The mobile core team at @sipgate has disclosed a #SIP parsing bug in #mediatek's #VoLTE/ #VoWifi stack which leads to a null-pointer-dereference and ultimately Denial of Service of VoLTE telephony for the affected devices. Around 40 baseband chips were affected which were deployed to over 1000 devices since 2017.
Thanks to @hendrikkiel for the great cooperation!
Given the recent story about #O2 leaking location information with #VoWiFi #VoLTE
https://mastdatabase.co.uk/blog/2025/05/o2-expose-customer-location-call-4g/
I wonder if @osmocom's project to run VoWiFi with Asterisk and a SIM reader makes this all a lot easier, given you don't need a rooted phone any more.
https://osmocom.org/projects/foss-ims-client/wiki/VoWiFi_with_Asterisk
I've been trying to get it to work on GiffGaff which is a UK O2 Owned/Operated MVO so I'm guessing uses a lot of the same infrastructure.
I haven't got it to work just yet but I'm close.
Got an email from GiffGaff about when the local 3G network (via O2) will be shutdown in August.
I've not found a LTE/4G/5G USB adaptor that works with Asterisk to all us to make calls, but I have been playing @osmocom 's instructions to allow VoWiFi using the SIM to authenticate, but I've not got it work yet. I guess I now have a deadline
https://osmocom.org/projects/foss-ims-client/wiki/VoWiFi_with_Asterisk
OK, so I've got the StrongSwan IPSEC tunnel to connect by moving to Ubuntu.
But I still can't ping the VoIP endpoints (same as with the Python IPSEC), so I assume this is network filtering on the O2/GiffGaff side.
Will fire up the Asterisk port at the weekend and see if I can make a call (might also try my EE SIM)
Kudos to #Tele2 for what looks like the only #IPv6-capable #VoLTE #VoWiFi implementation in #Sweden
Definitely works, confirmed via packet capture :>
OK, having got Nerd Sniped by @sammachin earlier in the week, to try out @osmocom's Asterisk build that adds VoLTE/VoWiFi support https://osmocom.org/news/297
I have received my new USB Smart Card reader (one with a standard sized SIM slot as well)
And have managed to extract the required info from the SIM to find the endpoint for setting up the IPSEC tunnel.
Next step try and create a tunnel
Telefonieren über WLAN (WiFi-Calling/VoWiFi) verbessert die Sprachqualität & Rufaufbau, besonders bei schlechtem Mobilfunkempfang. EVS ("HD Voice Plus") sorgt für kristallklare Gespräche. Prepaid-Kunden können es auch nutzen! 📶 📞 🌐 #WiFiCalling #VoWiFi #Mobilfunk #Heise #lifehack
https://www.heise.de/hintergrund/Telefonieren-per-WiFi-Calling-6003497.html
Curioso tambien en cuanto a #VoWifi de #Telcel - A mi nunca me funcionaba 100% correctamente - estando fuera de area de servicio RAN, no entraban llamadas, pero si funcionaban salientes. Curioso tambien que funcionaban llamantes entrantes mientras ya establecida un llamada (llamada en espera).
Truco: No lo permitían desde el extranjero, pero si se pudo conectar atraves de un VPN con salida en México, esto únicamente cuando primero se selecciona manualmente una red SIN servico de roaming.
Es curioso que #TELCEL haya quitado el servico #VoWifi para sus clientes #prepago.
Según tengo entendido, nunca fue oficialmente soportado aunque sí se pudo activar, pidiéndole en centro de atencion.
¿Será que se valoran mas los recursos del IMS, CPU y ancho de banda que capacidad RAN? Uno lo podria haber dudado.
Hubiera pensado tambien que a #AltanRedes convendría ofrecer el servico VoWifi ya que hay muchas zonas donde esta retado su backhaul, mientras hay bastante #starlink privado.
Jannik
Ben Hardill
Forst
nemo™ 🇺🇦
ludman1
Keith Whyte