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Wonderfall 2022-01-03 00:18:06 +01:00
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content/posts/fdroid-issues.md
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@ -18,7 +18,7 @@ To understand why this is a problem, you'll have to understand a bit about F-Dro
Unlike other repositories, F-Droid signs all the apps (at least in its main repository, we'll get back to it later) with app keys it always owns. A signature is a mathematical scheme that guarantees the authenticity of the applications you download. Upon the installation of an app, Android pins the signature across the entire OS (including user profiles): that's what we call a trust-on-first-use model since all subsequent updates of the app must have the corresponding signature to be installed. Unlike other repositories, F-Droid signs all the apps (at least in its main repository, we'll get back to it later) with app keys it always owns. A signature is a mathematical scheme that guarantees the authenticity of the applications you download. Upon the installation of an app, Android pins the signature across the entire OS (including user profiles): that's what we call a trust-on-first-use model since all subsequent updates of the app must have the corresponding signature to be installed.
Normally, the developer is supposed to sign their own app prior to its upload on a distribution channel, whether that is a website or a traditional repository (or both). You don't have to trust the source (usually recommended by the developer) except for the first installation: future updates will have their authenticity cryptographically guaranteed. The issue with F-Droid is that all apps are signed by the same party (F-Droid) which is also not the developer. You're now adding another party you'll have to trust, which isn't ideal: the fewer parties, the better. Normally, the developer is supposed to sign their own app prior to its upload on a distribution channel, whether that is a website or a traditional repository (or both). You don't have to trust the source (usually recommended by the developer) except for the first installation: future updates will have their authenticity cryptographically guaranteed. The issue with F-Droid is that all apps are signed by the same party (F-Droid) which is also not the developer. You're now adding another party you'll have to trust, which isn't ideal: **the fewer parties, the better**.
F-Droid also requires that the source code of the app is exempt from any proprietary library or ad service, according to their [inclusion policy](https://f-droid.org/en/docs/Inclusion_Policy/). Usually, that means that some developers will have to maintain a slightly different version of their codebase that should comply with F-Droid's requirements. F-Droid also requires that the source code of the app is exempt from any proprietary library or ad service, according to their [inclusion policy](https://f-droid.org/en/docs/Inclusion_Policy/). Usually, that means that some developers will have to maintain a slightly different version of their codebase that should comply with F-Droid's requirements.
@ -47,11 +47,11 @@ allow untrusted_app_25 proc_misc:file r_file_perms;
allow untrusted_app_25 proc_tty_drivers:file r_file_perms; allow untrusted_app_25 proc_tty_drivers:file r_file_perms;
``` ```
This is a mere sample of the SELinux exceptions that have to be made on older API levels so that you can understand why it matters. This is a mere sample of the [SELinux exceptions](https://android.googlesource.com/platform/system/sepolicy/+/refs/tags/android-12.0.0_r21/private) that have to be made on older API levels so that you can understand why it matters.
It turns out the official F-Droid client doesn't care much about this since it lags behind quite a bit, targeting the API level 25 (of which some SELinux exceptions were shown above). As a workaround, some users recommended third-party clients such as Foxy Droid or Aurora Droid. While these clients might be technically better, they're poorly maintained for some, and they also introduce yet another party to the mix. It turns out the official F-Droid client doesn't care much about this since it lags behind quite a bit, **targeting the API level 25** (of which some SELinux exceptions were shown above). As a workaround, some users recommended third-party clients such as [Foxy Droid](https://f-droid.org/en/packages/nya.kitsunyan.foxydroid/) or [Aurora Droid](https://f-droid.org/en/packages/com.aurora.adroid/). While these clients might be technically better, they're poorly maintained for some, and they also introduce yet another party to the mix.
F-Droid also doesn't enforce a minimum target SDK for the official repository. Play Store does that quite aggressively for new app updates, and while it may seem bothersome, it's a necessity to keep the app ecosystem modern and thus healthy. F-Droid's approach sends the wrong message to developers (and even users) because they should care about it, and this is why many of us think it may be even harmful to the FOSS ecosystem. Backward compatibility is often the enemy of security, and while there's a middle-ground for convenience and obsolescence, it shouldn't be exaggerated. F-Droid also **doesn't enforce a minimum target SDK** for the official repository. Play Store [does that quite aggressively](https://developer.android.com/google/play/requirements/target-sdk) for new app updates, and while it may seem bothersome, it's a necessity to keep the app ecosystem modern and thus healthy. F-Droid's approach sends the wrong message to developers (and even users) because they should care about it, and this is why many of us think it may be even harmful to the FOSS ecosystem. Backward compatibility is often the enemy of security, and while there's a middle-ground for convenience and obsolescence, it shouldn't be exaggerated.
## 4. General lack of good practices ## 4. General lack of good practices
The F-Droid client allows multiple repositories to coexist within the same app. Many of the issues highlighted above were focused on the main official repository which most of the F-Droid users will use anyway. However, having **other repositories in a single app also violates the security model of Android** which was not designed for this at all. As a matter of fact, the new unattended update API from Android 12 that allows seamless updates for third-party clients without privileged access to the system won't work with F-Droid. The F-Droid client allows multiple repositories to coexist within the same app. Many of the issues highlighted above were focused on the main official repository which most of the F-Droid users will use anyway. However, having **other repositories in a single app also violates the security model of Android** which was not designed for this at all. As a matter of fact, the new unattended update API from Android 12 that allows seamless updates for third-party clients without privileged access to the system won't work with F-Droid.