Re: [PATCH ghak90 V8 05/16] audit: log drop of contid on exit of last task

[Paul Moore <paul@xxxxxxxxxxxxxx>]

On Tue, Dec 31, 2019 at 2:50 PM Richard Guy Briggs <rgb@xxxxxxxxxx> wrote:
>
> Since we are tracking the life of each audit container indentifier, we
> can match the creation event with the destruction event.  Log the
> destruction of the audit container identifier when the last process in
> that container exits.
>
> Signed-off-by: Richard Guy Briggs <rgb@xxxxxxxxxx>
> ---
>  kernel/audit.c   | 17 +++++++++++++++++
>  kernel/audit.h   |  2 ++
>  kernel/auditsc.c |  2 ++
>  3 files changed, 21 insertions(+)
>
> diff --git a/kernel/audit.c b/kernel/audit.c
> index 4bab20f5f781..fa8f1aa3a605 100644
> --- a/kernel/audit.c
> +++ b/kernel/audit.c
> @@ -2502,6 +2502,23 @@ int audit_set_contid(struct task_struct *task, u64 contid)
>         return rc;
>  }
>
> +void audit_log_container_drop(void)
> +{
> +       struct audit_buffer *ab;
> +
> +       if (!current->audit || !current->audit->cont ||
> +           refcount_read(&current->audit->cont->refcount) > 1)
> +               return;
> +       ab = audit_log_start(audit_context(), GFP_KERNEL, AUDIT_CONTAINER_OP);
> +       if (!ab)
> +               return;
> +
> +       audit_log_format(ab, "op=drop opid=%d contid=%llu old-contid=%llu",
> +                        task_tgid_nr(current), audit_get_contid(current),
> +                        audit_get_contid(current));
> +       audit_log_end(ab);
> +}

Assumine we are careful about where we call it in audit_free(...), you
are confident we can't do this as part of _audit_contobj_put(...),
yes?


>  /**
>   * audit_log_end - end one audit record
>   * @ab: the audit_buffer
> diff --git a/kernel/audit.h b/kernel/audit.h
> index e4a31aa92dfe..162de8366b32 100644
> --- a/kernel/audit.h
> +++ b/kernel/audit.h
> @@ -255,6 +255,8 @@ extern void audit_log_d_path_exe(struct audit_buffer *ab,
>  extern struct tty_struct *audit_get_tty(void);
>  extern void audit_put_tty(struct tty_struct *tty);
>
> +extern void audit_log_container_drop(void);
> +
>  /* audit watch/mark/tree functions */
>  #ifdef CONFIG_AUDITSYSCALL
>  extern unsigned int audit_serial(void);
> diff --git a/kernel/auditsc.c b/kernel/auditsc.c
> index 0e2d50533959..bd855794ad26 100644
> --- a/kernel/auditsc.c
> +++ b/kernel/auditsc.c
> @@ -1568,6 +1568,8 @@ static void audit_log_exit(void)
>
>         audit_log_proctitle();
>
> +       audit_log_container_drop();
> +
>         /* Send end of event record to help user space know we are finished */
>         ab = audit_log_start(context, GFP_KERNEL, AUDIT_EOE);
>         if (ab)
> --
> 1.8.3.1
>

--
paul moore
www.paul-moore.com