L5 && cell broadcast message

An hour ago all the cellphones in my office were having a loud alarm and a message on the screen, that this was only a test alarm and more information about this could be found on the URL … I wanted to take a photo with my L5 on some other device, but the message moved away from the screen when I unlocked the other device and was not stored in the normal messages.

Only my L5 was silent, no alarm and no message.

Could be related to: VoLTE support progress

So could depend on whether you have VoLTE enabled and working, and whether you have enabled CBS, and whether you have all the latest patches, and what firmware version you have on the modem.

Nevertheless, based on earlier discussions, many people would consider the lack of cell broadcasts a ‘feature’. :wink:

(This must be a pig of a feature to test, during development, since you can’t exactly get these broadcasts on demand. Or maybe there is some way of getting a broadcast message directed to a single device?)

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Today it’s “Warntag” in NRW, Germany. At 11 o’ clock sirens went up, internet based warning systems like “Nina” sent messages to App users and CBS broadcasted the warnings, too. At least that’s what should have happend.

I don’t see a relation to VoLTE. Although I can’t exclude totally. CBS was started in GSM-only days, as far as I remember. Not sure how it was carried over to LTE.

AFAIK CBS hasn’t been used for several years in Germany. And now the system had to be reestablished.

For CBS testing I guess it’s broadcasting by definition. Maybe you can use cell tower devices for connection with your test devices.

Here is the message on my company iPhone

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Chatty: https://source.puri.sm/Librem5/chatty/-/issues/513

ModemManager: https://gitlab.freedesktop.org/mobile-broadband/ModemManager/-/issues/253

Old forum thread: Receiving emergency calls/messages

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Totally. It was partly about whether it needs to be implemented twice or debugged twice or tested twice (once for VoLTE and once before VoLTE) - and the work hasn’t been done for either or hasn’t been done for both.

Also, the fact that enabling CBS is on the tool that people are using to enable VoLTE could mean that if you have no interest in VoLTE then you haven’t downloaded the tool, you haven’t enabled CBS (and you can’t enable CBS otherwise) … so CBS won’t be working for you. But that depends on whether CBS is enabled by default.

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Screenshot here.


Here in the US, there are federal laws that require cell phone providers to lock the phone owner out of being able to disable some types of emergency alerts. Those alerts don’t come in via ordinary SMS. It’s a different protocol. With an opensource phone, it wouldn’t be productive for Purism to ship the phone with that feature locked. Too many Librem 5 owners would change the source code to add or enable that toggle switch (which is greyed-out in Android), recompile the operating system, and upload it to the phone. Then you could turn those alerts off. I doubt that Purism even includes those emergency alerts in the PureOS operating system.

Unless you want those alerts, they are not there for your benefit. They are there to benefit others who have deemed that you need to have the information, whether or not you want it. If they leave that toggle switch functional so I have an opportunity to turn it off, I’ll consider maybe leaving it turned on. If it is greyed-out or doesn’t exist (forcing me to receive alerts I didn’t sign up for), then I want it turned off, as a matter of principle.


You just have the wrong android.

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Graphene OS? Like mine

Calyx OS. .


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Do you want your Librem 5 be unsecurity by goverments like others devices does as iphones or android phones? not all features in android mean can be good for Librem 5, if you like android/iphone things then these devices are you, sometime things can not be mixed.

Now I’m curious… What’s insecure about receiving alert messages?

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Enabling receiving-alert-messages it enable backdoors for goverments too, as far i know.
Also i understanding that enabling this alert-message it could save our lives from an earthquake or sutnami, but governments have taken advantage of this features to got them surveillance permission from us by enabling this type of message.

I don’t see how government/public-safety messages that are broadcast to a group of phone numbers in a certain region could open up backdoors or enable surveillance of the recipients. Can you provide any references for that?

One thing I can think of that could compromise a device is, say, a spoofed public alert from miscreants, if the message contains a link to malware. (EDIT: But then that’s true of any message received from anyone.)

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I’ve reported only a fact, that my L5 did not received or showed the CBM. For the rest, I’m not keen on receiving such CBM.

Me disculpo entonces.

Aceptado. Gracias.

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Let’s say we are talking hypothetical here … the receipt of any message could open up a backdoor if it exploits a vulnerability e.g. some deliberately malformed message or e.g. some unhandled data value or e.g. buffer overflow exploit or e.g. you get the idea.

A true cell broadcast wouldn’t be great for this exploit since it is untargeted. (It would however be great if being used by random miscreants i.e. with one broadcast, identify all exploitable devices.) However, you can’t really be sure that a broadcast is a broadcast unless you are able to confer with other users. (That would seem to apply here for @guru i.e. able to confer and, the one time I was in a cell that received such an alert, it applied to me too i.e. a number of people in a room, with one phone per person.)

I think most of us agree that the Librem 5 should have the capability to receive such alerts and the user should have the capability to switch those alerts off (as far as actually alerting the user). I am not sure that the work has been done to make the first part of that true.

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