--- loncom/Attic/lcuseradd 2000/10/29 22:50:56 1.5
+++ loncom/Attic/lcuseradd 2013/08/10 01:15:13 1.43
@@ -1,145 +1,375 @@
#!/usr/bin/perl
+
+# The Learning Online Network with CAPA
+#
+# lcuseradd - LON-CAPA setuid script to coordinate all actions
+# with adding a user with filesystem privileges (e.g. author)
#
-# lcuseradd
#
-# Scott Harrison
-# October 27, 2000
+# $Id: lcuseradd,v 1.43 2013/08/10 01:15:13 raeburn Exp $
+###
+
+###############################################################################
+## ##
+## ORGANIZATION OF THIS PERL SCRIPT ##
+## ##
+## 1. Description of script ##
+## 2. Invoking script (standard input) ##
+## 3. Example usage inside another piece of code ##
+## 4. Description of functions ##
+## 5. Exit codes ##
+## 6. Initializations ##
+## 7. Make sure this process is running from user=www ##
+## 8. Start running script with www permissions ##
+## 9. Handle case of another lcpasswd process (locking) ##
+## 10. Error-check input, need 3 values (user name, password 1, password 2) ##
+## 11. Start running script with root permissions ##
+## 12. Add user and make www a member of the user-specific group ##
+## 13. Set password ##
+## 14. Make final modifications to the user directory ##
+## 15. Exit script (unlock) ##
+## ##
+###############################################################################
use strict;
+use File::Find;
+
+# ------------------------------------------------------- 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.
-# It adds user entries to
-# /etc/passwd and /etc/groups.
+# 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.
-# Standard input usage
+# -------------- 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
+# Second line is DOMAIN
# Third line is PASSWORD
-
-# Command-line arguments [USERNAME] [PASSWORD] [PASSWORD]
+# Fourth line is PASSWORD
+# Fifth 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] [DOMAIN] [PASSWORD] [PASSWORD]
# Yes, but be very careful here (don't pass shell commands)
# and this is only supported to allow perl-system calls.
+#
+# Valid passwords must consist of the
+# ascii characters within the inclusive
+# range of 0x20 (32) to 0x7E (126).
+# These characters are:
+# 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).
+# ---------------------------------- Example usage inside another piece of code
# Usage within code
#
-# $exitcode=system("/home/httpd/perl/lcuseradd","NAME","PASSWORD1","PASSWORD2")/256;
-# print "uh-oh" if $exitcode;
-
-# These are the exit codes.
+# $Exitcode=
+# system("/home/httpd/perl/lcuseradd","NAME","DOMAIN","PASSWORD1","PASSWORD2")/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, ".
+# "password 1, password 2)."),
+# (3,"Error. Three lines should be entered into standard input."),
+# (4,"Error. Too many other simultaneous password change requests being ".
+# "made."),
+# (5,"Error. User $username does not exist."),
+# (6,"Error. Could not make www a member of the group \"$safeusername\"."),
+# (7,"Error. Root was not successfully enabled.),
+# (8,"Error. Cannot set password."),
+# (9,"Error. The user name specified has invalid characters."),
+# (10,"Error. A password entry had an invalid character."),
+# (11,"Error. User already exists.),
+# (12,"Error. Something went wrong with the addition of user ".
+# "\"$safeusername\"."),
+# (13,"Error. Password mismatch."),
+# (14, "Error filename is invalid"),
+# (15, "Error. Could not add home directory.")
+# ------------------------------------------------------------- Initializations
# Security
-$ENV{'PATH'}=""; # Nullify path information.
-$ENV{'BASH_ENV'}=""; # Nullify shell environment information.
+$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 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, "</etc/passwd");
-my @lines=<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;
- exit 1;
+# Do not print error messages.
+my $noprint=1;
+
+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);
}
+
+# ----------------------------------- Start running script with www permissions
&disable_root_capability;
-# Handle case of another lcpasswd process
+# --------------------------- 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;
- exit 4;
+ print "Error. Too many other simultaneous password change requests being ".
+ "made.\n" unless $noprint;
+ &Exit(4);
}
-# Gather input. Should be 3 values (user name, password 1, password 2).
+# ------- 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") unless $noprint;
+ if (@input < 3) {
+ print("Error. At least three lines should be entered into standard input.\n")
+ unless $noprint;
unlink('/tmp/lock_lcpasswd');
- exit 3;
+ &Exit(3);
}
- map {chop} @input;
+ foreach (@input) {chomp;}
}
-my ($username,$password1,$password2)=@input;
+my ($username,$domain,$password1,$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 $noprint;
-if ($password1 ne $password2) {
- print "Error. Password mismatch.\n";
+print "Domain = ".$domain."\n" unless $noprint;
+
+if (($username ne $safeusername) or ($safeusername!~/^[A-Za-z]/)) {
+ print "Error. The user name specified $username $safeusername has invalid characters.\n"
+ unless $noprint;
unlink('/tmp/lock_lcpasswd');
- exit 7;
+ &Exit(9);
+}
+my $pbad=0;
+foreach (split(//,$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" unless $noprint;
+ unlink('/tmp/lock_lcpasswd');
+ &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 the user if they are >not< in /etc/passwd.
+# Used to look for the ability to create a new directory for the
+# user, however that disallows authentication changes from i
+# internal->fs.. so just check the passwd file instead.
+#
+my $not_found = system("cut -d: -f1 /etc/passwd | grep -q \"^$safeusername\$\" ");
+if (!$not_found) {
+ print "Error user already exists\n" unless $noprint;
+ unlink('/tmp/lock_lcpasswd');
+ &Exit(11);
+}
+
+
+
+# -- Only add user if the two password arguments match.
+
+if ($password1 ne $password2) {
+ print "Error. Password mismatch.\n" unless $noprint;
+ unlink('/tmp/lock_lcpasswd');
+ &Exit(13);
+}
+print "enabling root\n" unless $noprint;
+# ---------------------------------- Start running script with root permissions
&enable_root_capability;
-# Add user entry to /etc/passwd and /etc/groups in such
-# a way that www is a member of the user-specific group
+# ------------------- Add group and user, and make www a member of the group
+# -- Add group
-if (system('/usr/sbin/useradd','-c','LON-CAPA user',$safeusername)) {
- print "Error. Something went wrong with the addition of user \"$safeusername\".\n";
+print "adding group: $safeusername \n" unless $noprint;
+my $status = system('/usr/sbin/groupadd', $safeusername);
+if ($status) {
+ print "Error. Something went wrong with the addition of group ".
+ "\"$safeusername\".\n" unless $noprint;
+ print "Final status of groupadd = $status\n";
unlink('/tmp/lock_lcpasswd');
- exit 5;
+ &Exit(12);
}
-if (system('/usr/sbin/usermod','-G',$safeusername,'www')) {
- print "Error. Could not make www a member of the group \"$safeusername\".\n";
+my $gid = getgrnam($safeusername);
+
+# -- Add user
+
+print "adding user: $safeusername \n" unless $noprint;
+my $status = system('/usr/sbin/useradd','-c','LON-CAPA user','-g',$gid,$safeusername);
+if ($status) {
+ print "Error. Something went wrong with the addition of user ".
+ "\"$safeusername\".\n" unless $noprint;
+ system("/usr/sbin/groupdel $safeusername");
+ print "Final status of useradd = $status\n";
unlink('/tmp/lock_lcpasswd');
- exit 6;
+ &Exit(12);
}
-# Set password with lcpasswd-style algorithm (which creates smbpasswd entry).
-# I cannot place a direct shell call to lcpasswd since I have to allow
-# for crazy characters in the password, and the setuid environment of perl
-# requires me to make everything safe.
+print "Done adding user\n" unless $noprint;
+# Make www a member of that user group.
+my $groups=`/usr/bin/groups www` or &Exit(6);
+# untaint
+my ($safegroups)=($groups=~/:\s*([\s\w]+)/);
+$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 www in user's 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 $noprint;
+ unlink('/tmp/lock_lcpasswd');
+ &Exit(6);
+}
+# ---------------------------------------------------------------- Set password
+# Set password with lcpasswd (which creates smbpasswd entry).
+unlink('/tmp/lock_lcpasswd');
+&disable_root_capability;
+($>,$<)=($wwwid,$wwwid);
+print "Opening lcpasswd pipeline\n" unless $noprint;
+open OUT,"|/home/httpd/perl/lcpasswd";
+print OUT $safeusername;
+print OUT "\n";
+print OUT $password1;
+print OUT "\n";
+print OUT $password1;
+print OUT "\n";
+close OUT;
+if ($?) {
+ print "abnormal Exit from close lcpasswd\n" unless $noprint;
+ &Exit(8);
+}
+($>,$<)=($wwwid,0);
+&enable_root_capability;
+
+# Check if home directory exists for user
+# If not, create one.
+if (!-e "/home/$safeusername") {
+ if (!mkdir("/home/$safeusername",0710)) {
+ print "Error. Could not add home directory for ".
+ "\"$safeusername\".\n" unless $noprint;
+ unlink('/tmp/lock_lcpasswd');
+ &Exit(15);
+ }
+}
-# ----------------------------------------------------------- have setuid script run as root
+# ---------------------------------------------------- Gracefull Apache Restart
+my $pidfile;
+if (-e '/var/run/httpd.pid') {
+ $pidfile = '/var/run/httpd.pid';
+} elsif (-e '/var/run/httpd2.pid') { #Apache 2 on SuSE 10.1 and SLES10
+ $pidfile = '/var/run/httpd2.pid';
+}
+
+if ($pidfile) {
+ print "lcuseradd Apache restart\n" unless $noprint;
+ open(PID,"<$pidfile");
+ my $pid=<PID>;
+ close(PID);
+ $pid=~ /(\D+)/;
+ my $safepid = $1;
+ if ($pid) {
+ system('kill','-USR1',"$safepid");
+ }
+}
+# -------------------------------------------------------- Exit script
+print "lcuseradd Exiting\n" unless $noprint;
+&disable_root_capability;
+&Exit(0);
+
+# ---------------------------------------------- Have setuid script run as root
sub enable_root_capability {
if ($wwwid==$>) {
- ($<,$>)=($>,$<);
- ($(,$))=($),$();
- }
- else {
+ ($<,$>)=($>,0);
+ ($(,$))=($),0);
+ } else {
# root capability is already enabled
}
+ if ($wwwid == $>) {
+ print("Failed to become root\n") unless $noprint;
+ } else {
+ print("Became root\n") unless $noprint;
+ }
return $>;
}
-# ----------------------------------------------------------- have setuid script run as www
+# ----------------------------------------------- Have setuid script run as www
sub disable_root_capability {
if ($wwwid==$<) {
($<,$>)=($>,$<);
($(,$))=($),$();
- }
- else {
+ } else {
# root capability is already disabled
}
}
-# ----------------------------------- make sure that another lcpasswd process isn't running
+# ----------------------- Make sure that another lcpasswd process isn't running
sub try_to_lock {
my ($lockfile)=@_;
my $currentpid;
@@ -163,8 +393,7 @@ sub try_to_lock {
}
sleep 3;
$lastpid=$currentpid;
- }
- else {
+ } else {
last;
}
if ($_==10) {
@@ -176,3 +405,70 @@ sub try_to_lock {
close LOCK;
return 1;
}
+# Called by File::Find::find for each file examined.
+#
+# Untaint the file and, if it is a directory,
+# chmod it to 02770
+#
+sub set_permission {
+ $File::Find::name =~ /^(.*)$/;
+ my $safe_name = $1; # Untainted filename...
+
+ print "$safe_name" unless $noprint;
+ if(-d $safe_name) {
+ print " - directory" unless $noprint;
+ chmod(02770, $safe_name);
+ }
+ print "\n" unless $noprint;
+
+}
+
+#-------------------------- Exit...
+#
+# Write the file if the error_file is defined. Regardless
+# Exit with the status code.
+#
+sub Exit {
+ my ($code) = @_; # Status code.
+
+ # TODO: Ensure the error file is owned/deletable by www:www:
+
+ &disable_root_capability(); # We run unprivileged to write the error file.
+
+ 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
+
+lcuseradd - LON-CAPA setuid script to coordinate all actions
+ with adding a user with filesystem privileges (e.g. author)
+
+=head1 DESCRIPTION
+
+lcuseradd - LON-CAPA setuid script to coordinate all actions
+ with adding a user with filesystem privileges (e.g. author)
+
+=head1 README
+
+lcuseradd - LON-CAPA setuid script to coordinate all actions
+ with adding a user with filesystem privileges (e.g. author)
+
+=head1 PREREQUISITES
+
+=head1 COREQUISITES
+
+=pod OSNAMES
+
+linux
+
+=pod SCRIPT CATEGORIES
+
+LONCAPA/Administrative
+
+=cut