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=-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,URIBL_BLOCKED, USER_AGENT_SANE_1 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 D096FC38A24 for ; Thu, 7 May 2020 18:46:17 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id A9E74216FD for ; Thu, 7 May 2020 18:46:17 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1588877177; bh=LY2jkV97lN6hlH+aNy6zJIMhsQoeDUU78bNRPuu10Lg=; h=Date:From:To:Cc:Subject:List-ID:From; b=BsJVAsPPtS8Uto2yHinsawOAYYlRxaU0/8Yq9ZgFVxX9GgiYO+HWWPrwkNCsmFalR OyZdPnMin4Bz9W/l93vvF0y5GcoAL/cpzI/F9I3ciKvjebeh/td+efl7sk8giASrnU qTHrubawZurizMXS4Z8Gm+j3/8K0RD6HaKnIioWA= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728380AbgEGSqQ (ORCPT ); Thu, 7 May 2020 14:46:16 -0400 Received: from mail.kernel.org ([198.145.29.99]:46890 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726320AbgEGSqQ (ORCPT ); Thu, 7 May 2020 14:46:16 -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 0506920A8B; Thu, 7 May 2020 18:46:14 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1588877175; bh=LY2jkV97lN6hlH+aNy6zJIMhsQoeDUU78bNRPuu10Lg=; h=Date:From:To:Cc:Subject:From; b=qaCFnXGQcpFD5+QW2rfWRy19qDQqnESmRzfqJip40k6Fa0Ri0iG0QcVKGwau4NcW0 L1CQpQ7yLlvQGdreog2rIPSeJxca/P8ideP7JpFccRnvqF99JtvdkoROIHPUi9BB1Z Hoeao9mfl8CfTde0VxNcDWpbuO97z7xw7n2Afaew= Date: Thu, 7 May 2020 13:50:41 -0500 From: "Gustavo A. R. Silva" To: Paul Moore , Eric Paris Cc: linux-audit@redhat.com, linux-kernel@vger.kernel.org Subject: [PATCH] audit: Replace zero-length array with flexible-array Message-ID: <20200507185041.GA13930@embeddedor> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline User-Agent: Mutt/1.9.4 (2018-02-28) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@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/linux/audit.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/include/linux/audit.h b/include/linux/audit.h index f9ceae57ca8d..2b63aee6e9fa 100644 --- a/include/linux/audit.h +++ b/include/linux/audit.h @@ -19,7 +19,7 @@ struct audit_sig_info { uid_t uid; pid_t pid; - char ctx[0]; + char ctx[]; }; struct audit_buffer; 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=-13.5 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,INCLUDES_PATCH,MAILING_LIST_MULTI,MENTIONS_GIT_HOSTING, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 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 B91BAC38A24 for ; Thu, 7 May 2020 19:09:53 +0000 (UTC) Received: from us-smtp-1.mimecast.com (us-smtp-delivery-1.mimecast.com [207.211.31.120]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 6316C2173E for ; Thu, 7 May 2020 19:09:53 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="b6/Gbc3f" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 6316C2173E Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=kernel.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=linux-audit-bounces@redhat.com DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1588878592; h=from:from:sender:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding:list-id:list-help: list-unsubscribe:list-subscribe:list-post; bh=5gciNdJRtgYErbXDC7y8zUklAip2SUkVpUGZS/gOCUQ=; b=b6/Gbc3f/6VV2ziE0rg+6GL4+cvKJvpsURFZsdoo8GaossVnL6uPooVXcKaXbKFU5iFoFr R/LcFNaeRR2xRhQdYetad6p9QAJGl8Eq4Wvtaoa8F/JyvgfZFv/+CgPdqfTI2486Nhya+M 6dhZgiZHFiRAbEJ0JAagMRfjM2qcgx8= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-257-v509OA0YMye3viqFfIHE2A-1; Thu, 07 May 2020 15:09:50 -0400 X-MC-Unique: v509OA0YMye3viqFfIHE2A-1 Received: from smtp.corp.redhat.com (int-mx03.intmail.prod.int.phx2.redhat.com [10.5.11.13]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id E099519057A0; Thu, 7 May 2020 19:09:45 +0000 (UTC) Received: from colo-mx.corp.redhat.com (colo-mx02.intmail.prod.int.phx2.redhat.com [10.5.11.21]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 018EB70545; Thu, 7 May 2020 19:09:45 +0000 (UTC) Received: from lists01.pubmisc.prod.ext.phx2.redhat.com (lists01.pubmisc.prod.ext.phx2.redhat.com [10.5.19.33]) by colo-mx.corp.redhat.com (Postfix) with ESMTP id 58C0A4CAA0; Thu, 7 May 2020 19:09:43 +0000 (UTC) Received: from smtp.corp.redhat.com (int-mx06.intmail.prod.int.rdu2.redhat.com [10.11.54.6]) by lists01.pubmisc.prod.ext.phx2.redhat.com (8.13.8/8.13.8) with ESMTP id 047IrfcG016437 for ; Thu, 7 May 2020 14:53:41 -0400 Received: by smtp.corp.redhat.com (Postfix) id 5184B2157F26; Thu, 7 May 2020 18:53:41 +0000 (UTC) Received: from mimecast-mx02.redhat.com (mimecast03.extmail.prod.ext.rdu2.redhat.com [10.11.55.19]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 4C1F52156A3A for ; Thu, 7 May 2020 18:53:38 +0000 (UTC) Received: from us-smtp-1.mimecast.com (us-smtp-delivery-1.mimecast.com [207.211.31.120]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-SHA384 (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 9A80380030B for ; Thu, 7 May 2020 18:53:38 +0000 (UTC) Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-111-OLO0gvVCMXeT9Amo7HrzuQ-1; Thu, 07 May 2020 14:53:34 -0400 X-MC-Unique: OLO0gvVCMXeT9Amo7HrzuQ-1 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 0506920A8B; Thu, 7 May 2020 18:46:14 +0000 (UTC) Date: Thu, 7 May 2020 13:50:41 -0500 From: "Gustavo A. R. Silva" To: Paul Moore , Eric Paris Subject: [PATCH] audit: Replace zero-length array with flexible-array Message-ID: <20200507185041.GA13930@embeddedor> MIME-Version: 1.0 User-Agent: Mutt/1.9.4 (2018-02-28) X-Mimecast-Spam-Signature: yes X-Scanned-By: MIMEDefang 2.78 on 10.11.54.6 X-MIME-Autoconverted: from quoted-printable to 8bit by lists01.pubmisc.prod.ext.phx2.redhat.com id 047IrfcG016437 X-loop: linux-audit@redhat.com X-Mailman-Approved-At: Thu, 07 May 2020 15:09:42 -0400 Cc: linux-audit@redhat.com, linux-kernel@vger.kernel.org X-BeenThere: linux-audit@redhat.com X-Mailman-Version: 2.1.12 Precedence: junk List-Id: Linux Audit Discussion List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: linux-audit-bounces@redhat.com Errors-To: linux-audit-bounces@redhat.com X-Scanned-By: MIMEDefang 2.79 on 10.5.11.13 X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Content-Disposition: inline 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/linux/audit.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/include/linux/audit.h b/include/linux/audit.h index f9ceae57ca8d..2b63aee6e9fa 100644 --- a/include/linux/audit.h +++ b/include/linux/audit.h @@ -19,7 +19,7 @@ struct audit_sig_info { uid_t uid; pid_t pid; - char ctx[0]; + char ctx[]; }; struct audit_buffer; -- Linux-audit mailing list Linux-audit@redhat.com https://www.redhat.com/mailman/listinfo/linux-audit