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,USER_AGENT_GIT autolearn=ham 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 1767DC433E1 for ; Mon, 17 Aug 2020 19:45:44 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id E0CDA20855 for ; Mon, 17 Aug 2020 19:45:43 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1597693543; bh=wNpQYJFvzAHC3btzCqiA6w25nsGp1ZuOBw4d9rOui6k=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=2sl1Tkap6LFDzqA8yXw11Yq0QDVvvFqJJCOzgYEE+EKJhG1D6Ny7z95vcnxkrqmgb hQdK7FVNAXR/1W97VImbnX8cK818PtU6A2bn5ZjwA25uVNVPsDA4O5DjMnklav6yVM oOvsCLxS1dPk42IfzHIgnYFmdH1aer7tDIroVJ2k= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2404368AbgHQTpl (ORCPT ); Mon, 17 Aug 2020 15:45:41 -0400 Received: from mail.kernel.org ([198.145.29.99]:44978 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729341AbgHQPV5 (ORCPT ); Mon, 17 Aug 2020 11:21:57 -0400 Received: from localhost (83-86-89-107.cable.dynamic.v4.ziggo.nl [83.86.89.107]) (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 EFA9222D07; Mon, 17 Aug 2020 15:21:55 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1597677716; bh=wNpQYJFvzAHC3btzCqiA6w25nsGp1ZuOBw4d9rOui6k=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=nIblKl/g4U/pQViUtorHAlX6eopfBcRhEQoMhjpQQ7aZtSeHtI/fe8UdxnNelGMrp VVmDeFiy9eeddgJwdQyEw94AOXV9ssbEPjAeP1shsubLkftgBEeV30SMqs2wJMZCtr 4j+qU+gW8XULJsRGUow3SIFD4OURYj7CkULjc8Pk= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, syzbot+96414aa0033c363d8458@syzkaller.appspotmail.com, Lihong Kou , Marcel Holtmann , Sasha Levin Subject: [PATCH 5.8 081/464] Bluetooth: add a mutex lock to avoid UAF in do_enale_set Date: Mon, 17 Aug 2020 17:10:34 +0200 Message-Id: <20200817143837.661655849@linuxfoundation.org> X-Mailer: git-send-email 2.28.0 In-Reply-To: <20200817143833.737102804@linuxfoundation.org> References: <20200817143833.737102804@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Lihong Kou [ Upstream commit f9c70bdc279b191da8d60777c627702c06e4a37d ] In the case we set or free the global value listen_chan in different threads, we can encounter the UAF problems because the method is not protected by any lock, add one to avoid this bug. BUG: KASAN: use-after-free in l2cap_chan_close+0x48/0x990 net/bluetooth/l2cap_core.c:730 Read of size 8 at addr ffff888096950000 by task kworker/1:102/2868 CPU: 1 PID: 2868 Comm: kworker/1:102 Not tainted 5.5.0-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Workqueue: events do_enable_set Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x1fb/0x318 lib/dump_stack.c:118 print_address_description+0x74/0x5c0 mm/kasan/report.c:374 __kasan_report+0x149/0x1c0 mm/kasan/report.c:506 kasan_report+0x26/0x50 mm/kasan/common.c:641 __asan_report_load8_noabort+0x14/0x20 mm/kasan/generic_report.c:135 l2cap_chan_close+0x48/0x990 net/bluetooth/l2cap_core.c:730 do_enable_set+0x660/0x900 net/bluetooth/6lowpan.c:1074 process_one_work+0x7f5/0x10f0 kernel/workqueue.c:2264 worker_thread+0xbbc/0x1630 kernel/workqueue.c:2410 kthread+0x332/0x350 kernel/kthread.c:255 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352 Allocated by task 2870: save_stack mm/kasan/common.c:72 [inline] set_track mm/kasan/common.c:80 [inline] __kasan_kmalloc+0x118/0x1c0 mm/kasan/common.c:515 kasan_kmalloc+0x9/0x10 mm/kasan/common.c:529 kmem_cache_alloc_trace+0x221/0x2f0 mm/slab.c:3551 kmalloc include/linux/slab.h:555 [inline] kzalloc include/linux/slab.h:669 [inline] l2cap_chan_create+0x50/0x320 net/bluetooth/l2cap_core.c:446 chan_create net/bluetooth/6lowpan.c:640 [inline] bt_6lowpan_listen net/bluetooth/6lowpan.c:959 [inline] do_enable_set+0x6a4/0x900 net/bluetooth/6lowpan.c:1078 process_one_work+0x7f5/0x10f0 kernel/workqueue.c:2264 worker_thread+0xbbc/0x1630 kernel/workqueue.c:2410 kthread+0x332/0x350 kernel/kthread.c:255 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352 Freed by task 2870: save_stack mm/kasan/common.c:72 [inline] set_track mm/kasan/common.c:80 [inline] kasan_set_free_info mm/kasan/common.c:337 [inline] __kasan_slab_free+0x12e/0x1e0 mm/kasan/common.c:476 kasan_slab_free+0xe/0x10 mm/kasan/common.c:485 __cache_free mm/slab.c:3426 [inline] kfree+0x10d/0x220 mm/slab.c:3757 l2cap_chan_destroy net/bluetooth/l2cap_core.c:484 [inline] kref_put include/linux/kref.h:65 [inline] l2cap_chan_put+0x170/0x190 net/bluetooth/l2cap_core.c:498 do_enable_set+0x66c/0x900 net/bluetooth/6lowpan.c:1075 process_one_work+0x7f5/0x10f0 kernel/workqueue.c:2264 worker_thread+0xbbc/0x1630 kernel/workqueue.c:2410 kthread+0x332/0x350 kernel/kthread.c:255 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352 The buggy address belongs to the object at ffff888096950000 which belongs to the cache kmalloc-2k of size 2048 The buggy address is located 0 bytes inside of 2048-byte region [ffff888096950000, ffff888096950800) The buggy address belongs to the page: page:ffffea00025a5400 refcount:1 mapcount:0 mapping:ffff8880aa400e00 index:0x0 flags: 0xfffe0000000200(slab) raw: 00fffe0000000200 ffffea00027d1548 ffffea0002397808 ffff8880aa400e00 raw: 0000000000000000 ffff888096950000 0000000100000001 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff88809694ff00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ffff88809694ff80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 >ffff888096950000: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff888096950080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff888096950100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ================================================================== Reported-by: syzbot+96414aa0033c363d8458@syzkaller.appspotmail.com Signed-off-by: Lihong Kou Signed-off-by: Marcel Holtmann Signed-off-by: Sasha Levin --- net/bluetooth/6lowpan.c | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/net/bluetooth/6lowpan.c b/net/bluetooth/6lowpan.c index bb55d92691b06..cff4944d5b663 100644 --- a/net/bluetooth/6lowpan.c +++ b/net/bluetooth/6lowpan.c @@ -50,6 +50,7 @@ static bool enable_6lowpan; /* We are listening incoming connections via this channel */ static struct l2cap_chan *listen_chan; +static DEFINE_MUTEX(set_lock); struct lowpan_peer { struct list_head list; @@ -1078,12 +1079,14 @@ static void do_enable_set(struct work_struct *work) enable_6lowpan = set_enable->flag; + mutex_lock(&set_lock); if (listen_chan) { l2cap_chan_close(listen_chan, 0); l2cap_chan_put(listen_chan); } listen_chan = bt_6lowpan_listen(); + mutex_unlock(&set_lock); kfree(set_enable); } @@ -1135,11 +1138,13 @@ static ssize_t lowpan_control_write(struct file *fp, if (ret == -EINVAL) return ret; + mutex_lock(&set_lock); if (listen_chan) { l2cap_chan_close(listen_chan, 0); l2cap_chan_put(listen_chan); listen_chan = NULL; } + mutex_unlock(&set_lock); if (conn) { struct lowpan_peer *peer; -- 2.25.1