Annotation of loncom/lcuseradd, revision 1.6
1.1 harris41 1: #!/usr/bin/perl
2: #
3: # lcuseradd
4: #
5: # Scott Harrison
6: # October 27, 2000
7:
8: use strict;
9:
10: # This script is a setuid script that should
11: # be run by user 'www'. It creates a /home/USERNAME directory
12: # as well as a /home/USERNAME/public_html directory.
13: # It adds user entries to
14: # /etc/passwd and /etc/groups.
1.2 harris41 15: # Passwords are set with lcpasswd.
16: # www becomes a member of this user group.
1.1 harris41 17:
18: # Standard input usage
19: # First line is USERNAME
20: # Second line is PASSWORD
1.3 harris41 21: # Third line is PASSWORD
1.1 harris41 22:
1.3 harris41 23: # Command-line arguments [USERNAME] [PASSWORD] [PASSWORD]
1.1 harris41 24: # Yes, but be very careful here (don't pass shell commands)
25: # and this is only supported to allow perl-system calls.
26:
1.4 harris41 27: # Usage within code
28: #
29: # $exitcode=system("/home/httpd/perl/lcuseradd","NAME","PASSWORD1","PASSWORD2")/256;
30: # print "uh-oh" if $exitcode;
31:
32: # These are the exit codes.
33:
1.1 harris41 34: # Security
35: $ENV{'PATH'}=""; # Nullify path information.
36: $ENV{'BASH_ENV'}=""; # Nullify shell environment information.
1.2 harris41 37:
1.4 harris41 38: # Do not print error messages if there are command-line arguments
39: my $noprint=0;
40: if (@ARGV) {
41: $noprint=1;
42: }
43:
44: # Read in /etc/passwd, and make sure this process is running from user=www
45: open (IN, "</etc/passwd");
46: my @lines=<IN>;
47: close IN;
48: my $wwwid;
49: for my $l (@lines) {
50: chop $l;
51: my @F=split(/\:/,$l);
52: if ($F[0] eq 'www') {$wwwid=$F[2];}
53: }
54: if ($wwwid!=$<) {
55: print("User ID mismatch. This program must be run as user 'www'\n") unless $noprint;
56: exit 1;
57: }
58: &disable_root_capability;
59:
60: # Handle case of another lcpasswd process
61: unless (&try_to_lock("/tmp/lock_lcpasswd")) {
62: print "Error. Too many other simultaneous password change requests being made.\n" unless $noprint;
63: exit 4;
64: }
65:
66: # Gather input. Should be 3 values (user name, password 1, password 2).
67: my @input;
1.5 harris41 68: if (@ARGV==3) {
1.4 harris41 69: @input=@ARGV;
70: }
71: elsif (@ARGV) {
72: print("Error. This program needs 3 command-line arguments (username, password 1, password 2).\n") unless $noprint;
73: unlink('/tmp/lock_lcpasswd');
74: exit 2;
75: }
76: else {
77: @input=<>;
1.5 harris41 78: if (@input!=3) {
1.4 harris41 79: print("Error. Three lines should be entered into standard input.\n") unless $noprint;
80: unlink('/tmp/lock_lcpasswd');
81: exit 3;
82: }
83: map {chop} @input;
84: }
85:
86: my ($username,$password1,$password2)=@input;
87: $username=~/^(\w+)$/;
88: my $safeusername=$1;
1.5 harris41 89:
90: if ($password1 ne $password2) {
1.6 ! harris41 91: print "Error. Password mismatch.\n" unless $noprint;
1.5 harris41 92: unlink('/tmp/lock_lcpasswd');
93: exit 7;
94: }
1.4 harris41 95:
96: &enable_root_capability;
97:
1.3 harris41 98: # Add user entry to /etc/passwd and /etc/groups in such
99: # a way that www is a member of the user-specific group
100:
1.5 harris41 101: if (system('/usr/sbin/useradd','-c','LON-CAPA user',$safeusername)) {
1.6 ! harris41 102: print "Error. Something went wrong with the addition of user \"$safeusername\".\n" unless $noprint;
1.4 harris41 103: unlink('/tmp/lock_lcpasswd');
104: exit 5;
105: }
1.5 harris41 106: if (system('/usr/sbin/usermod','-G',$safeusername,'www')) {
1.6 ! harris41 107: print "Error. Could not make www a member of the group \"$safeusername\".\n" unless $noprint;
1.5 harris41 108: unlink('/tmp/lock_lcpasswd');
109: exit 6;
110: }
111:
112: # Set password with lcpasswd-style algorithm (which creates smbpasswd entry).
113: # I cannot place a direct shell call to lcpasswd since I have to allow
114: # for crazy characters in the password, and the setuid environment of perl
115: # requires me to make everything safe.
116:
1.2 harris41 117:
1.1 harris41 118:
1.5 harris41 119: # ----------------------------------------------------------- have setuid script run as root
120: sub enable_root_capability {
121: if ($wwwid==$>) {
122: ($<,$>)=($>,$<);
123: ($(,$))=($),$();
124: }
125: else {
126: # root capability is already enabled
127: }
128: return $>;
129: }
130:
131: # ----------------------------------------------------------- have setuid script run as www
132: sub disable_root_capability {
133: if ($wwwid==$<) {
134: ($<,$>)=($>,$<);
135: ($(,$))=($),$();
136: }
137: else {
138: # root capability is already disabled
139: }
140: }
141:
142: # ----------------------------------- make sure that another lcpasswd process isn't running
143: sub try_to_lock {
144: my ($lockfile)=@_;
145: my $currentpid;
146: my $lastpid;
147: # Do not manipulate lock file as root
148: if ($>==0) {
149: return 0;
150: }
151: # Try to generate lock file.
152: # Wait 3 seconds. If same process id is in
153: # lock file, then assume lock file is stale, and
154: # go ahead. If process id's fluctuate, try
155: # for a maximum of 10 times.
156: for (0..10) {
157: if (-e $lockfile) {
158: open(LOCK,"<$lockfile");
159: $currentpid=<LOCK>;
160: close LOCK;
161: if ($currentpid==$lastpid) {
162: last;
163: }
164: sleep 3;
165: $lastpid=$currentpid;
166: }
167: else {
168: last;
169: }
170: if ($_==10) {
171: return 0;
172: }
173: }
174: open(LOCK,">$lockfile");
175: print LOCK $$;
176: close LOCK;
177: return 1;
178: }
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