XFA: Fix SEGV in CPDFXFA_Document::SetCurrentPage()

fpdfsdk/src/fpdfxfa/fpdfxfa_doc.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 "fpdfsdk/include/fsdk_define.h"
 #include "fpdfsdk/include/fpdfxfa/fpdfxfa_doc.h"
 #include "fpdfsdk/include/fsdk_mgr.h"
 #include "fpdfsdk/include/fpdfxfa/fpdfxfa_app.h"
@@ skipping 524 matching lines @@
   if (m_iDocType != DOCTYPE_DYNAMIC_XFA)
     return -1;
 
   CPDFDoc_Environment* pEnv = m_pSDKDoc->GetEnv();
   if (pEnv == NULL)
     return -1;
 
   return pEnv->FFI_GetCurrentPageIndex(this);
 }
 void CPDFXFA_Document::SetCurrentPage(IXFA_Doc* hDoc, int32_t iCurPage) {
-  if (hDoc != m_pXFADoc || !m_pSDKDoc)
+  if (hDoc != m_pXFADoc || !m_pSDKDoc || m_iDocType != DOCTYPE_DYNAMIC_XFA ||
+      iCurPage < 0 || iCurPage >= m_pSDKDoc->GetPageCount()) {
     return;
-  if (m_iDocType != DOCTYPE_DYNAMIC_XFA)
+  }
+  CPDFDoc_Environment* pEnv = m_pSDKDoc->GetEnv();
+  if (!pEnv)
     return;
-
-  CPDFDoc_Environment* pEnv = m_pSDKDoc->GetEnv();
-  if (pEnv == NULL)
-    return;
-
   pEnv->FFI_SetCurrentPage(this, iCurPage);
 }
 FX_BOOL CPDFXFA_Document::IsCalculationsEnabled(IXFA_Doc* hDoc) {
   if (hDoc != m_pXFADoc || !m_pSDKDoc)
     return FALSE;
   if (m_pSDKDoc->GetInterForm())
     return m_pSDKDoc->GetInterForm()->IsXfaCalculateEnabled();
 
   return FALSE;
 }
@@ skipping 692 matching lines @@
   }
 
   return _GetHValueByName(szPropName, hValue,
                           m_pSDKDoc->GetEnv()->GetJSRuntime());
 }
 FX_BOOL CPDFXFA_Document::_GetHValueByName(const CFX_ByteStringC& utf8Name,
                                            FXJSE_HVALUE hValue,
                                            IJS_Runtime* runTime) {
   return runTime->GetHValueByName(utf8Name, hValue);
 }