Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S964863AbcK3JyF (ORCPT ); Wed, 30 Nov 2016 04:54:05 -0500 Received: from mail.linuxfoundation.org ([140.211.169.12]:33110 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932276AbcK3Jc1 (ORCPT ); Wed, 30 Nov 2016 04:32:27 -0500 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Dave Hansen , Pawel Lebioda , Dan Williams Subject: [PATCH 4.8 32/37] device-dax: fail all private mapping attempts Date: Wed, 30 Nov 2016 10:30:09 +0100 Message-Id: <20161130092731.190764507@linuxfoundation.org> X-Mailer: git-send-email 2.10.2 In-Reply-To: <20161130092729.623248210@linuxfoundation.org> References: <20161130092729.623248210@linuxfoundation.org> User-Agent: quilt/0.65 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1412 Lines: 38 4.8-stable review patch. If anyone has any objections, please let me know. ------------------ From: Dan Williams commit 4cb19355ea19995941ccaad115dbfac6b75215ca upstream. The device-dax implementation originally tried to be tricky and allow private read-only mappings, but in the process allowed writable MAP_PRIVATE + MAP_NORESERVE mappings. For simplicity and predictability just fail all private mapping attempts since device-dax memory is statically allocated and will never support overcommit. Cc: Dave Hansen Fixes: dee410792419 ("/dev/dax, core: file operations and dax-mmap") Reported-by: Pawel Lebioda Signed-off-by: Dan Williams Signed-off-by: Greg Kroah-Hartman --- drivers/dax/dax.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) --- a/drivers/dax/dax.c +++ b/drivers/dax/dax.c @@ -323,8 +323,8 @@ static int check_vma(struct dax_dev *dax if (!dax_dev->alive) return -ENXIO; - /* prevent private / writable mappings from being established */ - if ((vma->vm_flags & (VM_NORESERVE|VM_SHARED|VM_WRITE)) == VM_WRITE) { + /* prevent private mappings from being established */ + if ((vma->vm_flags & VM_SHARED) != VM_SHARED) { dev_info(dev, "%s: %s: fail, attempted private mapping\n", current->comm, func); return -EINVAL;