Use UnownedPtr instead of T* in MaybeOwned.

Always check the liftime in the unowned case. Doing so unearthed
the following issues:

Transient lifetime issue in jbig2_image when doing realloc().
Stale (but unused) dictionary pointer in CPDF_Image.
Destruction order in error branch in cpdf_dibsource.cpp

Change-Id: I12b758aafeefedc7abe1e8b21a18db959929e95f
Reviewed-on: https://pdfium-review.googlesource.com/24552
Commit-Queue: Tom Sepez <tsepez@chromium.org>
Reviewed-by: dsinclair <dsinclair@chromium.org>

2 files changed, 11 insertions, 19 deletions

diff --git a/core/fpdfapi/page/cpdf_image.cpp b/core/fpdfapi/page/cpdf_image.cpp
index 65ca78e08e..5f82886a9b 100644
--- a/core/fpdfapi/page/cpdf_image.cpp
+++ b/core/fpdfapi/page/cpdf_image.cpp
@@ -35,33 +35,27 @@ CPDF_Image::CPDF_Image(CPDF_Document* pDoc) : m_pDocument(pDoc) {}
 
 CPDF_Image::CPDF_Image(CPDF_Document* pDoc,
                        std::unique_ptr<CPDF_Stream> pStream)
-    : m_bIsInline(true),
-      m_pDocument(pDoc),
-      m_pStream(std::move(pStream)),
-      m_pDict(ToDictionary(m_pStream->GetDict()->Clone())) {
+    : m_bIsInline(true), m_pDocument(pDoc), m_pStream(std::move(pStream)) {
   ASSERT(m_pStream.IsOwned());
-  ASSERT(m_pDict.IsOwned());
-  FinishInitialization();
+  FinishInitialization(m_pStream->GetDict());
 }
 
 CPDF_Image::CPDF_Image(CPDF_Document* pDoc, uint32_t dwStreamObjNum)
     : m_pDocument(pDoc),
-      m_pStream(ToStream(pDoc->GetIndirectObject(dwStreamObjNum))),
-      m_pDict(m_pStream->GetDict()) {
+      m_pStream(ToStream(pDoc->GetIndirectObject(dwStreamObjNum))) {
   ASSERT(!m_pStream.IsOwned());
-  ASSERT(!m_pDict.IsOwned());
-  FinishInitialization();
+  FinishInitialization(m_pStream->GetDict());
 }
 
 CPDF_Image::~CPDF_Image() {}
 
-void CPDF_Image::FinishInitialization() {
-  m_pOC = m_pDict->GetDictFor("OC");
+void CPDF_Image::FinishInitialization(CPDF_Dictionary* pDict) {
+  m_pOC = pDict->GetDictFor("OC");
   m_bIsMask =
-      !m_pDict->KeyExist("ColorSpace") || m_pDict->GetIntegerFor("ImageMask");
-  m_bInterpolate = !!m_pDict->GetIntegerFor("Interpolate");
-  m_Height = m_pDict->GetIntegerFor("Height");
-  m_Width = m_pDict->GetIntegerFor("Width");
+      !pDict->KeyExist("ColorSpace") || pDict->GetIntegerFor("ImageMask");
+  m_bInterpolate = !!pDict->GetIntegerFor("Interpolate");
+  m_Height = pDict->GetIntegerFor("Height");
+  m_Width = pDict->GetIntegerFor("Width");
 }
 
 void CPDF_Image::ConvertStreamToIndirectObject() {
diff --git a/core/fpdfapi/page/cpdf_image.h b/core/fpdfapi/page/cpdf_image.h
index 23864bbf6c..57cbe94ca2 100644
--- a/core/fpdfapi/page/cpdf_image.h
+++ b/core/fpdfapi/page/cpdf_image.h
@@ -29,7 +29,6 @@ class CPDF_Image : public Retainable {
 
   void ConvertStreamToIndirectObject();
 
-  CPDF_Dictionary* GetInlineDict() const { return m_pDict.Get(); }
   CPDF_Stream* GetStream() const { return m_pStream.Get(); }
   CPDF_Dictionary* GetDict() const;
   CPDF_Dictionary* GetOC() const { return m_pOC.Get(); }
@@ -68,7 +67,7 @@ class CPDF_Image : public Retainable {
   CPDF_Image(CPDF_Document* pDoc, uint32_t dwStreamObjNum);
   ~CPDF_Image() override;
 
-  void FinishInitialization();
+  void FinishInitialization(CPDF_Dictionary* pStreamDict);
   std::unique_ptr<CPDF_Dictionary> InitJPEG(uint8_t* pData, uint32_t size);
 
   int32_t m_Height = 0;
@@ -78,7 +77,6 @@ class CPDF_Image : public Retainable {
   bool m_bInterpolate = false;
   UnownedPtr<CPDF_Document> const m_pDocument;
   MaybeOwned<CPDF_Stream> m_pStream;
-  MaybeOwned<CPDF_Dictionary> m_pDict;
   UnownedPtr<CPDF_Dictionary> m_pOC;
 };