Re: severe security issue on dom0/xend/xm/non-root users

[Tommi Virtanen <tv@tv.debian.net>]

Kurt Garloff wrote:
>>There's a simple reason why that's not really what you want.
>>
>>Imagine two security-sensitive services, with different sets of
>>allowed users. Using UNIX domain sockets with filesystem access
>>control allows using two groups to list the allowed users for each
>>service -- using <1024 source port does not.
> 
> It does.
> The frontend (that would acquire the privileged socket) would need
> to be setuid root for this and then could enforce whatever policies,
> much more flexible than the Unix group membership model if you want.

Oh, the group-restricted UNIX domain socket wins there, too.

Your model:

   - setuid client that only lets certain users open ports <1024

My model:

   - setgid client that only lets certain users connect to the protected
     socket
OR
   - just add the certain users to the group, and let them access the
     protected socket.

The UNIX domain socket way is both more flexible and _more secure_
-- it only needs setgid where the port<1024 thing needs setuid.


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