct sock *sk,
 			    struct msghdr *msg, size_t len);
+extern void	udp_flush_pending_frames(struct sock *sk);
 
 extern int	udp_rcv(struct sk_buff *skb);
 extern int	udp_ioctl(struct sock *sk, int cmd, unsigned long arg);

net/ipv4/udp.c

@@ -420,7 +420,7 @@ void udp_err(struct sk_buff *skb, u32 info)
 /*
  * Throw away all pending data and cancel the corking. Socket is locked.
  */
-static void udp_flush_pending_frames(struct sock *sk)
+void udp_flush_pending_frames(struct sock *sk)
 {
 	struct udp_sock *up = udp_sk(sk);
 
@@ -430,6 +430,7 @@ static void udp_flush_pending_frames(struct sock *sk)
 		ip_flush_pending_frames(sk);
 	}
 }
+EXPORT_SYMBOL(udp_flush_pending_frames);
 
 /**
  * 	udp4_hwcsum_outgoing  -  handle outgoing HW checksumming

net/ipv6/udp.c

@@ -534,7 +534,9 @@ static void udp_v6_flush_pending_frames(struct sock *sk)
 {
 	struct udp_sock *up = udp_sk(sk);
 
-	if (up->pending) {
+	if (up->pending == AF_INET)
+		udp_flush_pending_frames(sk);
+	else if (up->pending) {
 		up->len = 0;
 		up->pending = 0;
 		ip6_flush_pending_frames(sk);