close #34 close #33 close #31, add option to allow local addresses and an option to require hostname

README.md

@@ -1,7 +1,7 @@
 VIAaaS
 ---
-Idea: server.example.com._p25565._v1_12_2._otrue._uBACKUSERNAME.viaaas.example.com (default backend 25565 port and version
- default as auto, online-mode can be optional/required) (similar to tor to web proxies)
+How to use: server.example.com._p25565._v1_12_2._uBACKUSERNAME.viaaas.example.com (similar to tor to web proxies)
+Default WS URL: wss://localhost:25543/ws
 
 - TODO: _o option for disabling online mode only in front end, protocol auto detection
 
@@ -28,9 +28,9 @@ Usage for online mode (may block your Mojang account):
  https://www.curseforge.com/minecraft/mc-mods/auth-me for reauthenticate the client.)
 - You should set up a CORS Proxy (something like https://github.com/Rob--W/cors-anywhere) on local machine.
 - Go to https://localhost:25543/auth.html, configure the CORS Proxy URL (something like http://localhost:8080/) and listen to
- the username you're using to connect.
-- Add web page the account you used in _u parameter.
-- Connect to mc.example.com._v1_8.viaaas._u(BACKUSERNAME).localhost
+ the username A that you're using to connect to the proxy.
+- Add web page the account B you used in _u parameter.
+- Connect to mc.example.com._v1_8.viaaas._u(account B).localhost
 - Approve the login
 - There are some information about Mojang password resetting: https://github.com/GeyserMC/Geyser/wiki/Common-Issues#mojang-resetting-account-credentials and https://mobile.twitter.com/MojangSupport/status/863697596350517248
 

src/main/kotlin/com/github/creeper123123321/viaaas/CloudCodec.kt

@@ -1,7 +1,6 @@
 package com.github.creeper123123321.viaaas
 
 import io.netty.buffer.ByteBuf
-import io.netty.buffer.Unpooled
 import io.netty.channel.Channel
 import io.netty.channel.ChannelHandlerContext
 import io.netty.channel.ChannelInitializer
@@ -25,12 +24,12 @@ object ChannelInit : ChannelInitializer<Channel>() {
         val user = UserConnection(ch)
         CloudPipeline(user)
         ch.pipeline().addLast("timeout", ReadTimeoutHandler(30, TimeUnit.SECONDS))
-                // "crypto"
-                .addLast("frame", FrameCodec())
-                // "compress" / dummy "decompress"
-                .addLast("flow-handler", FlowControlHandler())
-                .addLast("via-codec", CloudViaCodec(user))
-                .addLast("handler", CloudMinecraftHandler(user, null, frontEnd = true))
+            // "crypto"
+            .addLast("frame", FrameCodec())
+            // "compress" / dummy "decompress"
+            .addLast("flow-handler", FlowControlHandler())
+            .addLast("via-codec", CloudViaCodec(user))
+            .addLast("handler", CloudMinecraftHandler(user, null, frontEnd = true))
     }
 }
 
@@ -53,22 +52,23 @@ class CloudCrypto(val cipherDecode: Cipher, var cipherEncode: Cipher) : MessageT
 class BackendInit(val user: UserConnection) : ChannelInitializer<Channel>() {
     override fun initChannel(ch: Channel) {
         ch.pipeline().addLast("timeout", ReadTimeoutHandler(30, TimeUnit.SECONDS))
-                // "crypto"
-                .addLast("frame", FrameCodec())
-                // compress
-                .addLast("handler", CloudMinecraftHandler(user, null, frontEnd = false))
+            // "crypto"
+            .addLast("frame", FrameCodec())
+            // compress
+            .addLast("handler", CloudMinecraftHandler(user, null, frontEnd = false))
     }
 }
 
 class CloudCompressionCodec(val threshold: Int) : MessageToMessageCodec<ByteBuf, ByteBuf>() {
     // https://github.com/Gerrygames/ClientViaVersion/blob/master/src/main/java/de/gerrygames/the5zig/clientviaversion/netty/CompressionEncoder.java
-    private val inflater: Inflater = Inflater()// https://github.com/Gerrygames/ClientViaVersion/blob/master/src/main/java/de/gerrygames/the5zig/clientviaversion/netty/CompressionEncoder.java
+    private val inflater: Inflater =
+        Inflater()// https://github.com/Gerrygames/ClientViaVersion/blob/master/src/main/java/de/gerrygames/the5zig/clientviaversion/netty/CompressionEncoder.java
     private val deflater: Deflater = Deflater()
 
     @Throws(Exception::class)
     override fun encode(ctx: ChannelHandlerContext, input: ByteBuf, out: MutableList<Any>) {
         val frameLength = input.readableBytes()
-        val outBuf = ctx.alloc().heapBuffer()
+        val outBuf = ctx.alloc().buffer()
         try {
             if (frameLength < threshold) {
                 outBuf.writeByte(0)
@@ -77,15 +77,12 @@ class CloudCompressionCodec(val threshold: Int) : MessageToMessageCodec<ByteBuf,
                 return
             }
             Type.VAR_INT.writePrimitive(outBuf, frameLength)
-            val inBytes = ByteArray(frameLength)
-            input.readBytes(inBytes)
-            deflater.setInput(inBytes, 0, frameLength)
+            deflater.setInput(input.nioBuffer())
             deflater.finish()
             while (!deflater.finished()) {
                 outBuf.ensureWritable(8192)
                 val wIndex = outBuf.writerIndex()
-                outBuf.writerIndex(wIndex + deflater.deflate(outBuf.array(),
-                        outBuf.arrayOffset() + wIndex, outBuf.writableBytes()))
+                outBuf.writerIndex(wIndex + deflater.deflate(outBuf.nioBuffer(wIndex, outBuf.writableBytes())))
             }
             out.add(outBuf.retain())
         } finally {
@@ -110,13 +107,16 @@ class CloudCompressionCodec(val threshold: Int) : MessageToMessageCodec<ByteBuf,
                 throw DecoderException("Badly compressed packet - size of $outLength is larger than protocol maximum of 2097152")
             }
 
-            val temp = ByteArray(input.readableBytes())
-            input.readBytes(temp)
-            inflater.setInput(temp)
-            val output = ByteArray(outLength)
-            inflater.inflate(output)
-            out.add(Unpooled.wrappedBuffer(output))
-            inflater.reset()
+            inflater.setInput(input.nioBuffer())
+            val output = ctx.alloc().buffer(outLength, outLength)
+            try {
+                output.writerIndex(output.writerIndex() + inflater.inflate(
+                        output.nioBuffer(output.writerIndex(), output.writableBytes())))
+                out.add(output.retain())
+            } finally {
+                inflater.reset()
+                output.release()
+            }
         }
     }
 

src/main/kotlin/com/github/creeper123123321/viaaas/CloudHandler.kt

@@ -19,15 +19,17 @@ import kotlinx.coroutines.launch
 import org.slf4j.LoggerFactory
 import us.myles.ViaVersion.api.data.StoredObject
 import us.myles.ViaVersion.api.data.UserConnection
+import us.myles.ViaVersion.api.protocol.ProtocolVersion
 import us.myles.ViaVersion.api.type.Type
 import us.myles.ViaVersion.exception.CancelCodecException
+import us.myles.ViaVersion.packets.State
+import java.math.BigInteger
 import java.net.InetAddress
 import java.net.InetSocketAddress
 import java.net.SocketAddress
-import java.security.KeyFactory
+import java.security.MessageDigest
 import java.security.PrivateKey
 import java.security.PublicKey
-import java.security.spec.X509EncodedKeySpec
 import java.util.*
 import javax.crypto.Cipher
 import javax.crypto.spec.IvParameterSpec
@@ -37,27 +39,30 @@ import javax.naming.directory.InitialDirContext
 
 val chLogger = LoggerFactory.getLogger("VIAaaS MC Handler")
 
-class HandlerData(userConnection: UserConnection,
-                  var state: MinecraftConnectionState,
-                  var protocolId: Int? = null,
-                  var frontName: String? = null,
-                  var backName: String? = null,
-                  var backServerId: String? = null,
-                  var backPublicKey: PublicKey? = null,
-                  var backToken: ByteArray? = null,
-                  var frontToken: ByteArray? = null,
-                  var frontId: String? = null
+class HandlerData(
+    userConnection: UserConnection,
+    var state: MinecraftConnectionState,
+    var protocolId: Int? = null,
+    var frontName: String? = null,
+    var backName: String? = null,
+    var backServerId: String? = null,
+    var backPublicKey: PublicKey? = null,
+    var backToken: ByteArray? = null,
+    var frontToken: ByteArray? = null,
+    var frontId: String? = null
 ) : StoredObject(userConnection)
 
-class CloudMinecraftHandler(val user: UserConnection,
-                            var other: Channel?,
-                            val frontEnd: Boolean) : SimpleChannelInboundHandler<ByteBuf>() {
-    val data get() = user.get(HandlerData::class.java)
+class CloudMinecraftHandler(
+    val user: UserConnection,
+    var other: Channel?,
+    val frontEnd: Boolean
+) : SimpleChannelInboundHandler<ByteBuf>() {
+    val data get() = user.get(HandlerData::class.java)!!
     var address: SocketAddress? = null
 
     override fun channelRead0(ctx: ChannelHandlerContext, msg: ByteBuf) {
         if (ctx.channel().isActive && !user.isPendingDisconnect && msg.isReadable) {
-            data!!.state.handleMessage(this, ctx, msg)
+            data.state.handleMessage(this, ctx, msg)
             if (msg.isReadable) throw IllegalStateException("Remaining bytes!!!")
             //other?.write(msg.retain())
         }
@@ -65,14 +70,14 @@ class CloudMinecraftHandler(val user: UserConnection,
 
     override fun channelActive(ctx: ChannelHandlerContext) {
         address = ctx.channel().remoteAddress()
-        if (data == null) {
+        if (user.get(HandlerData::class.java) == null) {
             user.put(HandlerData(user, HandshakeState()))
         }
     }
 
     override fun channelInactive(ctx: ChannelHandlerContext) {
         other?.close()
-        data!!.state.onInactivated(this)
+        data.state.onInactivated(this)
     }
 
     override fun channelReadComplete(ctx: ChannelHandlerContext?) {
@@ -90,13 +95,15 @@ class CloudMinecraftHandler(val user: UserConnection,
     }
 
     fun disconnect(s: String) {
-        data!!.state.disconnect(this, s)
+        data.state.disconnect(this, s)
     }
 }
 
 interface MinecraftConnectionState {
-    fun handleMessage(handler: CloudMinecraftHandler, ctx: ChannelHandlerContext,
-                      msg: ByteBuf)
+    fun handleMessage(
+        handler: CloudMinecraftHandler, ctx: ChannelHandlerContext,
+        msg: ByteBuf
+    )
 
     fun disconnect(handler: CloudMinecraftHandler, msg: String) {
         chLogger.info("Disconnected ${handler.address}: $msg")
@@ -110,14 +117,17 @@ interface MinecraftConnectionState {
 
 class HandshakeState : MinecraftConnectionState {
     override fun handleMessage(handler: CloudMinecraftHandler, ctx: ChannelHandlerContext, msg: ByteBuf) {
-        if (!handler.frontEnd || Type.VAR_INT.readPrimitive(msg) != 0) throw IllegalArgumentException("Invalid packet ID!")
-        handler.data!!.protocolId = Type.VAR_INT.readPrimitive(msg)
-        val backAddr = Type.STRING.read(msg)
-        val backPort = Type.UNSIGNED_SHORT.read(msg)
-        val nextAddr = Type.VAR_INT.readPrimitive(msg)
-        when (nextAddr) {
-            1 -> handler.data!!.state = StatusState
-            2 -> handler.data!!.state = LoginState
+        val packet = PacketRegistry.decode(
+            msg,
+            ProtocolVersion.getProtocol(handler.user.protocolInfo!!.serverProtocolVersion),
+            State.HANDSHAKE,
+            handler.frontEnd
+        )
+        if (packet !is HandshakePacket) throw IllegalArgumentException("Invalid packet!")
+        handler.data.protocolId = packet.protocolId
+        when (packet.nextState.ordinal) {
+            1 -> handler.data.state = StatusState
+            2 -> handler.data.state = LoginState
             else -> throw IllegalStateException("Invalid next state")
         }
 
@@ -125,13 +135,13 @@ class HandshakeState : MinecraftConnectionState {
         GlobalScope.launch(Dispatchers.IO) {
             val frontHandler = handler.user.channel!!.pipeline().get(CloudMinecraftHandler::class.java)
             try {
-                var srvResolvedAddr = backAddr
-                var srvResolvedPort = backPort
+                var srvResolvedAddr = packet.address
+                var srvResolvedPort = packet.port
                 if (srvResolvedPort == 25565) {
                     try {
                         // https://github.com/GeyserMC/Geyser/blob/99e72f35b308542cf0dbfb5b58816503c3d6a129/connector/src/main/java/org/geysermc/connector/GeyserConnector.java
                         val attr = InitialDirContext()
-                                .getAttributes("dns:///_minecraft._tcp.$backAddr", arrayOf("SRV"))["SRV"]
+                            .getAttributes("dns:///_minecraft._tcp.$srvResolvedAddr", arrayOf("SRV"))["SRV"]
                         if (attr != null && attr.size() > 0) {
                             val record = (attr.get(0) as String).split(" ")
                             srvResolvedAddr = record[3]
@@ -142,16 +152,17 @@ class HandshakeState : MinecraftConnectionState {
                 }
                 val socketAddr = InetSocketAddress(InetAddress.getByName(srvResolvedAddr), srvResolvedPort)
                 val addrInfo = socketAddr.address
-                if (addrInfo.isSiteLocalAddress
-                        || addrInfo.isLoopbackAddress
-                        || addrInfo.isLinkLocalAddress
-                        || addrInfo.isAnyLocalAddress) throw SecurityException("Local addresses aren't allowed")
+                if (VIAaaSConfig.blockLocalAddress && (addrInfo.isSiteLocalAddress
+                    || addrInfo.isLoopbackAddress
+                    || addrInfo.isLinkLocalAddress
+                    || addrInfo.isAnyLocalAddress)
+                ) throw SecurityException("Local addresses aren't allowed")
 
                 val bootstrap = Bootstrap().handler(BackendInit(handler.user))
-                        .channelFactory(channelSocketFactory())
-                        .group(handler.user.channel!!.eventLoop())
-                        .option(ChannelOption.CONNECT_TIMEOUT_MILLIS, 15_000) // Half of mc timeout
-                        .connect(socketAddr)
+                    .channelFactory(channelSocketFactory())
+                    .group(handler.user.channel!!.eventLoop())
+                    .option(ChannelOption.CONNECT_TIMEOUT_MILLIS, 15_000) // Half of mc timeout
+                    .connect(socketAddr)
 
                 bootstrap.addListener {
                     if (it.isSuccess) {
@@ -161,23 +172,15 @@ class HandshakeState : MinecraftConnectionState {
                         backChan.pipeline().get(CloudMinecraftHandler::class.java).other = handler.user.channel
                         frontHandler.other = backChan
 
-                        val backHandshake = ByteBufAllocator.DEFAULT.buffer()
-                        try {
-                            backHandshake.writeByte(0) // Packet 0 handshake
-                            Type.VAR_INT.writePrimitive(backHandshake, handler.data!!.protocolId!!)
-                            Type.STRING.write(backHandshake, srvResolvedAddr) // Server Address
-                            backHandshake.writeShort(srvResolvedPort)
-                            Type.VAR_INT.writePrimitive(backHandshake, nextAddr)
-                            backChan.writeAndFlush(backHandshake.retain())
-                        } finally {
-                            backHandshake.release()
-                        }
+                        packet.address = srvResolvedAddr
+                        packet.port = srvResolvedPort
+                        forward(handler, packet)
+                        backChan.flush()
 
                         handler.user.channel!!.setAutoRead(true)
                     } else {
-                        handler.user.channel!!.eventLoop().submit {
-                            frontHandler.disconnect("Couldn't connect: " + it.cause().toString())
-                        }
+                        // We're in the event loop
+                        frontHandler.disconnect("Couldn't connect: " + it.cause().toString())
                     }
                 }
             } catch (e: Exception) {
@@ -199,50 +202,49 @@ class HandshakeState : MinecraftConnectionState {
 
 object LoginState : MinecraftConnectionState {
     override fun handleMessage(handler: CloudMinecraftHandler, ctx: ChannelHandlerContext, msg: ByteBuf) {
-        msg.markReaderIndex()
-        val id = Type.VAR_INT.readPrimitive(msg)
-        when {
-            handler.frontEnd && id == 0 -> handleLoginStart(handler, msg)
-            handler.frontEnd && id == 1 -> handleCryptoResponse(handler, msg)
-            handler.frontEnd && id == 2 -> forward(handler, msg) // Plugin response
-            !handler.frontEnd && id == 0 -> forward(handler, msg) // Disconnect
-            !handler.frontEnd && id == 1 -> handleCryptoRequest(handler, msg)
-            !handler.frontEnd && id == 2 -> handleLoginSuccess(handler, msg)
-            !handler.frontEnd && id == 3 -> handleCompression(handler, msg)
-            !handler.frontEnd && id == 4 -> forward(handler, msg) // Plugin request
-            else -> throw IllegalArgumentException("Invalid packet ID")
+        val packet = PacketRegistry.decode(
+            msg,
+            ProtocolVersion.getProtocol(handler.user.protocolInfo!!.serverProtocolVersion),
+            State.LOGIN,
+            handler.frontEnd
+        )
+
+        when (packet) {
+            is LoginStart -> handleLoginStart(handler, packet)
+            is CryptoResponse -> handleCryptoResponse(handler, packet)
+            is PluginResponse -> forward(handler, packet)
+            is LoginDisconnect -> forward(handler, packet)
+            is CryptoRequest -> handleCryptoRequest(handler, packet)
+            is LoginSuccess -> handleLoginSuccess(handler, packet)
+            is SetCompression -> handleCompression(handler, packet)
+            is PluginRequest -> forward(handler, packet)
+            else -> throw IllegalArgumentException("Invalid packet!")
         }
     }
 
-    private fun forward(handler: CloudMinecraftHandler, msg: ByteBuf) {
-        msg.resetReaderIndex()
-        handler.other!!.write(msg.retain())
+    private fun handleLoginSuccess(handler: CloudMinecraftHandler, loginSuccess: LoginSuccess) {
+        handler.data.state = PlayState
+        forward(handler, loginSuccess)
     }
 
-    private fun handleLoginSuccess(handler: CloudMinecraftHandler, msg: ByteBuf) {
-        handler.data!!.state = PlayState
-        forward(handler, msg)
-    }
-
-    private fun handleCompression(handler: CloudMinecraftHandler, msg: ByteBuf) {
+    private fun handleCompression(handler: CloudMinecraftHandler, setCompression: SetCompression) {
         val pipe = handler.user.channel!!.pipeline()
-        val threshold = Type.VAR_INT.readPrimitive(msg)
+        val threshold = setCompression.threshold
 
         val backPipe = pipe.get(CloudMinecraftHandler::class.java).other!!.pipeline()
         backPipe.addAfter("frame", "compress", CloudCompressionCodec(threshold))
 
-        forward(handler, msg)
+        forward(handler, setCompression)
 
         pipe.addAfter("frame", "compress", CloudCompressionCodec(threshold))
         pipe.addAfter("frame", "decompress", EmptyChannelHandler()) // ViaRewind compat workaround
     }
 
-    fun handleCryptoRequest(handler: CloudMinecraftHandler, msg: ByteBuf) {
-        val data = handler.data!!
-        data.backServerId = Type.STRING.read(msg)
-        data.backPublicKey = KeyFactory.getInstance("RSA")
-                .generatePublic(X509EncodedKeySpec(Type.BYTE_ARRAY_PRIMITIVE.read(msg)))
-        data.backToken = Type.BYTE_ARRAY_PRIMITIVE.read(msg)
+    fun handleCryptoRequest(handler: CloudMinecraftHandler, cryptoRequest: CryptoRequest) {
+        val data = handler.data
+        data.backServerId = cryptoRequest.serverId
+        data.backPublicKey = cryptoRequest.publicKey
+        data.backToken = cryptoRequest.token
 
         val id = "VIAaaS" + ByteArray(10).let {
             secureRandom.nextBytes(it)
@@ -257,32 +259,27 @@ object LoginState : MinecraftConnectionState {
         data.frontToken = token
         data.frontId = id
 
-        val backMsg = ByteBufAllocator.DEFAULT.buffer()
-        try {
-            backMsg.writeByte(1) // Packet id
-            Type.STRING.write(backMsg, id)
-            Type.BYTE_ARRAY_PRIMITIVE.write(backMsg, mcCryptoKey.public.encoded)
-            Type.BYTE_ARRAY_PRIMITIVE.write(backMsg, token)
-            handler.other!!.write(backMsg.retain())
-        } finally {
-            backMsg.release()
-        }
+        cryptoRequest.serverId = id
+        cryptoRequest.publicKey = mcCryptoKey.public
+        cryptoRequest.token = token
+
+        forward(handler, cryptoRequest)
     }
 
-    fun handleCryptoResponse(handler: CloudMinecraftHandler, msg: ByteBuf) {
+    fun handleCryptoResponse(handler: CloudMinecraftHandler, cryptoResponse: CryptoResponse) {
         val frontHash = let {
-            val frontKey = decryptRsa(mcCryptoKey.private, Type.BYTE_ARRAY_PRIMITIVE.read(msg))
+            val frontKey = decryptRsa(mcCryptoKey.private, cryptoResponse.encryptedKey)
             // RSA token - wat??? why is it encrypted with RSA if it was sent unencrypted?
-            val decryptedToken = decryptRsa(mcCryptoKey.private, Type.BYTE_ARRAY_PRIMITIVE.read(msg))
+            val decryptedToken = decryptRsa(mcCryptoKey.private, cryptoResponse.encryptedToken)
 
-            if (!decryptedToken.contentEquals(handler.data!!.frontToken!!)) throw IllegalStateException("invalid token!")
+            if (!decryptedToken.contentEquals(handler.data.frontToken!!)) throw IllegalStateException("invalid token!")
 
             val aesEn = mcCfb8(frontKey, Cipher.ENCRYPT_MODE)
             val aesDe = mcCfb8(frontKey, Cipher.DECRYPT_MODE)
 
             handler.user.channel!!.pipeline().addBefore("frame", "crypto", CloudCrypto(aesDe, aesEn))
 
-            generateServerHash(handler.data!!.frontId!!, frontKey, mcCryptoKey.public)
+            generateServerHash(handler.data.frontId!!, frontKey, mcCryptoKey.public)
         }
 
         val backKey = ByteArray(16).let {
@@ -290,22 +287,25 @@ object LoginState : MinecraftConnectionState {
             it
         }
 
-        val backHash = generateServerHash(handler.data!!.backServerId!!, backKey, handler.data!!.backPublicKey!!)
+        val backHash = generateServerHash(handler.data.backServerId!!, backKey, handler.data.backPublicKey!!)
 
         handler.user.channel!!.setAutoRead(false)
         GlobalScope.launch(Dispatchers.IO) {
             try {
                 val profile = httpClient.get<JsonObject?>(
-                        "https://sessionserver.mojang.com/session/minecraft/hasJoined?username=" +
-                                "${UrlEscapers.urlFormParameterEscaper().escape(handler.data!!.frontName!!)}&serverId=$frontHash")
-                        ?: throw IllegalArgumentException("Couldn't authenticate with session servers")
+                    "https://sessionserver.mojang.com/session/minecraft/hasJoined?username=" +
+                            "${
+                                UrlEscapers.urlFormParameterEscaper().escape(handler.data.frontName!!)
+                            }&serverId=$frontHash"
+                )
+                    ?: throw IllegalArgumentException("Couldn't authenticate with session servers")
 
                 val sessionJoin = viaWebServer.requestSessionJoin(
-                        fromUndashed(profile.get("id")!!.asString),
-                        handler.data!!.backName!!,
-                        backHash,
-                        handler.address!!, // Frontend handler
-                        handler.data!!.backPublicKey!!
+                    fromUndashed(profile.get("id")!!.asString),
+                    handler.data.backName!!,
+                    backHash,
+                    handler.address!!, // Frontend handler
+                    handler.data.backPublicKey!!
                 )
 
                 val backChan = handler.other!!
@@ -313,21 +313,15 @@ object LoginState : MinecraftConnectionState {
                     if (throwable != null) {
                         handler.disconnect("Online mode error: $throwable")
                     } else {
-                        val backMsg = ByteBufAllocator.DEFAULT.buffer()
-                        try {
-                            backMsg.writeByte(1) // Packet id
-                            Type.BYTE_ARRAY_PRIMITIVE.write(backMsg, encryptRsa(handler.data!!.backPublicKey!!, backKey))
-                            Type.BYTE_ARRAY_PRIMITIVE.write(backMsg, encryptRsa(handler.data!!.backPublicKey!!, handler.data!!.backToken!!))
-                            backChan.writeAndFlush(backMsg.retain())
+                        cryptoResponse.encryptedKey = encryptRsa(handler.data.backPublicKey!!, backKey)
+                        cryptoResponse.encryptedToken =
+                            encryptRsa(handler.data.backPublicKey!!, handler.data.backToken!!)
+                        forward(handler, cryptoResponse)
+                        backChan.flush()
 
-                            val backAesEn = mcCfb8(backKey, Cipher.ENCRYPT_MODE)
-                            val backAesDe = mcCfb8(backKey, Cipher.DECRYPT_MODE)
-
-
-                            backChan.pipeline().addBefore("frame", "crypto", CloudCrypto(backAesDe, backAesEn))
-                        } finally {
-                            backMsg.release()
-                        }
+                        val backAesEn = mcCfb8(backKey, Cipher.ENCRYPT_MODE)
+                        val backAesDe = mcCfb8(backKey, Cipher.DECRYPT_MODE)
+                        backChan.pipeline().addBefore("frame", "crypto", CloudCrypto(backAesDe, backAesEn))
                     }
                 }, backChan.eventLoop())
             } catch (e: Exception) {
@@ -337,17 +331,12 @@ object LoginState : MinecraftConnectionState {
         }
     }
 
-    fun handleLoginStart(handler: CloudMinecraftHandler, msg: ByteBuf) {
-        handler.data!!.frontName = Type.STRING.read(msg)
-        handler.data!!.backName = handler.user.get(CloudData::class.java)!!.altName ?: handler.data!!.frontName
-        val backMsg = ByteBufAllocator.DEFAULT.buffer()
-        try {
-            msg.writeByte(0) // Id
-            Type.STRING.write(msg, handler.data!!.backName)
-            handler.other!!.write(msg.retain())
-        } finally {
-            backMsg.release()
-        }
+    fun handleLoginStart(handler: CloudMinecraftHandler, loginStart: LoginStart) {
+        handler.data.frontName = loginStart.username
+        handler.data.backName = handler.user.get(CloudData::class.java)!!.altName ?: handler.data.frontName
+
+        loginStart.username = handler.data.backName!!
+        forward(handler, loginStart)
     }
 
     override fun disconnect(handler: CloudMinecraftHandler, msg: String) {
@@ -358,8 +347,8 @@ object LoginState : MinecraftConnectionState {
             packet.writeByte(0) // id 0 disconnect
             Type.STRING.write(packet, Gson().toJson("[VIAaaS] §c$msg"))
             handler.user
-                    .sendRawPacketFuture(packet.retain())
-                    .addListener { handler.user.channel?.close() }
+                .sendRawPacketFuture(packet.retain())
+                .addListener { handler.user.channel?.close() }
         } finally {
             packet.release()
         }
@@ -380,10 +369,12 @@ object StatusState : MinecraftConnectionState {
         val packet = ByteBufAllocator.DEFAULT.buffer()
         try {
             packet.writeByte(0) // id 0 disconnect
-            Type.STRING.write(packet, """{"version": {"name": "VIAaaS", "protocol": -1}, "players":
-| {"max": 0, "online": 0, "sample": []}, "description": {"text": ${Gson().toJson("§c$msg")}}}""".trimMargin())
+            Type.STRING.write(
+                packet, """{"version": {"name": "VIAaaS", "protocol": -1}, "players":
+| {"max": 0, "online": 0, "sample": []}, "description": {"text": ${Gson().toJson("§c$msg")}}}""".trimMargin()
+            )
             handler.user.sendRawPacketFuture(packet.retain())
-                    .addListener { handler.user.channel?.close() }
+                .addListener { handler.user.channel?.close() }
         } finally {
             packet.release()
         }
@@ -422,3 +413,32 @@ fun mcCfb8(key: ByteArray, mode: Int): Cipher {
         it
     }
 }
+
+
+fun Channel.setAutoRead(b: Boolean) {
+    this.config().isAutoRead = b
+    if (b) this.read()
+}
+
+fun twosComplementHexdigest(digest: ByteArray): String {
+    return BigInteger(digest).toString(16)
+}
+
+// https://github.com/VelocityPowered/Velocity/blob/0dd6fe1ef2783fe1f9322af06c6fd218aa67cdb1/proxy/src/main/java/com/velocitypowered/proxy/util/EncryptionUtils.java
+fun generateServerHash(serverId: String, sharedSecret: ByteArray?, key: PublicKey): String {
+    val digest = MessageDigest.getInstance("SHA-1")
+    digest.update(serverId.toByteArray(Charsets.ISO_8859_1))
+    digest.update(sharedSecret)
+    digest.update(key.encoded)
+    return twosComplementHexdigest(digest.digest())
+}
+
+private fun forward(handler: CloudMinecraftHandler, packet: Packet) {
+    val msg = ByteBufAllocator.DEFAULT.buffer()
+    try {
+        PacketRegistry.encode(packet, msg, ProtocolVersion.getProtocol(handler.data.protocolId!!))
+        handler.other!!.write(msg.retain())
+    } finally {
+        msg.release()
+    }
+}

src/main/kotlin/com/github/creeper123123321/viaaas/CloudPackets.kt

@@ -0,0 +1,306 @@
+package com.github.creeper123123321.viaaas
+
+import com.google.common.collect.Range
+import io.netty.buffer.ByteBuf
+import us.myles.ViaVersion.api.protocol.ProtocolVersion
+import us.myles.ViaVersion.api.type.Type
+import us.myles.ViaVersion.packets.State
+import java.security.KeyFactory
+import java.security.PublicKey
+import java.security.spec.X509EncodedKeySpec
+import java.util.*
+import java.util.function.Supplier
+import kotlin.properties.Delegates
+
+/**
+ * A mutable object which represents a Minecraft packet data
+ */
+interface Packet {
+    fun decode(byteBuf: ByteBuf, protocolVersion: ProtocolVersion)
+    fun encode(byteBuf: ByteBuf, protocolVersion: ProtocolVersion)
+}
+
+object PacketRegistry {
+    val entries = mutableListOf<RegistryEntry>()
+
+    init {
+        entries.add(
+            RegistryEntry(Range.all(), State.HANDSHAKE, 0, true, ::HandshakePacket, HandshakePacket::class.java)
+        )
+        entries.add(
+            RegistryEntry(Range.all(), State.LOGIN, 0, true, ::LoginStart, LoginStart::class.java)
+        )
+        entries.add(
+            RegistryEntry(Range.all(), State.LOGIN, 1, true, ::CryptoResponse, CryptoResponse::class.java)
+        )
+        entries.add(
+            RegistryEntry(
+                Range.atLeast(ProtocolVersion.v1_13.version),
+                State.LOGIN,
+                2,
+                true,
+                ::PluginResponse,
+                PluginResponse::class.java
+            )
+        )
+        entries.add(
+            RegistryEntry(Range.all(), State.LOGIN, 0, false, ::LoginDisconnect, LoginDisconnect::class.java)
+        )
+        entries.add(
+            RegistryEntry(Range.all(), State.LOGIN, 1, false, ::CryptoRequest, CryptoRequest::class.java)
+        )
+        entries.add(
+            RegistryEntry(Range.all(), State.LOGIN, 2, false, ::LoginSuccess, LoginSuccess::class.java)
+        )
+        entries.add(
+            RegistryEntry(Range.all(), State.LOGIN, 3, false, ::SetCompression, SetCompression::class.java)
+        )
+        entries.add(
+            RegistryEntry(Range.all(), State.LOGIN, 4, false, ::PluginRequest, PluginRequest::class.java)
+        )
+    }
+
+    data class RegistryEntry(
+        val versionRange: Range<Int>,
+        val state: State,
+        val id: Int,
+        val serverBound: Boolean,
+        val constructor: Supplier<Packet>,
+        val packetClass: Class<out Packet>
+    )
+
+    fun getPacketConstructor(
+        protocolVersion: ProtocolVersion,
+        state: State,
+        id: Int,
+        serverBound: Boolean
+    ): Supplier<out Packet>? {
+        return entries.firstOrNull {
+            it.serverBound == serverBound && it.state == state
+                    && it.versionRange.contains(protocolVersion.version) && it.id == id
+        }?.constructor
+    }
+
+    fun getPacketId(packetClass: Class<out Packet>, protocolVersion: ProtocolVersion): Int? {
+        return entries.firstOrNull {
+            it.versionRange.contains(protocolVersion.version) && it.packetClass == packetClass
+        }?.id
+    }
+
+    fun decode(byteBuf: ByteBuf, protocolVersion: ProtocolVersion, state: State, serverBound: Boolean): Packet {
+        val packetId = Type.VAR_INT.readPrimitive(byteBuf)
+        val packet =
+            getPacketConstructor(protocolVersion, state, packetId, serverBound)?.get() ?: UnknownPacket(packetId)
+        packet.decode(byteBuf, protocolVersion)
+        if (byteBuf.isReadable) throw IllegalStateException("Remaining bytes!")
+        return packet
+    }
+
+    fun encode(packet: Packet, byteBuf: ByteBuf, protocolVersion: ProtocolVersion) {
+        val id = if (packet is UnknownPacket) {
+            packet.id
+        } else {
+            getPacketId(packet.javaClass, protocolVersion)!!
+        }
+        Type.VAR_INT.writePrimitive(byteBuf, id)
+        packet.encode(byteBuf, protocolVersion)
+    }
+}
+
+class UnknownPacket(val id: Int) : Packet {
+    lateinit var content: ByteBuf
+
+    override fun decode(byteBuf: ByteBuf, protocolVersion: ProtocolVersion) {
+        content = byteBuf.slice().clear()
+    }
+
+    override fun encode(byteBuf: ByteBuf, protocolVersion: ProtocolVersion) {
+        byteBuf.writeBytes(content)
+    }
+}
+
+// Some code based on https://github.com/VelocityPowered/Velocity/tree/dev/1.1.0/proxy/src/main/java/com/velocitypowered/proxy/protocol/packet
+
+class HandshakePacket : Packet {
+    var protocolId by Delegates.notNull<Int>()
+    lateinit var address: String
+    var port by Delegates.notNull<Int>()
+    lateinit var nextState: State
+
+    override fun decode(byteBuf: ByteBuf, protocolVersion: ProtocolVersion) {
+        protocolId = Type.VAR_INT.readPrimitive(byteBuf)
+        address = Type.STRING.read(byteBuf)
+        port = byteBuf.readUnsignedShort()
+        nextState = State.values()[Type.VAR_INT.readPrimitive(byteBuf)]
+    }
+
+    override fun encode(byteBuf: ByteBuf, protocolVersion: ProtocolVersion) {
+        Type.VAR_INT.writePrimitive(byteBuf, protocolId)
+        Type.STRING.write(byteBuf, address)
+        byteBuf.writeShort(port)
+        byteBuf.writeByte(nextState.ordinal) // var int is too small, fits in a byte
+    }
+}
+
+class LoginStart : Packet {
+    lateinit var username: String
+
+    override fun decode(byteBuf: ByteBuf, protocolVersion: ProtocolVersion) {
+        username = Type.STRING.read(byteBuf)
+    }
+
+    override fun encode(byteBuf: ByteBuf, protocolVersion: ProtocolVersion) {
+        Type.STRING.write(byteBuf, username)
+    }
+}
+
+class CryptoResponse : Packet {
+    lateinit var encryptedKey: ByteArray
+    lateinit var encryptedToken: ByteArray
+
+    override fun decode(byteBuf: ByteBuf, protocolVersion: ProtocolVersion) {
+        if (protocolVersion.version >= ProtocolVersion.v1_8.version) {
+            encryptedKey = Type.BYTE_ARRAY_PRIMITIVE.read(byteBuf)
+            encryptedToken = Type.BYTE_ARRAY_PRIMITIVE.read(byteBuf)
+        } else {
+            encryptedKey = ByteArray(byteBuf.readUnsignedShort()).also { byteBuf.readBytes(it) }
+            encryptedToken = ByteArray(byteBuf.readUnsignedShort()).also { byteBuf.readBytes(it) }
+        }
+    }
+
+    override fun encode(byteBuf: ByteBuf, protocolVersion: ProtocolVersion) {
+        if (protocolVersion.version >= ProtocolVersion.v1_8.version) {
+            Type.BYTE_ARRAY_PRIMITIVE.write(byteBuf, encryptedKey)
+            Type.BYTE_ARRAY_PRIMITIVE.write(byteBuf, encryptedToken)
+        } else {
+            byteBuf.writeShort(encryptedKey.size)
+            byteBuf.writeBytes(encryptedKey)
+            byteBuf.writeShort(encryptedToken.size)
+            byteBuf.writeBytes(encryptedToken)
+        }
+    }
+}
+
+class PluginResponse : Packet {
+    var id by Delegates.notNull<Int>()
+    var success by Delegates.notNull<Boolean>()
+    lateinit var data: ByteBuf
+    override fun decode(byteBuf: ByteBuf, protocolVersion: ProtocolVersion) {
+        id = Type.VAR_INT.readPrimitive(byteBuf)
+        success = byteBuf.readBoolean()
+        if (success) {
+            data = byteBuf.slice().clear()
+        }
+    }
+
+    override fun encode(byteBuf: ByteBuf, protocolVersion: ProtocolVersion) {
+        Type.VAR_INT.writePrimitive(byteBuf, id)
+        byteBuf.writeBoolean(success)
+        if (success) {
+            byteBuf.writeBytes(data)
+        }
+    }
+}
+
+class LoginDisconnect : Packet {
+    lateinit var msg: String
+    override fun decode(byteBuf: ByteBuf, protocolVersion: ProtocolVersion) {
+        msg = Type.STRING.read(byteBuf)
+    }
+
+    override fun encode(byteBuf: ByteBuf, protocolVersion: ProtocolVersion) {
+        Type.STRING.write(byteBuf, msg)
+    }
+}
+
+class CryptoRequest : Packet {
+    lateinit var serverId: String
+    lateinit var publicKey: PublicKey
+    lateinit var token: ByteArray
+
+    override fun decode(byteBuf: ByteBuf, protocolVersion: ProtocolVersion) {
+        serverId = Type.STRING.read(byteBuf)
+        if (protocolVersion.version >= ProtocolVersion.v1_8.version) {
+            publicKey = KeyFactory.getInstance("RSA")
+                .generatePublic(X509EncodedKeySpec(Type.BYTE_ARRAY_PRIMITIVE.read(byteBuf)))
+            token = Type.BYTE_ARRAY_PRIMITIVE.read(byteBuf)
+        } else {
+            publicKey = KeyFactory.getInstance("RSA")
+                .generatePublic(X509EncodedKeySpec(ByteArray(byteBuf.readUnsignedShort()).also { byteBuf.readBytes(it) }))
+            token = ByteArray(byteBuf.readUnsignedShort()).also { byteBuf.readBytes(it) }
+        }
+    }
+
+    override fun encode(byteBuf: ByteBuf, protocolVersion: ProtocolVersion) {
+        Type.STRING.write(byteBuf, serverId)
+        if (protocolVersion.version >= ProtocolVersion.v1_8.version) {
+            Type.BYTE_ARRAY_PRIMITIVE.write(byteBuf, publicKey.encoded)
+            Type.BYTE_ARRAY_PRIMITIVE.write(byteBuf, token)
+        } else {
+            val encodedKey = publicKey.encoded
+            byteBuf.writeShort(encodedKey.size)
+            byteBuf.writeBytes(encodedKey)
+            byteBuf.writeShort(token.size)
+            byteBuf.writeBytes(token)
+        }
+    }
+}
+
+class LoginSuccess : Packet {
+    lateinit var id: UUID
+    lateinit var username: String
+
+    override fun decode(byteBuf: ByteBuf, protocolVersion: ProtocolVersion) {
+        id = when {
+            protocolVersion.version >= ProtocolVersion.v1_16.version -> {
+                Type.UUID_INT_ARRAY.read(byteBuf)
+            }
+            protocolVersion.version >= ProtocolVersion.v1_7_6.version -> {
+                UUID.fromString(Type.STRING.read(byteBuf))
+            }
+            else -> fromUndashed(Type.STRING.read(byteBuf))
+        }
+        username = Type.STRING.read(byteBuf)
+    }
+
+    override fun encode(byteBuf: ByteBuf, protocolVersion: ProtocolVersion) {
+        when {
+            protocolVersion.version >= ProtocolVersion.v1_16.version -> {
+                Type.UUID_INT_ARRAY.write(byteBuf, id)
+            }
+            protocolVersion.version >= ProtocolVersion.v1_7_6.version -> {
+                Type.STRING.write(byteBuf, id.toString())
+            }
+            else -> Type.STRING.write(byteBuf, id.toString().replace("-", ""))
+        }
+        Type.STRING.write(byteBuf, username)
+    }
+}
+
+class SetCompression : Packet {
+    var threshold by Delegates.notNull<Int>()
+    override fun decode(byteBuf: ByteBuf, protocolVersion: ProtocolVersion) {
+        threshold = Type.VAR_INT.readPrimitive(byteBuf)
+    }
+
+    override fun encode(byteBuf: ByteBuf, protocolVersion: ProtocolVersion) {
+        Type.VAR_INT.writePrimitive(byteBuf, threshold)
+    }
+}
+
+class PluginRequest : Packet {
+    var id by Delegates.notNull<Int>()
+    lateinit var channel: String
+    lateinit var data: ByteBuf
+    override fun decode(byteBuf: ByteBuf, protocolVersion: ProtocolVersion) {
+        id = Type.VAR_INT.readPrimitive(byteBuf)
+        channel = Type.STRING.read(byteBuf)
+        data = byteBuf.slice().clear()
+    }
+
+    override fun encode(byteBuf: ByteBuf, protocolVersion: ProtocolVersion) {
+        Type.VAR_INT.writePrimitive(byteBuf, id)
+        Type.STRING.write(byteBuf, channel)
+        byteBuf.writeBytes(data)
+    }
+}

src/main/kotlin/com/github/creeper123123321/viaaas/CloudProtocol.kt

@@ -1,6 +1,5 @@
 package com.github.creeper123123321.viaaas
 
-import io.netty.channel.Channel
 import org.slf4j.LoggerFactory
 import us.myles.ViaVersion.api.PacketWrapper
 import us.myles.ViaVersion.api.data.StoredObject
@@ -11,10 +10,6 @@ import us.myles.ViaVersion.api.protocol.SimpleProtocol
 import us.myles.ViaVersion.api.remapper.PacketRemapper
 import us.myles.ViaVersion.api.type.Type
 import us.myles.ViaVersion.packets.State
-import java.math.BigInteger
-import java.security.MessageDigest
-import java.security.PublicKey
-import java.security.SecureRandom
 
 class CloudPipeline(userConnection: UserConnection) : ProtocolPipeline(userConnection) {
     override fun registerPackets() {
@@ -39,7 +34,8 @@ object CloudHeadProtocol : SimpleProtocol() {
                     val addr = wrapper.read(Type.STRING) // Server Address
                     val receivedPort = wrapper.read(Type.UNSIGNED_SHORT)
 
-                    val parsed = VIAaaSAddress().parse(addr, VIAaaSConfig.hostName)
+                    val parsed = VIAaaSAddress().parse(addr.substringBefore(0.toChar()), VIAaaSConfig.hostName)
+                    if (parsed.viaSuffix == null && VIAaaSConfig.requireHostName) throw IllegalStateException("VIAaaS hostname is required")
                     val backPort = parsed.port ?: receivedPort
                     val backAddr = parsed.realAddress
                     val backProto = parsed.protocol ?: 47
@@ -48,14 +44,17 @@ object CloudHeadProtocol : SimpleProtocol() {
                     wrapper.write(Type.UNSIGNED_SHORT, backPort)
 
                     val playerAddr = wrapper.user().channel!!.pipeline()
-                            .get(CloudMinecraftHandler::class.java)!!.address
+                        .get(CloudMinecraftHandler::class.java)!!.address
                     logger.info("Connecting $playerAddr ($playerVer) -> $backAddr:$backPort ($backProto)")
 
-                    wrapper.user().put(CloudData(
+                    wrapper.user().put(
+                        CloudData(
                             userConnection = wrapper.user(),
                             backendVer = backProto,
                             frontOnline = parsed.online,
-                            altName = parsed.altUsername))
+                            altName = parsed.altUsername
+                        )
+                    )
 
                     wrapper.passthrough(Type.VAR_INT) // Next state
                 }
@@ -64,28 +63,9 @@ object CloudHeadProtocol : SimpleProtocol() {
     }
 }
 
-fun Channel.setAutoRead(b: Boolean) {
-    this.config().isAutoRead = b
-    if (b) this.read()
-}
-
-val secureRandom = SecureRandom.getInstanceStrong()
-
-fun twosComplementHexdigest(digest: ByteArray): String {
-    return BigInteger(digest).toString(16)
-}
-
-// https://github.com/VelocityPowered/Velocity/blob/0dd6fe1ef2783fe1f9322af06c6fd218aa67cdb1/proxy/src/main/java/com/velocitypowered/proxy/util/EncryptionUtils.java
-fun generateServerHash(serverId: String, sharedSecret: ByteArray?, key: PublicKey): String {
-    val digest = MessageDigest.getInstance("SHA-1")
-    digest.update(serverId.toByteArray(Charsets.ISO_8859_1))
-    digest.update(sharedSecret)
-    digest.update(key.encoded)
-    return twosComplementHexdigest(digest.digest())
-}
-
-data class CloudData(val userConnection: UserConnection,
-                     var backendVer: Int,
-                     var frontOnline: Boolean,
-                     var altName: String?
+data class CloudData(
+    val userConnection: UserConnection,
+    var backendVer: Int,
+    var frontOnline: Boolean,
+    var altName: String?
 ) : StoredObject(userConnection)

src/main/kotlin/com/github/creeper123123321/viaaas/VIAaaS.kt

@@ -41,6 +41,7 @@ import us.myles.ViaVersion.util.Config
 import java.io.File
 import java.net.InetAddress
 import java.security.KeyPairGenerator
+import java.security.SecureRandom
 import java.util.*
 import java.util.concurrent.CompletableFuture
 
@@ -60,10 +61,12 @@ val initFuture = CompletableFuture<Unit>()
 
 // Minecraft doesn't have forward secrecy
 val mcCryptoKey = KeyPairGenerator.getInstance("RSA").let {
-    it.initialize(4096) // https://stackoverflow.com/questions/1904516/is-1024-bit-rsa-secure
+    it.initialize(VIAaaSConfig.mcRsaSize) // https://stackoverflow.com/questions/1904516/is-1024-bit-rsa-secure
     it.genKeyPair()
 }
 
+val secureRandom = if (VIAaaSConfig.useStrongRandom) SecureRandom.getInstanceStrong() else SecureRandom()
+
 fun eventLoopGroup(): EventLoopGroup {
     if (VIAaaSConfig.isNativeTransportMc) {
         if (Epoll.isAvailable()) return EpollEventLoopGroup()
@@ -249,6 +252,10 @@ object VIAaaSConfig : Config(File("config/viaaas.yml")) {
     val port: Int get() = this.getInt("port", 25565)
     val bindAddress: String get() = this.getString("bind-address", "localhost")!!
     val hostName: String get() = this.getString("host-name", "viaaas.localhost")!!
+    val mcRsaSize: Int get() = this.getInt("mc-rsa-size", 4096)
+    val useStrongRandom: Boolean get() = this.getBoolean("use-strong-random", true)
+    val blockLocalAddress: Boolean get() = this.getBoolean("block-local-address", true)
+    val requireHostName: Boolean get() = this.getBoolean("require-host-name", true)
 }
 
 class VIAaaSAddress {

src/main/resources/viaaas.yml

@@ -7,4 +7,15 @@ bind-address: localhost
 # Host name of this instance, that will be used in the virtual host
 host-name: viaaas.localhost
 # Use netty native transport for Minecraft when available.
-native-transport-mc: true
+native-transport-mc: true
+# Sets the RSA key size used by client for encrypting the AES symmetric key when using online mode.
+# Minecraft default is 1024. See https://stackoverflow.com/questions/1904516/is-1024-bit-rsa-secure
+mc-rsa-size: 4096
+# Use SecureRandom.getInstanceStrong(). May block if there's not enough entropy when using online mode.
+# See https://wiki.archlinux.org/index.php/Rng-tools
+use-strong-random: true
+# Blocks connection to local addresses
+block-local-address: true
+# Requires virtual host to contain the value from "host-name"
+# A false value could be used for transparent proxying.
+require-host-name: true

src/main/resources/web/auth.html

@@ -11,7 +11,8 @@
     <meta property="og:image" content="https://raw.githubusercontent.com/ViaVersion/ViaVersion/a13c417352298c2269aed8736a76205f0040b705/fabric/src/main/resources/assets/viaversion/textures/squarelogo.png">
     <meta property="og:type" content="game">
     <link rel="icon" href="https://raw.githubusercontent.com/ViaVersion/ViaVersion/a13c417352298c2269aed8736a76205f0040b705/fabric/src/main/resources/assets/viaversion/textures/squarelogo.png">
-    <meta http-equiv="Content-Security-Policy" content="default-src 'self' https://cdnjs.cloudflare.com/; img-src https://*; connect-src 'self' http: https: ws: wss:">
+    <meta http-equiv="Content-Security-Policy" content="default-src 'self' https://cdnjs.cloudflare.com/; img-src https://*; connect-src 'self' http://localhost:*/ https: ws: wss:">
+    <!-- only accept http from localhost -->
     <title>VIAaaS Authenticator</title>
     <link rel="stylesheet" href="style.css">
     <script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.5.1/jquery.min.js"></script>

src/main/resources/web/auth.js

@@ -14,8 +14,8 @@ $(() => {
     var content = document.getElementById("content");
     var acounts = document.getElementById("accounts");
 
-    $("#cors-proxy").val(localStorage.getItem("cors-proxy"));
     $("#cors-proxy").on("change", () => localStorage.setItem('cors-proxy', $("#cors-proxy").val()));
+    $("#cors-proxy").val(localStorage.getItem("cors-proxy"));
     $("#login_submit_mc").on("click", loginMc);
 
     function loginMc() {