Annotation of loncom/lcinstallfile, revision 1.3
1.1 foxr 1: #!/usr/bin/perl
2: #
3: ## Copyright Michigan State University Board of Trustees
4: #
5: # This file is part of the LearningOnline Network with CAPA (LON-CAPA).
6: #
7: # LON-CAPA is free software; you can redistribute it and/or modify
8: # it under the terms of the GNU General Public License as published by
9: # the Free Software Foundation; either version 2 of the License, or
10: # (at your option) any later version.
11: #
12: # LON-CAPA is distributed in the hope that it will be useful,
13: # but WITHOUT ANY WARRANTY; without even the implied warranty of
14: # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15: # GNU General Public License for more details.
16: #
17: # You should have received a copy of the GNU General Public License
18: # along with LON-CAPA; if not, write to the Free Software
19: # Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
20: #
21: # /home/httpd/html/adm/gpl.txt
22: #
23: #
24: #
25: # 2/17/2009 - Ron FOx
26: # $Id:
1.2 foxr 27: #
28: # http://www.lon-capa.org/
1.1 foxr 29: #
30: # This file is a setuid script that allows lond or other www programs to install
31: # a file in the lon capa table directory.
32: #
33: # Invocation is as follows:
34: # lcinstallfile source_file_name dest_name
35: #
36: # source_file_name - The full path for the source file.
37: # dest_name - The destination filename. This will always be in the
38: # table file directory for this server.
39: #
40:
41:
42: use strict;
43:
1.2 foxr 44: my $LONCAPAHOME = '/home/httpd'; # Adjust if loncapa isn't installed here.
1.1 foxr 45:
1.2 foxr 46: use lib "/home/httpd/lib/perl";
1.1 foxr 47: use LONCAPA;
48: use LONCAPA::Configuration;
49: use IO::File;
1.2 foxr 50: use File::Copy;
51:
52:
1.1 foxr 53:
54: #
55: # Exit codes:
56: #
57: # 0 - ok
58: # 1 - Initial user ID was not www
59: # 3 - Usage error not enough command line arguments.
60: # 4 - source_file_name does not exist.
61: # 5 - destination file does not exist (not allowed to create new files).
62: # 6 - Some file operation failed.
1.2 foxr 63: # 7 - Invalid table filename.
1.1 foxr 64: #
1.3 ! foxr 65: my $noprint = 1;
1.1 foxr 66: #
67: # Ensure we are www:
68: #
69: #
1.3 ! foxr 70: print ("In lcinstallfile\n") unless $noprint;
1.1 foxr 71:
72: my $wwwid=getpwnam('www');
73: &disable_root_capability;
74: if ($wwwid!=$>) {
75: print("User ID mismatch. This program must be run as user 'www'\n")
76: unless $noprint;
77: exit 1;
78: }
79: #
80: # Ensure we have the right number of command args:
81: #
82: my $argc = scalar(@ARGV);
83: if ($argc != 2) {
1.3 ! foxr 84: print("Usage: lcinstallfile sourcepath destfile had $argc parameters\n") unless $noprint;
1.1 foxr 85: exit 2;
86: }
1.2 foxr 87: my $sourcepath = $ARGV[0];
1.1 foxr 88: my $destfile = $ARGV[1];
89:
1.3 ! foxr 90: print("From: $sourcepath to: $destfile\n") unless $noprint;
1.2 foxr 91:
92:
1.1 foxr 93: # Ensure the source file exists, and root can write it.:
94:
1.2 foxr 95: # since this is a setuid program, the sourcepath and destfile
96: # must be pattern extracted else they are considered insecure and
97: # therefore not validated.
98: # loncapa table files are all of the form.
99: # something.tab where something is all letters and _'s.
100: #
1.3 ! foxr 101: if ($sourcepath =~ /^([\w\/]+\.\w+)$/) {
1.2 foxr 102: $sourcepath = $1;
103: } else {
1.3 ! foxr 104: print ("Invalid characters in filename '$sourcepath' \n") unless $noprint;
1.2 foxr 105: exit 7;
106: }
107:
108:
1.1 foxr 109: if (! -r $sourcepath) {
110: print("File $sourcepath either does not exist or cannot be read") unless $noprint;
111: exit 4;
112:
113: }
1.2 foxr 114: &enable_root_capability;
115:
1.1 foxr 116: #
117: # Figure out where the lontab directory is and create the destinationfile name:
118: #
119: # We're not allowed to create new files, only replace existing files
120: # so ensure that the final destination file actually exists.
121: #
122:
1.2 foxr 123:
124: #
125: # Now sanitize the final file:
126:
1.3 ! foxr 127: my $final_file;
! 128: if ($destfile =~ /^([\w\/]+\.\w+)$/) {
1.2 foxr 129: $final_file = $1;
130: } else {
1.3 ! foxr 131: print ("'$final_file' failed regexp match\n") unless $noprint;
1.2 foxr 132: exit 7;
133: }
1.1 foxr 134:
135: if (! -w $final_file) {
136: &disable_root_capability;
137: print("The $final_file is either not writable, or does not exist.\n") unless $noprint;
138: exit 5;
139: }
140: #
141: # Copy the destination file to a backup:
142: #
1.2 foxr 143: if (!copy($final_file, $final_file.'.backup')) {
1.1 foxr 144: &disable_root_capability;
145: print ("Failed to create backup copy of $final_file\n") unless $noprint;
146: exit 6;
147: }
1.2 foxr 148: &enable_root_capability;
1.1 foxr 149:
150: # Install the new file to a temp file in the same dir so it can be mv'd in place
151: # this prevents the possibility we wind up with a partial file.:
152:
1.2 foxr 153: if (!copy($sourcepath, $final_file.'.new')) {
1.1 foxr 154: &disable_root_capability;
155: print("Failed to copy $sourcepath to a tempfile\n") unless $noprint;
156: exit 6;
157: }
158: #
159: # Move the temp file to the final file
160: #
1.2 foxr 161: if (!rename($final_file.'.new', $final_file)) {
1.1 foxr 162: &disable_root_capability;
1.2 foxr 163: print ("Failed to move installed file $final_file.new to final resting place\n")
1.1 foxr 164: unless $noprint;
165: exit 6;
166: }
167:
168: # Ready to exit with success
169:
1.2 foxr 170: &disable_root_capability;
171: print ("$sourcepath installed to $final_file\n") unless $noprint;
1.1 foxr 172: exit 0;
173:
1.2 foxr 174:
1.1 foxr 175: #-------------------------------------------------------------------------
176: #
177: # subs that control the setuid-edness of the program.
178:
1.2 foxr 179: # have setuid script run as root
1.1 foxr 180: sub enable_root_capability {
181: if ($wwwid==$>) {
182: ($<,$>)=($>,0);
183: ($(,$))=($),0);
184: }
185: else {
186: # root capability is already enabled
187: }
1.3 ! foxr 188: print ("Effective uid = $>\n");
1.1 foxr 189: return $>;
190: }
191:
1.2 foxr 192: # have setuid script run as www
1.1 foxr 193: sub disable_root_capability {
194: if ($wwwid==$<) {
195: ($<,$>)=($>,$<);
196: ($(,$))=($),$();
197: }
198: else {
199: # root capability is already disabled
200: }
201: }
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