From mboxrd@z Thu Jan 1 00:00:00 1970 From: Stefano Brivio Subject: Re: [PATCH v2] i40e/i40evf: fix out-of-bounds read of cpumask Date: Tue, 22 Aug 2017 23:23:49 +0200 Message-ID: <20170822232349.52b9ad06@elisabeth> References: <20170822210442.18006-1-jacob.e.keller@intel.com> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Cc: Intel Wired LAN , netdev@vger.kernel.org, stable@vger.kernel.org, Juergen Gross To: Jacob Keller Return-path: Received: from mx1.redhat.com ([209.132.183.28]:63492 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751853AbdHVVX6 (ORCPT ); Tue, 22 Aug 2017 17:23:58 -0400 In-Reply-To: <20170822210442.18006-1-jacob.e.keller@intel.com> Sender: netdev-owner@vger.kernel.org List-ID: [Fixed Cc: address for stable, Cc'ed Juergen] On Tue, 22 Aug 2017 14:04:42 -0700 Jacob Keller wrote: > When responding to an affinity hint we directly copied a cpumask value, > intsead of using cpumask_copy. According to cpumask.h this is not > correct because cpumask_t is only guaranteed to have enough space for > the number of CPUs in the system, and may not be as big as we expect. > Thus a direct copy results in an out-of-bound read and potentially > a crash if the pages are aligned just right. This will be easily > detected on a kernel with KASAN enabled: I still think commit message of my patch (ae9c9586f61e914dc1c6fe2e6ac1fb2bf07283bc.1502792828.git.sbrivio@redhat.com) was perhaps a bit clearer, but okay, this is also clear, fair enough. > KASAN reports: > [ 25.242312] BUG: KASAN: slab-out-of-bounds in i40e_irq_affinity_notify+0x30/0x50 [i40e] at addr ffff880462eea960 [...] > [ 25.242597] ================================================================== This is also taken from my message, not terribly happy about it (and still happier with it than without). Fair enough, whatever it takes to get this applied as soon as possible... > Fixes: 96db776a3682 ("i40e/i40evf: fix interrupt affinity bug", 2016-09-14) > Signed-off-by: Jacob Keller > Cc: stable@vger.kernel.org # 4.10+ FWIW, Acked-by: Stefano Brivio