Re: [PATCH V3 08/11] kexec: Disable at runtime if the kernelenforces module loading restrictions

From: Matthew Garrett
Date: Sun Sep 08 2013 - 13:38:23 EST


On Sun, 2013-09-08 at 10:32 -0700, James Bottomley wrote:
> On Sun, 2013-09-08 at 17:27 +0000, Matthew Garrett wrote:
> > > It's an argument that CAP_SYS_BOOT is too powerful yes, but if you
> > > recall, I said I keep that one. In the rather lame analogy, what I do
> > > by giving away CAP_SYS_MODULE and enforcing module signing while keeping
> > > CAP_SYS_BOOT is allow people into my conservatory to play with the
> > > plants but not into my house to steal the silver ... saying CAP_SYS_BOOT
> > > is too powerful doesn't affect that use case because I haven't given
> > > away CAP_SYS_BOOT.
> >
> > Ok, sorry, I had your meaning inverted. Yes, permitting the loading of
> > signed modules while preventing the use of kexec is a completely
> > reasonable configuration - so reasonable that it's what this patch
> > causes the kernel to do automatically.
>
> Well, no, it doesn't because with this patch, *I* can't use kexec ...
> you've just locked me out of my own house.

Hm. Ok, that's a more compelling argument than Greg's. Let me think
about whether there's a convenient way of supporting this.

--
Matthew Garrett <matthew.garrett@xxxxxxxxxx>
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