Fix issues found when fuzzing Apache POI via Jazzer

Add some null-checks and report more meaningful exceptions
This provides a bit more information than simple NullPointExceptions

git-svn-id: https://svn.apache.org/repos/asf/poi/trunk@1895600 13f79535-47bb-0310-9956-ffa450edef68

4 files changed, 44 insertions, 13 deletions

diff --git a/poi-scratchpad/src/main/java/org/apache/poi/hslf/usermodel/HSLFSlideMaster.java b/poi-scratchpad/src/main/java/org/apache/poi/hslf/usermodel/HSLFSlideMaster.java
index dbd5079118..513c8319c3 100644
--- a/poi-scratchpad/src/main/java/org/apache/poi/hslf/usermodel/HSLFSlideMaster.java
+++ b/poi-scratchpad/src/main/java/org/apache/poi/hslf/usermodel/HSLFSlideMaster.java
@@ -143,14 +143,23 @@ public final class HSLFSlideMaster extends HSLFMasterSheet {
         assert (_txmaster == null);
         _txmaster = new TxMasterStyleAtom[9];
 
+        if (getSlideShow() == null || getSlideShow().getDocumentRecord() == null ||
+                getSlideShow().getDocumentRecord().getEnvironment() == null) {
+            throw new IllegalStateException("Did not find a TxMasterStyleAtom in the current slide show");
+        }
+
         TxMasterStyleAtom txdoc = getSlideShow().getDocumentRecord().getEnvironment().getTxMasterStyleAtom();
+        if (txdoc == null) {
+            throw new IllegalStateException("Did not find a TxMasterStyleAtom in the current slide show");
+        }
+
         _txmaster[txdoc.getTextType()] = txdoc;
 
         TxMasterStyleAtom[] txrec = ((MainMaster)getSheetContainer()).getTxMasterStyleAtoms();
-        for (int i = 0; i < txrec.length; i++) {
-            int txType = txrec[i].getTextType();
+        for (TxMasterStyleAtom txMasterStyleAtom : txrec) {
+            int txType = txMasterStyleAtom.getTextType();
             if (txType < _txmaster.length && _txmaster[txType] == null) {
-                _txmaster[txType] = txrec[i];
+                _txmaster[txType] = txMasterStyleAtom;
             }
         }
 
diff --git a/poi-scratchpad/src/main/java/org/apache/poi/hslf/usermodel/HSLFSlideShow.java b/poi-scratchpad/src/main/java/org/apache/poi/hslf/usermodel/HSLFSlideShow.java
index 466f780336..f7c7d4fa7e 100644
--- a/poi-scratchpad/src/main/java/org/apache/poi/hslf/usermodel/HSLFSlideShow.java
+++ b/poi-scratchpad/src/main/java/org/apache/poi/hslf/usermodel/HSLFSlideShow.java
@@ -276,7 +276,9 @@ public final class HSLFSlideShow extends POIDocument implements SlideShow<HSLFSh
                 // Find the Document, and interesting things in it
                 if (record.getRecordType() == RecordTypes.Document.typeID) {
                     _documentRecord = (Document) record;
-                    _fonts = _documentRecord.getEnvironment().getFontCollection();
+                    if (_documentRecord.getEnvironment() != null) {
+                        _fonts = _documentRecord.getEnvironment().getFontCollection();
+                    }
                 }
             } /*else {
                 // No record at this number
@@ -414,6 +416,10 @@ public final class HSLFSlideShow extends POIDocument implements SlideShow<HSLFSh
             int slideId = spa.getSlideIdentifier();
             slideIdToNotes.put(slideId, idx);
 
+            if (notesRecord.getNotesAtom() == null) {
+                throw new IllegalStateException("Could not read NotesAtom from the NotesRecord for " + idx);
+            }
+
             HSLFNotes hn = new HSLFNotes(notesRecord);
             hn.setSlideShow(this);
             _notes.add(hn);
@@ -436,11 +442,16 @@ public final class HSLFSlideShow extends POIDocument implements SlideShow<HSLFSh
 
             // Ensure it really is a slide record
             if (!(r instanceof Slide)) {
-                LOG.atError().log("A Slide SlideAtomSet at {} said its record was at refID {}, but that was actually a {}", box(idx),box(spa.getRefID()),r);
+                LOG.atError().log("A Slide SlideAtomSet at {} said its record was at refID {}, but that was actually a {}",
+                        box(idx), box(spa.getRefID()), r);
                 continue;
             }
 
             Slide slide = (Slide)r;
+            if (slide.getSlideAtom() == null) {
+                LOG.atError().log("SlideAtomSet at {} at refID {} is null", box(idx), box(spa.getRefID()));
+                continue;
+            }
 
             // Do we have a notes for this?
             HSLFNotes notes = null;
diff --git a/poi-scratchpad/src/main/java/org/apache/poi/hslf/usermodel/HSLFSlideShowImpl.java b/poi-scratchpad/src/main/java/org/apache/poi/hslf/usermodel/HSLFSlideShowImpl.java
index 6d35f371da..09dfffbcb9 100644
--- a/poi-scratchpad/src/main/java/org/apache/poi/hslf/usermodel/HSLFSlideShowImpl.java
+++ b/poi-scratchpad/src/main/java/org/apache/poi/hslf/usermodel/HSLFSlideShowImpl.java
@@ -310,10 +310,17 @@ public final class HSLFSlideShowImpl extends POIDocument implements Closeable {
     private void initRecordOffsets(byte[] docstream, int usrOffset, NavigableMap<Integer, Record> recordMap, Map<Integer, Integer> offset2id) {
         while (usrOffset != 0) {
             UserEditAtom usr = (UserEditAtom) Record.buildRecordAtOffset(docstream, usrOffset);
+            if (usr == null) {
+                throw new CorruptPowerPointFileException("Powerpoint document contains no user edit atom");
+            }
+
             recordMap.put(usrOffset, usr);
 
             int psrOffset = usr.getPersistPointersOffset();
             PersistPtrHolder ptr = (PersistPtrHolder) Record.buildRecordAtOffset(docstream, psrOffset);
+            if (ptr == null) {
+                throw new CorruptPowerPointFileException("Powerpoint document is missing a PersistPtrHolder at " + psrOffset);
+            }
             recordMap.put(psrOffset, ptr);
 
             for (Map.Entry<Integer, Integer> entry : ptr.getSlideLocationsLookup().entrySet()) {
diff --git a/poi-scratchpad/src/main/java/org/apache/poi/hslf/usermodel/HSLFTextParagraph.java b/poi-scratchpad/src/main/java/org/apache/poi/hslf/usermodel/HSLFTextParagraph.java
index 318b0ffded..98218e2d23 100644
--- a/poi-scratchpad/src/main/java/org/apache/poi/hslf/usermodel/HSLFTextParagraph.java
+++ b/poi-scratchpad/src/main/java/org/apache/poi/hslf/usermodel/HSLFTextParagraph.java
@@ -1322,14 +1322,18 @@ public final class HSLFTextParagraph implements TextParagraph<HSLFShape,HSLFText
      * For a given PPDrawing, grab all the TextRuns
      */
    public static List<List<HSLFTextParagraph>> findTextParagraphs(PPDrawing ppdrawing, HSLFSheet sheet) {
-        List<List<HSLFTextParagraph>> runsV = new ArrayList<>();
-        for (EscherTextboxWrapper wrapper : ppdrawing.getTextboxWrappers()) {
-            List<HSLFTextParagraph> p = findTextParagraphs(wrapper, sheet);
-            if (p != null) {
-                runsV.add(p);
-            }
-        }
-        return runsV;
+       if (ppdrawing == null) {
+           throw new IllegalArgumentException("Did not receive a valid drawing for sheet " + sheet._getSheetNumber());
+       }
+
+       List<List<HSLFTextParagraph>> runsV = new ArrayList<>();
+       for (EscherTextboxWrapper wrapper : ppdrawing.getTextboxWrappers()) {
+           List<HSLFTextParagraph> p = findTextParagraphs(wrapper, sheet);
+           if (p != null) {
+               runsV.add(p);
+           }
+       }
+       return runsV;
     }
 
     /**