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Disabling Location permission on Android 6 seems to affect WiFi parameter queries

I have an Android application that accesses the device's location and then queries the WiFi parameters. Everything typically runs smoothly.

If I turn off the Location permission for the app (as I can do in Android 6) I no longer get the device's location (as is expected). However, I also get a modified WiFiInfo object when I try to query the WiFi parameters. In particular:

  • getScanResults() normally lists all of the networks available, but with Location turned off it only contains the network the device is connected to.
  • If I look at the capabilities of the network that is found, the string is empty. Normally it contains information such as the wireless encryption information.

Has anyone else seen this? I've verified it using the same code with the Location permission turned on/off on 2 different devices. Any idea on what's happening?

Update: On further review, I was wrong when I said that getScanResults() returns information about the AP that the device us connected to. It in fact returns an empty list. This would support the idea that Google doesn't want us to have any information about the local APs if Location permission is denied.

Solution

  • WiFi-based location is basically a lookup of WiFi access point information in a giant database of known APs and locations to discover where a device is. This is what services such as Google, SkyHook, and Apple use when you enable WiFi or network location.

    I suspect Google is trying to prevent an application from accessing information from which location can be derived when location is disabled. They have previously blocked access to Google Play location services when location is disabled, but this does not prevent a device from doing a scan, collecting the same data that would be sent to Google, and sending this data to a different service to discover location.