Verify image dimentions before using

core/fpdfapi/fpdf_render/fpdf_render_image.cpp

 // Copyright 2014 PDFium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 // Original code copyright 2014 Foxit Software Inc. http://www.foxitsoftware.com
 
 #include "core/fpdfapi/fpdf_render/render_int.h"
 
 #include <memory>
 #include <utility>
@@ skipping 348 matching lines @@
 
 CPDF_ImageRenderer::~CPDF_ImageRenderer() {
   if (m_DeviceHandle) {
     m_pRenderStatus->m_pDevice->CancelDIBits(m_DeviceHandle);
   }
 }
 
 FX_BOOL CPDF_ImageRenderer::StartLoadDIBSource() {
   CFX_FloatRect image_rect_f = m_ImageMatrix.GetUnitRect();
   FX_RECT image_rect = image_rect_f.GetOuterRect();
+  if (!image_rect.Valid())
+    return FALSE;
+
   int dest_width = image_rect.Width();
   int dest_height = image_rect.Height();
   if (m_ImageMatrix.a < 0) {
     dest_width = -dest_width;
   }
   if (m_ImageMatrix.d > 0) {
     dest_height = -dest_height;
   }
   if (m_Loader.Start(m_pImageObject,
                      m_pRenderStatus->m_pContext->GetPageCache(), &m_LoadHandle,
@@ skipping 688 matching lines @@
   } else if (pFunc) {
     int size = dest_pitch * height;
     for (int i = 0; i < size; i++) {
       dest_buf[i] = transfers[src_buf[i]];
     }
   } else {
     FXSYS_memcpy(dest_buf, src_buf, dest_pitch * height);
   }
   return pMask.release();
 }