Bug#902598: siproxd: Sends replies to wrong address

[Paul Chitescu]

Hello!

Are you sure it's a bug?

The SIP standard states that the reply should be sent to the topmost Via
address, in this case:

  Via: SIP/2.0/UDP 213.95.149.23:5060;branch=z9hG4bK45607d54

Some applications and in particular VoLTE require that the Via address
to be honored.
Of course that breaks NAT traversal - but the SIP standard was written
well before that became common.

Some additional info: http://babel.de/art20080317a.html

Paul Chitescu


On 06/28/2018 12:00 PM, Matthias Urlichs via Pkg-voip-maintainers wrote:
> Package: siproxd
> Version: 1:0.8.1-4.1
> Severity: important
>
> siproxy sends SIP registration replies to the wrong address.
>
> Specifically, this hostname couldn't be resolved, thus the REGISTER is
> rejected:
>
> [pid 10545] recvfrom(4, "REGISTER sip:pbx1 SIP/2.0\r\nVia: SIP/2.0/UDP 213.95.149.23:5060;branch=z9hG4bK45607d54\r\nMax-Forwards: 70\r\nFrom: <sip:SmurfAsterisk at pbx1.noris.net>;tag=as323b8169\r\nTo: <sip:SmurfAsterisk at pbx1.noris.net>\r\nCall-ID: 14f44c1b7facb9c843d3b30d046503a1 at 127.0.1.1\r\nCSeq: 152 REGISTER\r\nSupported: replaces, timer\r\nUser-Agent: Smurf-O-Asterisk\r\nExpires: 120\r\nContact: <sip:1717 at 213.95.149.23:5060>\r\nContent-Length: 0\r\n\r\n", 8195, 0, {sa_family=AF_INET, sin_port=htons(5060), sin_addr=inet_addr("10.107.8.134")}, [16]) = 408
> [pid 10545] sendto(4, "SIP/2.0 408 Request Timeout\r\nVia: SIP/2.0/UDP 213.95.149.23:5060;branch=z9hG4bK45607d54\r\nFrom: <sip:SmurfAsterisk at pbx1.noris.net>;tag=as323b8169\r\nTo: <sip:SmurfAsterisk at pbx1.noris.net>\r\nCall-ID: 14f44c1b7facb9c843d3b30d046503a1 at 127.0.1.1\r\nCSeq: 152 REGISTER\r\nContent-Length: 0\r\n\r\n", 280, 0, {sa_family=AF_INET, sin_port=htons(5060), sin_addr=inet_addr("213.95.149.23")}, 16) = 280
>
> SIP states that INVITEs et al. shall go to the address named in
> the Contact: header. This however is not an INVITE but a reply to
> a registration attempt. It needs to be sent to the host+port which
> transmitted the original request.
>
> -- System Information:
> Debian Release: buster/sid
>   APT prefers testing
>   APT policy: (750, 'testing'), (700, 'stable'), (600, 'unstable'), (550, 'experimental')
> Architecture: amd64 (x86_64)
> Foreign Architectures: i386
>
> Kernel: Linux 4.13.0-1-amd64 (SMP w/1 CPU core)
> Locale: LANG=en_US.UTF-8, LC_CTYPE=en_US.UTF-8 (charmap=UTF-8), LANGUAGE=en_US.UTF-8 (charmap=UTF-8)
> Shell: /bin/sh linked to /bin/dash
> Init: systemd (via /run/systemd/system)
>
> Versions of packages siproxd depends on:
> ii  adduser      3.117
> ii  libc6        2.27-3
> ii  libltdl7     2.4.6-2.1
> pn  libosip2-11  <none>
>
> siproxd recommends no packages.
>
> siproxd suggests no packages.