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=-5.1 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS,USER_AGENT_SANE_1 autolearn=no 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 07C66C433DF for ; Thu, 27 Aug 2020 18:41:19 +0000 (UTC) Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id B82462073A for ; Thu, 27 Aug 2020 18:41:18 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="YluiMMBZ" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org B82462073A Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Received: from localhost ([::1]:33618 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1kBMpq-0007mD-1p for qemu-devel@archiver.kernel.org; Thu, 27 Aug 2020 14:41:18 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:49644) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1kBMp3-0007C5-K5 for qemu-devel@nongnu.org; Thu, 27 Aug 2020 14:40:29 -0400 Received: from us-smtp-delivery-1.mimecast.com ([205.139.110.120]:45446 helo=us-smtp-1.mimecast.com) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_CBC_SHA1:256) (Exim 4.90_1) (envelope-from ) id 1kBMp1-0002rx-5G for qemu-devel@nongnu.org; Thu, 27 Aug 2020 14:40:28 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1598553625; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=PbBwcjAq5BmuJef5unLPjNpqAAzb+5rg0e7HEsBL02U=; b=YluiMMBZ5mKRNv8rzqrEs1PLXAHSQiimNOixpWHlyNb/TeMHRTT+URj9nL8X3GYXpISKXw oQjkIH2cTPT2EBusuMQP9Ln750L88gI/BdBPED0g/T47aq7rtWHKJFGZK9yYRzdTIjAIyo kKwTrthsJspV6/PfQlAfRZPH/x+1uig= 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-418-jshoRrNRPVia0IufJYrYmQ-1; Thu, 27 Aug 2020 14:40:23 -0400 X-MC-Unique: jshoRrNRPVia0IufJYrYmQ-1 Received: from smtp.corp.redhat.com (int-mx08.intmail.prod.int.phx2.redhat.com [10.5.11.23]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id AD839189E616 for ; Thu, 27 Aug 2020 18:40:22 +0000 (UTC) Received: from work-vm (ovpn-114-163.ams2.redhat.com [10.36.114.163]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 58CC9196F3; Thu, 27 Aug 2020 18:40:15 +0000 (UTC) Date: Thu, 27 Aug 2020 19:40:13 +0100 From: "Dr. David Alan Gilbert" To: Stefan Hajnoczi Subject: Re: [PATCH v2 0/3] virtiofsd: allow virtiofsd to run in a container Message-ID: <20200827184013.GG2837@work-vm> References: <20200727190223.422280-1-stefanha@redhat.com> MIME-Version: 1.0 In-Reply-To: <20200727190223.422280-1-stefanha@redhat.com> User-Agent: Mutt/1.14.6 (2020-07-11) X-Scanned-By: MIMEDefang 2.84 on 10.5.11.23 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=dgilbert@redhat.com X-Mimecast-Spam-Score: 0.001 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Received-SPF: pass client-ip=205.139.110.120; envelope-from=dgilbert@redhat.com; helo=us-smtp-1.mimecast.com X-detected-operating-system: by eggs.gnu.org: First seen = 2020/08/27 00:13:19 X-ACL-Warn: Detected OS = Linux 2.2.x-3.x [generic] [fuzzy] X-Spam_score_int: -30 X-Spam_score: -3.1 X-Spam_bar: --- X-Spam_report: (-3.1 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.959, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, RCVD_IN_MSPIKE_H2=-0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action 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: vromanso@redhat.com, Daniel Walsh , qemu-devel@nongnu.org, rmohr@redhat.com, virtio-fs@redhat.com, mpatel@redhat.com, vgoyal@redhat.com Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" * Stefan Hajnoczi (stefanha@redhat.com) wrote: > v2: > * Update virtiofsd.rst documentation on sandboxing modes > * Change syntax to -o sandbox=namespace|chroot > * Add comment explaining that unshare(CLONE_FS) has no visible side-effect > while single-threaded > * xfstests and pjdfstest pass. Did not run tests on overlayfs because required > xattrs do not work without CAP_SYS_ADMIN. > > Mrunal and Dan: This patch series adds a sandboxing mode where virtiofsd relies > on the container runtime for isolation. It only does > chroot("path/to/shared-dir"), seccomp, and drops Linux capabilities. Previously > it created a new mount, pid, and net namespace but cannot do this without > CAP_SYS_ADMIN when run inside a container. pivot_root("path/to/shared-dir") has > been replaced with chroot("path/to/shared-dir"), again because CAP_SYS_ADMIN is > unavailable. The point of the chroot() is to prevent escapes from the shared > directory during path traversal. Does this ring any alarm bells or does it > sound sane? > > Container runtimes handle namespace setup and remove privileges needed by > virtiofsd to perform sandboxing. Luckily the container environment already > provides most of the sandbox that virtiofsd needs for security. > > Introduce a new "virtiofsd -o sandbox=chroot" option that uses chroot(2) > instead of namespaces. This option allows virtiofsd to work inside a container. > > Please see the individual patches for details on the changes and security > implications. > > Given that people are starting to attempt running virtiofsd in containers I > think this should go into QEMU 5.1. I've queued 1 and 3; waiting for someone with better knowledge of chroot to review 2. Dave > Stefan Hajnoczi (3): > virtiofsd: drop CAP_DAC_READ_SEARCH > virtiofsd: add container-friendly -o sandbox=chroot option > virtiofsd: probe unshare(CLONE_FS) and print an error > > tools/virtiofsd/fuse_virtio.c | 16 +++++++++ > tools/virtiofsd/helper.c | 8 +++++ > tools/virtiofsd/passthrough_ll.c | 58 ++++++++++++++++++++++++++++++-- > docs/tools/virtiofsd.rst | 32 ++++++++++++++---- > 4 files changed, 104 insertions(+), 10 deletions(-) > > -- > 2.26.2 > -- Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK From mboxrd@z Thu Jan 1 00:00:00 1970 Date: Thu, 27 Aug 2020 19:40:13 +0100 From: "Dr. David Alan Gilbert" Message-ID: <20200827184013.GG2837@work-vm> References: <20200727190223.422280-1-stefanha@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200727190223.422280-1-stefanha@redhat.com> Subject: Re: [Virtio-fs] [PATCH v2 0/3] virtiofsd: allow virtiofsd to run in a container List-Id: Development discussions about virtio-fs List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Stefan Hajnoczi Cc: vromanso@redhat.com, qemu-devel@nongnu.org, rmohr@redhat.com, virtio-fs@redhat.com, mpatel@redhat.com, vgoyal@redhat.com * Stefan Hajnoczi (stefanha@redhat.com) wrote: > v2: > * Update virtiofsd.rst documentation on sandboxing modes > * Change syntax to -o sandbox=namespace|chroot > * Add comment explaining that unshare(CLONE_FS) has no visible side-effect > while single-threaded > * xfstests and pjdfstest pass. Did not run tests on overlayfs because required > xattrs do not work without CAP_SYS_ADMIN. > > Mrunal and Dan: This patch series adds a sandboxing mode where virtiofsd relies > on the container runtime for isolation. It only does > chroot("path/to/shared-dir"), seccomp, and drops Linux capabilities. Previously > it created a new mount, pid, and net namespace but cannot do this without > CAP_SYS_ADMIN when run inside a container. pivot_root("path/to/shared-dir") has > been replaced with chroot("path/to/shared-dir"), again because CAP_SYS_ADMIN is > unavailable. The point of the chroot() is to prevent escapes from the shared > directory during path traversal. Does this ring any alarm bells or does it > sound sane? > > Container runtimes handle namespace setup and remove privileges needed by > virtiofsd to perform sandboxing. Luckily the container environment already > provides most of the sandbox that virtiofsd needs for security. > > Introduce a new "virtiofsd -o sandbox=chroot" option that uses chroot(2) > instead of namespaces. This option allows virtiofsd to work inside a container. > > Please see the individual patches for details on the changes and security > implications. > > Given that people are starting to attempt running virtiofsd in containers I > think this should go into QEMU 5.1. I've queued 1 and 3; waiting for someone with better knowledge of chroot to review 2. Dave > Stefan Hajnoczi (3): > virtiofsd: drop CAP_DAC_READ_SEARCH > virtiofsd: add container-friendly -o sandbox=chroot option > virtiofsd: probe unshare(CLONE_FS) and print an error > > tools/virtiofsd/fuse_virtio.c | 16 +++++++++ > tools/virtiofsd/helper.c | 8 +++++ > tools/virtiofsd/passthrough_ll.c | 58 ++++++++++++++++++++++++++++++-- > docs/tools/virtiofsd.rst | 32 ++++++++++++++---- > 4 files changed, 104 insertions(+), 10 deletions(-) > > -- > 2.26.2 > -- Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK