+our %is_whitelisted_component = (
+ # The RSS feed embeds an auth token in the path, but query
+ # information for the search. Because it's a straight-up read, in
+ # addition to embedding its own auth, it's fine.
+ '/NoAuth/rss/dhandler' => 1,
+
+ # IE doesn't send referer in window.open()
+ # besides, as a harmless calendar select page, it's fine
+ '/Helpers/CalPopup.html' => 1,
+
+ # While both of these can be used for denial-of-service against RT
+ # (construct a very inefficient query and trick lots of users into
+ # running them against RT) it's incredibly useful to be able to link
+ # to a search result or bookmark a result page.
+ '/Search/Results.html' => 1,
+ '/Search/Simple.html' => 1,
+);
+
+# Components which are blacklisted from automatic, argument-based whitelisting.
+# These pages are not idempotent when called with just an id.
+our %is_blacklisted_component = (
+ # Takes only id and toggles bookmark state
+ '/Helpers/Toggle/TicketBookmark' => 1,
+);
+
+sub IsCompCSRFWhitelisted {
+ my $comp = shift;
+ my $ARGS = shift;
+
+ return 1 if $is_whitelisted_component{$comp};
+
+ my %args = %{ $ARGS };
+
+ # If the user specifies a *correct* user and pass then they are
+ # golden. This acts on the presumption that external forms may
+ # hardcode a username and password -- if a malicious attacker knew
+ # both already, CSRF is the least of your problems.
+ my $AllowLoginCSRF = not RT->Config->Get('RestrictReferrerLogin');
+ if ($AllowLoginCSRF and defined($args{user}) and defined($args{pass})) {
+ my $user_obj = RT::CurrentUser->new();
+ $user_obj->Load($args{user});
+ return 1 if $user_obj->id && $user_obj->IsPassword($args{pass});
+
+ delete $args{user};
+ delete $args{pass};
+ }
+
+ # Some pages aren't idempotent even with safe args like id; blacklist
+ # them from the automatic whitelisting below.
+ return 0 if $is_blacklisted_component{$comp};
+
+ # Eliminate arguments that do not indicate an effectful request.
+ # For example, "id" is acceptable because that is how RT retrieves a
+ # record.
+ delete $args{id};
+
+ # If they have a valid results= from MaybeRedirectForResults, that's
+ # also fine.
+ delete $args{results} if $args{results}
+ and $HTML::Mason::Commands::session{"Actions"}->{$args{results}};
+
+ # The homepage refresh, which uses the Refresh header, doesn't send
+ # a referer in most browsers; whitelist the one parameter it reloads
+ # with, HomeRefreshInterval, which is safe
+ delete $args{HomeRefreshInterval};
+
+ # If there are no arguments, then it's likely to be an idempotent
+ # request, which are not susceptible to CSRF
+ return 1 if !%args;
+
+ return 0;
+}
+
+sub IsRefererCSRFWhitelisted {
+ my $referer = _NormalizeHost(shift);
+ my $base_url = _NormalizeHost(RT->Config->Get('WebBaseURL'));
+ $base_url = $base_url->host_port;
+
+ my $configs;
+ for my $config ( $base_url, RT->Config->Get('ReferrerWhitelist') ) {
+ push @$configs,$config;
+ return 1 if $referer->host_port eq $config;
+ }
+
+ return (0,$referer,$configs);
+}
+
+=head3 _NormalizeHost
+
+Takes a URI and creates a URI object that's been normalized
+to handle common problems such as localhost vs 127.0.0.1
+
+=cut
+
+sub _NormalizeHost {
+
+ my $uri= URI->new(shift);
+ $uri->host('127.0.0.1') if $uri->host eq 'localhost';
+
+ return $uri;
+
+}
+
+sub IsPossibleCSRF {
+ my $ARGS = shift;
+
+ # If first request on this session is to a REST endpoint, then
+ # whitelist the REST endpoints -- and explicitly deny non-REST
+ # endpoints. We do this because using a REST cookie in a browser
+ # would open the user to CSRF attacks to the REST endpoints.
+ my $comp = $HTML::Mason::Commands::m->request_comp->path;
+ $HTML::Mason::Commands::session{'REST'} = $comp =~ m{^/REST/\d+\.\d+/}
+ unless defined $HTML::Mason::Commands::session{'REST'};
+
+ if ($HTML::Mason::Commands::session{'REST'}) {
+ return 0 if $comp =~ m{^/REST/\d+\.\d+/};
+ my $why = <<EOT;
+This login session belongs to a REST client, and cannot be used to
+access non-REST interfaces of RT for security reasons.
+EOT
+ my $details = <<EOT;
+Please log out and back in to obtain a session for normal browsing. If
+you understand the security implications, disabling RT's CSRF protection
+will remove this restriction.
+EOT
+ chomp $details;
+ HTML::Mason::Commands::Abort( $why, Details => $details );
+ }
+
+ return 0 if IsCompCSRFWhitelisted( $comp, $ARGS );
+
+ # if there is no Referer header then assume the worst
+ return (1,
+ "your browser did not supply a Referrer header", # loc
+ ) if !$ENV{HTTP_REFERER};
+
+ my ($whitelisted, $browser, $configs) = IsRefererCSRFWhitelisted($ENV{HTTP_REFERER});
+ return 0 if $whitelisted;
+
+ if ( @$configs > 1 ) {
+ return (1,
+ "the Referrer header supplied by your browser ([_1]) is not allowed by RT's configured hostname ([_2]) or whitelisted hosts ([_3])", # loc
+ $browser->host_port,
+ shift @$configs,
+ join(', ', @$configs) );
+ }
+
+ return (1,
+ "the Referrer header supplied by your browser ([_1]) is not allowed by RT's configured hostname ([_2])", # loc
+ $browser->host_port,
+ $configs->[0]);
+}
+
+sub ExpandCSRFToken {
+ my $ARGS = shift;
+
+ my $token = delete $ARGS->{CSRF_Token};
+ return unless $token;
+
+ my $data = $HTML::Mason::Commands::session{'CSRF'}{$token};
+ return unless $data;
+ return unless $data->{uri} eq $HTML::Mason::Commands::r->uri;
+
+ my $user = $HTML::Mason::Commands::session{'CurrentUser'}->UserObj;
+ return unless $user->ValidateAuthString( $data->{auth}, $token );
+
+ %{$ARGS} = %{$data->{args}};
+
+ # We explicitly stored file attachments with the request, but not in
+ # the session yet, as that would itself be an attack. Put them into
+ # the session now, so they'll be visible.
+ if ($data->{attach}) {
+ my $filename = $data->{attach}{filename};
+ my $mime = $data->{attach}{mime};
+ $HTML::Mason::Commands::session{'Attachments'}{$filename}
+ = $mime;
+ }
+
+ return 1;
+}
+
+sub StoreRequestToken {
+ my $ARGS = shift;
+
+ my $token = Digest::MD5::md5_hex(time . {} . $$ . rand(1024));
+ my $user = $HTML::Mason::Commands::session{'CurrentUser'}->UserObj;
+ my $data = {
+ auth => $user->GenerateAuthString( $token ),
+ uri => $HTML::Mason::Commands::r->uri,
+ args => $ARGS,
+ };
+ if ($ARGS->{Attach}) {
+ my $attachment = HTML::Mason::Commands::MakeMIMEEntity( AttachmentFieldName => 'Attach' );
+ my $file_path = delete $ARGS->{'Attach'};
+ $data->{attach} = {
+ filename => Encode::decode_utf8("$file_path"),
+ mime => $attachment,
+ };
+ }
+
+ $HTML::Mason::Commands::session{'CSRF'}->{$token} = $data;
+ $HTML::Mason::Commands::session{'i'}++;
+ return $token;
+}
+
+sub MaybeShowInterstitialCSRFPage {
+ my $ARGS = shift;
+
+ return unless RT->Config->Get('RestrictReferrer');
+
+ # Deal with the form token provided by the interstitial, which lets
+ # browsers which never set referer headers still use RT, if
+ # painfully. This blows values into ARGS
+ return if ExpandCSRFToken($ARGS);
+
+ my ($is_csrf, $msg, @loc) = IsPossibleCSRF($ARGS);
+ return if !$is_csrf;
+
+ $RT::Logger->notice("Possible CSRF: ".RT::CurrentUser->new->loc($msg, @loc));
+
+ my $token = StoreRequestToken($ARGS);
+ $HTML::Mason::Commands::m->comp(
+ '/Elements/CSRF',
+ OriginalURL => $HTML::Mason::Commands::r->uri,
+ Reason => HTML::Mason::Commands::loc( $msg, @loc ),
+ Token => $token,
+ );
+ # Calls abort, never gets here
+}
+
+our @POTENTIAL_PAGE_ACTIONS = (
+ qr'/Ticket/Create.html' => "create a ticket", # loc
+ qr'/Ticket/' => "update a ticket", # loc
+ qr'/Admin/' => "modify RT's configuration", # loc
+ qr'/Approval/' => "update an approval", # loc
+ qr'/Dashboards/' => "modify a dashboard", # loc
+ qr'/m/ticket/' => "update a ticket", # loc
+ qr'Prefs' => "modify your preferences", # loc
+ qr'/Search/' => "modify or access a search", # loc
+ qr'/SelfService/Create' => "create a ticket", # loc
+ qr'/SelfService/' => "update a ticket", # loc
+);
+
+sub PotentialPageAction {
+ my $page = shift;
+ my @potentials = @POTENTIAL_PAGE_ACTIONS;
+ while (my ($pattern, $result) = splice @potentials, 0, 2) {
+ return HTML::Mason::Commands::loc($result)
+ if $page =~ $pattern;
+ }
+ return "";
+}
+