Bug 66425: Avoid exceptions found via poi-fuzz

We try to avoid throwing NullPointerException, ClassCastExceptions 
and StackOverflowException, but it was possible to trigger them

Also improve some exception messages

Fixes https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=62698
https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=62606
https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=62685

git-svn-id: https://svn.apache.org/repos/asf/poi/trunk@1912707 13f79535-47bb-0310-9956-ffa450edef68

3 files changed, 12 insertions, 4 deletions

diff --git a/poi-ooxml/src/main/java/org/apache/poi/xslf/usermodel/XSLFGraphicFrame.java b/poi-ooxml/src/main/java/org/apache/poi/xslf/usermodel/XSLFGraphicFrame.java
index ceccd10635..c744f2ab73 100644
--- a/poi-ooxml/src/main/java/org/apache/poi/xslf/usermodel/XSLFGraphicFrame.java
+++ b/poi-ooxml/src/main/java/org/apache/poi/xslf/usermodel/XSLFGraphicFrame.java
@@ -67,6 +67,10 @@ public class XSLFGraphicFrame extends XSLFShape implements GraphicalFrame<XSLFSh
     @Override
     public Rectangle2D getAnchor(){
         CTTransform2D xfrm = ((CTGraphicalObjectFrame)getXmlObject()).getXfrm();
+        if (xfrm == null) {
+            throw new IllegalArgumentException("Could not retrieve an Xfrm from the XML object");
+        }
+
         CTPoint2D off = xfrm.getOff();
         double x = Units.toPoints(POIXMLUnits.parseLength(off.xgetX()));
         double y = Units.toPoints(POIXMLUnits.parseLength(off.xgetY()));
diff --git a/poi-ooxml/src/main/java/org/apache/poi/xslf/usermodel/XSLFTableCell.java b/poi-ooxml/src/main/java/org/apache/poi/xslf/usermodel/XSLFTableCell.java
index f84c37d08e..d22ab8df19 100644
--- a/poi-ooxml/src/main/java/org/apache/poi/xslf/usermodel/XSLFTableCell.java
+++ b/poi-ooxml/src/main/java/org/apache/poi/xslf/usermodel/XSLFTableCell.java
@@ -766,7 +766,7 @@ public class XSLFTableCell extends XSLFTextShape implements TableCell<XSLFShape,
                 return super.isBold();
             } else {
                 final CTTextCharacterProperties rPr = super.getRPr(false);
-                if (rPr.isSetB()) {
+                if (rPr != null && rPr.isSetB()) {
                     // If this run has bold set locally, then it overrides table cell style.
                     return rPr.getB();
                 } else {
@@ -784,7 +784,7 @@ public class XSLFTableCell extends XSLFTextShape implements TableCell<XSLFShape,
                 return super.isItalic();
             } else {
                 final CTTextCharacterProperties rPr = super.getRPr(false);
-                if (rPr.isSetI()) {
+                if (rPr != null && rPr.isSetI()) {
                     // If this run has italic set locally, then it overrides table cell style.
                     return rPr.getI();
                 } else {
diff --git a/poi-ooxml/src/main/java/org/apache/poi/xssf/streaming/SXSSFSheet.java b/poi-ooxml/src/main/java/org/apache/poi/xssf/streaming/SXSSFSheet.java
index ea1c7e1bfb..f74e6b0dbb 100644
--- a/poi-ooxml/src/main/java/org/apache/poi/xssf/streaming/SXSSFSheet.java
+++ b/poi-ooxml/src/main/java/org/apache/poi/xssf/streaming/SXSSFSheet.java
@@ -96,8 +96,12 @@ public class SXSSFSheet implements Sheet, OoxmlSheetExtensions {
         setRandomAccessWindowSize(_workbook.getRandomAccessWindowSize());
         try {
             _autoSizeColumnTracker = new AutoSizeColumnTracker(this);
-        } catch (UnsatisfiedLinkError | InternalError e) {
-            LOG.atWarn().log("Failed to create AutoSizeColumnTracker, possibly due to fonts not being installed in your OS", e);
+        } catch (UnsatisfiedLinkError | NoClassDefFoundError | InternalError |
+                 // thrown when no fonts are available in the workbook
+                 IndexOutOfBoundsException e) {
+            LOG.atWarn()
+                    .withThrowable(e)
+                    .log("Failed to create AutoSizeColumnTracker, possibly due to fonts not being installed in your OS");
         }
     }