From b283ce1e836ab08e602a11ea255ee3d8e537902e Mon Sep 17 00:00:00 2001
From: Timur Pocheptsov <timur.pocheptsov@qt.io>
Date: Thu, 10 Dec 2020 11:11:23 +0100
Subject: [PATCH] secureudpclient - a speculative fix for non-reproducible
 crash
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Not much information in a bug report: QByteArray is protected from negative
sizes and QUdpSocket too. FWIW - add one more check, similar to what
the server counterpart already had.

Pick-to: 5.15 6.0
Fixes: QTBUG-83457
Change-Id: I585fa90e0a258d2257e4fed2f24c52b47548bcbb
Reviewed-by: Mårten Nordheim <marten.nordheim@qt.io>
---
 examples/network/secureudpclient/association.cpp | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/examples/network/secureudpclient/association.cpp b/examples/network/secureudpclient/association.cpp
index c9502600789..59df94d5b91 100644
--- a/examples/network/secureudpclient/association.cpp
+++ b/examples/network/secureudpclient/association.cpp
@@ -112,6 +112,11 @@ void DtlsAssociation::udpSocketConnected()
 
 void DtlsAssociation::readyRead()
 {
+    if (socket.pendingDatagramSize() <= 0) {
+        emit warningMessage(tr("%1: spurious read notification?").arg(name));
+        return;
+    }
+
     //! [6]
     QByteArray dgram(socket.pendingDatagramSize(), Qt::Uninitialized);
     const qint64 bytesRead = socket.readDatagram(dgram.data(), dgram.size());