From patchwork Tue May 22 06:00:27 2012 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Subject: netfilter conntrack helper: nf_ct_h323: fix bug in rtcp natting Date: Mon, 21 May 2012 20:00:27 -0000 From: Jagdish Motwani X-Patchwork-Id: 160542 Message-Id: <4FBB2B7B.6060907@elitecore.com> To: 'Patrick McHardy' Cc: netfilter-devel@vger.kernel.org The nat_rtp_rtcp hook takes two separate parameters port and rtp_port. port is expected to be the real h245 address(found inside the packet). rtp_port is the even number closest to port (RTP ports are even and RTCP ports are odd) However currently, both port and rtp_port are having same value(both are rounded to nearest even numbers). This works well in case of openlogicalchannel with media (RTP/even) port. But in case of openlogicalchannel for media control (RTCP/odd) port, h245 address in the packet is wrongly modified to have an even port. I am attaching a pcap demonstrating the problem, for any further analysis. This behavior was introduced around v2.6.19 while rewriting the helper. Signed-off-by: Jagdish Motwani Signed-off-by: Sanket Shah --- if ((rtp_exp = nf_ct_expect_alloc(ct)) == NULL) diff --git a/net/netfilter/nf_conntrack_h323_main.c b/net/netfilter/nf_conntrack_h323_main.c index 46d69d7..7f0de36 100644 --- a/net/netfilter/nf_conntrack_h323_main.c +++ b/net/netfilter/nf_conntrack_h323_main.c @@ -270,9 +270,8 @@ static int expect_rtp_rtcp(struct sk_buff *skb, struct nf_conn *ct, return 0; /* RTP port is even */ - port &= htons(~1); - rtp_port = port; - rtcp_port = htons(ntohs(port) + 1); + rtp_port = port & htons(~1); + rtcp_port = htons(ntohs(rtp_port) + 1); /* Create expect for RTP */