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 CF34DC43603 for ; Thu, 12 Dec 2019 17:21:12 +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 9F44D205C9 for ; Thu, 12 Dec 2019 17:21:12 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="FtppkQ6+" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 9F44D205C9 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]:34580 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1ifS9H-0001T4-8s for qemu-devel@archiver.kernel.org; Thu, 12 Dec 2019 12:21:11 -0500 Received: from eggs.gnu.org ([2001:470:142:3::10]:50181) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1ifRVg-0005qH-MZ for qemu-devel@nongnu.org; Thu, 12 Dec 2019 11:40:18 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1ifRVf-0002E1-Ej for qemu-devel@nongnu.org; Thu, 12 Dec 2019 11:40:16 -0500 Received: from us-smtp-delivery-1.mimecast.com ([205.139.110.120]:60925 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 1ifRVf-0002BP-52 for qemu-devel@nongnu.org; Thu, 12 Dec 2019 11:40:15 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1576168813; 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=dDtoPLNQ3V8oD+vwQyOcLXH0VziNW1yt0dVfeNFT2To=; b=FtppkQ6+YxFxamPuWfxgkWVkbbaYC3kPch6jwgjG2zvg80ey0TZFWZTGappCq3P5AxBNZ0 vVB5GdbzjqibLclov/LshpffMD76hCVJsrCIdI4z4Y1VExN/lTEOZcRYVJX6PYhAPIRSeD JFspBE+vUbq+K93zidAvoUDlySX7FU0= 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-36-sdirObqENcmXeZrnGGaZSQ-1; Thu, 12 Dec 2019 11:40:11 -0500 Received: from smtp.corp.redhat.com (int-mx02.intmail.prod.int.phx2.redhat.com [10.5.11.12]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 068881005510 for ; Thu, 12 Dec 2019 16:40:11 +0000 (UTC) Received: from dgilbert-t580.localhost (ovpn-116-226.ams2.redhat.com [10.36.116.226]) by smtp.corp.redhat.com (Postfix) with ESMTP id 25DF460BE1; Thu, 12 Dec 2019 16:40:09 +0000 (UTC) From: "Dr. David Alan Gilbert (git)" To: qemu-devel@nongnu.org, stefanha@redhat.com, vgoyal@redhat.com Subject: [PATCH 038/104] virtiofsd: validate path components Date: Thu, 12 Dec 2019 16:37:58 +0000 Message-Id: <20191212163904.159893-39-dgilbert@redhat.com> In-Reply-To: <20191212163904.159893-1-dgilbert@redhat.com> References: <20191212163904.159893-1-dgilbert@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.12 X-MC-Unique: sdirObqENcmXeZrnGGaZSQ-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: 205.139.110.120 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: , 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 --- 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 1faae2753f..84e9d8916f 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); @@ -745,6 +769,11 @@ 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); @@ -846,6 +875,11 @@ 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); @@ -887,6 +921,10 @@ 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 @@ -899,6 +937,11 @@ 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; @@ -913,6 +956,11 @@ 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); @@ -1076,12 +1124,6 @@ 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) { @@ -1231,6 +1273,11 @@ 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 2.23.0