App bypassing storage scopes?

avrutg

There is this app, called Zarchiver. I configured it with storage scopes and maybe I don't understand something, but it can clearly read files that were not created by it. I thought that when I use storage scopes, there is no way for an app to bypass do and then I get this. What is going on here?

spiral

avrutg I ran into this with Zarchiver and was confused about it too. It seems that with storage scopes on, zarchiver can read any file/folder that it unzips. So, to get around that, I unzip the file/folder to a temporary location (after which zarchiver will be able to see), then I move the file/folder to whatever permanent storage location I want it to be in. Assuming that permanent location is not configured as viewable in storage scopes, zarchiver won't be able to see the file/folder after the move to that new location. This is what has worked for me.

avrutg

Maybe it has to do with the fact that these are system files and can be read by any app?

TrustExecutor

I also had this issue with Onedrive and Outlook. I ended up using a separate profile for those apps. I set storage scopes for a created directory but I could still see and attach a file from any other directory from within theapp. Is it because those apps use Android storage access framework in a different way than other apps?

muhomorr

TrustExecutor

TrustExecutor s. I set storage scopes for a created directory but I could still see and attach a file from any other directory from within theapp

The important thing to understand is that the standard file picker is a separate system app that has full access to shared storage. Any app can launch this picker, because it grants access to files/folders only after explicit consent by the user.

MetropleX

Having set Storage Scopes have you removed the standard storage permissions?

Shouldn't have both.

avrutg

spiral Shouldn't this be considered a bug then?

spiral

avrutg I'll let someone else make that call. Perhaps, I'm doing something incorrectly. Let's see if one of the devs chimes in.

spiral

avrutg actually I don't think this is a bug. Zatchiver sees the file that it unziped as a file it created. Storage Scopes says that the app will see any file it creates. I think zarchive's behavior is in line with Storage Scopes.

avrutg

spiral The thing is not unzipping. See my latest comment. Zarchiver sees files that were not created by any user-installed app, let alone zarchiver

[deleted]

It's not a bug. If you have Storage Scopes enabled, an app can see files it creates but not others. It's a way of making the app think it has broad access to storage when it's actually confined to its own scope.

Please read https://grapheneos.org/usage#storage-access

avrutg

[deleted] I literally said that it sees files it did not create. Did you read what I wrote? For example /system_ext/app/blahblahblah. This is on Pixel 4a. These are system files and clearly were not created by Zarchiver.

muhomorr

avrutg Storage access permissions and Storage Scopes control access to the shared storage, not to system files.

Read-only access to system files doesn't require any permission. Content of system partitions is public information, it's the same on all devices that run a given GrapheneOS version. These files aren't encrypted for the same reason. This is not something that is changed by GrapheneOS, stock Android behaves the same way.

avrutg

muhomorr Thank you for the answer! That was my initial thought and you confirmed it

TrustExecutor

muhomorr Thanks for the clarification.