symbol ::= definition|
alternate2 ...Each production rule references others and thus makes up a grammar for the language. EBNF also contains the following operators, which many readers will recognize from regular expressions. Do not, however, confuse them with “wildcard” characters, which have different meanings.
Alias ::= 'User_Alias' User_Alias (':' User_Alias)* | 'Runas_Alias' Runas_Alias (':' Runas_Alias)* | 'Host_Alias' Host_Alias (':' Host_Alias)* | 'Cmnd_Alias' Cmnd_Alias (':' Cmnd_Alias)* User_Alias ::= NAME '=' User_List Runas_Alias ::= NAME '=' Runas_List Host_Alias ::= NAME '=' Host_List Cmnd_Alias ::= NAME '=' Cmnd_List NAME ::= [A-Z]([A-Z][0-9]_)*
Alias_Type NAME = item1, item2, ...
NAMEis a string of uppercase letters, numbers, and underscore characters (‘
NAMEmust start with an uppercase letter. It is possible to put several alias definitions of the same type on a single line, joined by a colon (‘
Alias_Type NAME = item1, item2, item3 : NAME = item4, item5
User_List ::= User | User ',' User_List User ::= '!'* user name | '!'* #uid | '!'* %group | '!'* %#gid | '!'* +netgroup | '!'* %:nonunix_group | '!'* %:#nonunix_gid | '!'* User_Alias
User_Listis made up of one or more user names, user ids (prefixed with ‘
#’), system group names and ids (prefixed with ‘
%’ and ‘
%#’ respectively), netgroups (prefixed with ‘
+’), non-Unix group names and IDs (prefixed with ‘
%:’ and ‘
%:#’ respectively) and
User_Aliases. Each list item may be prefixed with zero or more ‘
!’ operators. An odd number of ‘
!’ operators negate the value of the item; an even number just cancel each other out. A
nonunix_gidmay be enclosed in double quotes to avoid the need for escaping special characters. Alternately, special characters may be specified in escaped hex mode, e.g. \x20 for space. When using double quotes, any prefix characters must be included inside the quotes. The actual
nonunix_gidsyntax depends on the underlying implementation. For instance, the QAS AD backend supports the following formats:
\’) to escape spaces and special characters. See Other special characters and reserved words for a list of characters that need to be escaped.
Runas_List ::= Runas_Member | Runas_Member ',' Runas_List Runas_Member ::= '!'* user name | '!'* #uid | '!'* %group | '!'* %#gid | '!'* %:nonunix_group | '!'* %:#nonunix_gid | '!'* +netgroup | '!'* Runas_Alias
Runas_Listis similar to a
User_Listexcept that instead of
User_Aliases it can contain
Runas_Aliases. Note that user names and groups are matched as strings. In other words, two users (groups) with the same uid (gid) are considered to be distinct. If you wish to match all user names with the same uid (e.g. root and toor), you can use a uid instead (#0 in the example given).
Host_List ::= Host | Host ',' Host_List Host ::= '!'* host name | '!'* ip_addr | '!'* network(/netmask)? | '!'* +netgroup | '!'* Host_Alias
Host_Listis 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, 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. 255.255.255.0 or ffff:ffff:ffff:ffff::), or CIDR notation (number of bits, e.g. 24 or 64). A host name may include shell-style wildcards (see the Wildcards section below), but unless the
host namecommand on your machine returns the fully qualified host name, you'll need to use the fqdn option for wildcards to be useful. Note that sudo only inspects actual network interfaces; this means that IP address 127.0.0.1 (localhost) will never match. Also, the host name “localhost” will only match if that is the actual host name, which is usually only the case for non-networked systems.
Cmnd_List ::= Cmnd | Cmnd ',' Cmnd_List command name ::= file name | file name args | file name '""' Cmnd ::= '!'* command name | '!'* directory | '!'* "sudoedit" | '!'* Cmnd_Alias
Cmnd_Listis a list of one or more command names, directories, and other aliases. A command name is a fully qualified file name which may include shell-style wildcards (see the Wildcards section below). A simple file name allows the user to run the command with any arguments he/she wishes. However, you may also specify command line arguments (including wildcards). Alternately, you can specify
""to indicate that the command may only be run without command line arguments. A directory is a fully qualified path name ending in a ‘
/’. When you specify a directory in a
Cmnd_List, the user will be able to run any file within that directory (but not in any sub-directories therein). If a
Cmndhas associated command line arguments, then the arguments in the
Cmndmust match exactly those given by the user on the command line (or match the wildcards if there are any). Note that the following characters must be escaped with a ‘
\’ if they are used in command arguments: ‘
\’. The special command “
sudoedit” is used to permit a user to run sudo with the -e option (or as sudoedit). It may take command line arguments just as a normal command does.
Default_Entrylines. These may affect all users on any host, all users on a specific host, a specific user, a specific command, or commands being run as a specific user. Note that per-command entries may not include command line arguments. If you need to specify arguments, define a
Cmnd_Aliasand reference that instead.
Default_Type ::= 'Defaults' | 'Defaults' '@' Host_List | 'Defaults' ':' User_List | 'Defaults' '!' Cmnd_List | 'Defaults' '>' Runas_List Default_Entry ::= Default_Type Parameter_List Parameter_List ::= Parameter | Parameter ',' Parameter_List Parameter ::= Parameter '=' Value | Parameter '+=' Value | Parameter '-=' Value | '!'* Parameter
!’ operator. Some integer, string and list parameters may also be used in a boolean context to disable them. Values may be enclosed in double quotes ("") when they contain multiple words. Special characters may be escaped with a backslash (‘
\’). Lists have two additional assignment operators,
-=. These operators are used to add to and delete from a list respectively. It is not an error to use the
-=operator to remove an element that does not exist in a list. Defaults entries are parsed in the following order: generic, host and user Defaults first, then runas Defaults and finally command defaults. See SUDOERS OPTIONS for a list of supported Defaults parameters.
User_Spec ::= User_List Host_List '=' Cmnd_Spec_List \ (':' Host_List '=' Cmnd_Spec_List)* Cmnd_Spec_List ::= Cmnd_Spec | Cmnd_Spec ',' Cmnd_Spec_List Cmnd_Spec ::= Runas_Spec? SELinux_Spec? Tag_Spec* Cmnd Runas_Spec ::= '(' Runas_List? (':' Runas_List)? ')' SELinux_Spec ::= ('ROLE=role' | 'TYPE=type') Tag_Spec ::= ('NOPASSWD:' | 'PASSWD:' | 'NOEXEC:' | 'EXEC:' | 'SETENV:' | 'NOSETENV:' | 'LOG_INPUT:' | 'NOLOG_INPUT:' | 'LOG_OUTPUT:' | 'NOLOG_OUTPUT:')
Runas_Specdetermines the user and/or the group that a command may be run as. A fully-specified
Runas_Specconsists of two
Runas_Lists (as defined above) separated by a colon (‘
:’) and enclosed in a set of parentheses. The first
Runas_Listindicates which users the command may be run as via sudo's -u option. The second defines a list of groups that can be specified via sudo's -g option. If both
Runas_Lists are specified, the command may be run with any combination of users and groups listed in their respective
Runas_Lists. If only the first is specified, the command may be run as any user in the list but no -g option may be specified. If the first
Runas_Listis empty but the second is specified, the command may be run as the invoking user with the group set to any listed in the
Runas_List. If no
Runas_Specis specified the command may be run as root and no group may be specified. A
Runas_Specsets 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
$ sudo -u operator /bin/ls
Runas_Speclater on in an entry. If we modify the entry like so:
dgb boulder = (operator) /bin/ls, (root) /bin/kill, /usr/bin/lprm
/bin/lswith either the user or group set to operator:
dgb boulder = (operator : operator) /bin/ls, (root) /bin/kill,\ /usr/bin/lprm
Runas_Specpermits the user to run as command with that group, it does not force the user to do so. If no group is specified on the command line, the command will run with the group listed in the target user's password database entry. The following would all be permitted by the sudoers entry above:
$ sudo -u operator /bin/ls $ sudo -u operator -g operator /bin/ls $ sudo -g operator /bin/ls
tcm boulder = (:dialer) /usr/bin/tip, /usr/bin/cu,\ /usr/local/bin/minicom
$ sudo -g dialer /usr/bin/cu
Runas_Spec, in which case the user may select any combination of users and groups via the -u and -g options. In this example:
alan ALL = (root, bin : operator, system) ALL
NOLOG_OUTPUT. Once a tag is set on a
Cmnds in the
Cmnd_Spec_List, inherit the tag unless it is overridden by the opposite tag (in other words,
EXEC). NOPASSWD and PASSWD By default, sudo requires that a user authenticate him or herself before running a command. This behavior can be modified via the
NOPASSWDtag. Like a
NOPASSWDtag sets a default for the commands that follow it in the
Cmnd_Spec_List. Conversely, the
PASSWDtag can be used to reverse things. For example:
ray rushmore = NOPASSWD: /bin/kill, /bin/ls, /usr/bin/lprm
ray rushmore = NOPASSWD: /bin/kill, PASSWD: /bin/ls, /usr/bin/lprm
PASSWDtag has no effect on users who are in the group specified by the exempt_group option. By default, if the
NOPASSWDtag is applied to any of the entries for a user on the current host, he or she will be able to run “
sudo -l” without a password. Additionally, a user may only run “
sudo -v” without a password if the
NOPASSWDtag 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. NOEXEC and EXEC If sudo has been compiled with noexec support and the underlying operating system supports it, the
NOEXECtag can be used to prevent a dynamically-linked executable from running further commands itself. In the following example, user aaron may run /usr/bin/more and /usr/bin/vi but shell escapes will be disabled.
aaron shanty = NOEXEC: /usr/bin/more, /usr/bin/vi
NOEXECworks and whether or not it will work on your system. SETENV and NOSETENV These tags override the value of the setenv option on a per-command basis. Note that if
SETENVhas been set for a command, the user may disable the env_reset option from the command line via the -E option. Additionally, environment variables set on the command line are not subject to the restrictions imposed by env_check, env_delete, or env_keep. As such, only trusted users should be allowed to set variables in this manner. If the command matched is ALL, the
SETENVtag is implied for that command; this default may be overridden by use of the
NOSETENVtag. LOG_INPUT and NOLOG_INPUT These tags override the value of the log_input option on a per-command basis. For more information, see the description of log_input in the SUDOERS OPTIONS section below. LOG_OUTPUT and NOLOG_OUTPUT These tags override the value of the log_output option on a per-command basis. For more information, see the description of log_output in the SUDOERS OPTIONS section below. glob(3) and fnmatch(3) routines. Note that these are not regular expressions.
[’, and ‘
:’ character has special meaning in sudoers, it must be escaped. For example:
/’) will not be matched by wildcards used in the path name. This is to make a path like:
?’ or ‘
*’ can match multiple words. For example, while a sudoers entry like:
%operator ALL = /bin/cat /var/log/messages*
$ sudo cat /var/log/messages.1
$ sudo cat /var/log/messages /etc/shadow
""is the only command line argument in the sudoers entry it means that command is not allowed to be run with any arguments.
/’) will not be matched by a wildcard.
#includedirdirectives. This can be used, for example, to keep a site-wide sudoers file in addition to a local, per-machine file. For the sake of this example the site-wide sudoers will be /etc/sudoers and the per-machine one will be /etc/sudoers.local. To include /etc/sudoers.local from within /etc/sudoers we would use the following line in /etc/sudoers:
/’, it must be located in the same directory as the sudoers file it was included from. For example, if /etc/sudoers contains the line:
%hescape, signifying the short form of the host name. In other words, if the machine's host name is “xerxes”, then
#includedirdirective can be used to create a sudo.d directory that the system package manager can drop sudoers rules into as part of package installation. For example, given:
~’ or contain a ‘
.’ character to avoid causing problems with package manager or editor temporary/backup files. Files are parsed in sorted lexical order. That is, /etc/sudoers.d/01_first will be parsed before /etc/sudoers.d/10_second. Be aware that because the sorting is lexical, not numeric, /etc/sudoers.d/1_whoops would be loaded after /etc/sudoers.d/10_second. Using a consistent number of leading zeroes in the file names can be used to avoid such problems. Note that unlike files included via
#include, visudo will not edit the files in a
#includedirdirectory unless one of them contains a syntax error. It is still possible to run visudo with the -f flag to edit the files directly.
#’) 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 ALL is a built-in alias that always causes a match to succeed. It can be used wherever one might otherwise use a
Host_Alias. You should not try to define your own alias called ALL as the built-in alias will be used in preference to your own. Please note that using ALL can be dangerous since in a command context, it allows the user to run any command on the system. An exclamation point (‘
!’) can be used as a logical not operator both in an alias and in front of a
Cmnd. This allows one to exclude certain values. Note, however, that using a ‘
!’ in conjunction with the built-in ALL alias to allow a user to run “all but a few” commands rarely works as intended (see SECURITY NOTES below). Long lines can be continued with a backslash (‘
\’) as the last character on the line. White space between elements in a list as well as special syntactic characters in a User Specification (‘
)’) is optional. The following characters must be escaped with a backslash (‘
\’) when used as part of a word (e.g. a user name or host name): ‘
\’. 's behavior can be modified by
Default_Entrylines, as explained earlier. A list of all supported Defaults parameters, grouped by type, are listed below. Boolean Flags:
HOMEenvironment variable to the home directory of the target user (which is root unless the -u option is used). This effectively means that the -H option is always implied. Note that
HOMEis already set when the the env_reset option is enabled, so always_set_home is only effective for configurations where either env_reset is disabled or
HOMEis present in the env_keep list. This flag is off by default.
NOPASSWDtags. This flag is on by default.
VISUALenvironment 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
editorvariable. visudo will then only use the
VISUALif they match a value specified in
editor. This flag is off by default.
SUDO_*variables. Any variables in the caller's environment that match the
env_checklists are then added, followed by any variables present in the file specified by the env_file option (if any). The default contents of the
env_checklists are displayed when sudo is run by root with the -V option. If the secure_path option is set, its value will be used for the
PATHenvironment variable. This flag is on by default.
!’, as such rules can be trivially bypassed. As such, this option should not be used when sudoers contains rules that contain negated path names which include globbing characters. This flag is off by default.
hostnamecommand) does not contain the domain name. In other words, instead of myhost you would use myhost.mydomain.edu. You may still use the short form if you wish (and even mix the two). This option is only effective when the “canonical” host name, as returned by the getaddrinfo() or gethostbyname() function, is a fully-qualified domain name. This is usually the case when the system is configured to use DNS for host name resolution. If the system is configured to use the /etc/hosts file in preference to DNS, the “canonical” host name may not be fully-qualified. The order that sources are queried for hosts name resolution is usually specified in the /etc/nsswitch.conf, /etc/netsvc.conf, /etc/host.conf, or, in some cases, /etc/resolv.conf file. In the /etc/hosts file, the first host name of the entry is considered to be the “canonical” name; subsequent names are aliases that are not used by sudoers. For example, the following hosts file line for the machine “xyzzy” has the fully-qualified domain name as the “canonical” host name, and the short version as an alias.
192.168.1.1 xyzzy.sudo.ws xyzzy
CNAMEentry) due to performance issues and the fact that there is no way to get all aliases from DNS. This flag is off by default.
PATHenvironment variable; the
PATHitself is not modified. This flag is off by default.
cn=defaultssection. This flag is off by default.
TSID=”. Note that user input may contain sensitive information such as passwords (even if they are not echoed to the screen), which will be stored in the log file unencrypted. In most cases, logging the command output via log_output is all that is required.
TSID=”. Output logs may be viewed with the sudoreplay(8) utility, which can also be used to list or search the available logs.
NOEXECtag has been set, unless overridden by a
EXECtag. See the description of NOEXEC and EXEC below as well as the Preventing shell escapes section at the end of this manual. This flag is off by default.
PATHenvironment variable. Some sites may wish to disable this as it could be used to gather information on the location of executables that the normal user does not have access to. The disadvantage is that if the executable is simply not in the user's
PATH, sudo will tell the user that they are not allowed to run it, which can be confusing. This flag is on by default.
sudo sudo /bin/sh”. Note, however, that turning off root_sudo will also prevent root from running sudoedit. Disabling root_sudo provides no real additional security; it exists purely for historical reasons. This flag is on by default.
root) instead of the password of the invoking user. This flag is off by default.
HOMEenvironment variable will be set to the home directory of the target user (which is root unless the -u option is used). This effectively makes the -s option imply -H. Note that
HOMEis already set when the the env_reset option is enabled, so set_home is only effective for configurations where either env_reset is disabled or
HOMEis present in the env_keep list. This flag is off by default.
USERNAMEenvironment variables to the name of the target user (usually root unless the -u option is given). However, since some programs (including the RCS revision control system) use
LOGNAMEto 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 env_reset option has not been disabled, entries in the env_keep list will override the value of set_logname. This flag is on by default.
SHELLenvironment variable if it is set, falling back on the shell listed in the invoking user's /etc/passwd entry if not). This flag is off by default.
root) instead of the password of the invoking user. In addition, the time stamp 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 -u option. This flag is off by default.
--with-logincapoption. This flag is off by default.
ssh somehost sudo ls” since by default, ssh(1) does not allocate a tty when running a command. This flag is off by default.
80(use 0 or negate the option to disable word wrap).
0for no timeout. The timeout may include a fractional component if minute granularity is insufficient, for example
2.5. The default is
2.5. The default is
5. Set this to
0to always prompt for a password. If set to a value less than
0the user's time stamp will never expire. This can be used to allow users to create or delete their own time stamps via “
sudo -v” and “
sudo -k” respectively.
0022. This guarantees that 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 sudoers.
Sorry, try again.unless insults are enabled.
:’) separated list of editors allowed to be used with visudo. visudo will choose the editor that matches the user's
EDITORenvironment variable if possible, or the first editor in the list that exists and is executable. The default is vi.
LOG_OUTPUTtags are present for a command. The default is /var/log/sudo-io.
%hwill expand to the host name of the machine. Default is “
*** SECURITY information for %h ***”.
LD_PRELOADor its equivalent. Defaults to /usr/local/libexec/sudo_noexec.so.
SUDO_PROMPTenvironment variable. The following percent (‘
%’) escape sequences are supported:
%characters are collapsed into a single
alert. The following syslog priorities are supported: alert, crit, debug, emerg, err, info, notice, and warning.
notice. See syslog_badpri for the list of supported syslog priorities.
VARIABLE=value” or “
export VARIABLE=value”. The value may optionally be surrounded by single or double quotes. Variables in this file are subject to other sudo environment settings such as env_keep and env_check.
%prefix. This is not set by default.
NOPASSWDflag set to avoid entering a password.
NOPASSWDflag set to avoid entering a password.
@sign. Defaults to the name of the user running sudo.
@sign. Defaults to
PATHenvironment 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 exempt_group option are not affected by secure_path. This option is not set by default.
auth. The following syslog facilities are supported: authpriv (if your OS supports it), auth, daemon, user, local0, local1, local2, local3, local4, local5, local6, and local7.
NOPASSWDflag set to avoid entering a password.
NOPASSWDflag set to avoid entering a password.
%’ or ‘
/’ 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
!operators respectively. Regardless of whether the
env_resetoption is enabled or disabled, variables specified by
env_checkwill be preserved in the environment if they pass the aforementioned check. The default list of environment variables to check is displayed when sudo is run by root with the -V option.
!operators respectively. The default list of environment variables to remove is displayed when sudo is run by root with the -V option. Note that many operating systems will remove potentially dangerous variables from the environment of any setuid process (such as sudo).
!operators respectively. The default list of variables to keep is displayed when sudo is run by root with the -V option.
# Run X applications through sudo; HOME is used to find the # .Xauthority file. Note that other programs use HOME to find # configuration files and this may lead to privilege escalation! Defaults env_keep += "DISPLAY HOME" # User alias specification User_Alias FULLTIMERS = millert, mikef, dowdy User_Alias PARTTIMERS = bostley, jwfox, crawl User_Alias WEBMASTERS = will, wendy, wim # Runas alias specification Runas_Alias OP = root, operator Runas_Alias DB = oracle, sybase Runas_Alias ADMINGRP = adm, oper # Host alias specification Host_Alias SPARC = bigtime, eclipse, moet, anchor :\ SGI = grolsch, dandelion, black :\ ALPHA = widget, thalamus, foobar :\ HPPA = boa, nag, python Host_Alias CUNETS = 220.127.116.11/255.255.0.0 Host_Alias CSNETS = 18.104.22.168, 22.214.171.124/24, 126.96.36.199 Host_Alias SERVERS = master, mail, www, ns Host_Alias CDROM = orion, perseus, hercules # Cmnd alias specification Cmnd_Alias DUMPS = /usr/bin/mt, /usr/sbin/dump, /usr/sbin/rdump,\ /usr/sbin/restore, /usr/sbin/rrestore Cmnd_Alias KILL = /usr/bin/kill Cmnd_Alias PRINTING = /usr/sbin/lpc, /usr/bin/lprm Cmnd_Alias SHUTDOWN = /usr/sbin/shutdown Cmnd_Alias HALT = /usr/sbin/halt Cmnd_Alias REBOOT = /usr/sbin/reboot Cmnd_Alias SHELLS = /usr/bin/sh, /usr/bin/csh, /usr/bin/ksh,\ /usr/local/bin/tcsh, /usr/bin/rsh,\ /usr/local/bin/zsh Cmnd_Alias SU = /usr/bin/su Cmnd_Alias PAGERS = /usr/bin/more, /usr/bin/pg, /usr/bin/less
USERNAMEenvironment variables when running commands as root. Additionally, on the machines in the SERVERS
Host_Alias, we keep an additional local log file and make sure we log the year in each log line since the log entries will be kept around for several years. Lastly, we disable shell escapes for the commands in the PAGERS
Cmnd_Alias(/usr/bin/more, /usr/bin/pg and /usr/bin/less).
# Override built-in defaults Defaults syslog=auth Defaults>root !set_logname Defaults:FULLTIMERS !lecture Defaults:millert !authenticate Defaults@SERVERS log_year, logfile=/var/log/sudo.log Defaults!PAGERS noexec
root ALL = (ALL) ALL %wheel ALL = (ALL) ALL
FULLTIMERS ALL = NOPASSWD: ALL
PARTTIMERS ALL = ALL
jack CSNETS = ALL
188.8.131.52). Of those networks, only
184.108.40.206has an explicit netmask (in CIDR notation) indicating it is a class C network. For the other networks in CSNETS, the local machine's netmask will be used during matching.
lisa CUNETS = ALL
operator ALL = DUMPS, KILL, SHUTDOWN, HALT, REBOOT, PRINTING,\ sudoedit /etc/printcap, /usr/oper/bin/
joe ALL = /usr/bin/su operator
pete HPPA = /usr/bin/passwd [A-Za-z]*, !/usr/bin/passwd root %opers ALL = (: ADMINGRP) /usr/sbin/
Runas_Alias(the adm and oper groups). The user pete is allowed to change anyone's password except for root on the HPPA machines. Note that this assumes passwd(1) does not take multiple user names on the command line.
bob SPARC = (OP) ALL : SGI = (OP) ALL
Runas_Alias(root and operator.)
jim +biglab = ALL
+secretaries ALL = PRINTING, /usr/bin/adduser, /usr/bin/rmuser
fred ALL = (DB) NOPASSWD: ALL
Runas_Alias(oracle or sybase) without giving a password.
john ALPHA = /usr/bin/su [!-]*, !/usr/bin/su *root*
jen ALL, !SERVERS = ALL
Host_Alias(master, mail, www and ns).
jill SERVERS = /usr/bin/, !SU, !SHELLS
Host_Alias, jill may run any commands in the directory /usr/bin/ except for those commands belonging to the SU and SHELLS
steve CSNETS = (operator) /usr/local/op_commands/
matt valkyrie = KILL
WEBMASTERS www = (www) ALL, (root) /usr/bin/su www
User_Alias(will, wendy, and wim), may run any command as user www (which owns the web pages) or simply su(1) to www.
ALL CDROM = NOPASSWD: /sbin/umount /CDROM,\ /sbin/mount -o nosuidnodev /dev/cd0a /CDROM
Host_Alias(orion, perseus, hercules) without entering a password. This is a bit tedious for users to type, so it is a prime candidate for encapsulating in a shell script.
!’ operator. A user can trivially circumvent this by copying the desired command to a different name and then executing that. For example:
bill ALL = ALL, !SU, !SHELLS
!’ elements in the user specification.
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
/usr/bin/passwd rootif fast_glob is enabled by changing to /usr/bin and running
./passwd rootinstead. '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:
LD_PRELOAD) to an alternate shared library. On such systems, sudo's noexec functionality can be used to prevent a program run by sudo from executing any other programs. Note, however, that this applies only to native dynamically-linked executables. Statically-linked executables and foreign executables running under binary emulation are not affected. The noexec feature is known to work on SunOS, Solaris, *BSD, Linux, IRIX, Tru64 UNIX, MacOS X, HP-UX 11.x and AIX 5.3 and above. It should be supported on most operating systems that support the
LD_PRELOADenvironment variable. Check your operating system's manual pages for the dynamic linker (usually ld.so, ld.so.1, dyld, dld.sl, rld, or loader) to see if
LD_PRELOADis supported. On Solaris 10 and higher, noexec uses Solaris privileges instead of the
LD_PRELOADenvironment variable. To enable noexec for a command, use the
NOEXECtag as documented in the User Specification section above. Here is that example again:
aaron shanty = NOEXEC: /usr/bin/more, /usr/bin/vi
hostnamecommand or use the fqdn option in sudoers. https://www.sudo.ws/sudo/bugs/ https://www.sudo.ws/mailman/listinfo/sudo-users to subscribe or search the archives. https://www.sudo.ws/sudo/license.html for complete details.