From d109e9af61a6d2fdf33dc615ab8b724a8e75a8a4 Mon Sep 17 00:00:00 2001 From: Pablo Neira Ayuso Date: Mon, 4 Jun 2012 13:31:04 +0200 Subject: netfilter: nf_ct_h323: fix bug in rtcp natting 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 Signed-off-by: Pablo Neira Ayuso --- net/netfilter/nf_conntrack_h323_main.c | 5 ++--- 1 file changed, 2 insertions(+), 3 deletions(-) (limited to 'net') diff --git a/net/netfilter/nf_conntrack_h323_main.c b/net/netfilter/nf_conntrack_h323_main.c index 46d69d7f1bb4..31f50bc3a312 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 = port | htons(1); /* Create expect for RTP */ if ((rtp_exp = nf_ct_expect_alloc(ct)) == NULL) -- cgit v1.2.3-59-g8ed1b