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