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=-10.1 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,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 8EEF2C76191 for ; Mon, 15 Jul 2019 14:28:02 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 652CF20896 for ; Mon, 15 Jul 2019 14:28:02 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1563200882; bh=SbEH40A99/CV4klBOaA1lpJjoIMpOGg6K6xG/CnHSDI=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=diULyj6DWWZ86B4nlxL3lD1/N5OFkCiC5mTzlwvmHGiKRB+gu+v3lWWJ7vyOu5tuL 3WlIOS/eHXwNcmwcsY81cjTJNOn26dA+ow5crZ9HCjejKgwi4s9vHsYeb7VM/DBL2d 5OM94eva0yNbcGjYP612knUen4lFKnCBLJ5BNmF8= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2391128AbfGOO2B (ORCPT ); Mon, 15 Jul 2019 10:28:01 -0400 Received: from mail.kernel.org ([198.145.29.99]:37876 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2403758AbfGOO2A (ORCPT ); Mon, 15 Jul 2019 10:28:00 -0400 Received: from sasha-vm.mshome.net (unknown [73.61.17.35]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 3789220896; Mon, 15 Jul 2019 14:27:56 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1563200879; bh=SbEH40A99/CV4klBOaA1lpJjoIMpOGg6K6xG/CnHSDI=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=t8dkYaQjkfgWmV9CuN/Ed9zDe3A1ycGbBdb/unxp7PIc59aIx15SIebToONCxk5/v Xp2aDN1k7Zdfq4dI8A97V+X9y070klKJE/KQHjfTAVQJ3XfdykU6ujkfA0QxOCtuvl PvdQ1I72CA2VelfFpAtcHT9fv92HO74CO2oHm/HQ= From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: csonsino , Marcel Holtmann , Sasha Levin , linux-bluetooth@vger.kernel.org, netdev@vger.kernel.org Subject: [PATCH AUTOSEL 4.19 153/158] Bluetooth: validate BLE connection interval updates Date: Mon, 15 Jul 2019 10:18:04 -0400 Message-Id: <20190715141809.8445-153-sashal@kernel.org> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20190715141809.8445-1-sashal@kernel.org> References: <20190715141809.8445-1-sashal@kernel.org> MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit Sender: linux-bluetooth-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-bluetooth@vger.kernel.org From: csonsino [ 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 3e7badb3ac2d..0adcddb211fa 100644 --- a/net/bluetooth/hci_event.c +++ b/net/bluetooth/hci_event.c @@ -5545,6 +5545,11 @@ 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 260ef5426e0c..a54dadf4a6ca 100644 --- a/net/bluetooth/l2cap_core.c +++ b/net/bluetooth/l2cap_core.c @@ -5287,7 +5287,14 @@ 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