一种注册表沙箱的思路、实现——研究Reactos中注册表函数的实现2

NTSTATUS OriCreateNestedKey(
    PHANDLE pKeyHandle,
    POBJECT_ATTRIBUTES ObjectAttributes,
    PUNICODE_STRING ClassString,
    DWORD dwOptions,
    REGSAM samDesired,
    DWORD *lpdwDisposition )
{
    UNICODE_STRING LocalKeyName;
    NTSTATUS lRes = STATUS_INVALID_PARAMETER;
  
    do {
        if ( NULL == ObjectAttributes || NULL == ObjectAttributes->ObjectName ) {
            break;
        }

        lRes = RtlCreateUnicodeString_( &LocalKeyName, ObjectAttributes->ObjectName->Buffer );
        CHECKRESULT(lRes);

        lRes = GETORIFUNC(CreateKey)( pKeyHandle, samDesired,
            ObjectAttributes, 0, ClassString, dwOptions, (PULONG)lpdwDisposition );

        if ( STATUS_OBJECT_NAME_NOT_FOUND != lRes ) {
            return lRes;
        }

        OBJECT_ATTRIBUTES LocalObjectAttributes;
        RtlCopyMemory( &LocalObjectAttributes, ObjectAttributes, sizeof(OBJECT_ATTRIBUTES));

        LocalObjectAttributes.ObjectName = &LocalKeyName;
        ULONG FullNameLength = LocalKeyName.Length / sizeof(WCHAR);

        HANDLE LocalKeyHandle = NULL;

        PWCHAR Ptr = NULL;
        ULONG Disposition = 0;

        // 通过将\\改成结尾符，逐个去掉最后一个键名，查看什么路径的注册表键存在
        while ( STATUS_OBJECT_NAME_NOT_FOUND == lRes ) {
            Ptr = wcsrchr(LocalKeyName.Buffer, '\\');
            if ( NULL == Ptr || Ptr == LocalKeyName.Buffer ) {
                lRes = STATUS_UNSUCCESSFUL;
                break;
            }

            // 通过将\\改成结尾符，通过长度去掉键名
            *Ptr = (WCHAR)0;
            LocalKeyName.Length = wcslen(LocalKeyName.Buffer) * sizeof(WCHAR);

            lRes = GETORIFUNC(CreateKey)( &LocalKeyHandle, KEY_CREATE_SUB_KEY,
                &LocalObjectAttributes, 0, NULL, 0, &Disposition );
        }

        CHECKRESULT(lRes);

        // 通过将结尾符改成\\，重新拼接上键名，逐个创建键
        ULONG Length = wcslen(LocalKeyName.Buffer);
        while ( TRUE ) {
            if ( NULL != LocalKeyHandle ) {
                GETORIFUNC(Close) (LocalKeyHandle);
            }

            // 通过将结尾符改成\\，重新拼接上键名
            LocalKeyName.Buffer[Length] = L'\\';
            Length = wcslen (LocalKeyName.Buffer);
            LocalKeyName.Length = Length * sizeof(WCHAR);

            if ( Length == FullNameLength ) {
                // 如果已经拼接回以前的键名了，则执行完后就退出
                lRes = GETORIFUNC(CreateKey)( pKeyHandle, samDesired,
                    ObjectAttributes, 0, ClassString, dwOptions, (PULONG)lpdwDisposition);
                break;
            }

            // 创建祖宗键
            lRes = GETORIFUNC(CreateKey)( &LocalKeyHandle, KEY_CREATE_SUB_KEY,
                &LocalObjectAttributes, 0, NULL, 0, &Disposition);

            if ( NT_FAILED(lRes) ) {
                break;
            }
        }
    } while (0);
    RtlFreeUnicodeString_(&LocalKeyName);
    return lRes;
}