2 files changed, 101 insertions, 3 deletions

diff --git a/src/Protocol/Protocol17x.cpp b/src/Protocol/Protocol17x.cpp
index 0d349de03..267c18a99 100644
--- a/src/Protocol/Protocol17x.cpp
+++ b/src/Protocol/Protocol17x.cpp
@@ -53,6 +53,12 @@ Implements the 1.7.x protocol classes:
 
 
 
+const int MAX_ENC_LEN = 512;  // Maximum size of the encrypted message; should be 128, but who knows...
+
+
+
+
+
 // fwd: main.cpp:
 extern bool g_ShouldLogCommIn, g_ShouldLogCommOut;
 
@@ -1351,7 +1357,64 @@ void cProtocol172::HandlePacketStatusRequest(cByteBuffer & a_ByteBuffer)
 
 void cProtocol172::HandlePacketLoginEncryptionResponse(cByteBuffer & a_ByteBuffer)
 {
-	// TODO: Add protocol encryption
+	short EncKeyLength, EncNonceLength;
+	a_ByteBuffer.ReadBEShort(EncKeyLength);
+	AString EncKey;
+	if (!a_ByteBuffer.ReadString(EncKey, EncKeyLength))
+	{
+		return;
+	}
+	a_ByteBuffer.ReadBEShort(EncNonceLength);
+	AString EncNonce;
+	if (!a_ByteBuffer.ReadString(EncNonce, EncNonceLength))
+	{
+		return;
+	}
+	if ((EncKeyLength > MAX_ENC_LEN) || (EncNonceLength > MAX_ENC_LEN))
+	{
+		LOGD("Too long encryption");
+		m_Client->Kick("Hacked client");
+		return;
+	}
+
+	// Decrypt EncNonce using privkey
+	cRSAPrivateKey & rsaDecryptor = cRoot::Get()->GetServer()->GetPrivateKey();
+	Int32 DecryptedNonce[MAX_ENC_LEN / sizeof(Int32)];
+	int res = rsaDecryptor.Decrypt((const Byte *)EncNonce.data(), EncNonce.size(), (Byte *)DecryptedNonce, sizeof(DecryptedNonce));
+	if (res != 4)
+	{
+		LOGD("Bad nonce length: got %d, exp %d", res, 4);
+		m_Client->Kick("Hacked client");
+		return;
+	}
+	if (ntohl(DecryptedNonce[0]) != (unsigned)(uintptr_t)this)
+	{
+		LOGD("Bad nonce value");
+		m_Client->Kick("Hacked client");
+		return;
+	}
+	
+	// Decrypt the symmetric encryption key using privkey:
+	Byte DecryptedKey[MAX_ENC_LEN];
+	res = rsaDecryptor.Decrypt((const Byte *)EncKey.data(), EncKey.size(), DecryptedKey, sizeof(DecryptedKey));
+	if (res != 16)
+	{
+		LOGD("Bad key length");
+		m_Client->Kick("Hacked client");
+		return;
+	}
+	
+	StartEncryption(DecryptedKey);
+
+	// Send login success:
+	{
+		cPacketizer Pkt(*this, 0x02);  // Login success packet
+		Pkt.WriteString(Printf("%d", m_Client->GetUniqueID()));  // TODO: proper UUID
+		Pkt.WriteString(m_Client->GetUsername());
+	}
+
+	m_State = 3;  // State = Game
+	m_Client->HandleLogin(4, m_Client->GetUsername());
 }
 
 
@@ -1363,14 +1426,26 @@ void cProtocol172::HandlePacketLoginStart(cByteBuffer & a_ByteBuffer)
 	AString Username;
 	a_ByteBuffer.ReadVarUTF8String(Username);
 	
-	// TODO: Protocol encryption should be set up here if not localhost / auth
-	
 	if (!m_Client->HandleHandshake(Username))
 	{
 		// The client is not welcome here, they have been sent a Kick packet already
 		return;
 	}
 	
+	// If auth is required, then send the encryption request:
+	// if (cRoot::Get()->GetServer()->ShouldAuthenticate())
+	{
+		cPacketizer Pkt(*this, 0x01);
+		Pkt.WriteString(cRoot::Get()->GetServer()->GetServerID());
+		const AString & PubKeyDer = cRoot::Get()->GetServer()->GetPublicKeyDER();
+		Pkt.WriteShort(PubKeyDer.size());
+		Pkt.WriteBuf(PubKeyDer.data(), PubKeyDer.size());
+		Pkt.WriteShort(4);
+		Pkt.WriteInt((int)(intptr_t)this);  // Using 'this' as the cryptographic nonce, so that we don't have to generate one each time :)
+		m_Client->SetUsername(Username);
+		return;
+	}
+	
 	// Send login success:
 	{
 		cPacketizer Pkt(*this, 0x02);  // Login success packet
@@ -1882,6 +1957,27 @@ void cProtocol172::ParseItemMetadata(cItem & a_Item, const AString & a_Metadata)
 
 
 
+void cProtocol172::StartEncryption(const Byte * a_Key)
+{
+	m_Encryptor.Init(a_Key, a_Key);
+	m_Decryptor.Init(a_Key, a_Key);
+	m_IsEncrypted = true;
+	
+	// Prepare the m_AuthServerID:
+	cSHA1Checksum Checksum;
+	const AString & ServerID = cRoot::Get()->GetServer()->GetServerID();
+	Checksum.Update((const Byte *)ServerID.c_str(), ServerID.length());
+	Checksum.Update(a_Key, 16);
+	Checksum.Update((const Byte *)cRoot::Get()->GetServer()->GetPublicKeyDER().data(), cRoot::Get()->GetServer()->GetPublicKeyDER().size());
+	Byte Digest[20];
+	Checksum.Finalize(Digest);
+	cSHA1Checksum::DigestToJava(Digest, m_AuthServerID);
+}
+
+
+
+
+
 ///////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
 // cProtocol172::cPacketizer:
 
diff --git a/src/Protocol/Protocol17x.h b/src/Protocol/Protocol17x.h
index 72544b575..6a75e41c8 100644
--- a/src/Protocol/Protocol17x.h
+++ b/src/Protocol/Protocol17x.h
@@ -281,6 +281,8 @@ protected:
 	
 	/// Parses item metadata as read by ReadItem(), into the item enchantments.
 	void ParseItemMetadata(cItem & a_Item, const AString & a_Metadata);
+	
+	void StartEncryption(const Byte * a_Key);
 } ;