Messages in this thread | | | Date | Fri, 19 Oct 2018 16:54:10 +0100 | From | Mark Rutland <> | Subject | Re: [PATCH v5 07/17] arm64: add basic pointer authentication support |
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On Fri, Oct 19, 2018 at 08:36:45AM -0700, Kees Cook wrote: > On Fri, Oct 19, 2018 at 4:24 AM, Will Deacon <will.deacon@arm.com> wrote: > > Assuming we want this (Kees -- I was under the impression that everything in > > Android would end up with the same key otherwise?), then the question is > > do we want: > > > > - prctl() get/set operations for the key, or > > - prctl() set_random_key operation, or > > - both of the above? > > > > Part of the answer to that may lie in the requirements of CRIU, where I > > strongly suspect they need explicit get/set operations, although these > > could be gated on CONFIG_CHECKPOINT_RESTORE=y. > > Oh CRIU. Yikes. I'd like the get/set to be gated by the CONFIG, yes. > No reason to allow explicit access to the key (and selected algo) if > we don't have to.
As a minor aside, the PAC algorithm (which can be IMPLEMENTATION DEFINED) is fixed in HW, and cannot be selected dynamically.
Thus if a process is using pointer authentication, it would not be possible for CRIU to migrate that process to a CPU with a different PAC algorithm.
Thanks, Mark.
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