On 2022-08-09 12:52:28-0400, Dave Levine wrote:
> I currently use OpenBSD on my laptop for a number of reasons, mainly
> performance and hardware support. However, I have been considering
> setting up a multiuser POWER9 box for some Discord friends and I to
> work on in a hobbyist setting (these things are expensive and I'm the
> one who currently has the machine we want to work on), but need to
> know if OpenBSD is a good option for that. As it apparently lacks
> mitigations for multiple medium-risk hardware side channel attacks, I
> think it is important to ask: What does OpenBSD do to stop an
> unprivileged user with access to a compiler or shell from copy-pasting
> a proof-of-concept exploit to siphon e.g. SSH private keys, root
> passwords and the like, or are these more difficult to exploit than I
> give them credit for with things like (K)ASLR enabled?
I know at least for Intel and AMD there are mitigations against
Spectre/Meltdown-type exploits by disabling speculative execution by
default, but I don't know about POWER9 (or if that is even an issue
there). You might have to do some mail list and other searching to see.
But in general, OpenBSD seems to be the least-likely OS to allow
privilege escalation (see www.openbsd.org under the security link, LH
side near top, only 2 remotely exploitable holes in the default install
since ~1996, etc).
Due to recent reports of a bug allowing key detection based on cpu usage
variations ("turbo boost" etc), I have my system set to keep a steady
cpu frequency.
I'm not an expert; that may or may not help. Best of luck to you.
