From: Bijan Mottahedeh <bijan.mottahedeh@oracle.com>
Date: Tue, 4 Dec 2018 00:48:23 +0000 (-0800)
Subject: vhost/scsi: Use copy_to_iter() to send control queue response
X-Git-Tag: v5.0-rc3~4^2
X-Git-Url: https://asedeno.scripts.mit.edu/gitweb/?a=commitdiff_plain;h=8e5dadfe76cf2862ebf3e4f22adef29982df7766;p=linux.git

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 8e10ab436d1f..344684f3e2e4 100644
--- 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");