From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932126Ab1CaF3M (ORCPT ); Thu, 31 Mar 2011 01:29:12 -0400 Received: from 74-93-104-97-Washington.hfc.comcastbusiness.net ([74.93.104.97]:47079 "EHLO sunset.davemloft.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754038Ab1CaF3K (ORCPT ); Thu, 31 Mar 2011 01:29:10 -0400 Date: Wed, 30 Mar 2011 22:28:32 -0700 (PDT) Message-Id: <20110330.222832.193698433.davem@davemloft.net> To: martinez.javier@gmail.com Cc: bhutchings@solarflare.com, ffainelli@freebox.fr, eric.dumazet@gmail.com, netdev@vger.kernel.org, kernel-janitors@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] drivers/net: Remove IRQF_SAMPLE_RANDOM flag from network drivers From: David Miller In-Reply-To: <1301365651-9106-1-git-send-email-martinez.javier@gmail.com> References: <1301365651-9106-1-git-send-email-martinez.javier@gmail.com> X-Mailer: Mew version 6.3 on Emacs 23.1 / Mule 6.0 (HANACHIRUSATO) Mime-Version: 1.0 Content-Type: Text/Plain; charset=us-ascii Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Javier Martinez Canillas Date: Tue, 29 Mar 2011 04:27:31 +0200 > The IRQF_SAMPLE_RANDOM flag is marked as deprecated and will be removed. > > Every input point to the kernel's entropy pool have to better document the > type of entropy source it is. > > drivers/char/random.c now implements a set of interfaces that can be used for > devices to collect enviromental noise. IRQF_SAMPLE_RANDOM will be replaced > with these add_*_randomness exported functions. > > Network drivers are not a good source of entropy. They use as a source of > entropy essentially a remote host. Which means that the source of entropy can > be potentially controlled by an attacker. Also, with heavy workloads the > entropy decreases due to less hardware interrupts happening thanks to irq > mitigation and NAPI. > > If a system relies in its network interface as a entropy source it has a false > sense of security. Systems that don't have devices whose drivers are good > sources of entropy, should either use a hardware random number generator or > feed the kernel's entropy pool from userspace using other sources of entropy > such as EGD, video_entropyd, timer_entropyd and audio-entropyd. > > Signed-off-by: Javier Martinez Canillas Appied to net-next-2.6, thanks!