c840a1d04f
o plugins/check_badmailfromto - New plugin in the style of check_badmailfrom, which matches a pair of FROM/TO and makes it seem like the recipient's address no longer exists (but only from the matching sender's point of view). Useful for stalkers and other harassment cases. o plugins/dns_whitelist_soft - New plugin to provide a DNS-based whitelist (good for distributed sites). o various files - Replaced tab character with 8 spaces and adjusted line breaks for better readability. Changes by mct@toren.net (Michael C. Toren) o lib/Qpsmtpd/SMTP.pm - Assumes a MAIL FROM value of "<#@[]>" (utilized by qmail to indicate a null sender when generating a doublebounce message) is equivalent to "<>". Previously qpsmtpd complained that the value could not be parsed. - Adds LOGIN to the default list of supported auth mechanisms. The documentation in Auth.pm indicated that auth-login was not currently supported due to lack of functionality, however I can confirm that LOGIN appears to work fine as tested by using msmtp (http://msmtp.sourceforge.net/). Are there any indications that LOGIN support is actually broken in the current implementation? - Removes the "X-Qpsmtpd-Auth: True" header appended when a message has been sent by an authenticated user. One problem with such a header is that it's impossible to say which SMTP hop added it, and it provides no information which could be used to backtrack the transaction. I grepped through my mail archives a bit looking for how other MTAs handled the problem, and decided it would be best to place this information in the Received: header: Received: from remotehost (HELO remotehost) (192.168.42.42) (smtp-auth username foo, mechanism cram-md5) by mail.netisland.net (qpsmtpd/0.28) with ESMTP; <date> o lib/Qpsmtpd/Auth.pm: - Documentation update for the arguments passed to an auth handler; previously the $mechanism argument was not mentioned, which threw off the argument offsets. - Documentation update for auth-login removing the warning that auth-login is not currently supported due to lack of functionality. - Fix to execute a generic auth hook when a more specific auth-$mechanism hook does not exist. (Previously posted to the list last week.) - Upon authentication, sets $session->{_auth_user} and $session->{_auth_mechanism} so that SMTP.pm can include them in the Received: header. o plugins/queue/qmail-queue - Added a timestamp and the qmail-queue qp identifier to the "Queued!" 250 message, for compatibility with qmail-smtpd, which can be very useful for tracking message delivery from machine to machine. For example, the new 250 message might be: 250 Queued! 1105927468 qp 3210 <1105927457@netisland.net> qmail-smtpd returns: 250 ok 1106546213 qp 7129 Additionally, for consistency angle brackets are placed around the Message-ID displayed in the 250 if they were missing in the message header. o plugins/check_badmailfrom: - Changed the error message from "Mail from $bad not accepted here" to "sorry, your envelope sender is in my badmailfrom list", for compatibility with qmail-smtpd. I didn't see any reason to share with the sender the value of $bad, especially for situations where the sender was rejected resulting from a wildcard. o plugins/check_earlytalker: o plugins/require_resolvable_fromhost: - No longer checks for earlytalkers or resolvable senders if the connection note "whitelistclient" is set, which is nice for helping backup MX hosts empty their queue faster. o plugins/count_unrecognized_commands: - Return code changed from DENY_DISCONNECT, which isn't valid in an unrecognized_command hook, to DENY, which in this context drops the connection anyway. (Previously posted to the list last week.) git-svn-id: https://svn.perl.org/qpsmtpd/trunk@356 958fd67b-6ff1-0310-b445-bb7760255be9
108 lines
3.0 KiB
Plaintext
108 lines
3.0 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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Checks to see if the remote host starts talking before we've issued a 2xx
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greeting. If so, we're likely looking at a direct-to-MX spam agent which
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pipelines its entire SMTP conversation, and will happily dump an entire spam
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into our mail log even if later tests deny acceptance.
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Depending on configuration, clients which behave in this way are either
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immediately disconnected with a deny or denysoft code, or else are issued this
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on all mail/rcpt commands in the transaction.
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=head1 CONFIGURATION
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=over 4
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=item wait [integer]
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The number of seconds to delay the initial greeting to see if the connecting
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host speaks first. The default is 1.
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=item action [string: deny, denysoft, log]
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What to do when matching an early-talker -- the options are I<deny>,
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I<denysoft> or I<log>.
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If I<log> is specified, the connection will be allowed to proceed as normal,
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and only a warning will be logged.
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The default is I<denysoft>.
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=item defer-reject [boolean]
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When an early-talker is detected, if this option is set to a true value, the
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SMTP greeting will be issued as usual, but all RCPT/MAIL commands will be
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issued a deny or denysoft (depending on the value of I<action>). The default
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is to react at the SMTP greeting stage by issuing the apropriate response code
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and terminating the SMTP connection.
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=back
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=cut
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use IO::Select;
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use warnings;
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use strict;
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sub register {
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my ($self, $qp, @args) = @_;
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if (@args % 2) {
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$self->log(LOGERROR, "Unrecognized/mismatched arguments");
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return undef;
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}
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$self->{_args} = {
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'wait' => 1,
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'action' => 'denysoft',
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'defer-reject' => 0,
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@args,
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};
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$self->register_hook('connect', 'connect_handler');
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$self->register_hook('mail', 'mail_handler')
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if $self->{_args}->{'defer-reject'};
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1;
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}
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sub connect_handler {
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my ($self, $transaction) = @_;
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my $in = new IO::Select;
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my $ip = $self->qp->connection->remote_ip;
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return DECLINED
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if ($self->qp->connection->notes('whitelistclient'));
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$in->add(\*STDIN) || return DECLINED;
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if ($in->can_read($self->{_args}->{'wait'})) {
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$self->log(LOGNOTICE, "remote host started talking before we said hello [$ip]");
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if ($self->{_args}->{'defer-reject'}) {
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$self->qp->connection->notes('earlytalker', 1);
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} else {
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my $msg = 'Connecting host started transmitting before SMTP greeting';
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return (DENY,$msg) if $self->{_args}->{'action'} eq 'deny';
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return (DENYSOFT,$msg) if $self->{_args}->{'action'} eq 'denysoft';
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}
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} else {
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$self->log(LOGINFO, 'remote host said nothing spontaneous, proceeding');
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}
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return DECLINED;
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}
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sub mail_handler {
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my ($self, $txn) = @_;
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my $msg = 'Connecting host started transmitting before SMTP greeting';
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return DECLINED unless $self->qp->connection->notes('earlytalker');
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return (DENY,$msg) if $self->{_args}->{'action'} eq 'deny';
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return (DENYSOFT,$msg) if $self->{_args}->{'action'} eq 'denysoft';
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return DECLINED;
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}
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1;
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