Add additional sanity check during xref reconstruction

Check that xref table is not empty after recovery. Empty xref tables disable other sanity checks.

Add additional sanity check during xref reconstruction
Check that xref table is not empty after recovery. Empty xref tables disable other sanity checks.
m-holger
1 parent 7445e0ac
Showing 2 changed files with 6 additions and 1 deletions
libqpdf/QPDF.cc
qpdf/qtest/qpdf/issue-147.out
@@ -641,6 +641,11 @@ QPDF::reconstruct_xref(QPDFExc&amp; e)
         throw damagedPDF("", 0, "unable to find trailer dictionary while recovering damaged file");
     }
+    if (m->xref_table.empty()) {
+        // We cannot check for an empty xref table in parse because empty tables are valid when
+        // creating QPDF objects from JSON.
+        throw damagedPDF("", 0, "unable to find objects while recovering damaged file");
+    }
     // We could iterate through the objects looking for streams and try to find objects inside of
     // them, but it's probably not worth the trouble.  Acrobat can't recover files with any errors
@@ -4,4 +4,4 @@ WARNING: issue-147.pdf: can&#39;t find startxref
 WARNING: issue-147.pdf: Attempting to reconstruct cross-reference table
 WARNING: issue-147.pdf (trailer, offset 9): expected dictionary key but found non-name object; inserting key /QPDFFake1
 WARNING: issue-147.pdf: ignoring object with impossibly large id 62
-qpdf: issue-147.pdf: unable to find /Root dictionary
+qpdf: issue-147.pdf: unable to find objects while recovering damaged file