Sudo (Español)

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Este artículo contiene una descripción de la conocida utilidad de dosificación de privilegios.
Descripción
Los grupos y usuarios son usados ​​en los sistemas GNU/Linux para el control de los accesos. El superusuario (root) tiene acceso completo al sistema operativo y a su configuración; su utilización está orientada para tareas de administración del sistema únicamente. Los usuarios sin privilegios pueden utilizar los programas su y sudo para controlar la realización de operaciones dosificando los privilegios.

sudo («substitute user do») permite que un administrador del sistema delegue autoridad para dar a ciertos usuarios (o grupos de usuarios) la capacidad de ejecutar algunas órdenes (o la totalidad) como root u otro usuario, al tiempo que permite auditar el rastro de las órdenes dadas y sus argumentos.[1]

Justificación

Sudo es una alternativa a su para ejecutar órdenes como root. A diferencia de su, el cual lanza una shell de root que permite además el acceso a todas las órdenes, sudo, por el contrario, realiza una dosificada entrega de privilegios temporales para una sola orden. El uso de sudo otorga los privilegios de root solo cuando es necesario y reduce el riesgo que un error tipográfico o un error en la invocación de una orden puede causar en el sistema. Sudo también se puede utilizar para ejecutar órdenes como otro u otros usuarios, y además, sudo registra todas las órdenes emitidas y los intentos fallidos.

Instalación

Instale el paquete sudo, disponible en los repositorios oficiales:

# pacman -S sudo

Para empezar a usar sudo por un usuario sin privilegios, debe estar correctamente configurado. Así que lea la sección de configuración.

Utilización

Con sudo, los usuarios normales pueden emitir órdenes con el prefijo sudo para ejecutárlas con privilegios de superusuario (o de otros grupos de usuarios).

Por ejemplo, para usar pacman:

$ sudo pacman -Syu

Véase el manual de sudo para obtener más información.

Configuración

Ver la configuración actual

Ejecute sudo -ll para visualizar la configuración actual de sudo.

Usar visudo

El archivo de configuración de sudo es /etc/sudoers. Sería conveniente que dicho archivo siempre se editase con la orden visudo. visudo bloquea el archivo sudoers, guarda las modificaciones en un archivo temporal y comprueba la gramática de ese archivo antes de copiarlo a /etc/sudoers.

Advertencia: ¡Es imperativo que el archivo sudoers no tenga errores de sintaxis! Cualquier error hará sudo inutilizable. Modifíquelo siempre con visudo para evitar errores.

El editor por defecto para visudo es vi. Será utilizado si no se especifica otro editor, configurado o bien con VISUAL o bien con EDITOR como variables de entorno (utilizado en ese orden) para el editor que desee, por ejemplo, vim. La orden se ejecuta como root:

# VISUAL="/usr/bin/vim -p -X" visudo

Se puede cambiar permanentemente la configuración de todo el sistema para, por ejemplo, vim, añadiendo:

export VISUAL="/usr/bin/vim -p -X"

en el archivo ~/.bashrc . Tenga en cuenta que este no entrará en vigor para las shells ya en ejecución.

Para usar permanentemente el editor elegido cuando se ejecuta la orden visudo, agregue la línea siguiente a /etc/sudoers (donde vim es el editor elegido):

# Resetea el entorno por defecto
Defaults      env_reset
# Establece el editor por defecto para vim, y no permite a visudo utilizar EDITOR/VISUAL.
Defaults      editor="/usr/bin/vim -p -X", !env_editor

Ejemplos de entradas

Para permitir a un usuario normal obtener privilegios de superusuario cuando antepone sudo a una orden, agregue la siguiente línea:

NOMBRE_DE_USUARIO   ALL=(ALL) ALL

Para permitir a un usuario ejecutar todas las órdenes de cualquier usuario, pero únicamente en el host NOMBRE_DEL_HOST de la máquina:

NOMBRE_DE_USUARIO   NOMBRE_DEL_HOST=(ALL) ALL

Para permitir que los miembros del grupo wheel tengan acceso sudo:

%wheel      ALL=(ALL) ALL

Para desactivar solicitar una contraseña para el usuario NOMBRE_DE_USUARIO:

Defaults:NOMBRE_DE_USUARIO      !authenticate

Para activar las órdenes definidas explícitamente solo para el usuario NOMBRE_DE_USUARIO en el host NOMBRE_DEL_HOST:

USER_NAME NOMBRE_DEL_HOST=/sbin/halt,/sbin/poweroff,/sbin/reboot,/usr/bin/pacman -Syu
Nota: La opción personalizada añadida debe ir al final del archivo, ya que las líneas posteriores anulan las anteriores. En particular, esta línea debe ser posterior a la línea %wheel si el usuario se encuentra en este grupo.

Para activar, sin necesidad de contraseña, las órdenes definidas explícitamente únicamente para el usuario NOMBRE_DE_USUARIO en el host NOMBRE_DEL_HOST:

NOMBRE_DE_USUARIO NOMBRE_DEL_HOST= NOPASSWD: /sbin/halt,/sbin/poweroff,/sbin/reboot,/usr/bin/pacman -Syu

Un ejemplo detallado de archivo sudoers se puede encontrar aquí. Por otro lado, véase el manual de sudoers para obtener más información.

Permisos de archivos predeterminados por sudoers

El propietario y el grupo para el archivo sudoers deben ser ambos 0. Los permisos de los archivos se deben establecer en 0440. Estos permisos se establecen de forma predeterminada, pero si accidentalmente los cambia, debe modificarlos de inmediato o sudo fallará.

# chown -c root:root /etc/sudoers
# chmod -c 0440 /etc/sudoers

Expiración de la contraseña

Los usuarios pueden estar interesados en cambiar el tiempo de espera predeterminado antes de que la contraseña almacenada en la caché caduque. Esto se logra con la opción timestamp_timeout en /etc/sudoers que se cuenta en minutos. Para configurar el tiempo de espera en 20 minutos:

Defaults:USER_NAME timestamp_timeout=20
Sugerencia: Para asegurar que sudo siempre pedirá una contraseña, establezca el tiempo de espera en 0. Para garantizar que la contraseña nunca expire, establezca timeout en menos de 0.

Consejos y trucos

Archivo de ejemplo

Este ejemplo es especialmente útil para aquellos que utilizan multiplexores de terminales como screen, tmux o ratpoison, y los que usan sudo desde scripts/cronjobs:

/etc/sudoers
Cmnd_Alias WHEELER = /usr/sbin/lsof, /bin/nice, /bin/ps, /usr/bin/top, /usr/local/bin/nano, /bin/netstat, /usr/bin/locate, /usr/bin/find, /usr/bin/rsync
Cmnd_Alias PROCESSES = /bin/nice, /bin/kill, /usr/bin/nice, /usr/bin/ionice, /usr/bin/top, /usr/bin/kill, /usr/bin/killall, /usr/bin/ps, /usr/bin/pkill
Cmnd_Alias EDITS = /usr/bin/vim, /usr/bin/nano, /usr/bin/cat, /usr/bin/vi
Cmnd_Alias ARCHLINUX = /usr/sbin/gparted, /usr/bin/pacman, /usr/bin/pacman-color

root ALL = (ALL) ALL
USER_NAME ALL = (ALL) ALL, NOPASSWD: WHEELER, NOPASSWD: PROCESSES, NOPASSWD: ARCHLINUX, NOPASSWD: EDITS
 
Defaults !requiretty, !tty_tickets, !umask
Defaults visiblepw, path_info, insults, lecture=always
Defaults loglinelen = 0, logfile =/var/log/sudo.log, log_year, log_host, syslog=auth
Defaults mailto=webmaster@foobar.com, mail_badpass, mail_no_user, mail_no_perms
Defaults passwd_tries = 8, passwd_timeout = 1
Defaults env_reset, always_set_home, set_home, set_logname
Defaults !env_editor, editor="/usr/bin/vim:/usr/bin/vi:/usr/bin/nano"
Defaults timestamp_timeout=360
Defaults passprompt="Sudo invoked by [%u] on [%H] - Cmd run as %U - Password for user %p:"

Activar la función autocompletar con Tab en Bash

Template:Keypress-completion, por defecto, no funciona cuando un usuario se añade inicialmente al archivo sudoers. Por ejemplo, Juan normalmente necesita escribir solo:

$ fire<Template:Keypress>

y la shell completará el mandato para él como:

$ firefox

Sin embargo, si Juan es agregado al archivo sudoers y escribe:

$ sudo fire<Template:Keypress>

la shell no hará nada.

Para activar Template:Keypress-completion con sudo, instale el paquete bash-completion desde los repositorios oficiales. Véase bash#Auto-completion para obtener más información

Como alternativa, añada lo siguiente al archivo ~/.bashrc:

complete -cf sudo

Ejecutar aplicaciones X11 utilizando sudo

Para permitir que sudo inicie una aplicación gráfica en X11, es necesario agregar:

Defaults env_keep += "HOME"

a visudo.

Desactivar sudo para cada terminal

Advertencia: Esto permitirá usar cualquier proceso desde la sesión de sudo.

Si le molesta que sudo, de forma predeterminada, le obligue a introducir la contraseña cada vez que se abre una nueva terminal, desactive tty_tickets:

Defaults !tty_tickets

Variables de entornos (¿Desactualizado?)

Si se tienen muchas variables de entorno, o exporta la configuración del proxy a través de export http_proxy="...", al usar sudo estas variables no se pasan a la cuenta de root, a menos que ejecute sudo con la opción -E.

$ sudo -E pacman -Syu

Debido a esto es posible que desee añadir un alias en ~/.bashrc:

alias sudo="sudo -E"

Otra manera de arreglar esto sería añadir en /etc/sudoers:

Defaults !env_reset

Si desea pasar únicamente las variables *_proxy, añada lo siguiente:

Defaults env_keep += "ftp_proxy http_proxy https_proxy no_proxy"

Añadir /sbin y /usr/sbin a la ruta de root

Si desea ejecutar órdenes de administración (aquellas que se ecuentran en /sbin o /usr/sbin) con sudo sin usar su ruta completa, agregue:

Defaults secure_path="/bin:/sbin:/usr/bin:/usr/sbin"

en /etc/sudoers.

Esto le permite hacer:

$ sudo comando

en lugar de:

$ sudo /sbin/comando

o:

$ sudo /usr/sbin/comando

Activar alias

Si utiliza muchos alias, habrá advertido que no se transfieren a la cuenta de root cuando usa sudo. No obstante, hay una manera fácil de hacer que funcionen. Solo tiene que añadir lo siguiente a ~/.bashrc o a /etc/bash.bashrc:

alias sudo='sudo '

Avisos

Los usuarios pueden configurar sudo para mostrar «avisos ingeniosos»» cuando se introduce una contraseña incorrecta, en lugar de mostrar el mensaje predeterminado «contraseña incorrecta» (wrong password) . Busque la línea Defaults en /etc/sudoers y añada el parámetro «insults», separándolo con una coma de las opciones existentes. El resultado final podría verse así:

#Defaults specification
Defaults insults

Para probar, escriba sudo -K para finalizar la sesión actual y dejar que sudo pida la contraseña de nuevo.

Contraseña root

Los usuarios pueden configurar sudo para pedir la contraseña de root, en lugar de la contraseña de usuario, añadiendo "rootpw" a la línea Defaults en /etc/sudoers:

Defaults timestamp_timeout=0,rootpw

Deshabilitar el acceso de root

Advertencia: Arch Linux no viene ajustado para funcionar con una cuenta de root desactivada. Los usuarios pueden encontrar problemas con este método.

Con sudo instalado y configurado, el usuario puede deshabilitar el inicio de sesión de root. Sin root, los «attackers», primero, deben adivinar un nombre de usuario configurado como un sudoer y, luego, la contraseña de usuario.

Advertencia: Asegúrese de que un usuario está correctamente configurado como un sudoer antes de desactivar la cuenta de root.

La cuenta puede ser bloqueada mediante passwd:

# passwd -l root

Una orden similar desbloquea root.

$ sudo passwd -u root

De forma alternativa, edite /etc/shadow y vuelva a colocar la contraseña cifrada de root con «!»:

root:!:12345::::::

Para activar el acceso de root de nuevo:

$ sudo passwd root

kdesu

kdesu puede ser utilizado bajo KDE para lanzar aplicaciones gráficas con privilegios de root. Es posible que, por defecto, kdesu trate de usar «su», incluso si la cuenta de root está desactivada. Afortunadamente se puede invocar kdesu para usar «sudo» en lugar de «su». Cree/modifique el archivo ~/.kde4/share/config/kdesurc:

[super-user-command]
super-user-command=sudo

PolicyKit

Al desactivar la cuenta de root, es necesario cambiar la configuración de PolicyKit para hacer que la autorización local actúe en consecuencia. El valor predeterminado es solicitar la contraseña de root, por lo que debe ser cambiado. Con polkit-1, esto se puede lograr mediante la edición de /etc/polkit-1/localauthority.conf.d/50-localauthority.conf de manera que AdminIdentities=unix-user:0 se modifique añadiéndole algo más, dependiendo de la configuración del sistema. Puede ser con una lista de usuarios y grupos, por ejemplo:

AdminIdentities=unix-group:wheel

o

AdminIdentities=unix-user:me;unixuser:mom;unix-group:wheel

Para obtener más información, véase man pklocalauthority.

NetworkManager

Incluso con la configuración anterior de PolicyKit todavía necesita configurar una política para NetworkManager. Esto está documentado en la página NetworkManager de esta wiki

Solución de problemas

Problemas de SSH con TTY

SSH no asigna una tty de forma predeterminada cuando se ejecuta un comando remoto. Sin una tty, sudo no puede desactivar «echo» cuando pida la contraseña. Puede utilizar la opción -tt para obligar a SSH a asignar una tty (utilice -tt dos veces).

La opción requiretty de Defaults solo permite al usuario ejecutar sudo si tiene una tty.

# Desactive "ssh hostname sudo <cmd>", ya que mostrará la contraseña en texto claro. Se tiene que ejecutar "ssh -t hostname sudo <cmd>".
#
#Defaults    requiretty

Mostrar privilegios del usuario

Se puede averiguar cuáles son los privilegios que un usuario en particular tiene con la siguiente orden:

$ sudo -lU sunombredeusuario

O vea su cuenta con:

$ sudo -l
Matching Defaults entries for yourusename on this host:
(''«Juego de entradas Defaults para sunombredeusuario en este host:»'')
    loglinelen=0, logfile=/var/log/sudo.log, log_year, syslog=auth, mailto=sqpt.webmaster@gmail.com, mail_badpass, mail_no_user, mail_no_perms, env_reset, always_set_home, tty_tickets, lecture=always, pwfeedback, rootpw, set_home

User yourusename may run the following commands on this host:
(''«El usuario sunombredeusuario puede ejecutar las siguientes órdenes en este host:»'')

    (ALL) ALL
    (ALL) NOPASSWD: /usr/sbin/lsof, /bin/nice, /bin/netstat, /usr/bin/su, /usr/bin/locate, /usr/bin/find, /usr/bin/rsync, /usr/bin/strace,
    (ALL) /bin/nice, /bin/kill, /usr/bin/nice, /usr/bin/ionice, /usr/bin/top, /usr/bin/kill, /usr/bin/killall, /usr/bin/ps, /usr/bin/pkill
    (ALL) /usr/sbin/gparted, /usr/bin/pacman
    (ALL) /usr/local/bin/synergyc, /usr/local/bin/synergys
    (ALL) /usr/bin/vim, /usr/bin/nano, /usr/bin/cat
    (root) NOPASSWD: /usr/local/bin/synergyc

Umask permisiva

Sudo reunifica el valor umask del usuario con el del propio umask (que por defecto es 0022). Esto evita que sudo cree archivos con permisos más abiertos que el umask del usuario permite. Si bien esto es un valor predefinido aceptable si el umask personalizado no está en uso, esto puede llevar a situaciones en las que un programa dirigido por sudo puede crear archivos con permisos diferentes que si los ejecutara root directamente. Si se incurre en este tipo de errores, sudo proporciona un medio para fijar la umask del usuario, incluso en el caso de que la umask sea más permisiva respecto de la umask especificada por el usuario. La adición de las líneas de abajo (usando visudo) modificará tal comportamiento por defecto de sudo:

Defaults umask = 0022
Defaults umask_override

Esto establece la umask de sudo para la umask por defecto de root (0022) y sobrescribe el comportamiento predefinido, utilizando siempre la umask indicada, independientemente de cómo la umask del usuario esté configurada.

Skeleton predefinidos

En este enlace se puede encontrar una lista de todas las opciones disponibles para su uso con la orden Defaults en /etc/sudoers.

Tango-edit-clear.pngThis article or section needs language, wiki syntax or style improvements.Tango-edit-clear.png

Reason: the comments in the following block of code are truncated. (Discuss in Talk:Sudo (Español)#)

Esa misma lista se reproduce justo debajo en un formato optimizado para copiar y pegar en los archivos sudoers y luego hacer los cambios.

#Defaults       always_set_home
# always_set_home: If enabled, sudo will set the HOME environment variable to the home directory of the target user (which is root unless the -u option is used).  This effectively means that the -H op
#     always_set_home is only effective for configurations where either env_reset is disabled or HOME is present in the env_keep list.  This flag is off by default.

#Defaults       authenticate
# authenticate: If set, users must authenticate themselves via a password (or other means of authentication) before they may run commands.  This default may be overridden via the PASSWD and NOPASSWD t

#Defaults       closefrom_override
# closefrom_override: If set, the user may use sudo's -C option which overrides the default starting point at which sudo begins closing open file descriptors.  This flag is off by default.

#Defaults       compress_io
# compress_io: If set, and sudo is configured to log a command's input or output, the I/O logs will be compressed using zlib.  This flag is on by default when sudo is compiled with zlib support.

#Defaults       env_editor
# env_editor: If set, visudo will use the value of the EDITOR or VISUAL environment variables before falling back on the default editor list.  Note that this may create a security hole as it allows th
#   separated list of editors in the editor variable.  visudo will then only use the EDITOR or VISUAL if they match a value specified in editor.  This flag is on by default.

#Defaults       env_reset
# env_reset: If set, sudo will run the command in a minimal environment containing the TERM, PATH, HOME, MAIL, SHELL, LOGNAME, USER, USERNAME and SUDO_* variables.  Any variables in the caller's envir
#   in the file specified by the env_file option (if any).  The default contents of the env_keep and env_check lists are displayed when sudo is run by root with the -V option.  If the secure_path opti
#   default.

#Defaults       fast_glob
# fast_glob: Normally, sudo uses the glob(3) function to do shell-style globbing when matching path names.  However, since it accesses the file system, glob(3) can take a long time to complete for som
#   (automounted).  The fast_glob option causes sudo to use the fnmatch(3) function, which does not access the file system to do its matching.  The disadvantage of fast_glob is that it is unable to ma
#   names that include globbing characters are used with the negation operator, '!', as such rules can be trivially bypassed.  As such, this option should not be used when sudoers contains rules that

#Defaults       fqdn
# fqdn: Set this flag if you want to put fully qualified host names in the sudoers file.  I.e., instead of myhost you would use myhost.mydomain.edu.  You may still use the short form if you wish (and
#   sudo unusable if DNS stops working (for example if the machine is not plugged into the network).  Also note that you must use the host's official name as DNS knows it.  That is, you may not use a
#     all aliases from DNS.  If your machine's host name (as returned by the hostname command) is already fully qualified you shouldn't need to set fqdn.  This flag is off by default.

#Defaults       ignore_dot
# ignore_dot: If set, sudo will ignore '.' or '' (current dir) in the PATH environment variable; the PATH itself is not modified.  This flag is off by default.

#Defaults       ignore_local_sudoers
# ignore_local_sudoers: If set via LDAP, parsing of /etc/sudoers will be skipped.  This is intended for Enterprises that wish to prevent the usage of local sudoers files so that only LDAP is used.  Th
#   present, /etc/sudoers does not even need to exist. Since this option tells sudo how to behave when no specific LDAP entries have been matched, this sudoOption is only meaningful for the cn=default

#Defaults       insults
# insults: If set, sudo will insult users when they enter an incorrect password.  This flag is off by default.

#Defaults       log_host
# log_host: If set, the host name will be logged in the (non-syslog) sudo log file.  This flag is off by default.

#Defaults       log_input
# log_input: If set, sudo will run the command in a pseudo tty and log all user input.  If the standard input is not connected to the user's tty, due to I/O redirection or because the command is part
#   Input is logged to the directory specified by the iolog_dir option (/var/log/sudo-io by default) using a unique session ID that is included in the normal sudo log line, prefixed with TSID=.  The i
#   Note that user input may contain sensitive information such as passwords (even if they are not echoed to the screen), which will be stored in the log file unencrypted.  In most cases, logging the

#Defaults       log_output
# log_output: If set, sudo will run the command in a pseudo tty and log all output that is sent to the screen, similar to the script(1) command.  If the standard output or standard error is not connec
#   is also captured and stored in separate log files.
#   Output is logged to the directory specified by the iolog_dir option (/var/log/sudo-io by default) using a unique session ID that is included in the normal sudo log line, prefixed with TSID=.  The
#   Output logs may be viewed with the sudoreplay(8) utility, which can also be used to list or search the available logs.

#Defaults       log_year
# log_year: If set, the four-digit year will be logged in the (non-syslog) sudo log file.  This flag is off by default.

#Defaults       long_otp_prompt
# long_otp_prompt: When validating with a One Time Password (OTP) scheme such as S/Key or OPIE, a two-line prompt is used to make it easier to cut and paste the challenge to a local window.  It's not

#Defaults       mail_always
# mail_always: Send mail to the mailto user every time a users runs sudo.  This flag is off by default.

#Defaults       mail_badpass
# mail_badpass: Send mail to the mailto user if the user running sudo does not enter the correct password.  This flag is off by default.

#Defaults       mail_no_host
# mail_no_host: If set, mail will be sent to the mailto user if the invoking user exists in the sudoers file, but is not allowed to run commands on the current host.  This flag is off by default.

#Defaults       mail_no_perms
# mail_no_perms: If set, mail will be sent to the mailto user if the invoking user is allowed to use sudo but the command they are trying is not listed in their sudoers file entry or is explicitly den

#Defaults       mail_no_user
# mail_no_user: If set, mail will be sent to the mailto user if the invoking user is not in the sudoers file.  This flag is on by default.

#Defaults       noexec
# noexec: If set, all commands run via sudo will behave as if the NOEXEC tag has been set, unless overridden by a EXEC tag.  See the description of NOEXEC and EXEC below as well as the "PREVENTING SHE

#Defaults       path_info
# path_info: Normally, sudo will tell the user when a command could not be found in their PATH environment variable.  Some sites may wish to disable this as it could be used to gather information on t
#   the executable is simply not in the user's PATH, sudo will tell the user that they are not allowed to run it, which can be confusing.  This flag is on by default.

#Defaults       passprompt_override
# passprompt_override: The password prompt specified by passprompt will normally only be used if the password prompt provided by systems such as PAM matches the string "Password:".  If passprompt_over

#Defaults       preserve_groups
# preserve_groups: By default, sudo will initialize the group vector to the list of groups the target user is in.  When preserve_groups is set, the user's existing group vector is left unaltered.  The
#   default.

#Defaults       pwfeedback
# pwfeedback: By default, sudo reads the password like most other Unix programs, by turning off echo until the user hits the return (or enter) key.  Some users become confused by this as it appears to
#   the user presses a key.  Note that this does have a security impact as an onlooker may be able to determine the length of the password being entered.  This flag is off by default.

#Defaults       requiretty
# requiretty: If set, sudo will only run when the user is logged in to a real tty.  When this flag is set, sudo can only be run from a login session and not via other means such as cron(8) or cgi-bin

#Defaults       root_sudo
# root_sudo: If set, root is allowed to run sudo too.  Disabling this prevents users from "chaining" sudo commands to get a root shell by doing something like "sudo sudo /bin/sh".  Note, however, that
#   real additional security; it exists purely for historical reasons.  This flag is on by default.

#Defaults       rootpw
# rootpw: If set, sudo will prompt for the root password instead of the password of the invoking user.  This flag is off by default.

#Defaults       runaspw
# runaspw: If set, sudo will prompt for the password of the user defined by the runas_default option (defaults to root) instead of the password of the invoking user.  This flag is off by default.

#Defaults       set_home
# set_home: If enabled and sudo is invoked with the -s option the HOME environment variable will be set to the home directory of the target user (which is root unless the -u option is used).  This eff
#   is enabled, so set_home is only effective for configurations where either env_reset is disabled or HOME is present in the env_keep list.  This flag is off by default.

#Defaults       set_logname
# set_logname: Normally, sudo will set the LOGNAME, USER and USERNAME environment variables to the name of the target user (usually root unless the -u option is given).  However, since some programs (
#   may be desirable to change this behavior.  This can be done by negating the set_logname option.  Note that if the env_reset option has not been disabled, entries in the env_keep list will override

#Defaults       set_utmp
# set_utmp: When enabled, sudo will create an entry in the utmp (or utmpx) file when a pseudo-tty is allocated.  A pseudo-tty is allocated by sudo when the log_input, log_output or use_pty flags are e
#   the tty, time, type and pid fields updated.  This flag is on by default.

#Defaults       setenv
# setenv: Allow the user to disable the env_reset option from the command line via the -E option.  Additionally, environment variables set via the command line are not subject to the restrictions impo
#   variables in this manner.  This flag is off by default.

#Defaults       shell_noargs
# shell_noargs: If set and sudo is invoked with no arguments it acts as if the -s option had been given.  That is, it runs a shell as root (the shell is determined by the SHELL environment variable if
#   is off by default.

#Defaults       stay_setuid
# stay_setuid: Normally, when sudo executes a command the real and effective UIDs are set to the target user (root by default).  This option changes that behavior such that the real UID is left as the
#   systems that disable some potentially dangerous functionality when a program is run setuid.  This option is only effective on systems with either the setreuid() or setresuid() function.  This flag

#Defaults       targetpw
# targetpw: If set, sudo will prompt for the password of the user specified by the -u option (defaults to root) instead of the password of the invoking user.  In addition, the timestamp file name will
#   passwd database as an argument to the -u option.  This flag is off by default.

#Defaults       tty_tickets
# tty_tickets: If set, users must authenticate on a per-tty basis.  With this flag enabled, sudo will use a file named for the tty the user is logged in on in the user's time stamp directory.  If disa

#Defaults       umask_override
# umask_override: If set, sudo will set the umask as specified by sudoers without modification.  This makes it possible to specify a more permissive umask in sudoers than the user's own umask and matc
#   user's umask and what is specified in sudoers.  This flag is off by default.

#Defaults       use_pty
# use_pty: If set, sudo will run the command in a pseudo-pty even if no I/O logging is being gone.  A malicious program run under sudo could conceivably fork a background process that retains to the u
#   that impossible.  This flag is off by default.

#Defaults       utmp_runas
# utmp_runas: If set, sudo will store the name of the runas user when updating the utmp (or utmpx) file.  By default, sudo stores the name of the invoking user.  This flag is off by default.

#Defaults       visiblepw
# visiblepw: By default, sudo will refuse to run if the user must enter a password but it is not possible to disable echo on the terminal.  If the visiblepw flag is set, sudo will prompt for a passwor
#   somehost sudo ls" since rsh(1) does not allocate a tty.  This flag is off by default.

#Defaults       closefrom
# closefrom: Before it executes a command, sudo will close all open file descriptors other than standard input, standard output and standard error (ie: file descriptors 0-2).  The closefrom option can

#Defaults       passwd_tries
# passwd_tries: The number of tries a user gets to enter his/her password before sudo logs the failure and exits.  The default is 3.

#Defaults       loglinelen
# loglinelen: Number of characters per line for the file log.  This value is used to decide when to wrap lines for nicer log files.  This has no effect on the syslog log file, only the file log.  The

#Defaults       passwd_timeout
# passwd_timeout: Number of minutes before the sudo password prompt times out, or 0 for no timeout.  The timeout may include a fractional component if minute granularity is insufficient, for example 2

#Defaults       timestamp_timeout
# timestamp_timeout: Number of minutes that can elapse before sudo will ask for a passwd again.  The timeout may include a fractional component if minute granularity is insufficient, for example 2.5.
#   timestamp will never expire.  This can be used to allow users to create or delete their own timestamps via sudo -v and sudo -k respectively.

#Defaults       umask
# umask: Umask to use when running the command.  Negate this option or set it to 0777 to preserve the user's umask.  The actual umask that is used will be the union of the user's umask and the value o
#   running a command.  Note on systems that use PAM, the default PAM configuration may specify its own umask which will override the value set in sudoers.

#Defaults       badpass_message
# badpass_message: Message that is displayed if a user enters an incorrect password.  The default is Sorry, try again. unless insults are enabled.

#Defaults       editor
# editor: A colon (':') separated list of editors allowed to be used with visudo.  visudo will choose the editor that matches the user's EDITOR environment variable if possible, or the first editor in

#Defaults       iolog_dir
# iolog_dir: The top-level directory to use when constructing the path name for the input/output log directory.  Only used if the log_input or log_output options are enabled or when the LOG_INPUT or L
#   directory.  The default is "/var/log/sudo-io".
#   The following percent (`%') escape sequences are supported:
#     %{seq} - expanded to a monotonically increasing base-36 sequence number, such as 0100A5, where every two digits are used to form a new directory, e.g. 01/00/A5
#     %{user} - expanded to the invoking user's login name
#     %{group} - expanded to the name of the invoking user's real group ID
#     %{runas_user} - expanded to the login name of the user the command will be run as (e.g. root)
#     %{runas_group} - expanded to the group name of the user the command will be run as (e.g. wheel)
#     %{hostname} - expanded to the local host name without the domain name
#     %{command} - expanded to the base name of the command being run
#   In addition, any escape sequences supported by the system's strftime() function will be expanded.
#   To include a literal `%' character, the string `%%' should be used.

#Defaults       iolog_file
# iolog_file: The path name, relative to iolog_dir, in which to store input/output logs when the log_input or log_output options are enabled or when the LOG_INPUT or LOG_OUTPUT tags are present for a
#   See the iolog_dir option above for a list of supported percent (`%') escape sequences.
#   In addition to the escape sequences, path names that end in six or more Xs will have the Xs replaced with a unique combination of digits and letters, similar to the mktemp() function.

#Defaults       mailsub
# mailsub: Subject of the mail sent to the mailto user. The escape %h will expand to the host name of the machine.  Default is *** SECURITY information for %h ***.

#Defaults       noexec_file
# noexec_file: This option is no longer supported.  The path to the noexec file should now be set in the /etc/sudo.conf file.

#Defaults       passprompt
# passprompt: The default prompt to use when asking for a password; can be overridden via the -p option or the SUDO_PROMPT environment variable.  The following percent (`%') escape sequences are suppo
#     %H  expanded to the local host name including the domain name (only if the machine's host name is fully qualified or the fqdn option is set)
#     %h  expanded to the local host name without the domain name
#     %p  expanded to the user whose password is being asked for (respects the rootpw, targetpw and runaspw flags in sudoers)
#     %U  expanded to the login name of the user the command will be run as (defaults to root)
#     %u  expanded to the invoking user's login name
#     %%  two consecutive % characters are collapsed into a single % character
#   The default value is Password:.

#Defaults       runas_default
# runas_default: The default user to run commands as if the -u option is not specified on the command line.  This defaults to root.

#Defaults       syslog_badpri
# syslog_badpri: Syslog priority to use when user authenticates unsuccessfully.  Defaults to alert.
#   The following syslog priorities are supported: alert, crit, debug, emerg, err, info, notice, and warning.

#Defaults       syslog_goodpri
# syslog_goodpri: Syslog priority to use when user authenticates successfully.  Defaults to notice.
#   See syslog_badpri for the list of supported syslog priorities.

#Defaults       sudoers_locale
# sudoers_locale: Locale to use when parsing the sudoers file, logging commands, and sending email.  Note that changing the locale may affect how sudoers is interpreted.  Defaults to "C".

#Defaults       timestampdir
# timestampdir: The directory in which sudo stores its timestamp files.  The default is /var/db/sudo.

#Defaults       timestampowner
# timestampowner: The owner of the timestamp directory and the timestamps stored therein.  The default is root.

#Defaults       env_file
# env_file: The env_file option specifies the fully qualified path to a file containing variables to be set in the environment of the program being run.  Entries in this file should either be of the f
#   quotes.  Variables in this file are subject to other sudo environment settings such as env_keep and env_check.

#Defaults       exempt_group
# exempt_group: Users in this group are exempt from password and PATH requirements.  The group name specified should not include a % prefix.  This is not set by default.

#Defaults       group_plugin
# group_plugin: A string containing a sudoers group plugin with optional arguments.  This can be used to implement support for the nonunix_group syntax described earlier.  The string should consist of
#   configuration arguments the plugin requires.  These arguments (if any) will be passed to the plugin's initialization function.  If arguments are present, the string must be enclosed in double quot
#   For example, given /etc/sudo-group, a group file in Unix group format, the sample group plugin can be used:
#   Defaults group_plugin="sample_group.so /etc/sudo-group"
#   For more information see sudo_plugin(5).

#Defaults       lecture
# lecture: This option controls when a short lecture will be printed along with the password prompt.  It has the following possible values:
#     always  Always lecture the user.
#     never   Never lecture the user.
#     once    Only lecture the user the first time they run sudo.
#   If no value is specified, a value of once is implied.  Negating the option results in a value of never being used.  The default value is once.

#Defaults       lecture_file
# lecture_file: Path to a file containing an alternate sudo lecture that will be used in place of the standard lecture if the named file exists.  By default, sudo uses a built-in lecture.

#Defaults       listpw
# listpw: This option controls when a password will be required when a user runs sudo with the -l option.  It has the following possible values:
#     all     All the user's sudoers entries for the current host must have the NOPASSWD flag set to avoid entering a password.
#     always  The user must always enter a password to use the -l option.
#     any     At least one of the user's sudoers entries for the current host must have the NOPASSWD flag set to avoid entering a password.
#     never   The user need never enter a password to use the -l option.
#   If no value is specified, a value of any is implied.  Negating the option results in a value of never being used.  The default value is any.

#Defaults       logfile
# logfile: Path to the sudo log file (not the syslog log file).  Setting a path turns on logging to a file; negating this option turns it off.  By default, sudo logs via syslog.

#Defaults       mailerflags
# mailerflags: Flags to use when invoking mailer. Defaults to -t.

#Defaults       mailerpath
# mailerpath: Path to mail program used to send warning mail.  Defaults to the path to sendmail found at configure time.

#Defaults       mailfrom
# mailfrom: Address to use for the "from" address when sending warning and error mail.  The address should be enclosed in double quotes (") to protect against sudo interpreting the @ sign.  Defaults t

#Defaults       mailto
# mailto: Address to send warning and error mail to.  The address should be enclosed in double quotes (") to protect against sudo interpreting the @ sign.  Defaults to root.

#Defaults       secure_path
# secure_path: Path used for every command run from sudo.  If you don't trust the people running sudo to have a sane PATH environment variable you may want to use this.  Another use is if you want to
#   option are not affected by secure_path.  This option is not set by default.

#Defaults       syslog
# syslog: Syslog facility if syslog is being used for logging (negate to disable syslog logging).  Defaults to auth.
#   The following syslog facilities are supported: authpriv (if your OS supports it), auth, daemon, user, local0, local1, local2, local3, local4, local5, local6, and local7.

#Defaults       verifypw
# verifypw: This option controls when a password will be required when a user runs sudo with the -v option.  It has the following possible values:
#     all     All the user's sudoers entries for the current host must have the NOPASSWD flag set to avoid entering a password.
#     always  The user must always enter a password to use the -v option.
#     any     At least one of the user's sudoers entries for the current host must have the NOPASSWD flag set to avoid entering a password.
#     never   The user need never enter a password to use the -v option.
#   If no value is specified, a value of all is implied.  Negating the option results in a value of never being used.  The default value is all.

#Defaults       env_check
# env_check: Environment variables to be removed from the user's environment if the variable's value contains % or / characters.  This can be used to guard against printf-style format vulnerabilities
#   value without double-quotes.  The list can be replaced, added to, deleted from, or disabled by using the =, +=, -=, and ! operators respectively.  Regardless of whether the env_reset option is ena
#   they pass the aforementioned check.  The default list of environment variables to check is displayed when sudo is run by root with the -V option.

#Defaults       env_delete
# env_delete: Environment variables to be removed from the user's environment when the env_reset option is not in effect.  The argument may be a double-quoted, space-separated list or a single value w
#   +=, -=, and ! operators respectively.  The default list of environment variables to remove is displayed when sudo is run by root with the -V option.  Note that many operating systems will remove p

#Defaults       env_keep
# env_keep: Environment variables to be preserved in the user's environment when the env_reset option is in effect.  This allows fine-grained control over the environment sudo-spawned processes will r
#   quotes.  The list can be replaced, added to, deleted from, or disabled by using the =, +=, -=, and ! operators respectively.  The default list of variables to keep is displayed when sudo is run by