Commit 2a5b8275 authored Oct 01, 2008 by Denis V. Lunev Committed by David S. Miller Oct 01, 2008

ipv6: NULL pointer dereferrence in tcp_v6_send_ack



The following actions are possible:
tcp_v6_rcv
  skb->dev = NULL;
  tcp_v6_do_rcv
    tcp_v6_hnd_req
      tcp_check_req
        req->rsk_ops->send_ack == tcp_v6_send_ack

So, skb->dev can be NULL in tcp_v6_send_ack. We must obtain namespace
from dst entry.

Thanks to Vitaliy Gusev <vgusev@openvz.org> for initial problem finding
in IPv4 code.

Signed-off-by: Denis V. Lunev <den@openvz.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

parent 4dd7972d

net/ipv6/tcp_ipv6.c

+1 −1

Original line number	Diff line number	Diff line
		@@ -1050,7 +1050,7 @@ static void tcp_v6_send_ack(struct sk_buff *skb, u32 seq, u32 ack, u32 win, u32
		struct tcphdr th = tcp_hdr(skb), t1;
		struct sk_buff *buff;
		struct flowi fl;
		struct net *net = dev_net(skb->dev);
		struct net *net = dev_net(skb->dst->dev);
		struct sock *ctl_sk = net->ipv6.tcp_sk;
		unsigned int tot_len = sizeof(struct tcphdr);
		__be32 *topt;