vhost/scsi: Use copy_to_iter() to send control queue response

Uses copy_to_iter() instead of __copy_to_user() in order to ensure we
support arbitrary layouts and an input buffer split across iov entries.

Fixes: 0d02dbd68c47b ("vhost/scsi: Respond to control queue operations")
Signed-off-by: Bijan Mottahedeh <bijan.mottahedeh@oracle.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

diff --git a/drivers/vhost/scsi.c b/drivers/vhost/scsi.c
index 8e10ab436d1f13bbf38c8f15dcfcb06c4fc3ab46..344684f3e2e4a85836d021f2abe0c66d30fd2160 100644 (file)
--- a/drivers/vhost/scsi.c
+++ b/drivers/vhost/scsi.c
@@ -1127,16 +1127,18 @@ vhost_scsi_send_tmf_reject(struct vhost_scsi *vs,
                           struct vhost_virtqueue *vq,
                           struct vhost_scsi_ctx *vc)
 {
-       struct virtio_scsi_ctrl_tmf_resp __user *resp;
        struct virtio_scsi_ctrl_tmf_resp rsp;
+       struct iov_iter iov_iter;
        int ret;
 
        pr_debug("%s\n", __func__);
        memset(&rsp, 0, sizeof(rsp));
        rsp.response = VIRTIO_SCSI_S_FUNCTION_REJECTED;
-       resp = vq->iov[vc->out].iov_base;
-       ret = __copy_to_user(resp, &rsp, sizeof(rsp));
-       if (!ret)
+
+       iov_iter_init(&iov_iter, READ, &vq->iov[vc->out], vc->in, sizeof(rsp));
+
+       ret = copy_to_iter(&rsp, sizeof(rsp), &iov_iter);
+       if (likely(ret == sizeof(rsp)))
                vhost_add_used_and_signal(&vs->dev, vq, vc->head, 0);
        else
                pr_err("Faulted on virtio_scsi_ctrl_tmf_resp\n");
@@ -1147,16 +1149,18 @@ vhost_scsi_send_an_resp(struct vhost_scsi *vs,
                        struct vhost_virtqueue *vq,
                        struct vhost_scsi_ctx *vc)
 {
-       struct virtio_scsi_ctrl_an_resp __user *resp;
        struct virtio_scsi_ctrl_an_resp rsp;
+       struct iov_iter iov_iter;
        int ret;
 
        pr_debug("%s\n", __func__);
        memset(&rsp, 0, sizeof(rsp));   /* event_actual = 0 */
        rsp.response = VIRTIO_SCSI_S_OK;
-       resp = vq->iov[vc->out].iov_base;
-       ret = __copy_to_user(resp, &rsp, sizeof(rsp));
-       if (!ret)
+
+       iov_iter_init(&iov_iter, READ, &vq->iov[vc->out], vc->in, sizeof(rsp));
+
+       ret = copy_to_iter(&rsp, sizeof(rsp), &iov_iter);
+       if (likely(ret == sizeof(rsp)))
                vhost_add_used_and_signal(&vs->dev, vq, vc->head, 0);
        else
                pr_err("Faulted on virtio_scsi_ctrl_an_resp\n");