added Authentication-Results header, with provider

dkim, dmarc, fcrdns (iprev), spf, and smtp-auth

lib/Qpsmtpd/Plugin.pm

@@ -271,6 +271,34 @@ sub store_deferred_reject {
     return (DECLINED);
 }
 
+sub store_auth_results {
+    my ($self, $value) = @_;
+
+    my @headers = $self->transaction->header->get('Authentication-Results');
+    chomp @headers;
+    my @deleteme;
+    for ( my $i = 0; $i < scalar @headers; $i++ ) {
+        my @values = split /;/, $headers[$i];
+        if ( $self->config->('me') ne $values[0] ) {  # some other MTA
+# we generally want to remove Authentication-Results headers added by other
+# MTAs (so our downstream can trust the A-R header we insert), but we also
+# don't want to invalidate DKIM signatures.
+# TODO: parse the DKIM signature(s) to see if A-R header is signed
+            if ( ! $self->transaction->header->get('DKIM-Signature') ) {
+                $self->log(LOGINFO, "deleted auth-results from $_");
+                push @deleteme, $i;
+            };
+            next;
+        };
+        push @values, $value;
+        $self->log(LOGINFO, "appended to auth-results: $value");
+        $self->transaction->header->replace('Authentication->Results', join('; ', @values ), $i);
+    }
+    foreach ( @deleteme ) {
+        $self->transaction->header->delete('Authentication-Results', $_);
+    };
+};
+
 sub init_resolver {
     my $self = shift;
     my $timeout = $self->{_args}{dns_timeout} || shift || 5;

lib/Qpsmtpd/SMTP.pm

@@ -770,6 +770,7 @@ sub data_respond {
     my $esmtp      = substr($smtp, 0, 1) eq "E";
     my $authheader = '';
     my $sslheader  = '';
+    my $auth_result = 'none';
 
     if (defined $self->connection->notes('tls_enabled')
         and $self->connection->notes('tls_enabled'))
@@ -780,15 +781,28 @@ sub data_respond {
           . " encrypted) ";
     }
 
-    if (defined $self->{_auth} and $self->{_auth} == OK) {
+    if (defined $self->{_auth} ) {
-        $smtp .= "A" if $esmtp;    # RFC3848
+        my $mech = $self->{_auth_mechanism};
-        $authheader =
+        my $user = $self->{_auth_user};
-"(smtp-auth username $self->{_auth_user}, mechanism $self->{_auth_mechanism})\n";
+        $auth_result = "auth=";
+        if ( $self->{_auth} == OK) {
+            $smtp .= "A" if $esmtp;    # RFC3848
+            $authheader = "(smtp-auth username $user, mechanism $mech)\n";
+            $auth_result .= 'pass';
+        }
+        else {
+            $auth_result .= 'fail';
+        };
+        $auth_result .= " ($mech) smtp.auth=$user";
     }
 
-    $header->add("Received",
+    $header->add('Received',
                  $self->received_line($smtp, $authheader, $sslheader), 0);
 
+    # RFC 5451: used in AUTH, DKIM, DOMAINKEYS, SENDERID, SPF
+    $header->add('Authentication-Results',
+                join('; ', $self->config('me'), $auth_result ) );
+
     # if we get here without seeing a terminator, the connection is
     # probably dead.
     unless ($complete) {

plugins/dkim

@@ -222,6 +222,9 @@ sub validate_it {
     my $result = $dkim->result;
     my $mess   = $self->get_details($dkim);
 
+    $self->store_auth_results("dkim=" .$dkim->result_detail . " header.i=@".$dkim->signature->domain);
+    #$self->add_header($mess);
+
     foreach my $t (qw/ pass fail invalid temperror none /) {
         next if $t ne $result;
         my $handler = 'handle_sig_' . $t;
@@ -286,8 +289,7 @@ sub handle_sig_fail {
     my ($self, $dkim, $mess) = @_;
 
     $self->adjust_karma(-1);
-    return
+    return $self->get_reject("signature invalid: " . $dkim->result_detail,
-      $self->get_reject("DKIM signature invalid: " . $dkim->result_detail,
                         $mess);
 }
 
@@ -316,12 +318,10 @@ sub handle_sig_invalid {
     $self->log(LOGINFO, $mess);
 
     if ($prs->{accept}) {
-        $self->add_header($mess);
         $self->log(LOGERROR, "error, invalid signature but accept policy!?");
         return DECLINED;
     }
     elsif ($prs->{neutral}) {
-        $self->add_header($mess);
         $self->log(LOGERROR, "error, invalid signature but neutral policy?!");
         return DECLINED;
     }
@@ -333,7 +333,6 @@ sub handle_sig_invalid {
 
     # this should never happen
     $self->log(LOGINFO, "error, invalid signature, unhandled");
-    $self->add_header($mess);
     return DECLINED;
 }
 
@@ -527,8 +526,6 @@ sub get_selector {
 sub add_header {
     my $self = shift;
     my $header = shift or return;
-
-    # consider adding Authentication-Results header, (RFC 5451)
     $self->qp->transaction->header->add('X-DKIM-Authentication', $header, 0);
 }
 

plugins/dmarc

@@ -122,24 +122,31 @@ sub data_post_handler {
     #       evaluation returned a "pass" result.
     my $spf_dom = $transaction->notes('spf_pass_host');
 
+    my $effective_policy = ( $self->{_args}{is_subdomain} && defined $policy->{sp} )
+        ? $policy->{sp} : $policy->{p};
+
     #   5.  Conduct identifier alignment checks.
-    return DECLINED
+    if ( $self->is_aligned($from_dom, $org_dom, $policy, $spf_dom ) ) {
-        if $self->is_aligned($from_dom, $org_dom, $policy, $spf_dom );
+        $self->store_auth_results("dmarc=pass (p=$effective_policy) d=$from_dom");
+        return DECLINED;
+    };
 
     #   6.  Apply policy.  Emails that fail the DMARC mechanism check are
     #       disposed of in accordance with the discovered DMARC policy of the
     #       Domain Owner.  See Section 6.2 for details.
-    if ( $self->{_args}{is_subdomain} && defined $policy->{sp} ) {
+    if ( lc $effective_policy eq 'none' ) {
-        return DECLINED if lc $policy->{sp} eq 'none';
+        $self->store_auth_results("dmarc=fail (p=none) d=$from_dom");
+        return DECLINED;
     };
-    return DECLINED if lc $policy->{p} eq 'none';
 
     my $pct = $policy->{pct} || 100;
     if ( $pct != 100 && int(rand(100)) >= $pct ) {
         $self->log("fail, tolerated, policy, sampled out");
+        $self->store_auth_results("dmarc=sampled_out (p=$effective_policy) d=$from_dom");
         return DECLINED;
     };
 
+    $self->store_auth_results("dmarc=fail (p=$effective_policy) d=$from_dom");
     return $self->get_reject("failed DMARC policy");
 }
 

plugins/fcrdns

@@ -6,7 +6,7 @@ Forward Confirmed RDNS - http://en.wikipedia.org/wiki/FCrDNS
 
 =head1 DESCRIPTION
 
-Determine if the SMTP sender has matching forward and reverse DNS. 
+Determine if the SMTP sender has matching forward and reverse DNS.
 
 Sets the connection note fcrdns.
 
@@ -88,6 +88,38 @@ From Wikipedia summary:
 
 3. Any A or AAAA record returned by the second query is then compared against the original IP address (check_ip_match), and if there is a match, then the FCrDNS check passes.
 
+=head1 iprev
+
+# https://www.ietf.org/rfc/rfc5451.txt
+
+2.4.3.  "iprev" Results
+
+The result values are used by the "iprev" method, defined in
+Section 3, are as follows:
+
+pass:  The DNS evaluation succeeded, i.e., the "reverse" and
+"forward" lookup results were returned and were in agreement.
+
+fail:  The DNS evaluation failed.  In particular, the "reverse" and
+"forward" lookups each produced results but they were not in
+agreement, or the "forward" query completed but produced no
+result, e.g., a DNS RCODE of 3, commonly known as NXDOMAIN, or an
+RCODE of 0 (NOERROR) in a reply containing no answers, was
+returned.
+
+temperror:  The DNS evaluation could not be completed due to some
+error that is likely transient in nature, such as a temporary DNS
+error, e.g., a DNS RCODE of 2, commonly known as SERVFAIL, or
+other error condition resulted.  A later attempt may produce a
+final result.
+
+permerror:  The DNS evaluation could not be completed because no PTR
+data are published for the connecting IP address, e.g., a DNS
+RCODE of 3, commonly known as NXDOMAIN, or an RCODE of 0 (NOERROR)
+in a reply containing no answers, was returned.  This prevented
+completion of the evaluation.
+
+=cut
 
 =head1 AUTHOR
 
@@ -136,9 +168,8 @@ sub connect_handler {
 
 sub data_post_handler {
     my ($self, $transaction) = @_;
-
+    my $match = $self->connection->notes('fcrdns_match') || 'error';
-    my $match = $self->connection->notes('fcrdns_match') || 0;
+    $self->store_auth_results("iprev=$match");
-    $transaction->header->add('X-Fcrdns', $match ? 'Yes' : 'No', 0);
     return (DECLINED);
 }
 
@@ -182,13 +213,25 @@ sub has_reverse_dns {
     my $res = $self->init_resolver();
     my $ip  = $self->qp->connection->remote_ip;
 
-    my $query = $res->query($ip) or do {
+    my $query = $res->query($ip, 'PTR') or do {
         if ($res->errorstring eq 'NXDOMAIN') {
             $self->adjust_karma(-1);
+            $self->connection->notes('fcrdns_match', 'permerror');
             $self->log(LOGINFO, "fail, no rDNS: " . $res->errorstring);
             return;
         }
-        $self->log(LOGINFO, "fail, error getting rDNS: " . $res->errorstring);
+        if ( $res->errorstring eq 'SERVFAIL' ) {
+            $self->log(LOGINFO, "fail, error getting rDNS: " . $res->errorstring);
+            $self->connection->notes('fcrdns_match', 'temperror');
+        }
+        elsif ( $res->errorstring eq 'NOERROR' ) {
+            $self->log(LOGINFO, "fail, no PTR (NOERROR)" );
+            $self->connection->notes('fcrdns_match', 'permerror');
+        }
+        else {
+            $self->connection->notes('fcrdns_match', 'fail');
+            $self->log(LOGINFO, "fail, error getting rDNS: " . $res->errorstring);
+        };
         return;
     };
 
@@ -203,6 +246,7 @@ sub has_reverse_dns {
     if (!$hits) {
         $self->adjust_karma(-1);
         $self->log(LOGINFO, "fail, no PTR records");
+        $self->connection->notes('fcrdns_match', 'permerror');
         return;
     }
 
@@ -218,11 +262,13 @@ sub has_forward_dns {
     foreach my $host (keys %{$self->{_args}{ptr_hosts}}) {
 
         $host .= '.' if '.' ne substr($host, -1, 1);    # fully qualify name
-        my $query = $res->search($host) or do {
+        my $query = $res->query($host) or do {
             if ($res->errorstring eq 'NXDOMAIN') {
+                $self->connection->notes('fcrdns_match', 'permerror');
                 $self->log(LOGDEBUG, "host $host does not exist");
                 next;
             }
+            $self->connection->notes('fcrdns_match', 'fail');
             $self->log(LOGDEBUG, "query for $host failed (",
                        $res->errorstring, ")");
             next;
@@ -235,11 +281,13 @@ sub has_forward_dns {
             $self->check_ip_match($rr->address) and return 1;
         }
         if ($hits) {
+            $self->connection->notes('fcrdns_match', 'fail');
             $self->log(LOGDEBUG, "PTR host has forward DNS") if $hits;
             return 1;
         }
     }
     $self->adjust_karma(-1);
+    $self->connection->notes('fcrdns_match', 'fail');
     $self->log(LOGINFO, "fail, no PTR hosts have forward DNS");
     return;
 }
@@ -250,7 +298,7 @@ sub check_ip_match {
 
     if ($ip eq $self->qp->connection->remote_ip) {
         $self->log(LOGDEBUG, "forward ip match");
-        $self->connection->notes('fcrdns_match', 1);
+        $self->connection->notes('fcrdns_match', 'pass');
         $self->adjust_karma(1);
         return 1;
     }
@@ -262,7 +310,7 @@ sub check_ip_match {
 
     if ($dns_net eq $rem_net) {
         $self->log(LOGNOTICE, "forward network match");
-        $self->connection->notes('fcrdns_match', 1);
+        $self->connection->notes('fcrdns_match', 'pass');
         return 1;
     }
     return;

plugins/sender_permitted_from

@@ -133,10 +133,12 @@ sub mail_handler {
         return (DECLINED, "SPF - no response");
     }
 
+    $self->store_auth_results("spf=$code smtp.mailfrom=".$sender->host);
+
     if ($code eq 'pass') {
         $self->adjust_karma(1);
         $transaction->notes('spf_pass_host', lc $sender->host);
-        $self->log(LOGINFO, "pass, $code: $why");
+        $self->log(LOGINFO, "pass, $why");
         return (DECLINED);
     }
 
@@ -235,8 +237,6 @@ sub data_post_handler {
 
     $transaction->header->add('Received-SPF', $result->received_spf_header, 0);
 
-    # consider also adding SPF status to Authentication-Results header
-
     return DECLINED;
 }