Hello,
I'm looking into adding support for extracting the username from client certificate's rfc822Name (from the subjectAltName extension).
The question I have is what would be the best approach to do this? Current implementation has a kind of clean code since it just goes through the subject name, extracting the values with X509_NAME_get_text_by_NID (while NID is obtained with OBJ_txt2nid). If I were to add this, it's bound to make the code a little bit more complicated since SAN's can't be retrieved in the same way.
So far in terms of options I have, I can see the following:
Create a distinct configuration option for the ssl_cert_username_field (i.e. specify something like "sanrfc822Name" to have Dovecot extract the username from the designated alternative name).
Make the current code fail-over to rfc822Name SAN if emailAddress is provided for ssl_cert_username (less invasion in code, but less flexibility as well).
Any input/recommendation/directioning is welcome. I've wanted to actually first write a patch, and then submit it, but I think it might be better to check what would be preferable by Dovecot maintainers/devs.
Best regards
-- Branko Majic Jabber: branko@majic.rs Please use only Free formats when sending attachments to me.
Бранко Мајић Џабер: branko@majic.rs Молим вас да додатке шаљете искључиво у слободним форматима.