Bounds check before fixed-size memcmp() in CJPX_Decoder::Init().

core/src/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 "../../../include/fxcodec/fx_codec.h"
 #include "codec_int.h"
 #include "../fx_libopenjpeg/libopenjpeg20/openjpeg.h"
 #include "../lcms2/include/fx_lcms2.h"
@@ skipping 563 matching lines @@
     }
     if(l_stream) {
         opj_stream_destroy(l_stream);
     }
     if(image) {
         opj_image_destroy(image);
     }
 }
 FX_BOOL CJPX_Decoder::Init(const unsigned char* src_data, int src_size)
 {
     opj_dparameters_t parameters;

[jun_fang, 2014/08/26 21:48:09]

if (!src_data || src_size <= 0) {
    return FALSE;
}

[jun_fang, 2014/08/26 22:01:17]

We can define an array to save the string
"\x00\x00\x00\x0c\x6a\x50\x20\x20\x0d\x0a\x87\x0a" here and check:

char szJP2Header[] = {'\x00','\x00',
'\x00','\x0c','\x6a','\x50','\x20','\x20','\x0d','\x0a','\x87','\x0a'};

if (!src_data || src_size <= sizeof(szJP2Header)/sizeof(char)) {
    return FALSE;
}

     image = NULL;
     m_SrcData = src_data;
     m_SrcSize = src_size;
     decodeData srcData;
     srcData.offset  = 0;
     srcData.src_size = src_size;
     srcData.src_data = src_data;
     l_stream = fx_opj_stream_create_memory_stream(&srcData, OPJ_J2K_STREAM_CHUNK_SIZE, 1);
     if (l_stream == NULL) {
         return FALSE;
     }
     opj_set_default_decoder_parameters(&parameters);
     parameters.decod_format = 0;
     parameters.cod_format = 3;
-    if(FXSYS_memcmp32(m_SrcData, "\x00\x00\x00\x0c\x6a\x50\x20\x20\x0d\x0a\x87\x0a", 12) == 0) {
+    if(m_SrcSize >= 12 && FXSYS_memcmp32(m_SrcData, "\x00\x00\x00\x0c\x6a\x50\x20\x20\x0d\x0a\x87\x0a", 12) == 0) {

[jun_fang, 2014/08/26 21:48:09]

1. Define an array to save the string "\x00\x00\x00\x0c\x6a\x50\x2
     0\x20\x0d\x0a\x87\x0a". This array's name can be szJP2Header.
2. Use sizeof(arrary_name) to replace '12' that is a magic number.

         l_codec = opj_create_decompress(OPJ_CODEC_JP2);
         parameters.decod_format = 1;
     } else {
         l_codec = opj_create_decompress(OPJ_CODEC_J2K);
     }
     if(!l_codec) {
         return FALSE;
     }
     opj_set_info_handler(l_codec, fx_info_callback, 00);
     opj_set_warning_handler(l_codec, fx_warning_callback, 00);
@@ skipping 172 matching lines @@
 FX_BOOL CCodec_JpxModule::Decode(void* ctx, FX_LPBYTE dest_data, int pitch, FX_BOOL bTranslateColor, FX_LPBYTE offsets)
 {
     CJPX_Decoder* pDecoder = (CJPX_Decoder*)ctx;
     return pDecoder->Decode(dest_data, pitch, bTranslateColor, offsets);
 }
 void CCodec_JpxModule::DestroyDecoder(void* ctx)
 {
     CJPX_Decoder* pDecoder = (CJPX_Decoder*)ctx;
     delete pDecoder;
 }