[ros-diffs] [reactos] 01/01: [NTUSER] Add locking at IntSendFocusMessage (#4468)

[Katayama Hirofumi MZ]

https://git.reactos.org/?p=reactos.git;a=commitdiff;h=0b0e73d66edc9e6ebff705...

commit 0b0e73d66edc9e6ebff7057d44d1789846016687
Author:     Katayama Hirofumi MZ [e-mail]
AuthorDate: Mon Apr 25 11:36:00 2022 +0900
Commit:     GitHub [e-mail]
CommitDate: Mon Apr 25 11:36:00 2022 +0900

[NTUSER] Add locking at IntSendFocusMessage (#4468)

Fix access violation on IntFocusSetInputContext.
    - Add locking on pWndPrev.
    CORE-18163
---
 win32ss/user/ntuser/focus.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/win32ss/user/ntuser/focus.c b/win32ss/user/ntuser/focus.c
index 7ecb9c88f73..f40a2bf686b 100644
--- a/win32ss/user/ntuser/focus.c
+++ b/win32ss/user/ntuser/focus.c
@@ -617,6 +617,7 @@ IntSendFocusMessages( PTHREADINFO pti, PWND pWnd)
    PWND pWndPrev;
    PUSER_MESSAGE_QUEUE ThreadQueue = pti->MessageQueue; // Queue can change...
    HWND hwndPrev;
+   USER_REFERENCE_ENTRY Ref;

ThreadQueue->QF_flags &= ~QF_FOCUSNULLSINCEACTIVE;
    if (!pWnd && ThreadQueue->spwndActive)
@@ -625,6 +626,8 @@ IntSendFocusMessages( PTHREADINFO pti, PWND pWnd)
    }

pWndPrev = ThreadQueue->spwndFocus;
+   if (pWndPrev)
+      UserRefObjectCo(pWndPrev, &Ref);

/* check if the specified window can be set in the input data of a given queue */
    if (!pWnd || ThreadQueue == pWnd->head.pti->MessageQueue)
@@ -667,6 +670,9 @@ IntSendFocusMessages( PTHREADINFO pti, PWND pWnd)
          }
       }
    }
+
+   if (pWndPrev)
+      UserDerefObjectCo(pWndPrev);
 }

BOOL FASTCALL