--- loncom/Attic/lchtmldir 2004/09/02 18:59:24 1.8
+++ loncom/Attic/lchtmldir 2008/05/30 13:37:48 1.21
@@ -2,6 +2,8 @@
# The Learning Online Network with CAPA
#
+# $Id: lchtmldir,v 1.21 2008/05/30 13:37:48 raeburn Exp $
+#
# Copyright Michigan State University Board of Trustees
#
# This file is part of the LearningOnline Network with CAPA (LON-CAPA).
@@ -41,7 +43,7 @@
# NSCL
# Michigan State University8
# East Lansing, MI 48824-1321
-
+#
# General flow of control:
# 1. Validate process state (must be run as www).
# 2. Validate parameters: Need two parameters:
@@ -61,17 +63,23 @@
# - internal - www:www/2775
# - local - www:www/2775
#
-
+#
#
# Take a few precautions to be sure that we're not vulnerable to trojan
# horses and other fine issues:
#
use strict;
+use Fcntl qw(:mode);
+use DirHandle;
+use POSIX;
+use lib '/home/httpd/lib/perl/';
+use LONCAPA qw(:match);
$ENV{'PATH'} = '/bin:/usr/bin:/usr/local/sbin:/home/httpd/perl';
delete @ENV{qw{IFS CDPATH ENV BASH_ENV}};
-my $DEBUG = 0; # .nonzero -> Debug printing enabled.
+my $DEBUG = 1; # .nonzero -> Debug printing enabled.
+my $path_sep = "/"; # Unix like operating systems.
# If the UID of the running process is not www exit with error.
@@ -121,14 +129,14 @@ if( $authentication ne "unix:" &&
$authentication ne "localauth:") {
if($DEBUG) {
print("Invalid authentication parameter: ".$authentication."\n");
- print("Should be one of: unix, internal, krb4, localauth\n");
+ print("Should be one of-- unix: internal: krb4: krb5: localauth:\n");
}
exit 3;
}
# Untaint the username.
-my $match = $username =~ /^(\w+)$/;
+my $match = $username =~ /^($match_username)$/;
my $patt = $1;
if($DEBUG) {
@@ -140,7 +148,7 @@ my $safeuser = $patt;
if($DEBUG) {
print("Save username = $safeuser \n");
}
-if(($username ne $safeuser) or ($safeuser!~/^[A-za-z]/)) {
+if($username ne $safeuser) {
if($DEBUG) {
print("User name $username had illegal characters\n");
}
@@ -150,37 +158,57 @@ if(($username ne $safeuser) or ($safeuse
#untaint the base directory require that the dir contain only
# alphas, / numbers or underscores, and end in /$safeuser
-$dir =~ /(^([\w\/]+))/;
-my $dirtry1 = $1;
-$dir =~ /$\/$safeuser/;
-my $dirtry2 = $1;
+my ($allowed_dir) = ($dir =~ m{(^([/]|$match_username)+)});
+
+my $has_correct_end = ($dir =~ m{/\Q$safeuser\E$});
-if(($dirtry1 ne $dir) or ($dirtry2 ne $dir)) {
+if(($allowed_dir ne $dir) or (!$has_correct_end)) {
if ($DEBUG) {
print("Directory $dir is not a valid home for $safeuser\n");
}
exit 5;
}
-
# As root, create the directory.
-my $fulldir = $dirtry1."/public_html";
+my $homedir = $allowed_dir;
+my $fulldir = $homedir."/public_html";
+
if($DEBUG) {
print("Full directory path is: $fulldir \n");
}
-if(!( -e $dirtry1)) {
+if(!( -e $homedir)) {
if($DEBUG) {
- print("User's home directory $dirtry1 does not exist\n");
+ print("User's home directory $homedir does not exist\n");
}
if ($authentication eq "unix:") {
exit 6;
}
}
+if ($authentication eq "unix:") {
+ # check whether group $safeuser exists.
+ my $usergroups = `id -nG $safeuser`;
+ if (! grep /^$safeuser$/, split(/\s+/,$usergroups)) {
+ if($DEBUG) {
+ print("Group \"$safeuser\" does not exist or $safeuser is not a member of that group.\n");
+ }
+ exit 7;
+ }
+}
+
+
+
&EnableRoot;
+# If authentication is internal and the top level directory exists
+# give it the right permissions (in case this is a modification.
+
+if ($authentication eq "internal:") {
+ chmod(0711, $homedir); # so www can enter ~/public_html.
+}
+
&System("/bin/mkdir -p $fulldir") unless (-e $fulldir);
unless(-e $fulldir."/index.html") {
open OUT,">".$fulldir."/index.html";
@@ -207,20 +235,53 @@ it available to students and other instr
END
close OUT;
}
-&System("/bin/chmod 02775 $fulldir");
-&System("/bin/chmod 0775 $fulldir"."/index.html");
+
+&System("/bin/chmod 02770 $fulldir");
+&System("/bin/chmod 0770 $fulldir"."/index.html");
# Based on the authentiation mode, set the ownership of the directory.
if($authentication eq "unix:") { # Unix mode authentication...
- &System("/bin/chown -R $safeuser".":".$safeuser." ".$fulldir);
+ print "Unix auth\n";
+ &System("/bin/chown -R $safeuser:$safeuser"." ".$fulldir);
&JoinGroup($safeuser);
} else {
# Internal, Kerberos, and Local authentication are for users
# who do not have unix accounts on the system. Therefore we
# will give ownership of their public_html directories to www:www
- &System("/bin/chown -R www:www ".$fulldir);
+ # If the user is an internal auth user, the rest of the directory tree
+ # gets owned by root. This chown is needed in case what's really happening
+ # is that a file system user is being demoted to internal user...
+
+ if($authentication eq "internal:") {
+ # In case the user was a unix/filesystem authenticated user,
+ # we'll take a bit of time here to write a script in the
+ # user's home directory that can reset ownerships and permissions
+ # back the way the used to be.
+
+ # This can take long enough for lond to time out, so we'll do it
+ # in a separate process that we'll not wait for.
+ #
+ my $fpid = fork;
+ if($fpid) {
+ &DisableRoot;
+ exit 0;
+ } else {
+ print "Forked\n";
+ POSIX::setsid(); # Disassociate from parent.
+ print "Separate session\n";
+ &write_restore_script($homedir);
+ print "Restore script written\n";
+ &System("/bin/chown -R root:root ".$homedir);
+ &System("/bin/chown -R www:www ".$fulldir);
+ print "Exiting\n";
+ exit 0;
+ }
+ } else {
+ &System("/bin/chown -R www:www ".$fulldir);
+ }
+
}
&DisableRoot;
@@ -262,7 +323,10 @@ sub DisableRoot {
print("Disable root: id = ".$>."\n");
}
}
-
+#
+# Join the www user to the user's group.
+# we must be running with euid as root at this time.
+#
sub JoinGroup {
my $usergroup = shift;
@@ -281,7 +345,16 @@ sub JoinGroup {
}
exit 6;
}
-
+ if (-e '/var/run/httpd.pid') {
+ open(PID,'/var/run/httpd.pid');
+ my $pid=<PID>;
+ close(PID);
+ my ($safepid) = $pid=~ /(\d+)/;
+ $pid = $safepid;
+ if ($pid) {
+ my $status = system("kill -USR1 $safepid");
+ }
+ }
}
@@ -295,5 +368,136 @@ sub System {
}
+
+
+
+#
+# This file contains code to recursively process
+# a Directory. This is a bit more powerful
+# than File::Find in that we pass the full
+# stat info to the processing function.
+# For each file in the specified directory subtree,
+# The user's Code reference is invoked for all files, regular and otherwise
+# except:
+# ., ..
+#
+# Parameters:
+# code_ref - Code reference, invoked for each file in the tree.
+# as follows: CodeRef(directory, name, statinfo)
+# directory the path to the directory holding the file.
+# name the name of the file within Directory.
+# statinfo a reference to the stat of the file.
+# start_dir - The starting point of the directory walk.
+#
+# NOTE:
+# Yes, we could have just used File::Find, but since we have to get the
+# stat anyway, this is actually simpler, as File::Find would have gotten
+# the stat to figure out the file type and then we would have gotten it
+# again.
+#
+
+sub process_tree {
+ my ($code_ref, $start_dir) = @_;
+
+ my $dir = new DirHandle $start_dir;
+ if (!defined($dir)) {
+ print "Failed to open dirhandle: $start_dir\n";
+ }
+
+ # Now iterate through this level of the tree:
+
+ while (defined (my $name = $dir->read)) {
+ next if $name =~/^\.\.?$/; # Skip ., .. (see cookbook pg 319)
+
+ my $full_name = $start_dir.$path_sep.$name; # Full filename path.
+ my @stat_info = lstat($full_name);
+ my $mode = $stat_info[2];
+ my $type = $mode & 0170000; # File type.
+
+ # Unless the file type is a symlink, call the user code:
+
+ unless ($type == S_IFLNK) {
+ &$code_ref($start_dir, $name, \@stat_info);
+ }
+
+ # If the entry is a directory, we need to recurse:
+
+
+ if (($type == S_IFDIR) != 0) {
+ &process_tree($code_ref, $full_name);
+ }
+ }
+
+}
+#
+# Callback from process_tree to write the script lines
+# requried to restore files to current ownership and permission.
+# Parameters:
+# dir - Name of the directory the file lives in.
+# name - Name of the file itself.
+# statinfo - Array from lstat called on the file.
+#
+#
+sub write_script {
+ my ($dir, $name, $statinfo) = @_;
+
+ my $fullname = $dir.$path_sep.$name;
+
+ # We're going to '' the name, but we need to deal with embedded
+ # ' characters. Using " is much worse as we'd then have to
+ # escape all the shell escapes too. This way all we need
+ # to do is replace ' with '\''
+
+ $fullname =~ s/\'/\'\\\'\'/g;
+
+ my $perms = $statinfo->[2] & 0777; # Just permissions.
+ printf CHMODSCRIPT "chmod 0%o '%s'\n", $perms, $fullname;
+ printf CHMODSCRIPT "chown %d:%d '%s'\n", $statinfo->[4], $statinfo->[5],
+ $fullname
+
+
+}
+#
+# Write a script in the user's home directory that can restore
+# the permissions and ownerhips of all the files in the directory
+# tree to their current ownerships and permissions. This is done
+# prior to making the user into an internally authenticated user
+# in case they were previously file system authenticated and
+# need to go back.
+# The file we will create will be of the form
+# restore_n.sh Where n is a number that we will keep
+# incrementing as needed until there isn't a file by that name.
+#
+# Parameters:
+# dir - Path to the user's home directory.
+#
+sub write_restore_script {
+ my ($dir) = @_;
+
+ # Create a unique file:
+
+ my $version_number = 0;
+ my $filename = 'restore_'.$version_number.'.sh';
+ my $full_name = $dir.$path_sep.$filename;
+
+ while(-e $full_name) {
+ $version_number++;
+ $filename = 'restore_'.$version_number.'.sh';
+ $full_name = $dir.$path_sep.$filename;
+ }
+ # $full_name is the full path of a file that does not yet exist
+ # of the form we want:
+
+ open(CHMODSCRIPT, "> $full_name");
+
+ &process_tree(\&write_script, $dir);
+
+ close(CHMODSCRIPT);
+
+ chmod(0750, $full_name);
+
+}
+
+