Use PdfCatalog#getOutlines methods instead of PdfAChecker implementation to prevent SO exception during reading complex outline structure

DEVSIX-1822

Author: introfog

pdfa/src/main/java/com/itextpdf/pdfa/checker/PdfAChecker.java

@@ -34,17 +34,16 @@ This file is part of the iText (R) project.
 import com.itextpdf.kernel.pdf.PdfName;
 import com.itextpdf.kernel.pdf.PdfNumber;
 import com.itextpdf.kernel.pdf.PdfObject;
+import com.itextpdf.kernel.pdf.PdfOutline;
 import com.itextpdf.kernel.pdf.PdfPage;
 import com.itextpdf.kernel.pdf.PdfStream;
 import com.itextpdf.kernel.pdf.PdfString;
 import com.itextpdf.kernel.pdf.PdfXrefTable;
 import com.itextpdf.kernel.pdf.canvas.CanvasGraphicsState;
 import com.itextpdf.kernel.pdf.colorspace.PdfColorSpace;
 
-import java.util.ArrayList;
 import java.util.HashMap;
 import java.util.HashSet;
-import java.util.List;
 import java.util.Map;
 import java.util.Set;
 
@@ -164,7 +163,9 @@ public void checkDocument(PdfCatalog catalog) {
         checkCatalog(catalog);
         checkLogicalStructure(catalogDict);
         checkForm(catalogDict.getAsDictionary(PdfName.AcroForm));
-        checkOutlines(catalogDict);
+        if (catalog.getDocument().hasOutlines()) {
+            checkOutlines(catalog.getDocument().getOutlines(false));
+        }
         checkPages(catalog.getDocument());
         checkOpenAction(catalogDict.get(PdfName.OpenAction));
         checkColorsUsages();
@@ -917,34 +918,18 @@ private void checkAnnotations(PdfDictionary page) {
         }
     }
 
-    private void checkOutlines(PdfDictionary catalogDict){
-        PdfDictionary outlines = catalogDict.getAsDictionary(PdfName.Outlines);
-        if (outlines != null) {
-            for (PdfDictionary outline : getOutlines(outlines)) {
-                PdfDictionary action = outline.getAsDictionary(PdfName.A);
-                if (action != null) {
-                    checkAction(action);
-                }
+    private void checkOutlines(PdfOutline outline){
+        if (outline != null) {
+            final PdfDictionary action = outline.getContent().getAsDictionary(PdfName.A);
+            if (action != null) {
+                checkAction(action);
+            }
+            for (PdfOutline child : outline.getAllChildren()) {
+                checkOutlines(child);
             }
         }
     }
 
-    private List<PdfDictionary> getOutlines(PdfDictionary item) {
-        List<PdfDictionary> outlines = new ArrayList<>();
-        outlines.add(item);
-
-        PdfDictionary processItem = item.getAsDictionary(PdfName.First);
-        if (processItem != null){
-            outlines.addAll(getOutlines(processItem));
-        }
-        processItem = item.getAsDictionary(PdfName.Next);
-        if (processItem != null){
-            outlines.addAll(getOutlines(processItem));
-        }
-
-        return outlines;
-    }
-
     private void setCheckerOutputIntent(PdfDictionary outputIntent) {
         if (outputIntent != null) {
             pdfAOutputIntentDestProfile = outputIntent.getAsStream(PdfName.DestOutputProfile);

pdfa/src/test/java/com/itextpdf/pdfa/checker/PdfACheckerTest.java

@@ -45,6 +45,7 @@ This file is part of the iText (R) project.
 import com.itextpdf.kernel.pdf.canvas.CanvasGraphicsState;
 import com.itextpdf.kernel.pdf.colorspace.PdfColorSpace;
 import com.itextpdf.pdfa.PdfADocument;
+import com.itextpdf.test.AssertUtil;
 import com.itextpdf.test.ExtendedITextTest;
 import com.itextpdf.test.annotations.type.UnitTest;
 
@@ -69,6 +70,13 @@ public void before() {
         pdfAChecker.setFullCheckMode(true);
     }
 
+    @Test
+    public void checkPdfWithHugeAmountOfOutlinesTest() throws IOException {
+        try(PdfDocument pdf = new PdfDocument(new PdfReader(SOURCE_FOLDER + "outlineStackOverflowTest01.pdf"))) {
+            AssertUtil.doesNotThrow(() -> pdfAChecker.checkDocument(pdf.getCatalog()));
+        }
+    }
+
     @Test
     public void checkAppearanceStreamsWithCycle() throws IOException {
         try (ByteArrayOutputStream bos = new ByteArrayOutputStream();