[PATCH] Fix AUDIT_MAC_POLICY_LOAD event formatting

[Paul Moore]

On Mon, Nov 21, 2016 at 12:30 PM, Steve Grubb <sgrubb at redhat.com> wrote:
> The AUDIT_MAC_POLICY_LOAD event has dangling text that means the same thing
> as the event type and is missing the uid and results field. The bigger issue
> is that in some failure cases no event is emitted. This patch fixes the noted
> problems.
>
> Signed-off-by: Steve Grubb <sgrubb at redhat.com>

First off, for patches such as these, I think it is good to CC the
affected subsystem, SELinux in this case (fixed).

Beyond that, I'm a little concerned that you adding fields to record
in the middle.  In the past you've warned against inserting fields in
the middle of the record, or reordering fields in general ("you'll
break the world") due to some poor userspace practices, yet you do
these exact things when it suits you.

We need a consistent message when it comes to userspace record
processing so we know what we can do in the kernel without causing
massive failure.

> --- vanilla-4.9-rc5.orig/security/selinux/selinuxfs.c   2016-11-16 15:16:34.738723900 -0500
> +++ linux-4.9.0-0.rc5.git0.1.fc24.x86_64/security/selinux/selinuxfs.c   2016-11-21 12:16:08.046787604 -0500
> @@ -494,6 +494,7 @@ static ssize_t sel_write_load(struct fil
>  {
>         ssize_t length;
>         void *data = NULL;
> +       unsigned int result = 0;
>
>         mutex_lock(&sel_mutex);
>
> @@ -525,24 +526,26 @@ static ssize_t sel_write_load(struct fil
>
>         length = sel_make_bools();
>         if (length)
> -               goto out1;
> +               goto out;
>
>         length = sel_make_classes();
>         if (length)
> -               goto out1;
> +               goto out;
>
>         length = sel_make_policycap();
>         if (length)
> -               goto out1;
> +               goto out;
>
>         length = count;
> +       result = 1;
>
> -out1:
> +out:
>         audit_log(current->audit_context, GFP_KERNEL, AUDIT_MAC_POLICY_LOAD,
> -               "policy loaded auid=%u ses=%u",
> +               "uid=%u auid=%u ses=%u res=%u",
> +               from_kuid(&init_user_ns, task_uid(current)),
>                 from_kuid(&init_user_ns, audit_get_loginuid(current)),
> -               audit_get_sessionid(current));
> -out:
> +               audit_get_sessionid(current), result);
> +
>         mutex_unlock(&sel_mutex);
>         vfree(data);
>         return length;
>
> --
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-- 
paul moore
www.paul-moore.com