Re: [B.A.T.M.A.N.] Security & node authentication in BATMAN network

[Sven Eckelmann <sven.eckelmann@gmx.de>]

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Adrian Byszuk wrote:
> Hello,
> 
> I'm currently working on project (part of my Bachelor work) which will use
> to transfer very sensitive data over the network, and I'd like to use mesh
> networks to transfer this data. Additionally, it should also be possible
> for "normal people" to connect to this network (e.g. to surf internet).
> Preliminary, I've chosen BATMAN to build this network. But I've got a few
> questions regarding security of this solution:
> 
> 1. Does BATMAN provide any method of *authenticating* nodes?
> As I've said earlier, sometimes transferred data will be highly sensitive
> (for example: information of patients health in hospital), so it's
> absolutely critical to not allow leaking this information. I can imagine
> situation when some fake nodes claim "Hey, I'm the server collecting this
> data"... I think this is also important when someone would try to destroy
> our mesh network by placing some fake nodes in it.

No, it doesn't provide any form of authentication. Normally this should be 
done in any layer above batman-adv. As in other network setups it is possible 
to create local blackhole by a node which says that it is the perfect route or 
that he is someone else. Maybe Simon can give more information about such 
strategies.

I would say that it a good idea not to allow other nodes to join the mesh 
directly if you have mission critical data send over it.

> 2. If point nr one isn't possible, maybe there is some other way to ensure
> security? I don't know too much about security or cryptography, but I can
> think of solutions such as openVPN or IPsec.

Correct. This is the best idea to do it. To prevent others to enter the mesh 
setup it should be possible to use wpa_none. Maybe there are other suggestions 
floating around on the mailing list.
 
> Generally, the goal is to assert security of transmitting some data
> *without* losing open characteristics of mesh network.

The problem is that you have two different goals. It is ok to say that data 
must be encrypted over the mesh (vpn/ipsec/..), but it is hard to keep 
something really open and at the the same time also prevent the user to have 
control over the mesh (because the mesh is not for the nodes, but the nodes 
form the mesh).

But if it is only important that data cannot be captured by other people then 
go for a good higher level encryption and authentication strategy.

And are you sure that you really want to connect endu ser to the mesh 
directly? It is a lot easier to use dedicated nodes (ask Linus or Marek) which 
connects to the mesh and provide some kind of gateway to/over the mesh. Those 
endpoints could for example also use to provide the vpn (depends on your 
setup).

Best regards,
	Sven

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