SUDO(1m) System Manager's Manual SUDO(1m)
NNAAMMEE
ssuuddoo, ssuuddooeeddiitt - execute a command as another user
SSYYNNOOPPSSIISS
ssuuddoo --hh | --KK | --kk | --LL | --VV
ssuuddoo --vv [--AAkknnSS] [--aa _a_u_t_h___t_y_p_e] [--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[_l] [--AAkknnSS] [--aa _a_u_t_h___t_y_p_e] [--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] [--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 | _-]
[--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 _s_u_d_o_e_r_s file. See the _C_O_M_M_A_N_D
_E_X_E_C_U_T_I_O_N section below for more details.
ssuuddoo determines who is an authorized user by consulting the file
_/_e_t_c_/_s_u_d_o_e_r_s. By running ssuuddoo with the --vv option, a user can update the
time stamp without running a _c_o_m_m_a_n_d. If authentication is required,
ssuuddoo will exit if the user's password is not entered within a
configurable time limit. The default password prompt timeout is 5
minutes.
When invoked as ssuuddooeeddiitt, the --ee option (described below), is implied.
The options are as follows:
--AA 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,
the value specified by the _a_s_k_p_a_s_s option in sudoers(4) is
used. If no askpass program is available, ssuuddoo will exit
with an error.
--aa _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.
--bb 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.
--CC _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. This option is
only available when the administrator has enabled the
_c_l_o_s_e_f_r_o_m___o_v_e_r_r_i_d_e option in sudoers(4).
--cc _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.
--EE The --EE (_p_r_e_s_e_r_v_e _e_n_v_i_r_o_n_m_e_n_t) option will override the
_e_n_v___r_e_s_e_t option in sudoers(4). It is only available when
either the matching command has the SETENV tag or the _s_e_t_e_n_v
option is set in sudoers(4). ssuuddoo will return an error if
the --EE option is specified and the user does not have
permission to preserve the environment.
--ee 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 _s_u_d_o_e_r_s file. If the user is authorized by _s_u_d_o_e_r_s, 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 SUDO_EDITOR, VISUAL or
EDITOR environment variables (in that order) is run to
edit the temporary files. If none of SUDO_EDITOR,
VISUAL or EDITOR are set, the first program listed in
the _e_d_i_t_o_r 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 _s_u_d_o, 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.
--gg _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.
--HH The --HH (_H_O_M_E) option option sets the HOME environment
variable to the home directory of the target user (root by
default) as specified by the password database. The default
handling of the HOME environment variable depends on
sudoers(4) settings. By default, ssuuddoo will set HOME if
_e_n_v___r_e_s_e_t or _a_l_w_a_y_s___s_e_t___h_o_m_e are set, or if _s_e_t___h_o_m_e is set
and the --ss option is specified on the command line.
--hh The --hh (_h_e_l_p) option causes ssuuddoo to print a short help
message to the standard output and exit.
--ii [_c_o_m_m_a_n_d]
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 _._p_r_o_f_i_l_e or _._l_o_g_i_n 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. It also initializes 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 below documents in detail how
the --ii option affects the environment in which a command is
run.
--KK The --KK (sure _k_i_l_l) option is like --kk except that it removes
the user's time stamp file entirely and may not be used in
conjunction with a command or other option. This option does
not require a password.
--kk [_c_o_m_m_a_n_d]
When used alone, the --kk (_k_i_l_l) option to ssuuddoo invalidates the
user's time stamp file. 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 _._l_o_g_o_u_t file.
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 time stamp file. As a result, ssuuddoo will prompt
for a password (if one is required by _s_u_d_o_e_r_s) and will not
update the user's time stamp file.
--LL The --LL (_l_i_s_t defaults) option will list the parameters that
may be set in a _D_e_f_a_u_l_t_s line along with a short description
for each. This option will be removed from a future version
of ssuuddoo.
--ll[ll] [_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 _s_u_d_o_e_r_s, 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 _l argument (i.e. --llll), or if --ll
is specified multiple times, a longer list format is used.
--nn 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 message and exit.
--PP 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, ssuuddoo
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.
--pp _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:
%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 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 _r_o_o_t_p_w, _t_a_r_g_e_t_p_w, and _r_u_n_a_s_p_w
flags in sudoers(4))
%U expanded to the login name of the user the command will
be run as (defaults to root unless the --uu 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.
--rr _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.
--SS 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.
--ss [_c_o_m_m_a_n_d]
The --ss (_s_h_e_l_l) option runs the shell specified by the SHELL
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.
--tt _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.
--UU _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.
Only root or a user with the ALL privilege on the current
host may use this option.
--uu _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, _#_u_i_d. When running commands as a _u_i_d, many shells
require that the `#' be escaped with a backslash (`\'). Note
that if the _t_a_r_g_e_t_p_w Defaults option is set (see sudoers(4)),
it is not possible to run commands with a uid not listed in
the password database.
--VV The --VV (_v_e_r_s_i_o_n) option causes ssuuddoo to print its version
string and exit. If the invoking user is already root the --VV
option will display the arguments passed to configure when
ssuuddoo was built as well a list of the defaults ssuuddoo was
compiled with as well as the machine's local network
addresses.
--vv When given the --vv (_v_a_l_i_d_a_t_e) option, ssuuddoo will update the
user's time stamp file, authenticating the user's password if
necessary. 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.
---- 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 otherwise be forbidden. See
sudoers(4) for more information.
AAuutthheennttiiccaattiioonn aanndd llooggggiinngg
ssuuddoo requires that most users authenticate themselves by default. A
password is not required if the invoking user is root, if the target user
is the same as the invoking user, or if the authentication has been
disabled for the user or command in the _s_u_d_o_e_r_s file. Unlike su(1), when
ssuuddoo requires authentication, it validates the invoking user's
credentials, not the target user's (or root's) credentials. This can be
changed via the _r_o_o_t_p_w, _t_a_r_g_e_t_p_w and _r_u_n_a_s_p_w Defaults entries in _s_u_d_o_e_r_s.
If a user who is not listed in _s_u_d_o_e_r_s tries to run a command via ssuuddoo,
mail is sent to the proper authorities. The address used for such mail
is configurable via the _m_a_i_l_t_o _s_u_d_o_e_r_s Defaults entry and defaults to
root.
Note that mail will not be sent if an unauthorized user tries to run ssuuddoo
with the --ll or --vv option. This allows users to determine for themselves
whether or not they are allowed to use ssuuddoo.
If ssuuddoo is run by root and the SUDO_USER environment variable is set, its
value will be used to determine who the actual user is. This can be used
by a user to log commands through ssuuddoo even when a root shell has been
invoked. It also allows the --ee option to remain useful even when invoked
via a sudo-run script or program. Note, however, that the _s_u_d_o_e_r_s lookup
is still done for root, not the user specified by SUDO_USER.
ssuuddoo uses time stamp files for credential caching. Once a user has been
authenticated, the time stamp is updated and the user may then use sudo
without a password for a short period of time (5 minutes unless
overridden by the _t_i_m_e_o_u_t option). By default, ssuuddoo uses a tty-based
time stamp which means that there is a separate time stamp for each of a
user's login sessions. The _t_t_y___t_i_c_k_e_t_s option can be disabled to force
the use of a single time stamp for all of a user's sessions.
ssuuddoo can log both successful and unsuccessful attempts (as well as
errors) to syslog(3), a log file, or both. By default, ssuuddoo will log via
syslog(3) but this is changeable via the _s_y_s_l_o_g and _l_o_g_f_i_l_e Defaults
settings.
ssuuddoo also supports logging a command's input and output streams. I/O
logging is not on by default but can be enabled using the _l_o_g___i_n_p_u_t and
_l_o_g___o_u_t_p_u_t Defaults flags as well as the LOG_INPUT and LOG_OUTPUT command
tags.
CCoommmmaanndd eennvviirroonnmmeenntt
Since environment variables can influence program behavior, ssuuddoo provides
a means to restrict which variables from the user's environment are
inherited by the command to be run. There are two distinct ways _s_u_d_o_e_r_s
can be configured to handle with environment variables.
By default, the _e_n_v___r_e_s_e_t option is enabled. This causes commands to be
executed with a new, minimal environment. On AIX (and Linux systems
without PAM), the environment is initialized with the contents of the
_/_e_t_c_/_e_n_v_i_r_o_n_m_e_n_t file. On BSD systems, if the _u_s_e___l_o_g_i_n_c_l_a_s_s option is
enabled, the environment is initialized based on the _p_a_t_h and _s_e_t_e_n_v
settings in _/_e_t_c_/_l_o_g_i_n_._c_o_n_f. The new environment contains the TERM,
PATH, HOME, MAIL, SHELL, LOGNAME, USER, USERNAME and SUDO_* variables in
addition to variables from the invoking process permitted by the
_e_n_v___c_h_e_c_k and _e_n_v___k_e_e_p options. This is effectively a whitelist for
environment variables.
If, however, the _e_n_v___r_e_s_e_t option is disabled, any variables not
explicitly denied by the _e_n_v___c_h_e_c_k and _e_n_v___d_e_l_e_t_e options are inherited
from the invoking process. In this case, _e_n_v___c_h_e_c_k and _e_n_v___d_e_l_e_t_e behave
like a blacklist. Since it is not possible to blacklist all potentially
dangerous environment variables, use of the default _e_n_v___r_e_s_e_t behavior is
encouraged.
In all cases, environment variables with a value beginning with () are
removed as they could be interpreted as bbaasshh functions. The list of
environment variables that ssuuddoo allows or denies is contained in the
output of ``sudo -V'' when run as root.
Note that the dynamic linker on most operating systems will remove
variables that can control dynamic linking from the environment of setuid
executables, including ssuuddoo. Depending on the operating system this may
include _RLD*, DYLD_*, LD_*, LDR_*, LIBPATH, SHLIB_PATH, and others.
These type of variables are removed from the environment before ssuuddoo even
begins execution and, as such, it is not possible for ssuuddoo to preserve
them.
As a special case, if ssuuddoo's --ii option (initial login) is specified, ssuuddoo
will initialize the environment regardless of the value of _e_n_v___r_e_s_e_t.
The DISPLAY, PATH and TERM variables remain unchanged; HOME, MAIL, SHELL,
USER, and LOGNAME are set based on the target user. On AIX (and Linux
systems without PAM), the contents of _/_e_t_c_/_e_n_v_i_r_o_n_m_e_n_t are also included.
On BSD systems, if the _u_s_e___l_o_g_i_n_c_l_a_s_s option is enabled, the _p_a_t_h and
_s_e_t_e_n_v variables in _/_e_t_c_/_l_o_g_i_n_._c_o_n_f are also applied. All other
environment variables are removed.
Finally, if the _e_n_v___f_i_l_e option is defined, any variables present in that
file will be set to their specified values as long as they would not
conflict with an existing environment variable.
CCOOMMMMAANNDD EEXXEECCUUTTIIOONN
When ssuuddoo executes a command, the _s_u_d_o_e_r_s file specifies the execution
envionment for the command. Typically, 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).
The _s_u_d_o_e_r_s file settings affect the following execution parameters:
oo real and effective user ID
oo real and effective group ID
oo supplementary group IDs
oo the environment list
oo SELinux role and type
oo Solaris project
oo Solaris privileges
oo BSD login class
oo file creation mode mask (umask)
See the _C_o_m_m_a_n_d _e_n_v_i_r_o_n_m_e_n_t section for details on how the environment
list is constructed.
PPrroocceessss mmooddeell
If ssuuddoo has been configured with PAM support or if I/O logging is
enabled, ssuuddoo must wait until the command has completed before it will
exit. In the case of PAM, ssuuddoo must remain running so that it can close
the PAM session when the command is finished. If neither PAM nor I/O
logging are configured, ssuuddoo will execute the command without calling
fork(2). In either case, ssuuddoo sets up the execution environment as
described above, and calls the execve system call (potentially in a child
process). If I/O logging is enabled, a new pseudo-terminal (``pty'') is
created and a second ssuuddoo 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.
SSiiggnnaall hhaannddlliinngg
If the command is run as a child of the ssuuddoo process (due to PAM or I/O
logging), ssuuddoo 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 ssuuddoo.
As a special case, ssuuddoo 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 systyem.
This prevents ssuuddoo 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 ssuuddoo and not
any other processes that the command may create. As a result, running a
script that calls reboot(1m) or shutdown(1m) via ssuuddoo may cause the system
to end up in this undefined state unless the reboot(1m) or shutdown(1m) are
run using the eexxeecc() family of functions instead of ssyysstteemm() (which
interposes a shell between the command and the calling process).
EEXXIITT VVAALLUUEE
Upon successful execution of a program, the exit status from _s_u_d_o 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 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.
LLOOGG FFOORRMMAATT
ssuuddoo can log events using either syslog(3) or a simple log file. In each
case the log format is almost identical.
AAcccceepptteedd ccoommmmaanndd lloogg eennttrriieess
Commands that sudo runs are logged using the following format (split into
multiple lines for readability):
date hostname progname: username : TTY=ttyname ; PWD=cwd ; \
USER=runasuser ; GROUP=runasgroup ; TSID=logid ; \
ENV=env_vars COMMAND=command
Where the fields are as follows:
date The date the command was run. Typically, this is in the
format ``MMM, DD, HH:MM:SS''. If logging via syslog(3),
the actual date format is controlled by the syslog daemon.
If logging to a file and the _l_o_g___y_e_a_r option is enabled,
the date will also include the year.
hostname The name of the host ssuuddoo was run on. This field is only
present when logging via syslog(3).
progname The name of the program, usually _s_u_d_o or _s_u_d_o_e_d_i_t. This
field is only present when logging via syslog(3).
username The login name of the user who ran ssuuddoo.
ttyname The short name of the terminal (e.g. ``console'',
``tty01'', or ``pts/0'') ssuuddoo was run on, or ``unknown'' if
there was no terminal present.
cwd The current working directory that ssuuddoo was run in.
runasuser The user the command was run as.
runasgroup The group the command was run as if one was specified on
the command line.
logid An I/O log identifier that can be used to replay the
command's output. This is only present when the _l_o_g___i_n_p_u_t
or _l_o_g___o_u_t_p_u_t option is enabled.
env_vars A list of environment variables specified on the command
line, if specified.
command The actual command that was executed.
Messages are logged using the locale specified by _s_u_d_o_e_r_s___l_o_c_a_l_e, which
defaults to the ``C'' locale.
DDeenniieedd ccoommmmaanndd lloogg eennttrriieess
If the user is not allowed to run the command, the reason for the denial
will follow the user name. Possible reasons include:
user NOT in sudoers
The user is not listed in the _s_u_d_o_e_r_s file.
user NOT authorized on host
The user is listed in the _s_u_d_o_e_r_s file but is not allowed to run
commands on the host.
command not allowed
The user is listed in the _s_u_d_o_e_r_s file for the host but they are not
allowed to run the specified command.
3 incorrect password attempts
The user failed to enter their password after 3 tries. The actual
number of tries will vary based on the number of failed attempts and
the value of the _p_a_s_s_w_d___t_r_i_e_s _s_u_d_o_e_r_s option.
a password is required
The --nn option was specified but a password was required.
sorry, you are not allowed to set the following environment variables
The user specified environment variables on the command line that were
not allowed by _s_u_d_o_e_r_s.
EErrrroorr lloogg eennttrriieess
If an error occurs, ssuuddoo will log a message and, in most cases, send a
message to the administrator via email. Possible errors include:
parse error in /etc/sudoers near line N
ssuuddoo encountered an error when parsing the specified file. In some
cases, the actual error may be one line above or below the line number
listed, depending on the type of error.
problem with defaults entries
The _s_u_d_o_e_r_s file contains one or more unknown Defaults settings. This
does not prevent ssuuddoo from running, but the _s_u_d_o_e_r_s file should be
checked using vviissuuddoo.
timestamp owner (username): No such user
The time stamp directory owner, as specified by the _t_i_m_e_s_t_a_m_p_o_w_n_e_r
setting, could not be found in the password database.
unable to open/read /etc/sudoers
The _s_u_d_o_e_r_s file could not be opened for reading. This can happen
when the _s_u_d_o_e_r_s file is located on a remote file system that maps
user ID 0 to a different value. Normally, ssuuddoo tries to open _s_u_d_o_e_r_s
using group permissions to avoid this problem.
unable to stat /etc/sudoers
The _/_e_t_c_/_s_u_d_o_e_r_s file is missing.
/etc/sudoers is not a regular file
The _/_e_t_c_/_s_u_d_o_e_r_s file exists but is not a regular file or symbolic
link.
/etc/sudoers is owned by uid N, should be 0
The _s_u_d_o_e_r_s file has the wrong owner.
/etc/sudoers is world writable
The permissions on the _s_u_d_o_e_r_s file allow all users to write to it.
The _s_u_d_o_e_r_s file must not be world-writable, the default file mode is
0440 (readable by owner and group, writable by none).
/etc/sudoers is owned by gid N, should be 1
The _s_u_d_o_e_r_s file has the wrong group ownership.
unable to open /var/adm/sudo/username/ttyname
_s_u_d_o_e_r_s was unable to read or create the user's time stamp file.
unable to write to /var/adm/sudo/username/ttyname
_s_u_d_o_e_r_s was unable to write to the user's time stamp file.
unable to mkdir to /var/adm/sudo/username
_s_u_d_o_e_r_s was unable to create the user's time stamp directory.
NNootteess oonn llooggggiinngg vviiaa ssyysslloogg
By default, _s_u_d_o_e_r_s logs messages via syslog(3). The _d_a_t_e, _h_o_s_t_n_a_m_e, and
_p_r_o_g_n_a_m_e fields are added by the syslog daemon, not _s_u_d_o_e_r_s itself. As
such, they may vary in format on different systems.
On most systems, syslog(3) has a relatively small log buffer. To prevent
the command line arguments from being truncated, ssuuddoo will split up log
messages that are larger than 960 characters (not including the date,
hostname, and the string ``sudo''). When a message is split, additional
parts will include the string ``(command continued)'' after the user name
and before the continued command line arguments.
NNootteess oonn llooggggiinngg ttoo aa ffiillee
If the _l_o_g_f_i_l_e option is set, _s_u_d_o_e_r_s will log to a local file, such as
_/_v_a_r_/_l_o_g_/_s_u_d_o. When logging to a file, _s_u_d_o_e_r_s uses a format similar to
syslog(3), with a few important differences:
1. The _p_r_o_g_n_a_m_e and _h_o_s_t_n_a_m_e fields are not present.
2. If the _l_o_g___y_e_a_r _s_u_d_o_e_r_s option is enabled, the date will also
include the year.
3. Lines that are longer than _l_o_g_l_i_n_e_l_e_n characters (80 by default) are
word-wrapped and continued on the next line with a four character
indent. This makes entries easier to read for a human being, but
makes it more difficult to use grep(1) on the log files. If the
_l_o_g_l_i_n_e_l_e_n _s_u_d_o_e_r_s option is set to 0 (or negated with a `!'), word
wrap will be disabled.
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.
ssuuddoo will check the ownership of its time stamp directory (_/_v_a_r_/_a_d_m_/_s_u_d_o
by default) and ignore the directory's contents if it is not owned by
root or if it is writable by a user other than root. On systems that
allow non-root users to give away files via chown(2), if the time stamp
directory is located in a world-writable directory (e.g., _/_t_m_p), it is
possible for a user to create the time stamp directory before ssuuddoo is
run. However, because ssuuddoo checks the ownership and mode of the
directory and its contents, the only damage that can be done is to
``hide'' files by putting them in the time stamp dir. This is unlikely
to happen since once the time stamp dir is owned by root and inaccessible
by any other user, the user placing files there would be unable to get
them back out.
ssuuddoo will not honor time stamps set far in the future. Time stamps with
a date greater than current_time + 2 * TIMEOUT will be ignored and sudo
will log and complain. This is done to keep a user from creating his/her
own time stamp with a bogus date on systems that allow users to give away
files if the time stamp directory is located in a world-writable
directory.
On systems where the boot time is available, ssuuddoo will ignore time stamps
that date from before the machine booted.
Since time stamp files live in the file system, they can outlive a user's
login session. As a result, a user may be able to login, run a command
with ssuuddoo after authenticating, logout, login again, and run ssuuddoo without
authenticating so long as the time stamp file's modification time is
within 5 minutes (or whatever the timeout is set to in _s_u_d_o_e_r_s). When
the _t_t_y___t_i_c_k_e_t_s _s_u_d_o_e_r_s option is enabled, the time stamp has per-tty
granularity but still may outlive the user's session. On Linux systems
where the devpts filesystem is used, Solaris systems with the devices
filesystem, as well as other systems that utilize a devfs filesystem that
monotonically increase the inode number of devices as they are created
(such as Mac OS X), ssuuddoo is able to determine when a tty-based time stamp
file is stale and will ignore it. Administrators should not rely on this
feature as it is not universally available.
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 _P_R_E_V_E_N_T_I_N_G _S_H_E_L_L _E_S_C_A_P_E_S section in
sudoers(4).
To prevent the disclosure of potentially sensitive information, ssuuddoo
disables core dumps by default while it is executing (they are re-enabled
for the command that is run).
For information on the security implications of _s_u_d_o_e_r_s entries, please
see the _S_E_C_U_R_I_T_Y _N_O_T_E_S section in sudoers(4).
EENNVVIIRROONNMMEENNTT
ssuuddoo utilizes the following environment variables:
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 Set to a sane value if the _s_e_c_u_r_e___p_a_t_h option is set in
the _s_u_d_o_e_r_s file.
SHELL Used to determine shell to run with --ss option.
SUDO_ASKPASS Specifies the path to a helper program used to read the
password if no terminal is available or if the --AA 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 name 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_e_r_s List of who can run what
_/_v_a_r_/_a_d_m_/_s_u_d_o Directory containing time stamps
_/_e_t_c_/_e_n_v_i_r_o_n_m_e_n_t Initial environment for --ii mode on AIX and
Linux systems
EEXXAAMMPPLLEESS
Note: the following examples assume suitable sudoers(4) entries.
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 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"
SSEEEE AALLSSOO
grep(1), su(1), stat(2), login_cap(3), passwd(4), sudoers(4),
sudoreplay(1m), visudo(1m)
HHIISSTTOORRYY
See the HISTORY file in the ssuuddoo distribution
(http://www.sudo.ws/sudo/history.html) for a brief history of sudo.
AAUUTTHHOORRSS
Many people have worked on ssuuddoo over the years; this version consists of
code written primarily by:
Todd C. Miller
See the CONTRIBUTORS file in the ssuuddoo distribution
(http://www.sudo.ws/sudo/contributors.html) for an exhaustive list of
people who have contributed to 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 ssuuddoo '' ss _n_o_e_x_e_c functionality. See the
sudoers(4) manual for details.
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 _E_X_A_M_P_L_E_S 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.
Sudo 1.7.10 July 10, 2012 Sudo 1.7.10