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the script is complete now, but there remain some syntax errors
upon program execution -Scott

    1: #!/usr/bin/perl
    2: #
    3: # lcuserdel
    4: #
    5: # Scott Harrison
    6: # SH: October 27, 2000
    7: # SH: October 28, 2000
    8: # SH: October 29, 2000
    9: 
   10: use strict;
   11: 
   12: # This script is a setuid script (chmod 6755) that should
   13: # be run by user 'www'.  It DOES NOT delete directories.
   14: # All it does is remove a user's entries from
   15: # /etc/passwd, /etc/groups, and /etc/smbpasswd.
   16: # It also disables user directory access by making the directory
   17: # to be owned by user=www (as opposed to the former "username").
   18: # This command only returns an error if it is
   19: # invoked incorrectly (by passing bad command-line arguments, etc).
   20: 
   21: # This script works under the same process control mechanism
   22: # as lcuseradd and lcpasswd, to make sure that only one of these
   23: # processes is running at any one time on the system.
   24: 
   25: # Standard input usage
   26: # First line is USERNAME
   27: 
   28: # Command-line arguments [USERNAME]
   29: # Yes, but be very careful here (don't pass shell commands)
   30: # and this is only supported to allow perl-system calls.
   31: 
   32: # Usage within code
   33: #
   34: # $exitcode=system("/home/httpd/perl/lcuserdel","NAME")/256;
   35: # print "uh-oh" if $exitcode;
   36: 
   37: # These are the exit codes.
   38: 
   39: # Security
   40: $ENV{'PATH'}=""; # Nullify path information.
   41: $ENV{'BASH_ENV'}=""; # Nullify shell environment information.
   42: 
   43: # Do not print error messages if there are command-line arguments
   44: my $noprint=0;
   45: if (@ARGV) {
   46:     $noprint=1;
   47: }
   48: 
   49: # Read in /etc/passwd, and make sure this process is running from user=www
   50: open (IN, "</etc/passwd");
   51: my @lines=<IN>;
   52: close IN;
   53: my $wwwid;
   54: for my $l (@lines) {
   55:     chop $l;
   56:     my @F=split(/\:/,$l);
   57:     if ($F[0] eq 'www') {$wwwid=$F[2];}
   58: }
   59: if ($wwwid!=$<) {
   60:     print("User ID mismatch.  This program must be run as user 'www'\n") unless $noprint;
   61:     exit 1;
   62: }
   63: &disable_root_capability;
   64: 
   65: # Handle case of another lcpasswd process
   66: unless (&try_to_lock("/tmp/lock_lcpasswd")) {
   67:     print "Error. Too many other simultaneous password change requests being made.\n" unless $noprint;
   68:     exit 4;
   69: }
   70: 
   71: # Gather input.  Should only be 1 value (user name).
   72: my @input;
   73: if (@ARGV==1) {
   74:     @input=@ARGV;
   75: }
   76: elsif (@ARGV) {
   77:     print("Error. This program needs just 1 command-line argument (username).\n") unless $noprint;
   78:     exit 2;
   79: }
   80: else {
   81:     @input=<>;
   82:     if (@input!=1) {
   83: 	print("Error. Only one line should be entered into standard input.\n") unless $noprint;
   84: 	exit 3;
   85:     }
   86:     map {chop} @input;
   87: }
   88: 
   89: my ($username)=@input;
   90: $username=~/^(\w+)$/;
   91: my $safeusername=$1;
   92: 
   93: &enable_root_capability;
   94: 
   95: # By using the system userdel command:
   96: # Remove entry from /etc/passwd if it exists
   97: # Remove entry from /etc/groups if it exists
   98: system('/usr/sbin/userdel',$safeusername); # ignore error message
   99: system('/usr/sbin/groupdel',$safeusername); # ignore error message
  100: 
  101: # Remove entry from /etc/smbpasswd if it exists
  102: my $oldsmbpasswd=`/bin/cat /etc/smbpasswd`;
  103: my $newsmbpasswd=`/bin/grep -v '^${safeusername}:' /etc/smbpasswd`;
  104: 
  105: if ($oldsmbpasswd ne $newsmbpasswd) {
  106: open OUT,">/etc/smbpasswd";
  107: print OUT $newsmbpasswd;
  108: close OUT;
  109: 
  110: # Change ownership on directory from username:username to www:www
  111: # This prevents subsequently added users from having access.
  112: 
  113: system('/bin/chown','-R','www:www',"/home/$safeusername");
  114: 
  115: &disable_root_capability;
  116: unlink("/tmp/lock_lcpasswd");
  117: exit 0;
  118: 
  119: # ----------------------------------------------------------- have setuid script run as root
  120: sub enable_root_capability {
  121:     if ($wwwid==$>) {
  122: 	($<,$>)=($>,$<);
  123: 	($(,$))=($),$();
  124:     }
  125:     else {
  126: 	# root capability is already enabled
  127:     }
  128:     return $>;
  129: }
  130: 
  131: # ----------------------------------------------------------- have setuid script run as www
  132: sub disable_root_capability {
  133:     if ($wwwid==$<) {
  134: 	($<,$>)=($>,$<);
  135: 	($(,$))=($),$();
  136:     }
  137:     else {
  138: 	# root capability is already disabled
  139:     }
  140: }
  141: 
  142: # ----------------------------------- make sure that another lcpasswd process isn't running
  143: sub try_to_lock {
  144:     my ($lockfile)=@_;
  145:     my $currentpid;
  146:     my $lastpid;
  147:     # Do not manipulate lock file as root
  148:     if ($>==0) {
  149: 	return 0;
  150:     }
  151:     # Try to generate lock file.
  152:     # Wait 3 seconds.  If same process id is in
  153:     # lock file, then assume lock file is stale, and
  154:     # go ahead.  If process id's fluctuate, try
  155:     # for a maximum of 10 times.
  156:     for (0..10) {
  157: 	if (-e $lockfile) {
  158: 	    open(LOCK,"<$lockfile");
  159: 	    $currentpid=<LOCK>;
  160: 	    close LOCK;
  161: 	    if ($currentpid==$lastpid) {
  162: 		last;
  163: 	    }
  164: 	    sleep 3;
  165: 	    $lastpid=$currentpid;
  166: 	}
  167: 	else {
  168: 	    last;
  169: 	}
  170: 	if ($_==10) {
  171: 	    return 0;
  172: 	}
  173:     }
  174:     open(LOCK,">$lockfile");
  175:     print LOCK $$;
  176:     close LOCK;
  177:     return 1;
  178: }
  179: 
  180: