From 62401ba3c9df1f7234bd272b3e659a08f546d50c Mon Sep 17 00:00:00 2001
From: Miklos Vajna <vmiklos@collabora.co.uk>
Date: Tue, 8 Nov 2016 15:54:15 +0100
Subject: [PATCH] xmlsecurity PDF sign: don't crash on missing trailer

This will need cross-reference stream write support, just don't crash
for now.

Change-Id: Id48c131b22d4ed96174693f3e96b14c273d596a8
Reviewed-on: https://gerrit.libreoffice.org/30702
Tested-by: Jenkins <ci@libreoffice.org>
Reviewed-by: Miklos Vajna <vmiklos@collabora.co.uk>
---
 xmlsecurity/source/pdfio/pdfdocument.cxx | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/xmlsecurity/source/pdfio/pdfdocument.cxx b/xmlsecurity/source/pdfio/pdfdocument.cxx
index 0bc2f80d6798..cd52f8d0eaac 100644
--- a/xmlsecurity/source/pdfio/pdfdocument.cxx
+++ b/xmlsecurity/source/pdfio/pdfdocument.cxx
@@ -478,6 +478,11 @@ bool PDFDocument::Sign(const uno::Reference<security::XCertificate>& xCertificat
     m_aEditBuffer.WriteCharPtr("\nendobj\n\n");
 
     // Write the updated Catalog object, references nAnnotId.
+    if (!m_pTrailer)
+    {
+        SAL_WARN("xmlsecurity.pdfio", "PDFDocument::Sign: found no trailer");
+        return false;
+    }
     auto pRoot = dynamic_cast<PDFReferenceElement*>(m_pTrailer->Lookup("Root"));
     if (!pRoot)
     {