Re: [PATCH v2] ole32: Store proxy/stub CLSIDs per process, not per apartment.

[Huw Davies]

On Tue, Aug 01, 2017 at 04:54:45PM -0500, Zebediah Figura wrote:
> v2: use proper synchronization; add an MTA test (thanks Sebastian)
> Signed-off-by: Zebediah Figura
>
> dlls/ole32/compobj.c         | 48 ++++++++++++++++++++++++++++++------------
>  dlls/ole32/compobj_private.h |  1 -
>  dlls/ole32/tests/compobj.c   | 50 ++++++++++++++++++++++++++++++++++++++++++--
>  3 files changed, 83 insertions(+), 16 deletions(-)
>
> diff --git a/dlls/ole32/compobj.c b/dlls/ole32/compobj.c
> index 60244485249..ee904adbc38 100644
> --- a/dlls/ole32/compobj.c
> +++ b/dlls/ole32/compobj.c
> @@ -170,8 +170,20 @@ struct registered_psclsid
>      struct list entry;
>      IID iid;
>      CLSID clsid;
> - OXID apartment_id;
>
> };
>
> +static struct list RegisteredPSCLSIDList = LIST_INIT(RegisteredPSCLSIDList);

Please don't use CamelCase.
> -
>
> +static CRITICAL_SECTION csRegisteredPSCLSIDList;
> +static CRITICAL_SECTION_DEBUG psclsid_cs_debug =
> +{
> - 0, 0, &csRegisteredPSCLSIDList,
> - { &psclsid_cs_debug.ProcessLocksList, &psclsid_cs_debug.ProcessLocksList },
> -
>  0, 0, { (DWORD_PTR)(__FILE__ ": csRegisteredPSCLSIDList") }
>
> +};
> +static CRITICAL_SECTION csRegisteredPSCLSIDList = { &psclsid_cs_debug, -1, 0, 0, 0, 0 };
> -
>
> /*
> - This is a marshallable object exposing registered local servers.
> - IServiceProvider is used only because it happens meet requirements
>
> @@ -622,7 +634,6 @@ static APARTMENT *apartment_construct(DWORD model)
>  list_init(&apt->proxies);
>  list_init(&apt->stubmgrs);
> - list_init(&apt->psclsids);
> list_init(&apt->loaded_dlls);
> apt->ipidc = 0;
> apt->refs = 1;
>
> @@ -1173,15 +1184,22 @@ DWORD apartment_release(struct apartment *apt)
>              stub_manager_int_release(stubmgr);
>          }
> -
>    LIST_FOR_EACH_SAFE(cursor, cursor2, &apt->psclsids)
> -
>    EnterCriticalSection(&csRegisteredPSCLSIDList);
> -
> -
>    LIST_FOR_EACH_SAFE(cursor, cursor2, &RegisteredPSCLSIDList)
>    {
>        struct registered_psclsid *registered_psclsid =
>            LIST_ENTRY(cursor, struct registered_psclsid, entry);
>
> -
>        list_remove(&registered_psclsid->entry);
> -
>        HeapFree(GetProcessHeap(), 0, registered_psclsid);
> -
>        if (registered_psclsid->apartment_id == apt->oxid)
> -
>        {
> -
>            list_remove(&registered_psclsid->entry);
> -
>            HeapFree(GetProcessHeap(), 0, registered_psclsid);
> -
>        }
>    }
>
> -
>    LeaveCriticalSection(&csRegisteredPSCLSIDList);
> -
>    /* if this assert fires, then another thread took a reference to a
>     * stub manager without taking a reference to the containing
>     * apartment, which it must do. */

It seems it's more complicated than this.  Consider two already
existing STAs, if the PSClsid is registered in STA1 which then leaves
the apt, a call in STA2 to CoGetPSCLSID() still succeeds.

You'll want to expand the tests to cover things like this to really figure out
what's going on.

Also note that the MTA -> MTA test isn't very convincing, since there is only
one MTA and hence both threads are in the same apt.

Huw.