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

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

[Adrian Byszuk]

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.
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.

Generally, the goal is to assert security of transmitting some data *without* 
losing open characteristics of mesh network.

I will very thankful for any answers.

Kind regards,
Adrian

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

[Andrew Lunn]

> 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.

For this sort of application you need end-to-end security. That is,
your end devices authenticate each other, probably using
certificates. They then negotiate a key and then encrypt all the
traffic end-to-end. It does not matter if the data leaks, since its
not practical for anybody to decode it. You then don't care about you
mesh, its just an untrusted data pipe from A to B.

You should probably get a good book on security and learn all about
what Alice and Bob need to do.

The mesh itself is not important. You cannot trust it, hence its not
important.

      Andrew

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

[Sven Eckelmann]

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

[Daniel Golle]

hi adrian,


there is no authentication, encryption whatsoever built in batman. u can use various ways to secure the services you want to run over an insecure channel like WiFi:
1. the easiest way is to use a transport layer authentication and encryption mechanism. to do this, u have to setup wpa_supplicant and set a shared key (WPA-NONE method, see wpa_supplicant docs for details about using WPA with Ad-Hoc networks). after setting up wpa_supplicant on all nodes, all traffic gets encrypted using the previously setup shared key. this method is neither elegant nor particularly flexible, and by far not as secure as "traditional" WPA2-PSK, as rekeying cannot be carried out (therefore WPA-NONE...)
the future will hopefully bring WiFi Direct, a new WiFi standard to secure Ad-Hoc networks using a one-button method (a la WPS)...
2. use IP-Layer security mechanisms (IPSec)
setup an IPSec stack in transport mode on all nodes. this method allows using individual certificates for all clients (i.e. u gonna built an PKI) and is way more flexible and by magnitudes more secure than using just a single shared secret, even when things like proper WPA in Ad-Hoc networks might come up in future.
IPSec, however, is known to be horrible to setup and imho worth the effort only if there a a few hundret to thousand participating nodes. personally, i do have some basic experience with setting up IPSec on openwrt and i can assist u if help is needed.
3. (or 2a?) built a VPN running on top of the mesh
while this might sound like an easy task on the first look -- OpenVPN can be setup within minutes -- it might not be as simple... Most VPN solutions known to me rely central infrastructure (i.e. one or more VPN server reachable for the clients)
4. secure your services, for example using using Kerberos

if u'd ask me, the best is to use either Kerberos (if possible with the services u plan to use) or IPSec transport authentication/encryption or even both (they might share one central directory service feeding both, Kerberos and IKE, but we won't get there too soon...)

good luck!


regards

daniel
On Apr 25, 2010, at 9:36 PM, 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.
> 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.
> 
> Generally, the goal is to assert security of transmitting some data *without* 
> losing open characteristics of mesh network.
> 
> I will very thankful for any answers.
> 
> Kind regards,
> Adrian

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

[Marek Lindner]

Hi,

> 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.
> 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.

I tend to agree with Andrew: If you wish to secure patient data transfers end-
to-end encryption is probably what you are looking for (e.g. SSL). But 
"ensuring security" is a very broad term which we hear quite often. Please 
check our FAQ: http://www.open-mesh.org/wiki/FAQ

Cheers,
Marek

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

[Marek Lindner]

On Monday 26 April 2010 04:13:37 Daniel Golle wrote:
> there is no authentication, encryption whatsoever built in batman. u can
>  use various ways to secure the services you want to run over an insecure
>  channel like WiFi:
>
> [..]

You wrote a pretty good summary of what is out there. Since this question 
comes up quite often can I somehow convince you to put your text in the wiki / 
user docs ? Maybe creating a new page "how to secure my mesh" ? It does not 
need to be perfect. We can improve it over time.  :-)

Cheers,
Marek

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

[Simon Wunderlich]

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Hello Adrian,

quite good answers have already been on the list. Maybe it is helpful to
create VLANs for your purpose on top of the mesh, e.g.:
 1. An open patient/customer VLAN for internet traffic etc
 2. a hospital internal VLAN for your sensitive information
 3. an administration VLAN for maintainance on your nodes

These VLANs should be configured ontop of the meshnodes and should be 
controlled by the nodes, means that the patients should not be able to 
access the internal VLAN. 

Additionally, you should secure the mesh with WPA-NONE, but as
stated before the security of this method is not well researched and 
might be weaker than WPA2/CCMP. It basically use static keys with either
TKIP or CCMP(AES).

best regards,
	Simon

On Sun, Apr 25, 2010 at 09:36:25PM +0200, 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.
> 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.
> 
> Generally, the goal is to assert security of transmitting some data *without* 
> losing open characteristics of mesh network.
> 
> I will very thankful for any answers.
> 
> Kind regards,
> Adrian
> 

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

[Adrian Byszuk]

Hello again!

First of all, I'd like to thank all of You for your answers.
They where helpful and helped me to clarify some things.
I guess it's true that I should learn a bit more about "Alice & Bob" before 
asking questions. I think I'll use IPsec or Kerberos like Daniel suggested, 
but of course firstly I'll read more about this. Anyway - Daniel I'll remember 
what you said about "openWRT" and "help" ;-)

However, I'm still concerned about issue of using fake nodes claiming they are 
someone else (e.g. sending fake OGMs) for sole reason of destroying the mesh. 
Do you think this is important issue? Can it be somehow reduced?

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

[Andrew Lunn]

> However, I'm still concerned about issue of using fake nodes
> claiming they are someone else (e.g. sending fake OGMs) for sole
> reason of destroying the mesh.  Do you think this is important
> issue? Can it be somehow reduced?

There are much simpler ways of destroying the mesh, at last
locally. e.g, my wife has a cordless telephone which operates in the
2.4GHz band. Pick up the line and wireless in the area dies. That
phone quickly got replaced with a DECT phone operating in the USA DECT
band, 1.9GHz.

2.4GHz is in the so called ISM band, industrial, scientific and
medical. Bluetooth, WiFi, microwave ovens, ZigBee, sometimes radio car
keys all work in this band, and all potentially interfere with each
other. You are working in a medical environment, so you may find that
down by radiography, you can forget WiFi all together?

You really need to tell us your use cases. Do you need a network which
has 99.999% uptime? Then dig up the road and lay fibre. Can you live
with a best effort network, which will probably die every so often,
can easily to DOSed, and performance will probably very depending on
day/night, weekday/weekend and the phase of the moon?

	   Andrew