Re: [Weechat-dev] ssl_fingerprint irc server option

[Sébastien Helleu]

On Mon, Jan 20, 2014 at 04:40:55AM +0100, Maarten de Vries wrote:
>    Currently, the only way to use a self-signed certificate for an IRC server 
> (or bouncer) is to add the certificate to the root certificate list
>    or to disable certificate verification all together.
> 
>    Adding it to the root CA list means that other certificate signed with the 
> matching private key will also be accepted, which is not desirable
>    since it could be used to forge certificates for existing servers when 
> compromised. Additionally, there is only one global setting for which
>    root CA list to use, and it can't be set per server. That means that you'd 
> have to either add the certificate to your distribution's CA list or
>    keep a copy in in sync somewhere with the added certificate. Adding it to 
> your distribution's CA list would even compromise https and other
>    applications if the private key was ever stolen, so this would be a very 
> bad idea™. Keeping a copy in sync is just a hassle, although it can no
>    doubt be automated.
> 
>    Disabling certificate verification entirely means you are vulnerable to 
> man-in-the-middle attacks again, which means the whole purpose of
>    SSL/TLS is kind of defeated. Sure, the traffic is encrypted, but with 
> enough effort it can still be eavesdropped on.
> 
>    A much better option, in my opinion, is to allow the user to specify 
> exactly which certificate is allowed for a specific server. That way you
>    can use a self-signed certificate without fear of compromising traffic to 
> other server and without being susceptible to man-in-the-middle
>    attacks. To keep things easy (for the implementation and for the user) I 
> think that a sha1 fingerprint of the certificate is enough to identify
>    the certificate uniquely and safely.
> 
>     I added an option irc.server.*.ssl_fingerprint . When set and not an 
> empty string, the only certificate accepted for the server is the one with
>    that fingerprint. It should be the SHA1 hash of the certificate without 
> separators between the bytes, exactly in the format as shown when
>    connecting to the server. Otherwise valid certificates that have been 
> signed by a trusted CA will not be accepted if this option is non-empty,
>    unless of course the fingerprint matches.
>    I attached the patch. I hope I followed the coding style. Any comments or 
> remarks are welcome.

Hi Maarten,

Thank you for the patch!

There is a task for this feature on savannah, could you please attach the patch
to the task (with a short comment to explain what it does):

https://savannah.nongnu.org/task/?12724

Thank you.

Cordialement / Best regards.

--
Sébastien Helleu

web: flashtux.org / weechat.org      mail: address@hidden
irc: FlashCode @ irc.freenode.net    xmpp: address@hidden

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