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=-6.8 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS 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 1BBC5CA9EAF for ; Thu, 24 Oct 2019 12:08:49 +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 D9C6620856 for ; Thu, 24 Oct 2019 12:08:48 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="MzKC4FYg" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org D9C6620856 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]:40620 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1iNbuo-0001X6-5q for qemu-devel@archiver.kernel.org; Thu, 24 Oct 2019 08:08:30 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:39281) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1iNbHZ-0002WT-Mz for qemu-devel@nongnu.org; Thu, 24 Oct 2019 07:27:58 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1iNbHY-0008Po-AI for qemu-devel@nongnu.org; Thu, 24 Oct 2019 07:27:57 -0400 Received: from us-smtp-1.mimecast.com ([205.139.110.61]:26425 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 1iNbHY-0008Pa-4Y for qemu-devel@nongnu.org; Thu, 24 Oct 2019 07:27:56 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1571916475; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=MzBHWGD/wm0Xuo70Lip4zEEYzbn0jIYX9uCmNj5m2Gw=; b=MzKC4FYgri1h9nNjJL6WQMfrC4jpKQdlqARVK1JPNvknX88a3e1vWd4Zl7FPIl2TpEd0o4 d/d0uIoi75IRRWHMgjteRKQ3VJxT37HMGXbX6mA6TvYzCAW/e6+tJ133F7NRQiD0Y77oan 1W7XgvxZvlxj7ibsNtZbG0eIyU29NbE= 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-46-ioU2VeBKNk-ZApiHt0eEtw-1; Thu, 24 Oct 2019 07:27:53 -0400 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 16586800D49; Thu, 24 Oct 2019 11:27:52 +0000 (UTC) Received: from dgilbert-t580.localhost (ovpn-117-248.ams2.redhat.com [10.36.117.248]) by smtp.corp.redhat.com (Postfix) with ESMTP id 8CCBC196B2; Thu, 24 Oct 2019 11:27:49 +0000 (UTC) From: "Dr. David Alan Gilbert (git)" To: qemu-devel@nongnu.org, renzhen@linux.alibaba.com, eguan@linux.alibaba.com, ganesh.mahalingam@intel.com, m.mizuma@jp.fujitsu.com, mszeredi@redhat.com, misono.tomohiro@jp.fujitsu.com, tao.peng@linux.alibaba.com, piaojun@huawei.com, stefanha@redhat.com, vgoyal@redhat.com, mst@redhat.com, berrange@redhat.com Subject: [PATCH 07/25] virtiofsd: validate path components Date: Thu, 24 Oct 2019 12:27:00 +0100 Message-Id: <20191024112718.34657-8-dgilbert@redhat.com> In-Reply-To: <20191024112718.34657-1-dgilbert@redhat.com> References: <20191024112718.34657-1-dgilbert@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.84 on 10.5.11.23 X-MC-Unique: ioU2VeBKNk-ZApiHt0eEtw-1 X-Mimecast-Spam-Score: 0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: quoted-printable 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: , Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" From: Stefan Hajnoczi Several FUSE requests contain single path components. A correct FUSE client sends well-formed path components but there is currently no input validation in case something went wrong or the client is malicious. Refuse ".", "..", and paths containing '/' when we expect a path component. Signed-off-by: Stefan Hajnoczi --- contrib/virtiofsd/passthrough_ll.c | 59 +++++++++++++++++++++++++++--- 1 file changed, 53 insertions(+), 6 deletions(-) diff --git a/contrib/virtiofsd/passthrough_ll.c b/contrib/virtiofsd/passthr= ough_ll.c index 9f84419816..702fedc38a 100644 --- a/contrib/virtiofsd/passthrough_ll.c +++ b/contrib/virtiofsd/passthrough_ll.c @@ -146,6 +146,21 @@ static void unref_inode(struct lo_data *lo, struct lo_= inode *inode, uint64_t n); =20 static struct lo_inode *lo_find(struct lo_data *lo, struct stat *st); =20 +static int is_dot_or_dotdot(const char *name) +{ +=09return name[0] =3D=3D '.' && (name[1] =3D=3D '\0' || +=09=09=09=09 (name[1] =3D=3D '.' && name[2] =3D=3D '\0')); +} + +/* Is `path` a single path component that is not "." or ".."? */ +static int is_safe_path_component(const char *path) +{ +=09if (strchr(path, '/')) { +=09=09return 0; +=09} + +=09return !is_dot_or_dotdot(path); +} =20 static struct lo_data *lo_data(fuse_req_t req) { @@ -657,6 +672,14 @@ static void lo_lookup(fuse_req_t req, fuse_ino_t paren= t, const char *name) =09=09fuse_log(FUSE_LOG_DEBUG, "lo_lookup(parent=3D%" PRIu64 ", name=3D%s)= \n", =09=09=09parent, name); =20 +=09/* Don't use is_safe_path_component(), allow "." and ".." for NFS expor= t +=09 * support. +=09 */ +=09if (strchr(name, '/')) { +=09=09fuse_reply_err(req, EINVAL); +=09=09return; +=09} + =09err =3D lo_do_lookup(req, parent, name, &e); =09if (err) =09=09fuse_reply_err(req, err); @@ -719,6 +742,11 @@ static void lo_mknod_symlink(fuse_req_t req, fuse_ino_= t parent, =09struct fuse_entry_param e; =09struct lo_cred old =3D {}; =20 +=09if (!is_safe_path_component(name)) { +=09=09fuse_reply_err(req, EINVAL); +=09=09return; +=09} + =09dir =3D lo_inode(req, parent); =09if (!dir) { =09=09fuse_reply_err(req, EBADF); @@ -815,6 +843,11 @@ static void lo_link(fuse_req_t req, fuse_ino_t ino, fu= se_ino_t parent, =09struct fuse_entry_param e; =09int saverr; =20 +=09if (!is_safe_path_component(name)) { +=09=09fuse_reply_err(req, EINVAL); +=09=09return; +=09} + =09inode =3D lo_inode(req, ino); =09if (!inode) { =09=09fuse_reply_err(req, EBADF); @@ -854,6 +887,10 @@ out_err: static void lo_rmdir(fuse_req_t req, fuse_ino_t parent, const char *name) { =09int res; +=09if (!is_safe_path_component(name)) { +=09=09fuse_reply_err(req, EINVAL); +=09=09return; +=09} =20 =09res =3D unlinkat(lo_fd(req, parent), name, AT_REMOVEDIR); =20 @@ -866,6 +903,12 @@ static void lo_rename(fuse_req_t req, fuse_ino_t paren= t, const char *name, { =09int res; =20 +=09if (!is_safe_path_component(name) || +=09=09!is_safe_path_component(newname)) { +=09=09fuse_reply_err(req, EINVAL); +=09=09return; +=09} + =09if (flags) { =09=09fuse_reply_err(req, EINVAL); =09=09return; @@ -881,6 +924,11 @@ static void lo_unlink(fuse_req_t req, fuse_ino_t paren= t, const char *name) { =09int res; =20 +=09if (!is_safe_path_component(name)) { +=09=09fuse_reply_err(req, EINVAL); +=09=09return; +=09} + =09res =3D unlinkat(lo_fd(req, parent), name, 0); =20 =09fuse_reply_err(req, res =3D=3D -1 ? errno : 0); @@ -1031,12 +1079,6 @@ out_err: =09fuse_reply_err(req, error); } =20 -static int is_dot_or_dotdot(const char *name) -{ -=09return name[0] =3D=3D '.' && (name[1] =3D=3D '\0' || -=09=09=09=09 (name[1] =3D=3D '.' && name[2] =3D=3D '\0')); -} - static void lo_do_readdir(fuse_req_t req, fuse_ino_t ino, size_t size, =09=09=09 off_t offset, struct fuse_file_info *fi, int plus) { @@ -1179,6 +1221,11 @@ static void lo_create(fuse_req_t req, fuse_ino_t par= ent, const char *name, =09=09fuse_log(FUSE_LOG_DEBUG, "lo_create(parent=3D%" PRIu64 ", name=3D%s)= \n", =09=09=09parent, name); =20 +=09if (!is_safe_path_component(name)) { +=09=09fuse_reply_err(req, EINVAL); +=09=09return; +=09} + =09err =3D lo_change_cred(req, &old); =09if (err) =09=09goto out; --=20 2.23.0