150 lines
3.8 KiB
Perl
150 lines
3.8 KiB
Perl
#!perl -w
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use Qpsmtpd::DSN;
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use Net::DNS qw(mx);
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use Socket;
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use Net::IP qw(:PROC);
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use Qpsmtpd::TcpServer;
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my %invalid = ();
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my $has_ipv6 = Qpsmtpd::TcpServer::has_ipv6();
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sub hook_mail {
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my ($self, $transaction, $sender, %param) = @_;
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return DECLINED if $self->connection->notes('whitelisthost');
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foreach my $i ($self->qp->config("invalid_resolvable_fromhost")) {
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$i =~ s/^\s*//;
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$i =~ s/\s*$//;
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if ($i =~ m#^((\d{1,3}\.){3}\d{1,3})/(\d\d?)#) {
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$invalid{$1} = $3;
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}
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}
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if ($sender ne "<>"
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and $self->qp->config("require_resolvable_fromhost")
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and !$self->check_dns($sender->host)) {
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if ($sender->host) {
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$transaction->notes('temp_resolver_failed', $sender->host);
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}
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else {
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# default of addr_bad_from_system is DENY, we use DENYSOFT here to
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# get the same behaviour as without Qpsmtpd::DSN...
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return Qpsmtpd::DSN->addr_bad_from_system(DENYSOFT,
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"FQDN required in the envelope sender");
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}
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}
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return DECLINED;
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}
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sub hook_rcpt {
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my ($self, $transaction, $recipient, %args) = @_;
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if (my $host = $transaction->notes('temp_resolver_failed')) {
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# default of temp_resolver_failed is DENYSOFT
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return Qpsmtpd::DSN->temp_resolver_failed("Could not resolve " . $host);
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}
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return DECLINED;
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}
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sub check_dns {
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my ($self, $host) = @_;
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my @host_answers;
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# for stuff where we can't even parse a hostname out of the address
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return 0 unless $host;
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return 1 if $host =~ m/^\[(\d{1,3}\.){3}\d{1,3}\]$/;
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my $res = new Net::DNS::Resolver(dnsrch => 0);
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$res->tcp_timeout(30);
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$res->udp_timeout(30);
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my @mx = mx($res, $host);
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foreach my $mx (@mx) {
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# if any MX is valid, then we consider the domain
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# resolvable
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return 1 if mx_valid($self, $mx->exchange, $host);
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}
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# if there are MX records, and we got here,
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# then none of them are valid
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return 0 if (@mx > 0);
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my $query = $res->search($host);
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if ($query) {
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foreach my $rrA ($query->answer) {
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push(@host_answers, $rrA);
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}
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}
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if ($has_ipv6) {
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my $query = $res->search($host, 'AAAA');
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if ($query) {
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foreach my $rrAAAA ($query->answer) {
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push(@host_answers, $rrAAAA);
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}
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}
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}
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if (@host_answers) {
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foreach my $rr (@host_answers) {
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return is_valid($rr->address) if $rr->type eq "A" or $rr->type eq "AAAA";
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return mx_valid($self, $rr->exchange, $host) if $rr->type eq "MX";
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}
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}
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else {
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$self->log(LOGWARN, "$$ query for $host failed: ", $res->errorstring)
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unless $res->errorstring eq "NXDOMAIN";
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}
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return 0;
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}
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sub is_valid {
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my $ip = shift;
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my ($net,$mask);
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### while (($net,$mask) = each %invalid) {
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### ... does NOT reset to beginning, will start on
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### 2nd invocation after where it denied the first time..., so
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### 2nd time the same "MAIL FROM" would be accepted!
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foreach $net (keys %invalid) {
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$mask = $invalid{$net};
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$mask = pack "B32", "1"x($mask)."0"x(32-$mask);
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return 0
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if join(".", unpack("C4", inet_aton($ip) & $mask)) eq $net;
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}
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return 1;
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}
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sub mx_valid {
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my ($self, $name, $host) = @_;
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my $res = new Net::DNS::Resolver(dnsrch => 0);
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# IP in MX
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return is_valid($name) if ip_is_ipv4($name) or ip_is_ipv6($name);
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my @mx_answers;
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my $query = $res->search($name, 'A');
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if ($query) {
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foreach my $rrA ($query->answer) {
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push(@mx_answers, $rrA);
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}
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}
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if ($has_ipv6) {
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my $query = $res->search($name, 'AAAA');
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if ($query) {
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foreach my $rrAAAA ($query->answer) {
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push(@mx_answers, $rrAAAA);
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}
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}
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}
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if (@mx_answers) {
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foreach my $rr (@mx_answers) {
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next unless $rr->type eq "A" or $rr->type eq "AAAA";
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return is_valid($rr->address);
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}
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}
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else {
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$self->log(LOGWARN, "$$ query for $host failed: ", $res->errorstring)
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unless $res->errorstring eq "NXDOMAIN";
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}
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return 0;
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}
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