Re: SSL server certificate that has an intermediary certificate in the chain

[David Hawes <dhawes@vt.edu>]

On 2011-07-30 14:14, Howard Chu wrote:
> Erwann ABALEA wrote:
>> Actual OpenLDAP configuration would be to place B (and maybe B1)
>> certificate in TLSCACertificateFile/Path element, to be able to verify
>> the Client certificate. The Server must also place A1 in this element,
>> so it can be sent to the Client to help it verify the Server
>> certificate.
> 
>> So, during the TLS negotiation, B, A1, maybe B1, maybe A are sent to
>> the Client for it to verify the Server certificate? (remember, this
>> certificate is signed by A1, and A must already be known by the
>> Client). That's a waste of bandwidth.
> 
> The TLS library doesn't do anything so stupid, it only sends the
> certificates that are part of the chain from the subject's cert up to
> the root CA.

I think the real question here is if the CA chain that the server sends
and the CA chain that the server uses to verify client certificates can
be different.

In Apache, this is done with the SSLCertificateChainFile and
SSLCACertificateFile directives.  This makes it possible to have the
server send a certificate chain that differs from the CAs it uses to
verify clients.  This is useful if you want to have a server certificate
signed by one CA, but only accept client certificates signed by another CA.

This sounds like an OpenLDAP feature request to me.