prpasswd(4) Kernel Interfaces Manual 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, acces-
sible 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. User profile information was formerly main-
tained 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, how-
ever, 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 tem-
plate 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 associ-
ated functions are as follows: This is the user name for the account. The string must match the name of the file and a user name in a cor-
responding /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. This is the user ID for the account. The number must match the user ID field of the correspond-
ing /etc/passwd entry. This field is ignored if it is set in a template or in the default database. 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 data-
base. This is a priority number used by authentication programs to modify the nice value of a login process for the user (see the setpri-
ority(2) reference page). This field is the numeric value corresponding to SET_PROC_ACNTL. This number is used in conjunction with the
u_auditmask mask. 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. 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. 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. 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. The number in this field speci-
fies 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. 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. 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. 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. 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. 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. 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. This field controls the ability of a user to gener-
ate 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. This field con-
trols 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. This field controls the ability of the user to choose a null password for the account. A u_nullpw en-
try indicates a null password can be chosen; a u_nullpw@ entry indicates that it cannot. 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. This field controls the ability of the user to generate random characters for a password. A u_genchars entry indi-
cates that the user can generate passwords made up of random characters; a u_genchars@ entry indicates that he cannot. 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. This field is a number (0 to 9) representing the number of old
encrypted passwords to keep to prevent reuse of previously used passwords. 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. This field is the algorithm number used to encrypt the current password. This field is ignored if it is set in a tem-
plate or in the default database. This field is the algorithm number used to encrypt future passwords. 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. 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. This field is a character string that identi-
fies 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. 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 tem-
plate or in the default database. 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. 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.
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. 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. 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. This field is a number indicating the time in
seconds to wait before re-enabling the account after an unsuccessful login attempt (u_unsuclog). 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. 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. The actual time of type time_t that an account is set to expire. 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. 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. The RLIMIT_CPU rlim_max numeric value set by the setrlimit() system call at
login time. The RLIMIT_FSIZE rlim_max numeric value set by the setrlimit() system call at login time. The RLIMIT_DATA rlim_max numeric
value set by the setrlimit() system call at login time. The RLIMIT_STACK rlim_max numeric value set by the setrlimit() system call at
login time. The RLIMIT_CORE rlim_max numeric value set by the setrlimit() system call at login time. The RLIMIT_RSS rlim_max numeric
value set by the setrlimit() system call at login time. The RLIMIT_NOFILE rlim_max numeric value set by the setrlimit() system call at
login time. The RLIMIT_VMEM rlim_max numeric value set by the setrlimit() system call at login time. 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. This filed is a numeric value of type time_t. In a user pro-
file, 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. 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. 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.
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 confor-
mance, 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 other-
wise 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 unsuc-
cessful password change times as well as the last successful and unsuccessful login times and terminal names.
FILES
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. 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. 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) delim off delim off
prpasswd(4)