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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 530B3C38A2D for ; Mon, 24 Oct 2022 12:58:35 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232143AbiJXM6c (ORCPT ); Mon, 24 Oct 2022 08:58:32 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:54140 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234834AbiJXM5k (ORCPT ); Mon, 24 Oct 2022 08:57:40 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id ACA8397D63; Mon, 24 Oct 2022 05:16:57 -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 9D4C66131A; Mon, 24 Oct 2022 12:13:47 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id AF092C433D6; Mon, 24 Oct 2022 12:13:46 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1666613627; bh=maJ8fNNyCcC99rqyWAvsYKYOT4uvsH7Am3h5FOC+4NU=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=Z3U3kpmaW/P/JB1ExNpfCjsy4CZ9RZWRgrqW7GpWjABOvmIigqiinl7jwSMV46qc5 onA8/F0hN5six1PGWLR4I6Oau5BV9jh7KHyOwVjv4CKQk3XGZWcPCtyEIosPAucgdl MCAmO5eM1WHQvnLAW9BZbe53+8EJ7Pdimm6QQ2r0= 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 5.4 208/255] Bluetooth: L2CAP: Fix user-after-free Date: Mon, 24 Oct 2022 13:31:58 +0200 Message-Id: <20221024113009.958321735@linuxfoundation.org> X-Mailer: git-send-email 2.38.1 In-Reply-To: <20221024113002.471093005@linuxfoundation.org> References: <20221024113002.471093005@linuxfoundation.org> User-Agent: quilt/0.67 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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 ================================================================== 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 442432f89be1..2d28b4e49b7a 100644 --- a/net/bluetooth/l2cap_core.c +++ b/net/bluetooth/l2cap_core.c @@ -4066,6 +4066,12 @@ static int l2cap_connect_create_rsp(struct l2cap_conn *conn, } } + chan = l2cap_chan_hold_unless_zero(chan); + if (!chan) { + err = -EBADSLT; + goto unlock; + } + err = 0; l2cap_chan_lock(chan); @@ -4095,6 +4101,7 @@ static int l2cap_connect_create_rsp(struct l2cap_conn *conn, } l2cap_chan_unlock(chan); + l2cap_chan_put(chan); unlock: mutex_unlock(&conn->chan_lock); -- 2.35.1