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,URIBL_BLOCKED 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 6DF72C2F421 for ; Mon, 21 Jan 2019 14:48:42 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 3B1A62085A for ; Mon, 21 Jan 2019 14:48:42 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729546AbfAUOsg convert rfc822-to-8bit (ORCPT ); Mon, 21 Jan 2019 09:48:36 -0500 Received: from coyote.holtmann.net ([212.227.132.17]:33519 "EHLO mail.holtmann.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729072AbfAUOsg (ORCPT ); Mon, 21 Jan 2019 09:48:36 -0500 Received: from marcel-macpro.fritz.box (p4FF9FD60.dip0.t-ipconnect.de [79.249.253.96]) by mail.holtmann.org (Postfix) with ESMTPSA id 9B3D1CEE94; Mon, 21 Jan 2019 15:56:21 +0100 (CET) Content-Type: text/plain; charset=utf-8 Mime-Version: 1.0 (Mac OS X Mail 12.2 \(3445.102.3\)) Subject: Re: [PATCH] Bluetooth: hci_uart: Add a local variable to store the result of h4_recv_buf() From: Marcel Holtmann In-Reply-To: <20190120094459.GA22129@myunghoj-Precision-5530> Date: Mon, 21 Jan 2019 15:48:34 +0100 Cc: Johan Hedberg , linux-bluetooth@vger.kernel.org, linux-kernel@vger.kernel.org Content-Transfer-Encoding: 8BIT Message-Id: References: <20190111065514.GA26542@myunghoj-Precision-5530> <09FCB21A-2184-4CDB-8BF0-75C403DF39F9@holtmann.org> <20190119081919.GA10681@myunghoj-Precision-5530> <20190120094459.GA22129@myunghoj-Precision-5530> To: Myungho Jung X-Mailer: Apple Mail (2.3445.102.3) Sender: linux-bluetooth-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-bluetooth@vger.kernel.org Hi Myungho, >>>> In h4_recv(), if h4_recv_buf() returns error and h4_recv() is >>>> asynchronously called again before setting rx_skb to NULL, ERR_PTR will >>>> be dereferenced in h4_recv_buf(). Check return value in a local variable >>>> before writing to rx_skb. >>>> >>>> Reported-by: syzbot+017a32f149406df32703@syzkaller.appspotmail.com >>>> Signed-off-by: Myungho Jung >>>> --- >>>> drivers/bluetooth/hci_h4.c | 11 +++++++---- >>>> 1 file changed, 7 insertions(+), 4 deletions(-) >>> >>> patch has been applied to bluetooth-next tree. >>> >>> Can you actually fix all callers of h4_recv_buf since they all suffer from the same issue. >>> >>> Regards >>> >>> Marcel >>> >> >> Hi Marcel, >> >> Sure, let me check other callers and fix them if applicable. >> >> Thanks, >> Myungho >> > > Hi Marcel, > > I found there are many callers that need to be fixed. So, how about checking > error code in h4_recv_buf() instead? > > diff --git a/drivers/bluetooth/hci_h4.c b/drivers/bluetooth/hci_h4.c > index fb97a3bf069b..dea48090d2dc 100644 > --- a/drivers/bluetooth/hci_h4.c > +++ b/drivers/bluetooth/hci_h4.c > @@ -174,6 +174,10 @@ struct sk_buff *h4_recv_buf(struct hci_dev *hdev, struct sk_buff *skb, > struct hci_uart *hu = hci_get_drvdata(hdev); > u8 alignment = hu->alignment ? hu->alignment : 1; > > + /* Check if socket buffer is not reset yet from previous error */ > + if (IS_ERR(skb)) > + skb = NULL; > + > while (count) { > int i, len; > > > It is tested and verified by syzbot. The previous commit is no more needed if > this looks better. please send a proper patch for this and also don’t forget drivers/bluetooth/h4_recv.h since these two are not yet consolidated. Regards Marcel