Add range check in QPDFNumberTreeObjectHelper (fuzz issue 37740)

Jay Berkenbilt
1 parent ec09b914
Showing 3 changed files with 4 additions and 0 deletions
ChangeLog
fuzz/qpdf_extra/37740.fuzz
libqpdf/QPDFNumberTreeObjectHelper.cc
 2021-11-04  Jay Berkenbilt  <ejb@ql.org>
  
+	* Add range check in QPDFNumberTreeObjectHelper (fuzz issue 37740).
+
 	* Add QIntC::range_check_substract to do range checking on
 	subtraction, which has different boundary conditions from
 	addition.
 #include <qpdf/QPDFNumberTreeObjectHelper.hh>
 #include <qpdf/NNTree.hh>
+#include <qpdf/QIntC.hh>
  
 class NumberTreeDetails: public NNTreeDetails
 {
@@ -235,6 +236,7 @@ QPDFNumberTreeObjectHelper::findObjectAtOrBelow(
         return false;
     }
     oh = i->second;
+    QIntC::range_check_substract(idx, i->first);
     offset = idx - i->first;
     return true;
 }