Fix infinite loop caused by parsing same indirect objects

core/src/fpdfapi/fpdf_parser/fpdf_parser_parser.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/include/fpdfapi/fpdf_parser.h"
 
 #include <algorithm>
 #include <memory>
@@ skipping 1173 matching lines @@
   m_Syntax.RestorePos(SavedPos);
   return TRUE;
 }
 
 CPDF_Object* CPDF_Parser::ParseIndirectObject(CPDF_IndirectObjects* pObjList,
                                               FX_DWORD objnum,
                                               PARSE_CONTEXT* pContext) {
   if (!IsValidObjectNumber(objnum))
     return nullptr;
 
+  // Prevent circular parsing the same object.
+  if (pdfium::ContainsKey(objnums_in_processing, objnum))
+    return nullptr;
+  ScopedSetInsertion<FX_DWORD> local_insert(&objnums_in_processing, objnum);
+
   if (m_V5Type[objnum] == 1 || m_V5Type[objnum] == 255) {
     FX_FILESIZE pos = m_ObjectInfo[objnum].pos;
     if (pos <= 0)
       return nullptr;
     return ParseIndirectObjectAt(pObjList, pos, objnum, pContext);
   }
   if (m_V5Type[objnum] != 2)
     return nullptr;
 
   CPDF_StreamAcc* pObjStream = GetObjectStream(m_ObjectInfo[objnum].pos);
@@ skipping 3765 matching lines @@
   if (!m_pLinearizedDict)
     return -1;
   CPDF_Array* pRange = m_pLinearizedDict->GetArray("H");
   if (!pRange)
     return -1;
   CPDF_Object* pStreamLen = pRange->GetElementValue(1);
   if (!pStreamLen)
     return -1;
   return pStreamLen->GetInteger();
 }