diff --git a/apps/aaa/src/main/java/org/onosproject/aaa/AaaManager.java b/apps/aaa/src/main/java/org/onosproject/aaa/AaaManager.java
old mode 100644
new mode 100755
index 30ef879..0339a7e
--- a/apps/aaa/src/main/java/org/onosproject/aaa/AaaManager.java
+++ b/apps/aaa/src/main/java/org/onosproject/aaa/AaaManager.java
@@ -349,6 +349,16 @@
                     sendPacketToSupplicant(eth, stateMachine.supplicantConnectpoint());
 
                     break;
+                case EAPOL.EAPOL_LOGOFF:
+                    if (stateMachine.state() == stateMachine.STATE_AUTHORIZED) {
+                        try {
+                            stateMachine.logoff();
+                        } catch (StateMachineException e) {
+                            e.printStackTrace();
+                        }
+                    }
+
+                    break;
                 case EAPOL.EAPOL_PACKET:
                     RADIUS radiusPayload;
                     // check if this is a Response/Identify or  a Response/TLS
@@ -380,8 +390,10 @@
                                                          stateMachine.identifier(),
                                                          eapPacket);
 
-                                radiusPayload.setAttribute(RADIUSAttribute.RADIUS_ATTR_STATE,
-                                                           stateMachine.challengeState());
+                                if (stateMachine.challengeState() != null) {
+                                    radiusPayload.setAttribute(RADIUSAttribute.RADIUS_ATTR_STATE,
+                                            stateMachine.challengeState());
+                                }
                                 radiusPayload.addMessageAuthenticator(AaaManager.this.radiusSecret);
                                 sendRadiusPacket(radiusPayload);
                             }
@@ -390,8 +402,10 @@
                             // request id access to RADIUS
                             radiusPayload = getRadiusPayload(stateMachine, stateMachine.identifier(), eapPacket);
 
-                            radiusPayload.setAttribute(RADIUSAttribute.RADIUS_ATTR_STATE,
-                                    stateMachine.challengeState());
+                            if (stateMachine.challengeState() != null) {
+                                radiusPayload.setAttribute(RADIUSAttribute.RADIUS_ATTR_STATE,
+                                        stateMachine.challengeState());
+                            }
                             stateMachine.setRequestAuthenticator(radiusPayload.generateAuthCode());
 
                             radiusPayload.addMessageAuthenticator(AaaManager.this.radiusSecret);
@@ -432,8 +446,11 @@
             Ethernet eth;
             switch (radiusPacket.getCode()) {
                 case RADIUS.RADIUS_CODE_ACCESS_CHALLENGE:
-                    byte[] challengeState =
-                            radiusPacket.getAttribute(RADIUSAttribute.RADIUS_ATTR_STATE).getValue();
+                    RADIUSAttribute radiusAttrState = radiusPacket.getAttribute(RADIUSAttribute.RADIUS_ATTR_STATE);
+                    byte[] challengeState = null;
+                    if (radiusAttrState != null) {
+                        challengeState = radiusAttrState.getValue();
+                    }
                     eapPayload = radiusPacket.decapsulateMessage();
                     stateMachine.setChallengeInfo(eapPayload.getIdentifier(), challengeState);
                     eth = buildEapolResponse(stateMachine.supplicantAddress(),
diff --git a/utils/misc/src/main/java/org/onlab/packet/RADIUS.java b/utils/misc/src/main/java/org/onlab/packet/RADIUS.java
index de0cb39..0a2b220 100644
--- a/utils/misc/src/main/java/org/onlab/packet/RADIUS.java
+++ b/utils/misc/src/main/java/org/onlab/packet/RADIUS.java
@@ -373,7 +373,7 @@
                 attr.value = new byte[attrLength - 2];
                 bb.get(attr.value, 0, attrLength - 2);
                 radius.attributes.add(attr);
-                remainingLength -= attr.length;
+                remainingLength -= attrLength;
             }
             return radius;
         };