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 43277C2D0DB for ; Thu, 23 Jan 2020 18:52:54 +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 1185122464 for ; Thu, 23 Jan 2020 18:52:54 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="fCg6xBnY" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 1185122464 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]:35118 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1iuhb2-0000rE-KP for qemu-devel@archiver.kernel.org; Thu, 23 Jan 2020 13:52:52 -0500 Received: from eggs.gnu.org ([2001:470:142:3::10]:41198) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1iufdm-0004mV-5u for qemu-devel@nongnu.org; Thu, 23 Jan 2020 11:47:35 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1iufdk-0006SL-SL for qemu-devel@nongnu.org; Thu, 23 Jan 2020 11:47:34 -0500 Received: from us-smtp-2.mimecast.com ([205.139.110.61]:48135 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 1iufdk-0006SE-PP for qemu-devel@nongnu.org; Thu, 23 Jan 2020 11:47:32 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1579798052; 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=MdrT4LOkC8ZKML3gWoy6Ii/nK7cw9vlWojUEEc01X4s=; b=fCg6xBnYfxSNbdbjSVRZTjW/CAGGUAt6Wsr6N3spyG/o8mk6+jnU6Asyol2Sgkkg1uPotK RLHCGtfckTI9dQoAEkGqKiKxfRXk3TNTBrwRc3XcvO9NBGXgl1bJGUdon3BjHd/KOx+gYC S/Ld49mO/OTlaPeV1pXbVixtUtXgiLM= 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-354-yedaeuUbOXy_ZHqaNh9mmA-1; Thu, 23 Jan 2020 11:47:30 -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 13C61801E6D for ; Thu, 23 Jan 2020 16:47:30 +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 5BD1828994; Thu, 23 Jan 2020 16:47:29 +0000 (UTC) From: "Dr. David Alan Gilbert (git)" To: qemu-devel@nongnu.org, stefanha@redhat.com Subject: [PULL 035/108] virtiofsd: passthrough_ll: add lo_map for ino/fh indirection Date: Thu, 23 Jan 2020 16:45:17 +0000 Message-Id: <20200123164630.91498-36-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: yedaeuUbOXy_ZHqaNh9mmA-1 X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com 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] 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 A layer of indirection is needed because passthrough_ll cannot expose pointers or file descriptor numbers to untrusted clients. Malicious clients could send invalid pointers or file descriptors in order to crash or exploit the file system daemon. lo_map provides an integer key->value mapping. This will be used for ino and fh fields in the patches that follow. Signed-off-by: Stefan Hajnoczi Reviewed-by: Masayoshi Mizuma Signed-off-by: Dr. David Alan Gilbert --- tools/virtiofsd/passthrough_ll.c | 124 +++++++++++++++++++++++++++++++ 1 file changed, 124 insertions(+) diff --git a/tools/virtiofsd/passthrough_ll.c b/tools/virtiofsd/passthrough= _ll.c index 5e061797d4..e83a976587 100644 --- a/tools/virtiofsd/passthrough_ll.c +++ b/tools/virtiofsd/passthrough_ll.c @@ -74,6 +74,21 @@ struct _uintptr_to_must_hold_fuse_ino_t_dummy_struct { }; #endif =20 +struct lo_map_elem { + union { + /* Element values will go here... */ + ssize_t freelist; + }; + bool in_use; +}; + +/* Maps FUSE fh or ino values to internal objects */ +struct lo_map { + struct lo_map_elem *elems; + size_t nelems; + ssize_t freelist; +}; + struct lo_inode { struct lo_inode *next; /* protected by lo->mutex */ struct lo_inode *prev; /* protected by lo->mutex */ @@ -130,6 +145,115 @@ static struct lo_data *lo_data(fuse_req_t req) return (struct lo_data *)fuse_req_userdata(req); } =20 +__attribute__((unused)) static void lo_map_init(struct lo_map *map) +{ + map->elems =3D NULL; + map->nelems =3D 0; + map->freelist =3D -1; +} + +__attribute__((unused)) static void lo_map_destroy(struct lo_map *map) +{ + free(map->elems); +} + +static int lo_map_grow(struct lo_map *map, size_t new_nelems) +{ + struct lo_map_elem *new_elems; + size_t i; + + if (new_nelems <=3D map->nelems) { + return 1; + } + + new_elems =3D realloc(map->elems, sizeof(map->elems[0]) * new_nelems); + if (!new_elems) { + return 0; + } + + for (i =3D map->nelems; i < new_nelems; i++) { + new_elems[i].freelist =3D i + 1; + new_elems[i].in_use =3D false; + } + new_elems[new_nelems - 1].freelist =3D -1; + + map->elems =3D new_elems; + map->freelist =3D map->nelems; + map->nelems =3D new_nelems; + return 1; +} + +__attribute__((unused)) static struct lo_map_elem * +lo_map_alloc_elem(struct lo_map *map) +{ + struct lo_map_elem *elem; + + if (map->freelist =3D=3D -1 && !lo_map_grow(map, map->nelems + 256)) { + return NULL; + } + + elem =3D &map->elems[map->freelist]; + map->freelist =3D elem->freelist; + + elem->in_use =3D true; + + return elem; +} + +__attribute__((unused)) static struct lo_map_elem * +lo_map_reserve(struct lo_map *map, size_t key) +{ + ssize_t *prev; + + if (!lo_map_grow(map, key + 1)) { + return NULL; + } + + for (prev =3D &map->freelist; *prev !=3D -1; + prev =3D &map->elems[*prev].freelist) { + if (*prev =3D=3D key) { + struct lo_map_elem *elem =3D &map->elems[key]; + + *prev =3D elem->freelist; + elem->in_use =3D true; + return elem; + } + } + return NULL; +} + +__attribute__((unused)) static struct lo_map_elem * +lo_map_get(struct lo_map *map, size_t key) +{ + if (key >=3D map->nelems) { + return NULL; + } + if (!map->elems[key].in_use) { + return NULL; + } + return &map->elems[key]; +} + +__attribute__((unused)) static void lo_map_remove(struct lo_map *map, + size_t key) +{ + struct lo_map_elem *elem; + + if (key >=3D map->nelems) { + return; + } + + elem =3D &map->elems[key]; + if (!elem->in_use) { + return; + } + + elem->in_use =3D false; + + elem->freelist =3D map->freelist; + map->freelist =3D key; +} + static struct lo_inode *lo_inode(fuse_req_t req, fuse_ino_t ino) { if (ino =3D=3D FUSE_ROOT_ID) { --=20 2.24.1