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