Bug 66425: Avoid exceptions found via poi-fuzz

Prevent NullPointerException

Fixes https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=64212

git-svn-id: https://svn.apache.org/repos/asf/poi/trunk@1915006 13f79535-47bb-0310-9956-ffa450edef68

poi/src/main/java/org/apache/poi/hssf/record/FeatRecord.java

@@ -132,13 +132,15 @@ public final class FeatRecord extends StandardRecord {
             cellRef.serialize(out);
         }
 
-        sharedFeature.serialize(out);
+        if (sharedFeature != null) {
+            sharedFeature.serialize(out);
+        }
     }
 
     protected int getDataSize() {
         return 12 + 2+1+4+2+4+2+
-            (cellRefs.length * CellRangeAddress.ENCODED_SIZE)
-            +sharedFeature.getDataSize();
+            (cellRefs.length * CellRangeAddress.ENCODED_SIZE) +
+                (sharedFeature == null ? 0 : sharedFeature.getDataSize());
     }
 
     public int getIsf_sharedFeatureType() {

poi/src/test/java/org/apache/poi/hssf/dev/TestBiffViewer.java

@@ -45,6 +45,7 @@ class TestBiffViewer extends BaseTestIteratingXLS {
         excludes.put("clusterfuzz-testcase-minimized-POIHSSFFuzzer-5786329142919168.xls", IllegalStateException.class);
         excludes.put("clusterfuzz-testcase-minimized-POIHSSFFuzzer-5889658057523200.xls", IndexOutOfBoundsException.class);
         excludes.put("clusterfuzz-testcase-minimized-POIHSSFFuzzer-5175219985448960.xls", IndexOutOfBoundsException.class);
+        excludes.put("clusterfuzz-testcase-minimized-POIHSSFFuzzer-6137883240824832.xls", IndexOutOfBoundsException.class);
 
         return excludes;
     }

poi/src/test/java/org/apache/poi/hssf/dev/TestRecordLister.java

@@ -48,6 +48,8 @@ class TestRecordLister extends BaseTestIteratingXLS {
         excludes.put("clusterfuzz-testcase-minimized-POIHSSFFuzzer-5786329142919168.xls", RecordFormatException.class);
         excludes.put("clusterfuzz-testcase-minimized-POIHSSFFuzzer-5889658057523200.xls", IndexOutOfBoundsException.class);
         excludes.put("clusterfuzz-testcase-minimized-POIHSSFFuzzer-5175219985448960.xls", RecordFormatException.class);
+        excludes.put("clusterfuzz-testcase-minimized-POIHSSFFuzzer-6137883240824832.xls", RecordFormatException.class);
+
         return excludes;
     }