Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753123AbeAFMYt (ORCPT + 1 other); Sat, 6 Jan 2018 07:24:49 -0500 Received: from www.llwyncelyn.cymru ([82.70.14.225]:55012 "EHLO fuzix.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752864AbeAFMYr (ORCPT ); Sat, 6 Jan 2018 07:24:47 -0500 Date: Sat, 6 Jan 2018 12:23:47 +0000 From: Alan Cox To: Greg KH Cc: Dan Williams , linux-kernel@vger.kernel.org, linux-arch@vger.kernel.org, Hideaki YOSHIFUJI , netdev@vger.kernel.org, peterz@infradead.org, Alexey Kuznetsov , tglx@linutronix.de, torvalds@linux-foundation.org, "David S. Miller" , Elena Reshetova , alan@linux.intel.com Subject: Re: [PATCH 14/18] ipv4: prevent bounds-check bypass via speculative execution Message-ID: <20180106122347.7a5c8ee6@alans-desktop> In-Reply-To: <20180106090154.GE4380@kroah.com> References: <151520099201.32271.4677179499894422956.stgit@dwillia2-desk3.amr.corp.intel.com> <151520107001.32271.12149241186695668220.stgit@dwillia2-desk3.amr.corp.intel.com> <20180106090154.GE4380@kroah.com> Organization: Intel Corporation X-Mailer: Claws Mail 3.15.1-dirty (GTK+ 2.24.31; x86_64-redhat-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Return-Path: On Sat, 6 Jan 2018 10:01:54 +0100 Greg KH wrote: > On Fri, Jan 05, 2018 at 05:11:10PM -0800, Dan Williams wrote: > > Static analysis reports that 'offset' may be a user controlled value > > Can I see the rule that determined that? It does not feel like that is > correct, given the 3+ levels deep that this function gets this value > from... On a current x86 you can execute something upwards of 150 instructions in a speculation window. Alan