1SUDO.CONF(5) BSD File Formats Manual SUDO.CONF(5)
2
4 sudo.conf — configuration for sudo front-end
5
7 The sudo.conf file is used to configure the sudo front-end. It is used
8 to configure sudo plugins, plugin-agnostic path names, debug flags, and
9 other settings.
10 The sudo.conf file supports the following directives, described in detail
12 below.
13 Plugin an approval, audit, I/O logging, or security policy plugin
15 Path a plugin-agnostic path
17 Set a front-end setting, such as disable_coredump or group_source
19 Debug debug flags to aid in debugging sudo, sudoreplay, visudo, and the
21 sudoers plugin.
22 The pound sign (‘#’) is used to indicate a comment. Both the comment
24 character and any text after it, up to the end of the line, are ignored.
25 Long lines can be continued with a backslash (‘\’) as the last character
27 on the line. Leading white space is removed from the beginning of lines
28 even when a continuation character is used.
29 Non-comment lines that don't begin with Plugin, Path, Debug, or Set are
31 silently ignored.
32 The sudo.conf file is always parsed in the ‘C’ locale.
34 Plugin configuration
36 sudo supports a plugin architecture for security policies and input/out‐
37 put logging. Third parties can develop and distribute their own policy
38 and I/O logging plugins to work seamlessly with the sudo front-end.
39 Plugins are dynamically loaded based on the contents of sudo.conf.
40 A Plugin line consists of the Plugin keyword, followed by the symbol_name
42 and the path to the dynamic shared object that contains the plugin. The
43 symbol_name is the name of the struct approval_plugin, struct
44 audit_plugin, struct io_plugin, or struct policy_plugin defined by the
45 plugin. If a plugin implements multiple plugin types, there must be a
46 Plugin line for each unique symbol name. The path may be fully qualified
47 or relative. If not fully qualified, it is relative to the directory
48 specified by the plugin_dir Path setting, which defaults to
49 /usr/libexec/sudo. In other words:
50 Plugin sudoers_policy sudoers.so
52 is equivalent to:
54 Plugin sudoers_policy /usr/libexec/sudo/sudoers.so
56 If the plugin was compiled statically into the sudo binary instead of be‐
58 ing installed as a dynamic shared object, the path should be specified
59 without a leading directory, as it does not actually exist in the file
60 system. For example:
61 Plugin sudoers_policy sudoers.so
63 Starting with sudo 1.8.5, any additional parameters after the path are
65 passed as arguments to the plugin's open function. For example, to over‐
66 ride the compile-time default sudoers file mode:
67 Plugin sudoers_policy sudoers.so sudoers_mode=0440
69 See the sudoers(5) manual for a list of supported arguments.
71 The same dynamic shared object may contain multiple plugins, each with a
73 different symbol name. The file must be owned by user-ID 0 and only
74 writable by its owner. Because of ambiguities that arise from composite
75 policies, only a single policy plugin may be specified. This limitation
76 does not apply to I/O plugins.
77 If no sudo.conf file is present, or if it contains no Plugin lines, the
79 sudoers plugin will be used as the default security policy, for I/O log‐
80 ging (if enabled by the policy), and for auditing. This is equivalent to
81 the following:
82 Plugin sudoers_policy sudoers.so
84 Plugin sudoers_io sudoers.so
85 Plugin sudoers_audit sudoers.so
86 Starting with sudo version 1.9.1, some of the logging functionality of
88 the sudoers plugin has been moved from the policy plugin to an audit
89 plugin. To maintain compatibility with sudo.conf files from older sudo
90 versions, if sudoers is configured as the security policy, it will be
91 used as an audit plugin as well. This guarantees that the logging behav‐
92 ior will be consistnet with that of sudo versions 1.9.0 and below.
93 For more information on the sudo plugin architecture, see the
95 sudo_plugin(5) manual.
96 Path settings
98 A Path line consists of the Path keyword, followed by the name of the
99 path to set and its value. For example:
100 Path intercept disabled
102 Path noexec /usr/libexec/sudo/sudo_noexec.so
103 Path askpass /usr/X11R6/bin/ssh-askpass
104 If no path name is specified, features relying on the specified setting
106 will be disabled. Disabling Path settings is only supported in sudo ver‐
107 sion 1.8.16 and higher.
108 The following plugin-agnostic paths may be set in the /etc/sudo.conf
110 file:
111 askpass
113 The fully qualified path to a helper program used to read the
114 user's password when no terminal is available. This may be the
115 case when sudo is executed from a graphical (as opposed to text-
116 based) application. The program specified by askpass should dis‐
117 play the argument passed to it as the prompt and write the user's
118 password to the standard output. The value of askpass may be over‐
119 ridden by the SUDO_ASKPASS environment variable.
120 devsearch
122 An ordered, colon-separated search path of directories to look in
123 for device nodes. This is used when mapping the process's tty de‐
124 vice number to a device name on systems that do not provide such a
125 mechanism. Sudo will not recurse into sub-directories. If termi‐
126 nal devices may be located in a sub-directory of /dev, that path
127 must be explicitly listed in devsearch. The default value is
128 /dev/pts:/dev/vt:/dev/term:/dev/zcons:/dev/pty:/dev
129 This option is ignored on systems that support either the devname()
131 or _ttyname_dev() functions, for example BSD, macOS and Solaris.
132 intercept
134 The fully-qualified path to a shared library containing a wrappers
135 for the execve(2), execl(3), execle(3), execlp(3), execv(3),
136 execvp(3), execvpe(3), and system(3) library functions that inter‐
137 cepts attempts to run further commands and performs a policy check
138 before allowing them to be executed. This is used to implement the
139 intercept functionality on systems that support LD_PRELOAD or its
140 equivalent. The default value is disabled.
141 noexec
143 The fully-qualified path to a shared library containing wrappers
144 for the execve(2), execl(3), execle(3), execlp(3), exect(3),
145 execv(3), execveat(3), execvP(3), execvp(3), execvpe(3),
146 fexecve(3), popen(3), posix_spawn(3), posix_spawnp(3), system(3),
147 and wordexp(3) library functions that prevent the execution of fur‐
148 ther commands. This is used to implement the noexec functionality
149 on systems that support LD_PRELOAD or its equivalent. The default
150 value is /usr/libexec/sudo/sudo_noexec.so.
151 plugin_dir
153 The default directory to use when searching for plugins that are
154 specified without a fully qualified path name. The default value
155 is /usr/libexec/sudo.
156 sesh The fully-qualified path to the sesh binary. This setting is only
158 used when sudo is built with SELinux support. The default value is
159 /usr/libexec/sudo/sesh.
160 Other settings
162 The sudo.conf file also supports the following front-end settings:
163 disable_coredump
165 Core dumps of sudo itself are disabled by default to prevent the
166 disclosure of potentially sensitive information. To aid in debug‐
167 ging sudo crashes, you may wish to re-enable core dumps by setting
168 “disable_coredump” to false in sudo.conf as follows:
169 Set disable_coredump false
171 All modern operating systems place restrictions on core dumps from
173 set-user-ID processes like sudo so this option can be enabled with‐
174 out compromising security. To actually get a sudo core file you
175 will likely need to enable core dumps for set-user-ID processes.
176 On BSD and Linux systems this is accomplished in the sysctl(8) com‐
177 mand. On Solaris, the coreadm(1m) command is used to configure
178 core dump behavior.
179 This setting is only available in sudo version 1.8.4 and higher.
181 group_source
183 sudo passes the invoking user's group list to the policy and I/O
184 plugins. On most systems, there is an upper limit to the number of
185 groups that a user may belong to simultaneously (typically 16 for
186 compatibility with NFS). On systems with the getconf(1) utility,
187 running:
188 getconf NGROUPS_MAX
189 will return the maximum number of groups.
190 However, it is still possible to be a member of a larger number of
192 groups--they simply won't be included in the group list returned by
193 the kernel for the user. Starting with sudo version 1.8.7, if the
194 user's kernel group list has the maximum number of entries, sudo
195 will consult the group database directly to determine the group
196 list. This makes it possible for the security policy to perform
197 matching by group name even when the user is a member of more than
198 the maximum number of groups.
199 The group_source setting allows the administrator to change this
201 default behavior. Supported values for group_source are:
202 static
204 Use the static group list that the kernel returns. Retriev‐
205 ing the group list this way is very fast but it is subject to
206 an upper limit as described above. It is “static” in that it
207 does not reflect changes to the group database made after the
208 user logs in. This was the default behavior prior to sudo
209 1.8.7.
210 dynamic
212 Always query the group database directly. It is “dynamic” in
213 that changes made to the group database after the user logs
214 in will be reflected in the group list. On some systems,
215 querying the group database for all of a user's groups can be
216 time consuming when querying a network-based group database.
217 Most operating systems provide an efficient method of per‐
218 forming such queries. Currently, sudo supports efficient
219 group queries on AIX, BSD, HP-UX, Linux, macOS, and Solaris.
220 This is the default behavior on macOS in sudo 1.9.6 and
221 higher.
222 adaptive
224 Only query the group database if the static group list re‐
225 turned by the kernel has the maximum number of entries. This
226 is the default behavior on systems other than macOS in sudo
227 1.8.7 and higher.
228 For example, to cause sudo to only use the kernel's static list of
230 groups for the user:
231 Set group_source static
233 This setting is only available in sudo version 1.8.7 and higher.
235 max_groups
237 The maximum number of user groups to retrieve from the group data‐
238 base. Values less than one or larger than 1024 will be ignored.
239 This setting is only used when querying the group database di‐
240 rectly. It is intended to be used on systems where it is not pos‐
241 sible to detect when the array to be populated with group entries
242 is not sufficiently large. By default, sudo will allocate four
243 times the system's maximum number of groups (see above) and retry
244 with double that number if the group database query fails.
245 This setting is only available in sudo version 1.8.7 and higher.
247 It should not be required in sudo versions 1.8.24 and higher and
248 may be removed in a later release.
249 probe_interfaces
251 By default, sudo will probe the system's network interfaces and
252 pass the IP address of each enabled interface to the policy plugin.
253 This makes it possible for the plugin to match rules based on the
254 IP address without having to query DNS. On Linux systems with a
255 large number of virtual interfaces, this may take a non-negligible
256 amount of time. If IP-based matching is not required, network in‐
257 terface probing can be disabled as follows:
258 Set probe_interfaces false
260 This setting is only available in sudo version 1.8.10 and higher.
262 Debug settings
264 sudo versions 1.8.4 and higher support a flexible debugging framework
265 that can log what sudo is doing internally if there is a problem.
266 A Debug line consists of the Debug keyword, followed by the name of the
268 program, plugin, or shared object to debug, the debug file name, and a
269 comma-separated list of debug flags. The debug flag syntax used by sudo,
270 the sudoers plugin along with its associated programs and shared objects
271 is subsystem@priority but a third-party plugin is free to use a different
272 format so long as it does not include a comma (‘,’).
273 Examples:
275 Debug sudo /var/log/sudo_debug all@warn,plugin@info
277 would log all debugging statements at the warn level and higher in addi‐
279 tion to those at the info level for the plugin subsystem.
280 Debug sudo_intercept.so /var/log/intercept_debug all@debug
282 would log all debugging statements, regardless of level, for the
284 sudo_intercept.so shared library that implements sudo's intercept func‐
285 tionality on some systems.
286 As of sudo 1.8.12, multiple Debug entries may be specified per program.
288 Older versions of sudo only support a single Debug entry per program.
289 Plugin-specific Debug entries are also supported starting with sudo
290 1.8.12 and are matched by either the base name of the plugin that was
291 loaded (for example sudoers.so) or by the plugin's fully-qualified path
292 name. Previously, the sudoers plugin shared the same Debug entry as the
293 sudo front-end and could not be configured separately.
294 The following priorities are supported, in order of decreasing severity:
296 crit, err, warn, notice, diag, info, trace, and debug. Each priority,
297 when specified, also includes all priorities higher than it. For exam‐
298 ple, a priority of notice would include debug messages logged at notice
299 and higher.
300 The priorities trace and debug also include function call tracing which
302 logs when a function is entered and when it returns. For example, the
303 following trace is for the get_user_groups() function located in
304 src/sudo.c:
305 sudo[123] -> get_user_groups @ src/sudo.c:385
307 sudo[123] <- get_user_groups @ src/sudo.c:429 := groups=10,0,5
308 When the function is entered, indicated by a right arrow ‘->’, the pro‐
310 gram, process ID, function, source file, and line number are logged.
311 When the function returns, indicated by a left arrow ‘<-’, the same in‐
312 formation is logged along with the return value. In this case, the re‐
313 turn value is a string.
314 The following subsystems are used by the sudo front-end:
316 all matches every subsystem
318 args command line argument processing
320 conv user conversation
322 edit sudoedit
324 event event subsystem
326 exec command execution
328 main sudo main function
330 netif network interface handling
332 pcomm communication with the plugin
334 plugin plugin configuration
336 pty pseudo-terminal related code
338 selinux SELinux-specific handling
340 util utility functions
342 utmp utmp handling
344 The sudoers(5) plugin includes support for additional subsystems.
346
348 /etc/sudo.conf sudo front-end configuration
349
351 #
352 # Default /etc/sudo.conf file
353 #
354 # Sudo plugins:
355 # Plugin plugin_name plugin_path plugin_options ...
356 #
357 # The plugin_path is relative to /usr/libexec/sudo unless
358 # fully qualified.
359 # The plugin_name corresponds to a global symbol in the plugin
360 # that contains the plugin interface structure.
361 # The plugin_options are optional.
362 #
363 # The sudoers plugin is used by default if no Plugin lines are present.
364 #Plugin sudoers_policy sudoers.so
365 #Plugin sudoers_io sudoers.so
366 #Plugin sudoers_audit sudoers.so
367 #
369 # Sudo askpass:
370 # Path askpass /path/to/askpass
371 #
372 # An askpass helper program may be specified to provide a graphical
373 # password prompt for "sudo -A" support. Sudo does not ship with its
374 # own askpass program but can use the OpenSSH askpass.
375 #
376 # Use the OpenSSH askpass
377 #Path askpass /usr/X11R6/bin/ssh-askpass
378 #
379 # Use the Gnome OpenSSH askpass
380 #Path askpass /usr/libexec/openssh/gnome-ssh-askpass
381 #
383 # Sudo device search path:
384 # Path devsearch /dev/path1:/dev/path2:/dev
385 #
386 # A colon-separated list of paths to check when searching for a user's
387 # terminal device.
388 #
389 #Path devsearch /dev/pts:/dev/vt:/dev/term:/dev/zcons:/dev/pty:/dev
390 #
392 # Sudo command interception:
393 # Path intercept /path/to/sudo_intercept.so
394 #
395 # Path to a shared library containing replacements for the execv()
396 # and execve() library functions that perform a policy check to verify
397 # the command is allowed and simply return an error if not. This is
398 # used to implement the "intercept" functionality on systems that
399 # support LD_PRELOAD or its equivalent.
400 #
401 # The compiled-in value is usually sufficient and should only be changed
402 # if you rename or move the sudo_intercept.so file.
403 #
404 #Path intercept disabled
405 #
407 # Sudo noexec:
408 # Path noexec /path/to/sudo_noexec.so
409 #
410 # Path to a shared library containing replacements for the execv()
411 # family of library functions that just return an error. This is
412 # used to implement the "noexec" functionality on systems that support
413 # LD_PRELOAD or its equivalent.
414 #
415 # The compiled-in value is usually sufficient and should only be changed
416 # if you rename or move the sudo_noexec.so file.
417 #
418 #Path noexec /usr/libexec/sudo/sudo_noexec.so
419 #
421 # Sudo plugin directory:
422 # Path plugin_dir /path/to/plugins
423 #
424 # The default directory to use when searching for plugins that are
425 # specified without a fully qualified path name.
426 #
427 #Path plugin_dir /usr/libexec/sudo
428 #
430 # Core dumps:
431 # Set disable_coredump true|false
432 #
433 # By default, sudo disables core dumps while it is executing (they
434 # are re-enabled for the command that is run).
435 # To aid in debugging sudo problems, you may wish to enable core
436 # dumps by setting "disable_coredump" to false.
437 #
438 #Set disable_coredump false
439 #
441 # User groups:
442 # Set group_source static|dynamic|adaptive
443 #
444 # Sudo passes the user's group list to the policy plugin.
445 # If the user is a member of the maximum number of groups (usually 16),
446 # sudo will query the group database directly to be sure to include
447 # the full list of groups.
448 #
449 # On some systems, this can be expensive so the behavior is configurable.
450 # The "group_source" setting has three possible values:
451 # static - use the user's list of groups returned by the kernel.
452 # dynamic - query the group database to find the list of groups.
453 # adaptive - if user is in less than the maximum number of groups.
454 # use the kernel list, else query the group database.
455 #
456 #Set group_source static
457 #
459 # Sudo interface probing:
460 # Set probe_interfaces true|false
461 #
462 # By default, sudo will probe the system's network interfaces and
463 # pass the IP address of each enabled interface to the policy plugin.
464 # On systems with a large number of virtual interfaces this may take
465 # a noticeable amount of time.
466 #
467 #Set probe_interfaces false
468 #
470 # Sudo debug files:
471 # Debug program /path/to/debug_log subsystem@priority[,subsyste@priority]
472 #
473 # Sudo and related programs support logging debug information to a file.
474 # The program is typically sudo, sudoers.so, sudoreplay, or visudo.
475 #
476 # Subsystems vary based on the program; "all" matches all subsystems.
477 # Priority may be crit, err, warn, notice, diag, info, trace, or debug.
478 # Multiple subsystem@priority may be specified, separated by a comma.
479 #
480 #Debug sudo /var/log/sudo_debug all@debug
481 #Debug sudoers.so /var/log/sudoers_debug all@debug
482
484 sudo_plugin(5), sudoers(5), sudo(8)
485
487 Many people have worked on sudo over the years; this version consists of
488 code written primarily by:
489 Todd C. Miller
491 See the CONTRIBUTORS.md file in the sudo distribution
493 (https://www.sudo.ws/about/contributors/) for an exhaustive list of peo‐
494 ple who have contributed to sudo.
495
497 If you believe you have found a bug in sudo, you can submit a bug report
498 at https://bugzilla.sudo.ws/
499
501 Limited free support is available via the sudo-users mailing list, see
502 https://www.sudo.ws/mailman/listinfo/sudo-users to subscribe or search
503 the archives.
504
506 sudo is provided “AS IS” and any express or implied warranties, includ‐
507 ing, but not limited to, the implied warranties of merchantability and
508 fitness for a particular purpose are disclaimed. See the LICENSE.md file
509 distributed with sudo or https://www.sudo.ws/about/license/ for complete
510 details.
511Sudo 1.9.13p2 January 16, 2023 Sudo 1.9.13p2