From: Clemens Ladisch Subject: Re: [RFC PATCH] char: random: stir the output pools differently when the random_write lenght allows splitting the seed Date: Fri, 10 Jan 2014 09:13:57 +0100 Message-ID: <52CFABC5.5030806@ladisch.de> References: <42f6dc88535d5ecdab13b1376db7ccbbbc550600.1389297772.git.aquini@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Cc: Arnd Bergmann , Greg Kroah-Hartman , linux-kernel@vger.kernel.org, linux-crypto@vger.kernel.org, Stephan Mueller To: Rafael Aquini , Theodore Ts'o Return-path: Received: from smtprelay03.ispgateway.de ([80.67.31.41]:60292 "EHLO smtprelay03.ispgateway.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751750AbaAJIYQ (ORCPT ); Fri, 10 Jan 2014 03:24:16 -0500 In-Reply-To: <42f6dc88535d5ecdab13b1376db7ccbbbc550600.1389297772.git.aquini@redhat.com> Sender: linux-crypto-owner@vger.kernel.org List-ID: Rafael Aquini wrote: > This patch introduces changes to the random_write method so it can split the > given seed and completely stir the output pools with different halves of it, > when seed lenght allows us doing so. > > - ret = write_pool(&blocking_pool, buffer, count); > + ret = write_pool(pool1, buffer, count1); > if (ret) > return ret; > - ret = write_pool(&nonblocking_pool, buffer, count); > + ret = write_pool(pool2, buffer + offset, count2); Doesn't this assume that both halves of the buffer contain some (uncredited) entropy? In other words, wouldn't this result in worse randomness for pool2 if the second half of the buffer contains just zero padding? Regards, Clemens