dkim: signer: header: rework early exits on multiple from addresses

Signed-off-by: Stoiko Ivanov <s.ivanov@proxmox.com>

diff --git a/src/PMG/DKIMSign.pm b/src/PMG/DKIMSign.pm
index 3e4c5156718e248abfb0e763da0c2122df2a02ef..6f309c874f58f22b5ae7c4b635f9366b701db130 100644 (file)
--- a/src/PMG/DKIMSign.pm
+++ b/src/PMG/DKIMSign.pm
@@ -97,18 +97,17 @@ sub parse_headers_for_signing {
     # [1] https://datatracker.ietf.org/doc/html/rfc7489#section-6.6.1
     my ($entity) = @_;
 
-    my $from_count = 0;
     my $domain;
 
     my @from_headers = $entity->head->get('from');
     foreach my $from_header (@from_headers) {
        my @addresses = Email::Address::XS::parse_email_addresses($from_header);
-       $from_count += scalar(@addresses);
-       $domain = $addresses[0]->host() if scalar(@addresses) > 0;
+       die "there is more than one sender in the header\n"
+           if defined($domain) || scalar(@addresses) > 1;
+       $domain = $addresses[0]->host();
     }
 
-    die "there is more than one sender in the header\n" if $from_count > 1;
-    die "there is no sender in the header\n" if $from_count == 0;
+    die "there is no sender in the header\n" if !defined($domain);
     return $domain;
 }