From 4df46054105e71ecc6a80d29c8d56ef0778b5aa8 Mon Sep 17 00:00:00 2001
From: Lei Zhang <thestig@chromium.org>
Date: Thu, 18 Oct 2018 16:58:07 +0000
Subject: Cache CFGAS_FontMgr::GetFontByUnicode() failures on Windows.

Non-Windows does this already, which is why it can handle fuzzers that
throws the same invalid unicode character at it efficiently. Whereas
Windows tries to do the same failing font load repeatedly.

BUG=chromium:895469

Change-Id: I6780d1ec0881222348e05a5a63e7b2238f39a3a6
Reviewed-on: https://pdfium-review.googlesource.com/c/44251
Commit-Queue: Lei Zhang <thestig@chromium.org>
Reviewed-by: Tom Sepez <tsepez@chromium.org>
---
 xfa/fgas/font/cfgas_fontmgr.cpp | 44 ++++++++++++++++++++---------------------
 xfa/fgas/font/cfgas_fontmgr.h   |  2 +-
 2 files changed, 23 insertions(+), 23 deletions(-)

diff --git a/xfa/fgas/font/cfgas_fontmgr.cpp b/xfa/fgas/font/cfgas_fontmgr.cpp
index 8881be74f6..22e97f076c 100644
--- a/xfa/fgas/font/cfgas_fontmgr.cpp
+++ b/xfa/fgas/font/cfgas_fontmgr.cpp
@@ -27,6 +27,23 @@
 #include "xfa/fgas/font/cfx_fontsourceenum_file.h"
 #endif
 
+namespace {
+
+bool VerifyUnicode(const RetainPtr<CFGAS_GEFont>& pFont, wchar_t wcUnicode) {
+  FXFT_Face pFace = pFont->GetDevFont()->GetFace();
+  FXFT_CharMap charmap = FXFT_Get_Face_Charmap(pFace);
+  if (FXFT_Select_Charmap(pFace, FXFT_ENCODING_UNICODE) != 0)
+    return false;
+
+  if (FXFT_Get_Char_Index(pFace, wcUnicode) == 0) {
+    FXFT_Set_Charmap(pFace, charmap);
+    return false;
+  }
+  return true;
+}
+
+}  // namespace
+
 #if _FX_PLATFORM_ == _FX_PLATFORM_WINDOWS_
 
 namespace {
@@ -182,6 +199,11 @@ RetainPtr<CFGAS_GEFont> CFGAS_FontMgr::GetFontByUnicodeImpl(
     return nullptr;
 
   pFont->SetLogicalFontStyle(dwFontStyles);
+  if (!VerifyUnicode(pFont, wUnicode)) {
+    m_FailedUnicodesSet.insert(wUnicode);
+    return nullptr;
+  }
+
   m_Hash2Fonts[dwHash].push_back(pFont);
   return pFont;
 }
@@ -779,26 +801,6 @@ void CFGAS_FontMgr::RegisterFaces(
 
 #endif  // _FX_PLATFORM_ == _FX_PLATFORM_WINDOWS_
 
-namespace {
-
-bool VerifyUnicode(const RetainPtr<CFGAS_GEFont>& pFont, wchar_t wcUnicode) {
-  if (!pFont)
-    return false;
-
-  FXFT_Face pFace = pFont->GetDevFont()->GetFace();
-  FXFT_CharMap charmap = FXFT_Get_Face_Charmap(pFace);
-  if (FXFT_Select_Charmap(pFace, FXFT_ENCODING_UNICODE) != 0)
-    return false;
-
-  if (FXFT_Get_Char_Index(pFace, wcUnicode) == 0) {
-    FXFT_Set_Charmap(pFace, charmap);
-    return false;
-  }
-  return true;
-}
-
-}  // namespace
-
 RetainPtr<CFGAS_GEFont> CFGAS_FontMgr::GetFontByCodePage(
     uint16_t wCodePage,
     uint32_t dwFontStyles,
@@ -857,10 +859,8 @@ RetainPtr<CFGAS_GEFont> CFGAS_FontMgr::GetFontByUnicode(
     wchar_t wUnicode,
     uint32_t dwFontStyles,
     const wchar_t* pszFontFamily) {
-#if _FX_PLATFORM_ != _FX_PLATFORM_WINDOWS_
   if (pdfium::ContainsKey(m_FailedUnicodesSet, wUnicode))
     return nullptr;
-#endif  // _FX_PLATFORM_ != _FX_PLATFORM_WINDOWS_
 
   const FGAS_FONTUSB* x = FGAS_GetUnicodeBitField(wUnicode);
   uint16_t wCodePage = x ? x->wCodePage : 0xFFFF;
diff --git a/xfa/fgas/font/cfgas_fontmgr.h b/xfa/fgas/font/cfgas_fontmgr.h
index b784bedfe8..389f96ab1d 100644
--- a/xfa/fgas/font/cfgas_fontmgr.h
+++ b/xfa/fgas/font/cfgas_fontmgr.h
@@ -145,6 +145,7 @@ class CFGAS_FontMgr final : public Observable<CFGAS_FontMgr> {
 #endif  // _FX_PLATFORM_ == _FX_PLATFORM_WINDOWS_
 
   std::map<uint32_t, std::vector<RetainPtr<CFGAS_GEFont>>> m_Hash2Fonts;
+  std::set<wchar_t> m_FailedUnicodesSet;
 
 #if _FX_PLATFORM_ == _FX_PLATFORM_WINDOWS_
   std::deque<FX_FONTDESCRIPTOR> m_FontFaces;
@@ -155,7 +156,6 @@ class CFGAS_FontMgr final : public Observable<CFGAS_FontMgr> {
       m_Hash2CandidateList;
   std::map<RetainPtr<CFGAS_GEFont>, RetainPtr<IFX_SeekableReadStream>>
       m_IFXFont2FileRead;
-  std::set<wchar_t> m_FailedUnicodesSet;
 #endif  // _FX_PLATFORM_ == _FX_PLATFORM_WINDOWS_
 };
 
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