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Just to provide some context for the "very important security feature" that is disabled. The change adds a permission that allows (after explicit whitelisting b
by jbg_ 9y ago
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.
- kasey_junk 9y agoMinor 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 9y agoI'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 9y agoBut 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 9y agoThat's not true. You could always, you know, run the version you compiled yourself.
- kasey_junk 9y agoWe’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 9y agoWe'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.
- kasey_junk 9y agoI think that might be where we disagree. Without a competent security audit I think you are falling back to trust. Open Source vs Closed source is not where I or the security professionals I know put most trust emphasis. I would enthusiastically trust something closed from Google over a rando open source project. But back to the original point, even the most basic audit steps are the same on an open source project vs closed one. Observe what the binary does & inspect it for standard patterns.
- Sir_Cmpwn 9y agoObservation only goes so far. You couldn't find backdoors unless you started to decompile it. I think having a trusted compiler is an important first step to trusting software, even if you have to analyize it in depth yourself.
- kasey_junk 9y ago2 actually: https://www.dwheeler.com/trusting-trust/dissertation/wheeler-trusting-trust-ddc.pdf https://www.dwheeler.com/trusting-trust/dissertation/wheeler... But note you are now adding a lot of extra preconditions that are largely not available. The counter argument is reverse engineering & black box audits are actually easier than getting the conditions right to trust code audits. As a bonus they work regardless of the code availability.
- gjjrfcbugxbhf 9y agoThere 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 9y agoFor 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 9y agoBecause 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 9y agoYou are more prepared to run arbitrary code “in your head” than setup a simple network proxy?... uh huh
- gjjrfcbugxbhf 9y agoYeah. 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...
- kasey_junk 9y agoSo um. I'm a developer and the idea that I could take an arbitrary code base and get it into my headspace in less time than it would take me to figure out a programs network interactions is one of the most absurd things I've ever heard.
- Aissen 9y agoWhy not hardcode this for microG only, and not any system app ?
- jbg_ 9y agoWell, 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.
- SifJar 9y agoI think it's not really in the spirit of openness/freedom to say "you can replace Google's software, but ONLY with ours"
- gjjrfcbugxbhf 9y agoYou could allow this in config though. I.e. () No app spoofing () Microg apps can spoof Google apps () Any apps can spoof any apps
- mtgx 9y agoThey 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".
- seba_dos1 9y agoYou can't install any system apps without root permissions, and at this point you can do anything, so why bother?
- kuschku 9y agoIf 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.