Comment by HackerNewt-doms
5 months ago
Is MTE on GrapheneOS restricted to some (newest?) Pixel models? Or does it work with all models that are currently supported by GrapheneOS itself?
5 months ago
Is MTE on GrapheneOS restricted to some (newest?) Pixel models? Or does it work with all models that are currently supported by GrapheneOS itself?
It's available since October 2023 when it launched on the Pixel 8. We integrated it into hardened_malloc that month and deployed it in production. We've been working on further research and improvements based on MTE since then.
GrapheneOS always uses it for the kernel, all of the base OS processes including apps with a couple exceptions, user installed apps opting into it and user installed apps solely written in Java/Kotlin which are very common on Android. For other user installed apps, there's a toggle for users to opt-in and most apps work with it already. For apps not known to work with it, there's a user-facing system for MTE crash reports and users can make an exception. Users can't disable it for base OS apps or apps which should work due to opting in or being pure Java/Kotlin.
Apple uses it for the kernel and parts of the base OS. They require opt-in by app developers and discourage doing it.
GrapheneOS is working on improvements to the kernel integration, Chromium PartitionAlloc integration and other aspects of it. We'll enable enforcement of tags for untagged memory once that's available, but we're also expanding the tagging. As an example, fully enabling stack allocation tagging has a more than acceptable performance cost for GrapheneOS but not Apple or Google. That's something we've been actively testing and will be deploying.
MTE is only available in hardware on Pixel 8 and later https://googleprojectzero.blogspot.com/2023/11/first-handset.... GrapheneOS supports all the Pixel 8 and 9 series phones. They plan to support Pixel 10 once Google stop delaying their open-source releases of AOSP.
MTE is also available on a bunch of non-Pixel devices we can't support or which don't meet our other requirements.
8th/9th generation Pixels are half of the devices we support. 7 years of support is the status quo but it was 3 years before the Pixel 6 raised it to 5 so the earlier devices aren't supported anymore.