SHADOW(5)

NOM
shadow - fichier des mots de passe cachés

DESCRIPTION

shadow is a file which contains the password information for the system's accounts and optional aging information.

Ce fichier ne doit pas être accessible en lecture par les utilisateurs normaux afin de maintenir la sécurité des mots de passe, en particuliers pour prévenir les attaques par dictionnaires.

Each line of this file contains 9 fields, separated by colons (« : »), in the following order:

login name
    It must be a valid account name, which exists on the system.

encrypted password
    If the password field is empty, the user can log in without a password. However, some applications that read the /etc/shadow file might block access if the password field is empty.

    If the password field begins with an exclamation mark !, the password is locked. The remaining characters on the line represent the password hash.

    If the password hash consists of a star *, password access is effectively disallowed; this is because no password can produce a hash like this.

    Refer to crypt(3) for details on how this string is interpreted.

    If the password field contains a string that is not a valid result of crypt(3), for instance ! or *, the user cannot use a UNIX password to log in. However, the user may log in the system by other means.

date of last password change
    The date of the last password change, expressed as the number of days since 1970-01-01 00:00:00 UTC.

    The value 0 indicates that the user must change their password the next time they log in to the system.

    Un champ vide indique que les fonctionnalités de vieillissement de mot de passe sont désactivées.

minimum password age
    This deprecated field should be empty, and is ignored.

maximum password age
    The maximum password age is the number of days after which the user must change their password.

    After this number of days has elapsed, the password may still be valid. The user is prompted to change their password at the next login.

    Un champ vide signifie qu'il n'y a pour le mot de passe aucune limite d'âge, aucune période d'avertissement d'expiration et aucune période d'inactivité (voir ci-dessous).

    Si l'âge maximum du mot de passe est plus petit que l'âge minimum du mot de passe, l'utilisateur ne pourra pas changer son mot de passe.

password warning period
    The number of days before a password expires (see the maximum password age above) during which the user is warned.

    An empty field and value 0 mean that there is no password warning period.

password inactivity period
    The number of days after a password expires (see the maximum password age above) during which the password is still accepted, and the user must update their password at the next login.

    After the password expires and the password inactivity period elapses, the user cannot log in and must contact their administrator.

    An empty string means that no inactivity period is enforced.

account expiration date
    The date when the account expires, expressed as the number of days since 1970-01-01.

    Note that account expiration differs from password expiration. Account expiration prevents the user from logging in, whereas password expiration only prevents users from logging in with their password.

    An empty field means that the account never expires.

    The value 0 should not be used, as it is interpreted either as an account with no expiration or as an expiration date of 1970-01-01.

reserved field
    Ce champ est réservé pour une utilisation future.

FICHIERS

/etc/passwd
    Informations sur les comptes des utilisateurs.

/etc/shadow
    Informations sécurisées sur les comptes utilisateurs.

/etc/shadow-
    Fichier de sauvegarde pour /etc/shadow.

    Notez que ce fichier est utilisé par les outils de la suite d'outils shadow, mais pas par tous les outils de gestion d'utilisateurs et de mot de passes.

VOIR AUSSI

chage(1), login(1), passwd(1), passwd(5), pwck(8), pwconv(8), pwunconv(8), su(1), sulogin(8).