--- loncom/lond	2010/03/15 05:09:59	1.438
+++ loncom/lond	2010/04/12 19:15:57	1.439
@@ -2,7 +2,7 @@
 # The LearningOnline Network
 # lond "LON Daemon" Server (port "LOND" 5663)
 #
-# $Id: lond,v 1.438 2010/03/15 05:09:59 raeburn Exp $
+# $Id: lond,v 1.439 2010/04/12 19:15:57 raeburn Exp $
 #
 # Copyright Michigan State University Board of Trustees
 #
@@ -42,7 +42,6 @@ use Crypt::IDEA;
 use LWP::UserAgent();
 use Digest::MD5 qw(md5_hex);
 use GDBM_File;
-use Authen::Krb4;
 use Authen::Krb5;
 use localauth;
 use localenroll;
@@ -59,7 +58,7 @@ my $DEBUG = 0;		       # Non zero to ena
 my $status='';
 my $lastlog='';
 
-my $VERSION='$Revision: 1.438 $'; #' stupid emacs
+my $VERSION='$Revision: 1.439 $'; #' stupid emacs
 my $remoteVERSION;
 my $currenthostid="default";
 my $currentdomainid;
@@ -6708,54 +6707,24 @@ sub validate_user {
 	    } else {
 		$validated = 0;
 	    }
-	}
-	elsif ($howpwd eq "krb4") { # user is in kerberos 4 auth. domain.
-	    if(! ($password =~ /$null/) ) {
-		my $k4error = &Authen::Krb4::get_pw_in_tkt($user,
-							   "",
-							   $contentpwd,,
-							   'krbtgt',
-							   $contentpwd,
-							   1,
-							   $password);
-		if(!$k4error) {
-		    $validated = 1;
-		} else {
-		    $validated = 0;
-		    &logthis('krb4: '.$user.', '.$contentpwd.', '.
-			     &Authen::Krb4::get_err_txt($Authen::Krb4::error));
-		}
-	    } else {
-		$validated = 0; # Password has a match with null.
-	    }
+	} elsif ($howpwd eq "krb4") { # user is in kerberos 4 auth. domain.
+            my $checkwithkrb5 = 0;
+            if ($dist =~/^fedora(\d+)$/) {
+                if ($1 > 11) {
+                    $checkwithkrb5 = 1;
+                }
+            } elsif ($dist =~ /^suse([\d.]+)$/) {
+                if ($1 > 11.1) {
+                    $checkwithkrb5 = 1; 
+                }
+            }
+            if ($checkwithkrb5) {
+                $validated = &krb5_authen($password,$null,$user,$contentpwd);
+            } else {
+                $validated = &krb4_authen($password,$null,$user,$contentpwd);
+            }
 	} elsif ($howpwd eq "krb5") { # User is in kerberos 5 auth. domain.
-	    if(!($password =~ /$null/)) { # Null password not allowed.
-		my $krbclient = &Authen::Krb5::parse_name($user.'@'
-							  .$contentpwd);
-		my $krbservice = "krbtgt/".$contentpwd."\@".$contentpwd;
-		my $krbserver  = &Authen::Krb5::parse_name($krbservice);
-		my $credentials= &Authen::Krb5::cc_default();
-		$credentials->initialize(&Authen::Krb5::parse_name($user.'@'
-                                                                 .$contentpwd));
-                my $krbreturn;
-                if (exists(&Authen::Krb5::get_init_creds_password)) {
-                    $krbreturn = 
-                        &Authen::Krb5::get_init_creds_password($krbclient,$password,
-                                                               $krbservice);
-                    $validated = (ref($krbreturn) eq 'Authen::Krb5::Creds');
-                } else {
-		    $krbreturn  = 
-                        &Authen::Krb5::get_in_tkt_with_password($krbclient,$krbserver,
-		 						$password,$credentials);
-		    $validated = ($krbreturn == 1);
-                }
-		if (!$validated) {
-		    &logthis('krb5: '.$user.', '.$contentpwd.', '.
-			     &Authen::Krb5::error());
-		}
-	    } else {
-		$validated = 0;
-	    }
+            $validated = &krb5_authen($password,$null,$user,$contentpwd);
 	} elsif ($howpwd eq "localauth") { 
 	    #  Authenticate via installation specific authentcation method:
 	    $validated = &localauth::localauth($user, 
@@ -6786,6 +6755,65 @@ sub validate_user {
     return $validated;
 }
 
+sub krb4_authen {
+    my ($password,$null,$user,$contentpwd) = @_;
+    my $validated = 0;
+    if (!($password =~ /$null/) ) {  # Null password not allowed.
+        eval {
+            require Authen::Krb4;
+        };
+        if (!$@) {
+            my $k4error = &Authen::Krb4::get_pw_in_tkt($user,
+                                                       "",
+                                                       $contentpwd,,
+                                                       'krbtgt',
+                                                       $contentpwd,
+                                                       1,
+                                                       $password);
+            if(!$k4error) {
+                $validated = 1;
+            } else {
+                $validated = 0;
+                &logthis('krb4: '.$user.', '.$contentpwd.', '.
+                          &Authen::Krb4::get_err_txt($Authen::Krb4::error));
+            }
+        } else {
+            $validated = krb5_authen($password,$null,$user,$contentpwd);
+        }
+    }
+    return $validated;
+}
+
+sub krb5_authen {
+    my ($password,$null,$user,$contentpwd) = @_;
+    my $validated = 0;
+    if(!($password =~ /$null/)) { # Null password not allowed.
+        my $krbclient = &Authen::Krb5::parse_name($user.'@'
+                                                  .$contentpwd);
+        my $krbservice = "krbtgt/".$contentpwd."\@".$contentpwd;
+        my $krbserver  = &Authen::Krb5::parse_name($krbservice);
+        my $credentials= &Authen::Krb5::cc_default();
+        $credentials->initialize(&Authen::Krb5::parse_name($user.'@'
+                                                            .$contentpwd));
+        my $krbreturn;
+        if (exists(&Authen::Krb5::get_init_creds_password)) {
+            $krbreturn =
+                &Authen::Krb5::get_init_creds_password($krbclient,$password,
+                                                          $krbservice);
+            $validated = (ref($krbreturn) eq 'Authen::Krb5::Creds');
+        } else {
+            $krbreturn  =
+                &Authen::Krb5::get_in_tkt_with_password($krbclient,$krbserver,
+                                                         $password,$credentials);
+            $validated = ($krbreturn == 1);
+        }
+        if (!$validated) {
+            &logthis('krb5: '.$user.', '.$contentpwd.', '.
+                     &Authen::Krb5::error());
+        }
+    }
+    return $validated;
+}
 
 sub addline {
     my ($fname,$hostid,$ip,$newline)=@_;