From 4355c1abcaedd64a18d627284a3b7e54acb00714 Mon Sep 17 00:00:00 2001 From: Stefan Hajnoczi Date: Wed, 21 Sep 2016 16:52:25 +0100 Subject: [PATCH] virtio: handle virtqueue_num_heads() errors If the avail ring index is bogus virtqueue_num_heads() must return -EINVAL. The only caller is virtqueue_get_avail_bytes(). Return saying no bytes are available when virtqueue_num_heads() fails. Signed-off-by: Stefan Hajnoczi Reviewed-by: Cornelia Huck Reviewed-by: Michael S. Tsirkin Signed-off-by: Michael S. Tsirkin Reviewed-by: Cornelia Huck --- hw/virtio/virtio.c | 11 ++++++++--- 1 file changed, 8 insertions(+), 3 deletions(-) diff --git a/hw/virtio/virtio.c b/hw/virtio/virtio.c index 82142c6..b7ac356 100644 --- a/hw/virtio/virtio.c +++ b/hw/virtio/virtio.c @@ -347,9 +347,9 @@ static int virtqueue_num_heads(VirtQueue *vq, unsigned int idx) /* Check it isn't doing very strange things with descriptor numbers. */ if (num_heads > vq->vring.num) { - error_report("Guest moved used index from %u to %u", + virtio_error(vq->vdev, "Guest moved used index from %u to %u", idx, vq->shadow_avail_idx); - exit(1); + return -EINVAL; } /* On success, callers read a descriptor at vq->last_avail_idx. * Make sure descriptor read does not bypass avail index read. */ @@ -417,7 +417,7 @@ void virtqueue_get_avail_bytes(VirtQueue *vq, unsigned int *in_bytes, idx = vq->last_avail_idx; total_bufs = in_total = out_total = 0; - while (virtqueue_num_heads(vq, idx)) { + while ((rc = virtqueue_num_heads(vq, idx)) > 0) { VirtIODevice *vdev = vq->vdev; unsigned int max, num_bufs, indirect = 0; VRingDesc desc; @@ -478,6 +478,11 @@ void virtqueue_get_avail_bytes(VirtQueue *vq, unsigned int *in_bytes, else total_bufs++; } + + if (rc < 0) { + goto err; + } + done: if (in_bytes) { *in_bytes = in_total; -- 2.7.4