Re: [RFC][PATCH] selinux: Report result in avc messages

[Eric Paris <eparis@redhat.com>]

Acked-by: Eric Paris <eparis@redhat.com>

On Wed, 2014-04-30 at 08:38 -0700, Stephen Smalley wrote:
> Attached patch switches to reporting permissive=0|1 and only does it
> for avc: denied messages.
> 
> On Wed, Apr 30, 2014 at 8:18 AM, Stephen Smalley
> <stephen.smalley@gmail.com> wrote:
> > I could make it permissive=0 or permissive=1 if that is less
> > confusing.  It doesn't necessarily correspond to the result of the
> > system call, just the avc_has_perm call, as e.g. the kernel checks
> > CAP_DAC_OVERRIDE and falls back to CAP_DAC_READ_SEARCH if only
> > read/search access was requested, and there are other cases where a
> > permission denial has a side effect rather than preventing the system
> > call (e.g. CAP_FSETID).
> >
> > On Wed, Apr 30, 2014 at 6:34 AM, Daniel J Walsh <dwalsh@redhat.com> wrote:
> >>
> >> On 04/30/2014 09:29 AM, Steve Grubb wrote:
> >>> On Wednesday, April 30, 2014 08:59:50 AM Daniel J Walsh wrote:
> >>>> How about permitted rather then allowed.
> >>> I think permitted is already in an AVC.
> >> Not sure where.
> >>>
> >>>> On 04/29/2014 10:59 PM, Eric Paris wrote:
> >>>>> On Tue, 2014-04-29 at 16:54 -0700, Stephen Smalley wrote:
> >>>>>> Requested for Android in order to distinguish denials that are not in
> >>>>>> fact breaking anything yet due to permissive domains versus denials
> >>>>>> that are being enforced, but seems generally useful.  result field was
> >>>>>> already in the selinux audit data structure and was being passed to
> >>>>>> avc_audit() but wasn't being used.  Seems to cause no harm to ausearch
> >>>>>> or audit2allow to add it as a field.  Comments?
> >>>>> I think it's a great idea, but I'm worried that Steve is going to get
> >>>>> grumpy because an AVC record is going to have a result= field which is
> >>>>> similar, but not necessarily related to the res= field of a SYSCALL
> >>>>> record.
> >>> I think that I'll have to parse this field no matter what. Its probably that
> >>> important. In the syscall, we use success= to be the final determination.
> >>>
> >>>
> >>>>> Seems easily confused (although probably 9999 times out of
> >>>>> 10000 they will be the same)
> >>> Why would this ever not be correct? Are there times when we get an AVC with a
> >>> denial _and_ the syscall completes successfully?
> >>>
> >>> I'd suggest using res= since its in the audit dictionary and means exactly
> >>> what you are wanting to use it for. In it, 1 is success, 0 is failure.
> >>>
> >> I have seen AVC's where the success=yes in enforcing mode.  Basically
> >> the kernel takes a different code path and the syscall succeeds.  Most
> >> of these end up as dontaudits.
> >>>>> So while I wholeheartedly think we should take the idea, I wonder if
> >>>>> someone can dream up a name that isn't confusingly similar...
> >>>>>
> >>>>> I can't think of anything...
> >>> There is thesaurus.com. :-)
> >>>
> >>> consequence, outcome, effect, reaction,  conclusion, verdict, decision,
> >>> judgement, finding, ruling, answer, solution, recommendation, order,  ...
> >>>
> >>> -Steve
> >>