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Date:   Tue, 10 Nov 2020 22:03:59 -0500
From:   Richard Guy Briggs <rgb@redhat.com>
To:     Paul Moore <paul@paul-moore.com>
Cc:     Alex Shi <alex.shi@linux.alibaba.com>, linux-audit@redhat.com,
        linux-kernel@vger.kernel.org
Subject: Re: [PATCH] audit: remove unused macros
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On 2020-11-10 21:47, Paul Moore wrote:
> On Tue, Nov 10, 2020 at 10:23 AM Richard Guy Briggs <rgb@redhat.com> wrote:
> > On 2020-11-06 16:31, Alex Shi wrote:
> > > Some unused macros could cause gcc warning:
> > > kernel/audit.c:68:0: warning: macro "AUDIT_UNINITIALIZED" is not used
> > > [-Wunused-macros]
> > > kernel/auditsc.c:104:0: warning: macro "AUDIT_AUX_IPCPERM" is not used
> > > [-Wunused-macros]
> > > kernel/auditsc.c:82:0: warning: macro "AUDITSC_INVALID" is not used
> > > [-Wunused-macros]
> > >
> > > remove them to tame gcc.
> > >
> > > Signed-off-by: Alex Shi <alex.shi@linux.alibaba.com>
> > > Cc: Paul Moore <paul@paul-moore.com>
> > > Cc: Eric Paris <eparis@redhat.com>
> > > Cc: linux-audit@redhat.com
> > > Cc: linux-kernel@vger.kernel.org
> > > ---
> > >  kernel/audit.c   | 1 -
> > >  kernel/auditsc.c | 3 ---
> > >  2 files changed, 4 deletions(-)
> > >
> > > diff --git a/kernel/audit.c b/kernel/audit.c
> > > index ac0aeaa99937..dfac1e0ca887 100644
> > > --- a/kernel/audit.c
> > > +++ b/kernel/audit.c
> > > @@ -65,7 +65,6 @@
> > >  /* No auditing will take place until audit_initialized == AUDIT_INITIALIZED.
> > >   * (Initialization happens after skb_init is called.) */
> > >  #define AUDIT_DISABLED               -1
> > > -#define AUDIT_UNINITIALIZED  0
> > >  #define AUDIT_INITIALIZED    1
> > >  static int   audit_initialized;
> >
> > This one is part of a set, so it feels like it should stay, but the code
> > is structured in such a way that it is not necessary.
> 
> Yes, I'd like for us to find a way to keep this if possible.  Let's
> simply initialize "audit_initialized" to AUDIT_UNINITIALIZED in this
> file.  At some point someone will surely complain about not needing to
> initialize to zero, but we can deal with that later.

We could change them to an enum of 1,2,3.  ;-)

> > > diff --git a/kernel/auditsc.c b/kernel/auditsc.c
> > > index 183d79cc2e12..eeb4930d499f 100644
> > > --- a/kernel/auditsc.c
> > > +++ b/kernel/auditsc.c
> > > @@ -80,7 +80,6 @@
> > >  #include "audit.h"
> > >
> > >  /* flags stating the success for a syscall */
> > > -#define AUDITSC_INVALID 0
> > >  #define AUDITSC_SUCCESS 1
> > >  #define AUDITSC_FAILURE 2
> >
> > Same here, but this one should really be fixed by using
> > AUDITSC_INVALID as the value assigned to context->return_valid in
> > __audit_free() to avoid using magic numbers.
> 
> Agreed.
> 
> We could probably explicitly set it in audit_alloc_context() as well
> if we wanted to be complete.

Agreed.

> > Similarly, the compared
> > values in audit_filter_rules() under the AUDIT_EXIT and AUDIT_SUCCESS
> > cases should be "ctx->return_valid != AUDITSC_INVALID" rather than just
> > "ctx->return_valid".  Same in audit_log_exit().
> 
> Agreed.
> 
> > > @@ -102,8 +101,6 @@ struct audit_aux_data {
> > >       int                     type;
> > >  };
> > >
> > > -#define AUDIT_AUX_IPCPERM    0
> > > -
> >
> > Hmmm, this one looks like it was orphaned 15 years ago a couple of
> > months after it was introduced due to this commit:
> > c04049939f88 Steve Grubb <sgrubb@redhat.com> 2005-05-13
> >     ("AUDIT: Add message types to audit records")
> >
> > Introduced here:
> > 8e633c3fb2a2 David Woodhouse <dwmw2@shinybook.infradead.org> 2005-03-01
> >     ("Audit IPC object owner/permission changes.")
> >
> > I agree, remove it.
> 
> No arguments from me.
> 
> --
> paul moore

- RGB

--
Richard Guy Briggs <rgb@redhat.com>
Sr. S/W Engineer, Kernel Security, Base Operating Systems
Remote, Ottawa, Red Hat Canada
IRC: rgb, SunRaycer
Voice: +1.647.777.2635, Internal: (81) 32635