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 1.25.2.1 2004/08/05 21:01:20 albertel 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 $groups=`/usr/bin/groups www` or exit(6);
217: # untaint
218: my ($safegroups)=($groups=~/([\s\w]+)/);
219: $groups=$safegroups;
220: chomp $groups; $groups=~s/^\S+\s+\:\s+//;
221: my @grouplist=split(/\s+/,$groups);
222: my @ugrouplist=grep {!/www|$safeusername/} @grouplist;
223: my $gl=join(',',(@ugrouplist,$safeusername));
224: print "Putting user in its own group\n" unless $noprint;
225: if (system('/usr/sbin/usermod','-G',$gl,'www')) {
226: print "Error. Could not make www a member of the group ".
227: "\"$safeusername\".\n" unless $noprint;
228: unlink('/tmp/lock_lcpasswd');
229: exit 6;
230: }
231:
232: # ---------------------------------------------------------------- Set password
233: # Set password with lcpasswd (which creates smbpasswd entry).
234:
235: unlink('/tmp/lock_lcpasswd');
236: &disable_root_capability;
237: ($>,$<)=($wwwid,$wwwid);
238: print "Opening lcpasswd pipeline\n" unless $noprint;
239: open OUT,"|/home/httpd/perl/lcpasswd";
240: print OUT $safeusername;
241: print OUT "\n";
242: print OUT $password1;
243: print OUT "\n";
244: print OUT $password1;
245: print OUT "\n";
246: close OUT;
247: if ($?) {
248: print "abnormal exit from close lcpasswd\n" unless $noprint;
249: exit 8;
250: }
251: ($>,$<)=($wwwid,0);
252: &enable_root_capability;
253:
254: # -- Don't add public_html... that can be added either by the user
255: # or by lchtmldir when the user is granted an authorship role.
256:
257: # ------------------------------ Make final modifications to the user directory
258: # -- Add a public_html file with a stand-in index.html file
259:
260: system('/bin/chmod','-R','0660',"/home/$safeusername");
261: system('/bin/chmod','0710',"/home/$safeusername");
262: mkdir "/home/$safeusername/public_html",0755;
263: system('/bin/chmod','02770',"/home/$safeusername/public_html");
264: open OUT,">/home/$safeusername/public_html/index.html";
265: print OUT<<END;
266: <html>
267: <head>
268: <title>$safeusername</title>
269: </head>
270: <body>
271: <h1>Construction Space</h1>
272: <h3>$safeusername</h3>
273: </body>
274: </html>
275: END
276: close OUT;
277:
278: print "lcuseradd ownership\n" unless $noprint;
279: system('/bin/chown','-R',"$safeusername:$safeusername","/home/$safeusername");
280: # ---------------------------------------------------- Gracefull Apache Restart
281: if (-e '/var/run/httpd.pid') {
282: print "lcuseradd Apache restart\n" unless $noprint;
283: open(PID,'/var/run/httpd.pid');
284: my $pid=<PID>;
285: close(PID);
286: my ($safepid)=($pid=~s/(\D+)//g);
287: if ($pid) {
288: system('kill','-USR1',"$safepid");
289: }
290: }
291: # -------------------------------------------------------- Exit script
292: print "lcuseradd exiting\n" unless $noprint;
293: &disable_root_capability;
294: exit 0;
295:
296: # ---------------------------------------------- Have setuid script run as root
297: sub enable_root_capability {
298: if ($wwwid==$>) {
299: ($<,$>)=($>,0);
300: ($(,$))=($),0);
301: }
302: else {
303: # root capability is already enabled
304: }
305: return $>;
306: }
307:
308: # ----------------------------------------------- Have setuid script run as www
309: sub disable_root_capability {
310: if ($wwwid==$<) {
311: ($<,$>)=($>,$<);
312: ($(,$))=($),$();
313: }
314: else {
315: # root capability is already disabled
316: }
317: }
318:
319: # ----------------------- Make sure that another lcpasswd process isn't running
320: sub try_to_lock {
321: my ($lockfile)=@_;
322: my $currentpid;
323: my $lastpid;
324: # Do not manipulate lock file as root
325: if ($>==0) {
326: return 0;
327: }
328: # Try to generate lock file.
329: # Wait 3 seconds. If same process id is in
330: # lock file, then assume lock file is stale, and
331: # go ahead. If process id's fluctuate, try
332: # for a maximum of 10 times.
333: for (0..10) {
334: if (-e $lockfile) {
335: open(LOCK,"<$lockfile");
336: $currentpid=<LOCK>;
337: close LOCK;
338: if ($currentpid==$lastpid) {
339: last;
340: }
341: sleep 3;
342: $lastpid=$currentpid;
343: }
344: else {
345: last;
346: }
347: if ($_==10) {
348: return 0;
349: }
350: }
351: open(LOCK,">$lockfile");
352: print LOCK $$;
353: close LOCK;
354: return 1;
355: }
356:
357: =head1 NAME
358:
359: lcuseradd - LON-CAPA setuid script to coordinate all actions
360: with adding a user with filesystem privileges (e.g. author)
361:
362: =head1 DESCRIPTION
363:
364: lcuseradd - LON-CAPA setuid script to coordinate all actions
365: with adding a user with filesystem privileges (e.g. author)
366:
367: =head1 README
368:
369: lcuseradd - LON-CAPA setuid script to coordinate all actions
370: with adding a user with filesystem privileges (e.g. author)
371:
372: =head1 PREREQUISITES
373:
374: =head1 COREQUISITES
375:
376: =pod OSNAMES
377:
378: linux
379:
380: =pod SCRIPT CATEGORIES
381:
382: LONCAPA/Administrative
383:
384: =cut
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