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# Copyright (C) 1999, 2000 Jay Beale
# Licensed under the GNU General Public License
package Bastille::DNS;
use lib "/usr/lib";
use Bastille::API;
@ENV="";
$ENV{PATH}="";
$ENV{CDPATH}=".";
$ENV{BASH_ENV}="";
######## TO DO: Convert the chown line to API functions, so we don't
######### have to use GLOBAL_PREFIX
#######################################################################
## DNS/BIND/NAMED ##
#######################################################################
&chrootBIND;
&DeactivateNamed;
sub chrootBIND {
if ( &getGlobalConfig("DNS","chrootbind") eq "Y" ) {
&ActionLog("# sub chrootBIND\n");
# Only chroot bind if we are running on a Red Hat / Mandrake / HP-UX
# system and we haven't already chroot'ed it...
if($GLOBAL_DISTRO =~ "^HP-UX"){
my $extrasteps=0;
# create non-privileged user and group named
my $groupadd = 'PATH="/usr/bin"; ' . &getGlobal('BIN',"groupadd") . " named";
my $groupdel = 'PATH="/usr/bin"; ' . &getGlobal('BIN',"groupdel") . " named";
if (! &B_System($groupadd,$groupdel)) {
$extrasteps = 1;
}
my $jail = &getGlobal('BDIR',"jail");
my $useradd = 'PATH="/usr/bin"; ' . &getGlobal('BIN',"useradd") .
" -g named -d $jail/bind -s /usr/bin/false named";
my $userdel = 'PATH="/usr/bin"; ' . &getGlobal('BIN',"userdel") . " named";
if (! &B_System($useradd, $userdel)) {
$extrasteps = 1;
}
# install generic chroot tree
if(&B_install_jail("bind",&getGlobal('BFILE',"jail.generic.hpux"))) {
my $success=0;
# add dev/null and dev/log to chroot tree
&B_mknod("", "$jail/bind/dev/null","c 3 0x000002");
&B_chmod(0666,"$jail/bind/dev/null");
&B_System(&getGlobal('BIN','mkfifo') . " -p -m 0666 " . $jail . "/bind/dev/log",
&getGlobal('BIN','rm') . " -f " . $jail . "/bind/dev/log\n" .
&getGlobal('BIN',"echo") . " \"Your DNS is not running outside of it's\\n" .
"chroot jail. You must manually migrate your named server\\n" .
"back to your Named server's default defined location(s).\\n".
"After you have completed this, feel free to remove the jail directories\\n" .
"from your machine. Be sure to reset NAMED_ARGS to equal \\\"-u daemon\\\"\\n" .
"in /etc/rc.config.d/namesvrs and then restart the daemon using the init\\n" .
"scripts. Your bind jail directory is located in\\n" .
&getGlobal('BDIR',"jail") . "\\n\" >> " . &getGlobal('BFILE',"TOUNDO"));
if(-e &getGlobal('BIN',"named-xfer")){
# install bind 8 specific files and directories.
&ActionLog("Bind 8 chroot directory setup\n");
if (&B_install_jail("bind", &getGlobal('BFILE',"jail.bind.hpux"))){
$success=1;
}
} elsif(-e &getGlobal('FILE',"named")){
# install bind 9 specific files and directories.
&ActionLog("Bind 9 chroot directory setup\n");
if(&B_install_jail("bind",&getGlobal('BFILE',"jail.bind9.hpux"))){
$success=1;
}
} else {
&ErrorLog("Bind does not appear to be on this system; no action was taken.\n");
}
if ($success) {
&B_System(&getGlobal('BIN',"cat") . " " .&getGlobal('FILE',"group") . " | " .
&getGlobal('BIN',"grep") . " named > $jail/bind/etc/group", "");
&B_chmod(0444, "$jail/bind/etc/group");
&B_chown("bin", "$jail/bind/etc/group");
&B_chgrp("bin", "$jail/bind/etc/group");
my $ch_rc = &getGlobal('BIN',"ch_rc");
my $initscript = &getGlobal('FILE',"chkconfig_named");
my $syslogd = &getGlobal('BIN',"syslogd");
#--80 chars wide----------------------------------------------------------------
&B_TODO("Chroot'ed Bind:\n" .
"Bastille has created a simple \"named\" directory structure in\n" .
"$jail/bind/\n\n" .
"You need to take the following steps to configure your name server\n" .
"to run without root privileges in a chroot jail:\n\n");
if ($extrasteps==1) {
&B_TODO("First, there were errors recorded in the error log which you will \n" .
"need to resolve. Depending on the severity of the errors, you may \n" .
"or may not be able to continue with the following steps. The most\n" .
"likely error is that a \"named\" user or group already exists, in which\n" .
"case the following steps should work just fine and \"named\" will run as\n" .
"that user.\n\n");
}
my $pidfile = &getGlobal('FILE', "named.pid");
&B_TODO("1: Stop the currently running \"named\" process using the system\'s\n" .
" init script for \"named\" \n\n" .
" type_this> $initscript stop\n\n" .
" and remove all \"/var/run/named.*\" files if they exist.\n\n" .
" type_this> rm -r /var/run/named.*\n\n" .
"2: Next, move all of the configuration files that the current \n" .
" \"named\" implementation requires from their current locations into\n" .
" the equivalent place in the jail structure. This is at least a\n" .
" \"named.conf\" file. If there is a directory path specified in the\n" .
" options section of the \"named.conf\", that path must be made as well\n" .
" as all of the files that are referenced from that directory. Remember\n" .
" that any files owned by the named user can be modified if an attacker\n" .
" breaks into bind as the \"named\" user.\n\n" .
"3: Instruct the \"named\" init script to chroot into the new environment:\n\n" .
" type_this> $ch_rc" . " -a -p NAMED_ARGS=\"-u named -t $jail/bind\"\n\n".
"4: Start named in its chroot jail using the named init script\n\n" .
" type_this> $initscript start\n");
} else {
&ErrorLog("Error trying to install the chroot bind jail.\n");
}
}
} else {
my $home_dns="/home/dns";
if (( not ( -d "${GLOBAL_PREFIX}$home_dns" ) ) and (($GLOBAL_DISTRO =~ /^RH/) or ($GLOBAL_DISTRO =~ /^MN/) )) {
# We place BIND in a chroot'd environment, following the
# instructions in SANS Step by Step 4.3.3
my $user ="";
my $group = "";
my $gid = "";
#
# Create the dns user, if one doesn't yet exist
#
# Look for a DNS user already on the operating system
if (open PASSWD,"/etc/passwd") {
my @lines = <PASSWD>;
close PASSWD;
chomp @lines;
foreach $name ( 'dns','named' ) {
if (grep /^$name:/,@lines) {
$user = $name;
}
}
}
if ($user) {
$home_dns = (getpwnam($user))[7];
}
else {
$home_dns = '/home/dns';
}
# Make the dns chroot directory
&B_create_dir ( $home_dns );
# Look for a DNS group already on the operating system
if (open PASSWD,"/etc/group") {
my @lines = <PASSWD>;
close PASSWD;
chomp @lines;
foreach $name ( 'dns','named' ) {
if (grep /^$name:/,@lines) {
$group = $name;
$gid = getgrnam($name);
}
}
}
# Create whatever users or groups are necessary
unless ($group) {
$gid = '53';
&B_append_line ("/etc/group",":53:","dns:x:53:\n");
$group = 'dns';
}
unless ($user) {
&B_append_line ("/etc/passwd",":$gid:","dns:x:53:$gid::$home_dns:/bin/false\n");
&B_append_line("/etc/shadow","^dns:","dns:*:11089:0:99999:7:::\n");
$user = 'dns';
}
# Populate the dns chroot directory
&B_create_dir ("$home_dns");
&B_create_dir ("$home_dns/etc");
&B_chmod (0755,"$home_dns/etc");
&B_create_dir ("$home_dns/lib");
&B_chmod (0755,"$home_dns/lib");
&B_create_dir ("$home_dns/dev");
&B_chmod (0755,"$home_dns/dev");
&B_create_dir ("$home_dns/usr");
&B_chmod (0755,"$home_dns/usr");
&B_create_dir ("$home_dns/usr/sbin");
&B_chmod (0755,"$home_dns/usr/sbin");
&B_create_dir ("$home_dns/var");
&B_chmod (0755,"$home_dns/var");
&B_create_dir ("$home_dns/var/named");
&B_chmod (0755,"$home_dns/var/named");
&B_create_dir ("$home_dns/var/run");
&B_chmod (0755,"$home_dns/var/run");
&B_create_dir ("$home_dns/var/run/named");
&B_chmod (0755,"$home_dns/var/run/named");
unless ($GLOBAL_LOGONLY) {
&B_mknod(" -m 666 ","$home_dns/dev/null"," c 1 3");
&B_cp("/etc/named.conf","$home_dns/etc/named.conf");
# Should we tell them to move their name logs over?
&B_cp("/var/named/named.ca","$home_dns/var/named/named.ca");
&B_cp("/var/named/named.local","$home_dns/var/named/named.local");
my $command=&getGlobal('BIN',"chown");
`$command -R $user.$user ${GLOBAL_PREFIX}$home_dns/var/named $home_dns/var/run $home_dns/var/run/named`;
&B_cp("/usr/sbin/named","$home_dns/usr/sbin/named");
&B_chmod(0755,"$home_dns/usr/sbin/named");
# Don't delete named -- let it get loaded from /usr/sbin, but
# find data files in the chroot directory. We'll still put
# a copy of the binary in the chroot directory so the named
# binary can be reloaded from there if necessary.
#
#&B_delete_file("/usr/sbin/named");
my $namedxfer = &getGlobal('BIN',"named-xfer");
if (-e $namedxfer ) {
&B_cp($namedxfer,"$home_dns" . $namedxfer);
&B_chmod(0755,"$home_dns" . $namedxfer);
}
&B_cp("/lib/libc.so.6","$home_dns/lib/libc.so.6");
&B_cp("/lib/ld-linux.so.2","$home_dns/lib/ld-linux.so.2");
}
# named communicates normally with syslog via the device /dev/log,
# which isn't accessible from the chroot'd environment. We set
# syslog to create and listen to a specific device just for bind.
&B_replace_line("/etc/rc.d/init.d/syslog",'daemon syslogd -m 0\s*\$',"daemon syslogd -m 0 -a $home_dns/dev/log\n");
&B_replace_line("/etc/rc.d/init.d/syslog",'daemon syslogd $SYSLOGD_OPTIONS\s*\$',"daemon syslogd \$SYSLOGD_OPTIONS -a $home_dns/dev/log\n");
# Modify named's init script to use the chroot environment
my $bind8=1;
if ($GLOBAL_DISTRO =~ /MN(\d+\.\d+)/) {
if ($1 >= 8.0) {
$bind8=0;
}
}
elsif ($GLOBAL_DISTRO =~ /RH(\d+\.\d+)/) {
if ($1 >= 7.1) {
$bind8=0;
}
}
if ( $bind8 ) {
&B_replace_line("/etc/rc.d/init.d/named",'^\s*daemon\s+named',"daemon named -u $user -g $group -t $home_dns\n");
}
else {
# Mandrake 8.0 and later, along with Red Hat 7.1 and later, use BIND 9, which deprecated the -g option.
# Nicely, all of these run as an alternate user already.
if ($GLOBAL_DISTRO =~ /MN/) {
&B_replace_line("/etc/rc.d/init.d/named",'^\s*daemon\s+named',"daemon named -u $user -t $home_dns\n");
}
elsif ($GLOBAL_DISTRO =~ /RH/) {
&B_append_line('/etc/sysconfig/named','^\s*ROOTDIR\s*\=\s*',"ROOTDIR=$home_dns\n");
}
}
}
else {
# We only do this to Red Hat and Mandrake boxes for now, because
# we'd have to find all the libraries and modify startup files
# and this can just be totally difficult to automate when you
# don't know the target...
&ErrorLog("Couldn't chroot named! Not on a Red Hat / Mandrake box or $home_dns already exists.\n");
}
}
}
}
sub DeactivateNamed {
if (&getGlobalConfig("DNS","namedoff") eq "Y") {
&ActionLog("# sub DeactivateNamed\n");
# Deactivate BIND unless it is being used.
&B_chkconfig_off ("named");
}
}
1;
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