Thanks for the information. I have previously looked at the SE-PostgreSQL code/documentation. It was helpful and most interesting. The base DBMS I am using is called Trusted RUBIX, which is an CC EAL-4 (Trusted Solaris) evaluated MLS DBMS. We have been contracted to integrate SELinux TE and MLS (Red Hat flavor) into our DBMS. So, obviously using SE-PostgreSQL is not an option :-) In the bigger picture, this current work is a small (and rather detached) step towards a high robustness (EAL-6+) DBMS solution.

Historically, our company (and myself personally) have been involved in high(er) assurance MLS DBMS products/research for a number of years. As such, we tend to use a more "traditional" minimized trust, reference monitor architecture as opposed to inserting hooks and using query modification for our security enforcement. This means, for instance, that a label object permeates much of our kernel code at a fairly low level as well as storage objects. Thus, the runtime and storage representation must be chosen carefully as it will touch much of our kernel code. We also support full polyinstantiation of named objects, which dictates an efficient label mechanism. (Integration of TE + MLS into traditional MLS polyinstantiation behavior is an interesting topic!)

Out of curiosity, KaiGai, a question about how SE-PostgreSQL presents the security context to a user. From your security guide I see that the context is a selectable column. But, what SQL type is the column? For instance, do you define your own SQL type, such as "Security Context" or is it a VARCHAR that has special constraints placed upon it to force it to conform to the structure of a security context?

Blessings,

Andy

KaiGai Kohei wrote:

I have also considered maintaining my own internal, persistent mapping
between string based contexts and an integer representation, the mapping
being stored/indexed inside the DBMS. This gives me a small storage overhead
with a fixed size.

I don't have a problem with internal mapping like that.

In SE-PostgreSQL, it maintains own internal mapping between text represented
security context and its integer identifier. The 'pg_security' system catalog
stores the pair of them.

Any tuple (including system catalog) has its security context. It is stored
within padding area of HeapTupleHeader as an integer value, and it means the
primary key of 'pg_security' system catalog.

It also enables to boost userspace AVC, because this idea makes possible to
implement it using a relationship between identifiers (not a text representation).

When the security policy is reloaded and it makes invalidate the stored context,
the stored one is dealt as 'unlabeled_t'.

But, don't we already have sepostgresql? Maybe you should be looking
to see if that fits your needs or you might get ideas from the work
that they performed?

FYI:
http://code.google.com/p/sepgsql/

Andrew, what is your intended base RDBMS?

Currently, SE-PostgreSQL is the only SELinux awared RDBMS.
It is now under reviewing for the next release (v8.4) cycle.
http://wiki.postgresql.org/wiki/CommitFest:2008-07

However, I think we can apply SELinux for any other relational model implementation.

Thanks,