-=cut
-Copyright (c) 1994-1996, 1998-2005, 2007
+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
Agency (DARPA) and Air Force Research Laboratory, Air Force
Materiel Command, USAF, under agreement number F39502-99-1-0512.
-$Sudo: sudoers.pod,v 1.95.2.23 2008/01/05 23:59:42 millert Exp $
=pod
=head1 NAME
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.E<nbsp>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 along with the network number,
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 hostname may
+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<hostname> command on your machine returns the fully
-qualified hostname, you'll need to use the I<fqdn> option for
-wildcards to be useful.
+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_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.
-See L</"SUDOERS OPTIONS"> for a list of supported Defaults parameters.
+Defaults entries are parsed in the following order: generic, host
+and user Defaults first, then runas Defaults and finally command
+defaults.
+
+See L<"SUDOERS OPTIONS"> for a list of supported Defaults parameters.
=head2 User Specification
Cmnd_Spec_List ::= Cmnd_Spec |
Cmnd_Spec ',' Cmnd_Spec_List
- Cmnd_Spec ::= Runas_Spec? Tag_Spec* Cmnd
+ Cmnd_Spec ::= Runas_Spec? SELinux_Spec? Tag_Spec* Cmnd
+
+ Runas_Spec ::= '(' Runas_List? (':' Runas_List)? ')'
- Runas_Spec ::= '(' Runas_List ')'
+ SELinux_Spec ::= ('ROLE=role' | 'TYPE=type')
Tag_Spec ::= ('NOPASSWD:' | 'PASSWD:' | 'NOEXEC:' | 'EXEC:' |
- 'SETENV:' | 'NOSETENV:')
+ 'SETENV:' | 'NOSETENV:' | 'LOG_INPUT:' | 'NOLOG_INPUT:' |
+ 'LOG_OUTPUT:' | 'NOLOG_OUTPUT:')
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:
+The basic structure of a user specification is `who = where (as_whom)
+what'. 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:
+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:
dgb boulder = (operator) /bin/ls, /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>.
+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
-six possible tag values, C<NOPASSWD>, C<PASSWD>, C<NOEXEC>, C<EXEC>,
-C<SETENV> and C<NOSETENV>.
-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>).
+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
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
+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:
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<UNSETENV> tag.
+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 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.
+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
=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 pathname. When matching the command
+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:
=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
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 username or hostname):
+used as part of a word (e.g.E<nbsp>a user name or host name):
'@', '!', '=', ':', ',', '(', ')', '\'.
=head1 SUDOERS OPTIONS
explained earlier. A list of all supported Defaults parameters,
grouped by type, are listed below.
-B<Flags>:
+B<Boolean Flags>:
=over 16
=item always_set_home
-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.
+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 closefrom_override
+
+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
=item env_reset
If set, B<sudo> will reset the environment to only contain the
-LOGNAME, SHELL, USER, USERNAME and the C<SUDO_*> variables. Any
+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 B<sudo> was compiled with
-the C<SECURE_PATH> option, its value will be used for the C<PATH>
-environment variable. This flag is I<on> by default.
+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 hostnames in the
+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 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
+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 hostname (as returned by the C<hostname>
+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.
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>).
+flag is I<@ignore_dot@> by default.
=item ignore_local_sudoers
-If set via LDAP, parsing of @sysconfdir@/sudoers will be skipped.
+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 @sysconfdir@/sudoers.
-When this option is present, @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 cn=defaults
-section. This flag is I<off> by default.
+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
=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
=item passprompt_override
The password prompt specified by I<passprompt> will normally only
-be used if the passwod prompt provided by systems such as PAM matches
+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 pwfeedback
+
+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 wish 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 root_sudo
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>.
+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 set_home
-If set and B<sudo> is invoked with the B<-s> flag the C<HOME>
+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> flag imply B<-H>. This flag is I<off> by default.
+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>, C<USER> and C<USERNAME>
environment variables to the name of the target user (usually root
-unless the B<-u> flag is given). However, since some programs
+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<off> by default.
+I<set_logname>. This flag is I<on> by default.
=item setenv
=item shell_noargs
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
+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 targetpw
-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.
-This flag is I<off> by default.
+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.
+
+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=>.
+
+=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. 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.
+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 use_pty
+
+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 visiblepw
+
+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 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
The number of tries a user gets to enter his/her password before
=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.
+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 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
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 the path to vi
-on your system.
+list that exists and is executable. The default is C<"@editor@">.
=item mailsub
Subject of the mail sent to the I<mailto> user. The escape C<%h>
-will expand to the hostname of the machine.
+will expand to the host name of the machine.
Default is C<@mailsub@>.
=item noexec_file
=item C<%H>
-expanded to the local hostname including the domain name
-(on if the machine's hostname is fully qualified or the I<fqdn>
+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 hostname without the domain name
+expanded to the local host name without the domain name
=item C<%p>
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.
Syslog priority to use when user authenticates successfully.
Defaults to C<@goodpri@>.
+=item sudoers_locale
+
+Locale to use when parsing the sudoers file. Note that changing
+the locale may affect how sudoers is interpreted.
+Defaults to C<"C">.
+
=item timestampdir
The directory in which B<sudo> stores its timestamp files.
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
B<Strings that can be used in a boolean context>:
=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.
=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:
+user runs B<sudo> with the B<-l> option. It has the following possible values:
=over 8
=item always
-The user must always enter a password to use the B<-l> flag.
+The user must always enter a password to use the B<-l> option.
=item any
=item never
-The user need never enter a password to use the B<-l> flag.
+The user need never enter a password to use the B<-l> option.
=back
Path to mail program used to send warning mail.
Defaults to the path to sendmail found at configure time.
+=item mailfrom
+
+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 B<sudo>
interpreting the C<@> sign. Defaults to C<@mailto@>.
+=item secure_path
+
+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
=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
=item always
-The user must always enter a password to use the B<-v> flag.
+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<-v> flag.
+The user need never enter a password to use the B<-v> option.
=back
=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
=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 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>).
+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
=head1 FILES
-=over 4
+=over 24
+
+=item F<@sysconfdir@/sudoers>
-=item F<@sysconfdir@/sudoers>C< >
List of who can run what
-=item F</etc/group>C< >
+=item F</etc/group>
+
Local groups file
-=item F</etc/netgroup>C< >
+=item F</etc/netgroup>
+
List of network groups
+=item F</var/log/sudo-io>
+
+I/O log files
+
=back
=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 that 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 :\
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
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
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
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 if often unworkable.
+do not is often unworkable.
=item noexec
=head1 SEE ALSO
-L<rsh(1)>, L<su(1)>, L<fnmatch(3)>, L<sudo(8)>, L<visudo(8)>
+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>.
projects / debian / sudo / blobdiff