Re: [RFC PATCH ghak59 V1 1/6] audit: give a clue what CONFIG_CHANGE op was involved

[Richard Guy Briggs <rgb@redhat.com>]

On 2018-07-19 18:47, Paul Moore wrote:
> On Thu, Jul 19, 2018 at 12:10 PM Richard Guy Briggs <rgb@redhat.com> wrote:
> > On 2018-07-18 17:45, Paul Moore wrote:
> > > On Thu, Jul 12, 2018 at 8:43 PM Richard Guy Briggs <rgb@redhat.com> wrote:
> > > > On 2018-06-28 15:41, Paul Moore wrote:
> > > > > On Thu, Jun 14, 2018 at 4:23 PM Richard Guy Briggs <rgb@redhat.com> wrote:
> > > > > > The failure to add an audit rule due to audit locked gives no clue
> > > > > > what CONFIG_CHANGE operation failed.
> > > > > > Similarly the set operation is the only other operation that doesn't
> > > > > > give the "op=" field to indicate the action.
> > > > > > All other CONFIG_CHANGE records include an op= field to give a clue as
> > > > > > to what sort of configuration change is being executed.
> > > > > >
> > > > > > Since these are the only CONFIG_CHANGE records that that do not have an
> > > > > > op= field, add them to bring them in line with the rest.
> > > > >
> > > > > Normally this would be an immediate reject because this patch inserts
> > > > > a field into an existing record, but the CONFIG_CHANGE record is so
> > > > > variable (supposedly bad in its own right) that I don't this really
> > > > > matters.
> > > > >
> > > > > With that out of the way, I think this patch is fine, but I don't
> > > > > think it is complete.  At the very least there is another
> > > > > CONFIG_CHANGE record in audit_watch_log_rule_change() that doesn't
> > > > > appear to include an "op" field.  If we want to make sure we have an
> > > > > "op" field in every CONFIG_CHANGE record, let's actually add them all
> > > > > :)
> > > >
> > > > The version I'm looking at already had it when it was added in 2009.
> > >
> > > Yup, there it is ... now I'm wondering what tree I was looking at as a
> > > reference while reviewing this?
> > >
> > > /me scratches head
> > >
> > > > This one doesn't add the auid and ses fields because they will be
> > > > covered by the linking of this record with the syscall record via the
> > > > audit_context() introduced in another patch.
> > >
> > > Yeah, I'm not concerned about that for the reasons you state.
> > >
> > > > > and one more in audit_receive_msg().  There may be more.
> > > >
> > > > I believe they're covered by other patches in the ghak59 set.
> > >
> > > If they are in the later patches it might be good to move those "op="
> > > additions into this patch.
> >
> > I don't see any CONFIG_CHANGE records generated in audit_receive_msg()
> > that are missing op= field.  Can you narrow it down?
> 
> Well, just grep'ing my way through audit_receive_msg() I see that
> AUDIT_ADD/DEL_RULE generates a CONFIG_CHANGE record.

The failure case is addressed in this patch.  The success case is
addressed in audit_log_rule_change().  The latter already has it.  What
is the problem?  What tree are you looking at?  What am I missing?

> > > > > > Old records:
> > > > > > type=CONFIG_CHANGE msg=audit(1519812997.781:374): pid=610 uid=0 auid=0 ses=1 subj=... audit_enabled=2 res=0
> > > > > > type=CONFIG_CHANGE msg=audit(2018-06-14 14:55:04.507:47) : audit_enabled=1 old=1 auid=unset ses=unset subj=... res=yes
> > > > > >
> > > > > > New records:
> > > > > > type=CONFIG_CHANGE msg=audit(1520958477.855:100): pid=610 uid=0 auid=0 ses=1 subj=... op=add_rule audit_enabled=2 res=0
> > > > > >
> > > > > > type=CONFIG_CHANGE msg=audit(2018-06-14 14:55:04.507:47) : op=set audit_enabled=1 old=1 auid=unset ses=unset subj=... res=yes
> > > > > >
> > > > > > See: https://github.com/linux-audit/audit-kernel/issues/59
> > > > > > Signed-off-by: Richard Guy Briggs <rgb@redhat.com>
> > > > > > ---
> > > > > >  kernel/audit.c | 6 ++++--
> > > > > >  1 file changed, 4 insertions(+), 2 deletions(-)
> > > > > >
> > > > > > diff --git a/kernel/audit.c b/kernel/audit.c
> > > > > > index e7478cb..ad54339 100644
> > > > > > --- a/kernel/audit.c
> > > > > > +++ b/kernel/audit.c
> > > > > > @@ -403,7 +403,7 @@ static int audit_log_config_change(char *function_name, u32 new, u32 old,
> > > > > >         ab = audit_log_start(NULL, GFP_KERNEL, AUDIT_CONFIG_CHANGE);
> > > > > >         if (unlikely(!ab))
> > > > > >                 return rc;
> > > > > > -       audit_log_format(ab, "%s=%u old=%u", function_name, new, old);
> > > > > > +       audit_log_format(ab, "op=set %s=%u old=%u", function_name, new, old);
> > > > > >         audit_log_session_info(ab);
> > > > > >         rc = audit_log_task_context(ab);
> > > > > >         if (rc)
> > > > > > @@ -1365,7 +1365,9 @@ static int audit_receive_msg(struct sk_buff *skb, struct nlmsghdr *nlh)
> > > > > >                         return -EINVAL;
> > > > > >                 if (audit_enabled == AUDIT_LOCKED) {
> > > > > >                         audit_log_common_recv_msg(&ab, AUDIT_CONFIG_CHANGE);
> > > > > > -                       audit_log_format(ab, " audit_enabled=%d res=0", audit_enabled);
> > > > > > +                       audit_log_format(ab, " op=%s_rule audit_enabled=%d res=0",
> > > > > > +                                        msg_type == AUDIT_ADD_RULE ? "add" : "remove",
> > > > > > +                                        audit_enabled);
> > > > > >                         audit_log_end(ab);
> > > > > >                         return -EPERM;
> > > > > >                 }
> > > > > > --
> > > > > > 1.8.3.1
> > > > >
> > > > > --
> > > > > paul moore
> > > > > www.paul-moore.com
> > > >
> > > > - 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
> > >
> > >
> > >
> > > --
> > > paul moore
> > > www.paul-moore.com
> >
> > - 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
> 
> 
> 
> -- 
> paul moore
> www.paul-moore.com

- 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