Annotation of loncom/lcinstallfile, revision 1.4
1.1 foxr 1: #!/usr/bin/perl
2: #
1.4 ! raeburn 3: # Copyright Michigan State University Board of Trustees
! 4: #
! 5: # $Id: lcinstallfile,v 1.4 2009/05/13 16:00:00 raeburn Exp $
1.1 foxr 6: #
7: # This file is part of the LearningOnline Network with CAPA (LON-CAPA).
8: #
9: # LON-CAPA is free software; you can redistribute it and/or modify
10: # it under the terms of the GNU General Public License as published by
11: # the Free Software Foundation; either version 2 of the License, or
12: # (at your option) any later version.
13: #
14: # LON-CAPA is distributed in the hope that it will be useful,
15: # but WITHOUT ANY WARRANTY; without even the implied warranty of
16: # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
17: # GNU General Public License for more details.
18: #
19: # You should have received a copy of the GNU General Public License
20: # along with LON-CAPA; if not, write to the Free Software
21: # Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
22: #
23: # /home/httpd/html/adm/gpl.txt
24: #
25: #
26: #
1.4 ! raeburn 27: # 2/17/2009 - Ron Fox
1.2 foxr 28: #
29: # http://www.lon-capa.org/
1.1 foxr 30: #
31: # This file is a setuid script that allows lond or other www programs to install
32: # a file in the lon capa table directory.
33: #
34: # Invocation is as follows:
35: # lcinstallfile source_file_name dest_name
36: #
37: # source_file_name - The full path for the source file.
38: # dest_name - The destination filename. This will always be in the
39: # table file directory for this server.
40: #
41:
42:
43: use strict;
44:
1.4 ! raeburn 45: use lib "/home/httpd/lib/perl"; # Adjust if loncapa lib isn't installed here.
1.1 foxr 46: use LONCAPA;
47: use LONCAPA::Configuration;
48: use IO::File;
1.2 foxr 49: use File::Copy;
50:
51:
1.1 foxr 52:
53: #
54: # Exit codes:
55: #
56: # 0 - ok
57: # 1 - Initial user ID was not www
58: # 3 - Usage error not enough command line arguments.
59: # 4 - source_file_name does not exist.
60: # 5 - destination file does not exist (not allowed to create new files).
61: # 6 - Some file operation failed.
1.2 foxr 62: # 7 - Invalid table filename.
1.1 foxr 63: #
1.3 foxr 64: my $noprint = 1;
1.1 foxr 65: #
66: # Ensure we are www:
67: #
68: #
1.3 foxr 69: print ("In lcinstallfile\n") unless $noprint;
1.1 foxr 70:
71: my $wwwid=getpwnam('www');
72: &disable_root_capability;
73: if ($wwwid!=$>) {
74: print("User ID mismatch. This program must be run as user 'www'\n")
75: unless $noprint;
76: exit 1;
77: }
78: #
79: # Ensure we have the right number of command args:
80: #
81: my $argc = scalar(@ARGV);
82: if ($argc != 2) {
1.3 foxr 83: print("Usage: lcinstallfile sourcepath destfile had $argc parameters\n") unless $noprint;
1.1 foxr 84: exit 2;
85: }
1.2 foxr 86: my $sourcepath = $ARGV[0];
1.1 foxr 87: my $destfile = $ARGV[1];
88:
1.3 foxr 89: print("From: $sourcepath to: $destfile\n") unless $noprint;
1.2 foxr 90:
91:
1.1 foxr 92: # Ensure the source file exists, and root can write it.:
93:
1.2 foxr 94: # since this is a setuid program, the sourcepath and destfile
95: # must be pattern extracted else they are considered insecure and
96: # therefore not validated.
97: # loncapa table files are all of the form.
98: # something.tab where something is all letters and _'s.
99: #
1.3 foxr 100: if ($sourcepath =~ /^([\w\/]+\.\w+)$/) {
1.2 foxr 101: $sourcepath = $1;
102: } else {
1.3 foxr 103: print ("Invalid characters in filename '$sourcepath' \n") unless $noprint;
1.2 foxr 104: exit 7;
105: }
106:
107:
1.1 foxr 108: if (! -r $sourcepath) {
109: print("File $sourcepath either does not exist or cannot be read") unless $noprint;
110: exit 4;
111:
112: }
1.2 foxr 113: &enable_root_capability;
114:
1.1 foxr 115: #
116: # Figure out where the lontab directory is and create the destinationfile name:
117: #
118: # We're not allowed to create new files, only replace existing files
119: # so ensure that the final destination file actually exists.
120: #
121:
1.2 foxr 122:
123: #
124: # Now sanitize the final file:
125:
1.3 foxr 126: my $final_file;
127: if ($destfile =~ /^([\w\/]+\.\w+)$/) {
1.2 foxr 128: $final_file = $1;
129: } else {
1.3 foxr 130: print ("'$final_file' failed regexp match\n") unless $noprint;
1.2 foxr 131: exit 7;
132: }
1.1 foxr 133:
134: if (! -w $final_file) {
135: &disable_root_capability;
136: print("The $final_file is either not writable, or does not exist.\n") unless $noprint;
137: exit 5;
138: }
139: #
140: # Copy the destination file to a backup:
141: #
1.2 foxr 142: if (!copy($final_file, $final_file.'.backup')) {
1.1 foxr 143: &disable_root_capability;
144: print ("Failed to create backup copy of $final_file\n") unless $noprint;
145: exit 6;
146: }
1.2 foxr 147: &enable_root_capability;
1.1 foxr 148:
149: # Install the new file to a temp file in the same dir so it can be mv'd in place
150: # this prevents the possibility we wind up with a partial file.:
151:
1.2 foxr 152: if (!copy($sourcepath, $final_file.'.new')) {
1.1 foxr 153: &disable_root_capability;
154: print("Failed to copy $sourcepath to a tempfile\n") unless $noprint;
155: exit 6;
156: }
157: #
158: # Move the temp file to the final file
159: #
1.2 foxr 160: if (!rename($final_file.'.new', $final_file)) {
1.1 foxr 161: &disable_root_capability;
1.2 foxr 162: print ("Failed to move installed file $final_file.new to final resting place\n")
1.1 foxr 163: unless $noprint;
164: exit 6;
165: }
166:
167: # Ready to exit with success
168:
1.2 foxr 169: &disable_root_capability;
170: print ("$sourcepath installed to $final_file\n") unless $noprint;
1.1 foxr 171: exit 0;
172:
1.2 foxr 173:
1.1 foxr 174: #-------------------------------------------------------------------------
175: #
176: # subs that control the setuid-edness of the program.
177:
1.2 foxr 178: # have setuid script run as root
1.1 foxr 179: sub enable_root_capability {
180: if ($wwwid==$>) {
181: ($<,$>)=($>,0);
182: ($(,$))=($),0);
1.4 ! raeburn 183: } else {
1.1 foxr 184: # root capability is already enabled
185: }
1.3 foxr 186: print ("Effective uid = $>\n");
1.1 foxr 187: return $>;
188: }
189:
1.2 foxr 190: # have setuid script run as www
1.1 foxr 191: sub disable_root_capability {
192: if ($wwwid==$<) {
193: ($<,$>)=($>,$<);
194: ($(,$))=($),$();
1.4 ! raeburn 195: } else {
1.1 foxr 196: # root capability is already disabled
197: }
198: }
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