From b96fdab880b6e2586404ea1c222b1a072797fc91 Mon Sep 17 00:00:00 2001
From: APTX <marek321@gmail.com>
Date: Mon, 2 Jan 2012 17:33:52 +0100
Subject: [PATCH] Make sure lib builds without encryption and that encryption
 failures result in connection errors.

---
 client.cpp | 54 +++++++++++++++++++++++++++++++++++++++++++++++++-----
 client.h   |  4 ++--
 2 files changed, 51 insertions(+), 7 deletions(-)

diff --git a/client.cpp b/client.cpp
index 778127a..d9bd5ea 100644
--- a/client.cpp
+++ b/client.cpp
@@ -547,7 +547,14 @@ qDebug() << "Entering Recieve State";
 #ifdef ANIDBUDPCLIENT_CLIENT_MISC_DEBUG
 qDebug() << "ENCRYPED DATAGRAM = " << data;
 #endif
-			tmp = decrypt(tmp);
+			// If using encryption and the reply is possibly valid before encryption, process it without decrypting.
+			// This is mainly for server errors or cases where the session (and encryption) expires.
+			// TODO Drop out of encryption if this happens?
+			if (!possiblyValid(tmp))
+				tmp = decrypt(tmp);
+
+			if (tmp.isEmpty())
+				goto endLoop;
 		}
 
 		if (authCommand.compression() && tmp.mid(0, 2) == "00")
@@ -875,13 +882,21 @@ void Client::logout(bool force)
 	enqueueControlCommand(createReply(LogoutCommand()), force);
 }
 
-#ifndef ANIDBUDPCLIENT_NO_ENCRYPT
 QByteArray Client::encrypt(const QByteArray &data)
 {
+#ifdef ANIDBUDPCLIENT_NO_ENCRYPT
+	Q_UNUSED(data);
+	m_error = EncryptionError;
+	m_errorString = tr("AniDBUDPClient built without encryption support");
+	emit connectionError();
+	return QByteArray();
+#else
 	QCA::init();
 	if (!QCA::isSupported("aes128-ecb"))
 	{
-		qDebug() << "encryption failed due to no aes128-cbc";
+		m_error = EncryptionError;
+		m_errorString = tr("QCA missing required encryption plugins");
+		emit connectionError();
 		return QByteArray();
 	}
 
@@ -904,14 +919,19 @@ qDebug() << "PADDED DATA\n\t" << paddedData << "\n\t" << paddedData.toHex();
 	c.final(); // Should be empty as data is already padded
 //	QCA::deinit();
 	return ret;
+#endif
 }
 
 QByteArray Client::decrypt(const QByteArray &data)
 {
+#ifdef ANIDBUDPCLIENT_NO_ENCRYPT
+	Q_UNUSED(data);
+	return QByteArray();
+#else
 	QCA::init();
 	if (!QCA::isSupported("aes128-ecb"))
 	{
-		qDebug() << "encryption failed due to no aes128-cbc";
+		qDebug() << "decryption failed due to no aes128-cbc";
 		return QByteArray();
 	}
 
@@ -933,6 +953,15 @@ qDebug() << "PART 2 = " << p2;
 #endif
 	ret += p2;
 
+	if (ret.size() % 16 != 0)
+	{
+		// Should be a multiple of cipher block size.
+#ifdef ANIDBUDPCLIENT_CLIENT_ENCRYPT_DEBUG
+qDebug() << "Ciphertext not a multiple of cipher block size!!";
+#endif
+		return QByteArray();
+	}
+
 	// Remove padding (and only it)
 	char pad = ret[ret.size() - 1];
 	if (pad > 0 && pad < 16)
@@ -954,8 +983,21 @@ qDebug() << "PART 2 = " << p2;
 	}
 //	QCA::deinit();
 	return ret;
-}
 #endif
+}
+
+bool Client::possiblyValid(const QByteArray &reply) const
+{
+	QByteArray tag = reply.left(5);
+	if (sentCommands.contains(tag))
+		return true;
+	bool ok;
+	tag = reply.left(3);
+	tag.toInt(&ok);
+	if (ok)
+		return true;
+	return false;
+}
 
 void Client::commandTimeout()
 {
@@ -1088,6 +1130,8 @@ qDebug() << QString("SENDING datagram:\n\t%1\nto: %2 ([%3]:%4) (%5 encryption)")
 qDebug() << QString("ENCRYPTED datagram:\n\t%1")
 		.arg(datagram.constData());
 #endif
+		if (datagram.isEmpty())
+			return;
 	}
 
 	socket->writeDatagram(datagram, m_hostAddress, m_hostPort);
diff --git a/client.h b/client.h
index 17d9b56..5cabdb5 100644
--- a/client.h
+++ b/client.h
@@ -164,10 +164,10 @@ private:
 
 	void logout(bool force);
 
-#ifndef ANIDBUDPCLIENT_NO_ENCRYPT
 	QByteArray encrypt(const QByteArray &data);
 	QByteArray decrypt(const QByteArray &data);
-#endif
+
+	bool possiblyValid(const QByteArray &reply) const;
 
 	QTimer *commandTimer;
 	QTimer *idleTimer;
-- 
2.52.0