linux.git/drivers/thunderbolt/switch.c, branch v4.13-rc2

thunderbolt: Correct access permissions for active NVM contents

2017-07-17T13:55:08+00:00

Firmware upgrade tools that decide which NVM image should be uploaded to
the Thunderbolt controller need to access active parts of the NVM even
if they are not run as root. The information in active NVM is not
considered security critical so we can use the default permissions set
by the NVMem framework.

Writing the NVM image is still left as root only operation.

While there mark the active NVM as read-only in the filesystem.

Reported-by: Yehezkel Bernat 
Signed-off-by: Mika Westerberg 
Signed-off-by: Andreas Noever 
Signed-off-by: Greg Kroah-Hartman

thunderbolt: Add support for host and device NVM firmware upgrade

2017-06-09T09:42:43+00:00

Starting from Intel Falcon Ridge the NVM firmware can be upgraded by
using DMA configuration based mailbox commands. If we detect that the
host or device (device support starts from Intel Alpine Ridge) has the
DMA configuration based mailbox we expose NVM information to the
userspace as two separate Linux NVMem devices: nvm_active and
nvm_non_active. The former is read-only portion of the active NVM which
firmware upgrade tools can be use to find out suitable NVM image if the
device identification strings are not enough.

The latter is write-only portion where the new NVM image is to be
written by the userspace. It is up to the userspace to find out right
NVM image (the kernel does very minimal validation). The ICM firmware
itself authenticates the new NVM firmware and fails the operation if it
is not what is expected.

We also expose two new sysfs files per each switch: nvm_version and
nvm_authenticate which can be used to read the active NVM version and
start the upgrade process.

We also introduce safe mode which is the mode a switch goes when it does
not have properly authenticated firmware. In this mode the switch only
accepts a couple of commands including flashing a new NVM firmware image
and triggering power cycle.

This code is based on the work done by Amir Levy and Michael Jamet.

Signed-off-by: Michael Jamet 
Signed-off-by: Mika Westerberg 
Reviewed-by: Yehezkel Bernat 
Reviewed-by: Andy Shevchenko 
Signed-off-by: Andreas Noever 
Signed-off-by: Greg Kroah-Hartman

thunderbolt: Add support for Internal Connection Manager (ICM)

2017-06-09T09:42:43+00:00

Starting from Intel Falcon Ridge the internal connection manager running
on the Thunderbolt host controller has been supporting 4 security
levels. One reason for this is to prevent DMA attacks and only allow
connecting devices the user trusts.

The internal connection manager (ICM) is the preferred way of connecting
Thunderbolt devices over software only implementation typically used on
Macs. The driver communicates with ICM using special Thunderbolt ring 0
(control channel) messages. In order to handle these messages we add
support for the ICM messages to the control channel.

The security levels are as follows:

  none - No security, all tunnels are created automatically
  user - User needs to approve the device before tunnels are created
  secure - User need to approve the device before tunnels are created.
	   The device is sent a challenge on future connects to be able
	   to verify it is actually the approved device.
  dponly - Only Display Port and USB tunnels can be created and those
           are created automatically.

The security levels are typically configurable from the system BIOS and
by default it is set to "user" on many systems.

In this patch each Thunderbolt device will have either one or two new
sysfs attributes: authorized and key. The latter appears for devices
that support secure connect.

In order to identify the device the user can read identication
information, including UUID and name of the device from sysfs and based
on that make a decision to authorize the device. The device is
authorized by simply writing 1 to the "authorized" sysfs attribute. This
is following the USB bus device authorization mechanism. The secure
connect requires an additional challenge step (writing 2 to the
"authorized" attribute) in future connects when the key has already been
stored to the NVM of the device.

Non-ICM systems (before Alpine Ridge) continue to use the existing
functionality and the security level is set to none. For systems with
Alpine Ridge, even on Apple hardware, we will use ICM.

This code is based on the work done by Amir Levy and Michael Jamet.

Signed-off-by: Michael Jamet 
Signed-off-by: Mika Westerberg 
Reviewed-by: Yehezkel Bernat 
Reviewed-by: Andy Shevchenko 
Signed-off-by: Andreas Noever 
Signed-off-by: Greg Kroah-Hartman

thunderbolt: Add support for DMA configuration based mailbox

2017-06-09T09:42:43+00:00

The DMA (NHI) port of a switch provides access to the NVM of the host
controller (and devices starting from Intel Alpine Ridge). The NVM
contains also more complete DROM for the root switch including vendor
and device identification strings.

This will look for the DMA port capability for each switch and if found
populates sw->dma_port. We then teach tb_drom_read() to read the DROM
information from NVM if available for the root switch.

The DMA port capability also supports upgrading the NVM for both host
controller and devices which will be added in subsequent patches.

This code is based on the work done by Amir Levy and Michael Jamet.

Signed-off-by: Michael Jamet 
Signed-off-by: Mika Westerberg 
Reviewed-by: Yehezkel Bernat 
Reviewed-by: Andy Shevchenko 
Signed-off-by: Andreas Noever 
Signed-off-by: Greg Kroah-Hartman

thunderbolt: Store Thunderbolt generation in the switch structure

2017-06-09T09:42:43+00:00

In some cases it is useful to know what is the Thunderbolt generation
the switch supports. This introduces a new field to struct switch that
stores the generation of the switch based on the device ID. Unknown
switches (there should be none) are assumed to be first generation to be
on the safe side.

Signed-off-by: Mika Westerberg 
Reviewed-by: Yehezkel Bernat 
Reviewed-by: Michael Jamet 
Reviewed-by: Andy Shevchenko 
Signed-off-by: Andreas Noever 
Signed-off-by: Greg Kroah-Hartman

thunderbolt: Add new Thunderbolt PCI IDs

2017-06-09T09:42:43+00:00

Add Intel Win Ridge (Thunderbolt 2) and Alpine Ridge (Thunderbolt 3)
controller PCI IDs to the list of supported devices.

This code is based on the work done by Amir Levy and Michael Jamet.

Signed-off-by: Michael Jamet 
Signed-off-by: Mika Westerberg 
Reviewed-by: Yehezkel Bernat 
Reviewed-by: Andy Shevchenko 
Signed-off-by: Andreas Noever 
Signed-off-by: Greg Kroah-Hartman

thunderbolt: Read vendor and device name from DROM

2017-06-09T09:42:42+00:00

The device DROM contains name of the vendor and device among other
things. Extract this information and expose it to the userspace via two
new attributes.

Signed-off-by: Mika Westerberg 
Reviewed-by: Yehezkel Bernat 
Reviewed-by: Michael Jamet 
Signed-off-by: Andreas Noever 
Signed-off-by: Greg Kroah-Hartman

thunderbolt: Fail switch adding operation if reading DROM fails

2017-06-09T09:42:42+00:00

All non-root switches are expected to have DROM so if the operation
fails, it might be due the user unlugging the device. There is no point
continuing adding the switch further in that case. Just bail out.

For root switches (hosts) the DROM is either retrieved from a EFI
variable, NVM or hard-coded.

Signed-off-by: Mika Westerberg 
Reviewed-by: Yehezkel Bernat 
Reviewed-by: Michael Jamet 
Reviewed-by: Andy Shevchenko 
Signed-off-by: Andreas Noever 
Signed-off-by: Greg Kroah-Hartman

thunderbolt: Convert switch to a device

2017-06-09T09:42:42+00:00

Thunderbolt domain consists of switches that are connected to each
other, forming a bus. This will convert each switch into a real Linux
device structure and adds them to the domain. The advantage here is
that we get all the goodies from the driver core, like reference
counting and sysfs hierarchy for free.

Also expose device identification information to the userspace via new
sysfs attributes.

In order to support internal connection manager (ICM) we separate switch
configuration into its own function (tb_switch_configure()) which is
only called by the existing native connection manager implementation
used on Macs.

Signed-off-by: Mika Westerberg 
Reviewed-by: Yehezkel Bernat 
Reviewed-by: Michael Jamet 
Reviewed-by: Andy Shevchenko 
Signed-off-by: Andreas Noever 
Signed-off-by: Greg Kroah-Hartman

thunderbolt: Rework capability handling

2017-06-09T09:42:41+00:00

Organization of the capabilities in switches and ports is not so random
after all. Rework the capability handling functionality so that it
follows how capabilities are organized and provide two new functions
(tb_switch_find_vse_cap() and tb_port_find_cap()) which can be used to
extract capabilities for ports and switches. Then convert the current
users over these.

Signed-off-by: Mika Westerberg 
Reviewed-by: Yehezkel Bernat 
Reviewed-by: Michael Jamet 
Reviewed-by: Andy Shevchenko 
Signed-off-by: Andreas Noever 
Signed-off-by: Greg Kroah-Hartman