From 4b4831be07249743364a7335178fb44b4b3eeca7 Mon Sep 17 00:00:00 2001
From: Roland Haeder <roland@mxchange.org>
Date: Wed, 16 Nov 2016 14:17:43 +0100
Subject: [PATCH] Catch some invalid parameter (may come from damaged file) and
 throw exception. (#39)
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Signed-off-by: Roland Häder <roland@mxchange.org>
---
 src/PhpSpreadsheet/Shared/OLERead.php | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/src/PhpSpreadsheet/Shared/OLERead.php b/src/PhpSpreadsheet/Shared/OLERead.php
index 63bff33c..05f1415f 100644
--- a/src/PhpSpreadsheet/Shared/OLERead.php
+++ b/src/PhpSpreadsheet/Shared/OLERead.php
@@ -302,6 +302,14 @@ class OLERead
      */
     private static function getInt4d($data, $pos)
     {
+        if (trim($data) == '') {
+            // No data provided
+            throw new \PhpOffice\PhpSpreadsheet\Reader\Exception('Parameter data is empty.');
+        } elseif ($pos < 0) {
+            // Invalid position
+            throw new \PhpOffice\PhpSpreadsheet\Reader\Exception('Parameter pos=' . $pos . ' is invalid.');
+        }
+
         $len = strlen($data);
         if ($len < $pos + 4) {
             $data .= str_repeat("\0", $pos + 4 - $len);