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=-8.1 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, 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 C30C0C2D0CE for ; Tue, 21 Jan 2020 19:50:12 +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 7C51021835 for ; Tue, 21 Jan 2020 19:50:12 +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="KMkD88jR" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 7C51021835 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]:60258 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1itzXP-0004BV-9i for qemu-devel@archiver.kernel.org; Tue, 21 Jan 2020 14:50:11 -0500 Received: from eggs.gnu.org ([2001:470:142:3::10]:35963) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1itzWf-0003bt-AV for qemu-devel@nongnu.org; Tue, 21 Jan 2020 14:49:27 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1itzWb-0006Bf-UF for qemu-devel@nongnu.org; Tue, 21 Jan 2020 14:49:23 -0500 Received: from us-smtp-delivery-1.mimecast.com ([205.139.110.120]:35020 helo=us-smtp-1.mimecast.com) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1itzWb-0006B5-A6 for qemu-devel@nongnu.org; Tue, 21 Jan 2020 14:49:21 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1579636160; 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: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=9dGgXWissZZzZ6TUPNz/ohQp7l3i67naWHhALm5enTI=; b=KMkD88jRxHCwQjutkDCBmUJwllL8OhPzKCBosFLzzVL9rc1clQ9L7/LGHtTWBpMoce0JpB SRSzMqNL5nrFuzMpb0C2SlehKho4ZZIa8AbICQ0djBRW1Dzo4P8HBxRSYasmo5uxxthXSZ H0kfwKcXUqTzVLzyJ1S2WT5ylIS72AU= 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-284-XlXBDQvvNICc721dM5CidA-1; Tue, 21 Jan 2020 14:49:16 -0500 Received: from smtp.corp.redhat.com (int-mx03.intmail.prod.int.phx2.redhat.com [10.5.11.13]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 94973800D41; Tue, 21 Jan 2020 19:49:15 +0000 (UTC) Received: from work-vm (unknown [10.36.118.32]) by smtp.corp.redhat.com (Postfix) with ESMTPS id C2788858BE; Tue, 21 Jan 2020 19:49:06 +0000 (UTC) Date: Tue, 21 Jan 2020 19:49:03 +0000 From: "Dr. David Alan Gilbert" To: Philippe =?iso-8859-1?Q?Mathieu-Daud=E9?= Subject: Re: [PATCH v2 051/109] virtiofsd: add seccomp whitelist Message-ID: <20200121194903.GQ2929@work-vm> References: <20200121122433.50803-1-dgilbert@redhat.com> <20200121122433.50803-52-dgilbert@redhat.com> MIME-Version: 1.0 In-Reply-To: User-Agent: Mutt/1.13.0 (2019-11-30) X-Scanned-By: MIMEDefang 2.79 on 10.5.11.13 X-MC-Unique: XlXBDQvvNICc721dM5CidA-1 X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=iso-8859-1 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: 205.139.110.120 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: m.mizuma@jp.fujitsu.com, berrange@redhat.com, slp@redhat.com, qemu-devel@nongnu.org, misono.tomohiro@jp.fujitsu.com, stefanha@redhat.com, vgoyal@redhat.com Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" * Philippe Mathieu-Daud=E9 (philmd@redhat.com) wrote: > On 1/21/20 1:23 PM, Dr. David Alan Gilbert (git) wrote: > > 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 > > Signed-off-by: Dr. David Alan Gilbert > > --- > > Makefile | 2 +- > > tools/virtiofsd/Makefile.objs | 5 +- > > tools/virtiofsd/passthrough_ll.c | 2 + > > tools/virtiofsd/seccomp.c | 150 ++++++++++++++++++++++++++++++= + > > tools/virtiofsd/seccomp.h | 14 +++ > > 5 files changed, 171 insertions(+), 2 deletions(-) > > create mode 100644 tools/virtiofsd/seccomp.c > > create mode 100644 tools/virtiofsd/seccomp.h > >=20 > > diff --git a/Makefile b/Makefile > > index a87e06ad93..967d59c98a 100644 > > --- a/Makefile > > +++ b/Makefile > > @@ -327,7 +327,7 @@ HELPERS-y +=3D vhost-user-gpu$(EXESUF) > > vhost-user-json-y +=3D contrib/vhost-user-gpu/50-qemu-gpu.json > > endif > > -ifdef CONFIG_LINUX > > +ifeq ($(CONFIG_LINUX)$(CONFIG_SECCOMP),yy) > > HELPERS-y +=3D virtiofsd$(EXESUF) >=20 > Something is weird here, because I got: >=20 > $ make virtiofsd > ... > CC tools/virtiofsd/seccomp.o > tools/virtiofsd/seccomp.c:14:21: fatal error: seccomp.h: No such file or > directory > #include > ^ >=20 > Indeed I don't have libseccomp installed, ./configure reported: >=20 > ... > QGA MSI support no > seccomp support no > coroutine backend ucontext > coroutine pool yes > debug stack usage no > ... >=20 > Note also: >=20 > $ make print-CONFIG_LINUX > CONFIG_LINUX=3Dy > $ make print-CONFIG_SECCOMP > CONFIG_SECCOMP=3D > $ make print-CONFIG_LIBCAP_NG > CONFIG_LIBCAP_NG=3Dy > $ make print-HELPERS-y > HELPERS-y=3Dqemu-bridge-helper The same thing happens if you uninstall mesa-libgbm-devel and do a 'make vhost-user-gpu' These ifeq's don't remove the definition of the target, they just remove it from the HELPERS-y list, so stop it being built on an unqualified 'make' but don't change the behaviour when you explicitly ask for the target. Can you try: diff --git a/Makefile b/Makefile index ba7e2e5ebc..346a981f0e 100644 --- a/Makefile +++ b/Makefile @@ -676,8 +676,9 @@ vhost-user-blk$(EXESUF): $(vhost-user-blk-obj-y) libvho= st-user.a rdmacm-mux$(EXESUF): LIBS +=3D "-libumad" rdmacm-mux$(EXESUF): $(rdmacm-mux-obj-y) $(COMMON_LDADDS) $(call LINK, $^) - -ifdef CONFIG_LINUX # relies on Linux-specific syscalls +# +# relies on Linux specific syscalls +ifeq ($(CONFIG_LINUX)$(CONFIG_SECCOMP)$(CONFIG_LIBCAP_NG),yyy) virtiofsd$(EXESUF): $(virtiofsd-obj-y) libvhost-user.a $(COMMON_LDADDS) $(call LINK, $^) endif > > vhost-user-json-y +=3D tools/virtiofsd/50-qemu-virtiofsd.json > > endif > > diff --git a/tools/virtiofsd/Makefile.objs b/tools/virtiofsd/Makefile.o= bjs > > index 45a807500d..076f667e46 100644 > > --- a/tools/virtiofsd/Makefile.objs > > +++ b/tools/virtiofsd/Makefile.objs > > @@ -5,5 +5,8 @@ virtiofsd-obj-y =3D buffer.o \ > > fuse_signals.o \ > > fuse_virtio.o \ > > helper.o \ > > - passthrough_ll.o > > + passthrough_ll.o \ > > + seccomp.o > > +seccomp.o-cflags :=3D $(SECCOMP_CFLAGS) > > +seccomp.o-libs :=3D $(SECCOMP_LIBS) > > diff --git a/tools/virtiofsd/passthrough_ll.c b/tools/virtiofsd/passthr= ough_ll.c > > index 752beb459a..8748e64f33 100644 > > --- a/tools/virtiofsd/passthrough_ll.c > > +++ b/tools/virtiofsd/passthrough_ll.c > > @@ -58,6 +58,7 @@ > > #include > > #include "passthrough_helpers.h" > > +#include "seccomp.h" > > struct lo_map_elem { > > union { > > @@ -2090,6 +2091,7 @@ static void setup_sandbox(struct lo_data *lo, str= uct fuse_session *se) > > { > > setup_namespaces(lo, se); > > setup_mounts(lo->source); > > + setup_seccomp(); > > } > > int main(int argc, char *argv[]) > > diff --git a/tools/virtiofsd/seccomp.c b/tools/virtiofsd/seccomp.c > > new file mode 100644 > > index 0000000000..2aa4d3cc66 > > --- /dev/null > > +++ b/tools/virtiofsd/seccomp.c > > @@ -0,0 +1,150 @@ > > +/* > > + * 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), > > +#ifdef __NR_clone3 > > + SCMP_SYS(clone3), > > +#endif > > + 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), > > + SCMP_SYS(setresuid), > > +#ifdef __NR_setresgid32 > > + SCMP_SYS(setresgid32), > > +#endif > > +#ifdef __NR_setresuid32 > > + SCMP_SYS(setresuid32), > > +#endif > > + 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), > > +}; > > + > > +void setup_seccomp(void) > > +{ > > + scmp_filter_ctx ctx; > > + size_t i; > > + > > +#ifdef SCMP_ACT_KILL_PROCESS > > + ctx =3D seccomp_init(SCMP_ACT_KILL_PROCESS); > > + /* Handle a newer libseccomp but an older kernel */ > > + if (!ctx && errno =3D=3D EOPNOTSUPP) { > > + ctx =3D seccomp_init(SCMP_ACT_TRAP); > > + } > > +#else > > + ctx =3D seccomp_init(SCMP_ACT_TRAP); > > +#endif > > + if (!ctx) { > > + fuse_log(FUSE_LOG_ERR, "seccomp_init() failed\n"); > > + exit(1); > > + } > > + > > + for (i =3D 0; i < G_N_ELEMENTS(syscall_whitelist); i++) { > > + if (seccomp_rule_add(ctx, SCMP_ACT_ALLOW, > > + syscall_whitelist[i], 0) !=3D 0) { > > + fuse_log(FUSE_LOG_ERR, "seccomp_rule_add syscall %d", > > + syscall_whitelist[i]); > > + exit(1); > > + } > > + } > > + > > + /* libvhost-user calls this for post-copy migration, we don't need= it */ > > + if (seccomp_rule_add(ctx, SCMP_ACT_ERRNO(ENOSYS), > > + SCMP_SYS(userfaultfd), 0) !=3D 0) { > > + fuse_log(FUSE_LOG_ERR, "seccomp_rule_add userfaultfd failed\n"= ); > > + exit(1); > > + } > > + > > + if (seccomp_load(ctx) < 0) { > > + fuse_log(FUSE_LOG_ERR, "seccomp_load() failed\n"); > > + exit(1); > > + } > > + > > + seccomp_release(ctx); > > +} > > diff --git a/tools/virtiofsd/seccomp.h b/tools/virtiofsd/seccomp.h > > new file mode 100644 > > index 0000000000..86bce72652 > > --- /dev/null > > +++ b/tools/virtiofsd/seccomp.h > > @@ -0,0 +1,14 @@ > > +/* > > + * Seccomp sandboxing for virtiofsd > > + * > > + * Copyright (C) 2019 Red Hat, Inc. > > + * > > + * SPDX-License-Identifier: GPL-2.0-or-later > > + */ > > + > > +#ifndef VIRTIOFSD_SECCOMP_H > > +#define VIRTIOFSD_SECCOMP_H > > + > > +void setup_seccomp(void); > > + > > +#endif /* VIRTIOFSD_SECCOMP_H */ > >=20 >=20 -- Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK