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sudo(8)                     System Manager's Manual                    sudo(8)


NAME

     sudo, sudoedit - execute a command as another user


SYNOPSIS

     sudo -h | -K | -k | -V
     sudo -v [-ABkNnS] [-g group] [-h host] [-p prompt] [-u user]
     sudo -l [-ABkNnS] [-g group] [-h host] [-p prompt] [-U user] [-u user]
          [command [arg ...]]
     sudo [-ABbEHnPS] [-C num] [-D directory] [-g group] [-h host] [-p prompt]
          [-R directory] [-T timeout] [-u user] [VAR=value] [-i | -s]
          [command [arg ...]]
     sudoedit [-ABkNnS] [-C num] [-D directory] [-g group] [-h host]
              [-p prompt] [-R directory] [-T timeout] [-u user] file ...


DESCRIPTION

     sudo allows a permitted user to execute a command as the superuser or
     another user, as specified by the security policy.  The invoking user's
     real (not effective) user-ID is used to determine the user name with
     which to query the security policy.

     sudo supports a plugin architecture for security policies, auditing, and
     input/output logging.  Third parties can develop and distribute their own
     plugins to work seamlessly with the sudo front-end.  The default security
     policy is sudoers, which is configured via the file
     /opt/local/etc/sudoers, or via LDAP.  See the Plugins section for more
     information.

     The security policy determines what privileges, if any, a user has to run
     sudo.  The policy may require that users authenticate themselves with a
     password or another authentication mechanism.  If authentication is
     required, sudo will exit if the user's password is not entered within a
     configurable time limit.  This limit is policy-specific; the default
     password prompt timeout for the sudoers security policy is 0 minutes.

     Security policies may support credential caching to allow the user to run
     sudo again for a period of time without requiring authentication.  By
     default, the sudoers policy caches credentials on a per-terminal basis
     for 5 minutes.  See the timestamp_type and timestamp_timeout options in
     sudoers(5) for more information.  By running sudo with the -v option, a
     user can update the cached credentials without running a command.

     On systems where sudo is the primary method of gaining superuser
     privileges, it is imperative to avoid syntax errors in the security
     policy configuration files.  For the default security policy, sudoers(5),
     changes to the configuration files should be made using the sudo(8)
     utility which will ensure that no syntax errors are introduced.

     When invoked as sudoedit, the -e option (described below), is implied.

     Security policies and audit plugins may log successful and failed
     attempts to run sudo.  If an I/O plugin is configured, the running
     command's input and output may be logged as well.

     The options are as follows:

     -A, --askpass
             Normally, if sudo requires a password, it will read it from the
             user's terminal.  If the -A (askpass) option is specified, a
             (possibly graphical) helper program is executed to read the
             user's password and output the password to the standard output.
             If the SUDO_ASKPASS environment variable is set, it specifies the
             path to the helper program.  Otherwise, if sudo.conf(5) contains
             a line specifying the askpass program, that value will be used.
             For example:

                 # Path to askpass helper program
                 Path askpass /usr/X11R6/bin/ssh-askpass

             If no askpass program is available, sudo will exit with an error.

     -B, --bell
             Ring the bell as part of the password prompt when a terminal is
             present.  This option has no effect if an askpass program is
             used.

     -b, --background
             Run the given command in the background.  It is not possible to
             use shell job control to manipulate background processes started
             by sudo.  Most interactive commands will fail to work properly in
             background mode.

     -C num, --close-from=num
             Close all file descriptors greater than or equal to num before
             executing a command.  Values less than three are not permitted.
             By default, sudo will close all open file descriptors other than
             standard input, standard output, and standard error when
             executing a command.  The security policy may restrict the user's
             ability to use this option.  The sudoers policy only permits use
             of the -C option when the administrator has enabled the
             closefrom_override option.

     -D directory, --chdir=directory
             Run the command in the specified directory instead of the current
             working directory.  The security policy may return an error if
             the user does not have permission to specify the working
             directory.

     -E, --preserve-env
             Indicates to the security policy that the user wishes to preserve
             their existing environment variables.  The security policy may
             return an error if the user does not have permission to preserve
             the environment.

     --preserve-env=list
             Indicates to the security policy that the user wishes to add the
             comma-separated list of environment variables to those preserved
             from the user's environment.  The security policy may return an
             error if the user does not have permission to preserve the
             environment.  This option may be specified multiple times.

     -e, --edit
             Edit one or more files instead of running a command.  In lieu of
             a path name, the string "sudoedit" is used when consulting the
             security policy.  If the user is authorized by the policy, the
             following steps are taken:

              1.   Temporary copies are made of the files to be edited with
                   the owner set to the invoking user.

              2.   The editor specified by the policy is run to edit the
                   temporary files.  The sudoers policy uses the SUDO_EDITOR,
                   VISUAL and EDITOR environment variables (in that order).
                   If none of SUDO_EDITOR, VISUAL or EDITOR are set, the first
                   program listed in the editor sudoers(5) option is used.

              3.   If they have been modified, the temporary files are copied
                   back to their original location and the temporary versions
                   are removed.

             To help prevent the editing of unauthorized files, the following
             restrictions are enforced unless explicitly allowed by the
             security policy:

              o  Symbolic links may not be edited (version 1.8.15 and higher).

              o  Symbolic links along the path to be edited are not followed
                 when the parent directory is writable by the invoking user
                 unless that user is root (version 1.8.16 and higher).

              o  Files located in a directory that is writable by the invoking
                 user may not be edited unless that user is root (version
                 1.8.16 and higher).

             Users are never allowed to edit device special files.

             If the specified file does not exist, it will be created.  Unlike
             most commands run by sudo, the editor is run with the invoking
             user's environment unmodified.  If the temporary file becomes
             empty after editing, the user will be prompted before it is
             installed.  If, for some reason, sudo is unable to update a file
             with its edited version, the user will receive a warning and the
             edited copy will remain in a temporary file.

     -g group, --group=group
             Run the command with the primary group set to group instead of
             the primary group specified by the target user's password
             database entry.  The group may be either a group name or a
             numeric group-ID (GID) prefixed with the `#' character (e.g.,
             `#0' for GID 0).  When running a command as a GID, many shells
             require that the `#' be escaped with a backslash (`\').  If no -u
             option is specified, the command will be run as the invoking
             user.  In either case, the primary group will be set to group.
             The sudoers policy permits any of the target user's groups to be
             specified via the -g option as long as the -P option is not in
             use.

     -H, --set-home
             Request that the security policy set the HOME environment
             variable to the home directory specified by the target user's
             password database entry.  Depending on the policy, this may be
             the default behavior.

     -h, --help
             Display a short help message to the standard output and exit.

     -h host, --host=host
             Run the command on the specified host if the security policy
             plugin supports remote commands. The sudoers plugin does not
             currently support running remote commands. This may also be used
             in conjunction with the -l option to list a user's privileges for
             the remote host.

     -i, --login
             Run the shell specified by the target user's password database
             entry as a login shell.  This means that login-specific resource
             files such as .profile, .bash_profile, or .login will be read by
             the shell.  If a command is specified, it is passed to the shell
             as a simple command using the -c option.  The command and any
             args are concatenated, separated by spaces, after escaping each
             character (including white space) with a backslash (`\') except
             for alphanumerics, underscores, hyphens, and dollar signs.  If no
             command is specified, an interactive shell is executed.  sudo
             attempts to change to that user's home directory before running
             the shell.  The command is run with an environment similar to the
             one a user would receive at log in.  Most shells behave
             differently when a command is specified as compared to an
             interactive session; consult the shell's manual for details.  The
             Command environment section in the sudoers(5) manual documents
             how the -i option affects the environment in which a command is
             run when the sudoers policy is in use.

     -K, --remove-timestamp
             Similar to the -k option, except that it removes every cached
             credential for the user, regardless of the terminal or parent
             process ID.  The next time sudo is run, a password must be
             entered if the security policy requires authentication.  It is
             not possible to use the -K option in conjunction with a command
             or other option.  This option does not require a password.  Not
             all security policies support credential caching.

     -k, --reset-timestamp
             When used without a command, invalidates the user's cached
             credentials for the current session.  The next time sudo is run
             in the session, a password must be entered if the security policy
             requires authentication.  By default, the sudoers policy uses a
             separate record in the credential cache for each terminal (or
             parent process ID if no terminal is present).  This prevents the
             -k option from interfering with sudo commands run in a different
             terminal session.  See the timestamp_type option in sudoers(5)
             for more information.  This option does not require a password,
             and was added to allow a user to revoke sudo permissions from a
             .logout file.

             When used in conjunction with a command or an option that may
             require a password, this option will cause sudo to ignore the
             user's cached credentials.  As a result, sudo will prompt for a
             password (if one is required by the security policy) and will not
             update the user's cached credentials.

             Not all security policies support credential caching.

     -l, --list
             If no command is specified, list the privileges for the invoking
             user (or the user specified by the -U option) on the current
             host.  A longer list format is used if this option is specified
             multiple times and the security policy supports a verbose output
             format.

             If a command is specified and is permitted by the security policy
             for the invoking user (or the, user specified by the -U option)
             on the current host, the fully-qualified path to the command is
             displayed along with any args. If -l is specified more than once
             (and the security policy supports it), the matching rule is
             displayed in a verbose format along with the command.  If a
             command is specified but not allowed by the policy, sudo will
             exit with a status value of 1.

     -N, --no-update
             Do not update the user's cached credentials, even if the user
             successfully authenticates.  Unlike the -k flag, existing cached
             credentials are used if they are valid.  To detect when the
             user's cached credentials are valid (or when no authentication is
             required), the following can be used:

                 sudo -Nnv

             Not all security policies support credential caching.

     -n, --non-interactive
             Avoid prompting the user for input of any kind.  If a password is
             required for the command to run, sudo will display an error
             message and exit.

     -P, --preserve-groups
             Preserve the invoking user's group vector unaltered.  By default,
             the sudoers policy will initialize the group vector to the list
             of groups the target user is a member of.  The real and effective
             group-IDs, however, are still set to match the target user.

     -p prompt, --prompt=prompt
             Use a custom password prompt with optional escape sequences.  The
             following percent (`%') escape sequences are supported by the
             sudoers policy:

             %H  expanded to the host name including the domain name (only if
                 the machine's host name is fully qualified or the fqdn option
                 is set in sudoers(5))

             %h  expanded to the local host name without the domain name

             %p  expanded to the name of the user whose password is being
                 requested (respects the rootpw, targetpw, and runaspw flags
                 in sudoers(5))

             %U  expanded to the login name of the user the command will be
                 run as (defaults to root unless the -u option is also
                 specified)

             %u  expanded to the invoking user's login name

             %%  two consecutive `%' characters are collapsed into a single
                 `%' character

             The custom prompt will override the default prompt specified by
             either the security policy or the SUDO_PROMPT environment
             variable.  On systems that use PAM, the custom prompt will also
             override the prompt specified by a PAM module unless the
             passprompt_override flag is disabled in sudoers.

     -R directory, --chroot=directory
             Change to the specified root directory (see chroot(8)) before
             running the command.  The security policy may return an error if
             the user does not have permission to specify the root directory.

     -S, --stdin
             Write the prompt to the standard error and read the password from
             the standard input instead of using the terminal device.

     -s, --shell
             Run the shell specified by the SHELL environment variable if it
             is set or the shell specified by the invoking user's password
             database entry.  If a command is specified, it is passed to the
             shell as a simple command using the -c option.  The command and
             any args are concatenated, separated by spaces, after escaping
             each character (including white space) with a backslash (`\')
             except for alphanumerics, underscores, hyphens, and dollar signs.
             If no command is specified, an interactive shell is executed.
             Most shells behave differently when a command is specified as
             compared to an interactive session; consult the shell's manual
             for details.

     -U user, --other-user=user
             Used in conjunction with the -l option to list the privileges for
             user instead of for the invoking user.  The security policy may
             restrict listing other users' privileges.  When using the sudoers
             policy, the -U option is restricted to the root user and users
             with either the "list" priviege for the specified user or the
             ability to run any command as root or user on the current host.

     -T timeout, --command-timeout=timeout
             Used to set a timeout for the command.  If the timeout expires
             before the command has exited, the command will be terminated.
             The security policy may restrict the user's ability to set
             timeouts.  The sudoers policy requires that user-specified
             timeouts be explicitly enabled.

     -u user, --user=user
             Run the command as a user other than the default target user
             (usually root).  The user may be either a user name or a numeric
             user-ID (UID) prefixed with the `#' character (e.g., `#0' for UID
             0).  When running commands as a UID, many shells require that the
             `#' be escaped with a backslash (`\').  Some security policies
             may restrict UIDs to those listed in the password database.  The
             sudoers policy allows UIDs that are not in the password database
             as long as the targetpw option is not set.  Other security
             policies may not support this.

     -V, --version
             Print the sudo version string as well as the version string of
             any configured plugins.  If the invoking user is already root,
             the -V option will display the options passed to configure when
             sudo was built; plugins may display additional information such
             as default options.

     -v, --validate
             Update the user's cached credentials, authenticating the user if
             necessary.  For the sudoers plugin, this extends the sudo timeout
             for another 5 minutes by default, but does not run a command.
             Not all security policies support cached credentials.

     --      The -- is used to delimit the end of the sudo options.
             Subsequent options are passed to the command.

     Options that take a value may only be specified once unless otherwise
     indicated in the description.  This is to help guard against problems
     caused by poorly written scripts that invoke sudo with user-controlled
     input.

     Environment variables to be set for the command may also be passed as
     options to sudo in the form VAR=value, for example
     LD_LIBRARY_PATH=/usr/local/pkg/lib.  Environment variables may be subject
     to restrictions imposed by the security policy plugin.  The sudoers
     policy subjects environment variables passed as options to the same
     restrictions as existing environment variables with one important
     difference.  If the setenv option is set in sudoers, the command to be
     run has the SETENV tag set or the command matched is ALL, the user may
     set variables that would otherwise be forbidden.  See sudoers(5) for more
     information.


COMMAND EXECUTION

     When sudo executes a command, the security policy specifies the execution
     environment for the command.  Typically, the real and effective user and
     group and IDs are set to match those of the target user, as specified in
     the password database, and the group vector is initialized based on the
     group database (unless the -P option was specified).

     The following parameters may be specified by security policy:

     o  real and effective user-ID

     o  real and effective group-ID

     o  supplementary group-IDs

     o  the environment list

     o  current working directory

     o  file creation mode mask (umask)

     o  scheduling priority (aka nice value)

   Process model
     There are two distinct ways sudo can run a command.

     If an I/O logging plugin is configured to log terminal I/O, or if the
     security policy explicitly requests it, a new pseudo-terminal ("pty") is
     allocated and fork(2) is used to create a second sudo process, referred
     to as the monitor.  The monitor creates a new terminal session with
     itself as the leader and the pty as its controlling terminal, calls
     fork(2) again, sets up the execution environment as described above, and
     then uses the execve(2) system call to run the command in the child
     process.  The monitor exists to relay job control signals between the
     user's terminal and the pty the command is being run in.  This makes it
     possible to suspend and resume the command normally.  Without the
     monitor, the command would be in what POSIX terms an "orphaned process
     group" and it would not receive any job control signals from the kernel.
     When the command exits or is terminated by a signal, the monitor passes
     the command's exit status to the main sudo process and exits.  After
     receiving the command's exit status, the main sudo process passes the
     command's exit status to the security policy's close function, as well as
     the close function of any configured audit plugin, and exits.  This mode
     is the default for sudo versions 1.9.14 and above when using the sudoers
     policy.

     If no pty is used, sudo calls fork(2), sets up the execution environment
     as described above, and uses the execve(2) system call to run the command
     in the child process.  The main sudo process waits until the command has
     completed, then passes the command's exit status to the security policy's
     close function, as well as the close function of any configured audit
     plugins, and exits.  As a special case, if the policy plugin does not
     define a close function, sudo will execute the command directly instead
     of calling fork(2) first.  The sudoers policy plugin will only define a
     close function when I/O logging is enabled, a pty is required, an SELinux
     role is specified, the command has an associated timeout, or the
     pam_session or pam_setcred options are enabled.  Both pam_session and
     pam_setcred are enabled by default on systems using PAM.  This mode is
     the default for sudo versions prior to 1.9.14 when using the sudoers
     policy.

     On systems that use PAM, the security policy's close function is
     responsible for closing the PAM session.  It may also log the command's
     exit status.

   Signal handling
     When the command is run as a child of the sudo process, sudo will relay
     signals it receives to the command.  The SIGINT and SIGQUIT signals are
     only relayed when the command is being run in a new pty or when the
     signal was sent by a user process, not the kernel.  This prevents the
     command from receiving SIGINT twice each time the user enters control-C.
     Some signals, such as SIGSTOP and SIGKILL, cannot be caught and thus will
     not be relayed to the command.  As a general rule, SIGTSTP should be used
     instead of SIGSTOP when you wish to suspend a command being run by sudo.

     As a special case, sudo will not relay signals that were sent by the
     command it is running.  This prevents the command from accidentally
     killing itself.  On some systems, the reboot(8) utility sends SIGTERM to
     all non-system processes other than itself before rebooting the system.
     This prevents sudo from relaying the SIGTERM signal it received back to
     reboot(8), which might then exit before the system was actually rebooted,
     leaving it in a half-dead state similar to single user mode.  Note,
     however, that this check only applies to the command run by sudo and not
     any other processes that the command may create.  As a result, running a
     script that calls reboot(8) or shutdown(8) via sudo may cause the system
     to end up in this undefined state unless the reboot(8) or shutdown(8) are
     run using the exec() family of functions instead of system() (which
     interposes a shell between the command and the calling process).

   Plugins
     Plugins may be specified via Plugin directives in the sudo.conf(5) file.
     They may be loaded as dynamic shared objects (on systems that support
     them), or compiled directly into the sudo binary.  If no sudo.conf(5)
     file is present, or if it doesn't contain any Plugin lines, sudo will use
     sudoers(5) for the policy, auditing, and I/O logging plugins.  See the
     sudo.conf(5) manual for details of the /opt/local/etc/sudo.conf file and
     the sudo_plugin(5) manual for more information about the sudo plugin
     architecture.


EXIT VALUE

     Upon successful execution of a command, the exit status from sudo will be
     the exit status of the program that was executed.  If the command
     terminated due to receipt of a signal, sudo will send itself the same
     signal that terminated the command.

     If the -l option was specified without a command, sudo will exit with a
     value of 0 if the user is allowed to run sudo and they authenticated
     successfully (as required by the security policy).  If a command is
     specified with the -l option, the exit value will only be 0 if the
     command is permitted by the security policy, otherwise it will be 1.

     If there is an authentication failure, a configuration/permission
     problem, or if the given command cannot be executed, sudo exits with a
     value of 1.  In the latter case, the error string is printed to the
     standard error.  If sudo cannot stat(2) one or more entries in the user's
     PATH, an error is printed to the standard error.  (If the directory does
     not exist or if it is not really a directory, the entry is ignored and no
     error is printed.)  This should not happen under normal circumstances.
     The most common reason for stat(2) to return "permission denied" is if
     you are running an automounter and one of the directories in your PATH is
     on a machine that is currently unreachable.


SECURITY NOTES

     sudo tries to be safe when executing external commands.

     To prevent command spoofing, sudo checks "." and "" (both denoting
     current directory) last when searching for a command in the user's PATH
     (if one or both are in the PATH).  Depending on the security policy, the
     user's PATH environment variable may be modified, replaced, or passed
     unchanged to the program that sudo executes.

     Users should never be granted sudo privileges to execute files that are
     writable by the user or that reside in a directory that is writable by
     the user.  If the user can modify or replace the command there is no way
     to limit what additional commands they can run.

     By default, sudo will only log the command it explicitly runs.  If a user
     runs a command such as `sudo su' or `sudo sh', subsequent commands run
     from that shell are not subject to sudo's security policy.  The same is
     true for commands that offer shell escapes (including most editors).  If
     I/O logging is enabled, subsequent commands will have their input and/or
     output logged, but there will not be traditional logs for those commands.
     Because of this, care must be taken when giving users access to commands
     via sudo to verify that the command does not inadvertently give the user
     an effective root shell.  For information on ways to address this, see
     the Preventing shell escapes section in sudoers(5).

     To prevent the disclosure of potentially sensitive information, sudo
     disables core dumps by default while it is executing (they are re-enabled
     for the command that is run).  This historical practice dates from a time
     when most operating systems allowed set-user-ID processes to dump core by
     default.  To aid in debugging sudo crashes, you may wish to re-enable
     core dumps by setting "disable_coredump" to false in the sudo.conf(5)
     file as follows:

         Set disable_coredump false

     See the sudo.conf(5) manual for more information.


ENVIRONMENT

     sudo utilizes the following environment variables.  The security policy
     has control over the actual content of the command's environment.

     EDITOR           Default editor to use in -e (sudoedit) mode if neither
                      SUDO_EDITOR nor VISUAL is set.

     MAIL             Set to the mail spool of the target user when the -i
                      option is specified, or when env_reset is enabled in
                      sudoers (unless MAIL is present in the env_keep list).

     HOME             Set to the home directory of the target user when the -i
                      or -H options are specified, when the -s option is
                      specified and set_home is set in sudoers, when
                      always_set_home is enabled in sudoers, or when env_reset
                      is enabled in sudoers and HOME is not present in the
                      env_keep list.

     LOGNAME          Set to the login name of the target user when the -i
                      option is specified, when the set_logname option is
                      enabled in sudoers, or when the env_reset option is
                      enabled in sudoers (unless LOGNAME is present in the
                      env_keep list).

     PATH             May be overridden by the security policy.

     SHELL            Used to determine shell to run with -s option.

     SUDO_ASKPASS     Specifies the path to a helper program used to read the
                      password if no terminal is available or if the -A option
                      is specified.

     SUDO_COMMAND     Set to the command run by sudo, including any args. The
                      args are truncated at 4096 characters to prevent a
                      potential execution error.

     SUDO_EDITOR      Default editor to use in -e (sudoedit) mode.

     SUDO_GID         Set to the group-ID of the user who invoked sudo.

     SUDO_HOME        Set to the home directory of the user who invoked sudo.

     SUDO_PROMPT      Used as the default password prompt unless the -p option
                      was specified.

     SUDO_PS1         If set, PS1 will be set to its value for the program
                      being run.

     SUDO_UID         Set to the user-ID of the user who invoked sudo.

     SUDO_USER        Set to the login name of the user who invoked sudo.

     USER             Set to the same value as LOGNAME, described above.

     VISUAL           Default editor to use in -e (sudoedit) mode if
                      SUDO_EDITOR is not set.


FILES

     /opt/local/etc/sudo.conf  sudo front-end configuration


EXAMPLES

     The following examples assume a properly configured security policy.

     To get a file listing of an unreadable directory:

         $ sudo ls /usr/local/protected

     To list the home directory of user yaz on a machine where the file system
     holding ~yaz is not exported as root:

         $ sudo -u yaz ls ~yaz

     To edit the index.html file as user www:

         $ sudoedit -u www ~www/htdocs/index.html

     To view system logs only accessible to root and users in the adm group:

         $ sudo -g adm more /var/log/syslog

     To run an editor as jim with a different primary group:

         $ sudoedit -u jim -g audio ~jim/sound.txt

     To shut down a machine:

         $ sudo shutdown -r +15 "quick reboot"

     To make a usage listing of the directories in the /home partition.  The
     commands are run in a sub-shell to allow the `cd' command and file
     redirection to work.

         $ sudo sh -c "cd /home ; du -s * | sort -rn > USAGE"


DIAGNOSTICS

     Error messages produced by sudo include:

     editing files in a writable directory is not permitted
           By default, sudoedit does not permit editing a file when any of the
           parent directories are writable by the invoking user.  This avoids
           a race condition that could allow the user to overwrite an
           arbitrary file.  See the sudoedit_checkdir option in sudoers(5) for
           more information.

     editing symbolic links is not permitted
           By default, sudoedit does not follow symbolic links when opening
           files.  See the sudoedit_follow option in sudoers(5) for more
           information.

     effective uid is not 0, is sudo installed setuid root?
           sudo was not run with root privileges.  The sudo binary must be
           owned by the root user and have the set-user-ID bit set.  Also, it
           must not be located on a file system mounted with the `nosuid'
           option or on an NFS file system that maps uid 0 to an unprivileged
           uid.

     effective uid is not 0, is sudo on a file system with the 'nosuid' option
           set or an NFS file system without root privileges?
           sudo was not run with root privileges.  The sudo binary has the
           proper owner and permissions but it still did not run with root
           privileges.  The most common reason for this is that the file
           system the sudo binary is located on is mounted with the `nosuid'
           option or it is an NFS file system that maps uid 0 to an
           unprivileged uid.

     fatal error, unable to load plugins
           An error occurred while loading or initializing the plugins
           specified in sudo.conf(5).

     invalid environment variable name
           One or more environment variable names specified via the -E option
           contained an equal sign (`=').  The arguments to the -E option
           should be environment variable names without an associated value.

     no password was provided
           When sudo tried to read the password, it did not receive any
           characters.  This may happen if no terminal is available (or the -S
           option is specified) and the standard input has been redirected
           from /dev/null.

     a terminal is required to read the password
           sudo needs to read the password but there is no mechanism available
           for it to do so.  A terminal is not present to read the password
           from, sudo has not been configured to read from the standard input,
           the -S option was not used, and no askpass helper has been
           specified either via the sudo.conf(5) file or the SUDO_ASKPASS
           environment variable.

     no writable temporary directory found
           sudoedit was unable to find a usable temporary directory in which
           to store its intermediate files.

     The "no new privileges" flag is set, which prevents sudo from running as
           root.
           sudo was run by a process that has the Linux "no new privileges"
           flag is set.  This causes the set-user-ID bit to be ignored when
           running an executable, which will prevent sudo from functioning.
           The most likely cause for this is running sudo within a container
           that sets this flag.  Check the documentation to see if it is
           possible to configure the container such that the flag is not set.

     sudo must be owned by uid 0 and have the setuid bit set
           sudo was not run with root privileges.  The sudo binary does not
           have the correct owner or permissions.  It must be owned by the
           root user and have the set-user-ID bit set.

     sudoedit is not supported on this platform
           It is only possible to run sudoedit on systems that support setting
           the effective user-ID.

     timed out reading password
           The user did not enter a password before the password timeout (5
           minutes by default) expired.

     you do not exist in the passwd database
           Your user-ID does not appear in the system passwd database.

     you may not specify environment variables in edit mode
           It is only possible to specify environment variables when running a
           command.  When editing a file, the editor is run with the user's
           environment unmodified.


SEE ALSO

     su(1), stat(2), login_cap(3), passwd(5), sudo.conf(5), sudo_plugin(5),
     sudo(8)


HISTORY

     See the HISTORY.md file in the sudo distribution
     (https://www.sudo.ws/about/history/) for a brief history of sudo.


AUTHORS

     Many people have worked on sudo over the years; this version consists of
     code written primarily by:

           Todd C. Miller

     See the CONTRIBUTORS.md file in the sudo distribution
     (https://www.sudo.ws/about/contributors/) for an exhaustive list of
     people who have contributed to sudo.


CAVEATS

     There is no easy way to prevent a user from gaining a root shell if that
     user is allowed to run arbitrary commands via sudo.  Also, many programs
     (such as editors) allow the user to run commands via shell escapes, thus
     avoiding sudo's checks.  However, on most systems it is possible to
     prevent shell escapes with the sudoers(5) plugin's noexec functionality.

     It is not meaningful to run the `cd' command directly via sudo, e.g.,

         $ sudo cd /usr/local/protected

     since when the command exits the parent process (your shell) will still
     be the same.  The -D option can be used to run a command in a specific
     directory.

     Running shell scripts via sudo can expose the same kernel bugs that make
     set-user-ID shell scripts unsafe on some operating systems (if your OS
     has a /dev/fd/ directory, set-user-ID shell scripts are generally safe).


BUGS

     If you believe you have found a bug in sudo, you can either file a bug
     report in the sudo bug database, https://bugzilla.sudo.ws/, or open an
     issue at https://github.com/sudo-project/sudo/issues.  If you would
     prefer to use email, messages may be sent to the sudo-workers mailing
     list, https://www.sudo.ws/mailman/listinfo/sudo-workers (public) or
     <sudo@sudo.ws> (private).

     Please not report security vulnerabilities through public GitHub issues,
     Bugzilla or mailing lists.  Instead, report them via email to
     <Todd.Miller@sudo.ws>.  You may encrypt your message with PGP if you
     would like, using the key found at https://www.sudo.ws/dist/PGPKEYS.


SUPPORT

     Limited free support is available via the sudo-users mailing list, see
     https://www.sudo.ws/mailman/listinfo/sudo-users to subscribe or search
     the archives.


DISCLAIMER

     sudo is provided "AS IS" and any express or implied warranties,
     including, but not limited to, the implied warranties of merchantability
     and fitness for a particular purpose are disclaimed.  See the LICENSE.md
     file distributed with sudo or https://www.sudo.ws/about/license/ for
     complete details.

Sudo 1.9.16                     August 9, 2023                     Sudo 1.9.16

sudo 1.9.16 - Generated Mon Sep 2 15:33:24 CDT 2024
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