[PATCH 5.4 197/222] um: virtio_uml: Disallow modular build

Greg Kroah-Hartman
2020-01-22T13:26:57Z

From: Johannes Berg <johannes.berg@intel.com>

commit bf9f80cf0ccab5f346f7d3cdc445da8fcfe6ce34 upstream.

This driver *can* be a module, but then its parameters (socket path)
are untrusted data from inside the VM, and that isn't allowed. Allow
the code to only be built-in to avoid that.

Fixes: 5d38f324993f ("um: drivers: Add virtio vhost-user driver")
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Acked-by: Anton Ivanov <anton.ivanov@cambridgegreys.co.uk>
Signed-off-by: Richard Weinberger <richard@nod.at>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
arch/um/drivers/Kconfig | 2 +-
arch/um/drivers/virtio_uml.c | 4 ++--
2 files changed, 3 insertions(+), 3 deletions(-)

--- a/arch/um/drivers/Kconfig
+++ b/arch/um/drivers/Kconfig
@@ -337,7 +337,7 @@ config UML_NET_SLIRP
endmenu

config VIRTIO_UML
- tristate "UML driver for virtio devices"
+ bool "UML driver for virtio devices"
select VIRTIO
help
This driver provides support for virtio based paravirtual device
--- a/arch/um/drivers/virtio_uml.c
+++ b/arch/um/drivers/virtio_uml.c
@@ -4,12 +4,12 @@
*
* Copyright(c) 2019 Intel Corporation
*
- * This module allows virtio devices to be used over a vhost-user socket.
+ * This driver allows virtio devices to be used over a vhost-user socket.
*
* Guest devices can be instantiated by kernel module or command line
* parameters. One device will be created for each parameter. Syntax:
*
- * [virtio_uml.]device=<socket>:<virtio_id>[:<platform_id>]
+ * virtio_uml.device=<socket>:<virtio_id>[:<platform_id>]
* where:
* <socket> := vhost-user socket path to connect
* <virtio_id> := virtio device id (as in virtio_ids.h)