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=-6.9 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 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 02181C33CAF for ; Thu, 23 Jan 2020 19:44:43 +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 C57DC21D7D for ; Thu, 23 Jan 2020 19:44:42 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="OEJylLAr" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org C57DC21D7D 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]:60456 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1iuiPB-0007xP-To for qemu-devel@archiver.kernel.org; Thu, 23 Jan 2020 14:44:41 -0500 Received: from eggs.gnu.org ([2001:470:142:3::10]:41264) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1iufdv-0004w2-4j for qemu-devel@nongnu.org; Thu, 23 Jan 2020 11:47:44 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1iufdt-0006WX-R0 for qemu-devel@nongnu.org; Thu, 23 Jan 2020 11:47:42 -0500 Received: from us-smtp-2.mimecast.com ([205.139.110.61]:52220 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 1iufdt-0006WF-O0 for qemu-devel@nongnu.org; Thu, 23 Jan 2020 11:47:41 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1579798061; 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=ql3iZhOCDYYWCFp4jJc0tlyutsrGTcwOVUXiZ06+mF4=; b=OEJylLArAAyARZWQjTG7Mw2P0zyEsMLc1W5CNwCNTi/sMm+AVtqJVAlRZtswwSm3yS+VVX xnkdlsYWMvwuMzUvBv4sp4APQe2LNQbLvy37L66zgCTLHc3T9YvcIqrjvmr7bwlf4f5qU0 F9HhrKM7qEYMloqHt7RW1Y5RTD+EMA8= 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-380-4n2jWFx6PAKY29oxGfpgDQ-1; Thu, 23 Jan 2020 11:47:38 -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 7ACB519057CF for ; Thu, 23 Jan 2020 16:47:37 +0000 (UTC) Received: from dgilbert-t580.localhost (ovpn-116-110.ams2.redhat.com [10.36.116.110]) by smtp.corp.redhat.com (Postfix) with ESMTP id C976E28998; Thu, 23 Jan 2020 16:47:36 +0000 (UTC) From: "Dr. David Alan Gilbert (git)" To: qemu-devel@nongnu.org, stefanha@redhat.com Subject: [PULL 040/108] virtiofsd: validate path components Date: Thu, 23 Jan 2020 16:45:22 +0000 Message-Id: <20200123164630.91498-41-dgilbert@redhat.com> In-Reply-To: <20200123164630.91498-1-dgilbert@redhat.com> References: <20200123164630.91498-1-dgilbert@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.84 on 10.5.11.23 X-MC-Unique: 4n2jWFx6PAKY29oxGfpgDQ-1 X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] 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 Reviewed-by: Daniel P. Berrang=C3=A9 Signed-off-by: Dr. David Alan Gilbert --- tools/virtiofsd/passthrough_ll.c | 59 ++++++++++++++++++++++++++++---- 1 file changed, 53 insertions(+), 6 deletions(-) diff --git a/tools/virtiofsd/passthrough_ll.c b/tools/virtiofsd/passthrough= _ll.c index ac380efcb1..e375406160 100644 --- a/tools/virtiofsd/passthrough_ll.c +++ b/tools/virtiofsd/passthrough_ll.c @@ -133,6 +133,21 @@ 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) +{ + return name[0] =3D=3D '.' && + (name[1] =3D=3D '\0' || (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) +{ + if (strchr(path, '/')) { + return 0; + } + + return !is_dot_or_dotdot(path); +} =20 static struct lo_data *lo_data(fuse_req_t req) { @@ -681,6 +696,15 @@ static void lo_lookup(fuse_req_t req, fuse_ino_t paren= t, const char *name) parent, name); } =20 + /* + * Don't use is_safe_path_component(), allow "." and ".." for NFS expo= rt + * support. + */ + if (strchr(name, '/')) { + fuse_reply_err(req, EINVAL); + return; + } + err =3D lo_do_lookup(req, parent, name, &e); if (err) { fuse_reply_err(req, err); @@ -762,6 +786,11 @@ static void lo_mknod_symlink(fuse_req_t req, fuse_ino_= t parent, struct fuse_entry_param e; struct lo_cred old =3D {}; =20 + if (!is_safe_path_component(name)) { + fuse_reply_err(req, EINVAL); + return; + } + dir =3D lo_inode(req, parent); if (!dir) { fuse_reply_err(req, EBADF); @@ -863,6 +892,11 @@ static void lo_link(fuse_req_t req, fuse_ino_t ino, fu= se_ino_t parent, struct fuse_entry_param e; int saverr; =20 + if (!is_safe_path_component(name)) { + fuse_reply_err(req, EINVAL); + return; + } + inode =3D lo_inode(req, ino); if (!inode) { fuse_reply_err(req, EBADF); @@ -904,6 +938,10 @@ out_err: static void lo_rmdir(fuse_req_t req, fuse_ino_t parent, const char *name) { int res; + if (!is_safe_path_component(name)) { + fuse_reply_err(req, EINVAL); + return; + } =20 res =3D unlinkat(lo_fd(req, parent), name, AT_REMOVEDIR); =20 @@ -916,6 +954,11 @@ static void lo_rename(fuse_req_t req, fuse_ino_t paren= t, const char *name, { int res; =20 + if (!is_safe_path_component(name) || !is_safe_path_component(newname))= { + fuse_reply_err(req, EINVAL); + return; + } + if (flags) { fuse_reply_err(req, EINVAL); return; @@ -930,6 +973,11 @@ static void lo_unlink(fuse_req_t req, fuse_ino_t paren= t, const char *name) { int res; =20 + if (!is_safe_path_component(name)) { + fuse_reply_err(req, EINVAL); + return; + } + res =3D unlinkat(lo_fd(req, parent), name, 0); =20 fuse_reply_err(req, res =3D=3D -1 ? errno : 0); @@ -1093,12 +1141,6 @@ out_err: fuse_reply_err(req, error); } =20 -static int is_dot_or_dotdot(const char *name) -{ - return name[0] =3D=3D '.' && - (name[1] =3D=3D '\0' || (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, off_t offset, struct fuse_file_info *fi, int plu= s) { @@ -1248,6 +1290,11 @@ static void lo_create(fuse_req_t req, fuse_ino_t par= ent, const char *name, parent, name); } =20 + if (!is_safe_path_component(name)) { + fuse_reply_err(req, EINVAL); + return; + } + err =3D lo_change_cred(req, &old); if (err) { goto out; --=20 2.24.1