chpasswd(8)

НАЗВА
chpasswd - оновлення паролів у пакетному режимі

КОРОТКИЙ ОГЛЯД

chpasswd [options]

ОПИС

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:

user_name:password

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

By default, passwords are encrypted by PAM, but (even if not recommended) you can select a different encryption method with the -e, -m, or -c options.

Except when PAM is used to encrypt the passwords, chpasswd first updates all the passwords in memory, and then commits all the changes to disk if no errors occurred for any user.

When PAM is used to encrypt the passwords (and update the passwords in the system database) then if a password cannot be updated chpasswd continues updating the passwords of the next users, and will return an error code on exit.

Цю команду призначено для використання у великих системних середовищах, де одночасно створюють багато облікових записів.

ПАРАМЕТРИ

The options which apply to the chpasswd command are:

-c, --crypt-method METHOD
    Скористатися для шифрування паролів вказаним методом.

    The available methods are BCRYPT, DES, MD5, SHA256, SHA512, YESCRYPT and NONE if your libc supports these methods.

    Типово, для шифрування паролів буде використано PAM.

-e, --encrypted
    Надані паролі подано у зашифрованій формі.

-h, --help
    Показати довідкове повідомлення і завершити роботу.

-m, --md5
    Скористатися шифруванням MD5 замість DES, якщо надані паролі не зашифровано.

-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. No SELINUX support.

-P, --prefix PREFIX_DIR
    Apply changes to configuration files under the root filesystem found under the directory PREFIX_DIR. This option does not chroot and is intended for preparing a cross-compilation target. Some limitations: NIS and LDAP users/groups are not verified. PAM authentication is using the host files. No SELINUX support.

-s, --sha-rounds ROUNDS
    Використати вказану кількість циклів шифрування паролів.

    You can only use this option with crypt method: BCRYPT SHA256 SHA512 YESCRYPT

    By default, the number of rounds for BCRYPT is defined by the BCRYPT_MIN_ROUNDS and BCRYPT_MAX_ROUNDS variables in /etc/login.defs.

    A minimal value of 4 and a maximal value of 31 will be enforced for BCRYPT. The default number of rounds is 13.

    By default, the number of rounds for SHA256 or SHA512 is defined by the SHA_CRYPT_MIN_ROUNDS and SHA_CRYPT_MAX_ROUNDS variables in /etc/login.defs.

    A minimal value of 1000 and a maximal value of 999,999,999 will be enforced for SHA256 and SHA512. The default number of rounds is 5000.

    By default, the number of rounds for YESCRYPT is defined by the YESCRYPT_COST_FACTOR in /etc/login.defs.

    A minimal value of 1 and a maximal value of 11 will be enforced for YESCRYPT. The default number of rounds is 5.

ЗАСТЕРЕЖЕННЯ

Не забудьте встановити права доступу або umask, щоб запобігти доступності до читання нешифрованих файлів сторонніми користувачами.

НАЛАШТУВАННЯ

The following configuration variables in /etc/login.defs change the behavior of this tool:

BCRYPT_MIN_ROUNDS (number), BCRYPT_MAX_ROUNDS (number)
    When ENCRYPT_METHOD is set to BCRYPT, this defines the number of BCRYPT 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 force the password. But note also that more CPU resources will be needed to authenticate users.

    The values must be inside the 4-31 range.

    If only one of the BCRYPT_MIN_ROUNDS or BCRYPT_MAX_ROUNDS values is set, then this value will be used.

    If BCRYPT_MIN_ROUNDS > BCRYPT_MAX_ROUNDS, the highest value will be used.

    Note: this only affect the generation of group passwords. The generation of user passwords is done by PAM and subject to the PAM configuration. It is recommended to set this variable consistently with the PAM configuration.

SHA_CRYPT_MIN_ROUNDS (number), SHA_CRYPT_MAX_ROUNDS (number)
    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 force 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), which is orders of magnitude too low for modern hardware.

    The values must be inside the 1000-999,999,999 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.

    Note: this only affect the generation of group passwords. The generation of user passwords is done by PAM and subject to the PAM configuration. It is recommended to set this variable consistently with the PAM configuration.

YESCRYPT_COST_FACTOR (number)
    When ENCRYPT_METHOD is set to YESCRYPT, this defines the cost factor used by the encryption algorithm by default (when the cost factor is not specified on the command line).

    With a high cost factor, it is more difficult to brute force the password. But note also that more CPU resources will be needed to authenticate users.

    The value must be inside the 1-11 range.

    Note: this only affect the generation of group passwords. The generation of user passwords is done by PAM and subject to the PAM configuration. It is recommended to set this variable consistently with the PAM configuration.

ФАЙЛИ

/etc/passwd
    Відомості щодо облікових записів користувача.

/etc/shadow
    Відомості щодо захищених облікових записів користувачів.

/etc/login.defs
    Налаштування комплексу для роботи з прихованими паролями.

/etc/pam.d/chpasswd
    PAM configuration for chpasswd.

ДИВ. ТАКОЖ

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