Subject: Re: [PATCH] x86: Lock down MSR writing in secure boot
Date: Wednesday 13th February 2013 05:39:22 UTC (over 4 years ago)
On Tue, 2013-02-12 at 16:48 -0800, H. Peter Anvin wrote: > OK... what none of this gets into: > > Why should CAP_RAWIO be allowed on a secure boot system, when there are > 2^n known ways of compromise a system with CAP_RAWIO? CAP_SYS_RAWIO seems to have ended up being a catchall of "Maybe someone who isn't entirely root should be able to do this", and not everything it covers is equivalent to being able to compromise the running kernel. I wouldn't argue with the idea that maybe we should just reappraise most of the current uses of CAP_SYS_RAWIO, but removing capability checks from places that currently have them seems like an invitation for userspace breakage.