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 <jagdish.motwani@elitecore.com> Signed-off-by: Sanket Shah <sanket.shah@elitecore.com> Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
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@ -270,9 +270,8 @@ static int expect_rtp_rtcp(struct sk_buff *skb, struct nf_conn *ct,
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return 0;
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return 0;
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/* RTP port is even */
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/* RTP port is even */
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port &= htons(~1);
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rtp_port = port & ~htons(1);
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rtp_port = port;
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rtcp_port = port | htons(1);
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rtcp_port = htons(ntohs(port) + 1);
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/* Create expect for RTP */
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/* Create expect for RTP */
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if ((rtp_exp = nf_ct_expect_alloc(ct)) == NULL)
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if ((rtp_exp = nf_ct_expect_alloc(ct)) == NULL)
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