[PATCH] audit: skip sessionid sentinel value when auto-incrementing

[Richard Guy Briggs]

On 2016-11-14 15:17, Paul Moore wrote:
> On Thu, Nov 10, 2016 at 1:41 AM, Richard Guy Briggs <rgb at redhat.com> wrote:
> > The value (unsigned int)-1 is used as a sentinel to indicate the
> > sessionID is unset.  Skip this value when the session_id value wraps.
> >
> > Signed-off-by: Richard Guy Briggs <rgb at redhat.com>
> > ---
> >  kernel/auditsc.c |    5 ++++-
> >  1 files changed, 4 insertions(+), 1 deletions(-)
> 
> Since we haven't merged the session ID kernel patches into audit#next
> yet, why don't you just squash this patch in with the session ID patch
> and resubmit upstream in one nice neat patch.

This was an existing bug regardless of new functionality added, so the
fix should not be buried in a new feature patch.

> > diff --git a/kernel/auditsc.c b/kernel/auditsc.c
> > index 5abf1dc..e414dfa 100644
> > --- a/kernel/auditsc.c
> > +++ b/kernel/auditsc.c
> > @@ -2025,8 +2025,11 @@ int audit_set_loginuid(kuid_t loginuid)
> >                 goto out;
> >
> >         /* are we setting or clearing? */
> > -       if (uid_valid(loginuid))
> > +       if (uid_valid(loginuid)) {
> >                 sessionid = (unsigned int)atomic_inc_return(&session_id);
> > +               if (unlikely(sessionid == (unsigned int)-1))
> > +                       sessionid = (unsigned int)atomic_inc_return(&session_id);
> > +       }
> >
> >         task->sessionid = sessionid;
> >         task->loginuid = loginuid;
> 
> paul moore

- RGB

--
Richard Guy Briggs <rgb at redhat.com>
Kernel Security Engineering, Base Operating Systems, Red Hat
Remote, Ottawa, Canada
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