Bug 66425: Avoid a StackOverflowException found via oss-fuzz

We try to avoid causing StackOverflow, but it was possible
to trigger one here with a specially crafted input-file.

This puts a limit on the number of nested properties in place
and logs a warning when the StyleSheet is not fully parsed.

Should fix https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=61252

git-svn-id: https://svn.apache.org/repos/asf/poi/trunk@1911563 13f79535-47bb-0310-9956-ffa450edef68

poi-scratchpad/src/main/java/org/apache/poi/hwpf/model/StyleSheet.java

@@ -20,6 +20,8 @@ package org.apache.poi.hwpf.model;
 import java.io.IOException;
 import java.io.OutputStream;
 
+import org.apache.logging.log4j.LogManager;
+import org.apache.logging.log4j.Logger;
 import org.apache.poi.hwpf.sprm.CharacterSprmUncompressor;
 import org.apache.poi.hwpf.sprm.ParagraphSprmUncompressor;
 import org.apache.poi.hwpf.usermodel.CharacterProperties;
@@ -39,6 +41,7 @@ import org.apache.poi.util.LittleEndianConsts;
  */
 @Internal
 public final class StyleSheet {
+    private static final Logger LOG = LogManager.getLogger(StyleSheet.class);
 
     public static final int NIL_STYLE = 4095;
 //  private static final int PAP_TYPE = 1;
@@ -46,6 +49,9 @@ public final class StyleSheet {
 //  private static final int SEP_TYPE = 4;
 //  private static final int TAP_TYPE = 5;
 
+    private static final int MAX_PAPX_NESTING = 1000;
+    private static final int MAX_CHPX_NESTING = 1000;
+
     @Deprecated
     private static final ParagraphProperties NIL_PAP = new ParagraphProperties();
     @Deprecated
@@ -114,8 +120,8 @@ public final class StyleSheet {
         }
         for (int x = 0; x < _styleDescriptions.length; x++) {
             if (_styleDescriptions[x] != null) {
-                createPap(x);
-                createChp(x);
+                createPap(x, 0);
+                createChp(x, 0);
             }
         }
     }
@@ -203,7 +209,14 @@ public final class StyleSheet {
      *             ParagraphProperties  from (and also place the finished PAP in)
      */
     @Deprecated
-    private void createPap(int istd) {
+    private void createPap(int istd, int nesting) {
+        if (nesting > MAX_PAPX_NESTING) {
+            LOG.warn("Encountered too deep nesting, cannot fully process stylesheet at " + istd +
+                    " with more than " + MAX_PAPX_NESTING + " nested ParagraphProperties." +
+                    " Some data could not be parsed.");
+            return;
+        }
+
         StyleDescription sd = _styleDescriptions[istd];
         if (sd == null) {
             throw new IllegalStateException("Cannot create Pap, empty styleDescription, had : " + _styleDescriptions.length + " descriptions");
@@ -227,7 +240,7 @@ public final class StyleSheet {
                         throw new IllegalStateException("Pap style " + istd + " claimed to have itself as its parent, which isn't allowed");
                     }
                     // Create the parent style
-                    createPap(baseIndex);
+                    createPap(baseIndex, nesting+1);
                     parentPAP = styleDescription.getPAP();
                 }
 
@@ -253,7 +266,14 @@ public final class StyleSheet {
      *             CharacterProperties object from.
      */
     @Deprecated
-    private void createChp(int istd) {
+    private void createChp(int istd, int nesting) {
+        if (nesting > MAX_CHPX_NESTING) {
+            LOG.warn("Encountered too deep nesting, cannot fully process stylesheet at " + istd +
+                    " with more than " + MAX_CHPX_NESTING + " nested CharacterProperties." +
+                    " Some data could not be parsed.");
+            return;
+        }
+
         StyleDescription sd = _styleDescriptions[istd];
         if (sd == null) {
             throw new IllegalStateException("Cannot create Chp, empty styleDescription, had : " + _styleDescriptions.length + " descriptions");
@@ -282,7 +302,7 @@ public final class StyleSheet {
 
                 parentCHP = styleDescription.getCHP();
                 if (parentCHP == null) {
-                    createChp(baseIndex);
+                    createChp(baseIndex, nesting + 1);
                     parentCHP = styleDescription.getCHP();
                 }
                 if (parentCHP == null) {

poi-scratchpad/src/test/java/org/apache/poi/hwpf/converter/TestWordToConverterSuite.java

@@ -58,7 +58,8 @@ public class TestWordToConverterSuite
         // Corrupt files
         "Fuzzed.doc",
         "clusterfuzz-testcase-minimized-POIHWPFFuzzer-5418937293340672.doc",
-        "TestHPSFWritingFunctionality.doc"
+        "TestHPSFWritingFunctionality.doc",
+        "clusterfuzz-testcase-minimized-POIHWPFFuzzer-4947285593948160.doc"
     );
 
     public static Stream<Arguments> files() {

poi-scratchpad/src/test/java/org/apache/poi/hwpf/converter/TestWordToTextConverter.java

@@ -50,7 +50,8 @@ public class TestWordToTextConverter {
         "TestRobert_Flaherty.doc",
         // Corrupt files
         "clusterfuzz-testcase-minimized-POIHWPFFuzzer-5418937293340672.doc",
-        "TestHPSFWritingFunctionality.doc"
+        "TestHPSFWritingFunctionality.doc",
+        "clusterfuzz-testcase-minimized-POIHWPFFuzzer-4947285593948160.doc"
     );
 
     /**