--- loncom/Attic/lcuseradd 2001/11/16 06:18:35 1.18 +++ loncom/Attic/lcuseradd 2004/08/06 10:29:37 1.28 @@ -5,12 +5,8 @@ # lcuseradd - LON-CAPA setuid script to coordinate all actions # with adding a user with filesystem privileges (e.g. author) # -# YEAR=2000 -# 10/27,10/29,10/30 Scott Harrison -# YEAR=2001 -# 10/21,11/13,11/15 Scott Harrison # -# $Id: lcuseradd,v 1.18 2001/11/16 06:18:35 harris41 Exp $ +# $Id: lcuseradd,v 1.28 2004/08/06 10:29:37 foxr Exp $ ### ############################################################################### @@ -40,18 +36,26 @@ use strict; # ------------------------------------------------------- Description of script # # This script is a setuid script that should -# be run by user 'www'. It creates a /home/USERNAME directory -# as well as a /home/USERNAME/public_html directory. +# be run by user 'www'. It creates a /home/USERNAME directory. # It adds a user to the unix system. # Passwords are set with lcpasswd. # www becomes a member of this user group. # -------------- Invoking script (standard input versus command-line arguments) +# Otherwise sensitive information will be available to ps-ers for +# a small but exploitable time window. # # Standard input (STDIN) usage # First line is USERNAME # Second line is PASSWORD # Third line is PASSWORD +# Fouth line is the name of a file to which an error code will be written. +# If the fourth line is omitted, no error file will be written. +# In either case, the program Exits with the code as its Exit status. +# The error file will just be a single line containing an +# error code. +# +# # # Command-line arguments [USERNAME] [PASSWORD] [PASSWORD] # Yes, but be very careful here (don't pass shell commands) @@ -75,9 +79,9 @@ use strict; # ---------------------------------- Example usage inside another piece of code # Usage within code # -# $exitcode= +# $Exitcode= # system("/home/httpd/perl/lcuseradd","NAME","PASSWORD1","PASSWORD2")/256; -# print "uh-oh" if $exitcode; +# print "uh-oh" if $Exitcode; # ---------------------------------------------------- Description of functions # enable_root_capability() : have setuid script run as root @@ -85,7 +89,7 @@ use strict; # try_to_lock() : make sure that another lcpasswd process isn't running # ------------------------------------------------------------------ Exit codes -# These are the exit codes. +# These are the Exit codes. # ( (0,"ok"), # (1,"User ID mismatch. This program must be run as user 'www'"), # (2,"Error. This program needs 3 command-line arguments (username, ". @@ -103,6 +107,7 @@ use strict; # (12,"Error. Something went wrong with the addition of user ". # "\"$safeusername\"."), # (13,"Error. Password mismatch."), +# (14, "Error filename is invalid") # ------------------------------------------------------------- Initializations # Security @@ -113,13 +118,19 @@ delete @ENV{qw(IFS CDPATH ENV BASH_ENV)} # Do not print error messages. my $noprint=1; +# Error file: + +my $error_file; # This is either the error file name or undef. + +print "In lcuseradd\n" unless $noprint; + # ----------------------------- Make sure this process is running from user=www my $wwwid=getpwnam('www'); &disable_root_capability; if ($wwwid!=$>) { print("User ID mismatch. This program must be run as user 'www'\n") unless $noprint; - exit 1; + &Exit(1); } # ----------------------------------- Start running script with www permissions @@ -129,86 +140,126 @@ if ($wwwid!=$>) { unless (&try_to_lock("/tmp/lock_lcpasswd")) { print "Error. Too many other simultaneous password change requests being ". "made.\n" unless $noprint; - exit 4; + &Exit(4); } # ------- Error-check input, need 3 values (user name, password 1, password 2). my @input; -if (@ARGV==3) { +if (@ARGV>=3) { @input=@ARGV; -} -elsif (@ARGV) { - print("Error. This program needs 3 command-line arguments (username, ". - "password 1, password 2).\n") unless $noprint; +} elsif (@ARGV) { + print("Error. This program needs at least 3 command-line arguments (username, ". + "password 1, password 2 [errorfile]).\n") unless $noprint; unlink('/tmp/lock_lcpasswd'); - exit 2; -} -else { + &Exit(2); +} else { @input=<>; - if (@input!=3) { - print("Error. Three lines should be entered into standard input.\n") + if (@input < 3) { + print("Error. At least three lines should be entered into standard input.\n") unless $noprint; unlink('/tmp/lock_lcpasswd'); - exit 3; + &Exit(3); } - map {chomp} @input; + foreach (@input) {chomp;} } -my ($username,$password1,$password2)=@input; +my ($username,$password1,$password2, $error_file)=@input; +print "Username = ".$username."\n" unless $noprint; $username=~/^(\w+)$/; +print "Username after substitution - ".$username unless $noprint; my $safeusername=$1; +print "Safe username = $safeusername \n" unless $noprint; + if (($username ne $safeusername) or ($safeusername!~/^[A-Za-z]/)) { - print "Error. The user name specified has invalid characters.\n" + print "Error. The user name specified $username $safeusername has invalid characters.\n" unless $noprint; unlink('/tmp/lock_lcpasswd'); - exit 9; + &Exit(9); } my $pbad=0; -map {if ((ord($_)<32)||(ord($_)>126)){$pbad=1;}} (split(//,$password1)); -map {if ((ord($_)<32)||(ord($_)>126)){$pbad=1;}} (split(//,$password2)); +foreach (split(//,$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"; + print "Error. A password entry had an invalid character.\n" unless $noprint; unlink('/tmp/lock_lcpasswd'); - exit 10; + &Exit(10); +} + +# +# Safe the filename. For our case, it must only have alpha, numeric, period +# and path sparators.. +# + +print "Error file is $error_file \n" unless $noprint; + +if($error_file) { + if($error_file =~ /^([(\w)(\d)\.\/]+)$/) { + print "Error file matched pattern $error_file : $1\n" unless $noprint; + my $safe_error_file = $1; # Untainted I think. + print "Error file after transform $safe_error_file\n" + unless $noprint; + if($error_file == $safe_error_file) { + $error_file = $safe_error_file; # untainted error_file. + } else { + $error_file =""; + print "Invalid error filename\n" unless $noprint; + Exit(14); + } + + } else { + $error_file=""; + print "Invalid error filename\n" unless $noprint; + Exit(14); + } } + # -- Only add user if we can create a brand new home directory (/home/username) if (-e "/home/$safeusername") { print "Error. User already exists.\n" unless $noprint; unlink('/tmp/lock_lcpasswd'); - exit 11; + &Exit(11); } # -- Only add user if the two password arguments match. + if ($password1 ne $password2) { print "Error. Password mismatch.\n" unless $noprint; unlink('/tmp/lock_lcpasswd'); - exit 13; + &Exit(13); } - +print "enabling root\n" unless $noprint; # ---------------------------------- Start running script with root permissions &enable_root_capability; # ------------------- Add user and make www a member of the user-specific group # -- Add user -if (system('/usr/sbin/useradd','-c','LON-CAPA user',$safeusername)) { + +print "adding user: $safeusername \n" unless $noprint; +my $status = system('/usr/sbin/useradd','-c','LON-CAPA user',$safeusername); +if ($status) { print "Error. Something went wrong with the addition of user ". "\"$safeusername\".\n" unless $noprint; + print "Final status of useradd = $status"; unlink('/tmp/lock_lcpasswd'); - exit 12; + &Exit(12); } - +print "Done adding user\n" unless $noprint; # Make www a member of that user group. -my $groups=`/usr/bin/groups www` or exit(6); +my $groups=`/usr/bin/groups www` or &Exit(6); +# untaint +my ($safegroups)=($groups=~/([\s\w]+)/); +$groups=$safegroups; chomp $groups; $groups=~s/^\S+\s+\:\s+//; my @grouplist=split(/\s+/,$groups); my @ugrouplist=grep {!/www|$safeusername/} @grouplist; my $gl=join(',',(@ugrouplist,$safeusername)); +print "Putting user in its own group\n" unless $noprint; if (system('/usr/sbin/usermod','-G',$gl,'www')) { print "Error. Could not make www a member of the group ". "\"$safeusername\".\n" unless $noprint; unlink('/tmp/lock_lcpasswd'); - exit 6; + &Exit(6); } # ---------------------------------------------------------------- Set password @@ -217,6 +268,7 @@ if (system('/usr/sbin/usermod','-G',$gl, unlink('/tmp/lock_lcpasswd'); &disable_root_capability; ($>,$<)=($wwwid,$wwwid); +print "Opening lcpasswd pipeline\n" unless $noprint; open OUT,"|/home/httpd/perl/lcpasswd"; print OUT $safeusername; print OUT "\n"; @@ -226,15 +278,19 @@ print OUT $password1; print OUT "\n"; close OUT; if ($?) { - exit 8; + print "abnormal Exit from close lcpasswd\n" unless $noprint; + &Exit(8); } ($>,$<)=($wwwid,0); &enable_root_capability; +# -- Don't add public_html... that can be added either by the user +# or by lchtmldir when the user is granted an authorship role. + # ------------------------------ Make final modifications to the user directory # -- Add a public_html file with a stand-in index.html file -# system('/bin/chmod','-R','0660',"/home/$safeusername"); + system('/bin/chmod','-R','0660',"/home/$safeusername"); system('/bin/chmod','0710',"/home/$safeusername"); mkdir "/home/$safeusername/public_html",0755; system('/bin/chmod','02770',"/home/$safeusername/public_html"); @@ -245,35 +301,37 @@ print OUT<$safeusername -

$safeusername

-

-Learning Online Network -

-

-This area provides for: -

- +

Construction Space

+

$safeusername

END close OUT; -system('/bin/chown','-R',"$safeusername:$safeusername","/home/$safeusername"); +print "lcuseradd ownership\n" unless $noprint; +system('/bin/chown','-R',"$safeusername:$safeusername","/home/$safeusername"); +# ---------------------------------------------------- Gracefull Apache Restart +if (-e '/var/run/httpd.pid') { + print "lcuseradd Apache restart\n" unless $noprint; + open(PID,'/var/run/httpd.pid'); + my $pid=; + close(PID); + my ($safepid)=($pid=~s/(\D+)//g); + if ($pid) { + system('kill','-USR1',"$safepid"); + } +} # -------------------------------------------------------- Exit script +print "lcuseradd Exiting\n" unless $noprint; &disable_root_capability; -exit 0; +&Exit(0); # ---------------------------------------------- Have setuid script run as root sub enable_root_capability { if ($wwwid==$>) { - ($<,$>)=($>,$<); - ($(,$))=($),$(); - } - else { + ($<,$>)=($>,0); + ($(,$))=($),0); + } else { # root capability is already enabled } return $>; @@ -284,8 +342,7 @@ sub disable_root_capability { if ($wwwid==$<) { ($<,$>)=($>,$<); ($(,$))=($),$(); - } - else { + } else { # root capability is already disabled } } @@ -314,8 +371,7 @@ sub try_to_lock { } sleep 3; $lastpid=$currentpid; - } - else { + } else { last; } if ($_==10) { @@ -327,6 +383,22 @@ sub try_to_lock { close LOCK; return 1; } +#-------------------------- Exit... +# +# Write the file if the error_file is defined. Regardless +# Exit with the status code. +# +sub Exit { + my ($code) = @_; # Status code. + + print "Exiting with status $code error file is $error_file\n" unless $noprint; + if($error_file) { + open(FH, ">$error_file"); + print FH "$code\n"; + close(FH); + } + exit $code; +} =head1 NAME