rulesystem: limit linelength of disclaimer to 998 bytes

As described in
http://www.postfix.org/postconf.5.html#smtp_line_length_limit

postfix splits lines which are longer by inserting <cr><lf><space> to
adhere with RFC 5322 (section 2.1.1):
https://datatracker.ietf.org/doc/html/rfc5322#section-2.1.1
(or actually section 4.5.3.1.6. where characters are translated to
octets)

If a longer line is part of the disclaimer pmg-smtp-filter adds it
without this modification, which breaks DKIM signatures (since the
body is modified by postfix after the body hash is computed)

regular-expression matching is used instead of length(), because the
limit is on line-length (and a disclaimer can contain multiple lines)

reported in our community forum:
https://forum.proxmox.com/threads/.97919/

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

diff --git a/src/PMG/RuleDB/Disclaimer.pm b/src/PMG/RuleDB/Disclaimer.pm
index 1b1accfcba474bb084e2f9d83d2e0d8df81d4016..d3003b2c9d6caa2be6d1a429d47a73d37d24f4cc 100644 (file)
--- a/src/PMG/RuleDB/Disclaimer.pm
+++ b/src/PMG/RuleDB/Disclaimer.pm
@@ -84,12 +84,17 @@ sub save {
     defined($self->{ogroup}) || die "undefined object attribute: ERROR";
     defined($self->{value}) || die "undefined object attribute: ERROR";
 
+    my $value = encode('UTF-8', $self->{value});
+    if ($value =~ /^.{998,}$/m) {
+       die "too long line in disclaimer - breaks RFC 5322!\n";
+    }
+
     if (defined ($self->{id})) {
        # update
        
        $ruledb->{dbh}->do(
            "UPDATE Object SET Value = ? WHERE ID = ?", 
-           undef, encode('UTF-8', $self->{value}), $self->{id});
+           undef, $value, $self->{id});
 
     } else {
        # insert
@@ -98,7 +103,7 @@ sub save {
            "INSERT INTO Object (Objectgroup_ID, ObjectType, Value) " .
            "VALUES (?, ?, ?);");
 
-       $sth->execute($self->ogroup, $self->otype, encode('UTF-8', $self->{value}));
+       $sth->execute($self->ogroup, $self->otype, $value);
     
        $self->{id} = PMG::Utils::lastid($ruledb->{dbh}, 'object_id_seq'); 
     }