veyron/services/mgmt/node: Initial implementation of device claim in the NodeManager

Change-Id: I89b6689cccebc3e3256999027d804a4ccc058a58
diff --git a/security/util.go b/security/util.go
index 541aa90..b709c31 100644
--- a/security/util.go
+++ b/security/util.go
@@ -11,6 +11,13 @@
 
 var nullACL security.ACL
 
+// OpenACL creates an ACL that grants access to all principals.
+func OpenACL() security.ACL {
+	acl := security.ACL{}
+	acl.In = map[security.BlessingPattern]security.LabelSet{security.AllPrincipals: security.AllLabels}
+	return acl
+}
+
 // LoadIdentity reads a PrivateID from r, assuming that it was written using
 // SaveIdentity.
 func LoadIdentity(r io.Reader) (security.PrivateID, error) {