On Thu, Feb 1, 2024 at 7:04 AM Randy Dunlap rdunlap@infradead.org wrote:

Hi,

On 1/31/24 09:43, Jens Wiklander wrote:

...

A number of storage technologies support a specialised hardware partition designed to be resistant to replay attacks. The underlying HW protocols differ but the operations are common. The RPMB partition cannot be accessed via standard block layer, but by a set of specific RPMB commands: WRITE, READ, GET_WRITE_COUNTER, and PROGRAM_KEY. Such a partition provides authenticated and replay protected access, hence suitable as a secure storage.

The initial aim of this patch is to provide a simple RPMB Driver which can be accessed by the optee driver to facilitate early RPMB access to OP-TEE OS (secure OS) during the boot time.

A TEE device driver can claim the RPMB interface, for example, via class_interface_register() or rpmb_dev_find_device(). The RPMB driver provides a callback to route RPMB frames to the RPMB device accessible via rpmb_route_frames().

The detailed operation of implementing the access is left to the TEE device driver itself.

Signed-off-by: Tomas Winkler tomas.winkler@intel.com Signed-off-by: Alex Bennée alex.bennee@linaro.org Signed-off-by: Shyam Saini shyamsaini@linux.microsoft.com Signed-off-by: Jens Wiklander jens.wiklander@linaro.org

---

MAINTAINERS | 7 ++ drivers/misc/Kconfig | 9 ++ drivers/misc/Makefile | 1 + drivers/misc/rpmb-core.c | 247 +++++++++++++++++++++++++++++++++++++++ include/linux/rpmb.h | 184 +++++++++++++++++++++++++++++ 5 files changed, 448 insertions(+) create mode 100644 drivers/misc/rpmb-core.c create mode 100644 include/linux/rpmb.h

...

diff --git a/drivers/misc/Kconfig b/drivers/misc/Kconfig index 4fb291f0bf7c..891aa5763666 100644 --- a/drivers/misc/Kconfig +++ b/drivers/misc/Kconfig @@ -104,6 +104,15 @@ config PHANTOM If you choose to build module, its name will be phantom. If unsure, say N here.

+config RPMB

• tristate "RPMB partition interface"
  

• help
  

•   Unified RPMB unit interface for RPMB capable devices such as eMMC and
  

•   UFS. Provides interface for in kernel security controllers to access
  

                                  in-kernel

...

•   RPMB unit.
  

•   If unsure, select N.
  

config TIFM_CORE tristate "TI Flash Media interface support" depends on PCI

...

diff --git a/drivers/misc/rpmb-core.c b/drivers/misc/rpmb-core.c new file mode 100644 index 000000000000..a3c289051687 --- /dev/null +++ b/drivers/misc/rpmb-core.c @@ -0,0 +1,247 @@ +// SPDX-License-Identifier: GPL-2.0 +/*

• • Copyright(c) 2015 - 2019 Intel Corporation. All rights reserved.
• • Copyright(c) 2021 - 2024 Linaro Ltd.
• */

+#include <linux/device.h> +#include <linux/init.h> +#include <linux/kernel.h> +#include <linux/list.h> +#include <linux/module.h> +#include <linux/mutex.h> +#include <linux/rpmb.h> +#include <linux/slab.h>

...

+/**

• • rpmb_route_frames() - route rpmb frames to rpmb device
• • @rdev: rpmb device
• • @req: rpmb request frames
• • @req_len: length of rpmb request frames in bytes
• • @rsp: rpmb response frames
• • @rsp_len: length of rpmb response frames in bytes
• • @return < 0 on failure

Above needs a colon ':' after @return, although using

• Return:

is preferable IMO.

Thanks, I'll change to "* Return:" instead, everywhere in this patch.

...

• */

+int rpmb_route_frames(struct rpmb_dev *rdev, u8 *req,

•               unsigned int req_len, u8 *rsp, unsigned int rsp_len)
  

+{

...

+/**

• • rpmb_dev_find_device() - return first matching rpmb device
• • @data: data for the match function
• • @match: the matching function
• • @returns a matching rpmb device or NULL on failure

* @returns:

or * Returns:

...

• */

+struct rpmb_dev *rpmb_dev_find_device(const void *data,

•                               const struct rpmb_dev *start,
  

•                               int (*match)(struct device *dev,
  

•                                            const void *data))
  

+{

• struct device *dev;
  

• const struct device *start_dev = NULL;
  

• if (start)
  

•         start_dev = &start->dev;
  

• dev = class_find_device(&rpmb_class, start_dev, data, match);
  

• return dev ? to_rpmb_dev(dev) : NULL;
  

+}

+/**

• • rpmb_dev_unregister() - unregister RPMB partition from the RPMB subsystem
• • @rdev: the rpmb device to unregister
• • @returns < 0 on failure

Ditto.

...

• */

+int rpmb_dev_unregister(struct rpmb_dev *rdev) +{

• if (!rdev)
  

•         return -EINVAL;
  

• device_del(&rdev->dev);
  

• rpmb_dev_put(rdev);
  

• return 0;
  

+} +EXPORT_SYMBOL_GPL(rpmb_dev_unregister);

+/**

• • rpmb_dev_register - register RPMB partition with the RPMB subsystem
• • @dev: storage device of the rpmb device
• • @target: RPMB target/region within the physical device

There is no @target function parameter.

You're right, I'll remove it.

...

• • @ops: device specific operations
• • While registering the RPMB partition get references to needed resources
• • with the @ops->get_resources() callback and extracts needed devices
• • information while needed resources are available.
• • @returns a pointer to a 'struct rpmb_dev' or an ERR_PTR on failure

Ditto for Return syntax.

...

• */

+struct rpmb_dev *rpmb_dev_register(struct device *dev,

•                            const struct rpmb_ops *ops)
  

+{

• struct rpmb_dev *rdev;
  

• int id;
  

• int ret;
  

• if (!dev || !ops || !ops->get_resources ||
  

•     !ops->put_resources || !ops->route_frames ||
  

•     !ops->set_dev_info)
  

•         return ERR_PTR(-EINVAL);
  

• rdev = kzalloc(sizeof(*rdev), GFP_KERNEL);
  

• if (!rdev)
  

•         return ERR_PTR(-ENOMEM);
  

• mutex_lock(&rpmb_mutex);
  

• id = ida_simple_get(&rpmb_ida, 0, 0, GFP_KERNEL);
  

• mutex_unlock(&rpmb_mutex);
  

• if (id < 0) {
  

•         ret = id;
  

•         goto exit;
  

• }
  

• rdev->ops = ops;
  

• rdev->id = id;
  

• dev_set_name(&rdev->dev, "rpmb%d", id);
  

• rdev->dev.class = &rpmb_class;
  

• rdev->dev.parent = dev;
  

• ret = ops->set_dev_info(dev, rdev);
  

• if (ret)
  

•         goto exit;
  

• ret = device_register(&rdev->dev);
  

• if (ret)
  

•         goto exit;
  

• ops->get_resources(rdev->dev.parent);
  

• dev_dbg(&rdev->dev, "registered device\n");
  

• return rdev;
  

+exit:

• if (id >= 0) {
  

•         mutex_lock(&rpmb_mutex);
  

•         ida_simple_remove(&rpmb_ida, id);
  

•         mutex_unlock(&rpmb_mutex);
  

• }
  

• kfree(rdev);
  

• return ERR_PTR(ret);
  

+} +EXPORT_SYMBOL_GPL(rpmb_dev_register);

...

diff --git a/include/linux/rpmb.h b/include/linux/rpmb.h new file mode 100644 index 000000000000..45073513264a --- /dev/null +++ b/include/linux/rpmb.h @@ -0,0 +1,184 @@ +/* SPDX-License-Identifier: BSD-3-Clause OR GPL-2.0 */ +/*

• • Copyright (C) 2015-2019 Intel Corp. All rights reserved
• • Copyright (C) 2021-2022 Linaro Ltd
• */

+#ifndef __RPMB_H__ +#define __RPMB_H__

+#include <linux/types.h> +#include <linux/device.h>

+/**

• • struct rpmb_frame - rpmb frame as defined by specs
• • @stuff : stuff bytes
• • @key_mac : The authentication key or the message authentication

• •             code (MAC) depending on the request/response type.
    

• •             The MAC will be delivered in the last (or the only)
    

• •             block of data.
    

• • @data : Data to be written or read by signed access.
• • @nonce : Random number generated by the host for the requests

• •             and copied to the response by the RPMB engine.
    

• • @write_counter: Counter value for the total amount of the successful

• •             authenticated data write requests made by the host.
    

• • @addr : Address of the data to be programmed to or read

• •             from the RPMB. Address is the serial number of
    

• •             the accessed block (half sector 256B).
    

• • @block_count : Number of blocks (half sectors, 256B) requested to be

• •             read/programmed.
    

• • @result : Includes information about the status of the write counter

• •             (valid, expired) and result of the access made to the RPMB.
    

• • @req_resp : Defines the type of request and response to/from the memory.
• */

+struct rpmb_frame {

• u8     stuff[196];
  

• u8     key_mac[32];
  

• u8     data[256];
  

• u8     nonce[16];
  

• __be32 write_counter;
  

• __be16 addr;
  

• __be16 block_count;
  

• __be16 result;
  

• __be16 req_resp;
  

+} __packed;

+#define RPMB_PROGRAM_KEY 0x1 /* Program RPMB Authentication Key */ +#define RPMB_GET_WRITE_COUNTER 0x2 /* Read RPMB write counter */ +#define RPMB_WRITE_DATA 0x3 /* Write data to RPMB partition */ +#define RPMB_READ_DATA 0x4 /* Read data from RPMB partition */ +#define RPMB_RESULT_READ 0x5 /* Read result request (Internal) */

+#define RPMB_REQ2RESP(_OP) ((_OP) << 8) +#define RPMB_RESP2REQ(_OP) ((_OP) >> 8)

+/**

• • enum rpmb_op_result - rpmb operation results
• • @RPMB_ERR_OK : operation successful
• • @RPMB_ERR_GENERAL : general failure
• • @RPMB_ERR_AUTH : mac doesn't match or ac calculation failure
• • @RPMB_ERR_COUNTER : counter doesn't match or counter increment failure
• • @RPMB_ERR_ADDRESS : address out of range or wrong address alignment
• • @RPMB_ERR_WRITE : data, counter, or result write failure
• • @RPMB_ERR_READ : data, counter, or result read failure
• • @RPMB_ERR_NO_KEY : authentication key not yet programmed
• • @RPMB_ERR_COUNTER_EXPIRED: counter expired
• */

+enum rpmb_op_result {

• RPMB_ERR_OK      = 0x0000,
  

• RPMB_ERR_GENERAL = 0x0001,
  

• RPMB_ERR_AUTH    = 0x0002,
  

• RPMB_ERR_COUNTER = 0x0003,
  

• RPMB_ERR_ADDRESS = 0x0004,
  

• RPMB_ERR_WRITE   = 0x0005,
  

• RPMB_ERR_READ    = 0x0006,
  

• RPMB_ERR_NO_KEY  = 0x0007,
  

• RPMB_ERR_COUNTER_EXPIRED = 0x0080
  

+};

+/**

• • enum rpmb_type - type of underlaying storage technology

                           underlying

Thanks

...

• • @RPMB_TYPE_EMMC : emmc (JESD84-B50.1)
• • @RPMB_TYPE_UFS : UFS (JESD220)
• • @RPMB_TYPE_NVME : NVM Express
• */

+enum rpmb_type {

• RPMB_TYPE_EMMC,
  

• RPMB_TYPE_UFS,
  

• RPMB_TYPE_NVME,
  

+};

+/**

• • struct rpmb_dev - device which can support RPMB partition
• • @dev : device
• • @id : device id;
• • @ops : operation exported by rpmb
• • @dev_id : unique device identifier read from the hardware
• • @dev_id_len : length of unique device identifier
• • @reliable_wr_count: number of sectors that can be written in one access
• • @capacity : capacity of the device in units of 128K
• */

+struct rpmb_dev {

• struct device dev;
  

• int id;
  

• const struct rpmb_ops *ops;
  

• u8 *dev_id;
  

• size_t dev_id_len;
  

• u16 reliable_wr_count;
  

• u16 capacity;
  

+};

+#define to_rpmb_dev(x) container_of((x), struct rpmb_dev, dev)

+/**

• • struct rpmb_ops - RPMB ops to be implemented by underlying block device
• • @type : block device type
• • @get_resources : gets references to needed resources in rpmb_dev_register()
• • @put_resources : puts references from resources in rpmb_dev_release()
• • @route_frames : routes frames to and from the RPMB device
• • @get_dev_info : extracts device info from the RPMB device

   set_dev_info ???

Yes.

Thanks, Jens

...

• */

+struct rpmb_ops {

• enum rpmb_type type;
  

• void (*get_resources)(struct device *dev);
  

• void (*put_resources)(struct device *dev);
  

• int (*set_dev_info)(struct device *dev, struct rpmb_dev *rdev);
  

• int (*route_frames)(struct device *dev, bool write,
  

•                     u8 *req, unsigned int req_len,
  

•                     u8 *resp, unsigned int resp_len);
  

+};

thanks.

#Randy

Hi Ulf,

On Tue, 6 Feb 2024 at 14:34, Ulf Hansson ulf.hansson@linaro.org wrote:

On Wed, 31 Jan 2024 at 18:44, Jens Wiklander jens.wiklander@linaro.org wrote:

...

A number of storage technologies support a specialised hardware partition designed to be resistant to replay attacks. The underlying HW protocols differ but the operations are common. The RPMB partition cannot be accessed via standard block layer, but by a set of specific RPMB commands: WRITE, READ, GET_WRITE_COUNTER, and PROGRAM_KEY. Such a partition provides authenticated and replay protected access, hence suitable as a secure storage.

The initial aim of this patch is to provide a simple RPMB Driver which can be accessed by the optee driver to facilitate early RPMB access to OP-TEE OS (secure OS) during the boot time.

How early do we expect OP-TEE to need RPMB access?

It depends on the requested services. I am currently aware of 2 services that depend on the RPMB - FirmwareTPM - UEFI variables stored there via optee.

For the FirmwareTPM it depends on when you want to use it. This typically happens when the initramfs is loaded or systemd requests access to the TPM. I guess this is late enough to not cause problems?

For the latter, we won't need the supplicant until a write is requested. This will only happen once the userspace is up and running. The UEFI driver that sits behind OP-TEE has an in-memory cache of the variables, so all the reads (the kernel invokes get_next_variable during boot) are working without it.

Thanks /Ilias

The way things work for mmc today, is that the eMMC card gets discovered/probed via a workqueue. The work is punted by the mmc host driver (typically a module-platform-driver), when it has probed successfully.

The point is, it looks like we need some kind of probe deferral mechanism too. Whether we want the OP-TEE driver to manage this itself or whether we should let rpmb_dev_find_device() deal with it, I don't know.

...

A TEE device driver can claim the RPMB interface, for example, via class_interface_register() or rpmb_dev_find_device(). The RPMB driver provides a callback to route RPMB frames to the RPMB device accessible via rpmb_route_frames().

By looking at the design of the interface, I do like it. It's simple and straightforward.

However, I wonder if you considered avoiding using a class-device altogether? Even if it helps with lifecycle problems and the ops-lookup, we really don't need another struct device with a sysfs node, etc.

To deal with the lifecycle issue, we could probably just add reference counting for the corresponding struct device that we already have at hand, which represents the eMMC/UFS/NVME card. That together with a simple list that contains the registered rpmb ops. But I may be overlooking something, so perhaps it's more complicated than that?

...

The detailed operation of implementing the access is left to the TEE device driver itself.

Signed-off-by: Tomas Winkler tomas.winkler@intel.com Signed-off-by: Alex Bennée alex.bennee@linaro.org Signed-off-by: Shyam Saini shyamsaini@linux.microsoft.com Signed-off-by: Jens Wiklander jens.wiklander@linaro.org

---

MAINTAINERS | 7 ++ drivers/misc/Kconfig | 9 ++ drivers/misc/Makefile | 1 + drivers/misc/rpmb-core.c | 247 +++++++++++++++++++++++++++++++++++++++ include/linux/rpmb.h | 184 +++++++++++++++++++++++++++++ 5 files changed, 448 insertions(+) create mode 100644 drivers/misc/rpmb-core.c create mode 100644 include/linux/rpmb.h

diff --git a/MAINTAINERS b/MAINTAINERS index 8999497011a2..e83152c42499 100644 --- a/MAINTAINERS +++ b/MAINTAINERS @@ -19012,6 +19012,13 @@ T: git git://linuxtv.org/media_tree.git F: Documentation/devicetree/bindings/media/allwinner,sun8i-a83t-de2-rotate.yaml F: drivers/media/platform/sunxi/sun8i-rotate/

+RPMB SUBSYSTEM +M: Jens Wiklander jens.wiklander@linaro.org +L: linux-kernel@vger.kernel.org +S: Supported +F: drivers/misc/rpmb-core.c +F: include/linux/rpmb.h

RPMSG TTY DRIVER M: Arnaud Pouliquen arnaud.pouliquen@foss.st.com L: linux-remoteproc@vger.kernel.org diff --git a/drivers/misc/Kconfig b/drivers/misc/Kconfig index 4fb291f0bf7c..891aa5763666 100644 --- a/drivers/misc/Kconfig +++ b/drivers/misc/Kconfig @@ -104,6 +104,15 @@ config PHANTOM If you choose to build module, its name will be phantom. If unsure, say N here.

+config RPMB

•   tristate "RPMB partition interface"
  

Should we add a "depends on MMC"? (We can add the other NVME and UFS later on too).

...

•   help
  

•     Unified RPMB unit interface for RPMB capable devices such as eMMC and
  

•     UFS. Provides interface for in kernel security controllers to access
  

•     RPMB unit.
  

•     If unsure, select N.
  

config TIFM_CORE tristate "TI Flash Media interface support" depends on PCI diff --git a/drivers/misc/Makefile b/drivers/misc/Makefile index ea6ea5bbbc9c..8af058ad1df4 100644 --- a/drivers/misc/Makefile +++ b/drivers/misc/Makefile @@ -15,6 +15,7 @@ obj-$(CONFIG_LKDTM) += lkdtm/ obj-$(CONFIG_TIFM_CORE) += tifm_core.o obj-$(CONFIG_TIFM_7XX1) += tifm_7xx1.o obj-$(CONFIG_PHANTOM) += phantom.o +obj-$(CONFIG_RPMB) += rpmb-core.o obj-$(CONFIG_QCOM_COINCELL) += qcom-coincell.o obj-$(CONFIG_QCOM_FASTRPC) += fastrpc.o obj-$(CONFIG_SENSORS_BH1770) += bh1770glc.o diff --git a/drivers/misc/rpmb-core.c b/drivers/misc/rpmb-core.c new file mode 100644 index 000000000000..a3c289051687 --- /dev/null +++ b/drivers/misc/rpmb-core.c @@ -0,0 +1,247 @@ +// SPDX-License-Identifier: GPL-2.0 +/*

• • Copyright(c) 2015 - 2019 Intel Corporation. All rights reserved.
• • Copyright(c) 2021 - 2024 Linaro Ltd.
• */

+#include <linux/device.h> +#include <linux/init.h> +#include <linux/kernel.h> +#include <linux/list.h> +#include <linux/module.h> +#include <linux/mutex.h> +#include <linux/rpmb.h> +#include <linux/slab.h>

+static DEFINE_IDA(rpmb_ida); +static DEFINE_MUTEX(rpmb_mutex);

+/**

• • rpmb_dev_get() - increase rpmb device ref counter
• • @rdev: rpmb device
• */

+struct rpmb_dev *rpmb_dev_get(struct rpmb_dev *rdev) +{

•   if (rdev)
  

•           get_device(&rdev->dev);
  

•   return rdev;
  

+} +EXPORT_SYMBOL_GPL(rpmb_dev_get);

+/**

• • rpmb_dev_put() - decrease rpmb device ref counter
• • @rdev: rpmb device
• */

+void rpmb_dev_put(struct rpmb_dev *rdev) +{

•   if (rdev)
  

•           put_device(&rdev->dev);
  

+} +EXPORT_SYMBOL_GPL(rpmb_dev_put);

+/**

• • rpmb_route_frames() - route rpmb frames to rpmb device
• • @rdev: rpmb device
• • @req: rpmb request frames
• • @req_len: length of rpmb request frames in bytes
• • @rsp: rpmb response frames
• • @rsp_len: length of rpmb response frames in bytes
• • @return < 0 on failure
• */

+int rpmb_route_frames(struct rpmb_dev *rdev, u8 *req,

•                 unsigned int req_len, u8 *rsp, unsigned int rsp_len)
  

+{

•   struct rpmb_frame *frm = (struct rpmb_frame *)req;
  

Is there a reason why we are passing an u8 *req, in favor of a "rpmb_frame *frame" directly as the in-parameter?

...

•   u16 req_type;
  

•   bool write;
  

•   if (!req || req_len < sizeof(*frm) || !rsp || !rsp_len)
  

•           return -EINVAL;
  

•   req_type = be16_to_cpu(frm->req_resp);
  

•   switch (req_type) {
  

•   case RPMB_PROGRAM_KEY:
  

•           if (req_len != sizeof(struct rpmb_frame) ||
  

•               rsp_len != sizeof(struct rpmb_frame))
  

•                   return -EINVAL;
  

•           write = true;
  

•           break;
  

•   case RPMB_GET_WRITE_COUNTER:
  

•           if (req_len != sizeof(struct rpmb_frame) ||
  

•               rsp_len != sizeof(struct rpmb_frame))
  

•                   return -EINVAL;
  

•           write = false;
  

•           break;
  

•   case RPMB_WRITE_DATA:
  

•           if (req_len % sizeof(struct rpmb_frame) ||
  

•               rsp_len != sizeof(struct rpmb_frame))
  

•                   return -EINVAL;
  

•           write = true;
  

•           break;
  

•   case RPMB_READ_DATA:
  

•           if (req_len != sizeof(struct rpmb_frame) ||
  

•               rsp_len % sizeof(struct rpmb_frame))
  

•                   return -EINVAL;
  

•           write = false;
  

•           break;
  

•   default:
  

•           return -EINVAL;
  

•   }
  

•   return rdev->ops->route_frames(rdev->dev.parent, write,
  

•                                  req, req_len, rsp, rsp_len);
  

+} +EXPORT_SYMBOL_GPL(rpmb_route_frames);

[...]

...

+/**

• • enum rpmb_type - type of underlaying storage technology
• • @RPMB_TYPE_EMMC : emmc (JESD84-B50.1)
• • @RPMB_TYPE_UFS : UFS (JESD220)
• • @RPMB_TYPE_NVME : NVM Express
• */

+enum rpmb_type {

•   RPMB_TYPE_EMMC,
  

•   RPMB_TYPE_UFS,
  

•   RPMB_TYPE_NVME,
  

+};

In what way do we expect these to be useful?

Perhaps we should add some information about this, because currently in the series they seem not to be used. Maybe the OP-TEE driver needs it when extending support to NVME and UFS?

[...]

Kind regards Uffe

On Tue, Feb 6, 2024 at 1:34 PM Ulf Hansson ulf.hansson@linaro.org wrote:

On Wed, 31 Jan 2024 at 18:44, Jens Wiklander jens.wiklander@linaro.org wrote:

...

A number of storage technologies support a specialised hardware partition designed to be resistant to replay attacks. The underlying HW protocols differ but the operations are common. The RPMB partition cannot be accessed via standard block layer, but by a set of specific RPMB commands: WRITE, READ, GET_WRITE_COUNTER, and PROGRAM_KEY. Such a partition provides authenticated and replay protected access, hence suitable as a secure storage.

The initial aim of this patch is to provide a simple RPMB Driver which can be accessed by the optee driver to facilitate early RPMB access to OP-TEE OS (secure OS) during the boot time.

How early do we expect OP-TEE to need RPMB access?

The way things work for mmc today, is that the eMMC card gets discovered/probed via a workqueue. The work is punted by the mmc host driver (typically a module-platform-driver), when it has probed successfully.

The point is, it looks like we need some kind of probe deferral mechanism too. Whether we want the OP-TEE driver to manage this itself or whether we should let rpmb_dev_find_device() deal with it, I don't know.

As I wrote in another reply. I'd like to probe the OP-TEE driver without touching RPMB first, and then as the devices start to appear we discover the one to use. In this patchset I'm relying on the OP-TEE client to wait until the RPMB device is available. That's probably good enough for user space client, but I guess not for kernel clients (drivers).

...

A TEE device driver can claim the RPMB interface, for example, via class_interface_register() or rpmb_dev_find_device(). The RPMB driver provides a callback to route RPMB frames to the RPMB device accessible via rpmb_route_frames().

By looking at the design of the interface, I do like it. It's simple and straightforward.

However, I wonder if you considered avoiding using a class-device altogether? Even if it helps with lifecycle problems and the ops-lookup, we really don't need another struct device with a sysfs node, etc.

Yes, the class-device might be more of a leftover from earlier versions with a user space interface too. Let's try to do this without a class-device. I was considering using class_interface_register() for the optee driver to get notified of an eventual RPMB device, but if we don't have an RPMB class device we'll need some other mechanism for that. Perhaps a rpmb_interface_register() with similar callbacks as class_interface_register().

To deal with the lifecycle issue, we could probably just add reference counting for the corresponding struct device that we already have at hand, which represents the eMMC/UFS/NVME card. That together with a simple list that contains the registered rpmb ops. But I may be overlooking something, so perhaps it's more complicated than that?

I could try to call mmc_blk_get() in mmc_blk_alloc_rpmb_part() when storing the md pointer in the newly created struct mmc_rpmb_data. If that works as I hope, then I can get rid of the two get_resources() and put_resources() callbacks. We should probably update mmc_rpmb_chrdev_open() and mmc_rpmb_chrdev_release() to match this.

...

The detailed operation of implementing the access is left to the TEE device driver itself.

Signed-off-by: Tomas Winkler tomas.winkler@intel.com Signed-off-by: Alex Bennée alex.bennee@linaro.org Signed-off-by: Shyam Saini shyamsaini@linux.microsoft.com Signed-off-by: Jens Wiklander jens.wiklander@linaro.org

---

MAINTAINERS | 7 ++ drivers/misc/Kconfig | 9 ++ drivers/misc/Makefile | 1 + drivers/misc/rpmb-core.c | 247 +++++++++++++++++++++++++++++++++++++++ include/linux/rpmb.h | 184 +++++++++++++++++++++++++++++ 5 files changed, 448 insertions(+) create mode 100644 drivers/misc/rpmb-core.c create mode 100644 include/linux/rpmb.h

diff --git a/MAINTAINERS b/MAINTAINERS index 8999497011a2..e83152c42499 100644 --- a/MAINTAINERS +++ b/MAINTAINERS @@ -19012,6 +19012,13 @@ T: git git://linuxtv.org/media_tree.git F: Documentation/devicetree/bindings/media/allwinner,sun8i-a83t-de2-rotate.yaml F: drivers/media/platform/sunxi/sun8i-rotate/

+RPMB SUBSYSTEM +M: Jens Wiklander jens.wiklander@linaro.org +L: linux-kernel@vger.kernel.org +S: Supported +F: drivers/misc/rpmb-core.c +F: include/linux/rpmb.h

RPMSG TTY DRIVER M: Arnaud Pouliquen arnaud.pouliquen@foss.st.com L: linux-remoteproc@vger.kernel.org diff --git a/drivers/misc/Kconfig b/drivers/misc/Kconfig index 4fb291f0bf7c..891aa5763666 100644 --- a/drivers/misc/Kconfig +++ b/drivers/misc/Kconfig @@ -104,6 +104,15 @@ config PHANTOM If you choose to build module, its name will be phantom. If unsure, say N here.

+config RPMB

•   tristate "RPMB partition interface"
  

Should we add a "depends on MMC"? (We can add the other NVME and UFS later on too).

That makes sense, I'll add that.

...

•   help
  

•     Unified RPMB unit interface for RPMB capable devices such as eMMC and
  

•     UFS. Provides interface for in kernel security controllers to access
  

•     RPMB unit.
  

•     If unsure, select N.
  

config TIFM_CORE tristate "TI Flash Media interface support" depends on PCI diff --git a/drivers/misc/Makefile b/drivers/misc/Makefile index ea6ea5bbbc9c..8af058ad1df4 100644 --- a/drivers/misc/Makefile +++ b/drivers/misc/Makefile @@ -15,6 +15,7 @@ obj-$(CONFIG_LKDTM) += lkdtm/ obj-$(CONFIG_TIFM_CORE) += tifm_core.o obj-$(CONFIG_TIFM_7XX1) += tifm_7xx1.o obj-$(CONFIG_PHANTOM) += phantom.o +obj-$(CONFIG_RPMB) += rpmb-core.o obj-$(CONFIG_QCOM_COINCELL) += qcom-coincell.o obj-$(CONFIG_QCOM_FASTRPC) += fastrpc.o obj-$(CONFIG_SENSORS_BH1770) += bh1770glc.o diff --git a/drivers/misc/rpmb-core.c b/drivers/misc/rpmb-core.c new file mode 100644 index 000000000000..a3c289051687 --- /dev/null +++ b/drivers/misc/rpmb-core.c @@ -0,0 +1,247 @@ +// SPDX-License-Identifier: GPL-2.0 +/*

• • Copyright(c) 2015 - 2019 Intel Corporation. All rights reserved.
• • Copyright(c) 2021 - 2024 Linaro Ltd.
• */

+#include <linux/device.h> +#include <linux/init.h> +#include <linux/kernel.h> +#include <linux/list.h> +#include <linux/module.h> +#include <linux/mutex.h> +#include <linux/rpmb.h> +#include <linux/slab.h>

+static DEFINE_IDA(rpmb_ida); +static DEFINE_MUTEX(rpmb_mutex);

+/**

• • rpmb_dev_get() - increase rpmb device ref counter
• • @rdev: rpmb device
• */

+struct rpmb_dev *rpmb_dev_get(struct rpmb_dev *rdev) +{

•   if (rdev)
  

•           get_device(&rdev->dev);
  

•   return rdev;
  

+} +EXPORT_SYMBOL_GPL(rpmb_dev_get);

+/**

• • rpmb_dev_put() - decrease rpmb device ref counter
• • @rdev: rpmb device
• */

+void rpmb_dev_put(struct rpmb_dev *rdev) +{

•   if (rdev)
  

•           put_device(&rdev->dev);
  

+} +EXPORT_SYMBOL_GPL(rpmb_dev_put);

+/**

• • rpmb_route_frames() - route rpmb frames to rpmb device
• • @rdev: rpmb device
• • @req: rpmb request frames
• • @req_len: length of rpmb request frames in bytes
• • @rsp: rpmb response frames
• • @rsp_len: length of rpmb response frames in bytes
• • @return < 0 on failure
• */

+int rpmb_route_frames(struct rpmb_dev *rdev, u8 *req,

•                 unsigned int req_len, u8 *rsp, unsigned int rsp_len)
  

+{

•   struct rpmb_frame *frm = (struct rpmb_frame *)req;
  

Is there a reason why we are passing an u8 *req, in favor of a "rpmb_frame *frame" directly as the in-parameter?

In the OP-TEE driver, we get an arbitrarily sized block of data from the secure world, but we don't interpret it. I expect that it would be the same for any other driver. You get data from somewhere and need to pass it on. With this interface, we can provide the needed sanity checks here instead of forcing each caller to do it instead.

...

•   u16 req_type;
  

•   bool write;
  

•   if (!req || req_len < sizeof(*frm) || !rsp || !rsp_len)
  

•           return -EINVAL;
  

•   req_type = be16_to_cpu(frm->req_resp);
  

•   switch (req_type) {
  

•   case RPMB_PROGRAM_KEY:
  

•           if (req_len != sizeof(struct rpmb_frame) ||
  

•               rsp_len != sizeof(struct rpmb_frame))
  

•                   return -EINVAL;
  

•           write = true;
  

•           break;
  

•   case RPMB_GET_WRITE_COUNTER:
  

•           if (req_len != sizeof(struct rpmb_frame) ||
  

•               rsp_len != sizeof(struct rpmb_frame))
  

•                   return -EINVAL;
  

•           write = false;
  

•           break;
  

•   case RPMB_WRITE_DATA:
  

•           if (req_len % sizeof(struct rpmb_frame) ||
  

•               rsp_len != sizeof(struct rpmb_frame))
  

•                   return -EINVAL;
  

•           write = true;
  

•           break;
  

•   case RPMB_READ_DATA:
  

•           if (req_len != sizeof(struct rpmb_frame) ||
  

•               rsp_len % sizeof(struct rpmb_frame))
  

•                   return -EINVAL;
  

•           write = false;
  

•           break;
  

•   default:
  

•           return -EINVAL;
  

•   }
  

•   return rdev->ops->route_frames(rdev->dev.parent, write,
  

•                                  req, req_len, rsp, rsp_len);
  

+} +EXPORT_SYMBOL_GPL(rpmb_route_frames);

[...]

...

+/**

• • enum rpmb_type - type of underlaying storage technology
• • @RPMB_TYPE_EMMC : emmc (JESD84-B50.1)
• • @RPMB_TYPE_UFS : UFS (JESD220)
• • @RPMB_TYPE_NVME : NVM Express
• */

+enum rpmb_type {

•   RPMB_TYPE_EMMC,
  

•   RPMB_TYPE_UFS,
  

•   RPMB_TYPE_NVME,
  

+};

In what way do we expect these to be useful?

Perhaps we should add some information about this, because currently in the series they seem not to be used. Maybe the OP-TEE driver needs it when extending support to NVME and UFS?

Yes, we need to pass this information to the secure side. I'll update the OP-TEE driver to extract and use the type field from struct rpmb_ops.

Thanks, Jens

[...]

Kind regards Uffe

On Thu, Feb 1, 2024 at 10:18 AM Jorge Ramirez-Ortiz, Foundries jorge@foundries.io wrote:

On 31/01/24 18:43:46, Jens Wiklander wrote:

...

Register eMMC RPMB partition with the RPMB subsystem and provide an implementation for the RPMB access operations abstracting the actual multi step process.

Add callbacks for getting and putting the needed resources, that is, the RPMB data and the RPMB disk.

Add a callback to extract the needed device information at registration to avoid accessing the struct mmc_card at a later stage as we're not holding a reference counter for this struct.

Signed-off-by: Tomas Winkler tomas.winkler@intel.com Signed-off-by: Alexander Usyskin alexander.usyskin@intel.com Signed-off-by: Jens Wiklander jens.wiklander@linaro.org

---

drivers/mmc/core/block.c | 177 +++++++++++++++++++++++++++++++++++++++ 1 file changed, 177 insertions(+)

diff --git a/drivers/mmc/core/block.c b/drivers/mmc/core/block.c index 32d49100dff5..5286e0b3a5a2 100644 --- a/drivers/mmc/core/block.c +++ b/drivers/mmc/core/block.c @@ -33,6 +33,7 @@ #include <linux/cdev.h> #include <linux/mutex.h> #include <linux/scatterlist.h> +#include <linux/string.h> #include <linux/string_helpers.h> #include <linux/delay.h> #include <linux/capability.h> @@ -40,6 +41,7 @@ #include <linux/pm_runtime.h> #include <linux/idr.h> #include <linux/debugfs.h> +#include <linux/rpmb.h>

#include <linux/mmc/ioctl.h> #include <linux/mmc/card.h> @@ -163,6 +165,7 @@ struct mmc_rpmb_data { int id; unsigned int part_index; struct mmc_blk_data *md;

• struct rpmb_dev *rdev;
  struct list_head node;
  

};

@@ -2707,6 +2710,169 @@ static void mmc_blk_rpmb_device_release(struct device *dev) kfree(rpmb); }

+static void rpmb_op_mmc_get_resources(struct device *dev) +{

• struct mmc_rpmb_data *rpmb = dev_get_drvdata(dev);
  

• /*
  

•  * When the MMC card is removed rpmb_dev_unregister() is called
  

•  * from mmc_blk_remove_rpmb_part(). That removes references to the
  

•  * devices in struct mmc_rpmb_data and rpmb->md. Since struct
  

•  * rpmb_dev can still reach those structs we must hold a reference
  

•  * until struct rpmb_dev also is released.
  

•  *
  

•  * This is analogous to what's done in mmc_rpmb_chrdev_open() and
  

•  * mmc_rpmb_chrdev_release() below.
  

•  */
  

• get_device(dev);
  

• mmc_blk_get(rpmb->md->disk);
  

+}

+static void rpmb_op_mmc_put_resources(struct device *dev) +{

• struct mmc_rpmb_data *rpmb = dev_get_drvdata(dev);
  

• mmc_blk_put(rpmb->md);
  

• put_device(dev);
  

+}

+static struct mmc_blk_ioc_data **alloc_idata(struct mmc_rpmb_data *rpmb,

•                                      unsigned int cmd_count)
  

+{

• struct mmc_blk_ioc_data **idata;
  

• unsigned int n;
  

• idata = kcalloc(cmd_count, sizeof(*idata), GFP_KERNEL);
  

• if (!idata)
  

•         return NULL;
  

• for (n = 0; n < cmd_count; n++) {
  

•         idata[n] = kcalloc(1, sizeof(**idata), GFP_KERNEL);
  

•         if (!idata[n]) {
  

•                 kfree(idata);
  

don't you need to unwind these allocations on error?

Yes, you're right.

Thanks, Jens

...

•                 return NULL;
  

•         }
  

•         idata[n]->rpmb = rpmb;
  

• }
  

• return idata;
  

+}

+static void set_idata(struct mmc_blk_ioc_data *idata, u32 opcode,

•               int write_flag, u8 *buf, unsigned int buf_bytes)
  

+{

• idata->ic.opcode = opcode;
  

• idata->ic.flags = MMC_RSP_R1 | MMC_CMD_ADTC;
  

• idata->ic.write_flag = write_flag;
  

• idata->ic.blksz = sizeof(struct rpmb_frame);
  

• idata->ic.blocks = buf_bytes /  idata->ic.blksz;
  

• idata->buf = buf;
  

• idata->buf_bytes = buf_bytes;
  

+}

+static void free_idata(struct mmc_blk_ioc_data **idata, unsigned int cmd_count) +{

• unsigned int n;
  

• for (n = 0; n < cmd_count; n++)
  

•         kfree(idata[n]);
  

• kfree(idata);
  

+}

+static int rpmb_op_mmc_route_frames(struct device *dev, bool write, u8 *req,

•                             unsigned int req_len, u8 *resp,
  

•                             unsigned int resp_len)
  

+{

• struct mmc_rpmb_data *rpmb = dev_get_drvdata(dev);
  

• struct mmc_blk_data *md = rpmb->md;
  

• struct mmc_blk_ioc_data **idata;
  

• unsigned int cmd_count;
  

• struct request *rq;
  

• int ret;
  

• if (write)
  

•         cmd_count = 3;
  

• else
  

•         cmd_count = 2;
  

• if (IS_ERR(md->queue.card))
  

•         return PTR_ERR(md->queue.card);
  

• idata = alloc_idata(rpmb, cmd_count);
  

• if (!idata)
  

•         return -ENOMEM;
  

• if (write) {
  

•         struct rpmb_frame *frm = (struct rpmb_frame *)resp;
  

•         /* Send write request frame(s) */
  

•         set_idata(idata[0], MMC_WRITE_MULTIPLE_BLOCK,
  

•                   1 | MMC_CMD23_ARG_REL_WR, req, req_len);
  

•         /* Send result request frame */
  

•         memset(frm, 0, sizeof(*frm));
  

•         frm->req_resp = cpu_to_be16(RPMB_RESULT_READ);
  

•         set_idata(idata[1], MMC_WRITE_MULTIPLE_BLOCK, 1, resp,
  

•                   resp_len);
  

•         /* Read response frame */
  

•         set_idata(idata[2], MMC_READ_MULTIPLE_BLOCK, 0, resp, resp_len);
  

• } else {
  

•         /* Send write request frame(s) */
  

•         set_idata(idata[0], MMC_WRITE_MULTIPLE_BLOCK, 1, req, req_len);
  

•         /* Read response frame */
  

•         set_idata(idata[1], MMC_READ_MULTIPLE_BLOCK, 0, resp, resp_len);
  

• }
  

• rq = blk_mq_alloc_request(md->queue.queue, REQ_OP_DRV_OUT, 0);
  

• if (IS_ERR(rq)) {
  

•         ret = PTR_ERR(rq);
  

•         goto out;
  

• }
  

• req_to_mmc_queue_req(rq)->drv_op = MMC_DRV_OP_IOCTL_RPMB;
  

• req_to_mmc_queue_req(rq)->drv_op_result = -EIO;
  

• req_to_mmc_queue_req(rq)->drv_op_data = idata;
  

• req_to_mmc_queue_req(rq)->ioc_count = cmd_count;
  

• blk_execute_rq(rq, false);
  

• ret = req_to_mmc_queue_req(rq)->drv_op_result;
  

• blk_mq_free_request(rq);
  

+out:

• free_idata(idata, cmd_count);
  

• return ret;
  

+}

+static int rpmb_op_mmc_set_dev_info(struct device *dev, struct rpmb_dev *rdev) +{

• struct mmc_rpmb_data *rpmb = dev_get_drvdata(dev);
  

• struct mmc_card *card = rpmb->md->queue.card;
  

• unsigned int n;
  

• u32 cid[4];
  

• for (n = 0; n < 4; n++)
  

•         cid[n] = be32_to_cpu(card->raw_cid[n]);
  

• rdev->dev_id = kmemdup(cid, sizeof(cid), GFP_KERNEL);
  

• if (!rdev->dev_id)
  

•         return -ENOMEM;
  

• rdev->dev_id_len = sizeof(cid);
  

• rdev->reliable_wr_count = card->ext_csd.raw_rpmb_size_mult;
  

• rdev->capacity = card->ext_csd.rel_sectors;
  

• return 0;
  

+}

+static struct rpmb_ops rpmb_mmc_ops = {

• .type = RPMB_TYPE_EMMC,
  

• .get_resources = rpmb_op_mmc_get_resources,
  

• .put_resources = rpmb_op_mmc_put_resources,
  

• .route_frames = rpmb_op_mmc_route_frames,
  

• .set_dev_info = rpmb_op_mmc_set_dev_info,
  

+};

static int mmc_blk_alloc_rpmb_part(struct mmc_card *card, struct mmc_blk_data *md, unsigned int part_index, @@ -2751,6 +2917,14 @@ static int mmc_blk_alloc_rpmb_part(struct mmc_card *card, goto out_put_device; }

• rpmb->rdev = rpmb_dev_register(&rpmb->dev, &rpmb_mmc_ops);
  

• if (IS_ERR(rpmb->rdev)) {
  

•         pr_err("%s: could not register RPMB device\n", rpmb_name);
  

•         ret = PTR_ERR(rpmb->rdev);
  

•         rpmb->rdev = NULL;
  

•         goto out_cdev_device_del;
  

• }
  

• list_add(&rpmb->node, &md->rpmbs);
  
  string_get_size((u64)size, 512, STRING_UNITS_2,
  

@@ -2762,6 +2936,8 @@ static int mmc_blk_alloc_rpmb_part(struct mmc_card *card,

  return 0;

+out_cdev_device_del:

• cdev_device_del(&rpmb->chrdev, &rpmb->dev);
  

out_put_device: put_device(&rpmb->dev); return ret; @@ -2770,6 +2946,7 @@ static int mmc_blk_alloc_rpmb_part(struct mmc_card *card, static void mmc_blk_remove_rpmb_part(struct mmc_rpmb_data *rpmb)

{

• rpmb_dev_unregister(rpmb->rdev);
  cdev_device_del(&rpmb->chrdev, &rpmb->dev);
  put_device(&rpmb->dev);
  

}

2.34.1

Hi Jens,

On Wed, 31 Jan 2024 at 23:14, Jens Wiklander jens.wiklander@linaro.org wrote:

Adds support in the OP-TEE drivers (both SMC and FF-A ABIs) to probe and use an RPMB device via the RPBM subsystem instead of passing the RPMB frames via tee-supplicant in user space. A fallback mechanism is kept to route RPMB frames via tee-supplicant if the RPMB subsystem isn't available.

The OP-TEE RPC ABI is extended to support iterating over all RPMB devices until one is found with the expected RPMB key already programmed.

Signed-off-by: Jens Wiklander jens.wiklander@linaro.org

drivers/tee/optee/core.c | 1 + drivers/tee/optee/ffa_abi.c | 2 + drivers/tee/optee/optee_private.h | 6 + drivers/tee/optee/optee_rpc_cmd.h | 33 +++++ drivers/tee/optee/rpc.c | 221 ++++++++++++++++++++++++++++++ drivers/tee/optee/smc_abi.c | 2 + 6 files changed, 265 insertions(+)

[snip]

#endif /*__OPTEE_RPC_CMD_H*/ diff --git a/drivers/tee/optee/rpc.c b/drivers/tee/optee/rpc.c index e69bc6380683..6fd6f99dafab 100644 --- a/drivers/tee/optee/rpc.c +++ b/drivers/tee/optee/rpc.c @@ -7,6 +7,7 @@

#include <linux/delay.h> #include <linux/i2c.h> +#include <linux/rpmb.h> #include <linux/slab.h> #include <linux/tee_drv.h> #include "optee_private.h" @@ -255,6 +256,217 @@ void optee_rpc_cmd_free_suppl(struct tee_context *ctx, struct tee_shm *shm) optee_supp_thrd_req(ctx, OPTEE_RPC_CMD_SHM_FREE, 1, &param); }

+static void handle_rpc_func_rpmb_probe_reset(struct tee_context *ctx,

•                                        struct optee *optee,
  

•                                        struct optee_msg_arg *arg)
  

+{

•   struct tee_param params[1];
  

•   if (!IS_ENABLED(CONFIG_RPMB)) {
  

•           handle_rpc_supp_cmd(ctx, optee, arg);
  

•           return;
  

•   }
  

•   if (arg->num_params != ARRAY_SIZE(params) ||
  

•       optee->ops->from_msg_param(optee, params, arg->num_params,
  

•                                  arg->params) ||
  

•       params[0].attr != TEE_IOCTL_PARAM_ATTR_TYPE_VALUE_OUTPUT) {
  

•           arg->ret = TEEC_ERROR_BAD_PARAMETERS;
  

•           return;
  

•   }
  

•   params[0].u.value.a = OPTEE_RPC_SHM_TYPE_KERNEL;
  

•   params[0].u.value.b = 0;
  

•   params[0].u.value.c = 0;
  

•   if (optee->ops->to_msg_param(optee, arg->params,
  

•                                arg->num_params, params)) {
  

•           arg->ret = TEEC_ERROR_BAD_PARAMETERS;
  

•           return;
  

•   }
  

•   mutex_lock(&optee->rpmb_dev_mutex);
  

•   rpmb_dev_put(optee->rpmb_dev);
  

•   optee->rpmb_dev = NULL;
  

•   mutex_unlock(&optee->rpmb_dev_mutex);
  

•   arg->ret = TEEC_SUCCESS;
  

+}

+static int rpc_rpmb_match(struct device *dev, const void *data) +{

•   return 1;
  

+}

+static void handle_rpc_func_rpmb_probe_next(struct tee_context *ctx,

•                                       struct optee *optee,
  

•                                       struct optee_msg_arg *arg)
  

+{

•   struct rpmb_dev *start_rdev;
  

•   struct rpmb_dev *rdev;
  

•   struct tee_param params[2];
  

•   void *buf;
  

•   if (!IS_ENABLED(CONFIG_RPMB)) {
  

•           handle_rpc_supp_cmd(ctx, optee, arg);
  

•           return;
  

•   }
  

•   if (arg->num_params != ARRAY_SIZE(params) ||
  

•       optee->ops->from_msg_param(optee, params, arg->num_params,
  

•                                  arg->params) ||
  

•       params[0].attr != TEE_IOCTL_PARAM_ATTR_TYPE_VALUE_OUTPUT ||
  

•       params[1].attr != TEE_IOCTL_PARAM_ATTR_TYPE_MEMREF_OUTPUT) {
  

•           arg->ret = TEEC_ERROR_BAD_PARAMETERS;
  

•           return;
  

•   }
  

•   buf = tee_shm_get_va(params[1].u.memref.shm,
  

•                        params[1].u.memref.shm_offs);
  

•   if (!buf) {
  

•           arg->ret = TEEC_ERROR_BAD_PARAMETERS;
  

•           return;
  

•   }
  

•   mutex_lock(&optee->rpmb_dev_mutex);
  

•   start_rdev = optee->rpmb_dev;
  

•   rdev = rpmb_dev_find_device(NULL, start_rdev, rpc_rpmb_match);
  

•   rpmb_dev_put(start_rdev);
  

•   optee->rpmb_dev = rdev;
  

•   mutex_unlock(&optee->rpmb_dev_mutex);
  

•   if (!rdev) {
  

•           arg->ret = TEEC_ERROR_ITEM_NOT_FOUND;
  

One of the major comments I have here is regarding how this implicit dependency on eMMC driver probe is met here. What if OP-TEE based fTPM/EFI client driver probes before eMMC driver?

-Sumit