Re: Common labeled security (comment on CALIPSO, labeled NFSv4)
Santosh Chokhani <SChokhani <at> cygnacom.com>
2009-04-03 17:36:17 GMT
Russ,
My thinking was that the features of SPIF that are not needed could be
discarded.
I was hoping that we could help the group save the baby and throw out
the bath water.
> -----Original Message-----
> From: Russ Housley [mailto:housley <at> vigilsec.com]
> Sent: Friday, April 03, 2009 12:45 PM
> To: Santosh Chokhani; saag <at> ietf.org
> Cc: labeled-nfs <at> linux-nfs.org; nfs-discuss <at> opensolaris.org;
> nfsv4 <at> ietf.org; selinux <at> tycho.nsa.gov
> Subject: Re: [saag] Common labeled security (comment on
> CALIPSO, labeled NFSv4)
>
> I really do not have time to write about all of my concerns.
> However, once you get beyond the basic classifications, the
> SPIF model breaks. They are markings that are only to be
> known to people that have the clearance for those markings,
> this leads to a SPIF distribution nightmare, as a subset of
> the real SPIF must be given out based on access (or not) to
> various compartments and such. It just does not scale.
>
> Russ
>
> At 11:22 AM 4/3/2009, Santosh Chokhani wrote:
> >As part of MISSI and DMS, in mid to late 90's we did work on
> something
> >called Security Policy Information File (SPIF).
> >
> >At high level SPIF entailed the following:
> >
> >1. It was ASN.1 based.
> >2. It permitted you to convert the machine representation to human
> >readable representation.
> >3. It permitted you to convert the human readable input to machine
> >representation.
> >4. It mapped labels (hierarchical sensitivity levels and
> >non-hierarchical categories) from one labeling policy to
> another (i.e.,
> >establish equivalency mapping) 5. It allowed you to
> constrain labels
> >since for some policies, existence of a category may mean some
> >categories, levels, may be included and/or excluded.
> >
> >Different labeling policies were indicated by different policy OID.
> >
> >Some of the concept from that work may be applicable here.
> >
> > > -----Original Message-----
> > > From: saag-bounces <at> ietf.org
> [mailto:saag-bounces <at> ietf.org] On Behalf
> > > Of Nicolas Williams
> > > Sent: Thursday, April 02, 2009 11:44 AM
> > > To: saag <at> ietf.org
> > > Cc: labeled-nfs <at> linux-nfs.org; selinux <at> tycho.nsa.gov;
> > > nfsv4 <at> ietf.org; nfs-discuss <at> opensolaris.org
> > > Subject: [saag] Common labeled security (comment on
> CALIPSO, labeled
> > > NFSv4)
> > >
> > > Over at the NFSv4 WG we've been having a discussion of a labeled
> > > NFSv4 proposal. [Note: NFSv4 WG and others cc'ed,
> > > Reply-To: set to SAAG.]
> > >
> > > An interop issue has arisen that we believe applies equally to
> > > CALIPSO (draft-stjohns-sipso-11.txt)and requires input
> from the IETF
> > > security area.
> > >
> > > The issue is: how do do nodes in a labeled
> network/application know
> > > if they agree on a common labeled security policy for a given DOI?
> > >
> > > Agreeing on a DOI is accomplished easily enough -- that's not an
> > > issue.
> > > Agreeing on what a given numeric sensitivity level or compartment
> > > bit means in a given DOI is quite another.
> > > Without a solution to this we're left with out-of-band agreement,
> > > which leaves interop in a lurch.
> > >
> > > I think we need a generic MLS and DTE labeled security policy
> > > document format that allows a DOI to define the names and numeric
> > > assignments of sensitivity levels, compartments, etcetera.
> > >
> > > We also need a way for nodes to agree that they have the
> same policy
> > > for a given DOI, or that they agree on a common subset of a DOI's
> > > policy.
> > >
> > > This last problem can be solved by use of a labeled
> security policy
> > > URI scheme that includes a version number (+ a requirement that
> > > changes be in the form of additions and obsolescence of old
> > > assignments, but not removals).
> > >
> > > To recap: I think we need a) a common MLS and DTE labeled
> security
> > > policy document format, b) a labeled security policy URI
> scheme to
> > > refer to such documents by.
> > >
> > > Given (a) and (b) NFSv4.x clients and servers would only have to
> > > exchange {DOI #, policy URI} tuples to determine whether
> they agree
> > > on a common policy.
> > >
> > > Note that CALIPSO describes how to encode and compare MLS
> labels on
> > > the wire, but it does not describe how nodes agree on the
> meaning of
> > > particular sensitivity levels or compartments. Therefore
> CALIPSO is
> > > going to have much the same problem as NFSv4.
> > >
> > > Nico
> > > --
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