From 6119cb370fe410c1ef25f2d2c28c8a0edf6fac22 Mon Sep 17 00:00:00 2001
From: Chocobo1 <Chocobo1@users.noreply.github.com>
Date: Thu, 27 Jun 2019 20:29:02 +0800
Subject: [PATCH 1/2] Drop suspiciously large data

This is to avoid exhausting system memory.
---
 src/app/qtsingleapplication/qtlocalpeer.cpp | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/src/app/qtsingleapplication/qtlocalpeer.cpp b/src/app/qtsingleapplication/qtlocalpeer.cpp
index f3c4546b6..cb4c57492 100644
--- a/src/app/qtsingleapplication/qtlocalpeer.cpp
+++ b/src/app/qtsingleapplication/qtlocalpeer.cpp
@@ -191,6 +191,12 @@ void QtLocalPeer::receiveConnection()
     QByteArray uMsg;
     quint32 remaining;
     ds >> remaining;
+    if (remaining > 65535) {
+        // drop suspiciously large data
+        delete socket;
+        return;
+    }
+
     uMsg.resize(remaining);
     int got = 0;
     char* uMsgBuf = uMsg.data();

From 46ee193cd8374576abf78b68caba395794e0a9da Mon Sep 17 00:00:00 2001
From: Chocobo1 <Chocobo1@users.noreply.github.com>
Date: Thu, 27 Jun 2019 20:33:05 +0800
Subject: [PATCH 2/2] Restrict QLocalServer access

The default is world access which means even even unprivileged local
accounts can connect to it too.
---
 src/app/qtsingleapplication/qtlocalpeer.cpp | 1 +
 1 file changed, 1 insertion(+)

diff --git a/src/app/qtsingleapplication/qtlocalpeer.cpp b/src/app/qtsingleapplication/qtlocalpeer.cpp
index cb4c57492..d8a1bce31 100644
--- a/src/app/qtsingleapplication/qtlocalpeer.cpp
+++ b/src/app/qtsingleapplication/qtlocalpeer.cpp
@@ -101,6 +101,7 @@ QtLocalPeer::QtLocalPeer(QObject* parent, const QString &appId)
 #endif
 
     server = new QLocalServer(this);
+    server->setSocketOptions(QLocalServer::UserAccessOption);
     QString lockName = QDir(QDir::tempPath()).absolutePath()
                        + QLatin1Char('/') + socketName
                        + QLatin1String("-lockfile");