From b1b2cc1e8d83431bb5acce3f341b6748acb1da34 Mon Sep 17 00:00:00 2001
From: winesync <ros-dev@reactos.org>
Date: Sat, 12 Mar 2022 23:54:31 +0100
Subject: [PATCH] [WINESYNC] msi: Protect communication with the custom action
 server with a critical section.

Avoids a potential race whereby an asynchronous custom action receives the
wrong thread handle.

Signed-off-by: Zebediah Figura <z.figura12@gmail.com>
Signed-off-by: Hans Leidekker <hans@codeweavers.com>
Signed-off-by: Alexandre Julliard <julliard@winehq.org>

wine commit id 583edf7f59866cf0a58c978e692f3077e74b4938 by Zebediah Figura <z.figura12@gmail.com>
---
 dll/win32/msi/custom.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/dll/win32/msi/custom.c b/dll/win32/msi/custom.c
index 3d426190f00..9cf3ba1081c 100644
--- a/dll/win32/msi/custom.c
+++ b/dll/win32/msi/custom.c
@@ -698,6 +698,8 @@ static DWORD WINAPI custom_client_thread(void *arg)
         pipe = info->package->custom_server_64_pipe;
     }
 
+    EnterCriticalSection(&msi_custom_action_cs);
+
     if (!WriteFile(pipe, &info->guid, sizeof(info->guid), &size, NULL) ||
         size != sizeof(info->guid))
     {
@@ -710,6 +712,8 @@ static DWORD WINAPI custom_client_thread(void *arg)
         return GetLastError();
     }
 
+    LeaveCriticalSection(&msi_custom_action_cs);
+
     if (DuplicateHandle(process, (HANDLE)(DWORD_PTR)thread64, GetCurrentProcess(),
         &thread, 0, FALSE, DUPLICATE_SAME_ACCESS | DUPLICATE_CLOSE_SOURCE))
     {