From 95543d8747cbf7c1945ac36c36031ae40152cf2f Mon Sep 17 00:00:00 2001
From: practicalswift <practicalswift@users.noreply.github.com>
Date: Tue, 28 Feb 2017 15:49:49 +0100
Subject: [PATCH] [net] Avoid possibility of NULL pointer dereference in
 MarkBlockAsInFlight(...)

In the case that the branch ...

    if (itInFlight != mapBlocksInFlight.end() && itInFlight->second.first == nodeid) {

... is taken, there was prior to this commit an implicit assumption that
MarkBlockAsInFlight(...) was being called with its fifth and optional
argument (pit) being present (and non-NULL).
---
 src/net_processing.cpp | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/src/net_processing.cpp b/src/net_processing.cpp
index 72c403a57..521dd02ab 100644
--- a/src/net_processing.cpp
+++ b/src/net_processing.cpp
@@ -338,7 +338,9 @@ bool MarkBlockAsInFlight(NodeId nodeid, const uint256& hash, const Consensus::Pa
     // Short-circuit most stuff in case its from the same node
     map<uint256, pair<NodeId, list<QueuedBlock>::iterator> >::iterator itInFlight = mapBlocksInFlight.find(hash);
     if (itInFlight != mapBlocksInFlight.end() && itInFlight->second.first == nodeid) {
-        *pit = &itInFlight->second.second;
+        if (pit) {
+            *pit = &itInFlight->second.second;
+        }
         return false;
     }