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=-9.8 required=3.0 tests=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=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 CB9C5C32750 for ; Fri, 2 Aug 2019 09:43:59 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id A250D20679 for ; Fri, 2 Aug 2019 09:43:59 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1564739039; bh=T22cdQWK5a/PAaS4hKVglKPJaPKjkRVL1RkhOvh+v18=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=S66FxhIDeOsCVvl6AGOwbbWV4vKfhGdN6uI7nuQ1paOyu1IECv9mrcMICl1bGQ1gC U8uzCoA8jML4yXj9sXNztMZUIqbK6+1DjnaAsSx9PsbBsyuNoP+49ehdIP74dC9PGO JMQ6SV92I8nLZt5owxvyveLuKlyQYDu78JBHdmJw= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2403915AbfHBJn5 (ORCPT ); Fri, 2 Aug 2019 05:43:57 -0400 Received: from mail.kernel.org ([198.145.29.99]:46960 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2405132AbfHBJnx (ORCPT ); Fri, 2 Aug 2019 05:43:53 -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 61CF320679; Fri, 2 Aug 2019 09:43:51 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1564739031; bh=T22cdQWK5a/PAaS4hKVglKPJaPKjkRVL1RkhOvh+v18=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=xV6E7fQhCRByQeL995nIR7f+KLqV33YK8FfgbrQwtsWOB8zA39fbl9GrdbMpUlYdo nZlaZrflO841sy4datvZuBXlAm/TF0q4LrlVmZ8JZ1SQm1HFoSmarnCigSZ74QAXFf XPtOmh5apc1EK2lGSvYsrxLZo3XkKYzd/AZH8gDI= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Carey Sonsino , Marcel Holtmann , Sasha Levin Subject: [PATCH 4.9 071/223] Bluetooth: validate BLE connection interval updates Date: Fri, 2 Aug 2019 11:34:56 +0200 Message-Id: <20190802092243.409765671@linuxfoundation.org> X-Mailer: git-send-email 2.22.0 In-Reply-To: <20190802092238.692035242@linuxfoundation.org> References: <20190802092238.692035242@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 [ Upstream commit c49a8682fc5d298d44e8d911f4fa14690ea9485e ] Problem: The Linux Bluetooth stack yields complete control over the BLE connection interval to the remote device. The Linux Bluetooth stack provides access to the BLE connection interval min and max values through /sys/kernel/debug/bluetooth/hci0/ conn_min_interval and /sys/kernel/debug/bluetooth/hci0/conn_max_interval. These values are used for initial BLE connections, but the remote device has the ability to request a connection parameter update. In the event that the remote side requests to change the connection interval, the Linux kernel currently only validates that the desired value is within the acceptable range in the Bluetooth specification (6 - 3200, corresponding to 7.5ms - 4000ms). There is currently no validation that the desired value requested by the remote device is within the min/max limits specified in the conn_min_interval/conn_max_interval configurations. This essentially leads to Linux yielding complete control over the connection interval to the remote device. The proposed patch adds a verification step to the connection parameter update mechanism, ensuring that the desired value is within the min/max bounds of the current connection. If the desired value is outside of the current connection min/max values, then the connection parameter update request is rejected and the negative response is returned to the remote device. Recall that the initial connection is established using the local conn_min_interval/conn_max_interval values, so this allows the Linux administrator to retain control over the BLE connection interval. The one downside that I see is that the current default Linux values for conn_min_interval and conn_max_interval typically correspond to 30ms and 50ms respectively. If this change were accepted, then it is feasible that some devices would no longer be able to negotiate to their desired connection interval values. This might be remedied by setting the default Linux conn_min_interval and conn_max_interval values to the widest supported range (6 - 3200 / 7.5ms - 4000ms). This could lead to the same behavior as the current implementation, where the remote device could request to change the connection interval value to any value that is permitted by the Bluetooth specification, and Linux would accept the desired value. Signed-off-by: Carey Sonsino Signed-off-by: Marcel Holtmann Signed-off-by: Sasha Levin --- net/bluetooth/hci_event.c | 5 +++++ net/bluetooth/l2cap_core.c | 9 ++++++++- 2 files changed, 13 insertions(+), 1 deletion(-) diff --git a/net/bluetooth/hci_event.c b/net/bluetooth/hci_event.c index 6f78489fdb13..163a239bda91 100644 --- a/net/bluetooth/hci_event.c +++ b/net/bluetooth/hci_event.c @@ -5089,6 +5089,11 @@ static void hci_le_remote_conn_param_req_evt(struct hci_dev *hdev, return send_conn_param_neg_reply(hdev, handle, HCI_ERROR_UNKNOWN_CONN_ID); + if (min < hcon->le_conn_min_interval || + max > hcon->le_conn_max_interval) + return send_conn_param_neg_reply(hdev, handle, + HCI_ERROR_INVALID_LL_PARAMS); + if (hci_check_conn_params(min, max, latency, timeout)) return send_conn_param_neg_reply(hdev, handle, HCI_ERROR_INVALID_LL_PARAMS); diff --git a/net/bluetooth/l2cap_core.c b/net/bluetooth/l2cap_core.c index 48d23abfe799..4912e80dacef 100644 --- a/net/bluetooth/l2cap_core.c +++ b/net/bluetooth/l2cap_core.c @@ -5277,7 +5277,14 @@ static inline int l2cap_conn_param_update_req(struct l2cap_conn *conn, memset(&rsp, 0, sizeof(rsp)); - err = hci_check_conn_params(min, max, latency, to_multiplier); + if (min < hcon->le_conn_min_interval || + max > hcon->le_conn_max_interval) { + BT_DBG("requested connection interval exceeds current bounds."); + err = -EINVAL; + } else { + err = hci_check_conn_params(min, max, latency, to_multiplier); + } + if (err) rsp.result = cpu_to_le16(L2CAP_CONN_PARAM_REJECTED); else -- 2.20.1