/usr/sbin/p0f-analyzer is in amavisd-new 1:2.6.5-0ubuntu3.
This file is owned by root:root, with mode 0o755.
The actual contents of the file can be viewed below.
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#------------------------------------------------------------------------------
# This is p0f-analyzer.pl, a program to continuously read log reports from p0f
# utility, keep results in cache for a couple of minutes, and answer queries
# over UDP from some program (like amavisd-new) about collected data.
#
# Author: Mark Martinec <mark.martinec@ijs.si>
# Copyright (C) 2006 Mark Martinec, All Rights Reserved.
#
# Redistribution and use in source and binary forms, with or without
# modification, are permitted provided that the following conditions are met:
#
# * Redistributions of source code must retain the above copyright notice,
# this list of conditions and the following disclaimer.
# * Redistributions in binary form must reproduce the above copyright notice,
# this list of conditions and the following disclaimer in the documentation
# and/or other materials provided with the distribution.
# * Neither the name of the author, nor the name of the "Jozef Stefan"
# Institute, nor the names of contributors may be used to endorse or
# promote products derived from this software without specific prior
# written permission.
#
# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
# PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER
# OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
# EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
# PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
# OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
# WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
# OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
# ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
#
#(the license above is the new BSD license, and pertains to this program only)
#
# Patches and problem reports are welcome.
# The latest version of this program is available at:
# http://www.ijs.si/software/amavisd/
#------------------------------------------------------------------------------
use strict;
use re 'taint';
use Errno qw(EAGAIN EINTR);
use Socket;
use vars qw($VERSION);
$VERSION = '1.400';
# Example usage:
# p0f -i bge0 -l 'tcp dst port 25' 2>&1 | p0f-analyzer.pl 2345
#
# In the p0f filter expression above specify an IP address of this host where
# your MTA is listening for incoming mail, in place of host.example.com above.
# Match the UDP port number (like 2345 above) with the port to which a client
# will be sending queries ($os_fingerprint_method in amavisd.conf).
# argument should be a free UDP port where queries will be accepted on
$ARGV[0] =~ /^[0-9]+\z/ or die <<'EOD';
Specify a valid UDP port as an argument.
Usage:
p0f-analyzer.pl <udp-port>
Example usage:
p0f -l 'tcp dst port 25' 2>&1 | p0f-analyzer.pl 2345
EOD
my($port) = untaint($ARGV[0]);
# my($bind_addr) = '0.0.0.0'; # bind to all IPv4 interfaces
my($bind_addr) = '127.0.0.1'; # bind just to a loopback interface
my(@inet_acl) = qw( 127.0.0.1 ); # list of IP addresses from which queries
# will be accepted, others are ignored
my($retention_time) = 10*60; # time to keep collected information in cache
my($debug) = 0; # nonzero enables log messages to STDERR
do_log(1, "p0f-analyzer version %s starting", $VERSION);
do_log(1, "listening on UDP port %s, allowed queries from: %s",
$port, join(", ",@inet_acl));
socket(S, PF_INET, SOCK_DGRAM, getprotobyname('udp')) or die "socket: $!";
my($packed_addr);
$packed_addr = inet_aton($bind_addr)
or die "inet_aton: bad IP address [$bind_addr]: $!";
bind(S, sockaddr_in($port,$packed_addr))
or die "binding to [$bind_addr] failed: $!";
my($fn_sock) = fileno(S); my($fn_stdin) = fileno(STDIN);
my($rin,$rout); $rin = '';
vec($rin,$fn_sock,1) = 1; vec($rin,$fn_stdin,1) = 1;
my(%src); my($cnt_since_cleanup) = 0;
binmode(STDIN) or die "Can't set STDIN binmode: $!";
for (;;) {
my($nfound,$timeleft) = select($rout=$rin, undef, undef, undef);
my($now) = time;
if (vec($rout,$fn_sock,1)) {
my($port,$iaddr,$paddr,$clientaddr); my($inbuf);
$paddr = recv(S,$inbuf,64,0);
if (!defined($paddr)) {
if ($!==EAGAIN || $!==EINTR) {
# false alarm, nothing can be read
} else {
die "recv: $!";
}
} else {
($port,$iaddr) = sockaddr_in($paddr) if $paddr ne '';
$clientaddr = inet_ntoa($iaddr) if defined $iaddr;
if (!defined($clientaddr)) {
do_log(1, "query from unknown client");
} elsif (!grep {$_ eq $clientaddr} @inet_acl) {
do_log(1, "query from non-approved client: %s:%s",$clientaddr,$port);
} elsif ($port < 1024 || $port == 2049 || $port > 65535) {
do_log(1, "query from questionable port: %s:%s", $clientaddr,$port);
} elsif ($inbuf !~ /^([^ ]+) (.*)$/s) {
do_log(1, "invalid query syntax from %s:%s", $clientaddr,$port);
} else {
my($query,$nonce) = ($1,$2); my($src_ip,$src_port);
if ($query =~ /^\d{1,3}\.\d{1,3}\.\d{1,3}\.\d{1,3}\z/s) {
$src_ip = $query; $src_port = 0; # old style query
} elsif ($query =~ /^ \[ ([^\]]*) \] (?: : (\d{1,5}) )? \z/xs) {
$src_ip = $1; $src_port = $2;
if ($src_ip =~ /^\d{1,3}\.\d{1,3}\.\d{1,3}\.\d{1,3}\z/) {
# IPv4
} elsif ($src_ip =~ /^ (?: IPv6: )? [0-9a-f]{0,4}
(?: : [0-9a-f]{0,4} | \. [0-9]{1,3} ){2,8} \z/xsi) {
$src_ip =~ s/^IPv6://i;
} else { undef $src_ip }
}
$src_port = 0 if !defined($src_port);
if (length($nonce) > 1024) {
do_log(1, "invalid query from %s:%s, nonce too long: %d chrs",
$clientaddr,$port,length($nonce));
} elsif ($nonce !~ /^([\040-\177].*)\z/s) {
do_log(1, "invalid query from %s:%s, forbidden char in nonce",
$clientaddr,$port);
} elsif (!defined($src_ip) || $src_port > 65535) {
do_log(1, "invalid query from %s:%s, bad IP address or port: %s",
$clientaddr,$port,$query);
} else {
do_log(1, "query from %s:%s: %s", $clientaddr,$port,$inbuf);
my($resp) = '';
if (exists($src{$src_ip})) {
if ($src_port > 0) { # source port known, must match exactly
$resp = $src{"[$src_ip]:$src_port"}{d}
if exists $src{"[$src_ip]:$src_port"};
} else { # source port not known, find the closest match
for my $e (@{$src{$src_ip}}) {
if ($resp eq '') { $resp = $e->{d} }
elsif ($e->{d} eq $resp) {}
else { # keep the longest common string head
my($j); my($resp_l) = length($resp);
for ($j=0; $j<$resp_l; $j++)
{ last if substr($e->{d},$j,1) ne substr($resp,$j,1) }
if ($j < $resp_l) {
# do_log(1, "TRUNCATED to %d: %s %s => /%s/",
# $j, $resp, $e->{d}, substr($resp,0,$j));
$resp = substr($resp,0,$j);
}
}
last;
}
}
}
$resp = $query.' '.$nonce.' '.$resp;
do_log(1, "response to %s:%s: %s", $clientaddr,$port,$resp);
defined(send(S, $resp."\015\012", 0, $paddr)) or die "send: $!";
}
}
}
}
if (vec($rout,$fn_stdin,1)) {
$cnt_since_cleanup++; my($line); $! = 0;
my($nbytes) = sysread(STDIN,$line,1024);
if (!defined($nbytes)) {
if ($!==EAGAIN || $!==EINTR) {
# false alarm, nothing can be read
} else {
die "Read: $!";
}
} elsif ($nbytes < 1) { # sysread returns 0 at eof
last; # eof
} else {
chomp($line);
local($1,$2,$3,$4,$5,$6);
$line =~ /^(\d+\.\d+\.\d+\.\d+):(\d+)[ -]*(.*)
\ ->\ (\d+\.\d+\.\d+\.\d+):(\d+)\s*(.*)$/x or next;
my($src_ip,$src_port,$src_t,$dst_ip,$dst_port,$src_d) =
($1,$2,$3,$4,$5,$6);
my($descr) = "$src_t, $src_d";
my($entry) = { t=>$now, p=>$src_port, c=>1, d=>$descr };
$src{"[$src_ip]:$src_port"} = $entry;
if (!exists($src{$src_ip})) {
do_log(2, "first: [%s]:%s %.70s", $src_ip,$src_port,$descr);
$src{$src_ip} = [ $entry ];
} else {
my($found) = 0;
for my $e (@{$src{$src_ip}}) {
if ($e->{d} eq $descr) {
$e->{c}++; $e->{p} = '*'; $e->{t} = $now, $found = 1;
do_log(2, "deja-vu: [%s]:%s, cnt=%d %.70s",
$src_ip,$src_port,$e->{c},$descr);
last;
}
}
if (!$found) {
push(@{$src{$src_ip}}, $entry);
do_log(2, "stored: [%s]:%d %.70s", $src_ip,$src_port,$descr);
}
}
}
if ($cnt_since_cleanup > 50) {
for my $k (keys %src) {
if (ref($src{$k}) ne 'ARRAY') {
if ($src{$k}{t} + $retention_time < $now) {
do_log(2, "EXPIRED: %s, age = %d s", $k, $now - $src{$k}{t});
delete $src{$k};
}
} else {
my(@kept) = grep { $_->{t} + $retention_time >= $now } @{$src{$k}};
if (!@kept) {
do_log(2, "EXPIRED: %s, age = %d s", $k, $now - $src{$k}[0]{t});
delete $src{$k};
} elsif (@kept != @{$src{$k}}) {
do_log(2, "SHRUNK: %s, %d -> %d",
$k, scalar(@{$src{$k}}), scalar(@kept));
@{$src{$k}} = @kept;
}
}
}
$cnt_since_cleanup = 0;
}
}
}
do_log(1, "normal termination");
exit 0;
# Return untainted copy of a string (argument can be a string or a string ref)
sub untaint($) {
no re 'taint';
my($str);
if (defined($_[0])) {
local($1); # avoid Perl taint bug: tainted global $1 propagates taintedness
$str = $1 if (ref($_[0]) ? ${$_[0]} : $_[0]) =~ /^(.*)\z/s;
}
$str;
}
# write log entry
sub do_log($$;@) {
my($level,$errmsg,@args) = @_;
if ($level <= $debug) {
$errmsg = sprintf($errmsg,@args) if @args;
print STDERR $errmsg,"\n";
}
1;
}
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