[llvm-branch-commits] [llvm] Add deactivation symbol operand to ConstantPtrAuth. (PR #133537)

[Oliver Hunt via llvm-branch-commits]

ojhunt wrote:

> > > I'm concerned about this - I initially thought this was for the purpose of the structure field protection in the frontend, but this is modifying the actual pointer auth intrinsics in the backend which is very concerning given the work we need to do to merging and protection etc.
> > 
> > 
> > Not sure I understand your concerns, can you be more specific?
> 
> I'm concerned about the interaction of these changes with ptrauth intrinsic optimizations, and the ability for attackers to gain control of the enablement flags.
> 
> But that said, this is a backend change so @ahmedbougacha should be the main reviewer.

I have checked in with @ahmedbougacha and his feeling is that this is fine as it requires a bunch of work to opt in, and for places where the security is important enough that we don't want people using this it's easy enough to block.

https://github.com/llvm/llvm-project/pull/133537