From mboxrd@z Thu Jan 1 00:00:00 1970 From: David Miller Subject: Re: [PATCH] drivers/net: Remove IRQF_SAMPLE_RANDOM flag from network drivers Date: Wed, 30 Mar 2011 22:28:32 -0700 (PDT) Message-ID: <20110330.222832.193698433.davem@davemloft.net> References: <1301365651-9106-1-git-send-email-martinez.javier@gmail.com> Mime-Version: 1.0 Content-Type: Text/Plain; charset=us-ascii Content-Transfer-Encoding: 7bit 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 To: martinez.javier@gmail.com Return-path: In-Reply-To: <1301365651-9106-1-git-send-email-martinez.javier@gmail.com> Sender: linux-kernel-owner@vger.kernel.org List-Id: netdev.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!