From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S272276AbTHIIJm (ORCPT ); Sat, 9 Aug 2003 04:09:42 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S272277AbTHIIJl (ORCPT ); Sat, 9 Aug 2003 04:09:41 -0400 Received: from pizda.ninka.net ([216.101.162.242]:58020 "EHLO pizda.ninka.net") by vger.kernel.org with ESMTP id S272276AbTHIIJk (ORCPT ); Sat, 9 Aug 2003 04:09:40 -0400 Date: Sat, 9 Aug 2003 01:04:18 -0700 From: "David S. Miller" To: Matt Mackall Cc: linux-kernel@vger.kernel.org, akpm@osdl.org, jmorris@intercode.com.au Subject: Re: [RFC][PATCH] Make cryptoapi non-optional? Message-Id: <20030809010418.3b01b2eb.davem@redhat.com> In-Reply-To: <20030809074459.GQ31810@waste.org> References: <20030809074459.GQ31810@waste.org> X-Mailer: Sylpheed version 0.9.2 (GTK+ 1.2.6; sparc-unknown-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Sat, 9 Aug 2003 02:44:59 -0500 Matt Mackall wrote: > The attached (lightly tested) patch gets rid of the SHA in the > /dev/random code and replaces it with cryptoapi, leaving us with just > one SHA implementation. ... > __u32 secure_tcp_syn_cookie(__u32 saddr, __u32 daddr, __u16 sport, > __u16 dport, __u32 sseq, __u32 count, __u32 data) ... > + tfm = crypto_alloc_tfm("sha1", 0); secure_tcp_syn_cookie() is called from software interrupt context, therefore it may not sleep. So you cannot call crypto_alloc_tfm() here, which can sleep. Not to mention that calling crypto_alloc_tfm() for every TCP connection creation is absurdly expensive. Same thing in check_tcp_syn_cookie(). Also, same problem exists with extract_entropy() which also must be callable from software interrupt context, and thus the crypto_alloc_tfm() alloc calls you added there are illegal too. This patch needs tons of work.