diff --git a/dlls/ntdll/ntdll_misc.h b/dlls/ntdll/ntdll_misc.h
index 6683daa1927..5e4c39e8bd6 100644
--- a/dlls/ntdll/ntdll_misc.h
+++ b/dlls/ntdll/ntdll_misc.h
@@ -99,6 +99,7 @@ extern int server_get_unix_fd( HANDLE handle, unsigned int access, int *unix_fd,
 extern int server_pipe( int fd[2] ) DECLSPEC_HIDDEN;
 extern NTSTATUS alloc_object_attributes( const OBJECT_ATTRIBUTES *attr, struct object_attributes **ret,
                                          data_size_t *ret_len ) DECLSPEC_HIDDEN;
+extern NTSTATUS validate_open_object_attributes( const OBJECT_ATTRIBUTES *attr ) DECLSPEC_HIDDEN;
 
 /* module handling */
 extern LIST_ENTRY tls_links DECLSPEC_HIDDEN;
diff --git a/dlls/ntdll/om.c b/dlls/ntdll/om.c
index 4fbb973a2f3..7aa2fea06bf 100644
--- a/dlls/ntdll/om.c
+++ b/dlls/ntdll/om.c
@@ -429,34 +429,24 @@ NTSTATUS WINAPI NtClose( HANDLE Handle )
  *  Success: ERROR_SUCCESS.
  *  Failure: An NTSTATUS error code.
  */
-NTSTATUS WINAPI NtOpenDirectoryObject(PHANDLE DirectoryHandle, ACCESS_MASK DesiredAccess,
-                                      POBJECT_ATTRIBUTES ObjectAttributes)
+NTSTATUS WINAPI NtOpenDirectoryObject( HANDLE *handle, ACCESS_MASK access, const OBJECT_ATTRIBUTES *attr)
 {
     NTSTATUS ret;
 
-    if (!DirectoryHandle) return STATUS_ACCESS_VIOLATION;
-    if (!ObjectAttributes) return STATUS_INVALID_PARAMETER;
-    TRACE("(%p,0x%08x,%s)\n", DirectoryHandle, DesiredAccess, debugstr_ObjectAttributes(ObjectAttributes));
-    /* Have to test it here because server won't know difference between
-     * ObjectName == NULL and ObjectName == "" */
-    if (!ObjectAttributes->ObjectName)
-    {
-        if (ObjectAttributes->RootDirectory)
-            return STATUS_OBJECT_NAME_INVALID;
-        else
-            return STATUS_OBJECT_PATH_SYNTAX_BAD;
-    }
+    if (!handle) return STATUS_ACCESS_VIOLATION;
+    if ((ret = validate_open_object_attributes( attr ))) return ret;
+
+    TRACE("(%p,0x%08x,%s)\n", handle, access, debugstr_ObjectAttributes(attr));
 
     SERVER_START_REQ(open_directory)
     {
-        req->access = DesiredAccess;
-        req->attributes = ObjectAttributes->Attributes;
-        req->rootdir = wine_server_obj_handle( ObjectAttributes->RootDirectory );
-        if (ObjectAttributes->ObjectName)
-            wine_server_add_data(req, ObjectAttributes->ObjectName->Buffer,
-                                 ObjectAttributes->ObjectName->Length);
+        req->access     = access;
+        req->attributes = attr->Attributes;
+        req->rootdir    = wine_server_obj_handle( attr->RootDirectory );
+        if (attr->ObjectName)
+            wine_server_add_data( req, attr->ObjectName->Buffer, attr->ObjectName->Length );
         ret = wine_server_call( req );
-        *DirectoryHandle = wine_server_ptr_handle( reply->handle );
+        *handle = wine_server_ptr_handle( reply->handle );
     }
     SERVER_END_REQ;
     return ret;
@@ -586,34 +576,25 @@ NTSTATUS WINAPI NtQueryDirectoryObject(HANDLE handle, PDIRECTORY_BASIC_INFORMATI
  *  Success: ERROR_SUCCESS.
  *  Failure: An NTSTATUS error code.
  */
-NTSTATUS WINAPI NtOpenSymbolicLinkObject(OUT PHANDLE LinkHandle, IN ACCESS_MASK DesiredAccess,
-                                         IN POBJECT_ATTRIBUTES ObjectAttributes)
+NTSTATUS WINAPI NtOpenSymbolicLinkObject( HANDLE *handle, ACCESS_MASK access,
+                                          const OBJECT_ATTRIBUTES *attr)
 {
     NTSTATUS ret;
-    TRACE("(%p,0x%08x,%s)\n",LinkHandle, DesiredAccess, debugstr_ObjectAttributes(ObjectAttributes));
 
-    if (!LinkHandle) return STATUS_ACCESS_VIOLATION;
-    if (!ObjectAttributes) return STATUS_INVALID_PARAMETER;
-    /* Have to test it here because server won't know difference between
-     * ObjectName == NULL and ObjectName == "" */
-    if (!ObjectAttributes->ObjectName)
-    {
-        if (ObjectAttributes->RootDirectory)
-            return STATUS_OBJECT_NAME_INVALID;
-        else
-            return STATUS_OBJECT_PATH_SYNTAX_BAD;
-    }
+    TRACE("(%p,0x%08x,%s)\n", handle, access, debugstr_ObjectAttributes(attr));
+
+    if (!handle) return STATUS_ACCESS_VIOLATION;
+    if ((ret = validate_open_object_attributes( attr ))) return ret;
 
     SERVER_START_REQ(open_symlink)
     {
-        req->access = DesiredAccess;
-        req->attributes = ObjectAttributes->Attributes;
-        req->rootdir = wine_server_obj_handle( ObjectAttributes->RootDirectory );
-        if (ObjectAttributes->ObjectName)
-            wine_server_add_data(req, ObjectAttributes->ObjectName->Buffer,
-                                 ObjectAttributes->ObjectName->Length);
+        req->access     = access;
+        req->attributes = attr->Attributes;
+        req->rootdir    = wine_server_obj_handle( attr->RootDirectory );
+        if (attr->ObjectName)
+            wine_server_add_data( req, attr->ObjectName->Buffer, attr->ObjectName->Length );
         ret = wine_server_call( req );
-        *LinkHandle = wine_server_ptr_handle( reply->handle );
+        *handle = wine_server_ptr_handle( reply->handle );
     }
     SERVER_END_REQ;
     return ret;
diff --git a/dlls/ntdll/reg.c b/dlls/ntdll/reg.c
index c6eb28d1f77..bf786f48b80 100644
--- a/dlls/ntdll/reg.c
+++ b/dlls/ntdll/reg.c
@@ -130,6 +130,8 @@ NTSTATUS WINAPI NtOpenKeyEx( PHANDLE retkey, ACCESS_MASK access, const OBJECT_AT
 
     if (!retkey || !attr || !attr->ObjectName) return STATUS_ACCESS_VIOLATION;
     if (attr->Length > sizeof(OBJECT_ATTRIBUTES)) return STATUS_INVALID_PARAMETER;
+    if ((ret = validate_open_object_attributes( attr ))) return ret;
+
     TRACE( "(%p,%s,%x,%p)\n", attr->RootDirectory,
            debugstr_us(attr->ObjectName), access, retkey );
     if (options)
diff --git a/dlls/ntdll/sync.c b/dlls/ntdll/sync.c
index e63758ebedd..aa58442700d 100644
--- a/dlls/ntdll/sync.c
+++ b/dlls/ntdll/sync.c
@@ -151,6 +151,19 @@ NTSTATUS alloc_object_attributes( const OBJECT_ATTRIBUTES *attr, struct object_a
     return STATUS_SUCCESS;
 }
 
+NTSTATUS validate_open_object_attributes( const OBJECT_ATTRIBUTES *attr )
+{
+    if (!attr) return STATUS_INVALID_PARAMETER;
+
+    if (attr->ObjectName)
+    {
+        if (attr->ObjectName->Length & (sizeof(WCHAR) - 1)) return STATUS_OBJECT_NAME_INVALID;
+    }
+    else if (attr->RootDirectory) return STATUS_OBJECT_NAME_INVALID;
+
+    return STATUS_SUCCESS;
+}
+
 /*
  *	Semaphores
  */
@@ -191,21 +204,21 @@ NTSTATUS WINAPI NtCreateSemaphore( OUT PHANDLE SemaphoreHandle,
 /******************************************************************************
  *  NtOpenSemaphore (NTDLL.@)
  */
-NTSTATUS WINAPI NtOpenSemaphore( OUT PHANDLE SemaphoreHandle,
-                                 IN ACCESS_MASK access,
-                                 IN const OBJECT_ATTRIBUTES *attr )
+NTSTATUS WINAPI NtOpenSemaphore( HANDLE *handle, ACCESS_MASK access, const OBJECT_ATTRIBUTES *attr )
 {
-    DWORD len = attr && attr->ObjectName ? attr->ObjectName->Length : 0;
     NTSTATUS ret;
 
+    if ((ret = validate_open_object_attributes( attr ))) return ret;
+
     SERVER_START_REQ( open_semaphore )
     {
-        req->access  = access;
-        req->attributes = (attr) ? attr->Attributes : 0;
-        req->rootdir = wine_server_obj_handle( attr ? attr->RootDirectory : 0 );
-        if (len) wine_server_add_data( req, attr->ObjectName->Buffer, len );
+        req->access     = access;
+        req->attributes = attr->Attributes;
+        req->rootdir    = wine_server_obj_handle( attr->RootDirectory );
+        if (attr->ObjectName)
+            wine_server_add_data( req, attr->ObjectName->Buffer, attr->ObjectName->Length );
         ret = wine_server_call( req );
-        *SemaphoreHandle = wine_server_ptr_handle( reply->handle );
+        *handle = wine_server_ptr_handle( reply->handle );
     }
     SERVER_END_REQ;
     return ret;
@@ -298,22 +311,21 @@ NTSTATUS WINAPI NtCreateEvent( PHANDLE EventHandle, ACCESS_MASK DesiredAccess,
  *  NtOpenEvent (NTDLL.@)
  *  ZwOpenEvent (NTDLL.@)
  */
-NTSTATUS WINAPI NtOpenEvent(
-	OUT PHANDLE EventHandle,
-	IN ACCESS_MASK DesiredAccess,
-	IN const OBJECT_ATTRIBUTES *attr )
+NTSTATUS WINAPI NtOpenEvent( HANDLE *handle, ACCESS_MASK access, const OBJECT_ATTRIBUTES *attr )
 {
-    DWORD len = attr && attr->ObjectName ? attr->ObjectName->Length : 0;
     NTSTATUS ret;
 
+    if ((ret = validate_open_object_attributes( attr ))) return ret;
+
     SERVER_START_REQ( open_event )
     {
-        req->access  = DesiredAccess;
-        req->attributes = (attr) ? attr->Attributes : 0;
-        req->rootdir = wine_server_obj_handle( attr ? attr->RootDirectory : 0 );
-        if (len) wine_server_add_data( req, attr->ObjectName->Buffer, len );
+        req->access     = access;
+        req->attributes = attr->Attributes;
+        req->rootdir    = wine_server_obj_handle( attr->RootDirectory );
+        if (attr->ObjectName)
+            wine_server_add_data( req, attr->ObjectName->Buffer, attr->ObjectName->Length );
         ret = wine_server_call( req );
-        *EventHandle = wine_server_ptr_handle( reply->handle );
+        *handle = wine_server_ptr_handle( reply->handle );
     }
     SERVER_END_REQ;
     return ret;
@@ -464,21 +476,21 @@ NTSTATUS WINAPI NtCreateMutant(OUT HANDLE* MutantHandle,
  *		NtOpenMutant				[NTDLL.@]
  *		ZwOpenMutant				[NTDLL.@]
  */
-NTSTATUS WINAPI NtOpenMutant(OUT HANDLE* MutantHandle, 
-                             IN ACCESS_MASK access, 
-                             IN const OBJECT_ATTRIBUTES* attr )
+NTSTATUS WINAPI NtOpenMutant( HANDLE *handle, ACCESS_MASK access, const OBJECT_ATTRIBUTES *attr )
 {
     NTSTATUS    status;
-    DWORD       len = attr && attr->ObjectName ? attr->ObjectName->Length : 0;
+
+    if ((status = validate_open_object_attributes( attr ))) return status;
 
     SERVER_START_REQ( open_mutex )
     {
         req->access  = access;
-        req->attributes = (attr) ? attr->Attributes : 0;
-        req->rootdir = wine_server_obj_handle( attr ? attr->RootDirectory : 0 );
-        if (len) wine_server_add_data( req, attr->ObjectName->Buffer, len );
+        req->attributes = attr->Attributes;
+        req->rootdir = wine_server_obj_handle( attr->RootDirectory );
+        if (attr->ObjectName)
+            wine_server_add_data( req, attr->ObjectName->Buffer, attr->ObjectName->Length );
         status = wine_server_call( req );
-        *MutantHandle = wine_server_ptr_handle( reply->handle );
+        *handle = wine_server_ptr_handle( reply->handle );
     }
     SERVER_END_REQ;
     return status;
@@ -550,17 +562,19 @@ NTSTATUS WINAPI NtCreateJobObject( PHANDLE handle, ACCESS_MASK access, const OBJ
  *              NtOpenJobObject   [NTDLL.@]
  *              ZwOpenJobObject   [NTDLL.@]
  */
-NTSTATUS WINAPI NtOpenJobObject( PHANDLE handle, ACCESS_MASK access, const OBJECT_ATTRIBUTES *attr )
+NTSTATUS WINAPI NtOpenJobObject( HANDLE *handle, ACCESS_MASK access, const OBJECT_ATTRIBUTES *attr )
 {
-    DWORD len = attr && attr->ObjectName ? attr->ObjectName->Length : 0;
     NTSTATUS ret;
 
+    if ((ret = validate_open_object_attributes( attr ))) return ret;
+
     SERVER_START_REQ( open_job )
     {
-        req->access  = access;
-        req->attributes = attr ? attr->Attributes : 0;
-        req->rootdir = wine_server_obj_handle( attr ? attr->RootDirectory : 0 );
-        if (len) wine_server_add_data( req, attr->ObjectName->Buffer, len );
+        req->access     = access;
+        req->attributes = attr->Attributes;
+        req->rootdir    = wine_server_obj_handle( attr->RootDirectory );
+        if (attr->ObjectName)
+            wine_server_add_data( req, attr->ObjectName->Buffer, attr->ObjectName->Length );
         ret = wine_server_call( req );
         *handle = wine_server_ptr_handle( reply->handle );
     }
@@ -780,19 +794,19 @@ NTSTATUS WINAPI NtCreateTimer(OUT HANDLE *handle,
  *		NtOpenTimer				[NTDLL.@]
  *		ZwOpenTimer				[NTDLL.@]
  */
-NTSTATUS WINAPI NtOpenTimer(OUT PHANDLE handle,
-                            IN ACCESS_MASK access,
-                            IN const OBJECT_ATTRIBUTES* attr )
+NTSTATUS WINAPI NtOpenTimer( HANDLE *handle, ACCESS_MASK access, const OBJECT_ATTRIBUTES *attr )
 {
-    DWORD       len = (attr && attr->ObjectName) ? attr->ObjectName->Length : 0;
-    NTSTATUS    status;
+    NTSTATUS status;
+
+    if ((status = validate_open_object_attributes( attr ))) return status;
 
     SERVER_START_REQ( open_timer )
     {
-        req->access  = access;
-        req->attributes = (attr) ? attr->Attributes : 0;
-        req->rootdir = wine_server_obj_handle( attr ? attr->RootDirectory : 0 );
-        if (len) wine_server_add_data( req, attr->ObjectName->Buffer, len );
+        req->access     = access;
+        req->attributes = attr->Attributes;
+        req->rootdir    = wine_server_obj_handle( attr ? attr->RootDirectory : 0 );
+        if (attr->ObjectName)
+            wine_server_add_data( req, attr->ObjectName->Buffer, attr->ObjectName->Length );
         status = wine_server_call( req );
         *handle = wine_server_ptr_handle( reply->handle );
     }
@@ -1092,15 +1106,17 @@ NTSTATUS WINAPI NtCreateKeyedEvent( HANDLE *handle, ACCESS_MASK access,
  */
 NTSTATUS WINAPI NtOpenKeyedEvent( HANDLE *handle, ACCESS_MASK access, const OBJECT_ATTRIBUTES *attr )
 {
-    DWORD len = attr && attr->ObjectName ? attr->ObjectName->Length : 0;
     NTSTATUS ret;
 
+    if ((ret = validate_open_object_attributes( attr ))) return ret;
+
     SERVER_START_REQ( open_keyed_event )
     {
-        req->access  = access;
-        req->attributes = attr ? attr->Attributes : 0;
-        req->rootdir = wine_server_obj_handle( attr ? attr->RootDirectory : 0 );
-        if (len) wine_server_add_data( req, attr->ObjectName->Buffer, len );
+        req->access     = access;
+        req->attributes = attr->Attributes;
+        req->rootdir    = wine_server_obj_handle( attr->RootDirectory );
+        if (attr->ObjectName)
+            wine_server_add_data( req, attr->ObjectName->Buffer, attr->ObjectName->Length );
         ret = wine_server_call( req );
         *handle = wine_server_ptr_handle( reply->handle );
     }
@@ -1275,24 +1291,22 @@ NTSTATUS WINAPI NtRemoveIoCompletion( HANDLE CompletionPort, PULONG_PTR Completi
  *      ObjectAttributes   [I] completion object name
  *
  */
-NTSTATUS WINAPI NtOpenIoCompletion( PHANDLE CompletionPort, ACCESS_MASK DesiredAccess,
-                                    POBJECT_ATTRIBUTES ObjectAttributes )
+NTSTATUS WINAPI NtOpenIoCompletion( HANDLE *handle, ACCESS_MASK access, const OBJECT_ATTRIBUTES *attr )
 {
     NTSTATUS status;
 
-    TRACE("(%p, 0x%x, %p)\n", CompletionPort, DesiredAccess, ObjectAttributes);
-
-    if (!CompletionPort || !ObjectAttributes || !ObjectAttributes->ObjectName)
-        return STATUS_INVALID_PARAMETER;
+    if (!handle) return STATUS_INVALID_PARAMETER;
+    if ((status = validate_open_object_attributes( attr ))) return status;
 
     SERVER_START_REQ( open_completion )
     {
-        req->access     = DesiredAccess;
-        req->rootdir    = wine_server_obj_handle( ObjectAttributes->RootDirectory );
-        wine_server_add_data( req, ObjectAttributes->ObjectName->Buffer,
-                                   ObjectAttributes->ObjectName->Length );
-        if (!(status = wine_server_call( req )))
-            *CompletionPort = wine_server_ptr_handle( reply->handle );
+        req->access     = access;
+        req->attributes = attr->Attributes;
+        req->rootdir    = wine_server_obj_handle( attr->RootDirectory );
+        if (attr->ObjectName)
+            wine_server_add_data( req, attr->ObjectName->Buffer, attr->ObjectName->Length );
+        status = wine_server_call( req );
+        *handle = wine_server_ptr_handle( reply->handle );
     }
     SERVER_END_REQ;
     return status;
diff --git a/dlls/ntdll/tests/om.c b/dlls/ntdll/tests/om.c
index ba14825ebf6..e2593b104de 100644
--- a/dlls/ntdll/tests/om.c
+++ b/dlls/ntdll/tests/om.c
@@ -514,52 +514,42 @@ static void test_name_limits(void)
     status = pNtCreateMutant( &ret, GENERIC_ALL, &attr2, FALSE );
     ok( status == STATUS_OBJECT_NAME_INVALID, "%u: NtCreateMutant failed %x\n", str.Length, status );
     status = pNtOpenMutant( &ret, GENERIC_ALL, &attr2 );
-    todo_wine
     ok( status == STATUS_OBJECT_NAME_INVALID, "%u: NtOpenMutant failed %x\n", str.Length, status );
     status = pNtCreateSemaphore( &ret, GENERIC_ALL, &attr2, 1, 2 );
     ok( status == STATUS_OBJECT_NAME_INVALID, "%u: NtCreateSemaphore failed %x\n", str.Length, status );
     status = pNtOpenSemaphore( &ret, GENERIC_ALL, &attr2 );
-    todo_wine
     ok( status == STATUS_OBJECT_NAME_INVALID, "%u: NtOpenSemaphore failed %x\n", str.Length, status );
     status = pNtCreateEvent( &ret, GENERIC_ALL, &attr2, 1, 0 );
     ok( status == STATUS_OBJECT_NAME_INVALID, "%u: NtCreateEvent failed %x\n", str.Length, status );
     status = pNtOpenEvent( &ret, GENERIC_ALL, &attr2 );
-    todo_wine
     ok( status == STATUS_OBJECT_NAME_INVALID, "%u: NtOpenEvent failed %x\n", str.Length, status );
     status = pNtCreateKeyedEvent( &ret, GENERIC_ALL, &attr2, 0 );
     ok( status == STATUS_OBJECT_NAME_INVALID, "%u: NtCreateKeyedEvent failed %x\n", str.Length, status );
     status = pNtOpenKeyedEvent( &ret, GENERIC_ALL, &attr2 );
-    todo_wine
     ok( status == STATUS_OBJECT_NAME_INVALID, "%u: NtOpenKeyedEvent failed %x\n", str.Length, status );
     status = pNtCreateTimer( &ret, GENERIC_ALL, &attr2, NotificationTimer );
     ok( status == STATUS_OBJECT_NAME_INVALID, "%u: NtCreateTimer failed %x\n", str.Length, status );
     status = pNtOpenTimer( &ret, GENERIC_ALL, &attr2 );
-    todo_wine
     ok( status == STATUS_OBJECT_NAME_INVALID, "%u: NtOpenTimer failed %x\n", str.Length, status );
     status = pNtCreateIoCompletion( &ret, GENERIC_ALL, &attr2, 0 );
     ok( status == STATUS_OBJECT_NAME_INVALID, "%u: NtCreateCompletion failed %x\n", str.Length, status );
     status = pNtOpenIoCompletion( &ret, GENERIC_ALL, &attr2 );
-    todo_wine
     ok( status == STATUS_OBJECT_NAME_INVALID, "%u: NtOpenCompletion failed %x\n", str.Length, status );
     status = pNtCreateJobObject( &ret, GENERIC_ALL, &attr2 );
     ok( status == STATUS_OBJECT_NAME_INVALID, "%u: NtCreateJobObject failed %x\n", str.Length, status );
     status = pNtOpenJobObject( &ret, GENERIC_ALL, &attr2 );
-    todo_wine
     ok( status == STATUS_OBJECT_NAME_INVALID, "%u: NtOpenJobObject failed %x\n", str.Length, status );
     status = pNtCreateDirectoryObject( &ret, GENERIC_ALL, &attr2 );
     ok( status == STATUS_OBJECT_NAME_INVALID, "%u: NtCreateDirectoryObject failed %x\n", str.Length, status );
     status = pNtOpenDirectoryObject( &ret, GENERIC_ALL, &attr2 );
-    todo_wine
     ok( status == STATUS_OBJECT_NAME_INVALID, "%u: NtOpenDirectoryObject failed %x\n", str.Length, status );
     status = pNtCreateSymbolicLinkObject( &ret, GENERIC_ALL, &attr2, &target );
     ok( status == STATUS_OBJECT_NAME_INVALID, "%u: NtCreateSymbolicLinkObject failed %x\n", str.Length, status );
     status = pNtOpenSymbolicLinkObject( &ret, GENERIC_ALL, &attr2 );
-    todo_wine
     ok( status == STATUS_OBJECT_NAME_INVALID, "%u: NtOpenSymbolicLinkObject failed %x\n", str.Length, status );
     status = pNtCreateSection( &ret, SECTION_MAP_WRITE, &attr2, &size, PAGE_READWRITE, SEC_COMMIT, 0 );
     ok( status == STATUS_OBJECT_NAME_INVALID, "%u: NtCreateSection failed %x\n", str.Length, status );
     status = pNtOpenSection( &ret, SECTION_MAP_WRITE, &attr2 );
-    todo_wine
     ok( status == STATUS_OBJECT_NAME_INVALID, "%u: NtOpenSection failed %x\n", str.Length, status );
 
     str.Length = 65532;
@@ -620,7 +610,6 @@ static void test_name_limits(void)
     status = pNtCreateSection( &ret, SECTION_MAP_WRITE, &attr, &size, PAGE_READWRITE, SEC_COMMIT, 0 );
     ok( status == STATUS_SUCCESS, "%u: NtCreateSection failed %x\n", str.Length, status );
     status = pNtOpenSection( &ret2, SECTION_MAP_WRITE, &attr );
-    todo_wine
     ok( status == STATUS_SUCCESS, "%u: NtOpenSection failed %x\n", str.Length, status );
     pNtClose( ret2 );
     pNtClose( ret );
@@ -686,7 +675,6 @@ static void test_name_limits(void)
     ok( status == STATUS_SUCCESS, "NULL: NtCreateMutant failed %x\n", status );
     pNtClose( ret );
     status = pNtOpenMutant( &ret, GENERIC_ALL, &attr2 );
-    todo_wine
     ok( status == STATUS_OBJECT_NAME_INVALID, "NULL: NtOpenMutant failed %x\n", status );
     status = pNtOpenMutant( &ret, GENERIC_ALL, &attr3 );
     ok( status == STATUS_OBJECT_PATH_SYNTAX_BAD, "NULL: NtOpenMutant failed %x\n", status );
@@ -696,7 +684,6 @@ static void test_name_limits(void)
     ok( status == STATUS_SUCCESS, "NULL: NtCreateSemaphore failed %x\n", status );
     pNtClose( ret );
     status = pNtOpenSemaphore( &ret, GENERIC_ALL, &attr2 );
-    todo_wine
     ok( status == STATUS_OBJECT_NAME_INVALID, "NULL: NtOpenSemaphore failed %x\n", status );
     status = pNtOpenSemaphore( &ret, GENERIC_ALL, &attr3 );
     ok( status == STATUS_OBJECT_PATH_SYNTAX_BAD, "NULL: NtOpenSemaphore failed %x\n", status );
@@ -706,7 +693,6 @@ static void test_name_limits(void)
     ok( status == STATUS_SUCCESS, "NULL: NtCreateEvent failed %x\n", status );
     pNtClose( ret );
     status = pNtOpenEvent( &ret, GENERIC_ALL, &attr2 );
-    todo_wine
     ok( status == STATUS_OBJECT_NAME_INVALID, "NULL: NtOpenEvent failed %x\n", status );
     status = pNtOpenEvent( &ret, GENERIC_ALL, &attr3 );
     ok( status == STATUS_OBJECT_PATH_SYNTAX_BAD, "NULL: NtOpenEvent failed %x\n", status );
@@ -716,7 +702,6 @@ static void test_name_limits(void)
     ok( status == STATUS_SUCCESS, "NULL: NtCreateKeyedEvent failed %x\n", status );
     pNtClose( ret );
     status = pNtOpenKeyedEvent( &ret, GENERIC_ALL, &attr2 );
-    todo_wine
     ok( status == STATUS_OBJECT_NAME_INVALID, "NULL: NtOpenKeyedEvent failed %x\n", status );
     status = pNtOpenKeyedEvent( &ret, GENERIC_ALL, &attr3 );
     ok( status == STATUS_OBJECT_PATH_SYNTAX_BAD, "NULL: NtOpenKeyedEvent failed %x\n", status );
@@ -726,7 +711,6 @@ static void test_name_limits(void)
     ok( status == STATUS_SUCCESS, "NULL: NtCreateTimer failed %x\n", status );
     pNtClose( ret );
     status = pNtOpenTimer( &ret, GENERIC_ALL, &attr2 );
-    todo_wine
     ok( status == STATUS_OBJECT_NAME_INVALID, "NULL: NtOpenTimer failed %x\n", status );
     status = pNtOpenTimer( &ret, GENERIC_ALL, &attr3 );
     ok( status == STATUS_OBJECT_PATH_SYNTAX_BAD, "NULL: NtOpenTimer failed %x\n", status );
@@ -736,10 +720,8 @@ static void test_name_limits(void)
     ok( status == STATUS_SUCCESS, "NULL: NtCreateCompletion failed %x\n", status );
     pNtClose( ret );
     status = pNtOpenIoCompletion( &ret, GENERIC_ALL, &attr2 );
-    todo_wine
     ok( status == STATUS_OBJECT_NAME_INVALID, "NULL: NtOpenCompletion failed %x\n", status );
     status = pNtOpenIoCompletion( &ret, GENERIC_ALL, &attr3 );
-    todo_wine
     ok( status == STATUS_OBJECT_PATH_SYNTAX_BAD, "NULL: NtOpenCompletion failed %x\n", status );
     status = pNtCreateJobObject( &ret, GENERIC_ALL, &attr2 );
     ok( status == STATUS_OBJECT_NAME_INVALID, "NULL: NtCreateJobObject failed %x\n", status );
@@ -747,7 +729,6 @@ static void test_name_limits(void)
     ok( status == STATUS_SUCCESS, "NULL: NtCreateJobObject failed %x\n", status );
     pNtClose( ret );
     status = pNtOpenJobObject( &ret, GENERIC_ALL, &attr2 );
-    todo_wine
     ok( status == STATUS_OBJECT_NAME_INVALID, "NULL: NtOpenJobObject failed %x\n", status );
     status = pNtOpenJobObject( &ret, GENERIC_ALL, &attr3 );
     ok( status == STATUS_OBJECT_PATH_SYNTAX_BAD, "NULL: NtOpenJobObject failed %x\n", status );
@@ -775,7 +756,6 @@ static void test_name_limits(void)
     ok( status == STATUS_SUCCESS, "NULL: NtCreateSection failed %x\n", status );
     pNtClose( ret );
     status = pNtOpenSection( &ret, SECTION_MAP_WRITE, &attr2 );
-    todo_wine
     ok( status == STATUS_OBJECT_NAME_INVALID, "NULL: NtOpenSection failed %x\n", status );
     status = pNtOpenSection( &ret, SECTION_MAP_WRITE, &attr3 );
     ok( status == STATUS_OBJECT_PATH_SYNTAX_BAD, "NULL: NtOpenSection failed %x\n", status );
@@ -898,7 +878,6 @@ static void test_name_limits(void)
         pNtClose( ret );
     }
     status = pNtOpenKey( &ret, GENERIC_ALL, &attr );
-    todo_wine
     ok( status == STATUS_OBJECT_NAME_INVALID ||
         status == STATUS_INVALID_PARAMETER ||
         broken( status == STATUS_OBJECT_NAME_NOT_FOUND ), /* wow64 */
diff --git a/dlls/ntdll/virtual.c b/dlls/ntdll/virtual.c
index 81a08cde88d..c57524a55c0 100644
--- a/dlls/ntdll/virtual.c
+++ b/dlls/ntdll/virtual.c
@@ -2498,17 +2498,18 @@ NTSTATUS WINAPI NtCreateSection( HANDLE *handle, ACCESS_MASK access, const OBJEC
 NTSTATUS WINAPI NtOpenSection( HANDLE *handle, ACCESS_MASK access, const OBJECT_ATTRIBUTES *attr )
 {
     NTSTATUS ret;
-    DWORD len = (attr && attr->ObjectName) ? attr->ObjectName->Length : 0;
 
-    if (len > MAX_PATH*sizeof(WCHAR)) return STATUS_NAME_TOO_LONG;
+    if ((ret = validate_open_object_attributes( attr ))) return ret;
 
     SERVER_START_REQ( open_mapping )
     {
-        req->access  = access;
+        req->access     = access;
         req->attributes = attr->Attributes;
-        req->rootdir = wine_server_obj_handle( attr->RootDirectory );
-        wine_server_add_data( req, attr->ObjectName->Buffer, len );
-        if (!(ret = wine_server_call( req ))) *handle = wine_server_ptr_handle( reply->handle );
+        req->rootdir    = wine_server_obj_handle( attr->RootDirectory );
+        if (attr->ObjectName)
+            wine_server_add_data( req, attr->ObjectName->Buffer, attr->ObjectName->Length );
+        ret = wine_server_call( req );
+        *handle = wine_server_ptr_handle( reply->handle );
     }
     SERVER_END_REQ;
     return ret;
diff --git a/include/winternl.h b/include/winternl.h
index 3494c006484..51320f2067c 100644
--- a/include/winternl.h
+++ b/include/winternl.h
@@ -2191,11 +2191,11 @@ NTSYSAPI NTSTATUS  WINAPI NtMapViewOfSection(HANDLE,HANDLE,PVOID*,ULONG,SIZE_T,c
 NTSYSAPI NTSTATUS  WINAPI NtNotifyChangeDirectoryFile(HANDLE,HANDLE,PIO_APC_ROUTINE,PVOID,PIO_STATUS_BLOCK,PVOID,ULONG,ULONG,BOOLEAN);
 NTSYSAPI NTSTATUS  WINAPI NtNotifyChangeKey(HANDLE,HANDLE,PIO_APC_ROUTINE,PVOID,PIO_STATUS_BLOCK,ULONG,BOOLEAN,PVOID,ULONG,BOOLEAN);
 NTSYSAPI NTSTATUS  WINAPI NtNotifyChangeMultipleKeys(HANDLE,ULONG,OBJECT_ATTRIBUTES*,HANDLE,PIO_APC_ROUTINE,PVOID,PIO_STATUS_BLOCK,ULONG,BOOLEAN,PVOID,ULONG,BOOLEAN);
-NTSYSAPI NTSTATUS  WINAPI NtOpenDirectoryObject(PHANDLE,ACCESS_MASK,POBJECT_ATTRIBUTES);
+NTSYSAPI NTSTATUS  WINAPI NtOpenDirectoryObject(PHANDLE,ACCESS_MASK,const OBJECT_ATTRIBUTES*);
 NTSYSAPI NTSTATUS  WINAPI NtOpenEvent(PHANDLE,ACCESS_MASK,const OBJECT_ATTRIBUTES *);
-NTSYSAPI NTSTATUS  WINAPI NtOpenEventPair(PHANDLE,ACCESS_MASK,POBJECT_ATTRIBUTES);
+NTSYSAPI NTSTATUS  WINAPI NtOpenEventPair(PHANDLE,ACCESS_MASK,const OBJECT_ATTRIBUTES*);
 NTSYSAPI NTSTATUS  WINAPI NtOpenFile(PHANDLE,ACCESS_MASK,POBJECT_ATTRIBUTES,PIO_STATUS_BLOCK,ULONG,ULONG);
-NTSYSAPI NTSTATUS  WINAPI NtOpenIoCompletion(PHANDLE,ACCESS_MASK,POBJECT_ATTRIBUTES);
+NTSYSAPI NTSTATUS  WINAPI NtOpenIoCompletion(PHANDLE,ACCESS_MASK,const OBJECT_ATTRIBUTES*);
 NTSYSAPI NTSTATUS  WINAPI NtOpenJobObject(PHANDLE,ACCESS_MASK,const OBJECT_ATTRIBUTES*);
 NTSYSAPI NTSTATUS  WINAPI NtOpenKey(PHANDLE,ACCESS_MASK,const OBJECT_ATTRIBUTES *);
 NTSYSAPI NTSTATUS  WINAPI NtOpenKeyEx(PHANDLE,ACCESS_MASK,const OBJECT_ATTRIBUTES*,ULONG);
@@ -2209,7 +2209,7 @@ NTSYSAPI NTSTATUS  WINAPI NtOpenProcessToken(HANDLE,DWORD,HANDLE *);
 NTSYSAPI NTSTATUS  WINAPI NtOpenProcessTokenEx(HANDLE,DWORD,DWORD,HANDLE *);
 NTSYSAPI NTSTATUS  WINAPI NtOpenSection(HANDLE*,ACCESS_MASK,const OBJECT_ATTRIBUTES*);
 NTSYSAPI NTSTATUS  WINAPI NtOpenSemaphore(PHANDLE,ACCESS_MASK,const OBJECT_ATTRIBUTES*);
-NTSYSAPI NTSTATUS  WINAPI NtOpenSymbolicLinkObject(PHANDLE,ACCESS_MASK,POBJECT_ATTRIBUTES);
+NTSYSAPI NTSTATUS  WINAPI NtOpenSymbolicLinkObject(PHANDLE,ACCESS_MASK,const OBJECT_ATTRIBUTES*);
 NTSYSAPI NTSTATUS  WINAPI NtOpenThread(HANDLE*,ACCESS_MASK,const OBJECT_ATTRIBUTES*,const CLIENT_ID*);
 NTSYSAPI NTSTATUS  WINAPI NtOpenThreadToken(HANDLE,DWORD,BOOLEAN,HANDLE *);
 NTSYSAPI NTSTATUS  WINAPI NtOpenThreadTokenEx(HANDLE,DWORD,BOOLEAN,DWORD,HANDLE *);