From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-7.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id F0DF0C43381 for ; Sat, 2 Mar 2019 16:46:56 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id C3F9F20838 for ; Sat, 2 Mar 2019 16:46:56 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726674AbfCBQqw convert rfc822-to-8bit (ORCPT ); Sat, 2 Mar 2019 11:46:52 -0500 Received: from coyote.holtmann.net ([212.227.132.17]:53489 "EHLO mail.holtmann.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726282AbfCBQqv (ORCPT ); Sat, 2 Mar 2019 11:46:51 -0500 Received: from marcel-macpro.fritz.box (p4FF9F361.dip0.t-ipconnect.de [79.249.243.97]) by mail.holtmann.org (Postfix) with ESMTPSA id 48389CF352; Sat, 2 Mar 2019 17:54:46 +0100 (CET) Content-Type: text/plain; charset=us-ascii Mime-Version: 1.0 (Mac OS X Mail 12.2 \(3445.102.3\)) Subject: Re: [PATCH] net/bluetooth: Fix bound check in event handling From: Marcel Holtmann In-Reply-To: <20190228195939.30685-1-tomasbortoli@gmail.com> Date: Sat, 2 Mar 2019 17:46:49 +0100 Cc: Johan Hedberg , "David S. Miller" , "open list:BLUETOOTH DRIVERS" , netdev@vger.kernel.org, linux-kernel@vger.kernel.org, syzkaller@googlegroups.com Content-Transfer-Encoding: 8BIT Message-Id: <8F6AC5BF-F50B-4C30-A73B-98526AF181EB@holtmann.org> References: <20190228195939.30685-1-tomasbortoli@gmail.com> To: Tomas Bortoli X-Mailer: Apple Mail (2.3445.102.3) Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org Hi Tomas, > hci_inquiry_result_with_rssi_evt() can perform out of bound reads > on skb->data as a bound check is missing. > > Signed-off-by: Tomas Bortoli > Reported-by: syzbot+cec7a50c412a2c03f8f5@syzkaller.appspotmail.com > Reported-by: syzbot+660883c56e2fa65d4497@syzkaller.appspotmail.com > --- > Syzkaler reports: > https://syzkaller.appspot.com/bug?id=d708485af9edc3af35f3b4d554e827c6c8bf6b0f > https://syzkaller.appspot.com/bug?id=3acd1155d48a5acc5d76711568b04926945a6885 > > net/bluetooth/hci_event.c | 4 ++++ > 1 file changed, 4 insertions(+) > > diff --git a/net/bluetooth/hci_event.c b/net/bluetooth/hci_event.c > index ac2826ce162b..aa953d23bb72 100644 > --- a/net/bluetooth/hci_event.c > +++ b/net/bluetooth/hci_event.c > @@ -3983,6 +3983,10 @@ static void hci_inquiry_result_with_rssi_evt(struct hci_dev *hdev, > for (; num_rsp; num_rsp--, info++) { > u32 flags; > > + if ((void *)(info + sizeof(info)) > > + (void *)(skb->data + skb->len)) > + break; > + first of all, the loop exists twice here. If one is vulnerable, then the second is a well. And second, can we not just do this inside the for-condition check or a lot simpler than this void casting fun. Regards Marcel