Clear decoders after the image decoder in the /Filter array

core/src/fpdfapi/fpdf_parser/fpdf_parser_decode.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 <limits.h>
 
 #include "core/include/fpdfapi/fpdf_module.h"
 #include "core/include/fpdfapi/fpdf_parser.h"
@@ skipping 345 matching lines @@
   }
   uint8_t* last_buf = (uint8_t*)src_buf;
   FX_DWORD last_size = src_size;
   for (int i = 0; i < DecoderList.GetSize(); i++) {
     int estimated_size =
         i == DecoderList.GetSize() - 1 ? last_estimated_size : 0;
     CFX_ByteString decoder = DecoderList[i];
     // Use ToDictionary here because we can push NULL into the ParamList.
     CPDF_Dictionary* pParam =
         ToDictionary(static_cast<CPDF_Object*>(ParamList[i]));
-    uint8_t* new_buf = NULL;
+    uint8_t* new_buf = nullptr;
     FX_DWORD new_size = (FX_DWORD)-1;
     int offset = -1;
     if (decoder == FX_BSTRC("FlateDecode") || decoder == FX_BSTRC("Fl")) {
       if (bImageAcc && i == DecoderList.GetSize() - 1) {
         ImageEncoding = FX_BSTRC("FlateDecode");
         dest_buf = (uint8_t*)last_buf;
         dest_size = last_size;
         pImageParms = pParam;
         return TRUE;
       }
@@ skipping 11 matching lines @@
     } else if (decoder == FX_BSTRC("RunLengthDecode") ||
                decoder == FX_BSTRC("RL")) {
       if (bImageAcc && i == DecoderList.GetSize() - 1) {
         ImageEncoding = FX_BSTRC("RunLengthDecode");
         dest_buf = (uint8_t*)last_buf;
         dest_size = last_size;
         pImageParms = pParam;
         return TRUE;
       }
       offset = RunLengthDecode(last_buf, last_size, new_buf, new_size);
+    } else if (decoder == FX_BSTRC("Crypt")) {
+      continue;
     } else {
+      // If we get here, assume it's an image decoder.
       if (decoder == FX_BSTRC("DCT")) {
         decoder = "DCTDecode";
       } else if (decoder == FX_BSTRC("CCF")) {
         decoder = "CCITTFaxDecode";
-      } else if (decoder == FX_BSTRC("Crypt")) {
-        continue;
       }
       ImageEncoding = decoder;
       pImageParms = pParam;
       dest_buf = (uint8_t*)last_buf;
       dest_size = last_size;
+      if (CPDF_Array* pDecoders = pDecoder->AsArray())
+        pDecoders->RemoveAt(i + 1, pDecoders->GetCount() - i - 1);
       return TRUE;
     }
     if (last_buf != src_buf) {
       FX_Free(last_buf);
     }
     if (offset == -1) {
       FX_Free(new_buf);
       return FALSE;
     }
     last_buf = new_buf;
     last_size = new_size;
   }
   ImageEncoding = "";
-  pImageParms = NULL;
+  pImageParms = nullptr;
   dest_buf = last_buf;
   dest_size = last_size;
   return TRUE;
 }
 CFX_WideString PDF_DecodeText(const uint8_t* src_data,
                               FX_DWORD src_len,
                               CFX_CharMap* pCharMap) {
   CFX_WideString result;
   if (src_len >= 2 && ((src_data[0] == 0xfe && src_data[1] == 0xff) ||
                        (src_data[0] == 0xff && src_data[1] == 0xfe))) {
@@ skipping 140 matching lines @@
                      FX_DWORD src_size,
                      uint8_t*& dest_buf,
                      FX_DWORD& dest_size) {
   CCodec_ModuleMgr* pEncoders = CPDF_ModuleMgr::Get()->GetCodecModule();
   if (pEncoders) {
     return pEncoders->GetFlateModule()->FlateOrLZWDecode(
         FALSE, src_buf, src_size, FALSE, 0, 0, 0, 0, 0, dest_buf, dest_size);
   }
   return 0;
 }