Add option to validate decompression

Author: Camotoy

src/main/java/com/github/steveice10/packetlib/Session.java

@@ -159,14 +159,15 @@ public interface Session {
      *
      * @return This session's compression threshold.
      */
-    public int getCompressionThreshold();
+    int getCompressionThreshold();
 
     /**
      * Sets the compression packet length threshold for this session (-1 = disabled).
      *
      * @param threshold The new compression threshold.
+     * @param validateDecompression whether to validate that the decompression fits within size checks.
      */
-    public void setCompressionThreshold(int threshold);
+    void setCompressionThreshold(int threshold, boolean validateDecompression);
 
     /**
      * Enables encryption for this session.

src/main/java/com/github/steveice10/packetlib/tcp/TcpPacketCompression.java

@@ -20,9 +20,11 @@ public class TcpPacketCompression extends ByteToMessageCodec<ByteBuf> {
     private final Deflater deflater = new Deflater();
     private final Inflater inflater = new Inflater();
     private final byte[] buf = new byte[8192];
+    private final boolean validateDecompression;
 
-    public TcpPacketCompression(Session session) {
+    public TcpPacketCompression(Session session, boolean validateDecompression) {
         this.session = session;
+        this.validateDecompression = validateDecompression;
     }
 
     @Override
@@ -63,12 +65,14 @@ protected void decode(ChannelHandlerContext ctx, ByteBuf buf, List<Object> out)
             if(size == 0) {
                 out.add(buf.readBytes(buf.readableBytes()));
             } else {
-                if(size < this.session.getCompressionThreshold()) {
-                    throw new DecoderException("Badly compressed packet: size of " + size + " is below threshold of " + this.session.getCompressionThreshold() + ".");
-                }
+                if (validateDecompression) { // This is sectioned off as of at least Java Edition 1.18
+                    if (size < this.session.getCompressionThreshold()) {
+                        throw new DecoderException("Badly compressed packet: size of " + size + " is below threshold of " + this.session.getCompressionThreshold() + ".");
+                    }
 
-                if(size > MAX_COMPRESSED_SIZE) {
-                    throw new DecoderException("Badly compressed packet: size of " + size + " is larger than protocol maximum of " + MAX_COMPRESSED_SIZE + ".");
+                    if (size > MAX_COMPRESSED_SIZE) {
+                        throw new DecoderException("Badly compressed packet: size of " + size + " is larger than protocol maximum of " + MAX_COMPRESSED_SIZE + ".");
+                    }
                 }
 
                 byte[] bytes = new byte[buf.readableBytes()];

src/main/java/com/github/steveice10/packetlib/tcp/TcpSession.java

@@ -177,12 +177,12 @@ public int getCompressionThreshold() {
     }
 
     @Override
-    public void setCompressionThreshold(int threshold) {
+    public void setCompressionThreshold(int threshold, boolean validateDecompression) {
         this.compressionThreshold = threshold;
         if (this.channel != null) {
             if (this.compressionThreshold >= 0) {
                 if (this.channel.pipeline().get("compression") == null) {
-                    this.channel.pipeline().addBefore("codec", "compression", new TcpPacketCompression(this));
+                    this.channel.pipeline().addBefore("codec", "compression", new TcpPacketCompression(this, validateDecompression));
                 }
             } else if (this.channel.pipeline().get("compression") != null) {
                 this.channel.pipeline().remove("compression");