Comment 5 for bug 1516249

> Other apps, such as the "Document Viewer" seem to be perfectly able to
> see the local filesystem...

Document Viewer is only allowed to see files under $HOME/Documents.

> Same for the terminal app, and any programs started by it

Yes, the terminal app is a special case, and as you’ve probably noticed, it asks your su password at startup, which should make it really clear that it has special privileges and is not to be left in everyone’s hands.

> Why not *make* it an exception?

Because that would allow anyone who gets physical access to your phone to read any file on the FS, including sensitive information, thus largely invalidating the security model.

> putting passwords in a file:/// would be one way to work around bug #1516220

Another much safer way would be an app that stores those passwords with strong encryption and a master password. That would make for a nice addition to the ubuntu app store.