1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
|
#!/usr/bin/perl -w
use Qpsmtpd::DSN;
use ParaDNS;
use Socket;
use Qpsmtpd::TcpServer;
my %invalid = ();
my $has_ipv6 = Qpsmtpd::TcpServer::has_ipv6();
sub register {
my ( $self, $qp ) = @_;
foreach my $i ( $self->qp->config("invalid_resolvable_fromhost") ) {
$i =~ s/^\s*//;
$i =~ s/\s*$//;
if ( $i =~ m#^((\d{1,3}\.){3}\d{1,3})/(\d\d?)# ) {
$invalid{$1} = $3;
}
}
$self->register_hook( mail => 'hook_mail_start' );
$self->register_hook( mail => 'hook_mail_done' );
}
sub hook_mail_start {
my ( $self, $transaction, $sender ) = @_;
return DECLINED
if ( $self->qp->connection->notes('whitelisthost') );
if ( $sender ne "<>" ) {
unless ( $sender->host ) {
# default of addr_bad_from_system is DENY, we use DENYSOFT here to
# get the same behaviour as without Qpsmtpd::DSN...
return Qpsmtpd::DSN->addr_bad_from_system( DENYSOFT,
"FQDN required in the envelope sender" );
}
return DECLINED if $sender->host =~ m/^\[(\d{1,3}\.){3}\d{1,3}\]$/;
unless ($self->check_dns( $sender->host )) {
return Qpsmtpd::DSN->temp_resolver_failed(
"Could not resolve " . $sender->host );
}
return YIELD;
}
return DECLINED;
}
sub hook_mail_done {
my ( $self, $transaction, $sender ) = @_;
return DECLINED
if ( $self->qp->connection->notes('whitelisthost') );
if ( $sender ne "<>" && !$transaction->notes('resolvable_fromhost') ) {
# default of temp_resolver_failed is DENYSOFT
return Qpsmtpd::DSN->temp_resolver_failed(
"Could not resolve " . $sender->host );
}
return DECLINED;
}
sub check_dns {
my ( $self, $host ) = @_;
my @host_answers;
my $qp = $self->qp;
$qp->input_sock->pause_read;
my $a_records = [];
my $num_queries = 1; # queries in progress
my $mx_found = 0;
ParaDNS->new(
callback => sub {
my $mx = shift;
return if $mx =~ /^[A-Z]+$/; # error
my $addr = $mx->[0];
$mx_found = 1;
$num_queries++;
ParaDNS->new(
callback => sub { push @$a_records, $_[0] if $_[0] !~ /^[A-Z]+$/; },
finished => sub { $num_queries--; $self->finish_up($qp, $a_records, $num_queries) },
host => $addr,
type => 'A',
);
if ($has_ipv6) {
$num_queries++;
ParaDNS->new(
callback => sub { push @$a_records, $_[0] if $_[0] !~ /^[A-Z]+$/; },
finished => sub { $num_queries--; $self->finish_up($qp, $a_records, $num_queries) },
host => $addr,
type => 'AAAA',
);
}
},
finished => sub {
unless ($mx_found) {
$num_queries++;
ParaDNS->new(
callback => sub { push @$a_records, $_[0] if $_[0] !~ /^[A-Z]+$/; },
finished => sub { $num_queries--; $self->finish_up($qp, $a_records, $num_queries) },
host => $host,
type => 'A',
);
if ($has_ipv6) {
$num_queries++;
ParaDNS->new(
callback => sub { push @$a_records, $_[0] if $_[0] !~ /^[A-Z]+$/; },
finished => sub { $num_queries--; $self->finish_up($qp, $a_records, $num_queries) },
host => $host,
type => 'AAAA',
);
}
}
$num_queries--;
$self->finish_up($qp, $a_records, $num_queries);
},
host => $host,
type => 'MX',
) or $qp->input_sock->continue_read, return;
return 1;
}
sub finish_up {
my ($self, $qp, $a_records, $num_queries) = @_;
return if defined $qp->transaction->notes('resolvable_fromhost');
foreach my $addr (@$a_records) {
if (is_valid($addr)) {
$qp->transaction->notes('resolvable_fromhost', 1);
$qp->input_sock->continue_read;
$qp->run_continuation;
return;
}
}
unless ($num_queries) {
# all queries returned no valid response
$qp->transaction->notes('resolvable_fromhost', 0);
$qp->input_sock->continue_read;
$qp->run_continuation;
}
}
sub is_valid {
my $ip = shift;
my ( $net, $mask );
foreach $net ( keys %invalid ) {
$mask = $invalid{$net};
$mask = pack "B32", "1" x ($mask) . "0" x ( 32 - $mask );
return 0
if join( ".", unpack( "C4", inet_aton($ip) & $mask ) ) eq $net;
}
return 1;
}
# vim: ts=4 sw=4 expandtab syn=perl
|
