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

From: James Bottomley
Date: Sun Sep 08 2013 - 13:33:24 EST


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.

James


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