From patchwork Thu Dec 12 16:37:53 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Dr. David Alan Gilbert" X-Patchwork-Id: 11288677 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id A3170112B for ; Thu, 12 Dec 2019 17:06:19 +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 79B78214AF for ; Thu, 12 Dec 2019 17:06:19 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="P//gKzGF" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 79B78214AF 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+patchwork-qemu-devel=patchwork.kernel.org@nongnu.org Received: from localhost ([::1]:34424 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1ifRus-0001sV-Do for patchwork-qemu-devel@patchwork.kernel.org; Thu, 12 Dec 2019 12:06:18 -0500 Received: from eggs.gnu.org ([2001:470:142:3::10]:48198) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1ifRVU-0005d7-4T for qemu-devel@nongnu.org; Thu, 12 Dec 2019 11:40:06 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1ifRVS-0001u7-RB for qemu-devel@nongnu.org; Thu, 12 Dec 2019 11:40:03 -0500 Received: from us-smtp-delivery-1.mimecast.com ([207.211.31.120]:22351 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 1ifRVS-0001tE-N3 for qemu-devel@nongnu.org; Thu, 12 Dec 2019 11:40:02 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1576168802; 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=LUc9A04WxAwderv2hi4N2/3RQtBzmJtTPcK/JP0dPA0=; b=P//gKzGFVUASE/z26wb5W8bn4dzr9sRZsZKZe4gwfI10ZNHMqEA7dlWG0hPEPd466B+Scl kD7DJlsTTPIknPkG/KTaoO7241Z+HlcurL8aIbfqjVE4XKDWjIZ+z+OnszDVy2Wa+HFDfX Ja3dEd/HbIlgviNmipdeg82hKRGOTlM= 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-373-s87SvoJIPIWj6dMU2eoutw-1; Thu, 12 Dec 2019 11:40:01 -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 21A1B64A7F for ; Thu, 12 Dec 2019 16:40:00 +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 477DA60BE1; Thu, 12 Dec 2019 16:39:59 +0000 (UTC) From: "Dr. David Alan Gilbert (git)" To: qemu-devel@nongnu.org, stefanha@redhat.com, vgoyal@redhat.com Subject: [PATCH 033/104] virtiofsd: passthrough_ll: add lo_map for ino/fh indirection Date: Thu, 12 Dec 2019 16:37:53 +0000 Message-Id: <20191212163904.159893-34-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: s87SvoJIPIWj6dMU2eoutw-1 X-Mimecast-Spam-Score: 0 X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] [fuzzy] X-Received-From: 207.211.31.120 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+patchwork-qemu-devel=patchwork.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 --- 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 0188cd9ad6..0a94c3e1f2 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 +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); } +__attribute__((unused)) static void lo_map_init(struct lo_map *map) +{ + map->elems = NULL; + map->nelems = 0; + map->freelist = -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 <= map->nelems) { + return 1; + } + + new_elems = realloc(map->elems, sizeof(map->elems[0]) * new_nelems); + if (!new_elems) { + return 0; + } + + for (i = map->nelems; i < new_nelems; i++) { + new_elems[i].freelist = i + 1; + new_elems[i].in_use = false; + } + new_elems[new_nelems - 1].freelist = -1; + + map->elems = new_elems; + map->freelist = map->nelems; + map->nelems = 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 == -1 && !lo_map_grow(map, map->nelems + 256)) { + return NULL; + } + + elem = &map->elems[map->freelist]; + map->freelist = elem->freelist; + + elem->in_use = 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 = &map->freelist; *prev != -1; + prev = &map->elems[*prev].freelist) { + if (*prev == key) { + struct lo_map_elem *elem = &map->elems[key]; + + *prev = elem->freelist; + elem->in_use = true; + return elem; + } + } + return NULL; +} + +__attribute__((unused)) static struct lo_map_elem * +lo_map_get(struct lo_map *map, size_t key) +{ + if (key >= 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 >= map->nelems) { + return; + } + + elem = &map->elems[key]; + if (!elem->in_use) { + return; + } + + elem->in_use = false; + + elem->freelist = map->freelist; + map->freelist = key; +} + static struct lo_inode *lo_inode(fuse_req_t req, fuse_ino_t ino) { if (ino == FUSE_ROOT_ID) {