From nobody Wed Sep 3 06:26:07 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 8637EFA3746 for ; Mon, 24 Oct 2022 13:35:27 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235968AbiJXNeK (ORCPT ); Mon, 24 Oct 2022 09:34:10 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:42056 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S236190AbiJXN35 (ORCPT ); Mon, 24 Oct 2022 09:29:57 -0400 Received: from ams.source.kernel.org (ams.source.kernel.org [IPv6:2604:1380:4601:e00::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 3FF2EAC4AC; Mon, 24 Oct 2022 05:33:17 -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 ams.source.kernel.org (Postfix) with ESMTPS id 9F3F7B811C1; Mon, 24 Oct 2022 12:04:17 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id F145AC433D7; Mon, 24 Oct 2022 12:04:15 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1666613056; bh=QqpHLqiHJ8pQMZ2r9rm0Nz/ebpA/pgrtpSt7B2/lRsc=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=pcQjuQ/uDiZ+SmDlzrAHufTcvWDHFv/03JNe2rS6wMhbi6OhqSnxHV8DZp5K0/vNj Av9oj9WmjHb3VLmBvaHeBeuQvOOBOpRvpj+J3/yA8h+CQtF5YCRGfuUTtPQHjJL/4U ImPObQ8av9NTYmcyW3XECNmJSruO6ctoT3sCm3gQ= 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 4.19 191/229] Bluetooth: L2CAP: Fix user-after-free Date: Mon, 24 Oct 2022 13:31:50 +0200 Message-Id: <20221024113005.308616466@linuxfoundation.org> X-Mailer: git-send-email 2.38.1 In-Reply-To: <20221024112959.085534368@linuxfoundation.org> References: <20221024112959.085534368@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 7c280fcdcaa0..5c965f7b1709 100644 --- a/net/bluetooth/l2cap_core.c +++ b/net/bluetooth/l2cap_core.c @@ -4049,6 +4049,12 @@ 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); @@ -4078,6 +4084,7 @@ 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