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prpasswd(4)
NAME
prpasswd, prpwd - Protected password authentication database (Enhanced
Security)
DESCRIPTION
An authentication profile is maintained for each user on the system. This
user profile is kept in the protected password database, accessible only to
trusted programs acting on behalf of the trusted computing base (TCB). The
protected password database contains among other things the encrypted
password for the user account, which must be hidden from untrusted users.
Note
User profile information was formerly maintained in separate
files. Such files are no longer supported. If found during an
update installation, the convuser program automatically converts
the files into database format.
The protected password database does not eliminate the need for the
/etc/passwd and the /etc/group files. Users must be defined in the passwd
file in order to use the system. The protected password database entry for
a user contains the user name and user ID to provide a correlation to the
user's /etc/passwd entry. There must be a match or the user account is
treated as invalid. (Template accounts, however, are defined only in the
protected password database.)
User profiles reside in /tcb/files/auth.db, for accounts such as root that
must be accessible in single-user mode, and in //var/tcb/files/auth.db, for
the majority of accounts. Each user's authentication profile contains
values that are interpreted by trusted programs acting as part of the TCB.
These fields define user-specific values, and are used before template
account or system default template values for the same field are used.
Values are obtained as follows:
· If the user profile contains a user-specific value, that value is
used.
· If the user profile contains a reference to a template account, and no
user-specific value is defined, the value in the template account is
used.
· If neither the user profile nor the template account defines a value
for a field and the system default template defines a value for that
field, the system default template value is used.
· If the value is defined nowhere else, a static system default is used
for the field.
The system default template values are located in /etc/auth/system/default,
and can be modified through the dxaccount utility using the View Local
Template option, or through the edauth utility.
The protected password database contains keyword field identifiers and
depending on the field type, a value for that field (certain field types do
not require an explicit value). The exact syntax for field specifications
is consistent for all authentication databases and is described in the
authcap(4) reference page. The keyword field identifiers supported by the
protected password database and their associated functions are as follows:
u_name This is the user name for the account. The string must match the
name of the file and a user name in a corresponding /etc/passwd
entry. The maximum length for Tru64 UNIX user names is currently
8 characters. This field is ignored if it is set in a template
or in the default database.
u_id This is the user ID for the account. The number must match the
user ID field of the corresponding /etc/passwd entry. This field
is ignored if it is set in a template or in the default database.
u_pwd This field contains the encrypted password string for the account
if the account has a password. This field is ignored if it is
set in a template or in the default database.
u_priority
This is a priority number used by authentication programs to
modify the nice value of a login process for the user (see the
setpriority(2) reference page).
u_auditcntl
This field is the numeric value corresponding to SET_PROC_ACNTL.
This number is used in conjunction with the u_auditmask mask.
u_auditmask
This field consists of a comma-separated list of audit event
names. The events are the same as those specified in the
auditmask(8) reference page. An entry of u_auditmask=all
specifies all system calls and trusted events.
u_minchg This field specifies the minimum password change time in seconds.
If the number is nonzero, the password cannot be changed until
the specified number of seconds since the last successful
password change have passed unless the person changing the
password is authorized to override this constraint.
u_minlen The number in this field specifies the minimum length of the user
account password. If the field is zero, a dynamic value is
calculated as defined in the Green Book.
u_maxlen The number in this field specifies the maximum length of the user
account password for generated passwords only. It should be less
than the system-wide maximum value defined by the <prot.h>
constant AUTH_MAX_PASSWD_LENGTH.
u_minchosen
The number in this field specifies the minimum length of the user
account password for user-chosen passwords only. If the field is
zero, a dynamic value is calculated as defined in the Green Book.
u_maxchosen
The number in this field specifies the maximum length of the user
account password for user-chosen passwords only. To encourage
longer, more secure user passwords, set it to allow the system-
wide maximum value defined by the <prot.h> constant
AUTH_MAX_PASSWD_LENGTH.
u_exp The number in this field is a time_t value that specifies how
long from a successful change until the account password expires.
When a password expires, system authentication programs request
that the password be changed when the user logs in to the system.
If the password lifetime expires before the password is changed,
the account is disabled.
u_life The number in this field is a time_t value that specifies the
lifetime of a password. If this time interval is reached, the
account is disabled and can only be unlocked by an authorized
system administrator.
u_succhg The time in this field is a time_t value that indicates the time
of the last successful password change. This field should only
be set by programs that can be used to change the account
password. This field is ignored if it is set in a template or in
the default database.
u_unsucchg
The time in this field is a time_t value that indicates the time
of the last unsuccessful password change. This field should only
be set by programs that can be used to change the account
password. This field is ignored if it is set in a template or in
the default database.
u_pickpw This field controls the ability of the user to pick a password
for the account. A u_pickpw entry indicates that the user can
pick his own password; a u_pickpw@ entry indicates that he
cannot. This permits an account to be configured so that a user
cannot pick a password but instead has a password generated by
the system.
u_genpwd This field controls the ability of a user to generate a password
for the account. A u_genpwd entry indicates that the system will
generate the password for the user; a u_genpwd@ entry indicates
that the user can pick his own password. The system is capable
of generating passwords containing random words.
u_restrict
This field controls whether password triviality checks are
performed on any user-selected passwords. A u_restrict entry
indicates that triviality checks are performed; a u_restrict@
entry indicates they are not performed. Triviality checks
include verifying that the password is not a login or group name,
a palindrome, or a word recognized by the spell program. See the
acceptable_password(3) reference page for more information on
triviality checks for passwords.
u_nullpw This field controls the ability of the user to choose a null
password for the account. A u_nullpw entry indicates a null
password can be chosen; a u_nullpw@ entry indicates that it
cannot.
u_pwchanger
This field is a string representing the user name of the last
person to change the account password if that user was not the
account's owner. This is used to warn the user at login time if
the account password has been changed, possibly without the
knowledge of the user. This field is ignored if it is set in a
template or in the default database.
u_genchars
This field controls the ability of the user to generate random
characters for a password. A u_genchars entry indicates that the
user can generate passwords made up of random characters; a
u_genchars@ entry indicates that he cannot.
u_genletters
This field controls the ability of the user to generate random
letters for a password. A u_genletters entry indicates that the
user can generate passwords made up of random letters; a
u_genletters@ entry indicates that he cannot.
u_pwdepth This field is a number (0 to 9) representing the number of old
encrypted passwords to keep to prevent reuse of previously used
passwords.
u_pwdict This field is a comma-separated list strings representing the old
encrypted passwords. The length of the list is determined by
u_pwdepth. This field is ignored if it is set in a template or
in the default database.
u_oldcrypt
This field is the algorithm number used to encrypt the current
password. This field is ignored if it is set in a template or in
the default database.
u_newcrypt
This field is the algorithm number used to encrypt future
passwords.
u_suclog The time in this field is a time_t value that contains the system
time of the last successful login to the account. The system-
wide default d_skip_success_login_log controls whether or not
this field is updated at each login. This field is ignored if it
is set in a template or in the default database.
u_unsuclog
The time in this field is a time_t value that contains the system
time of the last unsuccessful login attempt to the account.
Updates to this field control breakin detection and evasion. The
system-wide default d_skip_fail_login_log controls whether or not
this field is updated at each login failure. This field is
ignored if it is set in a template or in the default database.
u_suctty This field is a character string that identifies the name of the
terminal associated with the last successful login to the
account. The systemwide default d_skip_ttys_update controls
whether or not this field is updated at each login. This field
is ignored if it is set in a template or in the default database.
u_numunsuclog
This field contains a number indicating the number of
unsuccessful login attempts to the account and is reset when a
successful login to the account occurs. If a login is attempted
during the time period from u_unsuclog to u_unsuclog plus
u_unlock, andu_numunsuclog is not less than u_maxtries, the login
is refused. (This check is suppressed if the u_maxtries field is
set to zero.) The system-wide default d_skip_fail_login_log
controls whether or not this field is updated at each login
failure. This field is ignored if it is set in a template or in
the default database.
u_unsuctty
This field is a character string that identifies the name of the
terminal associated with the last unsuccessful login attempt to
the account. This field is ignored if it is set in a template or
in the default database.
u_tod This field is a string that contains a comma-separated list of
time-of-day specification entries that control when the user
account can be used for login.
u_maxtries
The number in this field specifies the maximum number of
consecutive unsuccessful login attempts to the account that are
permitted until the account is disabled. Setting this field to 0
prevents the account from being disabled because of retry
failures. In this case, u_numunsuclog is incremented, but not
checked.
u_retired This field indicates whether the account is retired or not. An
account that has been retired cannot be used for any purpose. A
u_retired entry indicates that the account is retired; a
u_retired@ entry indicates that it is not. This field is ignored
if it is set in a template or in the default database.
u_lock This field is used to administratively lock an account. A u_lock
entry indicates that the account is locked; a u_lock@ entry
indicates that it is not. A user cannot log in to a locked
account. An account can also be disabled by other means. See
getprpwent(3) for more information.
u_unlock This field is a number indicating the time in seconds to wait
before re-enabling the account after an unsuccessful login
attempt (u_unsuclog).
u_flogins This field is the displayable count of the number of unsuccessful
login attempts. The system-wide default d_skip_fail_login_log
controls whether or not this field is updated at each login
failure. This field is ignored if it is set in a template or in
the default database.
u_policy This field is used to control whether the /tcb/bin/pwpolicy file
is consulted for validating password changes. A u_policy entry
indicates that the /tcb/bin/pwpolicy file is consulted; a
u_policy@ entry indicates that it is not.
u_expdate The actual time of type time_t that an account is set to expire.
u_vacation_start
This field is a numeric value of type time_t that indicates the
start of user's scheduled vacation. This field is ignored if it
is set in a template or in the default database.
u_vacation_end
This field is a numeric value of type time_t that indicates the
end of user's scheduled vacation. This field is ignored if it is
set in a template or in the default database.
u_rlimit_cpu
The RLIMIT_CPU rlim_max numeric value set by the setrlimit()
system call at login time.
u_rlimit_fsize
The RLIMIT_FSIZE rlim_max numeric value set by the setrlimit()
system call at login time.
u_rlimit_data
The RLIMIT_DATA rlim_max numeric value set by the setrlimit()
system call at login time.
u_rlimit_stack
The RLIMIT_STACK rlim_max numeric value set by the setrlimit()
system call at login time.
u_rlimit_core
The RLIMIT_CORE rlim_max numeric value set by the setrlimit()
system call at login time.
u_rlimit_rss
The RLIMIT_RSS rlim_max numeric value set by the setrlimit()
system call at login time.
u_rlimit_nofile
The RLIMIT_NOFILE rlim_max numeric value set by the setrlimit()
system call at login time.
u_rlimit_vmem
The RLIMIT_VMEM rlim_max numeric value set by the setrlimit()
system call at login time.
u_max_login_intvl
A numeric value representing the maximum time, in seconds, since
last successful login before account is disabled. If set for an
account (or system-wide), the user is automatically considered
"locked out" if the last successful login was more than the
specified interval before the current time. As with other
is_locked_out() checks, the grace-period feature allows an
override.
u_grace_limit
This filed is a numeric value of type time_t. In a user profile,
it is the timestamp until which automatic lockouts are bypassed
(so locked_out_es() says no). In the system defaults database,
it is the interval to be added to the current time when clicking
on Unlock Account in the dxaccounts GUI.
This field allows a time-limited bypass to the is_locked_out()
checks so an administrator can allow a user to log in until a
specified time of day (for example, until 5pm). This bypasses
anything except the u_lock administration lock on an account.
This field is ignored if it is set in a template or in the
default database.
u_psw_change_reqd
A boolean expression indicating that the administrator requires a
password change now. Unlike zeroing the u_suclog field, this
still obeys the password lifetime requirements before refusing
further logins. Note: While the old method of zeroing fd_schange
still works, this method conforms to the Green Book. This field
is ignored if it is set in a template or in the default database.
u_template
This field is the name of the template which provides default
values for those fields for which no user-specific value is
defined. This field is ignored if it is set in a template or in
the default database.
u_istemplate
This field indicates that the account is a template only. This
field is ignored if it is set in a template or in the default
database.
The u_vacation_* fields allow the user to specify a start and end date/time
for vacation. This causes the login/password controls to ignore that
period of time for things like password lifetime and "you must log in every
so often". In order to retain Green Book conformance, it also disallows
logins during that timespan.
The setrlimit() system call controls or restricts system resources some (or
all) users. These resources include how much CPU time they can have, how
much virtual address space they can have (how much swap space), how many
file descriptors they can have open, and each of the other things (total of
8) controlled through setrlimit(). This sets hard limits, and restricts
soft limits to match if they would otherwise be over the new hard limits.
The getprpwent routines are used to parse the protected password database
files into a prpasswd structure that can be used by programs. A flag in
the structure indicates whether a particular field in the structure and
hence the field is defined. System default values are also provided in the
structure. These values are derived from the /etc/auth/system/default file
and can be used by programs in the absence of a user-specific value.
EXAMPLES
The following example shows a typical protected password database entry:
perry:u_name=perry:u_id#101:\
:u_pwd=aZXtu1kmSpEzm:\
:u_minchg#0:u_succhg#653793862:u_unsucchg#622581606:u_nullpw:\
:u_suclog#671996425:u_suctty=tty1:\
:u_unsuclog#660768767:u_unsuctty=tty1:\
:u_maxtries#3:chkent:
This protected password database entry is for the user perry. The user ID
for perry is 101. This value must match the /etc/passwd entry for this
user. The account has a password and its encrypted form is specified by
the u_pwd field.
The database entry specifies a minimum password change time of 0,
indicating that the password can be changed at any time. Furthermore, the
account is permitted to have a null password. The account has a maximum
consecutive unsuccessful login threshold of 3, indicating that the account
is locked after three failed attempts. The remaining fields provide
account information such as the last successful and unsuccessful password
change times as well as the last successful and unsuccessful login times
and terminal names.
FILES
/tcb/files/auth.db
Specifies the pathname of the protected password database for
accounts with UIDs less than AUTH_MIN_GEN_UID, which is set to
100 by default.
/var/tcb/files/auth.db
The pathname of the protected password database for accounts with
UIDs greater than or equal to AUTH_MIN_GEN_UID, which is set to
100 by default.
/etc/auth/system/default
The system default database that defines system-wide global
parameters.
RELATED INFORMATION
Commands: login(1), passwd(1), auditmask(8), authck(8)
System Calls: setrlimit(2)
Functions: locked_out_es(3), nice(3), acceptable_password(3),
getprpwent(3), time_lock(3)
Files: authcap(4), default(4), group(4), passwd(4)
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Alphabetical
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