# IBM(c) 2007 EPL license http://www.eclipse.org/legal/epl-v10.html #------------------------------------------------------- =head1 Plugin to handle credentials with good old fashioned priveleged port/host based authentication May also include xCAT state-sensitive denial/allow Also controlled by policy table (SECURITY: must document how to harden and make more convenient through policy table). This sounds horrible and most of the time it would be. However, when dealing with unattended installs, it is better than nothing. Apache does not appear to be able to give credence to privileged ports vs. non-privileged ports on the client, so simple nfs-style authentication is not possible. The problem with more secure methods and unattended installs is that all rely upon the client to have a blessed credential, and giving that credential or blessing a credential I can't think of a way to feasibly do unattended truly securely, so here we try to mitigate the exposure and implement nfs-like security (with the plus of encryption, hopefully) Supported command: getcredentials =cut #------------------------------------------------------- package xCAT_plugin::credentials; use strict; use xCAT::Table; use Data::Dumper; use xCAT::NodeRange; use xCAT::Zone; use IO::Socket::INET; use Time::HiRes qw(sleep); use xCAT::Utils; use xCAT::MsgUtils; use Getopt::Long; #------------------------------------------------------- =head3 handled_commands Return list of commands handled by this plugin =cut #------------------------------------------------------- sub handled_commands { return {getcredentials => "credentials" }; } #------------------------------------------------------- =head3 process_request Process the command =cut #------------------------------------------------------- my $callback; sub process_request { my $request = shift; $callback = shift; my $command = $request->{command}->[0]; my $args = $request->{arg}; my $envs = $request->{env}; my $client; #Because clients may be stuck with stunnel, we cannot presume they #can explicitly bind to a low port number as a client #unless ($request and $request->{'_xcat_clientport'} and $request->{'_xcat_clientport'}->[0] and $request->{'_xcat_clientport'}->[0] < 1000) { # print Dumper($request); # return; #only accept requests from privileged ports #} if ($request->{'_xcat_clienthost'}) { $client = $request->{'_xcat_clienthost'}->[0]; } my $rsp; # do your processing here # return info if ($client) { ($client) = noderange($client) }; unless ($client) { #Not able to do host authentication, abort return; } my $credcheck; if ($request->{'callback_port'} and $request->{'callback_port'}->[0] and $request->{'callback_port'}->[0] < 1024) { $credcheck=[0,$request->{'callback_port'}->[0]]; } elsif ($request->{'callback_https_port'} and $request->{'callback_https_port'}->[0] and $request->{'callback_https_port'}->[0] < 1024) { $credcheck=[1,$request->{'callback_https_port'}->[0]]; } else { return; } unless (ok_with_node($client,$credcheck)) { return; } my @params_to_return = @{$request->{arg}}; $rsp->{data}=[]; my $tmpfile; my @filecontent; my $retdata; my $tfilename; my $root; if (xCAT::Utils->isAIX()) { $root = ""; } else { $root = "/root"; } foreach my $parm (@params_to_return) { # if paramter is ssh_root_key or ssh_root_pub_key then # we need to see if a zonename is attached # it comes in as ssh_root_key:zonename # if zonename then we need to read the keys from the zone table sshkeydir attribute my $errorfindingkeys=0; my $foundkeys=0; my $sshrootkeydir="$root/.ssh"; # old default if ((($parm =~ /^ssh_root_key/) || ($parm =~ /^ssh_root_pub_key/)) && ($foundkeys==0)){ my ($rootkeyparm,$zonename) = split(/:/,$parm); if ($zonename) { $parm=$rootkeyparm; # take the zone off `logger -t xCAT -p local4.info "credentials: The node is asking for zone:$zonename sshkeys ."`; $sshrootkeydir = xCAT::Zone->getzonekeydir($zonename); if ($sshrootkeydir == 1) { # error return `logger -t xCAT -p local4.info "credentials: The node is asking for zone:$zonename sshkeys and the $zonename is not defined."`; } else { $foundkeys=1; # don't want to read the zone data twice } } } if ($parm =~ /ssh_root_key/) { unless (-r "$sshrootkeydir/id_rsa") { push @{$rsp->{'error'}},"Unable to read root's private ssh key"; `logger -t xCAT -p local4.info "credentials: Unable to read root's private ssh key"` ; next; } `logger -t xCAT -p local4.info "credentials: sending $parm"` ; $tfilename = "$sshrootkeydir/id_rsa"; `logger -t xCAT -p local4.info "credentials: The ssh root private key is in $tfilename."`; } elsif ($parm =~ /ssh_root_pub_key/) { unless (-r "$sshrootkeydir/id_rsa.pub") { push @{$rsp->{'error'}},"Unable to read root's public ssh key"; `logger -t xCAT -p local4.info "credentials: Unable to read root's public ssh key"` ; next; } `logger -t xCAT -p local4.info "credentials: sending $parm"` ; $tfilename = "$sshrootkeydir/id_rsa.pub"; `logger -t xCAT -p local4.info "credentials: The ssh root public key is in $tfilename."`; } elsif ($parm =~ /xcat_server_cred/) { unless (-r "/etc/xcat/cert/server-cred.pem") { push @{$rsp->{'error'}},"Unable to read xcat_server_cred"; `logger -t xCAT -p local4.info "credentials: Unable to read xcat_server_cred"` ; next; } `logger -t xCAT -p local4.info "credentials: sending $parm"` ; $tfilename = "/etc/xcat/cert/server-cred.pem"; } elsif (($parm =~ /xcat_client_cred/) or ($parm =~ /xcat_root_cred/)) { unless (-r "$root/.xcat/client-cred.pem") { push @{$rsp->{'error'}},"Unable to read xcat_client_cred or xcat_root_cred"; `logger -t xCAT -p local4.info "credentials: Unable to read xcat_client_cred or xcat_root_cred"` ; next; } `logger -t xCAT -p local4.info "credentials: sending $parm"` ; $tfilename = "$root/.xcat/client-cred.pem"; } elsif ($parm =~ /ssh_dsa_hostkey/) { `logger -t xCAT -p local4.info "credentials: sending $parm"` ; if (-r "/etc/xcat/hostkeys/$client/ssh_host_dsa_key") { $tfilename="/etc/xcat/hostkeys/$client/ssh_host_dsa_key"; } elsif (-r "/etc/xcat/hostkeys/ssh_host_dsa_key") { $tfilename="/etc/xcat/hostkeys/ssh_host_dsa_key"; } else { push @{$rsp->{'error'}},"Unable to read private DSA key from /etc/xcat/hostkeys"; `logger -t xCAT -p local4.info "credentials: Unable to read private DSA key"` ; next; } } elsif ($parm =~ /ssh_rsa_hostkey/) { `logger -t xCAT -p local4.info "credentials: sending $parm"` ; if (-r "/etc/xcat/hostkeys/$client/ssh_host_rsa_key") { $tfilename="/etc/xcat/hostkeys/$client/ssh_host_rsa_key"; } elsif (-r "/etc/xcat/hostkeys/ssh_host_rsa_key") { $tfilename="/etc/xcat/hostkeys/ssh_host_rsa_key"; } else { push @{$rsp->{'error'}},"Unable to read private RSA key from /etc/xcat/hostkeys"; `logger -t xCAT -p local4.info "credentials: Unable to read private RSA key"` ; next; } } elsif ($parm =~ /xcat_cfgloc/) { `logger -t xCAT -p local4.info "credentials: sending $parm"` ; unless (-r "/etc/xcat/cfgloc") { push @{$rsp->{'error'}},"Unable to read /etc/xcat/cfgloc "; `logger -t xCAT -p local4.info "credentials: Unable to read /etc/xcat/cfgloc"` ; next; } $tfilename = "/etc/xcat/cfgloc"; } elsif ($parm =~ /krb5_keytab/) { #TODO: MUST RELAY TO MASTER `logger -t xCAT -p local4.info "credentials: sending $parm"` ; my $princsuffix=$request->{'_xcat_clientfqdn'}->[0]; $ENV{KRB5CCNAME}="/tmp/xcat/krb5cc_xcat_$$"; system('kinit -S kadmin/admin -k -t /etc/xcat/krb5_pass xcat/admin'); system("kadmin -p xcat/admin -c /tmp/xcat/krb5cc_xcat_$$ -q 'delprinc -force host/$princsuffix'"); system("kadmin -p xcat/admin -c /tmp/xcat/krb5cc_xcat_$$ -q 'delprinc -force nfs/$princsuffix'"); system("kadmin -p xcat/admin -c /tmp/xcat/krb5cc_xcat_$$ -q 'addprinc -randkey host/$princsuffix'"); system("kadmin -p xcat/admin -c /tmp/xcat/krb5cc_xcat_$$ -q 'addprinc -randkey nfs/$princsuffix'"); unlink "/tmp/xcat/keytab.$$"; system("kadmin -p xcat/admin -c /tmp/xcat/krb5cc_xcat_$$ -q 'ktadd -k /tmp/xcat/keytab.$$ nfs/$princsuffix'"); system("kadmin -p xcat/admin -c /tmp/xcat/krb5cc_xcat_$$ -q 'ktadd -k /tmp/xcat/keytab.$$ host/$princsuffix'"); system("kdestroy -c /tmp/xcat/krb5cc_xcat_$$"); unlink("/tmp/xcat/krb5cc_xcat_$$"); my $keytab; open($keytab, "/tmp/xcat/keytab.$$"); my $tabdata="\n"; my $buf; require MIME::Base64; while (read($keytab,$buf,1140)) { $tabdata.=MIME::Base64::encode_base64($buf); } push @{$rsp->{'data'}},{content=>[$tabdata],desc=>[$parm]}; unlink "/tmp/xcat/keytab.$$"; next; } elsif ($parm =~ /x509cert/) { `logger -t xCAT -p local4.info "credentials: sending $parm"` ; my $csr = $request->{'csr'}->[0]; my $csrfile; my $oldumask = umask 0077; if (-e "/tmp/xcat/client.csr.$$") { unlink "/tmp/xcat/client.csr.$$"; } open($csrfile,">","/tmp/xcat/client.csr.$$"); unless($csrfile) { next; } my @statdat = stat $csrfile; while ($statdat[4] != 0 or $statdat[2] & 020 or $statdat[2] & 002) { #try to be paranoid, root better own the file, and it better not be writable by anyone but owner #this means to assure the filehandle is not write-accessible to others who may insert their malicious CSR close($csrfile); unlink("/tmp/xcat/client.csr.$$"); open($csrfile,">","/tmp/xcat/client.csr.$$"); @statdat = stat $csrfile; } print $csrfile $csr; close($csrfile); #ok, at this point, we can verify that the subject is one we wouldn't mind signing... my $subject=`openssl req -in /tmp/xcat/client.csr.$$ -subject -noout`; chomp($subject); unless ($subject =~ /CN=$client\z/) { unlink("/tmp/xcat/client.csr.$$"); next; } unlink "/tmp/xcat/client.cert.$$"; open($csrfile,">","/tmp/xcat/client.cert.$$"); @statdat = stat $csrfile; while ($statdat[4] != 0 or $statdat[2] & 020 or $statdat[2] & 002) { #try to be paranoid, root better own the file, and it better not be writable by anyone but owner #this prevents an attacker from predicting pid and pre-setting up a file that they can corrupt for DoS close($csrfile); unlink("/tmp/xcat/client.csr.$$"); open($csrfile,">","/tmp/xcat/client.csr.$$"); @statdat = stat $csrfile; } close($csrfile); open($csrfile,"<","/etc/xcat/ca/index"); my @caindex = <$csrfile>; close($csrfile); foreach (@caindex) { chomp; my ($type, $expiry, $revoke, $serial, $fname, $subject) = split /\t/; if ($type eq 'V' and $subject =~ /CN=$client\z/) { #we already have a valid certificate, new request replaces it, revoke old print "The time of replacing is at hand for $client\n"; system("openssl ca -config /etc/xcat/ca/openssl.cnf -revoke /etc/xcat/ca/certs/$serial.pem"); } } my $rc = system("openssl ca -config /etc/xcat/ca/openssl.cnf -in /tmp/xcat/client.csr.$$ -out /tmp/xcat/client.cert.$$ -batch"); unlink("/tmp/xcat/client.csr.$$"); umask ($oldumask); if ($rc) { next; } open ($csrfile,"<","/tmp/xcat/client.cert.$$"); my @certdata = <$csrfile>; close($csrfile); unlink "/tmp/xcat/client.cert.$$"; my $certcontents = join('',@certdata); push @{$rsp->{'data'}},{content=>[$certcontents],desc=>[$parm]}; } else { next; } #check if the file exists or not if (defined $tfilename && -r $tfilename) { open($tmpfile,$tfilename); @filecontent=<$tmpfile>; close($tmpfile); $retdata = "\n".join('',@filecontent); push @{$rsp->{'data'}},{content=>[$retdata],desc=>[$parm]}; $retdata=""; @filecontent=(); } } if (defined $rsp->{data}->[0]) { #if we got the data from the file, send the data message to the client xCAT::MsgUtils->message("D", $rsp, $callback, 0); return; }else { #if the file doesn't exist, send the error message to the client delete $rsp->{'data'}; xCAT::MsgUtils->message("E", $rsp, $callback, 0); } return; } sub ok_with_node { my $node = shift; #Here we connect to the node on a privileged port and ask the #node if it just asked us for credential. It's convoluted, but it is #a convenient way to see if root on the ip has approved requests for #credential retrieval. Given the nature of the situation, it is only ok #to assent to such requests before users can log in. During postscripts #stage in stateful nodes and during the rc scripts of stateless boot #This is about equivalent to host-based authentication in Unix world #Generally good to move on to more robust mechanisms, but in an unattended context #this proves difficult to do robustly. #one TODO would be a secure mode where we make use of TPM modules to enhance in some way my $select = new IO::Select; #sleep 0.5; # gawk script race condition might exist, try to lose just in case my $parms = shift; my $method=$parms->[0]; my $port = $parms->[1]; if ($method == 0) { #PLAIN my $sock = new IO::Socket::INET(PeerAddr=>$node, Proto => "tcp", PeerPort => $port); my $rsp; unless ($sock) {return 0}; $select->add($sock); print $sock "CREDOKBYYOU?\n"; unless ($select->can_read(5)) { #wait for data for up to five seconds return 0; } my $response = <$sock>; chomp($response); if ($response eq "CREDOKBYME") { return 1; } } elsif ($method == 1) { #HTTPS use LWP; use HTTP::Request::Common; my $browser = LWP::UserAgent->new(); $browser->timeout(10); $SIG{ALRM} = sub {}; #just need to interrupt the system call alarm(10); my $response = $browser->request(GET "https://$node:$port/"); alarm(0); if ($response->is_success and $response->{'_content'} =~ /Ciphers supported in s_server binary/) { #We are looking for openssl s_server running with -http, not settling for just any https response return 1; } } return 0;#if here, something wrong happened, return false } 1;