--- loncom/auth/lonacc.pm	2020/09/28 01:31:42	1.159.2.11
+++ loncom/auth/lonacc.pm	2020/10/23 21:33:46	1.159.2.15
@@ -1,7 +1,7 @@
 # The LearningOnline Network
 # Cookie Based Access Handler
 #
-# $Id: lonacc.pm,v 1.159.2.11 2020/09/28 01:31:42 raeburn Exp $
+# $Id: lonacc.pm,v 1.159.2.15 2020/10/23 21:33:46 raeburn Exp $
 #
 # Copyright Michigan State University Board of Trustees
 #
@@ -435,22 +435,6 @@ sub sso_login {
     return undef;
 }
 
-sub needs_symb_check {
-    my ($requrl) = @_;
-    $requrl=~/\.(\w+)$/;
-    if ((&Apache::loncommon::fileembstyle($1) eq 'ssi') ||
-        ($requrl=~/^\/adm\/.*\/(aboutme|smppg|bulletinboard)(\?|$ )/x) ||
-        ($requrl=~/^\/adm\/wrapper\//) ||
-        ($requrl=~m|^/adm/coursedocs/showdoc/|) ||
-        ($requrl=~m|\.problem/smpedit$|) ||
-        ($requrl=~/^\/public\/.*\/syllabus$/) ||
-        ($requrl=~/^\/adm\/(viewclasslist|navmaps)$/) ||
-        ($requrl=~/^\/adm\/.*\/aboutme\/portfolio(\?|$)/)) {
-        return 1;
-    }
-    return;
-}
-
 sub handler {
     my $r = shift;
     my $requrl=$r->uri;
@@ -545,6 +529,7 @@ sub handler {
                         if ($value =~ /^supplemental/) {
                             $suppext = 1;
                         }
+                        last;
                     }
                 }
             }
@@ -578,47 +563,64 @@ sub handler {
         if ($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'} = $r->uri;
+                unless (($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 $check_symb;
 	if ($requrl !~ m{^/(?:adm|public|(?:prt|zip)spool)/}
 	    || $requrl =~ /^\/adm\/.*\/(smppg|bulletinboard)(\?|$ )/x) {
             my ($access,$poss_symb);
-            if (($env{'request.course.id'}) && (!$suppext) && (&needs_symb_check($requrl))) {
-                unless ($env{'form.symb'}) {
-                    if ($r->args) {
-                        &Apache::loncommon::get_unprocessed_cgi($r->args,['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/|) ||
+                    ($requrl=~m|\.problem/smpedit$|) ||
+                    ($requrl=~/^\/public\/.*\/syllabus$/) ||
+                    ($requrl=~/^\/adm\/(viewclasslist|navmaps)$/) ||
+                    ($requrl=~/^\/adm\/.*\/aboutme\/portfolio(\?|$)/)) {
+                    $check_symb = 1;
                 }
+            }
+            if ($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);
@@ -715,7 +717,7 @@ 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;
@@ -725,7 +727,7 @@ sub handler {
 	if ($env{'request.course.id'}) {
 	    &Apache::lonnet::countacc($requrl);
             my $query=$r->args;
-            if (&needs_symb_check($requrl)) {
+            if ($check_symb) {
 # ------------------------------------- This is serious stuff, get symb and log
 		my $symb;
 		if ($query) {
@@ -768,54 +770,62 @@ sub handler {
                     if ($requrl=~m{^(/adm/.*/aboutme)/portfolio$}) {
                         $requrl = $1;
                     }
-                    unless ($suppext) {
-		        $symb=&Apache::lonnet::symbread($requrl);
-                        if (&Apache::lonnet::is_on_map($requrl) && $symb) {
-                            my ($encstate,$invalidsymb);
-                            unless (&Apache::lonnet::symbverify($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'} && !$encstate) {
-                                    my %possibles;
-                                    my $nocache = 1;
-                                    $symb = &Apache::lonnet::symbread($requrl,'','','',\%possibles,$nocache);
-                                    if ($symb) {
-                                        if (&Apache::lonnet::symbverify($symb,$requrl)) {
+		    $symb=&Apache::lonnet::symbread($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;
+                                } 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]);
+                    }
+		    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;