With Google's Android, this issue will never arise because Android is open source. Any attempt to plant a backdoor will be outright monitored by the community.
This isn't true. You can stick to app repositories like F-Droid and use Raccoon to download Play Store apps via your desktop without using a Google account on your phone.
I don't use them personally but I imagine Goole Now, GMail and Google Maps would need Play Services.
The apps I do use (non-google) tend to function well enough without Play Services though.
Anyone who does is a rounding error.
> Anyone who does is a rounding error.
I'm actually curious if there is literally anyone who uses no proprietary software, including the radios and the SoC, on their Android device.
My bet is that there's not even a single device out there for which this is possible. (If there is, I'd love to see it.)
According to them, there are unfortunately no baseband modems on the market that can legally have their firmware distributed as free software. Their workaround is to keep the modem as isolated from the CPU/RAM as possible.
What is the legal restriction here? (It sounds like you're referring to some restriction beyond simple copyright protection on some of their components - are there FCC regulations regarding the firmware?)
EDIT: Ah, of course, the FCC needs to certify devices before they can actually be used.
>We unfortunately cannot provide free baseband modem firmware, as there is no option available on the market which would be able to fulfil this requirement. Even if it existed, it would bring very little value to the users, as operating a radio device with modified firmware on public networks without recertification is prohibited in most jurisdictions of the world and privacy concerns in cellular networks are mostly related to what happens on the network side, not inside the device.
I don't have any more information than this. If someone can quote specific FCC regulations to back this up, I would find that very interesting :)
Not entirely true, publishing the code isn't the same as allowing its modification. Code signing can be used to limit which versions are allowed to run.
Reproducible builds of the source would allow one to ensure that the binary, certified version of the code their baseband processor is running is legit (i.e. not backdoored). It would also help audit the code and spot security holes.
If I can't run my home-compiled versions of your code - whether because of code signing restrictions or because of federal law prohibiting firmware that hasn't been certified - it's not free[0]. So without without reproducible builds, providing the source code for the firmware provides very little benefit (since I have no way to prove that the code corresponds to what's actually running on the device, nor any legal way to install and run it on the device myself.)
Reproducible builds could in theory work, but actually getting builds to be bit-for-bit reproducible is not an easy feat. I'd be very surprised if firmware were capable of this.
[0] This is a great example of why a free software license doesn't necessarily mean that the software is free. It means that the author has waived his/her ability to restrict your freedom to use/modify/distribute the software, but that doesn't mean that third parties (ie, the government, or a patent troll) have done the same.
Basebands aside, the rest of the device is somewhat feasible to see being open.
Despite the openness of Android/AOSP, there are still, unfortunately, things like binary blobs for certain graphics chips and closed-source firmware for things like Wi-Fi chipsets. Given what we've seen agencies like NSA are capable of (intercepting hardware in transit to apply backdoors, paying off RSA to make Dual EC the default pRNG in their crypto libraries, etc.), them compelling a manufacturer of a component to include a backdoor in their closed-source blobs is no stretch of the imagination.
Apple even has this problem: basebands in cellular modems are notorious for being the source of exploits in otherwise-secure phones.