.rn '' }` ''' $RCSfile$$Revision$$Date$ ''' ''' $Log$ ''' Revision 1.26 1999/01/17 21:31:37 millert ''' regen based on sudo.pod, sudoers.pod, and visudo.pod ''' ''' .de Sh .br .if t .Sp .ne 5 .PP \fB\\$1\fR .PP .. .de Sp .if t .sp .5v .if n .sp .. .de Ip .br .ie \\n(.$>=3 .ne \\$3 .el .ne 3 .IP "\\$1" \\$2 .. .de Vb .ft CW .nf .ne \\$1 .. .de Ve .ft R .fi .. ''' ''' ''' Set up \*(-- to give an unbreakable dash; ''' string Tr holds user defined translation string. ''' Bell System Logo is used as a dummy character. ''' .tr \(*W-|\(bv\*(Tr .ie n \{\ .ds -- \(*W- .ds PI pi .if (\n(.H=4u)&(1m=24u) .ds -- \(*W\h'-12u'\(*W\h'-12u'-\" diablo 10 pitch .if (\n(.H=4u)&(1m=20u) .ds -- \(*W\h'-12u'\(*W\h'-8u'-\" diablo 12 pitch .ds L" "" .ds R" "" ''' \*(M", \*(S", \*(N" and \*(T" are the equivalent of ''' \*(L" and \*(R", except that they are used on ".xx" lines, ''' such as .IP and .SH, which do another additional levels of ''' double-quote interpretation .ds M" """ .ds S" """ .ds N" """"" .ds T" """"" .ds L' ' .ds R' ' .ds M' ' .ds S' ' .ds N' ' .ds T' ' 'br\} .el\{\ .ds -- \(em\| .tr \*(Tr .ds L" `` .ds R" '' .ds M" `` .ds S" '' .ds N" `` .ds T" '' .ds L' ` .ds R' ' .ds M' ` .ds S' ' .ds N' ` .ds T' ' .ds PI \(*p 'br\} .\" If the F register is turned on, we'll generate .\" index entries out stderr for the following things: .\" TH Title .\" SH Header .\" Sh Subsection .\" Ip Item .\" X<> Xref (embedded .\" Of course, you have to process the output yourself .\" in some meaninful fashion. .if \nF \{ .de IX .tm Index:\\$1\t\\n%\t"\\$2" .. .nr % 0 .rr F .\} .TH sudo 8 "1.5.7" "5/Nov/98" "MAINTENANCE COMMANDS" .UC .if n .hy 0 .if n .na .ds C+ C\v'-.1v'\h'-1p'\s-2+\h'-1p'+\s0\v'.1v'\h'-1p' .de CQ \" put $1 in typewriter font .ft CW 'if n "\c 'if t \\&\\$1\c 'if n \\&\\$1\c 'if n \&" \\&\\$2 \\$3 \\$4 \\$5 \\$6 \\$7 '.ft R .. .\" @(#)ms.acc 1.5 88/02/08 SMI; from UCB 4.2 . \" AM - accent mark definitions .bd B 3 . \" fudge factors for nroff and troff .if n \{\ . ds #H 0 . ds #V .8m . ds #F .3m . ds #[ \f1 . ds #] \fP .\} .if t \{\ . ds #H ((1u-(\\\\n(.fu%2u))*.13m) . ds #V .6m . ds #F 0 . ds #[ \& . ds #] \& .\} . \" simple accents for nroff and troff .if n \{\ . ds ' \& . ds ` \& . ds ^ \& . ds , \& . ds ~ ~ . ds ? ? . ds ! ! . ds / . ds q .\} .if t \{\ . ds ' \\k:\h'-(\\n(.wu*8/10-\*(#H)'\'\h"|\\n:u" . ds ` \\k:\h'-(\\n(.wu*8/10-\*(#H)'\`\h'|\\n:u' . ds ^ \\k:\h'-(\\n(.wu*10/11-\*(#H)'^\h'|\\n:u' . ds , \\k:\h'-(\\n(.wu*8/10)',\h'|\\n:u' . ds ~ \\k:\h'-(\\n(.wu-\*(#H-.1m)'~\h'|\\n:u' . ds ? \s-2c\h'-\w'c'u*7/10'\u\h'\*(#H'\zi\d\s+2\h'\w'c'u*8/10' . ds ! \s-2\(or\s+2\h'-\w'\(or'u'\v'-.8m'.\v'.8m' . ds / \\k:\h'-(\\n(.wu*8/10-\*(#H)'\z\(sl\h'|\\n:u' . 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' .\} . \" troff and (daisy-wheel) nroff accents .ds : \\k:\h'-(\\n(.wu*8/10-\*(#H+.1m+\*(#F)'\v'-\*(#V'\z.\h'.2m+\*(#F'.\h'|\\n:u'\v'\*(#V' .ds 8 \h'\*(#H'\(*b\h'-\*(#H' .ds v \\k:\h'-(\\n(.wu*9/10-\*(#H)'\v'-\*(#V'\*(#[\s-4v\s0\v'\*(#V'\h'|\\n:u'\*(#] .ds _ \\k:\h'-(\\n(.wu*9/10-\*(#H+(\*(#F*2/3))'\v'-.4m'\z\(hy\v'.4m'\h'|\\n:u' .ds . \\k:\h'-(\\n(.wu*8/10)'\v'\*(#V*4/10'\z.\v'-\*(#V*4/10'\h'|\\n:u' .ds 3 \*(#[\v'.2m'\s-2\&3\s0\v'-.2m'\*(#] .ds o \\k:\h'-(\\n(.wu+\w'\(de'u-\*(#H)/2u'\v'-.3n'\*(#[\z\(de\v'.3n'\h'|\\n:u'\*(#] .ds d- \h'\*(#H'\(pd\h'-\w'~'u'\v'-.25m'\f2\(hy\fP\v'.25m'\h'-\*(#H' .ds D- D\\k:\h'-\w'D'u'\v'-.11m'\z\(hy\v'.11m'\h'|\\n:u' .ds th \*(#[\v'.3m'\s+1I\s-1\v'-.3m'\h'-(\w'I'u*2/3)'\s-1o\s+1\*(#] .ds Th \*(#[\s+2I\s-2\h'-\w'I'u*3/5'\v'-.3m'o\v'.3m'\*(#] .ds ae a\h'-(\w'a'u*4/10)'e .ds Ae A\h'-(\w'A'u*4/10)'E .ds oe o\h'-(\w'o'u*4/10)'e .ds Oe O\h'-(\w'O'u*4/10)'E . \" corrections for vroff .if v .ds ~ \\k:\h'-(\\n(.wu*9/10-\*(#H)'\s-2\u~\d\s+2\h'|\\n:u' .if v .ds ^ \\k:\h'-(\\n(.wu*10/11-\*(#H)'\v'-.4m'^\v'.4m'\h'|\\n:u' . \" for low resolution devices (crt and lpr) .if \n(.H>23 .if \n(.V>19 \ \{\ . ds : e . ds 8 ss . ds v \h'-1'\o'\(aa\(ga' . ds _ \h'-1'^ . ds . \h'-1'. . ds 3 3 . ds o a . ds d- d\h'-1'\(ga . ds D- D\h'-1'\(hy . ds th \o'bp' . ds Th \o'LP' . ds ae ae . ds Ae AE . ds oe oe . ds Oe OE .\} .rm #[ #] #H #V #F C .SH "NAME" sudo \- execute a command as the superuser .SH "SYNOPSIS" \fBsudo\fR \fB\-V\fR | \fB\-h\fR | \fB\-l\fR | \fB\-v\fR | \fB\-k\fR | \fB\-s\fR | \fB\-H\fR | [ \fB\-b\fR ] | [ \fB\-p\fR prompt ] [ \fB\-u\fR username/#uid] \fIcommand\fR .SH "DESCRIPTION" \fBsudo\fR allows a permitted user to execute a \fIcommand\fR as the superuser (real and effective uid and gid are set to \f(CW0\fR and root's group as set in the passwd file respectively). .PP \fBsudo\fR determines who is an authorized user by consulting the file \fI/etc/sudoers\fR. By giving \fBsudo\fR the \f(CW-v\fR flag a user can update the time stamp without running a \fIcommand.\fR The password prompt itself will also time out if the password is not entered with N minutes (again, this is defined at installation time and defaults to 5 minutes). .PP If an unauthorized user executes \fBsudo\fR, mail will be sent from the user to the local authorities (defined at installation time). .PP \fBsudo\fR was designed to log via the 4.3 BSD \fIsyslog\fR\|(3) facility but can log to a file instead if so desired (or to both syslog and a file). .SH "OPTIONS" \fBsudo\fR accepts the following command line options: .Ip "-V" 4 The \f(CW-V\fR (\fIversion\fR) option causes \fBsudo\fR to print the version number and exit. .Ip "-l" 4 The \f(CW-l\fR (\fIlist\fR) option will list out the allowed and forbidden commands for the user on the current host. .Ip "-h" 4 The \f(CW-h\fR (\fIhelp\fR) option causes \fBsudo\fR to print the version of \fBsudo\fR and a usage message before exiting. .Ip "-v" 4 If given the \f(CW-v\fR (\fIvalidate\fR) option, \fBsudo\fR will update the user's timestamp file, prompting for a password if necessary. This extends the \fBsudo\fR timeout to for another N minutes (where N is defined at installation time and defaults to 5 minutes) but does not run a command. .Ip "-k" 4 The \f(CW-k\fR (\fIkill\fR) option to \fBsudo\fR removes the user's timestamp file, thus requiring a password the next time \fBsudo\fR is run. This option does not require a password and was added to allow a user to revoke \fBsudo\fR permissions from a .logout file. .Ip "-b" 4 The \f(CW-b\fR (\fIbackground\fR) option tells \fBsudo\fR to run the given command in the background. Note that if you use the \f(CW-b\fR option you cannot use shell job control to manipulate the command. .Ip "-p" 4 The \f(CW-p\fR (\fIprompt\fR) option allows you to override the default password prompt and use a custom one. If the password prompt contains the \f(CW%u\fR escape, \f(CW%u\fR will be replaced by the user's login name. Similarly, \f(CW%h\fR will be replaced by the local hostname. .Ip "-u" 4 The \f(CW-u\fR (\fIuser\fR) option causes sudo to run the specified command as a user other than \fIroot\fR. To specify a \fIuid\fR instead of a \fIusername\fR, use \*(L"#uid\*(R". .Ip "-s" 4 The \f(CW-s\fR (\fIshell\fR) option runs the shell specified by the \fI\s-1SHELL\s0\fR environment variable if it is set or the shell as specified in \fIpasswd\fR\|(5). .Ip "-H" 4 The \f(CW-H\fR (\fI\s-1HOME\s0\fR) option sets the \fI\s-1HOME\s0\fR environment variable to the homedir of the target user (root by default) as specified in \fIpasswd\fR\|(5). .Ip "--" 4 The \f(CW--\fR flag indicates that \fBsudo\fR should stop processing command line arguments. It is most useful in conjunction with the \f(CW-s\fR flag. .SH "RETURN VALUES" \fBsudo\fR quits with an exit value of 1 if there is a configuration/permission problem or if \fBsudo\fR cannot execute the given command. In the latter case the error string is printed to stderr via \fIperror\fR\|(3). If \fBsudo\fR cannot \fIstat\fR\|(2) one or more entries in the user's PATH the error is printed on stderr via \fIperror\fR\|(3). (If the directory does not exist or if it is not really a directory, the entry is ignored and no error is printed.) This should not happen under normal circumstances. The most common reason for \fIstat\fR\|(3) to return \*(L"permission denied\*(R" is if you are running an automounter and one of the directories in your PATH is on a machine that is currently unreachable. .SH "SECURITY NOTES" \fBsudo\fR tries to be safe when executing external commands. Variables that control how dynamic loading and binding is done can be used to subvert the program that \fBsudo\fR runs. To combat this the \f(CWLD_*\fR, \f(CWSHLIB_PATH\fR (HP\-UX only), \f(CWLIBPATH\fR (AIX only), and \f(CW_RLD_*\fR environment variables are removed from the environment passed on to all commands executed. \fBsudo\fR will also remove the \f(CWIFS\fR, \f(CWENV\fR, \f(CWBASH_ENV\fR and \f(CWKRB_CONF\fR variables as they too can pose a threat. .PP To prevent command spoofing, \fBsudo\fR checks "." and "" (both denoting current directory) last when searching for a command in the user's PATH (if one or both are in the PATH). Note, however, that the actual PATH environment variable is \fInot\fR modified and is passed unchanged to the program that \fBsudo\fR executes. .PP For security reasons, if your OS supports shared libraries, \fBsudo\fR should always be statically linked unless the dynamic loader disables user-defined library search paths for setuid programs. (Most modern dynamic loaders do this.) .PP \fBsudo\fR will check the ownership of its timestamp directory (\fI/var/run/sudo\fR or \fI/tmp/.odus\fR by default) and ignore the directory's contents if it is not owned by root and only read, writable, and executable by root. On systems that allow users to give files away to root (via chown), if the timestamp directory is located in a directory writable by anyone (ie: \fI/tmp\fR), it is possible for a user to create the timestamp directory before \fBsudo\fR is run. However, because \fBsudo\fR checks the ownership and mode of the directory, the only damage that can be done is to \*(L"hide\*(R" files by putting them in the timestamp dir. This is unlikely to happen since once the timestamp dir is owned by root and inaccessible by any other user the user placing files there would be unable to get them back out. To get around this issue you can use a directory that is not world-writable for the timestamps (\fI/var/adm/sudo\fR for instance). .PP \f(CWsudo\fR will not honor timestamp files set far in the future. Timestamp files with a date greater than current_time + 2 * \f(CWTIMEOUT\fR will be ignored and sudo will log the anomaly. This is done to keep a user from creating his/her own timestamp file with a bogus date. .SH "FILES" .PP .Vb 1 \& /etc/sudoers file of authorized users. .Ve .SH "ENVIRONMENT VARIABLES" .PP .Vb 12 \& PATH Set to a sane value if SECURE_PATH is set \& SHELL Used to determine shell to run with -s option \& USER Set to the target user (root unless the -u option \& is specified) \& HOME In -s mode, set to homedir of root (or runas user) \& if built with the SHELL_SETS_HOME option \& SUDO_PROMPT Replaces the default password prompt \& SUDO_COMMAND Set to the command run by sudo \& SUDO_USER Set to the login of the user who invoked sudo \& SUDO_UID Set to the uid of the user who invoked sudo \& SUDO_GID Set to the gid of the user who invoked sudo \& SUDO_PS1 If set, PS1 will be set to its value .Ve .SH "AUTHORS" Many people have worked on \fBsudo\fR over the years, this version consists of code written primarily by: .PP .Vb 4 \& Jeff Nieusma \& David Hieb \& Todd Miller \& Chris Jepeway .Ve See the HISTORY file in the \fBsudo\fR distribution for more details. .PP Please send all bugs, comments, and changes to sudo-bugs@courtesan.com. .SH "DISCLAIMER" This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. .PP You should have received a copy of the GNU General Public License along with this program; if not, write to the Free Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. .SH "CAVEATS" There is no easy way to prevent a user from gaining a root shell if that user has access to commands allow shell escapes. .PP If users have sudo ALL there is nothing to prevent them from creating their own program that gives them a root shell regardless of any \*(L'!\*(R' elements in the user specification. .PP Running shell scripts via \fBsudo\fR can expose the same kernel bugs that make setuid shell scripts unsafe on some operating systems. .SH "SEE ALSO" \fIsudoers\fR\|(5), \fIvisudo\fR\|(8), \fIsu\fR\|(1). .rn }` '' .IX Title "sudo 8" .IX Name "sudo - execute a command as the superuser" .IX Header "NAME" .IX Header "SYNOPSIS" .IX Header "DESCRIPTION" .IX Header "OPTIONS" .IX Item "-V" .IX Item "-l" .IX Item "-h" .IX Item "-v" .IX Item "-k" .IX Item "-b" .IX Item "-p" .IX Item "-u" .IX Item "-s" .IX Item "-H" .IX Item "--" .IX Header "RETURN VALUES" .IX Header "SECURITY NOTES" .IX Header "FILES" .IX Header "ENVIRONMENT VARIABLES" .IX Header "AUTHORS" .IX Header "DISCLAIMER" .IX Header "CAVEATS" .IX Header "SEE ALSO"