From 2cc2bcd02ba39b7112ee5428f39bdac95e6fd1f3 Mon Sep 17 00:00:00 2001
From: Ian Jackson <ijackson@chiark.greenend.org.uk>
Date: Thu, 7 Mar 2013 18:09:41 +0000
Subject: [PATCH] javascript hijacking fix, docs are still wip

---
 caf.pod              | 27 +++++++++++++++++++++++++++
 cgi-auth-flexible.pm | 42 +++++++++++++++++++++++++++++++++---------
 2 files changed, 60 insertions(+), 9 deletions(-)

diff --git a/caf.pod b/caf.pod
index 8e2d193..2603499 100644
--- a/caf.pod
+++ b/caf.pod
@@ -85,6 +85,33 @@ generate the whole HTML C<< <input...> >> element.
 
 Do not put the secret value in URLs for C<GET> requests.
 
+=head2 NON-PAGE RESOURCES
+
+Some, but not all, non-page resources (fetched with GET) need to have
+the secret hidden parameter in the query parameters in the form url.
+
+So if your application supports anything except HTML pages you need to
+take special measures.  (Wholly invariant resources which don't depend
+on which user is logged in are an exception.)
+
+When you generate a url to such a resource you must call
+resource_get_needs_secret_hidden to find out whether to include the
+hidden form parameter  xxx fixme
+
+You can only when logged in
+
+ call
+C<nonpage_ok> when you are processing one of these.  You need to
+supply a parameter specifying exactly what kind of resource this is:
+
+
+
+before you
+generate any output 
+
+ (other than
+
+
 =head2 MUTATING OPERATIONS AND EXTERNAL LINKS INTO YOUR SITE
 
 By default CGI::Auth::Flexible does not permit external links into
diff --git a/cgi-auth-flexible.pm b/cgi-auth-flexible.pm
index 8517f3b..eea4bc0 100644
--- a/cgi-auth-flexible.pm
+++ b/cgi-auth-flexible.pm
@@ -17,8 +17,6 @@
 # You should have received a copy of the GNU Affero General Public License
 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
-die "need to fix js hijacking";
-
 use strict;
 use warnings FATAL => 'all';
 
@@ -181,8 +179,9 @@ sub gen_plain_login_link ($$) {
 sub gen_srcdump_link_html ($$$$) {
     my ($c,$r,$anchor,$specval) = @_;
     my %params = ($r->{S}{srcdump_param_name} => [ $specval ]);
-    return '<a href="'.escapeHTML($r->url_with_query_params(\%params)).'">'.
-	$anchor."</a>";
+    return '<a href="'.
+	escapeHTML($r->url_with_query_params(\%params,'SRCDUMP')).
+	'">'.$anchor."</a>";
 }
 sub gen_plain_licence_link_html ($$) {
     my ($c,$r) = @_;
@@ -668,9 +667,9 @@ my @ca = (-name => $r->{S}{cookie_name},
 
 # pages/param-sets are
 #   n normal non-mutating page
-#   r retrieval of information for JS, non-mutating
+#   r retrieval of information for JS etc., non-mutating
 #   m mutating page
-#   u update of information by JS, mutating
+#   u update of information by JS etc., mutating
 #   i login
 #   o logout
 #   O "you have just logged out" page load
@@ -907,6 +906,7 @@ sub _check_divert_core ($) {
         die unless $parmt eq 'y';
         die unless $cookh eq $parmh;
     }
+    $r->{ParmT} = $parmt;
     $r->{AssocSecret} = $cooks;
     $r->{UserOK} = $cooku;
 #print STDERR "C-D-C OK\n";
@@ -1036,12 +1036,17 @@ sub get_username ($) {
     return $r->{UserOK};
 }
 
-sub url_with_query_params ($$) {
-    my ($r, $params) = @_;
+sub url_with_query_params ($$;$) {
+    my ($r, $params, $nonpagetype) = @_;
 #print STDERR "PARAMS ",Dumper($params);
     my $uri = URI->new($r->_ch('get_url'));
     $uri->path($uri->path() . $params->{''}[0]) if $params->{''};
-    $uri->query_form(flatten_params($params));
+    my @flatparams = flatten_params($params);
+    if (defined $nonpagetype
+	&& $r->nonpage_get_needs_secret_hidden($nonpagetype)) {
+	push @flatparams, $r->{S}{assoc_param_name}, $r->secret_hidden_val();
+    }
+    $uri->query_form(@flatparams);
     return $uri->as_string();
 }
 
@@ -1288,6 +1293,25 @@ sub mutate_ok ($) {
     return $r->_is_post();
 }
 
+our %_resource_get_needs_secret_hidden =
+    (map { $_ => 0 } qw(PAGE FRAME IFRAME SRCDUMP STYLESHEET FAVICON),
+     map { $_ => 1 } qw(IMAGE SCRIPT AJAX-XML AJAX-JSON AJAX-OTHER));
+
+sub resource_get_needs_secret_hidden ($) {
+    my ($r, $nonpagetype) = @_;
+    my $ent = $_resource_get_needs_secret_hidden{$nonpagetype};
+    die "unsupported nonpage GET type $nonpagetype" unless defined $ent;
+    return $ent;
+}
+
+sub nonpage_ok ($$) {
+    my ($r, $nonpagetype) = @_;
+    $r->_assert_checked();
+    return unless $r->resource_get_needs_secret_hidden($nonpagetype);
+    return if $r->{ParmT};
+    die "missing hidden secret parameter on nonpage GET $nonpagetype";
+}
+
 #---------- output ----------
 
 sub secret_cookie_val ($) {
-- 
2.30.2