in the attempt to fix 627393, changed IFX_FileRead's readBlock to return the length it reads

core/fpdfapi/parser/cpdf_data_avail.cpp

Index: core/fpdfapi/parser/cpdf_data_avail.cpp
diff --git a/core/fpdfapi/parser/cpdf_data_avail.cpp b/core/fpdfapi/parser/cpdf_data_avail.cpp
index 3fe4b03da62012ae33d8cbf50944708e5572224f..4df1a140e7a683254b9b93af8dc1eafedbe3796e 100644
--- a/core/fpdfapi/parser/cpdf_data_avail.cpp
+++ b/core/fpdfapi/parser/cpdf_data_avail.cpp
@@ -957,7 +957,9 @@ bool CPDF_DataAvail::GetNextChar(uint8_t& ch) {
     if ((FX_FILESIZE)(read_pos + read_size) > m_dwFileLen)
       read_pos = m_dwFileLen - read_size;
 
-    if (!m_pFileRead->ReadBlock(m_bufferData, read_pos, read_size))
+    if (m_pFileRead->ReadBlock(m_bufferData, read_pos, read_size) !=
+            read_size &&
+        !m_pFileRead->IsEOF())
       return false;
 
     m_bufferOffset = read_pos;
@@ -1062,7 +1064,8 @@ bool CPDF_DataAvail::CheckTrailer(DownloadHints* pHints) {
   int32_t iTrailerSize =
       (int32_t)(m_Pos + 512 > m_dwFileLen ? m_dwFileLen - m_Pos : 512);
   if (m_pFileAvail->IsDataAvail(m_Pos, iTrailerSize)) {
-    int32_t iSize = (int32_t)(m_Pos + iTrailerSize - m_dwTrailerOffset);
+    uint32_t iSize = pdfium::base::checked_cast<uint32_t>(m_Pos + iTrailerSize -
+                                                          m_dwTrailerOffset);
     CFX_BinaryBuf buf(iSize);
     uint8_t* pBuf = buf.GetBuffer();
     if (!pBuf) {
@@ -1070,7 +1073,8 @@ bool CPDF_DataAvail::CheckTrailer(DownloadHints* pHints) {
       return false;
     }
 
-    if (!m_pFileRead->ReadBlock(pBuf, m_dwTrailerOffset, iSize))
+    if (m_pFileRead->ReadBlock(pBuf, m_dwTrailerOffset, iSize) != iSize &&
+        !m_pFileRead->IsEOF())
       return false;
 
     ScopedFileStream file(FX_CreateMemoryStream(pBuf, (size_t)iSize, false));

[Tom Sepez, 2016/11/14 20:27:40]

same issue here with reads < isize.