| From | Sami Tolvanen <> | Date | Mon, 2 May 2022 08:31:35 -0700 | Subject | Re: [RFC PATCH 00/21] KCFI support |
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On Sat, Apr 30, 2022 at 9:08 AM Kenton Groombridge <me@concord.sh> wrote: > Many thanks for continuing to work on this! As a user who has been > following the evolution of this patch series for a while now, I have a > couple of burning questions: > > 1) The LLVM patch says that kCFI is not compatible with execute-only > memory. Is there a plan ahead for kCFI if and when execute-only memory > is implemented?
There's no plan for executable-only memory right now, that would require type hashes to be moved somewhere else to read-only memory.
> 2) kCFI only checks indirect calls while Clang's traditional CFI has > more schemes like bad cast checking and so on. Are there any major > security tradeoffs as a result of this?
No, cfi-icall is only scheme that's relevant for the kernel. The other schemes implemented in Clang are mostly useful for C++.
Sami
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