Merge pull request #8170 from Snuffleupagus/issue-8169

Try to recover when encountering JPEG markers with too short marker lengths (issue 8169)

src/core/jpg.js

@@ -26,6 +26,7 @@
   }
 }(this, function (exports, sharedUtil) {
 
+var warn = sharedUtil.warn;
 var error = sharedUtil.error;
 
 /**
@@ -604,8 +605,28 @@ var JpegImage = (function JpegImageClosure() {
       }
 
       function readDataBlock() {
+        function isValidMarkerAt(pos) {
+          if (pos < data.length - 1) {
+            return (data[pos] === 0xFF &&
+                    data[pos + 1] >= 0xC0 && data[pos + 1] <= 0xFE);
+          }
+          return true;
+        }
+
         var length = readUint16();
-        var array = data.subarray(offset, offset + length - 2);
+        var endOffset = offset + length - 2;
+
+        if (!isValidMarkerAt(endOffset)) {
+          warn('readDataBlock - incorrect length, next marker is: ' +
+               (data[endOffset] << 8 | data[endOffset + 1]).toString('16'));
+          var pos = offset;
+          while (!isValidMarkerAt(pos)) {
+            pos++;
+          }
+          endOffset = pos;
+        }
+
+        var array = data.subarray(offset, endOffset);
         offset += array.length;
         return array;
       }

test/pdfs/issue8169.pdf.link

@@ -0,0 +1 @@
+http://web.archive.org/save/_embed/http://210.243.166.143/prob1.pdf

test/test_manifest.json

@@ -733,6 +733,13 @@
        "link": false,
        "type": "eq"
     },
+    {  "id": "issue8169",
+       "file": "pdfs/issue8169.pdf",
+       "md5": "62fd6479f9e1c8c5ce8cba6b1781d0a5",
+       "rounds": 1,
+       "link": true,
+       "type": "eq"
+    },
     {  "id": "txt2pdf",
        "file": "pdfs/txt2pdf.pdf",
        "md5": "02cefa0f5e8d96313bb05163b2f88c8c",