From nobody Sun May 5 11:32:13 2024 Delivered-To: importer@patchew.org Received-SPF: pass (zoho.com: domain of gnu.org designates 209.51.188.17 as permitted sender) client-ip=209.51.188.17; envelope-from=qemu-devel-bounces+importer=patchew.org@nongnu.org; helo=lists.gnu.org; Authentication-Results: mx.zohomail.com; spf=pass (zoho.com: domain of gnu.org designates 209.51.188.17 as permitted sender) smtp.mailfrom=qemu-devel-bounces+importer=patchew.org@nongnu.org; dmarc=fail(p=none dis=none) header.from=intel.com ARC-Seal: i=1; a=rsa-sha256; t=1562621495; cv=none; d=zoho.com; s=zohoarc; b=EL0Srp9V8oA38Anu3c6VsSGaSY4AnGhER/2cYf/QXzvs5ESTDWoY3rLkqkp0XyG9hdu1hpM1Dsh/ga4oBcXIGPiPhPiCGSrAf3k3OxRduwrw2U4EBBdkgqUyoFRrMFyMaPdD6SsIJ38n/uup1PAVEnvOMyFgwl3zaW1PhdPHOi8= ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=zoho.com; s=zohoarc; t=1562621495; h=Cc:Date:From:List-Subscribe:List-Post:List-Id:List-Archive:List-Help:List-Unsubscribe:Message-ID:Sender:Subject:To:ARC-Authentication-Results; bh=7paQ+3+gKckwaVx+Cd0A0d4GKAqjqbouCpX0Ilb7k6E=; b=LRZ04XFDw+YZQFIQ+Uzd+zW6jDEHEEwqznipz1LA2IxBtghWHR6u+WN0cAqTaaN1Y2y6+wipwdGw2+KCdwGjF1RSr5ig+L99xTmMSC1Nf290rbA5qERLNKSUgo0omHBLci6jqa3zufiAZdaZ/ef+1PFhWDV6PHVMQIM8Rx5fIfo= ARC-Authentication-Results: i=1; mx.zoho.com; spf=pass (zoho.com: domain of gnu.org designates 209.51.188.17 as permitted sender) smtp.mailfrom=qemu-devel-bounces+importer=patchew.org@nongnu.org; dmarc=fail header.from= (p=none dis=none) header.from= Return-Path: Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) by mx.zohomail.com with SMTPS id 1562621495795690.3671008509268; Mon, 8 Jul 2019 14:31:35 -0700 (PDT) Received: from localhost ([::1]:44810 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.86_2) (envelope-from ) id 1hkb4Z-0006lE-6P for importer@patchew.org; Mon, 08 Jul 2019 17:21:19 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:33936) by lists.gnu.org with esmtp (Exim 4.86_2) (envelope-from ) id 1hkb3B-0006FL-Vd for qemu-devel@nongnu.org; Mon, 08 Jul 2019 17:19:54 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1hkb3B-0005yo-2M for qemu-devel@nongnu.org; Mon, 08 Jul 2019 17:19:53 -0400 Received: from mga04.intel.com ([192.55.52.120]:18941) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1hkb3A-0005tP-Pe for qemu-devel@nongnu.org; Mon, 08 Jul 2019 17:19:53 -0400 Received: from fmsmga007.fm.intel.com ([10.253.24.52]) by fmsmga104.fm.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 08 Jul 2019 14:19:42 -0700 Received: from unknown (HELO fedora.zpn.intel.com.) ([10.219.4.39]) by fmsmga007.fm.intel.com with ESMTP; 08 Jul 2019 14:19:42 -0700 X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.63,468,1557212400"; d="scan'208";a="167228709" From: Julio Montes To: qemu-devel@nongnu.org Date: Mon, 8 Jul 2019 21:19:36 +0000 Message-Id: <20190708211936.8037-1-julio.montes@intel.com> X-Mailer: git-send-email 2.17.2 X-detected-operating-system: by eggs.gnu.org: Genre and OS details not recognized. X-Received-From: 192.55.52.120 Subject: [Qemu-devel] [RFC] memory-backend-file/nvdimm: support read-only files as memory-backends X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Julio Montes , pbonzini@redhat.com, philmd@redhat.com Errors-To: qemu-devel-bounces+importer=patchew.org@nongnu.org Sender: "Qemu-devel" Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Currently is not possible to use a file that is part of a read-only filesystem as memory backend for nvdimm devices, even if this is not modifi= ed in the guest. In order to improve the security of Virtual Machines that sha= re and do not modify the memory-backend-file, QEMU should support read-only memory-backeds. Use case: * Kata Containers use a memory-backed-file as read-only rootfs, and this file is used to start all the virtual machines in the node. It would be really bad if somehow a malicious container modified it. Signed-off-by: Julio Montes --- exec.c | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/exec.c b/exec.c index 50ea9c5aaa..1eb170b55a 100644 --- a/exec.c +++ b/exec.c @@ -1852,6 +1852,12 @@ static int file_ram_open(const char *path, break; } g_free(filename); + } else if (errno =3D=3D EROFS) { + fd =3D open(path, O_RDONLY); + if (fd >=3D 0) { + /* @path names an existing read-only file, use it */ + break; + } } if (errno !=3D EEXIST && errno !=3D EINTR) { error_setg_errno(errp, errno, -- 2.17.2