On Thu, Feb 1, 2024 at 7:04 AM Randy Dunlap <rdunlap@xxxxxxxxxxxxx> 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@xxxxxxxxx>
> > Signed-off-by: Alex Bennée <alex.bennee@xxxxxxxxxx>
> > Signed-off-by: Shyam Saini <shyamsaini@xxxxxxxxxxxxxxxxxxx>
> > Signed-off-by: Jens Wiklander <jens.wiklander@xxxxxxxxxx>
> > ---
> > 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
