Re: [PATCH v4 3/4] fanotify,audit: Allow audit to use the full permission event response

[Steve Grubb]

On Thursday, September 8, 2022 5:22:15 PM EDT Paul Moore wrote:
> On Thu, Sep 8, 2022 at 5:14 PM Steve Grubb <sgrubb@xxxxxxxxxx> wrote:
> > On Wednesday, September 7, 2022 4:23:49 PM EDT Paul Moore wrote:
> > > On Wed, Sep 7, 2022 at 4:11 PM Steve Grubb <sgrubb@xxxxxxxxxx> wrote:
> > > > On Wednesday, September 7, 2022 2:43:54 PM EDT Richard Guy Briggs 
wrote:
> > > > > > > Ultimately I guess I'll leave it upto audit subsystem what it
> > > > > > > wants
> > > > > > > to
> > > > > > > have in its struct fanotify_response_info_audit_rule because
> > > > > > > for
> > > > > > > fanotify subsystem, it is just an opaque blob it is passing.
> > > > > > 
> > > > > > In that case, let's stick with leveraging the type/len fields in
> > > > > > the
> > > > > > fanotify_response_info_header struct, that should give us all the
> > > > > > flexibility we need.
> > > > > > 
> > > > > > Richard and Steve, it sounds like Steve is already aware of
> > > > > > additional
> > > > > > information that he wants to send via the
> > > > > > fanotify_response_info_audit_rule struct, please include that in
> > > > > > the
> > > > > > next revision of this patchset.  I don't want to get this merged
> > > > > > and
> > > > > > then soon after have to hack in additional info.
> > > > > 
> > > > > Steve, please define the type and name of this additional field.
> > > > 
> > > > Maybe extra_data, app_data, or extra_info. Something generic that can
> > > > be
> > > > reused by any application. Default to 0 if not present.
> > > 
> > > I think the point is being missed ... The idea is to not speculate on
> > > additional fields, as discussed we have ways to handle that, the issue
> > > was that Steve implied that he already had ideas for "things" he
> > > wanted to add.  If there are "things" that need to be added, let's do
> > > that now, however if there is just speculation that maybe someday we
> > > might need to add something else we can leave that until later.
> > 
> > This is not speculation. I know what I want to put there. I know you want
> > to pin it down to exactly what it is. However, when this started a
> > couple years back, one of the concerns was that we're building something
> > specific to 1 user of fanotify. And that it would be better for all
> > future users to have a generic facility that everyone could use if they
> > wanted to. That's why I'm suggesting something generic, its so this is
> > not special purpose that doesn't fit any other use case.
> 
> Well, we are talking specifically about fanotify in this thread and
> dealing with data structures that are specific to fanotify.  I can
> understand wanting to future proof things, but based on what we've
> seen in this thread I think we are all set in this regard.

I'm trying to abide by what was suggested by the fs-devel folks. I can live 
with it. But if you want to make something non-generic for all users of 
fanotify, call the new field "trusted". This would decern when a decision was 
made because the file was untrusted or access denied for another reason.

> You mention that you know what you want to put in the struct, why not
> share the details with all of us so we are all on the same page and
> can have a proper discussion.

Because I want to abide by the original agreement and not impose opinionated 
requirements that serve no one else. I'd rather have something anyone can 
use. I want to play nice.

-Steve