vtkXMLTreeReader: protect against possible nullptr dereference

Origin: upstream,https://gitlab.kitware.com/vtk/vtk/-/commit/72119ea71422d2892f2a0475fc282835310f8d9e
Forwarded: not-needed
Bug-Debian: https://bugs.debian.org/1031877

Vulnerability reported at
https://nvd.nist.gov/vuln/detail/CVE-2021-42521.

Gbp-Pq: Name 08_CVE-2021-42521.patch

diff --git a/IO/Infovis/vtkXMLTreeReader.cxx b/IO/Infovis/vtkXMLTreeReader.cxx
index 02876f00cdefbe1093b6966b21cef5f20bb10336..946c7b9f272f3ad0574030fdc0d4cdf4bec65828 100644 (file)
--- a/IO/Infovis/vtkXMLTreeReader.cxx
+++ b/IO/Infovis/vtkXMLTreeReader.cxx
@@ -217,6 +217,12 @@ int vtkXMLTreeReader::RequestData(
 
   // Get the root element node
   xmlNode* rootElement = xmlDocGetRootElement(doc);
+  if (!rootElement)
+  {
+    vtkErrorMacro(<< "Could not get root element of document.");
+    return 0;
+  }
+
   vtkXMLTreeReaderProcessElement(builder, -1, rootElement, this->ReadCharData, this->MaskArrays);
 
   xmlFreeDoc(doc);