From db6af31395c59e079945df7aa0bf96c471dfc5bc Mon Sep 17 00:00:00 2001
From: skbeh <60107333+skbeh@users.noreply.github.com>
Date: Mon, 19 Aug 2024 12:08:39 +0000
Subject: [PATCH] Apply unicode normalization before checking for spam

This prevents spammers from using visual identical unicode characters
to bypass detection.
---
 .../_4drian3d/chatregulator/api/checks/SpamCheck.java     | 8 +++++---
 .../chatregulator/plugin/impl/StringChainImpl.java        | 4 +++-
 2 files changed, 8 insertions(+), 4 deletions(-)

diff --git a/api/src/main/java/io/github/_4drian3d/chatregulator/api/checks/SpamCheck.java b/api/src/main/java/io/github/_4drian3d/chatregulator/api/checks/SpamCheck.java
index 92a766a..96cfdf3 100644
--- a/api/src/main/java/io/github/_4drian3d/chatregulator/api/checks/SpamCheck.java
+++ b/api/src/main/java/io/github/_4drian3d/chatregulator/api/checks/SpamCheck.java
@@ -10,7 +10,9 @@
 import org.jetbrains.annotations.NotNull;
 import org.jetbrains.annotations.Range;
 
+import java.text.Normalizer;
 import java.util.Iterator;
+import java.util.Locale;
 
 import static java.util.Objects.requireNonNull;
 
@@ -39,13 +41,13 @@ private SpamCheck(final @NotNull SourceType type, int similarLimit) {
         String previous = null;
         while(it.hasNext()) {
             actual = it.next();
-            if (previous != null && !actual.equalsIgnoreCase(previous)) {
+            if (previous != null && !actual.equals(previous)) {
                 return CheckResult.allowed();
             }
             previous = actual;
         }
-		
-        if (chain.last().equalsIgnoreCase(string)) {
+
+        if (chain.last().equals(Normalizer.normalize(string.toLowerCase(Locale.ROOT), Normalizer.Form.NFKD))) {
             return CheckResult.denied(type());
         } else {
             return CheckResult.allowed();
diff --git a/plugin/src/main/java/io/github/_4drian3d/chatregulator/plugin/impl/StringChainImpl.java b/plugin/src/main/java/io/github/_4drian3d/chatregulator/plugin/impl/StringChainImpl.java
index fd6f418..0bf18ae 100644
--- a/plugin/src/main/java/io/github/_4drian3d/chatregulator/plugin/impl/StringChainImpl.java
+++ b/plugin/src/main/java/io/github/_4drian3d/chatregulator/plugin/impl/StringChainImpl.java
@@ -6,9 +6,11 @@
 import io.github._4drian3d.chatregulator.common.configuration.ConfigurationContainer;
 import org.jetbrains.annotations.NotNull;
 
+import java.text.Normalizer;
 import java.time.Instant;
 import java.util.Iterator;
 import java.util.LinkedList;
+import java.util.Locale;
 import java.util.concurrent.atomic.AtomicReference;
 import java.util.concurrent.locks.Lock;
 import java.util.concurrent.locks.ReentrantLock;
@@ -90,7 +92,7 @@ public void executed(final String string) {
     }
 
     private void addExecution(String string) {
-        queue.add(string);
+        queue.add(Normalizer.normalize(string.toLowerCase(Locale.ROOT), Normalizer.Form.NFKD));
         lastExecuted.set(Instant.now());
     }
 }