43 lines
1.1 KiB
Plaintext
43 lines
1.1 KiB
Plaintext
=head1 NAME
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check_earlytalker - Check that the client doesn't talk before we send the SMTP banner
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=head1 DESCRIPTION
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Hooks connect, checks to see if the remote host starts talking before
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we've issued a 2xx greeting. If so, we're likely looking at a
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direct-to-MX spam agent which pipelines its entire SMTP conversation,
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and will happily dump an entire spam into our mail log even if later
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tests deny acceptance.
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Such clients gets a 450 error code.
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=head1 TODO
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Make how long we wait before reading from the socket configurable
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(currently 1 second)
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Make the soft/hard response code configurable (currently DENYSOFT)
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=cut
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use IO::Select;
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sub register {
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my ($self, $qp) = @_;
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$self->register_hook('connect', 'connect_handler');
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}
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sub connect_handler {
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my ($self, $transaction) = @_;
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my $in = new IO::Select;
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$in->add(\*STDIN) || return DECLINED;
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if ($in->can_read(1)) {
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$self->log(LOGDEBUG, "remote host started talking before we said hello");
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return (DENYSOFT, "Don't be rude and talk before I say hello!");
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}
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$self->log(LOGINFO,"remote host said nothing spontaneous, proceeding");
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return DECLINED;
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}
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