Fix UAF in CFGAS_FontMgr::FindFontchromium/3398

Fix an use-after-free issue which was introduced by
commit 53279b1dcabae4913f7f0a58e741942e82ab7d59.

Bug: chromium:832589
Change-Id: Id7da791c3aa2d71d0a9e56d062069f41b7eb48d1
Reviewed-on: https://pdfium-review.googlesource.com/30570
Commit-Queue: Lei Zhang <thestig@chromium.org>
Reviewed-by: Lei Zhang <thestig@chromium.org>

1 files changed, 5 insertions, 1 deletions

diff --git a/xfa/fgas/font/cfgas_fontmgr.cpp b/xfa/fgas/font/cfgas_fontmgr.cpp
index b4e6bdc912..d7acc62eef 100644
--- a/xfa/fgas/font/cfgas_fontmgr.cpp
+++ b/xfa/fgas/font/cfgas_fontmgr.cpp
@@ -229,8 +229,12 @@ const FX_FONTDESCRIPTOR* CFGAS_FontMgr::FindFont(const wchar_t* pszFontFamily,
   if (!pszFontFamily)
     return nullptr;
 
+  // Use a named object to store the returned value of EnumGdiFonts() instead
+  // of using a temporary object. This can prevent use-after-free issues since
+  // pDesc may point to one of std::deque object's elements.
+  std::deque<FX_FONTDESCRIPTOR> namedFonts = EnumGdiFonts(pszFontFamily, wUnicode);
   params.pwsFamily = nullptr;
-  pDesc = MatchDefaultFont(&params, EnumGdiFonts(pszFontFamily, wUnicode));
+  pDesc = MatchDefaultFont(&params, namedFonts);
   if (!pDesc)
     return nullptr;