Ensure that ChunkedStream won't attempt to request data *beyond* the document size (issue 14303)

This bug was surprisingly difficult to track down, since it didn't just depend on range-requests being used but also on how quickly the document was loaded. To even be able to reproduce this locally, I had to use a very small `rangeChunkSize`-value (note the unit-test).

The cause of this bug is a bogus entry in the XRef-table, causing us to attempt to request data from *beyond* the actual document size and thus getting into an infinite loop.

Fixes *one* of the issues listed in issue 14303, namely the `PDFBOX-4352-0.pdf` document.

src/core/chunked_stream.js

@@ -107,6 +107,9 @@ class ChunkedStream extends Stream {
     }
 
     const chunk = Math.floor(pos / this.chunkSize);
+    if (chunk > this.numChunks) {
+      return;
+    }
     if (chunk === this.lastSuccessfulEnsureByteChunk) {
       return;
     }
@@ -125,9 +128,14 @@ class ChunkedStream extends Stream {
       return;
     }
 
-    const chunkSize = this.chunkSize;
-    const beginChunk = Math.floor(begin / chunkSize);
-    const endChunk = Math.floor((end - 1) / chunkSize) + 1;
+    const beginChunk = Math.floor(begin / this.chunkSize);
+    if (beginChunk > this.numChunks) {
+      return;
+    }
+    const endChunk = Math.min(
+      Math.floor((end - 1) / this.chunkSize) + 1,
+      this.numChunks
+    );
     for (let chunk = beginChunk; chunk < endChunk; ++chunk) {
       if (!this._loadedChunks.has(chunk)) {
         throw new MissingDataException(begin, end);

test/pdfs/.gitignore

@@ -487,3 +487,4 @@
 !secHandler.pdf
 !rc_annotation.pdf
 !issue14267.pdf
+!PDFBOX-4352-0.pdf

test/unit/api_spec.js

@@ -443,6 +443,21 @@ describe("api", function () {
 
       await Promise.all([loadingTask1.destroy(), loadingTask2.destroy()]);
     });
+
+    it("creates pdf doc from PDF file with bad XRef table", async function () {
+      // A corrupt PDF file, where the XRef table have (some) bogus entries.
+      const loadingTask = getDocument(
+        buildGetDocumentParams("PDFBOX-4352-0.pdf", {
+          rangeChunkSize: 100,
+        })
+      );
+      expect(loadingTask instanceof PDFDocumentLoadingTask).toEqual(true);
+
+      const pdfDocument = await loadingTask.promise;
+      expect(pdfDocument.numPages).toEqual(1);
+
+      await loadingTask.destroy();
+    });
   });
 
   describe("PDFWorker", function () {