qpsmtpd/qpsmtpd
2001-10-30 10:05:15 +00:00

319 lines
9.3 KiB
Perl
Executable File

#!/home/perl/bin/perl -w
# Copyright (c) 2001 Ask Bjoern Hansen. See the LICENSE file for details.
# The "command dispatch" system is taken from colobus - http://trainedmonkey.com/colobus/
#
# this is designed to be run under tcpserver
# (http://cr.yp.to/ucspi-tcp.html)
# or inetd if you're into that sort of thing
#
#
# For more information see http://develooper.com/code/qpsmtpd/
#
#
package QPsmtpd;
$QPsmtpd::VERSION = "0.04";
use strict;
$| = 1;
use Mail::Address ();
use Sys::Hostname;
use IPC::Open2;
use Data::Dumper;
BEGIN{$^W=0;}
use Net::DNS;
BEGIN{$^W=1;}
my $TRACE = 1;
my %config;
$config{me} = get_config('me') || hostname;
$config{timeout} = get_config('timeoutsmtpd') || 1200;
my (@commands) = qw(ehlo helo rset mail rcpt data help vrfy noop quit);
my (%commands); @commands{@commands} = ('') x @commands;
my %state;
respond(220, "$config{me} qpsmtpd $QPsmtpd::VERSION Service ready, send me all your stuff!");
my $remote_host = $ENV{TCPREMOTEHOST} || "[$ENV{TCPREMOTEIP}]";
$state{remote_info} = $ENV{TCPREMOTEINFO} ? "$ENV{TCPREMOTEINFO}\@$remote_host" : $remote_host;
$state{remote_ip} = $ENV{TCPREMOTEIP};
$SIG{ALRM} = sub { respond(421, "timeout pal, don't be so slow"); exit };
$state{dnsbl_blocked} = check_dnsbl($state{remote_ip});
my ($commands) = '';
alarm $config{timeout};
while (<STDIN>) {
alarm 0;
$_ =~ s/\r?\n$//s; # advanced chomp
warn "$$ dispatching $_\n" if $TRACE;
defined dispatch(split / +/, $_)
or respond(502, "command unrecognized: '$_'");
alarm $config{timeout};
}
sub dispatch {
my ($cmd) = lc shift;
respond(553, $state{dnsbl_blocked}), return 1
if $state{dnsbl_blocked} and ($cmd eq "mail" or $cmd eq "rcpt");
if (exists $commands{$cmd}) {
my ($result) = eval "&$cmd";
warn "$$ $@" if $@;
return $result if defined $result;
return fault("command '$cmd' failed unexpectedly");
}
return;
}
sub respond {
my ($code, @messages) = @_;
while (my $msg = shift @messages) {
my $line = $code . (@messages?"-":" ").$msg;
print "$line\r\n";
warn "$$ $line\n" if $TRACE;
}
return 1;
}
sub fault {
my ($msg) = shift || "program fault - command not performed";
return respond(451, "Fatal error - " . $msg);
}
sub helo {
my ($hello_host, @stuff) = @_;
return respond (503, "but you already said HELO ...") if $state{hello};
$state{hello} = "helo";
$state{hello_host} = $hello_host;
$state{transaction} = {};
respond(250, "$config{me} Hi $state{remote_info} [$state{remote_ip}]; I am so happy to meet you.");
}
sub ehlo {
my ($hello_host, @stuff) = @_;
return respond (503, "but you already said HELO ...") if $state{hello};
$state{hello} = "ehlo";
$state{hello_host} = $hello_host;
$state{transaction} = {};
respond(250,
"$config{me} Hi $state{remote_info} [$state{remote_ip}].",
"PIPELINING",
"8BITMIME",
(get_config('databytes') ? "SIZE ".get_config('databytes') : ()),
);
}
sub mail {
return respond(501, "syntax error in parameters") if $_[0] !~ m/^from:/i;
unless ($state{hello}) {
return respond(503, "please say hello first ...");
}
else {
my $from_parameter = join " ", @_;
warn "$$ full from_parameter: $from_parameter\n" if $TRACE;
my ($from) = ($from_parameter =~ m/^from:\s*(\S+)/i)[0];
warn "$$ from email address : $from\n" if $TRACE;
if ($from eq "<>") {
$from = Mail::Address->new("<>");
}
else {
$from = (Mail::Address->parse($from))[0];
}
return respond(501, "could not parse your mail from command") unless $from;
if ($from->format ne "<>" and get_config('rhsbl_zones')) {
my %rhsbl_zones = map { (split /\s+/, $_, 2)[0,1] } get_config('rhsbl_zones');
my $host = $from->host;
for my $rhsbl (keys %rhsbl_zones) {
respond("550", "Mail from $host rejected because it $rhsbl_zones{$rhsbl}"), return 1
if check_rhsbl($rhsbl, $host);
}
}
#warn "$$ getting mail from ",$from->format,"\n" if $TRACE;
respond(250, $from->format . ", sender OK - I always like getting mail from you!");
$state{transaction} = { from => $from };
}
}
sub rcpt {
return respond(501, "syntax error in parameters") unless $_[0] =~ m/^to:/i;
return(503, "Use MAIL before RCPT") unless $state{transaction}->{from};
my ($rcpt) = ($_[0] =~ m/to:(.*)/i)[0];
$rcpt = (Mail::Address->parse($rcpt))[0];
return respond(501, "could not parse recipient") unless $rcpt;
return respond(550, "will not relay for ". $rcpt->host) unless check_relay($rcpt->host);
push @{$state{transaction}->{rcpt}}, $rcpt;
respond(250, $rcpt->format . ", recipient OK");
}
sub data {
respond(503, "MAIL first"), return 1 unless $state{transaction}->{from};
respond(503, "RCPT first"), return 1 unless $state{transaction}->{rcpt};
respond(354, "go ahead");
my $buffer;
my $size = 0;
my $i = 0;
my $max_size = get_config('databytes') || 0;
while (<STDIN>) {
last if $_ eq ".\r\n";
$i++;
respond(451, "See http://develooper.com/code/qpsmtpd/barelf.html"), exit
if $_ eq ".\n";
unless ($max_size and $size > $max_size) {
s/\r\n$/\n/;
$buffer .= $_;
$size += length $_;
}
warn "$$ size is at $size\n" unless ($i % 300);
alarm $config{timeout};
}
respond(552, "Message too big!"),return 1 if $max_size and $size > $max_size;
# these bits inspired by Peter Samuels "qmail-queue wrapper"
pipe(MESSAGE_READER, MESSAGE_WRITER) or fault("Could not create message pipe"), exit;
pipe(ENVELOPE_READER, ENVELOPE_WRITER) or fault("Could not create envelope pipe"), exit;
my $oldfh =
select(MESSAGE_WRITER); $| = 1;
select(ENVELOPE_WRITER); $| = 1;
select($oldfh);
my $child = fork();
not defined $child and fault(451, "Could not fork"), exit;
if ($child) {
# Parent
close MESSAGE_READER or fault("close msg reader fault"),exit;
close ENVELOPE_READER or fault("close envelope reader fault"), exit;
print MESSAGE_WRITER "Received: from $state{remote_info} (HELO $state{hello_host}) ($state{remote_ip})\r\n";
print MESSAGE_WRITER " by $config{me} (qpsmtpd/$QPsmtpd::VERSION) with SMTP; ", scalar gmtime, " -0000\r\n";
print MESSAGE_WRITER $buffer;
close MESSAGE_WRITER;
my @rcpt = map { "T" . $_->address } @{$state{transaction}->{rcpt}};
my $from = "F".($state{transaction}->{from}->address|| "" );
print ENVELOPE_WRITER "$from\0", join("\0",@rcpt), "\0\0"
or respond(451,"Could not print addresses to queue"),exit;
close ENVELOPE_WRITER;
waitpid($child, 0);
my $exit_code = $? >> 8;
$exit_code and respond(451, "Unable to queue message ($exit_code)"), exit;
respond(250, "Message queued; it better be worth it.");
}
elsif (defined $child) {
# Child
close MESSAGE_WRITER or die "could not close message writer in parent";
close ENVELOPE_WRITER or die "could not close envelope writer in parent";
open(STDIN, "<&MESSAGE_READER") or die "b1";
open(STDOUT, "<&ENVELOPE_READER") or die "b2";
unless (exec '/var/qmail/bin/qmail-queue') {
die "should never be here!";
}
}
return 1;
}
sub rset {
$state{transaction} = {};
respond(250, "OK");
}
sub noop {
respond(250, "OK");
}
sub vrfy {
respond(252, "Just try sending a mail and we'll see how it turns out ...");
}
sub help {
respond(214,
"This is qpsmtpd $QPsmtpd::VERSION",
"See http://develooper.com/code/qpsmtpd/",
"To report bugs or whatnot, send mail to <ask\@perl.org>.");
}
sub quit {
respond(221, "$config{me} closing connection. Have a wonderful day");
exit;
}
sub check_rhsbl {
my ($rhsbl, $host) = @_;
return 0 unless $host;
warn "$$ checking $host in $rhsbl\n" if $TRACE > 2;
return 1 if ((gethostbyname("$host.$rhsbl"))[4]);
return 0;
}
sub check_dnsbl {
my $ip = shift;
my %dnsbl_zones = map { (split /\s+/, $_, 2)[0,1] } get_config('dnsbl_zones');
return unless %dnsbl_zones;
my $reversed_ip = join(".", reverse(split(/\./, $ip)));
my $res = new Net::DNS::Resolver;
for my $dnsbl (keys %dnsbl_zones) {
warn "$$ Checking $reversed_ip in $dnsbl ..." if $TRACE > 2;
my $query = $res->search("$reversed_ip.$dnsbl");
if ($query) {
my $a_record = 0;
foreach my $rr ($query->answer) {
$a_record = 1 if $rr->type eq "A";
next unless $rr->type eq "TXT";
return $rr->txtdata;
}
return "Blocked by $dnsbl" if $a_record;
}
else {
warn "$$ query for $reversed_ip.$dnsbl failed: ", $res->errorstring, "\n"
unless $res->errorstring eq "NXDOMAIN";
}
}
return "";
}
sub check_relay {
my $host = lc shift;
my @rcpt_hosts = get_config("rcpthosts");
for my $allowed (@rcpt_hosts) {
$allowed =~ s/^\s*(\S+)/$1/;
return 1 if $host eq lc $allowed;
return 1 if substr($allowed,0,1) eq "." and $host =~ m/\Q$allowed\E$/i;
}
return 0;
}
my %config_cache;
sub get_config {
my $config = shift;
#warn "$$ trying to get config for $config" if $TRACE;
return @{$config_cache{$config}} if $config_cache{$config};
my $configdir = '/var/qmail/control';
$configdir = "/home/smtpd/qpsmtpd/config" if (-e "/home/smtpd/qpsmtpd/config/$config");
open CF, "<$configdir/$config" or warn "$$ could not open configfile $config: $!", return;
my @config = <CF>;
chomp @config;
close CF;
#warn "$$ returning ",Data::Dumper->Dump([\@config], [qw(config)]);
$config_cache{$config} = \@config;
return wantarray ? @config : $config[0];
}
1;