Re: [RFC PATCH 04/13] powerpc/dexcr: Support userspace ROP protection

2023-03-20 Thread Nicholas Piggin
On Tue Mar 7, 2023 at 3:37 PM AEST, Benjamin Gray wrote: > On Tue, 2023-03-07 at 15:05 +1000, Nicholas Piggin wrote: > > I think it is not quite per-process? I don't actually know how the > > user > > toolchain side is put together, but I'm thinking we can not give it a > > new > > salt on fork(),

Re: [RFC PATCH 04/13] powerpc/dexcr: Support userspace ROP protection

2023-03-06 Thread Benjamin Gray
On Tue, 2023-03-07 at 15:05 +1000, Nicholas Piggin wrote: > I think it is not quite per-process? I don't actually know how the > user > toolchain side is put together, but I'm thinking we can not give it a > new > salt on fork(), but we could on exec(). I think we could actually > give > each threa

Re: [RFC PATCH 04/13] powerpc/dexcr: Support userspace ROP protection

2023-03-06 Thread Nicholas Piggin
On Mon Nov 28, 2022 at 12:44 PM AEST, Benjamin Gray wrote: > The ISA 3.1B hashst and hashchk instructions use a per-cpu SPR HASHKEYR > to hold a key used in the hash calculation. This key should be different > for each process to make it harder for a malicious process to recreate > valid hash value

[RFC PATCH 04/13] powerpc/dexcr: Support userspace ROP protection

2022-11-27 Thread Benjamin Gray
The ISA 3.1B hashst and hashchk instructions use a per-cpu SPR HASHKEYR to hold a key used in the hash calculation. This key should be different for each process to make it harder for a malicious process to recreate valid hash values for a victim process. Add support for storing a per-thread hash