skip rewriting when it's not useful

2 files changed, 32 insertions, 27 deletions

diff --git a/lib/Sietima/Role/NoSpoof.pm b/lib/Sietima/Role/NoSpoof.pm
index ba703cb..5c419df 100644
--- a/lib/Sietima/Role/NoSpoof.pm
+++ b/lib/Sietima/Role/NoSpoof.pm
@@ -14,10 +14,10 @@ use namespace::clean;
 =head1 DESCRIPTION
 
 A L<< C<Sietima> >> list with this role applied will replace the
-`From` address with its own L<<
+C<From> address with its own L<<
 C<post_address>|Sietima::Role::WithPostAddress >> (this is a
 "sub-role" of L<< C<WithPostAddress>|Sietima::Role::WithPostAddress
->>).
+>>) I<if> the C<From> is on a different domain.
 
 This will make the list DMARC-compliant.
 
@@ -29,11 +29,13 @@ around munge_mail => sub ($orig,$self,$incoming_mail) {
     my $sender = $self->post_address->address;
     my ($from) = Email::Address->parse($incoming_mail->header_str('From'));
 
-    $from->address($sender);
+    if ($from->host ne $self->post_address->host) {
+        $from->address($sender);
 
-    $incoming_mail->header_str_set(
-        From => $from,
-    );
+        $incoming_mail->header_str_set(
+            From => $from,
+        );
+    }
 
     return $self->$orig($incoming_mail);
 };
diff --git a/lib/Sietima/Role/NoSpoof/DMARC.pm b/lib/Sietima/Role/NoSpoof/DMARC.pm
index de021da..4a6cedf 100644
--- a/lib/Sietima/Role/NoSpoof/DMARC.pm
+++ b/lib/Sietima/Role/NoSpoof/DMARC.pm
@@ -18,7 +18,8 @@ A L<< C<Sietima> >> list with this role applied will replace the
 C<From> address with its own L<<
 C<post_address>|Sietima::Role::WithPostAddress >> (this is a
 "sub-role" of L<< C<WithPostAddress>|Sietima::Role::WithPostAddress
->>) I<if> the originating address's DMARC policy requires it.
+>>) I<if> the C<From> is on a different domain and the originating
+address's DMARC policy requires it.
 
 This will make the list DMARC-compliant while minimising the changes
 to the messages.
@@ -55,36 +56,38 @@ around munge_mail => sub ($orig,$self,$incoming_mail) {
     my ($from) = Email::Address->parse($incoming_mail->header_str('From'));
     my $from_domain = $from->host;
 
-    my $dmarc = Mail::DMARC::PurePerl->new(
-        resolver => $self->dmarc_resolver,
-    );
-    $dmarc->header_from($from_domain);
+    if ($from_domain ne $self->post_address->host) {
+        my $dmarc = Mail::DMARC::PurePerl->new(
+            resolver => $self->dmarc_resolver,
+        );
+        $dmarc->header_from($from_domain);
 
-    if (my $policy = $dmarc->discover_policy) {
-        # sp applies to sub-domains, defaults to p; p applies to the
-        # domain itself, and is required
-        my $relevant_value = $dmarc->is_subdomain
-            ? ( $policy->sp // $policy->p )
-            : $policy->p;
+        if (my $policy = $dmarc->discover_policy) {
+            # sp applies to sub-domains, defaults to p; p applies to
+            # the domain itself, and is required
+            my $relevant_value = $dmarc->is_subdomain
+                ? ( $policy->sp // $policy->p )
+                : $policy->p;
 
-        if ($relevant_value ne 'none') {
-            $incoming_mail->header_str_set(
-                'Original-From' => $from,
-            );
+            if ($relevant_value ne 'none') {
+                $incoming_mail->header_str_set(
+                    'Original-From' => $from,
+                );
 
-            $from->address($sender);
+                $from->address($sender);
 
-            $incoming_mail->header_str_set(
-                From => $from,
-            );
+                $incoming_mail->header_str_set(
+                    From => $from,
+                );
 
-            return $self->$orig($incoming_mail);
+                return $self->$orig($incoming_mail);
+            }
         }
     }
 
     $incoming_mail->header_str_set(
         Sender => $sender,
-    );
+    ) if $sender ne $from->address;
 
     return $self->$orig($incoming_mail);