[gnome-remote-desktop] session-rdp: Fix check when creation of virtual channel manager fails

[Jonas Ådahl <jadahl src gnome org>]

commit dbfc75af85cdb9b0d44383b009f3a12b73961155
Author: Pascal Nowack <Pascal Nowack gmx de>
Date:   Fri Sep 9 10:12:47 2022 +0200

    session-rdp: Fix check when creation of virtual channel manager fails
    
    WTSOpenServerA() returns INVALID_HANDLE_VALUE, which is not NULL, when
    the creation of the virtual channel manager fails.
    Since NULL is an invalid value here too, check against that value too.
    This is what the sample server implementations in FreeRDP also do.
    
    Fixes: https://errors.ubuntu.com/problem/4b04e96f4f5f92ed74e814927dadeab1fba5fbdd

 src/grd-session-rdp.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)
---
diff --git a/src/grd-session-rdp.c b/src/grd-session-rdp.c
index 891c95e3..674ce333 100644
--- a/src/grd-session-rdp.c
+++ b/src/grd-session-rdp.c
@@ -1967,9 +1967,9 @@ rdp_peer_context_new (freerdp_peer   *peer,
   rdp_peer_context->planar_flags |= PLANAR_FORMAT_HEADER_RLE;
 
   rdp_peer_context->vcm = WTSOpenServerA ((LPSTR) peer->context);
-  if (!rdp_peer_context->vcm)
+  if (!rdp_peer_context->vcm || rdp_peer_context->vcm == INVALID_HANDLE_VALUE)
     {
-      g_warning ("[RDP] Failed to retrieve VCM handle");
+      g_warning ("[RDP] Failed to create virtual channel manager");
       rdp_peer_context_free (peer, rdp_peer_context);
       return FALSE;
     }