Sockets: Fix potential null pointer usages

QAbstractSocketEngine::createSocketEngine can return 0 as well as throw.
In two cases the pointer was being used before the null check, in a 3rd
case the null check was missing.

Reviewed-by: Markus Goetz
(cherry picked from commit 19edac88af53eea7f733cabbaee77f9b725b7ea9)

1 files changed, 5 insertions, 0 deletions

diff --git a/src/network/socket/qtcpserver.cpp b/src/network/socket/qtcpserver.cpp
index 5a60764a3b..026ceb4932 100644
--- a/src/network/socket/qtcpserver.cpp
+++ b/src/network/socket/qtcpserver.cpp
@@ -416,6 +416,11 @@ bool QTcpServer::setSocketDescriptor(int socketDescriptor)
     if (d->socketEngine)
         delete d->socketEngine;
     d->socketEngine = QAbstractSocketEngine::createSocketEngine(socketDescriptor, this);
+    if (!d->socketEngine) {
+        d->serverSocketError = QAbstractSocket::UnsupportedSocketOperationError;
+        d->serverSocketErrorString = tr("Operation on socket is not supported");
+        return false;
+    }
 #ifndef QT_NO_BEARERMANAGEMENT
     //copy network session down to the socket engine (if it has been set)
     d->socketEngine->setProperty("_q_networksession", property("_q_networksession"));