From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754202Ab1AFA3s (ORCPT ); Wed, 5 Jan 2011 19:29:48 -0500 Received: from kroah.org ([198.145.64.141]:35679 "EHLO coco.kroah.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754181Ab1AFA3p (ORCPT ); Wed, 5 Jan 2011 19:29:45 -0500 X-Mailbox-Line: From gregkh@clark.site Wed Jan 5 16:23:01 2011 Message-Id: <20110106002301.781715875@clark.site> User-Agent: quilt/0.48-11.2 Date: Wed, 05 Jan 2011 16:22:33 -0800 From: Greg KH To: linux-kernel@vger.kernel.org, stable@kernel.org Cc: stable-review@kernel.org, torvalds@linux-foundation.org, akpm@linux-foundation.org, alan@lxorguk.ukuu.org.uk, "David S. Miller" Subject: [054/152] tcp: Increase TCP_MAXSEG socket option minimum. In-Reply-To: <20110106002500.GA3172@kroah.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 2.6.36-stable review patch. If anyone has any objections, please let us know. ------------------ From: David S. Miller [ Upstream commit 7a1abd08d52fdeddb3e9a5a33f2f15cc6a5674d2 ] As noted by Steve Chen, since commit f5fff5dc8a7a3f395b0525c02ba92c95d42b7390 ("tcp: advertise MSS requested by user") we can end up with a situation where tcp_select_initial_window() does a divide by a zero (or even negative) mss value. The problem is that sometimes we effectively subtract TCPOLEN_TSTAMP_ALIGNED and/or TCPOLEN_MD5SIG_ALIGNED from the mss. Fix this by increasing the minimum from 8 to 64. Reported-by: Steve Chen Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman --- net/ipv4/tcp.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/net/ipv4/tcp.c +++ b/net/ipv4/tcp.c @@ -2246,7 +2246,7 @@ static int do_tcp_setsockopt(struct sock /* Values greater than interface MTU won't take effect. However * at the point when this call is done we typically don't yet * know which interface is going to be used */ - if (val < 8 || val > MAX_TCP_WINDOW) { + if (val < 64 || val > MAX_TCP_WINDOW) { err = -EINVAL; break; }