On 2020-01-22 16:28, Paul Moore wrote:

On Tue, Dec 31, 2019 at 2:50 PM Richard Guy Briggs [off-list ref] wrote:

quoted

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 <redacted>
---
 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?

We need audit_log_container_drop in audit_free_syscall() due to needing
context, which gets freed in audit_free_syscall() called from
audit_free().

We need audit_log_container_drop in audit_log_exit() due to having that
record included before the EOE record at the end of audit_log_exit().

We could put in _contobj_put() if we drop context and any attempt to
connect it with a syscall record, which I strongly discourage.

The syscall record contains info about subject, container_id record only
contains info about container object other than subj pid.

quoted

 /**
  * 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

- RGB

--
Richard Guy Briggs [off-list ref]
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