Re: [PATCH v5 07/17] arm64: add basic pointer authentication support

From: Cyrill Gorcunov
Date: Fri Oct 19 2018 - 12:49:34 EST

On Fri, Oct 19, 2018 at 12:24:04PM +0100, Will Deacon wrote:
> FWIW: I think we should be entertaining a prctl() interface to use a new
> key on a per-thread basis. Obviously, this would need to be used with care
> (e.g. you'd fork(); use the prctl() and then you'd better not return from
> the calling function!).
> 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.

Indeed. Without get/set I think we won't be able to restore programs.