User namespaces and keys

Casey Schaufler casey at
Wed Feb 23 13:37:16 PST 2011

On 2/23/2011 12:55 PM, Eric W. Biederman wrote:
> Casey Schaufler <casey at> writes:
>> I confess that I remain less well educated on namespaces than
>> I probably should be, but with what I do know it seems that the
>> relationships between user namespaces and LSMs are bound to be
>> strained from the beginning. Some LSMs (SELinux and Smack) are
>> providing similar sandbox capabilities to what you get from user
>> namespaces, but from different directions and with different
>> use cases.
> Casey I won't argue about the possibility of things being strained, but
> I think if we focus on the semantics and not on the end goal of exactly
> how the pieces are to be used there can be some reasonable dialog.

I'm sure that there will be cases where they will work together
like horses in a troika. Making sensible semantics for the interactions
is key, and it is entirely possible that in some cases a comparison
of semantics and behaviors will lead an end user to chose either an
LSM or namespaces over the combination. Just like I expect that even
when we allow multiple LSMs the SELinux and Smack combination will be
rare among the sane.

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