[PATCH] sanity check audit_buffer

Add sanity checks for NULL audit_buffer consistent with other
audit_log* routines.

Signed-off-by: Amy Griffis <[e-mail]>
Signed-off-by: Al Viro <[e-mail]>

kernel/audit.c

···
 	struct sk_buff *skb;
 	static const unsigned char *hex = "0123456789ABCDEF";
 
+	if (!ab)
+		return;
+
 	BUG_ON(!ab->skb);
 	skb = ab->skb;
 	avail = skb_tailroom(skb);
···
 	int avail, new_len;
 	unsigned char *ptr;
 	struct sk_buff *skb;
+
+	if (!ab)
+		return;
 
 	BUG_ON(!ab->skb);
 	skb = ab->skb;