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[PATCH] vhost: Check for valid vdev in vhost_backend_handle_iotlb_msg
From: |
Eugenio Pérez |
Subject: |
[PATCH] vhost: Check for valid vdev in vhost_backend_handle_iotlb_msg |
Date: |
Fri, 29 Jan 2021 10:07:28 +0100 |
Not checking this can lead to invalid dev->vdev member access in
vhost_device_iotlb_miss if backend issue an iotlb message in a bad
timing, either maliciously or by a bug.
Reproduced rebooting a guest with testpmd in txonly forward mode.
#0 0x0000559ffff94394 in vhost_device_iotlb_miss (
dev=dev@entry=0x55a0012f6680, iova=10245279744, write=1)
at ../hw/virtio/vhost.c:1013
#1 0x0000559ffff9ac31 in vhost_backend_handle_iotlb_msg (
imsg=0x7ffddcfd32c0, dev=0x55a0012f6680)
at ../hw/virtio/vhost-backend.c:411
#2 vhost_backend_handle_iotlb_msg (dev=dev@entry=0x55a0012f6680,
imsg=imsg@entry=0x7ffddcfd32c0)
at ../hw/virtio/vhost-backend.c:404
#3 0x0000559fffeded7b in slave_read (opaque=0x55a0012f6680)
at ../hw/virtio/vhost-user.c:1464
#4 0x000055a0000c541b in aio_dispatch_handler (
ctx=ctx@entry=0x55a0010a2120, node=0x55a0012d9e00)
at ../util/aio-posix.c:329
Fixes: 6dcdd06e3b ("spec/vhost-user spec: Add IOMMU support")
Signed-off-by: Eugenio Pérez <eperezma@redhat.com>
---
hw/virtio/vhost-backend.c | 5 +++++
1 file changed, 5 insertions(+)
diff --git a/hw/virtio/vhost-backend.c b/hw/virtio/vhost-backend.c
index 222bbcc62d..31b33bde37 100644
--- a/hw/virtio/vhost-backend.c
+++ b/hw/virtio/vhost-backend.c
@@ -406,6 +406,11 @@ int vhost_backend_handle_iotlb_msg(struct vhost_dev *dev,
{
int ret = 0;
+ if (unlikely(!dev->vdev)) {
+ error_report("Unexpected IOTLB message when virtio device is stopped");
+ return -EINVAL;
+ }
+
switch (imsg->type) {
case VHOST_IOTLB_MISS:
ret = vhost_device_iotlb_miss(dev, imsg->iova,
--
2.27.0
- [PATCH] vhost: Check for valid vdev in vhost_backend_handle_iotlb_msg,
Eugenio Pérez <=