Verify value of prec before using

core/fxcodec/codec/fx_codec_jpx_opj.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 <algorithm>
 #include <limits>
 #include <vector>
 
@@ skipping 213 matching lines @@
           (img->comps[0].h + 1) / 2 == img->comps[1].h);
 }
 static bool sycc422_size_is_valid(opj_image_t* img) {
   return (sycc420_422_size_is_valid(img) && img->comps[0].h == img->comps[1].h);
 }
 static void sycc422_to_rgb(opj_image_t* img) {
   if (!sycc422_size_is_valid(img))
     return;
 
   int prec = img->comps[0].prec;
+  if (prec <= 0 || prec >= 32)
+    return;
+
   int offset = 1 << (prec - 1);
   int upb = (1 << prec) - 1;
 
   OPJ_UINT32 maxw = img->comps[0].w;
   OPJ_UINT32 maxh = img->comps[0].h;
   FX_SAFE_SIZE_T max_size = maxw;
   max_size *= maxh;
   if (!max_size.IsValid())
     return;
 
@@ skipping 656 matching lines @@
 bool CCodec_JpxModule::Decode(CJPX_Decoder* pDecoder,
                               uint8_t* dest_data,
                               int pitch,
                               const std::vector<uint8_t>& offsets) {
   return pDecoder->Decode(dest_data, pitch, offsets);
 }
 
 void CCodec_JpxModule::DestroyDecoder(CJPX_Decoder* pDecoder) {
   delete pDecoder;
 }