From patchwork Thu Mar 24 17:56:54 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Stefan Hajnoczi X-Patchwork-Id: 8663611 Return-Path: X-Original-To: patchwork-qemu-devel@patchwork.kernel.org Delivered-To: patchwork-parsemail@patchwork1.web.kernel.org Received: from mail.kernel.org (mail.kernel.org [198.145.29.136]) by patchwork1.web.kernel.org (Postfix) with ESMTP id 909F59F36E for ; Thu, 24 Mar 2016 18:00:40 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id 3AB0C20434 for ; Thu, 24 Mar 2016 18:00:38 +0000 (UTC) Received: from lists.gnu.org (lists.gnu.org [208.118.235.17]) (using TLSv1 with cipher AES256-SHA (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id BA8142041E for ; Thu, 24 Mar 2016 18:00:33 +0000 (UTC) Received: from localhost ([::1]:52150 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1aj9Yf-0004ZY-61 for patchwork-qemu-devel@patchwork.kernel.org; Thu, 24 Mar 2016 14:00:33 -0400 Received: from eggs.gnu.org ([2001:4830:134:3::10]:51727) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1aj9VS-000765-Qq for qemu-devel@nongnu.org; Thu, 24 Mar 2016 13:57:15 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1aj9VS-0003WX-1s for qemu-devel@nongnu.org; Thu, 24 Mar 2016 13:57:14 -0400 Received: from mx1.redhat.com ([209.132.183.28]:39776) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1aj9VR-0003W2-Th for qemu-devel@nongnu.org; Thu, 24 Mar 2016 13:57:13 -0400 Received: from int-mx09.intmail.prod.int.phx2.redhat.com (int-mx09.intmail.prod.int.phx2.redhat.com [10.5.11.22]) by mx1.redhat.com (Postfix) with ESMTPS id 7CCCC694 for ; Thu, 24 Mar 2016 17:57:13 +0000 (UTC) Received: from localhost (ovpn-112-44.ams2.redhat.com [10.36.112.44]) by int-mx09.intmail.prod.int.phx2.redhat.com (8.14.4/8.14.4) with ESMTP id u2OHvCuN023945; Thu, 24 Mar 2016 13:57:13 -0400 From: Stefan Hajnoczi To: qemu-devel@nongnu.org Date: Thu, 24 Mar 2016 17:56:54 +0000 Message-Id: <1458842214-11450-8-git-send-email-stefanha@redhat.com> In-Reply-To: <1458842214-11450-1-git-send-email-stefanha@redhat.com> References: <1458842214-11450-1-git-send-email-stefanha@redhat.com> X-Scanned-By: MIMEDefang 2.68 on 10.5.11.22 X-detected-operating-system: by eggs.gnu.org: GNU/Linux 3.x X-Received-From: 209.132.183.28 Cc: Fam Zheng , Stefan Hajnoczi , "Michael S. Tsirkin" Subject: [Qemu-devel] [RFC 7/7] virtio: handle virtqueue_get_head() errors X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.14 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-bounces+patchwork-qemu-devel=patchwork.kernel.org@nongnu.org X-Spam-Status: No, score=-6.9 required=5.0 tests=BAYES_00, RCVD_IN_DNSWL_HI, UNPARSEABLE_RELAY autolearn=unavailable version=3.3.1 X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on mail.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP Stop processing the vring if virtqueue_get_head() fetches an out-of-bounds head index. Signed-off-by: Stefan Hajnoczi --- hw/virtio/virtio.c | 26 ++++++++++++++++---------- 1 file changed, 16 insertions(+), 10 deletions(-) diff --git a/hw/virtio/virtio.c b/hw/virtio/virtio.c index 525af8b..bf234eb 100644 --- a/hw/virtio/virtio.c +++ b/hw/virtio/virtio.c @@ -333,21 +333,20 @@ static int virtqueue_num_heads(VirtQueue *vq, unsigned int idx) return num_heads; } -static unsigned int virtqueue_get_head(VirtQueue *vq, unsigned int idx) +static bool virtqueue_get_head(VirtQueue *vq, unsigned int idx, + unsigned int *head) { - unsigned int head; - /* Grab the next descriptor number they're advertising, and increment * the index we've seen. */ - head = vring_avail_ring(vq, idx % vq->vring.num); + *head = vring_avail_ring(vq, idx % vq->vring.num); /* If their number is silly, that's a fatal mistake. */ - if (head >= vq->vring.num) { - error_report("Guest says index %u is available", head); - exit(1); + if (*head >= vq->vring.num) { + virtio_error(vq->vdev, "Guest says index %u is available", *head); + return false; } - return head; + return true; } enum { @@ -399,7 +398,11 @@ void virtqueue_get_avail_bytes(VirtQueue *vq, unsigned int *in_bytes, max = vq->vring.num; num_bufs = total_bufs; - i = virtqueue_get_head(vq, idx++); + + if (!virtqueue_get_head(vq, idx++, &i)) { + goto err; + } + desc_pa = vq->vring.desc; vring_desc_read(vdev, &desc, desc_pa, i); @@ -618,11 +621,14 @@ void *virtqueue_pop(VirtQueue *vq, size_t sz) max = vq->vring.num; - i = head = virtqueue_get_head(vq, vq->last_avail_idx++); + if (!virtqueue_get_head(vq, vq->last_avail_idx++, &head)) { + return NULL; + } if (virtio_vdev_has_feature(vdev, VIRTIO_RING_F_EVENT_IDX)) { vring_set_avail_event(vq, vq->last_avail_idx); } + i = head; vring_desc_read(vdev, &desc, desc_pa, i); if (desc.flags & VRING_DESC_F_INDIRECT) { if (desc.len % sizeof(VRingDesc)) {