From patchwork Mon Oct 9 12:30:45 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Ziyang Xuan (William)" X-Patchwork-Id: 13413667 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 39CB9E95A91 for ; Mon, 9 Oct 2023 12:32:40 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1346571AbjJIMcj (ORCPT ); Mon, 9 Oct 2023 08:32:39 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:58862 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1346645AbjJIMcZ (ORCPT ); Mon, 9 Oct 2023 08:32:25 -0400 Received: from szxga01-in.huawei.com (szxga01-in.huawei.com [45.249.212.187]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 219182683 for ; Mon, 9 Oct 2023 05:30:52 -0700 (PDT) Received: from canpemm500006.china.huawei.com (unknown [172.30.72.54]) by szxga01-in.huawei.com (SkyGuard) with ESMTP id 4S3ytv2cmkztTNJ; Mon, 9 Oct 2023 20:26:15 +0800 (CST) Received: from localhost.localdomain (10.175.104.82) by canpemm500006.china.huawei.com (7.192.105.130) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2507.31; Mon, 9 Oct 2023 20:30:50 +0800 From: Ziyang Xuan To: , , , Subject: [PATCH v2] Bluetooth: Fix UAF for hci_chan Date: Mon, 9 Oct 2023 20:30:45 +0800 Message-ID: <20231009123045.587882-1-william.xuanziyang@huawei.com> X-Mailer: git-send-email 2.25.1 MIME-Version: 1.0 X-Originating-IP: [10.175.104.82] X-ClientProxiedBy: dggems703-chm.china.huawei.com (10.3.19.180) To canpemm500006.china.huawei.com (7.192.105.130) X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: linux-bluetooth@vger.kernel.org Syzbot reports a UAF problem as follows: BUG: KASAN: slab-use-after-free in hci_send_acl+0x48/0xe70 net/bluetooth/hci_core.c:3231 ... Call Trace: __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0x1e7/0x2d0 lib/dump_stack.c:106 print_address_description mm/kasan/report.c:364 [inline] print_report+0x163/0x540 mm/kasan/report.c:475 kasan_report+0x175/0x1b0 mm/kasan/report.c:588 hci_send_acl+0x48/0xe70 net/bluetooth/hci_core.c:3231 l2cap_send_conn_req net/bluetooth/l2cap_core.c:1286 [inline] l2cap_start_connection+0x465/0x620 net/bluetooth/l2cap_core.c:1514 l2cap_conn_start+0xbf3/0x1130 net/bluetooth/l2cap_core.c:1661 process_one_work kernel/workqueue.c:2630 [inline] process_scheduled_works+0x90f/0x1400 kernel/workqueue.c:2703 worker_thread+0xa5f/0xff0 kernel/workqueue.c:2784 kthread+0x2d3/0x370 kernel/kthread.c:388 ret_from_fork+0x48/0x80 arch/x86/kernel/process.c:147 ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:304 Allocated by task 27110: kasan_save_stack mm/kasan/common.c:45 [inline] kasan_set_track+0x4f/0x70 mm/kasan/common.c:52 ____kasan_kmalloc mm/kasan/common.c:374 [inline] __kasan_kmalloc+0x98/0xb0 mm/kasan/common.c:383 kmalloc include/linux/slab.h:599 [inline] kzalloc include/linux/slab.h:720 [inline] hci_chan_create+0xc8/0x300 net/bluetooth/hci_conn.c:2714 l2cap_conn_add+0x69/0xc10 net/bluetooth/l2cap_core.c:7841 l2cap_chan_connect+0x61f/0xeb0 net/bluetooth/l2cap_core.c:8053 bt_6lowpan_connect net/bluetooth/6lowpan.c:894 [inline] lowpan_control_write+0x55e/0x850 net/bluetooth/6lowpan.c:1129 full_proxy_write+0x113/0x1c0 fs/debugfs/file.c:236 vfs_write+0x286/0xaf0 fs/read_write.c:582 ksys_write+0x1a0/0x2c0 fs/read_write.c:637 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x41/0xc0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x63/0xcd Freed by task 5067: kasan_save_stack mm/kasan/common.c:45 [inline] kasan_set_track+0x4f/0x70 mm/kasan/common.c:52 kasan_save_free_info+0x28/0x40 mm/kasan/generic.c:522 ____kasan_slab_free+0xd6/0x120 mm/kasan/common.c:236 kasan_slab_free include/linux/kasan.h:164 [inline] slab_free_hook mm/slub.c:1800 [inline] slab_free_freelist_hook mm/slub.c:1826 [inline] slab_free mm/slub.c:3809 [inline] __kmem_cache_free+0x25f/0x3b0 mm/slub.c:3822 hci_chan_list_flush net/bluetooth/hci_conn.c:2754 [inline] hci_conn_cleanup net/bluetooth/hci_conn.c:152 [inline] hci_conn_del+0x4f8/0xc40 net/bluetooth/hci_conn.c:1156 hci_abort_conn_sync+0xa45/0xfe0 hci_cmd_sync_work+0x228/0x400 net/bluetooth/hci_sync.c:306 process_one_work kernel/workqueue.c:2630 [inline] process_scheduled_works+0x90f/0x1400 kernel/workqueue.c:2703 worker_thread+0xa5f/0xff0 kernel/workqueue.c:2784 kthread+0x2d3/0x370 kernel/kthread.c:388 ret_from_fork+0x48/0x80 arch/x86/kernel/process.c:147 ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:304 There are two main reasons for this: 1. In the case of hci_conn_add() concurrency, the handle of hci_conn allocated through hci_conn_hash_alloc_unset() is not unique. That will result in getting the wrong hci_conn by hci_conn_hash_lookup_handle(). 2. The processes related to hci_abort_conn() can re-enter for the same hci_conn because atomic_dec_and_test(&hci_conn->refcnt) is established in hci_conn_drop(). That will make hci_conn UAF. To fix this, use ida to manage the allocation of conn->handle, and add the HCI_CONN_DISC flag to avoid re-entering of the processes related to hci_abort_conn(). Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Signed-off-by: Ziyang Xuan --- v2: - Rebase patch base on newest repo. - Remove HCI_CONN_DISC check in lookup interfaces. --- include/net/bluetooth/hci_core.h | 6 ++++- net/bluetooth/hci_conn.c | 38 ++++++++++++++++---------------- net/bluetooth/hci_core.c | 3 +++ 3 files changed, 27 insertions(+), 20 deletions(-) diff --git a/include/net/bluetooth/hci_core.h b/include/net/bluetooth/hci_core.h index f36c1fd5d64e..4f44f2bffa57 100644 --- a/include/net/bluetooth/hci_core.h +++ b/include/net/bluetooth/hci_core.h @@ -350,6 +350,8 @@ struct hci_dev { struct list_head list; struct mutex lock; + struct ida unset_handle_ida; + const char *name; unsigned long flags; __u16 id; @@ -969,6 +971,7 @@ enum { HCI_CONN_AUTH_INITIATOR, HCI_CONN_DROP, HCI_CONN_CANCEL, + HCI_CONN_DISC, HCI_CONN_PARAM_REMOVAL_PEND, HCI_CONN_NEW_LINK_KEY, HCI_CONN_SCANNING, @@ -1543,7 +1546,8 @@ static inline void hci_conn_drop(struct hci_conn *conn) { BT_DBG("hcon %p orig refcnt %d", conn, atomic_read(&conn->refcnt)); - if (atomic_dec_and_test(&conn->refcnt)) { + if (atomic_dec_and_test(&conn->refcnt) && + !test_bit(HCI_CONN_DISC, &conn->flags)) { unsigned long timeo; switch (conn->type) { diff --git a/net/bluetooth/hci_conn.c b/net/bluetooth/hci_conn.c index 974631e652c1..f87281b4386f 100644 --- a/net/bluetooth/hci_conn.c +++ b/net/bluetooth/hci_conn.c @@ -153,6 +153,9 @@ static void hci_conn_cleanup(struct hci_conn *conn) hci_conn_hash_del(hdev, conn); + if (HCI_CONN_HANDLE_UNSET(conn->handle)) + ida_free(&hdev->unset_handle_ida, conn->handle); + if (conn->cleanup) conn->cleanup(conn); @@ -929,29 +932,17 @@ static void cis_cleanup(struct hci_conn *conn) hci_le_remove_cig(hdev, conn->iso_qos.ucast.cig); } -static u16 hci_conn_hash_alloc_unset(struct hci_dev *hdev) +static int hci_conn_hash_alloc_unset(struct hci_dev *hdev) { - struct hci_conn_hash *h = &hdev->conn_hash; - struct hci_conn *c; - u16 handle = HCI_CONN_HANDLE_MAX + 1; - - rcu_read_lock(); - - list_for_each_entry_rcu(c, &h->list, list) { - /* Find the first unused handle */ - if (handle == 0xffff || c->handle != handle) - break; - handle++; - } - rcu_read_unlock(); - - return handle; + return ida_alloc_range(&hdev->unset_handle_ida, HCI_CONN_HANDLE_MAX + 1, + U16_MAX, GFP_ATOMIC); } struct hci_conn *hci_conn_add(struct hci_dev *hdev, int type, bdaddr_t *dst, u8 role) { struct hci_conn *conn; + int handle; BT_DBG("%s dst %pMR", hdev->name, dst); @@ -961,7 +952,12 @@ struct hci_conn *hci_conn_add(struct hci_dev *hdev, int type, bdaddr_t *dst, bacpy(&conn->dst, dst); bacpy(&conn->src, &hdev->bdaddr); - conn->handle = hci_conn_hash_alloc_unset(hdev); + handle = hci_conn_hash_alloc_unset(hdev); + if (unlikely(handle < 0)) { + kfree(conn); + return NULL; + } + conn->handle = handle; conn->hdev = hdev; conn->type = type; conn->role = role; @@ -2933,6 +2929,7 @@ static int abort_conn_sync(struct hci_dev *hdev, void *data) int hci_abort_conn(struct hci_conn *conn, u8 reason) { struct hci_dev *hdev = conn->hdev; + int ret; /* If abort_reason has already been set it means the connection is * already being aborted so don't attempt to overwrite it. @@ -2961,6 +2958,9 @@ int hci_abort_conn(struct hci_conn *conn, u8 reason) } } - return hci_cmd_sync_queue(hdev, abort_conn_sync, UINT_PTR(conn->handle), - NULL); + ret = hci_cmd_sync_queue(hdev, abort_conn_sync, + UINT_PTR(conn->handle), NULL); + if (!ret) + set_bit(HCI_CONN_DISC, &conn->flags); + return ret; } diff --git a/net/bluetooth/hci_core.c b/net/bluetooth/hci_core.c index 195aea2198a9..65601aa52e0d 100644 --- a/net/bluetooth/hci_core.c +++ b/net/bluetooth/hci_core.c @@ -2535,6 +2535,8 @@ struct hci_dev *hci_alloc_dev_priv(int sizeof_priv) mutex_init(&hdev->lock); mutex_init(&hdev->req_lock); + ida_init(&hdev->unset_handle_ida); + INIT_LIST_HEAD(&hdev->mesh_pending); INIT_LIST_HEAD(&hdev->mgmt_pending); INIT_LIST_HEAD(&hdev->reject_list); @@ -2789,6 +2791,7 @@ void hci_release_dev(struct hci_dev *hdev) hci_codec_list_clear(&hdev->local_codecs); hci_dev_unlock(hdev); + ida_destroy(&hdev->unset_handle_ida); ida_simple_remove(&hci_index_ida, hdev->id); kfree_skb(hdev->sent_cmd); kfree_skb(hdev->recv_event);