forcepoint#67 detect cairo surface creation failure

if e.g. too large

Change-Id: I7de8748a5ed695c1b3ddc8c1358414f3acd68c94
Reviewed-on: https://gerrit.libreoffice.org/58453
Tested-by: Jenkins
Reviewed-by: Caolán McNamara <caolanm@redhat.com>
Tested-by: Caolán McNamara <caolanm@redhat.com>

vcl/headless/svpgdi.cxx

@@ -1264,6 +1264,11 @@ void SvpSalGraphics::drawMask( const SalTwoRect& rTR,
     /** creates an image from the given rectangle, replacing all black pixels
      *  with nMaskColor and make all other full transparent */
     SourceHelper aSurface(rSalBitmap, true); // The mask is argb32
+    if (!aSurface.getSurface())
+    {
+        SAL_WARN("vcl.gdi", "unsupported SvpSalGraphics::drawMask case");
+        return;
+    }
     sal_Int32 nStride;
     unsigned char *mask_data = aSurface.getBits(nStride);
     for (sal_Int32 y = rTR.mnSrcY ; y < rTR.mnSrcY + rTR.mnSrcHeight; ++y)
@@ -1517,6 +1522,11 @@ cairo_surface_t* SvpSalGraphics::createCairoSurface(const BitmapBuffer *pBuffer)
                                         nFormat,
                                         pBuffer->mnWidth, pBuffer->mnHeight,
                                         pBuffer->mnScanlineSize);
+    if (cairo_surface_status(target) != CAIRO_STATUS_SUCCESS)
+    {
+        cairo_surface_destroy(target);
+        return nullptr;
+    }
     return target;
 }