1VISUDO(8) BSD System Manager's Manual VISUDO(8)
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4 visudo — edit the sudoers file
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7 visudo [-chqsV] [-f sudoers]
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10 visudo edits the sudoers file in a safe fashion, analogous to vipw(8).
11 visudo locks the sudoers file against multiple simultaneous edits, pro‐
12 vides basic sanity checks, and checks for parse errors. If the sudoers
13 file is currently being edited you will receive a message to try again
14 later.
15 visudo parses the sudoers file after editing and will not save the
17 changes if there is a syntax error. Upon finding an error, visudo will
18 print a message stating the line number(s) where the error occurred and
19 the user will receive the “What now?” prompt. At this point the user may
20 enter ‘e’ to re-edit the sudoers file, ‘x’ to exit without saving the
21 changes, or ‘Q’ to quit and save changes. The ‘Q’ option should be used
22 with extreme caution because if visudo believes there to be a parse
23 error, so will sudo and no one will be able to run sudo again until the
24 error is fixed. If ‘e’ is typed to edit the sudoers file after a parse
25 error has been detected, the cursor will be placed on the line where the
26 error occurred (if the editor supports this feature).
27 There are two sudoers settings that determine which editor visudo will
29 run.
30 editor A colon (‘:’) separated list of editors allowed to be used with
32 visudo. visudo will choose the editor that matches the user's
33 SUDO_EDITOR, VISUAL or EDITOR environment variable if possible,
34 or the first editor in the list that exists and is executable.
35 Note that the SUDO_EDITOR, VISUAL and EDITOR environment vari‐
36 ables are not preserved by default when the env_reset sudoers
37 option is enabled. The default editor path is /bin/vi which
38 can be set at compile time via the --with-editor configure
39 option.
40 env_editor
42 If set, visudo will use the value of the SUDO_EDITOR, VISUAL or
43 EDITOR environment variables before falling back on the default
44 editor list. Note that this may create a security hole as it
45 allows the user to run any arbitrary command as root without
46 logging. A safer alternative is to place a colon-separated
47 list of editors in the editor variable. visudo will then only
48 use SUDO_EDITOR, VISUAL or EDITOR if they match a value speci‐
49 fied in editor. If the env_reset flag is enabled, the
50 SUDO_EDITOR, VISUAL and/or EDITOR environment variables must be
51 present in the env_keep list for the env_editor flag to func‐
52 tion when visudo is invoked via sudo. The default value is on,
53 which can be set at compile time via the --with-env-editor con‐
54 figure option.
55 The options are as follows:
57 -c, --check
59 Enable check-only mode. The existing sudoers file (and any
60 other files it includes) will be checked for syntax errors.
61 If the -f option has not been specified, visudo will also
62 check the sudoers file owner and mode. A message will be
63 printed to the standard output describing the status of
64 sudoers unless the -q option was specified. If the check
65 completes successfully, visudo will exit with a value of 0.
66 If an error is encountered, visudo will exit with a value of
67 1.
68 -f sudoers, --file=sudoers
70 Specify an alternate sudoers file location. With this
71 option, visudo will edit (or check) the sudoers file of your
72 choice, instead of the default, /etc/sudoers. The lock file
73 used is the specified sudoers file with “.tmp” appended to
74 it. In check-only mode only, the argument to -f may be ‘-’,
75 indicating that sudoers will be read from the standard input.
76 Because the policy is evaluated in its entirety, it is not
77 sufficient to check an individual sudoers include file for
78 syntax errors.
79 -h, --help Display a short help message to the standard output and exit.
81 -q, --quiet
83 Enable quiet mode. In this mode details about syntax errors
84 are not printed. This option is only useful when combined
85 with the -c option.
86 -s, --strict
88 Enable strict checking of the sudoers file. If an alias is
89 referenced but not actually defined or if there is a cycle in
90 an alias, visudo will consider this a parse error. Note that
91 it is not possible to differentiate between an alias and a
92 host name or user name that consists solely of uppercase let‐
93 ters, digits, and the underscore (‘_’) character.
94 -V, --version
96 Print the visudo and sudoers grammar versions and exit.
97 Debugging and sudoers plugin arguments
99 visudo versions 1.8.4 and higher support a flexible debugging framework
100 that is configured via Debug lines in the sudo.conf(5) file.
101 Starting with sudo 1.8.12, visudo will also parse the arguments to the
103 sudoers plugin to override the default sudoers path name, UID, GID and
104 file mode. These arguments, if present, should be listed after the path
105 to the plugin (i.e. after sudoers.so). Multiple arguments may be speci‐
106 fied, separated by white space. For example:
107 Plugin sudoers_policy sudoers.so sudoers_mode=0400
109 The following arguments are supported:
111 sudoers_file=pathname
113 The sudoers_file argument can be used to override the default
114 path to the sudoers file.
115 sudoers_uid=uid
117 The sudoers_uid argument can be used to override the default
118 owner of the sudoers file. It should be specified as a numeric
119 user ID.
120 sudoers_gid=gid
122 The sudoers_gid argument can be used to override the default
123 group of the sudoers file. It must be specified as a numeric
124 group ID (not a group name).
125 sudoers_mode=mode
127 The sudoers_mode argument can be used to override the default
128 file mode for the sudoers file. It should be specified as an
129 octal value.
130 For more information on configuring sudo.conf(5), please refer to its
132 manual.
133
135 The following environment variables may be consulted depending on the
136 value of the editor and env_editor sudoers settings:
137 SUDO_EDITOR Invoked by visudo as the editor to use
139 VISUAL Used by visudo if SUDO_EDITOR is not set
141 EDITOR Used by visudo if neither SUDO_EDITOR nor VISUAL is set
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145 /etc/sudo.conf Sudo front end configuration
146 /etc/sudoers List of who can run what
148 /etc/sudoers.tmp Lock file for visudo
150
152 In addition to reporting sudoers parse errors, visudo may produce the
153 following messages:
154 sudoers file busy, try again later.
156 Someone else is currently editing the sudoers file.
157 /etc/sudoers.tmp: Permission denied
159 You didn't run visudo as root.
160 you do not exist in the passwd database
162 Your user ID does not appear in the system passwd database.
163 Warning: {User,Runas,Host,Cmnd}_Alias referenced but not defined
165 Either you are trying to use an undeclared
166 {User,Runas,Host,Cmnd}_Alias or you have a user or host name listed
167 that consists solely of uppercase letters, digits, and the under‐
168 score (‘_’) character. In the latter case, you can ignore the
169 warnings (sudo will not complain). The message is prefixed with
170 the path name of the sudoers file and the line number where the
171 undefined alias was used. In -s (strict) mode these are errors,
172 not warnings.
173 Warning: unused {User,Runas,Host,Cmnd}_Alias
175 The specified {User,Runas,Host,Cmnd}_Alias was defined but never
176 used. The message is prefixed with the path name of the sudoers
177 file and the line number where the unused alias was defined. You
178 may wish to comment out or remove the unused alias.
179 Warning: cycle in {User,Runas,Host,Cmnd}_Alias
181 The specified {User,Runas,Host,Cmnd}_Alias includes a reference to
182 itself, either directly or through an alias it includes. The mes‐
183 sage is prefixed with the path name of the sudoers file and the
184 line number where the cycle was detected. This is only a warning
185 unless visudo is run in -s (strict) mode as sudo will ignore cycles
186 when parsing the sudoers file.
187 unknown defaults entry "name"
189 The sudoers file contains a Defaults setting not recognized by
190 visudo.
191
193 vi(1), sudo.conf(5), sudoers(5), sudo(8), vipw(8)
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196 Many people have worked on sudo over the years; this version consists of
197 code written primarily by:
198 Todd C. Miller
200 See the CONTRIBUTORS file in the sudo distribution
202 (https://www.sudo.ws/contributors.html) for an exhaustive list of people
203 who have contributed to sudo.
204
206 There is no easy way to prevent a user from gaining a root shell if the
207 editor used by visudo allows shell escapes.
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210 If you feel you have found a bug in visudo, please submit a bug report at
211 https://bugzilla.sudo.ws/
212
214 Limited free support is available via the sudo-users mailing list, see
215 https://www.sudo.ws/mailman/listinfo/sudo-users to subscribe or search
216 the archives.
217
219 visudo is provided “AS IS” and any express or implied warranties, includ‐
220 ing, but not limited to, the implied warranties of merchantability and
221 fitness for a particular purpose are disclaimed. See the LICENSE file
222 distributed with sudo or https://www.sudo.ws/license.html for complete
223 details.
224Sudo 1.8.25p1 January 26, 2018 Sudo 1.8.25p1