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NAMN
login.defs - shadow password suite configuration
BESKRIVNING
The /etc/login.defs file defines the site-specific configuration for
the shadow password suite. This file is required. Absence of this file
will not prevent system operation, but will probably result in
undesirable operation.
This file is a readable text file, each line of the file describing one
configuration parameter. The lines consist of a configuration name and
value, separated by whitespace. Blank lines and comment lines are
ignored. Comments are introduced with a "#" pound sign and the pound
sign must be the first non-white character of the line.
Parameter values may be of four types: strings, booleans, numbers, and
long numbers. A string is comprised of any printable characters. A
boolean should be either the value yes or no. An undefined boolean
parameter or one with a value other than these will be given a no
value. Numbers (both regular and long) may be either decimal values,
octal values (precede the value with 0) or hexadecimal values (precede
the value with 0x). The maximum value of the regular and long numeric
parameters is machine-dependent.
Följande konfigurationsposter tillhandahålls:
CHFN_RESTRICT (string)
This parameter specifies which values in the gecos field of the
/etc/passwd file may be changed by regular users using the chfn
program. It can be any combination of letters f, r, w, h, for Full
name, Room number, Work phone, and Home phone, respectively. For
backward compatibility, yes is equivalent to rwh and no is
equivalent to frwh. If not specified, only the superuser can make
any changes. The most restrictive setting is better achieved by not
installing chfn SUID.
CONSOLE_GROUPS (string)
List of groups to add to the user´s supplementary group set when
logging in on the console (as determined by the CONSOLE setting).
Default is none.
Use with caution - it is possible for users to gain permanent
access to these groups, even when not logged in on the console.
DEFAULT_HOME (boolean)
Indicate if login is allowed if we can´t cd to the home directory.
Default in no.
If set to yes, the user will login in the root (/) directory if it
is not possible to cd to her home directory.
ENCRYPT_METHOD (string)
This defines the system default encryption algorithm for encrypting
passwords (if no algorithm are specified on the command line).
It can take one of these values:
· DES (default)
· MD5
· SHA256
· SHA512
Note: this parameter overrides the MD5_CRYPT_ENAB variable.
Note: if you use PAM, it is recommended to set this variable
consistently with the PAM modules configuration.
ENV_HZ (string)
If set, it will be used to define the HZ environment variable when
a user login. The value must be preceded by HZ=. A common value on
Linux is HZ=100.
The HZ environment variable is only set when the user (the
superuser) logs in with sulogin.
ENV_PATH (string)
If set, it will be used to define the PATH environment variable
when a regular user login. The value can be preceded by PATH=, or a
colon separated list of paths (for example /bin:/usr/bin). The
default value is PATH=/bin:/usr/bin.
ENV_SUPATH (string)
If set, it will be used to define the PATH environment variable
when the superuser login. The value can be preceded by PATH=, or a
colon separated list of paths (for example
/sbin:/bin:/usr/sbin:/usr/bin). The default value is
PATH=/bin:/usr/bin.
ERASECHAR (number)
Terminal ERASE character (010 = backspace, 0177 = DEL).
The value can be prefixed "0" for an octal value, or "0x" for an
hexadecimal value.
FAIL_DELAY (number)
Delay in seconds before being allowed another attempt after a login
failure.
FAKE_SHELL (string)
If set, login will execute this shell instead of the users´ shell
specified in /etc/passwd.
GID_MAX (number), GID_MIN (number)
Range of group IDs used for the creation of regular groups by
useradd, useradd, or newusers.
HUSHLOGIN_FILE (string)
If defined, this file can inhibit all the usual chatter during the
login sequence. If a full pathname is specified, then hushed mode
will be enabled if the user´s name or shell are found in the file.
If not a full pathname, then hushed mode will be enabled if the
file exists in the user´s home directory.
KILLCHAR (number)
Terminal KILL character (025 = CTRL/U).
The value can be prefixed "0" for an octal value, or "0x" for an
hexadecimal value.
LOG_OK_LOGINS (boolean)
Enable logging of successful logins.
LOG_UNKFAIL_ENAB (boolean)
Enable display of unknown usernames when login failures are
recorded.
Note: logging unknown usernames may be a security issue if an user
enter her password instead of her login name.
LOGIN_RETRIES (number)
Maximum number of login retries in case of bad password.
This will most likely be overriden by PAM, since the default
pam_unix module has it´s own built in of 3 retries. However, this
is a safe fallback in case you are using an authentication module
that does not enforce PAM_MAXTRIES.
LOGIN_TIMEOUT (number)
Max time in seconds for login.
MAIL_DIR (string)
The mail spool directory. This is needed to manipulate the mailbox
when its corresponding user account is modified or deleted. If not
specified, a compile-time default is used.
MAIL_FILE (string)
Defines the location of the users mail spool files relatively to
their home directory.
The MAIL_DIR and MAIL_FILE variables are used by useradd, usermod, and
userdel to create, move, or delete the user´s mail spool.
MAX_MEMBERS_PER_GROUP (number)
Maximum members per group entry. When the maximum is reached, a new
group entry (line) is started in /etc/group (with the same name,
same password, and same GID).
The default value is 0, meaning that there are no limits in the
number of members in a group.
This feature (split group) permits to limit the length of lines in
the group file. This is useful to make sure that lines for NIS
groups are not larger than 1024 characters.
If you need to enforce such limit, you can use 25.
Note: split groups may not be supported by all tools (even in the
Shadow toolsuite. You should not use this variable unless you
really need it.
MD5_CRYPT_ENAB (boolean)
Indicate if passwords must be encrypted using the MD5-based
algorithm. If set to yes, new passwords will be encrypted using the
MD5-based algorithm compatible with the one used by recent releases
of FreeBSD. It supports passwords of unlimited length and longer
salt strings. Set to no if you need to copy encrypted passwords to
other systems which don´t understand the new algorithm. Default is
no.
This variable is superceded by the ENCRYPT_METHOD variable or by
any command line option used to configure the encryption algorithm.
This variable is deprecated. You should use ENCRYPT_METHOD.
Note: if you use PAM, it is recommended to set this variable
consistently with the PAM modules configuration.
PASS_MAX_DAYS (number)
The maximum number of days a password may be used. If the password
is older than this, a password change will be forced. If not
specified, -1 will be assumed (which disables the restriction).
PASS_MIN_DAYS (number)
The minimum number of days allowed between password changes. Any
password changes attempted sooner than this will be rejected. If
not specified, -1 will be assumed (which disables the restriction).
PASS_WARN_AGE (number)
The number of days warning given before a password expires. A zero
means warning is given only upon the day of expiration, a negative
value means no warning is given. If not specified, no warning will
be provided.
PASS_MAX_DAYS, PASS_MIN_DAYS and PASS_WARN_AGE are only used at the
time of account creation. Any changes to these settings won´t affect
existing accounts.
SHA_CRYPT_MIN_ROUNDS (number), SHA_CRYPT_MAX_ROUNDS (number)
When ENCRYPT_METHOD is set to SHA256 or SHA512, this defines the
number of SHA rounds used by the encryption algorithm by default
(when the number of rounds is not specified on the command line).
With a lot of rounds, it is more difficult to brute forcing the
password. But note also that more CPU resources will be needed to
authenticate users.
If not specified, the libc will choose the default number of rounds
(5000).
The values must be inside the 1000-999999999 range.
If only one of the SHA_CRYPT_MIN_ROUNDS or SHA_CRYPT_MAX_ROUNDS
values is set, then this value will be used.
If SHA_CRYPT_MIN_ROUNDS > SHA_CRYPT_MAX_ROUNDS, the highest value
will be used.
SULOG_FILE (string)
If defined, all su activity is logged to this file.
SU_NAME (string)
If defined, the command name to display when running "su -". For
example, if this is defined as "su" then a "ps" will display the
command is "-su". If not defined, then "ps" would display the name
of the shell actually being run, e.g. something like "-sh".
SYS_GID_MAX (number), SYS_GID_MIN (number)
Range of group IDs used for the creation of system groups by
useradd, groupadd, or newusers.
SYS_UID_MAX (number), SYS_UID_MIN (number)
Range of user IDs used for the creation of system users by useradd
or newusers.
SYSLOG_SG_ENAB (boolean)
Enable "syslog" logging of sg activity.
SYSLOG_SU_ENAB (boolean)
Enable "syslog" logging of su activity - in addition to sulog file
logging.
TTYGROUP (string), TTYPERM (string)
The terminal permissions: the login tty will be owned by the
TTYGROUP group, and the permissions will be set to TTYPERM.
By default, the ownership of the terminal is set to the user´s
primary group and the permissions are set to 0600.
TTYGROUP can be either the name of a group or a numeric group
identifier.
If you have a write program which is "setgid" to a special group
which owns the terminals, define TTYGROUP to the group number and
TTYPERM to 0620. Otherwise leave TTYGROUP commented out and assign
TTYPERM to either 622 or 600.
TTYTYPE_FILE (string)
If defined, file which maps tty line to TERM environment parameter.
Each line of the file is in a format something like "vt100 tty01".
UID_MAX (number), UID_MIN (number)
Range of user IDs used for the creation of regular users by useradd
or newusers.
UMASK (number)
The permission mask is initialized to this value. If not specified,
the permission mask will be initialized to 022.
USERDEL_CMD (string)
If defined, this command is run when removing a user. It should
remove any at/cron/print jobs etc. owned by the user to be removed
(passed as the first argument).
USERGROUPS_ENAB (boolean)
CROSS REFERENCES
The following cross references show which programs in the shadow
password suite use which parameters.
chfn
CHFN_RESTRICT
chgpasswd
ENCRYPT_METHOD MAX_MEMBERS_PER_GROUP MD5_CRYPT_ENAB
SHA_CRYPT_MAX_ROUNDS SHA_CRYPT_MIN_ROUNDS
chpasswd
ENCRYPT_METHOD MD5_CRYPT_ENAB SHA_CRYPT_MAX_ROUNDS
SHA_CRYPT_MIN_ROUNDS
gpasswd
ENCRYPT_METHOD MAX_MEMBERS_PER_GROUP MD5_CRYPT_ENAB
SHA_CRYPT_MAX_ROUNDS SHA_CRYPT_MIN_ROUNDS
groupadd
GID_MAX GID_MIN MAX_MEMBERS_PER_GROUP SYS_GID_MAX SYS_GID_MIN
groupdel
MAX_MEMBERS_PER_GROUP
groupmems
MAX_MEMBERS_PER_GROUP
groupmod
MAX_MEMBERS_PER_GROUP
grpck
MAX_MEMBERS_PER_GROUP
grpconv
MAX_MEMBERS_PER_GROUP
grpunconv
MAX_MEMBERS_PER_GROUP
login
CONSOLE_GROUPS DEFAULT_HOME ERASECHAR FAIL_DELAY FAKE_SHELL
HUSHLOGIN_FILE KILLCHAR LOGIN_RETRIES LOGIN_TIMEOUT LOG_OK_LOGINS
LOG_UNKFAIL_ENAB TTYGROUP TTYPERM TTYTYPE_FILE USERGROUPS_ENAB
newgrp
SYSLOG_SG_ENAB
newusers
ENCRYPT_METHOD GID_MAX GID_MIN MAX_MEMBERS_PER_GROUP MD5_CRYPT_ENAB
PASS_MAX_DAYS PASS_MIN_DAYS PASS_WARN_AGE SHA_CRYPT_MAX_ROUNDS
SHA_CRYPT_MIN_ROUNDS SYS_GID_MAX SYS_GID_MIN SYS_UID_MAX
SYS_UID_MIN UID_MAX UID_MIN UMASK
pwck
PASS_MAX_DAYS PASS_MIN_DAYS PASS_WARN_AGE
pwconv
PASS_MAX_DAYS PASS_MIN_DAYS PASS_WARN_AGE
su
CONSOLE_GROUPS DEFAULT_HOME ENV_PATH ENV_SUPATH SULOG_FILE SU_NAME
SYSLOG_SU_ENAB
sulogin
ENV_HZ
useradd
GID_MAX GID_MIN MAIL_DIR MAX_MEMBERS_PER_GROUP PASS_MAX_DAYS
PASS_MIN_DAYS PASS_WARN_AGE SYS_GID_MAX SYS_GID_MIN SYS_UID_MAX
SYS_UID_MIN UID_MAX UID_MIN UMASK
userdel
MAIL_DIR MAIL_FILE MAX_MEMBERS_PER_GROUP USERDEL_CMD
USERGROUPS_ENAB
usermod
MAIL_DIR MAIL_FILE MAX_MEMBERS_PER_GROUP
vipw
MAX_MEMBERS_PER_GROUP
FEL
Much of the functionality that used to be provided by the shadow
password suite is now handled by PAM. Thus, /etc/login.defs is no
longer used by programs such as: login(1), passwd(1), su(1). Please
refer to the corresponding PAM configuration files instead.
SE OCKSÅ
login(1), passwd(1), su(1), passwd(5), shadow(5), pam(8).