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fixing up exit code documentation for lcpasswd and lcuserdel.  lcuseradd
useradd system call syntax still incorrect here.  I'm putting in more
of the setuid handling code. -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: # ( (0,"ok"),
   39: #   (1,"User ID mismatch.  This program must be run as user 'www'"),
   40: #   (2,"Error. Too many other simultaneous password change requests being made."),
   41: #   (3,"Error. Only one line should be entered into standard input."),
   42: #   (4,"Error. This program needs just 1 command-line argument (username).") )
   43: 
   44: # Security
   45: $ENV{'PATH'}=""; # Nullify path information.
   46: $ENV{'BASH_ENV'}=""; # Nullify shell environment information.
   47: 
   48: # Do not print error messages if there are command-line arguments
   49: my $noprint=0;
   50: if (@ARGV) {
   51:     $noprint=1;
   52: }
   53: 
   54: # Read in /etc/passwd, and make sure this process is running from user=www
   55: open (IN, "</etc/passwd");
   56: my @lines=<IN>;
   57: close IN;
   58: my $wwwid;
   59: for my $l (@lines) {
   60:     chop $l;
   61:     my @F=split(/\:/,$l);
   62:     if ($F[0] eq 'www') {$wwwid=$F[2];}
   63: }
   64: if ($wwwid!=$<) {
   65:     print("User ID mismatch.  This program must be run as user 'www'\n") unless $noprint;
   66:     exit 1;
   67: }
   68: &disable_root_capability;
   69: 
   70: # Handle case of another lcpasswd process
   71: unless (&try_to_lock("/tmp/lock_lcpasswd")) {
   72:     print "Error. Too many other simultaneous password change requests being made.\n" unless $noprint;
   73:     exit 4;
   74: }
   75: 
   76: # Gather input.  Should only be 1 value (user name).
   77: my @input;
   78: if (@ARGV==1) {
   79:     @input=@ARGV;
   80: }
   81: elsif (@ARGV) {
   82:     print("Error. This program needs just 1 command-line argument (username).\n") unless $noprint;
   83:     unlink('/tmp/lock_lcpasswd');
   84:     exit 2;
   85: }
   86: else {
   87:     @input=<>;
   88:     if (@input!=1) {
   89: 	print("Error. Only one line should be entered into standard input.\n") unless $noprint;
   90: 	unlink('/tmp/lock_lcpasswd');
   91: 	exit 3;
   92:     }
   93:     map {chop} @input;
   94: }
   95: 
   96: my ($username)=@input;
   97: $username=~/^(\w+)$/;
   98: my $safeusername=$1;
   99: 
  100: &enable_root_capability;
  101: 
  102: # By using the system userdel command:
  103: # Remove entry from /etc/passwd if it exists
  104: # Remove entry from /etc/groups if it exists
  105: # I surround with groupdel command to make absolutely sure the group definition disappears.
  106: system('/usr/sbin/groupdel 2>/dev/null',$safeusername); # ignore error message
  107: system('/usr/sbin/userdel 2>/dev/null',$safeusername); # ignore error message
  108: system('/usr/sbin/groupdel 2>/dev/null',$safeusername); # ignore error message
  109: 
  110: # Remove entry from /etc/smbpasswd if it exists
  111: my $oldsmbpasswd=`/bin/cat /etc/smbpasswd`;
  112: my $newsmbpasswd=`/bin/grep -v '^${safeusername}:' /etc/smbpasswd`;
  113: 
  114: if ($oldsmbpasswd ne $newsmbpasswd) {
  115:     open OUT,">/etc/smbpasswd";
  116:     print OUT $newsmbpasswd;
  117:     close OUT;
  118: }
  119: 
  120: # Change ownership on directory from username:username to www:www
  121: # This prevents subsequently added users from having access.
  122: 
  123: system('/bin/chown','-R','www:www',"/home/$safeusername");
  124: 
  125: &disable_root_capability;
  126: unlink("/tmp/lock_lcpasswd");
  127: exit 0;
  128: 
  129: # ----------------------------------------------------------- have setuid script run as root
  130: sub enable_root_capability {
  131:     if ($wwwid==$>) {
  132: 	($<,$>)=($>,$<);
  133: 	($(,$))=($),$();
  134:     }
  135:     else {
  136: 	# root capability is already enabled
  137:     }
  138:     return $>;
  139: }
  140: 
  141: # ----------------------------------------------------------- have setuid script run as www
  142: sub disable_root_capability {
  143:     if ($wwwid==$<) {
  144: 	($<,$>)=($>,$<);
  145: 	($(,$))=($),$();
  146:     }
  147:     else {
  148: 	# root capability is already disabled
  149:     }
  150: }
  151: 
  152: # ----------------------------------- make sure that another lcpasswd process isn't running
  153: sub try_to_lock {
  154:     my ($lockfile)=@_;
  155:     my $currentpid;
  156:     my $lastpid;
  157:     # Do not manipulate lock file as root
  158:     if ($>==0) {
  159: 	return 0;
  160:     }
  161:     # Try to generate lock file.
  162:     # Wait 3 seconds.  If same process id is in
  163:     # lock file, then assume lock file is stale, and
  164:     # go ahead.  If process id's fluctuate, try
  165:     # for a maximum of 10 times.
  166:     for (0..10) {
  167: 	if (-e $lockfile) {
  168: 	    open(LOCK,"<$lockfile");
  169: 	    $currentpid=<LOCK>;
  170: 	    close LOCK;
  171: 	    if ($currentpid==$lastpid) {
  172: 		last;
  173: 	    }
  174: 	    sleep 3;
  175: 	    $lastpid=$currentpid;
  176: 	}
  177: 	else {
  178: 	    last;
  179: 	}
  180: 	if ($_==10) {
  181: 	    return 0;
  182: 	}
  183:     }
  184:     open(LOCK,">$lockfile");
  185:     print LOCK $$;
  186:     close LOCK;
  187:     return 1;
  188: }
  189: 
  190: