From: Dongli Zhang dongli.zhang@oracle.com
[ Upstream commit f591cf9fce724e5075cc67488c43c6e39e8cbe27 ]
The vhost-scsi completion path may access vq->log_base when vq->log_used is already set to false.
vhost-thread QEMU-thread
vhost_scsi_complete_cmd_work() -> vhost_add_used() -> vhost_add_used_n() if (unlikely(vq->log_used)) QEMU disables vq->log_used via VHOST_SET_VRING_ADDR. mutex_lock(&vq->mutex); vq->log_used = false now! mutex_unlock(&vq->mutex);
QEMU gfree(vq->log_base) log_used() -> log_write(vq->log_base)
Assuming the VMM is QEMU. The vq->log_base is from QEMU userpace and can be reclaimed via gfree(). As a result, this causes invalid memory writes to QEMU userspace.
The control queue path has the same issue.
Signed-off-by: Dongli Zhang dongli.zhang@oracle.com Acked-by: Jason Wang jasowang@redhat.com Reviewed-by: Mike Christie michael.christie@oracle.com Message-Id: 20250403063028.16045-2-dongli.zhang@oracle.com Signed-off-by: Michael S. Tsirkin mst@redhat.com Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/vhost/scsi.c | 8 ++++++++ 1 file changed, 8 insertions(+)
diff --git a/drivers/vhost/scsi.c b/drivers/vhost/scsi.c index 7aeff435c1d87..a71ad7353341e 100644 --- a/drivers/vhost/scsi.c +++ b/drivers/vhost/scsi.c @@ -571,6 +571,9 @@ static void vhost_scsi_complete_cmd_work(struct vhost_work *work) int ret;
llnode = llist_del_all(&svq->completion_list); + + mutex_lock(&svq->vq.mutex); + llist_for_each_entry_safe(cmd, t, llnode, tvc_completion_list) { se_cmd = &cmd->tvc_se_cmd;
@@ -604,6 +607,8 @@ static void vhost_scsi_complete_cmd_work(struct vhost_work *work) vhost_scsi_release_cmd_res(se_cmd); }
+ mutex_unlock(&svq->vq.mutex); + if (signal) vhost_signal(&svq->vs->dev, &svq->vq); } @@ -1297,8 +1302,11 @@ static void vhost_scsi_tmf_resp_work(struct vhost_work *work) else resp_code = VIRTIO_SCSI_S_FUNCTION_REJECTED;
+ mutex_lock(&tmf->svq->vq.mutex); vhost_scsi_send_tmf_resp(tmf->vhost, &tmf->svq->vq, tmf->in_iovs, tmf->vq_desc, &tmf->resp_iov, resp_code); + mutex_unlock(&tmf->svq->vq.mutex); + vhost_scsi_release_tmf_res(tmf); }