chpasswd

Sommaire

NOM

chpasswd - Mettre `a jour des mots de passe par lot

SYNOPSIS

chpasswd [options]

DESCRIPTION

The chpasswd command reads a list of user name and password pairs from standard input and uses this information to update a group of existing users. Each line is of the format:

nom_utilisateur:mot_de_passe

By default the supplied password must be in clear-text, and is encrypted by chpasswd. Also the password age will be updated, if present.

The default encryption algorithm can be defined for the system with the ENCRYPT_METHOD variable of /etc/login.defs, and can be overwiten with the -e, -m, or -c options.

chpasswd first update the password in memory, and then commit all the changes to disk if no errors occured for any users.

Cette commande est destin'ee aux gros syst`emes pour lesquels un nombre importants de comptes sont cr'e'es en une seule fois.

OPTIONS

Les options disponibles pour la commande chpasswd sont :

-c, --crypt-method

Use the specified method to encrypt the passwords.
The available methods are DES, MD5, NONE, and SHA256 or SHA512 if your libc support these methods.

-e, --encrypted

Indique que les mots de passe fournis sont chiffr'es.

-h, --help

Afficher un message d'aide et quitter.

-m, --md5

Permettre d'utiliser le chiffrement MD5, plut^ot que DES, lorsque les mots de passe fournis ne sont pas chiffr'es.

-s, --sha-rounds

Use the specified number of rounds to encrypt the passwords.
The value 0 means that the system will choose the default number of rounds for the crypt method (5000).
A minimal value of 1000 and a maximal value of 999,999,999 will be enforced.
You can only use this option with the SHA256 or SHA512 crypt method.
By default, the number of rounds is defined by the SHA_CRYPT_MIN_ROUNDS and SHA_CRYPT_MAX_ROUNDS variables in /etc/login.defs.

AVERTISSEMENTS

Pensez `a fixer les permissions ou umask afin d'emp^echer la lecture par les autres utilisateurs des fichiers non chiffr'es.

You should make sure the passwords and the encryption method respect the system's password policy.

CONFIGURATION

Les variables de configuration suivantes de /etc/login.defs modifient le comportement de cet outil :

ENCRYPT_METHOD (cha^ine ce caract`eres)

D'efinit les algorithmes de chiffrement par d'efaut du syst`eme pour coder les mots de passes (si aucun algorithme n'a 'et'e indiqu'e sur la ligne de commandes).
Il peut prendre une de ces valeurs :
* DES (par d'efaut)
* MD5
* SHA256
* SHA512

Remarque : ce param`etre remplace la variable MD5_CRYPT_ENAB.

MD5_CRYPT_ENAB (bool'een)

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.

SHA_CRYPT_MIN_ROUNDS (nombre), SHA_CRYPT_MAX_ROUNDS (nombre)

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.

FICHIERS

/etc/passwd

Informations sur les comptes des utilisateurs.

/etc/shadow

Informations s'ecuris'ees sur les comptes utilisateurs.

/etc/login.defs

Configuration de la suite des mots de passe cach'es Fo shadow password Fc.

VOIR AUSSI

passwd(1), newusers(8), login.defs(5), useradd(8).