From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751516AbeA2RB1 (ORCPT ); Mon, 29 Jan 2018 12:01:27 -0500 Received: from shards.monkeyblade.net ([184.105.139.130]:45420 "EHLO shards.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750959AbeA2RB0 (ORCPT ); Mon, 29 Jan 2018 12:01:26 -0500 Date: Mon, 29 Jan 2018 12:01:24 -0500 (EST) Message-Id: <20180129.120124.892750865825553841.davem@davemloft.net> To: jasowang@redhat.com Cc: mst@redhat.com, linux-kernel@vger.kernel.org, netdev@vger.kernel.org, john.fastabend@gmail.com Subject: Re: [PATCH net-next] ptr_ring: fix integer overflow From: David Miller In-Reply-To: <1516865502-20835-1-git-send-email-jasowang@redhat.com> References: <1516865502-20835-1-git-send-email-jasowang@redhat.com> X-Mailer: Mew version 6.7 on Emacs 25.3 / Mule 6.0 (HANACHIRUSATO) 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 From: Jason Wang Date: Thu, 25 Jan 2018 15:31:42 +0800 > We try to allocate one more entry for lockless peeking. The adding > operation may overflow which causes zero to be passed to kmalloc(). > In this case, it returns ZERO_SIZE_PTR without any notice by ptr > ring. Try to do producing or consuming on such ring will lead NULL > dereference. Fix this detect and fail early. > > Fixes: bcecb4bbf88a ("net: ptr_ring: otherwise safe empty checks can overrun array bounds") > Reported-by: syzbot+87678bcf753b44c39b67@syzkaller.appspotmail.com > Cc: John Fastabend > Signed-off-by: Jason Wang I'm dropping this because I am to understand that Michael Tsirkin's patch series covers this issue. Let me know if I still need to apply this. Thanks.