From patchwork Tue Jul 23 07:57:14 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jason Wang X-Patchwork-Id: 11054083 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 000011398 for ; Tue, 23 Jul 2019 07:57:51 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id E86F0285A2 for ; Tue, 23 Jul 2019 07:57:51 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id DCFDB285A7; Tue, 23 Jul 2019 07:57:51 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-7.9 required=2.0 tests=BAYES_00,MAILING_LIST_MULTI, RCVD_IN_DNSWL_HI autolearn=ham version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 7DE06285A2 for ; Tue, 23 Jul 2019 07:57:51 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2388647AbfGWH5i (ORCPT ); Tue, 23 Jul 2019 03:57:38 -0400 Received: from mx1.redhat.com ([209.132.183.28]:49614 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2388605AbfGWH5h (ORCPT ); Tue, 23 Jul 2019 03:57:37 -0400 Received: from smtp.corp.redhat.com (int-mx03.intmail.prod.int.phx2.redhat.com [10.5.11.13]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 32F693082E51; Tue, 23 Jul 2019 07:57:37 +0000 (UTC) Received: from hp-dl380pg8-01.lab.eng.pek2.redhat.com (hp-dl380pg8-01.lab.eng.pek2.redhat.com [10.73.8.10]) by smtp.corp.redhat.com (Postfix) with ESMTP id 3256C60605; Tue, 23 Jul 2019 07:57:30 +0000 (UTC) From: Jason Wang To: mst@redhat.com, jasowang@redhat.com Cc: kvm@vger.kernel.org, virtualization@lists.linux-foundation.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH 2/6] vhost: validate MMU notifier registration Date: Tue, 23 Jul 2019 03:57:14 -0400 Message-Id: <20190723075718.6275-3-jasowang@redhat.com> In-Reply-To: <20190723075718.6275-1-jasowang@redhat.com> References: <20190723075718.6275-1-jasowang@redhat.com> X-Scanned-By: MIMEDefang 2.79 on 10.5.11.13 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.46]); Tue, 23 Jul 2019 07:57:37 +0000 (UTC) Sender: kvm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP The return value of mmu_notifier_register() is not checked in vhost_vring_set_num_addr(). This will cause an out of sync between mm and MMU notifier thus a double free. To solve this, introduce a boolean flag to track whether MMU notifier is registered and only do unregistering when it was true. Reported-and-tested-by: syzbot+e58112d71f77113ddb7b@syzkaller.appspotmail.com Fixes: 7f466032dc9e ("vhost: access vq metadata through kernel virtual address") Signed-off-by: Jason Wang --- drivers/vhost/vhost.c | 19 +++++++++++++++---- drivers/vhost/vhost.h | 1 + 2 files changed, 16 insertions(+), 4 deletions(-) diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c index 34c0d970bcbc..058191d5efad 100644 --- a/drivers/vhost/vhost.c +++ b/drivers/vhost/vhost.c @@ -630,6 +630,7 @@ void vhost_dev_init(struct vhost_dev *dev, dev->iov_limit = iov_limit; dev->weight = weight; dev->byte_weight = byte_weight; + dev->has_notifier = false; init_llist_head(&dev->work_list); init_waitqueue_head(&dev->wait); INIT_LIST_HEAD(&dev->read_list); @@ -731,6 +732,7 @@ long vhost_dev_set_owner(struct vhost_dev *dev) if (err) goto err_mmu_notifier; #endif + dev->has_notifier = true; return 0; @@ -960,7 +962,11 @@ void vhost_dev_cleanup(struct vhost_dev *dev) } if (dev->mm) { #if VHOST_ARCH_CAN_ACCEL_UACCESS - mmu_notifier_unregister(&dev->mmu_notifier, dev->mm); + if (dev->has_notifier) { + mmu_notifier_unregister(&dev->mmu_notifier, + dev->mm); + dev->has_notifier = false; + } #endif mmput(dev->mm); } @@ -2065,8 +2071,10 @@ static long vhost_vring_set_num_addr(struct vhost_dev *d, /* Unregister MMU notifer to allow invalidation callback * can access vq->uaddrs[] without holding a lock. */ - if (d->mm) + if (d->has_notifier) { mmu_notifier_unregister(&d->mmu_notifier, d->mm); + d->has_notifier = false; + } vhost_uninit_vq_maps(vq); #endif @@ -2086,8 +2094,11 @@ static long vhost_vring_set_num_addr(struct vhost_dev *d, if (r == 0) vhost_setup_vq_uaddr(vq); - if (d->mm) - mmu_notifier_register(&d->mmu_notifier, d->mm); + if (d->mm) { + r = mmu_notifier_register(&d->mmu_notifier, d->mm); + if (!r) + d->has_notifier = true; + } #endif mutex_unlock(&vq->mutex); diff --git a/drivers/vhost/vhost.h b/drivers/vhost/vhost.h index 819296332913..a62f56a4cf72 100644 --- a/drivers/vhost/vhost.h +++ b/drivers/vhost/vhost.h @@ -214,6 +214,7 @@ struct vhost_dev { int iov_limit; int weight; int byte_weight; + bool has_notifier; }; bool vhost_exceeds_weight(struct vhost_virtqueue *vq, int pkts, int total_len);