From mboxrd@z Thu Jan 1 00:00:00 1970 From: David Miller Subject: Re: [PATCH net] net: sctp: fix permissions for rto_alpha and rto_beta knobs Date: Sun, 15 Jun 2014 01:18:30 -0700 (PDT) Message-ID: <20140615.011830.1834645975843111936.davem@davemloft.net> References: <1402786754-16807-1-git-send-email-dborkman@redhat.com> Mime-Version: 1.0 Content-Type: Text/Plain; charset=us-ascii Content-Transfer-Encoding: 7bit Cc: netdev@vger.kernel.org, linux-sctp@vger.kernel.org, vyasevich@gmail.com To: dborkman@redhat.com Return-path: Received: from shards.monkeyblade.net ([149.20.54.216]:39131 "EHLO shards.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750993AbaFOISc (ORCPT ); Sun, 15 Jun 2014 04:18:32 -0400 In-Reply-To: <1402786754-16807-1-git-send-email-dborkman@redhat.com> Sender: netdev-owner@vger.kernel.org List-ID: From: Daniel Borkmann Date: Sun, 15 Jun 2014 00:59:14 +0200 > Commit 3fd091e73b81 ("[SCTP]: Remove multiple levels of msecs > to jiffies conversions.") has silently changed permissions for > rto_alpha and rto_beta knobs from 0644 to 0444. The purpose of > this was to discourage users from tweaking rto_alpha and > rto_beta knobs in production environments since they are key > to correctly compute rtt/srtt. > > RFC4960 under section 6.3.1. RTO Calculation says regarding > rto_alpha and rto_beta under rule C3 and C4: ... > While it is discouraged to adjust rto_alpha and rto_beta > and not further specified how to adjust them, the RFC also > doesn't explicitly forbid it, but rather gives a RECOMMENDED > default value (rto_alpha=3, rto_beta=2). We have a couple > of users relying on the old permissions before they got > changed. That said, if someone really has the urge to adjust > them, we could allow it with a warning in the log. > > Fixes: 3fd091e73b81 ("[SCTP]: Remove multiple levels of msecs to jiffies conversions.") > Signed-off-by: Daniel Borkmann This permission change seemed unintentional, and doesn't make much sense anyways to me. So I'm applying this, thanks Daniel.