[Babel-users] Reworked implementation of HMAC authentication

[Dave Taht]

On Fri, Mar 8, 2019 at 4:00 PM Juliusz Chroboczek <jch at irif.fr> wrote:
>
> Hi,
>
> I've finally gotten my act together, and reworked Clara's and Weronika's
> implementation of Babel-HMAC.  You can get the code by doing
>
>     git clone -b hmac --recurse-submodules https://github.com/jech/babeld

Yea! I'll try to clear some time to play with this before ietf. No
promises though, I'm frantically busy on other stuff.

>
> While this code is almost completely untested, it is meant to eventually
> implement the protocol described in
>
>     https://tools.ietf.org/html/draft-ietf-babel-hmac
>
> Known issues:
>
>   - no interop testing has been done yet;
>   - we create a neighbour entry too early, which makes us vulnerable to DoS;
>   - we compute HMAC for each TLV, rather than just once for the whole
>     packet, which, again, makes us vulnerable to DoS;

ugh.

>   - we don't timeout neighbours properly, which makes us vulnerable to
>     delayed packets;
>   - we only support sending one HMAC (receiving multiple HMACs should
>     work, but for obvious reasons it's untested);
>   - we don't support key rotation.

Sigh.

Still, happy to see it! Thanks very much!

>
> You can test this code by saying something like:
>
>     babeld -C 'key id test type sha256 value ebf49e6fbc6414aa567e30891846e96963cdda73289b9cd245d67ff9d281abc0' -C 'interface eth0 hmac test'
>
> The "key" stanza defines a key of type sha256, with the value given as
> a 32 byte-long hex key. The "interface" stanza enables the key on the
> interface eth0.
>
> In addition to "type sha256", we support "type blake2s", which requires
> a 16 byte-long key.
>
> -- Juliusz
>
>
>
>
>
>
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-- 

Dave Täht
CTO, TekLibre, LLC
http://www.teklibre.com
Tel: 1-831-205-9740