(Location) Altitude and satellite data leaks

[micolous]

At present in applications for which XPrivacy has revoked access to location information, the fix data from the phone is used to randomize a fixed location (by default, Christmas Island). As part of this, the real altitude information from a 3D GPS fix is passed to applications.

Additionally, GpsSatellite information seems to leak through to applications unaltered, which may allow retrieval of position (given known orbit data and time).

Satellite positions and altitude can be seen in the GPS Status and Toolbox application, even when location access is revoked by XPrivacy.

[M66B]

How would you propose to handle the height, given that it should be as realistic as possible to an application?

The satellite information can be withhold by restricting addNmeaListener.

[micolous]

I would propose that the altitude be handled similarly to the lat/long: that value is randomised with a range of ±(altitude accuracy), based on a fixed value given in the configuration. This would be fairly realistic to an application -- GPS is not very good at determining altitude.

I've double-checked the restrictions on addNmeaListener and I can see that it is ticked to restrict this function, and the app attempts to use this method. False co-ordinates are reported in GPS Status and Toolbox, however the satellite view remains fully functional.

The only allowed (unticked) options in Location are getProviders, isProviderEnabled and removeUpdates. All options in Phone are disabled (ticked), as are IPC and Sensors.

I'm getting the same (satellite) behaviour on 1.99.14 (248) and 1.99.25 (259), running CM 10.2.0 stable (4.3.1) on Nexus 7 2013 (deb), and Xposed 2.4.1 (app_process 47; XposedBridge 42).

[M66B]

I will look into the satellite info.

The average height of all land mass seems to be 686 meters. My proposal is to use this for the set height and use the accuracy to randomize it a bit.

[wbedard]

Any reason to hard code the value at all? If you can allow the user to specify the randomization range/value, why not allow them to specify the base. The default base value can be 686m. No matter what you choose it's going to be sub-optimal/inappropriate for some user(s).

[M66B]

I want to have as little as possible settings, that is why.

[wbedard]

While it's more a philosophical question at this point, might I ask why? I understand that coding in user-settable preferences takes extra time but that most "enthusiast" users enjoy the extra flexibility.

Is this simply one of the ways you limit your "up-front" investment in implementing a new feature or more an insistence on "clean" GUI appearance (including the settings screen)?

[M66B]

There are two reasons:

• UI components require more maintenance
• I like to keep XPrivacy simple to use

I am not only developing XPrivacy, but I will also maintain XPrivacy and I am trying to prevent to add an endless number of features, which will make maintenance more difficult.

The users in the XDA forum, like yourself, are not the average user. There are thousands of novice users who are easily overwhelmed with fearures that are not highly relevant to their privacy.