Introduced password caching on authenticated sessions

This is to prepare eurephia-auth plugin to use other and
more CPU intensive hashing algorithms for passwords. In addition,
open sessions will now not be rejected/closed due to wrong
password if the user changes the password with an open session
running.

The patch adds a new server_salt attribute in the eurephiaCTX
structure.  This is used as a temporary salt and is created of
random data when OpenVPN is started.

When a user is being authenticated (eurephia.c/eurephia_userauth)
a authentication session (not the same as a 'normal' session) is
opened and checked for a cached password.  If it does not exist
or match, normal password check will be done against the user
database.  If a cached password is found and matches, it is
considered to be authenticated.

The cached password uses the SHA512 algorithm, together with the
eurephiaCTX->server_salt.

0 files changed, 0 insertions, 0 deletions