Provided by: sudo-ldap_1.9.14p2-1ubuntu1_amd64 bug

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]
          [-r role] [-t type] [-T timeout] [-u user] [VAR=value] [-i | -s] [command [arg ...]]
     sudoedit [-ABkNnS] [-C num] [-D directory] [-g group] [-h host] [-p prompt] [-R directory]
          [-r role] [-t type] [-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 /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 15 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 visudo(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:

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

                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).

                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, the fully-
             qualified path to the command is displayed along with any args. 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.

     -r role, --role=role
             Run the command with an SELinux security context that includes the specified role.

     -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.

     -t type, --type=type
             Run the command with an SELinux security context that includes the specified type.
             If no type is specified, the default type is derived from the role.

     -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 15 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:

       real and effective user-ID

       real and effective group-ID

       supplementary group-IDs

       the environment list

       current working directory

       file creation mode mask (umask)

       SELinux role and type

       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 /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_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

     /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), sudoers(5),
     sudoers_timestamp(5), sudoreplay(8), visudo(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 submit a bug report at
     https://bugzilla.sudo.ws/

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.