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- Document how thread-safety is ensured for each member of the

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stub_manager and ifstub structs.
- Make stub_manager ref counted to ensure it doesn't get freed whilst
  it is still being used.
- ifstubs are now freed only when the controlling stub_manager is freed.
- Rename stub_manager_ref/unref to stub_manager_ext_addref/release
  respectively and make then take an unsigned long to prevent
  malicious callers from passing in a negative value and corrupting
  the ref count.
This commit is contained in:
Robert Shearman 2005-01-11 10:45:34 +00:00 committed by Alexandre Julliard
parent 6f20133705
commit c353f85082
4 changed files with 155 additions and 106 deletions
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47
dlls/ole32/compobj_private.h
View File

@ -139,41 +139,52 @@ MARSHAL_Compare_Mids(wine_marshal_id *mid1,wine_marshal_id *mid2) {
HRESULT MARSHAL_Disconnect_Proxies(APARTMENT *apt);
HRESULT MARSHAL_GetStandardMarshalCF(LPVOID *ppv);
/* Thread-safety Annotation Legend:
*
* RO - The value is read only. It never changes after creation, so no
* locking is required.
* LOCK - The value is written to only using Interlocked* functions.
* CS - The value is read or written to with a critical section held.
* The identifier following "CS" is the specific critical section that
* must be used.
*/
/* an interface stub */
struct ifstub
{
struct list entry;
IRpcStubBuffer *stubbuffer;
IID iid;
IPID ipid;
IUnknown *iface;
BOOL table;
struct list entry; /* entry in stub_manager->ifstubs list (CS stub_manager->lock) */
IRpcStubBuffer *stubbuffer; /* RO */
IID iid; /* RO */
IPID ipid; /* RO */
IUnknown *iface; /* RO */
BOOL table; /* CS stub_manager->lock */
};
/* stub managers hold refs on the object and each interface stub */
struct stub_manager
{
struct list entry;
struct list ifstubs;
struct list entry; /* entry in apartment stubmgr list (CS apt->cs) */
struct list ifstubs; /* list of active ifstubs for the object (CS lock) */
CRITICAL_SECTION lock;
APARTMENT *apt; /* owning apt */
APARTMENT *apt; /* owning apt (RO) */
DWORD refcount; /* count of 'external' references */
OID oid; /* apartment-scoped unique identifier */
IUnknown *object; /* the object we are managing the stub for */
DWORD next_ipid; /* currently unused */
ULONG extrefs; /* number of 'external' references (LOCK) */
ULONG refs; /* internal reference count (CS apt->cs) */
OID oid; /* apartment-scoped unique identifier (RO) */
IUnknown *object; /* the object we are managing the stub for (RO) */
ULONG next_ipid; /* currently unused (LOCK) */
};
ULONG stub_manager_int_addref(struct stub_manager *This);
ULONG stub_manager_int_release(struct stub_manager *This);
struct stub_manager *new_stub_manager(APARTMENT *apt, IUnknown *object);
int stub_manager_ref(struct stub_manager *m, int refs);
int stub_manager_unref(struct stub_manager *m, int refs);
IRpcStubBuffer *stub_manager_ipid_to_stubbuffer(struct stub_manager *m, IPID *iid);
ULONG stub_manager_ext_addref(struct stub_manager *m, ULONG refs);
ULONG stub_manager_ext_release(struct stub_manager *m, ULONG refs);
IRpcStubBuffer *stub_manager_ipid_to_stubbuffer(struct stub_manager *m, const IPID *iid);
struct ifstub *stub_manager_new_ifstub(struct stub_manager *m, IRpcStubBuffer *sb, IUnknown *iptr, REFIID iid, BOOL tablemarshal);
struct stub_manager *get_stub_manager(OXID oxid, OID oid);
struct stub_manager *get_stub_manager_from_object(OXID oxid, void *object);
void stub_manager_delete_ifstub(struct stub_manager *m, IPID *ipid);
IRpcStubBuffer *mid_to_stubbuffer(wine_marshal_id *mid);

37
dlls/ole32/marshal.c
View File

@ -83,6 +83,7 @@ typedef struct _wine_marshal_data {
IRpcStubBuffer *mid_to_stubbuffer(wine_marshal_id *mid)
{
IRpcStubBuffer *ret;
struct stub_manager *m;
if (!(m = get_stub_manager(mid->oxid, mid->oid)))
@ -91,7 +92,10 @@ IRpcStubBuffer *mid_to_stubbuffer(wine_marshal_id *mid)
return NULL;
}
return stub_manager_ipid_to_stubbuffer(m, &mid->ipid);
ret = stub_manager_ipid_to_stubbuffer(m, &mid->ipid);
stub_manager_int_release(m);
return ret;
}
/* creates a new stub manager and sets mid->oid when mid->oid == 0 */
@ -117,16 +121,23 @@ static HRESULT register_ifstub(wine_marshal_id *mid, REFIID riid, IUnknown *obj,
COM_ApartmentRelease(apt);
if (!manager) return E_OUTOFMEMORY;
if (!tablemarshal) stub_manager_ref(manager, 1);
mid->oid = manager->oid;
}
ifstub = stub_manager_new_ifstub(manager, stub, obj, riid, tablemarshal);
if (!ifstub)
{
stub_manager_int_release(manager);
/* FIXME: should we do another release to completely destroy the
* stub manager? */
return E_OUTOFMEMORY;
}
if (!tablemarshal) stub_manager_ext_addref(manager, 1);
mid->ipid = ifstub->ipid;
stub_manager_int_release(manager);
return S_OK;
}
@ -510,6 +521,7 @@ StdMarshalImpl_MarshalInterface(
if ((manager = get_stub_manager_from_object(mid.oxid, pUnk)))
{
mid.oid = manager->oid;
stub_manager_int_release(manager);
}
else
{
@ -560,7 +572,8 @@ StdMarshalImpl_UnmarshalInterface(LPMARSHAL iface, IStream *pStm, REFIID riid, v
if (hres) return hres;
/* check if we're marshalling back to ourselves */
if ((stubmgr = get_stub_manager(mid.oxid, mid.oid)))
/* FIXME: commented out until we can get the tests passing with it uncommented. */
if (/*(apt->oxid == mid.oxid) &&*/ (stubmgr = get_stub_manager(mid.oxid, mid.oid)))
{
TRACE("Unmarshalling object marshalled in same apartment for iid %s, returning original object %p\n", debugstr_guid(riid), stubmgr->object);
@ -568,9 +581,10 @@ StdMarshalImpl_UnmarshalInterface(LPMARSHAL iface, IStream *pStm, REFIID riid, v
if ((md.mshlflags & MSHLFLAGS_TABLESTRONG) || (md.mshlflags & MSHLFLAGS_TABLEWEAK))
FIXME("table marshalling unimplemented\n");
/* clean up the stubs */
stub_manager_delete_ifstub(stubmgr, &mid.ipid);
stub_manager_unref(stubmgr, 1);
/* unref the ifstub. FIXME: only do this on success? */
stub_manager_ext_release(stubmgr, 1);
stub_manager_int_release(stubmgr);
return hres;
}
@ -616,12 +630,9 @@ StdMarshalImpl_ReleaseMarshalData(LPMARSHAL iface, IStream *pStm) {
return RPC_E_INVALID_OBJREF;
}
/* currently, each marshal has its own interface stub. this might
* not be correct. but, it means we don't need to refcount anything
* here. */
stub_manager_delete_ifstub(stubmgr, &mid.ipid);
stub_manager_unref(stubmgr, 1);
stub_manager_ext_release(stubmgr, 1);
stub_manager_int_release(stubmgr);
return S_OK;
}

7
dlls/ole32/rpc.c
View File

@ -791,9 +791,10 @@ COM_RpcReceive(wine_pipe *xpipe) {
goto end;
}
/* this should destroy the stub manager in the case of only one connection to it */
stub_manager_unref(stubmgr, 1);
stub_manager_ext_release(stubmgr, 1);
stub_manager_int_release(stubmgr);
goto end;
} else if (reqtype == REQTYPE_REQUEST) {
wine_rpc_request *xreq;

170
dlls/ole32/stubmanager.c
View File

@ -6,6 +6,7 @@
*
* Copyright 2002 Marcus Meissner
* Copyright 2004 Mike Hearn for CodeWeavers
* Copyright 2004 Robert Shearman (for CodeWeavers)
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
@ -41,6 +42,12 @@
WINE_DEFAULT_DEBUG_CHANNEL(ole);
static void stub_manager_delete_ifstub(struct stub_manager *m, struct ifstub *ifstub);
static struct ifstub *stub_manager_ipid_to_ifstub(struct stub_manager *m, const IPID *ipid);
/* creates a new stub manager and adds it into the apartment. caller must
* release stub manager when it is no longer required. the apartment and
* external refs together take one implicit ref */
struct stub_manager *new_stub_manager(APARTMENT *apt, IUnknown *object)
{
struct stub_manager *sm;
@ -55,19 +62,21 @@ struct stub_manager *new_stub_manager(APARTMENT *apt, IUnknown *object)
IUnknown_AddRef(object);
sm->object = object;
sm->apt = apt;
EnterCriticalSection(&apt->cs);
sm->oid = apt->oidc++;
LeaveCriticalSection(&apt->cs);
/* start off with 2 references because the stub is in the apartment
* and the caller will also hold a reference */
sm->refs = 2;
/* yes, that's right, this starts at zero. that's zero EXTERNAL
* refs, ie nobody has unmarshalled anything yet. we can't have
* negative refs because the stub manager cannot be explicitly
* killed, it has to die by somebody unmarshalling then releasing
* the marshalled ifptr.
*/
sm->refcount = 0;
sm->extrefs = 0;
EnterCriticalSection(&apt->cs);
sm->oid = apt->oidc++;
list_add_head(&apt->stubmgrs, &sm->entry);
LeaveCriticalSection(&apt->cs);
@ -76,6 +85,30 @@ struct stub_manager *new_stub_manager(APARTMENT *apt, IUnknown *object)
return sm;
}
/* m->apt->cs must be held on entry to this function */
static void stub_manager_delete(struct stub_manager *m)
{
struct list *cursor;
TRACE("destroying %p (oid=%s)\n", m, wine_dbgstr_longlong(m->oid));
list_remove(&m->entry);
while ((cursor = list_head(&m->ifstubs)))
{
struct ifstub *ifstub = LIST_ENTRY(cursor, struct ifstub, entry);
stub_manager_delete_ifstub(m, ifstub);
}
IUnknown_Release(m->object);
DeleteCriticalSection(&m->lock);
HeapFree(GetProcessHeap(), 0, m);
}
/* gets the stub manager associated with an object - caller must call
* release on the stub manager when it is no longer needed */
struct stub_manager *get_stub_manager_from_object(OXID oxid, void *object)
{
struct stub_manager *result = NULL;
@ -96,6 +129,7 @@ struct stub_manager *get_stub_manager_from_object(OXID oxid, void *object)
if (m->object == object)
{
result = m;
stub_manager_int_addref(result);
break;
}
}
@ -108,6 +142,40 @@ struct stub_manager *get_stub_manager_from_object(OXID oxid, void *object)
return result;
}
/* increments the internal refcount */
ULONG stub_manager_int_addref(struct stub_manager *This)
{
ULONG refs;
EnterCriticalSection(&This->apt->cs);
refs = ++This->refs;
LeaveCriticalSection(&This->apt->cs);
TRACE("before %ld\n", refs - 1);
return refs;
}
/* decrements the internal refcount */
ULONG stub_manager_int_release(struct stub_manager *This)
{
ULONG refs;
APARTMENT *apt = This->apt;
EnterCriticalSection(&apt->cs);
refs = --This->refs;
TRACE("after %ld\n", refs);
if (!refs)
stub_manager_delete(This);
LeaveCriticalSection(&apt->cs);
return refs;
}
/* gets the stub manager associated with an object id - caller must call
* release on the stub manager when it is no longer needed */
struct stub_manager *get_stub_manager(OXID oxid, OID oid)
{
struct stub_manager *result = NULL;
@ -128,6 +196,7 @@ struct stub_manager *get_stub_manager(OXID oxid, OID oid)
if (m->oid == oid)
{
result = m;
stub_manager_int_addref(result);
break;
}
}
@ -140,59 +209,30 @@ struct stub_manager *get_stub_manager(OXID oxid, OID oid)
return result;
}
/* add some external references (ie from a client that demarshalled an ifptr) */
int stub_manager_ref(struct stub_manager *m, int refs)
/* add some external references (ie from a client that unmarshaled an ifptr) */
ULONG stub_manager_ext_addref(struct stub_manager *m, ULONG refs)
{
int rc = InterlockedExchangeAdd(&m->refcount, refs) + refs;
TRACE("added %d refs to %p (oid %s), rc is now %d\n", refs, m, wine_dbgstr_longlong(m->oid), rc);
ULONG rc = InterlockedExchangeAdd(&m->extrefs, refs) + refs;
TRACE("added %lu refs to %p (oid %s), rc is now %lu\n", refs, m, wine_dbgstr_longlong(m->oid), rc);
return rc;
}
/* remove some external references */
int stub_manager_unref(struct stub_manager *m, int refs)
ULONG stub_manager_ext_release(struct stub_manager *m, ULONG refs)
{
int rc = InterlockedExchangeAdd(&m->refcount, -refs) - refs;
TRACE("removed %d refs from %p (oid %s), rc is now %d\n", refs, m, wine_dbgstr_longlong(m->oid), rc);
ULONG rc = InterlockedExchangeAdd(&m->extrefs, -refs) - refs;
TRACE("removed %lu refs from %p (oid %s), rc is now %lu\n", refs, m, wine_dbgstr_longlong(m->oid), rc);
if (rc == 0)
{
TRACE("destroying %p (oid=%s)\n", m, wine_dbgstr_longlong(m->oid));
stub_manager_int_release(m);
EnterCriticalSection(&m->apt->cs);
list_remove(&m->entry);
LeaveCriticalSection(&m->apt->cs);
/* table strong and normal marshals have a ref on us, so we
* can't die while they are outstanding unless the app does
* something weird like explicitly killing us (how?)
*/
EnterCriticalSection(&m->lock);
if (!list_empty(&m->ifstubs))
{
ERR("PANIC: Stub manager %s is being destroyed with outstanding interface stubs\n", wine_dbgstr_longlong(m->oid));
/* assert( FALSE ); */
/* fixme: this will happen sometimes until we do proper lifecycle management via IRemUnknown */
}
/* fixme: the lifecycle of table-weak marshals is not
* currently understood. results of testing against dcom98
* appear to contradict Essential COM -m
*/
LeaveCriticalSection(&m->lock);
IUnknown_Release(m->object);
HeapFree(GetProcessHeap(), 0, m);
}
return refs;
return rc;
}
static struct ifstub *stub_manager_ipid_to_ifstub(struct stub_manager *m, IPID *ipid)
static struct ifstub *stub_manager_ipid_to_ifstub(struct stub_manager *m, const IPID *ipid)
{
struct list *cursor;
struct ifstub *result = NULL;
@ -213,7 +253,7 @@ static struct ifstub *stub_manager_ipid_to_ifstub(struct stub_manager *m, IPID *
return result;
}
IRpcStubBuffer *stub_manager_ipid_to_stubbuffer(struct stub_manager *m, IPID *ipid)
IRpcStubBuffer *stub_manager_ipid_to_stubbuffer(struct stub_manager *m, const IPID *ipid)
{
struct ifstub *ifstub = stub_manager_ipid_to_ifstub(m, ipid);
@ -239,7 +279,7 @@ struct ifstub *stub_manager_new_ifstub(struct stub_manager *m, IRpcStubBuffer *s
stub->table = tablemarshal;
stub->iid = *iid;
stub->ipid = *iid; /* FIXME: should be globally unique */
EnterCriticalSection(&m->lock);
list_add_head(&m->ifstubs, &stub->entry);
LeaveCriticalSection(&m->lock);
@ -247,28 +287,14 @@ struct ifstub *stub_manager_new_ifstub(struct stub_manager *m, IRpcStubBuffer *s
return stub;
}
/* fixme: should ifstubs be refcounted? iid should be ipid */
void stub_manager_delete_ifstub(struct stub_manager *m, IPID *ipid)
static void stub_manager_delete_ifstub(struct stub_manager *m, struct ifstub *ifstub)
{
struct ifstub *ifstub;
TRACE("m=%p, m->oid=%s, ipid=%s\n", m, wine_dbgstr_longlong(m->oid), debugstr_guid(&ifstub->ipid));
list_remove(&ifstub->entry);
IUnknown_Release(ifstub->stubbuffer);
IUnknown_Release(ifstub->iface);
TRACE("m=%p, m->oid=%s, ipid=%s\n", m, wine_dbgstr_longlong(m->oid), debugstr_guid(ipid));
EnterCriticalSection(&m->lock);
if ((ifstub = stub_manager_ipid_to_ifstub(m, ipid)))
{
list_remove(&ifstub->entry);
IUnknown_Release(ifstub->stubbuffer);
IUnknown_Release(ifstub->iface);
HeapFree(GetProcessHeap(), 0, ifstub);
}
else
{
WARN("could not map ipid %s to ifstub\n", debugstr_guid(ipid));
}
LeaveCriticalSection(&m->lock);
HeapFree(GetProcessHeap(), 0, ifstub);
}