Fix UAF after destroying a widget during OnBeforeKeyStroke().chromium/3223

Bug: chromium:766957
Change-Id: I61b282059fb4fc2c8ba6dafc502f030f31dd324d
Reviewed-on: https://pdfium-review.googlesource.com/14710
Commit-Queue: Henrique Nakashima <hnakashima@chromium.org>
Reviewed-by: Tom Sepez <tsepez@chromium.org>

1 files changed, 11 insertions, 0 deletions

diff --git a/fpdfsdk/pwl/cpwl_edit.cpp b/fpdfsdk/pwl/cpwl_edit.cpp
index 0b74a1896e..662c69e369 100644
--- a/fpdfsdk/pwl/cpwl_edit.cpp
+++ b/fpdfsdk/pwl/cpwl_edit.cpp
@@ -481,11 +481,17 @@ bool CPWL_Edit::OnKeyDown(uint16_t nChar, uint32_t nFlag) {
       if (nSelStart == nSelEnd)
         nSelEnd = nSelStart + 1;
 
+      CPWL_Wnd::ObservedPtr thisObserved(this);
+
       bool bRC;
       bool bExit;
       std::tie(bRC, bExit) = m_pFillerNotify->OnBeforeKeyStroke(
           GetAttachedData(), strChange, strChangeEx, nSelStart, nSelEnd, true,
           nFlag);
+
+      if (!thisObserved)
+        return false;
+
       if (!bRC)
         return false;
       if (bExit)
@@ -558,10 +564,15 @@ bool CPWL_Edit::OnChar(uint16_t nChar, uint32_t nFlag) {
           break;
       }
 
+      CPWL_Wnd::ObservedPtr thisObserved(this);
+
       WideString strChangeEx;
       std::tie(bRC, bExit) = m_pFillerNotify->OnBeforeKeyStroke(
           GetAttachedData(), swChange, strChangeEx, nSelStart, nSelEnd, true,
           nFlag);
+
+      if (!thisObserved)
+        return false;
     }
   }