Re: [PATCH V3 0/3] Add support for session ID user filtering

[Richard Guy Briggs]

On 2016-10-20 15:27, Paul Moore wrote:
> On Thursday, August 18, 2016 01:43:12 PM Richard Guy Briggs wrote:
> > https://github.com/linux-audit/audit-kernel/wiki/RFE-Session-ID-User-Filter
> > RFE Session ID User Filter
> > 
> > https://github.com/linux-audit/audit-kernel/issues/4
> > RFE: add a session ID filter to the kernel's user filter
> > 
> > See also the set of userspace suport patches:
> > 	Add support for sessionid user filters, sessionid_set and loginuid_set
> > 	https://www.redhat.com/archives/linux-audit/2016-August/msg00005.html
> > 	(userspace update expected to be posted 2016-08-18)
> > and the test case:
> > 	https://github.com/rgbriggs/audit-testsuite/tree/ghak4-test-for-sessionID-u
> > ser-filter
> > 
> > This third patch is expected to have a merge conflict with:
> > 	"audit: add exclude filter extension to feature bitmap"
> > posted on 2016-08-18.
> > 
> > Richard Guy Briggs (3):
> >   audit: add support for session ID user filter
> >   audit: add AUDIT_SESSIONID_SET support
> >   audit: add sessionid filter extension to feature bitmap
> > 
> >  include/linux/audit.h      |   10 ++++++++++
> >  include/uapi/linux/audit.h |    6 +++++-
> >  kernel/auditfilter.c       |    5 +++++
> >  kernel/auditsc.c           |    6 ++++++
> >  4 files changed, 26 insertions(+), 1 deletions(-)
> 
> In light of our current decision to drop the session ID "set" filter, I'm 
> taking another look at these patches and Richard's comment to simply drop 
> patch 2/3 and apply 1/3 and 3/3.
> 
> Richard, as I mentioned earlier, perhaps not clearly enough, I think we should 
> put a check in audit_set_loginuid() to skip the (int)-1 value from appearing 
> in session_id during normal operation.  In other words, roll/reset the value 
> in session_id one value early so we don't run into problems with the (int)-1 
> unset sentinel value.

I noted your comment earlier and I agree skipping the sentinel is
required, but if we are rolling this counter, we have bigger issues
unless there is a way to determine if a sessionID value is still in use
by at least one task.

> paul moore

- RGB

--
Richard Guy Briggs <rgb@xxxxxxxxxx>
Kernel Security Engineering, Base Operating Systems, Red Hat
Remote, Ottawa, Canada
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