--- loncom/auth/lonacc.pm	2020/10/01 12:43:10	1.159.2.8.2.5
+++ loncom/auth/lonacc.pm	2021/01/02 22:11:26	1.159.2.17
@@ -1,7 +1,7 @@
 # The LearningOnline Network
 # Cookie Based Access Handler
 #
-# $Id: lonacc.pm,v 1.159.2.8.2.5 2020/10/01 12:43:10 raeburn Exp $
+# $Id: lonacc.pm,v 1.159.2.17 2021/01/02 22:11:26 raeburn Exp $
 #
 # Copyright Michigan State University Board of Trustees
 #
@@ -355,14 +355,6 @@ sub sso_login {
 	    # 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'} =
@@ -550,7 +542,6 @@ sub handler {
             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'} = $expected;
@@ -572,62 +563,59 @@ sub handler {
         if ($env{'user.noloadbalance'} eq $r->dir_config('lonHostID')) {
             $checkexempt = 1;
         }
-        unless ($checkexempt) {
+        unless (($checkexempt) || (($requrl eq '/adm/switchserver') && (!$r->is_initial_req()))) {
             ($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 = $found_server;
-                    }
+                # Check if browser sent a LON-CAPA load balancer cookie (and this is a balancer)
+                my ($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 = $found_server;
+                }
+                unless ($requrl eq '/adm/switchserver') {
+                    $r->set_handlers('PerlResponseHandler'=>
+                                     [\&Apache::switchserver::handler]);
                 }
-            }
-        }
-        if ($is_balancer) {
-            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;
+                unless (($env{'form.origurl'}) || ($r->uri eq '/adm/roles') ||
+                        ($r->uri eq '/adm/switchserver') || ($r->uri eq '/adm/sso')) {
+                    $env{'form.origurl'} = $r->uri;
+                }
             }
         }
 
 # ---------------------------------------------------------------- Check access
 	my $now = time;
-        my $check_symb;
+        my ($check_symb,$check_access,$check_block,$access,$poss_symb);
 	if ($requrl !~ m{^/(?:adm|public|(?:prt|zip)spool)/}
 	    || $requrl =~ /^\/adm\/.*\/(smppg|bulletinboard)(\?|$ )/x) {
-            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/|) ||
-                    ($requrl=~m|\.problem/smpedit$|) ||
-                    ($requrl=~/^\/public\/.*\/syllabus$/) ||
-                    ($requrl=~/^\/adm\/(viewclasslist|navmaps)$/) ||
-                    ($requrl=~/^\/adm\/.*\/aboutme\/portfolio(\?|$)/)) {
-                    $check_symb = 1;
-                }
+            $check_access = 1;
+        }
+        if ((!$check_access) && ($env{'request.course.id'})) {
+            if (($requrl eq '/adm/viewclasslist') ||
+                ($requrl =~ m{^(/adm/wrapper|)\Q/uploaded/$cdom/$cnum/docs/\E}) ||
+                ($requrl =~ m{^/adm/.*/aboutme$}) ||
+                ($requrl=~m{^/adm/coursedocs/showdoc/})) {
+                $check_block = 1;
+            }
+        }
+        if (($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/|) ||
+                ($requrl=~m|\.problem/smpedit$|) ||
+                ($requrl=~/^\/public\/.*\/syllabus$/) ||
+                ($requrl=~/^\/adm\/(viewclasslist|navmaps)$/) ||
+                ($requrl=~/^\/adm\/.*\/aboutme\/portfolio(\?|$)/)) {
+                $check_symb = 1;
             }
+        }
+        if (($check_access) || ($check_block)) {
             if ($check_symb) {
                 if ($env{'form.symb'}) {
                     $poss_symb=&Apache::lonnet::symbclean($env{'form.symb'});
@@ -647,7 +635,9 @@ sub handler {
                 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))) {
+                    my $toplevelmap = $env{'course.'.$env{'request.course.id'}.'.url'};
+                    unless (($url eq $requrl) && (($possmap eq $toplevelmap) ||
+                                                  (&Apache::lonnet::is_on_map($possmap)))) {
                         undef($poss_symb);
                     }
                     if ($poss_symb) {
@@ -665,6 +655,18 @@ sub handler {
             } else {
                 $access=&Apache::lonnet::allowed('bre',$requrl);
             }
+        }
+        if ($check_block) {
+            if ($access eq 'B') {
+                if ($poss_symb) {
+                    if (&Apache::lonnet::symbverify($poss_symb,$requrl)) {
+                        $env{'request.symb'} = $poss_symb;
+                    }
+                }
+                &Apache::blockedaccess::setup_handler($r);
+                return OK;
+            }
+        } elsif ($check_access) { 
             if ($handle eq '') {
                 unless ($access eq 'F') {
                     if ($requrl =~ m{^/res/$match_domain/$match_username/}) {
@@ -682,9 +684,6 @@ sub handler {
 	    }
             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'} = $poss_symb;
                     }
@@ -798,19 +797,29 @@ sub handler {
                         unless (&Apache::lonnet::symbverify($symb,$requrl,\$encstate)) {
                             $invalidsymb = 1;
                             #
-                            # If $env{'request.enc'} is true, but no encryption for $symb retrieved
-                            # by original lonnet::symbread() call, call again to check for an instance
-                            # of $requrl in the course which has encryption, and set that as the symb.
-                            # If there is no such symb, or symbverify() fails for the new symb proceed
-                            # to report invalid symb.
+                            # 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'} && !$encstate) {
+                            if (($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) {
+                                if (($symb) && ($symb ne $oldsymb)) {
                                     if (&Apache::lonnet::symbverify($symb,$requrl)) {
-                                        $invalidsymb = '';
+                                        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');