From patchwork Wed May 27 14:11:19 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: 218434 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 3DC02C433E1 for ; Wed, 27 May 2020 14:06:27 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 17714207D3 for ; Wed, 27 May 2020 14:06:27 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1590588387; bh=MkIk8HRQfNKTJpeG9uXaBiahdr4DaoqFGscee3N22ss=; h=Date:From:To:Cc:Subject:List-ID:From; b=lsRqH+QeCFoB9fHqi8Llkltz9AhaJmBMRi1hWIQxE+4fzYeGJMvKGCqs2NC1N694P bfJSLPMTgL2cNIijplDNCUh1Jn/5+jv0UXQ7IkTx13Xj77G4V5P/54NE1XoMCJrnNc u4Q+MAQEr4Vo1dCMI5z7S4MfOxhoBskBdt5nwGwY= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2388409AbgE0OGZ (ORCPT ); Wed, 27 May 2020 10:06:25 -0400 Received: from mail.kernel.org ([198.145.29.99]:54766 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730338AbgE0OGY (ORCPT ); Wed, 27 May 2020 10:06:24 -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 61B2C206F1; Wed, 27 May 2020 14:06:23 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1590588384; bh=MkIk8HRQfNKTJpeG9uXaBiahdr4DaoqFGscee3N22ss=; h=Date:From:To:Cc:Subject:From; b=Jj4ei4DG1vGZad9fnUD1l/lcyfWl0H2ZfbsskJwT7Sw5d7Zl9oAzFFE8Od1o2BDAy yffwR6kMJB0pTgicdUPZQNZROoS7OPA2VUwLwzn9VrddUAq2xb9AVJntI4eShdIivs q5NauugRjY0F296Oapc14WsW/000CevOcQTi8fUM= Date: Wed, 27 May 2020 09:11:19 -0500 From: "Gustavo A. R. Silva" To: Jeff Kirsher , "David S. Miller" , Jakub Kicinski Cc: intel-wired-lan@lists.osuosl.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org, "Gustavo A. R. Silva" , Kees Cook Subject: [PATCH net-next v3] ice: Replace one-element arrays with flexible-arrays Message-ID: <20200527141119.GA30849@embeddedor> MIME-Version: 1.0 Content-Disposition: inline User-Agent: Mutt/1.9.4 (2018-02-28) Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org The current codebase makes use of one-element arrays in the following form: struct something { int length; u8 data[1]; }; struct something *instance; instance = kmalloc(sizeof(*instance) + size, GFP_KERNEL); instance->length = size; memcpy(instance->data, source, size); 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. So, replace the one-element array with a flexible-array member. Also, make use of the offsetof() helper in order to simplify some macros and properly calculate the size of the structures that contain flexible-array members. This issue was found with the help of Coccinelle and, audited _manually_. [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 --- Changes in v3: - We still can simply the code even more by using offsetof() just once. :) Changes in v2: - Use offsetof(struct ice_aqc_sw_rules_elem, pdata) instead of sizeof(struct ice_aqc_sw_rules_elem) - sizeof(((struct ice_aqc_sw_rules_elem *)0)->pdata) - Update changelog text. .../net/ethernet/intel/ice/ice_adminq_cmd.h | 6 ++--- drivers/net/ethernet/intel/ice/ice_switch.c | 23 ++++++------------- 2 files changed, 10 insertions(+), 19 deletions(-) diff --git a/drivers/net/ethernet/intel/ice/ice_adminq_cmd.h b/drivers/net/ethernet/intel/ice/ice_adminq_cmd.h index 586d69491268a..faa21830e40d8 100644 --- a/drivers/net/ethernet/intel/ice/ice_adminq_cmd.h +++ b/drivers/net/ethernet/intel/ice/ice_adminq_cmd.h @@ -570,7 +570,7 @@ struct ice_sw_rule_lkup_rx_tx { * lookup-type */ __le16 hdr_len; - u8 hdr[1]; + u8 hdr[]; } __packed; /* Add/Update/Remove large action command/response entry @@ -580,7 +580,7 @@ struct ice_sw_rule_lkup_rx_tx { struct ice_sw_rule_lg_act { __le16 index; /* Index in large action table */ __le16 size; - __le32 act[1]; /* array of size for actions */ + __le32 act[]; /* array of size for actions */ /* Max number of large actions */ #define ICE_MAX_LG_ACT 4 /* Bit 0:1 - Action type */ @@ -640,7 +640,7 @@ struct ice_sw_rule_lg_act { struct ice_sw_rule_vsi_list { __le16 index; /* Index of VSI/Prune list */ __le16 number_vsi; - __le16 vsi[1]; /* Array of number_vsi VSI numbers */ + __le16 vsi[]; /* Array of number_vsi VSI numbers */ }; /* Query VSI list command/response entry */ diff --git a/drivers/net/ethernet/intel/ice/ice_switch.c b/drivers/net/ethernet/intel/ice/ice_switch.c index 0156b73df1b1f..191735ac491c6 100644 --- a/drivers/net/ethernet/intel/ice/ice_switch.c +++ b/drivers/net/ethernet/intel/ice/ice_switch.c @@ -29,25 +29,16 @@ static const u8 dummy_eth_header[DUMMY_ETH_HDR_LEN] = { 0x2, 0, 0, 0, 0, 0, 0x81, 0, 0, 0}; #define ICE_SW_RULE_RX_TX_ETH_HDR_SIZE \ - (sizeof(struct ice_aqc_sw_rules_elem) - \ - sizeof(((struct ice_aqc_sw_rules_elem *)0)->pdata) + \ - sizeof(struct ice_sw_rule_lkup_rx_tx) + DUMMY_ETH_HDR_LEN - 1) + (offsetof(struct ice_aqc_sw_rules_elem, pdata.lkup_tx_rx) + \ + DUMMY_ETH_HDR_LEN) #define ICE_SW_RULE_RX_TX_NO_HDR_SIZE \ - (sizeof(struct ice_aqc_sw_rules_elem) - \ - sizeof(((struct ice_aqc_sw_rules_elem *)0)->pdata) + \ - sizeof(struct ice_sw_rule_lkup_rx_tx) - 1) + (offsetof(struct ice_aqc_sw_rules_elem, pdata.lkup_tx_rx)) #define ICE_SW_RULE_LG_ACT_SIZE(n) \ - (sizeof(struct ice_aqc_sw_rules_elem) - \ - sizeof(((struct ice_aqc_sw_rules_elem *)0)->pdata) + \ - sizeof(struct ice_sw_rule_lg_act) - \ - sizeof(((struct ice_sw_rule_lg_act *)0)->act) + \ - ((n) * sizeof(((struct ice_sw_rule_lg_act *)0)->act))) + (offsetof(struct ice_aqc_sw_rules_elem, pdata.lg_act.act) + \ + ((n) * sizeof(__le32))) #define ICE_SW_RULE_VSI_LIST_SIZE(n) \ - (sizeof(struct ice_aqc_sw_rules_elem) - \ - sizeof(((struct ice_aqc_sw_rules_elem *)0)->pdata) + \ - sizeof(struct ice_sw_rule_vsi_list) - \ - sizeof(((struct ice_sw_rule_vsi_list *)0)->vsi) + \ - ((n) * sizeof(((struct ice_sw_rule_vsi_list *)0)->vsi))) + (offsetof(struct ice_aqc_sw_rules_elem, pdata.vsi_list.vsi) + \ + ((n) * sizeof(__le16))) /** * ice_init_def_sw_recp - initialize the recipe book keeping tables