[PATCH 0/1] MR7868: combase: Find correct apartment in ClientRpcChannelBuffer_SendReceive().

[PATCH 1/1] combase: Find correct apartment in ClientRpcChannelBuffer_SendReceive().

[Dmitry Timoshkov]

From: Dmitry Timoshkov

When an application has both apartment-threaded and multi-threaded apartments
then apartment_get_current_or_mta() may return wrong one, and later the oxid
check will fail. Probably it's better try to find correct apartment from the start.

Signed-off-by: Dmitry Timoshkov 
---
 dlls/combase/rpc.c | 15 ++-------------
 1 file changed, 2 insertions(+), 13 deletions(-)

diff --git a/dlls/combase/rpc.c b/dlls/combase/rpc.c
index c51b59de4bf..160c5c579b2 100644
--- a/dlls/combase/rpc.c
+++ b/dlls/combase/rpc.c
@@ -1344,15 +1344,6 @@ static DWORD WINAPI rpc_sendreceive_thread(LPVOID param)
     return 0;
 }

-static inline HRESULT ClientRpcChannelBuffer_IsCorrectApartment(ClientRpcChannelBuffer *This, const struct apartment *apt)
-{
-    if (!apt)
-        return S_FALSE;
-    if (This->oxid != apartment_getoxid(apt))
-        return S_FALSE;
-    return S_OK;
-}
-
 static HRESULT WINAPI ClientRpcChannelBuffer_SendReceive(LPRPCCHANNELBUFFER iface, RPCOLEMESSAGE *olemsg, ULONG *pstatus)
 {
     ClientRpcChannelBuffer *This = (ClientRpcChannelBuffer *)iface;
@@ -1365,17 +1356,15 @@ static HRESULT WINAPI ClientRpcChannelBuffer_SendReceive(LPRPCCHANNELBUFFER ifac
     ORPC_EXTENT_ARRAY orpc_ext_array;
     WIRE_ORPC_EXTENT *first_wire_orpc_extent = NULL;
     HRESULT hrFault = S_OK;
-    struct apartment *apt = apartment_get_current_or_mta();
+    struct apartment *apt = apartment_findfromoxid(This->oxid);
     struct tlsdata *tlsdata;

TRACE("%p, iMethod %ld\n", olemsg, olemsg->iMethod);

-    hr = ClientRpcChannelBuffer_IsCorrectApartment(This, apt);
-    if (hr != S_OK)
+    if (!apt)
     {
         ERR("called from wrong apartment, should have been 0x%s\n",
             wine_dbgstr_longlong(This->oxid));
-        if (apt) apartment_release(apt);
         return RPC_E_WRONG_THREAD;
     }

[Huw Davies (＠huw)]

Could we come up with a test for this?

[Dmitry Timoshkov (＠dmitry)]

On Mon Apr 28 17:42:29 2025 +0000, Huw Davies wrote:
> Could we come up with a test for this?

I tried, however I couldn't reproduce this in a test.

Observed behaviour is similar to what b4da14035741f287130002b512c7d0e9117da80a has fixed, and in that case creating a test also proved to be problematic.

[PATCH 0/1] MR7868: combase: Find correct apartment in ClientRpcChannelBuffer_SendReceive(). - approved

[Huw Davies (＠huw)]

This merge request was approved by Huw Davies.

[Huw Davies (＠huw)]

On Mon Apr 28 17:42:29 2025 +0000, Dmitry Timoshkov wrote:
> I tried, however I couldn't reproduce this in a test.
> Observed behaviour is similar to what
> b4da14035741f287130002b512c7d0e9117da80a has fixed, and in that case
> creating a test also proved to be problematic.

Right, ok. Makes sense.