Annotation of embedaddon/sudo/doc/sudo.man.in, revision 1.1.1.1
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151: .IX Title "SUDO @mansectsu@"
152: .TH SUDO @mansectsu@ "September 16, 2011" "1.8.3" "MAINTENANCE COMMANDS"
153: .\" For nroff, turn off justification. Always turn off hyphenation; it makes
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155: .if n .ad l
156: .nh
157: .SH "NAME"
158: sudo, sudoedit \- execute a command as another user
159: .SH "SYNOPSIS"
160: .IX Header "SYNOPSIS"
161: \&\fBsudo\fR [\fB\-D\fR\ \fIlevel\fR] \fB\-h\fR | \fB\-K\fR | \fB\-k\fR | \fB\-V\fR
162: .PP
163: \&\fBsudo\fR \fB\-v\fR [\fB\-AknS\fR]
164: .if \n(BA [\fB\-a\fR\ \fIauth_type\fR]
165: [\fB\-D\fR\ \fIlevel\fR]
166: [\fB\-g\fR\ \fIgroup\ name\fR|\fI#gid\fR] [\fB\-p\fR\ \fIprompt\fR]
167: [\fB\-u\fR\ \fIuser\ name\fR|\fI#uid\fR]
168: .PP
169: \&\fBsudo\fR \fB\-l[l]\fR [\fB\-AknS\fR]
170: .if \n(BA [\fB\-a\fR\ \fIauth_type\fR]
171: [\fB\-D\fR\ \fIlevel\fR]
172: [\fB\-g\fR\ \fIgroup\ name\fR|\fI#gid\fR] [\fB\-p\fR\ \fIprompt\fR]
173: [\fB\-U\fR\ \fIuser\ name\fR] [\fB\-u\fR\ \fIuser\ name\fR|\fI#uid\fR] [\fIcommand\fR]
174: .PP
175: \&\fBsudo\fR [\fB\-AbEHnPS\fR]
176: .if \n(BA [\fB\-a\fR\ \fIauth_type\fR]
177: [\fB\-C\fR\ \fIfd\fR]
178: [\fB\-D\fR\ \fIlevel\fR]
179: .if \n(LC [\fB\-c\fR\ \fIclass\fR|\fI\-\fR]
180: [\fB\-g\fR\ \fIgroup\ name\fR|\fI#gid\fR] [\fB\-p\fR\ \fIprompt\fR]
181: .if \n(SL [\fB\-r\fR\ \fIrole\fR] [\fB\-t\fR\ \fItype\fR]
182: [\fB\-u\fR\ \fIuser\ name\fR|\fI#uid\fR]
183: [\fB\s-1VAR\s0\fR=\fIvalue\fR] [\fB\-i\fR\ |\ \fB\-s\fR] [\fIcommand\fR]
184: .PP
185: \&\fBsudoedit\fR [\fB\-AnS\fR]
186: .if \n(BA [\fB\-a\fR\ \fIauth_type\fR]
187: [\fB\-C\fR\ \fIfd\fR]
188: .if \n(LC [\fB\-c\fR\ \fIclass\fR|\fI\-\fR]
189: [\fB\-D\fR\ \fIlevel\fR]
190: [\fB\-g\fR\ \fIgroup\ name\fR|\fI#gid\fR] [\fB\-p\fR\ \fIprompt\fR]
191: [\fB\-u\fR\ \fIuser\ name\fR|\fI#uid\fR] file ...
192: .SH "DESCRIPTION"
193: .IX Header "DESCRIPTION"
194: \&\fBsudo\fR allows a permitted user to execute a \fIcommand\fR as the
195: superuser or another user, as specified by the security policy.
196: The real and effective uid and gid are set to match those of the
197: target user, as specified in the password database, and the group
198: vector is initialized based on the group database (unless the \fB\-P\fR
199: option was specified).
200: .PP
201: \&\fBsudo\fR supports a plugin architecture for security policies and
202: input/output logging. Third parties can develop and distribute
203: their own policy and I/O logging modules to work seemlessly with
204: the \fBsudo\fR front end. The default security policy is \fIsudoers\fR,
205: which is configured via the file \fI@sysconfdir@/sudoers\fR, or via
206: \&\s-1LDAP\s0. See the \s-1PLUGINS\s0 section for more information.
207: .PP
208: The security policy determines what privileges, if any, a user has
209: to run \fBsudo\fR. The policy may require that users authenticate
210: themselves with a password or another authentication mechanism. If
211: authentication is required, \fBsudo\fR will exit if the user's password
212: is not entered within a configurable time limit. This limit is
213: policy-specific; the default password prompt timeout for the
214: \&\fIsudoers\fR security policy is
215: .ie \n(PT \f(CW\*(C`@password_timeout@\*(C'\fR minutes.
216: .el unlimited.
217: .PP
218: Security policies may support credential caching to allow the user
219: to run \fBsudo\fR again for a period of time without requiring
220: authentication. The \fIsudoers\fR policy caches credentials for
221: \&\f(CW\*(C`@timeout@\*(C'\fR minutes, unless overridden in \fIsudoers\fR\|(@mansectform@). By
222: running \fBsudo\fR with the \fB\-v\fR option, a user can update the cached
223: credentials without running a \fIcommand\fR.
224: .PP
225: When invoked as \fBsudoedit\fR, the \fB\-e\fR option (described below),
226: is implied.
227: .PP
228: Security policies may log successful and failed attempts to use
229: \&\fBsudo\fR. If an I/O plugin is configured, the running command's
230: input and output may be logged as well.
231: .SH "OPTIONS"
232: .IX Header "OPTIONS"
233: \&\fBsudo\fR accepts the following command line options:
234: .IP "\-A" 12
235: .IX Item "-A"
236: Normally, if \fBsudo\fR requires a password, it will read it from the
237: user's terminal. If the \fB\-A\fR (\fIaskpass\fR) option is specified,
238: a (possibly graphical) helper program is executed to read the user's
239: password and output the password to the standard output. If the
240: \&\f(CW\*(C`SUDO_ASKPASS\*(C'\fR environment variable is set, it specifies the path
241: to the helper program. Otherwise, if \fI@sysconfdir@/sudo.conf\fR
242: contains a line specifying the askpass program, that value will be
243: used. For example:
244: .Sp
245: .Vb 2
246: \& # Path to askpass helper program
247: \& Path askpass /usr/X11R6/bin/ssh\-askpass
248: .Ve
249: .Sp
250: If no askpass program is available, sudo will exit with an error.
251: .if \n(BA \{\
252: .IP "\-a \fItype\fR" 12
253: .IX Item "-a type"
254: The \fB\-a\fR (\fIauthentication type\fR) option causes \fBsudo\fR to use the
255: specified authentication type when validating the user, as allowed
256: by \fI/etc/login.conf\fR. The system administrator may specify a list
257: of sudo-specific authentication methods by adding an \*(L"auth-sudo\*(R"
258: entry in \fI/etc/login.conf\fR. This option is only available on systems
259: that support \s-1BSD\s0 authentication.
260: \}
261: .IP "\-b" 12
262: .IX Item "-b"
263: The \fB\-b\fR (\fIbackground\fR) option tells \fBsudo\fR to run the given
264: command in the background. Note that if you use the \fB\-b\fR
265: option you cannot use shell job control to manipulate the process.
266: Most interactive commands will fail to work properly in background
267: mode.
268: .IP "\-C \fIfd\fR" 12
269: .IX Item "-C fd"
270: Normally, \fBsudo\fR will close all open file descriptors other than
271: standard input, standard output and standard error. The \fB\-C\fR
272: (\fIclose from\fR) option allows the user to specify a starting point
273: above the standard error (file descriptor three). Values less than
274: three are not permitted. The security policy may restrict the
275: user's ability to use the \fB\-C\fR option. The \fIsudoers\fR policy only
276: permits use of the \fB\-C\fR option when the administrator has enabled
277: the \fIclosefrom_override\fR option.
278: .if \n(LC \{\
279: .IP "\-c \fIclass\fR" 12
280: .IX Item "-c class"
281: The \fB\-c\fR (\fIclass\fR) option causes \fBsudo\fR to run the specified command
282: with resources limited by the specified login class. The \fIclass\fR
283: argument can be either a class name as defined in \fI/etc/login.conf\fR,
284: or a single '\-' character. Specifying a \fIclass\fR of \f(CW\*(C`\-\*(C'\fR indicates
285: that the command should be run restricted by the default login
286: capabilities for the user the command is run as. If the \fIclass\fR
287: argument specifies an existing user class, the command must be run
288: as root, or the \fBsudo\fR command must be run from a shell that is already
289: root. This option is only available on systems with \s-1BSD\s0 login classes.
290: \}
291: .IP "\-D \fIlevel\fR" 12
292: .IX Item "-D level"
293: Enable debugging of \fBsudo\fR plugins and \fBsudo\fR itself. The \fIlevel\fR
294: may be a value from 1 through 9.
295: .IP "\-E" 12
296: .IX Item "-E"
297: The \fB\-E\fR (\fIpreserve\fR \fIenvironment\fR) option indicates to the
298: security policy that the user wishes to preserve their existing
299: environment variables. The security policy may return an error if
300: the \fB\-E\fR option is specified and the user does not have permission
301: to preserve the environment.
302: .IP "\-e" 12
303: .IX Item "-e"
304: The \fB\-e\fR (\fIedit\fR) option indicates that, instead of running a
305: command, the user wishes to edit one or more files. In lieu of a
306: command, the string \*(L"sudoedit\*(R" is used when consulting the security
307: policy. If the user is authorized by the policy, the following
308: steps are taken:
309: .RS 12
310: .IP "1." 4
311: Temporary copies are made of the files to be edited with the owner
312: set to the invoking user.
313: .IP "2." 4
314: The editor specified by the policy is run to edit the temporary files.
315: The \fIsudoers\fR policy uses the \f(CW\*(C`SUDO_EDITOR\*(C'\fR, \f(CW\*(C`VISUAL\*(C'\fR and \f(CW\*(C`EDITOR\*(C'\fR
316: environment variables (in that order). If none of \f(CW\*(C`SUDO_EDITOR\*(C'\fR,
317: \&\f(CW\*(C`VISUAL\*(C'\fR or \f(CW\*(C`EDITOR\*(C'\fR are set, the first program listed in the
318: \&\fIeditor\fR \fIsudoers\fR\|(@mansectform@) option is used.
319: .IP "3." 4
320: If they have been modified, the temporary files are copied back to
321: their original location and the temporary versions are removed.
322: .RE
323: .RS 12
324: .Sp
325: If the specified file does not exist, it will be created. Note
326: that unlike most commands run by \fBsudo\fR, the editor is run with
327: the invoking user's environment unmodified. If, for some reason,
328: \&\fBsudo\fR is unable to update a file with its edited version, the
329: user will receive a warning and the edited copy will remain in a
330: temporary file.
331: .RE
332: .IP "\-g \fIgroup\fR" 12
333: .IX Item "-g group"
334: Normally, \fBsudo\fR runs a command with the primary group set to the
335: one specified by the password database for the user the command is
336: being run as (by default, root). The \fB\-g\fR (\fIgroup\fR) option causes
337: \&\fBsudo\fR to run the command with the primary group set to \fIgroup\fR
338: instead. To specify a \fIgid\fR instead of a \fIgroup name\fR, use
339: \&\fI#gid\fR. When running commands as a \fIgid\fR, many shells require
340: that the '#' be escaped with a backslash ('\e'). If no \fB\-u\fR option
341: is specified, the command will be run as the invoking user (not
342: root). In either case, the primary group will be set to \fIgroup\fR.
343: .IP "\-H" 12
344: .IX Item "-H"
345: The \fB\-H\fR (\fI\s-1HOME\s0\fR) option requests that the security policy set
346: the \f(CW\*(C`HOME\*(C'\fR environment variable to the home directory of the target
347: user (root by default) as specified by the password database.
348: Depending on the policy, this may be the default behavior.
349: .IP "\-h" 12
350: .IX Item "-h"
351: The \fB\-h\fR (\fIhelp\fR) option causes \fBsudo\fR to print a short help message
352: to the standard output and exit.
353: .IP "\-i [command]" 12
354: .IX Item "-i [command]"
355: The \fB\-i\fR (\fIsimulate initial login\fR) option runs the shell specified
356: by the password database entry of the target user as a login shell.
357: This means that login-specific resource files such as \f(CW\*(C`.profile\*(C'\fR
358: or \f(CW\*(C`.login\*(C'\fR will be read by the shell. If a command is specified,
359: it is passed to the shell for execution via the shell's \fB\-c\fR option.
360: If no command is specified, an interactive shell is executed.
361: \&\fBsudo\fR attempts to change to that user's home directory before
362: running the shell. The security policy shall initialize the
363: environment to a minimal set of variables, similar to what is present
364: when a user logs in. The \fICommand Environment\fR section in the
365: \&\fIsudoers\fR\|(@mansectform@) manual documents how the \fB\-i\fR option affects the
366: environment in which a command is run when the \fIsudoers\fR policy
367: is in use.
368: .IP "\-K" 12
369: .IX Item "-K"
370: The \fB\-K\fR (sure \fIkill\fR) option is like \fB\-k\fR except that it removes
371: the user's cached credentials entirely and may not be used in
372: conjunction with a command or other option. This option does not
373: require a password. Not all security policies support credential
374: caching.
375: .IP "\-k [command]" 12
376: .IX Item "-k [command]"
377: When used alone, the \fB\-k\fR (\fIkill\fR) option to \fBsudo\fR invalidates
378: the user's cached credentials. The next time \fBsudo\fR is run a
379: password will be required. This option does not require a password
380: and was added to allow a user to revoke \fBsudo\fR permissions from a
381: \&.logout file. Not all security policies support credential
382: caching.
383: .Sp
384: When used in conjunction with a command or an option that may require
385: a password, the \fB\-k\fR option will cause \fBsudo\fR to ignore the user's
386: cached credentials. As a result, \fBsudo\fR will prompt for a password
387: (if one is required by the security policy) and will not update the
388: user's cached credentials.
389: .IP "\-l[l] [\fIcommand\fR]" 12
390: .IX Item "-l[l] [command]"
391: If no \fIcommand\fR is specified, the \fB\-l\fR (\fIlist\fR) option will list
392: the allowed (and forbidden) commands for the invoking user (or the
393: user specified by the \fB\-U\fR option) on the current host. If a
394: \&\fIcommand\fR is specified and is permitted by the security policy,
395: the fully-qualified path to the command is displayed along with any
396: command line arguments. If \fIcommand\fR is specified but not allowed,
397: \&\fBsudo\fR will exit with a status value of 1. If the \fB\-l\fR option
398: is specified with an \fBl\fR argument (i.e. \fB\-ll\fR), or if \fB\-l\fR is
399: specified multiple times, a longer list format is used.
400: .IP "\-n" 12
401: .IX Item "-n"
402: The \fB\-n\fR (\fInon-interactive\fR) option prevents \fBsudo\fR from prompting
403: the user for a password. If a password is required for the command
404: to run, \fBsudo\fR will display an error messages and exit.
405: .IP "\-P" 12
406: .IX Item "-P"
407: The \fB\-P\fR (\fIpreserve\fR \fIgroup vector\fR) option causes \fBsudo\fR to
408: preserve the invoking user's group vector unaltered. By default,
409: the \fIsudoers\fR policy will initialize the group vector to the list
410: of groups the target user is in. The real and effective group IDs,
411: however, are still set to match the target user.
412: .IP "\-p \fIprompt\fR" 12
413: .IX Item "-p prompt"
414: The \fB\-p\fR (\fIprompt\fR) option allows you to override the default
415: password prompt and use a custom one. The following percent (`\f(CW\*(C`%\*(C'\fR')
416: escapes are supported by the \fIsudoers\fR policy:
417: .RS 12
418: .ie n .IP "%H" 4
419: .el .IP "\f(CW%H\fR" 4
420: .IX Item "%H"
421: expanded to the host name including the domain name (on if
422: the machine's host name is fully qualified or the \fIfqdn\fR option
423: is set in \fIsudoers\fR\|(@mansectform@))
424: .ie n .IP "%h" 4
425: .el .IP "\f(CW%h\fR" 4
426: .IX Item "%h"
427: expanded to the local host name without the domain name
428: .ie n .IP "%p" 4
429: .el .IP "\f(CW%p\fR" 4
430: .IX Item "%p"
431: expanded to the name of the user whose password is being requested
432: (respects the \fIrootpw\fR, \fItargetpw\fR and \fIrunaspw\fR flags in
433: \&\fIsudoers\fR\|(@mansectform@))
434: .ie n .IP "%U" 4
435: .el .IP "\f(CW%U\fR" 4
436: .IX Item "%U"
437: expanded to the login name of the user the command will be run as
438: (defaults to root unless the \f(CW\*(C`\-u\*(C'\fR option is also specified)
439: .ie n .IP "%u" 4
440: .el .IP "\f(CW%u\fR" 4
441: .IX Item "%u"
442: expanded to the invoking user's login name
443: .ie n .IP "\*(C`%%\*(C'" 4
444: .el .IP "\f(CW\*(C`%%\*(C'\fR" 4
445: .IX Item "%%"
446: two consecutive \f(CW\*(C`%\*(C'\fR characters are collapsed into a single \f(CW\*(C`%\*(C'\fR character
447: .RE
448: .RS 12
449: .Sp
450: The prompt specified by the \fB\-p\fR option will override the system
451: password prompt on systems that support \s-1PAM\s0 unless the
452: \&\fIpassprompt_override\fR flag is disabled in \fIsudoers\fR.
453: .RE
454: .if \n(SL \{\
455: .IP "\-r \fIrole\fR" 12
456: .IX Item "-r role"
457: The \fB\-r\fR (\fIrole\fR) option causes the new (SELinux) security context to
458: have the role specified by \fIrole\fR.
459: \}
460: .IP "\-S" 12
461: .IX Item "-S"
462: The \fB\-S\fR (\fIstdin\fR) option causes \fBsudo\fR to read the password from
463: the standard input instead of the terminal device. The password must
464: be followed by a newline character.
465: .IP "\-s [command]" 12
466: .IX Item "-s [command]"
467: The \fB\-s\fR (\fIshell\fR) option runs the shell specified by the \fI\s-1SHELL\s0\fR
468: environment variable if it is set or the shell as specified in the
469: password database. If a command is specified, it is passed to the
470: shell for execution via the shell's \fB\-c\fR option. If no command
471: is specified, an interactive shell is executed.
472: .if \n(SL \{\
473: .IP "\-t \fItype\fR" 12
474: .IX Item "-t type"
475: The \fB\-t\fR (\fItype\fR) option causes the new (SELinux) security context to
476: have the type specified by \fItype\fR. If no type is specified, the default
477: type is derived from the specified role.
478: \}
479: .IP "\-U \fIuser\fR" 12
480: .IX Item "-U user"
481: The \fB\-U\fR (\fIother user\fR) option is used in conjunction with the
482: \&\fB\-l\fR option to specify the user whose privileges should be listed.
483: The security policy may restrict listing other users' privileges.
484: The \fIsudoers\fR policy only allows root or a user with the \f(CW\*(C`ALL\*(C'\fR
485: privilege on the current host to use this option.
486: .IP "\-u \fIuser\fR" 12
487: .IX Item "-u user"
488: The \fB\-u\fR (\fIuser\fR) option causes \fBsudo\fR to run the specified
489: command as a user other than \fIroot\fR. To specify a \fIuid\fR instead
490: of a \fIuser name\fR, use \fI#uid\fR. When running commands as a \fIuid\fR,
491: many shells require that the '#' be escaped with a backslash ('\e').
492: Security policies may restrict \fIuid\fRs to those listed in the
493: password database. The \fIsudoers\fR policy allows \fIuid\fRs that are
494: not in the password database as long as the \fItargetpw\fR option is
495: not set. Other security policies may not support this.
496: .IP "\-V" 12
497: .IX Item "-V"
498: The \fB\-V\fR (\fIversion\fR) option causes \fBsudo\fR to print its version
499: string and the version string of the security policy plugin and any
500: I/O plugins. If the invoking user is already root the \fB\-V\fR option
501: will display the arguments passed to configure when \fIsudo\fR was
502: built and plugins may display more verbose information such as
503: default options.
504: .IP "\-v" 12
505: .IX Item "-v"
506: When given the \fB\-v\fR (\fIvalidate\fR) option, \fBsudo\fR will update the
507: user's cached credentials, authenticating the user's password if
508: necessary. For the \fIsudoers\fR plugin, this extends the \fBsudo\fR
509: timeout for another \f(CW\*(C`@timeout@\*(C'\fR minutes (or whatever the timeout
510: is set to in \fIsudoers\fR) but does not run a command. Not all
511: security policies support cached credentials.
512: .IP "\-\-" 12
513: The \fB\-\-\fR option indicates that \fBsudo\fR should stop processing command
514: line arguments.
515: .PP
516: Environment variables to be set for the command may also be passed
517: on the command line in the form of \fB\s-1VAR\s0\fR=\fIvalue\fR, e.g.
518: \&\fB\s-1LD_LIBRARY_PATH\s0\fR=\fI/usr/local/pkg/lib\fR. Variables passed on the
519: command line are subject to the same restrictions as normal environment
520: variables with one important exception. If the \fIsetenv\fR option
521: is set in \fIsudoers\fR, the command to be run has the \f(CW\*(C`SETENV\*(C'\fR tag
522: set or the command matched is \f(CW\*(C`ALL\*(C'\fR, the user may set variables
523: that would overwise be forbidden. See \fIsudoers\fR\|(@mansectform@) for more information.
524: .SH "PLUGINS"
525: .IX Header "PLUGINS"
526: Plugins are dynamically loaded based on the contents of the
527: \&\fI@sysconfdir@/sudo.conf\fR file. If no \fI@sysconfdir@/sudo.conf\fR
528: file is present, or it contains no \f(CW\*(C`Plugin\*(C'\fR lines, \fBsudo\fR
529: will use the traditional \fIsudoers\fR security policy and I/O logging,
530: which corresponds to the following \fI@sysconfdir@/sudo.conf\fR file.
531: .PP
532: .Vb 10
533: \& #
534: \& # Default @sysconfdir@/sudo.conf file
535: \& #
536: \& # Format:
537: \& # Plugin plugin_name plugin_path
538: \& # Path askpass /path/to/askpass
539: \& # Path noexec /path/to/noexec.so
540: \& #
541: \& # The plugin_path is relative to @prefix@/libexec unless
542: \& # fully qualified.
543: \& # The plugin_name corresponds to a global symbol in the plugin
544: \& # that contains the plugin interface structure.
545: \& #
546: \& Plugin policy_plugin sudoers.so
547: \& Plugin io_plugin sudoers.so
548: .Ve
549: .PP
550: A \f(CW\*(C`Plugin\*(C'\fR line consists of the \f(CW\*(C`Plugin\*(C'\fR keyword, followed by the
551: \&\fIsymbol_name\fR and the \fIpath\fR to the shared object containing the
552: plugin. The \fIsymbol_name\fR is the name of the \f(CW\*(C`struct policy_plugin\*(C'\fR
553: or \f(CW\*(C`struct io_plugin\*(C'\fR in the plugin shared object. The \fIpath\fR
554: may be fully qualified or relative. If not fully qualified it is
555: relative to the \fI@prefix@/libexec\fR directory. Any additional
556: parameters after the \fIpath\fR are ignored. Lines that don't begin
557: with \f(CW\*(C`Plugin\*(C'\fR or \f(CW\*(C`Path\*(C'\fR are silently ignored
558: .PP
559: For more information, see the \fIsudo_plugin\fR\|(@mansectsu@) manual.
560: .SH "PATHS"
561: .IX Header "PATHS"
562: A \f(CW\*(C`Path\*(C'\fR line consists of the \f(CW\*(C`Path\*(C'\fR keyword, followed by the
563: name of the path to set and its value. E.g.
564: .PP
565: .Vb 2
566: \& Path noexec @noexec_file@
567: \& Path askpass /usr/X11R6/bin/ssh\-askpass
568: .Ve
569: .PP
570: The following plugin-agnostic paths may be set in the
571: \&\fI@sysconfdir@/sudo.conf\fR file.
572: .IP "askpass" 16
573: .IX Item "askpass"
574: The fully qualified path to a helper program used to read the user's
575: password when no terminal is available. This may be the case when
576: \&\fBsudo\fR is executed from a graphical (as opposed to text-based)
577: application. The program specified by \fIaskpass\fR should display
578: the argument passed to it as the prompt and write the user's password
579: to the standard output. The value of \fIaskpass\fR may be overridden
580: by the \f(CW\*(C`SUDO_ASKPASS\*(C'\fR environment variable.
581: .IP "noexec" 16
582: .IX Item "noexec"
583: The fully-qualified path to a shared library containing dummy
584: versions of the \fIexecv()\fR, \fIexecve()\fR and \fIfexecve()\fR library functions
585: that just return an error. This is used to implement the \fInoexec\fR
586: functionality on systems that support \f(CW\*(C`LD_PRELOAD\*(C'\fR or its equivalent.
587: Defaults to \fI@noexec_file@\fR.
588: .SH "RETURN VALUES"
589: .IX Header "RETURN VALUES"
590: Upon successful execution of a program, the exit status from \fBsudo\fR
591: will simply be the exit status of the program that was executed.
592: .PP
593: Otherwise, \fBsudo\fR exits with a value of 1 if there is a
594: configuration/permission problem or if \fBsudo\fR cannot execute the
595: given command. In the latter case the error string is printed to
596: the standard error. If \fBsudo\fR cannot \fIstat\fR\|(2) one or more entries
597: in the user's \f(CW\*(C`PATH\*(C'\fR, an error is printed on stderr. (If the
598: directory does not exist or if it is not really a directory, the
599: entry is ignored and no error is printed.) This should not happen
600: under normal circumstances. The most common reason for \fIstat\fR\|(2)
601: to return \*(L"permission denied\*(R" is if you are running an automounter
602: and one of the directories in your \f(CW\*(C`PATH\*(C'\fR is on a machine that is
603: currently unreachable.
604: .SH "SECURITY NOTES"
605: .IX Header "SECURITY NOTES"
606: \&\fBsudo\fR tries to be safe when executing external commands.
607: .PP
608: To prevent command spoofing, \fBsudo\fR checks \*(L".\*(R" and "" (both denoting
609: current directory) last when searching for a command in the user's
610: \&\s-1PATH\s0 (if one or both are in the \s-1PATH\s0). Note, however, that the
611: actual \f(CW\*(C`PATH\*(C'\fR environment variable is \fInot\fR modified and is passed
612: unchanged to the program that \fBsudo\fR executes.
613: .PP
614: Please note that \fBsudo\fR will normally only log the command it
615: explicitly runs. If a user runs a command such as \f(CW\*(C`sudo su\*(C'\fR or
616: \&\f(CW\*(C`sudo sh\*(C'\fR, subsequent commands run from that shell are not subject
617: to \fBsudo\fR's security policy. The same is true for commands that
618: offer shell escapes (including most editors). If I/O logging is
619: enabled, subsequent commands will have their input and/or output
620: logged, but there will not be traditional logs for those commands.
621: Because of this, care must be taken when giving users access to
622: commands via \fBsudo\fR to verify that the command does not inadvertently
623: give the user an effective root shell. For more information, please
624: see the \f(CW\*(C`PREVENTING SHELL ESCAPES\*(C'\fR section in \fIsudoers\fR\|(@mansectform@).
625: .SH "ENVIRONMENT"
626: .IX Header "ENVIRONMENT"
627: \&\fBsudo\fR utilizes the following environment variables. The security
628: policy has control over the content of the command's environment.
629: .ie n .IP "\*(C`EDITOR\*(C'" 16
630: .el .IP "\f(CW\*(C`EDITOR\*(C'\fR" 16
631: .IX Item "EDITOR"
632: Default editor to use in \fB\-e\fR (sudoedit) mode if neither \f(CW\*(C`SUDO_EDITOR\*(C'\fR
633: nor \f(CW\*(C`VISUAL\*(C'\fR is set
634: .ie n .IP "\*(C`MAIL\*(C'" 16
635: .el .IP "\f(CW\*(C`MAIL\*(C'\fR" 16
636: .IX Item "MAIL"
637: In \fB\-i\fR mode or when \fIenv_reset\fR is enabled in \fIsudoers\fR, set
638: to the mail spool of the target user
639: .ie n .IP "\*(C`HOME\*(C'" 16
640: .el .IP "\f(CW\*(C`HOME\*(C'\fR" 16
641: .IX Item "HOME"
642: Set to the home directory of the target user if \fB\-i\fR or \fB\-H\fR are
643: specified, \fIenv_reset\fR or \fIalways_set_home\fR are set in \fIsudoers\fR,
644: or when the \fB\-s\fR option is specified and \fIset_home\fR is set in
645: \&\fIsudoers\fR
646: .ie n .IP "\*(C`PATH\*(C'" 16
647: .el .IP "\f(CW\*(C`PATH\*(C'\fR" 16
648: .IX Item "PATH"
649: May be overridden by the security policy.
650: .ie n .IP "\*(C`SHELL\*(C'" 16
651: .el .IP "\f(CW\*(C`SHELL\*(C'\fR" 16
652: .IX Item "SHELL"
653: Used to determine shell to run with \f(CW\*(C`\-s\*(C'\fR option
654: .ie n .IP "\*(C`SUDO_ASKPASS\*(C'" 16
655: .el .IP "\f(CW\*(C`SUDO_ASKPASS\*(C'\fR" 16
656: .IX Item "SUDO_ASKPASS"
657: Specifies the path to a helper program used to read the password
658: if no terminal is available or if the \f(CW\*(C`\-A\*(C'\fR option is specified.
659: .ie n .IP "\*(C`SUDO_COMMAND\*(C'" 16
660: .el .IP "\f(CW\*(C`SUDO_COMMAND\*(C'\fR" 16
661: .IX Item "SUDO_COMMAND"
662: Set to the command run by sudo
663: .ie n .IP "\*(C`SUDO_EDITOR\*(C'" 16
664: .el .IP "\f(CW\*(C`SUDO_EDITOR\*(C'\fR" 16
665: .IX Item "SUDO_EDITOR"
666: Default editor to use in \fB\-e\fR (sudoedit) mode
667: .ie n .IP "\*(C`SUDO_GID\*(C'" 16
668: .el .IP "\f(CW\*(C`SUDO_GID\*(C'\fR" 16
669: .IX Item "SUDO_GID"
670: Set to the group \s-1ID\s0 of the user who invoked sudo
671: .ie n .IP "\*(C`SUDO_PROMPT\*(C'" 16
672: .el .IP "\f(CW\*(C`SUDO_PROMPT\*(C'\fR" 16
673: .IX Item "SUDO_PROMPT"
674: Used as the default password prompt
675: .ie n .IP "\*(C`SUDO_PS1\*(C'" 16
676: .el .IP "\f(CW\*(C`SUDO_PS1\*(C'\fR" 16
677: .IX Item "SUDO_PS1"
678: If set, \f(CW\*(C`PS1\*(C'\fR will be set to its value for the program being run
679: .ie n .IP "\*(C`SUDO_UID\*(C'" 16
680: .el .IP "\f(CW\*(C`SUDO_UID\*(C'\fR" 16
681: .IX Item "SUDO_UID"
682: Set to the user \s-1ID\s0 of the user who invoked sudo
683: .ie n .IP "\*(C`SUDO_USER\*(C'" 16
684: .el .IP "\f(CW\*(C`SUDO_USER\*(C'\fR" 16
685: .IX Item "SUDO_USER"
686: Set to the login of the user who invoked sudo
687: .ie n .IP "\*(C`USER\*(C'" 16
688: .el .IP "\f(CW\*(C`USER\*(C'\fR" 16
689: .IX Item "USER"
690: Set to the target user (root unless the \fB\-u\fR option is specified)
691: .ie n .IP "\*(C`VISUAL\*(C'" 16
692: .el .IP "\f(CW\*(C`VISUAL\*(C'\fR" 16
693: .IX Item "VISUAL"
694: Default editor to use in \fB\-e\fR (sudoedit) mode if \f(CW\*(C`SUDO_EDITOR\*(C'\fR
695: is not set
696: .SH "FILES"
697: .IX Header "FILES"
698: .ie n .IP "\fI@sysconfdir@/sudo.conf\fR" 24
699: .el .IP "\fI@sysconfdir@/sudo.conf\fR" 24
700: .IX Item "@sysconfdir@/sudo.conf"
701: \&\fBsudo\fR plugin and path configuration
702: .SH "EXAMPLES"
703: .IX Header "EXAMPLES"
704: Note: the following examples assume a properly configured security policy.
705: .PP
706: To get a file listing of an unreadable directory:
707: .PP
708: .Vb 1
709: \& $ sudo ls /usr/local/protected
710: .Ve
711: .PP
712: To list the home directory of user yaz on a machine where the
713: file system holding ~yaz is not exported as root:
714: .PP
715: .Vb 1
716: \& $ sudo \-u yaz ls ~yaz
717: .Ve
718: .PP
719: To edit the \fIindex.html\fR file as user www:
720: .PP
721: .Vb 1
722: \& $ sudo \-u www vi ~www/htdocs/index.html
723: .Ve
724: .PP
725: To view system logs only accessible to root and users in the adm group:
726: .PP
727: .Vb 1
728: \& $ sudo \-g adm view /var/log/syslog
729: .Ve
730: .PP
731: To run an editor as jim with a different primary group:
732: .PP
733: .Vb 1
734: \& $ sudo \-u jim \-g audio vi ~jim/sound.txt
735: .Ve
736: .PP
737: To shutdown a machine:
738: .PP
739: .Vb 1
740: \& $ sudo shutdown \-r +15 "quick reboot"
741: .Ve
742: .PP
743: To make a usage listing of the directories in the /home
744: partition. Note that this runs the commands in a sub-shell
745: to make the \f(CW\*(C`cd\*(C'\fR and file redirection work.
746: .PP
747: .Vb 1
748: \& $ sudo sh \-c "cd /home ; du \-s * | sort \-rn > USAGE"
749: .Ve
750: .SH "SEE ALSO"
751: .IX Header "SEE ALSO"
752: \&\fIgrep\fR\|(1), \fIsu\fR\|(1), \fIstat\fR\|(2),
753: .if \n(LC \&\fIlogin_cap\fR\|(3),
754: \&\fIpasswd\fR\|(@mansectform@), \fIsudoers\fR\|(@mansectform@), \fIsudo_plugin\fR\|(@mansectsu@), \fIsudoreplay\fR\|(@mansectsu@), \fIvisudo\fR\|(@mansectsu@)
755: .SH "AUTHORS"
756: .IX Header "AUTHORS"
757: Many people have worked on \fBsudo\fR over the years; this
758: version consists of code written primarily by:
759: .PP
760: .Vb 1
761: \& Todd C. Miller
762: .Ve
763: .PP
764: See the \s-1HISTORY\s0 file in the \fBsudo\fR distribution or visit
765: http://www.sudo.ws/sudo/history.html for a short history
766: of \fBsudo\fR.
767: .SH "CAVEATS"
768: .IX Header "CAVEATS"
769: There is no easy way to prevent a user from gaining a root shell
770: if that user is allowed to run arbitrary commands via \fBsudo\fR.
771: Also, many programs (such as editors) allow the user to run commands
772: via shell escapes, thus avoiding \fBsudo\fR's checks. However, on
773: most systems it is possible to prevent shell escapes with the
774: \&\fIsudoers\fR\|(@mansectform@) module's \fInoexec\fR functionality.
775: .PP
776: It is not meaningful to run the \f(CW\*(C`cd\*(C'\fR command directly via sudo, e.g.,
777: .PP
778: .Vb 1
779: \& $ sudo cd /usr/local/protected
780: .Ve
781: .PP
782: since when the command exits the parent process (your shell) will
783: still be the same. Please see the \s-1EXAMPLES\s0 section for more information.
784: .PP
785: Running shell scripts via \fBsudo\fR can expose the same kernel bugs that
786: make setuid shell scripts unsafe on some operating systems (if your \s-1OS\s0
787: has a /dev/fd/ directory, setuid shell scripts are generally safe).
788: .SH "BUGS"
789: .IX Header "BUGS"
790: If you feel you have found a bug in \fBsudo\fR, please submit a bug report
791: at http://www.sudo.ws/sudo/bugs/
792: .SH "SUPPORT"
793: .IX Header "SUPPORT"
794: Limited free support is available via the sudo-users mailing list,
795: see http://www.sudo.ws/mailman/listinfo/sudo\-users to subscribe or
796: search the archives.
797: .SH "DISCLAIMER"
798: .IX Header "DISCLAIMER"
799: \&\fBsudo\fR is provided ``\s-1AS\s0 \s-1IS\s0'' and any express or implied warranties,
800: including, but not limited to, the implied warranties of merchantability
801: and fitness for a particular purpose are disclaimed. See the \s-1LICENSE\s0
802: file distributed with \fBsudo\fR or http://www.sudo.ws/sudo/license.html
803: for complete details.
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