Annotation of src/usr.bin/sudo/sudo.8, Revision 1.1.1.1
1.1 millert 1: .rn '' }`
2: ''' $RCSfile: sudo.man,v $$Revision: 1.39 $$Date: 1999/11/16 05:42:28 $
3: '''
4: ''' $Log: sudo.man,v $
5: ''' Revision 1.39 1999/11/16 05:42:28 millert
6: ''' get rid of references to sudo-bugs. Now mention the web site or the sudo@ alias
7: '''
8: '''
9: .de Sh
10: .br
11: .if t .Sp
12: .ne 5
13: .PP
14: \fB\\$1\fR
15: .PP
16: ..
17: .de Sp
18: .if t .sp .5v
19: .if n .sp
20: ..
21: .de Ip
22: .br
23: .ie \\n(.$>=3 .ne \\$3
24: .el .ne 3
25: .IP "\\$1" \\$2
26: ..
27: .de Vb
28: .ft CW
29: .nf
30: .ne \\$1
31: ..
32: .de Ve
33: .ft R
34:
35: .fi
36: ..
37: '''
38: '''
39: ''' Set up \*(-- to give an unbreakable dash;
40: ''' string Tr holds user defined translation string.
41: ''' Bell System Logo is used as a dummy character.
42: '''
43: .tr \(*W-|\(bv\*(Tr
44: .ie n \{\
45: .ds -- \(*W-
46: .ds PI pi
47: .if (\n(.H=4u)&(1m=24u) .ds -- \(*W\h'-12u'\(*W\h'-12u'-\" diablo 10 pitch
48: .if (\n(.H=4u)&(1m=20u) .ds -- \(*W\h'-12u'\(*W\h'-8u'-\" diablo 12 pitch
49: .ds L" ""
50: .ds R" ""
51: ''' \*(M", \*(S", \*(N" and \*(T" are the equivalent of
52: ''' \*(L" and \*(R", except that they are used on ".xx" lines,
53: ''' such as .IP and .SH, which do another additional levels of
54: ''' double-quote interpretation
55: .ds M" """
56: .ds S" """
57: .ds N" """""
58: .ds T" """""
59: .ds L' '
60: .ds R' '
61: .ds M' '
62: .ds S' '
63: .ds N' '
64: .ds T' '
65: 'br\}
66: .el\{\
67: .ds -- \(em\|
68: .tr \*(Tr
69: .ds L" ``
70: .ds R" ''
71: .ds M" ``
72: .ds S" ''
73: .ds N" ``
74: .ds T" ''
75: .ds L' `
76: .ds R' '
77: .ds M' `
78: .ds S' '
79: .ds N' `
80: .ds T' '
81: .ds PI \(*p
82: 'br\}
83: .\" If the F register is turned on, we'll generate
84: .\" index entries out stderr for the following things:
85: .\" TH Title
86: .\" SH Header
87: .\" Sh Subsection
88: .\" Ip Item
89: .\" X<> Xref (embedded
90: .\" Of course, you have to process the output yourself
91: .\" in some meaninful fashion.
92: .if \nF \{
93: .de IX
94: .tm Index:\\$1\t\\n%\t"\\$2"
95: ..
96: .nr % 0
97: .rr F
98: .\}
99: .TH sudo 8 "1.6" "15/Nov/1999" "MAINTENANCE COMMANDS"
100: .UC
101: .if n .hy 0
102: .if n .na
103: .ds C+ C\v'-.1v'\h'-1p'\s-2+\h'-1p'+\s0\v'.1v'\h'-1p'
104: .de CQ \" put $1 in typewriter font
105: .ft CW
106: 'if n "\c
107: 'if t \\&\\$1\c
108: 'if n \\&\\$1\c
109: 'if n \&"
110: \\&\\$2 \\$3 \\$4 \\$5 \\$6 \\$7
111: '.ft R
112: ..
113: .\" @(#)ms.acc 1.5 88/02/08 SMI; from UCB 4.2
114: . \" AM - accent mark definitions
115: .bd B 3
116: . \" fudge factors for nroff and troff
117: .if n \{\
118: . ds #H 0
119: . ds #V .8m
120: . ds #F .3m
121: . ds #[ \f1
122: . ds #] \fP
123: .\}
124: .if t \{\
125: . ds #H ((1u-(\\\\n(.fu%2u))*.13m)
126: . ds #V .6m
127: . ds #F 0
128: . ds #[ \&
129: . ds #] \&
130: .\}
131: . \" simple accents for nroff and troff
132: .if n \{\
133: . ds ' \&
134: . ds ` \&
135: . ds ^ \&
136: . ds , \&
137: . ds ~ ~
138: . ds ? ?
139: . ds ! !
140: . ds /
141: . ds q
142: .\}
143: .if t \{\
144: . ds ' \\k:\h'-(\\n(.wu*8/10-\*(#H)'\'\h"|\\n:u"
145: . ds ` \\k:\h'-(\\n(.wu*8/10-\*(#H)'\`\h'|\\n:u'
146: . ds ^ \\k:\h'-(\\n(.wu*10/11-\*(#H)'^\h'|\\n:u'
147: . ds , \\k:\h'-(\\n(.wu*8/10)',\h'|\\n:u'
148: . ds ~ \\k:\h'-(\\n(.wu-\*(#H-.1m)'~\h'|\\n:u'
149: . ds ? \s-2c\h'-\w'c'u*7/10'\u\h'\*(#H'\zi\d\s+2\h'\w'c'u*8/10'
150: . ds ! \s-2\(or\s+2\h'-\w'\(or'u'\v'-.8m'.\v'.8m'
151: . ds / \\k:\h'-(\\n(.wu*8/10-\*(#H)'\z\(sl\h'|\\n:u'
152: . ds q o\h'-\w'o'u*8/10'\s-4\v'.4m'\z\(*i\v'-.4m'\s+4\h'\w'o'u*8/10'
153: .\}
154: . \" troff and (daisy-wheel) nroff accents
155: .ds : \\k:\h'-(\\n(.wu*8/10-\*(#H+.1m+\*(#F)'\v'-\*(#V'\z.\h'.2m+\*(#F'.\h'|\\n:u'\v'\*(#V'
156: .ds 8 \h'\*(#H'\(*b\h'-\*(#H'
157: .ds v \\k:\h'-(\\n(.wu*9/10-\*(#H)'\v'-\*(#V'\*(#[\s-4v\s0\v'\*(#V'\h'|\\n:u'\*(#]
158: .ds _ \\k:\h'-(\\n(.wu*9/10-\*(#H+(\*(#F*2/3))'\v'-.4m'\z\(hy\v'.4m'\h'|\\n:u'
159: .ds . \\k:\h'-(\\n(.wu*8/10)'\v'\*(#V*4/10'\z.\v'-\*(#V*4/10'\h'|\\n:u'
160: .ds 3 \*(#[\v'.2m'\s-2\&3\s0\v'-.2m'\*(#]
161: .ds o \\k:\h'-(\\n(.wu+\w'\(de'u-\*(#H)/2u'\v'-.3n'\*(#[\z\(de\v'.3n'\h'|\\n:u'\*(#]
162: .ds d- \h'\*(#H'\(pd\h'-\w'~'u'\v'-.25m'\f2\(hy\fP\v'.25m'\h'-\*(#H'
163: .ds D- D\\k:\h'-\w'D'u'\v'-.11m'\z\(hy\v'.11m'\h'|\\n:u'
164: .ds th \*(#[\v'.3m'\s+1I\s-1\v'-.3m'\h'-(\w'I'u*2/3)'\s-1o\s+1\*(#]
165: .ds Th \*(#[\s+2I\s-2\h'-\w'I'u*3/5'\v'-.3m'o\v'.3m'\*(#]
166: .ds ae a\h'-(\w'a'u*4/10)'e
167: .ds Ae A\h'-(\w'A'u*4/10)'E
168: .ds oe o\h'-(\w'o'u*4/10)'e
169: .ds Oe O\h'-(\w'O'u*4/10)'E
170: . \" corrections for vroff
171: .if v .ds ~ \\k:\h'-(\\n(.wu*9/10-\*(#H)'\s-2\u~\d\s+2\h'|\\n:u'
172: .if v .ds ^ \\k:\h'-(\\n(.wu*10/11-\*(#H)'\v'-.4m'^\v'.4m'\h'|\\n:u'
173: . \" for low resolution devices (crt and lpr)
174: .if \n(.H>23 .if \n(.V>19 \
175: \{\
176: . ds : e
177: . ds 8 ss
178: . ds v \h'-1'\o'\(aa\(ga'
179: . ds _ \h'-1'^
180: . ds . \h'-1'.
181: . ds 3 3
182: . ds o a
183: . ds d- d\h'-1'\(ga
184: . ds D- D\h'-1'\(hy
185: . ds th \o'bp'
186: . ds Th \o'LP'
187: . ds ae ae
188: . ds Ae AE
189: . ds oe oe
190: . ds Oe OE
191: .\}
192: .rm #[ #] #H #V #F C
193: .SH "NAME"
194: sudo \- execute a command as another user
195: .SH "SYNOPSIS"
196: \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 | \fB\-H\fR |
197: [ \fB\-b\fR ] | [ \fB\-p\fR prompt ] [ \fB\-u\fR username/#uid] \fIcommand\fR
198: .SH "DESCRIPTION"
199: \fBsudo\fR allows a permitted user to execute a \fIcommand\fR as the
200: superuser or another user, as specified in the sudoers file. The
201: real and effective uid and gid are set to match those of the target
202: user as specified in the passwd file (the group vector is also
203: initialized when the target user is not root).
204: .PP
205: \fBsudo\fR determines who is an authorized user by consulting the
206: file \fI/etc/sudoers\fR. By giving \fBsudo\fR the \f(CW-v\fR flag a user
207: can update the time stamp without running a \fIcommand.\fR
208: The password prompt itself will also time out if the user's password is
209: not entered with N minutes (again, this is defined at configure
210: time and defaults to 5 minutes).
211: .PP
212: If a user that is not listed in the \fIsudoers\fR file tries to run
213: a command via \fBsudo\fR, mail is sent to the proper authorities,
214: as defined at configure time (defaults to root). Note that the
215: mail will not be sent if an unauthorized user tries to run sudo
216: with the \f(CW-l\fR or \f(CW-v\fR flags. This allows users to determine
217: for themselves whether or not they are allowed to use \fBsudo\fR.
218: .PP
219: \fBsudo\fR can log both successful an unsuccessful attempts (as well
220: as errors) to \fIsyslog\fR\|(3), a log file, or both. By default \fBsudo\fR
221: will log via \fIsyslog\fR\|(3) but this is changeable at configure time.
222: .SH "OPTIONS"
223: \fBsudo\fR accepts the following command line options:
224: .Ip "-V" 4
225: The \f(CW-V\fR (\fIversion\fR) option causes \fBsudo\fR to print the
226: version number and exit.
227: .Ip "-l" 4
228: The \f(CW-l\fR (\fIlist\fR) option will list out the allowed (and
229: forbidden) commands for the user on the current host.
230: .Ip "-L" 4
231: The \f(CW-L\fR (\fIlist\fR defaults) option will list out the parameters
232: that may be set in a \fIDefaults\fR line along with a short description
233: for each. This option is useful in conjunction with \fIgrep\fR\|(1).
234: .Ip "-h" 4
235: The \f(CW-h\fR (\fIhelp\fR) option causes \fBsudo\fR to print a usage message and exit.
236: .Ip "-v" 4
237: If given the \f(CW-v\fR (\fIvalidate\fR) option, \fBsudo\fR will update the
238: user's timestamp, prompting for the user's password if necessary.
239: This extends the \fBsudo\fR timeout to for another N minutes
240: (where N is defined at installation time and defaults to 5
241: minutes) but does not run a command.
242: .Ip "-k" 4
243: The \f(CW-k\fR (\fIkill\fR) option to \fBsudo\fR invalidates the user's timestamp
244: by setting the time on it to the epoch. The next time \fBsudo\fR is
245: run a password will be required. This option does not require a password
246: and was added to allow a user to revoke \fBsudo\fR permissions from a .logout
247: file.
248: .Ip "-K" 4
249: The \f(CW-K\fR (sure \fIkill\fR) option to \fBsudo\fR removes the user's timestamp
250: entirely. This option does not require a password.
251: .Ip "-b" 4
252: The \f(CW-b\fR (\fIbackground\fR) option tells \fBsudo\fR to run the given
253: command in the background. Note that if you use the \f(CW-b\fR
254: option you cannot use shell job control to manipulate the command.
255: .Ip "-p" 4
256: The \f(CW-p\fR (\fIprompt\fR) option allows you to override the default
257: password prompt and use a custom one. If the password prompt
258: contains the \f(CW%u\fR escape, \f(CW%u\fR will be replaced with the user's
259: login name. Similarly, \f(CW%h\fR will be replaced with the local
260: hostname.
261: .Ip "-u" 4
262: The \f(CW-u\fR (\fIuser\fR) option causes sudo to run the specified command
263: as a user other than \fIroot\fR. To specify a \fIuid\fR instead of a
264: \fIusername\fR, use \*(L"#uid\*(R".
265: .Ip "-s" 4
266: The \f(CW-s\fR (\fIshell\fR) option runs the shell specified by the \fI\s-1SHELL\s0\fR
267: environment variable if it is set or the shell as specified
268: in \fIpasswd\fR\|(5).
269: .Ip "-H" 4
270: The \f(CW-H\fR (\fI\s-1HOME\s0\fR) option sets the \fI\s-1HOME\s0\fR environment variable
271: to the homedir of the target user (root by default) as specified
272: in \fIpasswd\fR\|(5). By default, \fBsudo\fR does not modify \fI\s-1HOME\s0\fR.
273: .Ip "--" 4
274: The \f(CW--\fR flag indicates that \fBsudo\fR should stop processing command
275: line arguments. It is most useful in conjunction with the \f(CW-s\fR flag.
276: .SH "RETURN VALUES"
277: \fBsudo\fR quits with an exit value of 1 if there is a
278: configuration/permission problem or if \fBsudo\fR cannot execute the
279: given command. In the latter case the error string is printed to
280: stderr. If \fBsudo\fR cannot \fIstat\fR\|(2) one or more entries in the user's
281: \f(CWPATH\fR an error is printed on stderr. (If the directory does not
282: exist or if it is not really a directory, the entry is ignored and
283: no error is printed.) This should not happen under normal
284: circumstances. The most common reason for \fIstat\fR\|(2) to return
285: \*(L"permission denied\*(R" is if you are running an automounter and one
286: of the directories in your \f(CWPATH\fR is on a machine that is currently
287: unreachable.
288: .SH "SECURITY NOTES"
289: \fBsudo\fR tries to be safe when executing external commands. Variables
290: that control how dynamic loading and binding is done can be used
291: to subvert the program that \fBsudo\fR runs. To combat this the
292: \f(CWLD_*\fR, \f(CW_RLD_*\fR, \f(CWSHLIB_PATH\fR (HP\-UX only), and \f(CWLIBPATH\fR (AIX
293: only) environment variables are removed from the environment passed
294: on to all commands executed. \fBsudo\fR will also remove the \f(CWIFS\fR,
295: \f(CWENV\fR, \f(CWBASH_ENV\fR, \f(CWKRB_CONF\fR, \f(CWKRB5_CONFIG\fR, \f(CWLOCALDOMAIN\fR,
296: \f(CWRES_OPTIONS\fR and \f(CWHOSTALIASES\fR variables as they too can pose a
297: threat.
298: .PP
299: To prevent command spoofing, \fBsudo\fR checks "." and "" (both denoting
300: current directory) last when searching for a command in the user's
301: PATH (if one or both are in the PATH). Note, however, that the
302: actual \f(CWPATH\fR environment variable is \fInot\fR modified and is passed
303: unchanged to the program that \fBsudo\fR executes.
304: .PP
305: For security reasons, if your OS supports shared libraries and does
306: not disable user-defined library search paths for setuid programs
307: (most do), you should either use a linker option that disables this
308: behavior or link \fBsudo\fR statically.
309: .PP
310: \fBsudo\fR will check the ownership of its timestamp directory
311: (\fI/var/run/sudo\fR or \fI/tmp/.odus\fR by default) and ignore the
312: directory's contents if it is not owned by root and only writable
313: by root. On systems that allow non-root users to give away files
314: via \fIchown\fR\|(2), if the timestamp directory is located in a directory
315: writable by anyone (ie: \fI/tmp\fR), it is possible for a user to
316: create the timestamp directory before \fBsudo\fR is run. However,
317: because \fBsudo\fR checks the ownership and mode of the directory and
318: its contents, the only damage that can be done is to \*(L"hide\*(R" files
319: by putting them in the timestamp dir. This is unlikely to happen
320: since once the timestamp dir is owned by root and inaccessible by
321: any other user the user placing files there would be unable to get
322: them back out. To get around this issue you can use a directory
323: that is not world-writable for the timestamps (\fI/var/adm/sudo\fR for
324: instance) or create /tmp/.odus with the appropriate owner (root)
325: and permissions (0700) in the system startup files.
326: .PP
327: \fBsudo\fR will not honor timestamps set far in the future.
328: Timestamps with a date greater than current_time + 2 * \f(CWTIMEOUT\fR
329: will be ignored and sudo will log and complain. This is done to
330: keep a user from creating his/her own timestamp with a bogus
331: date on system that allow users to give away files.
332: .SH "EXAMPLES"
333: Note: the following examples assume suitable \fIsudoers\fR\|(5) entries.
334: .PP
335: To get a file listing of an unreadable directory:
336: .PP
337: .Vb 1
338: \& % sudo ls /usr/local/protected
339: .Ve
340: To list the home directory of user yazza on a machine where the
341: filesystem holding ~yazza is not exported as root:
342: .PP
343: .Vb 1
344: \& % sudo -u yazza ls ~yazza
345: .Ve
346: To edit the \fIindex.html\fR file as user www:
347: .PP
348: .Vb 1
349: \& % sudo -u www vi ~www/htdocs/index.html
350: .Ve
351: To shutdown a machine:
352: .PP
353: .Vb 1
354: \& % sudo shutdown -r +15 "quick reboot"
355: .Ve
356: To make a usage listing of the directories in the /home
357: partition. Note that this runs the commands in a sub-shell
358: to make the \f(CWcd\fR and file redirection work.
359: .PP
360: .Vb 1
361: \& % sudo sh -c "cd /home ; du -s * | sort -rn > USAGE"
362: .Ve
363: .SH "ENVIRONMENT"
364: \fBsudo\fR utilizes the following environment variables:
365: .PP
366: .Vb 13
367: \& PATH Set to a sane value if SECURE_PATH is set
368: \& SHELL Used to determine shell to run with -s option
369: \& USER Set to the target user (root unless the -u option
370: \& is specified)
371: \& HOME In -s or -H mode (or if sudo was configured with
372: \& the --enable-shell-sets-home option), set to
373: \& homedir of the target user.
374: \& SUDO_PROMPT Used as the default password prompt
375: \& SUDO_COMMAND Set to the command run by sudo
376: \& SUDO_USER Set to the login of the user who invoked sudo
377: \& SUDO_UID Set to the uid of the user who invoked sudo
378: \& SUDO_GID Set to the gid of the user who invoked sudo
379: \& SUDO_PS1 If set, PS1 will be set to its value
380: .Ve
381: .SH "FILES"
382: .PP
383: .Vb 2
384: \& /etc/sudoers List of who can run what
385: \& /var/run/sudo Directory containing timestamps
386: .Ve
387: \fBsudo\fR utilizes the following environment variables:
388: .PP
389: .Vb 13
390: \& PATH Set to a sane value if SECURE_PATH is set
391: \& SHELL Used to determine shell to run with -s option
392: \& USER Set to the target user (root unless the -u option
393: \& is specified)
394: \& HOME In -s or -H mode (or if sudo was configured with
395: \& the --enable-shell-sets-home option), set to
396: \& homedir of the target user.
397: \& SUDO_PROMPT Used as the default password prompt
398: \& SUDO_COMMAND Set to the command run by sudo
399: \& SUDO_USER Set to the login of the user who invoked sudo
400: \& SUDO_UID Set to the uid of the user who invoked sudo
401: \& SUDO_GID Set to the gid of the user who invoked sudo
402: \& SUDO_PS1 If set, PS1 will be set to its value
403: .Ve
404: .SH "FILES"
405: .PP
406: .Vb 3
407: \& /etc/sudoers List of who can run what
408: \& /var/run/sudo Directory containing timestamps
409: \& /tmp/.odus Same as above if no /var/run exists
410: .Ve
411: .SH "AUTHORS"
412: Many people have worked on \fBsudo\fR over the years, this
413: version consists of code written primarily by:
414: .PP
415: .Vb 2
416: \& Todd Miller
417: \& Chris Jepeway
418: .Ve
419: See the HISTORY file in the \fBsudo\fR distribution for a short history
420: of \fBsudo\fR.
421: .SH "BUGS"
422: If you feel you have found a bug in sudo, please submit a bug report
423: at http://www.courtesan.com/sudo/bugs/.
424: .SH "DISCLAIMER"
425: \fBSudo\fR is provided ``AS IS'\*(R' and any express or implied warranties,
426: including, but not limited to, the implied warranties of merchantability
427: and fitness for a particular purpose are disclaimed.
428: See the LICENSE file distributed with \fBsudo\fR for complete details.
429: .SH "CAVEATS"
430: There is no easy way to prevent a user from gaining a root shell if
431: that user has access to commands allowing shell escapes.
432: .PP
433: If users have sudo \f(CWALL\fR there is nothing to prevent them from creating
434: their own program that gives them a root shell regardless of any \*(L'!\*(R'
435: elements in the user specification.
436: .PP
437: Running shell scripts via \fBsudo\fR can expose the same kernel bugs
438: that make setuid shell scripts unsafe on some operating systems
439: (if your OS supports the /dev/fd/ directory, setuid shell scripts
440: are generally safe).
441: .SH "SEE ALSO"
442: \fIsudoers\fR\|(5), \fIvisudo\fR\|(8), \fIsu\fR\|(1).
443:
444: .rn }` ''
445: .IX Title "sudo 8"
446: .IX Name "sudo - execute a command as another user"
447:
448: .IX Header "NAME"
449:
450: .IX Header "SYNOPSIS"
451:
452: .IX Header "DESCRIPTION"
453:
454: .IX Header "OPTIONS"
455:
456: .IX Item "-V"
457:
458: .IX Item "-l"
459:
460: .IX Item "-L"
461:
462: .IX Item "-h"
463:
464: .IX Item "-v"
465:
466: .IX Item "-k"
467:
468: .IX Item "-K"
469:
470: .IX Item "-b"
471:
472: .IX Item "-p"
473:
474: .IX Item "-u"
475:
476: .IX Item "-s"
477:
478: .IX Item "-H"
479:
480: .IX Item "--"
481:
482: .IX Header "RETURN VALUES"
483:
484: .IX Header "SECURITY NOTES"
485:
486: .IX Header "EXAMPLES"
487:
488: .IX Header "ENVIRONMENT"
489:
490: .IX Header "FILES"
491:
492: .IX Header "FILES"
493:
494: .IX Header "AUTHORS"
495:
496: .IX Header "BUGS"
497:
498: .IX Header "DISCLAIMER"
499:
500: .IX Header "CAVEATS"
501:
502: .IX Header "SEE ALSO"
503:
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