2 files changed, 3 insertions, 3 deletions
diff --git a/core/fpdfapi/fpdf_parser/cpdf_data_avail.cpp b/core/fpdfapi/fpdf_parser/cpdf_data_avail.cpp
index a4b85a34fa..15f98b26b9 100644
--- a/core/fpdfapi/fpdf_parser/cpdf_data_avail.cpp
+++ b/core/fpdfapi/fpdf_parser/cpdf_data_avail.cpp
@@ -716,10 +716,10 @@ FX_BOOL CPDF_DataAvail::CheckFirstPage(IPDF_DataAvail::DownloadHints* pHints) {
 FX_BOOL CPDF_DataAvail::IsDataAvail(FX_FILESIZE offset,
                                     uint32_t size,
                                     IPDF_DataAvail::DownloadHints* pHints) {
-  if (offset > m_dwFileLen)
+  if (offset < 0 || offset > m_dwFileLen)
     return TRUE;
 
-  FX_SAFE_DWORD safeSize = pdfium::base::checked_cast<uint32_t>(offset);
+  FX_SAFE_FILESIZE safeSize = offset;
   safeSize += size;
   safeSize += 512;
   if (!safeSize.IsValid() || safeSize.ValueOrDie() > m_dwFileLen)
diff --git a/core/fpdfapi/fpdf_parser/cpdf_syntax_parser.h b/core/fpdfapi/fpdf_parser/cpdf_syntax_parser.h
index 26b6a8d3df..04fe6f4fec 100644
--- a/core/fpdfapi/fpdf_parser/cpdf_syntax_parser.h
+++ b/core/fpdfapi/fpdf_parser/cpdf_syntax_parser.h
@@ -83,7 +83,7 @@ class CPDF_SyntaxParser {
   FX_FILESIZE m_Pos;
   int m_MetadataObjnum;
   IFX_FileRead* m_pFileAccess;
-  uint32_t m_HeaderOffset;
+  FX_FILESIZE m_HeaderOffset;
   FX_FILESIZE m_FileLen;
   uint8_t* m_pFileBuf;
   uint32_t m_BufSize;