Zebediah Figura : msi: Protect communication with the custom action server with a critical section.

[Alexandre Julliard]

Module: wine
Branch: master
Commit: 583edf7f59866cf0a58c978e692f3077e74b4938
URL:    https://source.winehq.org/git/wine.git/?a=commit;h=583edf7f59866cf0a58c978e692f3077e74b4938

Author: Zebediah Figura <z.figura12 at gmail.com>
Date:   Thu Aug 16 10:34:38 2018 -0500

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 at gmail.com>
Signed-off-by: Hans Leidekker <hans at codeweavers.com>
Signed-off-by: Alexandre Julliard <julliard at winehq.org>

---

 dlls/msi/custom.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/dlls/msi/custom.c b/dlls/msi/custom.c
index a9bb81f..9418b42 100644
--- a/dlls/msi/custom.c
+++ b/dlls/msi/custom.c
@@ -683,6 +683,8 @@ 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))
     {
@@ -695,6 +697,8 @@ 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))
     {