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=-9.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,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 28BC1C433E2 for ; Sun, 30 Aug 2020 12:26:45 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 07E73214DB for ; Sun, 30 Aug 2020 12:26:45 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="Qn/++4J3" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728851AbgH3M0i (ORCPT ); Sun, 30 Aug 2020 08:26:38 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:58130 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728831AbgH3M0e (ORCPT ); Sun, 30 Aug 2020 08:26:34 -0400 Received: from mail-pl1-x644.google.com (mail-pl1-x644.google.com [IPv6:2607:f8b0:4864:20::644]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id D3F27C061573; Sun, 30 Aug 2020 05:26:33 -0700 (PDT) Received: by mail-pl1-x644.google.com with SMTP id x18so516404pll.6; Sun, 30 Aug 2020 05:26:33 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to; bh=ejqO87rorFkVXw0/ByXTM9CvLRvpm4qV9tVsBbkXl5I=; b=Qn/++4J3Z/bAbP0hfH0Wek8D4QXU9x5lXBOPjjGgyy3p6+DhkFdVlK0Qvg4sbZbHyi CspnA895diI0L0XAsK24N+J8fESh1feelF5xwmNNhoiSTCepBgdldjloZbw4/vZe2zDP MFGkygHfhqtWNHZh8kpm+fFqiz6gT1qfCwekkFSoTCejD0LBLfreK8URHXDxS9BRd0WL 9IGdmslXLCm0sIlbc6e9rhoSWtKYoR17FJ7W7FwGuRs1i7vfZoggNq+0lXyEQ8Z2FnOP cn26BnOtUttf/mNbMH2hNrvEXPEJ7hsA82rYu1pSJEvQ93ItrDGAR4UXt4O4uI5vEPnw Jt8Q== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to; bh=ejqO87rorFkVXw0/ByXTM9CvLRvpm4qV9tVsBbkXl5I=; b=FWs+QFB9pM+nZa4mQ7tSTToenNuVNBmjhnI+hu5JXsOK1rsa8Se9RfdU/SHMx44uGu oy9qwlkBbOn7CZurJzlnuA0K1CmGR4Ut6mJ5DqzkO0baRGihrg7OXjot85hMtJvc8Tpt MNGdg7WJsfML9RzLoqUxGPUf7S6eQMtv4EiPvxpSoM3tmxZRC9afCJC6rFvpdeR5VJ+B K4zjcMeJ2eERo/+XbU8iwGBTPfS9BLutrpMhXxkXr/gpL8MX1zTdVFbnJVTKgQ8lVOrc Tjy2Wk4ozADuk2NVn+VYwbxQzeWsamOG+eeStZ9Uy6xHuZnsY4Jl9ShW39L4cnGPg5p+ JR3Q== X-Gm-Message-State: AOAM533FdLyVa2aD9I6SVm7VunlDI5NM42XIiWaXoZI6H1Dr/G/cQabK paKTzjwSon55twUtr5PR1Yw= X-Google-Smtp-Source: ABdhPJzZtb1Nfg209xbdteCKN2XIoYQJIeLuvoBWNxezlKGZpJEy+OsTzIZvgQ8YxxVX/yrRKcwePw== X-Received: by 2002:a17:902:8347:: with SMTP id z7mr5506118pln.20.1598790391028; Sun, 30 Aug 2020 05:26:31 -0700 (PDT) Received: from Thinkpad ([45.118.165.143]) by smtp.gmail.com with ESMTPSA id lj3sm4290067pjb.26.2020.08.30.05.26.27 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sun, 30 Aug 2020 05:26:30 -0700 (PDT) Date: Sun, 30 Aug 2020 17:56:23 +0530 From: Anmol Karn To: Greg KH Cc: syzbot+0bef568258653cff272f@syzkaller.appspotmail.com, linux-kernel-mentees@lists.linuxfoundation.org, linux-kernel@vger.kernel.org, syzkaller-bugs@googlegroups.com, netdev@vger.kernel.org, linux-bluetooth@vger.kernel.org, kuba@kernel.org, davem@davemloft.net, anmol.karan123@gmail.com Subject: Re: [Linux-kernel-mentees] [PATCH] net: bluetooth: Fix null pointer deref in hci_phy_link_complete_evt Message-ID: <20200830122623.GA235919@Thinkpad> References: <20200829124112.227133-1-anmol.karan123@gmail.com> <20200829165712.229437-1-anmol.karan123@gmail.com> <20200830091917.GB122343@kroah.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200830091917.GB122343@kroah.com> Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org On Sun, Aug 30, 2020 at 11:19:17AM +0200, Greg KH wrote: > On Sat, Aug 29, 2020 at 10:27:12PM +0530, Anmol Karn wrote: > > Fix null pointer deref in hci_phy_link_complete_evt, there was no > > checking there for the hcon->amp_mgr->l2cap_conn->hconn, and also > > in hci_cmd_work, for hdev->sent_cmd. > > > > To fix this issue Add pointer checking in hci_cmd_work and > > hci_phy_link_complete_evt. > > [Linux-next-20200827] > > > > This patch corrected some mistakes from previous patch. > > > > Reported-by: syzbot+0bef568258653cff272f@syzkaller.appspotmail.com > > Link: https://syzkaller.appspot.com/bug?id=0d93140da5a82305a66a136af99b088b75177b99 > > Signed-off-by: Anmol Karn > > --- > > net/bluetooth/hci_core.c | 5 ++++- > > net/bluetooth/hci_event.c | 4 ++++ > > 2 files changed, 8 insertions(+), 1 deletion(-) > > > > diff --git a/net/bluetooth/hci_core.c b/net/bluetooth/hci_core.c > > index 68bfe57b6625..996efd654e7a 100644 > > --- a/net/bluetooth/hci_core.c > > +++ b/net/bluetooth/hci_core.c > > @@ -4922,7 +4922,10 @@ static void hci_cmd_work(struct work_struct *work) > > > > kfree_skb(hdev->sent_cmd); > > > > - hdev->sent_cmd = skb_clone(skb, GFP_KERNEL); > > + if (hdev->sent_cmd) { > > + hdev->sent_cmd = skb_clone(skb, GFP_KERNEL); > > + } > > How can sent_cmd be NULL here? Are you sure something previous to this > shouldn't be fixed instead? Sir, sent_cmd was freed before this condition check, thats why i checked it, i think i should check it before the free of hdev->sent_cmd like, if (hdev->sent_cmd) kfree_skb(hdev->sent_cmd); what's your opininon on this. > > > > + > > if (hdev->sent_cmd) { > > if (hci_req_status_pend(hdev)) > > hci_dev_set_flag(hdev, HCI_CMD_PENDING); > > diff --git a/net/bluetooth/hci_event.c b/net/bluetooth/hci_event.c > > index 4b7fc430793c..1e7d9bee9111 100644 > > --- a/net/bluetooth/hci_event.c > > +++ b/net/bluetooth/hci_event.c > > @@ -4941,6 +4941,10 @@ static void hci_phy_link_complete_evt(struct hci_dev *hdev, > > hci_dev_unlock(hdev); > > return; > > } > > + if (!(hcon->amp_mgr->l2cap_conn->hcon)) { > > + hci_dev_unlock(hdev); > > + return; > > + } > > How can this be triggered? syzbot showed that this line is accessed irrespective of the null value it contains, so added a pointer check for that. please give some opinions on this, if (!bredr_hcon) { hci_dev_unlock(hdev); return; } Thanks, Anmol Karn