version 1.1, 2000/10/27 23:42:33
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version 1.12, 2000/10/30 03:37:51
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# lcuserdel |
# lcuserdel |
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# Scott Harrison |
# Scott Harrison |
# October 27, 2000 |
# SH: October 27, 2000 |
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# SH: October 28, 2000 |
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# SH: October 29, 2000 |
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use strict; |
use strict; |
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# This script is a setuid script that should |
# This script is a setuid script (chmod 6755) that should |
# be run by user 'www'. It DOES NOT delete directories. |
# be run by user 'www'. It DOES NOT delete directories. |
# All it does is remove a user's entries from |
# All it does is remove a user's entries from |
# /etc/passwd, /etc/groups, and /etc/smbpasswd. |
# /etc/passwd, /etc/groups, and /etc/smbpasswd. |
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# It also disables user directory access by making the directory |
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# to be owned by user=www (as opposed to the former "username"). |
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# This command only returns an error if it is |
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# invoked incorrectly (by passing bad command-line arguments, etc). |
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# This script works under the same process control mechanism |
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# as lcuseradd and lcpasswd, to make sure that only one of these |
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# processes is running at any one time on the system. |
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# Standard input usage |
# Standard input usage |
# First line is USERNAME |
# First line is USERNAME |
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# Valid user names must consist of ascii |
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# characters that are alphabetical characters |
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# (A-Z,a-z), numeric (0-9), or the underscore |
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# mark (_). (Essentially, the perl regex \w). |
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# Command-line arguments [USERNAME] |
# Command-line arguments [USERNAME] |
# Yes, but be very careful here (don't pass shell commands) |
# Yes, but be very careful here (don't pass shell commands) |
# and this is only supported to allow perl-system calls. |
# and this is only supported to allow perl-system calls. |
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# Usage within code |
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# |
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# $exitcode=system("/home/httpd/perl/lcuserdel","NAME")/256; |
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# print "uh-oh" if $exitcode; |
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# These are the exit codes. |
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# ( (0,"ok"), |
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# (1,"User ID mismatch. This program must be run as user 'www'"), |
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# (2,"Error. This program needs just 1 command-line argument (username).") ) |
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# (3,"Error. Only one line should be entered into standard input."), |
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# (4,"Error. Too many other simultaneous password change requests being made."), |
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# (5,"Error. The user name specified has invalid characters.") ) |
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# Security |
# Security |
$ENV{'PATH'}=""; # Nullify path information. |
$ENV{'PATH'}=""; # Nullify path information. |
$ENV{'BASH_ENV'}=""; # Nullify shell environment information. |
$ENV{'BASH_ENV'}=""; # Nullify shell environment information. |
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# Do not print error messages if there are command-line arguments |
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my $noprint=0; |
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if (@ARGV) { |
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$noprint=1; |
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} |
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# Read in /etc/passwd, and make sure this process is running from user=www |
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open (IN, "</etc/passwd"); |
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my @lines=<IN>; |
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close IN; |
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my $wwwid; |
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for my $l (@lines) { |
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chop $l; |
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my @F=split(/\:/,$l); |
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if ($F[0] eq 'www') {$wwwid=$F[2];} |
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} |
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if ($wwwid!=$<) { |
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print("User ID mismatch. This program must be run as user 'www'\n") unless $noprint; |
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exit 1; |
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} |
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&disable_root_capability; |
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# Handle case of another lcpasswd process |
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unless (&try_to_lock("/tmp/lock_lcpasswd")) { |
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print "Error. Too many other simultaneous password change requests being made.\n" unless $noprint; |
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exit 4; |
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} |
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# Gather input. Should only be 1 value (user name). |
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my @input; |
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if (@ARGV==1) { |
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@input=@ARGV; |
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} |
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elsif (@ARGV) { |
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print("Error. This program needs just 1 command-line argument (username).\n") unless $noprint; |
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unlink('/tmp/lock_lcpasswd'); |
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exit 2; |
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} |
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else { |
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@input=<>; |
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if (@input!=1) { |
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print("Error. Only one line should be entered into standard input.\n") unless $noprint; |
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unlink('/tmp/lock_lcpasswd'); |
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exit 3; |
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} |
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map {chop} @input; |
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} |
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my ($username)=@input; |
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$username=~/^(\w+)$/; |
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my $safeusername=$1; |
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if ($username ne $safeusername) { |
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print "Error. The user name specified has invalid characters.\n"; |
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unlink('/tmp/lock_lcpasswd'); |
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exit 5; |
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} |
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&enable_root_capability; |
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# By using the system userdel command: |
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# Remove entry from /etc/passwd if it exists |
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# Remove entry from /etc/groups if it exists |
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# I surround with groupdel command to make absolutely sure the group definition disappears. |
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system('/usr/sbin/groupdel',$safeusername); # ignore error message |
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system('/usr/sbin/userdel',$safeusername); # ignore error message |
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system('/usr/sbin/groupdel',$safeusername); # ignore error message |
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# Remove entry from /etc/smbpasswd if it exists |
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my $oldsmbpasswd=`/bin/cat /etc/smbpasswd`; |
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my $newsmbpasswd=`/bin/grep -v '^${safeusername}:' /etc/smbpasswd`; |
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if ($oldsmbpasswd ne $newsmbpasswd) { |
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open OUT,">/etc/smbpasswd"; |
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print OUT $newsmbpasswd; |
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close OUT; |
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} |
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# Change ownership on directory from username:username to www:www |
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# This prevents subsequently added users from having access. |
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system('/bin/chown','-R','www:www',"/home/$safeusername"); |
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&disable_root_capability; |
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unlink("/tmp/lock_lcpasswd"); |
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exit 0; |
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# ----------------------------------------------------------- have setuid script run as root |
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sub enable_root_capability { |
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if ($wwwid==$>) { |
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($<,$>)=($>,$<); |
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($(,$))=($),$(); |
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} |
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else { |
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# root capability is already enabled |
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} |
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return $>; |
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} |
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# ----------------------------------------------------------- have setuid script run as www |
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sub disable_root_capability { |
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if ($wwwid==$<) { |
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($<,$>)=($>,$<); |
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($(,$))=($),$(); |
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} |
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else { |
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# root capability is already disabled |
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} |
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} |
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# ----------------------------------- make sure that another lcpasswd process isn't running |
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sub try_to_lock { |
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my ($lockfile)=@_; |
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my $currentpid; |
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my $lastpid; |
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# Do not manipulate lock file as root |
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if ($>==0) { |
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return 0; |
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} |
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# Try to generate lock file. |
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# Wait 3 seconds. If same process id is in |
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# lock file, then assume lock file is stale, and |
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# go ahead. If process id's fluctuate, try |
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# for a maximum of 10 times. |
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for (0..10) { |
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if (-e $lockfile) { |
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open(LOCK,"<$lockfile"); |
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$currentpid=<LOCK>; |
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close LOCK; |
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if ($currentpid==$lastpid) { |
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last; |
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} |
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sleep 3; |
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$lastpid=$currentpid; |
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} |
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else { |
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last; |
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} |
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if ($_==10) { |
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return 0; |
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} |
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} |
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open(LOCK,">$lockfile"); |
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print LOCK $$; |
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close LOCK; |
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return 1; |
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} |
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