Don't crash when accessing WebDAV resource after auth failed

In my testing on Windows, the crashing scenario was this:
1. FileDialogHelper_Impl::updateVersions() creates storage calling
   comphelper::OStorageHelper::GetStorageFromURL;
2. Content::openStream() calls isDocument first;
3. Content::isDocument() indirectly initiates WebDAV session,
   creating a NeonSession;
4. All operations of NeonSession call Init() first; its first call
   initializes m_pHttpSession using ne_session_create, and then
   adds auth callbacks using ne_add_server_auth/ne_add_proxy_auth
5. Then NeonSession performs the rest of PROPFIND task, calling
   ah_post_send and auth_challenge; the latter fails, then
   ah_post_send calls clean_session, which cleans m_pHttpSession's
   auth_session's sspi_host;
6. NeonSession::HandleError throws DAVException for NE_AUTH error;
7. Content::isDocument() returns true to Content::openStream(),
   which proceeds to execute the command, which in turn re-uses
   the NeonSession and its m_pHttpSession;
8. NeonSession::OPTIONS then indirectly calls continue_sspi, which
   tries to dereference the m_pHttpSession's auth_session's
   sspi_host which is nullptr at this point.

So in case NeonSession detects the NE_AUTH error condition, let's
set a flag indicating that the next Init() should reinitialize its
m_pHttpSession.

Also fixed a case when xProps was used before initialization in
Content::getPropertyValues.

Change-Id: Ifc9eec4fe0333ff6be17c5089068441b4a6eb78c
Reviewed-on: https://gerrit.libreoffice.org/65950
Tested-by: Jenkins
Reviewed-by: Mike Kaganski <mike.kaganski@collabora.com>

ucb/source/ucp/webdav-neon/NeonSession.cxx

@@ -671,7 +671,8 @@ void NeonSession::Init()
 {
     osl::Guard< osl::Mutex > theGuard( m_aMutex );
 
-    bool bCreateNewSession = false;
+    bool bCreateNewSession = m_bNeedNewSession;
+    m_bNeedNewSession = false;
 
     if ( m_pHttpSession == nullptr )
     {
@@ -725,13 +726,17 @@ void NeonSession::Init()
             m_aProxyName = rProxyCfg.aName;
             m_nProxyPort = rProxyCfg.nPort;
 
+            bCreateNewSession = true;
+        }
+
+        if (bCreateNewSession)
+        {
             // new session needed, destroy old first
             {
                 osl::Guard< osl::Mutex > theGlobalGuard(getGlobalNeonMutex());
                 ne_session_destroy( m_pHttpSession );
             }
             m_pHttpSession = nullptr;
-            bCreateNewSession = true;
         }
     }
 
@@ -1966,6 +1971,11 @@ void NeonSession::HandleError( int nError,
                                     m_aHostName, m_nPort ) );
 
         case NE_AUTH:         // User authentication failed on server
+            // m_pHttpSession could get invalidated, e.g., as result of clean_session called in
+            // ah_post_send in case when auth_challenge failed, which invalidates the auth_session
+            // which we established in Init(): the auth_session's sspi_host gets disposed, and
+            // next attempt to authenticate would crash in continue_sspi trying to dereference it
+            m_bNeedNewSession = true;
             throw DAVException( DAVException::DAV_HTTP_AUTH,
                                 NeonUri::makeConnectionEndPointString(
                                     m_aHostName, m_nPort ) );

ucb/source/ucp/webdav-neon/NeonSession.hxx

@@ -54,6 +54,7 @@ private:
     sal_Int32         m_nProxyPort;
     css::uno::Sequence< css::beans::NamedValue > const m_aFlags;
     HttpSession *     m_pHttpSession;
+    bool m_bNeedNewSession = false; // Something happened that could invalidate m_pHttpSession
     void * const      m_pRequestData;
     const ucbhelper::InternetProxyDecider & m_rProxyDecider;
 

ucb/source/ucp/webdav-neon/webdavcontent.cxx

@@ -1586,12 +1586,10 @@ uno::Reference< sdbc::XRow > Content::getPropertyValues(
 
         if ( eType == DAV )
         {
-            //xProps.reset(
-            //    new ContentProperties( aUnescapedTitle ) );
-            xProps->addProperty(
-                "Title",
-                uno::makeAny( aUnescapedTitle ),
-                true );
+            if (!xProps)
+                xProps.reset(new ContentProperties(aUnescapedTitle));
+            else
+                xProps->addProperty("Title", uno::makeAny(aUnescapedTitle), true);
         }
         else
         {