Handle errors correctly when data lookup fails during /Pages-tree parsing (issue 14303)

This only applies to severely corrupt documents, where it's possible that the `Parser` throws when we try to access e.g. a /Kids-entry in the /Pages-tree.

Fixes two of the issues listed in issue 14303, namely the `poppler-742-0.pdf...` and `poppler-937-0.pdf...` documents.

src/core/catalog.js

@@ -1091,15 +1091,14 @@ class Catalog {
     const visitedNodes = new RefSet();
     const xref = this.xref,
       pageKidsCountCache = this.pageKidsCountCache;
-    let count,
+    let currentPageIndex = 0;
-      currentPageIndex = 0;
 
     function next() {
       while (nodesToVisit.length) {
         const currentNode = nodesToVisit.pop();
 
         if (isRef(currentNode)) {
-          count = pageKidsCountCache.get(currentNode);
+          const count = pageKidsCountCache.get(currentNode);
           // Skip nodes where the page can't be.
           if (count > 0 && currentPageIndex + count < pageIndex) {
             currentPageIndex += count;
@@ -1146,7 +1145,14 @@ class Catalog {
           return;
         }
 
-        count = currentNode.get("Count");
+        let count;
+        try {
+          count = currentNode.get("Count");
+        } catch (ex) {
+          if (ex instanceof MissingDataException) {
+            throw ex;
+          }
+        }
         if (Number.isInteger(count) && count >= 0 && !skipCount) {
           // Cache the Kids count, since it can reduce redundant lookups in
           // documents where all nodes are found at *one* level of the tree.
@@ -1161,13 +1167,28 @@ class Catalog {
           }
         }
 
-        const kids = currentNode.get("Kids");
+        let kids;
+        try {
+          kids = currentNode.get("Kids");
+        } catch (ex) {
+          if (ex instanceof MissingDataException) {
+            throw ex;
+          }
+        }
         if (!Array.isArray(kids)) {
           // Prevent errors in corrupt PDF documents that violate the
           // specification by *inlining* Page dicts directly in the Kids
           // array, rather than using indirect objects (fixes issue9540.pdf).
+          let type;
+          try {
+            type = currentNode.get("Type");
+          } catch (ex) {
+            if (ex instanceof MissingDataException) {
+              throw ex;
+            }
+          }
           if (
-            isName(currentNode.get("Type"), "Page") ||
+            isName(type, "Page") ||
             (!currentNode.has("Type") && currentNode.has("Contents"))
           ) {
             if (currentPageIndex === pageIndex) {

test/pdfs/.gitignore

@@ -494,3 +494,5 @@
 !poppler-85140-0.pdf
 !poppler-91414-0-53.pdf
 !poppler-91414-0-54.pdf
+!poppler-742-0-fuzzed.pdf
+!poppler-937-0-fuzzed.pdf

test/unit/api_spec.js

@@ -545,6 +545,48 @@ describe("api", function () {
 
       await Promise.all([loadingTask1.destroy(), loadingTask2.destroy()]);
     });
+
+    it("creates pdf doc from PDF files, with bad /Pages tree /Kids entries", async function () {
+      const loadingTask1 = getDocument(
+        buildGetDocumentParams("poppler-742-0-fuzzed.pdf")
+      );
+      const loadingTask2 = getDocument(
+        buildGetDocumentParams("poppler-937-0-fuzzed.pdf")
+      );
+      expect(loadingTask1 instanceof PDFDocumentLoadingTask).toEqual(true);
+      expect(loadingTask2 instanceof PDFDocumentLoadingTask).toEqual(true);
+
+      const pdfDocument1 = await loadingTask1.promise;
+      const pdfDocument2 = await loadingTask2.promise;
+
+      expect(pdfDocument1.numPages).toEqual(1);
+      expect(pdfDocument2.numPages).toEqual(1);
+
+      try {
+        await pdfDocument1.getPage(1);
+
+        // Shouldn't get here.
+        expect(false).toEqual(true);
+      } catch (reason) {
+        expect(reason instanceof UnknownErrorException).toEqual(true);
+        expect(reason.message).toEqual(
+          "Page dictionary kids object is not an array."
+        );
+      }
+      try {
+        await pdfDocument2.getPage(1);
+
+        // Shouldn't get here.
+        expect(false).toEqual(true);
+      } catch (reason) {
+        expect(reason instanceof UnknownErrorException).toEqual(true);
+        expect(reason.message).toEqual(
+          "Page dictionary kids object is not an array."
+        );
+      }
+
+      await Promise.all([loadingTask1.destroy(), loadingTask2.destroy()]);
+    });
   });
 
   describe("PDFWorker", function () {