[RESEND RFC PATCH 03/10] FWU: Add metadata structure and functions for accessing metadata
Heinrich Schuchardt
xypron.glpk at gmx.de
Tue Nov 30 13:57:52 CET 2021
On 11/25/21 08:12, Sughosh Ganu wrote:
> In the FWU Multi Bank Update feature, the information about the
> updatable images is stored as part of the metadata, which is stored on
> a dedicated partition. Add the metadata structure, and functions to
> access the metadata. These are generic API's, and implementations can
> be added based on parameters like how the metadata partition is
> accessed and what type of storage device houses the metadata.
>
> Signed-off-by: Sughosh Ganu <sughosh.ganu at linaro.org>
> ---
> include/fwu_metadata.h | 125 +++++++++++++++
> lib/fwu_updates/fwu_metadata.c | 275 +++++++++++++++++++++++++++++++++
> 2 files changed, 400 insertions(+)
> create mode 100644 include/fwu_metadata.h
> create mode 100644 lib/fwu_updates/fwu_metadata.c
>
> diff --git a/include/fwu_metadata.h b/include/fwu_metadata.h
> new file mode 100644
> index 0000000000..e692ef7506
> --- /dev/null
> +++ b/include/fwu_metadata.h
> @@ -0,0 +1,125 @@
> +/* SPDX-License-Identifier: GPL-2.0+ */
> +/*
> + * Copyright (c) 2021, Linaro Limited
> + */
> +
> +#if !defined _FWU_METADATA_H_
> +#define _FWU_METADATA_H_
> +
> +#include <blk.h>
> +#include <efi.h>
> +#include <uuid.h>
> +
> +#include <linux/types.h>
> +
> +/**
> + * struct fwu_image_bank_info - firmware image information
> + * @image_uuid: Guid value of the image in this bank
> + * @accepted: Acceptance status of the image
> + * @reserved: Reserved
> + *
> + * The structure contains image specific fields which are
> + * used to identify the image and to specify the image's
> + * acceptance status
> + */
> +struct fwu_image_bank_info {
> + efi_guid_t image_uuid;
> + u32 accepted;
> + u32 reserved;
> +};
> +
> +/**
> + * struct fwu_image_entry - information for a particular type of image
> + * @image_type_uuid: Guid value for identifying the image type
> + * @location_uuid: Guid of the storage volume where the image is located
> + * @img_bank_info: Array containing properties of images
> + *
> + * This structure contains information on various types of updatable
> + * firmware images. Each image type then contains an array of image
> + * information per bank.
> + */
> +struct fwu_image_entry {
> + efi_guid_t image_type_uuid;
> + efi_guid_t location_uuid;
> + struct fwu_image_bank_info img_bank_info[CONFIG_FWU_NUM_BANKS];
> +};
> +
> +/**
> + * struct fwu_metadata - Metadata structure for multi-bank updates
> + * @crc32: crc32 value for the metadata
> + * @version: Metadata version
> + * @active_index: Index of the bank currently used for booting images
> + * @previous_active_inde: Index of the bank used before the current bank
> + * being used for booting
> + * @img_entry: Array of information on various firmware images that can
> + * be updated
> + *
> + * This structure is used to store all the needed information for performing
> + * multi bank updates on the platform. This contains info on the bank being
> + * used to boot along with the information needed for identification of
> + * individual images
> + */
> +struct fwu_metadata {
> + u32 crc32;
> + u32 version;
> + u32 active_index;
> + u32 previous_active_index;
> +
> + struct fwu_image_entry img_entry[CONFIG_FWU_NUM_IMAGES_PER_BANK];
> +};
> +
> +/**
> + * @get_active_index: get the current active_index value
> + * @update_active_index: update the active_index value
> + * @fill_partition_guid_array: fill the array with guid values of the
> + * partitions found on the storage media
> + * @get_image_alt_num: get the alt number to be used for the image
> + * @metadata_check: check the validity of the metadata partitions
> + * @revert_boot_index: set the active_index to previous_active_index
> + * @set_accept_image: set the accepted bit for the image
> + * @clear_accept_image: clear the accepted bit for the image
> + * @get_metadata() - Get a metadata copy
> + */
> +struct fwu_metadata_ops {
> + int (*get_active_index)(u32 *active_idx);
> +
> + int (*update_active_index)(u32 active_idx);
> +
> + int (*fill_partition_guid_array)(efi_guid_t **part_guid_arr,
> + u32 *nparts);
> +
> + int (*get_image_alt_num)(efi_guid_t image_type_id, u32 update_bank,
> + int *alt_num);
> +
> + int (*metadata_check)(void);
> +
> + int (*revert_boot_index)(u32 *active_idx);
> +
> + int (*set_accept_image)(efi_guid_t *img_type_id);
> +
> + int (*clear_accept_image)(efi_guid_t *img_type_id, u32 bank);
> +
> + int (*get_metadata)(struct fwu_metadata **metadata);
> +};
> +
> +#define FWU_METADATA_GUID \
> + EFI_GUID(0x8a7a84a0, 0x8387, 0x40f6, 0xab, 0x41, \
> + 0xa8, 0xb9, 0xa5, 0xa6, 0x0d, 0x23)
> +
> +#define FWU_METADATA_VERSION 0x1
> +
> +extern struct fwu_metadata_ops fwu_gpt_blk_ops;
> +
> +struct fwu_metadata_ops *get_plat_fwu_metadata_ops(void);
> +int fwu_get_active_index(u32 *active_idx);
> +int fwu_update_active_index(u32 active_idx);
> +int fwu_fill_partition_guid_array(efi_guid_t **part_guid_arr, u32 *nparts);
> +int fwu_get_image_alt_num(efi_guid_t image_type_id, u32 update_bank,
> + int *alt_num);
> +int fwu_metadata_check(void);
> +int fwu_revert_boot_index(u32 *active_idx);
> +int fwu_accept_image(efi_guid_t *img_type_id);
> +int fwu_clear_accept_image(efi_guid_t *img_type_id, u32 bank);
> +int fwu_get_metadata(struct fwu_metadata **metadata);
> +
> +#endif /* _FWU_METADATA_H_ */
> diff --git a/lib/fwu_updates/fwu_metadata.c b/lib/fwu_updates/fwu_metadata.c
> new file mode 100644
> index 0000000000..ebc3eaa04a
> --- /dev/null
> +++ b/lib/fwu_updates/fwu_metadata.c
> @@ -0,0 +1,275 @@
> +// SPDX-License-Identifier: GPL-2.0+
> +/*
> + * Copyright (c) 2021, Linaro Limited
> + */
> +
> +#include <fwu_metadata.h>
> +
> +#include <linux/errno.h>
> +#include <linux/types.h>
> +
> +static inline struct fwu_metadata_ops *get_fwu_metadata_ops(void)
> +{
> + return get_plat_fwu_metadata_ops();
> +}
> +
> +/**
> + * fwu_get_active_index() - Get active_index from the metadata
> + * @active_idx: active_index value to be read
> + *
> + * Read the active_index field from the metadata and place it in
> + * the variable pointed to be the function argument.
> + *
> + * Return: 0 if OK, -ve on error
> + *
> + */
> +int fwu_get_active_index(u32 *active_idx)
> +{
> + struct fwu_metadata_ops *ops;
> +
> + ops = get_fwu_metadata_ops();
> + if (!ops) {
> + log_err("Unable to get fwu ops\n");
> + return -EPROTONOSUPPORT;
> + }
> +
> + if (!ops->get_active_index) {
> + log_err("get_active_index() method not defined for the platform\n");
> + return -ENOSYS;
> + }
> +
> + return ops->get_active_index(active_idx);
> +}
> +
> +/**
> + * fwu_update_active_index() - Update active_index from the metadata
> + * @active_idx: active_index value to be updated
> + *
> + * Update the active_index field in the metadata
> + *
> + * Return: 0 if OK, -ve on error
> + *
> + */
> +int fwu_update_active_index(u32 active_idx)
> +{
> + struct fwu_metadata_ops *ops;
> +
> + ops = get_fwu_metadata_ops();
> + if (!ops) {
> + log_err("Unable to get fwu ops\n");
> + return -EPROTONOSUPPORT;
> + }
> +
> + if (!ops->update_active_index) {
> + log_err("update_active_index() method not defined for the platform\n");
> + return -ENOSYS;
> + }
> +
> + return ops->update_active_index(active_idx);
> +}
> +
> +/**
> + * fwu_fill_partition_guid_array() - Fill the part_guid_arr array with the guid's of
> + * the partitions
> + * @part_guid_arr: array of partition guid's
> + * @nparts: Number of gpt partitions on the device
> + *
> + * Get the information on the partition guid's, filling the array with the guid
> + * values and also the number of partitions.
> + *
> + * Return: 0 if OK, -ve on error
> + *
> + */
> +int fwu_fill_partition_guid_array(efi_guid_t **part_guid_arr, u32 *nparts)
> +{
> + struct fwu_metadata_ops *ops;
> +
> + ops = get_fwu_metadata_ops();
> + if (!ops) {
> + log_err("Unable to get fwu ops\n");
> + return -EPROTONOSUPPORT;
> + }
> +
> + if (!ops->fill_partition_guid_array) {
> + log_err("fill_partition_guid_array() method not defined for the platform\n");
> + return -ENOSYS;
> + }
> +
> + return ops->fill_partition_guid_array(part_guid_arr, nparts);
> +}
> +
> +/**
> + * fwu_get_image_alt_num() - Get the dfu alt number to be used for capsule update
> + * @image_type_id: image guid as passed in the capsule
> + * @update_bank: Bank to which the update is to be made
> + * @alt_num: The alt_num for the image
> + *
> + * Based on the guid value passed in the capsule, along with the bank to which the
> + * image needs to be updated, get the dfu alt number which will be used for the
> + * capsule update
> + *
> + * Return: 0 if OK, -ve on error
> + *
> + */
> +int fwu_get_image_alt_num(efi_guid_t image_type_id, u32 update_bank,
> + int *alt_num)
> +{
> + struct fwu_metadata_ops *ops;
The metadata is an untrusted information source and hence MUST NOT be
used to map the image_type_id to the DFU alt_number. Don't invite for an
denial of service attack.
The signed capsule would be a good place for storing the DFU mapping.
Best regards
Heinrich
> +
> + ops = get_fwu_metadata_ops();
> + if (!ops) {
> + log_err("Unable to get fwu ops\n");
> + return -EPROTONOSUPPORT;
> + }
> +
> + if (!ops->get_image_alt_num) {
> + log_err("get_image_alt_num() method not defined for the platform\n");
> + return -ENOSYS;
> + }
> +
> + return ops->get_image_alt_num(image_type_id, update_bank, alt_num);
> +}
> +
> +/**
> + * fwu_metadata_check() - Check if the metadata is valid
> + *
> + * Validate both copies of metadata. If one of the copies
> + * has gone bad, restore it from the other bad copy.
> + *
> + * Return: 0 if OK, -ve on error
> + *
> + */
> +int fwu_metadata_check(void)
> +{
> + struct fwu_metadata_ops *ops;
> +
> + ops = get_fwu_metadata_ops();
> + if (!ops) {
> + log_err("Unable to get fwu ops\n");
> + return -EPROTONOSUPPORT;
> + }
> +
> + if (!ops->metadata_check) {
> + log_err("metadata_check() method not defined for the platform\n");
> + return -ENOSYS;
> + }
> +
> + return ops->metadata_check();
> +}
> +
> +/**
> + * fwu_revert_boot_index() - Revert the active index in the metadata
> + * @active_idx: Value of the updated active_index
> + *
> + * Revert the active_index value in the metadata, by swapping the values
> + * of active_index and previous_active_index in both copies of the
> + * metadata.
> + *
> + * Return: 0 if OK, -ve on error
> + *
> + */
> +int fwu_revert_boot_index(u32 *active_idx)
> +{
> + struct fwu_metadata_ops *ops;
> +
> + ops = get_fwu_metadata_ops();
> + if (!ops) {
> + log_err("Unable to get fwu ops\n");
> + return -EPROTONOSUPPORT;
> + }
> +
> + if (!ops->revert_boot_index) {
> + log_err("revert_boot_index() method not defined for the platform\n");
> + return -ENOSYS;
> + }
> +
> + return ops->revert_boot_index(active_idx);
> +}
> +
> +/**
> + * fwu_accept_image() - Set the Acceptance bit for the image
> + * @img_type_id: Guid of the image type for which the accepted bit is to be
> + * cleared
> + *
> + * Set the accepted bit for the image specified by the img_guid parameter. This
> + * indicates acceptance of image for subsequent boots by some governing component
> + * like OS(or firmware).
> + *
> + * Return: 0 if OK, -ve on error
> + *
> + */
> +int fwu_accept_image(efi_guid_t *img_type_id)
> +{
> + struct fwu_metadata_ops *ops;
> +
> + ops = get_fwu_metadata_ops();
> + if (!ops) {
> + log_err("Unable to get fwu ops\n");
> + return -EPROTONOSUPPORT;
> + }
> +
> + if (!ops->set_accept_image) {
> + log_err("set_accept_image() method not defined for the platform\n");
> + return -ENOSYS;
> + }
> +
> + return ops->set_accept_image(img_type_id);
> +}
> +
> +/**
> + * fwu_clear_accept_image() - Clear the Acceptance bit for the image
> + * @img_type_id: Guid of the image type for which the accepted bit is to be
> + * cleared
> + *
> + * Clear the accepted bit for the image type specified by the img_type_id parameter.
> + * This function is called after the image has been updated. The accepted bit is
> + * cleared to be set subsequently after passing the image acceptance criteria, by
> + * either the OS(or firmware)
> + *
> + * Return: 0 if OK, -ve on error
> + *
> + */
> +int fwu_clear_accept_image(efi_guid_t *img_type_id, u32 bank)
> +{
> + struct fwu_metadata_ops *ops;
> +
> + ops = get_fwu_metadata_ops();
> + if (!ops) {
> + log_err("Unable to get fwu ops\n");
> + return -EPROTONOSUPPORT;
> + }
> +
> + if (!ops->clear_accept_image) {
> + log_err("clear_accept_image() method not defined for the platform\n");
> + return -ENOSYS;
> + }
> +
> + return ops->clear_accept_image(img_type_id, bank);
> +}
> +
> +/**
> + * fwu_get_metadata() - Get a metadata copy
> + * @metadata: Copy of the metadata
> + *
> + * Get a valid copy of the metadata.
> + *
> + * Return: 0 if OK, -ve on error
> + *
> + */
> +int fwu_get_metadata(struct fwu_metadata **metadata)
> +{
> + struct fwu_metadata_ops *ops;
> +
> + ops = get_fwu_metadata_ops();
> + if (!ops) {
> + log_err("Unable to get fwu ops\n");
> + return -EPROTONOSUPPORT;
> + }
> +
> + if (!ops->get_metadata) {
> + log_err("get_metadata() method not defined for the platform\n");
> + return -ENOSYS;
> + }
> +
> + return ops->get_metadata(metadata);
> +}
>
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