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Antw: Quick question about OpenLDAP Server CA certificate handling



>>> Mark Cairney <Mark.Cairney@ed.ac.uk> schrieb am 11.04.2019 um 13:35 in
Nachricht <aae98896-e973-bae1-8eaa-d4a7fa6d29dd@ed.ac.uk>:
> Hi,
> 
> Having just updated our SSL certificates on our OpenLDAP server led us
> to review the contents of our "bundle" file referenced in
> "olcTLSCACertificateFile".
> 
> According to the documentation at:
> https://www.openldap.org/doc/admin24/tls.html it states "This directive
> specifies the PEM-format file containing certificates for the CA's that
> slapd will trust. The certificate for the CA that signed the server
> certificate must be included among these certificates. If the signing CA
> was not a top-level (root) CA, certificates for the entire sequence of
> CA's from the signing CA to the top-level CA should be present. Multiple
> certificates are simply appended to the file; the order is not significant."
> 
> However based on our understanding of how SSL works we should only
> actually need the intermediate(s) in there as the client should have the
> root and then compare the intermediate provided by the server and only
> trust it if it can use this in conjunction with it's copy of the root
> certificate to complete the chain of trust.

With the same argumentation you could also omit the intermediate CAs (you can trust an intermediate CA as well).

> 
> Based on this we configure our web servers to only have the
> intermediate(s) in their chain (and in fact SSL Labs marks you down if
> you have the root in there too).
> 
> Of course we do realise LDAP is not HTTP!
> 
> We're running OpenLDAP 2.4.47 linked against OpenSSL on Scientific Linux
> 7.5.
> 
> Kind regards,
> Mark
> 
> -- 
> /****************************
> 
> Mark Cairney
> ITI Enterprise Services
> Information Services
> University of Edinburgh
> 
> Tel: 0131 650 6565
> Email: Mark.Cairney@ed.ac.uk 
> PGP: 0x435A9621
> 
> *******************************/
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