SUDO(1m) MAINTENANCE COMMANDS SUDO(1m)
NNAAMMEE
sudo, sudoedit - execute a command as another user
SSYYNNOOPPSSIISS
ssuuddoo [--DD _l_e_v_e_l] --hh | --KK | --kk | --VV
ssuuddoo --vv [--AAkknnSS] [--aa _a_u_t_h___t_y_p_e] [--DD _l_e_v_e_l] [--gg _g_r_o_u_p _n_a_m_e|_#_g_i_d]
[--pp _p_r_o_m_p_t] [--uu _u_s_e_r _n_a_m_e|_#_u_i_d]
ssuuddoo --ll[[ll]] [--AAkknnSS] [--aa _a_u_t_h___t_y_p_e] [--DD _l_e_v_e_l] [--gg _g_r_o_u_p _n_a_m_e|_#_g_i_d]
[--pp _p_r_o_m_p_t] [--UU _u_s_e_r _n_a_m_e] [--uu _u_s_e_r _n_a_m_e|_#_u_i_d] [_c_o_m_m_a_n_d]
ssuuddoo [--AAbbEEHHnnPPSS] [--aa _a_u_t_h___t_y_p_e] [--CC _f_d] [--DD _l_e_v_e_l] [--cc _c_l_a_s_s|_-]
[--gg _g_r_o_u_p _n_a_m_e|_#_g_i_d] [--pp _p_r_o_m_p_t] [--rr _r_o_l_e] [--tt _t_y_p_e]
[--uu _u_s_e_r _n_a_m_e|_#_u_i_d] [VVAARR=_v_a_l_u_e] [--ii | --ss] [_c_o_m_m_a_n_d]
ssuuddooeeddiitt [--AAnnSS] [--aa _a_u_t_h___t_y_p_e] [--CC _f_d] [--cc _c_l_a_s_s|_-] [--DD _l_e_v_e_l]
[--gg _g_r_o_u_p _n_a_m_e|_#_g_i_d] [--pp _p_r_o_m_p_t] [--uu _u_s_e_r _n_a_m_e|_#_u_i_d] file ...
DDEESSCCRRIIPPTTIIOONN
ssuuddoo allows a permitted user to execute a _c_o_m_m_a_n_d as the superuser or
another user, as specified by the security policy. The real and
effective uid and gid 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 --PP option was specified).
ssuuddoo supports a plugin architecture for security policies and
input/output logging. Third parties can develop and distribute their
own policy and I/O logging modules to work seemlessly with the ssuuddoo
front end. The default security policy is _s_u_d_o_e_r_s, which is configured
via the file _/_e_t_c_/_s_u_d_o_e_r_s, or via LDAP. See the PLUGINS section for
more information.
The security policy determines what privileges, if any, a user has to
run ssuuddoo. The policy may require that users authenticate themselves
with a password or another authentication mechanism. If authentication
is required, ssuuddoo 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 _s_u_d_o_e_r_s security policy is 5
minutes.
Security policies may support credential caching to allow the user to
run ssuuddoo again for a period of time without requiring authentication.
The _s_u_d_o_e_r_s policy caches credentials for 5 minutes, unless overridden
in _s_u_d_o_e_r_s(4). By running ssuuddoo with the --vv option, a user can update
the cached credentials without running a _c_o_m_m_a_n_d.
When invoked as ssuuddooeeddiitt, the --ee option (described below), is implied.
Security policies may log successful and failed attempts to use ssuuddoo.
If an I/O plugin is configured, the running command's input and output
may be logged as well.
OOPPTTIIOONNSS
ssuuddoo accepts the following command line options:
-A Normally, if ssuuddoo requires a password, it will read it from
the user's terminal. If the --AA (_a_s_k_p_a_s_s) 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 _/_e_t_c_/_s_u_d_o_._c_o_n_f 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 _t_y_p_e The --aa (_a_u_t_h_e_n_t_i_c_a_t_i_o_n _t_y_p_e) option causes ssuuddoo to use the
specified authentication type when validating the user, as
allowed by _/_e_t_c_/_l_o_g_i_n_._c_o_n_f. The system administrator may
specify a list of sudo-specific authentication methods by
adding an "auth-sudo" entry in _/_e_t_c_/_l_o_g_i_n_._c_o_n_f. This
option is only available on systems that support BSD
authentication.
-b The --bb (_b_a_c_k_g_r_o_u_n_d) option tells ssuuddoo to run the given
command in the background. Note that if you use the --bb
option you cannot use shell job control to manipulate the
process. Most interactive commands will fail to work
properly in background mode.
-C _f_d Normally, ssuuddoo will close all open file descriptors other
than standard input, standard output and standard error.
The --CC (_c_l_o_s_e _f_r_o_m) option allows the user to specify a
starting point above the standard error (file descriptor
three). Values less than three are not permitted. The
security policy may restrict the user's ability to use the
--CC option. The _s_u_d_o_e_r_s policy only permits use of the --CC
option when the administrator has enabled the
_c_l_o_s_e_f_r_o_m___o_v_e_r_r_i_d_e option.
-c _c_l_a_s_s The --cc (_c_l_a_s_s) option causes ssuuddoo to run the specified
command with resources limited by the specified login
class. The _c_l_a_s_s argument can be either a class name as
defined in _/_e_t_c_/_l_o_g_i_n_._c_o_n_f, or a single '-' character.
Specifying a _c_l_a_s_s of - indicates that the command should
be run restricted by the default login capabilities for the
user the command is run as. If the _c_l_a_s_s argument
specifies an existing user class, the command must be run
as root, or the ssuuddoo command must be run from a shell that
is already root. This option is only available on systems
with BSD login classes.
-D _l_e_v_e_l Enable debugging of ssuuddoo plugins and ssuuddoo itself. The
_l_e_v_e_l may be a value from 1 through 9.
-E The --EE (_p_r_e_s_e_r_v_e _e_n_v_i_r_o_n_m_e_n_t) option indicates to the
security policy that the user wishes to preserve their
existing environment variables. The security policy may
return an error if the --EE option is specified and the user
does not have permission to preserve the environment.
-e The --ee (_e_d_i_t) option indicates that, instead of running a
command, the user wishes to edit one or more files. In
lieu of a command, 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 _s_u_d_o_e_r_s 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 _e_d_i_t_o_r
_s_u_d_o_e_r_s(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 ssuuddoo, the editor is
run with the invoking user's environment unmodified. If,
for some reason, ssuuddoo 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 _g_r_o_u_p Normally, ssuuddoo runs a command with the primary group set to
the one specified by the password database for the user the
command is being run as (by default, root). The --gg (_g_r_o_u_p)
option causes ssuuddoo to run the command with the primary
group set to _g_r_o_u_p instead. To specify a _g_i_d instead of a
_g_r_o_u_p _n_a_m_e, use _#_g_i_d. When running commands as a _g_i_d, many
shells require that the '#' be escaped with a backslash
('\'). If no --uu option is specified, the command will be
run as the invoking user (not root). In either case, the
primary group will be set to _g_r_o_u_p.
-H The --HH (_H_O_M_E) option requests that the security policy set
the HOME environment variable to the home directory of the
target user (root by default) as specified by the password
database. Depending on the policy, this may be the default
behavior.
-h The --hh (_h_e_l_p) option causes ssuuddoo to print a short help
message to the standard output and exit.
-i [command]
The --ii (_s_i_m_u_l_a_t_e _i_n_i_t_i_a_l _l_o_g_i_n) option runs the shell
specified by the password database entry of the target user
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 --cc option. If no command is
specified, an interactive shell is executed. ssuuddoo attempts
to change to that user's home directory before running the
shell. The security policy shall initialize the
environment to a minimal set of variables, similar to what
is present when a user logs in. The _C_o_m_m_a_n_d _E_n_v_i_r_o_n_m_e_n_t
section in the _s_u_d_o_e_r_s(4) manual documents how the --ii
option affects the environment in which a command is run
when the _s_u_d_o_e_r_s policy is in use.
-K The --KK (sure _k_i_l_l) option is like --kk 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 [command]
When used alone, the --kk (_k_i_l_l) option to ssuuddoo invalidates
the user's cached credentials. The next time ssuuddoo is run a
password will be required. This option does not require a
password and was added to allow a user to revoke ssuuddoo
permissions from a .logout file. Not all security policies
support credential caching.
When used in conjunction with a command or an option that
may require a password, the --kk option will cause ssuuddoo to
ignore the user's cached credentials. As a result, ssuuddoo
will prompt for a password (if one is required by the
security policy) and will not update the user's cached
credentials.
-l[l] [_c_o_m_m_a_n_d]
If no _c_o_m_m_a_n_d is specified, the --ll (_l_i_s_t) option will list
the allowed (and forbidden) commands for the invoking user
(or the user specified by the --UU option) on the current
host. If a _c_o_m_m_a_n_d 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
_c_o_m_m_a_n_d is specified but not allowed, ssuuddoo will exit with a
status value of 1. If the --ll option is specified with an ll
argument (i.e. --llll), or if --ll is specified multiple times,
a longer list format is used.
-n The --nn (_n_o_n_-_i_n_t_e_r_a_c_t_i_v_e) option prevents ssuuddoo from
prompting the user for a password. If a password is
required for the command to run, ssuuddoo will display an error
messages and exit.
-P The --PP (_p_r_e_s_e_r_v_e _g_r_o_u_p _v_e_c_t_o_r) option causes ssuuddoo to
preserve the invoking user's group vector unaltered. By
default, the _s_u_d_o_e_r_s policy will initialize the group
vector to the list of groups the target user is in. The
real and effective group IDs, however, are still set to
match the target user.
-p _p_r_o_m_p_t The --pp (_p_r_o_m_p_t) option allows you to override the default
password prompt and use a custom one. The following
percent (`%') escapes are supported by the _s_u_d_o_e_r_s policy:
%H expanded to the host name including the domain name (on
if the machine's host name is fully qualified or the
_f_q_d_n option is set in _s_u_d_o_e_r_s(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 _r_o_o_t_p_w, _t_a_r_g_e_t_p_w and
_r_u_n_a_s_p_w flags in _s_u_d_o_e_r_s(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 prompt specified by the --pp option will override the
system password prompt on systems that support PAM unless
the _p_a_s_s_p_r_o_m_p_t___o_v_e_r_r_i_d_e flag is disabled in _s_u_d_o_e_r_s.
-r _r_o_l_e The --rr (_r_o_l_e) option causes the new (SELinux) security
context to have the role specified by _r_o_l_e.
-S The --SS (_s_t_d_i_n) option causes ssuuddoo to read the password from
the standard input instead of the terminal device. The
password must be followed by a newline character.
-s [command]
The --ss (_s_h_e_l_l) option runs the shell specified by the _S_H_E_L_L
environment variable if it is set or the shell as specified
in the password database. If a command is specified, it is
passed to the shell for execution via the shell's --cc
option. If no command is specified, an interactive shell
is executed.
-t _t_y_p_e The --tt (_t_y_p_e) option causes the new (SELinux) security
context to have the type specified by _t_y_p_e. If no type is
specified, the default type is derived from the specified
role.
-U _u_s_e_r The --UU (_o_t_h_e_r _u_s_e_r) option is used in conjunction with the
--ll option to specify the user whose privileges should be
listed. The security policy may restrict listing other
users' privileges. The _s_u_d_o_e_r_s policy only allows root or
a user with the ALL privilege on the current host to use
this option.
-u _u_s_e_r The --uu (_u_s_e_r) option causes ssuuddoo to run the specified
command as a user other than _r_o_o_t. To specify a _u_i_d
instead of a _u_s_e_r _n_a_m_e, use _#_u_i_d. When running commands as
a _u_i_d, many shells require that the '#' be escaped with a
backslash ('\'). Security policies may restrict _u_i_ds to
those listed in the password database. The _s_u_d_o_e_r_s policy
allows _u_i_ds that are not in the password database as long
as the _t_a_r_g_e_t_p_w option is not set. Other security policies
may not support this.
-V The --VV (_v_e_r_s_i_o_n) option causes ssuuddoo to print its version
string and the version string of the security policy plugin
and any I/O plugins. If the invoking user is already root
the --VV option will display the arguments passed to
configure when _s_u_d_o was built and plugins may display more
verbose information such as default options.
-v When given the --vv (_v_a_l_i_d_a_t_e) option, ssuuddoo will update the
user's cached credentials, authenticating the user's
password if necessary. For the _s_u_d_o_e_r_s plugin, this
extends the ssuuddoo timeout for another 5 minutes (or whatever
the timeout is set to in _s_u_d_o_e_r_s) but does not run a
command. Not all security policies support cached
credentials.
-- The ---- option indicates that ssuuddoo 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 VVAARR=_v_a_l_u_e, e.g.
LLDD__LLIIBBRRAARRYY__PPAATTHH=_/_u_s_r_/_l_o_c_a_l_/_p_k_g_/_l_i_b. Variables passed on the command
line are subject to the same restrictions as normal environment
variables with one important exception. If the _s_e_t_e_n_v option is set in
_s_u_d_o_e_r_s, the command to be run has the SETENV tag set or the command
matched is ALL, the user may set variables that would overwise be
forbidden. See _s_u_d_o_e_r_s(4) for more information.
PPLLUUGGIINNSS
Plugins are dynamically loaded based on the contents of the
_/_e_t_c_/_s_u_d_o_._c_o_n_f file. If no _/_e_t_c_/_s_u_d_o_._c_o_n_f file is present, or it
contains no Plugin lines, ssuuddoo will use the traditional _s_u_d_o_e_r_s
security policy and I/O logging, which corresponds to the following
_/_e_t_c_/_s_u_d_o_._c_o_n_f file.
#
# Default /etc/sudo.conf file
#
# Format:
# Plugin plugin_name plugin_path
# Path askpass /path/to/askpass
# Path noexec /path/to/noexec.so
#
# The plugin_path is relative to /usr/local/libexec unless
# fully qualified.
# The plugin_name corresponds to a global symbol in the plugin
# that contains the plugin interface structure.
#
Plugin policy_plugin sudoers.so
Plugin io_plugin sudoers.so
A Plugin line consists of the Plugin keyword, followed by the
_s_y_m_b_o_l___n_a_m_e and the _p_a_t_h to the shared object containing the plugin.
The _s_y_m_b_o_l___n_a_m_e is the name of the struct policy_plugin or struct
io_plugin in the plugin shared object. The _p_a_t_h may be fully qualified
or relative. If not fully qualified it is relative to the
_/_u_s_r_/_l_o_c_a_l_/_l_i_b_e_x_e_c directory. Any additional parameters after the _p_a_t_h
are ignored. Lines that don't begin with Plugin or Path are silently
ignored
For more information, see the _s_u_d_o___p_l_u_g_i_n(1m) manual.
PPAATTHHSS
A Path line consists of the Path keyword, followed by the name of the
path to set and its value. E.g.
Path noexec /usr/local/libexec/sudo_noexec.so
Path askpass /usr/X11R6/bin/ssh-askpass
The following plugin-agnostic paths may be set in the _/_e_t_c_/_s_u_d_o_._c_o_n_f
file.
askpass The fully qualified path to a helper program used to
read the user's password when no terminal is available.
This may be the case when ssuuddoo is executed from a
graphical (as opposed to text-based) application. The
program specified by _a_s_k_p_a_s_s should display the
argument passed to it as the prompt and write the
user's password to the standard output. The value of
_a_s_k_p_a_s_s may be overridden by the SUDO_ASKPASS
environment variable.
noexec The fully-qualified path to a shared library containing
dummy versions of the _e_x_e_c_v_(_), _e_x_e_c_v_e_(_) and _f_e_x_e_c_v_e_(_)
library functions that just return an error. This is
used to implement the _n_o_e_x_e_c functionality on systems
that support LD_PRELOAD or its equivalent. Defaults to
_/_u_s_r_/_l_o_c_a_l_/_l_i_b_e_x_e_c_/_s_u_d_o___n_o_e_x_e_c_._s_o.
RREETTUURRNN VVAALLUUEESS
Upon successful execution of a program, the exit status from ssuuddoo will
simply be the exit status of the program that was executed.
Otherwise, ssuuddoo exits with a value of 1 if there is a
configuration/permission problem or if ssuuddoo cannot execute the given
command. In the latter case the error string is printed to the
standard error. If ssuuddoo cannot _s_t_a_t(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 _s_t_a_t(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.
SSEECCUURRIITTYY NNOOTTEESS
ssuuddoo tries to be safe when executing external commands.
To prevent command spoofing, ssuuddoo 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 _n_o_t modified and is passed unchanged to the
program that ssuuddoo executes.
Please note that ssuuddoo 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 ssuuddoo'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 ssuuddoo 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
_s_u_d_o_e_r_s(4).
EENNVVIIRROONNMMEENNTT
ssuuddoo utilizes the following environment variables. The security policy
has control over the content of the command's environment.
EDITOR Default editor to use in --ee (sudoedit) mode if neither
SUDO_EDITOR nor VISUAL is set
MAIL In --ii mode or when _e_n_v___r_e_s_e_t is enabled in _s_u_d_o_e_r_s, set
to the mail spool of the target user
HOME Set to the home directory of the target user if --ii or
--HH are specified, _e_n_v___r_e_s_e_t or _a_l_w_a_y_s___s_e_t___h_o_m_e are set
in _s_u_d_o_e_r_s, or when the --ss option is specified and
_s_e_t___h_o_m_e is set in _s_u_d_o_e_r_s
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 --ee (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 of the user who invoked sudo
USER Set to the target user (root unless the --uu option is
specified)
VISUAL Default editor to use in --ee (sudoedit) mode if
SUDO_EDITOR is not set
FFIILLEESS
_/_e_t_c_/_s_u_d_o_._c_o_n_f ssuuddoo plugin and path configuration
EEXXAAMMPPLLEESS
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 _i_n_d_e_x_._h_t_m_l 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 shutdown 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"
SSEEEE AALLSSOO
_g_r_e_p(1), _s_u(1), _s_t_a_t(2), _l_o_g_i_n___c_a_p(3), _p_a_s_s_w_d(4), _s_u_d_o_e_r_s(4),
_s_u_d_o___p_l_u_g_i_n(1m), _s_u_d_o_r_e_p_l_a_y(1m), _v_i_s_u_d_o(1m)
AAUUTTHHOORRSS
Many people have worked on ssuuddoo over the years; this version consists
of code written primarily by:
Todd C. Miller
See the HISTORY file in the ssuuddoo distribution or visit
http://www.sudo.ws/sudo/history.html for a short history of ssuuddoo.
CCAAVVEEAATTSS
There is no easy way to prevent a user from gaining a root shell if
that user is allowed to run arbitrary commands via ssuuddoo. Also, many
programs (such as editors) allow the user to run commands via shell
escapes, thus avoiding ssuuddoo's checks. However, on most systems it is
possible to prevent shell escapes with the _s_u_d_o_e_r_s(4) module's _n_o_e_x_e_c
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 ssuuddoo 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).
BBUUGGSS
If you feel you have found a bug in ssuuddoo, please submit a bug report at
http://www.sudo.ws/sudo/bugs/
SSUUPPPPOORRTT
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.
DDIISSCCLLAAIIMMEERR
ssuuddoo 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 ssuuddoo or
http://www.sudo.ws/sudo/license.html for complete details.
1.8.3 September 16, 2011 SUDO(1m)
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