1 .\" Automatically generated by Pod::Man version 1.15
2 .\" Thu Apr 25 09:34:52 2002
5 .\" ======================================================================
6 .de Sh \" Subsection heading
14 .de Sp \" Vertical space (when we can't use .PP)
20 .ie \\n(.$>=3 .ne \\$3
24 .de Vb \" Begin verbatim text
29 .de Ve \" End verbatim text
34 .\" Set up some character translations and predefined strings. \*(-- will
35 .\" give an unbreakable dash, \*(PI will give pi, \*(L" will give a left
36 .\" double quote, and \*(R" will give a right double quote. | will give a
37 .\" real vertical bar. \*(C+ will give a nicer C++. Capital omega is used
38 .\" to do unbreakable dashes and therefore won't be available. \*(C` and
39 .\" \*(C' expand to `' in nroff, nothing in troff, for use with C<>
41 .ds C+ C\v'-.1v'\h'-1p'\s-2+\h'-1p'+\s0\v'.1v'\h'-1p'
45 . if (\n(.H=4u)&(1m=24u) .ds -- \(*W\h'-12u'\(*W\h'-12u'-\" diablo 10 pitch
46 . if (\n(.H=4u)&(1m=20u) .ds -- \(*W\h'-12u'\(*W\h'-8u'-\" diablo 12 pitch
59 .\" If the F register is turned on, we'll generate index entries on stderr
60 .\" for titles (.TH), headers (.SH), subsections (.Sh), items (.Ip), and
61 .\" index entries marked with X<> in POD. Of course, you'll have to process
62 .\" the output yourself in some meaningful fashion.
65 . tm Index:\\$1\t\\n%\t"\\$2"
71 .\" For nroff, turn off justification. Always turn off hyphenation; it
72 .\" makes way too many mistakes in technical documents.
76 .\" Accent mark definitions (@(#)ms.acc 1.5 88/02/08 SMI; from UCB 4.2).
77 .\" Fear. Run. Save yourself. No user-serviceable parts.
79 . \" fudge factors for nroff and troff
88 . ds #H ((1u-(\\\\n(.fu%2u))*.13m)
94 . \" simple accents for nroff and troff
104 . ds ' \\k:\h'-(\\n(.wu*8/10-\*(#H)'\'\h"|\\n:u"
105 . ds ` \\k:\h'-(\\n(.wu*8/10-\*(#H)'\`\h'|\\n:u'
106 . ds ^ \\k:\h'-(\\n(.wu*10/11-\*(#H)'^\h'|\\n:u'
107 . ds , \\k:\h'-(\\n(.wu*8/10)',\h'|\\n:u'
108 . ds ~ \\k:\h'-(\\n(.wu-\*(#H-.1m)'~\h'|\\n:u'
109 . ds / \\k:\h'-(\\n(.wu*8/10-\*(#H)'\z\(sl\h'|\\n:u'
111 . \" troff and (daisy-wheel) nroff accents
112 .ds : \\k:\h'-(\\n(.wu*8/10-\*(#H+.1m+\*(#F)'\v'-\*(#V'\z.\h'.2m+\*(#F'.\h'|\\n:u'\v'\*(#V'
113 .ds 8 \h'\*(#H'\(*b\h'-\*(#H'
114 .ds o \\k:\h'-(\\n(.wu+\w'\(de'u-\*(#H)/2u'\v'-.3n'\*(#[\z\(de\v'.3n'\h'|\\n:u'\*(#]
115 .ds d- \h'\*(#H'\(pd\h'-\w'~'u'\v'-.25m'\f2\(hy\fP\v'.25m'\h'-\*(#H'
116 .ds D- D\\k:\h'-\w'D'u'\v'-.11m'\z\(hy\v'.11m'\h'|\\n:u'
117 .ds th \*(#[\v'.3m'\s+1I\s-1\v'-.3m'\h'-(\w'I'u*2/3)'\s-1o\s+1\*(#]
118 .ds Th \*(#[\s+2I\s-2\h'-\w'I'u*3/5'\v'-.3m'o\v'.3m'\*(#]
119 .ds ae a\h'-(\w'a'u*4/10)'e
120 .ds Ae A\h'-(\w'A'u*4/10)'E
121 . \" corrections for vroff
122 .if v .ds ~ \\k:\h'-(\\n(.wu*9/10-\*(#H)'\s-2\u~\d\s+2\h'|\\n:u'
123 .if v .ds ^ \\k:\h'-(\\n(.wu*10/11-\*(#H)'\v'-.4m'^\v'.4m'\h'|\\n:u'
124 . \" for low resolution devices (crt and lpr)
125 .if \n(.H>23 .if \n(.V>19 \
138 .\" ======================================================================
140 .IX Title "sudo @mansectsu@"
141 .TH sudo @mansectsu@ "1.6.6" "April 25, 2002" "MAINTENANCE COMMANDS"
144 sudo \- execute a command as another user
146 .IX Header "SYNOPSIS"
147 \&\fBsudo\fR \fB\-V\fR | \fB\-h\fR | \fB\-l\fR | \fB\-L\fR | \fB\-v\fR | \fB\-k\fR | \fB\-K\fR | \fB\-s\fR |
148 [ \fB\-H\fR ] [\fB\-P\fR ] [\fB\-S\fR ] [ \fB\-b\fR ] | [ \fB\-p\fR \fIprompt\fR ]
149 [ \fB\-c\fR \fIclass\fR|\fI-\fR ] [ \fB\-a\fR \fIauth_type\fR ]
150 [ \fB\-u\fR \fIusername\fR|\fI#uid\fR ] \fIcommand\fR
152 .IX Header "DESCRIPTION"
153 \&\fBsudo\fR allows a permitted user to execute a \fIcommand\fR as the
154 superuser or another user, as specified in the \fIsudoers\fR file.
155 The real and effective uid and gid are set to match those of the
156 target user as specified in the passwd file (the group vector is
157 also initialized when the target user is not root). By default,
158 \&\fBsudo\fR requires that users authenticate themselves with a password
159 (\s-1NOTE:\s0 by default this is the user's password, not the root password).
160 Once a user has been authenticated, a timestamp is updated and the
161 user may then use sudo without a password for a short period of
162 time (\f(CW\*(C`@timeout@\*(C'\fR minutes unless overridden in \fIsudoers\fR).
164 \&\fBsudo\fR determines who is an authorized user by consulting the file
165 \&\fI@sysconfdir@/sudoers\fR. By giving \fBsudo\fR the \fB\-v\fR flag a user
166 can update the time stamp without running a \fIcommand.\fR The password
167 prompt itself will also time out if the user's password is not
168 entered within \f(CW\*(C`@password_timeout@\*(C'\fR minutes (unless overridden via
171 If a user who is not listed in the \fIsudoers\fR file tries to run a
172 command via \fBsudo\fR, mail is sent to the proper authorities, as
173 defined at configure time or the \fIsudoers\fR file (defaults to root).
174 Note that the mail will not be sent if an unauthorized user tries
175 to run sudo with the \fB\-l\fR or \fB\-v\fR flags. This allows users to
176 determine for themselves whether or not they are allowed to use
179 \&\fBsudo\fR can log both successful and unsuccessful attempts (as well
180 as errors) to \fIsyslog\fR\|(3), a log file, or both. By default \fBsudo\fR
181 will log via \fIsyslog\fR\|(3) but this is changeable at configure time
182 or via the \fIsudoers\fR file.
185 \&\fBsudo\fR accepts the following command line options:
188 The \fB\-V\fR (\fIversion\fR) option causes \fBsudo\fR to print the
189 version number and exit. If the invoking user is already root
190 the \fB\-V\fR option will print out a list of the defaults \fBsudo\fR
191 was compiled with as well as the machine's local network addresses.
194 The \fB\-l\fR (\fIlist\fR) option will list out the allowed (and
195 forbidden) commands for the user on the current host.
198 The \fB\-L\fR (\fIlist\fR defaults) option will list out the parameters
199 that may be set in a \fIDefaults\fR line along with a short description
200 for each. This option is useful in conjunction with \fIgrep\fR\|(1).
203 The \fB\-h\fR (\fIhelp\fR) option causes \fBsudo\fR to print a usage message and exit.
206 If given the \fB\-v\fR (\fIvalidate\fR) option, \fBsudo\fR will update the
207 user's timestamp, prompting for the user's password if necessary.
208 This extends the \fBsudo\fR timeout for another \f(CW\*(C`@timeout@\*(C'\fR minutes
209 (or whatever the timeout is set to in \fIsudoers\fR) but does not run
213 The \fB\-k\fR (\fIkill\fR) option to \fBsudo\fR invalidates the user's timestamp
214 by setting the time on it to the epoch. The next time \fBsudo\fR is
215 run a password will be required. This option does not require a password
216 and was added to allow a user to revoke \fBsudo\fR permissions from a .logout
220 The \fB\-K\fR (sure \fIkill\fR) option to \fBsudo\fR removes the user's timestamp
221 entirely. Likewise, this option does not require a password.
224 The \fB\-b\fR (\fIbackground\fR) option tells \fBsudo\fR to run the given
225 command in the background. Note that if you use the \fB\-b\fR
226 option you cannot use shell job control to manipulate the process.
229 The \fB\-p\fR (\fIprompt\fR) option allows you to override the default
230 password prompt and use a custom one. If the password prompt
231 contains the \f(CW\*(C`%u\*(C'\fR escape, \f(CW\*(C`%u\*(C'\fR will be replaced with the user's
232 login name. Similarly, \f(CW\*(C`%h\*(C'\fR will be replaced with the local
236 The \fB\-c\fR (\fIclass\fR) option causes \fBsudo\fR to run the specified command
237 with resources limited by the specified login class. The \fIclass\fR
238 argument can be either a class name as defined in /etc/login.conf,
239 or a single '\-' character. Specifying a \fIclass\fR of \f(CW\*(C`\-\*(C'\fR indicates
240 that the command should be run restricted by the default login
241 capabilities for the user the command is run as. If the \fIclass\fR
242 argument specifies an existing user class, the command must be run
243 as root, or the \fBsudo\fR command must be run from a shell that is already
244 root. This option is only available on systems with \s-1BSD\s0 login classes
245 where \fBsudo\fR has been configured with the \-\-with-logincap option.
248 The \fB\-a\fR (\fIauthentication type\fR) option causes \fBsudo\fR to use the
249 specified authentication type when validating the user, as allowed
250 by /etc/login.conf. The system administrator may specify a list
251 of sudo-specific authentication methods by adding an \*(L"auth-sudo\*(R"
252 entry in /etc/login.conf. This option is only available on systems
253 that support \s-1BSD\s0 authentication where \fBsudo\fR has been configured
254 with the \-\-with-bsdauth option.
257 The \fB\-u\fR (\fIuser\fR) option causes \fBsudo\fR to run the specified command
258 as a user other than \fIroot\fR. To specify a \fIuid\fR instead of a
259 \&\fIusername\fR, use \fI#uid\fR.
262 The \fB\-s\fR (\fIshell\fR) option runs the shell specified by the \fI\s-1SHELL\s0\fR
263 environment variable if it is set or the shell as specified
264 in \fIpasswd\fR\|(@mansectform@).
267 The \fB\-H\fR (\fI\s-1HOME\s0\fR) option sets the \f(CW\*(C`HOME\*(C'\fR environment variable
268 to the homedir of the target user (root by default) as specified
269 in \fIpasswd\fR\|(@mansectform@). By default, \fBsudo\fR does not modify \f(CW\*(C`HOME\*(C'\fR.
272 The \fB\-P\fR (\fIpreserve group vector\fR) option causes \fBsudo\fR to preserve
273 the user's group vector unaltered. By default, \fBsudo\fR will initialize
274 the group vector to the list of groups the target user is in.
275 The real and effective group IDs, however, are still set to match
279 The \fB\-S\fR (\fIstdin\fR) option causes \fBsudo\fR to read the password from
280 standard input instead of the terminal device.
282 The \fB\--\fR flag indicates that \fBsudo\fR should stop processing command
283 line arguments. It is most useful in conjunction with the \fB\-s\fR flag.
285 .IX Header "RETURN VALUES"
286 Upon successful execution of a program, the return value from \fBsudo\fR
287 will simply be the return value of the program that was executed.
289 Otherwise, \fBsudo\fR quits with an exit value of 1 if there is a
290 configuration/permission problem or if \fBsudo\fR cannot execute the
291 given command. In the latter case the error string is printed to
292 stderr. If \fBsudo\fR cannot \fIstat\fR\|(2) one or more entries in the user's
293 \&\f(CW\*(C`PATH\*(C'\fR an error is printed on stderr. (If the directory does not
294 exist or if it is not really a directory, the entry is ignored and
295 no error is printed.) This should not happen under normal
296 circumstances. The most common reason for \fIstat\fR\|(2) to return
297 \&\*(L"permission denied\*(R" is if you are running an automounter and one
298 of the directories in your \f(CW\*(C`PATH\*(C'\fR is on a machine that is currently
301 .IX Header "SECURITY NOTES"
302 \&\fBsudo\fR tries to be safe when executing external commands. Variables
303 that control how dynamic loading and binding is done can be used
304 to subvert the program that \fBsudo\fR runs. To combat this the
305 \&\f(CW\*(C`LD_*\*(C'\fR, \f(CW\*(C`_RLD_*\*(C'\fR, \f(CW\*(C`SHLIB_PATH\*(C'\fR (\s-1HP-UX\s0 only), and \f(CW\*(C`LIBPATH\*(C'\fR (\s-1AIX\s0
306 only) environment variables are removed from the environment passed
307 on to all commands executed. \fBsudo\fR will also remove the \f(CW\*(C`IFS\*(C'\fR,
308 \&\f(CW\*(C`ENV\*(C'\fR, \f(CW\*(C`BASH_ENV\*(C'\fR, \f(CW\*(C`KRB_CONF\*(C'\fR, \f(CW\*(C`KRBCONFDIR\*(C'\fR, \f(CW\*(C`KRBTKFILE\*(C'\fR,
309 \&\f(CW\*(C`KRB5_CONFIG\*(C'\fR, \f(CW\*(C`LOCALDOMAIN\*(C'\fR, \f(CW\*(C`RES_OPTIONS\*(C'\fR, \f(CW\*(C`HOSTALIASES\*(C'\fR,
310 \&\f(CW\*(C`NLSPATH\*(C'\fR, \f(CW\*(C`PATH_LOCALE\*(C'\fR, \f(CW\*(C`TERMINFO\*(C'\fR, \f(CW\*(C`TERMINFO_DIRS\*(C'\fR and
311 \&\f(CW\*(C`TERMPATH\*(C'\fR variables as they too can pose a threat. If the
312 \&\f(CW\*(C`TERMCAP\*(C'\fR variable is set and is a pathname, it too is ignored.
313 Additionally, if the \f(CW\*(C`LC_*\*(C'\fR or \f(CW\*(C`LANGUAGE\*(C'\fR variables contain the
314 \&\f(CW\*(C`/\*(C'\fR or \f(CW\*(C`%\*(C'\fR characters, they are ignored. If \fBsudo\fR has been
315 compiled with SecurID support, the \f(CW\*(C`VAR_ACE\*(C'\fR, \f(CW\*(C`USR_ACE\*(C'\fR and
316 \&\f(CW\*(C`DLC_ACE\*(C'\fR variables are cleared as well. The list of environment
317 variables that \fBsudo\fR clears is contained in the output of
318 \&\f(CW\*(C`sudo \-V\*(C'\fR when run as root.
320 To prevent command spoofing, \fBsudo\fR checks \*(L".\*(R" and "" (both denoting
321 current directory) last when searching for a command in the user's
322 \&\s-1PATH\s0 (if one or both are in the \s-1PATH\s0). Note, however, that the
323 actual \f(CW\*(C`PATH\*(C'\fR environment variable is \fInot\fR modified and is passed
324 unchanged to the program that \fBsudo\fR executes.
326 For security reasons, if your \s-1OS\s0 supports shared libraries and does
327 not disable user-defined library search paths for setuid programs
328 (most do), you should either use a linker option that disables this
329 behavior or link \fBsudo\fR statically.
331 \&\fBsudo\fR will check the ownership of its timestamp directory
332 (\fI@timedir@\fR by default) and ignore the directory's contents if
333 it is not owned by root and only writable by root. On systems that
334 allow non-root users to give away files via \fIchown\fR\|(2), if the timestamp
335 directory is located in a directory writable by anyone (e.g.: \fI/tmp\fR),
336 it is possible for a user to create the timestamp directory before
337 \&\fBsudo\fR is run. However, because \fBsudo\fR checks the ownership and
338 mode of the directory and its contents, the only damage that can
339 be done is to \*(L"hide\*(R" files by putting them in the timestamp dir.
340 This is unlikely to happen since once the timestamp dir is owned
341 by root and inaccessible by any other user the user placing files
342 there would be unable to get them back out. To get around this
343 issue you can use a directory that is not world-writable for the
344 timestamps (\fI/var/adm/sudo\fR for instance) or create \fI@timedir@\fR
345 with the appropriate owner (root) and permissions (0700) in the
346 system startup files.
348 \&\fBsudo\fR will not honor timestamps set far in the future.
349 Timestamps with a date greater than current_time + 2 * \f(CW\*(C`TIMEOUT\*(C'\fR
350 will be ignored and sudo will log and complain. This is done to
351 keep a user from creating his/her own timestamp with a bogus
352 date on systems that allow users to give away files.
354 Please note that \fBsudo\fR will only log the command it explicitly
355 runs. If a user runs a command such as \f(CW\*(C`sudo su\*(C'\fR or \f(CW\*(C`sudo sh\*(C'\fR,
356 subsequent commands run from that shell will \fInot\fR be logged, nor
357 will \fBsudo\fR's access control affect them. The same is true for
358 commands that offer shell escapes (including most editors). Because
359 of this, care must be taken when giving users access to commands
360 via \fBsudo\fR to verify that the command does not inadvertantly give
361 the user an effective root shell.
363 .IX Header "EXAMPLES"
364 Note: the following examples assume suitable \fIsudoers\fR\|(@mansectform@) entries.
366 To get a file listing of an unreadable directory:
369 \& % sudo ls /usr/local/protected
371 To list the home directory of user yazza on a machine where the
372 filesystem holding ~yazza is not exported as root:
375 \& % sudo -u yazza ls ~yazza
377 To edit the \fIindex.html\fR file as user www:
380 \& % sudo -u www vi ~www/htdocs/index.html
382 To shutdown a machine:
385 \& % sudo shutdown -r +15 "quick reboot"
387 To make a usage listing of the directories in the /home
388 partition. Note that this runs the commands in a sub-shell
389 to make the \f(CW\*(C`cd\*(C'\fR and file redirection work.
392 \& % sudo sh -c "cd /home ; du -s * | sort -rn > USAGE"
395 .IX Header "ENVIRONMENT"
396 \&\fBsudo\fR utilizes the following environment variables:
399 \& PATH Set to a sane value if SECURE_PATH is set
400 \& SHELL Used to determine shell to run with -s option
401 \& USER Set to the target user (root unless the -u option
403 \& HOME In -s or -H mode (or if sudo was configured with
404 \& the --enable-shell-sets-home option), set to
405 \& homedir of the target user.
406 \& SUDO_PROMPT Used as the default password prompt
407 \& SUDO_COMMAND Set to the command run by sudo
408 \& SUDO_USER Set to the login of the user who invoked sudo
409 \& SUDO_UID Set to the uid of the user who invoked sudo
410 \& SUDO_GID Set to the gid of the user who invoked sudo
411 \& SUDO_PS1 If set, PS1 will be set to its value
416 \& @sysconfdir@/sudoers List of who can run what
417 \& @timedir@ Directory containing timestamps
421 Many people have worked on \fBsudo\fR over the years; this
422 version consists of code written primarily by:
428 See the \s-1HISTORY\s0 file in the \fBsudo\fR distribution or visit
429 http://www.sudo.ws/sudo/history.html for a short history
433 If you feel you have found a bug in sudo, please submit a bug report
434 at http://www.sudo.ws/sudo/bugs/
436 .IX Header "DISCLAIMER"
437 \&\fBSudo\fR is provided ``\s-1AS\s0 \s-1IS\s0'' and any express or implied warranties,
438 including, but not limited to, the implied warranties of merchantability
439 and fitness for a particular purpose are disclaimed.
440 See the \s-1LICENSE\s0 file distributed with \fBsudo\fR for complete details.
443 There is no easy way to prevent a user from gaining a root shell if
444 that user has access to commands allowing shell escapes.
446 If users have sudo \f(CW\*(C`ALL\*(C'\fR there is nothing to prevent them from creating
447 their own program that gives them a root shell regardless of any '!'
448 elements in the user specification.
450 Running shell scripts via \fBsudo\fR can expose the same kernel bugs
451 that make setuid shell scripts unsafe on some operating systems
452 (if your \s-1OS\s0 supports the /dev/fd/ directory, setuid shell scripts
455 .IX Header "SEE ALSO"
456 \&\fIstat\fR\|(2), \fIlogin_cap\fR\|(3), \fIsudoers\fR\|(@mansectform@), \fIpasswd\fR\|(5), \fIvisudo\fR\|(@mansectsu@), \fIgrep\fR\|(1), \fIsu\fR\|(1).
projects / debian / sudo / blob