Re: [RFC PATCH ghak59 V1 3/6] audit: exclude user records from syscall context

[Paul Moore]

On Tue, Jul 24, 2018 at 9:05 AM Richard Guy Briggs <rgb@xxxxxxxxxx> wrote:
> On 2018-07-23 17:00, Paul Moore wrote:
> > On Mon, Jul 23, 2018 at 12:43 PM Richard Guy Briggs <rgb@xxxxxxxxxx> wrote:
> > > On 2018-07-12 17:46, Richard Guy Briggs wrote:
> > > > On 2018-06-28 18:11, Paul Moore wrote:
> > > > > On Thu, Jun 14, 2018 at 4:23 PM Richard Guy Briggs <rgb@xxxxxxxxxx> wrote:
> > > > > > Since the function audit_log_common_recv_msg() is shared by a number of
> > > > > > AUDIT_CONFIG_CHANGE and the entire range of AUDIT_USER_* record types,
> > > > > > and since the AUDIT_CONFIG_CHANGE message type has been converted to a
> > > > > > syscall accompanied record type, special-case the AUDIT_USER_* range of
> > > > > > messages so they remain standalone records.
> > > > > >
> > > > > > See: https://github.com/linux-audit/audit-kernel/issues/59
> > > > > > Signed-off-by: Richard Guy Briggs <rgb@xxxxxxxxxx>
> > > > > > ---
> > > > > >  kernel/audit.c | 12 +++++++++---
> > > > > >  1 file changed, 9 insertions(+), 3 deletions(-)
> > > > >
> > > > > I think this is fine, but see my previous comment about combining 2/6
> > > > > and 3/6 as a safety measure.
> > > >
> > > > This one I left as a seperate patch for discussion.  We'd previously
> > > > talked about connecting all possible records with syscall records if
> > > > they exist, but this one I'm unsure about, since we don't really care
> > > > what userspace process is issuing this message.  It is just the message
> > > > content itself that is important.  Or is it?  Are we concerned about
> > > > CAP_AUDIT_WRITE holders/abusers and want as much info about them as we
> > > > can get in case they go rogue or pear-shaped?
> > >
> > > I'm waiting on re-spinning this patchset because of this open question.
> > >
> > > Is connecting AUDIT_USER* records desirable or a liability?
> >
> > Like I said, I think special casing the AUDIT_USER* records so they
> > are *not* associated with other records is okay, and perhaps even the
> > right thing to do.  The problem is that we don't have the necessary
> > context (har har) to match any kernel events (and there is the
> > possibility that there are none) to the userspace generated
> > AUDIT_USER* event.  Further, I don't think this is something we would
> > ever be able to solve in a reasonable manner.
>
> Ok, having said that, I think I'd still prefer to keep this patch
> seperate, partly to retain the simplicity of the previous patch and make
> very clear what each one is doing, and partly if we decide to change our
> mind in the future that these AUDIT_USER* records should be autonomous.

Okay, I'll buy that argument.

-- 
paul moore
www.paul-moore.com