Daniel Micay on Twitter: "@kees_cook @johnstultz_work It's also unfortunate that it requires an extra system call. Bionic removed a bunch of the labels due to the cost added to thread spawning. They're almost always set on the whole memory region after an mmap or mprotect call. Requiring extra system calls deters using the feature." / Twitter

Sweet! Daniel Rosenberg's encryption with casefolding on ext4 feature has landed upstream! This has been an out of tree dependency needed for booting AOSP, so its great its been merged! git.kernel.org/pub/scm/linux/

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John Stultz

@johnstultz_work

May 3, 2021

I think all that's left needed for generic AOSP functionality right now is the PR_SET_VMA_ANON_NAME feature. android.googlesource.com/kernel/common/

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It's also unfortunate that it requires an extra system call. Bionic removed a bunch of the labels due to the cost added to thread spawning. They're almost always set on the whole memory region after an mmap or mprotect call. Requiring extra system calls deters using the feature.

12:38 AM · May 4, 2021Twitter Web App

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hardened_malloc only uses it in debug builds (AOSP userdebug and eng build variants, not user) because of the added overhead. It's a genuinely useful feature though. An example of the output with hardened_malloc: gist.github.com/thestinger/28c Can speed up figuring out UAF bugs, etc.

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gist:28cd1df0226bd63ead4ea7ec9ed6176d

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It would help a bit to be able to set more than one at a time but it would still be worse than being able to set them with mmap / mprotect. So, for example, hardened_malloc uses mappings directly for sizes above either 128k (default) or 16k (extended size classes disabled).

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