-Add a concept for host-authentication credential retrieval with encryption, to be controlled by policy table for security tuning

git-svn-id: https://svn.code.sf.net/p/xcat/code/xcat-core/trunk@1066 8638fb3e-16cb-4fca-ae20-7b5d299a9bcd

xCAT-server-2.0/lib/xcat/plugins/credentials.pm

@@ -0,0 +1,150 @@
+# 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 xCAT::Table;
+use Data::Dumper;
+use xCAT::NodeRange;
+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 ($client) { #Not able to do host authentication, abort
+       return;
+    }
+    unless ($request->{'callback_port'} and $request->{'callback_port'}->[0] and $request->{'callback_port'}->[0] < 1024) {
+       print "WT\n";
+       return;
+    }
+    unless (ok_with_node($client,$request->{'callback_port'}->[0])) {
+       return;
+    }
+
+    my @params_to_return = @{$request->{arg}};
+    $rsp->{data}=[];
+    my $tmpfile;
+    my @filecontent;
+    my $retdata;
+    foreach (@params_to_return) {
+       if (/ssh_root_key/) { 
+          unless (-r "/root/.ssh/id_rsa") {
+            push @{$rsp->{'error'}},"Unable to read root's private ssh key";
+            next;
+          }
+          open($tmpfile,"/root/.ssh/id_rsa");
+          @filecontent=<$tmpfile>;
+          close($tmpfile);
+          $retdata = join('',@filecontent);
+          push @{$rsp->{'data'}},{content=>[$retdata],desc=>[$_]};
+          $retdata="";
+          @filecontent=();
+       }
+    }
+    xCAT::MsgUtils->message("D", $rsp, $callback, 0);
+    return;
+}
+
+sub ok_with_node {
+   my $node = shift;
+   #Here we connect to the node on a privileged port (in the clear) 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
+   my $select = new IO::Select;
+   sleep 0.5; # gawk script race condition might exist, try to lose just in case
+   my $sock = new IO::Socket::INET(PeerAddr=>$node,
+                                     Proto => "tcp",
+                                     PeerPort => shift);
+   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;
+   }
+   return 0;
+}
+                                    
+   
+1;