Android Content provide leading to SecurityException: Permission Denial if not used immediately

Issue

In my Android Manifest I registered my Activity for being able to "open" specific files. This all works fine. When I receive the new Intent and read the file data from the intent via

BufferedReader(InputStreamReader(contentResolver.openInputStream(intent.data)))

it works fine. However, for a better view flow, I wanted to store the URI of the intent and show it in another view (asking the user how to proceed with the file). So I store this intent.data as a String and open another view first.

However, once the view is opened, I bascially call the same thing

val br = BufferedReader(InputStreamReader(act.contentResolver.openInputStream(fileUri)))

but here I get an exception

java.lang.SecurityException: Permission Denial: reading [FileBrowserApp I used for "opening the file"] uri content://... from pid=5242, uid=10159 requires the provider be exported, or grantUriPermission()

So it feels like the URI is somehow expired or such thing? Is this actually the case? Do I have to read the file directly when I receive the Intent? I was hoping for a way to keep the URI until I want to read the file.

Solution

I found the issue. Turns out, it is not a problem of an expiring Intent or anything like that. Instead my own "processing" changed the path.

What I did was taking the incoming Intent data as Uri. Later I fetched the provider path from that Uri again. However this caused a transformation of the query (instead of leaving it as a String in the first place) breaking the path.

In short: the problem is the URL encoding/decoding.

The original intent path (opened via the TotalComander - hence the com.ghisler path) looked like this:

content://com.ghisler.files/tree/primary%3A/document/primary%3Astorage%2Femulated%2F0%2Fbackup.bak

However getting the path from the Uri the colons were decoded leaving an output path of this:

content://com.ghisler.files/tree/primary:/document/primary:storage/emulated/0/backup.bak

You can clearly see the different encoding. As a consequence the file path was simply not the same after fetching it from the Uri again. This was causing the Exception - not an invalidation of the intent.

Answered By - Tobias Reich