From 8312a1ccff1566f375191a89b9ba71b6eb48a8cd Mon Sep 17 00:00:00 2001 From: Dongli Zhang Date: Wed, 2 Apr 2025 23:29:46 -0700 Subject: [PATCH] vhost-scsi: protect vq->log_used with vq->mutex commit f591cf9fce724e5075cc67488c43c6e39e8cbe27 upstream. 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 Acked-by: Jason Wang Reviewed-by: Mike Christie Message-Id: <20250403063028.16045-2-dongli.zhang@oracle.com> Signed-off-by: Michael S. Tsirkin [ Resolved conflicts in drivers/vhost/scsi.c bacause vhost_scsi_complete_cmd_work() has been refactored. ] Signed-off-by: Xinyu Zheng Signed-off-by: Greg Kroah-Hartman --- drivers/vhost/scsi.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) diff --git a/drivers/vhost/scsi.c b/drivers/vhost/scsi.c index f9930887fdd2c..2c19fa02141dc 100644 --- a/drivers/vhost/scsi.c +++ b/drivers/vhost/scsi.c @@ -563,8 +563,10 @@ static void vhost_scsi_complete_cmd_work(struct vhost_work *work) ret = copy_to_iter(&v_rsp, sizeof(v_rsp), &iov_iter); if (likely(ret == sizeof(v_rsp))) { struct vhost_scsi_virtqueue *q; - vhost_add_used(cmd->tvc_vq, cmd->tvc_vq_desc, 0); q = container_of(cmd->tvc_vq, struct vhost_scsi_virtqueue, vq); + mutex_lock(&q->vq.mutex); + vhost_add_used(cmd->tvc_vq, cmd->tvc_vq_desc, 0); + mutex_unlock(&q->vq.mutex); vq = q - vs->vqs; __set_bit(vq, signal); } else @@ -1166,8 +1168,11 @@ 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); } -- 2.47.2