xmlsecurity: fix crash in DocumentDigitalSignatures::isAuthorTrusted()

If the argument is null.

This function also should use EqualDistinguishedNames().

Change-Id: I4068aa94f9d9c422c96b394c82d3e28303774b0b
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/111667
Tested-by: Jenkins
Reviewed-by: Michael Stahl <michael.stahl@allotropia.de>

1 files changed, 8 insertions, 4 deletions

diff --git a/xmlsecurity/source/component/documentdigitalsignatures.cxx b/xmlsecurity/source/component/documentdigitalsignatures.cxx
index f3b74de8f752..6dfb9799190d 100644
--- a/xmlsecurity/source/component/documentdigitalsignatures.cxx
+++ b/xmlsecurity/source/component/documentdigitalsignatures.cxx
@@ -655,15 +655,19 @@ void DocumentDigitalSignatures::showCertificate(
 }
 
 sal_Bool DocumentDigitalSignatures::isAuthorTrusted(
-    const Reference< css::security::XCertificate >& Author )
+    const Reference<css::security::XCertificate>& xAuthor)
 {
-    OUString sSerialNum = xmlsecurity::bigIntegerToNumericString( Author->getSerialNumber() );
+    if (!xAuthor.is())
+    {
+        return false;
+    }
+    OUString sSerialNum = xmlsecurity::bigIntegerToNumericString(xAuthor->getSerialNumber());
 
     std::vector< SvtSecurityOptions::Certificate > aTrustedAuthors = SvtSecurityOptions().GetTrustedAuthors();
 
     return std::any_of(aTrustedAuthors.begin(), aTrustedAuthors.end(),
-        [&Author, &sSerialNum](const SvtSecurityOptions::Certificate& rAuthor) {
-            return ( rAuthor.SubjectName == Author->getIssuerName() )
+        [&xAuthor, &sSerialNum](const SvtSecurityOptions::Certificate& rAuthor) {
+            return xmlsecurity::EqualDistinguishedNames(rAuthor.SubjectName, xAuthor->getIssuerName())
                 && ( rAuthor.SerialNumber == sSerialNum );
         });
 }