--- loncom/lcuserdel 2000/10/27 23:42:33 1.1
+++ loncom/lcuserdel 2000/10/30 02:31:45 1.10
@@ -3,25 +3,198 @@
# lcuserdel
#
# Scott Harrison
-# October 27, 2000
+# SH: October 27, 2000
+# SH: October 28, 2000
+# SH: October 29, 2000
use strict;
-# 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.
# All it does is remove a user's entries from
# /etc/passwd, /etc/groups, and /etc/smbpasswd.
-
-
+# It also disables user directory access by making the directory
+# to be owned by user=www (as opposed to the former "username").
+# This command only returns an error if it is
+# invoked incorrectly (by passing bad command-line arguments, etc).
+
+# 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.
# Standard input usage
# First line is USERNAME
+# 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).
+
# Command-line arguments [USERNAME]
# Yes, but be very careful here (don't pass shell commands)
# and this is only supported to allow perl-system calls.
+# Usage within code
+#
+# $exitcode=system("/home/httpd/perl/lcuserdel","NAME")/256;
+# print "uh-oh" if $exitcode;
+
+# These are the exit codes.
+# ( (0,"ok"),
+# (1,"User ID mismatch. This program must be run as user 'www'"),
+# (2,"Error. Too many other simultaneous password change requests being made."),
+# (3,"Error. Only one line should be entered into standard input."),
+# (4,"Error. This program needs just 1 command-line argument (username).") )
+
# Security
$ENV{'PATH'}=""; # Nullify path information.
$ENV{'BASH_ENV'}=""; # Nullify shell environment information.
+# 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;
+}
+&disable_root_capability;
+
+# Handle case of another lcpasswd process
+unless (&try_to_lock("/tmp/lock_lcpasswd")) {
+ print "Error. Too many other simultaneous password change requests being made.\n" unless $noprint;
+ exit 4;
+}
+
+# Gather input. Should only be 1 value (user name).
+my @input;
+if (@ARGV==1) {
+ @input=@ARGV;
+}
+elsif (@ARGV) {
+ print("Error. This program needs just 1 command-line argument (username).\n") unless $noprint;
+ unlink('/tmp/lock_lcpasswd');
+ exit 2;
+}
+else {
+ @input=<>;
+ if (@input!=1) {
+ print("Error. Only one line should be entered into standard input.\n") unless $noprint;
+ unlink('/tmp/lock_lcpasswd');
+ exit 3;
+ }
+ map {chop} @input;
+}
+
+my ($username)=@input;
+$username=~/^(\w+)$/;
+my $safeusername=$1;
+if ($username ne $safeusername) {
+ print "Error. The user name specified has invalid characters.\n";
+ unlink('/tmp/lock_lcpasswd');
+ exit 9;
+}
+
+&enable_root_capability;
+
+# By using the system userdel command:
+# Remove entry from /etc/passwd if it exists
+# Remove entry from /etc/groups if it exists
+# I surround with groupdel command to make absolutely sure the group definition disappears.
+system('/usr/sbin/groupdel 2>/dev/null',$safeusername); # ignore error message
+system('/usr/sbin/userdel 2>/dev/null',$safeusername); # ignore error message
+system('/usr/sbin/groupdel 2>/dev/null',$safeusername); # ignore error message
+
+# Remove entry from /etc/smbpasswd if it exists
+my $oldsmbpasswd=`/bin/cat /etc/smbpasswd`;
+my $newsmbpasswd=`/bin/grep -v '^${safeusername}:' /etc/smbpasswd`;
+
+if ($oldsmbpasswd ne $newsmbpasswd) {
+ open OUT,">/etc/smbpasswd";
+ print OUT $newsmbpasswd;
+ close OUT;
+}
+
+# Change ownership on directory from username:username to www:www
+# This prevents subsequently added users from having access.
+
+system('/bin/chown','-R','www:www',"/home/$safeusername");
+
+&disable_root_capability;
+unlink("/tmp/lock_lcpasswd");
+exit 0;
+
+# ----------------------------------------------------------- have setuid script run as root
+sub enable_root_capability {
+ if ($wwwid==$>) {
+ ($<,$>)=($>,$<);
+ ($(,$))=($),$();
+ }
+ else {
+ # root capability is already enabled
+ }
+ return $>;
+}
+
+# ----------------------------------------------------------- have setuid script run as www
+sub disable_root_capability {
+ if ($wwwid==$<) {
+ ($<,$>)=($>,$<);
+ ($(,$))=($),$();
+ }
+ else {
+ # root capability is already disabled
+ }
+}
+
+# ----------------------------------- make sure that another lcpasswd process isn't running
+sub try_to_lock {
+ my ($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
+ # go ahead. If process id's fluctuate, try
+ # for a maximum of 10 times.
+ for (0..10) {
+ if (-e $lockfile) {
+ open(LOCK,"<$lockfile");
+ $currentpid=<LOCK>;
+ close LOCK;
+ if ($currentpid==$lastpid) {
+ last;
+ }
+ sleep 3;
+ $lastpid=$currentpid;
+ }
+ else {
+ last;
+ }
+ if ($_==10) {
+ return 0;
+ }
+ }
+ open(LOCK,">$lockfile");
+ print LOCK $$;
+ close LOCK;
+ return 1;
+}
+
+