function TSelectSetupDirFrm.DefUsrSetupAbilities: boolean;

var DirAcl: _ACL; SecurityDescriptor: pointer;

    UsrName: string; UsrSid: pointer; UsrTrustee: _TRUSTEE_A;

    AccessRights: cardinal;

  SecurityDescriptor := nil; Result := false;

  if GetNamedSecurityInfo(PChar(FolderField.Text),

         SE_FILE_OBJECT, DACL_SECURITY_INFORMATION,

         nil, nil, @DirAcl, nil, SecurityDescriptor) = ERROR_SUCCESS then begin

    UsrName := DefUsrName;

    UsrSid := DefUsrSid(UsrName);

    if UsrSid <> nil then begin

      UsrTrustee.pMultipleTrustee := nil;

      UsrTrustee.MultipleTrusteeOperation := NO_MULTIPLE_TRUSTEE;

      UsrTrustee.TrusteeForm := TRUSTEE_IS_SID;

      UsrTrustee.TrusteeType := TRUSTEE_IS_USER;

      UsrTrustee.ptstrName := UsrSid;

      //Ошибка выходит здесь

      if GetEffectiveRightsFromAcl(DirAcl, UsrTrustee, AccessRights) = ERROR_SUCCESS then begin

        Result := (AccessRights >= GENERIC_ALL);

      end;

      FreeMem(UsrSid);

    end;

  end;

  if SecurityDescriptor <> nil then LocalFree(HLOCAL(SecurityDescriptor));

end;

 

 

function TSelectSetupDirFrm.DefUsrSetupAbilities: boolean;

  ...; AclPtr: PACL;

  ...;

  if AclPtr = nil then begin

    ShowMessage('AclPtr = nil');

    Result := false; Exit;

  end;

  if not IsValidAcl(AclPtr^) then begin

    ShowMessage('ACL not valid');

    Result := false; Exit;

  end;

  ...;

  if GetEffectiveRightsFromAcl(AclPtr^, UsrTrustee, AccessRights) = ERROR_SUCCESS then begin

    Result := (AccessRights >= GENERIC_ALL);

  end

  else Result := false;

  ...;

end;