From patchwork Thu May 7 18:55:38 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: 215687 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=-13.6 required=3.0 tests=DKIMWL_WL_HIGH, DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI, MENTIONS_GIT_HOSTING, SIGNED_OFF_BY, SPF_HELO_NONE, SPF_PASS, USER_AGENT_SANE_1 autolearn=unavailable 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 BE858C38A24 for ; Thu, 7 May 2020 18:51:17 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 924F82495A for ; Thu, 7 May 2020 18:51:17 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1588877477; bh=oH8LQB6ff7nQSBfFV1e2P1jvW2eA3yAZZHUuknmcRH0=; h=Date:From:To:Cc:Subject:List-ID:From; b=dnTI1N3k+2VumzZP2bTAEX/n9NMlXvR+pUt/UhUg9ntYIsdXBAxDvV5Y8BFD+4Faw +CHXgMbkp+GuQ9EQhHB1fIm45socK/Ngb3KBZVrvA/ObFk4uMQ0t2XvL+JcnvclKew WJklJviIRoLLCdht/ilK+w7an5vyBPLsOLHWLWlw= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728514AbgEGSvN (ORCPT ); Thu, 7 May 2020 14:51:13 -0400 Received: from mail.kernel.org ([198.145.29.99]:52058 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726491AbgEGSvN (ORCPT ); Thu, 7 May 2020 14:51:13 -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 C57D424959; Thu, 7 May 2020 18:51:11 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1588877472; bh=oH8LQB6ff7nQSBfFV1e2P1jvW2eA3yAZZHUuknmcRH0=; h=Date:From:To:Cc:Subject:From; b=SsK1tPP7W2kSwbjdHa5jS5rf4osDLaHwaGr+e7U7/JRoj8Y1lQYdMsWQXx5hNQeoN Obtx1eGFNxukn1wgIvpeSJB9grKzxdHthFm1lyJtvoJbyJeDlvZmc6zC2ZRqbeFRP6 3mXY2tKZgX+qSBxSL1QZ+i23/HwC86kV1RJYZ/zA= Date: Thu, 7 May 2020 13:55:38 -0500 From: "Gustavo A. R. Silva" To: Johannes Berg , Emmanuel Grumbach , Luca Coelho , Intel Linux Wireless Cc: linux-wireless@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH] iwlwifi: Replace zero-length array with flexible-array Message-ID: <20200507185538.GA14674@embeddedor> MIME-Version: 1.0 Content-Disposition: inline User-Agent: Mutt/1.9.4 (2018-02-28) Sender: linux-wireless-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-wireless@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 --- drivers/net/wireless/intel/iwlwifi/dvm/commands.h | 12 ++++++------ drivers/net/wireless/intel/iwlwifi/fw/api/nvm-reg.h | 4 ++-- drivers/net/wireless/intel/iwlwifi/fw/debugfs.c | 2 +- drivers/net/wireless/intel/iwlwifi/iwl-op-mode.h | 2 +- drivers/net/wireless/intel/iwlwifi/iwl-trans.h | 2 +- 5 files changed, 11 insertions(+), 11 deletions(-) diff --git a/drivers/net/wireless/intel/iwlwifi/dvm/commands.h b/drivers/net/wireless/intel/iwlwifi/dvm/commands.h index 0f4be4be181c..fdcc1292a92b 100644 --- a/drivers/net/wireless/intel/iwlwifi/dvm/commands.h +++ b/drivers/net/wireless/intel/iwlwifi/dvm/commands.h @@ -1023,7 +1023,7 @@ struct iwl_wep_cmd { u8 global_key_type; u8 flags; u8 reserved; - struct iwl_wep_key key[0]; + struct iwl_wep_key key[]; } __packed; #define WEP_KEY_WEP_TYPE 1 @@ -1305,7 +1305,7 @@ struct iwl_tx_cmd { * length is 26 or 30 bytes, followed by payload data */ u8 payload[0]; - struct ieee80211_hdr hdr[0]; + struct ieee80211_hdr hdr[]; } __packed; /* @@ -2380,7 +2380,7 @@ struct iwl_scan_cmd { * for one scan to complete (i.e. receive SCAN_COMPLETE_NOTIFICATION) * before requesting another scan. */ - u8 data[0]; + u8 data[]; } __packed; /* Can abort will notify by complete notification with abort status. */ @@ -2475,7 +2475,7 @@ struct iwl_tx_beacon_cmd { __le16 tim_idx; u8 tim_size; u8 reserved1; - struct ieee80211_hdr frame[0]; /* beacon frame */ + struct ieee80211_hdr frame[]; /* beacon frame */ } __packed; /****************************************************************************** @@ -3188,7 +3188,7 @@ struct iwl_calib_hdr { struct iwl_calib_cmd { struct iwl_calib_hdr hdr; - u8 data[0]; + u8 data[]; } __packed; struct iwl_calib_xtal_freq_cmd { @@ -3216,7 +3216,7 @@ struct iwl_calib_temperature_offset_v2_cmd { /* IWL_PHY_CALIBRATE_CHAIN_NOISE_RESET_CMD */ struct iwl_calib_chain_noise_reset_cmd { struct iwl_calib_hdr hdr; - u8 data[0]; + u8 data[]; }; /* IWL_PHY_CALIBRATE_CHAIN_NOISE_GAIN_CMD */ diff --git a/drivers/net/wireless/intel/iwlwifi/fw/api/nvm-reg.h b/drivers/net/wireless/intel/iwlwifi/fw/api/nvm-reg.h index 97b49843e318..397ac89a04c2 100644 --- a/drivers/net/wireless/intel/iwlwifi/fw/api/nvm-reg.h +++ b/drivers/net/wireless/intel/iwlwifi/fw/api/nvm-reg.h @@ -351,7 +351,7 @@ struct iwl_mcc_update_resp_v3 { __le16 time; __le16 geo_info; __le32 n_channels; - __le32 channels[0]; + __le32 channels[]; } __packed; /* LAR_UPDATE_MCC_CMD_RESP_S_VER_3 */ /** @@ -380,7 +380,7 @@ struct iwl_mcc_update_resp { u8 source_id; u8 reserved[3]; __le32 n_channels; - __le32 channels[0]; + __le32 channels[]; } __packed; /* LAR_UPDATE_MCC_CMD_RESP_S_VER_4 */ /** diff --git a/drivers/net/wireless/intel/iwlwifi/fw/debugfs.c b/drivers/net/wireless/intel/iwlwifi/fw/debugfs.c index 89f74116569d..cc1d93606d9b 100644 --- a/drivers/net/wireless/intel/iwlwifi/fw/debugfs.c +++ b/drivers/net/wireless/intel/iwlwifi/fw/debugfs.c @@ -261,7 +261,7 @@ struct hcmd_write_data { __be32 cmd_id; __be32 flags; __be16 length; - u8 data[0]; + u8 data[]; } __packed; static ssize_t iwl_dbgfs_send_hcmd_write(struct iwl_fw_runtime *fwrt, char *buf, diff --git a/drivers/net/wireless/intel/iwlwifi/iwl-op-mode.h b/drivers/net/wireless/intel/iwlwifi/iwl-op-mode.h index 3008a5246be8..b35b8920941b 100644 --- a/drivers/net/wireless/intel/iwlwifi/iwl-op-mode.h +++ b/drivers/net/wireless/intel/iwlwifi/iwl-op-mode.h @@ -175,7 +175,7 @@ void iwl_opmode_deregister(const char *name); struct iwl_op_mode { const struct iwl_op_mode_ops *ops; - char op_mode_specific[0] __aligned(sizeof(void *)); + char op_mode_specific[] __aligned(sizeof(void *)); }; static inline void iwl_op_mode_stop(struct iwl_op_mode *op_mode) diff --git a/drivers/net/wireless/intel/iwlwifi/iwl-trans.h b/drivers/net/wireless/intel/iwlwifi/iwl-trans.h index bba527b339b5..3fbbbac0953d 100644 --- a/drivers/net/wireless/intel/iwlwifi/iwl-trans.h +++ b/drivers/net/wireless/intel/iwlwifi/iwl-trans.h @@ -878,7 +878,7 @@ struct iwl_trans { /* pointer to trans specific struct */ /*Ensure that this pointer will always be aligned to sizeof pointer */ - char trans_specific[0] __aligned(sizeof(void *)); + char trans_specific[] __aligned(sizeof(void *)); }; const char *iwl_get_cmd_string(struct iwl_trans *trans, u32 id);