[PATCH 3/4] nvme: don't allow userspace to set the Host Behavior Support feature

[Christoph Hellwig <hch@lst.de>]

This feature is used to tell the controller what features are supported
by the driver.  We thus can't let userspace processes update it.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 drivers/nvme/host/ioctl.c | 14 ++++++++++++++
 1 file changed, 14 insertions(+)

diff --git a/drivers/nvme/host/ioctl.c b/drivers/nvme/host/ioctl.c
index badbc55d29350..171c983191501 100644
--- a/drivers/nvme/host/ioctl.c
+++ b/drivers/nvme/host/ioctl.c
@@ -23,6 +23,20 @@ static int nvme_cmd_allowed(struct nvme_ns *ns, struct nvme_command *c,
 		return -EINVAL;
 	}
 
+	if (!ns) {
+		switch (c->common.opcode) {
+		case nvme_admin_set_features:
+			switch (c->features.opcode) {
+			case NVME_FEAT_HOST_BEHAVIOR:
+				dev_warn_ratelimited(ns->ctrl->device,
+					"rejecting Host Behavior support update by %s\n",
+					current->comm);
+				return -EINVAL;
+			}
+			break;
+		}
+	}
+
 	/*
 	 * Allow privileged processes to pass through any other command.
 	 */
-- 
2.30.2