From e53274c4ddd9986ca679b398d447f25a0cba889d Mon Sep 17 00:00:00 2001
From: Drew Fisher <drew.m.fisher@gmail.com>
Date: Wed, 16 Apr 2014 22:13:19 -0700
Subject: [PATCH] Parse and validate messages as JSON

Disconnect clients that send invalid frames
Log the invalid frames and the hex
---
 ribbon/ribbonserver.cpp | 13 +++++++++++--
 ribbon/ribbonsocket.cpp | 27 +++++++++++++++++----------
 ribbon/ribbonsocket.h   |  2 ++
 3 files changed, 30 insertions(+), 12 deletions(-)

diff --git a/ribbon/ribbonserver.cpp b/ribbon/ribbonserver.cpp
index 1c2ea15..1c8e3a8 100644
--- a/ribbon/ribbonserver.cpp
+++ b/ribbon/ribbonserver.cpp
@@ -3,6 +3,7 @@
 
 #include <QtNetwork/QTcpServer>
 #include <QtNetwork/QTcpSocket>
+#include <QJsonDocument>
 #include <QDebug>
 
 RibbonServer::RibbonServer(QObject* parent) :
@@ -54,6 +55,14 @@ void RibbonServer::onDisconnection(RibbonSocket* r)
 void RibbonServer::onMessageReceived(RibbonSocket* r, QByteArray buf)
 {
 	qDebug() << "server: got data from" << r->s()->peerAddress() << r->s()->peerPort();
-	qDebug() << "        message was:" << buf.constData();
-	// TODO: do something with the packet in buf.constData()
+	QJsonParseError err;
+	QJsonDocument json = QJsonDocument::fromJson(buf, &err);
+	if (json.isNull()) {
+		qWarning() << "Json did not validate:" << err.errorString();
+		qWarning() << buf.constData();
+		qWarning() << "hexencoded:" << buf.toHex().constData();
+		r->abort();
+	} else {
+		qDebug() << "json document:" << json;
+	}
 }
diff --git a/ribbon/ribbonsocket.cpp b/ribbon/ribbonsocket.cpp
index 8b7e2e5..c9c5dc9 100644
--- a/ribbon/ribbonsocket.cpp
+++ b/ribbon/ribbonsocket.cpp
@@ -1,16 +1,18 @@
 #include "ribbonsocket.h"
-#include <QDebug>
 
 RibbonSocket::RibbonSocket(QTcpSocket* sock, QObject* parent) :
 	QObject(parent),
 	socket(sock),
 	state(WANT_LENGTH),
-	bytes_wanted(0)
+	bytes_wanted(0),
+	aborting(false)
 {
 	QObject::connect(socket, SIGNAL(disconnected()),
 			this, SLOT(onDisconnect()));
 	QObject::connect(socket, SIGNAL(readyRead()),
 			this, SLOT(onReadyRead()));
+	// Take ownership of the socket
+	socket->setParent(this);
 }
 
 RibbonSocket::~RibbonSocket()
@@ -22,6 +24,12 @@ const QTcpSocket* RibbonSocket::s()
 	return socket;
 }
 
+void RibbonSocket::abort()
+{
+	aborting = true;
+	socket->abort();
+}
+
 void RibbonSocket::onDisconnect()
 {
 	emit disconnected(this);
@@ -35,7 +43,6 @@ bool RibbonSocket::tryProcess()
 {
 	switch(state) {
 		case WANT_LENGTH:
-			qDebug() << "Want length, buf size before read:" << buf.length();
 			if (readUntilBufHas(4)) {
 				// Slice 4 octets off as big-endian integer
 				QByteArray size_buf = buf.left(4);
@@ -46,19 +53,17 @@ bool RibbonSocket::tryProcess()
 				// TODO: decide on a maximum acceptable packet length, to avoid
 				// arbitrarily large packet buffer
 				buf.reserve(bytes_wanted);
-				qDebug() << "length:" << bytes_wanted;
+				qDebug() << "socket: got length:" << bytes_wanted;
 				state = WANT_DATA;
 				return true;
 			}
 			break;
 		case WANT_DATA:
-			qDebug() << "Want data, buf size before read:" << buf.length();
 			if (readUntilBufHas(bytes_wanted)) {
 				QByteArray data = buf.left(bytes_wanted);
 				buf = buf.mid(bytes_wanted);
 				// Memory optimization: release the rest of the buffer
 				buf.squeeze();
-				qDebug() << "data:" << buf;
 				emit messageReceived(this, data);
 				state = WANT_LENGTH;
 				return true;
@@ -74,10 +79,12 @@ bool RibbonSocket::tryProcess()
  */
 bool RibbonSocket::readUntilBufHas(int desired_buffer_length)
 {
-	int size_to_read = desired_buffer_length - buf.length();
-	QByteArray tmp = socket->read(size_to_read);
-	qDebug() << "read" << tmp.length() << "from socket";
-	buf += tmp;
+	// If we're shutting down the socket, don't try to read more from it
+	if (!aborting) {
+		int size_to_read = desired_buffer_length - buf.length();
+		QByteArray tmp = socket->read(size_to_read);
+		buf += tmp;
+	}
 	return buf.length() >= desired_buffer_length;
 }
 
diff --git a/ribbon/ribbonsocket.h b/ribbon/ribbonsocket.h
index e72ab6c..672c4b8 100644
--- a/ribbon/ribbonsocket.h
+++ b/ribbon/ribbonsocket.h
@@ -15,6 +15,7 @@ public:
 	RibbonSocket(QTcpSocket* socket, QObject* parent=0);
 	// Consider s to be final.  Don't modify it.
 	const QTcpSocket* s();
+	void abort();
 signals:
 	void disconnected(RibbonSocket* s);
 	void messageReceived(RibbonSocket* s, QByteArray buf);
@@ -24,6 +25,7 @@ private:
 	QByteArray buf;
 	RibbonSocketState state;
 	quint32 bytes_wanted;
+	bool aborting;
 	bool tryProcess();
 	bool readUntilBufHas(int desired_buffer_length);
 private slots:
-- 
2.39.2