<div>Hi,</div>
<div> </div>
<div>Klaus, i think that you hit the fountain of truth :)</div>
<div>As of now, ser-tls only provides transport layer authentication. Not more. Who is allowed to authenticate? all those you trust, that is, all those with the cert signed by the CAs you trust. If you picked a ruthless CA that would give away certs to
<a href="http://hacking.incorporated.com">hacking.incorporated.com</a> ... sorry :)</div>
<div> </div>
<div>Now, for sip message authentication and authorization you need to lift the authentication information from TLS up to the application (ser). It is not difficult, it just needs a few lines of code for that (all the certs exchanged are within reach for as long as the tls connection stays up). Here is where the tls_tools module's functions (to be written) come into play:
</div>
<div>- tls_check_from/to()</div>
<div>- tls_check_cn_trusted()</div>
<div>- ... <br><br>So, let's say we want to set up a tls test network (which we do).</div>
<div>We don't want to pay for the certs, so we should generate a root cert (say, "<a href="http://openser.org">openser.org</a>"). It would be even better if some nice CA whose cert is signed by a recognized root would do sign that for us ... anyone with connections? :) This would ease transition and compatibility issues ...
</div>
<div>The root cert provides certs for each domain (providerX.com, providerY.net, ... )</div>
<div>Now, we all can authenticate each other.</div>
<div>With the tools for sip authentication and authorization, you can decide who you allow to do what in your proxy ...</div>
<div> </div>
<div>Regards,</div>
<div> </div>
<div>Cesc</div>
<div> </div>
<div><span class="gmail_quote">On 10/12/05, <b class="gmail_sendername">Klaus Darilion</b> <<a href="mailto:klaus.mailinglists@pernau.at">klaus.mailinglists@pernau.at</a>> wrote:</span>
<blockquote class="gmail_quote" style="PADDING-LEFT: 1ex; MARGIN: 0px 0px 0px 0.8ex; BORDER-LEFT: #ccc 1px solid">Nils Ohlmeier wrote:<br>> Klaus, if you do not trust <a href="http://badguy.com">badguy.com</a> although he has a valid singed
<br>> certificate from a CA which you trust, then you can throw away TLS<br>> completely.<br><br>There is a big difference between authentication and authorization.<br><br>1. I have to authenticate the peer. Using TLS and certifiactes is fine.
<br><br>2. I have to authorize the peer. Some peers will be e.g. routed<br>different. You would this this like:<br> if (message is from trusted peer) {<br> ....<br><br>So I need to check the certificate in ser.cfg somehow, or associate the
<br>domain in the From header with the domain in the certificate.<br><br>Or do I miss the point?<br><br>regards<br>klaus<br><br>> The hole model only works because the trust in inherited from the CA when you<br>> get a singed certificate.
<br>> If you do not trust any CA, except your own, then you created your own trust<br>> database which is hard to maintain. No matter what is the base of the<br>> trustworthyness (IP; certificate signed by you; shared secret or signed
<br>> certificate for IPSec) maintaining the trust database (or however you call<br>> it) is a real pain, that is the reason why you should trust someone else to<br>> do this job.<br>><br></blockquote></div>