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 67067C43603 for ; Thu, 12 Dec 2019 17:49:23 +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 369D32067C for ; Thu, 12 Dec 2019 17:49:23 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="KCR/UcyC" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 369D32067C 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]:34928 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1ifSaX-0003kN-De for qemu-devel@archiver.kernel.org; Thu, 12 Dec 2019 12:49:21 -0500 Received: from eggs.gnu.org ([2001:470:142:3::10]:39538) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1ifRXE-000851-SM for qemu-devel@nongnu.org; Thu, 12 Dec 2019 11:41:53 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1ifRXC-0005CO-ER for qemu-devel@nongnu.org; Thu, 12 Dec 2019 11:41:52 -0500 Received: from us-smtp-2.mimecast.com ([205.139.110.61]:55125 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 1ifRXC-0005BS-A4 for qemu-devel@nongnu.org; Thu, 12 Dec 2019 11:41:50 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1576168909; 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=z8yqdPTVQDekQjGPhaXS/9UYKrLqxCuFnNjgoVrw9LU=; b=KCR/UcyCOZa7JaRyjIxQ6F4+g8jFNX3X0M6E2ix1KWPgoshzvxNrMotvlpkvQaxXdL2xwq zDNSTEWPMeTYuWexFLGOf6a8vPEkFUx2Fb3dRSki65e1PmCt6Tk71rjxG8warl9iQmAGMZ uISuRphopIAEWMg4hY7rXdxMxN3/ExY= 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-96-QSRsO-2UPQ6H6QX_xbL3aA-1; Thu, 12 Dec 2019 11:41:46 -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 30DB612A7E53 for ; Thu, 12 Dec 2019 16:41:45 +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 55F9560BE1; Thu, 12 Dec 2019 16:41:44 +0000 (UTC) From: "Dr. David Alan Gilbert (git)" To: qemu-devel@nongnu.org, stefanha@redhat.com, vgoyal@redhat.com Subject: [PATCH 101/104] virtiofsd: prevent FUSE_INIT/FUSE_DESTROY races Date: Thu, 12 Dec 2019 16:39:01 +0000 Message-Id: <20191212163904.159893-102-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: QSRsO-2UPQ6H6QX_xbL3aA-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 When running with multiple threads it can be tricky to handle FUSE_INIT/FUSE_DESTROY in parallel with other request types or in parallel with themselves. Serialize FUSE_INIT and FUSE_DESTROY so that malicious clients cannot trigger race conditions. Signed-off-by: Stefan Hajnoczi --- tools/virtiofsd/fuse_i.h | 1 + tools/virtiofsd/fuse_lowlevel.c | 18 ++++++++++++++++++ 2 files changed, 19 insertions(+) diff --git a/tools/virtiofsd/fuse_i.h b/tools/virtiofsd/fuse_i.h index d0679508cd..8a4a05b319 100644 --- a/tools/virtiofsd/fuse_i.h +++ b/tools/virtiofsd/fuse_i.h @@ -61,6 +61,7 @@ struct fuse_session { struct fuse_req list; struct fuse_req interrupts; pthread_mutex_t lock; + pthread_rwlock_t init_rwlock; int got_destroy; int broken_splice_nonblock; uint64_t notify_ctr; diff --git a/tools/virtiofsd/fuse_lowlevel.c b/tools/virtiofsd/fuse_lowleve= l.c index 10f478b00c..9f01c05e3e 100644 --- a/tools/virtiofsd/fuse_lowlevel.c +++ b/tools/virtiofsd/fuse_lowlevel.c @@ -2431,6 +2431,19 @@ void fuse_session_process_buf_int(struct fuse_sessio= n *se, req->ctx.pid =3D in->pid; req->ch =3D ch ? fuse_chan_get(ch) : NULL; =20 + /* + * INIT and DESTROY requests are serialized, all other request types + * run in parallel. This prevents races between FUSE_INIT and ordinar= y + * requests, FUSE_INIT and FUSE_INIT, FUSE_INIT and FUSE_DESTROY, and + * FUSE_DESTROY and FUSE_DESTROY. + */ + if (in->opcode =3D=3D FUSE_INIT || in->opcode =3D=3D CUSE_INIT || + in->opcode =3D=3D FUSE_DESTROY) { + pthread_rwlock_wrlock(&se->init_rwlock); + } else { + pthread_rwlock_rdlock(&se->init_rwlock); + } + err =3D EIO; if (!se->got_init) { enum fuse_opcode expected; @@ -2488,10 +2501,13 @@ void fuse_session_process_buf_int(struct fuse_sessi= on *se, } else { fuse_ll_ops[in->opcode].func(req, in->nodeid, &iter); } + + pthread_rwlock_unlock(&se->init_rwlock); return; =20 reply_err: fuse_reply_err(req, err); + pthread_rwlock_unlock(&se->init_rwlock); } =20 #define LL_OPTION(n, o, v) \ @@ -2538,6 +2554,7 @@ void fuse_session_destroy(struct fuse_session *se) se->op.destroy(se->userdata); } } + pthread_rwlock_destroy(&se->init_rwlock); pthread_mutex_destroy(&se->lock); free(se->cuse_data); if (se->fd !=3D -1) { @@ -2631,6 +2648,7 @@ struct fuse_session *fuse_session_new(struct fuse_arg= s *args, list_init_req(&se->list); list_init_req(&se->interrupts); fuse_mutex_init(&se->lock); + pthread_rwlock_init(&se->init_rwlock, NULL); =20 memcpy(&se->op, op, op_size); se->owner =3D getuid(); --=20 2.23.0