Hi all I'm currently testing Dovecot 2.4, considering a migration from 2.3, and all works fine except authentication against LDAP (openldap slapd) with client certificates. Which I had no problem with on 2.3 for seven years or so.
Versions: Linux Alpine 3.22 Dovecot 2.4.1-4 (7d8c0e5759) Alpine package, but patched with https://github.com/dovecot/core/commit/431e328b3b035ddb187526cd13bccf29833aed90 Now, first a Dovecot configuration that does work, unencrypted simple bind against Unix domain socket: ldap_version = 3 ldap_uris = ldapi:/// ldap_base = ou=users,dc=mydomain,dc=internal ldap_auth_dn = cn=dovecot,dc=mydomain,dc=internal ldap_auth_dn_password = secret passdb ldap { bind = no default_password_scheme = SSHA ldap_filter = (&(objectClass=posixAccount)(uid=%{user})) fields { user = %{ldap:uid} password = %{ldap:userPassword} } } Meaning I'm doing password lookups, IMAP users can authenticate against Dovecot, Postfix correctly delivers incoming emails, everything works flawlessly. Now the setup I'm talking about, which does not work: ldap_version = 3 ldap_uris = ldaps://localhost.mydomain.internal ldap_base = ou=users,dc=mydomain,dc=internal ldap_auth_sasl_mechanisms = external ssl_client_cert_file = /etc/ssl/ldap/dovecot.crt ssl_client_key_file = /etc/ssl/ldap/dovecot.key # this just as a precaution during testing, validation *does* work ssl_client_require_valid_cert = no ssl_client_ca_dir = /etc/ssl/certs passdb ldap { bind = no default_password_scheme = SSHA ldap_filter = (&(objectClass=posixAccount)(uid=%{user})) fields { user = %{ldap:uid} password = %{ldap:userPassword} } } What happens here, as far as I can see, is Dovecot connects to slapd, initiates a SASL session but then fails to send the client certificate. slapd realizes the cert isn't coming, asserts there's no other SASL "external" method to fall back to and disconnects Dovecot. Game over. Now, before somebody thinks 'maybe something wrong with the certs or so', the very same setup on the very same machine works perfectly with two other client types, namely - openldap standard utils - postfix (recipient lookup) With the utils I have this setup, with the same client cert URI ldaps://localhost.mydomain.internal BASE ou=users,dc=mydomain,dc=internal SASL_MECH external TLS_REQCERT demand TLS_CACERT /root/ssl/ca.crt TLS_CERT /etc/ssl/ldap/dovecot.crt TLS_KEY /etc/ssl/ldap/dovecot.key and ldapwhoami connects without problem, and with ldapsearch I can perform the very same searches Dovecot is supposed to do. Postfix, for recipient lookups, I have configured like this: version = 3 server_host = ldaps://localhost.mydomain.internal search_base = ou=users,dc=mydomain,dc=internal query_filter = (&(mail=%s)) result_attribute = uid bind = sasl sasl_mechs = external tls_require_cert = demand tls_ca_cert_dir = /etc/ssl/certs tls_cert = /etc/ssl/ldap/dovecot.crt tls_key = /etc/ssl/ldap/dovecot.key Again, no problem to authenticate agains LDAP with the very same client certificate. The CA is correctly installed into /etc/ssl/certs , by the way, with update-ca-certificates. So out of 3 client types with the very same setup only Dovecot fails to successfully negotiate the client cert SASL session, while, after a good look through the docs, I really don't see any other settings I could tweak. Thoughts? Greetings, Bruno _______________________________________________ dovecot mailing list -- [email protected] To unsubscribe send an email to [email protected]
