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=-8.4 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=ham 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 58E28C33C8C for ; Mon, 6 Jan 2020 15:23:16 +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 2762120731 for ; Mon, 6 Jan 2020 15:23:16 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="XOQP6Hia" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 2762120731 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]:53422 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1ioUDq-0007zj-LQ for qemu-devel@archiver.kernel.org; Mon, 06 Jan 2020 10:23:14 -0500 Received: from eggs.gnu.org ([2001:470:142:3::10]:48854) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1ioTnw-0007k7-6z for qemu-devel@nongnu.org; Mon, 06 Jan 2020 09:56:29 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1ioTnt-0008P9-Bc for qemu-devel@nongnu.org; Mon, 06 Jan 2020 09:56:27 -0500 Received: from us-smtp-2.mimecast.com ([205.139.110.61]:22567 helo=us-smtp-delivery-1.mimecast.com) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1ioTnt-0008OH-6Y for qemu-devel@nongnu.org; Mon, 06 Jan 2020 09:56:25 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1578322584; h=from:from:reply-to:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=2+qR+pBuB64MbgvuV/4BELLkyIwDPQ0azH2qC9PmwXs=; b=XOQP6HiaIryfSqkyFORohJnLry9FY5Az0sVL+OIDAFHDveKcNcvK+ucNbQYZdZ+8Ihr1l+ OOaHu75Ht5cd+svvFjfy1Z+qAfQZYdboXMDJ2a1sT7vo0/fAQ2wZUm1YzYLM42yjUXs0tM PNJoBP9rEFqZKfALCV6fgxi+fbD18bU= 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-390-wv3WNk53OP-whbQISQLkOw-1; Mon, 06 Jan 2020 09:56:23 -0500 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 51C6C10054E3 for ; Mon, 6 Jan 2020 14:56:22 +0000 (UTC) Received: from redhat.com (unknown [10.42.16.105]) by smtp.corp.redhat.com (Postfix) with ESMTPS id D406228980; Mon, 6 Jan 2020 14:56:18 +0000 (UTC) Date: Mon, 6 Jan 2020 14:56:18 +0000 From: Daniel =?utf-8?B?UC4gQmVycmFuZ8Op?= To: "Dr. David Alan Gilbert (git)" Subject: Re: [PATCH 050/104] virtiofsd: add seccomp whitelist Message-ID: <20200106145618.GP2930416@redhat.com> References: <20191212163904.159893-1-dgilbert@redhat.com> <20191212163904.159893-51-dgilbert@redhat.com> MIME-Version: 1.0 In-Reply-To: <20191212163904.159893-51-dgilbert@redhat.com> User-Agent: Mutt/1.12.1 (2019-06-15) X-Scanned-By: MIMEDefang 2.84 on 10.5.11.23 X-MC-Unique: wv3WNk53OP-whbQISQLkOw-1 X-Mimecast-Spam-Score: 0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable Content-Disposition: inline X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] [fuzzy] X-Received-From: 205.139.110.61 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: , Reply-To: Daniel =?utf-8?B?UC4gQmVycmFuZ8Op?= Cc: qemu-devel@nongnu.org, stefanha@redhat.com, vgoyal@redhat.com Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On Thu, Dec 12, 2019 at 04:38:10PM +0000, Dr. David Alan Gilbert (git) wrot= e: > From: Stefan Hajnoczi >=20 > Only allow system calls that are needed by virtiofsd. All other system > calls cause SIGSYS to be directed at the thread and the process will > coredump. >=20 > Restricting system calls reduces the kernel attack surface and limits > what the process can do when compromised. >=20 > Signed-off-by: Stefan Hajnoczi > with additional entries by: > Signed-off-by: Ganesh Maharaj Mahalingam > Signed-off-by: Masayoshi Mizuma > Signed-off-by: Misono Tomohiro > Signed-off-by: piaojun > Signed-off-by: Vivek Goyal > Signed-off-by: Eric Ren > --- > Makefile | 2 + > tools/virtiofsd/Makefile.objs | 5 +- > tools/virtiofsd/passthrough_ll.c | 2 + > tools/virtiofsd/seccomp.c | 141 +++++++++++++++++++++++++++++++ > tools/virtiofsd/seccomp.h | 14 +++ > 5 files changed, 163 insertions(+), 1 deletion(-) > create mode 100644 tools/virtiofsd/seccomp.c > create mode 100644 tools/virtiofsd/seccomp.h >=20 > diff --git a/Makefile b/Makefile > index 8a5746d8a0..3f5d04e1f7 100644 > --- a/Makefile > +++ b/Makefile > @@ -322,8 +322,10 @@ HELPERS-y =3D > HELPERS-$(call land,$(CONFIG_SOFTMMU),$(CONFIG_LINUX)) =3D qemu-bridge-h= elper$(EXESUF) > =20 > ifdef CONFIG_LINUX > +ifdef CONFIG_SECCOMP > HELPERS-y +=3D virtiofsd$(EXESUF) > vhost-user-json-y +=3D tools/virtiofsd/50-qemu-virtiofsd.json > +endif > =20 > ifdef CONFIG_VIRGL > ifdef CONFIG_GBM > diff --git a/tools/virtiofsd/Makefile.objs b/tools/virtiofsd/Makefile.obj= s > index 67be16332c..941b19f18e 100644 > --- a/tools/virtiofsd/Makefile.objs > +++ b/tools/virtiofsd/Makefile.objs > @@ -6,5 +6,8 @@ virtiofsd-obj-y =3D buffer.o \ > fuse_signals.o \ > fuse_virtio.o \ > helper.o \ > - passthrough_ll.o > + passthrough_ll.o \ > + seccomp.o > =20 > +seccomp.o-cflags :=3D $(SECCOMP_CFLAGS) > +seccomp.o-libs :=3D $(SECCOMP_LIBS) > diff --git a/tools/virtiofsd/passthrough_ll.c b/tools/virtiofsd/passthrou= gh_ll.c > index 754ef2618b..701608c6df 100644 > --- a/tools/virtiofsd/passthrough_ll.c > +++ b/tools/virtiofsd/passthrough_ll.c > @@ -58,6 +58,7 @@ > #include > =20 > #include "passthrough_helpers.h" > +#include "seccomp.h" > =20 > #define HAVE_POSIX_FALLOCATE 1 > struct lo_map_elem { > @@ -2073,6 +2074,7 @@ static void setup_sandbox(struct lo_data *lo, struc= t fuse_session *se) > { > setup_namespaces(lo, se); > setup_mounts(lo->source); > + setup_seccomp(); > } > =20 > int main(int argc, char *argv[]) > diff --git a/tools/virtiofsd/seccomp.c b/tools/virtiofsd/seccomp.c > new file mode 100644 > index 0000000000..6359bb55bb > --- /dev/null > +++ b/tools/virtiofsd/seccomp.c > @@ -0,0 +1,141 @@ > +/* > + * Seccomp sandboxing for virtiofsd > + * > + * Copyright (C) 2019 Red Hat, Inc. > + * > + * SPDX-License-Identifier: GPL-2.0-or-later > + */ > + > +#include "seccomp.h" > +#include "fuse_i.h" > +#include "fuse_log.h" > +#include > +#include > +#include > +#include > + > +/* Bodge for libseccomp 2.4.2 which broke ppoll */ > +#if !defined(__SNR_ppoll) && defined(__SNR_brk) > +#ifdef __NR_ppoll > +#define __SNR_ppoll __NR_ppoll > +#else > +#define __SNR_ppoll __PNR_ppoll > +#endif > +#endif > + > +static const int syscall_whitelist[] =3D { > + /* TODO ireg sem*() syscalls */ > + SCMP_SYS(brk), > + SCMP_SYS(capget), /* For CAP_FSETID */ > + SCMP_SYS(capset), > + SCMP_SYS(clock_gettime), > + SCMP_SYS(clone), clone2 ? clone3 ? IIC some archs in Linux will require the newer variants. > + SCMP_SYS(close), > + SCMP_SYS(copy_file_range), > + SCMP_SYS(dup), > + SCMP_SYS(eventfd2), > + SCMP_SYS(exit), > + SCMP_SYS(exit_group), > + SCMP_SYS(fallocate), > + SCMP_SYS(fchmodat), > + SCMP_SYS(fchownat), > + SCMP_SYS(fcntl), > + SCMP_SYS(fdatasync), > + SCMP_SYS(fgetxattr), > + SCMP_SYS(flistxattr), > + SCMP_SYS(flock), > + SCMP_SYS(fremovexattr), > + SCMP_SYS(fsetxattr), > + SCMP_SYS(fstat), > + SCMP_SYS(fstatfs), > + SCMP_SYS(fsync), > + SCMP_SYS(ftruncate), > + SCMP_SYS(futex), > + SCMP_SYS(getdents), > + SCMP_SYS(getdents64), > + SCMP_SYS(getegid), > + SCMP_SYS(geteuid), > + SCMP_SYS(getpid), > + SCMP_SYS(gettid), > + SCMP_SYS(gettimeofday), > + SCMP_SYS(linkat), > + SCMP_SYS(lseek), > + SCMP_SYS(madvise), > + SCMP_SYS(mkdirat), > + SCMP_SYS(mknodat), > + SCMP_SYS(mmap), > + SCMP_SYS(mprotect), > + SCMP_SYS(mremap), > + SCMP_SYS(munmap), > + SCMP_SYS(newfstatat), > + SCMP_SYS(open), > + SCMP_SYS(openat), > + SCMP_SYS(ppoll), > + SCMP_SYS(prctl), /* TODO restrict to just PR_SET_NAME? */ > + SCMP_SYS(preadv), > + SCMP_SYS(pread64), > + SCMP_SYS(pwritev), > + SCMP_SYS(pwrite64), > + SCMP_SYS(read), > + SCMP_SYS(readlinkat), > + SCMP_SYS(recvmsg), > + SCMP_SYS(renameat), > + SCMP_SYS(renameat2), > + SCMP_SYS(rt_sigaction), > + SCMP_SYS(rt_sigprocmask), > + SCMP_SYS(rt_sigreturn), > + SCMP_SYS(sendmsg), > + SCMP_SYS(setresgid), Should be setresgid32 instead I think. We don't want the legacy syscall that's limted to 16-bit GIDs Needs the code fix I mention in an earlier patch too. > + SCMP_SYS(setresuid), Same as above > + SCMP_SYS(set_robust_list), > + SCMP_SYS(symlinkat), > + SCMP_SYS(time), /* Rarely needed, except on static builds */ > + SCMP_SYS(tgkill), > + SCMP_SYS(unlinkat), > + SCMP_SYS(utimensat), > + SCMP_SYS(write), > + SCMP_SYS(writev), > +}; Regards, Daniel --=20 |: https://berrange.com -o- https://www.flickr.com/photos/dberrange= :| |: https://libvirt.org -o- https://fstop138.berrange.com= :| |: https://entangle-photo.org -o- https://www.instagram.com/dberrange= :|