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sudo(1m)

SUDO(1m)                    System Manager's Manual                   SUDO(1m)



NAME
       sudo, sudoedit - execute a command as another user

SYNOPSIS
       sudo -h | -K | -k | -V
       sudo -v [-AknS] [-g group] [-h host] [-p prompt] [-u user]
       sudo -l [-AknS] [-g group] [-h host] [-p prompt] [-U user] [-u user]
            [command]
       sudo [-AbEHnPS] [-C num] [-g group] [-h host] [-p prompt] [-u user]
            [VAR=value] [-i | -s] [command]
       sudoedit [-AknS] [-C num] [-g group] [-h host] [-p prompt] [-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.

       sudo supports a plugin architecture for security policies and
       input/output logging.  Third parties can develop and distribute their
       own policy and I/O logging 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 5
       minutes.

       Security policies may support credential caching to allow the user to
       run sudo again for a period of time without requiring authentication.
       The sudoers policy caches credentials for 5 minutes, unless overridden
       in sudoers(4).  By running sudo with the -v option, a user can update
       the cached credentials without running a command.

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

       Security policies may log successful and failed attempts to use 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(4) 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.

       -a type, --auth-type=type
                   Use the specified BSD authentication type when validating
                   the user, if allowed by /etc/login.conf.  The system
                   administrator may specify a list of sudo-specific
                   authentication methods by adding an ``auth-sudo'' entry in
                   /etc/login.conf.  This option is only available on systems
                   that support BSD authentication.

       -b, --background
                   Run the given command in the background.  Note that 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.

       -c class, --login-class=class
                   Run the command with resource limits and scheduling
                   priority of the specified login class.  The class argument
                   can be either a class name as defined in /etc/login.conf,
                   or a single `-' character.  If class is -, the default
                   login class of the target user will be used.  Otherwise,
                   the command must be run as the superuser (user ID 0), or
                   sudo must be run from a shell that is already running as
                   the superuser.  If the command is being run as a login
                   shell, additional /etc/login.conf settings, such as the
                   umask and environment variables, will be applied, if
                   present.  This option is only available on systems with BSD
                   login classes.

       -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.

       -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(4) 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.

                   If the specified file does not exist, it will be created.
                   Note that unlike most commands run by sudo, the editor is
                   run with the invoking user's environment unmodified.  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.

       -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.  Note that 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 or .login will be
                   read by the shell.  If a command is specified, it is passed
                   to the shell for execution via the shell's -c option.  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.  The Command Environment section in the sudoers(4)
                   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 the user's
                   cached credentials entirely and may not be used 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.  In other words, the next time sudo is run a
                   password will be required.  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 allowed (and
                   forbidden) commands 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 command line arguments.  If
                   command is specified but not allowed, sudo will exit with a
                   status value of 1.

       -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 (on
                       if the machine's host name is fully qualified or the
                       fqdn option is set in sudoers(4))

                   %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(4))

                   %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 system password prompt
                   on systems that support PAM unless the passprompt_override
                   flag is disabled in sudoers.

       -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.  The password must be followed by a
                   newline character.

       -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 for execution via the shell's -c
                   option.  If no command is specified, an interactive shell
                   is executed.

       -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.  The sudoers policy only allows root or a user
                   with the ALL privilege on the current host to use this
                   option.

       -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 the security policy plugin and any I/O plugins.  If the
                   invoking user is already root the -V option will display
                   the arguments passed to configure when sudo was built and
                   plugins may display more verbose 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 -- option indicates that sudo should stop processing
                   command line arguments.

       Environment variables to be set for the command may also be passed on
       the command line in the form of VAR=value, e.g.
       LD_LIBRARY_PATH=/usr/local/pkg/lib.  Variables passed on the command
       line are subject to restrictions imposed by the security policy plugin.
       The sudoers policy subjects variables passed on the command line to the
       same restrictions as normal environment variables with one important
       exception.  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(4) 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   Solaris project

       o   Solaris privileges

       o   scheduling priority (aka nice value)

   Process model
       When sudo runs a command, it calls fork(2), sets up the execution
       environment as described above, and calls the execve system call 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 and exits.  If an I/O logging plugin is
       configured or if the security policy explicitly requests it, a new
       pseudo-terminal (``pty'') is created and a second sudo process is used
       to relay job control signals between the user's existing pty and the
       new pty the command is being run in.  This extra process makes it
       possible to, for example, suspend and resume the command.  Without it,
       the command would be in what POSIX terms an ``orphaned process group''
       and it would not receive any job control signals.  As a special case,
       if the policy plugin does not define a close function and no pty is
       required, 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, or the
       pam_session or pam_setcred options are enabled.  Note that pam_session
       and pam_setcred are enabled by default on systems using PAM.

   Signal handling
       When the command is run as a child of the sudo process, sudo will relay
       signals it receives to the command.  Unless the command is being run in
       a new pty, the SIGHUP, SIGINT and SIGQUIT signals are not relayed
       unless they are sent by a user process, not the kernel.  Otherwise, the
       command would receive SIGINT twice every time the user entered 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(1m) command 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(1m), 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(1m) or
       shutdown(1m) via sudo may cause the system to end up in this undefined
       state unless the reboot(1m) or shutdown(1m) are run using the exec()
       family of functions instead of system() (which interposes a shell
       between the command and the calling process).

       If no I/O logging plugins are loaded and the policy plugin has not
       defined a close() function, set a command timeout or required that the
       command be run in a new pty, sudo may execute the command directly
       instead of running it as a child process.

   Plugins
       Plugins may be specified via Plugin directives in the sudo.conf(4)
       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(4) file is present, or it contains no Plugin lines, sudo will
       use the traditional sudoers security policy and I/O logging.  See the
       sudo.conf(4) manual for details of the /etc/sudo.conf file and the
       sudo_plugin(1m) manual for more information about the sudo plugin
       architecture.

EXIT VALUE
       Upon successful execution of a program, the exit status from sudo will
       simply be the exit status of the program that was executed.

       Otherwise, sudo exits with a value of 1 if there is a
       configuration/permission problem or if sudo cannot execute the given
       command.  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 on stderr.  (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).  Note, however, that the actual PATH
       environment variable is not modified and is passed unchanged to the
       program that sudo executes.

       Please note that sudo will normally 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 more
       information, please see the PREVENTING SHELL ESCAPES section in
       sudoers(4).

       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).  To aid in debugging sudo
       crashes, you may wish to re-enable core dumps by setting
       ``disable_coredump'' to false in the sudo.conf(4) file as follows:

             Set disable_coredump false

       See the sudo.conf(4) 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             In -i mode or when env_reset is enabled in sudoers,
                        set to the mail spool of the target user.

       HOME             Set to the home directory of the target user if -i or
                        -H are specified, env_reset or always_set_home are set
                        in sudoers, or when the -s option is specified and
                        set_home is set in sudoers.

       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.

       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.

       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 target user (root unless the -u option is
                        specified).

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

FILES
       /etc/sudo.conf            sudo front end configuration

EXAMPLES
       Note: 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:

             $ sudo -u www vi ~www/htdocs/index.html

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

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

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

             $ sudo -u jim -g audio vi ~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.
       Note that this runs the commands in a sub-shell to make the cd and file
       redirection work.

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


ATTRIBUTES
       See attributes(5) for descriptions of the following attributes:


       box; cbp-1 | cbp-1 l | l .  ATTRIBUTE TYPE ATTRIBUTE VALUE =
       Availability   security/sudo = Stability Uncommitted

SEE ALSO
       su(1), stat(2), passwd(4), sudo.conf(4), sudoers(4), sudo_plugin(1m),
       sudoreplay(1m), visudo(1m)

HISTORY
       See the HISTORY file in the sudo distribution
       (http://www.sudo.ws/sudo/history.html) 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 file in the sudo distribution
       (http://www.sudo.ws/sudo/contributors.html) 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(4) 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.  Please see the EXAMPLES section for more information.

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

BUGS
       If you feel you have found a bug in sudo, please submit a bug report at
       http://www.sudo.ws/sudo/bugs/

SUPPORT
       Limited free support is available via the sudo-users mailing list, see
       http://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 file distributed with sudo or
       http://www.sudo.ws/sudo/license.html for complete details.



NOTES
       This software was built from source available at
       https://java.net/projects/solaris-userland.  The original community
       source was downloaded from
       http://www.sudo.ws/sudo/dist/sudo-1.8.9p5.tar.gz

       Further information about this software can be found on the open source
       community website at http://www.sudo.ws/.



Sudo 1.8.9p5                   December 8, 2013                       SUDO(1m)
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