=cut
-Copyright (c) 1994-1996,1998-2003 Todd C. Miller <Todd.Miller@courtesan.com>
+Copyright (c) 1994-1996, 1998-2005, 2007
+ 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: sudo.pod,v 1.73 2004/09/08 18:34:38 millert Exp $
+$Sudo: sudo.pod,v 1.70.2.18 2007/08/13 16:23:31 millert Exp $
=pod
=head1 NAME
=head1 SYNOPSIS
-B<sudo> B<-K> | B<-L> | B<-V> | B<-h> | B<-k> | B<-l> | B<-v>
+B<sudo> B<-h> | B<-K> | B<-k> | B<-L> | B<-l> | B<-V> | B<-v>
-B<sudo> [B<-HPSb>] S<[B<-a> I<auth_type>]> S<[B<-c> I<class>|I<->]>
-S<[B<-p> I<prompt>]> S<[B<-u> I<username>|I<#uid>]>
-S<{B<-e> file [...] | B<-i> | B<-s> | I<command>}>
+B<sudo> [B<-bEHPS>] S<[B<-a> I<auth_type>]>
+S<[B<-
c> I<class>|I<->]> S<[B<-p> I<prompt>]> S<[B<-u> I<username>|I<#uid>]>
+S<[B<VAR>=I<value>]> S<{B<-i> | B<-s> | I<command>}>
-B<sudoedit> [B<-S>] S<[B<-a> I<auth_type>]>
+B<sudoedit> [B<-S>] S<[B<-a> I<auth_type>]> S<[B<-c> I<class>|I<->]>
S<[B<-p> I<prompt>]> S<[B<-u> I<username>|I<#uid>]>
-file [...]
+file ...
=head1 DESCRIPTION
is implied.
B<sudo> determines who is an authorized user by consulting the file
-F<@sysconfdir@/sudoers>. By giving B<sudo> the B<-v> flag a user
-can update the time stamp without running a I<command.> The password
+F<@sysconfdir@/sudoers>. By giving B<sudo> the B<-v> flag, a user
+can update the time stamp without running a I<command>. The password
prompt itself will also time out if the user's password is not
entered within C<@password_timeout@> minutes (unless overridden via
I<sudoers>).
=over 4
-=item -H
-
-The B<-H> (I<HOME>) option sets the C<HOME> environment variable
-to the homedir of the target user (root by default) as specified
-in passwd(@mansectform@). By default, B<sudo> does not modify C<HOME>
-(see I<set_home> and I<always_set_home> in L<sudoers(@mansectform@)>).
-
-=item -K
-
-The B<-K> (sure I<kill>) option is like B<-k> except that it removes
-the user's timestamp entirely. Like B<-k>, this option does not
-require a password.
-
-=item -L
-
-The B<-L> (I<list> defaults) option will list out the parameters
-that may be set in a I<Defaults> line along with a short description
-for each. This option is useful in conjunction with grep(1).
-
-=item -P
-
-The B<-P> (I<preserve group vector>) option causes B<sudo> to
-preserve the invoking user's group vector unaltered. By default,
-B<sudo> will initialize the group vector to the list of groups the
-target user is in. The real and effective group IDs, however, are
-still set to match the target user.
-
-=item -S
-
-The B<-S> (I<stdin>) option causes B<sudo> to read the password from
-the standard input instead of the terminal device.
-
-=item -V
-
-The B<-V> (I<version>) option causes B<sudo> to print the version
-number and exit. If the invoking user is already root the B<-V>
-option will print out a list of the defaults B<sudo> was compiled
-with as well as the machine's local network addresses.
-
=item -a
The B<-a> (I<authentication type>) option causes B<sudo> to use the
specified authentication type when validating the user, as allowed
-by /etc/login.conf. The system administrator may specify a list
+by F</etc/login.conf>. The system administrator may specify a list
of sudo-specific authentication methods by adding an "auth-sudo"
-entry in /etc/login.conf. This option is only available on systems
-that support BSD authentication where B<sudo> has been configured
-with the --with-bsdauth option.
+entry in F</etc/login.conf>. This option is only available on systems
+that support BSD authentication.
=item -b
The B<-c> (I<class>) option causes B<sudo> to run the specified command
with resources limited by the specified login class. The I<class>
-argument can be either a class name as defined in /etc/login.conf,
+argument can be either a class name as defined in C</etc/login.conf>,
or a single '-' character. Specifying a I<class> of C<-> indicates
that the command should be run restricted by the default login
capabilities for the user the command is run as. If the I<class>
argument specifies an existing user class, the command must be run
as root, or the B<sudo> command must be run from a shell that is already
-root. This option is only available on systems with BSD login classes
-where B<sudo> has been configured with the --with-logincap option.
+root. This option is only available on systems with BSD login classes.
+
+=item -E
+
+The B<-E> (I<preserve> I<environment>) option will override the
+I<env_reset> option in L<sudoers(5)>). It is only
+available when either the matching command has the C<SETENV> tag
+or the I<setenv> option is set in L<sudoers(5)>.
=item -e
the I<sudoers> file. If the user is authorized by I<sudoers>
the following steps are taken:
-=over 8
+=over 4
=item 1.
user will receive a warning and the edited copy will remain in a
temporary file.
+=item -H
+
+The B<-H> (I<HOME>) option sets the C<HOME> environment variable
+to the homedir of the target user (root by default) as specified
+in passwd(5). By default, B<sudo> does not modify C<HOME>
+(see I<set_home> and I<always_set_home> in L<sudoers(5)>).
+
=item -h
The B<-h> (I<help>) option causes B<sudo> to print a usage message and exit.
=item -i
The B<-i> (I<simulate initial login>) option runs the shell specified
-in the L<passwd(@mansectform@)> entry of the user that the command is
+in the L<passwd(5)> entry of the user that the command is
being run as. The command name argument given to the shell begins
-with a C<-> to tell the shell to run as a login shell. B<sudo>
+with a `C<->' to tell the shell to run as a login shell. B<sudo>
attempts to change to that user's home directory before running the
shell. It also initializes the environment, leaving I<TERM>
unchanged, setting I<HOME>, I<SHELL>, I<USER>, I<LOGNAME>, and
the user to run the shell as but will not affect which shell is
actually run.
+=item -K
+
+The B<-K> (sure I<kill>) option is like B<-k> except that it removes
+the user's timestamp entirely. Like B<-k>, this option does not
+require a password.
+
=item -k
The B<-k> (I<kill>) option to B<sudo> invalidates the user's timestamp
-by setting the time on it to the epoch. The next time B<sudo> is
+by setting the time on it to the Epoch. The next time B<sudo> is
run a password will be required. This option does not require a password
and was added to allow a user to revoke B<sudo> permissions from a .logout
file.
+=item -L
+
+The B<-L> (I<list> defaults) option will list out the parameters
+that may be set in a I<Defaults> line along with a short description
+for each. This option is useful in conjunction with L<grep(1)>.
+
=item -l
The B<-l> (I<list>) option will list out the allowed (and
-forbidden) commands for the user on the current host.
+forbidden) commands for the invoking user on the current host.
+
+=item -P
+
+The B<-P> (I<preserve> I<group vector>) option causes B<sudo> to
+preserve the invoking user's group vector unaltered. By default,
+B<sudo> will initialize the group vector to the list of groups the
+target user is in. The real and effective group IDs, however, are
+still set to match the target user.
=item -p
password prompt and use a custom one. 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 hostname including the domain name
+(on if the machine's hostname is fully qualified or the I<fqdn>
+I<sudoers> option is set)
+
+=item C<%h>
+
+expanded to the local hostname without the domain name
=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>
-sudoers option is set)
+expanded to the invoking user's login name
=item C<%%>
=back
+=item -S
+
+The B<-S> (I<stdin>) option causes B<sudo> to read the password from
+the standard input instead of the terminal device.
+
=item -s
The B<-s> (I<shell>) option runs the shell specified by the I<SHELL>
environment variable if it is set or the shell as specified
-in L<passwd(@mansectform@)>.
+in L<passwd(5)>.
=item -u
-The B<-u> (I<user>) option causes B<sudo> to run the specified command
-as a user other than I<root>. To specify a I<uid> instead of a
-I<username>, use I<#uid>. Note that if the I<targetpw> Defaults
-option is set (see L<sudoers(@mansectform@)>) it is not possible
-to run commands with a uid not listed in the password database.
+The B<-u> (I<user>) option causes B<sudo> to run the specified
+command as a user other than I<root>. To specify a I<uid> instead
+of a I<username>, use I<#uid>. When running commands as a I<uid>,
+many shells require that the '#' be escaped with a backslash ('\').
+Note that if the I<targetpw> Defaults option is set (see L<sudoers(5)>)
+it is not possible to run commands with a uid not listed in the
+password database.
+
+=item -V
+
+The B<-V> (I<version>) option causes B<sudo> to print the version
+number and exit. If the invoking user is already root the B<-V>
+option will print out a list of the defaults B<sudo> was compiled
+with as well as the machine's local network addresses.
=item -v
=back
+Environment variables to be set for the command may also be passed
+on the command line in the form of B<VAR>=I<value>, e.g.
+B<LD_LIBRARY_PATH>=I</usr/local/pkg/lib>. Variables passed on the
+command line are subject to the same restrictions as normal environment
+variables with one important exception. If the I<setenv> option
+is set in I<sudoers> or the command to be run has the C<SETENV> tag
+set the user may set variables that would overwise be forbidden.
+See L<sudoers(5)> for more information.
+
=head1 RETURN VALUES
Upon successful execution of a program, the return value from B<sudo>
=head1 SECURITY NOTES
-B<sudo> tries to be safe when executing external commands. Variables
-that control how dynamic loading and binding is done can be used
-to subvert the program that B<sudo> runs. To combat this the
-C<LD_*>, C<_RLD_*>, C<SHLIB_PATH> (HP-UX only), and C<LIBPATH> (AIX
-only) environment variables are removed from the environment passed
-on to all commands executed. B<sudo> will also remove the C<IFS>,
-C<CDPATH>, C<ENV>, C<BASH_ENV>, C<KRB_CONF>, C<KRBCONFDIR>, C<KRBTKFILE>,
-C<KRB5_CONFIG>, C<LOCALDOMAIN>, C<RES_OPTIONS>, C<HOSTALIASES>,
-C<NLSPATH>, C<PATH_LOCALE>, C<TERMINFO>, C<TERMINFO_DIRS> and
-C<TERMPATH> variables as they too can pose a threat. If the
-C<TERMCAP> variable is set and is a pathname, it too is ignored.
-Additionally, if the C<LC_*> or C<LANGUAGE> variables contain the
-C</> or C<%> characters, they are ignored. Environment variables
-with a value beginning with C<()> are also removed as they could
-be interpreted as B<bash> functions. If B<sudo> has been
-compiled with SecurID support, the C<VAR_ACE>, C<USR_ACE> and
-C<DLC_ACE> variables are cleared as well. The list of environment
-variables that B<sudo> clears is contained in the output of
-C<sudo -V> when run as root.
+B<sudo> tries to be safe when executing external commands.
+
+There are two distinct ways to deal with environment variables.
+By default, the I<env_reset> I<sudoers> option is enabled.
+This causes commands to be executed with a minimal environment
+containing C<TERM>, C<PATH>, C<HOME>, C<SHELL>, C<LOGNAME>, C<USER>
+and C<USERNAME> in addition to variables from the invoking process
+permitted by the I<env_check> and I<env_keep> I<sudoers> options.
+There is effectively a whitelist for environment variables.
+
+If, however, the I<env_reset> option is disabled in I<sudoers>, any
+variables not explicitly denied by the I<env_check> and I<env_delete>
+options are inherited from the invoking process. In this case,
+I<env_check> and I<env_delete> behave like a blacklist. Since it
+is not possible to blacklist all potentially dangerous environment
+variables, use of the default I<env_reset> behavior is encouraged.
+
+In all cases, environment variables with a value beginning with
+C<()> are removed as they could be interpreted as B<bash> functions.
+The list of environment variables that B<sudo> allows or denies is
+contained in the output of C<sudo -V> when run as root.
+
+Note that the dynamic linker on most operating systems will remove
+variables that can control dynamic linking from the environment of
+setuid executables, including B<sudo>. Depending on the operating
+system this may include C<_RLD*>, C<DYLD_*>, C<LD_*>, C<LDR_*>,
+C<LIBPATH>, C<SHLIB_PATH>, and others. These type of variables are
+removed from the environment before B<sudo> even begins execution
+and, as such, it is not possible for B<sudo> to preserve them.
To prevent command spoofing, B<sudo> checks "." and "" (both denoting
current directory) last when searching for a command in the user's
actual C<PATH> environment variable is I<not> modified and is passed
unchanged to the program that B<sudo> executes.
-For security reasons, if your OS supports shared libraries and does
-not disable user-defined library search paths for setuid programs
-(most do), you should either use a linker option that disables this
-behavior or link B<sudo> statically.
-
B<sudo> will check the ownership of its timestamp directory
(F<@timedir@> by default) and ignore the directory's contents if
-it is not owned by root and only writable by root. On systems that
-allow non-root users to give away files via L<chown(2)>, if the timestamp
-directory is located in a directory writable by anyone (e.g.: F</tmp>),
-it is possible for a user to create the timestamp directory before
-B<sudo> is run. However, because B<sudo> checks the ownership and
-mode of the directory and its contents, the only damage that can
-be done is to "hide" files by putting them in the timestamp dir.
-This is unlikely to happen since once the timestamp dir is owned
-by root and inaccessible by any other user the user placing files
-there would be unable to get them back out. To get around this
-issue you can use a directory that is not world-writable for the
-timestamps (F</var/adm/sudo> for instance) or create F<@timedir@>
-with the appropriate owner (root) and permissions (0700) in the
-system startup files.
+it is not owned by root or if it is writable by a user other than
+root. On systems that allow non-root users to give away files via
+L<chown(2)>, if the timestamp directory is located in a directory
+writable by anyone (e.g., F</tmp>), it is possible for a user to
+create the timestamp directory before B<sudo> is run. However,
+because B<sudo> checks the ownership and mode of the directory and
+its contents, the only damage that can be done is to "hide" files
+by putting them in the timestamp dir. This is unlikely to happen
+since once the timestamp dir is owned by root and inaccessible by
+any other user, the user placing files there would be unable to get
+them back out. To get around this issue you can use a directory
+that is not world-writable for the timestamps (F</var/adm/sudo> for
+instance) or create F<@timedir@> with the appropriate owner (root)
+and permissions (0700) in the system startup files.
B<sudo> will not honor timestamps set far in the future.
Timestamps with a date greater than current_time + 2 * C<TIMEOUT>
keep a user from creating his/her own timestamp with a bogus
date on systems that allow users to give away files.
-Please note that B<sudo> will only log the command it explicitly
-runs. If a user runs a command such as C<sudo su> or C<sudo sh>,
-subsequent commands run from that shell will I<not> be logged, nor
-will B<sudo>'s access control affect them. The same is true for
-commands that offer shell escapes (including most editors). Because
-of this, care must be taken when giving users access to commands
-via B<sudo> to verify that the command does not inadvertently give
-the user an effective root shell.
+Please note that B<sudo> will normally only log the command it
+explicitly runs. If a user runs a command such as C<sudo su> or
+C<sudo sh>, subsequent commands run from that shell will I<not> be
+logged, nor will B<sudo>'s access control affect them. The same
+is true for commands that offer shell escapes (including most
+editors). Because of this, care must be taken when giving users
+access to commands via B<sudo> to verify that the command does not
+inadvertently give the user an effective root shell. For more
+information, please see the C<PREVENTING SHELL ESCAPES> section in
+L<sudoers(5)>.
=head1 ENVIRONMENT
B<sudo> utilizes the following environment variables:
- EDITOR Default editor to use in -e (sudoedit) mode if
- VISUAL is not set
+=over 16
+
+=item C<EDITOR>
+
+Default editor to use in B<-e> (sudoedit) mode if C<VISUAL> is not set
+
+=item C<HOME>
+
+In B<-s> or B<-H> mode (or if sudo was configured with the
+--enable-shell-sets-home option), set to homedir of the target user
+
+=item C<PATH>
+
+Set to a sane value if the I<secure_path> sudoers option is set.
+
+=item C<SHELL>
- HOME In -s or -H mode (or if sudo was configured with
- the --enable-shell-sets-home option), set to
- homedir of the target user
+Used to determine shell to run with C<-s> option
- PATH Set to a sane value if sudo was configured with
- the --with-secure-path option
+=item C<SUDO_PROMPT>
- SHELL Used to determine shell to run with -s option
+Used as the default password prompt
- SUDO_PROMPT Used as the default password prompt
+=item C<SUDO_COMMAND>
- SUDO_COMMAND Set to the command run by sudo
+Set to the command run by sudo
- SUDO_USER Set to the login of the user who invoked sudo
+=item C<SUDO_USER>
- SUDO_UID Set to the uid of the user who invoked sudo
+Set to the login of the user who invoked sudo
- SUDO_GID Set to the gid of the user who invoked sudo
+=item C<SUDO_UID>
- SUDO_PS1 If set, PS1 will be set to its value
+Set to the uid of the user who invoked sudo
- USER Set to the target user (root unless the -u option
- is specified)
+=item C<SUDO_GID>
- VISUAL Default editor to use in -e (sudoedit) mode
+Set to the gid of the user who invoked sudo
+
+=item C<SUDO_PS1>
+
+If set, C<PS1> will be set to its value
+
+=item C<USER>
+
+Set to the target user (root unless the B<-u> option is specified)
+
+=item C<VISUAL>
+
+Default editor to use in B<-e> (sudoedit) mode
+
+=back
=head1 FILES
- @sysconfdir@/sudoers List of who can run what
- @timedir@ Directory containing timestamps
+=over 4
+
+=item F<@sysconfdir@/sudoers>C< >List of who can run what
+
+=item F<@timedir@>C< >Directory containing timestamps
+
+=back
=head1 EXAMPLES
-Note: the following examples assume suitable L<sudoers(@mansectform@)> entries.
+Note: the following examples assume suitable L<sudoers(5)> entries.
To get a file listing of an unreadable directory:
=head1 SEE ALSO
-L<grep(1)>, L<su(1)>, L<stat(2)>, L<login_cap(3)>, L<sudoers(@mansectform@)>,
-L<passwd(@mansectform@)>, L<visudo(@mansectsu@)>
+L<grep(1)>, L<su(1)>, L<stat(2)>, L<login_cap(3)>, L<passwd(5)>,
+L<sudoers(5)>, L<visudo(8)>
=head1 AUTHORS
Many people have worked on B<sudo> over the years; this
version consists of code written primarily by:
- Todd Miller
+ Todd C. Miller
Chris Jepeway
See the HISTORY file in the B<sudo> distribution or visit
Also, many programs (such as editors) allow the user to run commands
via shell escapes, thus avoiding B<sudo>'s checks. However, on
most systems it is possible to prevent shell escapes with B<sudo>'s
-I<noexec> functionality. See the L<sudoers(@mansectform@)> manual
+I<noexec> functionality. See the L<sudoers(5)> manual
for details.
-It is not meaningful to run the C<cd> command directly via sudo, e.g.
+It is not meaningful to run the C<cd> command directly via sudo, e.g.,
$ sudo cd /usr/local/protected
-since when whe command exits the parent process (your shell) will
+since when the command exits the parent process (your shell) will
still be the same. Please see the EXAMPLES section for more information.
If users have sudo C<ALL> there is nothing to prevent them from
=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