From owner-cvs-all  Sun Feb 23 11: 4:26 2003
Delivered-To: cvs-all@freebsd.org
Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125])
	by hub.freebsd.org (Postfix) with ESMTP
	id 4B05037B405; Sun, 23 Feb 2003 11:04:24 -0800 (PST)
Received: from repoman.freebsd.org (repoman.freebsd.org [216.136.204.115])
	by mx1.FreeBSD.org (Postfix) with ESMTP
	id BBF1943FA3; Sun, 23 Feb 2003 11:04:23 -0800 (PST)
	(envelope-from silby@FreeBSD.org)
Received: from repoman.freebsd.org (localhost [127.0.0.1])
	by repoman.freebsd.org (8.12.6/8.12.6) with ESMTP id h1NJ4N0U094050;
	Sun, 23 Feb 2003 11:04:23 -0800 (PST)
	(envelope-from silby@repoman.freebsd.org)
Received: (from silby@localhost)
	by repoman.freebsd.org (8.12.6/8.12.6/Submit) id h1NJ4NCu094049;
	Sun, 23 Feb 2003 11:04:23 -0800 (PST)
Message-Id: <200302231904.h1NJ4NCu094049@repoman.freebsd.org>
From: Mike Silbersack <silby@FreeBSD.org>
Date: Sun, 23 Feb 2003 11:04:23 -0800 (PST)
To: src-committers@FreeBSD.org, cvs-src@FreeBSD.org,
	cvs-all@FreeBSD.org
Subject: cvs commit: src/sys/netinet tcp_syncache.c
X-FreeBSD-CVS-Branch: HEAD
Sender: owner-cvs-all@FreeBSD.ORG
Precedence: bulk
List-ID: <cvs-all.FreeBSD.ORG>
List-Archive: <http://docs.freebsd.org/mail/> (Web Archive)
List-Help: <mailto:majordomo@FreeBSD.ORG?subject=help> (List Instructions)
List-Subscribe: <mailto:majordomo@FreeBSD.ORG?subject=subscribe%20cvs-all>
List-Unsubscribe: <mailto:majordomo@FreeBSD.ORG?subject=unsubscribe%20cvs-all>
X-Loop: FreeBSD.ORG

silby       2003/02/23 11:04:23 PST

  Modified files:
    sys/netinet          tcp_syncache.c 
  Log:
  Improve the security and performance of syncookies:
  
  Security improvements:
  - Increase the size of each syncookie secret from 32 to 128 bits
    in order to make brute force attacks on the secrets much more
    difficult.
  - Always return the lowest order dword from the MD5 hash; this
    allows us to expose 2 more bits of the cookie and makes ACK
    floods which seek to guess the cookie value more difficult.
  
  Performance improvements:
  - Increase the lifetime of each syncookie from 4 seconds to 16
    seconds.  This increases the usefulness of syncookies during
    an attack.
  - From Yahoo!: Reduce the number of calls to MD5Update; this
    results in a ~17% increase in cookie generation time here.
  
  Reviewed by:    hsu, jayanth, jlemon, nectar
  MFC After:      15 seconds
  
  Revision  Changes    Path
  1.38      +47 -26    src/sys/netinet/tcp_syncache.c

To Unsubscribe: send mail to majordomo@FreeBSD.org
with "unsubscribe cvs-all" in the body of the message