From patchwork Thu May 7 18:50:50 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Gustavo A. R. Silva" X-Patchwork-Id: 11534681 X-Patchwork-Delegate: marcel@holtmann.org Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 1411C15AB for ; Thu, 7 May 2020 18:46:29 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id ECAAE2145D for ; Thu, 7 May 2020 18:46:28 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1588877189; bh=BAszGG+DTOlyS0kCl+6JphswFfRjGJgoGAsHyQBqMOA=; h=Date:From:To:Cc:Subject:List-ID:From; b=V6TG1SQ/+ydYgclB3vsj7lWNogYxJ1o4aJSgoKHTffS1L9l1KYav8Qk46vISCPcLN TWN3e9HyfVmdmkbD7TB3pgFRP2Imv1k9AWIReT1JkRLvrRx9cYeseUXi2wsBgYuPM0 ff6mUEsdR/Pdq94/vnAVthXm1HRSeq36U2KgecQ8= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727117AbgEGSqZ (ORCPT ); Thu, 7 May 2020 14:46:25 -0400 Received: from mail.kernel.org ([198.145.29.99]:46988 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726491AbgEGSqZ (ORCPT ); Thu, 7 May 2020 14:46:25 -0400 Received: from embeddedor (unknown [189.207.59.248]) (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 039B9216FD; Thu, 7 May 2020 18:46:23 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1588877184; bh=BAszGG+DTOlyS0kCl+6JphswFfRjGJgoGAsHyQBqMOA=; h=Date:From:To:Cc:Subject:From; b=uIoCjQSHnTZORL1yOSkWc16nPMM3BKxY+n2f0COZl4NBDdU62Kd4sBuAUswTFlPP/ khvF95KhPuJt1uamOwuioxv5NkfmvVIQDxq9dsOApJM3FPlA6xSHSxtj+j3Qou6E6G p68YYsq3b9nUP9etw3ruxaeE8Smo720E8GPEGg2s= Date: Thu, 7 May 2020 13:50:50 -0500 From: "Gustavo A. R. Silva" To: Marcel Holtmann , Johan Hedberg Cc: linux-bluetooth@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH] Bluetooth: Replace zero-length array with flexible-array Message-ID: <20200507185050.GA13953@embeddedor> MIME-Version: 1.0 Content-Disposition: inline User-Agent: Mutt/1.9.4 (2018-02-28) Sender: linux-bluetooth-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-bluetooth@vger.kernel.org The current codebase makes use of the zero-length array language extension to the C90 standard, but the preferred mechanism to declare variable-length types such as these ones is a flexible array member[1][2], introduced in C99: struct foo { int stuff; struct boo array[]; }; By making use of the mechanism above, we will get a compiler warning in case the flexible array does not occur last in the structure, which will help us prevent some kind of undefined behavior bugs from being inadvertently introduced[3] to the codebase from now on. Also, notice that, dynamic memory allocations won't be affected by this change: "Flexible array members have incomplete type, and so the sizeof operator may not be applied. As a quirk of the original implementation of zero-length arrays, sizeof evaluates to zero."[1] sizeof(flexible-array-member) triggers a warning because flexible array members have incomplete type[1]. There are some instances of code in which the sizeof operator is being incorrectly/erroneously applied to zero-length arrays and the result is zero. Such instances may be hiding some bugs. So, this work (flexible-array member conversions) will also help to get completely rid of those sorts of issues. This issue was found with the help of Coccinelle. [1] https://gcc.gnu.org/onlinedocs/gcc/Zero-Length.html [2] https://github.com/KSPP/linux/issues/21 [3] commit 76497732932f ("cxgb3/l2t: Fix undefined behaviour") Signed-off-by: Gustavo A. R. Silva --- include/net/bluetooth/l2cap.h | 6 +++--- include/net/bluetooth/mgmt.h | 40 ++++++++++++++++++++-------------------- 2 files changed, 23 insertions(+), 23 deletions(-) diff --git a/include/net/bluetooth/l2cap.h b/include/net/bluetooth/l2cap.h index dada14d0622c..8f1e6a7a2df8 100644 --- a/include/net/bluetooth/l2cap.h +++ b/include/net/bluetooth/l2cap.h @@ -499,7 +499,7 @@ struct l2cap_ecred_conn_req { __le16 mtu; __le16 mps; __le16 credits; - __le16 scid[0]; + __le16 scid[]; } __packed; struct l2cap_ecred_conn_rsp { @@ -507,13 +507,13 @@ struct l2cap_ecred_conn_rsp { __le16 mps; __le16 credits; __le16 result; - __le16 dcid[0]; + __le16 dcid[]; }; struct l2cap_ecred_reconf_req { __le16 mtu; __le16 mps; - __le16 scid[0]; + __le16 scid[]; } __packed; #define L2CAP_RECONF_SUCCESS 0x0000 diff --git a/include/net/bluetooth/mgmt.h b/include/net/bluetooth/mgmt.h index f41cd87550dc..e104329e227f 100644 --- a/include/net/bluetooth/mgmt.h +++ b/include/net/bluetooth/mgmt.h @@ -70,14 +70,14 @@ struct mgmt_rp_read_version { struct mgmt_rp_read_commands { __le16 num_commands; __le16 num_events; - __le16 opcodes[0]; + __le16 opcodes[]; } __packed; #define MGMT_OP_READ_INDEX_LIST 0x0003 #define MGMT_READ_INDEX_LIST_SIZE 0 struct mgmt_rp_read_index_list { __le16 num_controllers; - __le16 index[0]; + __le16 index[]; } __packed; /* Reserve one extra byte for names in management messages so that they @@ -183,7 +183,7 @@ struct mgmt_link_key_info { struct mgmt_cp_load_link_keys { __u8 debug_keys; __le16 key_count; - struct mgmt_link_key_info keys[0]; + struct mgmt_link_key_info keys[]; } __packed; #define MGMT_LOAD_LINK_KEYS_SIZE 3 @@ -206,7 +206,7 @@ struct mgmt_ltk_info { #define MGMT_OP_LOAD_LONG_TERM_KEYS 0x0013 struct mgmt_cp_load_long_term_keys { __le16 key_count; - struct mgmt_ltk_info keys[0]; + struct mgmt_ltk_info keys[]; } __packed; #define MGMT_LOAD_LONG_TERM_KEYS_SIZE 2 @@ -223,7 +223,7 @@ struct mgmt_rp_disconnect { #define MGMT_GET_CONNECTIONS_SIZE 0 struct mgmt_rp_get_connections { __le16 conn_count; - struct mgmt_addr_info addr[0]; + struct mgmt_addr_info addr[]; } __packed; #define MGMT_OP_PIN_CODE_REPLY 0x0016 @@ -413,7 +413,7 @@ struct mgmt_irk_info { #define MGMT_OP_LOAD_IRKS 0x0030 struct mgmt_cp_load_irks { __le16 irk_count; - struct mgmt_irk_info irks[0]; + struct mgmt_irk_info irks[]; } __packed; #define MGMT_LOAD_IRKS_SIZE 2 @@ -465,7 +465,7 @@ struct mgmt_conn_param { #define MGMT_OP_LOAD_CONN_PARAM 0x0035 struct mgmt_cp_load_conn_param { __le16 param_count; - struct mgmt_conn_param params[0]; + struct mgmt_conn_param params[]; } __packed; #define MGMT_LOAD_CONN_PARAM_SIZE 2 @@ -473,7 +473,7 @@ struct mgmt_cp_load_conn_param { #define MGMT_READ_UNCONF_INDEX_LIST_SIZE 0 struct mgmt_rp_read_unconf_index_list { __le16 num_controllers; - __le16 index[0]; + __le16 index[]; } __packed; #define MGMT_OPTION_EXTERNAL_CONFIG 0x00000001 @@ -504,7 +504,7 @@ struct mgmt_cp_start_service_discovery { __u8 type; __s8 rssi; __le16 uuid_count; - __u8 uuids[0][16]; + __u8 uuids[][16]; } __packed; #define MGMT_START_SERVICE_DISCOVERY_SIZE 4 @@ -516,7 +516,7 @@ struct mgmt_cp_read_local_oob_ext_data { struct mgmt_rp_read_local_oob_ext_data { __u8 type; __le16 eir_len; - __u8 eir[0]; + __u8 eir[]; } __packed; #define MGMT_OP_READ_EXT_INDEX_LIST 0x003C @@ -527,7 +527,7 @@ struct mgmt_rp_read_ext_index_list { __le16 index; __u8 type; __u8 bus; - } entry[0]; + } entry[]; } __packed; #define MGMT_OP_READ_ADV_FEATURES 0x0003D @@ -538,7 +538,7 @@ struct mgmt_rp_read_adv_features { __u8 max_scan_rsp_len; __u8 max_instances; __u8 num_instances; - __u8 instance[0]; + __u8 instance[]; } __packed; #define MGMT_OP_ADD_ADVERTISING 0x003E @@ -549,7 +549,7 @@ struct mgmt_cp_add_advertising { __le16 timeout; __u8 adv_data_len; __u8 scan_rsp_len; - __u8 data[0]; + __u8 data[]; } __packed; #define MGMT_ADD_ADVERTISING_SIZE 11 struct mgmt_rp_add_advertising { @@ -603,7 +603,7 @@ struct mgmt_rp_read_ext_info { __le32 supported_settings; __le32 current_settings; __le16 eir_len; - __u8 eir[0]; + __u8 eir[]; } __packed; #define MGMT_OP_SET_APPEARANCE 0x0043 @@ -668,7 +668,7 @@ struct mgmt_blocked_key_info { struct mgmt_cp_set_blocked_keys { __le16 key_count; - struct mgmt_blocked_key_info keys[0]; + struct mgmt_blocked_key_info keys[]; } __packed; #define MGMT_OP_SET_BLOCKED_KEYS_SIZE 2 @@ -678,7 +678,7 @@ struct mgmt_cp_set_blocked_keys { struct mgmt_ev_cmd_complete { __le16 opcode; __u8 status; - __u8 data[0]; + __u8 data[]; } __packed; #define MGMT_EV_CMD_STATUS 0x0002 @@ -726,7 +726,7 @@ struct mgmt_ev_device_connected { struct mgmt_addr_info addr; __le32 flags; __le16 eir_len; - __u8 eir[0]; + __u8 eir[]; } __packed; #define MGMT_DEV_DISCONN_UNKNOWN 0x00 @@ -781,7 +781,7 @@ struct mgmt_ev_device_found { __s8 rssi; __le32 flags; __le16 eir_len; - __u8 eir[0]; + __u8 eir[]; } __packed; #define MGMT_EV_DISCOVERING 0x0013 @@ -876,7 +876,7 @@ struct mgmt_ev_ext_index { struct mgmt_ev_local_oob_data_updated { __u8 type; __le16 eir_len; - __u8 eir[0]; + __u8 eir[]; } __packed; #define MGMT_EV_ADVERTISING_ADDED 0x0023 @@ -892,7 +892,7 @@ struct mgmt_ev_advertising_removed { #define MGMT_EV_EXT_INFO_CHANGED 0x0025 struct mgmt_ev_ext_info_changed { __le16 eir_len; - __u8 eir[0]; + __u8 eir[]; } __packed; #define MGMT_EV_PHY_CONFIGURATION_CHANGED 0x0026