From: Matt Simerson <m...@tnpi.net> --- plugins/sender_permitted_from | 163 ++++++++++++++++++++++------------------- 1 files changed, 87 insertions(+), 76 deletions(-)
diff --git a/plugins/sender_permitted_from b/plugins/sender_permitted_from index 287847e..dbccf22 100644 --- a/plugins/sender_permitted_from +++ b/plugins/sender_permitted_from @@ -5,28 +5,37 @@ SPF - plugin to implement Sender Permitted From =head1 SYNOPSIS - # in config/plugins - sender_permitted_from +Prevents email sender address spoofing by checking the SPF policy of the purported senders domain. -Or if you wish to issue 5xx on SPF fail: +=head1 DESCRIPTION - sender_permitted_from spf_deny 1 +Sender Policy Framework (SPF) is an e-mail validation system designed to prevent spam by addressing source address spoofing. SPF allows administrators to specify which hosts are allowed to send e-mail from a given domain by creating a specific SPF record in the public DNS. Mail exchangers then use the DNS to check that mail from a given domain is being sent by a host sanctioned by that domain's administrators. -- http://en.wikipedia.org/wiki/Sender_Policy_Framework + +=head1 CONFIGURATION -Other arguments are 'trust 0' and 'guess 0'. These turn off processing of -spf.trusted-forwarders.org and the best_guess functionality. It is unlikely -that you want to turn these off. +In config/plugins, add arguments to the sender_permitted_from line. -Adding 'spf_deny 2' will also issue a 5xx on a softfail response. + sender_permitted_from spf_deny 1 -You can also specify local SPF policy with +=head2 spf_deny - include '<spf mechanism list>' +Setting spf_deny to 0 will prevent emails from being rejected, even if they fail SPF checks. sfp_deny 1 is the default, and a reasonable setting. It temporarily defers connections (4xx) that have soft SFP failures and only rejects (5xx) messages when the sending domains policy suggests it. Settings spf_deny to 2 is more aggressive and will cause soft failures to be rejected permanently. See also http://spf.pobox.com/ +=head1 AUTHOR + +Matt Simerson <msimer...@cpan.org> + +=head1 ACKNOWLEDGEMENTS + +whomever wrote the original SPF plugin, upon which I based this. + =cut -use Mail::SPF::Query 1.991; +use strict; +use Mail::SPF 2.000; +use Data::Dumper; sub register { my ($self, $qp, @args) = @_; @@ -34,40 +43,55 @@ sub register { } sub hook_mail { - my ($self, $transaction, $sender, %param) = @_; - - return (DECLINED) unless ($sender->format ne "<>" - and $sender->host && $sender->user); - - # If we are receving from a relay permitted host, then we are probably - # not the delivery system, and so we shouldn't check - - return (DECLINED) if $self->qp->connection->relay_client(); - my @relay_clients = $self->qp->config("relayclients"); - my $more_relay_clients = $self->qp->config("morerelayclients", "map"); - my %relay_clients = map { $_ => 1 } @relay_clients; - my $client_ip = $self->qp->connection->remote_ip; - while ($client_ip) { - return (DECLINED) if exists $relay_clients{$client_ip}; - return (DECLINED) if exists $more_relay_clients->{$client_ip}; - $client_ip =~ s/\d+\.?$//; # strip off another 8 bits - } - - my $host = lc $sender->host; - my $from = $sender->user . '@' . $host; - - my $ip = $self->qp->connection->remote_ip; - my $helo = $self->qp->connection->hello_host; - - my $query = Mail::SPF::Query->new(ip => $ip, sender => $from, helo => $helo, - sanitize => 1, - local => $self->{_args}{local}, - guess => defined($self->{_args}{guess}) ? $self->{_args}{guess} : 1, - trusted => defined($self->{_args}{trust}) ? $self->{_args}{trust} : 1) - || die "Couldn't construct Mail::SPF::Query object"; - $transaction->notes('spfquery', $query); - - return (DECLINED); + my ($self, $transaction, $sender, %param) = @_; + + my $format = $sender->format; + my $host = lc $sender->host; + my $user = $sender->user; + my $client_ip = $self->qp->connection->remote_ip; + my $from = $sender->user . '@' . $host; + my $helo = $self->qp->connection->hello_host; + + return (DECLINED, "SPF - null sender") unless ($format ne "<>" && $host && $user); + + # If we are receving from a relay permitted host, then we are probably + # not the delivery system, and so we shouldn't check + return (DECLINED, "SPF - relaying permitted") if $self->qp->connection->relay_client(); + + my @relay_clients = $self->qp->config("relayclients"); + my $more_relay_clients = $self->qp->config("morerelayclients", "map"); + my %relay_clients = map { $_ => 1 } @relay_clients; + while ($client_ip) { + return (DECLINED, "SPF - relaying permitted") if exists $relay_clients{$client_ip}; + return (DECLINED, "SPF - relaying permitted") if exists $more_relay_clients->{$client_ip}; + $client_ip =~ s/\d+\.?$//; # strip off another 8 bits + } + + my $scope = $from ? 'mfrom' : 'helo'; + $client_ip = $self->qp->connection->remote_ip; + my %req_params = ( + versions => [1, 2], # optional + scope => $scope, + ip_address => $client_ip, + ); + + if ( $scope =~ /mfrom|pra/ ) { + $req_params{identity} = $from; + $req_params{helo_identity} = $helo if $helo; + } + elsif ( $scope eq 'helo' ) { + $req_params{identity} = $helo; + $req_params{helo_identity} = $helo; + }; + + my $spf_server = Mail::SPF::Server->new(); + my $request = Mail::SPF::Request->new( %req_params ); + my $result = $spf_server->process($request); + + $transaction->notes('spfquery', $result); + + return (OK) if $result->code eq 'pass'; # this test passed + return (DECLINED, "SPF - $result->code"); } sub hook_rcpt { @@ -76,47 +100,34 @@ sub hook_rcpt { # special addresses don't get SPF-tested. return DECLINED if $rcpt and $rcpt->user and $rcpt->user =~ /^(?:postmaster|abuse|mailer-daemon|root)$/i; - my $query = $transaction->notes('spfquery'); - - return DECLINED if !$query; - my ($result, $smtp_comment, $comment) = $query->result2($rcpt->address); - - if ($result eq "error") { - return (DENYSOFT, "SPF error: $smtp_comment"); - } - - if ($result eq "fail" and $self->{_args}{spf_deny}) { - return (DENY, "SPF forgery: $smtp_comment"); - } - - if ($result eq "softfail" and $self->{_args}{spf_deny} > 1) { - return (DENY, "SPF probable forgery: $smtp_comment"); + my $result = $transaction->notes('spfquery') or return DECLINED; + my $code = $result->code; + my $why = $result->local_explanation; + my $deny = $self->{_args}{spf_deny}; + + return ( DECLINED, "SPF - $code: $why") if $code eq "pass"; + return ( DECLINED, "SPF - $code, $why") if ! $deny; + return ( DENYSOFT, "SPF - $code: $why") if $code eq "error"; + return ( DENY, "SPF - forgery: $why") if $code eq 'fail'; + + if ($code eq "softfail" ) { + return (DENY, "SPF probable forgery: $why") if $deny > 1; + return (DENYSOFT, "SPF probable forgery: $why"); } - if ($result eq 'fail' or $result eq 'softfail') { - $self->log(LOGDEBUG, "result for $rcpt->address was $result: $comment"); - } + $self->log(LOGDEBUG, "result for $rcpt->address was $code: $why"); - return DECLINED; -} - -sub _uri_escape { - my $str = shift; - $str =~ s/([^A-Za-z0-9\-_.!~*\'()])/sprintf "%%%X", ord($1)/eg; - return $str; + return ( DECLINED, "SPF - $code, $why"); } sub hook_data_post { my ($self, $transaction) = @_; - my $query = $transaction->notes('spfquery'); - return DECLINED if !$query; - - my ($result, $smtp_comment, $comment) = $query->message_result2(); + my $result = $transaction->notes('spfquery') or return DECLINED; - $self->log(LOGDEBUG, "result was $result: $comment") if ($result); + $self->log(LOGDEBUG, "result was $result->code"); - $transaction->header->add('Received-SPF' => "$result ($comment)", 0); + $transaction->header->add('Received-SPF' => $result->received_spf_header, 0); return DECLINED; } -- 1.7.0.6
