sudoers(5) — Linux manual page

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SUDOERS(5)                 BSD File Formats Manual                SUDOERS(5)

NAME         top

     sudoers — default sudo security policy plugin

DESCRIPTION         top

     The sudoers policy plugin determines a user's sudo privileges.  It is
     the default sudo policy plugin.  The policy is driven by the
     /etc/sudoers file or, optionally in LDAP.  The policy format is
     described in detail in the SUDOERS FILE FORMAT section.  For informa‐
     tion on storing sudoers policy information in LDAP, please see
     sudoers.ldap(5).

   Configuring sudo.conf for sudoers
     sudo consults the sudo.conf(5) file to determine which policy and I/O
     logging plugins to load.  If no sudo.conf(5) file is present, or if it
     contains no Plugin lines, sudoers will be used for policy decisions and
     I/O logging.  To explicitly configure sudo.conf(5) to use the sudoers
     plugin, the following configuration can be used.

           Plugin sudoers_policy sudoers.so
           Plugin sudoers_io sudoers.so

     Starting with sudo 1.8.5, it is possible to specify optional arguments
     to the sudoers plugin in the sudo.conf(5) file.  These arguments, if
     present, should be listed after the path to the plugin (i.e., after
     sudoers.so).  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 ldap_conf argument can be used to override the default
               path to the ldap.conf file.

     ldap_secret=pathname
               The ldap_secret argument can be used to override the default
               path to the ldap.secret file.

     sudoers_file=pathname
               The sudoers_file argument can be used to override the default
               path to the sudoers file.

     sudoers_uid=uid
               The sudoers_uid 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 sudoers_gid 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 sudoers_mode 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(5), please refer to its
     manual.

   User Authentication
     The sudoers security policy requires that most users authenticate them‐
     selves before they can use sudo.  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 com‐
     mand.  Unlike su(1), when sudoers requires authentication, it validates
     the invoking user's credentials, not the target user's (or root's) cre‐
     dentials.  This can be changed via the rootpw, targetpw and runaspw
     flags, described later.

     If a user who is not listed in the policy tries to run a command via
     sudo, mail is sent to the proper authorities.  The address used for
     such mail is configurable via the mailto Defaults entry (described
     later) and defaults to root.

     Note that no mail will be sent if an unauthorized user tries to run
     sudo with the -l or -v option unless there is an authentication error
     and either the mail_always or mail_badpass flags are enabled.  This
     allows users to determine for themselves whether or not they are
     allowed to use sudo.  By default, all attempts to run sudo (successful
     or not) are logged, regardless of whether or not mail is sent.

     If sudo is run by root and the SUDO_USER environment variable is set,
     the sudoers 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 -e option to remain
     useful even when invoked via a sudo-run script or program.  Note, how‐
     ever, that the sudoers file lookup is still done for root, not the user
     specified by SUDO_USER.

     sudoers uses per-user time stamp files for credential caching.  Once a
     user has been authenticated, a record is written containing the user-ID
     that was used to authenticate, the terminal session ID, the start time
     of the session leader (or parent process) and a time stamp (using a
     monotonic clock if one is available).  The user may then use sudo with‐
     out a password for a short period of time (5 minutes unless overridden
     by the timestamp_timeout option).  By default, sudoers uses a separate
     record for each terminal, which means that a user's login sessions are
     authenticated separately.  The timestamp_type option can be used to
     select the type of time stamp record sudoers will use.

   Logging
     By default, sudoers logs both successful and unsuccessful attempts (as
     well as errors).  The log_allowed and log_denied flags can be used to
     control this behavior.  Messages can be logged to syslog(3), a log
     file, or both.  The default is to log to syslog(3) but this is config‐
     urable via the syslog and logfile settings.  See LOG FORMAT for a
     description of the log file format.

     sudoers is also capable of running a command in a pseudo-terminal and
     logging all input and/or output.  The standard input, standard output
     and standard error can be logged even when not associated with a termi‐
     nal.  I/O logging is not on by default but can be enabled using the
     log_input and log_output options as well as the LOG_INPUT and
     LOG_OUTPUT command tags.  See I/O LOG FILES for details on how I/O log
     files are stored.

   Command environment
     Since environment variables can influence program behavior, sudoers
     provides a means to restrict which variables from the user's environ‐
     ment are inherited by the command to be run.  There are two distinct
     ways sudoers can deal with environment variables.

     By default, the env_reset flag 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
     /etc/environment file.  The HOME, MAIL, SHELL, LOGNAME and USER envi‐
     ronment variables are initialized based on the target user and the
     SUDO_* variables are set based on the invoking user.  Additional vari‐
     ables, such as DISPLAY, PATH and TERM, are preserved from the invoking
     user's environment if permitted by the env_check or env_keep options.
     This is effectively a whitelist for environment variables.  A few envi‐
     ronment variables are treated specially.  If the PATH and TERM vari‐
     ables are not preserved from the user's environment, they will be set
     to default values.  The LOGNAME and USER are handled as a single
     entity.  If one of them is preserved (or removed) from the user's envi‐
     ronment, the other will be as well.  If LOGNAME and USER are to be pre‐
     served but only one of them is present in the user's environment, the
     other will be set to the same value.  This avoids an inconsistent envi‐
     ronment where one of the variables describing the user name is set to
     the invoking user and one is set to the target user.  Environment vari‐
     ables with a value beginning with () are removed unless both the name
     and value parts are matched by env_keep or env_check, as they may be
     interpreted as functions by the bash shell.  Prior to version 1.8.11,
     such variables were always removed.

     If, however, the env_reset flag is disabled, any variables not explic‐
     itly denied by the env_check and env_delete options are inherited from
     the invoking process.  In this case, env_check and env_delete behave
     like a blacklist.  Prior to version 1.8.21, environment variables with
     a value beginning with () were always removed.  Beginning with version
     1.8.21, a pattern in env_delete is used to match bash shell functions
     instead.  Since it is not possible to blacklist all potentially danger‐
     ous environment variables, use of the default env_reset behavior is
     encouraged.

     Environment variables specified by env_check, env_delete, or env_keep
     may include one or more ‘*’ characters which will match zero or more
     characters.  No other wildcard characters are supported.

     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, a bash shell function could be matched as
     follows:

         env_keep += "BASH_FUNC_my_func%%=()*"

     Without the “=()*” suffix, this would not match, as bash shell func‐
     tions are not preserved by default.

     The complete list of environment variables that are preserved or
     removed, as modified by global Defaults parameters in sudoers, is dis‐
     played when sudo is run by root with the -V option.  Please note that
     the list of environment variables to remove varies based on the operat‐
     ing system sudo is running on.

     Other sudoers options may influence the command environment, such as
     always_set_home, secure_path, set_logname, and set_home.

     On systems that support PAM where the pam_env module is enabled for
     sudo, variables in the PAM environment may be merged in to the environ‐
     ment.  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 sudoers.  When env_reset is enabled, variables
     preserved from the invoking user's environment by the env_keep list
     take precedence over those in the PAM environment.  When env_reset is
     disabled, variables present the invoking user's environment take prece‐
     dence over those in the PAM environment unless they match a pattern in
     the env_delete list.

     Note that the dynamic linker on most operating systems will remove
     variables that can control dynamic linking from the environment of set-
     user-ID executables, including sudo.  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 sudo even begins execution and, as such, it is not possible for
     sudo to preserve them.

     As a special case, if the -i option (initial login) is specified,
     sudoers will initialize the environment regardless of the value of
     env_reset.  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
     /etc/environment are also included.  All other environment variables
     are removed unless permitted by env_keep or env_check, described above.

     Finally, the restricted_env_file and env_file files are applied, if
     present.  The variables in restricted_env_file are applied first and
     are subject to the same restrictions as the invoking user's environ‐
     ment, as detailed above.  The variables in env_file are applied last
     and are not subject to these restrictions.  In both cases, variables
     present in the files will only be set to their specified values if they
     would not conflict with an existing environment variable.

SUDOERS FILE FORMAT         top

     The sudoers file is composed of two types of entries: aliases (basi‐
     cally 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 sudoers 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.

   Quick guide to EBNF
     EBNF is a concise and exact way of describing the grammar of a lan‐
     guage.  Each EBNF definition is made up of production rules.  E.g.,

     symbol ::= definition | alternate1 | alternate2 ...

     Each production rule 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, con‐
     fuse 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).

   Aliases
     There are four kinds of aliases: User_Alias, Runas_Alias, Host_Alias
     and Cmnd_Alias.  Beginning with sudo 1.9.0, Cmd_Alias may be used in
     place of Cmnd_Alias if desired.

     Alias ::= 'User_Alias'  User_Alias_Spec (':' User_Alias_Spec)* |
               'Runas_Alias' Runas_Alias_Spec (':' Runas_Alias_Spec)* |
               'Host_Alias'  Host_Alias_Spec (':' Host_Alias_Spec)* |
               'Cmnd_Alias'  Cmnd_Alias_Spec (':' Cmnd_Alias_Spec)* |
               'Cmd_Alias'   Cmnd_Alias_Spec (':' Cmnd_Alias_Spec)*

     User_Alias ::= NAME

     User_Alias_Spec ::= User_Alias '=' User_List

     Runas_Alias ::= NAME

     Runas_Alias_Spec ::= Runas_Alias '=' Runas_List

     Host_Alias ::= NAME

     Host_Alias_Spec ::= Host_Alias '=' Host_List

     Cmnd_Alias ::= NAME

     Cmnd_Alias_Spec ::= Cmnd_Alias '=' Cmnd_List

     NAME ::= [A-Z]([A-Z][0-9]_)*

     Each alias definition is of the form

     Alias_Type NAME = item1, item2, ...

     where Alias_Type 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 must start with an uppercase let‐
     ter.  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 alias.  It is possible to
     use the same name for aliases of different types, but this is not rec‐
     ommended.

     The definitions of what constitutes a valid alias 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 num‐
     ber 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 underly‐
     ing group provider plugin.  For instance, the QAS AD plugin supports
     the following formats:

     ·  Group in the same domain: "%:Group Name"

     ·  Group in any domain: "%:Group Name@FULLY.QUALIFIED.DOMAIN"

     ·  Group SID: "%:S-1-2-34-5678901234-5678901234-5678901234-567"

     See GROUP PROVIDER PLUGINS for more information.

     Note that quotes around group names are optional.  Unquoted strings
     must use a backslash (‘\’) to escape spaces and special characters.
     See Other special characters and reserved words for a list of charac‐
     ters 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 user (group) ID are considered to be distinct.  If you wish to
     match all user names with the same user-ID (e.g., root and toor), you
     can use a user-ID instead of a name (#0 in the example given).  Note
     that the user-ID or group-ID specified in a Runas_Member need not be
     listed in the password or group database.

     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 spec‐
     ify a network number without a netmask, sudo 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 nota‐
     tion (number of bits, e.g., 24 or 64).  A host name may include shell-
     style wildcards (see the Wildcards section below), but unless the host
     name command on your machine returns the fully qualified host name,
     you'll need to use the fqdn flag for wildcards to be useful.  Note that
     sudo 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

     Digest_List ::= Digest_Spec |
                     Digest_Spec ',' Digest_List

     Cmnd_List ::= Cmnd |
                   Cmnd ',' Cmnd_List

     command name ::= file name |
                      file name args |
                      file name '""'

     Edit_Spec ::= "sudoedit" file name+

     Cmnd ::= Digest_List? '!'* command name |
              '!'* directory |
              '!'* Edit_Spec |
              '!'* 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 Wildcards section below).  A
     simple file name allows the user to run the command with any arguments
     they wish.  However, you may also specify command line arguments
     (including wildcards).  Alternately, you can specify "" to indicate
     that the command may only be run without 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 argu‐
     ments: ‘,’, ‘:’, ‘=’, ‘\’.  The built-in command “sudoedit” is used to
     permit a user to run sudo with the -e option (or as sudoedit).  It may
     take command line arguments just as a normal command does.  Note that
     “sudoedit” is a command built into sudo itself and must be specified in
     the sudoers file without a leading path.  If a leading path is present,
     for example /usr/bin/sudoedit, the path name will be silently converted
     to “sudoedit”.  A fully-qualified path for sudoedit is treated as an
     error by visudo.

     A command name may be preceded by a Digest_List, a comma-separated list
     of one or more Digest_Spec entries.  If a Digest_List is present, the
     command will only match successfully if it can be verified using one of
     the SHA-2 digests in the list.  Starting with version 1.9.0, the ALL
     reserved word can be used in conjunction with a Digest_List.  The fol‐
     lowing 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 sudo command), it may be possible for the user to replace the
     command after the digest check has been performed but before the com‐
     mand 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.  See the description of the fdexec
     setting for more information on how sudo executes commands that have an
     associated digest.

     Command digests are only supported by version 1.8.7 or higher.

   Defaults
     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 flags, integer values, strings, or lists.  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 con‐
     text 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 oper‐
     ators 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, user
     and runas Defaults first, then command defaults.  If there are multiple
     Defaults settings of the same type, the last matching setting is used.
     The following Defaults settings are parsed before all others since they
     may affect subsequent entries: fqdn, group_plugin, runas_default,
     sudoers_locale.

     See SUDOERS OPTIONS for a list of supported Defaults parameters.

   User specification
     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? Option_Spec* Tag_Spec* Cmnd

     Runas_Spec ::= '(' Runas_List? (':' Runas_List)? ')'

     Option_Spec ::= (Date_Spec | Timeout_Spec)

     Date_Spec ::= ('NOTBEFORE=timestamp' | 'NOTAFTER=timestamp')

     Timeout_Spec ::= 'TIMEOUT=timeout'

     Tag_Spec ::= ('EXEC:' | 'NOEXEC:' | 'FOLLOW:' | 'NOFOLLOW' |
                   'LOG_INPUT:' | 'NOLOG_INPUT:' | 'LOG_OUTPUT:' |
                   'NOLOG_OUTPUT:' | 'MAIL:' | 'NOMAIL:' | 'PASSWD:' |
                   'NOPASSWD:' | 'SETENV:' | 'NOSETENV:')

     A user specification determines which commands a user may run (and as
     what user) on specified hosts.  By default, commands are run as root,
     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:

   Runas_Spec
     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 the -u option.  The second defines a list of groups
     that can be specified via the -g option in addition to any of the tar‐
     get user's groups.  If both Runas_Lists are specified, the command may
     be run with any combination of users and groups listed in their respec‐
     tive Runas_Lists. If only the first is specified, the command may be
     run as any user in the list but no -g 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 root 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 dgb may run /bin/ls, /bin/kill, and /usr/bin/lprm on the host
     boulder—but only as operator.  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 dgb is now allowed to run /bin/ls as operator, but /bin/kill
     and /usr/bin/lprm as root.

     We can extend this to allow dgb to run /bin/ls with either the user or
     group set to operator:

     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 tcm 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 tcm.  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 -u and
     -g options.  In this example:

     alan    ALL = (root, bin : operator, system) ALL

     user alan may run any command as either user root or bin, optionally
     setting the group to operator or system.

   Option_Spec
     A Cmnd may have zero or more options associated with it.  Options may
     consist of start and/or end dates and command timeouts.  Once an option
     is set for a Cmnd, subsequent Cmnds in the Cmnd_Spec_List, inherit that
     option unless it is overridden by another option.

   Date_Spec
     sudoers rules can be specified with a start and end date via the
     NOTBEFORE and NOTAFTER settings.  The time stamp must be specified in
     Generalized Time as defined by RFC 4517.  The format is effectively
     yyyymmddHHMMSSZ where the minutes and seconds are optional.  The ‘Z’
     suffix indicates that the time stamp is in Coordinated Universal Time
     (UTC).  It is also possible to specify a timezone offset from UTC in
     hours and minutes instead of a ‘Z’.  For example, ‘-0500’ would corre‐
     spond to Eastern Standard time in the US.  As an extension, if no ‘Z’
     or timezone offset is specified, local time will be used.

     The following are all valid time stamps:

         20170214083000Z
         2017021408Z
         20160315220000-0500
         20151201235900

   Timeout_Spec
     A command may have a timeout associated with it.  If the timeout
     expires before the command has exited, the command will be terminated.
     The timeout may be specified in combinations of days, hours, minutes
     and seconds with a single-letter case-insensitive suffix that indicates
     the unit of time.  For example, a timeout of 7 days, 8 hours, 30 min‐
     utes and 10 seconds would be written as 7d8h30m10s.  If a number is
     specified without a unit, seconds are assumed.  Any of the days, min‐
     utes, hours or seconds may be omitted.  The order must be from largest
     to smallest unit and a unit may not be specified more than once.

     The following are all valid timeout values: 7d8h30m10s, 14d, 8h30m,
     600s, 3600.  The following are invalid timeout values: 12m2w1d,
     30s10m4h, 1d2d3h.

     This setting is only supported by version 1.8.20 or higher.

   Tag_Spec
     A command may have zero or more tags associated with it.  The following
     tag values are supported: 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).

     EXEC and NOEXEC

       If sudo has been compiled with noexec 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 aaron may run /usr/bin/more and
       /usr/bin/vi but shell escapes will be disabled.

       aaron   shanty = NOEXEC: /usr/bin/more, /usr/bin/vi

       See the Preventing shell escapes section below for more details on
       how NOEXEC works and whether or not it will work on your system.

     FOLLOW and NOFOLLOW Starting with version 1.8.15, sudoedit will not
       open a file that is a symbolic link unless the sudoedit_follow flag
       is enabled.  The FOLLOW and NOFOLLOW tags override the value of
       sudoedit_follow 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 sudoedit command and are ignored for all other commands.

     LOG_INPUT and NOLOG_INPUT

       These tags override the value of the log_input flag on a per-command
       basis.  For more information, see the description of log_input in the
       SUDOERS OPTIONS section below.

     LOG_OUTPUT and NOLOG_OUTPUT

       These tags override the value of the log_output flag on a per-command
       basis.  For more information, see the description of log_output in
       the SUDOERS OPTIONS section below.

     MAIL and NOMAIL

       These tags provide fine-grained control over whether mail will be
       sent when a user runs a command by overriding the value of the
       mail_all_cmnds flag on a per-command basis.  They have no effect when
       sudo is run with the -l or -v options.  A NOMAIL tag will also over‐
       ride the mail_always and mail_no_perms options.  For more informa‐
       tion, see the descriptions of mail_all_cmnds, mail_always, and
       mail_no_perms in the SUDOERS OPTIONS section below.

     PASSWD and NOPASSWD

       By default, sudo 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 ray to run /bin/kill, /bin/ls, and /usr/bin/lprm
       as root on the machine rushmore without authenticating himself.  If
       we only want ray to be able to run /bin/kill 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 exempt_group setting.

       By default, if the NOPASSWD tag is applied to any of a user's entries
       for the current host, the user will be able to run “sudo -l” without
       a password.  Additionally, a user may only run “sudo -v” without a
       password if all of the user's entries for the current host have the
       NOPASSWD tag.  This behavior may be overridden via the verifypw and
       listpw options.

     SETENV and NOSETENV

       These tags override the value of the setenv flag on a per-command
       basis.  Note that if SETENV has been set for a command, the user may
       disable the env_reset flag from the command line via the -E option.
       Additionally, environment variables set on the command line are not
       subject to the restrictions imposed by env_check, env_delete, or
       env_keep.  As such, only trusted users should be allowed to set vari‐
       ables in this manner.  If the command matched is ALL, the SETENV tag
       is implied for that command; this default may be overridden by use of
       the NOSETENV tag.

   Wildcards
     sudo allows shell-style wildcards (aka meta or glob characters) to be
     used in host names, path names and command line arguments in the
     sudoers 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 not in the specified range.

     \x        For any character ‘x’, evaluates to ‘x’.  This is used to
               escape special characters such as: ‘*’, ‘?’, ‘[’, and ‘]’.

     Note that these are not regular expressions.  Unlike a regular expres‐
     sion 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 sudoers, it must be escaped.  For example:

         /bin/ls [[\:alpha\:]]*

     Would match any file name beginning with a letter.

     Note that a forward slash (‘/’) will not be matched by wildcards used
     in the file name portion of the command.  This is to make a path like:

         /usr/bin/*

     match /usr/bin/who but not /usr/bin/X11/xterm.

     When matching the command line arguments, however, a slash does get
     matched by wildcards since command line arguments may contain arbitrary
     strings and not just path names.

     Wildcards in command line arguments should be used with care.
     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 sudoers file in a scripting
     language.

   Exceptions to wildcard rules
     The following exceptions apply to the above rules:

     ""        If the empty string "" is the only command line argument in
               the sudoers file entry it means that command is not allowed
               to be run with any arguments.

     sudoedit  Command line arguments to the sudoedit built-in command
               should always be path names, so a forward slash (‘/’) will
               not be matched by a wildcard.

   Including other files from within sudoers
     It is possible to include other sudoers files from within the sudoers
     file currently being parsed using the @include and @includedir direc‐
     tives.  For compatibility with sudo versions prior to 1.9.1, #include
     and #includedir are also accepted.

     An include file can be used, for example, to keep a site-wide sudoers
     file in addition to a local, per-machine file.  For the sake of this
     example the site-wide sudoers file will be /etc/sudoers and the per-
     machine one will be /etc/sudoers.local.  To include /etc/sudoers.local
     from within /etc/sudoers one would use the following line in
     /etc/sudoers:

         @include /etc/sudoers.local

     When sudo reaches this line it will suspend processing of the current
     file (/etc/sudoers) and switch to /etc/sudoers.local.  Upon reaching
     the end of /etc/sudoers.local, the rest of /etc/sudoers will be pro‐
     cessed.  Files that are included may themselves include other files.  A
     hard limit of 128 nested include files is enforced to prevent include
     file loops.

     The path to the include file may contain white space if it is escaped
     with a backslash (‘\’).  Alternately, the entire path may be enclosed
     in double quotes (""), in which case no escaping is necessary.  To
     include a literal backslash in the path, ‘\\’ should be used.

     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 /etc/sudoers contains the
     line:

         @include sudoers.local

     the file that will be included is /etc/sudoers.local.

     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 sudo to include the file /etc/sudoers.xerxes.

     The @includedir directive can be used to create a sudoers.d directory
     that the system package manager can drop sudoers file rules into as
     part of package installation.  For example, given:

         @includedir /etc/sudoers.d

     sudo will suspend processing of the current file and read each file in
     /etc/sudoers.d, skipping file names that end in ‘~’ or contain a ‘.’
     character to avoid causing problems with package manager or editor tem‐
     porary/backup files.  Files are parsed in sorted lexical order.  That
     is, /etc/sudoers.d/01_first will be parsed before
     /etc/sudoers.d/10_second.  Be aware that because the sorting is lexi‐
     cal, not numeric, /etc/sudoers.d/1_whoops would be loaded after
     /etc/sudoers.d/10_second.  Using a consistent number of leading zeroes
     in the file names can be used to avoid such problems.  After parsing
     the files in the directory, control returns to the file that contained
     the @includedir directive.

     Note that unlike files included via @include, visudo will not edit the
     files in a @includedir directory unless one of them contains a syntax
     error.  It is still possible to run visudo with the -f flag to edit the
     files directly, but this will not catch the redefinition of an alias
     that is also present in a different file.

   Other special characters and reserved words
     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 user-ID).  Both the comment character and any text after it, up to
     the end of the line, are ignored.

     The reserved word ALL is a built-in alias 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 alias called ALL as the built-in alias will be used in prefer‐
     ence to your own.  Please note that using ALL can be dangerous since in
     a command context, it allows the user to run any command on the system.

     An exclamation point (‘!’) can be used as a logical not operator in a
     list or alias 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 ALL, 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 ALL
     alias to allow a user to run “all but a few” commands rarely works as
     intended (see SECURITY NOTES below).

     Long lines can be continued with a backslash (‘\’) as the last charac‐
     ter on the line.

     White space between elements in a list as well as special syntactic
     characters in a User Specification (‘=’, ‘:’, ‘(’, ‘)’) 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): ‘!’, ‘=’, ‘:’,
     ‘,’, ‘(’, ‘)’, ‘\’.

SUDOERS OPTIONS         top

     sudo'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.

     Boolean Flags:

     always_query_group_plugin
                       If a group_plugin 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
                       group_plugin.  This flag is off by default.

     always_set_home   If enabled, sudo will set the HOME environment vari‐
                       able to the home directory of the target user (which
                       is the root user unless the -u option is used).  This
                       flag is largely obsolete and has no effect unless the
                       env_reset flag has been disabled or HOME is present
                       in the env_keep list, both of which are strongly dis‐
                       couraged.  This flag is off 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 overrid‐
                       den via the PASSWD and NOPASSWD tags.  This flag is
                       on by default.

     case_insensitive_group
                       If enabled, group names in sudoers will be matched in
                       a case insensitive manner.  This may be necessary
                       when users are stored in LDAP or AD.  This flag is on
                       by default.

     case_insensitive_user
                       If enabled, user names in sudoers will be matched in
                       a case insensitive manner.  This may be necessary
                       when groups are stored in LDAP or AD.  This flag is
                       on by default.

     closefrom_override
                       If set, the user may use the -C option which over‐
                       rides the default starting point at which sudo begins
                       closing open file descriptors.  This flag is off by
                       default.

     compress_io       If set, and sudo is configured to log a command's
                       input or output, the I/O logs will be compressed
                       using zlib.  This flag is on by default when sudo is
                       compiled with zlib support.

     exec_background   By default, sudo runs a command as the foreground
                       process as long as sudo itself is running in the
                       foreground.  When the exec_background flag is enabled
                       and the command is being run in a pseudo-terminal
                       (due to I/O logging or the use_pty flag), the command
                       will be run as a background process.  Attempts to
                       read from the controlling terminal (or to change ter‐
                       minal settings) will result in the command being sus‐
                       pended with the SIGTTIN signal (or SIGTTOU in the
                       case of terminal settings).  If this happens when
                       sudo 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 sudo need not read from the termi‐
                       nal unless the command explicitly requests it.  Oth‐
                       erwise, any terminal input must be passed to the com‐
                       mand, 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 sudo behavior or when the
                       command is not being run in a pseudo-terminal.

                       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, macOS fails to restart the
                       tcgetattr() and tcsetattr() system calls (this is a
                       bug in macOS).  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 (usu‐
                       ally SIGTOP) will not be automatically foregrounded.
                       Some versions of the linux su(1) command behave this
                       way.  This flag is off 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 use_pty flag is enabled.

     env_editor        If set, visudo will use the value of the SUDO_EDITOR,
                       VISUAL or EDITOR environment variables before falling
                       back on the default editor list.  Note that visudo is
                       typically run as root so this flag may allow a user
                       with visudo privileges to run arbitrary commands as
                       root without logging.  An alternative is to place a
                       colon-separated list of “safe” editors int the editor
                       variable.  visudo will then only use SUDO_EDITOR,
                       VISUAL or EDITOR if they match a value specified in
                       editor.  If the env_reset flag is enabled, the
                       SUDO_EDITOR, VISUAL and/or EDITOR environment vari‐
                       ables must be present in the env_keep list for the
                       env_editor flag to function when visudo is invoked
                       via sudo.  This flag is on by default.

     env_reset         If set, sudo will run the command in a minimal envi‐
                       ronment containing the TERM, PATH, HOME, MAIL, SHELL,
                       LOGNAME, USER and SUDO_* variables.  Any variables in
                       the caller's environment or in the file specified by
                       the restricted_env_file setting that match the
                       env_keep and env_check lists are then added, followed
                       by any variables present in the file specified by the
                       env_file setting (if any).  The contents of the
                       env_keep and env_check lists, as modified by global
                       Defaults parameters in sudoers, are displayed when
                       sudo is run by root with the -V option.  If the
                       secure_path setting is enabled, its value will be
                       used for the PATH environment variable.  This flag is
                       on by default.

     fast_glob         Normally, sudo 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
                       fast_glob flag causes sudo to use the fnmatch(3)
                       function, which does not access the file system to do
                       its matching.  The disadvantage of fast_glob is that
                       it is unable to match relative path names such as
                       ./ls or ../bin/ls.  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 flag should
                       not be used when the sudoers file contains rules that
                       contain negated path names which include globbing
                       characters.  This flag is off by default.

     fqdn              Set this flag if you want to put fully qualified host
                       names in the sudoers file when the local host name
                       (as returned by the hostname command) does not con‐
                       tain 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 flag is only effective when the
                       “canonical” host name, as returned by the
                       getaddrinfo() or gethostbyname() 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 /etc/hosts
                       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 spec‐
                       ified in the /etc/nsswitch.conf, /etc/netsvc.conf,
                       /etc/host.conf, or, in some cases, /etc/resolv.conf
                       file.  In the /etc/hosts file, the first host name of
                       the entry is considered to be the “canonical” name;
                       subsequent names are aliases that are not used by
                       sudoers.  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 fqdn flag will not be effective if it
                       is queried before DNS.

                       Beware that when using DNS for host name resolution,
                       turning on fqdn requires sudoers to make DNS lookups
                       which renders sudo unusable if DNS stops working (for
                       example if the machine is disconnected from the net‐
                       work).  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 off by default.

     ignore_audit_errors
                       Allow commands to be run even if sudoers cannot write
                       to the audit log.  If enabled, an audit log write
                       failure is not treated as a fatal error.  If dis‐
                       abled, a command may only be run after the audit
                       event is successfully written.  This flag is only
                       effective on systems for which sudoers supports audit
                       logging, including FreeBSD, Linux, macOS and Solaris.
                       This flag is on by default.

     ignore_dot        If set, sudo will ignore "." or "" (both denoting
                       current directory) in the PATH environment variable;
                       the PATH itself is not modified.  This flag is off by
                       default.

     ignore_iolog_errors
                       Allow commands to be run even if sudoers cannot write
                       to the I/O log (local or remote).  If enabled, an I/O
                       log write failure is not treated as a fatal error.
                       If disabled, the command will be terminated if the
                       I/O log cannot be written to.  This flag is off by
                       default.

     ignore_logfile_errors
                       Allow commands to be run even if sudoers cannot write
                       to the log file.  If enabled, a log file write fail‐
                       ure is not treated as a fatal error.  If disabled, a
                       command may only be run after the log file entry is
                       successfully written.  This flag only has an effect
                       when sudoers is configured to use file-based logging
                       via the logfile setting.  This flag is on by default.

     ignore_local_sudoers
                       If set via LDAP, parsing of /etc/sudoers 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
                       /etc/sudoers.  When this flag is enabled,
                       /etc/sudoers does not even need to exist.  Since this
                       flag tells sudo how to behave when no specific LDAP
                       entries have been matched, this sudoOption is only
                       meaningful for the cn=defaults section.  This flag is
                       off by default.

     ignore_unknown_defaults
                       If set, sudo will not produce a warning if it encoun‐
                       ters an unknown Defaults entry in the sudoers file or
                       an unknown sudoOption in LDAP.  This flag is off by
                       default.

     insults           If set, sudo will insult users when they enter an
                       incorrect password.  This flag is off by default.

     log_allowed       If set, sudoers will log commands allowed by the pol‐
                       icy to the system audit log (where supported) as well
                       as to syslog and/or a log file.  This flag is on by
                       default.

                       This setting is only supported by version 1.8.29 or
                       higher.

     log_denied        If set, sudoers will log commands denied by the pol‐
                       icy to the system audit log (where supported) as well
                       as to syslog and/or a log file.  This flag is on by
                       default.

                       This setting is only supported by version 1.8.29 or
                       higher.

     log_host          If set, the host name will be included in log entries
                       written to the file configured by the logfile set‐
                       ting.  This flag is off by default.

     log_input         If set, sudo will run the command in a pseudo-termi‐
                       nal and log all user input.  If the standard input is
                       not connected to the user's tty, due to I/O redirect‐
                       ion or because the command is part of a pipeline,
                       that input is also captured and stored in a separate
                       log file.  Anything sent to the standard input will
                       be consumed, regardless of whether or not the command
                       run via sudo is actually reading the standard input.
                       This may have unexpected results when using sudo in a
                       shell script that expects to process the standard
                       input.  For more information about I/O logging, see
                       the I/O LOG FILES section.  This flag is off by
                       default.

     log_output        If set, sudo will run the command in a pseudo-termi‐
                       nal and log all output that is sent to the screen,
                       similar to the script(1) command.  For more informa‐
                       tion about I/O logging, see the I/O LOG FILES sec‐
                       tion.  This flag is off by default.

     log_server_keepalive
                       If set, sudo will enable the TCP keepalive socket
                       option on the connection to the log server.  This
                       enables the periodic transmission of keepalive mes‐
                       sages to the server.  If the server does not respond
                       to a message, the connection will be closed and the
                       running command will be killed unless the
                       ignore_iolog_errors flag is set.  This flag is on by
                       default.

     log_server_verify
                       If set, the server certificate received during the
                       TLS handshake must be valid and it must contain
                       either the server name (from log_servers) or its IP
                       address.  If either of these conditions is not met,
                       the TLS handshake will fail.  This flag is on by
                       default.  sudo

     log_year          If set, the four-digit year will be logged in the
                       (non-syslog) sudo log file.  This flag is off by
                       default.

     long_otp_prompt   When validating with a One Time Password (OTP) scheme
                       such as S/Key or OPIE, 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
                       off by default.

     mail_all_cmnds    Send mail to the mailto user every time a user
                       attempts to run a command via sudo (this includes
                       sudoedit).  No mail will be sent if the user runs
                       sudo with the -l or -v option unless there is an
                       authentication error and the mail_badpass flag is
                       also set.  This flag is off by default.

     mail_always       Send mail to the mailto user every time a user runs
                       sudo.  This flag is off by default.

     mail_badpass      Send mail to the mailto user if the user running sudo
                       does not enter the correct password.  If the command
                       the user is attempting to run is not permitted by
                       sudoers and one of the mail_all_cmnds, mail_always,
                       mail_no_host, mail_no_perms or mail_no_user flags are
                       set, this flag will have no effect.  This flag is off
                       by default.

     mail_no_host      If set, mail will be sent to the mailto user if the
                       invoking user exists in the sudoers file, but is not
                       allowed to run commands on the current host.  This
                       flag is off by default.

     mail_no_perms     If set, mail will be sent to the mailto user if the
                       invoking user is allowed to use sudo but the command
                       they are trying is not listed in their sudoers file
                       entry or is explicitly denied.  This flag is off by
                       default.

     mail_no_user      If set, mail will be sent to the mailto user if the
                       invoking user is not in the sudoers file.  This flag
                       is on by default.

     match_group_by_gid
                       By default, sudoers will look up each group the user
                       is a member of by group-ID to determine the group
                       name (this is only done once).  The resulting list of
                       the user's group names is used when matching groups
                       listed in the sudoers file.  This works well on sys‐
                       tems where the number of groups listed in the sudoers
                       file is larger than the number of groups a typical
                       user belongs to.  On systems where group lookups are
                       slow, where users may belong to a large number of
                       groups, and where the number of groups listed in the
                       sudoers file is relatively small, it may be prohibi‐
                       tively expensive and running commands via sudo may
                       take longer than normal.  On such systems it may be
                       faster to use the match_group_by_gid flag to avoid
                       resolving the user's group-IDs to group names.  In
                       this case, sudoers must look up any group name listed
                       in the sudoers file and use the group-ID instead of
                       the group name when determining whether the user is a
                       member of the group.

                       Note that if match_group_by_gid is enabled, group
                       database lookups performed by sudoers will be keyed
                       by group name as opposed to group-ID.  On systems
                       where there are multiple sources for the group data‐
                       base, it is possible to have conflicting group names
                       or group-IDs in the local /etc/group file and the
                       remote group database.  On such systems, enabling or
                       disabling match_group_by_gid can be used to choose
                       whether group database queries are performed by name
                       (enabled) or ID (disabled), which may aid in working
                       around group entry conflicts.

                       The match_group_by_gid flag has no effect when
                       sudoers data is stored in LDAP.  This flag is off by
                       default.

                       This setting is only supported by version 1.8.18 or
                       higher.

     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, sudo 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 off
                       by default.

     noexec            If set, all commands run via sudo will behave as if
                       the NOEXEC tag has been set, unless overridden by an
                       EXEC tag.  See the description of EXEC and NOEXEC
                       above as well as the Preventing shell escapes section
                       at the end of this manual.  This flag is off by
                       default.

     pam_acct_mgmt     On systems that use PAM for authentication, sudo will
                       perform PAM account validation for the invoking user
                       by default.  The actual checks performed depend on
                       which PAM modules are configured.  If enabled,
                       account validation will be performed regardless of
                       whether or not a password is required.  This flag is
                       on by default.

                       This setting is only supported by version 1.8.28 or
                       higher.

     pam_rhost         On systems that use PAM for authentication, sudo will
                       set the PAM remote host value to the name of the
                       local host when the pam_rhost flag is enabled.  On
                       Linux systems, enabling pam_rhost may result in DNS
                       lookups of the local host name when PAM is initial‐
                       ized.  On Solaris versions prior to Solaris 8,
                       pam_rhost must be enabled if pam_ruser is also
                       enabled to avoid a crash in the Solaris PAM implemen‐
                       tation.

                       This flag is off by default on systems other than
                       Solaris.

                       This setting is only supported by version 1.9.0 or
                       higher.

     pam_ruser         On systems that use PAM for authentication, sudo will
                       set the PAM remote user value to the name of the user
                       that invoked sudo when the pam_ruser flag is enabled.
                       This flag is on by default.

                       This setting is only supported by version 1.9.0 or
                       higher.

     pam_session       On systems that use PAM for authentication, sudo will
                       create a new PAM session for the command to be run
                       in.  Unless sudo is given the -i or -s options, PAM
                       session modules are run with the “silent” flag
                       enabled.  This prevents last login information from
                       being displayed for every command on some systems.
                       Disabling pam_session 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
                       pam_session, pam_setcred, and use_pty are disabled
                       and I/O logging has not been configured, sudo will
                       execute the command directly instead of running it as
                       a child process.  This flag is on by default.

                       This setting is only supported by version 1.8.7 or
                       higher.

     pam_setcred       On systems that use PAM for authentication, sudo will
                       attempt to establish credentials for the target user
                       by default, if supported by the underlying authenti‐
                       cation system.  One example of a credential is a Ker‐
                       beros ticket.  If pam_session, pam_setcred, and
                       use_pty are disabled and I/O logging has not been
                       configured, sudo will execute the command directly
                       instead of running it as a child process.  This flag
                       is on by default.

                       This setting is only supported by version 1.8.8 or
                       higher.

     passprompt_override
                       If set, the prompt specified by passprompt or the
                       SUDO_PROMPT environment variable will always be used
                       and will replace the prompt provided by a PAM module
                       or other authentication method.  This flag is off by
                       default.

     path_info         Normally, sudo will tell the user when a command
                       could not be found in their PATH environment vari‐
                       able.  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 exe‐
                       cutable is simply not in the user's PATH, sudo will
                       tell the user that they are not allowed to run it,
                       which can be confusing.  This flag is on by default.

     preserve_groups   By default, sudo will initialize the group vector to
                       the list of groups the target user is in.  When
                       preserve_groups 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 off by default.

     pwfeedback        By default, sudo 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 sudo has
                       hung at this point.  When pwfeedback is set, sudo
                       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 off by
                       default.

     requiretty        If set, sudo will only run when the user is logged in
                       to a real tty.  When this flag is set, sudo can only
                       be run from a login session and not via other means
                       such as cron(8) or cgi-bin scripts.  This flag is off
                       by default.

     root_sudo         If set, root is allowed to run sudo too.  Disabling
                       this prevents users from “chaining” sudo commands to
                       get a root shell by doing something like “sudo sudo
                       /bin/sh”.  Note, however, that turning off root_sudo
                       will also prevent root from running sudoedit.  Dis‐
                       abling root_sudo provides no real additional secu‐
                       rity; it exists purely for historical reasons.  This
                       flag is on by default.

     rootpw            If set, sudo 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
                       off by default.

     runas_allow_unknown_id
                       If enabled, allow matching of runas user and group
                       IDs that are not present in the password or group
                       databases.  In addition to explicitly matching
                       unknown user or group IDs in a Runas_List, this
                       option also allows the ALL alias to match unknown
                       IDs.  This flag is off by default.

                       This setting is only supported by version 1.8.30 or
                       higher.  Older versions of sudo always allowed match‐
                       ing of unknown user and group IDs.

     runas_check_shell
                       If enabled, sudo will only run commands as a user
                       whose shell appears in the /etc/shells file, even if
                       the invoking user's Runas_List would otherwise permit
                       it.  If no /etc/shells file is present, a system-
                       dependent list of built-in default shells is used.
                       On many operating systems, system users such as
                       “bin”, do not have a valid shell and this flag can be
                       used to prevent commands from being run as those
                       users.  This flag is off by default.

                       This setting is only supported by version 1.8.30 or
                       higher.

     runaspw           If set, sudo will prompt for the password of the user
                       defined by the runas_default option (defaults to
                       root) instead of the password of the invoking user
                       when running a command or editing a file.  This flag
                       is off by default.

     set_home          If enabled and sudo is invoked with the -s option,
                       the HOME environment variable will be set to the home
                       directory of the target user (which is the root user
                       unless the -u option is used).  This flag is largely
                       obsolete and has no effect unless the env_reset flag
                       has been disabled or HOME is present in the env_keep
                       list, both of which are strongly discouraged.  This
                       flag is off by default.

     set_logname       Normally, sudo will set the LOGNAME and USER environ‐
                       ment variables to the name of the target user (usu‐
                       ally root unless the -u option is given).  However,
                       since some programs (including the RCS revision con‐
                       trol system) use LOGNAME to determine the real iden‐
                       tity of the user, it may be desirable to change this
                       behavior.  This can be done by negating the set_log‐
                       name option.  Note that set_logname will have no
                       effect if the env_reset option has not been disabled
                       and the env_keep list contains LOGNAME or USER.  This
                       flag is on by default.

     set_utmp          When enabled, sudo will create an entry in the utmp
                       (or utmpx) file when a pseudo-terminal is allocated.
                       A pseudo-terminal is allocated by sudo when it is
                       running in a terminal and one or more of the
                       log_input, log_output or use_pty flags is 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 on
                       by default.

     setenv            Allow the user to disable the env_reset option from
                       the command line via the -E option.  Additionally,
                       environment variables set via the command line are
                       not subject to the restrictions imposed by env_check,
                       env_delete, or env_keep.  As such, only trusted users
                       should be allowed to set variables in this manner.
                       This flag is off by default.

     shell_noargs      If set and sudo is invoked with no arguments it acts
                       as if the -s 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 off by default.

     stay_setuid       Normally, when sudo 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 sudo act as a set-user-ID
                       wrapper.  This can be useful on systems that disable
                       some potentially dangerous functionality when a pro‐
                       gram is run set-user-ID.  This option is only effec‐
                       tive on systems that support either the setreuid(2)
                       or setresuid(2) system call.  This flag is off by
                       default.

     sudoedit_checkdir
                       If set, sudoedit 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 sudoedit will refuse to
                       edit a file located in a writable directory.  These
                       restrictions are not enforced when sudoedit is run by
                       root.  On some systems, if all directory components
                       of the path to be edited are not readable by the tar‐
                       get user, sudoedit will be unable to edit the file.
                       This flag is on 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, sudoedit will not follow symbolic links
                       when opening files.  The sudoedit_follow option can
                       be enabled to allow sudoedit to open symbolic links.
                       It may be overridden on a per-command basis by the
                       FOLLOW and NOFOLLOW tags.  This flag is off by
                       default.

                       This setting is only supported by version 1.8.15 or
                       higher.

     syslog_pid        When logging via syslog(3), include the process ID in
                       the log entry.  This flag is off by default.

                       This setting is only supported by version 1.8.21 or
                       higher.

     targetpw          If set, sudo will prompt for the password of the user
                       specified by the -u option (defaults to root) instead
                       of the password of the invoking user when running a
                       command or editing a file.  Note that this flag pre‐
                       cludes the use of a user-ID not listed in the passwd
                       database as an argument to the -u option.  This flag
                       is off by default.

     tty_tickets       If set, users must authenticate on a per-tty basis.
                       With this flag enabled, sudo will use a separate
                       record in the time stamp file for each terminal.  If
                       disabled, a single record is used for all login ses‐
                       sions.

                       This option has been superseded by the timestamp_type
                       option.

     umask_override    If set, sudo will set the umask as specified in the
                       sudoers file without modification.  This makes it
                       possible to specify a umask in the sudoers file that
                       is more permissive than the user's own umask and
                       matches historical behavior.  If umask_override is
                       not set, sudo will set the umask to be the union of
                       the user's umask and what is specified in sudoers.
                       This flag is off 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 sub-string
                       match on the server unless the NETGROUP_BASE direc‐
                       tive is present in the /etc/ldap.conf file.  If net‐
                       groups are not needed, this option can be disabled to
                       reduce the load on the LDAP server.  This flag is on
                       by default.

     use_pty           If set, and sudo is running in a terminal, the com‐
                       mand will be run in a pseudo-terminal (even if no I/O
                       logging is being done).  If the sudo process is not
                       attached to a terminal, use_pty has no effect.

                       A malicious program run under sudo may be capable of
                       injecting commands into the user's terminal or run‐
                       ning a background process that retains access to the
                       user's terminal device even after the main program
                       has finished executing.  By running the command in a
                       separate pseudo-terminal, this attack is no longer
                       possible.  This flag is off by default.

     user_command_timeouts
                       If set, the user may specify a timeout on the command
                       line.  If the timeout expires before the command has
                       exited, the command will be terminated.  If a timeout
                       is specified both in the sudoers file and on the com‐
                       mand line, the smaller of the two timeouts will be
                       used.  See the Timeout_Spec section for a description
                       of the timeout syntax.  This flag is off by default.

                       This setting is only supported by version 1.8.20 or
                       higher.

     utmp_runas        If set, sudo will store the name of the runas user
                       when updating the utmp (or utmpx) file.  By default,
                       sudo stores the name of the invoking user.  This flag
                       is off by default.

     visiblepw         By default, sudo will refuse to run if the user must
                       enter a password but it is not possible to disable
                       echo on the terminal.  If the visiblepw flag is set,
                       sudo 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 com‐
                       mand.  This flag is off by default.

     Integers:

     closefrom         Before it executes a command, sudo will close all
                       open file descriptors other than standard input,
                       standard output and standard error (ie: file descrip‐
                       tors 0-2).  The closefrom option can be used to spec‐
                       ify a different file descriptor at which to start
                       closing.  The default is 3.

     command_timeout   The maximum amount of time a command is allowed to
                       run before it is terminated.  See the Timeout_Spec
                       section for a description of the timeout syntax.

                       This setting is only supported by version 1.8.20 or
                       higher.

     log_server_timeout
                       The maximum amount of time to wait when connecting to
                       a log server or waiting for a server response.  See
                       the Timeout_Spec section for a description of the
                       timeout syntax.  The default value is 30 seconds.

                       This setting is only supported by version 1.9.0 or
                       higher.

     maxseq            The maximum sequence number that will be substituted
                       for the “%{seq}” escape in the I/O log file (see the
                       iolog_dir description below for more information).
                       While the value substituted for “%{seq}” is in base
                       36, maxseq 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
                       maxseq, it will “roll over” to zero, after which
                       sudoers 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 sudo logs the failure and exits.  The
                       default is 3.

     syslog_maxlen     On many systems, syslog(3) has a relatively small log
                       buffer.  IETF RFC 5424 states that syslog servers
                       must support messages of at least 480 bytes and
                       should support messages up to 2048 bytes.  By
                       default, sudoers creates log messages up to 980 bytes
                       which corresponds to the historic BSD syslog imple‐
                       mentation which used a 1024 byte buffer to store the
                       message, date, hostname and program name.  To prevent
                       syslog messages from being truncated, sudoers will
                       split up log messages that are larger than
                       syslog_maxlen bytes.  When a message is split, addi‐
                       tional parts will include the string “(command
                       continued)” after the user name and before the con‐
                       tinued command line arguments.

                       This setting is only supported by version 1.8.19 or
                       higher.

     Integers that can be used in a boolean context:

     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 sudo 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 sudo will
                       ask for a passwd again.  The timeout may include a
                       fractional component if minute granularity is insuf‐
                       ficient, 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             File mode creation mask to use when running the com‐
                       mand.  Negate this option or set it to 0777 to pre‐
                       vent sudoers from changing the umask.  Unless the
                       umask_override flag is set, the actual umask will be
                       the union of the user's umask and the value of the
                       umask setting, which defaults to 0022.  This guaran‐
                       tees that sudo never lowers the umask when running a
                       command.

                       If umask is explicitly set in sudoers, it will over‐
                       ride any umask setting in PAM or login.conf.  If
                       umask is not set in sudoers, the umask specified by
                       PAM or login.conf will take precedence.  The umask
                       setting in PAM is not used for sudoedit, which does
                       not create a new PAM session.

     Strings:

     authfail_message  Message that is displayed after a user fails to
                       authenticate.  The message may include the ‘%d’
                       escape which will expand to the number of failed
                       password attempts.  If set, it overrides the default
                       message, %d incorrect password attempt(s).

     badpass_message   Message that is displayed if a user enters an incor‐
                       rect password.  The default is Sorry, try again.
                       unless insults are enabled.

     editor            A colon (‘:’) separated list of editors path names
                       used by sudoedit and visudo.  For sudoedit, this list
                       is used to find an editor when none of the
                       SUDO_EDITOR, VISUAL or EDITOR environment variables
                       are set to an editor that exists and is executable.
                       For visudo, it is used as a white list of allowed
                       editors; visudo will choose the editor that matches
                       the user's SUDO_EDITOR, VISUAL or EDITOR environment
                       variable if possible, or the first editor in the list
                       that exists and is executable if not.  Unless invoked
                       as sudoedit, sudo does not preserve the SUDO_EDITOR,
                       VISUAL or EDITOR environment variables unless they
                       are present in the env_keep list or the env_reset
                       option is disabled.  The default is vi.

     iolog_dir         The top-level directory to use when constructing the
                       path name for the input/output log directory.  Only
                       used if the log_input or log_output 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
                       /var/log/sudo-io.

                       The following percent (‘%’) escape sequences are sup‐
                       ported:

                       %{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., 01/00/A5

                       %{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 com‐
                             mand will be run as (e.g., root)

                       %{runas_group}
                             expanded to the group name of the user the com‐
                             mand 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 iolog_dir, in which to
                       store input/output logs when the log_input or
                       log_output options are enabled or when the LOG_INPUT
                       or LOG_OUTPUT tags are present for a command.  Note
                       that iolog_file may contain directory components.
                       The default is “%{seq}”.

                       See the iolog_dir option above for a list of sup‐
                       ported 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 iolog_dir and
                       iolog_file already exists, the existing I/O log file
                       will be truncated and overwritten unless iolog_file
                       ends in six or more Xs.

     iolog_flush       If set, sudo will flush I/O log data to disk after
                       each write instead of buffering it.  This makes it
                       possible to view the logs in real-time as the program
                       is executing but may significantly reduce the effec‐
                       tiveness of I/O log compression.  This flag is off by
                       default.

                       This setting is only supported by version 1.8.20 or
                       higher.

     iolog_group       The group name to look up when setting the group-ID
                       on new I/O log files and directories.  If iolog_group
                       is not set, the primary group-ID of the user speci‐
                       fied by iolog_user is used.  If neither iolog_group
                       nor iolog_user are set, I/O log files and directories
                       are created with group-ID 0.

                       This setting is only supported by version 1.8.19 or
                       higher.

     iolog_mode        The file mode to use when creating I/O log files.
                       Mode bits for read and write permissions for owner,
                       group or other are honored, everything else is
                       ignored.  The file permissions will always include
                       the owner read and write bits, even if they are not
                       present in the specified mode.  When creating I/O log
                       directories, search (execute) bits are added to match
                       the read and write bits specified by iolog_mode.
                       Defaults to 0600 (read and write by user only).

                       This setting is only supported by version 1.8.19 or
                       higher.

     iolog_user        The user name to look up when setting the user and
                       group-IDs on new I/O log files and directories.  If
                       iolog_group is set, it will be used instead of the
                       user's primary group-ID.  By default, I/O log files
                       and directories are created with user and group-ID 0.

                       This setting can be useful when the I/O logs are
                       stored on a Network File System (NFS) share.  Having
                       a dedicated user own the I/O log files means that
                       sudoers does not write to the log files as user-ID 0,
                       which is usually not permitted by NFS.

                       This setting is only supported by version 1.8.19 or
                       higher.

     lecture_status_dir
                       The directory in which sudo stores per-user lecture
                       status files.  Once a user has received the lecture,
                       a zero-length file is created in this directory so
                       that sudo will not lecture the user again.  This
                       directory should not be cleared when the system
                       reboots.  The default is /var/db/sudo/lectured.

     log_server_cabundle
                       The path to a certificate authority bundle file, in
                       PEM format, to use instead of the system's default
                       certificate authority database when authenticating
                       the log server.  The default is to use the system's
                       default certificate authority database.  This setting
                       has no effect unless the log_server flag is enabled
                       and the remote log server is secured with TLS.

     log_server_peer_cert
                       The path to the client's certificate file, in PEM
                       format.  This setting is required when the log_server
                       flag is enabled and the remote log server is secured
                       with TLS.

     log_server_peer_key
                       The path to the client's private key file, in PEM
                       format.  This setting is required when the log_server
                       flag is enabled and the remote log server is secured
                       with TLS.

     mailsub           Subject of the mail sent to the mailto user.  The
                       escape %h will expand to the host name of the
                       machine.  Default is “*** SECURITY information for %h
                       ***”.

     noexec_file       As of sudo version 1.8.1 this option is no longer
                       supported.  The path to the noexec file should now be
                       set in the sudo.conf(5) file.

     pam_login_service
                       On systems that use PAM for authentication, this is
                       the service name used when the -i option is speci‐
                       fied.  The default value is “sudo”.  See the descrip‐
                       tion of pam_service 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 ser‐
                       vice name specifies the PAM policy to apply.  This
                       usually corresponds to an entry in the pam.conf file
                       or a file in the /etc/pam.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 -p option or the
                       SUDO_PROMPT environment variable.  The following per‐
                       cent (‘%’) 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 fqdn 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 rootpw, targetpw and
                             runaspw flags in sudoers)

                       %U    expanded to the login name of the user the com‐
                             mand 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

                       On systems that use PAM for authentication,
                       passprompt will only be used if the prompt provided
                       by the PAM module matches the string “Password: ” or
                       “username's Password: ”.  This ensures that the
                       passprompt setting does not interfere with challenge-
                       response style authentication.  The
                       passprompt_override flag can be used to change this
                       behavior.

                       The default value is “Password: ”.

     runas_default     The default user to run commands as if the -u option
                       is not specified on the command line.  This defaults
                       to root.

     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”.

     timestamp_type    sudoers uses per-user time stamp files for credential
                       caching.  The timestamp_type option can be used to
                       specify the type of time stamp record used.  It has
                       the following possible values:

                       global  A single time stamp record is used for all of
                               a user's login sessions, regardless of the
                               terminal or parent process ID.  An additional
                               record is used to serialize password prompts
                               when sudo is used multiple times in a pipe‐
                               line, but this does not affect authentica‐
                               tion.

                       ppid    A single time stamp record is used for all
                               processes with the same parent process ID
                               (usually the shell).  Commands run from the
                               same shell (or other common parent process)
                               will not require a password for
                               timestamp_timeout minutes (5 by default).
                               Commands run via sudo with a different parent
                               process ID, for example from a shell script,
                               will be authenticated separately.

                       tty     One time stamp record is used for each termi‐
                               nal, which means that a user's login sessions
                               are authenticated separately.  If no terminal
                               is present, the behavior is the same as ppid.
                               Commands run from the same terminal will not
                               require a password for timestamp_timeout min‐
                               utes (5 by default).

                       kernel  The time stamp is stored in the kernel as an
                               attribute of the terminal device.  If no ter‐
                               minal is present, the behavior is the same as
                               ppid.  Negative timestamp_timeout values are
                               not supported and positive values are limited
                               to a maximum of 60 minutes.  This is cur‐
                               rently only supported on OpenBSD.

                       The default value is tty.

                       This setting is only supported by version 1.8.21 or
                       higher.

     timestampdir      The directory in which sudo stores its time stamp
                       files.  This directory should be cleared when the
                       system reboots.  The default is /sudo/ts.

     timestampowner    The owner of the lecture status directory, time stamp
                       directory and all files stored therein.  The default
                       is root.

     Strings that can be used in a boolean context:

     env_file      The env_file 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 enclosed in
                   single or double quotes.  Variables in this file are only
                   added if the variable does not already exist in the envi‐
                   ronment.  This file is considered to be part of the secu‐
                   rity policy, its contents are not subject to other sudo
                   environment restrictions such as env_keep and env_check.

     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.

     fdexec        Determines whether sudo will execute a command by its
                   path or by an open file descriptor.  It has the following
                   possible values:

                   always  Always execute by file descriptor.

                   never   Never execute by file descriptor.

                   digest_only
                           Only execute by file descriptor if the command
                           has an associated digest in the sudoers file.

                   The default value is digest_only.  This avoids a time of
                   check versus time of use race condition when the command
                   is located in a directory writable by the invoking user.

                   Note that fdexec will change the first element of the
                   argument vector for scripts ($0 in the shell) due to the
                   way the kernel runs script interpreters.  Instead of
                   being a normal path, it will refer to a file descriptor.
                   For example, /dev/fd/4 on Solaris and /proc/self/fd/4 on
                   Linux.  A workaround is to use the SUDO_COMMAND environ‐
                   ment variable instead.

                   The fdexec setting is only used when the command is
                   matched by path name.  It has no effect if the command is
                   matched by the built-in ALL alias.

                   This setting is only supported by version 1.8.20 or
                   higher.  If the operating system does not support the
                   fexecve(2) system call, this setting has no effect.

     group_plugin  A string containing a sudoers group plugin with optional
                   arguments.  The string should consist of the plugin path,
                   either fully-qualified or relative to the
                   /usr/local/libexec/sudo directory, followed by any con‐
                   figuration arguments the plugin requires.  These argu‐
                   ments (if any) will be passed to the plugin's initializa‐
                   tion 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
                           sudo.

                   If no value is specified, a value of once is implied.
                   Negating the option results in a value of never being
                   used.  The default value is once.

     lecture_file  Path to a file containing an alternate sudo lecture that
                   will be used in place of the standard lecture if the
                   named file exists.  By default, sudo uses a built-in lec‐
                   ture.

     listpw        This option controls when a password will be required
                   when a user runs sudo with the -l option.  It has the
                   following possible values:

                   all       All the user's sudoers 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 -l option.

                   any       At least one of the user's sudoers 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
                             -l option.

                   If no value is specified, a value of any is implied.
                   Negating the option results in a value of never being
                   used.  The default value is any.

     logfile       Path to the sudo log file (not the syslog log file).
                   Setting a path turns on logging to a file; negating this
                   option turns it off.  By default, sudo logs via syslog.

     mailerflags   Flags to use when invoking mailer.  Defaults to -t.

     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 warn‐
                   ing and error mail.  The address should be enclosed in
                   double quotes ("") to protect against sudo interpreting
                   the @ sign.  Defaults to the name of the user running
                   sudo.

     mailto        Address to send warning and error mail to.  The address
                   should be enclosed in double quotes ("") to protect
                   against sudo interpreting the @ sign.  Defaults to root.

     restricted_env_file
                   The restricted_env_file option specifies the fully quali‐
                   fied 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
                   enclosed in single or double quotes.  Variables in this
                   file are only added if the variable does not already
                   exist in the environment.  Unlike env_file, the file's
                   contents are not trusted and are processed in a manner
                   similar to that of the invoking user's environment.  If
                   env_reset is enabled, variables in the file will only be
                   added if they are matched by either the env_check or
                   env_keep list.  If env_reset is disabled, variables in
                   the file are added as long as they are not matched by the
                   env_delete list.  In either case, the contents of
                   restricted_env_file are processed before the contents of
                   env_file.

     secure_path   If set, sudo will use this value in place of the user's
                   PATH environment variable.  This option can be used to
                   reset the PATH to a known good value that contains direc‐
                   tories for system administrator commands such as
                   /usr/sbin.

                   Users in the group specified by the exempt_group option
                   are not affected by secure_path.  This option is not set
                   by default.

     syslog        Syslog facility if syslog is being used for logging
                   (negate to disable syslog logging).  Defaults to
                   authpriv.

                   The following syslog facilities are supported: authpriv
                   (if your OS supports it), auth, daemon, user, local0,
                   local1, local2, local3, local4, local5, local6, and
                   local7.

     syslog_badpri
                   Syslog priority to use when the user is not allowed to
                   run a command or when authentication is unsuccessful.
                   Defaults to alert.

                   The following syslog priorities are supported: alert,
                   crit, debug, emerg, err, info, notice, warning, and none.
                   Negating the option or setting it to a value of none will
                   disable logging of unsuccessful commands.

     syslog_goodpri
                   Syslog priority to use when the user is allowed to run a
                   command and authentication is successful.  Defaults to
                   notice.

                   See syslog_badpri for the list of supported syslog prior‐
                   ities.  Negating the option or setting it to a value of
                   none will disable logging of successful commands.

     verifypw      This option controls when a password will be required
                   when a user runs sudo with the -v option.  It has the
                   following possible values:

                   all     All the user's sudoers file entries for the cur‐
                           rent host must have the NOPASSWD flag set to
                           avoid entering a password.

                   always  The user must always enter a password to use the
                           -v option.

                   any     At least one of the user's sudoers 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
                           -v option.

                   If no value is specified, a value of all is implied.
                   Negating the option results in a value of never being
                   used.  The default value is all.

     Lists that can be used in a boolean context:

     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 vari‐
                       able's value does not contain any ‘%’ or ‘/’ charac‐
                       ters.  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:

                       ·  It consists of a fully-qualified path name,
                          optionally prefixed with a colon (‘:’), that does
                          not match the location of the zoneinfo directory.

                       ·  It contains a .. path element.

                       ·  It contains white space or non-printable charac‐
                          ters.

                       ·  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 dis‐
                       abled by using the =, +=, -=, and ! operators respec‐
                       tively.  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
                       sudo is run by root with the -V option.

     env_delete        Environment variables to be removed from the user's
                       environment when the env_reset 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 ! oper‐
                       ators respectively.  The global list of environment
                       variables to remove is displayed when sudo is run by
                       root with the -V option.  Note that many operating
                       systems will remove potentially dangerous variables
                       from the environment of any set-user-ID process (such
                       as sudo).

     env_keep          Environment variables to be preserved in the user's
                       environment when the env_reset option is in effect.
                       This allows fine-grained control over the environment
                       sudo-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 sudo is run by root with the -V option.

                       Preserving the HOME environment variable has security
                       implications since many programs use it when search‐
                       ing for configuration or data files.  Adding HOME to
                       env_keep may enable a user to run unrestricted com‐
                       mands via sudo and is strongly discouraged.  Users
                       wishing to edit files with sudo should run sudoedit
                       (or sudo -e) to get their accustomed editor configu‐
                       ration instead of invoking the editor directly.

     log_servers       A list of one or more remote servers to use for I/O
                       log storage, separated by white space.  Starting with
                       sudo 1.9, it is possible to send I/O logs to a remote
                       server instead of logging them locally.  Log servers
                       must be running sudo_logsrvd or another service that
                       implements the protocol described by
                       sudo_logsrv.proto(5).

                       Server addresses should be of the form
                       “host[:port][(tls)]”.  The host portion may be a host
                       name, an IPv4 address, or an IPv6 address in square
                       brackets.

                       If the optional tls flag is present, the connection
                       will be secured with Transport Layer Security (TLS)
                       version 1.2 or 1.3.  Versions of TLS prior to 1.2 are
                       not supported.

                       If a port is specified, it may either be a port num‐
                       ber or a known service name as defined by the system
                       service name database.  If no port is specified, port
                       30343 will be used for plaintext connections and port
                       30344 will be used for TLS connections.

                       When log_servers is enabled, I/O logs will not be
                       logged locally.  If multiple hosts are specified,
                       sudoers will try them in reverse order until it con‐
                       nects successfully.  If no log servers are reachable,
                       the user will not be able to run a command unless the
                       ignore_iolog_errors flag is set.  If the connection
                       to the log server is interrupted while the command is
                       running, the command will be killed unless
                       ignore_iolog_errors is set.

GROUP PROVIDER PLUGINS         top

     The sudoers 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 group_plugin setting.  The
     argument to group_plugin should consist of the plugin path, either
     fully-qualified or relative to the /usr/local/libexec/sudo 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 dou‐
     ble quotes ("").

     The following group provider plugins are installed by default:

     group_file
               The group_file plugin supports an alternate group file that
               uses the same syntax as the /etc/group 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 /etc/sudo-group:

               Defaults group_plugin="group_file.so /etc/sudo-group"

     system_group
               The system_group plugin supports group lookups via the stan‐
               dard C library functions getgrnam() and getgrid().  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(5).

LOG FORMAT         top

     sudoers can log events using either syslog(3) or a simple log file.
     The log format is almost identical in both cases.

   Accepted command log entries
     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 dae‐
                   mon.  If logging to a file and the log_year option is
                   enabled, the date will also include the year.

     hostname      The name of the host sudo was run on.  This field is only
                   present when logging via syslog(3).

     progname      The name of the program, usually sudo or sudoedit.  This
                   field is only present when logging via syslog(3).

     username      The login name of the user who ran sudo.

     ttyname       The short name of the terminal (e.g., “console”, “tty01”,
                   or “pts/0”) sudo was run on, or “unknown” if there was no
                   terminal present.

     cwd           The current working directory that sudo 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 com‐
                   mand's output.  This is only present when the log_input
                   or log_output 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 sudoers_locale, which
     defaults to the “C” locale.

   Denied command log entries
     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 sudoers file.

     user NOT authorized on host
       The user is listed in the sudoers file but is not allowed to run com‐
       mands on the host.

     command not allowed
       The user is listed in the sudoers 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 passwd_tries option.

     a password is required
       The -n 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 sudoers.

   Error log entries
     If an error occurs, sudoers 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
       sudoers 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 sudoers file contains one or more unknown Defaults settings.
       This does not prevent sudo from running, but the sudoers file should
       be checked using visudo.

     timestamp owner (username): No such user
       The time stamp directory owner, as specified by the timestampowner
       setting, could not be found in the password database.

     unable to open/read /etc/sudoers
       The sudoers file could not be opened for reading.  This can happen
       when the sudoers file is located on a remote file system that maps
       user-ID 0 to a different value.  Normally, sudoers tries to open the
       sudoers file using group permissions to avoid this problem.  Consider
       either changing the ownership of /etc/sudoers or adding an argument
       like “sudoers_uid=N” (where ‘N’ is the user-ID that owns the sudoers
       file) to the end of the sudoers Plugin line in the sudo.conf(5) file.

     unable to stat /etc/sudoers
       The /etc/sudoers file is missing.

     /etc/sudoers is not a regular file
       The /etc/sudoers file exists but is not a regular file or symbolic
       link.

     /etc/sudoers is owned by uid N, should be 0
       The sudoers file has the wrong owner.  If you wish to change the
       sudoers file owner, please add “sudoers_uid=N” (where ‘N’ is the
       user-ID that owns the sudoers file) to the sudoers Plugin line in the
       sudo.conf(5) file.

     /etc/sudoers is world writable
       The permissions on the sudoers file allow all users to write to it.
       The sudoers 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 sudoers
       Plugin line in the sudo.conf(5) file.

     /etc/sudoers is owned by gid N, should be 1
       The sudoers file has the wrong group ownership.  If you wish to
       change the sudoers file group ownership, please add “sudoers_gid=N”
       (where ‘N’ is the group-ID that owns the sudoers file) to the sudoers
       Plugin line in the sudo.conf(5) file.

     unable to open /sudo/ts/username
       sudoers was unable to read or create the user's time stamp file.
       This can happen when timestampowner is set to a user other than root
       and the mode on /sudo is not searchable by group or other.  The
       default mode for /sudo is 0711.

     unable to write to /sudo/ts/username
       sudoers was unable to write to the user's time stamp file.

     /sudo/ts is owned by uid X, should be Y
       The time stamp directory is owned by a user other than
       timestampowner.  This can occur when the value of timestampowner has
       been changed.  sudoers will ignore the time stamp directory until the
       owner is corrected.

     /sudo/ts is group writable
       The time stamp directory is group-writable; it should be writable
       only by timestampowner.  The default mode for the time stamp direc‐
       tory is 0700.  sudoers will ignore the time stamp directory until the
       mode is corrected.

   Notes on logging via syslog
     By default, sudoers logs messages via syslog(3).  The date, hostname,
     and progname fields are added by the system's syslog() function, not
     sudoers itself.  As such, they may vary in format on different systems.

     The maximum size of syslog messages varies from system to system.  The
     syslog_maxlen setting can be used to change the maximum syslog message
     size from the default value of 980 bytes.  For more information, see
     the description of syslog_maxlen.

   Notes on logging to a file
     If the logfile option is set, sudoers will log to a local file, such as
     /var/log/sudo.  When logging to a file, sudoers uses a format similar
     to syslog(3), with a few important differences:

     1.   The progname and hostname fields are not present.

     2.   If the log_year option is enabled, the date will also include the
          year.

     3.   Lines that are longer than loglinelen characters (80 by default)
          are word-wrapped and continued on the next line with a four char‐
          acter 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 loglinelen option is set to 0 (or negated with a
          ‘!’), word wrap will be disabled.

I/O LOG FILES         top

     When I/O logging is enabled, sudo will run the command in a pseudo-ter‐
     minal and log all user input and/or output, depending on which options
     are enabled.  I/O can be logged either to the local machine or to a
     remote log server.  For local logs, I/O is logged to the directory
     specified by the iolog_dir option (/var/log/sudo-io by default) using a
     unique session ID that is included in the sudo log line, prefixed with
     “TSID=”.  The iolog_file option may be used to control the format of
     the session ID.  For remote logs, the log_servers setting is used to
     specify one or more log servers running sudo_logsrvd or another server
     that implements the protocol described by sudo_logsrv.proto(5).

     For both local and remote I/O logs, each log is stored in a separate
     directory that contains the following files:

     log       A text file containing information about the command.  The
               first line consists of the following colon-delimited fields:
               the time the command was run, the name of the user who ran
               sudo, the name of the target user, the name of the target
               group (optional), the terminal that sudo was run from, and
               the number of lines and columns of the terminal.  The second
               and third lines contain the working directory the command was
               run from and the path name of the command itself (with argu‐
               ments if present).

     timing    Timing information used to replay the session.  Each line
               consists of the I/O log entry type and amount of time since
               the last entry, followed by type-specific data.  The I/O log
               entry types and their corresponding type-specific data are:

               0     standard input, number of bytes in the entry
               1     standard output, number of bytes in the entry
               2     standard error, number of bytes in the entry
               3     terminal input, number of bytes in the entry
               4     terminal output, number of bytes in the entry
               5     window change, new number lines and columns
               6     bug compatibility for sudo 1.8.7 terminal output
               7     command suspend or resume, signal received

     ttyin     Raw input from the user's terminal, exactly as it was
               received.  No post-processing is performed.  For manual view‐
               ing, you may wish to convert carriage return characters in
               the log to line feeds.  For example: ‘gunzip -c ttyin | tr
               "\r" "\n"’

     stdin     The standard input when no terminal is present, or input
               redirected from a pipe or file.

     ttyout    Output from the pseudo-terminal (what the command writes to
               the screen).  Note that terminal-specific post-processing is
               performed before the data is logged.  This means that, for
               example, line feeds are usually converted to line feed/car‐
               riage return pairs and tabs may be expanded to spaces.

     stdout    The standard output when no terminal is present, or output
               redirected to a pipe or file.

     stderr    The standard error redirected to a pipe or file.

     All files other than log are compressed in gzip format unless the
     compress_io flag has been disabled.  Due to buffering, it is not nor‐
     mally possible to display the I/O logs in real-time as the program is
     executing.  The I/O log data will not be complete until the program run
     by sudo has exited or has been terminated by a signal.  The iolog_flush
     flag can be used to disable buffering, in which case I/O log data is
     written to disk as soon as it is available.  The output portion of an
     I/O log file can be viewed with the sudoreplay(8) utility, which can
     also be used to list or search the available logs.

     Note that user input may contain sensitive information such as pass‐
     words (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 log_output or LOG_OUTPUT is all that is required.

     Since each session's I/O logs are stored in a separate directory, tra‐
     ditional 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 maxseq option to the maximum number of logs you wish to store.
     Once the I/O log sequence number reaches maxseq, it will be reset to
     zero and sudoers will truncate and re-use any existing I/O logs.

FILES         top

     /etc/sudo.conf            Sudo front end configuration

     /etc/sudoers              List of who can run what

     /etc/group                Local groups file

     /etc/netgroup             List of network groups

     /var/log/sudo-io          I/O log files

     /sudo/ts                  Directory containing time stamps for the
                               sudoers security policy

     /var/db/sudo/lectured     Directory containing lecture status files for
                               the sudoers security policy

     /etc/environment          Initial environment for -i mode on AIX and
                               Linux systems

EXAMPLES         top

     Below are example sudoers file entries.  Admittedly, some of these are
     a bit contrived.  First, we allow a few environment variables to pass
     and then define our aliases:

     # 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 sudo
     to log via syslog(3) using the auth facility in all cases.  We don't
     want to subject the full time staff to the sudo lecture, user millert
     need not give a password, and we don't want to reset the LOGNAME or
     USER environment variables when running commands as root.  Addition‐
     ally, on the machines in the SERVERS 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 (/usr/bin/more,
     /usr/bin/pg and /usr/bin/less).  Note that this will not effectively
     constrain users with sudo ALL 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 User specification is the part that actually determines who may run
     what.

     root            ALL = (ALL) ALL
     %wheel          ALL = (ALL) ALL

     We let root and any user in group wheel run any command on any host as
     any user.

     FULLTIMERS      ALL = NOPASSWD: ALL

     Full time sysadmins (millert, mikef, and dowdy) may run any command on
     any host without authenticating themselves.

     PARTTIMERS      ALL = ALL

     Part time sysadmins bostley, jwfox, and crawl) 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 jack may run any command on the machines in the CSNETS 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 CSNETS, the local machine's netmask will be used during matching.

     lisa            CUNETS = ALL

     The user lisa may run any command on any host in the CUNETS alias (the
     class B network 128.138.0.0).

     operator        ALL = DUMPS, KILL, SHUTDOWN, HALT, REBOOT, PRINTING,\
                     sudoedit /etc/printcap, /usr/oper/bin/

     The operator 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 /usr/oper/bin/.  Note that one command in the DUMPS
     Cmnd_Alias includes a sha224 digest, /home/operator/bin/start_backups.
     This is because the directory containing the script is writable by the
     operator user.  If the script is modified (resulting in a digest mis‐
     match) it will no longer be possible to run it via sudo.

     joe             ALL = /usr/bin/su operator

     The user joe 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 opers group may run commands in /usr/sbin/ as themselves
     with any group in the ADMINGRP Runas_Alias (the adm and oper groups).

     The user pete is allowed to change anyone's password except for root on
     the HPPA machines.  Because command line arguments are matched as a
     single, concatenated string, the ‘*’ wildcard will match multiple
     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 bob may run anything on the SPARC and SGI machines as any user
     listed in the OP Runas_Alias (root and operator.)

     jim             +biglab = ALL

     The user jim may run any command on machines in the biglab netgroup.
     sudo knows that “biglab” is a netgroup due to the ‘+’ prefix.

     +secretaries    ALL = PRINTING, /usr/bin/adduser, /usr/bin/rmuser

     Users in the secretaries 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 fred can run commands as any user in the DB Runas_Alias
     (oracle or sybase) without giving a password.

     john            ALPHA = /usr/bin/su [!-]*, !/usr/bin/su *root*

     On the ALPHA machines, user john 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 jen may run any command on any machine except for those in the
     SERVERS Host_Alias (master, mail, www and ns).

     jill            SERVERS = /usr/bin/, !SU, !SHELLS

     For any machine in the SERVERS Host_Alias, jill may run any commands in
     the directory /usr/bin/ except for those commands belonging to the SU
     and SHELLS Cmnd_Aliases.  While not specifically mentioned in the rule,
     the commands in the PAGERS Cmnd_Alias all reside in /usr/bin and have
     the noexec option set.

     steve           CSNETS = (operator) /usr/local/op_commands/

     The user steve may run any command in the directory /usr/local/op_com‐
     mands/ but only as user operator.

     matt            valkyrie = KILL

     On his personal workstation, valkyrie, matt 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 WEBMASTERS 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.

SECURITY NOTES         top

   Limitations of the ‘!’ operator
     It is generally not effective to “subtract” commands from ALL using the
     ‘!’ operator.  A user can trivially circumvent this by copying the
     desired command to a different name and then executing that.  For exam‐
     ple:

     bill    ALL = ALL, !SU, !SHELLS

     Doesn't really prevent bill from running the commands listed in SU or
     SHELLS 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 rein‐
     forced by policy).

     In general, if a user has sudo ALL 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.

   Security implications of fast_glob
     If the fast_glob 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 sudoers 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 john can still run /usr/bin/passwd root if fast_glob is enabled by
     changing to /usr/bin and running ./passwd root instead.

   Preventing shell escapes
     Once sudo 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 sudo's access control and logging.  Common programs
     that permit shell escapes include shells (obviously), editors, pagina‐
     tors, 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 sudoedit is a better
               solution to running editors via sudo.  Due to the large num‐
               ber 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 environ‐
               ment variable (usually LD_PRELOAD) to an alternate shared
               library.  On such systems, sudo's noexec functionality can be
               used to prevent a program run by sudo 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 emu‐
               lation are not affected.

               The noexec feature is known to work on SunOS, Solaris, *BSD,
               Linux, IRIX, Tru64 UNIX, macOS, 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 (usu‐
               ally ld.so, ld.so.1, dyld, dld.sl, rld, or loader) to see if
               LD_PRELOAD is supported.

               On Solaris 10 and higher, noexec uses Solaris privileges
               instead of the LD_PRELOAD environment variable.

               To enable noexec for a command, use the NOEXEC tag as docu‐
               mented in the User Specification section above.  Here is that
               example again:

               aaron   shanty = NOEXEC: /usr/bin/more, /usr/bin/vi

               This allows user aaron to run /usr/bin/more and /usr/bin/vi
               with noexec 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
               noexec you can always just try it out and check whether shell
               escapes work when noexec 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 sudoedit (see below).

   Secure editing
     The sudoers plugin includes sudoedit support which allows users to
     securely edit files with the editor of their choice.  As sudoedit is a
     built-in command, it must be specified in the sudoers file without a
     leading path.  However, it may take command line arguments just as a
     normal command does.  Wildcards used in sudoedit command line arguments
     are expected to be path names, so a forward slash (‘/’) will not be
     matched by a wildcard.

     Unlike other sudo commands, the editor is run with the permissions of
     the invoking user and with the environment unmodified.  More informa‐
     tion may be found in the description of the -e option in sudo(8).

     For example, to allow user operator to edit the “message of the day”
     file:

           operator        sudoedit /etc/motd

     The operator user then runs sudoedit as follows:

           $ sudoedit /etc/motd

     The editor will run as the operator user, not root, on a temporary copy
     of /etc/motd.  After the file has been edited, /etc/motd will be
     updated with the contents of the temporary copy.

     Users should never be granted sudoedit 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 sudoedit will refuse to edit a file located in a
     writable directory unless the sudoedit_checkdir option has been dis‐
     abled or the invoking user is root.  Additionally, in version 1.8.15
     and higher, sudoedit will refuse to open a symbolic link unless either
     the sudoedit_follow option is enabled or the sudoedit command is pre‐
     fixed with the FOLLOW tag in the sudoers file.

   Time stamp file checks
     sudoers will check the ownership of its time stamp directory (/sudo/ts
     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
     sudo stored time stamp files in /tmp; 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 should be cleared at reboot time, not
     all systems contain a /run or /var/run directory.  To avoid potential
     problems, sudoers 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 sudoers relies on the system
     clock for time stamp validation, it may be possible on such systems for
     a user to run sudo for longer than timestamp_timeout by setting the
     clock back.  To combat this, sudoers uses a monotonic clock (which
     never moves backwards) for its time stamps if the system supports it.

     sudoers 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
     sudoers will log and complain.

     If the timestamp_type option is set to “tty”, the time stamp record
     includes the device number of the terminal the user authenticated with.
     This provides per-terminal granularity but time stamp records may still
     outlive the user's session.

     Unless the timestamp_type option is set to “global”, the time stamp
     record also includes the session ID of the process that last authenti‐
     cated.  This prevents processes in different terminal sessions from
     using the same time stamp record.  On systems where a process's start
     time can be queried, the start time of the session leader is recorded
     in the time stamp record.  If no terminal is present or the
     timestamp_type option is set to “ppid”, the start time of the parent
     process is used instead.  In most cases this will prevent a time stamp
     record from being re-used without the user entering a password when
     logging out and back in again.

DEBUGGING         top

     Versions 1.8.4 and higher of the sudoers 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(5) file.

     The sudoers plugin uses the same debug flag format as the sudo front-
     end: subsystem@priority.

     The priorities used by sudoers, in order of decreasing severity, are:
     crit, err, warn, notice, diag, info, trace and debug.  Each priority,
     when specified, also includes all priorities higher than it.  For exam‐
     ple, a priority of notice would include debug messages logged at notice
     and higher.

     The following subsystems are used by the sudoers plugin:

     alias     User_Alias, Runas_Alias, Host_Alias and Cmnd_Alias processing

     all       matches every subsystem

     audit     BSM and Linux audit code

     auth      user authentication

     defaults  sudoers file Defaults settings

     env       environment handling

     ldap      LDAP-based sudoers

     logging   logging support

     match     matching of users, groups, hosts and netgroups in the sudoers
               file

     netif     network interface handling

     nss       network service switch handling in sudoers

     parser    sudoers file parsing

     perms     permission setting

     plugin    The equivalent of main for the plugin.

     pty       pseudo-terminal related code

     rbtree    redblack tree internals

     sssd      SSSD-based sudoers

     util      utility functions
     For example:

     Debug sudo /var/log/sudo_debug match@info,nss@info

     For more information, see the sudo.conf(5) manual.

SEE ALSO         top

     ssh(1), su(1), fnmatch(3), glob(3), mktemp(3), strftime(3),
     sudo.conf(5), sudo_plugin(5), sudoers.ldap(5), sudoers_timestamp(5),
     sudo(8), visudo(8)

AUTHORS         top

     Many people have worked on sudo over the years; this version consists
     of code written primarily by:

           Todd C. Miller

     See the CONTRIBUTORS file in the sudo distribution
     (https://www.sudo.ws/contributors.html) for an exhaustive list of peo‐
     ple who have contributed to sudo.

CAVEATS         top

     The sudoers file should always be edited by the visudo command which
     locks the file and does grammatical checking.  It is imperative that
     the sudoers file be free of syntax errors since sudo will not run with
     a syntactically incorrect sudoers 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 fqdn option in sudoers.

BUGS         top

     If you feel you have found a bug in sudo, please submit a bug report at
     https://bugzilla.sudo.ws/

SUPPORT         top

     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.

DISCLAIMER         top

     sudo is provided “AS IS” and any express or implied warranties, includ‐
     ing, but not limited to, the implied warranties of merchantability and
     fitness for a particular purpose are disclaimed.  See the LICENSE file
     distributed with sudo or https://www.sudo.ws/license.html for complete
     details.

COLOPHON         top

     This page is part of the sudo (execute a command as another user)
     project.  Information about the project can be found at
     https://www.sudo.ws/.  If you have a bug report for this manual page,
     see ⟨https://bugzilla.sudo.ws/index.cgi⟩.  This page was obtained from
     the project's upstream Git repository
     ⟨https://github.com/sudo-project/sudo⟩ on 2020-06-13.  (At that time,
     the date of the most recent commit that was found in the repository was
     2020-06-11.)  If you discover any rendering problems in this HTML ver‐
     sion of the page, or you believe there is a better or more up-to-date
     source for the page, or you have corrections or improvements to the
     information in this COLOPHON (which is not part of the original manual
     page), send a mail to man-pages@man7.org

Sudo 1.9.1                      May 19, 2020                      Sudo 1.9.1

Pages that refer to this page: proc(5)procfs(5)