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=-12.8 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,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 A210CC5DF9E for ; Tue, 27 Oct 2020 14:30:43 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 6D2EA2225E for ; Tue, 27 Oct 2020 14:30:43 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1603809043; bh=XIuKh7y6g3fy9U1Dl3xFHCmsboBF0LOcOxQ/tlpaPtI=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=s7J4aLypHzSIKXYWQHeODlyyD12a4RbrHhNBdjQAE8l0B06WT6Zj2Q5id3i/UBffB qSxPRp+74j5TamW0bu8W5ifFst4+0Ca+Ju4SPCDSZkqUZgs487f13vQjFE5lN3L2Bj 9fP3vLWpU472aPIr7zYj+1C1+074bUW2m5z0GYcU= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1759163AbgJ0O2H (ORCPT ); Tue, 27 Oct 2020 10:28:07 -0400 Received: from mail.kernel.org ([198.145.29.99]:54392 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1759154AbgJ0O2G (ORCPT ); Tue, 27 Oct 2020 10:28:06 -0400 Received: from localhost (83-86-74-64.cable.dynamic.v4.ziggo.nl [83.86.74.64]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id D4D8E20780; Tue, 27 Oct 2020 14:28:05 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1603808886; bh=XIuKh7y6g3fy9U1Dl3xFHCmsboBF0LOcOxQ/tlpaPtI=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=Zq6gCkR1NrA4DAZ2JEr69gHjrNUMljSH+2NP9ddpcc8Jhv5PITqaQ+5QJziCvRyRT 2iVgh3Mo6eWniLNxHf05gTfGOrE3YtRWW9W1F/2c4le4S2OnSlrl7V9LPC3JT8YSc+ DziVPv5kUL2i0XJkQhKsuolY+RGIHXaSh2XV9GB8= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Abhishek Pandit-Subedi , Balakrishna Godavarthi , Manish Mandlik , Marcel Holtmann , Sasha Levin Subject: [PATCH 4.19 244/264] Bluetooth: Only mark socket zapped after unlocking Date: Tue, 27 Oct 2020 14:55:02 +0100 Message-Id: <20201027135442.122528160@linuxfoundation.org> X-Mailer: git-send-email 2.29.1 In-Reply-To: <20201027135430.632029009@linuxfoundation.org> References: <20201027135430.632029009@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: stable@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 2a85dc3be8bf3..198a1fdd6709e 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