--- loncom/auth/lonacc.pm	2013/12/13 01:41:08	1.148
+++ loncom/auth/lonacc.pm	2020/10/06 17:26:15	1.182
@@ -1,7 +1,7 @@
 # The LearningOnline Network
 # Cookie Based Access Handler
 #
-# $Id: lonacc.pm,v 1.148 2013/12/13 01:41:08 raeburn Exp $
+# $Id: lonacc.pm,v 1.182 2020/10/06 17:26:15 raeburn Exp $
 #
 # Copyright Michigan State University Board of Trustees
 #
@@ -102,6 +102,7 @@ use Apache::loncommon();
 use Apache::lonlocal;
 use Apache::restrictedaccess();
 use Apache::blockedaccess();
+use Apache::lonprotected();
 use Fcntl qw(:flock);
 use LONCAPA qw(:DEFAULT :match);
 
@@ -109,7 +110,6 @@ sub cleanup {
     my ($r)=@_;
     if (! $r->is_initial_req()) { return DECLINED; }
     &Apache::lonnet::save_cache();
-    &Apache::lontexconvert::jsMath_reset();
     return OK;
 }
 
@@ -160,6 +160,8 @@ sub get_posted_cgi {
                         if (length($value) == 1) {
                             $value=~s/[\r\n]$//;
                         }
+                    } elsif ($fname =~ /\.(xls|doc|ppt)(x|m)$/i) {
+                        $value=~s/[\r\n]$//;
                     }
                     if (ref($fields) eq 'ARRAY') {
                         next if (!grep(/^\Q$name\E$/,@{$fields}));
@@ -201,6 +203,14 @@ sub get_posted_cgi {
 			$fname='';
 			$fmime='';
 		    }
+                    if ($i<$#lines && $lines[$i+1]=~/^Content\-Type\:\s*([\w\-\/]+)/i) {
+                        # TODO: something with $1 !
+                        $i++;
+                    }
+                    if ($i<$#lines && $lines[$i+1]=~/^Content\-transfer\-encoding\:\s*([\w\-\/]+)/i) {
+                        # TODO: something with $1 !
+                        $i++;
+                    }
 		    $i++;
 		}
 	    } else {
@@ -264,26 +274,33 @@ sub upload_size_allowed {
 =item sso_login()
 
 	handle the case of the single sign on user, at this point $r->user 
-	will be set and valia;d now need to find the loncapa user info, and possibly
-	balance them. If Apache >= 2.4, $r->user() will also have been set so 
-        $curruser is checked, and if null, this is an SSO case.
-	returns OK if it was a SSO and user was handled
-        undef if not SSO or no means to hanle the user
+	will be set and valid; now need to find the loncapa user info, and possibly
+	balance them. If $r->user() is set this means either it was either set by
+        SSO or by checkauthen.pm, if a valid cookie was found. The latter case can
+        be identified by the third arg ($usename), except when lonacc is called in 
+        an internal redirect to /adm/switchserver (e.g., load-balancing following
+        successful authentication) -- no cookie set yet.  For that particular case
+        simply skip the call to sso_login(). 
+
+	returns OK if it was SSO and user was handled.
+        returns undef if not SSO or no means to handle the user.
         
 =cut
 
 sub sso_login {
-    my ($r,$handle,$curruser) = @_;
+    my ($r,$handle,$username) = @_;
 
-    my $lonidsdir=$r->dir_config('lonIDsDir');
-    if (($r->user eq '') || ($curruser ne '') ||
+    if (($r->user eq '') || ($username ne '') || ($r->user eq 'public:public') ||
         (defined($env{'user.name'}) && (defined($env{'user.domain'}))
 	  && ($handle ne ''))) {
 	# not an SSO case or already logged in
 	return undef;
     }
 
-    my ($user) = ($r->user =~ m/([a-zA-Z0-9_\-@.]*)/);
+    my ($user) = ($r->user =~ m/^($match_username)$/);
+    if ($user eq '') {
+        return undef;
+    }
 
     my $query = $r->args;
     my %form;
@@ -300,7 +317,10 @@ sub sso_login {
     my %sessiondata;
     if ($form{'iptoken'}) {
         %sessiondata = &Apache::lonnet::tmpget($form{'iptoken'});
-        my $delete = &Apache::lonnet::tmpdel($form{'token'});
+        my $delete = &Apache::lonnet::tmpdel($form{'iptoken'});
+        unless ($sessiondata{'sessionserver'}) {
+            delete($form{'iptoken'});
+        }
     }
 
     my $domain = $r->dir_config('lonSSOUserDomain');
@@ -312,20 +332,46 @@ sub sso_login {
 	&Apache::lonnet::logthis(" SSO authorized user $user ");
         my ($is_balancer,$otherserver,$hosthere);
         if ($form{'iptoken'}) {
-            if (($sessiondata{'domain'} eq $form{'udom'}) &&
-                ($sessiondata{'username'} eq $form{'uname'})) {
+            if (($sessiondata{'domain'} eq $domain) &&
+                ($sessiondata{'username'} eq $user)) {
                 $hosthere = 1;
             }
         }
         unless ($hosthere) {
             ($is_balancer,$otherserver) =
-                &Apache::lonnet::check_loadbalancing($user,$domain);
+                &Apache::lonnet::check_loadbalancing($user,$domain,'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$domain\E_\Q$user\E_/)) {
+                    $otherserver = $found_server;
+                } elsif ($otherserver eq '') {
+                    my $lowest_load;
+                    ($otherserver,undef,undef,undef,$lowest_load) = &Apache::lonnet::choose_server($domain);
+                    if ($lowest_load > 100) {
+                        $otherserver = &Apache::lonnet::spareserver($lowest_load,$lowest_load,1,$domain);
+                    }
+                    if ($otherserver ne '') {
+                        my @hosts = &Apache::lonnet::current_machine_ids();
+                        if (grep(/^\Q$otherserver\E$/,@hosts)) {
+                            $hosthere = $otherserver;
+                        }
+                    }
+                }
+            }
         }
-
-	if ($is_balancer) {
+	if (($is_balancer) && (!$hosthere)) {
 	    # login but immediately go to switch server to find us a new 
 	    # machine
 	    &Apache::lonauth::success($r,$user,$domain,$home,'noredirect');
+            foreach my $item (keys(%form)) {
+                $env{'form.'.$item} = $form{$item};
+            }
+            unless ($form{'symb'}) {
+                unless (($r->uri eq '/adm/roles') || ($r->uri eq '/adm/sso')) {
+                    $env{'form.origurl'} = $r->uri;
+                }
+            }
             $env{'request.sso.login'} = 1;
             if (defined($r->dir_config("lonSSOReloginServer"))) {
                 $env{'request.sso.reloginserver'} =
@@ -340,25 +386,23 @@ sub sso_login {
 	} else {
 	    # need to login them in, so generate the need data that
 	    # migrate expects to do login
-	    my $ip;
-	    my $c = $r->connection;
-	    eval {
-	        $ip = $c->remote_ip();
-	    };
-	    if ($@) {
-	        $ip = $c->client_ip();
-	    }
+	    my $ip = $r->get_remote_host();
 	    my %info=('ip'        => $ip,
 		      'domain'    => $domain,
 		      'username'  => $user,
 		      'server'    => $r->dir_config('lonHostID'),
 		      'sso.login' => 1
 		      );
-            foreach my $item ('role','symb') {
+            foreach my $item ('role','symb','iptoken') {
                 if (exists($form{$item})) {
                     $info{$item} = $form{$item};
                 }
             }
+            unless ($info{'symb'}) {
+                unless (($r->uri eq '/adm/roles') || ($r->uri eq '/adm/sso')) {
+                    $info{'origurl'} = $r->uri; 
+                }
+            }
             if ($r->dir_config("ssodirecturl") == 1) {
                 $info{'origurl'} = $r->uri;
             }
@@ -366,6 +410,9 @@ sub sso_login {
                 $info{'sso.reloginserver'} = 
                     $r->dir_config('lonSSOReloginServer'); 
             }
+            if (($is_balancer) && ($hosthere)) {
+                $info{'noloadbalance'} = $hosthere;
+            }
 	    my $token = 
 		&Apache::lonnet::tmpput(\%info,
 					$r->dir_config('lonHostID'));
@@ -374,10 +421,8 @@ sub sso_login {
 	    $r->set_handlers('PerlHandler'=> undef);
 	}
 	return OK;
-    } elsif (defined($r->dir_config('lonSSOUserUnknownRedirect'))) {
+    } else {
 	&Apache::lonnet::logthis(" SSO authorized unknown user $user ");
-        $r->subprocess_env->set('SSOUserUnknown' => $user);
-        $r->subprocess_env->set('SSOUserDomain' => $domain);
         my @cancreate;
         my %domconfig =
             &Apache::lonnet::get_dom('configuration',['usercreation'],$domain);
@@ -391,13 +436,18 @@ sub sso_login {
                 }
             }
         }
-        if (grep(/^sso$/,@cancreate)) {
-            $r->internal_redirect('/adm/createaccount');
-        } else {
-	    $r->internal_redirect($r->dir_config('lonSSOUserUnknownRedirect'));
+        if ((grep(/^sso$/,@cancreate)) || (defined($r->dir_config('lonSSOUserUnknownRedirect')))) {
+            $r->subprocess_env->set('SSOUserUnknown' => $user);
+            $r->subprocess_env->set('SSOUserDomain' => $domain);
+            if (grep(/^sso$/,@cancreate)) {
+                $r->set_handlers('PerlHandler'=> [\&Apache::createaccount::handler]);
+                $r->handler('perl-script');
+            } else {
+	        $r->internal_redirect($r->dir_config('lonSSOUserUnknownRedirect'));
+                $r->set_handlers('PerlHandler'=> undef);
+            }
+	    return OK;
         }
-	$r->set_handlers('PerlHandler'=> undef);
-	return OK;
     }
     return undef;
 }
@@ -405,27 +455,33 @@ sub sso_login {
 sub handler {
     my $r = shift;
     my $requrl=$r->uri;
-    if (&Apache::lonnet::is_domainimage($requrl)) {
+
+    if ($requrl =~ m{^/res/adm/pages/[^/]+\.(gif|png)$}) {
         return OK;
     }
 
-    if ($requrl =~ m{^/res/adm/pages/[^/]+\.(gif|png)$}) {
+    if (&Apache::lonnet::is_domainimage($requrl)) {
         return OK;
     }
 
-    my $curruser;
-    my $handle = &Apache::lonnet::check_for_valid_session($r,undef,\$curruser);
+    my %user;
+    my $handle = &Apache::lonnet::check_for_valid_session($r,undef,\%user);
 
-    my $result = &sso_login($r,$handle,$curruser);
-    if (defined($result)) {
-	return $result;
+    unless (($requrl eq '/adm/switchserver') && (!$r->is_initial_req())) {
+        my $result = &sso_login($r,$handle,$user{'name'});
+        if (defined($result)) {
+	    return $result;
+        }
     }
 
     my ($is_balancer,$otherserver);
 
     if ($handle eq '') {
-        unless (($requrl eq '/adm/switchserver') && (!$r->is_initial_req())) {
-	    $r->log_reason("Cookie $handle not valid", $r->filename);
+        unless ((($requrl eq '/adm/switchserver') && (!$r->is_initial_req())) ||
+                ($requrl =~ m{^/public/$match_domain/$match_courseid/syllabus}) ||
+                ($requrl =~ m{^/adm/help/}) ||
+                ($requrl =~ m{^/res/$match_domain/$match_username/})) {
+	    $r->log_reason("Cookie not valid", $r->filename);
         }
     } elsif ($handle ne '') {
 
@@ -455,14 +511,14 @@ sub handler {
 	}
 	$env{'request.filename'} = $r->filename;
 	$env{'request.noversionuri'} = &Apache::lonnet::deversion($requrl);
-        my $suppext;
+        my ($suppext,$checkabsolute);
         if ($requrl =~ m{^/adm/wrapper/ext/}) {
             my $query = $r->args;
             if ($query) {
                 my $preserved;
                 foreach my $pair (split(/&/,$query)) {
                     my ($name, $value) = split(/=/,$pair);
-                    unless ($name eq 'symb') {
+                    unless (($name eq 'symb') || ($name eq 'usehttp')) {
                         $preserved .= $pair.'&';
                     }
                     if (($env{'request.course.id'}) && ($name eq 'folderpath')) {
@@ -476,9 +532,13 @@ sub handler {
                     $env{'request.external.querystring'} = $preserved;
                 }
             }
+            if ($env{'request.course.id'}) {
+                $checkabsolute = 1;
+            }
         } elsif ($env{'request.course.id'} &&
                  (($requrl =~ m{^/adm/$match_domain/$match_username/aboutme$}) ||
-                  ($requrl =~ m{^/public/$cdom/$cnum/syllabus$}))) {
+                  ($requrl eq "/public/$cdom/$cnum/syllabus") ||
+                  ($requrl =~ m{^/adm/$cdom/$cnum/\d+/ext\.tool$}))) {
             my $query = $r->args;
             if ($query) {
                 foreach my $pair (split(/&/,$query)) {
@@ -487,9 +547,25 @@ sub handler {
                         if ($value =~ /^supplemental/) {
                             $suppext = 1;
                         }
+                        last;
                     }
                 }
             }
+            if ($requrl =~ m{^/public/$cdom/$cnum/syllabus$}) {
+                $checkabsolute = 1;
+            }
+        }
+        if ($checkabsolute) {
+            my $hostname = $r->hostname();
+            my $lonhost = &Apache::lonnet::host_from_dns($hostname);
+            if ($lonhost) {
+                my $actual = &Apache::lonnet::absolute_url($hostname);
+                my $exphostname = &Apache::lonnet::hostname($lonhost);
+                my $expected = $Apache::lonnet::protocol{$lonhost}.'://'.$hostname;
+                unless ($actual eq $expected) {
+                    $env{'request.use_absolute'} = $expected;
+                }
+            }
         }
 # -------------------------------------------------------- Load POST parameters
 
@@ -500,7 +576,7 @@ sub handler {
         my $checkexempt;
         if ($env{'user.loadbalexempt'} eq $r->dir_config('lonHostID')) {
             if ($env{'user.loadbalcheck.time'} + 600 > time) {
-                $checkexempt = 1;    
+                $checkexempt = 1;
             }
         }
         if ($env{'user.noloadbalance'} eq $r->dir_config('lonHostID')) {
@@ -510,20 +586,102 @@ sub handler {
             ($is_balancer,$otherserver) =
                 &Apache::lonnet::check_loadbalancing($env{'user.name'},
                                                      $env{'user.domain'});
+            if ($is_balancer) {
+                unless (($requrl eq '/adm/switchserver') && (!$r->is_initial_req())) {
+                    # 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 = $found_server;
+                    }
+                }
+            }
         }
         if ($is_balancer) {
-            $r->set_handlers('PerlResponseHandler'=>
-                             [\&Apache::switchserver::handler]);
-            if ($otherserver ne '') {
-                $env{'form.otherserver'} = $otherserver;
+            unless (($requrl eq '/adm/switchserver') && (!$r->is_initial_req())) {
+                $r->set_handlers('PerlResponseHandler'=>
+                                 [\&Apache::switchserver::handler]);
+                if ($otherserver ne '') {
+                    $env{'form.otherserver'} = $otherserver;
+                }
+            }
+            unless (($env{'form.origurl'}) || ($r->uri eq '/adm/roles') ||
+                    ($r->uri eq '/adm/switchserver') || ($r->uri eq '/adm/sso')) {
+                $env{'form.origurl'} = $r->uri;
+            }
+        }
+        if ($requrl=~m{^/+tiny/+$match_domain/+\w+$}) {
+            if ($env{'user.name'} eq 'public' &&
+                $env{'user.domain'} eq 'public') {
+                $env{'request.firsturl'}=$requrl;
+                return FORBIDDEN;
+            } else {
+                return OK;
             }
         }
-
 # ---------------------------------------------------------------- Check access
 	my $now = time;
-	if ($requrl !~ m{^/(?:adm|public|prtspool)/}
+        my $check_symb;
+	if ($requrl !~ m{^/(?:adm|public|(?:prt|zip)spool)/}
 	    || $requrl =~ /^\/adm\/.*\/(smppg|bulletinboard)(\?|$ )/x) {
-	    my $access=&Apache::lonnet::allowed('bre',$requrl);
+            my ($access,$poss_symb);
+            if (($env{'request.course.id'}) && (!$suppext)) {
+                $requrl=~/\.(\w+)$/;
+                if ((&Apache::loncommon::fileembstyle($1) eq 'ssi') ||
+                    ($requrl=~/^\/adm\/.*\/(aboutme|smppg|bulletinboard)(\?|$ )/x) ||
+                    ($requrl=~/^\/adm\/wrapper\//) ||
+                    ($requrl=~m|^/adm/coursedocs/showdoc/|) ||
+                    ($requrl=~m|\.problem/smpedit$|) ||
+                    ($requrl=~/^\/public\/.*\/syllabus$/) ||
+                    ($requrl=~/^\/adm\/(viewclasslist|navmaps)$/) ||
+                    ($requrl=~/^\/adm\/.*\/aboutme\/portfolio(\?|$)/) ||
+                    ($requrl=~m{^/adm/$cdom/$cnum/\d+/ext\.tool$})) {
+                    $check_symb = 1;
+                }
+            }
+            if ($check_symb) {
+                if ($env{'form.symb'}) {
+                    $poss_symb=&Apache::lonnet::symbclean($env{'form.symb'});
+                } elsif (($env{'request.course.id'}) && ($r->args ne '')) {
+                    my $query = $r->args;
+                    foreach my $pair (split(/&/,$query)) {
+                        my ($name, $value) = split(/=/,$pair);
+                        $name = &unescape($name);
+                        $value =~ tr/+/ /;
+                        $value =~ s/%([a-fA-F0-9][a-fA-F0-9])/pack("C",hex($1))/eg;
+                        if ($name eq 'symb') {
+                            $poss_symb = &Apache::lonnet::symbclean($value);
+                            last;
+                        }
+                    }
+                }
+                if ($poss_symb) {
+                    my ($possmap,$resid,$url)=&Apache::lonnet::decode_symb($poss_symb);
+                    $url = &Apache::lonnet::clutter($url);
+                    unless (($url eq $requrl) && (&Apache::lonnet::is_on_map($possmap))) {
+                        undef($poss_symb);
+                    }
+                    if ($poss_symb) {
+                        if ((!$env{'request.role.adv'}) && ($env{'acc.randomout'}) &&
+                            ($env{'acc.randomout'}=~/\&\Q$poss_symb\E\&/)) {
+                            undef($poss_symb);
+                        }
+                    }
+                }
+                if ($poss_symb) {
+                    $access=&Apache::lonnet::allowed('bre',$requrl,$poss_symb);
+                } else {
+                    $access=&Apache::lonnet::allowed('bre',$requrl,'','','','',1);
+                }
+            } else {
+                $access=&Apache::lonnet::allowed('bre',$requrl);
+            }
+            if ($handle eq '') {
+                unless ($access eq 'F') {
+                    if ($requrl =~ m{^/res/$match_domain/$match_username/}) {
+                        $r->log_reason("Cookie not valid", $r->filename);
+                    }
+                }
+            }
 	    if ($access eq '1') {
 		$env{'user.error.msg'}="$requrl:bre:0:0:Choose Course";
 		return HTTP_NOT_ACCEPTABLE; 
@@ -533,9 +691,21 @@ sub handler {
 		return OK;
 	    }
             if ($access eq 'B') {
+                if ($poss_symb) {
+                    if ($requrl=~m{^(/adm/.*/aboutme)/portfolio$}) {
+                        $requrl = $1;
+                    }
+                    if (&Apache::lonnet::symbverify($poss_symb,$requrl)) {
+                        $env{'request.symb'} = $poss_symb;
+                    }
+                }
                 &Apache::blockedaccess::setup_handler($r);
                 return OK;
             }
+            if ($access eq 'D') {
+                &Apache::lonprotected::setup_handler($r);
+                return OK;
+            }
 	    if (($access ne '2') && ($access ne 'F')) {
                 if ($requrl =~ m{^/res/}) {
                     $access = &Apache::lonnet::allowed('bro',$requrl);
@@ -551,6 +721,12 @@ sub handler {
                             return HTTP_NOT_ACCEPTABLE;
                         }
                     }
+                } elsif (($handle =~ /^publicuser_\d+$/) && (&Apache::lonnet::is_portfolio_url($requrl))) {
+                    my $clientip = $r->get_remote_host();
+                    if (&Apache::lonnet::allowed('bre',$requrl,undef,undef,$clientip) ne 'F') {
+                        $env{'user.error.msg'}="$requrl:bre:1:1:Access Denied";
+                        return HTTP_NOT_ACCEPTABLE;
+                    }
                 } else {
 		    $env{'user.error.msg'}="$requrl:bre:1:1:Access Denied";
 		    return HTTP_NOT_ACCEPTABLE;
@@ -577,7 +753,7 @@ sub handler {
 	    $env{'user.domain'} eq 'public' &&
 	    $requrl !~ m{^/+(res|public|uploaded)/} &&
 	    $requrl !~ m{^/adm/[^/]+/[^/]+/aboutme/portfolio$ }x &&
-        $requrl !~ m{^/adm/blockingstatus/.*$} &&
+            $requrl !~ m{^/adm/blockingstatus/.*$} &&
 	    $requrl !~ m{^/+adm/(help|logout|restrictedaccess|randomlabel\.png)}) {
 	    $env{'request.querystring'}=$r->args;
 	    $env{'request.firsturl'}=$requrl;
@@ -586,16 +762,8 @@ sub handler {
 # ------------------------------------------------------------- This is allowed
 	if ($env{'request.course.id'}) {
 	    &Apache::lonnet::countacc($requrl);
-	    $requrl=~/\.(\w+)$/;
             my $query=$r->args;
-	    if ((&Apache::loncommon::fileembstyle($1) eq 'ssi') ||
-		($requrl=~/^\/adm\/.*\/(aboutme|smppg|bulletinboard)(\?|$ )/x) ||
-		($requrl=~/^\/adm\/wrapper\//) ||
-		($requrl=~m|^/adm/coursedocs/showdoc/|) ||
-		($requrl=~m|\.problem/smpedit$|) ||
-		($requrl=~/^\/public\/.*\/syllabus$/) ||
-                ($requrl=~/^\/adm\/(viewclasslist|navmaps)$/) ||
-                ($requrl=~/^\/adm\/.*\/aboutme\/portfolio(\?|$)/)) {
+            if ($check_symb) {
 # ------------------------------------- This is serious stuff, get symb and log
 		my $symb;
 		if ($query) {
@@ -603,9 +771,16 @@ sub handler {
 		}
 		if ($env{'form.symb'}) {
 		    $symb=&Apache::lonnet::symbclean($env{'form.symb'});
-		    if ($requrl =~ m|^/adm/wrapper/|
+		    if ($requrl eq '/adm/navmaps') {
+                        my ($map,$mid,$murl)=&Apache::lonnet::decode_symb($symb);
+                        &Apache::lonnet::symblist($map,$murl => [$murl,$mid]);
+		    } elsif ($requrl =~ m|^/adm/wrapper/|
 			|| $requrl =~ m|^/adm/coursedocs/showdoc/|) {
 			my ($map,$mid,$murl)=&Apache::lonnet::decode_symb($symb);
+                        if ($map =~ /\.page$/) {
+                            my $mapsymb = &Apache::lonnet::symbread($map);
+                            ($map,$mid,$murl)=&Apache::lonnet::decode_symb($mapsymb); 
+                        }
 			&Apache::lonnet::symblist($map,$murl => [$murl,$mid],
 						  'last_known' =>[$murl,$mid]);
 		    } elsif ((&Apache::lonnet::symbverify($symb,$requrl)) ||
@@ -614,6 +789,10 @@ sub handler {
                              (($requrl=~m|(.*/aboutme)/portfolio$|) &&
                               &Apache::lonnet::symbverify($symb,$1))) {
 			my ($map,$mid,$murl)=&Apache::lonnet::decode_symb($symb);
+                        if (($map =~ /\.page$/) && ($requrl !~ /\.page$/)) {
+                            my $mapsymb = &Apache::lonnet::symbread($map);
+                            ($map,$mid,$murl)=&Apache::lonnet::decode_symb($mapsymb);
+                        }
 			&Apache::lonnet::symblist($map,$murl => [$murl,$mid],
 						  'last_known' =>[$murl,$mid]);
 		    } else {
@@ -627,24 +806,68 @@ sub handler {
                     if ($requrl=~m{^(/adm/.*/aboutme)/portfolio$}) {
                         $requrl = $1;
                     }
-                    unless ($suppext) {
-		        $symb=&Apache::lonnet::symbread($requrl);
-		        if (&Apache::lonnet::is_on_map($requrl) && $symb &&
-			    !&Apache::lonnet::symbverify($symb,$requrl)) {
-			    $r->log_reason('Invalid symb for '.$requrl.': '.$symb);
-			    $env{'user.error.msg'}=
-			        "$requrl:bre:1:1:Invalid Access";
-			    return HTTP_NOT_ACCEPTABLE; 
-		        }
-		        if ($symb) {
-			    my ($map,$mid,$murl)=
-			        &Apache::lonnet::decode_symb($symb);
+		    $symb=&Apache::lonnet::symbread($requrl);
+                    if (&Apache::lonnet::is_on_map($requrl) && $symb) {
+                        my ($encstate,$invalidsymb);
+                        unless (&Apache::lonnet::symbverify($symb,$requrl,\$encstate)) {
+                            $invalidsymb = 1;
+                            #
+                            # If $env{'request.enc'} inconsistent with encryption expected for $symb
+                            # retrieved by lonnet::symbread(), call again to check for an instance of
+                            # $requrl in the course for which expected encryption matches request.enc.
+                            # If symb for different instance passes lonnet::symbverify(), use that as
+                            # the symb for $requrl and call &Apache::lonnet::allowed() for that symb.
+                            # Report invalid symb if there is no other symb. Redirect to /adm/ambiguous
+                            # if multiple possible symbs consistent with request.enc available for $requrl.
+                            #
+                            if (($env{'request.enc'} && !$encstate) || (!$env{'request.enc'} && $encstate)) {
+                                my %possibles;
+                                my $nocache = 1;
+                                my $oldsymb = $symb;
+                                $symb = &Apache::lonnet::symbread($requrl,'','','',\%possibles,$nocache);
+                                if (($symb) && ($symb ne $oldsymb)) {
+                                    if (&Apache::lonnet::symbverify($symb,$requrl)) {
+                                        my $access=&Apache::lonnet::allowed('bre',$requrl,$symb);
+                                        if ($access eq 'B') {
+                                            $env{'request.symb'} = $symb;
+                                            &Apache::blockedaccess::setup_handler($r);
+                                            return OK;
+                                        } elsif (($access eq '2') || ($access eq 'F')) {
+                                            $invalidsymb = '';
+                                        }
+                                    }
+                                } elsif (keys(%possibles) > 1) {
+                                    $r->internal_redirect('/adm/ambiguous');
+                                    return OK;
+                                }
+                            }
+                            if ($invalidsymb) {
+                                $r->log_reason('Invalid symb for '.$requrl.': '.$symb);
+                                $env{'user.error.msg'}=
+                                    "$requrl:bre:1:1:Invalid Access";
+                                return HTTP_NOT_ACCEPTABLE;
+                            }
+                        }
+                    }
+		    if ($symb) {
+			my ($map,$mid,$murl)=
+			    &Apache::lonnet::decode_symb($symb);
+                        if ($requrl eq '/adm/navmaps') {
+                            &Apache::lonnet::symblist($map,$murl =>[$murl,$mid]);
+                        } else {
+                            if (($map =~ /\.page$/) && ($requrl !~ /\.page$/)) {
+                                my $mapsymb = &Apache::lonnet::symbread($map);
+                                ($map,$mid,$murl)=&Apache::lonnet::decode_symb($mapsymb);
+                            }
 			    &Apache::lonnet::symblist($map,$murl =>[$murl,$mid],
 						      'last_known' =>[$murl,$mid]);
-		        }
+                        }
 		    }
 		}
 		$env{'request.symb'}=$symb;
+                if (($env{'request.symbread.cached.'}) && ($env{'request.symbread.cached.'} ne $symb)) {
+                    $env{'request.symbread.cached.'} = $symb;
+                }
 		&Apache::lonnet::courseacclog($symb);
 	    } else {
 # ------------------------------------------------------- This is other content
@@ -689,7 +912,8 @@ sub handler {
     }
 # ------------------------------------ See if this is a viewable portfolio file
     if (&Apache::lonnet::is_portfolio_url($requrl)) {
-	my $access=&Apache::lonnet::allowed('bre',$requrl);
+        my $clientip = $r->get_remote_host();
+        my $access=&Apache::lonnet::allowed('bre',$requrl,undef,undef,$clientip);
 	if ($access eq 'A') {
 	    &Apache::restrictedaccess::setup_handler($r);
 	    return OK;