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dnsbl, POD tweaks, DENY type tests
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consolidated POD at top of file
added example options to reject_type POD head
added an example loglevel entry

consolidated DENY[SOFT|DISCONNECT] logic into get_reject_type
added tests for get_reject_type
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@msimerson
msimerson committed May 21, 2012
1 parent ed8ce15 commit 9d0c2f8
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231 changes: 117 additions & 114 deletions plugins/dnsbl
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Expand Up @@ -9,6 +9,115 @@ dnsbl - handle DNS BlackList lookups
Plugin that checks the IP address of the incoming connection against Plugin that checks the IP address of the incoming connection against
a configurable set of RBL services. a configurable set of RBL services.
=head1 USAGE
Add the following line to the config/plugins file:
dnsbl [ reject_type disconnect ] [loglevel -1]
=head2 reject_type [ temp | perm ]
To immediately drop the connection (since some blacklisted servers attempt
multiple sends per session), set I<reject_type disconnect>. In most cases,
an IP address that is listed should not be given the opportunity to begin a
new transaction, since even the most volatile blacklists will return the same
answer for a short period of time (the minimum DNS cache period).
Default: perm
=head2 loglevel
Adjust the quantity of logging for this plugin. See docs/logging.pod
dnsbl [loglevel -1]
=head1 CONFIG FILES
This plugin uses the following configuration files. All are optional. Not
specifying dnsbl_zones is like not using the plugin at all.
=head2 dnsbl_zones
Normal ip based dns blocking lists ("RBLs") which contain TXT records are
specified simply as:
relays.ordb.org
spamsources.fabel.dk
To configure RBL services which do not contain TXT records in the DNS,
but only A records (e.g. the RBL+ at http://www.mail-abuse.org), specify your
own error message to return in the SMTP conversation after a colon e.g.
rbl-plus.mail-abuse.org:You are listed at - http://http://www.mail-abuse.org/cgi-bin/lookup?%IP%
The string %IP% will be replaced with the IP address of incoming connection.
Thus a fully specified file could be:
sbl-xbl.spamhaus.org
list.dsbl.org
rbl-plus.mail-abuse.ja.net:Listed by rbl-plus.mail-abuse.ja.net - see <URL:http://www.mail-abuse.org/cgi-bin/lookup?%IP%>
relays.ordb.org
=head2 dnsbl_allow
List of allowed ip addresses that bypass RBL checking. Format is one entry per line,
with either a full IP address or a truncated IP address with a period at the end.
For example:
192.168.1.1
172.16.33.
NB the environment variable RBLSMTPD is considered before this file is
referenced. See below.
=head2 dnsbl_rejectmsg
A textual message that is sent to the sender on an RBL failure. The TXT record
from the RBL list is also sent, but this file can be used to indicate what
action the sender should take.
For example:
If you think you have been blocked in error, then please forward
this entire error message to your ISP so that they can fix their problems.
The next line often contains a URL that can be visited for more information.
=head1 Environment Variables
=head2 RBLSMTPD
The environment variable RBLSMTPD is supported and mimics the behaviour of
Dan Bernstein's rblsmtpd. The exception to this is the '-' char at the
start of RBLSMTPD which is used to force a hard error in Dan's rblsmtpd.
NB I don't really see the benefit
of using a soft error for a site in an RBL list. This just complicates
things as it takes 7 days (or whatever default period) before a user
gets an error email back. In the meantime they are complaining that their
emails are being "lost" :(
=over 4
=item RBLSMTPD is set and non-empty
The contents are used as the SMTP conversation error.
Use this for forcibly blocking sites you don't like
=item RBLSMTPD is set, but empty
In this case no RBL checks are made.
This can be used for local addresses.
=item RBLSMTPD is not set
All RBL checks will be made.
This is the setting for remote sites that you want to check against RBL.
=back
=head1 Revisions
See: https://github.com/smtpd/qpsmtpd/commits/master/plugins/dnsbl
=cut =cut


sub register { sub register {
Expand All @@ -20,9 +129,6 @@ sub register {
else { else {
$self->{_args} = { @_ }; $self->{_args} = { @_ };
}; };

my $rej = $self->{_args}{reject_type};
$self->{_dnsbl}{DENY} = (defined $rej && $rej =~ /^disconnect$/i) ? DENY_DISCONNECT : DENY;
} }


sub hook_connect { sub hook_connect {
Expand Down Expand Up @@ -207,7 +313,7 @@ sub hook_rcpt {
$result =~ s/%IP%/$remote_ip/g; $result =~ s/%IP%/$remote_ip/g;
my $msg = $self->qp->config('dnsbl_rejectmsg'); my $msg = $self->qp->config('dnsbl_rejectmsg');
$self->log(LOGINFO, "fail: $msg"); $self->log(LOGINFO, "fail: $msg");
return ($self->{_dnsbl}->{DENY}, join(' ', $msg, $result)); return ( $self->get_reject_type(), join(' ', $msg, $result));
} }


my $note = $self->process_sockets or return DECLINED; my $note = $self->process_sockets or return DECLINED;
Expand All @@ -222,7 +328,7 @@ sub hook_rcpt {
} }


$self->log(LOGINFO, 'fail'); $self->log(LOGINFO, 'fail');
return ($self->{_dnsbl}->{DENY}, $note); return ( $self->get_reject_type(), $note);
} }


sub hook_disconnect { sub hook_disconnect {
Expand All @@ -233,114 +339,11 @@ sub hook_disconnect {
return DECLINED; return DECLINED;
} }


=head1 USAGE sub get_reject_type {
my $self = shift;
Add the following line to the config/plugins file:
dnsbl [ reject_type disconnect ] [loglevel -1]
=head2 reject_type
To immediately drop the connection (since some blacklisted servers attempt
multiple sends per session), set the optional argument I<reject_type> to
"disconnect" on the config/plugin entry. In most cases, an
IP address that is listed should not be given the opportunity to begin
a new transaction, since even the most volatile blacklists will return
the same answer for a short period of time (the minimum DNS cache period).
=head2 loglevel
Adjust the quantity of logging for this plugin. See docs/logging.pod
=head1 CONFIG FILES
=over 4
This plugin uses the following configuration files. All are optional. Not
specifying dnsbl_zones is like not using the plugin at all.
=item dnsbl_zones
Normal ip based dns blocking lists ("RBLs") which contain TXT records are
specified simply as:
relays.ordb.org
spamsources.fabel.dk
To configure RBL services which do not contain TXT records in the DNS,
but only A records (e.g. the RBL+ at http://www.mail-abuse.org), specify your
own error message to return in the SMTP conversation after a colon e.g.
rbl-plus.mail-abuse.org:You are listed at - http://http://www.mail-abuse.org/cgi-bin/lookup?%IP%
The string %IP% will be replaced with the IP address of incoming connection.
Thus a fully specified file could be:
sbl-xbl.spamhaus.org
list.dsbl.org
rbl-plus.mail-abuse.ja.net:Listed by rbl-plus.mail-abuse.ja.net - see <URL:http://www.mail-abuse.org/cgi-bin/lookup?%IP%>
relays.ordb.org
=item dnsbl_allow
List of allowed ip addresses that bypass RBL checking. Format is one entry per line,
with either a full IP address or a truncated IP address with a period at the end.
For example:
192.168.1.1
172.16.33.
NB the environment variable RBLSMTPD is considered before this file is
referenced. See below.
=item dnsbl_rejectmsg
A textual message that is sent to the sender on an RBL failure. The TXT record
from the RBL list is also sent, but this file can be used to indicate what
action the sender should take.
For example:
If you think you have been blocked in error, then please forward
this entire error message to your ISP so that they can fix their problems.
The next line often contains a URL that can be visited for more information.
=back
=head1 Environment Variables
=head2 RBLSMTPD
The environment variable RBLSMTPD is supported and mimics the behaviour of
Dan Bernstein's rblsmtpd. The exception to this is the '-' char at the
start of RBLSMTPD which is used to force a hard error in Dan's rblsmtpd.
NB I don't really see the benefit
of using a soft error for a site in an RBL list. This just complicates
things as it takes 7 days (or whatever default period) before a user
gets an error email back. In the meantime they are complaining that their
emails are being "lost" :(
=over 4
=item RBLSMTPD is set and non-empty
The contents are used as the SMTP conversation error.
Use this for forcibly blocking sites you don't like
=item RBLSMTPD is set, but empty
In this case no RBL checks are made.
This can be used for local addresses.
=item RBLSMTPD is not set
All RBL checks will be made.
This is the setting for remote sites that you want to check against RBL.
=back
=head1 Revisions


See: http://cvs.perl.org/viewcvs/qpsmtpd/plugins/dnsbl return $self->{_args}{reject_type} eq 'temp' ? DENYSOFT
: $self->{_args}{reject_type} eq 'disconnect' ? DENY_DISCONNECT
: DENY;
};


=cut
34 changes: 24 additions & 10 deletions t/plugin_tests/dnsbl
View file
Expand Up @@ -13,6 +13,7 @@ sub register_tests {
$self->register_test('test_ip_whitelisted', 3); $self->register_test('test_ip_whitelisted', 3);
$self->register_test('test_is_set_rblsmtpd', 4); $self->register_test('test_is_set_rblsmtpd', 4);
$self->register_test('test_hook_disconnect', 1); $self->register_test('test_hook_disconnect', 1);
$self->register_test('test_reject_type', 3);
} }


sub test_ip_whitelisted { sub test_ip_whitelisted {
Expand All @@ -21,43 +22,44 @@ sub test_ip_whitelisted {
$self->qp->connection->remote_ip('10.1.1.1'); $self->qp->connection->remote_ip('10.1.1.1');


$self->qp->connection->relay_client(1); $self->qp->connection->relay_client(1);
ok( $self->ip_whitelisted('10.1.1.1'), "ip_whitelisted, +"); ok( $self->ip_whitelisted('10.1.1.1'), "yes, +");


$self->qp->connection->relay_client(0); $self->qp->connection->relay_client(0);
ok( ! $self->ip_whitelisted('10.1.1.1'), "ip_whitelisted, -"); ok( ! $self->ip_whitelisted('10.1.1.1'), "no, -");


$self->qp->connection->notes('whitelisthost', 'hello honey!'); $self->qp->connection->notes('whitelisthost', 'hello honey!');
ok( $self->ip_whitelisted('10.1.1.1'), "ip_whitelisted, +"); ok( $self->ip_whitelisted('10.1.1.1'), "yes, +");
$self->qp->connection->notes('whitelisthost', undef); $self->qp->connection->notes('whitelisthost', undef);
}; };


sub test_is_set_rblsmtpd { sub test_is_set_rblsmtpd {
my $self = shift; my $self = shift;


$self->qp->connection->remote_ip('10.1.1.1'); $self->qp->connection->remote_ip('10.1.1.1');
ok( ! defined $self->is_set_rblsmtpd('10.1.1.1'), "is_set_rblsmtpd, undef"); ok( ! defined $self->is_set_rblsmtpd('10.1.1.1'), "undef");


$ENV{RBLSMTPD} = "Yes we can!"; $ENV{RBLSMTPD} = "Yes we can!";
cmp_ok( 'Yes we can!','eq',$self->is_set_rblsmtpd('10.1.1.1'), "is_set_rblsmtpd, value"); cmp_ok( 'Yes we can!','eq',$self->is_set_rblsmtpd('10.1.1.1'), "value");


$ENV{RBLSMTPD} = "Oh yeah?"; $ENV{RBLSMTPD} = "Oh yeah?";
cmp_ok( 'Oh yeah?','eq',$self->is_set_rblsmtpd('10.1.1.1'), "is_set_rblsmtpd, value"); cmp_ok( 'Oh yeah?','eq',$self->is_set_rblsmtpd('10.1.1.1'), "value");


$ENV{RBLSMTPD} = ''; $ENV{RBLSMTPD} = '';
cmp_ok( 1,'==',$self->is_set_rblsmtpd('10.1.1.1'), "is_set_rblsmtpd, empty"); cmp_ok( 1,'==',$self->is_set_rblsmtpd('10.1.1.1'), "empty");
}; };


sub test_hook_connect { sub test_hook_connect {
my $self = shift; my $self = shift;


my $connection = $self->qp->connection; my $connection = $self->qp->connection;
$connection->relay_client(0); # other tests may leave it enabled
$connection->remote_ip('127.0.0.2'); # standard dnsbl test value $connection->remote_ip('127.0.0.2'); # standard dnsbl test value


cmp_ok( DECLINED, '==', $self->hook_connect($self->qp->transaction), cmp_ok( DECLINED, '==', $self->hook_connect($self->qp->transaction),
"hook_connect +"); "connect +");


ok($connection->notes('dnsbl_sockets'), "hook_connect, sockets"); ok($connection->notes('dnsbl_sockets'), "sockets +");
ok($connection->notes('dnsbl_domains'), "hook_connect, domains"); ok($connection->notes('dnsbl_domains'), "domains +");
} }


sub test_hook_rcpt { sub test_hook_rcpt {
Expand All @@ -75,3 +77,15 @@ sub test_hook_disconnect {
"hook_disconnect +"); "hook_disconnect +");
} }


sub test_reject_type {
my $self = shift;

$self->{_args}{reject_type} = undef;
cmp_ok( $self->get_reject_type(), '==', DENY, "default");

$self->{_args}{reject_type} = 'temp';
cmp_ok( $self->get_reject_type(), '==', DENYSOFT, "defer");

$self->{_args}{reject_type} = 'disconnect';
cmp_ok( $self->get_reject_type(), '==', DENY_DISCONNECT, "disconnect");
};

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