--- loncom/auth/lonauth.pm	2014/12/05 12:03:20	1.136
+++ loncom/auth/lonauth.pm	2021/10/26 15:10:34	1.167
@@ -1,7 +1,7 @@
 # The LearningOnline Network
 # User Authentication Module
 #
-# $Id: lonauth.pm,v 1.136 2014/12/05 12:03:20 kruse Exp $
+# $Id: lonauth.pm,v 1.167 2021/10/26 15:10:34 raeburn Exp $
 #
 # Copyright Michigan State University Board of Trustees
 #
@@ -29,24 +29,24 @@
 package Apache::lonauth;
 
 use strict;
-use LONCAPA;
+use LONCAPA qw(:DEFAULT :match);
 use Apache::Constants qw(:common);
 use CGI qw(:standard);
-use DynaLoader; # for Crypt::DES version
-use Crypt::DES;
 use Apache::loncommon();
 use Apache::lonnet;
 use Apache::lonmenu();
 use Apache::createaccount;
+use Apache::ltiauth;
 use Fcntl qw(:flock);
 use Apache::lonlocal;
 use Apache::File();
 use HTML::Entities;
+use Digest::MD5;
  
 # ------------------------------------------------------------ Successful login
 sub success {
     my ($r, $username, $domain, $authhost, $lowerurl, $extra_env,
-	$form) = @_;
+	$form,$skipcritical,$cid) = @_;
 
 # ------------------------------------------------------------ Get cookie ready
     my $cookie =
@@ -60,23 +60,73 @@ sub success {
 
 # -------------------------------------------------------------------- Log this
 
+    my $ip = &Apache::lonnet::get_requestor_ip();
     &Apache::lonnet::log($domain,$username,$authhost,
-                         "Login $ENV{'REMOTE_ADDR'}");
+                         "Login $ip");
 
 # ------------------------------------------------- Check for critical messages
 
-    my @what=&Apache::lonnet::dump('critical',$domain,$username);
-    if ($what[0]) {
-	if (($what[0] ne 'con_lost') && ($what[0]!~/^error\:/)) {
-	    $lowerurl='/adm/email?critical=display';
+    unless ($skipcritical) {
+        my @what=&Apache::lonnet::dump('critical',$domain,$username);
+        if ($what[0]) {
+	    if (($what[0] ne 'con_lost') && ($what[0]!~/^error\:/)) {
+	        $lowerurl='/adm/email?critical=display';
+            }
         }
     }
 
-# ------------------------------------------------------------ Get cookie ready
-    $cookie="lonID=$cookie; path=/";
+# ----------------------------------------------------------- Get cookies ready
+    my ($securecookie,$defaultcookie);
+    my $ssl = $r->subprocess_env('https');
+    if ($ssl) {
+        $securecookie="lonSID=$cookie; path=/; HttpOnly; secure";
+        my $lonidsdir=$r->dir_config('lonIDsDir');
+        if (($lonidsdir) && (-e "$lonidsdir/$cookie.id")) {
+            my $linkname=substr(Digest::MD5::md5_hex(Digest::MD5::md5_hex(time(). {}. rand(). $$)), 0, 32).'_linked';
+            if (-e "$lonidsdir/$linkname.id") {
+                unlink("$lonidsdir/$linkname.id");
+            }
+            my $made_symlink = eval { symlink("$lonidsdir/$cookie.id",
+                                              "$lonidsdir/$linkname.id"); 1 };
+            if ($made_symlink) {
+                $defaultcookie = "lonLinkID=$linkname; path=/; HttpOnly;";
+                &Apache::lonnet::appenv({'user.linkedenv' => $linkname});
+            }
+        }
+    } else {
+        $defaultcookie = "lonID=$cookie; path=/; HttpOnly;";
+    }
 # -------------------------------------------------------- Menu script and info
     my $destination = $lowerurl;
-
+    if ($env{'request.lti.login'}) {
+        if (($env{'request.lti.reqcrs'}) && ($env{'request.lti.reqrole'} eq 'cc')) {
+            &Apache::loncommon::content_type($r,'text/html');
+            if ($securecookie) {
+                $r->headers_out->add('Set-cookie' => $securecookie);
+            }
+            if ($defaultcookie) {
+                $r->headers_out->add('Set-cookie' => $defaultcookie);
+            }
+            $r->send_http_header;
+            if (ref($form) eq 'HASH') {
+                $form->{'lti.login'} = $env{'request.lti.login'};
+                $form->{'lti.reqcrs'} = $env{'request.lti.reqcrs'};
+                $form->{'lti.reqrole'} = $env{'request.lti.reqrole'};
+                $form->{'lti.sourcecrs'} = $env{'request.lti.sourcecrs'};
+            }
+            &Apache::ltiauth::lti_reqcrs($r,$domain,$form,$username,$domain);
+            return;
+        }
+        if ($env{'request.lti.selfenrollrole'}) {
+            if (&Apache::ltiauth::lti_enroll($username,$domain,
+                                             $env{'request.lti.selfenrollrole'}) eq 'ok') {
+                $form->{'role'} = $env{'request.lti.selfenrollrole'};
+                &Apache::lonnet::delenv('request.lti.selfenrollrole');
+            } else {
+                &Apache::ltiauth::invalid_request($r,24);
+            }
+        }
+    }
     if (defined($form->{role})) {
         my $envkey = 'user.role.'.$form->{role};
         my $now=time;
@@ -99,18 +149,26 @@ sub success {
     }
     if (defined($form->{symb})) {
         my $destsymb = $form->{symb};
+        my $encrypted;
+        if ($destsymb =~ m{^/enc/}) {
+            $encrypted = 1;
+            if ($cid) {
+                $destsymb = &Apache::lonenc::unencrypted($destsymb,$cid);
+            }
+        }
         $destination  .= ($destination =~ /\?/) ? '&' : '?';
         if ($destsymb =~ /___/) {
-            # FIXME Need to deal with encrypted symbs and urls as needed.
             my ($map,$resid,$desturl)=split(/___/,$destsymb);
-            unless ($desturl=~/^(adm|editupload|public)/) {
-                $desturl = &Apache::lonnet::clutter($desturl);
+            $desturl = &Apache::lonnet::clutter($desturl);
+            if ($encrypted) {
+                $desturl = &Apache::lonenc::encrypted($desturl,1,$cid);
+                $destsymb = $form->{symb};
             }
             $desturl = &HTML::Entities::encode($desturl,'"<>&');
             $destsymb = &HTML::Entities::encode($destsymb,'"<>&');
             $destination .= 'destinationurl='.$desturl.
                             '&destsymb='.$destsymb;
-        } else {
+        } elsif (!$encrypted) {
             $destsymb = &HTML::Entities::encode($destsymb,'"<>&');
             $destination .= 'destinationurl='.$destsymb;
         }
@@ -120,39 +178,97 @@ sub success {
         $destination .= 'source=login';
     }
 
-    my $windowinfo = Apache::lonhtmlcommon::scripttag('self.name="loncapaclient";');
-    my $header = '<meta HTTP-EQUIV="Refresh" CONTENT="0; url='.$destination.'" />';
+    my $windowname = 'loncapaclient';
+    if ($env{'request.lti.login'}) {
+        $windowname .= 'lti';
+    }
+    my $windowinfo = Apache::lonhtmlcommon::scripttag('self.name="'.$windowname.'";');
     my $brcrum = [{'href' => '',
                    'text' => 'Successful Login'},];
-    my $start_page=&Apache::loncommon::start_page('Successful Login',
-                                                  $header,
-                                                  {'bread_crumbs' => $brcrum,});
-    my $end_page  =&Apache::loncommon::end_page();
+    my $args = {'bread_crumbs' => $brcrum,};
+    unless ((defined($form->{role})) || (defined($form->{symb}))) {
+        my $update=$env{'user.update.time'};
+        if (!$update) {
+            $update = $env{'user.login.time'};
+        }
+        my %roles_in_env;
+        my $showcount = &Apache::lonroles::roles_from_env(\%roles_in_env,$update);
+        if ($showcount == 1) {
+            foreach my $rolecode (keys(%roles_in_env)) {
+                my ($cid) = ($rolecode =~ m{^\Quser.role.st./\E($match_domain/$match_courseid)(?:/|$)});
+                if ($cid) {
+                    my %coursedescription =
+                        &Apache::lonnet::coursedescription($cid,{'one_time' => '1'});
+                    if ($coursedescription{'type'} eq 'Placement') {
+                        $args->{'crstype'} = 'Placement';
+                    }
+                    last;
+                }
+            }
+        }
+    }
 
-	my $continuelink='<a href="'.$destination.'">'.&mt('Continue').'</a>';
 # ------------------------------------------------- Output for successful login
 
     &Apache::loncommon::content_type($r,'text/html');
-    $r->header_out('Set-cookie' => $cookie);
+    if ($securecookie) {
+        $r->headers_out->add('Set-cookie' => $securecookie);
+    }
+    if ($defaultcookie) {
+        $r->headers_out->add('Set-cookie' => $defaultcookie);
+    }
     $r->send_http_header;
 
-    my %lt=&Apache::lonlocal::texthash(
-				       'wel' => 'Welcome',
-				       'pro' => 'Login problems?',
-				       );
-    my $loginhelp = &loginhelpdisplay($domain);
-    if ($loginhelp) {
-        $loginhelp = '<p><a href="'.$loginhelp.'">'.$lt{'pro'}.'</a></p>';
+    my ($start_page,$js,$pagebody,$end_page);
+    if ($env{'request.lti.login'}) {
+        $args = {'only_body' => 1};
+        if ($env{'request.lti.target'} eq '') {
+            my $ltitarget = (($destination =~ /\?/) ? '&' : '?').
+                            'ltitarget=iframe';
+            $js = <<"ENDJS";
+
+<script type="text/javascript">
+// <![CDATA[
+function setLTItarget() {
+    var newloc = '$destination';
+    if (parent !== window) {
+        newloc += '$ltitarget';
     }
+    window.location.href=newloc;
+}
+// ]]>
+</script>
 
-    my $welcome = &mt('Welcome to the Learning[_1]Online[_2] Network with CAPA. Please wait while your session is being set up.','<i>','</i>'); 
+ENDJS
+            $args->{'add_entries'} = {'onload' => "javascript:setLTItarget();"};
+            $pagebody =  '<noscript><span class="LC_warning">'
+                        .&mt('Use of LON-CAPA requires Javascript to be enabled in your web browser.')
+                        .'</span></noscript>';
+        } else {
+            $args->{'redirect'} = [0,$destination,1];
+        }
+        $start_page=&Apache::loncommon::start_page('',$js,$args);
+    } else {
+        $args->{'redirect'} = [0,$destination];
+        $start_page=&Apache::loncommon::start_page('Successful Login',
+                                                   $js,$args);
+
+        my %lt=&Apache::lonlocal::texthash(
+				           'wel' => 'Welcome',
+				           'pro' => 'Login problems?',
+				          );
+        $pagebody = "<h1>$lt{'wel'}</h1>\n".
+                    &mt('Welcome to the Learning[_1]Online[_2] Network with CAPA. Please wait while your session is being set up.','<i>','</i>');
+        my $loginhelp = &loginhelpdisplay($domain);
+        if ($loginhelp) {
+            $pagebody .= '<p><a href="'.$loginhelp.'">'.$lt{'pro'}.'</a></p>';
+        }
+    }
+    $end_page = &Apache::loncommon::end_page();
     $r->print(<<ENDSUCCESS);
 $start_page
 $windowinfo
-<h1>$lt{'wel'}</h1>
-$welcome
-$loginhelp
-$continuelink
+$pagebody
 $end_page
 ENDSUCCESS
     return;
@@ -194,6 +310,26 @@ sub failed {
             $retry .= (($retry=~/\?/)?'&amp;':'?').'symb='.$symb;
         }
     }
+    if (exists($form->{firsturl})) {
+        my $firsturl = &Apache::loncommon::cleanup_html($form->{firsturl});
+        if ($firsturl ne '') {
+            $retry .= (($retry=~/\?/)?'&amp;':'?').'firsturl='.$firsturl;
+            if ($firsturl =~ m{^/tiny/$match_domain/\w+$}) {
+                unless (exists($form->{linkprot})) {
+                    if (exists($form->{linkkey})) {
+                        $retry .= 'linkkey='.$form->{linkkey};
+                    }
+                }
+            }
+        }
+    }
+    if (exists($form->{linkprot})) {
+        my $ltoken = &Apache::lonnet::tmpput({linkprot => $form->{'linkprot'}},
+                                             $r->dir_config('lonHostID'));
+        if ($ltoken) {
+            $retry .= (($retry =~ /\?/) ? '&' : '?').'ltoken='.$ltoken;
+        }
+    }
     my $end_page = &Apache::loncommon::end_page();
     &Apache::loncommon::content_type($r,'text/html');
     $r->send_http_header;
@@ -230,7 +366,6 @@ sub reroute {
 sub handler {
     my $r = shift;
     my $londocroot = $r->dir_config('lonDocRoot');
-    my $form;
 # Are we re-routing?
     if (-e "$londocroot/lon-status/reroute.txt") {
 	&reroute($r);
@@ -251,13 +386,41 @@ sub handler {
             &Apache::lonnet::transfer_profile_to_env($lonidsdir,$handle);
 	    &Apache::loncommon::content_type($r,'text/html');
 	    $r->send_http_header;
-	    my $start_page = 
+	    my $start_page =
 	        &Apache::loncommon::start_page('Already logged in');
 	    my $end_page = 
 	        &Apache::loncommon::end_page();
             my $dest = '/adm/roles';
             if ($env{'form.firsturl'} ne '') {
                 $dest = $env{'form.firsturl'};
+                if (($dest =~ m{^/tiny/$match_domain/\w+$}) && ($env{'request.course.id'})) {
+                    my $cnum = $env{'course.'.$env{'request.course.id'}.'.num'};
+                    my $cdom = $env{'course.'.$env{'request.course.id'}.'.domain'};
+                    my $symb = &Apache::loncommon::symb_from_tinyurl($dest,$cnum,$cdom);
+                    if ($symb) {
+                        my $buffer;
+                        if ($r->header_in('Content-length') > 0) {
+                            $r->read($buffer,$r->header_in('Content-length'),0);
+                        }
+                        my %form;
+                        foreach my $pair (split(/&/,$buffer)) {
+                            my ($name,$value) = split(/=/,$pair);
+                            $value =~ tr/+/ /;
+                            $value =~ s/%([a-fA-F0-9][a-fA-F0-9])/pack("C",hex($1))/eg;
+                            $form{$name}=$value;
+                        }
+                        &set_deeplink_login(%form);
+                    } else {
+                        $r->print(
+                                  $start_page
+                                 .'<p class="LC_warning">'.&mt('You are already logged in!').'</p>'
+                                 .'<p>'.&mt('Please [_1]log out[_2] first, and then try your access again',
+                                            '<a href="/adm/logout">','</a>')
+                                 .'</p>'
+                                 .$end_page);
+                        return OK;
+                    }
+                }
             }
             $r->print(
                $start_page
@@ -294,10 +457,11 @@ sub handler {
 
 # split user logging in and "su"-user
 
-    ($form{'uname'},$form{'suname'})=split(/\:/,$form{'uname'});
+    ($form{'uname'},$form{'suname'},$form{'sudom'})=split(/\:/,$form{'uname'});
     $form{'uname'} = &LONCAPA::clean_username($form{'uname'});
     $form{'suname'}= &LONCAPA::clean_username($form{'suname'});
-    $form{'udom'}  = &LONCAPA::clean_domain(  $form{'udom'});
+    $form{'udom'}  = &LONCAPA::clean_domain($form{'udom'});
+    $form{'sudom'} = &LONCAPA::clean_domain($form{'sudom'});
 
     my $role   = $r->dir_config('lonRole');
     my $domain = $r->dir_config('lonDefDomain');
@@ -309,12 +473,6 @@ sub handler {
     my $tmpinfo=Apache::lonnet::reply('tmpget:'.$form{'logtoken'},
                                       $form{'serverid'});
 
-    my %sessiondata;
-    if ($form{'iptoken'}) {
-        %sessiondata = &Apache::lonnet::tmpget($form{'iptoken'});
-        my $delete = &Apache::lonnet::tmpdel($form{'iptoken'});
-    }
-
     if (($tmpinfo=~/^error/) || ($tmpinfo eq 'con_lost') || 
         ($tmpinfo eq 'no_such_host')) {
 	&failed($r,'Information needed to verify your login information is missing, inaccessible or expired.',\%form);
@@ -334,22 +492,39 @@ sub handler {
         return OK;
     }
 
-    my ($key,$firsturl,$rolestr,$symbstr)=split(/&/,$tmpinfo);
+    my ($key,$firsturl,$rolestr,$symbstr,$iptokenstr,$linkstr)=split(/&/,$tmpinfo);
     if ($rolestr) {
         $rolestr = &unescape($rolestr);
     }
     if ($symbstr) {
         $symbstr= &unescape($symbstr);
     }
+    if ($iptokenstr) {
+        $iptokenstr = &unescape($iptokenstr);
+    }
+    if ($linkstr) {
+        $linkstr = &unescape($linkstr);
+    }
+    if ($firsturl =~ m{^/tiny/$match_domain/\w+$}) {
+        $form{'firsturl'} = $firsturl;
+    }
     if ($rolestr =~ /^role=/) {
         (undef,$form{'role'}) = split('=',$rolestr);
     }
     if ($symbstr =~ /^symb=/) { 
         (undef,$form{'symb'}) = split('=',$symbstr);
     }
+    if ($iptokenstr =~ /^iptoken=/) {
+        (undef,$form{'iptoken'}) = split('=',$iptokenstr);
+    }
+    if ($linkstr =~ /^linkprot=/) {
+        (undef,$form{'linkprot'}) = split('=',$linkstr);
+    } elsif ($linkstr =~ /^linkkey=/) {
+        (undef,$form{'linkkey'}) = split('=',$linkstr);
+    }
 
-    my $upass = $ENV{HTTPS} ? join("", @form{qw(upass0 upass1 upass2)}) 
-        : decrypt($key, @form{qw(upass0 upass1 upass2)});
+    my $upass = $ENV{HTTPS} ? $form{'upass0'} 
+        : &Apache::loncommon::des_decrypt($key,$form{'upass0'});
 
 # ---------------------------------------------------------------- Authenticate
 
@@ -366,7 +541,7 @@ sub handler {
     my $authhost=Apache::lonnet::authenticate($form{'uname'},$upass,
                                               $form{'udom'},$defaultauth,
                                               $clientcancheckhost);
-    
+
 # --------------------------------------------------------------------- Failed?
 
     if ($authhost eq 'no_host') {
@@ -412,6 +587,8 @@ sub handler {
 
     my $hosthere;
     if ($form{'iptoken'}) {
+        my %sessiondata = &Apache::lonnet::tmpget($form{'iptoken'});
+        my $delete = &Apache::lonnet::tmpdel($form{'iptoken'});
         if (($sessiondata{'domain'} eq $form{'udom'}) &&
             ($sessiondata{'username'} eq $form{'uname'})) {
             $hosthere = 1;
@@ -420,20 +597,68 @@ sub handler {
 
 # --------------------------------- Are we attempting to login as somebody else?
     if ($form{'suname'}) {
+        my ($suname,$sudom,$sudomref);
+        $suname = $form{'suname'};
+        $sudom = $form{'udom'};
+        if ($form{'sudom'}) {
+            unless ($sudom eq $form{'sudom'}) {
+                if (&Apache::lonnet::domain($form{'sudom'})) {
+                    $sudomref = [$form{'sudom'}];
+                    $sudom = $form{'sudom'};
+                }
+            }
+        }
 # ------------ see if the original user has enough privileges to pull this stunt
-	if (&Apache::lonnet::privileged($form{'uname'},$form{'udom'})) {
+	if (&Apache::lonnet::privileged($form{'uname'},$form{'udom'},$sudomref)) {
 # ---------------------------------------------------- see if the su-user exists
-	    unless (&Apache::lonnet::homeserver($form{'suname'},$form{'udom'})
-		eq 'no_host') {
-		&Apache::lonnet::logthis(&Apache::lonnet::homeserver($form{'suname'},$form{'udom'}));
+	    unless (&Apache::lonnet::homeserver($suname,$sudom) eq 'no_host') {
 # ------------------------------ see if the su-user is not too highly privileged
-		unless (&Apache::lonnet::privileged($form{'suname'},$form{'udom'})) {
+		if (&Apache::lonnet::privileged($suname,$sudom)) {
+                    &Apache::lonnet::logthis('Attempted switch user to privileged user');
+                } else {
+                    my $noprivswitch;
+#
+# su-user's home server and user's home server must have one of:
+# (a) same domain
+# (b) same primary library server for the two domains
+# (c) same "internet domain" for primary library server(s) for home servers' domains
+#
+                    my $suprim = &Apache::lonnet::domain($sudom,'primary');
+                    my $suintdom = &Apache::lonnet::internet_dom($suprim);
+                    unless ($sudom eq $form{'udom'}) {
+                        my $uprim = &Apache::lonnet::domain($form{'udom'},'primary');
+                        my $uintdom = &Apache::lonnet::internet_dom($uprim);
+                        unless ($suprim eq $uprim) {
+                            unless ($suintdom eq $uintdom) {
+                                &Apache::lonnet::logthis('Attempted switch user '
+                                   .'to user with different "internet domain".');                        
+                                $noprivswitch = 1;
+                            }
+                        }
+                    }
+
+                    unless ($noprivswitch) {
+#
+# server where log-in occurs must have same "internet domain" as su-user's home
+# server
+#
+                        my $lonhost = $r->dir_config('lonHostID');
+                        my $hostintdom = &Apache::lonnet::internet_dom($lonhost);
+                        if ($hostintdom ne $suintdom) {
+                            &Apache::lonnet::logthis('Attempted switch user on a '
+                                .'server with a different "internet domain".'); 
+                        } else {
+
 # -------------------------------------------------------- actually switch users
-		    &Apache::lonnet::logperm('User '.$form{'uname'}.' at '.$form{'udom'}.
-			' logging in as '.$form{'suname'});
-		    $form{'uname'}=$form{'suname'};
-		} else {
-		    &Apache::lonnet::logthis('Attempted switch user to privileged user');
+
+		            &Apache::lonnet::logperm('User '.$form{'uname'}.' at '.
+                              $form{'udom'}.' logging in as '.$suname.':'.$sudom);
+		            $form{'uname'}=$suname;
+                            if ($form{'udom'} ne $sudom) {
+                                $form{'udom'}=$sudom;
+                            }
+                        }
+                    }
 		}
 	    }
 	} else {
@@ -445,19 +670,36 @@ sub handler {
 
     unless ($hosthere) {
         ($is_balancer,$otherserver) =
-            &Apache::lonnet::check_loadbalancing($form{'uname'},$form{'udom'});
+            &Apache::lonnet::check_loadbalancing($form{'uname'},$form{'udom'},'login');
+        if ($is_balancer) {
+            # Check if browser sent a LON-CAPA load balancer cookie (and this is a balancer)
+            my ($found_server,$balancer_cookie) = &Apache::lonnet::check_for_balancer_cookie($r);
+            if (($found_server) && ($balancer_cookie =~ /^\Q$env{'user.domain'}\E_\Q$env{'user.name'}\E_/)) {
+                $otherserver = $found_server;
+            }
+            if ($otherserver eq '') {
+                my $lowest_load;
+                ($otherserver,undef,undef,undef,$lowest_load) = &Apache::lonnet::choose_server($form{'udom'});
+                if ($lowest_load > 100) {
+                    $otherserver = &Apache::lonnet::spareserver($r,$lowest_load,$lowest_load,1,$form{'udom'});
+                }
+            }
+            if ($otherserver ne '') {
+                my @hosts = &Apache::lonnet::current_machine_ids();
+                if (grep(/^\Q$otherserver\E$/,@hosts)) {
+                    $hosthere = $otherserver;
+                }
+            }
+        }
     }
 
-    if ($is_balancer) {
-        if (!$otherserver) { 
-            ($otherserver) = &Apache::lonnet::choose_server($form{'udom'});
-        }
+    if (($is_balancer) && (!$hosthere)) {
         if ($otherserver) {
             &success($r,$form{'uname'},$form{'udom'},$authhost,'noredirect',undef,
                      \%form);
             my $switchto = '/adm/switchserver?otherserver='.$otherserver;
             if (($firsturl) && ($firsturl ne '/adm/switchserver') && ($firsturl ne '/adm/roles')) {
-                $switchto .= '&origurl='.$firsturl;
+                $switchto .= '&origurl='.$firsturl; #should escape
             }
             if ($form{'role'}) {
                 $switchto .= '&role='.$form{'role'};
@@ -465,8 +707,18 @@ sub handler {
             if ($form{'symb'}) {
                 $switchto .= '&symb='.$form{'symb'};
             }
+            if ($form{'linkprot'}) {
+                $env{'request.linkprot'} = $form{'linkprot'};
+            } elsif ($form{'linkkey'} ne '') {
+                $env{'request.linkkey'} = $form{'linkkey'};
+            }
+            if ($form{'firsturl'} =~ m{^/tiny/$match_domain/\w+$}) {
+                &set_deeplink_login(%form);
+            }
             $r->internal_redirect($switchto);
         } else {
+            &Apache::loncommon::content_type($r,'text/html');
+            $r->send_http_header;
             $r->print(&noswitch());
         }
         return OK;
@@ -478,7 +730,7 @@ sub handler {
                          \%form);
                 my $switchto = '/adm/switchserver?otherserver='.$otherserver;
                 if (($firsturl) && ($firsturl ne '/adm/switchserver') && ($firsturl ne '/adm/roles')) {
-                    $switchto .= '&origurl='.$firsturl;
+                    $switchto .= '&origurl='.$firsturl; #should escape
                 }
                 if ($form{'role'}) {
                     $switchto .= '&role='.$form{'role'};
@@ -486,8 +738,18 @@ sub handler {
                 if ($form{'symb'}) {
                     $switchto .= '&symb='.$form{'symb'};
                 }
+                if ($form{'linkprot'}) {
+                    $env{'request.linkprot'} = $form{'linkprot'};
+                } elsif ($form{'linkkey'} ne '') {
+                    $env{'request.linkkey'} = $form{'linkkey'};
+                }
+                if ($form{'firsturl'} =~ m{^/tiny/$match_domain/\w+$}) {
+                    &set_deeplink_login(%form);
+                }
                 $r->internal_redirect($switchto);
             } else {
+                &Apache::loncommon::content_type($r,'text/html');
+                $r->send_http_header;
                 $r->print(&noswitch());
             }
             return OK;
@@ -508,49 +770,109 @@ sub handler {
 
 # ---------------------------------------------------------- Are we overloaded?
         if ((($userloadpercent>100.0)||($loadpercent>100.0))) {
-            my $unloaded=Apache::lonnet::spareserver($loadpercent,$userloadpercent,1,$form{'udom'});
+            my $unloaded=Apache::lonnet::spareserver($r,$loadpercent,$userloadpercent,1,$form{'udom'});
             if (!$unloaded) {
                 ($unloaded) = &Apache::lonnet::choose_server($form{'udom'});
             }
             if ($unloaded) {
                 &success($r,$form{'uname'},$form{'udom'},$authhost,'noredirect',
                          undef,\%form);
+                if ($form{'linkprot'}) {
+                    $env{'request.linkprot'} = $form{'linkprot'};
+                } elsif ($form{'linkkey'} ne '') {
+                    $env{'request.linkkey'} = $form{'linkkey'};
+                }
+                if ($form{'firsturl'} =~ m{^/tiny/$match_domain/\w+$}) {
+                    &set_deeplink_login(%form);
+                }
                 $r->internal_redirect('/adm/switchserver?otherserver='.$unloaded.'&origurl='.$firsturl);
                 return OK;
             }
         }
-        &success($r,$form{'uname'},$form{'udom'},$authhost,$firsturl,undef,
+        if (($is_balancer) && ($hosthere)) {
+            $form{'noloadbalance'} = $hosthere;
+        }
+        my $extra_env;
+        if ($form{'linkprot'}) {
+            my ($linkprotector,$uri) = split(/:/,$form{'linkprot'},2);
+            if ($linkprotector) {
+                $extra_env = {'user.linkprotector' => $linkprotector,
+                              'user.linkproturi'   => $uri};
+            }
+        } elsif ($form{'linkkey'} ne '') {
+            $extra_env = {'user.deeplinkkey'  => $form{'linkkey'},
+                          'user.keyedlinkuri' => $form{'firsturl'}};
+        }
+        if ($form{'firsturl'} =~ m{^/tiny/$match_domain/\w+$}) {
+            &set_deeplink_login(%form);
+            if ($form{'linkprot'}) {
+                if (ref($extra_env) eq 'HASH') {
+                    %{$extra_env} = ( %{$extra_env}, 'request.linkprot' => $form{'linkprot'} );
+                } else {
+                    $extra_env = {'request.linkprot' => $form{'linkprot'}};
+                }
+            } elsif ($form{'linkkey'} ne '') {
+                if (ref($extra_env) eq 'HASH') {
+                    %{$extra_env} = ( %{$extra_env}, 'request.linkkey' => $form{'linkkey'} );
+                } else {
+                    $extra_env = {'request.linkkey' => $form{'linkkey'}};
+                }
+            }
+            if ($env{'request.deeplink.login'}) {
+                if (ref($extra_env) eq 'HASH') {
+                    %{$extra_env} = ( %{$extra_env}, 'request.deeplink.login' => $form{'firsturl'} );
+                } else {
+                    $extra_env = {'request.deeplink.login' => $form{'firsturl'}};
+                }
+            }
+        }
+        &success($r,$form{'uname'},$form{'udom'},$authhost,$firsturl,$extra_env,
                  \%form);
         return OK;
     }
 }
 
-sub decrypt {
-    my ($key, @chunks) = @_;
-
-    my $keybin = pack("H16",$key);
-
-    my $cipher;
-    if ($Crypt::DES::VERSION >= 2.03) {
-        $cipher = new Crypt::DES $keybin;
-    } else {
-        $cipher = new DES $keybin;
-    }
-
-    my $upass='';
-    for (my $i=0;$i<=2;$i++) {
-        my $chunk =
-            $cipher->decrypt(
-                unpack("a8",pack("H16",substr($chunks[$i],0,16))));
-
-        $chunk .=
-            $cipher->decrypt(
-                unpack("a8",pack("H16",substr($chunks[$i],16,16))));
-
-        $chunk = substr($chunk,1,ord(substr($chunk,0,1)));
-        $upass .= $chunk;
+sub set_deeplink_login {
+    my (%form) = @_;
+    if ($form{'firsturl'} =~ m{^/tiny/($match_domain)/\w+$}) {
+        my $cdom = $1;
+        my ($cnum,$symb) = &Apache::loncommon::symb_from_tinyurl($form{'firsturl'},'',$cdom);
+        if ($symb) {
+            if ($env{'request.course.id'} eq $cdom.'_'.$cnum) {
+                my ($disallow,$deeplink);
+                if ($symb =~ /\.(page|sequence)$/) {
+                    my $mapname = &Apache::lonnet::deversion((&Apache::lonnet::decode_symb($symb))[2]);
+                    my $navmap = Apache::lonnavmaps::navmap->new();
+                    if (ref($navmap)) {
+                        $deeplink = $navmap->get_mapparam(undef,$mapname,'0.deeplink');
+                    }
+                } else {
+                    $deeplink = &Apache::lonnet::EXT('resource.0.deeplink',$symb);
+                }
+                if ($deeplink ne '') {
+                    my ($state,$others,$listed,$scope,$protect) = split(/,/,$deeplink);
+                    if (($protect ne 'none') && ($protect ne '')) {
+                        my ($acctype,$item) = split(/:/,$protect);
+                        if ($acctype =~ /lti(c|d)$/) {
+                            unless ($form{'linkprot'} eq $item.$1.':'.$env{'request.deeplink.login'}) {
+                                $disallow = 1;
+                            }
+                        } elsif ($acctype eq 'key') {
+                            unless ($form{'linkkey'} eq $item) {
+                                $disallow = 1;
+                            }
+                        }
+                    }
+                }
+                unless ($disallow) {
+                    $env{'request.deeplink.login'} = $form{'firsturl'};
+                }
+            } else {
+                $env{'request.deeplink.login'} = $form{'firsturl'};
+            }
+        }
     }
-    return $upass;
+    return;
 }
 
 sub check_can_host {
@@ -593,7 +915,10 @@ sub check_can_host {
             if ($login_host ne '') {
                 my $protocol = $Apache::lonnet::protocol{$login_host};
                 $protocol = 'http' if ($protocol ne 'https');
+                my $alias = &Apache::lonnet::use_proxy_alias($r,$login_host);
+                $hostname = $alias if ($alias ne '');
                 my $newurl = $protocol.'://'.$hostname.'/adm/createaccount';
+#FIXME Should preserve where user was going and linkprot by setting ltoken at $login_host
                 $r->print(&Apache::loncommon::start_page('Create a user account in LON-CAPA').
                           '<h3>'.&mt('Account creation').'</h3>'.
                           &mt('You do not currently have a LON-CAPA account at this institution.').'<br />'.
@@ -610,6 +935,14 @@ sub check_can_host {
         } else {
             &success($r,$form->{'uname'},$udom,$authhost,'noredirect',undef,
                      $form);
+            if ($form->{'linkprot'}) {
+                $env{'request.linkprot'} = $form->{'linkprot'};
+            } elsif ($form->{'firsturl'} =~ m{^/tiny/$match_domain/\w+$}) {
+                if ($form->{'linkkey'} ne '') {
+                    $env{'request.linkkey'} = $form->{'linkkey'};
+                }
+                $env{'request.deeplink.login'} = $form->{'firsturl'};
+            }
             my ($otherserver) = &Apache::lonnet::choose_server($udom);
             $r->internal_redirect('/adm/switchserver?otherserver='.$otherserver);
         }