From 527176c908edc43ef7e49bd37631e9c746dc8a36 Mon Sep 17 00:00:00 2001
From: John Jiang <johnsjiang@tencent.com>
Date: Wed, 27 Nov 2024 11:41:43 +0800
Subject: [PATCH] TKSS-926: Backport JDK-8331682: Slow networks/Impatient
 clients can potentially send unencrypted TLSv1.3 alerts that won't parse on
 the server

---
 .../kona/sun/security/ssl/SSLCipher.java      | 20 ++++++++++++++-----
 1 file changed, 15 insertions(+), 5 deletions(-)

diff --git a/kona-ssl/src/main/java/com/tencent/kona/sun/security/ssl/SSLCipher.java b/kona-ssl/src/main/java/com/tencent/kona/sun/security/ssl/SSLCipher.java
index 367e071b..e86376f6 100644
--- a/kona-ssl/src/main/java/com/tencent/kona/sun/security/ssl/SSLCipher.java
+++ b/kona-ssl/src/main/java/com/tencent/kona/sun/security/ssl/SSLCipher.java
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2018, 2022, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2018, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -1900,10 +1900,20 @@ public Plaintext decrypt(byte contentType, ByteBuffer bb,
                 }
 
                 if (bb.remaining() <= tagSize) {
-                    throw new BadPaddingException(
-                        "Insufficient buffer remaining for AEAD cipher " +
-                        "fragment (" + bb.remaining() + "). Needs to be " +
-                        "more than tag size (" + tagSize + ")");
+                    // Check for unexpected plaintext alert.
+                    if (contentType == ContentType.ALERT.id
+                            && bb.remaining() == 2) {
+                        throw new GeneralSecurityException(String.format(
+                                "Unexpected plaintext alert received: " +
+                                "Level: %s; Alert: %s",
+                                Alert.Level.nameOf(bb.get(bb.position())),
+                                Alert.nameOf(bb.get(bb.position() + 1))));
+                    } else {
+                        throw new BadPaddingException(
+                                "Insufficient buffer remaining for AEAD cipher " +
+                                "fragment (" + bb.remaining() + "). Needs to be " +
+                                "more than tag size (" + tagSize + ")");
+                    }
                 }
 
                 byte[] sn = sequence;