Annotation of loncom/lcuseradd, revision 1.13
1.1 harris41 1: #!/usr/bin/perl
2: #
3: # lcuseradd
4: #
5: # Scott Harrison
1.13 ! harris41 6: # SH: October 27, 2000
! 7: # SH: October 29, 2000
1.1 harris41 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.
1.2 harris41 16: # Passwords are set with lcpasswd.
17: # www becomes a member of this user group.
1.1 harris41 18:
19: # Standard input usage
20: # First line is USERNAME
21: # Second line is PASSWORD
1.3 harris41 22: # Third line is PASSWORD
1.1 harris41 23:
1.7 harris41 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:
1.3 harris41 37: # Command-line arguments [USERNAME] [PASSWORD] [PASSWORD]
1.1 harris41 38: # Yes, but be very careful here (don't pass shell commands)
39: # and this is only supported to allow perl-system calls.
40:
1.4 harris41 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.
1.13 ! harris41 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."),
1.4 harris41 61:
1.1 harris41 62: # Security
63: $ENV{'PATH'}=""; # Nullify path information.
64: $ENV{'BASH_ENV'}=""; # Nullify shell environment information.
1.2 harris41 65:
1.4 harris41 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;
1.5 harris41 96: if (@ARGV==3) {
1.4 harris41 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=<>;
1.5 harris41 106: if (@input!=3) {
1.4 harris41 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=$1;
1.8 harris41 117: if ($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 $pbad=0;
1.9 harris41 123: map {if ((ord($_)<32)||(ord($_)>126)){$pbad=1;}} (split(//,$password1));
124: map {if ((ord($_)<32)||(ord($_)>126)){$pbad=1;}} (split(//,$password2));
1.8 harris41 125: if ($pbad) {
126: print "Error. A password entry had an invalid character.\n";
127: unlink('/tmp/lock_lcpasswd');
128: exit 10;
129: }
1.5 harris41 130:
1.7 harris41 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 $noprint;
134: unlink('/tmp/lock_lcpasswd');
1.13 ! harris41 135: exit 11;
1.7 harris41 136: }
137:
138: # Only add user if the two password arguments match.
1.5 harris41 139: if ($password1 ne $password2) {
1.6 harris41 140: print "Error. Password mismatch.\n" unless $noprint;
1.5 harris41 141: unlink('/tmp/lock_lcpasswd');
1.13 ! harris41 142: exit 13;
1.5 harris41 143: }
1.4 harris41 144:
145: &enable_root_capability;
146:
1.3 harris41 147: # Add user entry to /etc/passwd and /etc/groups in such
148: # a way that www is a member of the user-specific group
149:
1.5 harris41 150: if (system('/usr/sbin/useradd','-c','LON-CAPA user',$safeusername)) {
1.6 harris41 151: print "Error. Something went wrong with the addition of user \"$safeusername\".\n" unless $noprint;
1.4 harris41 152: unlink('/tmp/lock_lcpasswd');
1.13 ! harris41 153: exit 12;
1.4 harris41 154: }
1.7 harris41 155:
156: # Make www a member of that user group.
1.5 harris41 157: if (system('/usr/sbin/usermod','-G',$safeusername,'www')) {
1.6 harris41 158: print "Error. Could not make www a member of the group \"$safeusername\".\n" unless $noprint;
1.5 harris41 159: unlink('/tmp/lock_lcpasswd');
160: exit 6;
161: }
162:
163: # Set password with lcpasswd-style algorithm (which creates smbpasswd entry).
164: # I cannot place a direct shell call to lcpasswd since I have to allow
165: # for crazy characters in the password, and the setuid environment of perl
166: # requires me to make everything safe.
1.7 harris41 167:
1.8 harris41 168: # Grab the line corresponding to username
1.9 harris41 169: open (IN, "</etc/passwd");
170: @lines=<IN>;
171: close IN;
1.8 harris41 172: my ($userid,$useroldcryptpwd);
173: my @F; my @U;
174: for my $l (@lines) {
1.11 harris41 175: chop $l;
1.8 harris41 176: @F=split(/\:/,$l);
177: if ($F[0] eq $username) {($userid,$useroldcryptpwd)=($F[2],$F[1]); @U=@F;}
178: }
1.5 harris41 179:
1.8 harris41 180: # Verify existence of user
181: if (!defined($userid)) {
182: print "Error. User $username does not exist.\n" unless $noprint;
183: unlink('/tmp/lock_lcpasswd');
184: exit 5;
185: }
1.2 harris41 186:
1.8 harris41 187: # Construct new password entry (random salt)
1.10 harris41 188: my $newcryptpwd=crypt($password1,(join '', ('.', '/', 0..9, 'A'..'Z', 'a'..'z')[rand 64, rand 64]));
1.8 harris41 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");
1.10 harris41 224: print OUT $password1; print OUT "\n";
225: print OUT $password1; print OUT "\n";
1.8 harris41 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:
1.12 harris41 232: system('/bin/chmod','-R','0660',"/home/$safeusername");
233: system('/bin/chmod','0770',"/home/$safeusername");
234: mkdir "/home/$safeusername/public_html",0770;
1.11 harris41 235: open OUT,">/home/$safeusername/public_html/index.html";
1.8 harris41 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;
1.11 harris41 258: system('/bin/chown','-R',"$safeusername:$safeusername","/home/$safeusername");
1.8 harris41 259: &disable_root_capability;
260: unlink('/tmp/lock_lcpasswd');
261: exit 0;
1.1 harris41 262:
1.5 harris41 263: # ----------------------------------------------------------- have setuid script run as root
264: sub enable_root_capability {
265: if ($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: }
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