Virtualization - Oct 2022 - [RFC PATCH] virtio: document virtio hardening status and TODO

This patch summarizes the status of hardening and TODO of hardening
virtio core and drivers.

Signed-off-by: Jason Wang <jasowang at redhat.com>
---
 Documentation/security/virtio/core.rst | 49 ++++++++++++++++++++++++++
 MAINTAINERS                            |  1 +
 2 files changed, 50 insertions(+)
 create mode 100644 Documentation/security/virtio/core.rst

diff --git a/Documentation/security/virtio/core.rst
b/Documentation/security/virtio/core.rst
new file mode 100644
index 000000000000..b8baa104d7c8
--- /dev/null
+++ b/Documentation/security/virtio/core.rst
@@ -0,0 +1,49 @@
+===============+Virtio hardening
+===============+
+The virtio core and drivers should not trust the devices. This means
+all kinds of input from the device must be validated before being
+used. This document summarizes the current status and TODO for this
+validation/hardening efforts.
+
+
+Status
+=====+
+The virtio core and drivers has done some basic hardening:
+
+* Config callback hardening: The core makes sure the config interrupt
+  callbacks are enabled after the driver is ready and disable before
+  the driver is removed.
+
+* Descriptor ring hardening: The metadata of a descriptor were copied
+  and stored in a driver private memory that can not be accessed by the
+  device. The eliminates the device triggerable behaviours through the
+  descriptor ring.
+
+* Device configuration space validation: Some of the virtio drivers
+  validates the fields of device configuration space before try to use
+  them.
+
+
+TODO
+===+
+* Input buffer length validation: The virtio core needs to validate
+  the input buffer length validation before passing them to individual
+  virtio drivers.
+
+* Virtqueue callback hardening: The virtio core (or with the help of
+  the drivers) should guarantee that the virtqueue callbacks should not
+  be triggered before the driver is ready or after the driver is
+  removed.
+
+* Transport specific data validation: The virtio transport driver should
+  validate the virtio transport specific data provided by the device
+  before trying to use them in the probing.
+
+* Device specific validation: Driver should validate the device specific
+  metadata before being used by a specific subsystem.
+
+
diff --git a/MAINTAINERS b/MAINTAINERS
index 673b9f9b8d8a..b33cc5c751c1 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -21516,6 +21516,7 @@ S:	Maintained
 F:	Documentation/ABI/testing/sysfs-bus-vdpa
 F:	Documentation/ABI/testing/sysfs-class-vduse
 F:	Documentation/devicetree/bindings/virtio/
+F:	Documentation/security/virtio/core.rst
 F:	drivers/block/virtio_blk.c
 F:	drivers/crypto/virtio/
 F:	drivers/net/virtio_net.c
-- 
2.25.1

Jason Wang <jasowang at redhat.com> writes:
> This patch summarizes the status of hardening and TODO of hardening
> virtio core and drivers.
>
> Signed-off-by: Jason Wang <jasowang at redhat.com>
> ---
>  Documentation/security/virtio/core.rst | 49 ++++++++++++++++++++++++++
>  MAINTAINERS                            |  1 +
>  2 files changed, 50 insertions(+)
>  create mode 100644 Documentation/security/virtio/core.rst
Do you really need to create a new directory for a single file?

Regardless of where it sits, you'll need to add this file to an
index.rst file so that it becomes part of the docs build.

Thanks,

jon

I'm not a native speaker, so the following suggestions can be wrong :-)

On Fri, Oct 14, 2022 at 12:20:37PM +0800, Jason Wang
wrote:
>This patch summarizes the status of hardening and TODO of hardening
>virtio core and drivers.
>
>Signed-off-by: Jason Wang <jasowang at redhat.com>
>---
> Documentation/security/virtio/core.rst | 49 ++++++++++++++++++++++++++
> MAINTAINERS                            |  1 +
> 2 files changed, 50 insertions(+)
> create mode 100644 Documentation/security/virtio/core.rst
>
>diff --git a/Documentation/security/virtio/core.rst
b/Documentation/security/virtio/core.rst
>new file mode 100644
>index 000000000000..b8baa104d7c8
>--- /dev/null
>+++ b/Documentation/security/virtio/core.rst
>@@ -0,0 +1,49 @@
>+===============>+Virtio hardening
>+===============>+
>+The virtio core and drivers should not trust the devices. This means
>+all kinds of input from the device must be validated before being
>+used. This document summarizes the current status and TODO for this
>+validation/hardening efforts.
s/efforts/effort
>+
>+
>+Status
>+=====>+
>+The virtio core and drivers has done some basic hardening:
>+
>+* Config callback hardening: The core makes sure the config interrupt
>+  callbacks are enabled after the driver is ready and disable before
>+  the driver is removed.
>+
>+* Descriptor ring hardening: The metadata of a descriptor were copied
>+  and stored in a driver private memory that can not be accessed by the
>+  device. The eliminates the device triggerable behaviours through the
s/The/This ? (not sure)
)
>+  descriptor ring.
>+
>+* Device configuration space validation: Some of the virtio drivers
>+  validates the fields of device configuration space before try to use
s/validates/validate
>+  them.
>+
>+
>+TODO
>+===>+
>+* Input buffer length validation: The virtio core needs to validate
>+  the input buffer length validation before passing them to individual
Remove "validation"?
>+  virtio drivers.
>+
>+* Virtqueue callback hardening: The virtio core (or with the help of
>+  the drivers) should guarantee that the virtqueue callbacks should not
>+  be triggered before the driver is ready or after the driver is
>+  removed.
>+
>+* Transport specific data validation: The virtio transport driver should
>+  validate the virtio transport specific data provided by the device
>+  before trying to use them in the probing.
s/in the probing/during the probe   ?
>+
>+* Device specific validation: Driver should validate the device specific
>+  metadata before being used by a specific subsystem.
>+
>+
>diff --git a/MAINTAINERS b/MAINTAINERS
>index 673b9f9b8d8a..b33cc5c751c1 100644
>--- a/MAINTAINERS
>+++ b/MAINTAINERS
>@@ -21516,6 +21516,7 @@ S:	Maintained
> F:	Documentation/ABI/testing/sysfs-bus-vdpa
> F:	Documentation/ABI/testing/sysfs-class-vduse
> F:	Documentation/devicetree/bindings/virtio/
>+F:	Documentation/security/virtio/core.rst
> F:	drivers/block/virtio_blk.c
> F:	drivers/crypto/virtio/
> F:	drivers/net/virtio_net.c
>-- 
>2.25.1
>
Thanks,
Stefano