[ARM ATTEND] catching up on exploit mitigations

From: Kees Cook
Date: Tue Jul 30 2013 - 15:05:45 EST

I'd like to propose the topic of catching up to x86 exploit
mitigations and security features, and potentially identifying
ARM-unique mitigations/features that could be implemented. Several
years ago, with Nicolas Pitre doing all the real work, I coordinated
getting ARM caught up on things like userspace ASLR and
stack-protector. Recently, based on work by Will Drewry, I ported
seccomp-bpf to ARM. I'd like to continue this kind of thing, and I
think it's overdue to examine this area again. A lot of work has
already been done by grsecurity in this area (see
http://forums.grsecurity.net/viewtopic.php?f=7&t=3292), so it would be
good to start there.

While it may expose my current ignorance of low level ARM mechanics,
I'd like to examine and discuss:

- RO and W^X kernel page table protections (similar to x86's
DEBUG_RODATA and DEBUG_SET_MODULE_RONX; it's not clear to me how much
LPAE and PXN is already handling this, if at all)

- something like x86's SMEP and SMAP (to deter kernel exploitation
from userspace)

- vector table protections (needs to be protected like the x86_64
vsyscall table, RO, etc)

- kernel ASLR (I'm close to having this upstreamable for x86)

- fuzzing (is anyone running trinity or similar on the ARM tree?)

- any other things ... ?



Kees Cook
Chrome OS Security
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