File Coverage

blib/lib/HTTP/Session2/ClientStore2.pm

Criterion	Covered	Total	%
statement	90	117	76.9
branch	6	20	30.0
condition	3	3	100.0
subroutine	21	24	87.5
pod	1	7	14.2
total	121	171	70.7

package HTTP::Session2::ClientStore2;
use strict;
use warnings;
use utf8;
use 5.008_001;

use Cookie::Baker ();
use Storable ();
use MIME::Base64 ();
use Digest::HMAC ();
use HTTP::Session2::Expired;
use HTTP::Session2::Random;
use Data::MessagePack;
use Crypt::CBC;

use Mouse;

extends 'HTTP::Session2::Base';

our $MESSAGE_PACK = Data::MessagePack->new();

has serializer => (
    is => 'ro',
    default => sub {
        sub {
            $MESSAGE_PACK->pack($_[0]);
        }
    },
);

has deserializer => (
    is => 'ro',
    default => sub {
        sub {
            $MESSAGE_PACK->unpack($_[0])
        }
    },
);

has cipher => (
    is => 'ro',
    isa => 'Crypt::CBC',
    required => 1,
);

has ignore_old => (
    is => 'ro',
);

no Mouse;

# HMAC timing attack
sub _compare {
    my ( $s1, $s2 ) = @_;

    return unless defined $s2;
    return if length $s1 != length $s2;
    my $r = 0;
    for my $i ( 0 .. length($s1) - 1 ) {
        $r |= ord( substr $s1, $i ) ^ ord( substr $s2, $i );
    }

    return $r == 0;
}

sub sig {
    my($self, $b64) = @_;
    $self->secret or die "Missing secret. ABORT";
    Digest::HMAC::hmac_hex($b64, $self->secret, $self->hmac_function);
}

sub load_session {
    my $self = shift;

    # Load from cookie.
    my $cookies = Cookie::Baker::crush_cookie($self->env->{HTTP_COOKIE});
    my $session_cookie = $cookies->{$self->session_cookie->{name}};
    if (defined $session_cookie) {
        my $textified = $session_cookie;
        my $encrypted = MIME::Base64::decode_base64url($textified);
        my $serialized_and_sig = eval { $self->cipher->decrypt($encrypted) };
        if ($@) {
            warn $@;
            return;
        }
        my ($sig, $serialized) = $self->_deserialize($serialized_and_sig);
        _compare($self->sig($serialized), $sig) or do {
            return;
        };
        my ($time, $id, $data) = $self->_deserialize($serialized);

        if (defined $self->ignore_old) {
            if ($time < $self->ignore_old()) {
                return;
            }
        }

        $self->{id}    = $id;
        $self->{_data} = $data;
        return 1;
    }
}

sub create_session {
    my $self = shift;

    $self->{id}    = HTTP::Session2::Random::generate_session_id();
    $self->{_data} = +{};
}

sub regenerate_id {
    my ($self) = @_;

    # Load original session first.
    $self->load_session();

    # Create new session.
    $self->{id}    = HTTP::Session2::Random::generate_session_id();
    $self->is_dirty(1);
    $self->necessary_to_send(1);
}

sub xsrf_token {
    my $self = shift;
    return $self->id;
}

sub expire {
    my $self = shift;

    # Load original session first.
    $self->load_session();

    # Rebless to expired object.
    bless $self, 'HTTP::Session2::Expired';

    return;
}

sub finalize {
    my ($self) = @_;

    return () unless $self->necessary_to_send || $self->is_dirty;

    my @cookies;

    # Finalize session cookie
    {
        my %cookie = %{$self->session_cookie};
        my $name = delete $cookie{name};
        my $value = $self->_serialize($self->id, $self->_data);
        push @cookies, $name => +{
            %cookie,
            value => $value,
        };
    }

    # Finalize XSRF cookie
    {
        my %cookie = %{$self->xsrf_cookie};
        my $name = delete $cookie{name};
        push @cookies, $name => +{
            %cookie,
            value => $self->id,
        };
    }

    return @cookies;
}

sub _serialize {
    my ($self, $id, $data) = @_;

    my $serialized = $self->serializer->([time(), $id, $data]);
    my $sig = $self->sig($serialized);
    my $joined = $self->serializer->([$sig, $serialized]);
    my $encrypted = $self->cipher->encrypt($joined);
    $encrypted = MIME::Base64::encode_base64url($encrypted);
    return $encrypted;
}

sub _deserialize {
    my ($self, $serialized) = @_;

    my @data;
    eval {
        @data = @{$self->deserializer->($serialized)};
    };
    if ($@) {
        warn "Can't deserialize session data. It seems that the browser sent strange or incompatible cookies.";
    }

    @data;
}

1;
__END__