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best wishes to all.

    1: #!/usr/bin/perl
    2: 
    3: # The Learning Online Network with CAPA
    4: #
    5: # lcuseradd - LON-CAPA setuid script to coordinate all actions
    6: #             with adding a user with filesystem privileges (e.g. author)
    7: #
    8: # YEAR=2002
    9: #   May 19, 2002 Ron Fox
   10: #      - Removed creation of the pulic_html directory.  This directory
   11: #        can now be added in two ways:
   12: #        o The user can add it themselves if they want some local web
   13: #          space which may or may not contain construction items.
   14: #        o LonCapa will add it if/when the user is granted an Author
   15: #          role.
   16: #
   17: # $Id: lcuseradd,v 1.25 2003/02/03 18:03:52 harris41 Exp $
   18: ###
   19: 
   20: ###############################################################################
   21: ##                                                                           ##
   22: ## ORGANIZATION OF THIS PERL SCRIPT                                          ##
   23: ##                                                                           ##
   24: ## 1. Description of script                                                  ##
   25: ## 2. Invoking script (standard input)                                       ##
   26: ## 3. Example usage inside another piece of code                             ##
   27: ## 4. Description of functions                                               ##
   28: ## 5. Exit codes                                                             ##
   29: ## 6. Initializations                                                        ##
   30: ## 7. Make sure this process is running from user=www                        ##
   31: ## 8. Start running script with www permissions                              ##
   32: ## 9. Handle case of another lcpasswd process (locking)                      ##
   33: ## 10. Error-check input, need 3 values (user name, password 1, password 2)  ##
   34: ## 11. Start running script with root permissions                            ##
   35: ## 12. Add user and make www a member of the user-specific group             ##
   36: ## 13. Set password                                                          ##
   37: ## 14. Make final modifications to the user directory                        ##
   38: ## 15. Exit script (unlock)                                                  ##
   39: ##                                                                           ##
   40: ###############################################################################
   41: 
   42: use strict;
   43: 
   44: # ------------------------------------------------------- Description of script
   45: #
   46: # This script is a setuid script that should
   47: # be run by user 'www'.  It creates a /home/USERNAME directory.
   48: # It adds a user to the unix system.
   49: # Passwords are set with lcpasswd.
   50: # www becomes a member of this user group.
   51: 
   52: # -------------- Invoking script (standard input versus command-line arguments)
   53: #
   54: # Standard input (STDIN) usage
   55: # First line is USERNAME
   56: # Second line is PASSWORD
   57: # Third line is PASSWORD
   58: #
   59: # Command-line arguments [USERNAME] [PASSWORD] [PASSWORD]
   60: # Yes, but be very careful here (don't pass shell commands)
   61: # and this is only supported to allow perl-system calls.
   62: #
   63: # Valid passwords must consist of the
   64: # ascii characters within the inclusive
   65: # range of 0x20 (32) to 0x7E (126).
   66: # These characters are:
   67: # SPACE and
   68: # !"#$%&'()*+,-./0123456789:;<=>?@ABCDEFGHIJKLMNO
   69: # PQRSTUVWXYZ[\]^_`abcdefghijklmnopqrstuvwxyz{|}~
   70: #
   71: # Valid user names must consist of ascii
   72: # characters that are alphabetical characters
   73: # (A-Z,a-z), numeric (0-9), or the underscore
   74: # mark (_). (Essentially, the perl regex \w).
   75: # User names must begin with an alphabetical character
   76: # (A-Z,a-z).
   77: 
   78: # ---------------------------------- Example usage inside another piece of code
   79: # Usage within code
   80: #
   81: # $exitcode=
   82: #      system("/home/httpd/perl/lcuseradd","NAME","PASSWORD1","PASSWORD2")/256;
   83: # print "uh-oh" if $exitcode;
   84: 
   85: # ---------------------------------------------------- Description of functions
   86: # enable_root_capability() : have setuid script run as root
   87: # disable_root_capability() : have setuid script run as www
   88: # try_to_lock() : make sure that another lcpasswd process isn't running
   89: 
   90: # ------------------------------------------------------------------ Exit codes
   91: # These are the exit codes.
   92: # ( (0,"ok"),
   93: # (1,"User ID mismatch.  This program must be run as user 'www'"),
   94: # (2,"Error. This program needs 3 command-line arguments (username, ".
   95: #    "password 1, password 2)."),
   96: # (3,"Error. Three lines should be entered into standard input."),
   97: # (4,"Error. Too many other simultaneous password change requests being ".
   98: #    "made."),
   99: # (5,"Error. User $username does not exist."),
  100: # (6,"Error. Could not make www a member of the group \"$safeusername\"."),
  101: # (7,"Error. Root was not successfully enabled.),
  102: # (8,"Error. Cannot set password."),
  103: # (9,"Error. The user name specified has invalid characters."),
  104: # (10,"Error. A password entry had an invalid character."),
  105: # (11,"Error. User already exists.),
  106: # (12,"Error. Something went wrong with the addition of user ".
  107: #     "\"$safeusername\"."),
  108: # (13,"Error. Password mismatch."),
  109: 
  110: # ------------------------------------------------------------- Initializations
  111: # Security
  112: $ENV{'PATH'}='/bin/:/usr/bin:/usr/local/sbin:/home/httpd/perl'; # Nullify path
  113:                                                                 # information
  114: delete @ENV{qw(IFS CDPATH ENV BASH_ENV)}; # nullify potential taints
  115: 
  116: # Do not print error messages.
  117: my $noprint=1;
  118: 
  119: print "In lcuseradd\n" unless $noprint;
  120: 
  121: # ----------------------------- Make sure this process is running from user=www
  122: my $wwwid=getpwnam('www');
  123: &disable_root_capability;
  124: if ($wwwid!=$>) {
  125:     print("User ID mismatch.  This program must be run as user 'www'\n")
  126: 	unless $noprint;
  127:     exit 1;
  128: }
  129: 
  130: # ----------------------------------- Start running script with www permissions
  131: &disable_root_capability;
  132: 
  133: # --------------------------- Handle case of another lcpasswd process (locking)
  134: unless (&try_to_lock("/tmp/lock_lcpasswd")) {
  135:     print "Error. Too many other simultaneous password change requests being ".
  136: 	"made.\n" unless $noprint;
  137:     exit 4;
  138: }
  139: 
  140: # ------- Error-check input, need 3 values (user name, password 1, password 2).
  141: my @input;
  142: if (@ARGV==3) {
  143:     @input=@ARGV;
  144: }
  145: elsif (@ARGV) {
  146:     print("Error. This program needs 3 command-line arguments (username, ".
  147: 	  "password 1, password 2).\n") unless $noprint;
  148:     unlink('/tmp/lock_lcpasswd');
  149:     exit 2;
  150: }
  151: else {
  152:     @input=<>;
  153:     if (@input!=3) {
  154: 	print("Error. Three lines should be entered into standard input.\n")
  155: 	    unless $noprint;
  156: 	unlink('/tmp/lock_lcpasswd');
  157: 	exit 3;
  158:     }
  159:     foreach (@input) {chomp;}
  160: }
  161: 
  162: my ($username,$password1,$password2)=@input;
  163: print "Username = ".$username."\n" unless $noprint;
  164: $username=~/^(\w+)$/;
  165: print "Username after substitution - ".$username unless $noprint;
  166: my $safeusername=$1;
  167: print "Safe username = $safeusername \n" unless $noprint;
  168: 
  169: if (($username ne $safeusername) or ($safeusername!~/^[A-Za-z]/)) {
  170:     print "Error. The user name specified $username $safeusername  has invalid characters.\n"
  171: 	unless $noprint;
  172:     unlink('/tmp/lock_lcpasswd');
  173:     exit 9;
  174: }
  175: my $pbad=0;
  176: foreach (split(//,$password1)) {if ((ord($_)<32)||(ord($_)>126)){$pbad=1;}}
  177: foreach (split(//,$password2)) {if ((ord($_)<32)||(ord($_)>126)){$pbad=1;}}
  178: if ($pbad) {
  179:     print "Error. A password entry had an invalid character.\n";
  180:     unlink('/tmp/lock_lcpasswd');
  181:     exit 10;
  182: }
  183: 
  184: # -- Only add user if we can create a brand new home directory (/home/username)
  185: if (-e "/home/$safeusername") {
  186:     print "Error. User already exists.\n" unless $noprint;
  187:     unlink('/tmp/lock_lcpasswd');
  188:     exit 11;
  189: }
  190: 
  191: # -- Only add user if the two password arguments match.
  192: 
  193: if ($password1 ne $password2) {
  194:     print "Error. Password mismatch.\n" unless $noprint;
  195:     unlink('/tmp/lock_lcpasswd');
  196:     exit 13;
  197: }
  198: print "enabling root\n" unless $noprint;
  199: # ---------------------------------- Start running script with root permissions
  200: &enable_root_capability;
  201: 
  202: # ------------------- Add user and make www a member of the user-specific group
  203: # -- Add user
  204: 
  205: print "adding user: $safeusername \n" unless $noprint;
  206: my $status = system('/usr/sbin/useradd','-c','LON-CAPA user',$safeusername);
  207: if ($status) {
  208:     print "Error.  Something went wrong with the addition of user ".
  209: 	  "\"$safeusername\".\n" unless $noprint;
  210:     print "Final status of useradd = $status";
  211:     unlink('/tmp/lock_lcpasswd');
  212:     exit 12;
  213: }
  214: print "Done adding user\n" unless $noprint;
  215: # Make www a member of that user group.
  216: my $groups=`/usr/bin/groups www` or exit(6);
  217: chomp $groups; $groups=~s/^\S+\s+\:\s+//;
  218: my @grouplist=split(/\s+/,$groups);
  219: my @ugrouplist=grep {!/www|$safeusername/} @grouplist;
  220: my $gl=join(',',(@ugrouplist,$safeusername));
  221: print "Putting user in its own group\n" unless $noprint;
  222: if (system('/usr/sbin/usermod','-G',$gl,'www')) {
  223:     print "Error. Could not make www a member of the group ".
  224: 	  "\"$safeusername\".\n" unless $noprint;
  225:     unlink('/tmp/lock_lcpasswd');
  226:     exit 6;
  227: }
  228: 
  229: # ---------------------------------------------------------------- Set password
  230: # Set password with lcpasswd (which creates smbpasswd entry).
  231: 
  232: unlink('/tmp/lock_lcpasswd');
  233: &disable_root_capability;
  234: ($>,$<)=($wwwid,$wwwid);
  235: print "Opening lcpasswd pipeline\n" unless $noprint;
  236: open OUT,"|/home/httpd/perl/lcpasswd";
  237: print OUT $safeusername;
  238: print OUT "\n";
  239: print OUT $password1;
  240: print OUT "\n";
  241: print OUT $password1;
  242: print OUT "\n";
  243: close OUT;
  244: if ($?) {
  245:     print "abnormal exit from close lcpasswd\n" unless $noprint;
  246:     exit 8;
  247: }
  248: ($>,$<)=($wwwid,0);
  249: &enable_root_capability;
  250: 
  251: # -- Don't add public_html... that can be added either by the user
  252: #    or by lchtmldir when the user is granted an authorship role.
  253: 
  254: # ------------------------------ Make final modifications to the user directory
  255: # -- Add a public_html file with a stand-in index.html file
  256: 
  257:  system('/bin/chmod','-R','0660',"/home/$safeusername");
  258: system('/bin/chmod','0710',"/home/$safeusername");
  259: mkdir "/home/$safeusername/public_html",0755;
  260: system('/bin/chmod','02770',"/home/$safeusername/public_html");
  261: open OUT,">/home/$safeusername/public_html/index.html";
  262: print OUT<<END;
  263: <html>
  264: <head>
  265: <title>$safeusername</title>
  266: </head>
  267: <body>
  268: <h1>Construction Space</h1>
  269: <h3>$safeusername</h3>
  270: </body>
  271: </html>
  272: END
  273: close OUT;
  274: 
  275: print "lcuseradd ownership\n" unless $noprint;
  276: system('/bin/chown','-R',"$safeusername:$safeusername","/home/$safeusername");
  277: # ---------------------------------------------------- Gracefull Apache Restart
  278: if (-e '/var/run/httpd.pid') {
  279:     print "lcuseradd Apache restart\n" unless $noprint;
  280:     open(PID,'/var/run/httpd.pid');
  281:     my $pid=<PID>;
  282:     close(PID);
  283:     $pid=~s/\D+//g;
  284:     if ($pid) {
  285: 	system('kill','-USR1',"$pid");
  286:     }
  287: }
  288: # -------------------------------------------------------- Exit script
  289: print "lcuseradd exiting\n" unless $noprint;
  290: &disable_root_capability;
  291: exit 0;
  292: 
  293: # ---------------------------------------------- Have setuid script run as root
  294: sub enable_root_capability {
  295:     if ($wwwid==$>) {
  296: 	($<,$>)=($>,0);
  297: 	($(,$))=($),0);
  298:     }
  299:     else {
  300: 	# root capability is already enabled
  301:     }
  302:     return $>;
  303: }
  304: 
  305: # ----------------------------------------------- Have setuid script run as www
  306: sub disable_root_capability {
  307:     if ($wwwid==$<) {
  308: 	($<,$>)=($>,$<);
  309: 	($(,$))=($),$();
  310:     }
  311:     else {
  312: 	# root capability is already disabled
  313:     }
  314: }
  315: 
  316: # ----------------------- Make sure that another lcpasswd process isn't running
  317: sub try_to_lock {
  318:     my ($lockfile)=@_;
  319:     my $currentpid;
  320:     my $lastpid;
  321:     # Do not manipulate lock file as root
  322:     if ($>==0) {
  323: 	return 0;
  324:     }
  325:     # Try to generate lock file.
  326:     # Wait 3 seconds.  If same process id is in
  327:     # lock file, then assume lock file is stale, and
  328:     # go ahead.  If process id's fluctuate, try
  329:     # for a maximum of 10 times.
  330:     for (0..10) {
  331: 	if (-e $lockfile) {
  332: 	    open(LOCK,"<$lockfile");
  333: 	    $currentpid=<LOCK>;
  334: 	    close LOCK;
  335: 	    if ($currentpid==$lastpid) {
  336: 		last;
  337: 	    }
  338: 	    sleep 3;
  339: 	    $lastpid=$currentpid;
  340: 	}
  341: 	else {
  342: 	    last;
  343: 	}
  344: 	if ($_==10) {
  345: 	    return 0;
  346: 	}
  347:     }
  348:     open(LOCK,">$lockfile");
  349:     print LOCK $$;
  350:     close LOCK;
  351:     return 1;
  352: }
  353: 
  354: =head1 NAME
  355: 
  356: lcuseradd - LON-CAPA setuid script to coordinate all actions
  357:             with adding a user with filesystem privileges (e.g. author)
  358: 
  359: =head1 DESCRIPTION
  360: 
  361: lcuseradd - LON-CAPA setuid script to coordinate all actions
  362:             with adding a user with filesystem privileges (e.g. author)
  363: 
  364: =head1 README
  365: 
  366: lcuseradd - LON-CAPA setuid script to coordinate all actions
  367:             with adding a user with filesystem privileges (e.g. author)
  368: 
  369: =head1 PREREQUISITES
  370: 
  371: =head1 COREQUISITES
  372: 
  373: =pod OSNAMES
  374: 
  375: linux
  376: 
  377: =pod SCRIPT CATEGORIES
  378: 
  379: LONCAPA/Administrative
  380: 
  381: =cut