CVS security/access control tools

[Eamonn Ryan]

Hi,
I am looking for either a commercial or open source tool for managing the 
access to a CVS repository. I would like to be able to authenticate users and 
restrict them to a certain directory, file, branch etc based on their role.
 
I know WANdisco provides something like this type of capability, but I am 
wondering if anyone knows of other tools that also provide similiar capability?
 
Thanks.