From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: Andrew Steinborn <git@steinborn.me>
Date: Mon, 26 Jul 2021 02:15:17 -0400
Subject: [PATCH] Use Velocity compression and cipher natives


diff --git a/build.gradle.kts b/build.gradle.kts
index 3381ac7c25323d662935c98aa444195c49cf4e8e..5678a9f8d2aa8a7afbc5729570ec297b12acf75d 100644
--- a/build.gradle.kts
+++ b/build.gradle.kts
@@ -44,6 +44,11 @@ dependencies {
     runtimeOnly("org.apache.maven.resolver:maven-resolver-transport-http:1.7.0")
 
     implementation("net.fabricmc:mapping-io:0.3.0") // Paper - needed to read mappings for stacktrace deobfuscation
+    // Paper start - Use Velocity cipher
+    implementation("com.velocitypowered:velocity-native:1.1.0-SNAPSHOT") {
+        isTransitive = false
+    }
+    // Paper end
 
     testImplementation("io.github.classgraph:classgraph:4.8.47") // Paper - mob goal test
     testImplementation("junit:junit:4.13.1")
diff --git a/src/main/java/net/minecraft/network/CipherDecoder.java b/src/main/java/net/minecraft/network/CipherDecoder.java
index 778beb445eac5769b9e4e07b4d1294c50ae2602b..c712fb8193115e1ab71b5e40fb0ccb9413062b03 100644
--- a/src/main/java/net/minecraft/network/CipherDecoder.java
+++ b/src/main/java/net/minecraft/network/CipherDecoder.java
@@ -7,13 +7,29 @@ import java.util.List;
 import javax.crypto.Cipher;
 
 public class CipherDecoder extends MessageToMessageDecoder<ByteBuf> {
-    private final CipherBase cipher;
+    private final com.velocitypowered.natives.encryption.VelocityCipher cipher; // Paper
 
-    public CipherDecoder(Cipher cipher) {
-        this.cipher = new CipherBase(cipher);
+    public CipherDecoder(com.velocitypowered.natives.encryption.VelocityCipher cipher) {  // Paper
+        this.cipher = cipher;  // Paper
     }
 
     protected void decode(ChannelHandlerContext channelHandlerContext, ByteBuf byteBuf, List<Object> list) throws Exception {
-        list.add(this.cipher.decipher(channelHandlerContext, byteBuf));
+        // Paper start
+        ByteBuf compatible = com.velocitypowered.natives.util.MoreByteBufUtils.ensureCompatible(channelHandlerContext.alloc(), cipher, byteBuf);
+        try {
+            cipher.process(compatible);
+            list.add(compatible);
+        } catch (Exception e) {
+            compatible.release(); // compatible will never be used if we throw an exception
+            throw e;
+        }
+        // Paper end
     }
+
+    // Paper start
+    @Override
+    public void handlerRemoved(ChannelHandlerContext ctx) throws Exception {
+        cipher.close();
+    }
+    // Paper end
 }
diff --git a/src/main/java/net/minecraft/network/CipherEncoder.java b/src/main/java/net/minecraft/network/CipherEncoder.java
index 0f3d502a9680006bcdcd7d272240a2e5c3b46790..5dd7be70603e8754d2625bb9d16900cb01b9c730 100644
--- a/src/main/java/net/minecraft/network/CipherEncoder.java
+++ b/src/main/java/net/minecraft/network/CipherEncoder.java
@@ -4,15 +4,32 @@ import io.netty.buffer.ByteBuf;
 import io.netty.channel.ChannelHandlerContext;
 import io.netty.handler.codec.MessageToByteEncoder;
 import javax.crypto.Cipher;
+import java.util.List;
 
-public class CipherEncoder extends MessageToByteEncoder<ByteBuf> {
-    private final CipherBase cipher;
+public class CipherEncoder extends io.netty.handler.codec.MessageToMessageEncoder<ByteBuf> { // Paper - change superclass
+    private final com.velocitypowered.natives.encryption.VelocityCipher cipher; // Paper
 
-    public CipherEncoder(Cipher cipher) {
-        this.cipher = new CipherBase(cipher);
+    public CipherEncoder(com.velocitypowered.natives.encryption.VelocityCipher cipher) {  // Paper
+        this.cipher = cipher;  // Paper
     }
 
-    protected void encode(ChannelHandlerContext channelHandlerContext, ByteBuf byteBuf, ByteBuf byteBuf2) throws Exception {
-        this.cipher.encipher(byteBuf, byteBuf2);
+    protected void encode(ChannelHandlerContext channelHandlerContext, ByteBuf byteBuf, List<Object> list) throws Exception {
+        // Paper start
+        ByteBuf compatible = com.velocitypowered.natives.util.MoreByteBufUtils.ensureCompatible(channelHandlerContext.alloc(), cipher, byteBuf);
+        try {
+            cipher.process(compatible);
+            list.add(compatible);
+        } catch (Exception e) {
+            compatible.release(); // compatible will never be used if we throw an exception
+            throw e;
+        }
+        // Paper end
     }
+
+    // Paper start
+    @Override
+    public void handlerRemoved(ChannelHandlerContext ctx) throws Exception {
+        cipher.close();
+    }
+    // Paper end
 }
diff --git a/src/main/java/net/minecraft/network/CompressionDecoder.java b/src/main/java/net/minecraft/network/CompressionDecoder.java
index b62be99c57b0a5bba0dc29809557d4d247698b13..f4d4ad983baf24d889441541d5a84dc1f49ea4d4 100644
--- a/src/main/java/net/minecraft/network/CompressionDecoder.java
+++ b/src/main/java/net/minecraft/network/CompressionDecoder.java
@@ -12,13 +12,20 @@ public class CompressionDecoder extends ByteToMessageDecoder {
     public static final int MAXIMUM_COMPRESSED_LENGTH = 2097152;
     public static final int MAXIMUM_UNCOMPRESSED_LENGTH = 8388608;
     private final Inflater inflater;
+    private final com.velocitypowered.natives.compression.VelocityCompressor compressor; // Paper
     private int threshold;
     private boolean validateDecompressed;
 
+    // Paper start
     public CompressionDecoder(int compressionThreshold, boolean rejectsBadPackets) {
+        this(null, compressionThreshold, rejectsBadPackets);
+    }
+    public CompressionDecoder(com.velocitypowered.natives.compression.VelocityCompressor compressor, int compressionThreshold, boolean rejectsBadPackets) {
         this.threshold = compressionThreshold;
         this.validateDecompressed = rejectsBadPackets;
-        this.inflater = new Inflater();
+        this.inflater = compressor == null ? new Inflater() : null;
+        this.compressor = compressor;
+        // Paper end
     }
 
     protected void decode(ChannelHandlerContext channelHandlerContext, ByteBuf byteBuf, List<Object> list) throws Exception {
@@ -38,6 +45,8 @@ public class CompressionDecoder extends ByteToMessageDecoder {
                     }
                 }
 
+                // Paper start
+                if (this.inflater != null) {
                 byte[] bs = new byte[friendlyByteBuf.readableBytes()];
                 friendlyByteBuf.readBytes(bs);
                 this.inflater.setInput(bs);
@@ -45,10 +54,36 @@ public class CompressionDecoder extends ByteToMessageDecoder {
                 this.inflater.inflate(cs);
                 list.add(Unpooled.wrappedBuffer(cs));
                 this.inflater.reset();
+                    return;
+                }
+
+                int claimedUncompressedSize = i; // OBFHELPER
+                ByteBuf compatibleIn = com.velocitypowered.natives.util.MoreByteBufUtils.ensureCompatible(channelHandlerContext.alloc(), this.compressor, byteBuf);
+                ByteBuf uncompressed = com.velocitypowered.natives.util.MoreByteBufUtils.preferredBuffer(channelHandlerContext.alloc(), this.compressor, claimedUncompressedSize);
+                try {
+                    this.compressor.inflate(compatibleIn, uncompressed, claimedUncompressedSize);
+                    list.add(uncompressed);
+                    byteBuf.clear();
+                } catch (Exception e) {
+                    uncompressed.release();
+                    throw e;
+                } finally {
+                    compatibleIn.release();
+                }
+                // Paper end
             }
         }
     }
 
+    // Paper start
+    @Override
+    public void handlerRemoved0(ChannelHandlerContext ctx) throws Exception {
+        if (this.compressor != null) {
+            this.compressor.close();
+        }
+    }
+    // Paper end
+
     public void setThreshold(int compressionThreshold, boolean rejectsBadPackets) {
         this.threshold = compressionThreshold;
         this.validateDecompressed = rejectsBadPackets;
diff --git a/src/main/java/net/minecraft/network/CompressionEncoder.java b/src/main/java/net/minecraft/network/CompressionEncoder.java
index 792883afe53d2b7989c25a81c2f9a639d5e21d20..c04379ca8a4db0f4de46ad2b3b3384310eebddf3 100644
--- a/src/main/java/net/minecraft/network/CompressionEncoder.java
+++ b/src/main/java/net/minecraft/network/CompressionEncoder.java
@@ -6,22 +6,37 @@ import io.netty.handler.codec.MessageToByteEncoder;
 import java.util.zip.Deflater;
 
 public class CompressionEncoder extends MessageToByteEncoder<ByteBuf> {
-    private final byte[] encodeBuf = new byte[8192];
+    private final byte[] encodeBuf; // Paper
     private final Deflater deflater;
+    private final com.velocitypowered.natives.compression.VelocityCompressor compressor; // Paper
     private int threshold;
 
+    // Paper start
     public CompressionEncoder(int compressionThreshold) {
+        this(null, compressionThreshold);
+    }
+    public CompressionEncoder(com.velocitypowered.natives.compression.VelocityCompressor compressor, int compressionThreshold) {
         this.threshold = compressionThreshold;
-        this.deflater = new Deflater();
+        if (compressor == null) {
+            this.encodeBuf = new byte[8192];
+            this.deflater = new Deflater();
+        } else {
+            this.encodeBuf = null;
+            this.deflater = null;
+        }
+        this.compressor = compressor;
+        // Paper end
     }
 
-    protected void encode(ChannelHandlerContext channelHandlerContext, ByteBuf byteBuf, ByteBuf byteBuf2) {
+    protected void encode(ChannelHandlerContext channelHandlerContext, ByteBuf byteBuf, ByteBuf byteBuf2) throws Exception { // Paper
         int i = byteBuf.readableBytes();
         FriendlyByteBuf friendlyByteBuf = new FriendlyByteBuf(byteBuf2);
         if (i < this.threshold) {
             friendlyByteBuf.writeVarInt(0);
             friendlyByteBuf.writeBytes(byteBuf);
         } else {
+            // Paper start
+            if (this.deflater != null) {
             byte[] bs = new byte[i];
             byteBuf.readBytes(bs);
             friendlyByteBuf.writeVarInt(bs.length);
@@ -34,10 +49,48 @@ public class CompressionEncoder extends MessageToByteEncoder<ByteBuf> {
             }
 
             this.deflater.reset();
+                return;
+            }
+
+            friendlyByteBuf.writeVarInt(i);
+            ByteBuf compatibleIn = com.velocitypowered.natives.util.MoreByteBufUtils.ensureCompatible(channelHandlerContext.alloc(), this.compressor, byteBuf);
+            try {
+                this.compressor.deflate(compatibleIn, byteBuf2);
+            } finally {
+                compatibleIn.release();
+            }
+            // Paper end
         }
 
     }
 
+    // Paper start
+    @Override
+    protected ByteBuf allocateBuffer(ChannelHandlerContext ctx, ByteBuf msg, boolean preferDirect) throws Exception{
+        if (this.compressor != null) {
+            // We allocate bytes to be compressed plus 1 byte. This covers two cases:
+            //
+            // - Compression
+            //    According to https://github.com/ebiggers/libdeflate/blob/master/libdeflate.h#L103,
+            //    if the data compresses well (and we do not have some pathological case) then the maximum
+            //    size the compressed size will ever be is the input size minus one.
+            // - Uncompressed
+            //    This is fairly obvious - we will then have one more than the uncompressed size.
+            int initialBufferSize = msg.readableBytes() + 1;
+            return com.velocitypowered.natives.util.MoreByteBufUtils.preferredBuffer(ctx.alloc(), this.compressor, initialBufferSize);
+        }
+
+        return super.allocateBuffer(ctx, msg, preferDirect);
+    }
+
+    @Override
+    public void handlerRemoved(ChannelHandlerContext ctx) throws Exception {
+        if (this.compressor != null) {
+            this.compressor.close();
+        }
+    }
+    // Paper end
+
     public int getThreshold() {
         return this.threshold;
     }
diff --git a/src/main/java/net/minecraft/network/Connection.java b/src/main/java/net/minecraft/network/Connection.java
index a1aafb037fd340dc93dd2afb758ffc7457d15f84..a7e7fe4be2784ff34f7f8d0b6c2f82d65de8c145 100644
--- a/src/main/java/net/minecraft/network/Connection.java
+++ b/src/main/java/net/minecraft/network/Connection.java
@@ -628,11 +628,28 @@ public class Connection extends SimpleChannelInboundHandler<Packet<?>> {
         return networkmanager;
     }
 
-    public void setEncryptionKey(Cipher decryptionCipher, Cipher encryptionCipher) {
-        this.encrypted = true;
-        this.channel.pipeline().addBefore("splitter", "decrypt", new CipherDecoder(decryptionCipher));
-        this.channel.pipeline().addBefore("prepender", "encrypt", new CipherEncoder(encryptionCipher));
+    // Paper start
+//    public void setEncryptionKey(Cipher decryptionCipher, Cipher encryptionCipher) {
+//        this.encrypted = true;
+//        this.channel.pipeline().addBefore("splitter", "decrypt", new CipherDecoder(decryptionCipher));
+//        this.channel.pipeline().addBefore("prepender", "encrypt", new CipherEncoder(encryptionCipher));
+//    }
+
+    public void setupEncryption(javax.crypto.SecretKey key) throws net.minecraft.util.CryptException {
+        if (!this.encrypted) {
+            try {
+                com.velocitypowered.natives.encryption.VelocityCipher decryption = com.velocitypowered.natives.util.Natives.cipher.get().forDecryption(key);
+                com.velocitypowered.natives.encryption.VelocityCipher encryption = com.velocitypowered.natives.util.Natives.cipher.get().forEncryption(key);
+
+                this.encrypted = true;
+                this.channel.pipeline().addBefore("splitter", "decrypt", new CipherDecoder(decryption));
+                this.channel.pipeline().addBefore("prepender", "encrypt", new CipherEncoder(encryption));
+            } catch (java.security.GeneralSecurityException e) {
+                throw new net.minecraft.util.CryptException(e);
+            }
+        }
     }
+    // Paper end
 
     public boolean isEncrypted() {
         return this.encrypted;
@@ -661,16 +678,17 @@ public class Connection extends SimpleChannelInboundHandler<Packet<?>> {
 
     public void setupCompression(int compressionThreshold, boolean rejectsBadPackets) {
         if (compressionThreshold >= 0) {
+            com.velocitypowered.natives.compression.VelocityCompressor compressor = com.velocitypowered.natives.util.Natives.compress.get().create(-1); // Paper
             if (this.channel.pipeline().get("decompress") instanceof CompressionDecoder) {
                 ((CompressionDecoder) this.channel.pipeline().get("decompress")).setThreshold(compressionThreshold, rejectsBadPackets);
             } else {
-                this.channel.pipeline().addBefore("decoder", "decompress", new CompressionDecoder(compressionThreshold, rejectsBadPackets));
+                this.channel.pipeline().addBefore("decoder", "decompress", new CompressionDecoder(compressor, compressionThreshold, rejectsBadPackets)); // Paper
             }
 
             if (this.channel.pipeline().get("compress") instanceof CompressionEncoder) {
                 ((CompressionEncoder) this.channel.pipeline().get("compress")).setThreshold(compressionThreshold);
             } else {
-                this.channel.pipeline().addBefore("encoder", "compress", new CompressionEncoder(compressionThreshold));
+                this.channel.pipeline().addBefore("encoder", "compress", new CompressionEncoder(compressor, compressionThreshold)); // Paper
             }
         } else {
             if (this.channel.pipeline().get("decompress") instanceof CompressionDecoder) {
diff --git a/src/main/java/net/minecraft/server/network/ServerConnectionListener.java b/src/main/java/net/minecraft/server/network/ServerConnectionListener.java
index f7aa0125e4724f1efddf28814f926289c1ae37d4..477aa83c3b342705a8a9b7ab41b2f77008e2e281 100644
--- a/src/main/java/net/minecraft/server/network/ServerConnectionListener.java
+++ b/src/main/java/net/minecraft/server/network/ServerConnectionListener.java
@@ -104,6 +104,11 @@ public class ServerConnectionListener {
                 ServerConnectionListener.LOGGER.info("Using default channel type");
             }
 
+            // Paper start - indicate Velocity natives in use
+            ServerConnectionListener.LOGGER.info("Paper: Using " + com.velocitypowered.natives.util.Natives.compress.getLoadedVariant() + " compression from Velocity.");
+            ServerConnectionListener.LOGGER.info("Paper: Using " + com.velocitypowered.natives.util.Natives.cipher.getLoadedVariant() + " cipher from Velocity.");
+            // Paper end
+
             this.channels.add(((ServerBootstrap) ((ServerBootstrap) (new ServerBootstrap()).channel(oclass)).childHandler(new ChannelInitializer<Channel>() {
                 protected void initChannel(Channel channel) {
                     try {
diff --git a/src/main/java/net/minecraft/server/network/ServerLoginPacketListenerImpl.java b/src/main/java/net/minecraft/server/network/ServerLoginPacketListenerImpl.java
index 45db764f4499ee71bef691d37b604f21da120fe7..d2dd8b802ecea7fd2efe5f07fcef65c26e1adfbc 100644
--- a/src/main/java/net/minecraft/server/network/ServerLoginPacketListenerImpl.java
+++ b/src/main/java/net/minecraft/server/network/ServerLoginPacketListenerImpl.java
@@ -276,12 +276,14 @@ public class ServerLoginPacketListenerImpl implements ServerLoginPacketListener
             }
 
             SecretKey secretkey = packet.getSecretKey(privatekey);
-            Cipher cipher = Crypt.getCipher(2, secretkey);
-            Cipher cipher1 = Crypt.getCipher(1, secretkey);
+            // Paper start
+//            Cipher cipher = Crypt.getCipher(2, secretkey);
+//            Cipher cipher1 = Crypt.getCipher(1, secretkey);
+            // Paper end
 
             s = (new BigInteger(Crypt.digestData("", this.server.getKeyPair().getPublic(), secretkey))).toString(16);
             this.state = ServerLoginPacketListenerImpl.State.AUTHENTICATING;
-            this.connection.setEncryptionKey(cipher, cipher1);
+            this.connection.setupEncryption(secretkey); // Paper
         } catch (CryptException cryptographyexception) {
             throw new IllegalStateException("Protocol error", cryptographyexception);
         }
