c3dff626cb
make sure return path is empty, per RFC 3834
97 lines
2.2 KiB
Perl
97 lines
2.2 KiB
Perl
#!perl -w
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=head1 NAME
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bogus_bounce - Check that a bounce message isn't bogus
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=head1 DESCRIPTION
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This plugin is designed to reject bogus bounce messages.
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In our case a bogus bounce message is defined as a bounce message
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which has more than a single recipient.
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=head1 CONFIGURATION
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Only a single argument is recognized and is assumed to be the default
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action. Valid settings are:
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=over 8
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=item log
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Merely log the receipt of the bogus bounce (the default behaviour).
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=item deny
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Deny with a hard error code.
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=item denysoft
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Deny with a soft error code.
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=back
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=head1 AUTHOR
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2010 - Steve Kemp - http://steve.org.uk/Software/qpsmtpd/
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2013 - Matt Simerson - added Return Path check
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=cut
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sub register {
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my ($self, $qp) = (shift, shift);
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if ( @_ % 2 ) {
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$self->{_args}{action} = shift;
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}
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else {
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$self->{_args} = { @_ };
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};
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if ( ! defined $self->{_args}{reject} ) {
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$self->{_args}{reject} = 0; # legacy default
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};
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# we only need to check for deferral, default is DENY
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if ( $self->{_args}{action} =~ /soft/i ) {
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$self->{_args}{reject_type} = 'temp';
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}
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}
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sub hook_data_post {
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my ($self, $transaction) = (@_);
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#
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# Find the sender, quit processing if this isn't a bounce.
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#
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my $sender = $transaction->sender->address || undef;
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if ( $sender && $sender ne '<>') {
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$self->log(LOGINFO, "pass, not a null sender");
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return DECLINED;
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};
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# at this point we know it is a bounce, via the null-envelope.
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#
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# Count the recipients. Valid bounces have a single recipient
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#
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my @to = $transaction->recipients || ();
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if (scalar @to != 1) {
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$self->log(LOGINFO, "fail, bogus bounce to: " . join(',', @to));
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return $self->get_reject( "fail, this bounce message does not have 1 recipient" );
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};
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# validate that Return-Path is empty, RFC 3834
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my $rp = $transaction->header->get('Return-Path');
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if ( $rp && $rp ne '<>' ) {
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$self->log(LOGINFO, "fail, bounce messages must not have a Return-Path");
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return $self->get_reject( "a bounce return path must be empty (RFC 3834)" );
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};
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$self->log(LOGINFO, "pass, single recipient, empty Return-Path");
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return DECLINED;
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}
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