SUDOERS(4) File Formats Manual SUDOERS(4) NNAAMMEE ssuuddooeerrss - default sudo security policy plugin DDEESSCCRRIIPPTTIIOONN The ssuuddooeerrss policy plugin determines a user's ssuuddoo privileges. It is the default ssuuddoo policy plugin. The policy is driven by the _/_e_t_c_/_s_u_d_o_e_r_s file or, optionally in LDAP. The policy format is described in detail in the _S_U_D_O_E_R_S _F_I_L_E _F_O_R_M_A_T section. For information on storing ssuuddooeerrss policy information in LDAP, please see sudoers.ldap(4). CCoonnffiigguurriinngg ssuuddoo..ccoonnff ffoorr ssuuddooeerrss ssuuddoo consults the sudo.conf(4) file to determine which policy and and I/O logging plugins to load. If no sudo.conf(4) file is present, or if it contains no Plugin lines, ssuuddooeerrss will be used for policy decisions and I/O logging. To explicitly configure sudo.conf(4) to use the ssuuddooeerrss plugin, the following configuration can be used. Plugin sudoers_policy sudoers.so Plugin sudoers_io sudoers.so Starting with ssuuddoo 1.8.5, it is possible to specify optional arguments to the ssuuddooeerrss plugin in the sudo.conf(4) file. These arguments, if present, should be listed after the path to the plugin (i.e. after _s_u_d_o_e_r_s_._s_o). Multiple arguments may be specified, separated by white space. For example: Plugin sudoers_policy sudoers.so sudoers_mode=0400 The following plugin arguments are supported: ldap_conf=pathname The _l_d_a_p___c_o_n_f argument can be used to override the default path to the _l_d_a_p_._c_o_n_f file. ldap_secret=pathname The _l_d_a_p___s_e_c_r_e_t argument can be used to override the default path to the _l_d_a_p_._s_e_c_r_e_t file. sudoers_file=pathname The _s_u_d_o_e_r_s___f_i_l_e argument can be used to override the default path to the _s_u_d_o_e_r_s file. sudoers_uid=uid The _s_u_d_o_e_r_s___u_i_d argument can be used to override the default owner of the sudoers file. It should be specified as a numeric user ID. sudoers_gid=gid The _s_u_d_o_e_r_s___g_i_d argument can be used to override the default group of the sudoers file. It must be specified as a numeric group ID (not a group name). sudoers_mode=mode The _s_u_d_o_e_r_s___m_o_d_e argument can be used to override the default file mode for the sudoers file. It should be specified as an octal value. For more information on configuring sudo.conf(4), please refer to its manual. UUsseerr AAuutthheennttiiccaattiioonn The ssuuddooeerrss security policy requires that most users authenticate themselves before they can use ssuuddoo. 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 policy has disabled authentication for the user or command. Unlike su(1), when ssuuddooeerrss 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 flags, described later. If a user who is not listed in the policy 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 Defaults entry (described later) and defaults to root. Note that no mail will be sent if an unauthorized user tries to run ssuuddoo with the --ll or --vv option unless there is an authentication error and either the _m_a_i_l___a_l_w_a_y_s or _m_a_i_l___b_a_d_p_a_s_s flags are enabled. This allows users to determine for themselves whether or not they are allowed to use ssuuddoo. All attempts to run ssuuddoo (successful or not) will be logged, regardless of whether or not mail is sent. If ssuuddoo is run by root and the SUDO_USER environment variable is set, the ssuuddooeerrss policy will use this value to determine who the actual user is. This can be used by a user to log commands through sudo 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 file lookup is still done for root, not the user specified by SUDO_USER. ssuuddooeerrss uses per-user time stamp files for credential caching. Once a user has been authenticated, a record is written containing the uid that was used to authenticate, the terminal session ID, and a time stamp (using a monotonic clock if one is available). The user may then use ssuuddoo 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, ssuuddooeerrss uses a separate record for each tty, which means that a user's login sessions are authenticated separately. 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. LLooggggiinngg ssuuddooeerrss can log both successful and unsuccessful attempts (as well as errors) to syslog(3), a log file, or both. By default, ssuuddooeerrss 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. See _L_O_G _F_O_R_M_A_T for a description of the log file format. ssuuddooeerrss is also capable of running a command in a pseudo-tty and logging all input and/or output. The standard input, standard output and standard error can be logged even when not associated with a terminal. 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 options as well as the LOG_INPUT and LOG_OUTPUT command tags. See _I_/_O _L_O_G _F_I_L_E_S for details on how I/O log files are stored. CCoommmmaanndd eennvviirroonnmmeenntt Since environment variables can influence program behavior, ssuuddooeerrss 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 ssuuddooeerrss can deal 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. Environment variables with a value beginning with () are removed unless both the name and value parts are matched by _e_n_v___k_e_e_p or _e_n_v___c_h_e_c_k, as they will be interpreted as functions by older versions of the bbaasshh shell. Prior to version 1.8.11, such variables were always removed. 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. Environment variables with a value beginning with () are always removed, even if they do not match one of the blacklists. 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. By default, environment variables are matched by name. However, if the pattern includes an equal sign (`='), both the variables name and value must match. For example, an old-style (pre-shellshock) bbaasshh shell function could be matched as follows: env_keep += "my_func=()*" Without the ``=()*'' suffix, this would not match, as old-style bbaasshh shell functions are not preserved by default. The complete list of environment variables that ssuuddoo allows or denies is contained in the output of ``sudo -V'' when run as root. Please note that this list varies based on the operating system ssuuddoo is running on. On systems that support PAM where the ppaamm__eennvv module is enabled for ssuuddoo, variables in the PAM environment may be merged in to the environment. If a variable in the PAM environment is already present in the user's environment, the value will only be overridden if the variable was not preserved by ssuuddooeerrss. When _e_n_v___r_e_s_e_t is enabled, variables preserved from the invoking user's environment by the _e_n_v___k_e_e_p list take precedence over those in the PAM environment. When _e_n_v___r_e_s_e_t is disabled, variables present the invoking user's environment take precedence over those in the PAM environment unless they match a pattern in the _e_n_v___d_e_l_e_t_e list. 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, ssuuddooeerrss 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 flag 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. SSUUDDOOEERRSS FFIILLEE FFOORRMMAATT The _s_u_d_o_e_r_s file is composed of two types of entries: aliases (basically variables) and user specifications (which specify who may run what). When multiple entries match for a user, they are applied in order. Where there are multiple matches, the last match is used (which is not necessarily the most specific match). The _s_u_d_o_e_r_s file grammar will be described below in Extended Backus-Naur Form (EBNF). Don't despair if you are unfamiliar with EBNF; it is fairly simple, and the definitions below are annotated. QQuuiicckk gguuiiddee ttoo EEBBNNFF EBNF is a concise and exact way of describing the grammar of a language. Each EBNF definition is made up of _p_r_o_d_u_c_t_i_o_n _r_u_l_e_s. E.g., symbol ::= definition | alternate1 | alternate2 ... Each _p_r_o_d_u_c_t_i_o_n _r_u_l_e references others and thus makes up a grammar for the language. EBNF also contains the following operators, which many readers will recognize from regular expressions. Do not, however, confuse them with ``wildcard'' characters, which have different meanings. ? Means that the preceding symbol (or group of symbols) is optional. That is, it may appear once or not at all. * Means that the preceding symbol (or group of symbols) may appear zero or more times. + Means that the preceding symbol (or group of symbols) may appear one or more times. Parentheses may be used to group symbols together. For clarity, we will use single quotes ('') to designate what is a verbatim character string (as opposed to a symbol name). AAlliiaasseess There are four kinds of aliases: User_Alias, Runas_Alias, Host_Alias and Cmnd_Alias. Alias ::= 'User_Alias' User_Alias (':' User_Alias)* | 'Runas_Alias' Runas_Alias (':' Runas_Alias)* | 'Host_Alias' Host_Alias (':' Host_Alias)* | 'Cmnd_Alias' Cmnd_Alias (':' Cmnd_Alias)* User_Alias ::= NAME '=' User_List Runas_Alias ::= NAME '=' Runas_List Host_Alias ::= NAME '=' Host_List Cmnd_Alias ::= NAME '=' Cmnd_List NAME ::= [A-Z]([A-Z][0-9]_)* Each _a_l_i_a_s definition is of the form Alias_Type NAME = item1, item2, ... where _A_l_i_a_s___T_y_p_e is one of User_Alias, Runas_Alias, Host_Alias, or Cmnd_Alias. A NAME is a string of uppercase letters, numbers, and underscore characters (`_'). A NAME mmuusstt start with an uppercase letter. It is possible to put several alias definitions of the same type on a single line, joined by a colon (`:'). E.g., Alias_Type NAME = item1, item2, item3 : NAME = item4, item5 It is a syntax error to redefine an existing _a_l_i_a_s. It is possible to use the same name for _a_l_i_a_s_e_s of different types, but this is not recommended. The definitions of what constitutes a valid _a_l_i_a_s member follow. User_List ::= User | User ',' User_List User ::= '!'* user name | '!'* #uid | '!'* %group | '!'* %#gid | '!'* +netgroup | '!'* %:nonunix_group | '!'* %:#nonunix_gid | '!'* User_Alias A User_List is made up of one or more user names, user IDs (prefixed with `#'), system group names and IDs (prefixed with `%' and `%#' respectively), netgroups (prefixed with `+'), non-Unix group names and IDs (prefixed with `%:' and `%:#' respectively) and User_Aliases. Each list item may be prefixed with zero or more `!' operators. An odd number of `!' operators negate the value of the item; an even number just cancel each other out. User netgroups are matched using the user and domain members only; the host member is not used when matching. A user name, uid, group, gid, netgroup, nonunix_group or nonunix_gid may be enclosed in double quotes to avoid the need for escaping special characters. Alternately, special characters may be specified in escaped hex mode, e.g. \x20 for space. When using double quotes, any prefix characters must be included inside the quotes. The actual nonunix_group and nonunix_gid syntax depends on the underlying group provider plugin. For instance, the QAS AD plugin supports the following formats: ++oo Group in the same domain: "%:Group Name" ++oo Group in any domain: "%:Group Name@FULLY.QUALIFIED.DOMAIN" ++oo Group SID: "%:S-1-2-34-5678901234-5678901234-5678901234-567" See _G_R_O_U_P _P_R_O_V_I_D_E_R _P_L_U_G_I_N_S for more information. Note that quotes around group names are optional. Unquoted strings must use a backslash (`\') to escape spaces and special characters. See _O_t_h_e_r _s_p_e_c_i_a_l _c_h_a_r_a_c_t_e_r_s _a_n_d _r_e_s_e_r_v_e_d _w_o_r_d_s for a list of characters that need to be escaped. Runas_List ::= Runas_Member | Runas_Member ',' Runas_List Runas_Member ::= '!'* user name | '!'* #uid | '!'* %group | '!'* %#gid | '!'* %:nonunix_group | '!'* %:#nonunix_gid | '!'* +netgroup | '!'* Runas_Alias A Runas_List is similar to a User_List except that instead of User_Aliases it can contain Runas_Aliases. Note that user names and groups are matched as strings. In other words, two users (groups) with the same uid (gid) are considered to be distinct. If you wish to match all user names with the same uid (e.g. root and toor), you can use a uid instead (#0 in the example given). Host_List ::= Host | Host ',' Host_List Host ::= '!'* host name | '!'* ip_addr | '!'* network(/netmask)? | '!'* +netgroup | '!'* Host_Alias A Host_List is made up of one or more host names, IP addresses, network numbers, netgroups (prefixed with `+') and other aliases. Again, the value of an item may be negated with the `!' operator. Host netgroups are matched using the host (both qualified and unqualified) and domain members only; the user member is not used when matching. If you specify a network number without a netmask, ssuuddoo will query each of the local host's network interfaces and, if the network number corresponds to one of the hosts's network interfaces, will use the netmask of that interface. The netmask may be specified either in standard IP address notation (e.g. 255.255.255.0 or ffff:ffff:ffff:ffff::), or CIDR notation (number of bits, e.g. 24 or 64). A host name may include shell-style wildcards (see the _W_i_l_d_c_a_r_d_s section below), but unless the host name command on your machine returns the fully qualified host name, you'll need to use the _f_q_d_n option for wildcards to be useful. Note that ssuuddoo only inspects actual network interfaces; this means that IP address 127.0.0.1 (localhost) will never match. Also, the host name ``localhost'' will only match if that is the actual host name, which is usually only the case for non-networked systems. digest ::= [A-Fa-f0-9]+ | [[A-Za-z0-9+/=]+ Digest_Spec ::= "sha224" ':' digest | "sha256" ':' digest | "sha384" ':' digest | "sha512" ':' digest Cmnd_List ::= Cmnd | Cmnd ',' Cmnd_List command name ::= file name | file name args | file name '""' Cmnd ::= Digest_Spec? '!'* command name | '!'* directory | '!'* "sudoedit" | '!'* Cmnd_Alias A Cmnd_List is a list of one or more command names, directories, and other aliases. A command name is a fully qualified file name which may include shell-style wildcards (see the _W_i_l_d_c_a_r_d_s section below). A simple file name allows the user to run the command with any arguments he/she wishes. However, you may also specify command line arguments (including wildcards). Alternately, you can specify "" to indicate that the command may only be run wwiitthhoouutt command line arguments. A directory is a fully qualified path name ending in a `/'. When you specify a directory in a Cmnd_List, the user will be able to run any file within that directory (but not in any sub-directories therein). If a Cmnd has associated command line arguments, then the arguments in the Cmnd must match exactly those given by the user on the command line (or match the wildcards if there are any). Note that the following characters must be escaped with a `\' if they are used in command arguments: `,', `:', `=', `\'. The built-in command ``sudoedit'' is used to permit a user to run ssuuddoo with the --ee option (or as ssuuddooeeddiitt). It may take command line arguments just as a normal command does. Note that ``sudoedit'' is a command built into ssuuddoo itself and must be specified in the _s_u_d_o_e_r_s file without a leading path. If a command name is prefixed with a Digest_Spec, the command will only match successfully if it can be verified using the specified SHA-2 digest. The following digest formats are supported: sha224, sha256, sha384 and sha512. The string may be specified in either hex or base64 format (base64 is more compact). There are several utilities capable of generating SHA-2 digests in hex format such as openssl, shasum, sha224sum, sha256sum, sha384sum, sha512sum. For example, using openssl: $ openssl dgst -sha224 /bin/ls SHA224(/bin/ls)= 118187da8364d490b4a7debbf483004e8f3e053ec954309de2c41a25 It is also possible to use openssl to generate base64 output: $ openssl dgst -binary -sha224 /bin/ls | openssl base64 EYGH2oNk1JC0p9679IMATo8+BT7JVDCd4sQaJQ== Warning, if the user has write access to the command itself (directly or via a ssuuddoo command), it may be possible for the user to replace the command after the digest check has been performed but before the command is executed. A similar race condition exists on systems that lack the fexecve(2) system call when the directory in which the command is located is writable by the user. Command digests are only supported by version 1.8.7 or higher. DDeeffaauullttss Certain configuration options may be changed from their default values at run-time via one or more Default_Entry lines. These may affect all users on any host, all users on a specific host, a specific user, a specific command, or commands being run as a specific user. Note that per-command entries may not include command line arguments. If you need to specify arguments, define a Cmnd_Alias and reference that instead. Default_Type ::= 'Defaults' | 'Defaults' '@' Host_List | 'Defaults' ':' User_List | 'Defaults' '!' Cmnd_List | 'Defaults' '>' Runas_List Default_Entry ::= Default_Type Parameter_List Parameter_List ::= Parameter | Parameter ',' Parameter_List Parameter ::= Parameter '=' Value | Parameter '+=' Value | Parameter '-=' Value | '!'* Parameter Parameters may be ffllaaggss, iinntteeggeerr values, ssttrriinnggss, or lliissttss. Flags are implicitly boolean and can be turned off via the `!' operator. Some integer, string and list parameters may also be used in a boolean context to disable them. Values may be enclosed in double quotes ("") when they contain multiple words. Special characters may be escaped with a backslash (`\'). Lists have two additional assignment operators, += and -=. These operators are used to add to and delete from a list respectively. It is not an error to use the -= operator to remove an element that does not exist in a list. Defaults entries are parsed in the following order: generic, host and user Defaults first, then runas Defaults and finally command defaults. See _S_U_D_O_E_R_S _O_P_T_I_O_N_S for a list of supported Defaults parameters. UUsseerr ssppeecciiffiiccaattiioonn User_Spec ::= User_List Host_List '=' Cmnd_Spec_List \ (':' Host_List '=' Cmnd_Spec_List)* Cmnd_Spec_List ::= Cmnd_Spec | Cmnd_Spec ',' Cmnd_Spec_List Cmnd_Spec ::= Runas_Spec? SELinux_Spec? Solaris_Priv_Spec? Tag_Spec* Cmnd Runas_Spec ::= '(' Runas_List? (':' Runas_List)? ')' SELinux_Spec ::= ('ROLE=role' | 'TYPE=type') Solaris_Priv_Spec ::= ('PRIVS=privset' | 'LIMITPRIVS=privset') Tag_Spec ::= ('EXEC:' | 'NOEXEC:' | 'FOLLOW:' | 'NOFOLLOW' | 'LOG_INPUT:' | 'NOLOG_INPUT:' | 'LOG_OUTPUT:' | 'NOLOG_OUTPUT:' | 'MAIL:' | 'NOMAIL:' | 'PASSWD:' | 'NOPASSWD:' | 'SETENV:' | 'NOSETENV:') A uusseerr ssppeecciiffiiccaattiioonn determines which commands a user may run (and as what user) on specified hosts. By default, commands are run as rroooott, but this can be changed on a per-command basis. The basic structure of a user specification is ``who where = (as_whom) what''. Let's break that down into its constituent parts: RRuunnaass__SSppeecc A Runas_Spec determines the user and/or the group that a command may be run as. A fully-specified Runas_Spec consists of two Runas_Lists (as defined above) separated by a colon (`:') and enclosed in a set of parentheses. The first Runas_List indicates which users the command may be run as via ssuuddoo's --uu option. The second defines a list of groups that can be specified via ssuuddoo's --gg option. If both Runas_Lists are specified, the command may be run with any combination of users and groups listed in their respective Runas_Lists. If only the first is specified, the command may be run as any user in the list but no --gg option may be specified. If the first Runas_List is empty but the second is specified, the command may be run as the invoking user with the group set to any listed in the Runas_List. If both Runas_Lists are empty, the command may only be run as the invoking user. If no Runas_Spec is specified the command may be run as rroooott and no group may be specified. A Runas_Spec sets the default for the commands that follow it. What this means is that for the entry: dgb boulder = (operator) /bin/ls, /bin/kill, /usr/bin/lprm The user ddggbb may run _/_b_i_n_/_l_s, _/_b_i_n_/_k_i_l_l, and _/_u_s_r_/_b_i_n_/_l_p_r_m--but only as ooppeerraattoorr. E.g., $ sudo -u operator /bin/ls It is also possible to override a Runas_Spec later on in an entry. If we modify the entry like so: dgb boulder = (operator) /bin/ls, (root) /bin/kill, /usr/bin/lprm Then user ddggbb is now allowed to run _/_b_i_n_/_l_s as ooppeerraattoorr, but _/_b_i_n_/_k_i_l_l and _/_u_s_r_/_b_i_n_/_l_p_r_m as rroooott. We can extend this to allow ddggbb to run /bin/ls with either the user or group set to ooppeerraattoorr: dgb boulder = (operator : operator) /bin/ls, (root) /bin/kill,\ /usr/bin/lprm Note that while the group portion of the Runas_Spec permits the user to run as command with that group, it does not force the user to do so. If no group is specified on the command line, the command will run with the group listed in the target user's password database entry. The following would all be permitted by the sudoers entry above: $ sudo -u operator /bin/ls $ sudo -u operator -g operator /bin/ls $ sudo -g operator /bin/ls In the following example, user ttccmm may run commands that access a modem device file with the dialer group. tcm boulder = (:dialer) /usr/bin/tip, /usr/bin/cu,\ /usr/local/bin/minicom Note that in this example only the group will be set, the command still runs as user ttccmm. E.g. $ sudo -g dialer /usr/bin/cu Multiple users and groups may be present in a Runas_Spec, in which case the user may select any combination of users and groups via the --uu and --gg options. In this example: alan ALL = (root, bin : operator, system) ALL user aallaann may run any command as either user root or bin, optionally setting the group to operator or system. SSEELLiinnuuxx__SSppeecc On systems with SELinux support, _s_u_d_o_e_r_s file entries may optionally have an SELinux role and/or type associated with a command. If a role or type is specified with the command it will override any default values specified in _s_u_d_o_e_r_s. A role or type specified on the command line, however, will supersede the values in _s_u_d_o_e_r_s. SSoollaarriiss__PPrriivv__SSppeecc On Solaris systems, _s_u_d_o_e_r_s file entries may optionally specify Solaris privilege set and/or limit privilege set associated with a command. If privileges or limit privileges are specified with the command it will override any default values specified in _s_u_d_o_e_r_s. A privilege set is a comma-separated list of privilege names. The ppriv(1) command can be used to list all privileges known to the system. For example: $ ppriv -l In addition, there are several ``special'' privilege strings: none the empty set all the set of all privileges zone the set of all privileges available in the current zone basic the default set of privileges normal users are granted at login time Privileges can be excluded from a set by prefixing the privilege name with either an `!' or `-' character. TTaagg__SSppeecc A command may have zero or more tags associated with it. There are ten possible tag values: EXEC, NOEXEC, FOLLOW, NOFOLLOW, LOG_INPUT, NOLOG_INPUT, LOG_OUTPUT, NOLOG_OUTPUT, MAIL, NOMAIL, PASSWD, NOPASSWD, SETENV, and NOSETENV. Once a tag is set on a Cmnd, subsequent Cmnds in the Cmnd_Spec_List, inherit the tag unless it is overridden by the opposite tag (in other words, PASSWD overrides NOPASSWD and NOEXEC overrides EXEC). _E_X_E_C and _N_O_E_X_E_C If ssuuddoo has been compiled with _n_o_e_x_e_c support and the underlying operating system supports it, the NOEXEC tag can be used to prevent a dynamically-linked executable from running further commands itself. In the following example, user aaaarroonn may run _/_u_s_r_/_b_i_n_/_m_o_r_e and _/_u_s_r_/_b_i_n_/_v_i but shell escapes will be disabled. aaron shanty = NOEXEC: /usr/bin/more, /usr/bin/vi 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 below for more details on how NOEXEC works and whether or not it will work on your system. _F_O_L_L_O_W and _N_O_F_O_L_L_O_W Starting with version 1.8.15, ssuuddooeeddiitt will not open a file that is a symbolic link unless the _s_u_d_o_e_d_i_t___f_o_l_l_o_w option is enabled. The _F_O_L_L_O_W and _N_O_F_O_L_L_O_W tags override the value of _s_u_d_o_e_d_i_t___f_o_l_l_o_w and can be used to permit (or deny) the editing of symbolic links on a per-command basis. These tags are only effective for the _s_u_d_o_e_d_i_t command and are ignored for all other commands. _L_O_G___I_N_P_U_T and _N_O_L_O_G___I_N_P_U_T These tags override the value of the _l_o_g___i_n_p_u_t option on a per-command basis. For more information, see the description of _l_o_g___i_n_p_u_t in the _S_U_D_O_E_R_S _O_P_T_I_O_N_S section below. _L_O_G___O_U_T_P_U_T and _N_O_L_O_G___O_U_T_P_U_T These tags override the value of the _l_o_g___o_u_t_p_u_t option on a per-command basis. For more information, see the description of _l_o_g___o_u_t_p_u_t in the _S_U_D_O_E_R_S _O_P_T_I_O_N_S section below. _M_A_I_L and _N_O_M_A_I_L These tags provide fine-grained control over whether mail will be sent when a user runs a command by overriding the value of the _m_a_i_l___a_l_l___c_m_n_d_s option on a per-command basis. They have no effect when ssuuddoo is run with the --ll or --vv options. A _N_O_M_A_I_L tag will also override the _m_a_i_l___a_l_w_a_y_s and _m_a_i_l___n_o___p_e_r_m_s options. For more information, see the descriptions of _m_a_i_l___a_l_l___c_m_n_d_s, _m_a_i_l___a_l_w_a_y_s, and _m_a_i_l___n_o___p_e_r_m_s in the _S_U_D_O_E_R_S _O_P_T_I_O_N_S section below. _P_A_S_S_W_D and _N_O_P_A_S_S_W_D By default, ssuuddoo requires that a user authenticate him or herself before running a command. This behavior can be modified via the NOPASSWD tag. Like a Runas_Spec, the NOPASSWD tag sets a default for the commands that follow it in the Cmnd_Spec_List. Conversely, the PASSWD tag can be used to reverse things. For example: ray rushmore = NOPASSWD: /bin/kill, /bin/ls, /usr/bin/lprm would allow the user rraayy to run _/_b_i_n_/_k_i_l_l, _/_b_i_n_/_l_s, and _/_u_s_r_/_b_i_n_/_l_p_r_m as rroooott on the machine rushmore without authenticating himself. If we only want rraayy to be able to run _/_b_i_n_/_k_i_l_l without a password the entry would be: ray rushmore = NOPASSWD: /bin/kill, PASSWD: /bin/ls, /usr/bin/lprm Note, however, that the PASSWD tag has no effect on users who are in the group specified by the _e_x_e_m_p_t___g_r_o_u_p option. By default, if the NOPASSWD tag is applied to any of the entries for a user on the current host, he or she will be able to run ``sudo -l'' without a password. Additionally, a user may only run ``sudo -v'' without a password if the NOPASSWD tag is present for all a user's entries that pertain to the current host. This behavior may be overridden via the _v_e_r_i_f_y_p_w and _l_i_s_t_p_w options. _S_E_T_E_N_V and _N_O_S_E_T_E_N_V These tags override the value of the _s_e_t_e_n_v option on a per-command basis. Note that if SETENV has been set for a command, the user may disable the _e_n_v___r_e_s_e_t option from the command line via the --EE option. Additionally, environment variables set on the command line are not subject to the restrictions imposed by _e_n_v___c_h_e_c_k, _e_n_v___d_e_l_e_t_e, or _e_n_v___k_e_e_p. As such, only trusted users should be allowed to set variables in this manner. If the command matched is AALLLL, the SETENV tag is implied for that command; this default may be overridden by use of the NOSETENV tag. WWiillddccaarrddss ssuuddoo allows shell-style _w_i_l_d_c_a_r_d_s (aka meta or glob characters) to be used in host names, path names and command line arguments in the _s_u_d_o_e_r_s file. Wildcard matching is done via the glob(3) and fnmatch(3) functions as specified by IEEE Std 1003.1 (``POSIX.1''). * Matches any set of zero or more characters (including white space). ? Matches any single character (including white space). [...] Matches any character in the specified range. [!...] Matches any character _n_o_t in the specified range. \x For any character `x', evaluates to `x'. This is used to escape special characters such as: `*', `?', `[', and `]'. NNoottee tthhaatt tthheessee aarree nnoott rreegguullaarr eexxpprreessssiioonnss.. Unlike a regular expression there is no way to match one or more characters within a range. Character classes may be used if your system's glob(3) and fnmatch(3) functions support them. However, because the `:' character has special meaning in _s_u_d_o_e_r_s, it must be escaped. For example: /bin/ls [[\:alpha\:]]* Would match any file name beginning with a letter. Note that a forward slash (`/') will _n_o_t be matched by wildcards used in the file name portion of the command. This is to make a path like: /usr/bin/* match _/_u_s_r_/_b_i_n_/_w_h_o but not _/_u_s_r_/_b_i_n_/_X_1_1_/_x_t_e_r_m. When matching the command line arguments, however, a slash _d_o_e_s get matched by wildcards since command line arguments may contain arbitrary strings and not just path names. WWiillddccaarrddss iinn ccoommmmaanndd lliinnee aarrgguummeennttss sshhoouulldd bbee uusseedd wwiitthh ccaarree.. Command line arguments are matched as a single, concatenated string. This mean a wildcard character such as `?' or `*' will match across word boundaries, which may be unexpected. For example, while a sudoers entry like: %operator ALL = /bin/cat /var/log/messages* will allow command like: $ sudo cat /var/log/messages.1 It will also allow: $ sudo cat /var/log/messages /etc/shadow which is probably not what was intended. In most cases it is better to do command line processing outside of the _s_u_d_o_e_r_s file in a scripting language. EExxcceeppttiioonnss ttoo wwiillddccaarrdd rruulleess The following exceptions apply to the above rules: "" If the empty string "" is the only command line argument in the _s_u_d_o_e_r_s file entry it means that command is not allowed to be run with _a_n_y arguments. sudoedit Command line arguments to the _s_u_d_o_e_d_i_t built-in command should always be path names, so a forward slash (`/') will not be matched by a wildcard. IInncclluuddiinngg ootthheerr ffiilleess ffrroomm wwiitthhiinn ssuuddooeerrss It is possible to include other _s_u_d_o_e_r_s files from within the _s_u_d_o_e_r_s file currently being parsed using the #include and #includedir directives. This can be used, for example, to keep a site-wide _s_u_d_o_e_r_s file in addition to a local, per-machine file. For the sake of this example the site-wide _s_u_d_o_e_r_s file will be _/_e_t_c_/_s_u_d_o_e_r_s and the per-machine one will be _/_e_t_c_/_s_u_d_o_e_r_s_._l_o_c_a_l. To include _/_e_t_c_/_s_u_d_o_e_r_s_._l_o_c_a_l from within _/_e_t_c_/_s_u_d_o_e_r_s we would use the following line in _/_e_t_c_/_s_u_d_o_e_r_s: #include /etc/sudoers.local When ssuuddoo reaches this line it will suspend processing of the current file (_/_e_t_c_/_s_u_d_o_e_r_s) and switch to _/_e_t_c_/_s_u_d_o_e_r_s_._l_o_c_a_l. Upon reaching the end of _/_e_t_c_/_s_u_d_o_e_r_s_._l_o_c_a_l, the rest of _/_e_t_c_/_s_u_d_o_e_r_s will be processed. Files that are included may themselves include other files. A hard limit of 128 nested include files is enforced to prevent include file loops. If the path to the include file is not fully-qualified (does not begin with a `/', it must be located in the same directory as the sudoers file it was included from. For example, if _/_e_t_c_/_s_u_d_o_e_r_s contains the line: #include sudoers.local the file that will be included is _/_e_t_c_/_s_u_d_o_e_r_s_._l_o_c_a_l. The file name may also include the %h escape, signifying the short form of the host name. In other words, if the machine's host name is ``xerxes'', then #include /etc/sudoers.%h will cause ssuuddoo to include the file _/_e_t_c_/_s_u_d_o_e_r_s_._x_e_r_x_e_s. The #includedir directive can be used to create a _s_u_d_o_e_r_s_._d directory that the system package manager can drop _s_u_d_o_e_r_s file rules into as part of package installation. For example, given: #includedir /etc/sudoers.d ssuuddoo will read each file in _/_e_t_c_/_s_u_d_o_e_r_s_._d, skipping file names that end in `~' or contain a `.' character to avoid causing problems with package manager or editor temporary/backup files. Files are parsed in sorted lexical order. That is, _/_e_t_c_/_s_u_d_o_e_r_s_._d_/_0_1___f_i_r_s_t will be parsed before _/_e_t_c_/_s_u_d_o_e_r_s_._d_/_1_0___s_e_c_o_n_d. Be aware that because the sorting is lexical, not numeric, _/_e_t_c_/_s_u_d_o_e_r_s_._d_/_1___w_h_o_o_p_s would be loaded _a_f_t_e_r _/_e_t_c_/_s_u_d_o_e_r_s_._d_/_1_0___s_e_c_o_n_d. Using a consistent number of leading zeroes in the file names can be used to avoid such problems. Note that unlike files included via #include, vviissuuddoo will not edit the files in a #includedir directory unless one of them contains a syntax error. It is still possible to run vviissuuddoo with the --ff flag to edit the files directly, but this will not catch the redefinition of an _a_l_i_a_s that is also present in a different file. OOtthheerr ssppeecciiaall cchhaarraacctteerrss aanndd rreesseerrvveedd wwoorrddss The pound sign (`#') is used to indicate a comment (unless it is part of a #include directive or unless it occurs in the context of a user name and is followed by one or more digits, in which case it is treated as a uid). Both the comment character and any text after it, up to the end of the line, are ignored. The reserved word AALLLL is a built-in _a_l_i_a_s that always causes a match to succeed. It can be used wherever one might otherwise use a Cmnd_Alias, User_Alias, Runas_Alias, or Host_Alias. You should not try to define your own _a_l_i_a_s called AALLLL as the built-in alias will be used in preference to your own. Please note that using AALLLL can be dangerous since in a command context, it allows the user to run _a_n_y command on the system. An exclamation point (`!') can be used as a logical _n_o_t operator in a list or _a_l_i_a_s as well as in front of a Cmnd. This allows one to exclude certain values. For the `!' operator to be effective, there must be something for it to exclude. For example, to match all users except for root one would use: ALL,!root If the AALLLL, is omitted, as in: !root it would explicitly deny root but not match any other users. This is different from a true ``negation'' operator. Note, however, that using a `!' in conjunction with the built-in AALLLL alias to allow a user to run ``all but a few'' commands rarely works as intended (see _S_E_C_U_R_I_T_Y _N_O_T_E_S below). Long lines can be continued with a backslash (`\') as the last character on the line. White space between elements in a list as well as special syntactic characters in a _U_s_e_r _S_p_e_c_i_f_i_c_a_t_i_o_n (`=', `:', `(', `)') is optional. The following characters must be escaped with a backslash (`\') when used as part of a word (e.g. a user name or host name): `!', `=', `:', `,', `(', `)', `\'. SSUUDDOOEERRSS OOPPTTIIOONNSS ssuuddoo's behavior can be modified by Default_Entry lines, as explained earlier. A list of all supported Defaults parameters, grouped by type, are listed below. BBoooolleeaann FFllaaggss: always_query_group_plugin If a _g_r_o_u_p___p_l_u_g_i_n is configured, use it to resolve groups of the form %group as long as there is not also a system group of the same name. Normally, only groups of the form %:group are passed to the _g_r_o_u_p___p_l_u_g_i_n. This flag is _o_f_f by default. always_set_home If enabled, ssuuddoo will set the HOME environment variable to the home directory of the target user (which is root unless the --uu option is used). This effectively means that the --HH option is always implied. Note that by default, HOME will be set to the home directory of the target user when the _e_n_v___r_e_s_e_t option is enabled, so _a_l_w_a_y_s___s_e_t___h_o_m_e only has an effect for configurations where either _e_n_v___r_e_s_e_t is disabled or HOME is present in the _e_n_v___k_e_e_p list. This flag is _o_f_f by default. authenticate If set, users must authenticate themselves via a password (or other means of authentication) before they may run commands. This default may be overridden via the PASSWD and NOPASSWD tags. This flag is _o_n by default. closefrom_override If set, the user may use ssuuddoo's --CC option which overrides the default starting point at which ssuuddoo begins closing open file descriptors. This flag is _o_f_f by default. compress_io If set, and ssuuddoo is configured to log a command's input or output, the I/O logs will be compressed using zzlliibb. This flag is _o_n by default when ssuuddoo is compiled with zzlliibb support. exec_background By default, ssuuddoo runs a command as the foreground process as long as ssuuddoo itself is running in the foreground. When the _e_x_e_c___b_a_c_k_g_r_o_u_n_d flag is enabled and the command is being run in a pty (due to I/O logging or the _u_s_e___p_t_y flag), the command will be run as a background process. Attempts to read from the controlling terminal (or to change terminal settings) will result in the command being suspended with the SIGTTIN signal (or SIGTTOU in the case of terminal settings). If this happens when ssuuddoo is a foreground process, the command will be granted the controlling terminal and resumed in the foreground with no user intervention required. The advantage of initially running the command in the background is that ssuuddoo need not read from the terminal unless the command explicitly requests it. Otherwise, any terminal input must be passed to the command, whether it has required it or not (the kernel buffers terminals so it is not possible to tell whether the command really wants the input). This is different from historic _s_u_d_o behavior or when the command is not being run in a pty. For this to work seamlessly, the operating system must support the automatic restarting of system calls. Unfortunately, not all operating systems do this by default, and even those that do may have bugs. For example, Mac OS X fails to restart the ttccggeettaattttrr() and ttccsseettaattttrr() system calls (this is a bug in Mac OS X). Furthermore, because this behavior depends on the command stopping with the SIGTTIN or SIGTTOU signals, programs that catch these signals and suspend themselves with a different signal (usually SIGTOP) will not be automatically foregrounded. Some versions of the linux su(1) command behave this way. This flag is _o_f_f by default. This setting is only supported by version 1.8.7 or higher. It has no effect unless I/O logging is enabled or the _u_s_e___p_t_y flag is enabled. env_editor If set, vviissuuddoo will use the value of the EDITOR or VISUAL environment variables before falling back on the default editor list. Note that this may create a security hole as it allows the user to run any arbitrary command as root without logging. A safer alternative is to place a colon-separated list of editors in the editor variable. vviissuuddoo will then only use the EDITOR or VISUAL if they match a value specified in editor. If the _e_n_v___r_e_s_e_t flag is enabled, the EDITOR and/or VISUAL environment variables must be present in the _e_n_v___k_e_e_p list for the _e_n_v___e_d_i_t_o_r flag to function when vviissuuddoo is invoked via ssuuddoo. This flag is _o_f_f by default. env_reset If set, ssuuddoo will run the command in a minimal environment containing the TERM, PATH, HOME, MAIL, SHELL, LOGNAME, USER, USERNAME and SUDO_* variables. Any variables in the caller's environment that match the env_keep and env_check lists are then added, followed by any variables present in the file specified by the _e_n_v___f_i_l_e option (if any). The contents of the env_keep and env_check lists, as modified by global Defaults parameters in _s_u_d_o_e_r_s, are displayed when ssuuddoo is run by root with the --VV option. If the _s_e_c_u_r_e___p_a_t_h option is set, its value will be used for the PATH environment variable. This flag is _o_n by default. fast_glob Normally, ssuuddoo uses the glob(3) function to do shell- style globbing when matching path names. However, since it accesses the file system, glob(3) can take a long time to complete for some patterns, especially when the pattern references a network file system that is mounted on demand (auto mounted). The _f_a_s_t___g_l_o_b option causes ssuuddoo to use the fnmatch(3) function, which does not access the file system to do its matching. The disadvantage of _f_a_s_t___g_l_o_b is that it is unable to match relative path names such as _._/_l_s or _._._/_b_i_n_/_l_s. This has security implications when path names that include globbing characters are used with the negation operator, `!', as such rules can be trivially bypassed. As such, this option should not be used when the _s_u_d_o_e_r_s file contains rules that contain negated path names which include globbing characters. This flag is _o_f_f by default. fqdn Set this flag if you want to put fully qualified host names in the _s_u_d_o_e_r_s file when the local host name (as returned by the hostname command) does not contain the domain name. In other words, instead of myhost you would use myhost.mydomain.edu. You may still use the short form if you wish (and even mix the two). This option is only effective when the ``canonical'' host name, as returned by the ggeettaaddddrriinnffoo() or ggeetthhoossttbbyynnaammee() function, is a fully-qualified domain name. This is usually the case when the system is configured to use DNS for host name resolution. If the system is configured to use the _/_e_t_c_/_h_o_s_t_s file in preference to DNS, the ``canonical'' host name may not be fully-qualified. The order that sources are queried for host name resolution is usually specified in the _/_e_t_c_/_n_s_s_w_i_t_c_h_._c_o_n_f, _/_e_t_c_/_n_e_t_s_v_c_._c_o_n_f, _/_e_t_c_/_h_o_s_t_._c_o_n_f, or, in some cases, _/_e_t_c_/_r_e_s_o_l_v_._c_o_n_f file. In the _/_e_t_c_/_h_o_s_t_s file, the first host name of the entry is considered to be the ``canonical'' name; subsequent names are aliases that are not used by ssuuddooeerrss. For example, the following hosts file line for the machine ``xyzzy'' has the fully-qualified domain name as the ``canonical'' host name, and the short version as an alias. 192.168.1.1 xyzzy.sudo.ws xyzzy If the machine's hosts file entry is not formatted properly, the _f_q_d_n option will not be effective if it is queried before DNS. Beware that when using DNS for host name resolution, turning on _f_q_d_n requires ssuuddooeerrss to make DNS lookups which renders ssuuddoo unusable if DNS stops working (for example if the machine is disconnected from the network). Also note that just like with the hosts file, you must use the ``canonical'' name as DNS knows it. That is, you may not use a host alias (CNAME entry) due to performance issues and the fact that there is no way to get all aliases from DNS. This flag is _o_f_f by default. ignore_dot If set, ssuuddoo will ignore "." or "" (both denoting current directory) in the PATH environment variable; the PATH itself is not modified. This flag is _o_f_f by default. ignore_local_sudoers If set via LDAP, parsing of _/_e_t_c_/_s_u_d_o_e_r_s will be skipped. This is intended for Enterprises that wish to prevent the usage of local sudoers files so that only LDAP is used. This thwarts the efforts of rogue operators who would attempt to add roles to _/_e_t_c_/_s_u_d_o_e_r_s. When this option is present, _/_e_t_c_/_s_u_d_o_e_r_s does not even need to exist. Since this option tells ssuuddoo how to behave when no specific LDAP entries have been matched, this sudoOption is only meaningful for the cn=defaults section. This flag is _o_f_f by default. insults If set, ssuuddoo will insult users when they enter an incorrect password. This flag is _o_f_f by default. log_host If set, the host name will be logged in the (non- syslog) ssuuddoo log file. This flag is _o_f_f by default. log_input If set, ssuuddoo will run the command in a pseudo-tty and log all user input. If the standard input is not connected to the user's tty, due to I/O redirection or because the command is part of a pipeline, that input is also captured and stored in a separate log file. For more information, see the _I_/_O _L_O_G _F_I_L_E_S section. This flag is _o_f_f by default. log_output If set, ssuuddoo will run the command in a pseudo-tty and log all output that is sent to the screen, similar to the script(1) command. For more information, see the _I_/_O _L_O_G _F_I_L_E_S section. This flag is _o_f_f by default. log_year If set, the four-digit year will be logged in the (non- syslog) ssuuddoo log file. This flag is _o_f_f by default. long_otp_prompt When validating with a One Time Password (OTP) scheme such as SS//KKeeyy or OOPPIIEE, a two-line prompt is used to make it easier to cut and paste the challenge to a local window. It's not as pretty as the default but some people find it more convenient. This flag is _o_f_f by default. mail_all_cmnds Send mail to the _m_a_i_l_t_o user every time a user attempts to run a command via ssuuddoo (this includes ssuuddooeeddiitt). No mail will be sent if the user runs ssuuddoo with the --ll or --vv option unless there is an authentication error and the _m_a_i_l___b_a_d_p_a_s_s flag is also set. This flag is _o_f_f by default. mail_always Send mail to the _m_a_i_l_t_o user every time a user runs ssuuddoo. This flag is _o_f_f by default. mail_badpass Send mail to the _m_a_i_l_t_o user if the user running ssuuddoo does not enter the correct password. If the command the user is attempting to run is not permitted by ssuuddooeerrss and one of the _m_a_i_l___a_l_l___c_m_n_d_s, _m_a_i_l___a_l_w_a_y_s, _m_a_i_l___n_o___h_o_s_t, _m_a_i_l___n_o___p_e_r_m_s or _m_a_i_l___n_o___u_s_e_r flags are set, this flag will have no effect. This flag is _o_f_f by default. mail_no_host If set, mail will be sent to the _m_a_i_l_t_o user if the invoking user exists in the _s_u_d_o_e_r_s file, but is not allowed to run commands on the current host. This flag is _o_f_f by default. mail_no_perms If set, mail will be sent to the _m_a_i_l_t_o user if the invoking user is allowed to use ssuuddoo but the command they are trying is not listed in their _s_u_d_o_e_r_s file entry or is explicitly denied. This flag is _o_f_f by default. mail_no_user If set, mail will be sent to the _m_a_i_l_t_o user if the invoking user is not in the _s_u_d_o_e_r_s file. This flag is _o_n by default. netgroup_tuple If set, netgroup lookups will be performed using the full netgroup tuple: host name, user name and domain (if one is set). Historically, ssuuddoo only matched the user name and domain for netgroups used in a User_List and only matched the host name and domain for netgroups used in a Host_List. This flag is _o_f_f by default. noexec If set, all commands run via ssuuddoo will behave as if the NOEXEC tag has been set, unless overridden by an EXEC tag. See the description of _E_X_E_C _a_n_d _N_O_E_X_E_C above as well as the _P_r_e_v_e_n_t_i_n_g _s_h_e_l_l _e_s_c_a_p_e_s section at the end of this manual. This flag is _o_f_f by default. pam_session On systems that use PAM for authentication, ssuuddoo will create a new PAM session for the command to be run in. Disabling _p_a_m___s_e_s_s_i_o_n may be needed on older PAM implementations or on operating systems where opening a PAM session changes the utmp or wtmp files. If PAM session support is disabled, resource limits may not be updated for the command being run. If _p_a_m___s_e_s_s_i_o_n, _p_a_m___s_e_t_c_r_e_d, and _u_s_e___p_t_y are disabled and I/O logging has not been configured, ssuuddoo will execute the command directly instead of running it as a child process. This flag is _o_n by default. This setting is only supported by version 1.8.7 or higher. pam_setcred On systems that use PAM for authentication, ssuuddoo will attempt to establish credentials for the target user by default, if supported by the underlying authentication system. One example of a credential is a Kerberos ticket. If _p_a_m___s_e_s_s_i_o_n, _p_a_m___s_e_t_c_r_e_d, and _u_s_e___p_t_y are disabled and I/O logging has not been configured, ssuuddoo will execute the command directly instead of running it as a child process. This flag is _o_n by default. This setting is only supported by version 1.8.8 or higher. passprompt_override The password prompt specified by _p_a_s_s_p_r_o_m_p_t will normally only be used if the password prompt provided by systems such as PAM matches the string ``Password:''. If _p_a_s_s_p_r_o_m_p_t___o_v_e_r_r_i_d_e is set, _p_a_s_s_p_r_o_m_p_t will always be used. This flag is _o_f_f by default. path_info Normally, ssuuddoo will tell the user when a command could not be found in their PATH environment variable. Some sites may wish to disable this as it could be used to gather information on the location of executables that the normal user does not have access to. The disadvantage is that if the executable is simply not in the user's PATH, ssuuddoo will tell the user that they are not allowed to run it, which can be confusing. This flag is _o_n by default. preserve_groups By default, ssuuddoo will initialize the group vector to the list of groups the target user is in. When _p_r_e_s_e_r_v_e___g_r_o_u_p_s is set, the user's existing group vector is left unaltered. The real and effective group IDs, however, are still set to match the target user. This flag is _o_f_f by default. pwfeedback By default, ssuuddoo reads the password like most other Unix programs, by turning off echo until the user hits the return (or enter) key. Some users become confused by this as it appears to them that ssuuddoo has hung at this point. When _p_w_f_e_e_d_b_a_c_k is set, ssuuddoo will provide visual feedback when the user presses a key. Note that this does have a security impact as an onlooker may be able to determine the length of the password being entered. This flag is _o_f_f by default. requiretty If set, ssuuddoo will only run when the user is logged in to a real tty. When this flag is set, ssuuddoo can only be run from a login session and not via other means such as cron(1m) or cgi-bin scripts. This flag is _o_f_f by default. root_sudo If set, root is allowed to run ssuuddoo too. Disabling this prevents users from ``chaining'' ssuuddoo commands to get a root shell by doing something like ``sudo sudo /bin/sh''. Note, however, that turning off _r_o_o_t___s_u_d_o will also prevent root from running ssuuddooeeddiitt. Disabling _r_o_o_t___s_u_d_o provides no real additional security; it exists purely for historical reasons. This flag is _o_n by default. rootpw If set, ssuuddoo will prompt for the root password instead of the password of the invoking user when running a command or editing a file. This flag is _o_f_f by default. runaspw If set, ssuuddoo will prompt for the password of the user defined by the _r_u_n_a_s___d_e_f_a_u_l_t option (defaults to root) instead of the password of the invoking user when running a command or editing a file. This flag is _o_f_f by default. set_home If enabled and ssuuddoo is invoked with the --ss option the HOME environment variable will be set to the home directory of the target user (which is root unless the --uu option is used). This effectively makes the --ss option imply --HH. Note that HOME is already set when the _e_n_v___r_e_s_e_t option is enabled, so _s_e_t___h_o_m_e is only effective for configurations where either _e_n_v___r_e_s_e_t is disabled or HOME is present in the _e_n_v___k_e_e_p list. This flag is _o_f_f by default. set_logname Normally, ssuuddoo will set the LOGNAME, USER and USERNAME environment variables to the name of the target user (usually root unless the --uu option is given). However, since some programs (including the RCS revision control system) use LOGNAME to determine the real identity of the user, it may be desirable to change this behavior. This can be done by negating the set_logname option. Note that _s_e_t___l_o_g_n_a_m_e will have no effect if the _e_n_v___r_e_s_e_t option has not been disabled and the _e_n_v___k_e_e_p list contains LOGNAME, USER or USERNAME. This flag is _o_n by default. set_utmp When enabled, ssuuddoo will create an entry in the utmp (or utmpx) file when a pseudo-tty is allocated. A pseudo- tty is allocated by ssuuddoo when the _l_o_g___i_n_p_u_t, _l_o_g___o_u_t_p_u_t or _u_s_e___p_t_y flags are enabled. By default, the new entry will be a copy of the user's existing utmp entry (if any), with the tty, time, type and pid fields updated. This flag is _o_n by default. setenv Allow the user to disable the _e_n_v___r_e_s_e_t option from the command line via the --EE option. Additionally, environment variables set via the command line are not subject to the restrictions imposed by _e_n_v___c_h_e_c_k, _e_n_v___d_e_l_e_t_e, or _e_n_v___k_e_e_p. As such, only trusted users should be allowed to set variables in this manner. This flag is _o_f_f by default. shell_noargs If set and ssuuddoo is invoked with no arguments it acts as if the --ss option had been given. That is, it runs a shell as root (the shell is determined by the SHELL environment variable if it is set, falling back on the shell listed in the invoking user's /etc/passwd entry if not). This flag is _o_f_f by default. stay_setuid Normally, when ssuuddoo executes a command the real and effective UIDs are set to the target user (root by default). This option changes that behavior such that the real UID is left as the invoking user's UID. In other words, this makes ssuuddoo act as a setuid wrapper. This can be useful on systems that disable some potentially dangerous functionality when a program is run setuid. This option is only effective on systems that support either the setreuid(2) or setresuid(2) system call. This flag is _o_f_f by default. sudoedit_checkdir If set, ssuuddooeeddiitt will check all directory components of the path to be edited for writability by the invoking user. Symbolic links will not be followed in writable directories and ssuuddooeeddiitt will refuse to edit a file located in a writable directory. These restrictions are not enforced when ssuuddooeeddiitt is run by root. On some systems, if all directory components of the path to be edited are not readable by the target user, ssuuddooeeddiitt will be unable to edit the file. This flag is _o_n by default. This setting was first introduced in version 1.8.15 but initially suffered from a race condition. The check for symbolic links in writable intermediate directories was added in version 1.8.16. sudoedit_follow By default, ssuuddooeeddiitt will not follow symbolic links when opening files. The _s_u_d_o_e_d_i_t___f_o_l_l_o_w option can be enabled to allow ssuuddooeeddiitt to open symbolic links. It may be overridden on a per-command basis by the _F_O_L_L_O_W and _N_O_F_O_L_L_O_W tags. This flag is _o_f_f by default. This setting is only supported by version 1.8.15 or higher. targetpw If set, ssuuddoo will prompt for the password of the user specified by the --uu option (defaults to root) instead of the password of the invoking user when running a command or editing a file. Note that this flag precludes the use of a uid not listed in the passwd database as an argument to the --uu option. This flag is _o_f_f by default. tty_tickets If set, users must authenticate on a per-tty basis. With this flag enabled, ssuuddoo will use a separate record in the time stamp file for each tty. If disabled, a single record is used for all login sessions. This flag is _o_n by default. umask_override If set, ssuuddoo will set the umask as specified in the _s_u_d_o_e_r_s file without modification. This makes it possible to specify a umask in the _s_u_d_o_e_r_s file that is more permissive than the user's own umask and matches historical behavior. If _u_m_a_s_k___o_v_e_r_r_i_d_e is not set, ssuuddoo will set the umask to be the union of the user's umask and what is specified in _s_u_d_o_e_r_s. This flag is _o_f_f by default. use_loginclass If set, ssuuddoo will apply the defaults specified for the target user's login class if one exists. Only available if ssuuddoo is configured with the --with-logincap option. This flag is _o_f_f by default. use_netgroups If set, netgroups (prefixed with `+'), may be used in place of a user or host. For LDAP-based sudoers, netgroup support requires an expensive substring match on the server unless the NNEETTGGRROOUUPP__BBAASSEE directive is present in the _/_e_t_c_/_l_d_a_p_._c_o_n_f file. If netgroups are not needed, this option can be disabled to reduce the load on the LDAP server. This flag is _o_n by default. use_pty If set, ssuuddoo will run the command in a pseudo-pty even if no I/O logging is being gone. A malicious program run under ssuuddoo could conceivably fork a background process that retains to the user's terminal device after the main program has finished executing. Use of this option will make that impossible. This flag is _o_f_f by default. utmp_runas If set, ssuuddoo will store the name of the runas user when updating the utmp (or utmpx) file. By default, ssuuddoo stores the name of the invoking user. This flag is _o_f_f by default. visiblepw By default, ssuuddoo will refuse to run if the user must enter a password but it is not possible to disable echo on the terminal. If the _v_i_s_i_b_l_e_p_w flag is set, ssuuddoo will prompt for a password even when it would be visible on the screen. This makes it possible to run things like ``ssh somehost sudo ls'' since by default, ssh(1) does not allocate a tty when running a command. This flag is _o_f_f by default. IInntteeggeerrss: closefrom Before it executes a command, ssuuddoo will close all open file descriptors other than standard input, standard output and standard error (ie: file descriptors 0-2). The _c_l_o_s_e_f_r_o_m option can be used to specify a different file descriptor at which to start closing. The default is 3. maxseq The maximum sequence number that will be substituted for the ``%{seq}'' escape in the I/O log file (see the _i_o_l_o_g___d_i_r description above for more information). While the value substituted for ``%{seq}'' is in base 36, _m_a_x_s_e_q itself should be expressed in decimal. Values larger than 2176782336 (which corresponds to the base 36 sequence number ``ZZZZZZ'') will be silently truncated to 2176782336. The default value is 2176782336. Once the local sequence number reaches the value of _m_a_x_s_e_q, it will ``roll over'' to zero, after which ssuuddooeerrss will truncate and re-use any existing I/O log path names. This setting is only supported by version 1.8.7 or higher. passwd_tries The number of tries a user gets to enter his/her password before ssuuddoo logs the failure and exits. The default is 3. IInntteeggeerrss tthhaatt ccaann bbee uusseedd iinn aa bboooolleeaann ccoonntteexxtt: loglinelen Number of characters per line for the file log. This value is used to decide when to wrap lines for nicer log files. This has no effect on the syslog log file, only the file log. The default is 80 (use 0 or negate the option to disable word wrap). passwd_timeout Number of minutes before the ssuuddoo password prompt times out, or 0 for no timeout. The timeout may include a fractional component if minute granularity is insufficient, for example 2.5. The default is 5. timestamp_timeout Number of minutes that can elapse before ssuuddoo will ask for a passwd again. The timeout may include a fractional component if minute granularity is insufficient, for example 2.5. The default is 5. Set this to 0 to always prompt for a password. If set to a value less than 0 the user's time stamp will not expire until the system is rebooted. This can be used to allow users to create or delete their own time stamps via ``sudo -v'' and ``sudo -k'' respectively. umask Umask to use when running the command. Negate this option or set it to 0777 to preserve the user's umask. The actual umask that is used will be the union of the user's umask and the value of the _u_m_a_s_k option, which defaults to 0022. This guarantees that ssuuddoo never lowers the umask when running a command. Note: on systems that use PAM, the default PAM configuration may specify its own umask which will override the value set in _s_u_d_o_e_r_s. SSttrriinnggss: badpass_message Message that is displayed if a user enters an incorrect password. The default is Sorry, try again. unless insults are enabled. editor A colon (`:') separated list of editors allowed to be used with vviissuuddoo. vviissuuddoo will choose the editor that matches the user's EDITOR or VISUAL environment variable if possible, or the first editor in the list that exists and is executable. Note that the EDITOR and VISUAL environment variables are not preserved by default when the _e_n_v___r_e_s_e_t option is enabled. The default is _v_i. iolog_dir The top-level directory to use when constructing the path name for the input/output log directory. Only used if the _l_o_g___i_n_p_u_t or _l_o_g___o_u_t_p_u_t options are enabled or when the LOG_INPUT or LOG_OUTPUT tags are present for a command. The session sequence number, if any, is stored in the directory. The default is _/_v_a_r_/_l_o_g_/_s_u_d_o_-_i_o. The following percent (`%') escape sequences are supported: %{seq} expanded to a monotonically increasing base-36 sequence number, such as 0100A5, where every two digits are used to form a new directory, e.g. _0_1_/_0_0_/_A_5 %{user} expanded to the invoking user's login name %{group} expanded to the name of the invoking user's real group ID %{runas_user} expanded to the login name of the user the command will be run as (e.g. root) %{runas_group} expanded to the group name of the user the command will be run as (e.g. wheel) %{hostname} expanded to the local host name without the domain name %{command} expanded to the base name of the command being run In addition, any escape sequences supported by the system's strftime(3) function will be expanded. To include a literal `%' character, the string `%%' should be used. iolog_file The path name, relative to _i_o_l_o_g___d_i_r, in which to store input/output logs when the _l_o_g___i_n_p_u_t or _l_o_g___o_u_t_p_u_t options are enabled or when the LOG_INPUT or LOG_OUTPUT tags are present for a command. Note that _i_o_l_o_g___f_i_l_e may contain directory components. The default is ``%{seq}''. See the _i_o_l_o_g___d_i_r option above for a list of supported percent (`%') escape sequences. In addition to the escape sequences, path names that end in six or more Xs will have the Xs replaced with a unique combination of digits and letters, similar to the mktemp(3) function. If the path created by concatenating _i_o_l_o_g___d_i_r and _i_o_l_o_g___f_i_l_e already exists, the existing I/O log file will be truncated and overwritten unless _i_o_l_o_g___f_i_l_e ends in six or more Xs. lecture_status_dir The directory in which ssuuddoo stores per-user lecture status files. Once a user has received the lecture, a zero-length file is created in this directory so that ssuuddoo will not lecture the user again. This directory should _n_o_t be cleared when the system reboots. The default is _/_v_a_r_/_a_d_m_/_s_u_d_o_/_l_e_c_t_u_r_e_d. limitprivs The default Solaris limit privileges to use when constructing a new privilege set for a command. This bounds all privileges of the executing process. The default limit privileges may be overridden on a per- command basis in _s_u_d_o_e_r_s. This option is only available if ssuuddooeerrss is built on Solaris 10 or higher. mailsub Subject of the mail sent to the _m_a_i_l_t_o user. The escape %h will expand to the host name of the machine. Default is ``*** SECURITY information for %h ***''. noexec_file As of ssuuddoo version 1.8.1 this option is no longer supported. The path to the noexec file should now be set in the sudo.conf(4) file. pam_login_service On systems that use PAM for authentication, this is the service name used when the --ii option is specified. The default value is ``sudo''. See the description of _p_a_m___s_e_r_v_i_c_e for more information. This setting is only supported by version 1.8.8 or higher. pam_service On systems that use PAM for authentication, the service name specifies the PAM policy to apply. This usually corresponds to an entry in the _p_a_m_._c_o_n_f file or a file in the _/_e_t_c_/_p_a_m_._d directory. The default value is ``sudo''. This setting is only supported by version 1.8.8 or higher. passprompt The default prompt to use when asking for a password; can be overridden via the --pp option or the SUDO_PROMPT environment variable. The following percent (`%') escape sequences are supported: %H expanded to the local host name including the domain name (only if the machine's host name is fully qualified or the _f_q_d_n option is set) %h expanded to the local host name without the domain name %p expanded to the user whose password is being asked for (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) %U expanded to the login name of the user the command will be run as (defaults to root) %u expanded to the invoking user's login name %% two consecutive % characters are collapsed into a single % character The default value is ``Password:''. privs The default Solaris privileges to use when constructing a new privilege set for a command. This is passed to the executing process via the inherited privilege set, but is bounded by the limit privileges. If the _p_r_i_v_s option is specified but the _l_i_m_i_t_p_r_i_v_s option is not, the limit privileges of the executing process is set to _p_r_i_v_s. The default privileges may be overridden on a per-command basis in _s_u_d_o_e_r_s. This option is only available if ssuuddooeerrss is built on Solaris 10 or higher. role The default SELinux role to use when constructing a new security context to run the command. The default role may be overridden on a per-command basis in the _s_u_d_o_e_r_s file or via command line options. This option is only available when ssuuddoo is built with SELinux support. runas_default The default user to run commands as if the --uu option is not specified on the command line. This defaults to root. syslog_badpri Syslog priority to use when user authenticates unsuccessfully. Defaults to alert. The following syslog priorities are supported: aalleerrtt, ccrriitt, ddeebbuugg, eemmeerrgg, eerrrr, iinnffoo, nnoottiiccee, and wwaarrnniinngg. syslog_goodpri Syslog priority to use when user authenticates successfully. Defaults to notice. See _s_y_s_l_o_g___b_a_d_p_r_i for the list of supported syslog priorities. sudoers_locale Locale to use when parsing the sudoers file, logging commands, and sending email. Note that changing the locale may affect how sudoers is interpreted. Defaults to ``C''. timestampdir The directory in which ssuuddoo stores its time stamp files. This directory should be cleared when the system reboots. The default is _/_v_a_r_/_r_u_n_/_s_u_d_o_/_t_s. timestampowner The owner of the lecture status directory, time stamp directory and all files stored therein. The default is root. type The default SELinux type to use when constructing a new security context to run the command. The default type may be overridden on a per-command basis in the _s_u_d_o_e_r_s file or via command line options. This option is only available when ssuuddoo is built with SELinux support. SSttrriinnggss tthhaatt ccaann bbee uusseedd iinn aa bboooolleeaann ccoonntteexxtt: env_file The _e_n_v___f_i_l_e option specifies the fully qualified path to a file containing variables to be set in the environment of the program being run. Entries in this file should either be of the form ``VARIABLE=value'' or ``export VARIABLE=value''. The value may optionally be surrounded by single or double quotes. Variables in this file are subject to other ssuuddoo environment settings such as _e_n_v___k_e_e_p and _e_n_v___c_h_e_c_k. exempt_group Users in this group are exempt from password and PATH requirements. The group name specified should not include a % prefix. This is not set by default. group_plugin A string containing a ssuuddooeerrss group plugin with optional arguments. The string should consist of the plugin path, either fully-qualified or relative to the _/_u_s_r_/_l_o_c_a_l_/_l_i_b_e_x_e_c_/_s_u_d_o directory, followed by any configuration arguments the plugin requires. These arguments (if any) will be passed to the plugin's initialization function. If arguments are present, the string must be enclosed in double quotes (""). For more information see GROUP PROVIDER PLUGINS. lecture This option controls when a short lecture will be printed along with the password prompt. It has the following possible values: always Always lecture the user. never Never lecture the user. once Only lecture the user the first time they run ssuuddoo. If no value is specified, a value of _o_n_c_e is implied. Negating the option results in a value of _n_e_v_e_r being used. The default value is _o_n_c_e. lecture_file Path to a file containing an alternate ssuuddoo lecture that will be used in place of the standard lecture if the named file exists. By default, ssuuddoo uses a built-in lecture. listpw This option controls when a password will be required when a user runs ssuuddoo with the --ll option. It has the following possible values: all All the user's _s_u_d_o_e_r_s file entries for the current host must have the NOPASSWD flag set to avoid entering a password. always The user must always enter a password to use the --ll option. any At least one of the user's _s_u_d_o_e_r_s file entries for the current host must have the NOPASSWD flag set to avoid entering a password. never The user need never enter a password to use the --ll option. If no value is specified, a value of _a_n_y is implied. Negating the option results in a value of _n_e_v_e_r being used. The default value is _a_n_y. logfile Path to the ssuuddoo log file (not the syslog log file). Setting a path turns on logging to a file; negating this option turns it off. By default, ssuuddoo logs via syslog. mailerflags Flags to use when invoking mailer. Defaults to --tt. mailerpath Path to mail program used to send warning mail. Defaults to the path to sendmail found at configure time. mailfrom Address to use for the ``from'' address when sending warning and error mail. The address should be enclosed in double quotes ("") to protect against ssuuddoo interpreting the @ sign. Defaults to the name of the user running ssuuddoo. mailto Address to send warning and error mail to. The address should be enclosed in double quotes ("") to protect against ssuuddoo interpreting the @ sign. Defaults to root. secure_path Path used for every command run from ssuuddoo. If you don't trust the people running ssuuddoo to have a sane PATH environment variable you may want to use this. Another use is if you want to have the ``root path'' be separate from the ``user path''. Users in the group specified by the _e_x_e_m_p_t___g_r_o_u_p option are not affected by _s_e_c_u_r_e___p_a_t_h. This option is not set by default. syslog Syslog facility if syslog is being used for logging (negate to disable syslog logging). Defaults to auth. The following syslog facilities are supported: aauutthhpprriivv (if your OS supports it), aauutthh, ddaaeemmoonn, uusseerr, llooccaall00, llooccaall11, llooccaall22, llooccaall33, llooccaall44, llooccaall55, llooccaall66, and llooccaall77. verifypw This option controls when a password will be required when a user runs ssuuddoo with the --vv option. It has the following possible values: all All the user's _s_u_d_o_e_r_s file entries for the current host must have the NOPASSWD flag set to avoid entering a password. always The user must always enter a password to use the --vv option. any At least one of the user's _s_u_d_o_e_r_s file entries for the current host must have the NOPASSWD flag set to avoid entering a password. never The user need never enter a password to use the --vv option. If no value is specified, a value of _a_l_l is implied. Negating the option results in a value of _n_e_v_e_r being used. The default value is _a_l_l. LLiissttss tthhaatt ccaann bbee uusseedd iinn aa bboooolleeaann ccoonntteexxtt: env_check Environment variables to be removed from the user's environment unless they are considered ``safe''. For all variables except TZ, ``safe'' means that the variable's value does not contain any `%' or `/' characters. This can be used to guard against printf- style format vulnerabilities in poorly-written programs. The TZ variable is considered unsafe if any of the following are true: ++oo It consists of a fully-qualified path name, optionally prefixed with a colon (`:'), that does not match the location of the _z_o_n_e_i_n_f_o directory. ++oo It contains a _._. path element. ++oo It contains white space or non-printable characters. ++oo It is longer than the value of PATH_MAX. The argument may be a double-quoted, space-separated list or a single value without double-quotes. The list can be replaced, added to, deleted from, or disabled by using the =, +=, -=, and ! operators respectively. Regardless of whether the env_reset option is enabled or disabled, variables specified by env_check will be preserved in the environment if they pass the aforementioned check. The global list of environment variables to check is displayed when ssuuddoo is run by root with the --VV option. env_delete Environment variables to be removed from the user's environment when the _e_n_v___r_e_s_e_t option is not in effect. The argument may be a double-quoted, space-separated list or a single value without double-quotes. The list can be replaced, added to, deleted from, or disabled by using the =, +=, -=, and ! operators respectively. The global list of environment variables to remove is displayed when ssuuddoo is run by root with the --VV option. Note that many operating systems will remove potentially dangerous variables from the environment of any setuid process (such as ssuuddoo). env_keep Environment variables to be preserved in the user's environment when the _e_n_v___r_e_s_e_t option is in effect. This allows fine-grained control over the environment ssuuddoo-spawned processes will receive. The argument may be a double-quoted, space-separated list or a single value without double-quotes. The list can be replaced, added to, deleted from, or disabled by using the =, +=, -=, and ! operators respectively. The global list of variables to keep is displayed when ssuuddoo is run by root with the --VV option. GGRROOUUPP PPRROOVVIIDDEERR PPLLUUGGIINNSS The ssuuddooeerrss plugin supports its own plugin interface to allow non-Unix group lookups which can query a group source other than the standard Unix group database. This can be used to implement support for the nonunix_group syntax described earlier. Group provider plugins are specified via the _g_r_o_u_p___p_l_u_g_i_n Defaults setting. The argument to _g_r_o_u_p___p_l_u_g_i_n should consist of the plugin path, either fully-qualified or relative to the _/_u_s_r_/_l_o_c_a_l_/_l_i_b_e_x_e_c_/_s_u_d_o directory, followed by any configuration options the plugin requires. These options (if specified) will be passed to the plugin's initialization function. If options are present, the string must be enclosed in double quotes (""). The following group provider plugins are installed by default: group_file The _g_r_o_u_p___f_i_l_e plugin supports an alternate group file that uses the same syntax as the _/_e_t_c_/_g_r_o_u_p file. The path to the group file should be specified as an option to the plugin. For example, if the group file to be used is _/_e_t_c_/_s_u_d_o_-_g_r_o_u_p: Defaults group_plugin="group_file.so /etc/sudo-group" system_group The _s_y_s_t_e_m___g_r_o_u_p plugin supports group lookups via the standard C library functions ggeettggrrnnaamm() and ggeettggrriidd(). This plugin can be used in instances where the user belongs to groups not present in the user's supplemental group vector. This plugin takes no options: Defaults group_plugin=system_group.so The group provider plugin API is described in detail in sudo_plugin(1m). LLOOGG FFOORRMMAATT ssuuddooeerrss can log events using either syslog(3) or a simple log file. The log format is almost identical in both cases. 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 option. a password is required ssuuddoo's --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, ssuuddooeerrss 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 ssuuddooeerrss 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, ssuuddooeerrss tries to open the _s_u_d_o_e_r_s file using group permissions to avoid this problem. Consider either changing the ownership of _/_e_t_c_/_s_u_d_o_e_r_s or adding an argument like ``sudoers_uid=N'' (where `N' is the user ID that owns the _s_u_d_o_e_r_s file) to the end of the ssuuddooeerrss Plugin line in the sudo.conf(4) file. 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. If you wish to change the _s_u_d_o_e_r_s file owner, please add ``sudoers_uid=N'' (where `N' is the user ID that owns the _s_u_d_o_e_r_s file) to the ssuuddooeerrss Plugin line in the sudo.conf(4) file. /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). The default mode may be changed via the ``sudoers_mode'' option to the ssuuddooeerrss Plugin line in the sudo.conf(4) file. /etc/sudoers is owned by gid N, should be 1 The _s_u_d_o_e_r_s file has the wrong group ownership. If you wish to change the _s_u_d_o_e_r_s file group ownership, please add ``sudoers_gid=N'' (where `N' is the group ID that owns the _s_u_d_o_e_r_s file) to the ssuuddooeerrss Plugin line in the sudo.conf(4) file. unable to open /var/run/sudo/ts/username ssuuddooeerrss was unable to read or create the user's time stamp file. This can happen when _t_i_m_e_s_t_a_m_p_o_w_n_e_r is set to a user other than root and the mode on _/_v_a_r_/_r_u_n_/_s_u_d_o is not searchable by group or other. The default mode for _/_v_a_r_/_r_u_n_/_s_u_d_o is 0711. unable to write to /var/run/sudo/ts/username ssuuddooeerrss was unable to write to the user's time stamp file. /var/run/sudo/ts is owned by uid X, should be Y The time stamp directory is owned by a user other than _t_i_m_e_s_t_a_m_p_o_w_n_e_r. This can occur when the value of _t_i_m_e_s_t_a_m_p_o_w_n_e_r has been changed. ssuuddooeerrss will ignore the time stamp directory until the owner is corrected. /var/run/sudo/ts is group writable The time stamp directory is group-writable; it should be writable only by _t_i_m_e_s_t_a_m_p_o_w_n_e_r. The default mode for the time stamp directory is 0700. ssuuddooeerrss will ignore the time stamp directory until the mode is corrected. NNootteess oonn llooggggiinngg vviiaa ssyysslloogg By default, ssuuddooeerrss 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 ssuuddooeerrss 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, ssuuddooeerrss 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, ssuuddooeerrss will log to a local file, such as _/_v_a_r_/_l_o_g_/_s_u_d_o. When logging to a file, ssuuddooeerrss 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 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 option is set to 0 (or negated with a `!'), word wrap will be disabled. II//OO LLOOGG FFIILLEESS When I/O logging is enabled, ssuuddoo will run the command in a pseudo-tty and log all user input and/or output. I/O is logged to the directory specified by the _i_o_l_o_g___d_i_r option (_/_v_a_r_/_l_o_g_/_s_u_d_o_-_i_o by default) using a unique session ID that is included in the ssuuddoo log line, prefixed with ``TSID=''. The _i_o_l_o_g___f_i_l_e option may be used to control the format of the session ID. Each I/O log is stored in a separate directory that contains the following files: _l_o_g a text file containing the time the command was run, the name of the user who ran ssuuddoo, the name of the target user, the name of the target group (optional), the terminal that ssuuddoo was run from, the number of rows and columns of the terminal, the working directory the command was run from and the path name of the command itself (with arguments if present) _t_i_m_i_n_g a log of the amount of time between, and the number of bytes in, each I/O log entry (used for session playback) _t_t_y_i_n input from the user's tty (what the user types) _s_t_d_i_n input from a pipe or file _t_t_y_o_u_t output from the pseudo-tty (what the command writes to the screen) _s_t_d_o_u_t standard output to a pipe or redirected to a file _s_t_d_e_r_r standard error to a pipe or redirected to a file All files other than _l_o_g are compressed in gzip format unless the _c_o_m_p_r_e_s_s___i_o option has been disabled. Due to buffering, the I/O log data will not be complete until the ssuuddoo command has completed. The output portion of an I/O log file can be viewed with the sudoreplay(1m) utility, which can also be used to list or search the available logs. Note that user input may contain sensitive information such as passwords (even if they are not echoed to the screen), which will be stored in the log file unencrypted. In most cases, logging the command output via _l_o_g___o_u_t_p_u_t or LOG_OUTPUT is all that is required. Since each session's I/O logs are stored in a separate directory, traditional log rotation utilities cannot be used to limit the number of I/O logs. The simplest way to limit the number of I/O is by setting the _m_a_x_s_e_q option to the maximum number of logs you wish to store. Once the I/O log sequence number reaches _m_a_x_s_e_q, it will be reset to zero and ssuuddooeerrss will truncate and re-use any existing I/O logs. FFIILLEESS _/_e_t_c_/_s_u_d_o_._c_o_n_f Sudo front end configuration _/_e_t_c_/_s_u_d_o_e_r_s List of who can run what _/_e_t_c_/_g_r_o_u_p Local groups file _/_e_t_c_/_n_e_t_g_r_o_u_p List of network groups _/_v_a_r_/_l_o_g_/_s_u_d_o_-_i_o I/O log files _/_v_a_r_/_r_u_n_/_s_u_d_o_/_t_s Directory containing time stamps for the ssuuddooeerrss security policy _/_v_a_r_/_a_d_m_/_s_u_d_o_/_l_e_c_t_u_r_e_d Directory containing lecture status files for the ssuuddooeerrss security policy _/_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 Below are example _s_u_d_o_e_r_s file entries. Admittedly, some of these are a bit contrived. First, we allow a few environment variables to pass and then define our _a_l_i_a_s_e_s: # Run X applications through sudo; HOME is used to find the # .Xauthority file. Note that other programs use HOME to find # configuration files and this may lead to privilege escalation! Defaults env_keep += "DISPLAY HOME" # User alias specification User_Alias FULLTIMERS = millert, mikef, dowdy User_Alias PARTTIMERS = bostley, jwfox, crawl User_Alias WEBMASTERS = will, wendy, wim # Runas alias specification Runas_Alias OP = root, operator Runas_Alias DB = oracle, sybase Runas_Alias ADMINGRP = adm, oper # Host alias specification Host_Alias SPARC = bigtime, eclipse, moet, anchor :\ SGI = grolsch, dandelion, black :\ ALPHA = widget, thalamus, foobar :\ HPPA = boa, nag, python Host_Alias CUNETS = 128.138.0.0/255.255.0.0 Host_Alias CSNETS = 128.138.243.0, 128.138.204.0/24, 128.138.242.0 Host_Alias SERVERS = master, mail, www, ns Host_Alias CDROM = orion, perseus, hercules # Cmnd alias specification Cmnd_Alias DUMPS = /usr/bin/mt, /usr/sbin/dump, /usr/sbin/rdump,\ /usr/sbin/restore, /usr/sbin/rrestore,\ sha224:0GomF8mNN3wlDt1HD9XldjJ3SNgpFdbjO1+NsQ== \ /home/operator/bin/start_backups Cmnd_Alias KILL = /usr/bin/kill Cmnd_Alias PRINTING = /usr/sbin/lpc, /usr/bin/lprm Cmnd_Alias SHUTDOWN = /usr/sbin/shutdown Cmnd_Alias HALT = /usr/sbin/halt Cmnd_Alias REBOOT = /usr/sbin/reboot Cmnd_Alias SHELLS = /usr/bin/sh, /usr/bin/csh, /usr/bin/ksh,\ /usr/local/bin/tcsh, /usr/bin/rsh,\ /usr/local/bin/zsh Cmnd_Alias SU = /usr/bin/su Cmnd_Alias PAGERS = /usr/bin/more, /usr/bin/pg, /usr/bin/less Here we override some of the compiled in default values. We want ssuuddoo to log via syslog(3) using the _a_u_t_h facility in all cases. We don't want to subject the full time staff to the ssuuddoo lecture, user mmiilllleerrtt need not give a password, and we don't want to reset the LOGNAME, USER or USERNAME environment variables when running commands as root. Additionally, on the machines in the _S_E_R_V_E_R_S Host_Alias, we keep an additional local log file and make sure we log the year in each log line since the log entries will be kept around for several years. Lastly, we disable shell escapes for the commands in the PAGERS Cmnd_Alias (_/_u_s_r_/_b_i_n_/_m_o_r_e, _/_u_s_r_/_b_i_n_/_p_g and _/_u_s_r_/_b_i_n_/_l_e_s_s). Note that this will not effectively constrain users with ssuuddoo AALLLL privileges. # Override built-in defaults Defaults syslog=auth Defaults>root !set_logname Defaults:FULLTIMERS !lecture Defaults:millert !authenticate Defaults@SERVERS log_year, logfile=/var/log/sudo.log Defaults!PAGERS noexec The _U_s_e_r _s_p_e_c_i_f_i_c_a_t_i_o_n is the part that actually determines who may run what. root ALL = (ALL) ALL %wheel ALL = (ALL) ALL We let rroooott and any user in group wwhheeeell run any command on any host as any user. FULLTIMERS ALL = NOPASSWD: ALL Full time sysadmins (mmiilllleerrtt, mmiikkeeff, and ddoowwddyy) may run any command on any host without authenticating themselves. PARTTIMERS ALL = ALL Part time sysadmins bboossttlleeyy, jjwwffooxx, and ccrraawwll) may run any command on any host but they must authenticate themselves first (since the entry lacks the NOPASSWD tag). jack CSNETS = ALL The user jjaacckk may run any command on the machines in the _C_S_N_E_T_S alias (the networks 128.138.243.0, 128.138.204.0, and 128.138.242.0). Of those networks, only 128.138.204.0 has an explicit netmask (in CIDR notation) indicating it is a class C network. For the other networks in _C_S_N_E_T_S, the local machine's netmask will be used during matching. lisa CUNETS = ALL The user lliissaa may run any command on any host in the _C_U_N_E_T_S alias (the class B network 128.138.0.0). operator ALL = DUMPS, KILL, SHUTDOWN, HALT, REBOOT, PRINTING,\ sudoedit /etc/printcap, /usr/oper/bin/ The ooppeerraattoorr user may run commands limited to simple maintenance. Here, those are commands related to backups, killing processes, the printing system, shutting down the system, and any commands in the directory _/_u_s_r_/_o_p_e_r_/_b_i_n_/. Note that one command in the DUMPS Cmnd_Alias includes a sha224 digest, _/_h_o_m_e_/_o_p_e_r_a_t_o_r_/_b_i_n_/_s_t_a_r_t___b_a_c_k_u_p_s. This is because the directory containing the script is writable by the operator user. If the script is modified (resulting in a digest mismatch) it will no longer be possible to run it via ssuuddoo. joe ALL = /usr/bin/su operator The user jjooee may only su(1) to operator. pete HPPA = /usr/bin/passwd [A-Za-z]*, !/usr/bin/passwd root %opers ALL = (: ADMINGRP) /usr/sbin/ Users in the ooppeerrss group may run commands in _/_u_s_r_/_s_b_i_n_/ as themselves with any group in the _A_D_M_I_N_G_R_P Runas_Alias (the aaddmm and ooppeerr groups). The user ppeettee is allowed to change anyone's password except for root on the _H_P_P_A machines. Because command line arguments are matched as a single, concatenated string, the `*' wildcard will match _m_u_l_t_i_p_l_e words. This example assumes that passwd(1) does not take multiple user names on the command line. Note that on GNU systems, options to passwd(1) may be specified after the user argument. As a result, this rule will also allow: passwd username --expire which may not be desirable. bob SPARC = (OP) ALL : SGI = (OP) ALL The user bboobb may run anything on the _S_P_A_R_C and _S_G_I machines as any user listed in the _O_P Runas_Alias (rroooott and ooppeerraattoorr.) jim +biglab = ALL The user jjiimm may run any command on machines in the _b_i_g_l_a_b netgroup. ssuuddoo knows that ``biglab'' is a netgroup due to the `+' prefix. +secretaries ALL = PRINTING, /usr/bin/adduser, /usr/bin/rmuser Users in the sseeccrreettaarriieess netgroup need to help manage the printers as well as add and remove users, so they are allowed to run those commands on all machines. fred ALL = (DB) NOPASSWD: ALL The user ffrreedd can run commands as any user in the _D_B Runas_Alias (oorraaccllee or ssyybbaassee) without giving a password. john ALPHA = /usr/bin/su [!-]*, !/usr/bin/su *root* On the _A_L_P_H_A machines, user jjoohhnn may su to anyone except root but he is not allowed to specify any options to the su(1) command. jen ALL, !SERVERS = ALL The user jjeenn may run any command on any machine except for those in the _S_E_R_V_E_R_S Host_Alias (master, mail, www and ns). jill SERVERS = /usr/bin/, !SU, !SHELLS For any machine in the _S_E_R_V_E_R_S Host_Alias, jjiillll may run any commands in the directory _/_u_s_r_/_b_i_n_/ except for those commands belonging to the _S_U and _S_H_E_L_L_S Cmnd_Aliases. While not specifically mentioned in the rule, the commands in the _P_A_G_E_R_S Cmnd_Alias all reside in _/_u_s_r_/_b_i_n and have the _n_o_e_x_e_c option set. steve CSNETS = (operator) /usr/local/op_commands/ The user sstteevvee may run any command in the directory /usr/local/op_commands/ but only as user operator. matt valkyrie = KILL On his personal workstation, valkyrie, mmaatttt needs to be able to kill hung processes. WEBMASTERS www = (www) ALL, (root) /usr/bin/su www On the host www, any user in the _W_E_B_M_A_S_T_E_R_S User_Alias (will, wendy, and wim), may run any command as user www (which owns the web pages) or simply su(1) to www. ALL CDROM = NOPASSWD: /sbin/umount /CDROM,\ /sbin/mount -o nosuid\,nodev /dev/cd0a /CDROM Any user may mount or unmount a CD-ROM on the machines in the CDROM Host_Alias (orion, perseus, hercules) without entering a password. This is a bit tedious for users to type, so it is a prime candidate for encapsulating in a shell script. SSEECCUURRIITTYY NNOOTTEESS LLiimmiittaattiioonnss ooff tthhee ``!!'' ooppeerraattoorr It is generally not effective to ``subtract'' commands from AALLLL using the `!' operator. A user can trivially circumvent this by copying the desired command to a different name and then executing that. For example: bill ALL = ALL, !SU, !SHELLS Doesn't really prevent bbiillll from running the commands listed in _S_U or _S_H_E_L_L_S since he can simply copy those commands to a different name, or use a shell escape from an editor or other program. Therefore, these kind of restrictions should be considered advisory at best (and reinforced by policy). In general, if a user has sudo AALLLL there is nothing to prevent them from creating their own program that gives them a root shell (or making their own copy of a shell) regardless of any `!' elements in the user specification. SSeeccuurriittyy iimmpplliiccaattiioonnss ooff _f_a_s_t___g_l_o_b If the _f_a_s_t___g_l_o_b option is in use, it is not possible to reliably negate commands where the path name includes globbing (aka wildcard) characters. This is because the C library's fnmatch(3) function cannot resolve relative paths. While this is typically only an inconvenience for rules that grant privileges, it can result in a security issue for rules that subtract or revoke privileges. For example, given the following _s_u_d_o_e_r_s file entry: john ALL = /usr/bin/passwd [a-zA-Z0-9]*, /usr/bin/chsh [a-zA-Z0-9]*,\ /usr/bin/chfn [a-zA-Z0-9]*, !/usr/bin/* root User jjoohhnn can still run /usr/bin/passwd root if _f_a_s_t___g_l_o_b is enabled by changing to _/_u_s_r_/_b_i_n and running ./passwd root instead. PPrreevveennttiinngg sshheellll eessccaappeess Once ssuuddoo executes a program, that program is free to do whatever it pleases, including run other programs. This can be a security issue since it is not uncommon for a program to allow shell escapes, which lets a user bypass ssuuddoo's access control and logging. Common programs that permit shell escapes include shells (obviously), editors, paginators, mail and terminal programs. There are two basic approaches to this problem: restrict Avoid giving users access to commands that allow the user to run arbitrary commands. Many editors have a restricted mode where shell escapes are disabled, though ssuuddooeeddiitt is a better solution to running editors via ssuuddoo. Due to the large number of programs that offer shell escapes, restricting users to the set of programs that do not is often unworkable. noexec Many systems that support shared libraries have the ability to override default library functions by pointing an environment variable (usually LD_PRELOAD) to an alternate shared library. On such systems, ssuuddoo's _n_o_e_x_e_c functionality can be used to prevent a program run by ssuuddoo from executing any other programs. Note, however, that this applies only to native dynamically-linked executables. Statically-linked executables and foreign executables running under binary emulation are not affected. The _n_o_e_x_e_c feature is known to work on SunOS, Solaris, *BSD, Linux, IRIX, Tru64 UNIX, MacOS X, HP-UX 11.x and AIX 5.3 and above. It should be supported on most operating systems that support the LD_PRELOAD environment variable. Check your operating system's manual pages for the dynamic linker (usually ld.so, ld.so.1, dyld, dld.sl, rld, or loader) to see if LD_PRELOAD is supported. On Solaris 10 and higher, _n_o_e_x_e_c uses Solaris privileges instead of the LD_PRELOAD environment variable. To enable _n_o_e_x_e_c for a command, use the NOEXEC tag as documented in the User Specification section above. Here is that example again: aaron shanty = NOEXEC: /usr/bin/more, /usr/bin/vi This allows user aaaarroonn to run _/_u_s_r_/_b_i_n_/_m_o_r_e and _/_u_s_r_/_b_i_n_/_v_i with _n_o_e_x_e_c enabled. This will prevent those two commands from executing other commands (such as a shell). If you are unsure whether or not your system is capable of supporting _n_o_e_x_e_c you can always just try it out and check whether shell escapes work when _n_o_e_x_e_c is enabled. Note that restricting shell escapes is not a panacea. Programs running as root are still capable of many potentially hazardous operations (such as changing or overwriting files) that could lead to unintended privilege escalation. In the specific case of an editor, a safer approach is to give the user permission to run ssuuddooeeddiitt (see below). SSeeccuurree eeddiittiinngg The ssuuddooeerrss plugin includes ssuuddooeeddiitt support which allows users to securely edit files with the editor of their choice. As ssuuddooeeddiitt is a built-in command, it must be specified in the _s_u_d_o_e_r_s file without a leading path. However, it may take command line arguments just as a normal command does. Wildcards used in _s_u_d_o_e_d_i_t command line arguments are expected to be path names, so a forward slash (`/') will not be matched by a wildcard. Unlike other ssuuddoo commands, the editor is run with the permissions of the invoking user and with the environment unmodified. More information may be found in the description of the --ee option in sudo(1m). For example, to allow user operator to edit the ``message of the day'' file: operator sudoedit /etc/motd The operator user then runs ssuuddooeeddiitt as follows: $ sudoedit /etc/motd The editor will run as the operator user, not root, on a temporary copy of _/_e_t_c_/_m_o_t_d. After the file has been edited, _/_e_t_c_/_m_o_t_d will be updated with the contents of the temporary copy. Users should _n_e_v_e_r be granted ssuuddooeeddiitt permission to edit a file that resides in a directory the user has write access to, either directly or via a wildcard. If the user has write access to the directory it is possible to replace the legitimate file with a link to another file, allowing the editing of arbitrary files. To prevent this, starting with version 1.8.16, symbolic links will not be followed in writable directories and ssuuddooeeddiitt will refuse to edit a file located in a writable directory unless the _s_u_d_o_e_d_i_t___c_h_e_c_k_d_i_r option has been disabled or the invoking user is root. Additionally, in version 1.8.15 and higher, ssuuddooeeddiitt will refuse to open a symbolic link unless either the _s_u_d_o_e_d_i_t___f_o_l_l_o_w option is enabled or the _s_u_d_o_e_d_i_t command is prefixed with the FOLLOW tag in the _s_u_d_o_e_r_s file. TTiimmee ssttaammpp ffiillee cchheecckkss ssuuddooeerrss will check the ownership of its time stamp directory (_/_v_a_r_/_r_u_n_/_s_u_d_o_/_t_s 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. Older versions of ssuuddoo stored time stamp files in _/_t_m_p; this is no longer recommended as it may be possible for a user to create the time stamp themselves on systems that allow unprivileged users to change the ownership of files they create. While the time stamp directory _s_h_o_u_l_d be cleared at reboot time, not all systems contain a _/_v_a_r_/_r_u_n directory. To avoid potential problems, ssuuddooeerrss will ignore time stamp files that date from before the machine booted on systems where the boot time is available. Some systems with graphical desktop environments allow unprivileged users to change the system clock. Since ssuuddooeerrss relies on the system clock for time stamp validation, it may be possible on such systems for a user to run ssuuddoo for longer than _t_i_m_e_s_t_a_m_p___t_i_m_e_o_u_t by setting the clock back. To combat this, ssuuddooeerrss uses a monotonic clock (which never moves backwards) for its time stamps if the system supports it. ssuuddooeerrss 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 ssuuddooeerrss will log and complain. 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 record's time stamp is within 5 minutes (or whatever value the timeout is set to in the _s_u_d_o_e_r_s file). When the _t_t_y___t_i_c_k_e_t_s option is enabled, the time stamp record includes the device number of the terminal the user authenticated with. This provides per- tty granularity but time stamp records still may outlive the user's session. The time stamp record also includes the session ID of the process that last authenticated. This prevents processes in different terminal sessions from using the same time stamp record. It also helps reduce the chance that a user will be able to run ssuuddoo without entering a password when logging out and back in again on the same terminal. DDEEBBUUGGGGIINNGG Versions 1.8.4 and higher of the ssuuddooeerrss plugin support a flexible debugging framework that can help track down what the plugin is doing internally if there is a problem. This can be configured in the sudo.conf(4) file. The ssuuddooeerrss plugin uses the same debug flag format as the ssuuddoo front-end: _s_u_b_s_y_s_t_e_m@_p_r_i_o_r_i_t_y. The priorities used by ssuuddooeerrss, in order of decreasing severity, are: _c_r_i_t, _e_r_r, _w_a_r_n, _n_o_t_i_c_e, _d_i_a_g, _i_n_f_o, _t_r_a_c_e and _d_e_b_u_g. Each priority, when specified, also includes all priorities higher than it. For example, a priority of _n_o_t_i_c_e would include debug messages logged at _n_o_t_i_c_e and higher. The following subsystems are used by the ssuuddooeerrss plugin: _a_l_i_a_s User_Alias, Runas_Alias, Host_Alias and Cmnd_Alias processing _a_l_l matches every subsystem _a_u_d_i_t BSM and Linux audit code _a_u_t_h user authentication _d_e_f_a_u_l_t_s _s_u_d_o_e_r_s file _D_e_f_a_u_l_t_s settings _e_n_v environment handling _l_d_a_p LDAP-based sudoers _l_o_g_g_i_n_g logging support _m_a_t_c_h matching of users, groups, hosts and netgroups in the _s_u_d_o_e_r_s file _n_e_t_i_f network interface handling _n_s_s network service switch handling in ssuuddooeerrss _p_a_r_s_e_r _s_u_d_o_e_r_s file parsing _p_e_r_m_s permission setting _p_l_u_g_i_n The equivalent of _m_a_i_n for the plugin. _p_t_y pseudo-tty related code _r_b_t_r_e_e redblack tree internals _s_s_s_d SSSD-based sudoers _u_t_i_l utility functions For example: Debug sudo /var/log/sudo_debug match@info,nss@info For more information, see the sudo.conf(4) manual. SSEEEE AALLSSOO ssh(1), su(1), fnmatch(3), glob(3), mktemp(3), strftime(3), sudo.conf(4), sudoers.ldap(4), sudo(1m), sudo_plugin(1m), visudo(1m) 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 (https://www.sudo.ws/contributors.html) for an exhaustive list of people who have contributed to ssuuddoo. CCAAVVEEAATTSS The _s_u_d_o_e_r_s file should aallwwaayyss be edited by the vviissuuddoo command which locks the file and does grammatical checking. It is imperative that the _s_u_d_o_e_r_s file be free of syntax errors since ssuuddoo will not run with a syntactically incorrect _s_u_d_o_e_r_s file. When using netgroups of machines (as opposed to users), if you store fully qualified host name in the netgroup (as is usually the case), you either need to have the machine's host name be fully qualified as returned by the hostname command or use the _f_q_d_n option in _s_u_d_o_e_r_s. BBUUGGSS If you feel you have found a bug in ssuuddoo, please submit a bug report at https://bugzilla.sudo.ws/ SSUUPPPPOORRTT Limited free support is available via the sudo-users mailing list, see https://www.sudo.ws/mailman/listinfo/sudo-users to subscribe or search the archives. 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 https://www.sudo.ws/license.html for complete details. Sudo 1.8.17 January 20, 2016 Sudo 1.8.17