Subject: Re: [PATCH v5 next 1/5] modules:capabilities: add request_module_cap()

From: "Serge E. Hallyn" <[email-masked]>
Date: Wed, 29 Nov 2017 11:28:52 -0600

Quoting Theodore Ts'o ([email-masked]):
> Half the problem here is that with containers, people are changing the
> security model, because they want to let untrusted users have "root",
> without really having "root".  Part of the fundamental problem is that
> there are some well-meaning, but fundamentally misguided people, who
> have been asserting: "Containers are just as secure as VM's".
> 
> Well, they are not.  And the sooner people get past this, the better
> off they'll be....

Just to be clear, module loading requires - and must always continue to
require - CAP_SYS_MODULE against the initial user namespace.  Containers
in user namespaces do not have that.

I don't believe anyone has ever claimed that containers which are not in
a user namespace are in any way secure.

(And as for the other claim, I'd prefer to stick to "VMs are in most
cases as insecure as properly configured containers" :)

-serge