--- loncom/lcpasswd 2000/10/30 03:30:26 1.11 +++ loncom/lcpasswd 2010/10/12 10:33:47 1.22 @@ -1,29 +1,48 @@ #!/usr/bin/perl +# The Learning Online Network with CAPA # -# lcpasswd +# lcpasswd - LON-CAPA setuid script to synchronously change all +# filesystem-related passwords (samba, unix, etc) # -# Scott Harrison -# SH: October 27, 2000 -# SH: October 28, 2000 -# SH: October 29, 2000 +# YEAR=2002 +# 02/19 Matthew Hall +# +# $Id: lcpasswd,v 1.22 2010/10/12 10:33:47 foxr Exp $ +### + +############################################################################### +## ## +## ORGANIZATION OF THIS PERL SCRIPT ## +## ## +## 1. Description of script ## +## 2. Invoking script (standard input only) ## +## 3. Example usage inside another piece of code ## +## 4. Description of functions ## +## 5. Exit codes ## +## ## +############################################################################### use strict; +# ------------------------------------------------------- Description of script +# # This script is a setuid script that should # be run by user 'www'. This script allows # for synchronous entry of passwords into # both the /etc/passwd and the /etc/smbpasswd # files. - +# # This script works under the same process control mechanism # as lcuseradd and lcpasswd, to make sure that only one of these # processes is running at any one time on the system. +# --------------------------------------- Invoking script (standard input only) +# # Standard input usage # First line is USERNAME -# Second line is CURRENT PASSWORD +# Second line is NEW PASSWORD # Third line is NEW PASSWORD - +# # Valid passwords must consist of the # ascii characters within the inclusive # range of 0x20 (32) to 0x7E (126). @@ -31,176 +50,155 @@ use strict; # SPACE and # !"#$%&'()*+,-./0123456789:;<=>?@ABCDEFGHIJKLMNO # PQRSTUVWXYZ[\]^_`abcdefghijklmnopqrstuvwxyz{|}~ - +# # Valid user names must consist of ascii # characters that are alphabetical characters # (A-Z,a-z), numeric (0-9), or the underscore # mark (_). (Essentially, the perl regex \w). +# User names must begin with an alphabetical character +# (A-Z,a-z). -# Command-line arguments -# Yes, but be very careful here (don't pass shell commands) -# and this is only supported to allow perl-system calls. - -# Usage within code -# Note: NEVER run as system("/home/httpd/perl/lcpasswd NAME OLDPWD NEWPWD") -# -# $exitcode=system("/home/httpd/perl/lcpasswd","NAME","OLDPWD","NEWPWD")/256; -# print "uh-oh" if $exitcode; +# ---------------------------------------------------- Description of functions +# enable_root_capability() : have setuid script run as root +# disable_root_capability() : have setuid script run as www +# try_to_lock() : make sure that another lcpasswd process isn't running +# ------------------------------------------------------------------ Exit codes # These are the exit codes. # ( (0,"ok"), # (1,"User ID mismatch. This program must be run as user 'www'"), -# (2,"Error. This program needs 3 command-line arguments (username, old password, new password)."), +# (2,"Error. This program needs 3 command-line arguments (username, old ". +# password, new password)."), # (3,"Error. Three lines need to be entered into standard input."), -# (4,"Error. Too many other simultaneous password change requests being made."), +# (4,"Error. Too many other simultaneous password change requests being ". +# made."), # (5,"Error. User $username does not exist."), # (6,"Error. Invalid entry of current password."), # (7,"Error. Root was not successfully enabled."), -# (8,"Error. Cannot open /etc/passwd."), +# (8,"Error. Cannot set password."), # (9,"Error. The user name specified has invalid characters."), # (10,"Error. A password entry had an invalid character.") ) +# ------------------------------------------------------------- Initializations # Security -$ENV{'PATH'}='/bin:/usr/bin'; # Nullify path information except for what smbpasswd needs -$ENV{'BASH_ENV'}=''; # Nullify shell environment information. +$ENV{'PATH'}='/bin:/usr/bin:/usr/local/sbin:/home/httpd/perl'; # Nullify path + # information +delete @ENV{qw(IFS CDPATH ENV BASH_ENV)}; # nullify potential taints + +# Do not print error messages +my $noprint=1; + +print "In lcpasswd" unless $noprint; + +# ----------------------------- Make sure this process is running from user=www +my $wwwid=getpwnam('www'); -# Do not print error messages if there are command-line arguments -my $noprint=0; -if (@ARGV) { - $noprint=1; -} - -# Read in /etc/passwd, and make sure this process is running from user=www -open (IN, '; -close IN; -my $wwwid; -for my $l (@lines) { - chop $l; - my @F=split(/\:/,$l); - if ($F[0] eq 'www') {$wwwid=$F[2];} -} if ($wwwid!=$<) { - print("User ID mismatch. This program must be run as user 'www'\n") unless $noprint; + print("User ID mismatch. This program must be run as user 'www'\n") + unless $noprint; exit 1; } -&disable_root_capability; -# Handle case of another lcpasswd process +# ----------------------------------- Start running script with www permissions + + +# --------------------------- Handle case of another lcpasswd process (locking) unless (&try_to_lock('/tmp/lock_lcpasswd')) { - print "Error. Too many other simultaneous password change requests being made.\n" unless $noprint; + print "Error. Too many other simultaneous password change requests being ". + "made.\n" unless $noprint; exit 4; } -# Gather input. Should only be 3 values. +# ------- Error-check input, need 3 values (user name, password 1, password 2). my @input; -if (@ARGV==3) { - @input=@ARGV; -} -elsif (@ARGV) { - print("Error. This program needs 3 command-line arguments (username, old password, new password).\n") unless $noprint; +@input=<>; +if (@input!=3) { + print("Error. Three lines need to be entered into standard input.\n") + unless $noprint; unlink('/tmp/lock_lcpasswd'); - exit 2; -} -else { - @input=<>; - if (@input!=3) { - print("Error. Three lines need to be entered into standard input.\n") unless $noprint; - unlink('/tmp/lock_lcpasswd'); - exit 3; - } - map {chop} @input; + exit 3; } +foreach (@input) {chomp;} -my ($username,$oldpwd,$newpwd)=@input; +my ($username,$password1,$password2)=@input; $username=~/^(\w+)$/; my $safeusername=$1; -if ($username ne $safeusername) { +if (($username ne $safeusername) or ($safeusername!~/^[A-Za-z]/)) { print "Error. The user name specified has invalid characters.\n"; unlink('/tmp/lock_lcpasswd'); exit 9; } my $pbad=0; -map {if (($_<32)&&($_>126)){$pbad=1;}} (split(//,$oldpwd)); -map {if (($_<32)&&($_>126)){$pbad=1;}} (split(//,$newpwd)); +foreach (split(//,$password1)) {if ((ord($_)<32)||(ord($_)>126)){$pbad=1;}} +foreach (split(//,$password2)) {if ((ord($_)<32)||(ord($_)>126)){$pbad=1;}} if ($pbad) { print "Error. A password entry had an invalid character.\n"; unlink('/tmp/lock_lcpasswd'); exit 10; } -# Grab the line corresponding to username -my ($userid,$useroldcryptpwd); -my @F; my @U; -for my $l (@lines) { - @F=split(/\:/,$l); - if ($F[0] eq $username) {($userid,$useroldcryptpwd)=($F[2],$F[1]); @U=@F;} +# -- Only add user if the two password arguments match. +if ($password1 ne $password2) { + print "Error. Password mismatch.\n" unless $noprint; + unlink('/tmp/lock_lcpasswd'); + exit 13; } # Verify existence of user -if (!defined($userid)) { +unless(getpwnam($safeusername)) { print "Error. User $username does not exist.\n" unless $noprint; unlink('/tmp/lock_lcpasswd'); exit 5; } +&enable_root_capability; +($>,$<)=(0,0); -# Verify password entry -if (crypt($oldpwd,$useroldcryptpwd) ne $useroldcryptpwd) { - print "Error. Invalid entry of current password.\n" unless $noprint; - unlink('/tmp/lock_lcpasswd'); - exit 6; -} +print "Now $> , $< , -invoking pwchange with $safeusername $password1" + unless $noprint; +open OUT,"|pwchange $safeusername"; +print OUT $password1; +print OUT "\n"; +close OUT; +($>,$<)=(0,$wwwid); -# Construct new password entry (random salt) -my $newcryptpwd=crypt($newpwd,(join '', ('.', '/', 0..9, 'A'..'Z', 'a'..'z')[rand 64, rand 64])); -$U[1]=$newcryptpwd; -my $userline=join(':',@U); -my $rootid=&enable_root_capability; -if ($rootid!=0) { - print "Error. Root was not successfully enabled.\n" unless $noprint; - unlink('/tmp/lock_lcpasswd'); - exit 7; +print "pwchange done, back to uid $wwwid" unless $noprint; + +if ($?) { + exit 8; } -open PASSWORDFILE, '>/etc/passwd' or (print("Error. Cannot open /etc/passwd.\n") && unlink('/tmp/lock_lcpasswd') && exit(8)); -for my $l (@lines) { - @F=split(/\:/,$l); - if ($F[0] eq $username) {print PASSWORDFILE "$userline\n";} - else {print PASSWORDFILE "$l\n";} -} -close PASSWORDFILE; - -($>,$<)=(0,0); # fool smbpasswd here to think this is not a setuid environment -unless (-e '/etc/smbpasswd') { - open (OUT,'>/etc/smbpasswd'); close OUT; -} -my $smbexist=0; -open (IN, '; -close IN; -for my $l (@lines) { - chop $l; - my @F=split(/\:/,$l); - if ($F[0] eq $username) {$smbexist=1;} -} -unless ($smbexist) { - open(OUT,'>>/etc/smbpasswd'); - print OUT join(':',($safeusername,$userid,'XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX:XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX','','/home/'.$safeusername,'/bin/bash')) . "\n"; +my $userid=getpwnam($safeusername); + +if (-e '/usr/bin/smbpasswd') { + + ($>,$<)=(0,0); # fool smbpasswd here to think this is not a setuid + # environment + +# If the -a switch is put on the smbpasswd +# command line, either a new entry will be created or the old one +# will be used. +# Therefore the old strategy of looking for and adding a dummy entry is +# not needed... Finally, the smbpasswd file is in /etc/samba not +# /etc/smbpasswd as older versions of the script implied. + + print "Running smbpasswd" unless $noprint; + open(OUT,"|/usr/bin/smbpasswd -s -a $safeusername>/dev/null") or + die('cannot run smbpasswd'); + print OUT $password2; print OUT "\n"; + print OUT $password2; print OUT "\n"; close OUT; + $<=$wwwid; # unfool the program + print "smbpasswd done" unless $noprint; } -open(OUT,"|/usr/bin/smbpasswd -s $safeusername>/dev/null"); -print OUT $newpwd; print OUT "\n"; -print OUT $newpwd; print OUT "\n"; -close OUT; -$<=$wwwid; # unfool the program -&disable_root_capability; + + unlink('/tmp/lock_lcpasswd'); exit 0; -# ----------------------------------------------------------- have setuid script run as root +# ---------------------------------------------- have setuid script run as root sub enable_root_capability { if ($wwwid==$>) { - ($<,$>)=($>,$<); - ($(,$))=($),$(); + ($<,$>)=($>,0); + ($(,$))=($),0); } else { # root capability is already enabled @@ -208,7 +206,7 @@ sub enable_root_capability { return $>; } -# ----------------------------------------------------------- have setuid script run as www +# ----------------------------------------------- have setuid script run as www sub disable_root_capability { if ($wwwid==$<) { ($<,$>)=($>,$<); @@ -219,15 +217,12 @@ sub disable_root_capability { } } -# ----------------------------------- make sure that another lcpasswd process isn't running +# ----------------------- make sure that another lcpasswd process isn't running sub try_to_lock { my ($lockfile)=@_; my $currentpid; my $lastpid; - # Do not manipulate lock file as root - if ($>==0) { - return 0; - } + # Try to generate lock file. # Wait 3 seconds. If same process id is in # lock file, then assume lock file is stale, and @@ -256,3 +251,32 @@ sub try_to_lock { close LOCK; return 1; } + +=head1 NAME + +lcpasswd - LON-CAPA setuid script to synchronously change all + filesystem-related passwords (samba, unix, etc) + +=head1 DESCRIPTION + +LON-CAPA setuid script to synchronously change all +filesystem-related passwords (samba, unix, etc) + +=head1 README + +LON-CAPA setuid script to synchronously change all +filesystem-related passwords (samba, unix, etc) + +=head1 PREREQUISITES + +=head1 COREQUISITES + +=pod OSNAMES + +linux + +=pod SCRIPT CATEGORIES + +LONCAPA/Administrative + +=cut