From patchwork Mon Aug 14 19:01:01 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Luiz Augusto von Dentz X-Patchwork-Id: 713556 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 5D15EEB64DD for ; Mon, 14 Aug 2023 19:02:13 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229767AbjHNTBl (ORCPT ); Mon, 14 Aug 2023 15:01:41 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:55186 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231250AbjHNTBJ (ORCPT ); Mon, 14 Aug 2023 15:01:09 -0400 Received: from mail-ej1-x632.google.com (mail-ej1-x632.google.com [IPv6:2a00:1450:4864:20::632]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 1F063BC for ; Mon, 14 Aug 2023 12:01:08 -0700 (PDT) Received: by mail-ej1-x632.google.com with SMTP id a640c23a62f3a-99d6d5054bcso871166666b.1 for ; Mon, 14 Aug 2023 12:01:08 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20221208; t=1692039666; x=1692644466; h=content-transfer-encoding:mime-version:message-id:date:subject:to :from:from:to:cc:subject:date:message-id:reply-to; bh=Pk5qVNYaVnxZsg+qOi0oj4UNefLPEfzgBEE2T5Arxg0=; b=ecvYzx7LWLtAxgifRnz1BY/vXA6zElY4/J0MpEsLNjTDAKzxvQaixO74OxyXtwuyAE zkPb7bkJ0Hp9zFoPJ1RzUEoiaDHYAYh0khd4CQBz9hEaRl8wy20Oq5plCQC9h4I0eXzf /36BmihWl0NLrRG3SrWqNL6pvYTyuESEhIWnm8oNsj6kDM2Uxmfr+nWHA+OZqTMuKrzj 0QwQVk1LbUvMdf20O5DSyXjUoue6VrL/HengeAiht4ee58NXDlVwUG8niLTusIr6ClBc 4dgZ/Y+YUqIGEtwgnoLKHkAgds9l0Ujs9HABqjmzusZf3TOvmmDwwa+UR/50vfzd/7Np lkUQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20221208; t=1692039666; x=1692644466; h=content-transfer-encoding:mime-version:message-id:date:subject:to :from:x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=Pk5qVNYaVnxZsg+qOi0oj4UNefLPEfzgBEE2T5Arxg0=; b=LNsnm2ZXOfOHgCmKW+ypXQ+v4/xzQTZfi76tITP+i0od1rXclHJ/UN7v/K+kI1TNaI z6DnFqfhdPrTTxtkmey65EkvDdd7MSOtcVV2E6SLkKeOZC6UvyJx5ntc5mYXbKWkwx9i vSkRuSpz6C0hnQNkvT+Tl7tYIEfTc/YJMh87E6tMoaB9bVGClmRV8GVbz899036OEjRD 7TrDtpHLmAUnl1aitAnIxN+80FMdKGa0fVMQL/GH5RuA8fEqYeIDlkD1otyVDNhruNYZ 9uu+S45vWSBa/0sC6yhyhlFSGcUjQD59bYR2M+YwnbfjVgRt/cEZyyg4c3XlDs4S0VBn B+Hw== X-Gm-Message-State: AOJu0Yzz9A4HKChbJSJvJ3hHYMo0k76YVNSAiVcZAMkT2BenLWFB+66U G3NzGv/qFanl9vfIDFkpKiC8bymNvDs= X-Google-Smtp-Source: AGHT+IHMyLbOtT7MQGgIfEOseoiwdIaTsTDjErjmPNQ8cKdTP8aY6dRz2IrdZfIDLHm22TqcDHtJ7w== X-Received: by 2002:a17:906:5357:b0:99c:5056:4e31 with SMTP id j23-20020a170906535700b0099c50564e31mr11721894ejo.15.1692039665582; Mon, 14 Aug 2023 12:01:05 -0700 (PDT) Received: from lvondent-mobl4.. (c-98-232-221-87.hsd1.or.comcast.net. [98.232.221.87]) by smtp.gmail.com with ESMTPSA id lw12-20020a170906bccc00b0099ce23c57e6sm5983346ejb.224.2023.08.14.12.01.03 for (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 14 Aug 2023 12:01:04 -0700 (PDT) From: Luiz Augusto von Dentz To: linux-bluetooth@vger.kernel.org Subject: [PATCH v4] Bluetooth: hci_sync: Fix UAF in hci_disconnect_all_sync Date: Mon, 14 Aug 2023 12:01:01 -0700 Message-ID: <20230814190101.2302448-1-luiz.dentz@gmail.com> X-Mailer: git-send-email 2.41.0 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-bluetooth@vger.kernel.org From: Luiz Augusto von Dentz Use-after-free can occur in hci_disconnect_all_sync if a connection is deleted by concurrent processing of a controller event. To prevent this the code now tries to iterate over the list backwards to ensure the links are cleanup before its parents, also it no longer relies on a cursor, instead it always uses the last element since hci_abort_conn_sync is guaranteed to call hci_conn_del. UAF crash log: ================================================================== BUG: KASAN: slab-use-after-free in hci_set_powered_sync (net/bluetooth/hci_sync.c:5424) [bluetooth] Read of size 8 at addr ffff888009d9c000 by task kworker/u9:0/124 CPU: 0 PID: 124 Comm: kworker/u9:0 Tainted: G W 6.5.0-rc1+ #10 Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.2-1.fc38 04/01/2014 Workqueue: hci0 hci_cmd_sync_work [bluetooth] Call Trace: dump_stack_lvl+0x5b/0x90 print_report+0xcf/0x670 ? __virt_addr_valid+0xdd/0x160 ? hci_set_powered_sync+0x2c9/0x4a0 [bluetooth] kasan_report+0xa6/0xe0 ? hci_set_powered_sync+0x2c9/0x4a0 [bluetooth] ? __pfx_set_powered_sync+0x10/0x10 [bluetooth] hci_set_powered_sync+0x2c9/0x4a0 [bluetooth] ? __pfx_hci_set_powered_sync+0x10/0x10 [bluetooth] ? __pfx_lock_release+0x10/0x10 ? __pfx_set_powered_sync+0x10/0x10 [bluetooth] hci_cmd_sync_work+0x137/0x220 [bluetooth] process_one_work+0x526/0x9d0 ? __pfx_process_one_work+0x10/0x10 ? __pfx_do_raw_spin_lock+0x10/0x10 ? mark_held_locks+0x1a/0x90 worker_thread+0x92/0x630 ? __pfx_worker_thread+0x10/0x10 kthread+0x196/0x1e0 ? __pfx_kthread+0x10/0x10 ret_from_fork+0x2c/0x50 Allocated by task 1782: kasan_save_stack+0x33/0x60 kasan_set_track+0x25/0x30 __kasan_kmalloc+0x8f/0xa0 hci_conn_add+0xa5/0xa80 [bluetooth] hci_bind_cis+0x881/0x9b0 [bluetooth] iso_connect_cis+0x121/0x520 [bluetooth] iso_sock_connect+0x3f6/0x790 [bluetooth] __sys_connect+0x109/0x130 __x64_sys_connect+0x40/0x50 do_syscall_64+0x60/0x90 entry_SYSCALL_64_after_hwframe+0x6e/0xd8 Freed by task 695: kasan_save_stack+0x33/0x60 kasan_set_track+0x25/0x30 kasan_save_free_info+0x2b/0x50 __kasan_slab_free+0x10a/0x180 __kmem_cache_free+0x14d/0x2e0 device_release+0x5d/0xf0 kobject_put+0xdf/0x270 hci_disconn_complete_evt+0x274/0x3a0 [bluetooth] hci_event_packet+0x579/0x7e0 [bluetooth] hci_rx_work+0x287/0xaa0 [bluetooth] process_one_work+0x526/0x9d0 worker_thread+0x92/0x630 kthread+0x196/0x1e0 ret_from_fork+0x2c/0x50 ================================================================== Fixes: 182ee45da083 ("Bluetooth: hci_sync: Rework hci_suspend_notifier") Signed-off-by: Pauli Virtanen Signed-off-by: Luiz Augusto von Dentz --- net/bluetooth/hci_sync.c | 55 +++++++++++++++++++++++++--------------- 1 file changed, 35 insertions(+), 20 deletions(-) diff --git a/net/bluetooth/hci_sync.c b/net/bluetooth/hci_sync.c index 5eb30ba21370..d10a0f36b947 100644 --- a/net/bluetooth/hci_sync.c +++ b/net/bluetooth/hci_sync.c @@ -5370,6 +5370,7 @@ int hci_abort_conn_sync(struct hci_dev *hdev, struct hci_conn *conn, u8 reason) { int err = 0; u16 handle = conn->handle; + struct hci_conn *c; switch (conn->state) { case BT_CONNECTED: @@ -5389,43 +5390,57 @@ int hci_abort_conn_sync(struct hci_dev *hdev, struct hci_conn *conn, u8 reason) hci_dev_unlock(hdev); return 0; default: + hci_dev_lock(hdev); conn->state = BT_CLOSED; + hci_disconn_cfm(conn, reason); + hci_conn_del(conn); + hci_dev_unlock(hdev); return 0; } + hci_dev_lock(hdev); + + /* Check if the connection hasn't been cleanup while waiting + * commands to complete. + */ + c = hci_conn_hash_lookup_handle(hdev, handle); + if (!c || c != conn) { + err = 0; + goto unlock; + } + /* Cleanup hci_conn object if it cannot be cancelled as it * likelly means the controller and host stack are out of sync * or in case of LE it was still scanning so it can be cleanup * safely. */ - if (err) { - struct hci_conn *c; - - /* Check if the connection hasn't been cleanup while waiting - * commands to complete. - */ - c = hci_conn_hash_lookup_handle(hdev, handle); - if (!c || c != conn) - return 0; - - hci_dev_lock(hdev); - hci_conn_failed(conn, err); - hci_dev_unlock(hdev); - } + hci_conn_failed(conn, reason); +unlock: + hci_dev_unlock(hdev); return err; } static int hci_disconnect_all_sync(struct hci_dev *hdev, u8 reason) { - struct hci_conn *conn, *tmp; - int err; + struct list_head *head = &hdev->conn_hash.list; + struct hci_conn *conn; - list_for_each_entry_safe(conn, tmp, &hdev->conn_hash.list, list) { - err = hci_abort_conn_sync(hdev, conn, reason); - if (err) - return err; + rcu_read_lock(); + while ((conn = list_first_or_null_rcu(head, struct hci_conn, list))) { + /* Make sure the connection is not freed while unlocking */ + conn = hci_conn_get(conn); + rcu_read_unlock(); + /* Disregard possible errors since hci_conn_del shall have been + * called even in case of errors had occurred since it would + * then cause hci_conn_failed to be called which calls + * hci_conn_del internally. + */ + hci_abort_conn_sync(hdev, conn, reason); + hci_conn_put(conn); + rcu_read_lock(); } + rcu_read_unlock(); return 0; }