From 7f4d3e3d7b3f4b1557f9f2848081db2b898d2055 Mon Sep 17 00:00:00 2001
From: Nicolas Tsiftes <nvt@sics.se>
Date: Thu, 27 Mar 2014 15:55:38 +0100
Subject: [PATCH] Avoid calling rpl_lock_parent for uninitialized memory.
 Renamed p to parent to make reading easier.

---
 core/net/rpl/rpl-icmp6.c | 23 ++++++++++++-----------
 1 file changed, 12 insertions(+), 11 deletions(-)

diff --git a/core/net/rpl/rpl-icmp6.c b/core/net/rpl/rpl-icmp6.c
index c1cc6060b..d1ff56837 100644
--- a/core/net/rpl/rpl-icmp6.c
+++ b/core/net/rpl/rpl-icmp6.c
@@ -583,10 +583,11 @@ dao_input(void)
   int len;
   int i;
   int learned_from;
-  rpl_parent_t *p;
+  rpl_parent_t *parent;
   uip_ds6_nbr_t *nbr;
 
   prefixlen = 0;
+  parent = NULL;
 
   uip_ipaddr_copy(&dao_sender_addr, &UIP_IP_BUF->srcipaddr);
 
@@ -634,23 +635,23 @@ dao_input(void)
          learned_from == RPL_ROUTE_FROM_UNICAST_DAO? "unicast": "multicast");
   if(learned_from == RPL_ROUTE_FROM_UNICAST_DAO) {
     /* Check whether this is a DAO forwarding loop. */
-    p = rpl_find_parent(dag, &dao_sender_addr);
+    parent = rpl_find_parent(dag, &dao_sender_addr);
     /* check if this is a new DAO registration with an "illegal" rank */
     /* if we already route to this node it is likely */
-    if(p != NULL &&
-       DAG_RANK(p->rank, instance) < DAG_RANK(dag->rank, instance)) {
+    if(parent != NULL &&
+       DAG_RANK(parent->rank, instance) < DAG_RANK(dag->rank, instance)) {
       PRINTF("RPL: Loop detected when receiving a unicast DAO from a node with a lower rank! (%u < %u)\n",
-          DAG_RANK(p->rank, instance), DAG_RANK(dag->rank, instance));
-      p->rank = INFINITE_RANK;
-      p->updated = 1;
+          DAG_RANK(parent->rank, instance), DAG_RANK(dag->rank, instance));
+      parent->rank = INFINITE_RANK;
+      parent->updated = 1;
       return;
     }
 
     /* If we get the DAO from our parent, we also have a loop. */
-    if(p != NULL && p == dag->preferred_parent) {
+    if(parent != NULL && parent == dag->preferred_parent) {
       PRINTF("RPL: Loop detected when receiving a unicast DAO from our parent\n");
-      p->rank = INFINITE_RANK;
-      p->updated = 1;
+      parent->rank = INFINITE_RANK;
+      parent->updated = 1;
       return;
     }
   }
@@ -756,7 +757,7 @@ dao_input(void)
     PRINTF("RPL: Neighbor already in neighbor cache\n");
   }
 
-  rpl_lock_parent(p);
+  rpl_lock_parent(parent);
 
   rep = rpl_add_route(dag, &prefix, prefixlen, &dao_sender_addr);
   if(rep == NULL) {