Problem authenticating WPA2 network: OpenSSL rejects certificate

[Jouni Malinen]

On Wed, Oct 06, 2010 at 02:23:30PM +0200, Berend Dekens wrote:
>  On 06/10/10 13:45, Berend Dekens wrote:
> > I verified the certificate with openssl and rebuild openssl with every
> > option available (and ofcourse recompiled wpa_supplicant afterwards).
> > Nothing helped.

Would you be able to send me the full certificate chain that the
authentication server is advertising, i.e., radius.utwente.nl and both
of the CyberTrust CA certificates? I don't think I have access to
anything that would allow me to test that authentication server easily
(well, apart from driving somewhere that has eduroam network and trying
a random @utwente.nl user name, I guess ;-). I was unable to reproduce
this with my own test certificates that I tried to make look like the
CyberTrust chain at least as far as the root CA is concerned.

> > Since OpenSSL attempts to verify the certificate itself (which is
> > impossible as it is the root CA), it looks to me like a bug in
> > wpa_supplicant or OpenSSL. Afaik it is impossible to verify a root CA
> > certificate as there is nobody able to 'claim' the certificate as being
> > signed by them.

Well, you can verify that the root CA meets whatever criteria is placed
on CA certificates, but yes, OpenSSL should figure out that the CA cert
is the trusted one and not try to find an issuer. I do not think there
is anything in wpa_supplicant that would cause this behavior, so this
would require OpenSSL debugging with the particular certificate chain.

> I just found a solution after I found out that OpenSSL is preferred over
> GnuTLS (when available). Since OpenSSL kept throwing a tantrum, I
> decided to disable OpenSSL entirely and include GnuTLS instead.
> 
> Lo and behold: it works! So I'd say there is some serious problem in
> OpenSSL that prevents root certificates being accepted as such. Is this
> a known issue?

Interesting.. I don't know whether this is a known issue or whether it
would be even considered an issue, i.e., OpenSSL may have good reasons
to not accept that root CA certificate.. MD5 protected certificate from
1998 is not exactly what I would consider to be of that good security
nowadays.

-- 
Jouni Malinen                                            PGP id EFC895FA