Trusted Network File Systems (tnfs)

Charter
Status: Concluded January, 1996 
Chair(s):
 Fred Glover 
Description of Working Group:
The Trusted Network File  System Working Group is chartered to define 
protocol extensions to the Network File System (NFS) Version 2 protocol 
which supports network file access in a Multilevel Secure (MLS) Internet 
environment.  MLS functionality includes Mandatory Access Control (MAC),
Discretionary Access Control (DAC), authentication, auditing, documentation, 
and other items as identified in the Trusted Computer System Evaluation 
Criteria (TCSEC) and Compartmented Mode Workstation (CMW) documents.
The primary objective of this working group is to specify extensions to the 
NFS V2 protocol which support network file access between MLS systems.  It
is intended that these extensions introduce only a minimal impact on 
the existing NFS V2 environment, and that unmodified NFS V2 clients and 
servers continue to be fully supported.
Transferring information between MLS systems requires exchanging additional
security information along with the file data.  The general approach to be 
used in extending the NFS V2 protocol is to transport additional user context 
in the form of an extended NFS UNIX style credential between a Trusted NFS
(TNFS) client and server, and to map that context into the appropriate server
security policies which address file access.  In addition, file security 
attributes are to be returned with each TNFS procedure call.  Otherwise, 
the NFS V2 protocol remains essentially unchanged.
The Trusted System Interoperability Group (TSIG) has already developed a 
specification which defines a set of MLS extensions for NFS V2, and has also
planned for the future integration of Kerberos as the authentication mechanism.
The TNFS Working Group should be able to use the TSIG Trusted NFS document
as a foundation.