Re: [PATCH ghak90 V6 08/10] audit: add containerid filtering

[Richard Guy Briggs]

On 2019-05-29 18:16, Paul Moore wrote:
> On Mon, Apr 8, 2019 at 11:41 PM Richard Guy Briggs <rgb@xxxxxxxxxx> wrote:
> >
> > Implement audit container identifier filtering using the AUDIT_CONTID
> > field name to send an 8-character string representing a u64 since the
> > value field is only u32.
> >
> > Sending it as two u32 was considered, but gathering and comparing two
> > fields was more complex.
> >
> > The feature indicator is AUDIT_FEATURE_BITMAP_CONTAINERID.
> >
> > Please see the github audit kernel issue for the contid filter feature:
> >   https://github.com/linux-audit/audit-kernel/issues/91
> > Please see the github audit userspace issue for filter additions:
> >   https://github.com/linux-audit/audit-userspace/issues/40
> > Please see the github audit testsuiite issue for the test case:
> >   https://github.com/linux-audit/audit-testsuite/issues/64
> > Please see the github audit wiki for the feature overview:
> >   https://github.com/linux-audit/audit-kernel/wiki/RFE-Audit-Container-ID
> > Signed-off-by: Richard Guy Briggs <rgb@xxxxxxxxxx>
> > Acked-by: Serge Hallyn <serge@xxxxxxxxxx>
> > Acked-by: Neil Horman <nhorman@xxxxxxxxxxxxx>
> > Reviewed-by: Ondrej Mosnacek <omosnace@xxxxxxxxxx>
> > ---
> >  include/linux/audit.h      |  1 +
> >  include/uapi/linux/audit.h |  5 ++++-
> >  kernel/audit.h             |  1 +
> >  kernel/auditfilter.c       | 47 ++++++++++++++++++++++++++++++++++++++++++++++
> >  kernel/auditsc.c           |  4 ++++
> >  5 files changed, 57 insertions(+), 1 deletion(-)
> 
> ...
> 
> > diff --git a/kernel/auditfilter.c b/kernel/auditfilter.c
> > index 63f8b3f26fab..407b5bb3b4c6 100644
> > --- a/kernel/auditfilter.c
> > +++ b/kernel/auditfilter.c
> > @@ -1206,6 +1224,31 @@ int audit_comparator(u32 left, u32 op, u32 right)
> >         }
> >  }
> >
> > +int audit_comparator64(u64 left, u32 op, u64 right)
> > +{
> > +       switch (op) {
> > +       case Audit_equal:
> > +               return (left == right);
> > +       case Audit_not_equal:
> > +               return (left != right);
> > +       case Audit_lt:
> > +               return (left < right);
> > +       case Audit_le:
> > +               return (left <= right);
> > +       case Audit_gt:
> > +               return (left > right);
> > +       case Audit_ge:
> > +               return (left >= right);
> > +       case Audit_bitmask:
> > +               return (left & right);
> > +       case Audit_bittest:
> > +               return ((left & right) == right);
> > +       default:
> > +               BUG();
> 
> A little birdy mentioned the BUG() here as a potential issue and while
> I had ignored it in earlier patches because this is likely a
> cut-n-paste from another audit comparator function, I took a closer
> look this time.  It appears as though we will never have an invalid op
> value as audit_data_to_entry()/audit_to_op() ensure that the op value
> is a a known good value.  Removing the BUG() from all the audit
> comparators is a separate issue, but I think it would be good to
> remove it from this newly added comparator; keeping it so that we
> return "0" in the default case seems reasoanble.

Fair enough.  That BUG(); can be removed.

> > +               return 0;
> > +       }
> > +}
> 
> --
> paul moore
> www.paul-moore.com

- RGB

--
Richard Guy Briggs <rgb@xxxxxxxxxx>
Sr. S/W Engineer, Kernel Security, Base Operating Systems
Remote, Ottawa, Red Hat Canada
IRC: rgb, SunRaycer
Voice: +1.647.777.2635, Internal: (81) 32635