audit: audit feature to set loginuid immutable

This adds a new 'audit_feature' bit which allows userspace to set it
such that the loginuid is absolutely immutable, even if you have
CAP_AUDIT_CONTROL.

Signed-off-by: Eric Paris <eparis@redhat.com>
Signed-off-by: Richard Guy Briggs <rgb@redhat.com>
Signed-off-by: Eric Paris <eparis@redhat.com>
diff --git a/kernel/audit.c b/kernel/audit.c
index fbfa3a7..f3f36f5 100644
--- a/kernel/audit.c
+++ b/kernel/audit.c
@@ -144,8 +144,9 @@
 				   .features = 0,
 				   .lock = 0,};
 
-static char *audit_feature_names[1] = {
+static char *audit_feature_names[2] = {
 	"only_unset_loginuid",
+	"loginuid_immutable",
 };