From mboxrd@z Thu Jan 1 00:00:00 1970 From: Andi Kleen Subject: Re: [PATCH] Re: [PATCH] drivers/net: remove network drivers' last few uses of IRQF_SAMPLE_RANDOM Date: Sun, 18 May 2008 12:08:42 +0200 Message-ID: <4830002A.4020608@firstfloor.org> References: <20080515142154.0595e475@core> <482C7DA3.1090809@garzik.org> <482C953A.4080205@garzik.org> <87abirytxj.fsf@basil.nowhere.org> <20080516105635.6cb1f505@core> <482D5FC5.2070103@firstfloor.org> <20080516121239.GA9627@gondor.apana.org.au> <482DB568.1040704@firstfloor.org> <20080517010136.GA15102@gondor.apana.org.au> <482EBAA8.3040506@firstfloor.org> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Cc: Herbert Xu , Alan Cox , Jeff Garzik , netdev@vger.kernel.org, linux-kernel@vger.kernel.org, Andrew Morton , "Brandeburg, Jesse" , tpmdd-devel@lists.sourceforge.net, tpm@selhorst.net To: Chris Peterson Return-path: Received: from one.firstfloor.org ([213.235.205.2]:57181 "EHLO one.firstfloor.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751783AbYERKIv (ORCPT ); Sun, 18 May 2008 06:08:51 -0400 In-Reply-To: Sender: netdev-owner@vger.kernel.org List-ID: Chris Peterson wrote: >> Would people be ok with kernel auto-feeding for /dev/urandom only? I've >> been pondering that and I think that would work just as well in practice >> given the facts above. Then you would still only get blocking >> /dev/random with the user daemon, but that won't matter because all >> the usual users don't rely on thatanyways. > > Andi, can you please clarify what you mean by "auto-feeding > /dev/urandom only" and "only get blocking /dev/random with the user > daemon"? Are you suggesting that the kernel provides /dev/urandom and > a userspace daemon (e.g. EGD) provides /dev/random? What I meant was "only getting working blocking /dev/random with the user mode daemon". / The kernel would still provide /dev/random. But on systems without much entropy (which is pretty common) it will block often and be unusable unless you run some obscure user space daemons which regularly refeed /dev/random from hw_random and stops doing that if the FIPS test fails and makes /dev/random unusable again. > Also, if crypto apps like ssh and openssl use on "insecure" > /dev/urandom, then who actually relies on /dev/random? For comparison, > FreeBSD does not even (AFAIK) have /dev/urandom. FreeBSD's /dev/random > is nonblocking (like Linux's /dev/urandom) and includes network > entropy. It's sad to say, but their implementation makes more sense than Linux's (including the feeding in of network data) I suspect that's the main reason I actually found that many /dev/random users as I found during my research. -Andi