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this has nothing to do with androids permission system at all... epic made the decision to distribute Fortnite themselves while bypassing the Play Store in orde

this has nothing to do with androids permission system at all... epic made the decision to distribute Fortnite themselves while bypassing the Play Store in order to save on the 30% cut google would otherwise get from game sales. This worked by installing an app manually that did download the game and installs or updates it afterwards. This installer had a serious flaw allowing malicious apps to install other software by abusing rights the installer had gained to install or update the game. You could claim google has been irresponsible for publishing technical details about this flaw in epics installer too early but it still has nothing to do with Androids permission system.

scarface74 7y ago
From the article “However, on Aug. 15, a Google researcher discovered a flaw with the installer, which can let a separate app on your phone hijack what the software actually downloads.” So a separate app can hijack what another app does. That means the sandbox is broken.
- mercora 7y ago
  their installer downloaded the game into shared storage. They should at least have known that access to shared storage is not sandboxed and should have been verifying what they are about to install instead of trusting no other app would maliciously place an apk where their installer did expect it to be... ideally they would never have used shared storage at all... that said, the sandboxing and permission system worked as expected.
  - scarface74 7y ago
    So you have to trust the app not to do anything stupid or malicious? Isn’t the whole point of an operating systems permission system so you don’t have to trust the developer? All apps having access to shared storage without explicit permission is no better than computer operating systems. If an app can trash your user data the permission system is useless.
    - mercora 7y ago
      If you install an app that has permission to install other apps with arbitrary permission sets... Yes, you must trust them not to do anything stupid or malicious. However this is by choice you don't have to trust them although that means you should not allow them either. I would agree that conflating external storage options with shared storage was a huge mistake which made developers somewhat unaware that this is something that is actually not sandboxed as anything else would have been. But i think nonetheless it is the responsibility of the developer to not just assume how stuff works and in this case it is quite obvious if you actually happen to ask yourself if something like this would be possible. This is especially true if you require novice users to install your app with delicate permissions as the ability to install other apps. To be clear on this, they made the choice to use shared storage instead of using storage protected by androids sandboxing and permission systems. They probably made this choice without knowing that they are effectively allowing other apps access to files of their installer because shared storage has been conflated with external storage options but mainly because they did not evaluate the options they had and the implications of those carefully enough. Apparently Android 10 improved this somehow (probably by making filesystem permissions work as usual).
- berdario 7y ago
  No. There are things intentionally included and things intentionally excluded from the sandbox. App-specific data storage is part of the former, and external storage access is part of the latter (this changed with Android 10, anyhow). Epic's installer used the external storage

scarface74 7y ago

From the article “However, on Aug. 15, a Google researcher discovered a flaw with the installer, which can let a separate app on your phone hijack what the software actually downloads.” So a separate app can hijack what another app does. That means the sandbox is broken.

mercora 7y ago
their installer downloaded the game into shared storage. They should at least have known that access to shared storage is not sandboxed and should have been verifying what they are about to install instead of trusting no other app would maliciously place an apk where their installer did expect it to be... ideally they would never have used shared storage at all... that said, the sandboxing and permission system worked as expected.
- scarface74 7y ago
  So you have to trust the app not to do anything stupid or malicious? Isn’t the whole point of an operating systems permission system so you don’t have to trust the developer? All apps having access to shared storage without explicit permission is no better than computer operating systems. If an app can trash your user data the permission system is useless.
  - mercora 7y ago
    If you install an app that has permission to install other apps with arbitrary permission sets... Yes, you must trust them not to do anything stupid or malicious. However this is by choice you don't have to trust them although that means you should not allow them either. I would agree that conflating external storage options with shared storage was a huge mistake which made developers somewhat unaware that this is something that is actually not sandboxed as anything else would have been. But i think nonetheless it is the responsibility of the developer to not just assume how stuff works and in this case it is quite obvious if you actually happen to ask yourself if something like this would be possible. This is especially true if you require novice users to install your app with delicate permissions as the ability to install other apps. To be clear on this, they made the choice to use shared storage instead of using storage protected by androids sandboxing and permission systems. They probably made this choice without knowing that they are effectively allowing other apps access to files of their installer because shared storage has been conflated with external storage options but mainly because they did not evaluate the options they had and the implications of those carefully enough. Apparently Android 10 improved this somehow (probably by making filesystem permissions work as usual).
berdario 7y ago
No. There are things intentionally included and things intentionally excluded from the sandbox. App-specific data storage is part of the former, and external storage access is part of the latter (this changed with Android 10, anyhow). Epic's installer used the external storage