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

[Paul Moore]

On Thu, Jul 12, 2018 at 8:43 PM Richard Guy Briggs <rgb@xxxxxxxxxx> wrote:
> On 2018-06-28 15:41, Paul Moore wrote:
> > On Thu, Jun 14, 2018 at 4:23 PM Richard Guy Briggs <rgb@xxxxxxxxxx> 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.

> > > 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@xxxxxxxxxx>
> > > ---
> > >  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@xxxxxxxxxx>
> 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