From patchwork Thu Jun 8 21:06:42 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Pauli Virtanen X-Patchwork-Id: 13272928 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 789FFC7EE29 for ; Thu, 8 Jun 2023 21:06:56 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236986AbjFHVGz (ORCPT ); Thu, 8 Jun 2023 17:06:55 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:57424 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S236968AbjFHVGy (ORCPT ); Thu, 8 Jun 2023 17:06:54 -0400 Received: from meesny.iki.fi (meesny.iki.fi [IPv6:2001:67c:2b0:1c1::201]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 0505930C8 for ; Thu, 8 Jun 2023 14:06:50 -0700 (PDT) Received: from monolith.lan (91-152-120-101.elisa-laajakaista.fi [91.152.120.101]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) (Authenticated sender: pav) by meesny.iki.fi (Postfix) with ESMTPSA id 4QccGH65Gdzykm; Fri, 9 Jun 2023 00:06:47 +0300 (EEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=iki.fi; s=meesny; t=1686258407; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=AxQu0jI+AcZazHydptOdbBREFjCcYuiV/09/2+1LXbY=; b=L1gRwKr0VubmvoRGTbqsApDy+nXwMKoSKcS+8gbgCMtsOTGBaAOJs8Er0Ng+tSCy+NdF2L RStYEYKhHfH1oNi92ZhRk6epq72YANTZU+rMi0cQ6okgwarx4HaMeDzIXgb4eXNjFjHLju 2hEnU8EZmfsWRO3uffyRs/f0nzpvLAg= ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=iki.fi; s=meesny; t=1686258407; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=AxQu0jI+AcZazHydptOdbBREFjCcYuiV/09/2+1LXbY=; b=dL2jPyaut99T0Mi+yyGB0xGW8jxf1OnCRYW4NxDyxqH024MdIX3hep6zEX/gGpXy4q6Upk n+qk6Ir2M9J/8lw0oDH4RuscWHFIv/lji+DK71WMStxTit41s5tOtCWQ5TpBgTQ8pLzZ9Y IWTCbBclQZWPR6qZfo9f4KSoZ+2ib+Y= ARC-Authentication-Results: i=1; ORIGINATING; auth=pass smtp.auth=pav smtp.mailfrom=pav@iki.fi ARC-Seal: i=1; s=meesny; d=iki.fi; t=1686258407; a=rsa-sha256; cv=none; b=Lpk1daYRhV6li85NFrHpFRdewmwvuP7UpdPUCeWcJ2y4OiTkRRgZ6xZPyrZQGEmz264cFE ch0JSxfvsa+GmKtQoERk0IVau3+TtdX9LDhayVW4PqOowG7Ls3ZZHd26RVgmUZstk+l92E LvcH4HSP5w0DseZDQwW5UmAdeWYklBc= From: Pauli Virtanen To: linux-bluetooth@vger.kernel.org Cc: Pauli Virtanen Subject: [PATCH 1/3] Bluetooth: hci_sync: iterate over hci_conn_params safely Date: Fri, 9 Jun 2023 00:06:42 +0300 Message-Id: X-Mailer: git-send-email 2.40.1 In-Reply-To: References: MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-bluetooth@vger.kernel.org hci_update_accept_list_sync iterates over hdev->pend_le_conns and hdev->pend_le_reports, and waits for controller events in the loop body, without holding hdev lock. Meanwhile, these lists and the items may be modified e.g. by le_scan_cleanup. This can invalidate the list cursor in the ongoing iterations, resulting to invalid behavior (eg use-after-free). hdev lock should be held when operating on these lists, but it cannot be held in the loop bodies here as they block. The loops are in hci_sync, so at most one loop runs at a time (per hdev). Fix this by doing the iteration in a safe way vs. list mutation, and copy data to avoid locking. Add hci_conn_params.add_pending flag to track which items are left. Lock also around hci_pend_le_action_lookup there. This fixes the following, which can be triggered at least by changing hci_le_set_cig_params to always return false, and running BlueZ iso-tester, which causes connections to be created and dropped fast: ================================================================== BUG: KASAN: slab-use-after-free in hci_update_passive_scan_sync (net/bluetooth/hci_sync.c:2536 net/bluetooth/hci_sync.c:2723 net/bluetooth/hci_sync.c:2841) Read of size 8 at addr ffff888001265018 by task kworker/u3:0/32 Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.2-1.fc38 04/01/2014 Workqueue: hci0 hci_cmd_sync_work Call Trace: dump_stack_lvl (./arch/x86/include/asm/irqflags.h:134 lib/dump_stack.c:107) print_report (mm/kasan/report.c:320 mm/kasan/report.c:430) ? __virt_addr_valid (./include/linux/mmzone.h:1915 ./include/linux/mmzone.h:2011 arch/x86/mm/physaddr.c:65) ? hci_update_passive_scan_sync (net/bluetooth/hci_sync.c:2536 net/bluetooth/hci_sync.c:2723 net/bluetooth/hci_sync.c:2841) kasan_report (mm/kasan/report.c:538) ? hci_update_passive_scan_sync (net/bluetooth/hci_sync.c:2536 net/bluetooth/hci_sync.c:2723 net/bluetooth/hci_sync.c:2841) hci_update_passive_scan_sync (net/bluetooth/hci_sync.c:2536 net/bluetooth/hci_sync.c:2723 net/bluetooth/hci_sync.c:2841) ? __pfx_hci_update_passive_scan_sync (net/bluetooth/hci_sync.c:2780) ? mutex_lock (kernel/locking/mutex.c:282) ? __pfx_mutex_lock (kernel/locking/mutex.c:282) ? __pfx_mutex_unlock (kernel/locking/mutex.c:538) ? __pfx_update_passive_scan_sync (net/bluetooth/hci_sync.c:2861) hci_cmd_sync_work (net/bluetooth/hci_sync.c:306) process_one_work (./arch/x86/include/asm/preempt.h:27 kernel/workqueue.c:2399) worker_thread (./include/linux/list.h:292 kernel/workqueue.c:2538) ? __pfx_worker_thread (kernel/workqueue.c:2480) kthread (kernel/kthread.c:376) ? __pfx_kthread (kernel/kthread.c:331) ret_from_fork (arch/x86/entry/entry_64.S:314) Allocated by task 31: kasan_save_stack (mm/kasan/common.c:46) kasan_set_track (mm/kasan/common.c:52) __kasan_kmalloc (mm/kasan/common.c:374 mm/kasan/common.c:383) hci_conn_params_add (./include/linux/slab.h:580 ./include/linux/slab.h:720 net/bluetooth/hci_core.c:2277) hci_connect_le_scan (net/bluetooth/hci_conn.c:1419 net/bluetooth/hci_conn.c:1589) hci_connect_cis (net/bluetooth/hci_conn.c:2266) iso_connect_cis (net/bluetooth/iso.c:390) iso_sock_connect (net/bluetooth/iso.c:899) __sys_connect (net/socket.c:2003 net/socket.c:2020) __x64_sys_connect (net/socket.c:2027) do_syscall_64 (arch/x86/entry/common.c:50 arch/x86/entry/common.c:80) entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:120) Freed by task 15: kasan_save_stack (mm/kasan/common.c:46) kasan_set_track (mm/kasan/common.c:52) kasan_save_free_info (mm/kasan/generic.c:523) __kasan_slab_free (mm/kasan/common.c:238 mm/kasan/common.c:200 mm/kasan/common.c:244) __kmem_cache_free (mm/slub.c:1807 mm/slub.c:3787 mm/slub.c:3800) hci_conn_params_del (net/bluetooth/hci_core.c:2323) le_scan_cleanup (net/bluetooth/hci_conn.c:202) process_one_work (./arch/x86/include/asm/preempt.h:27 kernel/workqueue.c:2399) worker_thread (./include/linux/list.h:292 kernel/workqueue.c:2538) kthread (kernel/kthread.c:376) ret_from_fork (arch/x86/entry/entry_64.S:314) ================================================================== Fixes: e8907f76544f ("Bluetooth: hci_sync: Make use of hci_cmd_sync_queue set 3") Signed-off-by: Pauli Virtanen --- Notes: It might be that even more of hci_passive_scan_sync and the routines it calls should hold hdev->lock, but don't know that right now. include/net/bluetooth/hci_core.h | 1 + net/bluetooth/hci_sync.c | 81 ++++++++++++++++++++++++++++---- 2 files changed, 74 insertions(+), 8 deletions(-) diff --git a/include/net/bluetooth/hci_core.h b/include/net/bluetooth/hci_core.h index 683666ea210c..e79b3831fcf3 100644 --- a/include/net/bluetooth/hci_core.h +++ b/include/net/bluetooth/hci_core.h @@ -822,6 +822,7 @@ struct hci_conn_params { struct hci_conn *conn; bool explicit_connect; + bool add_pending; hci_conn_flags_t flags; u8 privacy_mode; }; diff --git a/net/bluetooth/hci_sync.c b/net/bluetooth/hci_sync.c index 97da5bcaa904..e6fde15dc9ca 100644 --- a/net/bluetooth/hci_sync.c +++ b/net/bluetooth/hci_sync.c @@ -2160,15 +2160,23 @@ static int hci_le_del_accept_list_sync(struct hci_dev *hdev, return 0; } +struct conn_params { + bdaddr_t addr; + u8 addr_type; + hci_conn_flags_t flags; + u8 privacy_mode; +}; + /* Adds connection to resolve list if needed. * Setting params to NULL programs local hdev->irk */ static int hci_le_add_resolve_list_sync(struct hci_dev *hdev, - struct hci_conn_params *params) + struct conn_params *params) { struct hci_cp_le_add_to_resolv_list cp; struct smp_irk *irk; struct bdaddr_list_with_irk *entry; + struct hci_conn_params *hparams; if (!use_ll_privacy(hdev)) return 0; @@ -2203,6 +2211,13 @@ static int hci_le_add_resolve_list_sync(struct hci_dev *hdev, /* Default privacy mode is always Network */ params->privacy_mode = HCI_NETWORK_PRIVACY; + hci_dev_lock(hdev); + hparams = hci_conn_params_lookup(hdev, ¶ms->addr, + params->addr_type); + if (hparams) + hparams->privacy_mode = HCI_NETWORK_PRIVACY; + hci_dev_unlock(hdev); + done: if (hci_dev_test_flag(hdev, HCI_PRIVACY)) memcpy(cp.local_irk, hdev->irk, 16); @@ -2215,7 +2230,7 @@ static int hci_le_add_resolve_list_sync(struct hci_dev *hdev, /* Set Device Privacy Mode. */ static int hci_le_set_privacy_mode_sync(struct hci_dev *hdev, - struct hci_conn_params *params) + struct conn_params *params) { struct hci_cp_le_set_privacy_mode cp; struct smp_irk *irk; @@ -2249,7 +2264,7 @@ static int hci_le_set_privacy_mode_sync(struct hci_dev *hdev, * properly set the privacy mode. */ static int hci_le_add_accept_list_sync(struct hci_dev *hdev, - struct hci_conn_params *params, + struct conn_params *params, u8 *num_entries) { struct hci_cp_le_add_to_accept_list cp; @@ -2447,6 +2462,37 @@ struct sk_buff *hci_read_local_oob_data_sync(struct hci_dev *hdev, return __hci_cmd_sync_sk(hdev, opcode, 0, NULL, 0, HCI_CMD_TIMEOUT, sk); } +static void conn_params_iter_init(struct list_head *list) +{ + struct hci_conn_params *params; + + list_for_each_entry(params, list, action) + params->add_pending = true; +} + +static bool conn_params_iter_next(struct list_head *list, + struct conn_params *item) +{ + struct hci_conn_params *params; + + /* Must hold hdev lock. Not reentrant. Mutating list is allowed. */ + + list_for_each_entry(params, list, action) { + if (!params->add_pending) + continue; + + memcpy(&item->addr, ¶ms->addr, sizeof(params->addr)); + item->addr_type = params->addr_type; + item->privacy_mode = params->privacy_mode; + item->flags = params->flags; + + params->add_pending = false; + return true; + } + + return false; +} + /* Device must not be scanning when updating the accept list. * * Update is done using the following sequence: @@ -2466,7 +2512,7 @@ struct sk_buff *hci_read_local_oob_data_sync(struct hci_dev *hdev, */ static u8 hci_update_accept_list_sync(struct hci_dev *hdev) { - struct hci_conn_params *params; + struct conn_params params; struct bdaddr_list *b, *t; u8 num_entries = 0; bool pend_conn, pend_report; @@ -2494,6 +2540,8 @@ static u8 hci_update_accept_list_sync(struct hci_dev *hdev) goto done; } + hci_dev_lock(hdev); + /* Go through the current accept list programmed into the * controller one by one and check if that address is connected or is * still in the list of pending connections or list of devices to @@ -2515,8 +2563,10 @@ static u8 hci_update_accept_list_sync(struct hci_dev *hdev) * remove it from the acceptlist. */ if (!pend_conn && !pend_report) { + hci_dev_unlock(hdev); hci_le_del_accept_list_sync(hdev, &b->bdaddr, b->bdaddr_type); + hci_dev_lock(hdev); continue; } @@ -2532,23 +2582,38 @@ static u8 hci_update_accept_list_sync(struct hci_dev *hdev) * available accept list entries in the controller, then * just abort and return filer policy value to not use the * accept list. + * + * The list may be mutated at any time outside hdev lock, + * so use special iteration with copies. */ - list_for_each_entry(params, &hdev->pend_le_conns, action) { - err = hci_le_add_accept_list_sync(hdev, params, &num_entries); + + conn_params_iter_init(&hdev->pend_le_conns); + + while (conn_params_iter_next(&hdev->pend_le_conns, ¶ms)) { + hci_dev_unlock(hdev); + err = hci_le_add_accept_list_sync(hdev, ¶ms, &num_entries); if (err) goto done; + hci_dev_lock(hdev); } /* After adding all new pending connections, walk through * the list of pending reports and also add these to the * accept list if there is still space. Abort if space runs out. */ - list_for_each_entry(params, &hdev->pend_le_reports, action) { - err = hci_le_add_accept_list_sync(hdev, params, &num_entries); + + conn_params_iter_init(&hdev->pend_le_reports); + + while (conn_params_iter_next(&hdev->pend_le_reports, ¶ms)) { + hci_dev_unlock(hdev); + err = hci_le_add_accept_list_sync(hdev, ¶ms, &num_entries); if (err) goto done; + hci_dev_lock(hdev); } + hci_dev_unlock(hdev); + /* Use the allowlist unless the following conditions are all true: * - We are not currently suspending * - There are 1 or more ADV monitors registered and it's not offloaded