Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1759866Ab3GaPKs (ORCPT ); Wed, 31 Jul 2013 11:10:48 -0400 Received: from forward-corp1g.mail.yandex.net ([95.108.253.251]:48225 "EHLO forward-corp1g.mail.yandex.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751803Ab3GaPKq (ORCPT ); Wed, 31 Jul 2013 11:10:46 -0400 X-Greylist: delayed 437 seconds by postgrey-1.27 at vger.kernel.org; Wed, 31 Jul 2013 11:10:46 EDT Authentication-Results: smtpcorp4.mail.yandex.net; dkim=pass header.i=@yandex-team.ru Message-ID: <51F9273B.2020408@yandex-team.ru> Date: Wed, 31 Jul 2013 19:03:23 +0400 From: Roman Gushchin User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:17.0) Gecko/20130623 Thunderbird/17.0.7 MIME-Version: 1.0 To: Eric Dumazet CC: "David S. Miller" , raise.sail@gmail.com, ebiederm@xmission.com, netdev@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] net: check net.core.somaxconn sysctl values References: <51F917CF.7010905@yandex-team.ru> <1375281457.10515.98.camel@edumazet-glaptop> In-Reply-To: <1375281457.10515.98.camel@edumazet-glaptop> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1966 Lines: 62 On 31.07.2013 18:37, Eric Dumazet wrote: > On Wed, 2013-07-31 at 17:57 +0400, Roman Gushchin wrote: >> It's possible to assign an invalid value to the net.core.somaxconn >> sysctl variable, because there is no checks at all. >> >> The sk_max_ack_backlog field of the sock structure is defined as >> unsigned short. Therefore, the backlog argument in inet_listen() >> shouldn't exceed USHRT_MAX. The backlog argument in the listen() syscall >> is truncated to the somaxconn value. So, the somaxconn value shouldn't >> exceed 65535 (USHRT_MAX). >> Also, negative values of somaxconn are meaningless. >> >> before: >> $ sysctl -w net.core.somaxconn=256 >> net.core.somaxconn = 256 >> $ sysctl -w net.core.somaxconn=65536 >> net.core.somaxconn = 65536 >> $ sysctl -w net.core.somaxconn=-100 >> net.core.somaxconn = -100 >> >> after: >> $ sysctl -w net.core.somaxconn=256 >> net.core.somaxconn = 256 >> $ sysctl -w net.core.somaxconn=65536 >> error: "Invalid argument" setting key "net.core.somaxconn" >> $ sysctl -w net.core.somaxconn=-100 >> error: "Invalid argument" setting key "net.core.somaxconn" >> >> Signed-off-by: Roman Gushchin >> --- >> net/core/sysctl_net_core.c | 6 +++++- >> 1 file changed, 5 insertions(+), 1 deletion(-) > > > We had a discussion about this one month ago, as Changli Gao posted a > patch. http://patchwork.ozlabs.org/patch/255460/ > > So proper credits would be nice ;) Ok :) > Based on a prior patch from Changli Gao > > Reported-by: Changli Gao > Suggested-by: Eric Dumazet > > Acked-by: Eric Dumazet > Thanks! PS I've forwarded your letter back to the lkml by mistake. Sorry) Regards, Roman -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/