Annotation of loncom/lcinstallfile, revision 1.2

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: #
1.2     ! foxr       65: my $noprint = 0;
1.1       foxr       66: #
                     67: #   Ensure we are www:
                     68: #
                     69: # 
                     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) {
1.2     ! foxr       83:     print("Usage: lcinstallfile sourcepath destfile\n") unless $noprint;
1.1       foxr       84:     exit 2;
                     85: }
1.2     ! foxr       86: my $sourcepath = $ARGV[0];
1.1       foxr       87: my $destfile  = $ARGV[1];
                     88: 
1.2     ! foxr       89: 
        !            90: 
1.1       foxr       91: # Ensure the source file exists, and root can write it.:
                     92: 
1.2     ! foxr       93: # since this is a setuid program, the sourcepath and destfile
        !            94: # must be pattern extracted else they are considered insecure and
        !            95: # therefore not validated.  
        !            96: # loncapa table files are all of the form.
        !            97: #  something.tab where something is all letters and _'s.
        !            98: #
        !            99: if ($sourcepath =~ /^(\w+\.tab)$/) {
        !           100:     $sourcepath = $1;
        !           101: } else {
        !           102:     print ("Invalid characters in filename $sourcepath \n") unless $noprint;
        !           103:     exit 7;
        !           104: }
        !           105: 
        !           106: 
1.1       foxr      107: if (! -r $sourcepath) {
                    108:     print("File $sourcepath either does not exist or cannot be read") unless $noprint;
                    109:     exit 4;
                    110:     
                    111: }
1.2     ! foxr      112: &enable_root_capability;
        !           113: 
1.1       foxr      114: #
                    115: #  Figure out where the lontab directory is and create the destinationfile name:
                    116: #
                    117: #  We're not allowed to create new files, only replace existing files
                    118: #  so ensure that the final destination file actually exists.
                    119: #
                    120: my $config_vars = LONCAPA::Configuration::read_conf('loncapa.conf');
1.2     ! foxr      121: my %config      = %{$config_vars};
1.1       foxr      122: my $tab_dir     = $config{'lonTabDir'};
                    123: 
1.2     ! foxr      124: my $final_file  = $tab_dir.'/'.$destfile;
        !           125: 
        !           126: #
        !           127: # Now sanitize the final file:
        !           128: 
        !           129: if ($final_file =~ /^([\w\/]+\.tab)$/) {
        !           130:     $final_file = $1;
        !           131: } else {
        !           132:     print ("$final_file failed regexp match\n") unless $noprint;
        !           133:     exit 7;
        !           134: }
1.1       foxr      135: 
                    136: if (! -w $final_file) {
                    137:     &disable_root_capability;
                    138:     print("The $final_file is either not writable, or does not exist.\n") unless $noprint;
                    139:     exit 5;
                    140: }
                    141: #
                    142: # Copy the destination file to a backup:
                    143: #
1.2     ! foxr      144: if (!copy($final_file, $final_file.'.backup')) {
1.1       foxr      145:     &disable_root_capability;
                    146:     print ("Failed to create backup copy of $final_file\n") unless $noprint;
                    147:     exit 6;
                    148: }
1.2     ! foxr      149: &enable_root_capability;
1.1       foxr      150: 
                    151: #  Install the new file to a temp file in the same dir so it can be mv'd in place
                    152: #  this prevents the possibility we wind up with a partial file.:
                    153: 
1.2     ! foxr      154: if (!copy($sourcepath, $final_file.'.new')) {
1.1       foxr      155:     &disable_root_capability;
                    156:     print("Failed to copy $sourcepath to a tempfile\n") unless $noprint;
                    157:     exit 6;
                    158: }
                    159: #
                    160: #  Move the temp file to the final file
                    161: #
1.2     ! foxr      162: if (!rename($final_file.'.new', $final_file)) {
1.1       foxr      163:     &disable_root_capability;
1.2     ! foxr      164:     print ("Failed to move installed file $final_file.new to final resting place\n")
1.1       foxr      165: 	unless $noprint;
                    166:     exit 6;
                    167: }
                    168: 
                    169: #  Ready to exit with success
                    170: 
1.2     ! foxr      171: &disable_root_capability;
        !           172: print ("$sourcepath installed to $final_file\n") unless $noprint;
1.1       foxr      173: exit 0;
                    174: 
1.2     ! foxr      175: 
1.1       foxr      176: #-------------------------------------------------------------------------
                    177: #
                    178: #  subs that control the setuid-edness of the program.
                    179: 
1.2     ! foxr      180: #  have setuid script run as root
1.1       foxr      181: sub enable_root_capability {
                    182:     if ($wwwid==$>) {
                    183: 	($<,$>)=($>,0);
                    184: 	($(,$))=($),0);
                    185:     }
                    186:     else {
                    187: 	# root capability is already enabled
                    188:     }
                    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: }

FreeBSD-CVSweb <freebsd-cvsweb@FreeBSD.org>