The attached patch addresses the problem with getting the audit daemon 
shutdown credential information. It creates a new message type 
AUDIT_TERM_INFO, which is used by the audit daemon to query who issued the 
shutdown. 

It requires the placement of a hook function that gathers the information. The 
hook is after the DAC & MAC checks and before the function returns. Racing 
threads could overwrite the uid & pid - but they would have to be root and 
have policy that allows signalling the audit daemon. That should be a 
manageable risk.

The userspace component will be released later in audit 0.7.2. When it 
receives the TERM signal, it queries the kernel for shutdown information. 
When it receives it, it writes the message and exits. The message looks 
like this:

type=DAEMON msg=auditd(1114551182.000) auditd normal halt, sending pid=2650 
uid=525, auditd pid=1685

Signed-off-by: Steve Grubb <sgrubb@redhat.com>
Signed-off-by: David Woodhouse <dwmw2@infradead.org>
diff --git a/include/linux/audit.h b/include/linux/audit.h
index 19f04b0..baa8076 100644
--- a/include/linux/audit.h
+++ b/include/linux/audit.h
@@ -28,14 +28,16 @@
 #include <linux/elf.h>
 
 /* Request and reply types */
-#define AUDIT_GET      1000	/* Get status */
-#define AUDIT_SET      1001	/* Set status (enable/disable/auditd) */
-#define AUDIT_LIST     1002	/* List filtering rules */
-#define AUDIT_ADD      1003	/* Add filtering rule */
-#define AUDIT_DEL      1004	/* Delete filtering rule */
-#define AUDIT_USER     1005	/* Send a message from user-space */
-#define AUDIT_LOGIN    1006     /* Define the login id and informaiton */
-#define AUDIT_KERNEL   2000	/* Asynchronous audit record. NOT A REQUEST. */
+#define AUDIT_GET		1000	/* Get status */
+#define AUDIT_SET		1001	/* Set status (enable/disable/auditd) */
+#define AUDIT_LIST		1002	/* List filtering rules */
+#define AUDIT_ADD		1003	/* Add filtering rule */
+#define AUDIT_DEL		1004	/* Delete filtering rule */
+#define AUDIT_USER		1005	/* Send a message from user-space */
+#define AUDIT_LOGIN		1006	/* Define the login id and information */
+#define AUDIT_SIGNAL_INFO	1010	/* Get information about sender of signal*/
+
+#define AUDIT_KERNEL		2000	/* Asynchronous audit record. NOT A REQUEST. */
 
 /* Rule flags */
 #define AUDIT_PER_TASK 0x01	/* Apply rule at task creation (not syscall) */
@@ -161,6 +163,11 @@
 
 #ifdef __KERNEL__
 
+struct audit_sig_info {
+	uid_t		uid;
+	pid_t		pid;
+};
+
 struct audit_buffer;
 struct audit_context;
 struct inode;
@@ -190,6 +197,7 @@
 extern int  audit_set_loginuid(struct task_struct *task, uid_t loginuid);
 extern uid_t audit_get_loginuid(struct audit_context *ctx);
 extern int audit_ipc_perms(unsigned long qbytes, uid_t uid, gid_t gid, mode_t mode);
+extern void audit_signal_info(int sig, struct task_struct *t);
 #else
 #define audit_alloc(t) ({ 0; })
 #define audit_free(t) do { ; } while (0)
@@ -200,6 +208,7 @@
 #define audit_inode(n,i) do { ; } while (0)
 #define audit_get_loginuid(c) ({ -1; })
 #define audit_ipc_perms(q,u,g,m) ({ 0; })
+#define audit_signal_info(s,t) do { ; } while (0)
 #endif
 
 #ifdef CONFIG_AUDIT