Re: [PATCH nf 1/1] netfilter: h323,sip: Fix possible dead loop in nat_rtp_rtcp and nf_nat_sdp_media

Hi,

2017-03-02 15:57 GMT+08:00  [off-list ref]:

From: Gao Feng <redacted>

When h323 and sip try to insert expect nodes, they would increase
the port by 2 for loop, and the loop condition is that "port != 0".
So when the start port is odd number, port never increases to zero.

This seems will never happen, since the RTP port has been ensured to
be even.

For example, at expect_rtp_rtcp():
   ...
   /* RTP port is even */
   rtp_port = port & ~htons(1);
   rtcp_port = port | htons(1);

And at set_expected_rtp_rtcp():
   ...
   base_port = ntohs(tuple.dst.u.udp.port) & ~1;
   rtp_port = htons(base_port);