File Coverage

blib/lib/Plack/Middleware/BlockHeaderInjection.pm

Criterion	Covered	Total	%
statement	33	33	100.0
branch	6	6	100.0
condition	1	2	50.0
subroutine	9	9	100.0
pod	1	2	50.0
total	50	52	96.1

package Plack::Middleware::BlockHeaderInjection;

# ABSTRACT: block header injections in responses

use v5.12;
use warnings;

use parent qw( Plack::Middleware );

use Plack::Util;
use Plack::Util::Accessor qw( logger status );

our $VERSION = 'v1.1.0';


sub call {
    my ( $self, $env ) = @_;

    # cache the logger
    $self->logger( $env->{'psgix.logger'} || sub { } )
      unless defined $self->logger;

    $self->status(500) unless $self->status;

    my $res = $self->app->($env);

    Plack::Util::response_cb(
        $res,
        sub {
            my $res = shift;

            # Sanity check headers

            my $hdrs = $res->[1];

            my $i = 0;
            while ( $i < @{$hdrs} ) {
                my $val = $hdrs->[ $i + 1 ];
                if ( $val =~ /[\n\r]/ ) {
                    my $key = $hdrs->[$i];
                    $self->log( error => "possible header injection detected in ${key}" );
                    $res->[0] = $self->status;
                    Plack::Util::header_remove( $hdrs, $key );
                }
                $i += 2;
            }

        }
    );

}

# Note: ideas borrowed from XSRFBlock


sub log {
    my ( $self, $level, $msg ) = @_;
    $self->logger->(
        {
            level   => $level,
            message => "BlockHeaderInjection: ${msg}",
        }
    );
}


1;

__END__