From: Sasha Levin Subject: Re: [PATCH] random: add blocking facility to urandom Date: Thu, 08 Sep 2011 00:38:31 +0300 Message-ID: <1315431511.3576.66.camel@lappy> References: <1314974248-1511-1-git-send-email-jarod@redhat.com> <201109071656.49758.sgrubb@redhat.com> <1315429827.3576.61.camel@lappy> <201109071728.31162.sgrubb@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Cc: Ted Ts'o , Jarod Wilson , linux-crypto@vger.kernel.org, Matt Mackall , Neil Horman , Herbert Xu , Stephan Mueller , lkml To: Steve Grubb Return-path: In-Reply-To: <201109071728.31162.sgrubb@redhat.com> Sender: linux-kernel-owner@vger.kernel.org List-Id: linux-crypto.vger.kernel.org On Wed, 2011-09-07 at 17:28 -0400, Steve Grubb wrote: > On Wednesday, September 07, 2011 05:10:27 PM Sasha Levin wrote: > > > > > > Something similar probably happens for getting junk on disks before > > > > > > creating an encrypted filesystem on top of them. > > > > > > > > > > During system install, this sysctl is not likely to be applied. > > > > > > > > It may happen at any time you need to create a new filesystem, which > > > > won't necessarily happen during system install. > > > > > > > > See for example the instructions on how to set up a LUKS filesystem: > > > > https://wiki.archlinux.org/index.php/System_Encryption_with_LUKS#Prepar > > > > atio n_and_mapping > > > > > > Those instructions might need to be changed. That is one way of many to > > > get random numbers on the disk. Anyone really needing the security to > > > have the sysctl on will also probably accept that its doing its job and > > > keeping the numbers random. Again, no effect unless you turn it on. > > > > There are bunch of other places that would need to be changed in that > > case :) > > > > Why not implement it as a user mode CUSE driver that would > > wrap /dev/urandom and make it behave any way you want to? why push it > > into the kernel? > > For one, auditing does not work for FUSE or things like that. We have to be able to > audit who is using what. Then there are the FIPS-140 requirements and this will spread > it. There are problems sending crypto audit events from user space, too. auditd doesn't work with FUSE? afaik it should, FUSE is a filesystem like any other. -- Sasha.