[Help-gnutls] Re: Authentication during Handshake

Simon Josefsson simon at josefsson.org
Fri May 30 11:34:28 CEST 2008

No, that is not implemented.  By reading the documentation for this, I
think GnuTLS should provide a similar callback.  Patches welcome. :)


"Rainer Gerhards" <rgerhards at gmail.com> writes:

> Just double-checking:
> As far as I have seen openSSL's SSL_CTX_set_cert_verify_callback() is
> not implemented inside the compatibility layer? I am asking because of
> http://www.ietf.org/mail-archive/web/syslog/current/msg01963.html
> Thanks,
> Rainer
> On Wed, May 21, 2008 at 1:53 PM, Nikos Mavrogiannopoulos
> <nmav at gnutls.org> wrote:
>> Rainer Gerhards wrote:
>>> Hi Nikos,
>>> On Wed, May 21, 2008 at 1:08 PM, Nikos Mavrogiannopoulos
>>> <n.mavrogiannopoulos at gmail.com> wrote:
>>>> Simon Josefsson wrote:
>>>>>> I still would see a lot of benefit in being able to check the remote
>>>>>> peers identity BEFORE the Finished message is sent. That way, I could
>>>>>> block access to not permitted peers at the risk of the DoS outlined
>>>>>> above. Am I still overlooking something?
>>>>> No, I think that is correct.  Nikos, any thoughts?  You added some
>>>>> callbacks during the handshake earlier, are any of those useful here?
>>>> No unfortunately not. The callbacks I added are called after client
>>>> hello is received. The callbacks you discuss need to be called after the
>>>> certificate message is received.
>>> Could you point me to the file where processing the certificate
>>> message is done? I would be interested to see if I could add a
>>> callback, and may it even just be to know how it is done ;)
>> The file is gnutls_handshake.c. The functions you're interested in are
>> _gnutls_handshake_client, _gnutls_handshake_server (if you're doing it
>> for both of them).
>> A similar callback is _gnutls_user_hello_func which is the post_hello
>> callback.
>> I'd glad to review and commit and patches for this issue.
>> regards,
>> Nikos

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