Add fuzz targets for OSS-Fuzz integration (RLE + FormulaParser)

build.gradle

@@ -707,7 +707,8 @@ rat {
         // ignore svn conflict artifacts
         "**/module-info.*",
         "poi-examples/src/main/groovy/settings.gradle",
-        "poi-examples/src/main/groovy/.gradle/**"
+        "poi-examples/src/main/groovy/.gradle/**",
+        "**/*.dict"
     ]
 
     /*

build.xml

@@ -291,6 +291,8 @@ under the License.
     <dependency prefix="main.log4j-core" artifact="org.apache.logging.log4j:log4j-core:2.25.3" usage="main-tests"/>
     <dependency prefix="main.commons-logging" artifact="commons-logging:commons-logging:1.2" usage="main-tests"/>
 
+    <dependency prefix="main.jazzer-api" artifact="com.code-intelligence:jazzer-api:0.22.0" usage="main-tests"/>
+
     <dependency prefix="main.ant" artifact="org.apache.ant:ant:1.10.15" usage="excelant"/>
     <dependency prefix="main.antlauncher" artifact="org.apache.ant:ant-launcher:1.10.15" usage="excelant"/>
 
@@ -442,6 +444,7 @@ under the License.
         <pathelement location="${main.objenesis.jar}"/>
         <pathelement location="${main.log4j-core.jar}"/>
         <pathelement location="${main.commons-logging.jar}"/>
+        <pathelement location="${main.jazzer-api.jar}"/>
     </path>
 
     <path id="scratchpad.classpath">

poi/build.gradle

@@ -44,6 +44,7 @@ dependencies {
 
     testImplementation 'org.reflections:reflections:0.10.2'
     testImplementation 'org.apache.ant:ant:1.10.15'
+    testImplementation 'com.code-intelligence:jazzer-api:0.22.0'
 
     testImplementation "org.junit.jupiter:junit-jupiter-api:${junitVersion}"
     testRuntimeOnly "org.junit.jupiter:junit-jupiter-engine:${junitVersion}"

poi/src/test/java/org/apache/poi/fuzz/FormulaParserFuzzer.dict

@@ -0,0 +1,48 @@
+# Excel Formula Dictionary for FormulaParserFuzzer
+"SUM"
+"AVERAGE"
+"COUNT"
+"IF"
+"VLOOKUP"
+"Table1"
+"["
+"]"
+"[["
+"]]"
+"#"
+"#All"
+"#Headers"
+"#Data"
+"#Totals"
+"#This Row"
+"'"
+"!"
+":"
+","
+"("
+")"
+"\""
+"+"
+"-"
+"*"
+"/"
+"^"
+"&"
+"="
+"<"
+">"
+"<="
+">="
+"<>"
+"$"
+"."
+" "
+"@"
+"A1"
+"B2"
+"C3"
+"Sheet1"
+"Sheet2"
+"NamedRange"
+"Column1"
+"Column2"

poi/src/test/java/org/apache/poi/fuzz/FormulaParserFuzzer.java

@@ -0,0 +1,63 @@
+/* ====================================================================
+   Licensed to the Apache Software Foundation (ASF) under one or more
+   contributor license agreements.  See the NOTICE file distributed with
+   this work for additional information regarding copyright ownership.
+   The ASF licenses this file to You under the Apache License, Version 2.0
+   (the "License"); you may not use this file except in compliance with
+   the License.  You may obtain a copy of the License at
+
+       http://www.apache.org/licenses/LICENSE-2.0
+
+   Unless required by applicable law or agreed to in writing, software
+   distributed under the License is distributed on an "AS IS" BASIS,
+   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+   See the License for the specific language governing permissions and
+   limitations under the License.
+==================================================================== */
+
+package org.apache.poi.fuzz;
+
+import com.code_intelligence.jazzer.api.FuzzedDataProvider;
+import org.apache.poi.hssf.usermodel.HSSFEvaluationWorkbook;
+import org.apache.poi.hssf.usermodel.HSSFWorkbook;
+import org.apache.poi.ss.formula.FormulaParser;
+import org.apache.poi.ss.formula.FormulaType;
+import org.apache.poi.ss.formula.FormulaParseException;
+import org.apache.poi.util.RecordFormatException;
+
+import java.nio.BufferUnderflowException;
+import java.util.NoSuchElementException;
+
+/**
+ * Fuzz target for the Apache POI Formula Parser.
+ * Used by Google's OSS-Fuzz for continuous security testing.
+ */
+public class FormulaParserFuzzer {
+    private static HSSFWorkbook workbook;
+    private static HSSFEvaluationWorkbook evalWorkbook;
+
+    public static void fuzzerInitialize() {
+        workbook = new HSSFWorkbook();
+        evalWorkbook = HSSFEvaluationWorkbook.create(workbook);
+    }
+
+    public static void fuzzerTestOneInput(FuzzedDataProvider data) {
+        try {
+            FormulaType formulaType = data.pickValue(FormulaType.values());
+            int sheetIndex = data.consumeInt(-1, 10);
+            String formula = data.consumeRemainingAsString();
+
+            if (formula == null || formula.isEmpty()) {
+                return;
+            }
+
+            FormulaParser.parse(formula, evalWorkbook, formulaType, sheetIndex);
+
+        } catch (FormulaParseException | IllegalArgumentException | IllegalStateException |
+                 IndexOutOfBoundsException | ArithmeticException | NegativeArraySizeException |
+                 RecordFormatException | BufferUnderflowException |
+                 UnsupportedOperationException | NoSuchElementException e) {
+            // Expected exceptions on malformed formula syntax
+        }
+    }
+}

poi/src/test/java/org/apache/poi/fuzz/POIRleFuzzer.java

@@ -0,0 +1,45 @@
+/* ====================================================================
+   Licensed to the Apache Software Foundation (ASF) under one or more
+   contributor license agreements.  See the NOTICE file distributed with
+   this work for additional information regarding copyright ownership.
+   The ASF licenses this file to You under the Apache License, Version 2.0
+   (the "License"); you may not use this file except in compliance with
+   the License.  You may obtain a copy of the License at
+
+       http://www.apache.org/licenses/LICENSE-2.0
+
+   Unless required by applicable law or agreed to in writing, software
+   distributed under the License is distributed on an "AS IS" BASIS,
+   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+   See the License for the specific language governing permissions and
+   limitations under the License.
+==================================================================== */
+
+package org.apache.poi.fuzz;
+
+import org.apache.poi.util.RLEDecompressingInputStream;
+
+import java.io.ByteArrayInputStream;
+import java.io.IOException;
+
+/**
+ * Fuzz target for RLEDecompressingInputStream.
+ * Used by Google's OSS-Fuzz for continuous security testing.
+ */
+public class POIRleFuzzer {
+    public static void fuzzerInitialize() {
+    }
+
+    public static void fuzzerTestOneInput(byte[] input) {
+        try (RLEDecompressingInputStream rleStream =
+                     new RLEDecompressingInputStream(new ByteArrayInputStream(input))) {
+
+            byte[] buffer = new byte[1024];
+            while (rleStream.read(buffer) != -1) {
+                // Trigger decompression logic
+            }
+        } catch (IOException | IllegalArgumentException | IllegalStateException | IndexOutOfBoundsException e) {
+            // Expected exceptions on malformed input
+        }
+    }
+}

poi/src/test/java9/module-info.java

@@ -111,6 +111,7 @@ Licensed to the Apache Software Foundation (ASF) under one or more
     requires org.junit.jupiter.api;
     requires org.junit.jupiter.params;
     requires org.mockito;
+    requires static com.code_intelligence.jazzer.api;
 
     exports org.apache.poi.hpsf.basic to org.junit.platform.commons;
     exports org.apache.poi.hssf.record.pivot to org.junit.platform.commons;