NAME
pwck - verify the integrity of password filesSYNOPSIS
pwck
[options] [
PASSWORDFILE [ SHADOWFILE ]]
DESCRIPTION
The pwck command verifies the integrity of the users and authentication information. It checks that all entries in /etc/passwd and /etc/shadow have the proper format and contain valid data. The user is prompted to delete entries that are improperly formatted or which have other uncorrectable errors. Checks are made to verify that each entry has:•the correct number of fields
•a unique and valid user name
•a valid user and group
identifier
•a valid primary group
•a valid home directory
•a valid login shell
Checks for shadowed password information are enabled when the second file
parameter SHADOWFILE is specified or when /etc/shadow exists on the
system.
These checks are the following:
•every passwd entry has a matching
shadow entry, and every shadow entry has a matching passwd entry
•passwords are specified in the
shadowed file
•shadow entries have the correct number
of fields
•shadow entries are unique in
shadow
•the last password changes are not in
the future
The checks for correct number of fields and unique user name are fatal. If the
entry has the wrong number of fields, the user will be prompted to delete the
entire line. If the user does not answer affirmatively, all further checks are
bypassed. An entry with a duplicated user name is prompted for deletion, but
the remaining checks will still be made. All other errors are warnings and the
user is encouraged to run the usermod command to correct the error.
The commands which operate on the /etc/passwd file are not able to alter
corrupted or duplicated entries. pwck should be used in those
circumstances to remove the offending entry.
OPTIONS
The -r and -s options cannot be combined. The options which apply to the pwck command are: --badnameAllow names that do not conform to
standards.
-h, --help
Display help message and exit.
-q, --quiet
Report errors only. The warnings which do not
require any action from the user won't be displayed.
-r, --read-only
Execute the pwck command in read-only
mode.
-R, --root CHROOT_DIR
Apply changes in the CHROOT_DIR
directory and use the configuration files from the CHROOT_DIR
directory. Only absolute paths are supported.
-s, --sort
Sort entries in /etc/passwd and /etc/shadow by
UID.
By default, pwck operates on the files /etc/passwd and /etc/shadow. The
user may select alternate files with the passwd and shadow
parameters.
CONFIGURATION
The following configuration variables in /etc/login.defs change the behavior of this tool: NONEXISTENT (string)If a system account intentionally does not
have a home directory that exists, this string can be provided in the
/etc/passwd entry for the account to indicate this. The result is that pwck
will not emit a spurious warning for this account.
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, 0 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.
FILES
/etc/groupGroup account information.
/etc/passwd
User account information.
/etc/shadow
Secure user account information.
EXIT VALUES
The pwck command exits with the following values: 0success
1
invalid command syntax
2
one or more bad password entries
3
can't open password files
4
can't lock password files
5
can't update password files
6
can't sort password files
SEE ALSO
group(5), grpck(8), passwd(5), shadow(5), usermod(8).03/23/2023 | shadow-utils 4.13 |