KaiGai,
I do not still get it, so you are going to introduce and add Mandatory
Access Control in PostgreSQL ?
I still don't get its practical application, since obviously at system
level DAC is not sufficient users have other means of bypassing it, ie.
can set things that results in undesired behavior and security breach
such as chmod 777, or out of context memory pages
So when database users are created by admins or design or such, what
SE-PostgreSQL is supposed to do?, preventing users to bypass their
privileges? or bypassing security of the DBMS engines? (the latter can
already be achieved using SELinux)
or to give people possibility of "Creating access" controls then put MAC
into practice not to let them to create insecure access !! why we have
to give them such grant of privilege at first place in DBMS
Or the goal is access control being derived from SELinux Policies
(external sources)?
in current implementations of a secure database, an external module
(Program) can add or remove or delete records to or from the database
and being moderated by SELinux for MAC and sandboxing purposes
since PostgreSQL is process based (not thread based) per connection,
what is it saved? by not isolating Databases (DBMS) totally from each
other and having multiple instances rather than just introducing another
level of access control mechanism?
Complexity is the enemy of Security.
Would you mind to shed some light on this.
Thanks
Patrick K.
On 12/8/2010 6:41 PM, KaiGai Kohei wrote:
(2010/12/09 0:29), Ted Toth wrote:
Thanks for the update. Questions inline.
2010/12/7 KaiGai Kohei<kaigai@xxxxxxxxxxxxx>:
I'd like to report the recent status of SE-PostgreSQL development,
since I guess few number of people subscribing pgsql-hackers list.
Now, the pgsql community is working on new features to the upcoming
v9.1 releases. Although we don't come up the feature freeze yet,
several fundamental features to support selinux are already merged,
and these shall be released within the v9.1 release.
The v9.1 of pgsql shall support label based mandatory access control
by external security providers.
The external security provider is a similar concept to LSM.
It allows plugin modules to make access control decision based on
its access control model such as SELinux, and the core pgsql calls
the modules via security hooks.
So, SE-PostgreSQL is now implemented as a plugin module of pgsql.
Anyway, the upcoming v9.1 shall provide a mechanism to assign
security label of database objects and security hooks on various
strategic points (but not comprehensive yet).
Could you expand upon exactly what you mean here? Since this is not
'comprehensive' does that imply potential vulnerabilities?
It means we are under construction of the security hooks, so some of
actions (especially, permission checks on ddl statements) are not
hooked by the plugin modules. In short, it is still vulnerable.
These stuff must be implemented step-by-step, because burden of
reviewers is not ignorable if we try to implement a complete
feature at once. It is a target towards the v9.2 release.
We will be able to assign security label using SECURITY LABEL
statement in SQL (original enhancement of pgsql) by hand.
It allows us to assign a certain label on a certain database
objects. The given label is validated by plugin modules, then
stored within system catalogs.
In addition, post-object-creation hook enables to assign a default
security label of the new database object on the creation time.
Here are other new hooks; 'ExecutorCheckPerms' hook enables to
make access control decision on DML statements (SELECT, UPDATE,
INSERT and DELETE), 'ClientAuthentication' hook enables to
obtain security label of the peer process using getpeercon(3)
at beginning of the session, 'object_access' hook will enable
to handle DDL permissions but not comprehensive yet.
I expect a limited functionalities will be available in the
v9.1 of PostgreSQL. It will be far from production level,
but a great step towards the full features.
The v9.1 will have feature freeze at the 15-Jun, then it may be
released half years later. At the same time, merge window to the
v9.2 will be open. So, I'll upstream rest of features; such as
comprehensive DDL permissions, row-level access controls and so on.
Thanks,
--
KaiGai Kohei<kaigai@xxxxxxxxxxxxx>
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