From mboxrd@z Thu Jan 1 00:00:00 1970 From: Pablo Neira Ayuso Subject: Re: [PATCH 01/12] netfilter: avoid get_random_bytes calls Date: Mon, 6 Jan 2014 13:58:23 +0100 Message-ID: <20140106125823.GA8076@localhost> References: <1388963586-5049-1-git-send-email-pablo@netfilter.org> <1388963586-5049-2-git-send-email-pablo@netfilter.org> <20140105234157.GB29910@order.stressinduktion.org> <20140106115436.GE28854@breakpoint.cc> <20140106124340.GC4611@order.stressinduktion.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: Florian Westphal , netfilter-devel@vger.kernel.org, davem@davemloft.net, netdev@vger.kernel.org To: Hannes Frederic Sowa Return-path: Content-Disposition: inline In-Reply-To: <20140106124340.GC4611@order.stressinduktion.org> Sender: netdev-owner@vger.kernel.org List-Id: netfilter-devel.vger.kernel.org On Mon, Jan 06, 2014 at 01:43:40PM +0100, Hannes Frederic Sowa wrote: [...] > > > Hmm, some of them look like good candidates for net_get_random_once. I don't > > > see such a problem with draining entropy pool, especially as they don't run > > > that early and they don't request so many random bits. > > > > I specifically did not use net_get_random_once once because checkentry is > > not a hotpath. > > > > I don't see why get_random_bytes use increases the security margin, especially > > considering none of these hashes have periodic run-time rehashing? > > > > But sure, if you think this change is a problem, Pablo can just revert it. > > I don't know if it is a real problem. Most of the time the initial seed > should be enough, but I guess get_random_bytes would still be a more > defensive choice. I would have used it. ;) OK, I have reverted this patch, thanks.