Annotation of loncom/lcuseradd, revision 1.22

1.1       harris41    1: #!/usr/bin/perl
1.16      harris41    2: 
                      3: # The Learning Online Network with CAPA
1.1       harris41    4: #
1.16      harris41    5: # lcuseradd - LON-CAPA setuid script to coordinate all actions
                      6: #             with adding a user with filesystem privileges (e.g. author)
1.1       harris41    7: #
1.16      harris41    8: # YEAR=2000
                      9: # 10/27,10/29,10/30 Scott Harrison
1.15      harris41   10: # YEAR=2001
1.16      harris41   11: # 10/21,11/13,11/15 Scott Harrison
1.20      foxr       12: # YEAR=2002
                     13: #   May 19, 2002 Ron Fox
                     14: #      - Removed creation of the pulic_html directory.  This directory
                     15: #        can now be added in two ways:
                     16: #        o The user can add it themselves if they want some local web
                     17: #          space which may or may not contain construction items.
                     18: #        o LonCapa will add it if/when the user is granted an Author
                     19: #          role.
1.16      harris41   20: #
1.22    ! foxr       21: # $Id: lcuseradd,v 1.21 2002/05/03 03:43:54 foxr Exp $
1.16      harris41   22: ###
1.15      harris41   23: 
                     24: ###############################################################################
                     25: ##                                                                           ##
                     26: ## ORGANIZATION OF THIS PERL SCRIPT                                          ##
                     27: ##                                                                           ##
                     28: ## 1. Description of script                                                  ##
                     29: ## 2. Invoking script (standard input)                                       ##
                     30: ## 3. Example usage inside another piece of code                             ##
                     31: ## 4. Description of functions                                               ##
                     32: ## 5. Exit codes                                                             ##
                     33: ## 6. Initializations                                                        ##
                     34: ## 7. Make sure this process is running from user=www                        ##
                     35: ## 8. Start running script with www permissions                              ##
                     36: ## 9. Handle case of another lcpasswd process (locking)                      ##
                     37: ## 10. Error-check input, need 3 values (user name, password 1, password 2)  ##
                     38: ## 11. Start running script with root permissions                            ##
                     39: ## 12. Add user and make www a member of the user-specific group             ##
                     40: ## 13. Set password                                                          ##
                     41: ## 14. Make final modifications to the user directory                        ##
                     42: ## 15. Exit script (unlock)                                                  ##
                     43: ##                                                                           ##
                     44: ###############################################################################
1.1       harris41   45: 
                     46: use strict;
                     47: 
1.15      harris41   48: # ------------------------------------------------------- Description of script
                     49: #
1.1       harris41   50: # This script is a setuid script that should
1.20      foxr       51: # be run by user 'www'.  It creates a /home/USERNAME directory.
1.15      harris41   52: # It adds a user to the unix system.
1.2       harris41   53: # Passwords are set with lcpasswd.
                     54: # www becomes a member of this user group.
1.1       harris41   55: 
1.15      harris41   56: # -------------- Invoking script (standard input versus command-line arguments)
                     57: #
                     58: # Standard input (STDIN) usage
1.1       harris41   59: # First line is USERNAME
                     60: # Second line is PASSWORD
1.3       harris41   61: # Third line is PASSWORD
1.15      harris41   62: #
                     63: # Command-line arguments [USERNAME] [PASSWORD] [PASSWORD]
                     64: # Yes, but be very careful here (don't pass shell commands)
                     65: # and this is only supported to allow perl-system calls.
                     66: #
1.7       harris41   67: # Valid passwords must consist of the
                     68: # ascii characters within the inclusive
                     69: # range of 0x20 (32) to 0x7E (126).
                     70: # These characters are:
                     71: # SPACE and
                     72: # !"#$%&'()*+,-./0123456789:;<=>?@ABCDEFGHIJKLMNO
                     73: # PQRSTUVWXYZ[\]^_`abcdefghijklmnopqrstuvwxyz{|}~
1.15      harris41   74: #
1.7       harris41   75: # Valid user names must consist of ascii
                     76: # characters that are alphabetical characters
                     77: # (A-Z,a-z), numeric (0-9), or the underscore
                     78: # mark (_). (Essentially, the perl regex \w).
1.15      harris41   79: # User names must begin with an alphabetical character
                     80: # (A-Z,a-z).
1.7       harris41   81: 
1.15      harris41   82: # ---------------------------------- Example usage inside another piece of code
1.4       harris41   83: # Usage within code
                     84: #
1.15      harris41   85: # $exitcode=
                     86: #      system("/home/httpd/perl/lcuseradd","NAME","PASSWORD1","PASSWORD2")/256;
1.4       harris41   87: # print "uh-oh" if $exitcode;
                     88: 
1.15      harris41   89: # ---------------------------------------------------- Description of functions
                     90: # enable_root_capability() : have setuid script run as root
                     91: # disable_root_capability() : have setuid script run as www
                     92: # try_to_lock() : make sure that another lcpasswd process isn't running
                     93: 
                     94: # ------------------------------------------------------------------ Exit codes
1.4       harris41   95: # These are the exit codes.
1.13      harris41   96: # ( (0,"ok"),
                     97: # (1,"User ID mismatch.  This program must be run as user 'www'"),
1.15      harris41   98: # (2,"Error. This program needs 3 command-line arguments (username, ".
                     99: #    "password 1, password 2)."),
1.13      harris41  100: # (3,"Error. Three lines should be entered into standard input."),
1.15      harris41  101: # (4,"Error. Too many other simultaneous password change requests being ".
                    102: #    "made."),
1.13      harris41  103: # (5,"Error. User $username does not exist."),
                    104: # (6,"Error. Could not make www a member of the group \"$safeusername\"."),
                    105: # (7,"Error. Root was not successfully enabled.),
1.15      harris41  106: # (8,"Error. Cannot set password."),
1.13      harris41  107: # (9,"Error. The user name specified has invalid characters."),
                    108: # (10,"Error. A password entry had an invalid character."),
                    109: # (11,"Error. User already exists.),
1.15      harris41  110: # (12,"Error. Something went wrong with the addition of user ".
                    111: #     "\"$safeusername\"."),
1.13      harris41  112: # (13,"Error. Password mismatch."),
1.4       harris41  113: 
1.15      harris41  114: # ------------------------------------------------------------- Initializations
1.1       harris41  115: # Security
1.15      harris41  116: $ENV{'PATH'}='/bin/:/usr/bin:/usr/local/sbin:/home/httpd/perl'; # Nullify path
                    117:                                                                 # information
1.16      harris41  118: delete @ENV{qw(IFS CDPATH ENV BASH_ENV)}; # nullify potential taints
1.2       harris41  119: 
1.15      harris41  120: # Do not print error messages.
                    121: my $noprint=1;
                    122: 
                    123: # ----------------------------- Make sure this process is running from user=www
                    124: my $wwwid=getpwnam('www');
                    125: &disable_root_capability;
                    126: if ($wwwid!=$>) {
                    127:     print("User ID mismatch.  This program must be run as user 'www'\n")
                    128: 	unless $noprint;
1.4       harris41  129:     exit 1;
                    130: }
1.15      harris41  131: 
                    132: # ----------------------------------- Start running script with www permissions
1.4       harris41  133: &disable_root_capability;
                    134: 
1.15      harris41  135: # --------------------------- Handle case of another lcpasswd process (locking)
1.4       harris41  136: unless (&try_to_lock("/tmp/lock_lcpasswd")) {
1.15      harris41  137:     print "Error. Too many other simultaneous password change requests being ".
                    138: 	"made.\n" unless $noprint;
1.4       harris41  139:     exit 4;
                    140: }
                    141: 
1.15      harris41  142: # ------- Error-check input, need 3 values (user name, password 1, password 2).
1.4       harris41  143: my @input;
1.5       harris41  144: if (@ARGV==3) {
1.4       harris41  145:     @input=@ARGV;
                    146: }
                    147: elsif (@ARGV) {
1.15      harris41  148:     print("Error. This program needs 3 command-line arguments (username, ".
                    149: 	  "password 1, password 2).\n") unless $noprint;
1.4       harris41  150:     unlink('/tmp/lock_lcpasswd');
                    151:     exit 2;
                    152: }
                    153: else {
                    154:     @input=<>;
1.5       harris41  155:     if (@input!=3) {
1.15      harris41  156: 	print("Error. Three lines should be entered into standard input.\n")
                    157: 	    unless $noprint;
1.4       harris41  158: 	unlink('/tmp/lock_lcpasswd');
                    159: 	exit 3;
                    160:     }
1.19      harris41  161:     foreach (@input) {chomp;}
1.4       harris41  162: }
                    163: 
                    164: my ($username,$password1,$password2)=@input;
1.22    ! foxr      165: print "Username = ".$username unless $noprint;
1.4       harris41  166: $username=~/^(\w+)$/;
1.22    ! foxr      167: print "Username after substitution - ".$username unless $noprint;
1.4       harris41  168: my $safeusername=$1;
1.22    ! foxr      169: print "Safe username = $safeusername" unless $noprint;
        !           170: 
1.15      harris41  171: if (($username ne $safeusername) or ($safeusername!~/^[A-Za-z]/)) {
1.22    ! foxr      172:     print "Error. The user name specified $username $safeusername  has invalid characters.\n"
1.15      harris41  173: 	unless $noprint;
1.8       harris41  174:     unlink('/tmp/lock_lcpasswd');
                    175:     exit 9;
                    176: }
                    177: my $pbad=0;
1.19      harris41  178: foreach (split(//,$password1)) {if ((ord($_)<32)||(ord($_)>126)){$pbad=1;}}
                    179: foreach (split(//,$password2)) {if ((ord($_)<32)||(ord($_)>126)){$pbad=1;}}
1.8       harris41  180: if ($pbad) {
                    181:     print "Error. A password entry had an invalid character.\n";
                    182:     unlink('/tmp/lock_lcpasswd');
                    183:     exit 10;
                    184: }
1.5       harris41  185: 
1.15      harris41  186: # -- Only add user if we can create a brand new home directory (/home/username)
1.7       harris41  187: if (-e "/home/$safeusername") {
                    188:     print "Error. User already exists.\n" unless $noprint;
                    189:     unlink('/tmp/lock_lcpasswd');
1.13      harris41  190:     exit 11;
1.7       harris41  191: }
                    192: 
1.15      harris41  193: # -- Only add user if the two password arguments match.
1.5       harris41  194: if ($password1 ne $password2) {
1.6       harris41  195:     print "Error. Password mismatch.\n" unless $noprint;
1.5       harris41  196:     unlink('/tmp/lock_lcpasswd');
1.13      harris41  197:     exit 13;
1.5       harris41  198: }
1.4       harris41  199: 
1.15      harris41  200: # ---------------------------------- Start running script with root permissions
1.4       harris41  201: &enable_root_capability;
                    202: 
1.15      harris41  203: # ------------------- Add user and make www a member of the user-specific group
                    204: # -- Add user
1.5       harris41  205: if (system('/usr/sbin/useradd','-c','LON-CAPA user',$safeusername)) {
1.15      harris41  206:     print "Error.  Something went wrong with the addition of user ".
                    207: 	  "\"$safeusername\".\n" unless $noprint;
1.4       harris41  208:     unlink('/tmp/lock_lcpasswd');
1.13      harris41  209:     exit 12;
1.4       harris41  210: }
1.7       harris41  211: 
                    212: # Make www a member of that user group.
1.17      harris41  213: my $groups=`/usr/bin/groups www` or exit(6);
                    214: chomp $groups; $groups=~s/^\S+\s+\:\s+//;
                    215: my @grouplist=split(/\s+/,$groups);
                    216: my @ugrouplist=grep {!/www|$safeusername/} @grouplist;
                    217: my $gl=join(',',(@ugrouplist,$safeusername));
                    218: if (system('/usr/sbin/usermod','-G',$gl,'www')) {
1.15      harris41  219:     print "Error. Could not make www a member of the group ".
                    220: 	  "\"$safeusername\".\n" unless $noprint;
1.5       harris41  221:     unlink('/tmp/lock_lcpasswd');
                    222:     exit 6;
                    223: }
                    224: 
1.15      harris41  225: # ---------------------------------------------------------------- Set password
                    226: # Set password with lcpasswd (which creates smbpasswd entry).
1.2       harris41  227: 
1.15      harris41  228: unlink('/tmp/lock_lcpasswd');
                    229: &disable_root_capability;
1.16      harris41  230: ($>,$<)=($wwwid,$wwwid);
                    231: open OUT,"|/home/httpd/perl/lcpasswd";
1.15      harris41  232: print OUT $safeusername;
                    233: print OUT "\n";
                    234: print OUT $password1;
                    235: print OUT "\n";
                    236: print OUT $password1;
                    237: print OUT "\n";
                    238: close OUT;
                    239: if ($?) {
                    240:     exit 8;
1.8       harris41  241: }
1.18      harris41  242: ($>,$<)=($wwwid,0);
1.15      harris41  243: &enable_root_capability;
1.8       harris41  244: 
1.20      foxr      245: # -- Don't add public_html... that can be added either by the user
                    246: #    or by lchtmldir when the user is granted an authorship role.
                    247: 
1.15      harris41  248: # ------------------------------ Make final modifications to the user directory
                    249: # -- Add a public_html file with a stand-in index.html file
1.8       harris41  250: 
1.21      foxr      251:  system('/bin/chmod','-R','0660',"/home/$safeusername");
                    252: system('/bin/chmod','0710',"/home/$safeusername");
                    253: mkdir "/home/$safeusername/public_html",0755;
                    254: system('/bin/chmod','02770',"/home/$safeusername/public_html");
                    255: open OUT,">/home/$safeusername/public_html/index.html";
                    256: print OUT<<END;
                    257: <html>
                    258: <head>
                    259: <title>$safeusername</title>
                    260: </head>
                    261: <body>
                    262: <h1>$safeusername</h1>
                    263: <p>
                    264: Learning Online Network
                    265: </p>
                    266: <p>
                    267: This area provides for:
                    268: </p>
                    269: <ul>
                    270: <li>resource construction</li>
                    271: <li>resource publication</li>
                    272: <li>record-keeping</li>
                    273: </ul>
                    274: </body>
                    275: </html>
                    276: END
                    277: close OUT;
1.20      foxr      278: 
1.11      harris41  279: system('/bin/chown','-R',"$safeusername:$safeusername","/home/$safeusername");
1.15      harris41  280: 
                    281: # -------------------------------------------------------- Exit script
1.8       harris41  282: &disable_root_capability;
                    283: exit 0;
1.1       harris41  284: 
1.15      harris41  285: # ---------------------------------------------- Have setuid script run as root
1.5       harris41  286: sub enable_root_capability {
                    287:     if ($wwwid==$>) {
                    288: 	($<,$>)=($>,$<);
                    289: 	($(,$))=($),$();
                    290:     }
                    291:     else {
                    292: 	# root capability is already enabled
                    293:     }
                    294:     return $>;
                    295: }
                    296: 
1.15      harris41  297: # ----------------------------------------------- Have setuid script run as www
1.5       harris41  298: sub disable_root_capability {
                    299:     if ($wwwid==$<) {
                    300: 	($<,$>)=($>,$<);
                    301: 	($(,$))=($),$();
                    302:     }
                    303:     else {
                    304: 	# root capability is already disabled
                    305:     }
                    306: }
                    307: 
1.15      harris41  308: # ----------------------- Make sure that another lcpasswd process isn't running
1.5       harris41  309: sub try_to_lock {
                    310:     my ($lockfile)=@_;
                    311:     my $currentpid;
                    312:     my $lastpid;
                    313:     # Do not manipulate lock file as root
                    314:     if ($>==0) {
                    315: 	return 0;
                    316:     }
                    317:     # Try to generate lock file.
                    318:     # Wait 3 seconds.  If same process id is in
                    319:     # lock file, then assume lock file is stale, and
                    320:     # go ahead.  If process id's fluctuate, try
                    321:     # for a maximum of 10 times.
                    322:     for (0..10) {
                    323: 	if (-e $lockfile) {
                    324: 	    open(LOCK,"<$lockfile");
                    325: 	    $currentpid=<LOCK>;
                    326: 	    close LOCK;
                    327: 	    if ($currentpid==$lastpid) {
                    328: 		last;
                    329: 	    }
                    330: 	    sleep 3;
                    331: 	    $lastpid=$currentpid;
                    332: 	}
                    333: 	else {
                    334: 	    last;
                    335: 	}
                    336: 	if ($_==10) {
                    337: 	    return 0;
                    338: 	}
                    339:     }
                    340:     open(LOCK,">$lockfile");
                    341:     print LOCK $$;
                    342:     close LOCK;
                    343:     return 1;
                    344: }
1.16      harris41  345: 
                    346: =head1 NAME
                    347: 
                    348: lcuseradd - LON-CAPA setuid script to coordinate all actions
                    349:             with adding a user with filesystem privileges (e.g. author)
                    350: 
                    351: =head1 DESCRIPTION
                    352: 
                    353: lcuseradd - LON-CAPA setuid script to coordinate all actions
                    354:             with adding a user with filesystem privileges (e.g. author)
                    355: 
                    356: =head1 README
                    357: 
                    358: lcuseradd - LON-CAPA setuid script to coordinate all actions
                    359:             with adding a user with filesystem privileges (e.g. author)
                    360: 
                    361: =head1 PREREQUISITES
                    362: 
                    363: =head1 COREQUISITES
                    364: 
                    365: =pod OSNAMES
                    366: 
                    367: linux
                    368: 
                    369: =pod SCRIPT CATEGORIES
                    370: 
                    371: LONCAPA/Administrative
                    372: 
                    373: =cut

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