Trusted Network File Systems
charter-ietf-tnfs-01

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.