[02/12] fpga: sec-mgr: enable secure updates

Message ID	20210517023200.52707-3-mdf@kernel.org (mailing list archive)
State	New
Headers	show Return-Path: <linux-fpga-owner@kernel.org> From: Moritz Fischer <mdf@kernel.org> To: gregkh@linuxfoundation.org Cc: linux-fpga@vger.kernel.org, moritzf@google.com, Moritz Fischer <mdf@kernel.org>, Russ Weight <russell.h.weight@intel.com>, Tom Rix <trix@redhat.com> Subject: [PATCH 02/12] fpga: sec-mgr: enable secure updates Date: Sun, 16 May 2021 19:31:50 -0700 Message-Id: <20210517023200.52707-3-mdf@kernel.org> In-Reply-To: <20210517023200.52707-1-mdf@kernel.org> References: <20210517023200.52707-1-mdf@kernel.org> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk
Series	FPGA Security Manager for 5.14 \| expand [00/12] FPGA Security Manager for 5.14 [01/12] fpga: sec-mgr: fpga security manager class driver [02/12] fpga: sec-mgr: enable secure updates [03/12] fpga: sec-mgr: expose sec-mgr update status [04/12] fpga: sec-mgr: expose sec-mgr update errors [05/12] fpga: sec-mgr: expose sec-mgr update size [06/12] fpga: sec-mgr: enable cancel of secure update [07/12] fpga: sec-mgr: expose hardware error info [08/12] fpga: m10bmc-sec: create max10 bmc secure update driver [09/12] fpga: m10bmc-sec: expose max10 flash update count [10/12] fpga: m10bmc-sec: expose max10 canceled keys in sysfs [11/12] fpga: m10bmc-sec: add max10 secure update functions [12/12] fpga: m10bmc-sec: add max10 get_hw_errinfo callback func

diff --git a/Documentation/ABI/testing/sysfs-class-fpga-sec-mgr b/Documentation/ABI/testing/sysfs-class-fpga-sec-mgr index 2498aef0ac51..36d1b6ba8d76 100644 --- a/Documentation/ABI/testing/sysfs-class-fpga-sec-mgr +++ b/Documentation/ABI/testing/sysfs-class-fpga-sec-mgr @@ -3,3 +3,16 @@ Date: June 2021 KernelVersion: 5.14 Contact: Russ Weight <russell.h.weight@intel.com> Description: Name of low level fpga security manager driver. + +What: /sys/class/fpga_sec_mgr/fpga_secX/update/filename +Date: June 2021 +KernelVersion: 5.14 +Contact: Russ Weight <russell.h.weight@intel.com> +Description: Write only. Write the filename of an image + file to this sysfs file to initiate a secure + update. The file must have an appropriate header + which, among other things, identifies the target + for the update. This mechanism is used to update + BMC images, BMC firmware, Static Region images, + and Root Entry Hashes, and to cancel Code Signing + Keys (CSK). diff --git a/drivers/fpga/fpga-sec-mgr.c b/drivers/fpga/fpga-sec-mgr.c index 468379e0c825..bfdb01d2de57 100644 --- a/drivers/fpga/fpga-sec-mgr.c +++ b/drivers/fpga/fpga-sec-mgr.c @@ -5,8 +5,11 @@ * Copyright (C) 2019-2020 Intel Corporation, Inc. */ +#include <linux/delay.h> +#include <linux/firmware.h> #include <linux/fpga/fpga-sec-mgr.h> #include <linux/idr.h> +#include <linux/kernel.h> #include <linux/module.h> #include <linux/slab.h> #include <linux/vmalloc.h> @@ -20,6 +23,132 @@ struct fpga_sec_mgr_devres { #define to_sec_mgr(d) container_of(d, struct fpga_sec_mgr, dev) +static void fpga_sec_dev_error(struct fpga_sec_mgr *smgr, + enum fpga_sec_err err_code) +{ + smgr->err_code = err_code; + smgr->sops->cancel(smgr); +} + +static void progress_complete(struct fpga_sec_mgr *smgr) +{ + mutex_lock(&smgr->lock); + smgr->progress = FPGA_SEC_PROG_IDLE; + complete_all(&smgr->update_done); + mutex_unlock(&smgr->lock); +} + +static void fpga_sec_mgr_update(struct work_struct *work) +{ + struct fpga_sec_mgr *smgr; + const struct firmware *fw; + enum fpga_sec_err ret; + u32 offset = 0; + + smgr = container_of(work, struct fpga_sec_mgr, work); + + get_device(&smgr->dev); + if (request_firmware(&fw, smgr->filename, &smgr->dev)) { + smgr->err_code = FPGA_SEC_ERR_FILE_READ; + goto idle_exit; + } + + smgr->data = fw->data; + smgr->remaining_size = fw->size; + + if (!try_module_get(smgr->dev.parent->driver->owner)) { + smgr->err_code = FPGA_SEC_ERR_BUSY; + goto release_fw_exit; + } + + smgr->progress = FPGA_SEC_PROG_PREPARING; + ret = smgr->sops->prepare(smgr); + if (ret != FPGA_SEC_ERR_NONE) { + fpga_sec_dev_error(smgr, ret); + goto modput_exit; + } + + smgr->progress = FPGA_SEC_PROG_WRITING; + while (smgr->remaining_size) { + ret = smgr->sops->write_blk(smgr, offset); + if (ret != FPGA_SEC_ERR_NONE) { + fpga_sec_dev_error(smgr, ret); + goto done; + } + + offset = fw->size - smgr->remaining_size; + } + + smgr->progress = FPGA_SEC_PROG_PROGRAMMING; + ret = smgr->sops->poll_complete(smgr); + if (ret != FPGA_SEC_ERR_NONE) + fpga_sec_dev_error(smgr, ret); + +done: + if (smgr->sops->cleanup) + smgr->sops->cleanup(smgr); + +modput_exit: + module_put(smgr->dev.parent->driver->owner); + +release_fw_exit: + smgr->data = NULL; + release_firmware(fw); + +idle_exit: + /* + * Note: smgr->remaining_size is left unmodified here to + * provide additional information on errors. It will be + * reinitialized when the next secure update begins. + */ + kfree(smgr->filename); + smgr->filename = NULL; + put_device(&smgr->dev); + progress_complete(smgr); +} + +static ssize_t filename_store(struct device *dev, struct device_attribute *attr, + const char *buf, size_t count) +{ + struct fpga_sec_mgr *smgr = to_sec_mgr(dev); + int ret = count; + + if (!count || count >= PATH_MAX) + return -EINVAL; + + mutex_lock(&smgr->lock); + if (smgr->driver_unload || smgr->progress != FPGA_SEC_PROG_IDLE) { + ret = -EBUSY; + goto unlock_exit; + } + + smgr->filename = kmemdup_nul(buf, count, GFP_KERNEL); + if (!smgr->filename) { + ret = -ENOMEM; + goto unlock_exit; + } + + smgr->err_code = FPGA_SEC_ERR_NONE; + smgr->progress = FPGA_SEC_PROG_READING; + reinit_completion(&smgr->update_done); + schedule_work(&smgr->work); + +unlock_exit: + mutex_unlock(&smgr->lock); + return ret; +} +static DEVICE_ATTR_WO(filename); + +static struct attribute *sec_mgr_update_attrs[] = { + &dev_attr_filename.attr, + NULL, +}; + +static struct attribute_group sec_mgr_update_attr_group = { + .name = "update", + .attrs = sec_mgr_update_attrs, +}; + static ssize_t name_show(struct device *dev, struct device_attribute *attr, char *buf) { @@ -40,6 +169,7 @@ static struct attribute_group sec_mgr_attr_group = { static const struct attribute_group *fpga_sec_mgr_attr_groups[] = { &sec_mgr_attr_group, + &sec_mgr_update_attr_group, NULL, }; @@ -65,6 +195,12 @@ fpga_sec_mgr_create(struct device *dev, const char *name, struct fpga_sec_mgr *smgr; int id, ret; + if (!sops || !sops->cancel || !sops->prepare || + !sops->write_blk || !sops->poll_complete) { + dev_err(dev, "Attempt to register without all required ops\n"); + return NULL; + } + if (!name || !strlen(name)) { dev_err(dev, "Attempt to register with no name!\n"); return NULL; @@ -83,6 +219,10 @@ fpga_sec_mgr_create(struct device *dev, const char *name, smgr->name = name; smgr->priv = priv; smgr->sops = sops; + smgr->err_code = FPGA_SEC_ERR_NONE; + smgr->progress = FPGA_SEC_PROG_IDLE; + init_completion(&smgr->update_done); + INIT_WORK(&smgr->work, fpga_sec_mgr_update); device_initialize(&smgr->dev); smgr->dev.class = fpga_sec_mgr_class; @@ -200,11 +340,31 @@ EXPORT_SYMBOL_GPL(fpga_sec_mgr_register); * * This function is intended for use in an FPGA security manager * driver's remove() function. + * + * For some devices, once the secure update has begun authentication + * the hardware cannot be signaled to stop, and the driver will not + * exit until the hardware signals completion. This could be 30+ + * minutes of waiting. The driver_unload flag enables a force-unload + * of the driver (e.g. modprobe -r) by signaling the parent driver to + * exit even if the hardware update is incomplete. The driver_unload + * flag also prevents new updates from starting once the unregister + * process has begun. */ void fpga_sec_mgr_unregister(struct fpga_sec_mgr *smgr) { dev_info(&smgr->dev, "%s %s\n", __func__, smgr->name); + mutex_lock(&smgr->lock); + smgr->driver_unload = true; + if (smgr->progress == FPGA_SEC_PROG_IDLE) { + mutex_unlock(&smgr->lock); + goto unregister; + } + + mutex_unlock(&smgr->lock); + wait_for_completion(&smgr->update_done); + +unregister: device_unregister(&smgr->dev); } EXPORT_SYMBOL_GPL(fpga_sec_mgr_unregister); diff --git a/include/linux/fpga/fpga-sec-mgr.h b/include/linux/fpga/fpga-sec-mgr.h index f85665b79b9d..978ab98ffac5 100644 --- a/include/linux/fpga/fpga-sec-mgr.h +++ b/include/linux/fpga/fpga-sec-mgr.h @@ -7,16 +7,56 @@ #ifndef _LINUX_FPGA_SEC_MGR_H #define _LINUX_FPGA_SEC_MGR_H +#include <linux/completion.h> #include <linux/device.h> #include <linux/mutex.h> #include <linux/types.h> struct fpga_sec_mgr; +enum fpga_sec_err { + FPGA_SEC_ERR_NONE, + FPGA_SEC_ERR_HW_ERROR, + FPGA_SEC_ERR_TIMEOUT, + FPGA_SEC_ERR_CANCELED, + FPGA_SEC_ERR_BUSY, + FPGA_SEC_ERR_INVALID_SIZE, + FPGA_SEC_ERR_RW_ERROR, + FPGA_SEC_ERR_WEAROUT, + FPGA_SEC_ERR_FILE_READ, + FPGA_SEC_ERR_MAX +}; + /** * struct fpga_sec_mgr_ops - device specific operations + * @prepare: Required: Prepare secure update + * @write_blk: Required: Write a block of data + * @poll_complete: Required: Check for the completion of the + * HW authentication/programming process. This + * function should check for smgr->driver_unload + * and abort with FPGA_SEC_ERR_CANCELED when true. + * @cancel: Required: Signal HW to cancel update + * @cleanup: Optional: Complements the prepare() + * function and is called at the completion + * of the update, whether success or failure, + * if the prepare function succeeded. */ struct fpga_sec_mgr_ops { + enum fpga_sec_err (*prepare)(struct fpga_sec_mgr *smgr); + enum fpga_sec_err (*write_blk)(struct fpga_sec_mgr *smgr, u32 offset); + enum fpga_sec_err (*poll_complete)(struct fpga_sec_mgr *smgr); + enum fpga_sec_err (*cancel)(struct fpga_sec_mgr *smgr); + void (*cleanup)(struct fpga_sec_mgr *smgr); +}; + +/* Update progress codes */ +enum fpga_sec_prog { + FPGA_SEC_PROG_IDLE, + FPGA_SEC_PROG_READING, + FPGA_SEC_PROG_PREPARING, + FPGA_SEC_PROG_WRITING, + FPGA_SEC_PROG_PROGRAMMING, + FPGA_SEC_PROG_MAX }; struct fpga_sec_mgr { @@ -24,6 +64,14 @@ struct fpga_sec_mgr { struct device dev; const struct fpga_sec_mgr_ops *sops; struct mutex lock; /* protect data structure contents */ + struct work_struct work; + struct completion update_done; + char *filename; + const u8 *data; /* pointer to update data */ + u32 remaining_size; /* size remaining to transfer */ + enum fpga_sec_prog progress; + enum fpga_sec_err err_code; /* security manager error code */ + bool driver_unload; void *priv; };

[02/12] fpga: sec-mgr: enable secure updates

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