Load external references in encrypted emails only on explicit request.

Taken from KDE patches and adapted to TDE.
See https://phabricator.kde.org/D12391

Signed-off-by: Slávek Banko <slavek.banko@axis.cz>

kmail/kmreaderwin.cpp

@@ -1408,8 +1408,6 @@ void KMReaderWin::updateReaderWin()
 {
   if (!mMsgDisplay) return;
 
-  mViewer->setOnlyLocalReferences(!htmlLoadExternal());
-
   htmlWriter()->reset();
 
   KMFolder* folder = 0;
@@ -1579,6 +1577,7 @@ void KMReaderWin::parseMsg(KMMessage* aMsg)
   //  - this can only be done *after* calling parseObjectTree()
   KMMsgEncryptionState encryptionState = mRootNode->overallEncryptionState();
   KMMsgSignatureState  signatureState  = mRootNode->overallSignatureState();
+  mViewer->setOnlyLocalReferences(!htmlLoadExternal());
   // Don't crash when switching message while GPG passphrase entry dialog is shown #53185
   if (aMsg != message()) {
     displayMessage();
@@ -2515,6 +2514,17 @@ bool KMReaderWin::htmlMail()
 //-----------------------------------------------------------------------------
 bool KMReaderWin::htmlLoadExternal()
 {
+	if (!mRootNode)
+	{
+		return mHtmlLoadExtOverride;
+	}
+
+	// when displaying an encrypted message, only load external resources on explicit request
+	if (mRootNode->overallEncryptionState() != KMMsgNotEncrypted)
+	{
+		return mHtmlLoadExtOverride;
+	}
+
 	return ((mHtmlLoadExternal && !mHtmlLoadExtOverride) ||
 	        (!mHtmlLoadExternal && mHtmlLoadExtOverride));
 }