Source Code 1992 March/Source_Code_CD-ROM_Walnut_Creek_March_1992.iso/usenet/altsrcs/2/2290/README

Text File | 1990-12-28 | 12.0 KB | 317 lines

This is the explanatory document for John F. Haugh II's login replacement.
This document is for version 2, last modified on 11/26/90.

This software is copyright 1988, 1989, 1990, John F. Haugh II.  All rights
reserved.  Use, duplication and disclosure is permitted according to the
guidelines listed below.

This software is being provided as a freely redistributable login clone.
You may distribute this software provided you do not charge for other than
transmission costs.  You are free to copy this software provided you
do not restrict the rights of the recipients to further copy this software.

THIS SOFTWARE IS BEING DISTRIBUTED AS-IS.  THE AUTHORS DISCLAIM ALL
LIABILITY FOR ANY CONSEQUENCES OF USE.  THE USER IS SOLELY RESPONSIBLE
FOR THE MAINTENANCE OF THIS SOFTWARE PACKAGE.  THE AUTHORS ARE UNDER NO
OBLIGATION TO PROVIDE MODIFICATIONS OR IMPROVEMENTS.  THE USER IS
ENCOURAGE TO TAKE ANY AND ALL STEPS NEEDED TO PROTECT AGAINST ACCIDENTAL
LOSE OF INFORMATION OR MACHINE RESOURCES.

Special thanks are due to Chip Rosenthal for his fine testing efforts;
to Steve Simmons for his work in porting this code to BSD; and to Bill
Kennedy for his contributions of LaserJet printer time and energies.

Begin by reading and editing the config.h file.  All options are selected
by using #define's.  A brief description for each available option appears
below.  You may want to print this file out as it is LONG and you will
need to refer to it while editting config.h.  You will also have to edit
the Makefile.  The possible differences are documented there.  Pay close
attention to the install: rule.  DO NOT MAIL ME DIFFERENCES FOR VARIOUS
INSTALLATION PROBLEMS.  If you must share your experiences, do so on the
net.  Login now runs on about 30 different varieties of UNIX that I have
been made aware of.

Note that there are MANY options.  As distributed most options are turned
on, which produces a really nice package.  This is the system as used on
the authors' machines.

Dialup Password Files -
    This option permits individual ports to have an additional
    password prompted for on a by-shell basis.  /etc/dialups
    contains a list of dialup ports, d_passwd contains the
    password for each shell requiring a dialup password.

    Select this option by defining the DIALUP macro.

Port Access Times File -
    This option permits individual ports to have restrictions
    based on user name and time of day and week.

    Select this option by defining the PORTTIME macro.

Shadow [ unreadable ] Password Files -
    This option utilizes an alternate, non-readable file to
    contain the actual encrypted passwords.  This is presumed
    to increase system security by increasing the difficulty
    with which system crackers obtain encrypted passwords.

    Select this option by defining the SHADOWPWD macro.

DBM Password Files -
    This option utilizes the DBM database access routines to
    increase the performance of user name and ID lookups in the
    password file.

    Select this option by defining both the DBM and GETPWENT
    macros.  The FGETPWENT macro must also be defined or the
    fgetpwent() library routine must be present.

Double Length Passwords -
    This option extends the maximum length of a user password
    to 16 characters from eight.

    Select this option by defining the DOUBLESIZE macro.
    Credit for this option is due Jonathan Bayer.

Obscure Password Testing -
    This option includes code to test user passwords for
    complexity.  The programmer is encouraged to edit the
    file obscure.c to add additional methods for detecting
    simplistic passwords.

    Select this option by defining the OBSCURE macro.

    Additionally, the PASSLENGTH macro must be defined to
    control the minimum length for a legal password.

Mandatory Password Prompting -
    This option requires all passwords, including null ones,
    to be prompted for.  Traditionally an account with a
    password field of '::' does not require prompting for.
    This option modifies this behavior to require even
    null passwords be prompted for.

    Select this option by defining the NOBLANK macro.

Password Aging Defaults -
    You may select the default number of days during which a
    password is valid.  The pwconv command adds aging
    information to accounts which do not include it already.

    The MINDAYS macro must be defined to be the minimum
    number of days which must pass before a password may be
    changed.  The MAXDAYS macro must be defined to be the
    maximum number of days which a password will remain
    valid during.

    The WARNDAYS macro controls how many days warning a user
    is given that their password is about to expire.  The
    default is 10.

HZ Environmental Variable -
    This option pre-defines the HZ environmental variable.
    Certain systems require this variable be defined for
    system time reporting functions to work properly.

    Select this option by defining the HZ macro to have
    the desired environmental variable value.

TZ Environmental Variable -
    This option pre-defines the TZ environmental variable.
    This provides a default timezone variable for use by
    various utilities.

    Select this option by defining the TZ macro to have
    the desired environmental variable value, or the name
    of the file containing the desired value.

Password Aging -
    This option includes code to perform password aging.
    Password aging is presumed to increase system security
    by forcing users to change passwords on a regular
    basis.  The resolution on password age is in weeks for
    non-shadow password systems and in days otherwise.

    Select this option by defining the AGING macro.

Mailbox Checking -
    This option includes code to check the status of the
    user's mailbox.  One of three messages are produced
    depending on the status of the user's mailbox.

    Select this option by defining the MAILCHECK macro.

Console Restricted Root Logins -
    This option restricts the port which root may legally
    login on.  This option presumably increases system
    security by preventing outside attacks against the root
    account.

    Select this option by defining the CONSOLE macro to
    have the desired port name.  If this file is a regular
    file, it is considered to contain a list of legal port
    names, one per line.  Note that the port names DO NOT
    begin with "/dev/" and that a file name would have to
    be fully qualified.  See config.h for a pair of
    examples.

Restricted User Logins -
    This option permits you to specify a file which disables
    user logins.  This options permits you to keep normal
    users off of the system while performing maintenance
    functions.

    Select this option by defining NOLOGINS to be the name
    of the file to use.

Restricted Use Accounts -
    This option permits certain accounts to be used for
    identification purposes only.  This options associates
    login ID's with UID's, such as for disk space accounting
    or anonymous FTP accounts.  Passwords for these accounts
    may only be changed by root.

    Select this option by defining NOUSE to be the string
    to include in the password file in place of the user's
    shell.

Message of the Day Printing -
    This option causes the message of the day to be
    printed at login time.

    Select this option by defining the MOTD macro.

    If you wish this feature to be overriden on a per-user
    basis, define the macro HUSHLOGIN and users may then
    turn off the /etc/motd message by creating a file
    '.hushlogin' in their home directories.

Last Login Time Logging -
    This option causes a record to be made of successful
    logins in /usr/adm/lastlog.  The format of the
    structure is defined in lastlog.h.

    Select this option by defining the LASTLOG macro.

    You will need to determine if you system already has
    a lastlog.h file and use that file if present.

Failed Login Logging -
    This option causes a record to be kept of the most
    recent login failure by date and port.  A cummulative
    count of failures is maintained and compared against
    an allowable limit.

    Select this option by defining the FAILLOG macro.

    An additional option is provided which will create
    utmp-like entries for each failed login.  Because of
    security concerns, only valid account names will be
    logged.

    Select this option by defining the FTMP macro to be
    the name of a utmp-like file.  You may control the
    recording of unknown login names by defining the
    UNKNOWNS macro.  This prevents possible passwords from
    being entered into the FTMP file.

    See the file faillog.h and config.h for more details.

Terminal Permissions -
    This option allows the terminal modes to be set at
    login time.  This is particularly useful to disable
    messages on user's terminals.

    Select this option by defining the TTYPERM macro as
    having the desired mode.

Terminal Type Setup -
    This option allows the terminal type to be set at
    login time.  The environmental variable TERM will be
    set from the specified terminal to port mapping
    file.

    Select this option by defining the TTYTYPE macro as
    having the value of the name of the type to port
    mapping file.  Credit for this option is due Chip
    Rosenthal.

File Size Setting -
    This option includes code to set the user's ulimit
    at login time.  Additional code to set the umask and
    nice value is also included.

    Select this option by defining the QUOTAS macro.

Switch-User Logging -
    This option causes su(1) to log attempts to switch
    users.  Su(1) will log all attempt, giving the old
    and new user ID's, tty port, and time.  It also
    indicates if the attempt was successful.

    Select this option by defining the SULOG macro to
    have the value of the name of the file you want
    attempts logged to.

Configurable Editing Keys -
    This options allows the erase and kill characters to
    be selected.  A default value is provided.  By default
    ERASE will be ^H and KILL will be ^U.

    Select this option by defining the ERASECHAR macro
    to be the desired erase character and the KILLCHAR
    macro to be the desired KILL character.

Default ulimit and umask Values -
    This option allows you to select the default values
    for ulimit and umask, allowing you to avoid
    regenerating your system kernel.  These values may be
    overriden with appropriate entries in the GECOS field.

    Select the default ulimit by defining the ULIMIT
    macro, and the default umask by defining the UMASK
    macro.

    Warning: These values will not apply to processes
    executed by /etc/cron or any of their children.

BSD Notes:    Steve Simmons    [e-mail]

The full port of the shadow package to BSD is not complete; but some
of the issues have been worked out.  These notes describe the current
state of things:

In order to make use of password aging under BSD, minor changes to
/usr/include/pwd.h and getpwent() are needed.  These changes are to
keep the password age from messing up the encrypted password when not
using shadow passwords, and involve placing a new field in the password
data structure.  To use this, you should apply the following two patches:
    pwd.h.patch
    getpwent.c.patch
to the BSD /usr/include/pwd.h and /usr/src/lib/libc/gen/getpwent.c,
respectively.  After applying the patches, rebuild your standard C
library with the new getpwent.  Programs which use the old getpwent
will fail on password checking if they do a strcmp rather than a strncmp.
[ I do not seem to have these two patches.  I have provided an entire
getpwent collection of code which may be useful instead. -jfh ]

These changes are based on BSD4.3, not Tahoe

ToDo BSD:

I'm working on this in my copious spare time (hah!); any help would
be appreciated.  If you decide to help, do these independantly rather
than rework BSD code!  Keep it redistributable!

No dbm functions have been put in place.  Dbm functionality is needed
for both /etc/password and /etc/shadow management.  [ It is now possible
to create /etc/passwd.dir and /etc/passwd.pag using the new mkpasswd
command.  getpwuid and getpwnam both use these files.   Also, the
commands chfn, chsh, and chage all update the DBM files. -jfh ]

The BSD GECOS field gets used for lots more stuff than the USG.  At a
minimum this functionality should be duplicated under BSD; better is to put
it into USG as well; still better would be to make the chfn command for
both systems; best would be site-configurable data to be put into GECOS/chfn.
[ this is now possible using chfn and the -o option. - jfh ]