--- loncom/auth/lonauth.pm	2018/07/04 16:58:19	1.154
+++ loncom/auth/lonauth.pm	2021/11/24 20:15:15	1.171
@@ -1,7 +1,7 @@
 # The LearningOnline Network
 # User Authentication Module
 #
-# $Id: lonauth.pm,v 1.154 2018/07/04 16:58:19 raeburn Exp $
+# $Id: lonauth.pm,v 1.171 2021/11/24 20:15:15 raeburn Exp $
 #
 # Copyright Michigan State University Board of Trustees
 #
@@ -42,11 +42,12 @@ use Apache::lonlocal;
 use Apache::File();
 use HTML::Entities;
 use Digest::MD5;
+use CGI::Cookie();
  
 # ------------------------------------------------------------ Successful login
 sub success {
     my ($r, $username, $domain, $authhost, $lowerurl, $extra_env,
-	$form,$skipcritical) = @_;
+	$form,$skipcritical,$cid,$expirepub) = @_;
 
 # ------------------------------------------------------------ Get cookie ready
     my $cookie =
@@ -60,8 +61,9 @@ 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
 
@@ -108,6 +110,7 @@ sub success {
             }
             $r->send_http_header;
             if (ref($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'} = $env{'request.lti.sourcecrs'};
@@ -147,16 +150,26 @@ sub success {
     }
     if (defined($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);
             $desturl = &Apache::lonnet::clutter($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;
         }
@@ -166,6 +179,22 @@ sub success {
         $destination .= 'source=login';
     }
 
+    if (($env{'request.deeplink.login'} eq $lowerurl) &&
+        (($env{'request.linkprot'}) || ($env{'request.linkkey'} ne ''))) {
+        my %info;
+        if ($env{'request.linkprot'}) {
+            $info{'linkprot'} = $env{'request.linkprot'};
+        } elsif ($env{'request.linkkey'} ne '') {
+            $info{'linkkey'} = $env{'request.linkkey'};
+        }
+        $info{'origurl'} = $lowerurl;
+        my $token = &Apache::lonnet::tmpput(\%info,$r->dir_config('lonHostID'),'link');
+        unless (($token eq 'con_lost') || ($token eq 'refused') ||
+                ($token eq 'unknown_cmd') || ($token eq 'no_such_host')) {
+            $destination .= (($destination =~ /\?/) ? '&' : '?') . 'ttoken='.$token;
+        }
+    }
+
     my $windowname = 'loncapaclient';
     if ($env{'request.lti.login'}) {
         $windowname .= 'lti';
@@ -205,6 +234,12 @@ sub success {
     if ($defaultcookie) {
         $r->headers_out->add('Set-cookie' => $defaultcookie);
     }
+    if ($expirepub) {
+        my $c = new CGI::Cookie(-name    => 'lonPubID',
+                                -value   => '',
+                                -expires => '-10y',);
+        $r->headers_out->add('Set-cookie' => $c);
+    }
     $r->send_http_header;
 
     my ($start_page,$js,$pagebody,$end_page);
@@ -265,7 +300,7 @@ ENDSUCCESS
 # --------------------------------------------------------------- Failed login!
 
 sub failed {
-    my ($r,$message,$form) = @_;
+    my ($r,$message,$form,$authhost) = @_;
     (undef,undef,undef,my $clientmathml,my $clientunicode) =
         &Apache::loncommon::decode_user_agent();
     my $args = {};
@@ -273,46 +308,88 @@ sub failed {
         $args = {'browser.unicode' => 1};
     }
 
+    my @actions;
     my $start_page = &Apache::loncommon::start_page('Unsuccessful Login',undef,$args);
     my $uname = &Apache::loncommon::cleanup_html($form->{'uname'});
     my $udom = &Apache::loncommon::cleanup_html($form->{'udom'});
     if (&Apache::lonnet::domain($udom,'description') eq '') {
         undef($udom);
     }
+    my $authtype;
+    if (($udom ne '') && ($uname ne '') && ($authhost eq 'no_host')) {
+        $authtype = &Apache::lonnet::queryauthenticate($uname,$udom);
+    }
     my $retry = '/adm/login';
-    if ($uname eq $form->{'uname'}) {
+    if (($uname eq $form->{'uname'}) && ($authtype !~ /^lti:/)) {
         $retry .= '?username='.$uname;
     }
     if ($udom) {
         $retry .= (($retry=~/\?/)?'&amp;':'?').'domain='.$udom;
     }
-    if (exists($form->{role})) {
-        my $role = &Apache::loncommon::cleanup_html($form->{role});
-        if ($role ne '') {
-            $retry .= (($retry=~/\?/)?'&amp;':'?').'role='.$role;
+    my $lonhost = $r->dir_config('lonHostID');
+    my $querystr;
+    my $result = &set_retry_token($form,$lonhost,\$querystr);
+    if ($result eq 'fail') {
+        if (exists($form->{role})) {
+            my $role = &Apache::loncommon::cleanup_html($form->{role});
+            if ($role ne '') {
+                $retry .= (($retry=~/\?/)?'&amp;':'?').'role='.$role;
+            }
+        }
+        if (exists($form->{symb})) {
+            my $symb = &Apache::loncommon::cleanup_html($form->{symb});
+            if ($symb ne '') {
+                $retry .= (($retry=~/\?/)?'&amp;':'?').'symb='.$symb;
+            }
+        }
+        if (exists($form->{firsturl})) {
+            my $firsturl = &Apache::loncommon::cleanup_html($form->{firsturl});
+            if ($firsturl ne '') {
+                $retry .= (($retry=~/\?/)?'&amp;':'?').'firsturl='.$firsturl;
+                if ($form->{firsturl} =~ m{^/tiny/$match_domain/\w+$}) {
+                    unless (exists($form->{linkprot})) {
+                        if (exists($form->{linkkey})) {
+                            $retry .= 'linkkey='.$form->{linkkey};
+                        }
+                    }
+                }
+            }
         }
-    }
-    if (exists($form->{symb})) {
-        my $symb = &Apache::loncommon::cleanup_html($form->{symb});
-        if ($symb ne '') {
-            $retry .= (($retry=~/\?/)?'&amp;':'?').'symb='.$symb;
+        if (exists($form->{linkprot})) {
+            my $ltoken = &Apache::lonnet::tmpput({linkprot => $form->{'linkprot'}},
+                                                 $r->dir_config('lonHostID'),'retry');
+            if ($ltoken) {
+                $retry .= (($retry =~ /\?/) ? '&' : '?').'ltoken='.$ltoken;
+            }
         }
+    } elsif ($querystr ne '') {
+        $retry .= (($retry=~/\?/)?'&amp;':'?').$querystr;
     }
     my $end_page = &Apache::loncommon::end_page();
     &Apache::loncommon::content_type($r,'text/html');
     $r->send_http_header;
-    my @actions =
-         (&mt('Please [_1]log in again[_2].','<a href="'.$retry.'">','</a>'));
+    if ($authtype =~ /^lti:/) {
+        $message = &mt('Direct login is not supported with the username you entered.').
+                   '<br /><br />'.
+                   &mt('You likely need to launch LON-CAPA from within a course in a different Learning Management System.').
+                   '<br />'.
+                   &mt('You can also try to log in with a different username.');
+        @actions = 
+            (&mt('Try your [_1]log in again[_2].','<a href="'.$retry.'">','</a>'));
+    } else {
+        $message = &mt($message);
+        @actions =
+            (&mt('Please [_1]log in again[_2].','<a href="'.$retry.'">','</a>'));
+    }
     my $loginhelp = &loginhelpdisplay($udom);
     if ($loginhelp) {
         push(@actions, '<a href="'.$loginhelp.'">'.&mt('Login problems?').'</a>');
     }
     #FIXME: link to helpdesk might be added here
-
     $r->print(
        $start_page
       .'<h2>'.&mt('Sorry ...').'</h2>'
-      .&Apache::lonhtmlcommon::confirm_success(&mt($message),1).'<br /><br />'
+      .&Apache::lonhtmlcommon::confirm_success($message,1).'<br /><br />'
       .&Apache::lonhtmlcommon::actionbox(\@actions)
       .$end_page
     );
@@ -354,21 +431,76 @@ 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 = $env{'form.firsturl'};
+            my %form = &get_form_items($r);
+            if ($form{'logtoken'}) {
+                my $tmpinfo = &Apache::lonnet::reply('tmpget:'.$form{'logtoken'},
+                                                     $form{'serverid'});
+                unless (($tmpinfo=~/^error/) || ($tmpinfo eq 'con_lost') ||
+                        ($tmpinfo eq 'no_such_host')) {
+                    my ($des_key,$firsturl,@rest)=split(/&/,$tmpinfo);
+                    $firsturl = &unescape($firsturl);
+                    my %info;
+                    foreach my $item (@rest) {
+                        my ($key,$value) = split(/=/,$item);
+                        $info{$key} = &unescape($value);
+                    }
+                    if ($firsturl ne '') {
+                        $info{'firsturl'} = $firsturl;
+                        $dest = $firsturl;
+                        my $relogin;
+                        if ($dest =~ m{^/tiny/$match_domain/\w+$}) {
+                            if ($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) {
+                                    unless (&set_deeplink_login(%info) eq 'ok') {
+                                        $relogin = 1;
+                                    }
+                                }
+                            }
+                            if ($relogin) {
+                                $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);
+                            } else {
+                                if (($info{'linkprot'}) || ($info{'linkkey'} ne '')) {
+                                    my $token = &Apache::lonnet::tmpput(\%info,$r->dir_config('lonHostID'),'link');
+                                    unless (($token eq 'con_lost') || ($token eq 'refused') ||
+                                            ($token eq 'unknown_cmd') || ($token eq 'no_such_host')) {
+                                        $dest .= (($dest =~ /\?/) ? '&' : '?') . 'ttoken='.$token;
+                                    }
+                                }
+                                $r->print(
+                                      $start_page
+                                     .'<p class="LC_warning">'.&mt('You are already logged in!').'</p>'
+                                     .'<p>'.&mt('Please either [_1]continue the current session[_2] or [_3]log out[_4] first, and then try your access again',
+                                                '<a href="'.$dest.'">','</a>',
+                                                '<a href="/adm/logout">','</a>')
+                                     .'</p>'
+                                     .$end_page);
+                            }
+                            return OK;
+                        }
+                    }
+                }
             }
             $r->print(
-               $start_page
-              .'<p class="LC_warning">'.&mt('You are already logged in!').'</p>'
-              .'<p>'.&mt('Please either [_1]continue the current session[_2] or [_3]log out[_4].'
-                    ,'<a href="'.$dest.'">','</a>','<a href="/adm/logout">','</a>')
-              .'</p>'
-              .$end_page
+                  $start_page
+                 .'<p class="LC_warning">'.&mt('You are already logged in!').'</p>'
+                 .'<p>'.&mt('Please either [_1]continue the current session[_2] or [_3]log out[_4].'
+                          ,'<a href="'.$dest.'">','</a>','<a href="/adm/logout">','</a>')
+                 .'</p>'
+                 .$end_page
             );
             return OK;
         }
@@ -376,19 +508,7 @@ sub handler {
 
 # ---------------------------------------------------- No valid token, continue
 
-
-    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}=$value;
-    }
-
+    my %form = &get_form_items($r);
     if ((!$form{'uname'}) || (!$form{'upass0'}) || (!$form{'udom'})) {
 	&failed($r,'Username, password and domain need to be specified.',
 		\%form);
@@ -432,28 +552,17 @@ sub handler {
         return OK;
     }
 
-    my ($key,$firsturl,$rolestr,$symbstr,$iptokenstr)=split(/&/,$tmpinfo);
-    if ($rolestr) {
-        $rolestr = &unescape($rolestr);
-    }
-    if ($symbstr) {
-        $symbstr= &unescape($symbstr);
-    }
-    if ($iptokenstr) {
-        $iptokenstr = &unescape($iptokenstr);
+    my ($des_key,$firsturl,@rest)=split(/&/,$tmpinfo);
+    $firsturl = &unescape($firsturl);
+    foreach my $item (@rest) {
+        my ($key,$value) = split(/=/,$item);
+        $form{$key} = &unescape($value);
     }
-    if ($rolestr =~ /^role=/) {
-        (undef,$form{'role'}) = split('=',$rolestr);
+    if ($firsturl =~ m{^/tiny/$match_domain/\w+$}) {
+        $form{'firsturl'} = $firsturl;
     }
-    if ($symbstr =~ /^symb=/) { 
-        (undef,$form{'symb'}) = split('=',$symbstr);
-    }
-    if ($iptokenstr =~ /^iptoken=/) {
-        (undef,$form{'iptoken'}) = split('=',$iptokenstr);
-    }
-
     my $upass = $ENV{HTTPS} ? $form{'upass0'} 
-        : &Apache::loncommon::des_decrypt($key,$form{'upass0'});
+        : &Apache::loncommon::des_decrypt($des_key,$form{'upass0'});
 
 # ---------------------------------------------------------------- Authenticate
 
@@ -475,7 +584,7 @@ sub handler {
 
     if ($authhost eq 'no_host') {
 	&failed($r,'Username and/or password could not be authenticated.',
-		\%form);
+		\%form,$authhost);
         return OK;
     } elsif ($authhost eq 'no_account_on_host') {
         if ($defaultauth) {
@@ -484,7 +593,8 @@ sub handler {
                 return OK;
             }
             my $start_page = 
-                &Apache::loncommon::start_page('Create a user account in LON-CAPA');
+                &Apache::loncommon::start_page('Create a user account in LON-CAPA',
+                                               '',{'no_inline_link'   => 1,});
             my $lonhost = $r->dir_config('lonHostID');
             my $origmail = $Apache::lonnet::perlvar{'lonSupportEMail'};
             my $contacts = 
@@ -514,9 +624,9 @@ sub handler {
 	$firsturl='/adm/roles';
     }
 
-    my $hosthere;
+    my ($hosthere,%sessiondata);
     if ($form{'iptoken'}) {
-        my %sessiondata = &Apache::lonnet::tmpget($form{'iptoken'});
+        %sessiondata = &Apache::lonnet::tmpget($form{'iptoken'});
         my $delete = &Apache::lonnet::tmpdel($form{'iptoken'});
         if (($sessiondata{'domain'} eq $form{'udom'}) &&
             ($sessiondata{'username'} eq $form{'uname'})) {
@@ -560,7 +670,7 @@ sub handler {
                         unless ($suprim eq $uprim) {
                             unless ($suintdom eq $uintdom) {
                                 &Apache::lonnet::logthis('Attempted switch user '
-                                   .'to user with different "internet domain".');                        
+                                   .'to user with different "internet domain".');
                                 $noprivswitch = 1;
                             }
                         }
@@ -601,11 +711,16 @@ sub handler {
         ($is_balancer,$otherserver) =
             &Apache::lonnet::check_loadbalancing($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) {
-                    $otherserver = &Apache::lonnet::spareserver($lowest_load,$lowest_load,1,$form{'udom'});
+                    $otherserver = &Apache::lonnet::spareserver($r,$lowest_load,$lowest_load,1,$form{'udom'});
                 }
             }
             if ($otherserver ne '') {
@@ -631,8 +746,18 @@ 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;
             $r->print(&noswitch());
         }
         return OK;
@@ -652,8 +777,18 @@ sub handler {
                 if ($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;
@@ -674,13 +809,21 @@ 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='.$firsturl);
                 return OK;
             }
@@ -688,12 +831,150 @@ sub handler {
         if (($is_balancer) && ($hosthere)) {
             $form{'noloadbalance'} = $hosthere;
         }
-        &success($r,$form{'uname'},$form{'udom'},$authhost,$firsturl,undef,
+        my $extra_env;
+        if (($hosthere) && ($sessiondata{'sessionserver'} ne '')) {
+            if ($sessiondata{'origurl'} ne '') {
+                $firsturl = $sessiondata{'origurl'};
+                $form{'firsturl'} = $sessiondata{'origurl'};
+                my @names = ('role','symb','linkprot','linkkey');
+                foreach my $item (@names) {
+                    if ($sessiondata{$item} ne '') {
+                        $form{$item} = $sessiondata{$item};
+                    }
+                }
+            }
+        }
+        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 get_form_items {
+    my ($r) = @_;
+    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;
+    }
+    return %form;
+}
+
+sub set_deeplink_login {
+    my (%form) = @_;
+    my $disallow;
+    if ($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 $deeplink;
+                if ($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'} = $form{'firsturl'};
+            }
+        }
+    }
+    if ($disallow) {
+        return;
+    }
+    return 'ok';
+}
+
+sub set_retry_token {
+    my ($form,$lonhost,$querystr) = @_;
+    if (ref($form) eq 'HASH') {
+        my ($firsturl,$token,$extras,@names);
+        @names = ('role','symb','linkprot','linkkey','iptoken');
+        foreach my $name (@names) {
+            if ($form->{$name} ne '') {
+                $extras .= '&'.$name.'='.&escape($form->{$name});
+                last if ($name eq 'linkprot');
+            }
+        }
+        my $firsturl = $form->{'firsturl'};
+        if (($firsturl ne '') || ($extras ne '')) {
+            $extras .= ':retry';
+            $token = &Apache::lonnet::reply('tmpput:'.&escape($firsturl).
+                                            $extras,$lonhost);
+            if (($token eq 'con_lost') || ($token eq 'no_such_host')) {
+                return 'fail';
+            } else {
+                if (ref($querystr)) {
+                    $$querystr = 'retry='.$token;
+                }
+                return 'ok';
+            }
+        }
+    }
+    return;
+}
+
 sub check_can_host {
     my ($r,$form,$authhost,$domdesc) = @_;
     return unless (ref($form) eq 'HASH');
@@ -734,7 +1015,10 @@ 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
                 $r->print(&Apache::loncommon::start_page('Create a user account in LON-CAPA').
                           '<h3>'.&mt('Account creation').'</h3>'.
                           &mt('You do not currently have a LON-CAPA account at this institution.').'<br />'.
@@ -751,6 +1035,14 @@ sub check_can_host {
         } else {
             &success($r,$form->{'uname'},$udom,$authhost,'noredirect',undef,
                      $form);
+            if ($form->{'firsturl'} =~ m{^/tiny/$match_domain/\w+$}) {
+                $env{'request.deeplink.login'} = $form->{'firsturl'};
+            }
+            if ($form->{'linkprot'}) {
+                $env{'request.linkprot'} = $form->{'linkprot'};
+            } elsif ($form->{'linkkey'} ne '') {
+                $env{'request.linkkey'} = $form->{'linkkey'};
+            }
             my ($otherserver) = &Apache::lonnet::choose_server($udom);
             $r->internal_redirect('/adm/switchserver?otherserver='.$otherserver);
         }