[PATCH v2 1/1] mf: Avoid a double free of presentation clock timers.

[Zhiyi Zhang]

From: Zhiyi Zhang

In clock_change_state() when a clock is running, a timer is removed from clock->timers. The same
timer is then used to create an async result, which will eventually calls present_clock_timer_callback_Invoke()
and release the same timer. This patch checks if the timer is still in clock->timers before releasing it.
---
 dlls/mf/clock.c | 14 ++++++++++----
 1 file changed, 10 insertions(+), 4 deletions(-)

diff --git a/dlls/mf/clock.c b/dlls/mf/clock.c
index aef4366c6d9..e6be05d2794 100644
--- a/dlls/mf/clock.c
+++ b/dlls/mf/clock.c
@@ -1108,13 +1108,19 @@ static HRESULT WINAPI present_clock_timer_callback_Invoke(IMFAsyncCallback *ifac
     if (FAILED(hr = IMFAsyncResult_GetObject(result, &object)))
         return hr;

-    timer = impl_clock_timer_from_IUnknown(object);
-
     EnterCriticalSection(&clock->cs);
-    list_remove(&timer->entry);
-    IUnknown_Release(&timer->IUnknown_iface);
+    LIST_FOR_EACH_ENTRY(timer, &clock->timers, struct clock_timer, entry)
+    {
+        if (&timer->IUnknown_iface == object)
+        {
+            list_remove(&timer->entry);
+            IUnknown_Release(&timer->IUnknown_iface);
+            break;
+        }
+    }
     LeaveCriticalSection(&clock->cs);

+    timer = impl_clock_timer_from_IUnknown(object);
     IMFAsyncCallback_Invoke(timer->callback, timer->result);

IUnknown_Release(object);