[PATCH 1/2] fix audit skb leak on congested netlink socket

[PATCH 1/2] fix audit skb leak on congested netlink socket

[Chris Wright]

When auditd is congested the kernel's audit system leaks skb's.  First,
it takes them off the audit_buffer sklist at which point they are lost,
second, it allocates a new skb with 0 length payload.  Then (likely still
congested), it repeats this losing the new skb.  Plug the leak by making
sure to requeue the skb, and avoid audit_log_move() on 0 len audit_buffer.

Signed-off-by: Chris Wright <chrisw@osdl.org>

===== kernel/audit.c 1.6 vs edited =====
--- 1.6/kernel/audit.c	2005-01-20 20:56:04 -08:00
+++ edited/kernel/audit.c	2005-01-25 14:34:32 -08:00
@@ -494,6 +494,10 @@ static void audit_log_move(struct audit_
 	char		*start;
 	int		extra = ab->nlh ? 0 : NLMSG_SPACE(0);
 
+	/* possible resubmission */
+	if (ab->len == 0)
+		return;
+
 	skb = skb_peek(&ab->sklist);
 	if (!skb || skb_tailroom(skb) <= ab->len + extra) {
 		skb = alloc_skb(2 * ab->len + extra, GFP_ATOMIC);
@@ -535,6 +539,7 @@ static inline int audit_log_drain(struct
 		}
 		if (retval == -EAGAIN && ab->count < 5) {
 			++ab->count;
+			skb_queue_tail(&ab->sklist, skb);
 			audit_log_end_irq(ab);
 			return 1;
 		}

[PATCH 2/2] some minor cleanups for audit_log_lost() messages

[Chris Wright]

Some minor cleanups for audit_log_lost() messages.

Signed-off-by: Chris Wright <chrisw@osdl.org>

===== kernel/audit.c 1.7 vs edited =====
--- 1.7/kernel/audit.c	2005-01-25 14:35:07 -08:00
+++ edited/kernel/audit.c	2005-01-25 14:35:54 -08:00
@@ -160,7 +160,7 @@ static void audit_panic(const char *mess
 		printk(KERN_ERR "audit: %s\n", message);
 		break;
 	case AUDIT_FAIL_PANIC:
-		panic(message);
+		panic("audit: %s\n", message);
 		break;
 	}
 }
@@ -663,10 +663,10 @@ struct audit_buffer *audit_log_start(str
 
 	if (!ab)
 		ab = kmalloc(sizeof(*ab), GFP_ATOMIC);
-	if (!ab)
-		audit_log_lost("audit: out of memory in audit_log_start");
-	if (!ab)
+	if (!ab) {
+		audit_log_lost("out of memory in audit_log_start");
 		return NULL;
+	}
 
 	atomic_inc(&audit_backlog);
 	skb_queue_head_init(&ab->sklist);