An important security feature not being fully implemented due to it being a development annoyance is problematic. GrapheneOS is an aftermarket OS focused on Pixels and we wanted this feature to start being used properly and complained about it not being done on the past devices.
Conversation
Not everyone using an aftermarket OS wants to roll back the security model and disable security features. Proper verified boot is a small part of what we expect potential hardware partners to implement. It's not proper verified boot if firmware bypasses aren't fixed like this.
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You're welcome to use something other than GrapheneOS if you don't want the standard security model and hardware-based security features intact. Rollback protection is a basic security feature and has already been used for years, just not for the early SoC boot chain in practice.
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And ultimately, that's why I don't use GrapheneOS.
But it could be a great OS if it didn't insist on denying owners control of their devices, so it's a shame.
It's looking like this case wasn't even a security fix, just DRM.
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Verified boot is an important security feature primarily used to make privileged persistence much more difficult for an attacker. If they can simply write out a vulnerable SoC boot chain, it doesn't work. It's secondarily used for anti-tampering and the same thing applies to it.
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Yes, but my security model (for my phone) assumes I always have physical custody of my phone, so verified boot is worthless to me.
I understand and agree it is important to others.
I'm not suggesting taking any of that away from them.
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The primary threat model for verified boot is defending against a remote attacker trying to persist on the device, not physical security. Anti-tampering is a secondary and less important threat model for verified boot. Chromebooks don't really bother even trying to do that part.
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Verified boot on ChromeOS is entirely for defending against remote attackers. Verified boot on Android is primarily for that but also tries to make tampering much harder, although it's a different kind of thing than the remote threat model it defends against.
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The primary threat model is an attacker uses an exploit chain to get temporary control over the OS. They use a Linux kernel exploit and own the kernel, etc. Due to verified boot, their persistence is gone after a factory reset unless they have working verified boot exploits too.
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Even without a factory reset, verified boot helps to contain them and make them lose their access. This is the focus of the Auditor app on GrapheneOS: detecting signs of a compromise using hardware features built on verified boot and the hardware keystore attestation features.