-=cut
-Copyright (c) 1994-1996,1998-2004 Todd C. Miller <Todd.Miller@courtesan.com>
+Copyright (c) 1994-1996, 1998-2005, 2007-2010
+ Todd C. Miller <Todd.Miller@courtesan.com>
Permission to use, copy, modify, and distribute this software for any
purpose with or without fee is hereby granted, provided that the above
Agency (DARPA) and Air Force Research Laboratory, Air Force
Materiel Command, USAF, under agreement number F39502-99-1-0512.
-$Sudo: sudoers.pod,v 1.96 2004/09/06 20:45:27 millert Exp $
=pod
=head1 NAME
may run what).
When multiple entries match for a user, they are applied in order.
-Where there are conflicting values, the last match is used (which
-is not necessarily the most specific match).
+Where there are multiple matches, the last match is used (which is
+not necessarily the most specific match).
The I<sudoers> grammar will be described below in Extended Backus-Naur
Form (EBNF). Don't despair if you don't know what EBNF is; it is
expressions. Do not, however, confuse them with "wildcard"
characters, which have different meanings.
-=over 8
+=over 4
=item C<?>
Cmnd_Alias ::= NAME '=' Cmnd_List
- NAME ::= [A-Z]([a-z][A-Z][0-9]_)*
+ NAME ::= [A-Z]([A-Z][0-9]_)*
Each I<alias> definition is of the form
User_List ::= User |
User ',' User_List
- User ::= '!'* username |
+ User ::= '!'* user name |
+ '!'* '#'uid |
'!'* '%'group |
'!'* '+'netgroup |
+ '!'* '%:'nonunix_group |
'!'* User_Alias
-A C<User_List> is made up of one or more usernames, system groups
-(prefixed with '%'), netgroups (prefixed with '+') and other aliases.
-Each list item may be prefixed with one or more '!' operators.
-An odd number of '!' operators negate the value of the item; an even
-number just cancel each other out.
-
- Runas_List ::= Runas_User |
- Runas_User ',' Runas_List
-
- Runas_User ::= '!'* username |
- '!'* '#'uid |
- '!'* '%'group |
- '!'* +netgroup |
- '!'* Runas_Alias
-
-A C<Runas_List> is similar to a C<User_List> except that it can
-also contain uids (prefixed with '#') and instead of C<User_Alias>es
-it can contain C<Runas_Alias>es. Note that usernames and groups
-are matched as strings. In other words, two users (groups) with
-the same uid (gid) are considered to be distinct. If you wish to
-match all usernames with the same uid (e.g. root and toor), you
-can use a uid instead (#0 in the example given).
+A C<User_List> is made up of one or more user names, uids (prefixed
+with '#'), system groups (prefixed with '%'), netgroups (prefixed
+with '+') and C<User_Alias>es. Each list item may be prefixed with
+zero or more '!' operators. An odd number of '!' operators negate
+the value of the item; an even number just cancel each other out.
+
+A C<user name>, C<group>, C<netgroup> or C<nonunix_group> 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.
+
+The C<nonunix_group> syntax depends on the underlying implementation.
+For instance, the QAS AD backend supports the following formats:
+
+=over 4
+
+=item *
+
+Group in the same domain: "Group Name"
+
+=item *
+
+Group in any domain: "Group Name@FULLY.QUALIFIED.DOMAIN"
+
+=item *
+
+Group SID: "S-1-2-34-5678901234-5678901234-5678901234-567"
+
+=back
+
+Note that quotes around group names are optional. Unquoted strings must
+use a backslash (\) to escape spaces and the '@' symbol.
+
+ Runas_List ::= Runas_Member |
+ Runas_Member ',' Runas_List
+
+ Runas_Member ::= '!'* user name |
+ '!'* '#'uid |
+ '!'* '%'group |
+ '!'* +netgroup |
+ '!'* Runas_Alias
+
+A C<Runas_List> is similar to a C<User_List> except that instead
+of C<User_Alias>es it can contain C<Runas_Alias>es. Note that
+user names and groups are matched as strings. In other words, two
+users (groups) with the same uid (gid) are considered to be distinct.
+If you wish to match all user names with the same uid (e.g.E<nbsp>root
+and toor), you can use a uid instead (#0 in the example given).
Host_List ::= Host |
Host ',' Host_List
- Host ::= '!'* hostname |
+ Host ::= '!'* host name |
'!'* ip_addr |
'!'* network(/netmask)? |
'!'* '+'netgroup |
'!'* Host_Alias
-A C<Host_List> is made up of one or more hostnames, IP addresses,
+A C<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.
-If you do not specify a netmask with a network number, the netmask
-of the host's ethernet interface(s) will be used when matching.
-The netmask may be specified either in dotted quad notation (e.g.
-255.255.255.0) or CIDR notation (number of bits, e.g. 24). A hostname
-may include shell-style wildcards (see the L<Wildcards> section below),
-but unless the C<hostname> command on your machine returns the fully
-qualified hostname, you'll need to use the I<fqdn> option for wildcards
-to be useful.
+If you do not specify a netmask along with the network number,
+B<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, the corresponding netmask will be used. The netmask
+may be specified either in standard IP address notation
+(e.g.E<nbsp>255.255.255.0 or ffff:ffff:ffff:ffff::),
+or CIDR notation (number of bits, e.g.E<nbsp>24 or 64). A host name may
+include shell-style wildcards (see the L<Wildcards> section below),
+but unless the C<host name> command on your machine returns the fully
+qualified host name, you'll need to use the I<fqdn> option for
+wildcards to be useful. Note B<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.
Cmnd_List ::= Cmnd |
Cmnd ',' Cmnd_List
- commandname ::= filename |
- filename args |
- filename '""'
+ commandname ::= file name |
+ file name args |
+ file name '""'
Cmnd ::= '!'* commandname |
'!'* directory |
'!'* Cmnd_Alias
A C<Cmnd_List> is a list of one or more commandnames, directories, and other
-aliases. A commandname is a fully qualified filename which may include
+aliases. A commandname is a fully qualified file name which may include
shell-style wildcards (see the L<Wildcards> section below). A simple
-filename allows the user to run the command with any arguments he/she
+file name allows the user to run the command with any arguments he/she
wishes. However, you may also specify command line arguments (including
wildcards). Alternately, you can specify C<""> to indicate that the command
may only be run B<without> command line arguments. A directory is a
-fully qualified pathname ending in a '/'. When you specify a directory
+fully qualified path name ending in a '/'. When you specify a directory
in a C<Cmnd_List>, the user will be able to run any file within that directory
(but not in any subdirectories therein).
(or match the wildcards if there are any). Note that the following
characters must be escaped with a '\' if they are used in command
arguments: ',', ':', '=', '\'. The special command C<"sudoedit">
-is used to permit a user to run B<sudo> with the B<-e> flag (or
+is used to permit a user to run B<sudo> with the B<-e> option (or
as B<sudoedit>). It may take command line arguments just as
a normal command does.
Certain configuration options may be changed from their default
values at runtime via one or more C<Default_Entry> lines. These
may affect all users on any host, all users on a specific host, a
-specific user, or commands being run as a specific user.
+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 C<Cmnd_Alias> and reference
+that instead.
Default_Type ::= 'Defaults' |
- 'Defaults' '@' Host |
- 'Defaults' ':' User |
- 'Defaults' '>' RunasUser
+ 'Defaults' '@' Host_List |
+ 'Defaults' ':' User_List |
+ 'Defaults' '!' Cmnd_List |
+ 'Defaults' '>' Runas_List
Default_Entry ::= Default_Type Parameter_List
It is not an error to use the C<-=> operator to remove an element
that does not exist in a list.
-B<Flags>:
+Defaults entries are parsed in the following order: generic, host
+and user Defaults first, then runas Defaults and finally command
+defaults.
-=over 12
+See L<"SUDOERS OPTIONS"> for a list of supported Defaults parameters.
-=item long_otp_prompt
+=head2 User Specification
-When validating with a One Time Password scheme (B<S/Key> or B<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 I<@long_otp_prompt@>
-by default.
+ User_Spec ::= User_List Host_List '=' Cmnd_Spec_List \
+ (':' Host_List '=' Cmnd_Spec_List)*
-=item ignore_dot
+ Cmnd_Spec_List ::= Cmnd_Spec |
+ Cmnd_Spec ',' Cmnd_Spec_List
-If set, B<sudo> will ignore '.' or '' (current dir) in the C<PATH>
-environment variable; the C<PATH> itself is not modified. This
-flag is I<@ignore_dot@> by default. Currently, while it is possible
-to set I<ignore_dot> in I<sudoers>, its value is not used. This option
-should be considered read-only (it will be fixed in a future version
-of B<sudo>).
+ Cmnd_Spec ::= Runas_Spec? SELinux_Spec? Tag_Spec* Cmnd
-=item mail_always
+ Runas_Spec ::= '(' Runas_List? (':' Runas_List)? ')'
-Send mail to the I<mailto> user every time a users runs B<sudo>.
-This flag is I<off> by default.
+ SELinux_Spec ::= ('ROLE=role' | 'TYPE=type')
-=item mail_badpass
+ Tag_Spec ::= ('NOPASSWD:' | 'PASSWD:' | 'NOEXEC:' | 'EXEC:' |
+ 'SETENV:' | 'NOSETENV:' | 'LOG_INPUT:' | 'NOLOG_INPUT:' |
+ 'LOG_OUTPUT:' | 'NOLOG_OUTPUT:')
-Send mail to the I<mailto> user if the user running sudo does not
-enter the correct password. This flag is I<off> by default.
+A B<user specification> determines which commands a user may run
+(and as what user) on specified hosts. By default, commands are
+run as B<root>, but this can be changed on a per-command basis.
-=item mail_no_user
+The basic structure of a user specification is `who = where (as_whom)
+what'. Let's break that down into its constituent parts:
-If set, mail will be sent to the I<mailto> user if the invoking
-user is not in the I<sudoers> file. This flag is I<@mail_no_user@>
-by default.
+=head2 Runas_Spec
-=item mail_no_host
+A C<Runas_Spec> determines the user and/or the group that a command
+may be run as. A fully-specified C<Runas_Spec> consists of two
+C<Runas_List>s (as defined above) separated by a colon (':') and
+enclosed in a set of parentheses. The first C<Runas_List> indicates
+which users the command may be run as via B<sudo>'s B<-u> option.
+The second defines a list of groups that can be specified via
+B<sudo>'s B<-g> option. If both C<Runas_List>s are specified, the
+command may be run with any combination of users and groups listed
+in their respective C<Runas_List>s. If only the first is specified,
+the command may be run as any user in the list but no B<-g> option
+may be specified. If the first C<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 C<Runas_List>. If no
+C<Runas_Spec> is specified the command may be run as B<root> and
+no group may be specified.
+
+A C<Runas_Spec> sets the default for the commands that follow it.
+What this means is that for the entry:
-If set, mail will be sent to the I<mailto> user if the invoking
-user exists in the I<sudoers> file, but is not allowed to run
-commands on the current host. This flag is I<@mail_no_host@> by default.
+ dgb boulder = (operator) /bin/ls, /bin/kill, /usr/bin/lprm
-=item mail_no_perms
+The user B<dgb> may run F</bin/ls>, F</bin/kill>, and
+F</usr/bin/lprm> -- but only as B<operator>. E.g.,
-If set, mail will be sent to the I<mailto> user if the invoking
-user is allowed to use B<sudo> but the command they are trying is not
-listed in their I<sudoers> file entry or is explicitly denied.
-This flag is I<@mail_no_perms@> by default.
+ $ sudo -u operator /bin/ls.
-=item tty_tickets
+It is also possible to override a C<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
-If set, users must authenticate on a per-tty basis. Normally,
-B<sudo> uses a directory in the ticket dir with the same name as
-the user running it. With this flag enabled, B<sudo> will use a
-file named for the tty the user is logged in on in that directory.
-This flag is I<@tty_tickets@> by default.
+Then user B<dgb> is now allowed to run F</bin/ls> as B<operator>,
+but F</bin/kill> and F</usr/bin/lprm> as B<root>.
+
+We can extend this to allow B<dgb> to run C</bin/ls> with either
+the user or group set to B<operator>:
+
+ dgb boulder = (operator : operator) /bin/ls, (root) /bin/kill, \
+ /usr/bin/lprm
+
+In the following example, user B<tcm> may run commands that access
+a modem device file with the dialer group. Note that in this example
+only the group will be set, the command still runs as user B<tcm>.
+
+ tcm boulder = (:dialer) /usr/bin/tip, /usr/bin/cu, \
+ /usr/local/bin/minicom
+
+=head2 SELinux_Spec
+
+On systems with SELinux support, I<sudoers> entries may optionally have
+an SELinux role and/or type associated with a command. If a role or
+type is specified with the command it will override any default values
+specified in I<sudoers>. A role or type specified on the command line,
+however, will supercede the values in I<sudoers>.
+
+=head2 Tag_Spec
+
+A command may have zero or more tags associated with it. There are
+eight possible tag values, C<NOPASSWD>, C<PASSWD>, C<NOEXEC>,
+C<EXEC>, C<SETENV>, C<NOSETENV>, C<LOG_INPUT>, C<NOLOG_INPUT>,
+C<LOG_OUTPUT> and C<NOLOG_OUTPUT>. Once a tag is set on a C<Cmnd>,
+subsequent C<Cmnd>s in the C<Cmnd_Spec_List>, inherit the tag unless
+it is overridden by the opposite tag (i.e.: C<PASSWD> overrides
+C<NOPASSWD> and C<NOEXEC> overrides C<EXEC>).
+
+=head3 NOPASSWD and PASSWD
+
+By default, B<sudo> requires that a user authenticate him or herself
+before running a command. This behavior can be modified via the
+C<NOPASSWD> tag. Like a C<Runas_Spec>, the C<NOPASSWD> tag sets
+a default for the commands that follow it in the C<Cmnd_Spec_List>.
+Conversely, the C<PASSWD> tag can be used to reverse things.
+For example:
+
+ ray rushmore = NOPASSWD: /bin/kill, /bin/ls, /usr/bin/lprm
+
+would allow the user B<ray> to run F</bin/kill>, F</bin/ls>, and
+F</usr/bin/lprm> as B<root> on the machine rushmore without
+authenticating himself. If we only want B<ray> to be able to
+run F</bin/kill> without a password the entry would be:
+
+ ray rushmore = NOPASSWD: /bin/kill, PASSWD: /bin/ls, /usr/bin/lprm
+
+Note, however, that the C<PASSWD> tag has no effect on users who are
+in the group specified by the I<exempt_group> option.
+
+By default, if the C<NOPASSWD> tag is applied to any of the entries
+for a user on the current host, he or she will be able to run
+C<sudo -l> without a password. Additionally, a user may only run
+C<sudo -v> without a password if the C<NOPASSWD> tag is present
+for all a user's entries that pertain to the current host.
+This behavior may be overridden via the verifypw and listpw options.
+
+=head3 NOEXEC and EXEC
+
+If B<sudo> has been compiled with I<noexec> support and the underlying
+operating system supports it, the C<NOEXEC> tag can be used to prevent
+a dynamically-linked executable from running further commands itself.
+
+In the following example, user B<aaron> may run F</usr/bin/more>
+and F</usr/bin/vi> but shell escapes will be disabled.
+
+ aaron shanty = NOEXEC: /usr/bin/more, /usr/bin/vi
+
+See the L<PREVENTING SHELL ESCAPES> section below for more details
+on how C<NOEXEC> works and whether or not it will work on your system.
+
+=head3 SETENV and NOSETENV
+
+These tags override the value of the I<setenv> option on a per-command
+basis. Note that if C<SETENV> has been set for a command, any
+environment variables set on the command line way are not subject
+to the restrictions imposed by I<env_check>, I<env_delete>, or
+I<env_keep>. As such, only trusted users should be allowed to set
+variables in this manner. If the command matched is B<ALL>, the
+C<SETENV> tag is implied for that command; this default may
+be overridden by use of the C<NOSETENV> tag.
+
+=head3 LOG_INPUT and NOLOG_INPUT
+
+These tags override the value of the I<log_input> option on a
+per-command basis. For more information, see the description of
+I<log_input> in the L<"SUDOERS OPTIONS"> section below.
+
+=head3 LOG_OUTPUT and NOLOG_OUTPUT
+
+These tags override the value of the I<log_output> option on a
+per-command basis. For more information, see the description of
+I<log_output> in the L<"SUDOERS OPTIONS"> section below.
+
+=head2 Wildcards
+
+B<sudo> allows shell-style I<wildcards> (aka meta or glob characters)
+to be used in host names, path names and command line arguments in
+the I<sudoers> file. Wildcard matching is done via the B<POSIX>
+L<glob(3)> and L<fnmatch(3)> routines. Note that these are I<not>
+regular expressions.
+
+=over 8
+
+=item C<*>
+
+Matches any set of zero or more characters.
+
+=item C<?>
+
+Matches any single character.
+
+=item C<[...]>
+
+Matches any character in the specified range.
+
+=item C<[!...]>
+
+Matches any character B<not> in the specified range.
+
+=item C<\x>
+
+For any character "x", evaluates to "x". This is used to
+escape special characters such as: "*", "?", "[", and "}".
+
+=back
+
+POSIX character classes may also be used if your system's L<glob(3)>
+and L<fnmatch(3)> functions support them. However, because the
+C<':'> character has special meaning in I<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 B<not> be matched by
+wildcards used in the path name. When matching the command
+line arguments, however, a slash B<does> get matched by
+wildcards. This is to make a path like:
+
+ /usr/bin/*
+
+match F</usr/bin/who> but not F</usr/bin/X11/xterm>.
+
+=head2 Exceptions to wildcard rules
+
+The following exceptions apply to the above rules:
+
+=over 8
+
+=item C<"">
+
+If the empty string C<""> is the only command line argument in the
+I<sudoers> entry it means that command is not allowed to be run
+with B<any> arguments.
+
+=back
+
+=head2 Including other files from within sudoers
+
+It is possible to include other I<sudoers> files from within the
+I<sudoers> file currently being parsed using the C<#include> and
+C<#includedir> directives.
+
+This can be used, for example, to keep a site-wide I<sudoers> file
+in addition to a local, per-machine file. For the sake of this
+example the site-wide I<sudoers> will be F</etc/sudoers> and the
+per-machine one will be F</etc/sudoers.local>. To include
+F</etc/sudoers.local> from within F</etc/sudoers> we would use the
+following line in F</etc/sudoers>:
+
+=over 4
+
+C<#include /etc/sudoers.local>
+
+=back
+
+When B<sudo> reaches this line it will suspend processing of the
+current file (F</etc/sudoers>) and switch to F</etc/sudoers.local>.
+Upon reaching the end of F</etc/sudoers.local>, the rest of
+F</etc/sudoers> will be processed. Files that are included may
+themselves include other files. A hard limit of 128 nested include
+files is enforced to prevent include file loops.
+
+The file name may include the C<%h> escape, signifying the short form
+of the host name. I.e., if the machine's host name is "xerxes", then
+
+C<#include /etc/sudoers.%h>
+
+will cause B<sudo> to include the file F</etc/sudoers.xerxes>.
+
+The C<#includedir> directive can be used to create a F<sudo.d>
+directory that the system package manager can drop I<sudoers> rules
+into as part of package installation. For example, given:
+
+C<#includedir /etc/sudoers.d>
+
+B<sudo> will read each file in F</etc/sudoers.d>, skipping file
+names that end in C<~> or contain a C<.> character to avoid causing
+problems with package manager or editor temporary/backup files.
+Files are parsed in sorted lexical order. That is,
+F</etc/sudoers.d/01_first> will be parsed before
+F</etc/sudoers.d/10_second>. Be aware that because the sorting is
+lexical, not numeric, F</etc/sudoers.d/1_whoops> would be loaded
+B<after> F</etc/sudoers.d/10_second>. Using a consistent number
+of leading zeroes in the file names can be used to avoid such
+problems.
+
+Note that unlike files included via C<#include>, B<visudo> will not
+edit the files in a C<#includedir> directory unless one of them
+contains a syntax error. It is still possible to run B<visudo>
+with the C<-f> flag to edit the files directly.
+
+=head2 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 uid). Both the comment character and any text
+after it, up to the end of the line, are ignored.
+
+The reserved word B<ALL> is a built-in I<alias> that always causes
+a match to succeed. It can be used wherever one might otherwise
+use a C<Cmnd_Alias>, C<User_Alias>, C<Runas_Alias>, or C<Host_Alias>.
+You should not try to define your own I<alias> called B<ALL> as the
+built-in alias will be used in preference to your own. Please note
+that using B<ALL> can be dangerous since in a command context, it
+allows the user to run B<any> command on the system.
+
+An exclamation point ('!') can be used as a logical I<not> operator
+both in an I<alias> and in front of a C<Cmnd>. This allows one to
+exclude certain values. Note, however, that using a C<!> in
+conjunction with the built-in C<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
+character on the line.
+
+Whitespace between elements in a list as well as special syntactic
+characters in a I<User Specification> ('=', ':', '(', ')') is optional.
+
+The following characters must be escaped with a backslash ('\') when
+used as part of a word (e.g.E<nbsp>a user name or host name):
+'@', '!', '=', ':', ',', '(', ')', '\'.
+
+=head1 SUDOERS OPTIONS
+
+B<sudo>'s behavior can be modified by C<Default_Entry> lines, as
+explained earlier. A list of all supported Defaults parameters,
+grouped by type, are listed below.
+
+B<Boolean Flags>:
+
+=over 16
+
+=item always_set_home
+
+If enabled, B<sudo> will set the C<HOME> environment variable to the
+home directory of the target user (which is root unless the B<-u>
+option is used). This effectively means that the B<-H> option is
+always implied. Note that C<HOME> is already set when the the
+I<env_reset> option is enabled, so I<always_set_home> is only
+effective for configurations where I<env_reset> is disabled.
+This flag is I<off> by default.
=item authenticate
may be overridden via the C<PASSWD> and C<NOPASSWD> tags.
This flag is I<on> by default.
-=item root_sudo
+=item closefrom_override
-If set, root is allowed to run B<sudo> too. Disabling this prevents users
-from "chaining" B<sudo> commands to get a root shell by doing something
-like C<"sudo sudo /bin/sh">. Note, however, that turning off I<root_sudo>
-will also prevent root and from running B<sudoedit>.
-Disabling I<root_sudo> provides no real additional security; it
-exists purely for historical reasons.
-This flag is I<@root_sudo@> by default.
+If set, the user may use B<sudo>'s B<-C> option which
+overrides the default starting point at which B<sudo> begins
+closing open file descriptors. This flag is I<off> by default.
+
+=item compress_io
+
+If set, and B<sudo> is configured to log a command's input or output,
+the I/O logs will be compressed using B<zlib>. This flag is I<on>
+by default when B<sudo> is compiled with B<zlib> support.
+
+=item env_editor
+
+If set, B<visudo> will use the value of the EDITOR or VISUAL
+environment variables before falling back on the default editor list.
+Note that this may create a security hole as it allows the user to
+run any arbitrary command as root without logging. A safer alternative
+is to place a colon-separated list of editors in the C<editor>
+variable. B<visudo> will then only use the EDITOR or VISUAL if
+they match a value specified in C<editor>. This flag is I<@env_editor@> by
+default.
+
+=item env_reset
+
+If set, B<sudo> will reset the environment to only contain the
+LOGNAME, MAIL, SHELL, USER, USERNAME and the C<SUDO_*> variables. Any
+variables in the caller's environment that match the C<env_keep>
+and C<env_check> lists are then added. The default contents of the
+C<env_keep> and C<env_check> lists are displayed when B<sudo> is
+run by root with the I<-V> option. If the I<secure_path> option
+is set, its value will be used for the C<PATH> environment variable.
+This flag is I<on> by default.
+
+=item fast_glob
+
+Normally, B<sudo> uses the L<glob(3)> function to do shell-style
+globbing when matching path names. However, since it accesses the
+file system, L<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 (automounted). The I<fast_glob>
+option causes B<sudo> to use the L<fnmatch(3)> function, which does
+not access the file system to do its matching. The disadvantage
+of I<fast_glob> is that it is unable to match relative path names
+such as F<./ls> or F<../bin/ls>. This has security implications
+when path names that include globbing characters are used with the
+negation operator, C<'!'>, as such rules can be trivially bypassed.
+As such, this option should not be used when I<sudoers> contains rules
+that contain negated path names which include globbing characters.
+This flag is I<off> by default.
+
+=item fqdn
+
+Set this flag if you want to put fully qualified host names in the
+I<sudoers> file. I.e., instead of myhost you would use myhost.mydomain.edu.
+You may still use the short form if you wish (and even mix the two).
+Beware that turning on I<fqdn> requires B<sudo> to make DNS lookups
+which may make B<sudo> unusable if DNS stops working (for example
+if the machine is not plugged into the network). Also note that
+you must use the host's official name as DNS knows it. That is,
+you may not use a host alias (C<CNAME> entry) due to performance
+issues and the fact that there is no way to get all aliases from
+DNS. If your machine's host name (as returned by the C<hostname>
+command) is already fully qualified you shouldn't need to set
+I<fqdn>. This flag is I<@fqdn@> by default.
+
+=item ignore_dot
+
+If set, B<sudo> will ignore '.' or '' (current dir) in the C<PATH>
+environment variable; the C<PATH> itself is not modified. This
+flag is I<@ignore_dot@> by default.
+
+=item ignore_local_sudoers
+
+If set via LDAP, parsing of F<@sysconfdir@/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 F<@sysconfdir@/sudoers>.
+When this option is present, F<@sysconfdir@/sudoers> does not even need to
+exist. Since this option tells B<sudo> how to behave when no specific LDAP
+entries have been matched, this sudoOption is only meaningful for the
+C<cn=defaults> section. This flag is I<off> by default.
+
+=item insults
+
+If set, B<sudo> will insult users when they enter an incorrect
+password. This flag is I<@insults@> by default.
=item log_host
-If set, the hostname will be logged in the (non-syslog) B<sudo> log file.
+If set, the host name will be logged in the (non-syslog) B<sudo> log file.
This flag is I<off> by default.
=item log_year
If set, the four-digit year will be logged in the (non-syslog) B<sudo> log file.
This flag is I<off> by default.
-=item shell_noargs
+=item long_otp_prompt
-If set and B<sudo> is invoked with no arguments it acts as if the
-B<-s> flag had been given. That is, it runs a shell as root (the
-shell is determined by the C<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 I<off> by default.
+When validating with a One Time Password (OPT) scheme such as
+B<S/Key> or B<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 I<@long_otp_prompt@> by default.
-=item set_home
+=item mail_always
-If set and B<sudo> is invoked with the B<-s> flag the C<HOME>
-environment variable will be set to the home directory of the target
-user (which is root unless the B<-u> option is used). This effectively
-makes the B<-s> flag imply B<-H>. This flag is I<off> by default.
+Send mail to the I<mailto> user every time a users runs B<sudo>.
+This flag is I<off> by default.
-=item always_set_home
+=item mail_badpass
-If set, B<sudo> will set the C<HOME> environment variable to the home
-directory of the target user (which is root unless the B<-u> option is used).
-This effectively means that the B<-H> flag is always implied.
-This flag is I<off> by default.
+Send mail to the I<mailto> user if the user running B<sudo> does not
+enter the correct password. This flag is I<off> by default.
+
+=item mail_no_host
+
+If set, mail will be sent to the I<mailto> user if the invoking
+user exists in the I<sudoers> file, but is not allowed to run
+commands on the current host. This flag is I<@mail_no_host@> by default.
+
+=item mail_no_perms
+
+If set, mail will be sent to the I<mailto> user if the invoking
+user is allowed to use B<sudo> but the command they are trying is not
+listed in their I<sudoers> file entry or is explicitly denied.
+This flag is I<@mail_no_perms@> by default.
+
+=item mail_no_user
+
+If set, mail will be sent to the I<mailto> user if the invoking
+user is not in the I<sudoers> file. This flag is I<@mail_no_user@>
+by default.
+
+=item noexec
+
+If set, all commands run via B<sudo> will behave as if the C<NOEXEC>
+tag has been set, unless overridden by a C<EXEC> tag. See the
+description of I<NOEXEC and EXEC> below as well as the L<PREVENTING SHELL
+ESCAPES> section at the end of this manual. This flag is I<off> by default.
=item path_info
location of executables that the normal user does not have access
to. The disadvantage is that if the executable is simply not in
the user's C<PATH>, B<sudo> will tell the user that they are not
-allowed to run it, which can be confusing. This flag is I<off> by
-default.
+allowed to run it, which can be confusing. This flag is I<@path_info@>
+by default.
+
+=item passprompt_override
+
+The password prompt specified by I<passprompt> will normally only
+be used if the password prompt provided by systems such as PAM matches
+the string "Password:". If I<passprompt_override> is set, I<passprompt>
+will always be used. This flag is I<off> by default.
=item preserve_groups
-By default B<sudo> will initialize the group vector to the list of
+By default, B<sudo> will initialize the group vector to the list of
groups the target user is in. When I<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 I<off> by default.
-=item fqdn
-
-Set this flag if you want to put fully qualified hostnames in the
-I<sudoers> file. I.e., instead of myhost you would use myhost.mydomain.edu.
-You may still use the short form if you wish (and even mix the two).
-Beware that turning on I<fqdn> requires B<sudo> to make DNS lookups
-which may make affect B<sudo> performance if DNS stops working (for example
-if the machine is not plugged into the network). The default behavior for
-Debian has been modified to minimize the potential of a problem, but there
-may still be some cases in which lack of working DNS might make sudo work
-very slowly. Also note that
-you must use the host's official name as DNS knows it. That is,
-you may not use a host alias (C<CNAME> entry) due to performance
-issues and the fact that there is no way to get all aliases from
-DNS. If your machine's hostname (as returned by the C<hostname>
-command) is already fully qualified you shouldn't need to set
-I<fqdn>. This flag is I<@fqdn@> by default.
-
-=item insults
+=item pwfeedback
-If set, B<sudo> will insult users when they enter an incorrect
-password. This flag is I<@insults@> by default.
+By default, B<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 B<sudo>
+has hung at this point. When I<pwfeedback> is set, B<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 I<off> by default.
=item requiretty
If set, B<sudo> will only run when the user is logged in to a real
-tty. This will disallow things like C<"rsh somehost sudo ls"> since
-L<rsh(1)> does not allocate a tty. Because it is not possible to turn
-off echo when there is no tty present, some sites may with to set
-this flag to prevent a user from entering a visible password. This
-flag is I<off> by default.
+tty. When this flag is set, B<sudo> can only be run from a login
+session and not via other means such as L<cron(8)> or cgi-bin scripts.
+This flag is I<off> by default.
-=item env_editor
+=item root_sudo
-If set, B<visudo> will use the value of the EDITOR or VISUAL
-environment variables before falling back on the default editor list.
-Note that this may create a security hole as it allows the user to
-run any arbitrary command as root without logging. A safer alternative
-is to place a colon-separated list of editors in the C<editor>
-variable. B<visudo> will then only use the EDITOR or VISUAL if
-they match a value specified in C<editor>. This flag is C<@env_editor@> by
-default.
+If set, root is allowed to run B<sudo> too. Disabling this prevents users
+from "chaining" B<sudo> commands to get a root shell by doing something
+like C<"sudo sudo /bin/sh">. Note, however, that turning off I<root_sudo>
+will also prevent root from running B<sudoedit>.
+Disabling I<root_sudo> provides no real additional security; it
+exists purely for historical reasons.
+This flag is I<@root_sudo@> by default.
=item rootpw
I<runas_default> option (defaults to C<@runas_default@>) instead of the
password of the invoking user. This flag is I<off> by default.
-=item targetpw
+=item set_home
-If set, B<sudo> will prompt for the password of the user specified by
-the B<-u> flag (defaults to C<root>) instead of the password of the
-invoking user. Note that this precludes the use of a uid not listed
-in the passwd database as an argument to the B<-u> flag.
+If enabled and B<sudo> is invoked with the B<-s> option the C<HOME>
+environment variable will be set to the home directory of the target
+user (which is root unless the B<-u> option is used). This effectively
+makes the B<-s> option imply B<-H>. Note that C<HOME> is already
+set when the the I<env_reset> option is enabled, so I<set_home> is
+only effective for configurations where I<env_reset> is disabled.
This flag is I<off> by default.
=item set_logname
-Normally, B<sudo> will set the C<LOGNAME> and C<USER> environment variables
-to the name of the target user (usually root unless the B<-u> flag is given).
-However, since some programs (including the RCS revision control system)
-use C<LOGNAME> to determine the real identity of the user, it may be desirable
-to change this behavior. This can be done by negating the set_logname option.
+Normally, B<sudo> will set the C<LOGNAME>, C<USER> and C<USERNAME>
+environment variables to the name of the target user (usually root
+unless the B<-u> option is given). However, since some programs
+(including the RCS revision control system) use C<LOGNAME> to
+determine the real identity of the user, it may be desirable to
+change this behavior. This can be done by negating the set_logname
+option. Note that if the I<env_reset> option has not been disabled,
+entries in the I<env_keep> list will override the value of
+I<set_logname>. This flag is I<on> by default.
+
+=item setenv
+
+Allow the user to disable the I<env_reset> option from the command
+line. Additionally, environment variables set via the command line
+are not subject to the restrictions imposed by I<env_check>,
+I<env_delete>, or I<env_keep>. As such, only trusted users should
+be allowed to set variables in this manner. This flag is I<off>
+by default.
+
+=item shell_noargs
+
+If set and B<sudo> is invoked with no arguments it acts as if the
+B<-s> option had been given. That is, it runs a shell as root (the
+shell is determined by the C<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 I<off> by default.
=item stay_setuid
changes that behavior such that the real UID is left as the invoking
user's UID. In other words, this makes B<sudo> act as a setuid
wrapper. This can be useful on systems that disable some potentially
-dangerous functionality when a program is run setuid. Note, however,
-that this means that sudo will run with the real uid of the invoking
-user which may allow that user to kill B<sudo> before it can log a
-failure, depending on how your OS defines the interaction between
-signals and setuid processes.
+dangerous functionality when a program is run setuid. This option
+is only effective on systems with either the setreuid() or setresuid()
+function. This flag is I<off> by default.
-=item env_reset
+=item targetpw
-If set, B<sudo> will reset the environment to only contain the
-following variables: C<HOME>, C<LOGNAME>, C<PATH>, C<SHELL>, C<TERM>,
-C<DISPLAY>, C<XAUTHORITY>, C<XAUTHORIZATION>,
-C<LANG>, C<LANGUAGE>, C<LC_*>,
-and C<USER> (in addition to the C<SUDO_*> variables).
-
-Of these, only C<TERM>, C<DISPLAY>, C<XAUTHORITY>, C<XAUTHORIZATION>,
-C<LANG>, C<LANGUAGE>, and C<LC_*> are copied unaltered from the old environment.
-The other variables are set to default values (possibly modified
-by the value of the I<set_logname> option). If B<sudo> was compiled
-with the C<SECURE_PATH> option, its value will be used for the C<PATH>
-environment variable.
+If set, B<sudo> will prompt for the password of the user specified
+by the B<-u> option (defaults to C<root>) instead of the password
+of the invoking user. In addition, the timestamp file name will
+include the target user's name. Note that this flag precludes the
+use of a uid not listed in the passwd database as an argument to
+the B<-u> option. This flag is I<off> by default.
+
+=item log_input
+
+If set, B<sudo> will run the command in a I<pseudo tty> and log all
+user input.
+If the standard input is not connected to the user's tty, due to
+I/O redirection or because the command is part of a pipeline, that
+input is also captured and stored in a separate log file.
-This option is enabled by default.
+Input is logged to the F</var/log/sudo-io> directory using a unique
+session ID that is included in the normal B<sudo> log line, prefixed
+with I<TSID=>.
-Other variables may be preserved with the I<env_keep> option.
+=item log_output
+
+If set, B<sudo> will run the command in a I<pseudo tty> and log all
+output that is sent to the screen, similar to the script(1) command.
+If the standard output or standard error is not connected to the
+user's tty, due to I/O redirection or because the command is part
+of a pipeline, that output is also captured and stored in separate
+log files.
+
+Output is logged to the
+F</var/log/sudo-io> directory using a unique session ID that is
+included in the normal B<sudo> log line, prefixed with I<TSID=>.
+
+Output logs may be viewed with the L<sudoreplay(8)> utility, which
+can also be used to list or search the available logs.
+
+=item tty_tickets
+
+If set, users must authenticate on a per-tty basis. With this flag
+enabled, B<sudo> will use a file named for the tty the user is
+logged in on in the user's time stamp directory. If disabled, the
+time stamp of the directory is used instead. This flag is
+I<@tty_tickets@> by default.
+
+=item umask_override
+
+If set, B<sudo> will set the umask as specified by I<sudoers> without
+modification. This makes it possible to specify a more permissive
+umask in I<sudoers> than the user's own umask and matches historical
+behavior. If I<umask_override> is not set, B<sudo> will set the
+umask to be the union of the user's umask and what is specified in
+I<sudoers>. This flag is I<off> by default.
=item use_loginclass
login class if one exists. Only available if B<sudo> is configured with
the --with-logincap option. This flag is I<off> by default.
-=item noexec
+=item use_pty
-If set, all commands run via sudo will behave as if the C<NOEXEC>
-tag has been set, unless overridden by a C<EXEC> tag. See the
-description of I<NOEXEC and EXEC> below as well as the L<PREVENTING SHELL
-ESCAPES> section at the end of this manual. This flag is I<off> by default.
+If set, B<sudo> will run the command in a pseudo-pty even if no I/O
+logging is being gone. A malicious program run under B<sudo> could
+conceivably fork a background process that retains to the user's
+terminal device after the main program has finished executing. Use
+of this option will make that impossible.
-=item ignore_local_sudoers
+=item visiblepw
-If set via LDAP, parsing of @sysconfdir@/sudoers will be skipped.
-This is intended for an 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 @sysconfdir@/sudoers.
-When this option is present, @sysconfdir@/sudoers does not even need to exist.
-Since this options 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 I<off> by default.
+By default, B<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 I<visiblepw> flag is set, B<sudo> will prompt for a password
+even when it would be visible on the screen. This makes it possible
+to run things like C<"rsh somehost sudo ls"> since L<rsh(1)> does
+not allocate a tty. This flag is I<off> by default.
=back
B<Integers>:
-=over 12
+=over 16
+
+=item closefrom
+
+Before it executes a command, B<sudo> will close all open file
+descriptors other than standard input, standard output and standard
+error (ie: file descriptors 0-2). The I<closefrom> option can be used
+to specify a different file descriptor at which to start closing.
+The default is C<3>.
=item passwd_tries
B<Integers that can be used in a boolean context>:
-=over 12
+=over 16
=item loglinelen
effect on the syslog log file, only the file log. The default is
C<@loglen@> (use 0 or negate the option to disable word wrap).
+=item passwd_timeout
+
+Number of minutes before the B<sudo> password prompt times out, or
+C<0> for no timeout. The timeout may include a fractional component
+if minute granularity is insufficient, for example C<2.5>. The
+default is C<@password_timeout@>.
+
=item timestamp_timeout
Number of minutes that can elapse before B<sudo> will ask for a
-passwd again. The default is C<@timeout@>. Set this to C<0> to always
-prompt for a password.
+passwd again. The timeout may include a fractional component if
+minute granularity is insufficient, for example C<2.5>. The default
+is C<@timeout@>. Set this to C<0> to always prompt for a password.
If set to a value less than C<0> the user's timestamp will never
expire. This can be used to allow users to create or delete their
own timestamps via C<sudo -v> and C<sudo -k> respectively.
-=item passwd_timeout
-
-Number of minutes before the B<sudo> password prompt times out.
-The default is C<@password_timeout@>, set this to C<0> for no password timeout.
-
=item umask
Umask to use when running the command. Negate this option or set
-it to 0777 to preserve the user's umask. The default is C<@sudo_umask@>.
+it to 0777 to preserve the user's umask. The actual umask that is
+used will be the union of the user's umask and the value of the
+I<umask> option, which defaults to C<@sudo_umask@>. This guarantees
+that B<sudo> never lowers the umask when running a command. Note
+on systems that use PAM, the default PAM configuration may specify
+its own umask which will override the value set in I<sudoers>.
=back
B<Strings>:
-=over 12
-
-=item mailsub
-
-Subject of the mail sent to the I<mailto> user. The escape C<%h>
-will expand to the hostname of the machine.
-Default is C<@mailsub@>.
+=over 16
=item badpass_message
Message that is displayed if a user enters an incorrect password.
The default is C<@badpass_message@> unless insults are enabled.
-=item timestampdir
+=item editor
-The directory in which B<sudo> stores its timestamp files.
-The default is F<@timedir@>.
+A colon (':') separated list of editors allowed to be used with
+B<visudo>. B<visudo> will choose the editor that matches the user's
+EDITOR environment variable if possible, or the first editor in the
+list that exists and is executable. The default is C<"@editor@">.
-=item timestampowner
+=item mailsub
-The owner of the timestamp directory and the timestamps stored therein.
-The default is C<root>.
+Subject of the mail sent to the I<mailto> user. The escape C<%h>
+will expand to the host name of the machine.
+Default is C<@mailsub@>.
+
+=item noexec_file
+
+Path to a shared library containing dummy versions of the execv(),
+execve() and fexecve() library functions that just return an error.
+This is used to implement the I<noexec> functionality on systems that
+support C<LD_PRELOAD> or its equivalent. Defaults to F<@noexec_file@>.
=item passprompt
via the B<-p> option or the C<SUDO_PROMPT> environment variable.
The following percent (`C<%>') escapes are supported:
-=over 8
+=over 4
-=item C<%u>
+=item C<%H>
-expanded to the invoking user's login name
+expanded to the local host name including the domain name
+(on if the machine's host name is fully qualified or the I<fqdn>
+option is set)
+
+=item C<%h>
+
+expanded to the local host name without the domain name
+
+=item C<%p>
+
+expanded to the user whose password is being asked for (respects the
+I<rootpw>, I<targetpw> and I<runaspw> flags in I<sudoers>)
=item C<%U>
expanded to the login name of the user the command will
be run as (defaults to root)
-=item C<%h>
-
-expanded to the local hostname without the domain name
-
-=item C<%H>
+=item C<%u>
-expanded to the local hostname including the domain name
-(on if the machine's hostname is fully qualified or the I<fqdn>
-option is set)
+expanded to the invoking user's login name
=item C<%%>
The default value is C<@passprompt@>.
+=item role
+
+The default SELinux role to use when constructing a new security
+context to run the command. The default role may be overridden on
+a per-command basis in I<sudoers> or via command line options.
+This option is only available whe B<sudo> is built with SELinux support.
+
=item runas_default
-The default user to run commands as if the B<-u> flag is not specified
+The default user to run commands as if the B<-u> option is not specified
on the command line. This defaults to C<@runas_default@>.
Note that if I<runas_default> is set it B<must> occur before
any C<Runas_Alias> specifications.
+=item syslog_badpri
+
+Syslog priority to use when user authenticates unsuccessfully.
+Defaults to C<@badpri@>.
+
=item syslog_goodpri
Syslog priority to use when user authenticates successfully.
Defaults to C<@goodpri@>.
-=item syslog_badpri
+=item sudoers_locale
-Syslog priority to use when user authenticates unsuccessfully.
-Defaults to C<@badpri@>.
+Locale to use when parsing the sudoers file. Note that changing
+the locale may affect how sudoers is interpreted.
+Defaults to C<"C">.
-=item editor
+=item timestampdir
-A colon (':') separated list of editors allowed to be used with
-B<visudo>. B<visudo> will choose the editor that matches the user's
-USER environment variable if possible, or the first editor in the
-list that exists and is executable. The default is the path to vi
-on your system.
+The directory in which B<sudo> stores its timestamp files.
+The default is F<@timedir@>.
-=item noexec_file
+=item timestampowner
-Path to a shared library containing dummy versions of the execv(),
-execve() and fexecve() library functions that just return an error.
-This is used to implement the I<noexec> functionality on systems that
-support C<LD_PRELOAD> or its equivalent. Defaults to F<@noexec_file@>.
+The owner of the timestamp directory and the timestamps stored therein.
+The default is C<root>.
+
+=item type
+
+The default SELinux type to use when constructing a new security
+context to run the command. The default type may be overridden on
+a per-command basis in I<sudoers> or via command line options.
+This option is only available whe B<sudo> is built with SELinux support.
=back
=over 12
+=item askpass
+
+The I<askpass> option specifies the fully qualified path to a helper
+program used to read the user's password when no terminal is
+available. This may be the case when B<sudo> is executed from a
+graphical (as opposed to text-based) application. The program
+specified by I<askpass> should display the argument passed to it
+as the prompt and write the user's password to the standard output.
+The value of I<askpass> may be overridden by the C<SUDO_ASKPASS>
+environment variable.
+
+=item env_file
+
+The I<env_file> options 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
+C<VARIABLE=value> or C<export VARIABLE=value>. The value may
+optionally be surrounded by single or double quotes. Variables in
+this file are subject to other B<sudo> environment settings such
+as I<env_keep> and I<env_check>.
+
+=item exempt_group
+
+Users in this group are exempt from password and PATH requirements.
+This is not set by default.
+
=item lecture
This option controls when a short lecture will be printed along with
=over 8
+=item always
+
+Always lecture the user.
+
=item never
Never lecture the user.
Only lecture the user the first time they run B<sudo>.
-=item always
-
-Always lecture the user.
-
=back
If no value is specified, a value of I<once> is implied.
=item lecture_file
-Path to a file containing an alternate sudo lecture that will
+Path to a file containing an alternate B<sudo> lecture that will
be used in place of the standard lecture if the named file exists.
+By default, B<sudo> uses a built-in lecture.
+
+=item listpw
+
+This option controls when a password will be required when a
+user runs B<sudo> with the B<-l> option. It has the following possible values:
+
+=over 8
+
+=item all
+
+All the user's I<sudoers> entries for the current host must have
+the C<NOPASSWD> flag set to avoid entering a password.
+
+=item always
+
+The user must always enter a password to use the B<-l> option.
+
+=item any
+
+At least one of the user's I<sudoers> entries for the current host
+must have the C<NOPASSWD> flag set to avoid entering a password.
+
+=item never
+
+The user need never enter a password to use the B<-l> option.
+
+=back
+
+If no value is specified, a value of I<any> is implied.
+Negating the option results in a value of I<never> being used.
+The default value is I<any>.
=item logfile
Path to the B<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, B<sudo> logs via syslog.
-=item syslog
+=item mailerflags
-Syslog facility if syslog is being used for logging (negate to
-disable syslog logging). Defaults to C<@logfac@>.
+Flags to use when invoking mailer. Defaults to B<-t>.
=item mailerpath
Path to mail program used to send warning mail.
Defaults to the path to sendmail found at configure time.
-=item mailerflags
+=item mailfrom
-Flags to use when invoking mailer. Defaults to B<-t>.
+Address to use for the "from" address when sending warning and error
+mail. The address should be enclosed in double quotes (C<">) to
+protect against B<sudo> interpreting the C<@> sign. Defaults to
+the name of the user running B<sudo>.
=item mailto
Address to send warning and error mail to. The address should
-be enclosed in double quotes (C<">) to protect against sudo
+be enclosed in double quotes (C<">) to protect against B<sudo>
interpreting the C<@> sign. Defaults to C<@mailto@>.
-=item exempt_group
+=item secure_path
-Users in this group are exempt from password and PATH requirements. This
-option is turned on for Debian.
+Path used for every command run from B<sudo>. If you don't trust the
+people running B<sudo> to have a sane C<PATH> environment variable you may
+want to use this. Another use is if you want to have the "root path"
+be separate from the "user path." Users in the group specified by the
+I<exempt_group> option are not affected by I<secure_path>.
+This option is @secure_path@ by default.
+
+=item syslog
+
+Syslog facility if syslog is being used for logging (negate to
+disable syslog logging). Defaults to C<@logfac@>.
=item verifypw
This option controls when a password will be required when a user runs
-B<sudo> with the B<-v> flag. It has the following possible values:
+B<sudo> with the B<-v> option. It has the following possible values:
=over 8
All the user's I<sudoers> entries for the current host must have
the C<NOPASSWD> flag set to avoid entering a password.
-=item any
-
-At least one of the user's I<sudoers> entries for the current host
-must have the C<NOPASSWD> flag set to avoid entering a password.
-
-=item never
-
-The user need never enter a password to use the B<-v> flag.
-
=item always
-The user must always enter a password to use the B<-v> flag.
-
-=back
-
-If no value is specified, a value of I<all> is implied.
-Negating the option results in a value of I<never> being used.
-The default value is I<all>.
-
-=item listpw
-
-This option controls when a password will be required when a
-user runs B<sudo> with the B<-l> flag. It has the following possible values:
-
-=over 8
-
-=item all
-
-All the user's I<sudoers> entries for the current host must have
-the C<NOPASSWD> flag set to avoid entering a password.
+The user must always enter a password to use the B<-v> option.
=item any
=item never
-The user need never enter a password to use the B<-l> flag.
-
-=item always
-
-The user must always enter a password to use the B<-l> flag.
+The user need never enter a password to use the B<-v> option.
=back
-If no value is specified, a value of I<any> is implied.
+If no value is specified, a value of I<all> is implied.
Negating the option results in a value of I<never> being used.
-The default value is I<any>.
+The default value is I<all>.
=back
B<Lists that can be used in a boolean context>:
-=over 12
+=over 16
=item env_check
-Like I<env_keep>, but listed environment variables are taken from the user's environment if
-the variable's value does B<not> contain C<%> or C</> characters. This can
+Environment variables to be removed from the user's environment if
+the variable's value contains C<%> or C</> characters. This can
be used to guard against printf-style format vulnerabilities in
poorly-written programs. 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 C<=>, C<+=>, C<-=>, and C<!> operators respectively. The default
-list of environment variables to check is printed when B<sudo> is
-run by root with the I<-V> option.
+the C<=>, C<+=>, C<-=>, and C<!> operators respectively. Regardless
+of whether the C<env_reset> option is enabled or disabled, variables
+specified by C<env_check> will be preserved in the environment if
+they pass the aforementioned check. The default list of environment
+variables to check is displayed when B<sudo> is run by root with
+the I<-V> option.
=item env_delete
-
-Not effective due to security issues: only variables listed in
-I<env_keep> or I<env_check> can be passed through B<sudo>!
-
-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 C<=>, C<+=>, C<-=>, and
-C<!> operators respectively. The default list of environment
-variables to remove is printed when B<sudo> is run by root with the
-I<-V> option. Note that many operating systems will remove potentially
-dangerous variables from the environment of any setuid process (such
-as B<sudo>).
+Environment variables to be removed from the user's environment
+when the I<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 C<=>, C<+=>, C<-=>, and C<!> operators
+respectively. The default list of environment variables to remove
+is displayed when B<sudo> is run by root with the I<-V> option.
+Note that many operating systems will remove potentially dangerous
+variables from the environment of any setuid process (such as
+B<sudo>).
=item env_keep
-Environment variables to be preserved in the user's environment.
-This allows fine-grained
+Environment variables to be preserved in the user's environment
+when the I<env_reset> option is in effect. This allows fine-grained
control over the environment B<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 C<=>, C<+=>, C<-=>, and
-C<!> operators respectively. This list has no default members.
+C<!> operators respectively. The default list of variables to keep
+is displayed when B<sudo> is run by root with the I<-V> option.
=back
supported: B<alert>, B<crit>, B<debug>, B<emerg>, B<err>, B<info>,
B<notice>, and B<warning>.
-=head2 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? Tag_Spec* Cmnd
-
- Runas_Spec ::= '(' Runas_List ')'
-
- Tag_Spec ::= ('NOPASSWD:' | 'PASSWD:' | 'NOEXEC:' | 'EXEC:')
-
-A B<user specification> determines which commands a user may run
-(and as what user) on specified hosts. By default, commands are
-run as B<root>, but this can be changed on a per-command basis.
-
-Let's break that down into its constituent parts:
-
-=head2 Runas_Spec
-
-A C<Runas_Spec> is simply a C<Runas_List> (as defined above)
-enclosed in a set of parentheses. If you do not specify a
-C<Runas_Spec> in the user specification, a default C<Runas_Spec>
-of B<root> will be used. A C<Runas_Spec> sets the default for
-commands that follow it. What this means is that for the entry:
-
- dgb boulder = (operator) /bin/ls, /bin/kill, /usr/bin/lprm
-
-The user B<dgb> may run F</bin/ls>, F</bin/kill>, and
-F</usr/bin/lprm> -- but only as B<operator>. E.g.,
-
- $ sudo -u operator /bin/ls.
-
-It is also possible to override a C<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 B<dgb> is now allowed to run F</bin/ls> as B<operator>,
-but F</bin/kill> and F</usr/bin/lprm> as B<root>.
-
-=head2 Tag_Spec
-
-A command may have zero or more tags associated with it. There are
-four possible tag values, C<NOPASSWD>, C<PASSWD>, C<NOEXEC>, C<EXEC>.
-Once a tag is set on a C<Cmnd>, subsequent C<Cmnd>s in the
-C<Cmnd_Spec_List>, inherit the tag unless it is overridden by the
-opposite tag (ie: C<PASSWD> overrides C<NOPASSWD> and C<EXEC>
-overrides C<NOEXEC>).
-
-=head3 NOPASSWD and PASSWD
-
-By default, B<sudo> requires that a user authenticate him or herself
-before running a command. This behavior can be modified via the
-C<NOPASSWD> tag. Like a C<Runas_Spec>, the C<NOPASSWD> tag sets
-a default for the commands that follow it in the C<Cmnd_Spec_List>.
-Conversely, the C<PASSWD> tag can be used to reverse things.
-For example:
-
- ray rushmore = NOPASSWD: /bin/kill, /bin/ls, /usr/bin/lprm
-
-would allow the user B<ray> to run F</bin/kill>, F</bin/ls>, and
-F</usr/bin/lprm> as root on the machine rushmore as B<root> without
-authenticating himself. If we only want B<ray> to be able to
-run F</bin/kill> without a password the entry would be:
-
- ray rushmore = NOPASSWD: /bin/kill, PASSWD: /bin/ls, /usr/bin/lprm
-
-Note, however, that the C<PASSWD> tag has no effect on users who are
-in the group specified by the exempt_group option.
-
-By default, if the C<NOPASSWD> tag is applied to any of the entries
-for a user on the current host, he or she will be able to run
-C<sudo -l> without a password. Additionally, a user may only run
-C<sudo -v> without a password if the C<NOPASSWD> tag is present
-for all a user's entries that pertain to the current host.
-This behavior may be overridden via the verifypw and listpw options.
-
-=head3 NOEXEC and EXEC
-
-If sudo has been compiled with I<noexec> support and the underlying
-operating system support it, the C<NOEXEC> tag can be used to prevent
-a dynamically-linked executable from running further commands itself.
-
-In the following example, user B<aaron> may run F</usr/bin/more>
-and F</usr/bin/vi> but shell escapes will be disabled.
-
- aaron shanty = NOEXEC: /usr/bin/more, /usr/bin/vi
-
-See the L<PREVENTING SHELL ESCAPES> section below for more details
-on how I<noexec> works and whether or not it will work on your system.
-
-=head2 Wildcards
-
-B<sudo> allows shell-style I<wildcards> (aka meta or glob characters)
-to be used in pathnames as well as command line arguments in the
-I<sudoers> file. Wildcard matching is done via the B<POSIX>
-L<fnmatch(3)> routine. Note that these are I<not> regular expressions.
-
-=over 8
-
-=item C<*>
-
-Matches any set of zero or more characters.
-
-=item C<?>
-
-Matches any single character.
-
-=item C<[...]>
-
-Matches any character in the specified range.
-
-=item C<[!...]>
-
-Matches any character B<not> in the specified range.
-
-=item C<\x>
-
-For any character "x", evaluates to "x". This is used to
-escape special characters such as: "*", "?", "[", and "}".
-
-=back
-
-Note that a forward slash ('/') will B<not> be matched by
-wildcards used in the pathname. When matching the command
-line arguments, however, a slash B<does> get matched by
-wildcards. This is to make a path like:
-
- /usr/bin/*
-
-match F</usr/bin/who> but not F</usr/bin/X11/xterm>.
-
-WARNING: a pathname with wildcards will B<not> match a user command
-that consists of a relative path. In other words, given the
-following I<sudoers> entry:
-
- billy workstation = /usr/bin/*
-
-user billy will be able to run any command in /usr/bin as root, such
-as F</usr/bin/w>. The following two command will be allowed (the first
-assumes that F</usr/bin> is in the user's path):
+=head1 FILES
- $ sudo w
- $ sudo /usr/bin/w
+=over 24
-However, this will not:
+=item F<@sysconfdir@/sudoers>
- $ cd /usr/bin
- $ sudo ./w
+List of who can run what
-For this reason you should only B<grant> access to commands using
-wildcards and never B<restrict> access using them. This limitation
-will be removed in a future version of B<sudo>.
+=item F</etc/group>
-=head2 Exceptions to wildcard rules
+Local groups file
-The following exceptions apply to the above rules:
+=item F</etc/netgroup>
-=over 8
+List of network groups
-=item C<"">
+=item F</var/log/sudo-io>
-If the empty string C<""> is the only command line argument in the
-I<sudoers> entry it means that command is not allowed to be run
-with B<any> arguments.
+I/O log files
=back
-=head2 Other special characters and reserved words
-
-The pound sign ('#') is used to indicate a comment (unless it
-occurs in the context of a user name and is followed by one or
-more digits, in which case it is treated as a uid). Both the
-comment character and any text after it, up to the end of the line,
-are ignored.
-
-The reserved word B<ALL> is a built-in I<alias> that always causes
-a match to succeed. It can be used wherever one might otherwise
-use a C<Cmnd_Alias>, C<User_Alias>, C<Runas_Alias>, or C<Host_Alias>.
-You should not try to define your own I<alias> called B<ALL> as the
-built-in alias will be used in preference to your own. Please note
-that using B<ALL> can be dangerous since in a command context, it
-allows the user to run B<any> command on the system.
-
-An exclamation point ('!') can be used as a logical I<not> operator
-both in an I<alias> and in front of a C<Cmnd>. This allows one to
-exclude certain values. Note, however, that using a C<!> in
-conjunction with the built-in C<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
-character on the line.
-
-Whitespace between elements in a list as well as special syntactic
-characters in a I<User Specification> ('=', ':', '(', ')') is optional.
-
-The following characters must be escaped with a backslash ('\') when
-used as part of a word (e.g. a username or hostname):
-'@', '!', '=', ':', ',', '(', ')', '\'.
-
-=head1 FILES
-
- @sysconfdir@/sudoers List of who can run what
- /etc/group Local groups file
- /etc/netgroup List of network groups
-
=head1 EXAMPLES
-Since the I<sudoers> file is parsed in a single pass, order is
-important. In general, you should structure I<sudoers> such that
-the C<Host_Alias>, C<User_Alias>, and C<Cmnd_Alias> specifications
-come first, followed by any C<Default_Entry> lines, and finally the
-C<Runas_Alias> and user specifications. The basic rule of thumb
-is you cannot reference an Alias that has not already been defined.
-
Below are example I<sudoers> entries. Admittedly, some of
these are a bit contrived. First, we allow a few environment
variables to pass and then define our I<aliases>:
- # Run X applications through sudo; HOME is used to find .Xauthority file
- # Note that some programs may use HOME for other purposes too and
- # this may lead to privilege escalation!
- Defaults env_keep = "DISPLAY HOME"
-
+ # 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
# 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 :\
/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
B<sudo> to log via L<syslog(3)> using the I<auth> facility in all
cases. We don't want to subject the full time staff to the B<sudo>
lecture, user B<millert> need not give a password, and we don't
-want to reset the C<LOGNAME> or C<USER> environment variables when
-running commands as root. Additionally, on the machines in the
-I<SERVERS> C<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.
+want to reset the C<LOGNAME>, C<USER> or C<USERNAME> environment
+variables when running commands as root. Additionally, on the
+machines in the I<SERVERS> C<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 C<Cmnd_Alias>
+(F</usr/bin/more>, F</usr/bin/pg> and F</usr/bin/less>).
# Override built-in defaults
Defaults syslog=auth
Defaults:FULLTIMERS !lecture
Defaults:millert !authenticate
Defaults@SERVERS log_year, logfile=/var/log/sudo.log
+ Defaults!PAGERS noexec
The I<User specification> is the part that actually determines who may
run what.
The user B<joe> may only L<su(1)> to operator.
- pete HPPA = /usr/bin/passwd [A-z]*, !/usr/bin/passwd root
+ pete HPPA = /usr/bin/passwd [A-Za-z]*, !/usr/bin/passwd root
+
+ %opers ALL = (: ADMINGRP) /usr/sbin/
+
+Users in the B<opers> group may run commands in F</usr/sbin/> as themselves
+with any group in the I<ADMINGRP> C<Runas_Alias> (the B<adm> and B<oper>
+groups).
The user B<pete> is allowed to change anyone's password except for
root on the I<HPPA> machines. Note that this assumes L<passwd(1)>
-does not take multiple usernames on the command line.
+does not take multiple user names on the command line.
bob SPARC = (OP) ALL : SGI = (OP) ALL
jim +biglab = ALL
The user B<jim> may run any command on machines in the I<biglab> netgroup.
-B<Sudo> knows that "biglab" is a netgroup due to the '+' prefix.
+B<sudo> knows that "biglab" is a netgroup due to the '+' prefix.
+secretaries ALL = PRINTING, /usr/bin/adduser, /usr/bin/rmuser
john ALPHA = /usr/bin/su [!-]*, !/usr/bin/su *root*
On the I<ALPHA> machines, user B<john> may su to anyone except root
-but he is not allowed to give L<su(1)> any flags.
+but he is not allowed to specify any options to the L<su(1)> command.
jen ALL, !SERVERS = ALL
jill SERVERS = /usr/bin/, !SU, !SHELLS
For any machine in the I<SERVERS> C<Host_Alias>, B<jill> may run
-any commands in the directory /usr/bin/ except for those commands
+any commands in the directory F</usr/bin/> except for those commands
belonging to the I<SU> and I<SHELLS> C<Cmnd_Aliases>.
steve CSNETS = (operator) /usr/local/op_commands/
program. Therefore, these kind of restrictions should be considered
advisory at best (and reinforced by policy).
+Furthermore, if the I<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
+L<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 I<sudoers> 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 B<john> can still run C</usr/bin/passwd root> if I<fast_glob> is
+enabled by changing to F</usr/bin> and running C<./passwd root> instead.
+
=head1 PREVENTING SHELL ESCAPES
Once B<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 B<sudo>'s restrictions. Common programs
-that permit shell escapes include shells (obviously), editors,
-paginators, mail and terminal programs.
+which lets a user bypass B<sudo>'s access control and logging.
+Common programs that permit shell escapes include shells (obviously),
+editors, paginators, mail and terminal programs.
+
+There are two basic approaches to this problem:
+
+=over 10
+
+=item 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 B<sudoedit> is a better solution to
+running editors via B<sudo>. Due to the large number of programs that
+offer shell escapes, restricting users to the set of programs that
+do not is often unworkable.
+
+=item noexec
Many systems that support shared libraries have the ability to
override default library functions by pointing an environment
variable (usually C<LD_PRELOAD>) to an alternate shared library.
On such systems, B<sudo>'s I<noexec> functionality can be used to
-prevent a program run by sudo from executing any other programs.
+prevent a program run by B<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 emulation are not affected.
then B<sudo> may be able to replace the exec family of functions
in the standard library with its own that simply return an error.
Unfortunately, there is no foolproof way to know whether or not
-I<noexec> will work at compile-time. I<Noexec> should work on
+I<noexec> will work at compile-time. I<noexec> should work on
SunOS, Solaris, *BSD, Linux, IRIX, Tru64 UNIX, MacOS X, and HP-UX
-11.x. It is known B<not> to work on AIX and UnixWare. I<Noexec>
+11.x. It is known B<not> to work on AIX and UnixWare. I<noexec>
is expected to work on most operating systems that support the
C<LD_PRELOAD> environment variable. Check your operating system's
manual pages for the dynamic linker (usually ld.so, ld.so.1, dyld,
whether or not your system is capable of supporting I<noexec> you
can always just try it out and see if it works.
-Note that disabling 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 B<sudoedit>.
+=back
+
+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
+B<sudoedit>.
=head1 SEE ALSO
-L<rsh(1)>, L<su(1)>, L<fnmatch(3)>, L<sudo(@mansectsu@)>, L<visudo(@mansectsu@)>
+L<rsh(1)>, L<su(1)>, L<fnmatch(3)>, L<glob(3)>, L<sudo(8)>, L<visudo(8)>
=head1 CAVEATS
will not run with a syntactically incorrect I<sudoers> file.
When using netgroups of machines (as opposed to users), if you
-store fully qualified hostnames in the netgroup (as is usually the
-case), you either need to have the machine's hostname be fully qualified
+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 C<hostname> command or use the I<fqdn> option in
I<sudoers>.
=head1 SUPPORT
-Commercial support is available for B<sudo>, see
-http://www.sudo.ws/sudo/support.html for details.
-
Limited free support is available via the sudo-users mailing list,
see http://www.sudo.ws/mailman/listinfo/sudo-users to subscribe or
search the archives.
=head1 DISCLAIMER
-B<Sudo> is provided ``AS IS'' and any express or implied warranties,
+B<sudo> is provided ``AS IS'' and any express or implied warranties,
including, but not limited to, the implied warranties of merchantability
and fitness for a particular purpose are disclaimed. See the LICENSE
file distributed with B<sudo> or http://www.sudo.ws/sudo/license.html
projects / debian / sudo / blobdiff