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=-13.1 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT 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 4305AC433E7 for ; Sun, 18 Oct 2020 19:38:20 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 1858922267 for ; Sun, 18 Oct 2020 19:38:20 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1603049900; bh=HDCMGJf1kIhpPN93Q61Pxo3Rl/dSL5wdEcz8+ka9Cs8=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=sZDN0puMYKH0nKDJzC2brt0TIMAb45mRzDkTKqiadKjvcX8AKdPDFGldG0hLCkjHM wZGmPGil6NQvAeaCCzOVK/xq+xDeHXOSzutQyNNL0Dd2fToJ4k5l/vBFwBVeHMitRC UuQ4W16w/s6sXQuEO6y5v6wVZD/xyki3OrSbBSsM= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1732874AbgJRTiQ (ORCPT ); Sun, 18 Oct 2020 15:38:16 -0400 Received: from mail.kernel.org ([198.145.29.99]:39424 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1731160AbgJRTZI (ORCPT ); Sun, 18 Oct 2020 15:25:08 -0400 Received: from sasha-vm.mshome.net (c-73-47-72-35.hsd1.nh.comcast.net [73.47.72.35]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 9ACFB222C8; Sun, 18 Oct 2020 19:25:06 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1603049107; bh=HDCMGJf1kIhpPN93Q61Pxo3Rl/dSL5wdEcz8+ka9Cs8=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=TivyR0MCKlLVV/ttghSQDIf1PWjE61FQ0CbxV+d4hMX0M/KmA65/cRqyJ6axS5o5X wrbHZOds14DmC5ZPi/nGLfpNCctiyBu/vl5TdqpoaoUIjrhNh9NYCsMo701Bij4EUf kLhsM0i1EC/KEcZtTnb75ZgF3adkh4KemFG0HMsY= From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Abhishek Pandit-Subedi , Balakrishna Godavarthi , Manish Mandlik , Marcel Holtmann , Sasha Levin , linux-bluetooth@vger.kernel.org, netdev@vger.kernel.org Subject: [PATCH AUTOSEL 4.19 41/56] Bluetooth: Only mark socket zapped after unlocking Date: Sun, 18 Oct 2020 15:24:02 -0400 Message-Id: <20201018192417.4055228-41-sashal@kernel.org> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20201018192417.4055228-1-sashal@kernel.org> References: <20201018192417.4055228-1-sashal@kernel.org> MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org From: Abhishek Pandit-Subedi [ Upstream commit 20ae4089d0afeb24e9ceb026b996bfa55c983cc2 ] Since l2cap_sock_teardown_cb doesn't acquire the channel lock before setting the socket as zapped, it could potentially race with l2cap_sock_release which frees the socket. Thus, wait until the cleanup is complete before marking the socket as zapped. This race was reproduced on a JBL GO speaker after the remote device rejected L2CAP connection due to resource unavailability. Here is a dmesg log with debug logs from a repro of this bug: [ 3465.424086] Bluetooth: hci_core.c:hci_acldata_packet() hci0 len 16 handle 0x0003 flags 0x0002 [ 3465.424090] Bluetooth: hci_conn.c:hci_conn_enter_active_mode() hcon 00000000cfedd07d mode 0 [ 3465.424094] Bluetooth: l2cap_core.c:l2cap_recv_acldata() conn 000000007eae8952 len 16 flags 0x2 [ 3465.424098] Bluetooth: l2cap_core.c:l2cap_recv_frame() len 12, cid 0x0001 [ 3465.424102] Bluetooth: l2cap_core.c:l2cap_raw_recv() conn 000000007eae8952 [ 3465.424175] Bluetooth: l2cap_core.c:l2cap_sig_channel() code 0x03 len 8 id 0x0c [ 3465.424180] Bluetooth: l2cap_core.c:l2cap_connect_create_rsp() dcid 0x0045 scid 0x0000 result 0x02 status 0x00 [ 3465.424189] Bluetooth: l2cap_core.c:l2cap_chan_put() chan 000000006acf9bff orig refcnt 4 [ 3465.424196] Bluetooth: l2cap_core.c:l2cap_chan_del() chan 000000006acf9bff, conn 000000007eae8952, err 111, state BT_CONNECT [ 3465.424203] Bluetooth: l2cap_sock.c:l2cap_sock_teardown_cb() chan 000000006acf9bff state BT_CONNECT [ 3465.424221] Bluetooth: l2cap_core.c:l2cap_chan_put() chan 000000006acf9bff orig refcnt 3 [ 3465.424226] Bluetooth: hci_core.h:hci_conn_drop() hcon 00000000cfedd07d orig refcnt 6 [ 3465.424234] BUG: spinlock bad magic on CPU#2, kworker/u17:0/159 [ 3465.425626] Bluetooth: hci_sock.c:hci_sock_sendmsg() sock 000000002bb0cb64 sk 00000000a7964053 [ 3465.430330] lock: 0xffffff804410aac0, .magic: 00000000, .owner: /-1, .owner_cpu: 0 [ 3465.430332] Causing a watchdog bite! Signed-off-by: Abhishek Pandit-Subedi Reported-by: Balakrishna Godavarthi Reviewed-by: Manish Mandlik Signed-off-by: Marcel Holtmann Signed-off-by: Sasha Levin --- net/bluetooth/l2cap_sock.c | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-) diff --git a/net/bluetooth/l2cap_sock.c b/net/bluetooth/l2cap_sock.c index 5572042f04531..eb979532a3839 100644 --- a/net/bluetooth/l2cap_sock.c +++ b/net/bluetooth/l2cap_sock.c @@ -1341,8 +1341,6 @@ static void l2cap_sock_teardown_cb(struct l2cap_chan *chan, int err) parent = bt_sk(sk)->parent; - sock_set_flag(sk, SOCK_ZAPPED); - switch (chan->state) { case BT_OPEN: case BT_BOUND: @@ -1369,8 +1367,11 @@ static void l2cap_sock_teardown_cb(struct l2cap_chan *chan, int err) break; } - release_sock(sk); + + /* Only zap after cleanup to avoid use after free race */ + sock_set_flag(sk, SOCK_ZAPPED); + } static void l2cap_sock_state_change_cb(struct l2cap_chan *chan, int state, -- 2.25.1