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Presumably there's something special about ro.boot.vbmeta.digest that would prevent a malicious ROM from lying about it? As in the ADB protocol being served by literal ROM code?

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Yeah this seems to be a fairly important missing piece. Is there some special boot mode with a ROM-hosted unmodifiable adb?

That value comes from the firmware and is not writable by Android. As for whether the daisy-chain of strcpy() calls are robust, and without a rich history of 0-days, that is something I don't know.

> That value comes from the firmware and is not writable by Android.

But it's returned to the host by adbd that's part of Android. What's stopping someone from creating a modified adbd that would lie about this value?

I don't know that much about the security model. But I think if you really want to verify device integrity you should use an attestation key. That is supposed to be un-spoofable (although bugs can still occur in any software, which would defeat the integrity guarantees).

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