Prevent an OOB access in CPDF_DIBSource::TranslateScanline24bpp

core/fpdfapi/fpdf_render/fpdf_render_loadimage.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/fpdfapi/fpdf_render/render_int.h"
 
 #include <algorithm>
 #include <memory>
@@ skipping 900 matching lines @@
 }
 
 void CPDF_DIBSource::TranslateScanline24bpp(uint8_t* dest_scan,
                                             const uint8_t* src_scan) const {
   if (m_bpc == 0) {
     return;
   }
   unsigned int max_data = (1 << m_bpc) - 1;
   if (m_bDefaultDecode) {
     if (m_Family == PDFCS_DEVICERGB || m_Family == PDFCS_CALRGB) {
+      if (m_nComponents != 3)
+        return;
+
       const uint8_t* src_pos = src_scan;
       switch (m_bpc) {
         case 16:
           for (int col = 0; col < m_Width; col++) {
             *dest_scan++ = src_pos[4];
             *dest_scan++ = src_pos[2];
             *dest_scan++ = *src_pos;
             src_pos += 6;
           }
           break;
@@ skipping 637 matching lines @@
                                    IFX_Pause* pPause) {
   return LoadHandle->Continue(pPause);
 }
 
 CPDF_ImageLoader::~CPDF_ImageLoader() {
   if (!m_bCached) {
     delete m_pBitmap;
     delete m_pMask;
   }
 }