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scripts are almost all working. lcuserdel still has some problems, and lcuseradd
doesn't get the permissions quite right yet.

    1: #!/usr/bin/perl
    2: #
    3: # lcuseradd
    4: #
    5: # Scott Harrison
    6: # SH: October 27, 2000
    7: # SH: October 29, 2000
    8: 
    9: use strict;
   10: 
   11: # This script is a setuid script that should
   12: # be run by user 'www'.  It creates a /home/USERNAME directory
   13: # as well as a /home/USERNAME/public_html directory.
   14: # It adds user entries to
   15: # /etc/passwd and /etc/groups.
   16: # Passwords are set with lcpasswd.
   17: # www becomes a member of this user group.
   18: 
   19: # Standard input usage
   20: # First line is USERNAME
   21: # Second line is PASSWORD
   22: # Third line is PASSWORD
   23: 
   24: # Valid passwords must consist of the
   25: # ascii characters within the inclusive
   26: # range of 0x20 (32) to 0x7E (126).
   27: # These characters are:
   28: # SPACE and
   29: # !"#$%&'()*+,-./0123456789:;<=>?@ABCDEFGHIJKLMNO
   30: # PQRSTUVWXYZ[\]^_`abcdefghijklmnopqrstuvwxyz{|}~
   31: 
   32: # Valid user names must consist of ascii
   33: # characters that are alphabetical characters
   34: # (A-Z,a-z), numeric (0-9), or the underscore
   35: # mark (_). (Essentially, the perl regex \w).
   36: 
   37: # Command-line arguments [USERNAME] [PASSWORD] [PASSWORD]
   38: # Yes, but be very careful here (don't pass shell commands)
   39: # and this is only supported to allow perl-system calls.
   40: 
   41: # Usage within code
   42: #
   43: # $exitcode=system("/home/httpd/perl/lcuseradd","NAME","PASSWORD1","PASSWORD2")/256;
   44: # print "uh-oh" if $exitcode;
   45: 
   46: # These are the exit codes.
   47: # ( (0,"ok"),
   48: # (1,"User ID mismatch.  This program must be run as user 'www'"),
   49: # (2,"Error. This program needs 3 command-line arguments (username, password 1, password 2)."),
   50: # (3,"Error. Three lines should be entered into standard input."),
   51: # (4,"Error. Too many other simultaneous password change requests being made."),
   52: # (5,"Error. User $username does not exist."),
   53: # (6,"Error. Could not make www a member of the group \"$safeusername\"."),
   54: # (7,"Error. Root was not successfully enabled.),
   55: # (8,"Error. Cannot open /etc/passwd."),
   56: # (9,"Error. The user name specified has invalid characters."),
   57: # (10,"Error. A password entry had an invalid character."),
   58: # (11,"Error. User already exists.),
   59: # (12,"Error. Something went wrong with the addition of user \"$safeusername\"."),
   60: # (13,"Error. Password mismatch."),
   61: 
   62: # Security
   63: $ENV{'PATH'}=""; # Nullify path information.
   64: $ENV{'BASH_ENV'}=""; # Nullify shell environment information.
   65: 
   66: # Do not print error messages if there are command-line arguments
   67: my $noprint=0;
   68: if (@ARGV) {
   69:     $noprint=1;
   70: }
   71: 
   72: # Read in /etc/passwd, and make sure this process is running from user=www
   73: open (IN, "</etc/passwd");
   74: my @lines=<IN>;
   75: close IN;
   76: my $wwwid;
   77: for my $l (@lines) {
   78:     chop $l;
   79:     my @F=split(/\:/,$l);
   80:     if ($F[0] eq 'www') {$wwwid=$F[2];}
   81: }
   82: if ($wwwid!=$<) {
   83:     print("User ID mismatch.  This program must be run as user 'www'\n") unless $noprint;
   84:     exit 1;
   85: }
   86: &disable_root_capability;
   87: 
   88: # Handle case of another lcpasswd process
   89: unless (&try_to_lock("/tmp/lock_lcpasswd")) {
   90:     print "Error. Too many other simultaneous password change requests being made.\n" unless $noprint;
   91:     exit 4;
   92: }
   93: 
   94: # Gather input.  Should be 3 values (user name, password 1, password 2).
   95: my @input;
   96: if (@ARGV==3) {
   97:     @input=@ARGV;
   98: }
   99: elsif (@ARGV) {
  100:     print("Error. This program needs 3 command-line arguments (username, password 1, password 2).\n") unless $noprint;
  101:     unlink('/tmp/lock_lcpasswd');
  102:     exit 2;
  103: }
  104: else {
  105:     @input=<>;
  106:     if (@input!=3) {
  107: 	print("Error. Three lines should be entered into standard input.\n") unless $noprint;
  108: 	unlink('/tmp/lock_lcpasswd');
  109: 	exit 3;
  110:     }
  111:     map {chop} @input;
  112: }
  113: 
  114: my ($username,$password1,$password2)=@input;
  115: $username=~/^(\w+)$/;
  116: my $safeusername=$1;
  117: if ($username ne $safeusername) {
  118:     print "Error. The user name specified has invalid characters.\n";
  119:     unlink('/tmp/lock_lcpasswd');
  120:     exit 9;
  121: }
  122: my $pbad=0;
  123: map {if ((ord($_)<32)||(ord($_)>126)){$pbad=1;}} (split(//,$password1));
  124: map {if ((ord($_)<32)||(ord($_)>126)){$pbad=1;}} (split(//,$password2));
  125: if ($pbad) {
  126:     print "Error. A password entry had an invalid character.\n";
  127:     unlink('/tmp/lock_lcpasswd');
  128:     exit 10;
  129: }
  130: 
  131: # Only add user if we can create a brand new home directory (/home/username).
  132: if (-e "/home/$safeusername") {
  133:     print "Error. User already exists.\n" unless $noprint;
  134:     unlink('/tmp/lock_lcpasswd');
  135:     exit 11;
  136: }
  137: 
  138: # Only add user if the two password arguments match.
  139: if ($password1 ne $password2) {
  140:     print "Error. Password mismatch.\n" unless $noprint;
  141:     unlink('/tmp/lock_lcpasswd');
  142:     exit 13;
  143: }
  144: 
  145: &enable_root_capability;
  146: 
  147: # Add user entry to /etc/passwd and /etc/groups in such
  148: # a way that www is a member of the user-specific group
  149: 
  150: if (system('/usr/sbin/useradd','-c','LON-CAPA user',$safeusername)) {
  151:     print "Error.  Something went wrong with the addition of user \"$safeusername\".\n" unless $noprint;
  152:     unlink('/tmp/lock_lcpasswd');
  153:     exit 12;
  154: }
  155: 
  156: # Make www a member of that user group.
  157: if (system('/usr/sbin/usermod','-G',$safeusername,'www')) {
  158:     print "Error. Could not make www a member of the group \"$safeusername\".\n" unless $noprint;
  159:     unlink('/tmp/lock_lcpasswd');
  160:     exit 6;
  161: }
  162: 
  163: # Set password with lcpasswd-style algorithm (which creates smbpasswd entry).
  164: # I cannot place a direct shell call to lcpasswd since I have to allow
  165: # for crazy characters in the password, and the setuid environment of perl
  166: # requires me to make everything safe.
  167: 
  168: # Grab the line corresponding to username
  169: open (IN, "</etc/passwd");
  170: @lines=<IN>;
  171: close IN;
  172: my ($userid,$useroldcryptpwd);
  173: my @F; my @U;
  174: for my $l (@lines) {
  175:     chop $l;
  176:     @F=split(/\:/,$l);
  177:     if ($F[0] eq $username) {($userid,$useroldcryptpwd)=($F[2],$F[1]); @U=@F;}
  178: }
  179: 
  180: # Verify existence of user
  181: if (!defined($userid)) {
  182:     print "Error. User $username does not exist.\n" unless $noprint;
  183:     unlink('/tmp/lock_lcpasswd');
  184:     exit 5;
  185: }
  186: 
  187: # Construct new password entry (random salt)
  188: my $newcryptpwd=crypt($password1,(join '', ('.', '/', 0..9, 'A'..'Z', 'a'..'z')[rand 64, rand 64]));
  189: $U[1]=$newcryptpwd;
  190: my $userline=join(':',@U);
  191: my $rootid=&enable_root_capability;
  192: if ($rootid!=0) {
  193:     print "Error.  Root was not successfully enabled.\n" unless $noprint;
  194:     unlink('/tmp/lock_lcpasswd');
  195:     exit 7;
  196: }
  197: open PASSWORDFILE, '>/etc/passwd' or (print("Error.  Cannot open /etc/passwd.\n") && unlink('/tmp/lock_lcpasswd') && exit(8));
  198: for my $l (@lines) {
  199:     @F=split(/\:/,$l);
  200:     if ($F[0] eq $username) {print PASSWORDFILE "$userline\n";}
  201:     else {print PASSWORDFILE "$l\n";}
  202: }
  203: close PASSWORDFILE;
  204: 
  205: ($>,$<)=(0,0); # fool smbpasswd here to think this is not a setuid environment
  206: unless (-e '/etc/smbpasswd') {
  207:     open (OUT,'>/etc/smbpasswd'); close OUT;
  208: }
  209: my $smbexist=0;
  210: open (IN, '</etc/smbpasswd');
  211: my @lines=<IN>;
  212: close IN;
  213: for my $l (@lines) {
  214:     chop $l;
  215:     my @F=split(/\:/,$l);
  216:     if ($F[0] eq $username) {$smbexist=1;}
  217: }
  218: unless ($smbexist) {
  219:     open(OUT,'>>/etc/smbpasswd');
  220:     print OUT join(':',($safeusername,$userid,'XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX:XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX','','/home/'.$safeusername,'/bin/bash')) . "\n";
  221:     close OUT;
  222: }
  223: open(OUT,"|/usr/bin/smbpasswd -s $safeusername>/dev/null");
  224: print OUT $password1; print OUT "\n";
  225: print OUT $password1; print OUT "\n";
  226: close OUT;
  227: $<=$wwwid; # unfool the program
  228: 
  229: # Make final modifications to the user directory.
  230: # Add a public_html file with a stand-in index.html file.
  231: 
  232: system('/bin/chmod','-R','0660',"/home/$safeusername");
  233: system('/bin/chmod','0770',"/home/$safeusername");
  234: mkdir "/home/$safeusername/public_html",0770;
  235: open OUT,">/home/$safeusername/public_html/index.html";
  236: print OUT<<END;
  237: <HTML>
  238: <HEAD>
  239: <TITLE>$safeusername</TITLE>
  240: </HEAD>
  241: <BODY>
  242: <H1>$safeusername</H1>
  243: <P>
  244: Learning Online Network
  245: </P>
  246: <P>
  247: This area provides for:
  248: </P>
  249: <UL>
  250: <LI>resource construction
  251: <LI>resource publication
  252: <LI>record-keeping
  253: </UL>
  254: </BODY>
  255: </HTML>
  256: END
  257: close OUT;
  258: system('/bin/chown','-R',"$safeusername:$safeusername","/home/$safeusername");
  259: &disable_root_capability;
  260: unlink('/tmp/lock_lcpasswd');
  261: exit 0;
  262: 
  263: # ----------------------------------------------------------- have setuid script run as root
  264: sub enable_root_capability {
  265:     if ($wwwid==$>) {
  266: 	($<,$>)=($>,$<);
  267: 	($(,$))=($),$();
  268:     }
  269:     else {
  270: 	# root capability is already enabled
  271:     }
  272:     return $>;
  273: }
  274: 
  275: # ----------------------------------------------------------- have setuid script run as www
  276: sub disable_root_capability {
  277:     if ($wwwid==$<) {
  278: 	($<,$>)=($>,$<);
  279: 	($(,$))=($),$();
  280:     }
  281:     else {
  282: 	# root capability is already disabled
  283:     }
  284: }
  285: 
  286: # ----------------------------------- make sure that another lcpasswd process isn't running
  287: sub try_to_lock {
  288:     my ($lockfile)=@_;
  289:     my $currentpid;
  290:     my $lastpid;
  291:     # Do not manipulate lock file as root
  292:     if ($>==0) {
  293: 	return 0;
  294:     }
  295:     # Try to generate lock file.
  296:     # Wait 3 seconds.  If same process id is in
  297:     # lock file, then assume lock file is stale, and
  298:     # go ahead.  If process id's fluctuate, try
  299:     # for a maximum of 10 times.
  300:     for (0..10) {
  301: 	if (-e $lockfile) {
  302: 	    open(LOCK,"<$lockfile");
  303: 	    $currentpid=<LOCK>;
  304: 	    close LOCK;
  305: 	    if ($currentpid==$lastpid) {
  306: 		last;
  307: 	    }
  308: 	    sleep 3;
  309: 	    $lastpid=$currentpid;
  310: 	}
  311: 	else {
  312: 	    last;
  313: 	}
  314: 	if ($_==10) {
  315: 	    return 0;
  316: 	}
  317:     }
  318:     open(LOCK,">$lockfile");
  319:     print LOCK $$;
  320:     close LOCK;
  321:     return 1;
  322: }