Re: [PATCH V4 (was V6)] audit: use macros for unset inode and device values

From: Steve Grubb
Date: Wed Aug 05 2015 - 16:08:28 EST


On Wednesday, August 05, 2015 03:16:58 PM Paul Moore wrote:
> On Wednesday, August 05, 2015 02:30:14 AM Richard Guy Briggs wrote:
> > On 15/08/04, Paul Moore wrote:
> > > On Saturday, August 01, 2015 03:42:23 PM Richard Guy Briggs wrote:
> > > > Signed-off-by: Richard Guy Briggs <rgb@xxxxxxxxxx>
> > > > ---
> > > >
> > > > include/uapi/linux/audit.h | 2 ++
> > > > kernel/audit.c | 2 +-
> > > > kernel/audit_watch.c | 8 ++++----
> > > > kernel/auditsc.c | 6 +++---
> > > > 4 files changed, 10 insertions(+), 8 deletions(-)
> > >
> > > Yipee, less magic numbers!
> > >
> > > However, one question for you ... are we ever going to see a device or
> > > inode set to -1 in the userspace facing API? In other words, should the
> > > new #defines go in the uapi headers or simply in kernel/audit.h? Unless
> > > it is part of the API, let's leave it out of uapi as we have to be very
> > > careful about that stuff and I'd prefer to keep it minimal.
> >
> > This is a good point. I did briefly thing about this at one point.
> > Perhaps Steve can answer this. It would be trivial to move it back to
> > uapi if needed. Would you be ok with it in include/linux/audit.h for
> > now?
>
> I have no problem with it in include/linux/audit.h, that is a kernel-only
> include that we can change at anytime. My concern is putting it into a uapi
> header which makes it very hard to change.
>
> I'm thinking we should just go ahead and put it in include/linux/audit.h for
> now as I can't think of a reason why userspace should be passing in an
> invalid dev/inode value, it just doesn't make sense. If the invalid tokens
> prove to be valuable for userspace, we can always move the #defines.

I can't imagine anyone auditing against a specific device or inode. Its like
auditing a pid when you really want the program name. Its much more useful to
audit by filename or directory and not inode/device. So, do whatever you want.
The only unset value that people actually use is the auid because deamons have
it unset.

-Steve
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