Title: How to use the AdjustTokenPrivileges function to enable a privilege (NT)
Question: For some functions you need to get the right privileges
on a Windows NT machine.
(e.g: To shut down or restart windows with ExitWindowsEx or
to change the system time)
Answer:
The following code provides a procedure to adjust the privileges.
The AdjustTokenPrivileges() function enables or disables privileges
in the specified access token.
// NT Defined Privileges from winnt.h
const
SE_CREATE_TOKEN_NAME = 'SeCreateTokenPrivilege';
SE_ASSIGNPRIMARYTOKEN_NAME = 'SeAssignPrimaryTokenPrivilege';
SE_LOCK_MEMORY_NAME = 'SeLockMemoryPrivilege';
SE_INCREASE_QUOTA_NAME = 'SeIncreaseQuotaPrivilege';
SE_UNSOLICITED_INPUT_NAME = 'SeUnsolicitedInputPrivilege';
SE_MACHINE_ACCOUNT_NAME = 'SeMachineAccountPrivilege';
SE_TCB_NAME = 'SeTcbPrivilege';
SE_SECURITY_NAME = 'SeSecurityPrivilege';
SE_TAKE_OWNERSHIP_NAME = 'SeTakeOwnershipPrivilege';
SE_LOAD_DRIVER_NAME = 'SeLoadDriverPrivilege';
SE_SYSTEM_PROFILE_NAME = 'SeSystemProfilePrivilege';
SE_SYSTEMTIME_NAME = 'SeSystemtimePrivilege';
SE_PROF_SINGLE_PROCESS_NAME = 'SeProfileSingleProcessPrivilege';
SE_INC_BASE_PRIORITY_NAME = 'SeIncreaseBasePriorityPrivilege';
SE_CREATE_PAGEFILE_NAME = 'SeCreatePagefilePrivilege';
SE_CREATE_PERMANENT_NAME = 'SeCreatePermanentPrivilege';
SE_BACKUP_NAME = 'SeBackupPrivilege';
SE_RESTORE_NAME = 'SeRestorePrivilege';
SE_SHUTDOWN_NAME = 'SeShutdownPrivilege';
SE_DEBUG_NAME = 'SeDebugPrivilege';
SE_AUDIT_NAME = 'SeAuditPrivilege';
SE_SYSTEM_ENVIRONMENT_NAME = 'SeSystemEnvironmentPrivilege';
SE_CHANGE_NOTIFY_NAME = 'SeChangeNotifyPrivilege';
SE_REMOTE_SHUTDOWN_NAME = 'SeRemoteShutdownPrivilege';
SE_UNDOCK_NAME = 'SeUndockPrivilege';
SE_SYNC_AGENT_NAME = 'SeSyncAgentPrivilege';
SE_ENABLE_DELEGATION_NAME = 'SeEnableDelegationPrivilege';
SE_MANAGE_VOLUME_NAME = 'SeManageVolumePrivilege';
// Enables or disables privileges depending on the bEnabled value
function NTSetPrivilege(sPrivilege: string; bEnabled: Boolean): Boolean;
var
hToken: THandle;
TokenPriv: TOKEN_PRIVILEGES;
PrevTokenPriv: TOKEN_PRIVILEGES;
ReturnLength: Cardinal;
begin
Result := True;
// Only for Windows NT/2000/XP and later.
if not (Win32Platform = VER_PLATFORM_WIN32_NT) then Exit;
Result := False;
// obtain the processes token
if OpenProcessToken(GetCurrentProcess(),
TOKEN_ADJUST_PRIVILEGES or TOKEN_QUERY, hToken) then
begin
try
// Get the locally unique identifier (LUID) .
if LookupPrivilegeValue(nil, PChar(sPrivilege),
TokenPriv.Privileges[0].Luid) then
begin
TokenPriv.PrivilegeCount := 1; // one privilege to set
case bEnabled of
True: TokenPriv.Privileges[0].Attributes := SE_PRIVILEGE_ENABLED;
False: TokenPriv.Privileges[0].Attributes := 0;
end;
ReturnLength := 0; // replaces a var parameter
PrevTokenPriv := TokenPriv;
// enable or disable the privilege
AdjustTokenPrivileges(hToken, False, TokenPriv, SizeOf(PrevTokenPriv),
PrevTokenPriv, ReturnLength);
end;
finally
CloseHandle(hToken);
end;
end;
// test the return value of AdjustTokenPrivileges.
Result := GetLastError = ERROR_SUCCESS;
if not Result then
raise Exception.Create(SysErrorMessage(GetLastError));
end;