From 9142072649d593acbd118e71f5d257bd9996ab36 Mon Sep 17 00:00:00 2001 From: eperezma Date: Fri, 19 Feb 2021 08:49:50 -0300 Subject: [PATCH 12/54] vhost: Check for valid vdev in vhost_backend_handle_iotlb_msg MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit RH-Author: eperezma Message-id: <20210219084950.2159701-1-eperezma@redhat.com> Patchwork-id: 101110 O-Subject: [RHEL-AV-8.4.0 qemu-kvm PATCH] vhost: Check for valid vdev in vhost_backend_handle_iotlb_msg Bugzilla: 1880299 RH-Acked-by: Peter Xu RH-Acked-by: Stefano Garzarella RH-Acked-by: Xiao Wang BZ: https://bugzilla.redhat.com/show_bug.cgi?id=1880299 BRANCH: rhel-av-8.4.0 UPSTREAM: Merged BREW: https://brewweb.engineering.redhat.com/brew/taskinfo?taskID=35031170 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: 020e571b8b ("vhost: rework IOTLB messaging") Signed-off-by: Eugenio Pérez Message-Id: <20210129090728.831208-1-eperezma@redhat.com> Acked-by: Jason Wang Reviewed-by: Michael S. Tsirkin Signed-off-by: Michael S. Tsirkin (cherry picked from commit 4d1ccc17f40f73313e13c84914f70ec3d40ac738) Signed-off-by: Eugenio Pérez Signed-off-by: Eduardo Lima (Etrunko) --- 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