Fix the potential integer overflow from "offset + size".
BUG=382667
R=jschuh@chromium.org, jun_fang@foxitsoftware.com
Review URL: https://codereview.chromium.org/390983007
diff --git a/core/src/fpdfapi/fpdf_parser/fpdf_parser_parser.cpp b/core/src/fpdfapi/fpdf_parser/fpdf_parser_parser.cpp
index f82bf3a..14597d9 100644
--- a/core/src/fpdfapi/fpdf_parser/fpdf_parser_parser.cpp
+++ b/core/src/fpdfapi/fpdf_parser/fpdf_parser_parser.cpp
@@ -2864,13 +2864,27 @@
CPDF_Reference *pRef = (CPDF_Reference*)pObj;
FX_DWORD dwNum = pRef->GetRefObjNum();
FX_FILESIZE offset;
- FX_DWORD size = GetObjectSize(pRef->GetRefObjNum(), offset);
- if (!size) {
+ FX_DWORD original_size = GetObjectSize(dwNum, offset);
+ base::CheckedNumeric<FX_DWORD> size = original_size;
+ if (size.ValueOrDefault(0) == 0 || offset < 0 || offset >= m_dwFileLen) {
break;
}
- size = (FX_DWORD)((FX_FILESIZE)(offset + size + 512) > m_dwFileLen ? m_dwFileLen - offset : size + 512);
- if (!m_pFileAvail->IsDataAvail(offset, size)) {
- pHints->AddSegment(offset, size);
+
+ size += offset;
+ size += 512;
+ if (!size.IsValid()) {
+ break;
+ }
+ if (size.ValueOrDie() > m_dwFileLen) {
+ size = m_dwFileLen - offset;
+ } else {
+ size = original_size + 512;
+ }
+ if (!size.IsValid()) {
+ break;
+ }
+ if (!m_pFileAvail->IsDataAvail(offset, size.ValueOrDie())) {
+ pHints->AddSegment(offset, size.ValueOrDie());
ret_array.Add(pObj);
count++;
} else if (!m_objnum_array.Find(dwNum)) {
