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

[Stephen Smalley]

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 at 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 at 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
>>
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