question about auth implementation

[Dan Ellison]

Hello,

The company I work for has been using Cyrus IMAP for several years with no 
problems.  However, due to some new security policies, we have to make some 
changes in how we're authenticating.

After reading the SASL docs and examining some of the plugin code, it appears 
to me that what I need is to be able to handle the password validation for the 
PLAIN and LOGIN authentication methods.

I've looked at the plugin that implements the PLAIN method (code in 
plugins/plain.c), and it looks like I could modify that code into a new plugin 
that will do what I need.  However, I have been unable to find the code that 
handles the password validation for the LOGIN auth.  I have tried modifying 
the LOGIN plugin in plugins/login.c, but as far as I can tell, it isn't being 
used.

I don't have any previous experience using SASL, so I admit that I may have 
missed something that should have been obvious.

Can anyone give me a suggestion on where to go from here?    If possible, I'd 
like to confine any coding to plugins or other external routines so that I 
don't have to change any of the IMAP or SASL routines.

Any information on where the implementation of the IMAP LOGIN method in the 
source would be appreciated as well.

Thanks
Dan Ellison