[jbg_]

Just to provide some context for the "very important security feature" that is disabled. The change adds a permission that allows (after explicit whitelisting by the user) an app to impersonate another app.

Specifically, it allows microG apps (which are open-source and auditable) to impersonate Google Play Services apps (which are closed-source and not auditable) and thus provide their functionality.

[Aissen]

Why not hardcode this for microG only, and not any system app ?

[SifJar]

I think it's not really in the spirit of openness/freedom to say "you can replace Google's software, but ONLY with ours"

[gjjrfcbugxbhf]

You could allow this in config though. I.e.

() No app spoofing () Microg apps can spoof Google apps () Any apps can spoof any apps

[mtgx]

They could still make it default and then allow an option in settings to allow other apps.

This would be similar to how root apps originally allowed anything to use root capabilities (with user permission), and then they made the default "Apps-only".

[jbg_]

Well, functionally that would be the same as if you just don't grant the permission to any other app than microG. Unless you don't trust that Android's permissions work properly, but then I think you have much bigger problems.

[kuschku]

If you can put an app into /system/priv-app, you can already overwrite everything.

The only thing this patch does is provide a clean API for it, so that microG doesn't have to patch your entire system every time.

[seba_dos1]

You can't install any system apps without root permissions, and at this point you can do anything, so why bother?

[kasey_junk]

Minor nitpick. Closed source software is of course audit-able. Being able to audit binaries is table stakes to even call someone an auditor.

There may be many valid reasons to prefer open source software but security audits aren’t one of them.

[Sir_Cmpwn]

I'm gonna take it on good faith that you're not a troll...

Open source software is much easier to audit than closed source software. People have a finite amount of time to do things like audit their software.

[fabrice_d]

But auditing the source is only useful if you can do reproducible builds to be sure you run the audited source.

This is rarely the case unfortunately, and for most of open source prebuilt software you use, you rely on trust and not on audit.

[Sir_Cmpwn]

That's not true. You could always, you know, run the version you compiled yourself.

[kasey_junk]

We’ve known for 30 years that’s not enough (depending on your risk characteristics).

Trusting trust is one of the seminal talks in software.

[Sir_Cmpwn]

We've known that in theory your compiler et al can be backdoored but in practice we can feel a lot safer compiling our own software than using proprietary binaries.

[gjjrfcbugxbhf]

There are different types of audits. Yes someone doing a full security audit is going to be happy with doing reverse engineering. But I can perform a quick check on a lot of the software that I use that it doesn't do user hostile things (like ring home on startup) this is harder to do on a binary - so given the choice I'll use the open source option.

[kasey_junk]

For those kind of checks why would you look at the source? Stick a proxy between the internet and the device to see what it does.

Seems waaaay easier than looking for the mythical badCodeGoesHere function.

[gjjrfcbugxbhf]

Because I can trivially read and run code in my head I do that all day. I don't have a clue how to set up a proxy. Also my scan over the code tells me if it is generally badly writtes and a lot more than just one example of potential bad behaviour.

[kasey_junk]

You are more prepared to run arbitrary code “in your head” than setup a simple network proxy?... uh huh

[gjjrfcbugxbhf]

Yeah. As a developer the former is literally the $dayjob. The latter - I've never done so it could be simple or it could be hard. I've heard that getting software to respect proxies is tricky though...