From nobody Fri Dec 19 06:07:44 2025 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 6B605FA373E for ; Mon, 24 Oct 2022 12:21:59 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233446AbiJXMV5 (ORCPT ); Mon, 24 Oct 2022 08:21:57 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:38444 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233541AbiJXMTq (ORCPT ); Mon, 24 Oct 2022 08:19:46 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id DB40F753B9; Mon, 24 Oct 2022 04:58:34 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id A71A461278; Mon, 24 Oct 2022 11:44:12 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id B6F60C433D6; Mon, 24 Oct 2022 11:44:11 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1666611852; bh=5Iqm60SwyyyRfJTCk22dEZia1Xh8h760FMFhJi50/Ik=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=IBbSC5Rv6funo+s+4ddbfw5c8SixcdkAs8OtTpaVZpQqaNWxdqIKkk4hHzvu0BLxL znLS0VBPeQiKOk7UhGgbOSw6zh0eoNcs+/p2WiRieJgCQvbP1j7lf7J56LnFhl78Wb tzrenB2p7VW6shm9RveEwP0h9Q2sce4rvdz2MM9o= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Luiz Augusto von Dentz , Sungwoo Kim , Sasha Levin Subject: [PATCH 4.9 135/159] Bluetooth: L2CAP: Fix user-after-free Date: Mon, 24 Oct 2022 13:31:29 +0200 Message-Id: <20221024112954.396342352@linuxfoundation.org> X-Mailer: git-send-email 2.38.1 In-Reply-To: <20221024112949.358278806@linuxfoundation.org> References: <20221024112949.358278806@linuxfoundation.org> User-Agent: quilt/0.67 MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" From: Luiz Augusto von Dentz [ Upstream commit 35fcbc4243aad7e7d020b7c1dfb14bb888b20a4f ] This uses l2cap_chan_hold_unless_zero() after calling __l2cap_get_chan_blah() to prevent the following trace: Bluetooth: l2cap_core.c:static void l2cap_chan_destroy(struct kref *kref) Bluetooth: chan 0000000023c4974d Bluetooth: parent 00000000ae861c08 =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D BUG: KASAN: use-after-free in __mutex_waiter_is_first kernel/locking/mutex.c:191 [inline] BUG: KASAN: use-after-free in __mutex_lock_common kernel/locking/mutex.c:671 [inline] BUG: KASAN: use-after-free in __mutex_lock+0x278/0x400 kernel/locking/mutex.c:729 Read of size 8 at addr ffff888006a49b08 by task kworker/u3:2/389 Link: https://lore.kernel.org/lkml/20220622082716.478486-1-lee.jones@linaro= .org Signed-off-by: Luiz Augusto von Dentz Signed-off-by: Sungwoo Kim Signed-off-by: Sasha Levin --- net/bluetooth/l2cap_core.c | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/net/bluetooth/l2cap_core.c b/net/bluetooth/l2cap_core.c index 42df17fa7f16..ec04a7ea5537 100644 --- a/net/bluetooth/l2cap_core.c +++ b/net/bluetooth/l2cap_core.c @@ -4039,6 +4039,12 @@ static int l2cap_connect_create_rsp(struct l2cap_con= n *conn, } } =20 + chan =3D l2cap_chan_hold_unless_zero(chan); + if (!chan) { + err =3D -EBADSLT; + goto unlock; + } + err =3D 0; =20 l2cap_chan_lock(chan); @@ -4068,6 +4074,7 @@ static int l2cap_connect_create_rsp(struct l2cap_conn= *conn, } =20 l2cap_chan_unlock(chan); + l2cap_chan_put(chan); =20 unlock: mutex_unlock(&conn->chan_lock); --=20 2.35.1