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Restricting the Use of Accounts  



Workload schedules often dictate the days and times your system is used to perform specific operations. Depending on the nature of the work performed at your site, you might want to control when certain users are allowed to log in. Use the Authorize utility (AUTHORIZE) to place controls in the login characteristics fields of the UAF record to restrict the days and times a user can log in and to inhibit certain login functions.

The following sections describe how to perform these tasks:

Task Section
Setting day types
Setting Day Types
Restricting logins to specific times
Restricting Logins to Specific Times
Restricting CPU time
Restricting CPU Time
Restricting login functions
Restricting Login Functions
Using login command procedures for restricted or captive accounts
Using Login Command Procedures for Restricted or Captive Accounts
Setting priorities for user processes
Setting Priorities for User Processes

For a detailed description of the qualifiers used to restrict the use of accounts, see the Authorize utility section in the HP OpenVMS System Management Utilities Reference Manual.

Setting Day Types  

You can restrict the use of certain accounts by defining the days of the week as either PRIMARY or SECONDARY, and then assigning login restrictions to these day types. For example, if you define the days Saturday and Sunday as SECONDARY days, then any restrictions you assign to the SECONDARY day type apply to both.

You can assign two types of login restrictions to either day type:

Restriction Description
Time restrictions
Limits logins to specific hours of the day
Function restrictions
Limit types of login

The default user record defines the five weekdays (Monday through Friday) as PRIMARY days, and the two weekend days (Saturday and Sunday) as SECONDARY days.

The way you define days and assign restrictions depends on your site. For example, suppose that on weekdays your system supports a large number of interactive users, but on weekends it is used for certain operations that require dedicated system resources. By assigning restrictions to the SECONDARY day type, you can restrict users from accessing the system during the days defined as SECONDARY. You can change these day type definitions for any account using the following AUTHORIZE qualifier:

/PRIMEDAYS=([NO]day[,...])
The /PRIMEDAYS qualifier uses a list of day names to define the PRIMARY and SECONDARY days of the week. To define a day as a SECONDARY day, use the prefix NO before the day name. Any days you omit from the list take their default value.

Restricting Logins to Specific Times  

By default, there are no restrictions on login hours. You can specify login time restrictions using the following AUTHORIZE qualifiers:

Qualifier Meaning
/[NO]ACCESS
Specifies access hours for all modes of logins
/[NO]DIALUP
Specifies access hours for interactive logins from dialup terminals
/[NO]INTERACTIVE
Specifies access hours for interactive logins from any terminal
/[NO]LOCAL
Specifies access hours for interactive logins from local terminals
/[NO]REMOTE
Specifies access hours for interactive logins from network remote terminals (SET HOST)

Interactive users still logged in when the access time has expired receive the following warning message and have 2 minutes to log out before their processes are terminated by the job controller:

JBC-W-RESTRICT, UAF restricts access at this time, please log out immediately
Note that network connections are treated differently than interactive connections and batch jobs. See the documentation for the network software you are running for information about disconnecting established network connections.

Restricting CPU Time  

OpenVMS Version 7.3 and later enables you to perform class scheduling using the SYSMAN interface.

You can limit the amount of CPU time that a user receives on the system by placing the user into a scheduling class. Each scheduling class is assigned a percentage of the overall CPU time on the system. As the system runs, the set of users in each scheduling class is limited to the percentage of CPU execution time allocated to that class. Users in a scheduling class can get additional CPU time if windfall is enabled for their scheduling class. Enabling windfall allows the system to give a small amount of CPU time to a scheduling class when a CPU is idle and the time alloted to that scheduling class has already been depleted.

To invoke the class scheduler, use the SYSMAN interface. SYSMAN allows you to create, delete, modify, suspend, resume, and display scheduling classes. SYSMAN command: class_schedule describes the SYSMAN command, class_schedule, and its sub-commands.

Table 7   SYSMAN command: class_schedule
Sub-command Function
Add
Creates a new scheduling class
Delete
Deletes a scheduling class
Modify
Modifies the characteristics of a scheduling class
Show
Shows the characteristics of a scheduling class
Suspend
Suspends temporarily a scheduling class
Resume
Resumes a scheduling class

By using a permanent class scheduler, a process is placed into a scheduling class, if appropriate, at process creation time. When a new process is created, it needs to be determined whether this process belongs to a scheduling class. Since to determine this relies upon data in the SYSUAF file, and the Loginout image already has the process' information from this file, Loginout class schedules the process if it determines that the process belongs to a scheduling class.

When you use the SYSMAN command CLASS_SCHEDULE ADD, you can do the following:

For example:

SYSMAN>
CLASS_SCHEDULE ADD MAINCLASS -
_SYSMAN> /ACCOUNT = (ACCTNAME1, ACCTNAME2) -
_SYSMAN> /USERNAME = HOTSHOT -
_SYSMAN> /CPU_LIMIT = (PRIMARY, 08-17=15, SECONDARY, 00-23=30) -
_SYSMAN> /WINDFALL
This example performs the following actions:

Note that you can use the /PRIMEDAYS qualifier to change the primary and secondary days assigned to a scheduling class.

CPU time restrictions created with the class scheduler do not apply to system users (see Understanding Protection Codes).

For more detailed information about the SYSMAN CLASS_SCHEDULE command, see the HP OpenVMS System Management Utilities Reference Manual: M--Z.

Restricting Login Functions  

In addition to specifying hourly login restrictions, you can assign function restrictions to an account by using appropriate keywords with the /FLAGS qualifier in the Authorize utility. By default, there are no restrictions. Options are shown in the following table:

Keyword Meaning
[NO]AUDIT
[Do not] audit all security-relevant actions.
[NO]AUTOLOGIN
[Do not] prevent access except by automatic login when automatic logins are enabled.
[NO]CAPTIVE
[Do not] prevent user from changing any defaults at login (implies DISCTLY).

[Do not] deny user access to the DCL command level.
[NO]DEFCLI
[Do not] prevent user from changing default CLI or CLI tables.
[NO]DISCTLY
[Do not] disable Ctrl/Y interrupts.
[NO]DISFORCE_PWD_CHANGE
[Do not] remove requirement that user must change an expired password at login.
[NO]DISIMAGE
[Do not] prevent user from using the RUN or MCR commands or from executing "foreign" commands.
[NO]DISMAIL
[Do not] prevent mail delivery to the user.
[NO]DISNEWMAIL
[Do not] suppress "New Mail... " announcements.
[NO]DISPWDDIC
[Do not] disable automatic screening of new passwords against a system dictionary.
[NO]DISPWDHIS
[Do not] disable automatic checking of new passwords against list of user's old passwords.
[NO]DISRECONNECT
[Do not] disable automatic reconnection to an existing process when a terminal connection has been interrupted.
[NO]DISREPORT
[Do not] disable reporting of login information (last login date, login failures, and so on).
[NO]DISUSER
[Do not] disable account completely.
[NO]DISWELCOME
[Do not] suppress "Welcome to... " login message.
[NO]GENPWD
[Do not] require user to use generated passwords.
[NO]LOCKPWD
[Do not] prevent user from changing password.
[NO]PWD_EXPIRED
[Do not] mark password as expired.
[NO]PWD2_EXPIRED
[Do not] mark second password as expired.
[NO]RESTRICTED
[Do not] prevent user from changing any defaults at login.

Using Login Command Procedures for Restricted or Captive Accounts  

Using the /LGICMD qualifier with the AUTHORIZE commands ADD, MODIFY, or COPY defines the login procedure for a restricted or captive account. A person logging in to such an account cannot modify the procedure with any of the login qualifiers: /CLI, /DISK, /COMMAND, /NOCOMMAND, /TABLES.

The CAPTIVE and RESTRICTED flags perform the following actions:

Once logged in, a person using a restricted account operates from the DCL level and can access any available software.

A person using a captive account is locked into the application software where access to the DCL level is denied, provided the system manager observes the following practices:

Example

A simple login command procedure for a captive account used for an inventory system might consist of the following commands:

$ DEFINE SYS$DISK DISK$INVENT
$ RUN INVENTORY
$ LOGOUT
The application program INVENTORY assumes control when the user logs in to the account. Assign the CAPTIVE flag to the login flags field of the captive account UAF record by specifying the AUTHORIZE qualifier /FLAGS=CAPTIVE. Maintaining the User Environment shows how to use AUTHORIZE to create a UAF record for a captive account.

Sample Captive Command Procedure is a command procedure for a highly secure captive account, which restricts the user to a very limited set of commands. System managers must be sure to deny the account owner any write access to the login command procedure and its directory. Note also that the security manager would use the AUTHORIZE qualifier /NOINTERACTIVE when establishing this account.

For more information about captive and restricted accounts, see the HP OpenVMS Guide to System Security .
Example 4  Sample Captive Command Procedure  
$ deassign sys$input
$ previous_sysinput == f$logical("SYS$INPUT")
$ on error then goto next_command
$ on control_y then goto next_command
$ set control=(y,t)
$
$next_command:
$ on error then goto next_command
$ on control_y then goto next_command
$
$ if previous_sysinput .nes. f$logical("SYS$INPUT") then deassign sys$input
$ read/end=next_command/prompt="$ " sys$command command
$ command == f$edit(command,"UPCASE,TRIM,COMPRESS")
$ if f$length(command) .eq. 0 then goto next_command
$
$ delete = "delete"$ delete/symbol/local/all
$ if f$locate("@",command) .ne. f$length(command) then goto illegal_command
$ if f$locate("=",command) .ne. f$length(command) then goto illegal_command
$ if f$locate("F$",command) .ne. f$length(command) then goto illegal_command
$ verb = f$element(0," ",command)
 
$
$ if verb .EQS. "LOGOUT" then goto do_logout
$ if verb .EQS. "HELP" then goto do_help
$
$ write sys$output "%CAPTIVE-W-IVVERB, unrecognized command \",verb,"\"
$ goto next_command
$
$illegal_command:
$ write sys$output "%CAPTIVE-W-ILLEGAL, bad characters in command line"
$ goto next_command
$
$do_logout:
$ logout
$ goto next_command
$
$do_help:
$ define sys$input sys$command
$ help
$ goto next_command


Setting Priorities for User Processes  

A user's priority is the base priority used in scheduling the process that the system creates for the user.

On VAX systems, priorities range in value from a low of 0 to a high of 31; 0 through 15 are timesharing priorities; 16 through 31 are real-time priorities.

On Alpha and I64 systems, priorities range in value from a low of 0 to a high of 63; 0 through 15 are timesharing priorities; 16 through 63 are real-time priorities.

Processes with real-time priorities are scheduled strictly according to base priority; in other words, the executable real-time process with the highest base priority is executed first. Processes with timesharing priorities are scheduled according to a slightly different principle to promote overlapping of computation and I/O activities.

In the user's account record of the UAF, the default value of a user's priority is 4; for practical purposes, the minimum value is 0. Ensure that the priority for timesharing users remains at the default. Note that if you give some users an advantage over other users by raising their priorities, ragged performance results, because the system reacts sharply to even small base priority differences.


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