Append random garbage to pings so they have different lengths

4 files changed, 42 insertions, 7 deletions

diff --git a/Echolot/Chain.pm b/Echolot/Chain.pm
index 63e4a5b..2f2ca52 100644
--- a/Echolot/Chain.pm
+++ b/Echolot/Chain.pm
@@ -1,7 +1,7 @@
 package Echolot::Chain;
 
 # (c) 2002 Peter Palfrader <peter@palfrader.org>
-# $Id: Chain.pm,v 1.5 2003/02/16 09:09:57 weasel Exp $
+# $Id: Chain.pm,v 1.6 2003/02/16 10:07:27 weasel Exp $
 #
 
 =pod
@@ -86,7 +86,8 @@ sub do_chainping($$$$$$$) {
 		"type2: $type2\n".
 		"key2: $key2\n".
 		"sent: $now\n".
-		"mac: $mac\n";
+		"mac: $mac\n".
+		Echolot::Tools::make_garbage();
 	$body = Echolot::Tools::crypt_symmetrically($body, 'encrypt');
 		
 	my $to = Echolot::Tools::make_address('chainping');
diff --git a/Echolot/Config.pm b/Echolot/Config.pm
index 5696d80..2698dd4 100644
--- a/Echolot/Config.pm
+++ b/Echolot/Config.pm
@@ -1,7 +1,7 @@
 package Echolot::Config;
 
 # (c) 2002 Peter Palfrader <peter@palfrader.org>
-# $Id: Config.pm,v 1.54 2003/02/16 09:13:51 weasel Exp $
+# $Id: Config.pm,v 1.55 2003/02/16 10:07:27 weasel Exp $
 #
 
 =pod
@@ -64,6 +64,7 @@ sub init($) {
 		# System Specific Options
 		recipient_delimiter         => '+',
 		dev_random                  => '/dev/random',
+		dev_urandom                 => '/dev/urandom',
 		sendmail                    => '/usr/sbin/sendmail',
 
 		# Magic Numbers
@@ -112,13 +113,16 @@ sub init($) {
 		check_resurrection_ttl      => 8, # check_resurrection seconds (weeks)
 		prospective_addresses_ttl   => 5*24*60*60, # 5 days
 		reliable_auto_add_min       => 3, # 3 remailes need to list new address
-		
+
 		expire_keys                 => 5*24*60*60, # 5 days
 		expire_confs                => 5*24*60*60, # 5 days
 		expire_pings                => 12*24*60*60, # 12 days
 		expire_thesaurus            => 21*24*60*60, # 21 days
 		expire_chainpings           => 12*24*60*60, # 12 days
 
+		random_garbage              => 8192,
+
+
 		# Directories and files
 		mailin                      => 'mail',
 		mailerrordir                => 'mail-errors',
diff --git a/Echolot/Pinger.pm b/Echolot/Pinger.pm
index dcb03cc..792cb1d 100644
--- a/Echolot/Pinger.pm
+++ b/Echolot/Pinger.pm
@@ -1,7 +1,7 @@
 package Echolot::Pinger;
 
 # (c) 2002 Peter Palfrader <peter@palfrader.org>
-# $Id: Pinger.pm,v 1.24 2003/02/14 04:57:45 weasel Exp $
+# $Id: Pinger.pm,v 1.25 2003/02/16 10:07:27 weasel Exp $
 #
 
 =pod
@@ -71,7 +71,8 @@ sub do_ping($$$) {
 		"type: $type\n".
 		"key: $key\n".
 		"sent: $now\n".
-		"mac: $mac\n";
+		"mac: $mac\n".
+		Echolot::Tools::make_garbage();
 	$body = Echolot::Tools::crypt_symmetrically($body, 'encrypt');
 		
 	my $to = Echolot::Tools::make_address('ping');
diff --git a/Echolot/Tools.pm b/Echolot/Tools.pm
index 86adb91..2094d5c 100644
--- a/Echolot/Tools.pm
+++ b/Echolot/Tools.pm
@@ -1,7 +1,7 @@
 package Echolot::Tools;
 
 # (c) 2002 Peter Palfrader <peter@palfrader.org>
-# $Id: Tools.pm,v 1.15 2003/02/15 11:43:41 weasel Exp $
+# $Id: Tools.pm,v 1.16 2003/02/16 10:07:27 weasel Exp $
 #
 
 =pod
@@ -308,6 +308,35 @@ sub crypt_symmetrically($$) {
 	return $result;
 };
 
+sub make_garbage() {
+
+	my $file = Echolot::Config::get()->{'dev_urandom'};
+	open(FH, $file) or
+		Echolot::Log::warn("Cannot open $file: $!."),
+		return "";
+	my $random = '';
+	my $want = rand(int(Echolot::Config::get()->{'random_garbage'} / 2));
+	my $i = 0;
+	while ($want > 0) {
+		my $buf;
+		$want -= read(FH, $buf, $want);
+		$random .= $buf;
+		($i++ > 15 && $want > 0) and
+			Echolot::Log::warn("Could not get enough garbage (still missing $want."),
+			last;
+	};
+	close (FH) or
+		Echolot::Log::warn("Cannot close $file: $!.");
+	
+	$random = unpack("H*", $random);
+	$random = join "\n", grep { $_ ne '' } (split /(.{64})/, $random);
+	$random = "----- BEGIN GARBAGE' -----\n".
+		$random."\n".
+		"----- BEGIN GARBAGE' -----\n";
+	
+	return $random;
+};
+
 1;
 
 # vim: set ts=4 shiftwidth=4: