"Say why you called" in stocke dialler always send SMS texts

7cwt

New to GrapheneOS on Pixel 9 Pro XL in Australia - letting people know of a CallerID leak on the stock phone app.

I recently set the phone up to hide all CallerID except for those I had appended an 'unhide' code in my address book. I was using the stock phone, messages and contact apps with no changes to default permissions (as I'd read was recommended for stock apps, especially for newbies like me).

On testing, I found that for calls I made to any (un-appended/Hide CallerID) number that were not completed (e.g., I hung up after a couple of rings) I got a prompt offering to send a text to 'Say why you called'. I found this link for 'say why you called' https://www.apkmirror.com/apk/google-inc/google-phone/google-phone-12-0-167196395-release/

Even though I never responded to this prompt (e.g., by dismissing or just closing the app) the stock phone app always sent a text that (in Australia at least) reveals the caller's phone number to the dialed mobile regardless of all other CallerID settings being set to hide. No idea if people on plans that charge per SMS wear this cost (such as when roaming).

Turning off the messages permissions in the stock phone app solves the problem (you can still text via the messages app), but I have since switched to Fossify apps to avoid this completely.

This might be a handy feature for some, but in my view, users should have the choice about whether a text is actually sent, particularly if it will always reveal your number, such as for a short mis-dial .

Hope that helps others, or happy for the community to let me know if I have gotten something wrong.

de0u

7cwt Even though I never responded to this prompt (e.g., by dismissing or just closing the app) the stock phone app always sent a text that (in Australia at least) reveals the caller's phone number to the dialed mobile regardless of all other CallerID settings being set to hide.

What did the message say?

Murcielago

7cwt

Thanks for the info, one should take that into account if not revealing your phone number is part of your threat model.

I have just tested it on my carrier - here “say why you called” works as expected/desired: If you ignore the popup or press “send” and cancel the following dialog (in which you can enter text modules or individual text), no message is sent.

Out of curiosity: What permission must be revoked from the app to prevent automatic sending?

de0u

7cwt The recipient got the message "<my number> called. No Voicemail message was left. For more information on this feature, free call 147 from your mobile phone."

That sounds very much like a carrier feature, not like a GrapheneOS feature. Searching for the "For more information..." sentence turns up results like this one: https://www.optus.com.au/enterprise/webex-contact-centre-provider/calling-and-messaging/missed-call-services

7cwt Turning off the messages permissions in the stock phone app solves the problem (you can still text via the messages app), but I have since switched to Fossify apps to avoid this completely.

If that works, I would suspect that a "SIM Toolkit" applet is involved. Are you willing to indicate which carrier you are using? Do you know if recipients of your calls were also using that carrier?

byteigcart

Hi, okay so I just want to confirm, you're not using a stock app if you've installed googles dialer (phone by google)? That prompt would not appear from within stock dialer on Graphene OS to the best of my knowledge.

7cwt

I may have inadvertently led you to think that with the link I provided, but no, definitely only the stock GrapheneOS phone app.

7cwt

de0u the recipient got the message "<my number> called. No Voicemail message was left. For more information on this feature, free call 147 from your mobile phone."

7cwt

Murcielago I turned off the SMS permission in the default phone app and that SEEMED to fix it. But as the problem is now not occurring today...I can no longer be sure that was the real issue.

7cwt

Thanks for your questions. They have prompted me to retest today with the recipient having my number/not having my number as well as wifi calling/network calling. (I wondered if it was a network message) I can't replicate the problem that was happening yesterday (so that's embarrassing).
One thought is there is some delay with the telco in updating the CallerID status...but I'm no engineer, so take that with a grain of salt. Perhaps the most likely explanation is the simplest - user error?!
I am trying not to use SMS as a rule, so the idea of the app doing as accused annoyed me...hopefully not an issue.

de0u

7cwt I turned off the SMS permission in the default phone app and that SEEMED to fix it. But as the problem is now not occurring today...I can no longer be sure that was the real issue.

Honestly I suspect those messages were generated by the carrier of the people you called, not by anything on your device.

7cwt

de0u We are both using the Telstra network as it happens. I guess if that is where the delay could be it would be of interest to people who perhaps flip CallerID on and off expecting it to be immediate...so arguably an edge case.
My confidence in the stock apps bundled with GrapheneOS goes up again... (And I can't speak highly enough of GrapheneOS anyway)