From patchwork Wed Dec 7 01:33:28 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Dan Williams X-Patchwork-Id: 9463735 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id DE8936022E for ; Wed, 7 Dec 2016 01:37:40 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id CF4D528428 for ; Wed, 7 Dec 2016 01:37:40 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id C2D032842B; Wed, 7 Dec 2016 01:37:40 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-1.9 required=2.0 tests=BAYES_00, RCVD_IN_DNSWL_NONE autolearn=ham version=3.3.1 Received: from ml01.01.org (ml01.01.org [198.145.21.10]) (using TLSv1.2 with cipher DHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.wl.linuxfoundation.org (Postfix) with ESMTPS id 2746328428 for ; Wed, 7 Dec 2016 01:37:39 +0000 (UTC) Received: from [127.0.0.1] (localhost [IPv6:::1]) by ml01.01.org (Postfix) with ESMTP id BA24681FD1; Tue, 6 Dec 2016 17:37:39 -0800 (PST) X-Original-To: linux-nvdimm@lists.01.org Delivered-To: linux-nvdimm@lists.01.org Received: from mga09.intel.com (mga09.intel.com [134.134.136.24]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ml01.01.org (Postfix) with ESMTPS id 2423081F17 for ; Tue, 6 Dec 2016 17:37:38 -0800 (PST) Received: from fmsmga003.fm.intel.com ([10.253.24.29]) by orsmga102.jf.intel.com with ESMTP; 06 Dec 2016 17:37:37 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.33,310,1477983600"; d="scan'208";a="795088351" Received: from dwillia2-desk3.jf.intel.com (HELO dwillia2-desk3.amr.corp.intel.com) ([10.54.39.14]) by FMSMGA003.fm.intel.com with ESMTP; 06 Dec 2016 17:37:37 -0800 Subject: [PATCH] device-dax: fix private mapping restriction, permit read-only From: Dan Williams To: linux-nvdimm@lists.01.org Date: Tue, 06 Dec 2016 17:33:28 -0800 Message-ID: <148107440842.10910.8233598770558303468.stgit@dwillia2-desk3.amr.corp.intel.com> User-Agent: StGit/0.17.1-9-g687f MIME-Version: 1.0 X-BeenThere: linux-nvdimm@lists.01.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: "Linux-nvdimm developer list." List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Dave Hansen , Hugh Dickins , linux-kernel@vger.kernel.org, stable@vger.kernel.org Errors-To: linux-nvdimm-bounces@lists.01.org Sender: "Linux-nvdimm" X-Virus-Scanned: ClamAV using ClamSMTP Hugh notes in response to commit 4cb19355ea19 "device-dax: fail all private mapping attempts": "I think that is more restrictive than you intended: haven't tried, but I believe it rejects a PROT_READ, MAP_SHARED, O_RDONLY fd mmap, leaving no way to mmap /dev/dax without write permission to it." Indeed it does restrict read-only mappings, switch to checking VM_MAYSHARE, not VM_SHARED. Cc: Cc: Dave Hansen Cc: Pawel Lebioda Fixes: 4cb19355ea19 ("device-dax: fail all private mapping attempts") Reported-by: Hugh Dickins Signed-off-by: Dan Williams --- drivers/dax/dax.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/dax/dax.c b/drivers/dax/dax.c index 3d94ff20fdca..286447a83dab 100644 --- a/drivers/dax/dax.c +++ b/drivers/dax/dax.c @@ -271,7 +271,7 @@ static int check_vma(struct dax_dev *dax_dev, struct vm_area_struct *vma, return -ENXIO; /* prevent private mappings from being established */ - if ((vma->vm_flags & VM_SHARED) != VM_SHARED) { + if ((vma->vm_flags & VM_MAYSHARE) != VM_MAYSHARE) { dev_info(dev, "%s: %s: fail, attempted private mapping\n", current->comm, func); return -EINVAL;