From patchwork Fri May 14 21:52:09 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: "Gustavo A. R. Silva" X-Patchwork-Id: 438979 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=-16.7 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED, DKIM_VALID, DKIM_VALID_AU, INCLUDES_CR_TRAILER, INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS 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 A3FE9C43461 for ; Fri, 14 May 2021 21:51:35 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 819A8613CD for ; Fri, 14 May 2021 21:51:35 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233286AbhENVwp (ORCPT ); Fri, 14 May 2021 17:52:45 -0400 Received: from mail.kernel.org ([198.145.29.99]:35476 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230247AbhENVwo (ORCPT ); Fri, 14 May 2021 17:52:44 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 72BDF6145B; Fri, 14 May 2021 21:51:31 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1621029092; bh=UrQTKq6eDOpcEy53oylkG4Jq2Q9f5+I8Yceo4M4Zl+M=; h=Date:From:To:Cc:Subject:From; b=SCqmCHInnTLr81xmiVlFOGuH47epGHjG1lm1r9D1PR+yEk+H/cluUocXu7FzsJqVf GAfNUjLvLYr9GsuZBFCxGkh7ZcksKfP/aH1mn8posKFOd6ENFiGB1o+irdGwDfKGnR 3xkSpjquNHLr0LbSsSalxzDbaOIqn4g9CLrbQxQ6SlDOt9CXPROxS9r6/Nb6uEEs5a 9J2J6DxFqUoEr1myamupT6HdhQjT38XgsTd57RvnRSsGr0tXF4lkFFpfXov5nYR4Uq nTYKF0F0XYDreFWEMZsvAY3NuWN1gP/YrEMoll8XduxJe/AWugdQOA1M1veLdObnH8 DBsE12z8EVbvg== Date: Fri, 14 May 2021 16:52:09 -0500 From: "Gustavo A. R. Silva" To: Ilya Dryomov , Jeff Layton , "David S. Miller" , Jakub Kicinski Cc: ceph-devel@vger.kernel.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org, "Gustavo A. R. Silva" , linux-hardening@vger.kernel.org Subject: [PATCH][next] ceph: Replace zero-length array with flexible array member Message-ID: <20210514215209.GA33310@embeddedor> MIME-Version: 1.0 Content-Disposition: inline Precedence: bulk List-ID: X-Mailing-List: ceph-devel@vger.kernel.org There is a regular need in the kernel to provide a way to declare having a dynamically sized set of trailing elements in a structure. Kernel code should always use “flexible array members”[1] for these cases. The older style of one-element or zero-length arrays should no longer be used[2]. Notice that, in this case, sizeof(au->reply_buf) translates to zero, becase in the original code reply_buf is a zero-length array. Now that reply_buf is transformed into a flexible array, the mentioned line of code is now replaced by a literal 0. Also, as a safeguard, explicitly assign NULL to auth->authorizer_reply_buf, as no heap is allocated for it, therefore it should not be accessible. [1] https://en.wikipedia.org/wiki/Flexible_array_member [2] https://www.kernel.org/doc/html/v5.10/process/deprecated.html#zero-length-and-one-element-arrays Signed-off-by: Gustavo A. R. Silva --- net/ceph/auth_none.c | 4 ++-- net/ceph/auth_none.h | 2 +- 2 files changed, 3 insertions(+), 3 deletions(-) diff --git a/net/ceph/auth_none.c b/net/ceph/auth_none.c index 70e86e462250..10ee16d2cbf0 100644 --- a/net/ceph/auth_none.c +++ b/net/ceph/auth_none.c @@ -111,8 +111,8 @@ static int ceph_auth_none_create_authorizer( auth->authorizer = (struct ceph_authorizer *) au; auth->authorizer_buf = au->buf; auth->authorizer_buf_len = au->buf_len; - auth->authorizer_reply_buf = au->reply_buf; - auth->authorizer_reply_buf_len = sizeof (au->reply_buf); + auth->authorizer_reply_buf_len = 0; + auth->authorizer_reply_buf = NULL; return 0; } diff --git a/net/ceph/auth_none.h b/net/ceph/auth_none.h index 4158f064302e..3c68c0ee3dab 100644 --- a/net/ceph/auth_none.h +++ b/net/ceph/auth_none.h @@ -16,7 +16,7 @@ struct ceph_none_authorizer { struct ceph_authorizer base; char buf[128]; int buf_len; - char reply_buf[0]; + char reply_buf[]; }; struct ceph_auth_none_info {