Fixed missing argument checks.

diff --git a/libfreerdp/cache/offscreen.c b/libfreerdp/cache/offscreen.c
index dacc1d9..1b7c2b0 100644 (file)
--- a/libfreerdp/cache/offscreen.c
+++ b/libfreerdp/cache/offscreen.c
@@ -44,7 +44,12 @@ static BOOL update_gdi_create_offscreen_bitmap(rdpContext* context,
        UINT32 i;
        UINT16 index;
        rdpBitmap* bitmap;
-       rdpCache* cache = context->cache;
+       rdpCache* cache;
+
+       if (!context || !createOffscreenBitmap || !context->cache)
+               return FALSE;
+
+       cache = context->cache;
        bitmap = Bitmap_Alloc(context);
 
        if (!bitmap)
@@ -77,8 +82,16 @@ static BOOL update_gdi_create_offscreen_bitmap(rdpContext* context,
 static BOOL update_gdi_switch_surface(rdpContext* context,
                                       const SWITCH_SURFACE_ORDER* switchSurface)
 {
-       rdpCache* cache = context->cache;
-       rdpBitmap* bitmap = context->graphics->Bitmap_Prototype;
+       rdpCache* cache;
+       rdpBitmap* bitmap;
+
+       if (!context || !context->cache || !switchSurface || !context->graphics)
+               return FALSE;
+
+       cache = context->cache;
+       bitmap = context->graphics->Bitmap_Prototype;
+       if (!bitmap)
+               return FALSE;
 
        if (switchSurface->bitmapId == SCREEN_BITMAP_SURFACE)
        {