/* SPDX-License-Identifier: GPL-2.0+ */ /* * Copyright (c) 2020, Heinrich Schuchardt */ #ifndef _EFI_VARIABLE_H #define _EFI_VARIABLE_H #include #define EFI_VARIABLE_READ_ONLY BIT(31) enum efi_auth_var_type { EFI_AUTH_VAR_NONE = 0, EFI_AUTH_VAR_PK, EFI_AUTH_VAR_KEK, EFI_AUTH_VAR_DB, EFI_AUTH_VAR_DBX, EFI_AUTH_VAR_DBT, EFI_AUTH_VAR_DBR, }; /** * efi_get_variable() - retrieve value of a UEFI variable * * @variable_name: name of the variable * @vendor: vendor GUID * @attributes: attributes of the variable * @data_size: size of the buffer to which the variable value is copied * @data: buffer to which the variable value is copied * @timep: authentication time (seconds since start of epoch) * Return: status code */ efi_status_t efi_get_variable_int(u16 *variable_name, const efi_guid_t *vendor, u32 *attributes, efi_uintn_t *data_size, void *data, u64 *timep); /** * efi_set_variable() - set value of a UEFI variable * * @variable_name: name of the variable * @vendor: vendor GUID * @attributes: attributes of the variable * @data_size: size of the buffer with the variable value * @data: buffer with the variable value * @ro_check: check the read only read only bit in attributes * Return: status code */ efi_status_t efi_set_variable_int(u16 *variable_name, const efi_guid_t *vendor, u32 attributes, efi_uintn_t data_size, const void *data, bool ro_check); /** * efi_get_next_variable_name_int() - enumerate the current variable names * * @variable_name_size: size of variable_name buffer in byte * @variable_name: name of uefi variable's name in u16 * @vendor: vendor's guid * * See the Unified Extensible Firmware Interface (UEFI) specification for * details. * * Return: status code */ efi_status_t efi_get_next_variable_name_int(efi_uintn_t *variable_name_size, u16 *variable_name, efi_guid_t *vendor); /** * efi_query_variable_info_int() - get information about EFI variables * * This function implements the QueryVariableInfo() runtime service. * * See the Unified Extensible Firmware Interface (UEFI) specification for * details. * * @attributes: bitmask to select variables to be * queried * @maximum_variable_storage_size: maximum size of storage area for the * selected variable types * @remaining_variable_storage_size: remaining size of storage are for the * selected variable types * @maximum_variable_size: maximum size of a variable of the * selected type * Returns: status code */ efi_status_t efi_query_variable_info_int(u32 attributes, u64 *maximum_variable_storage_size, u64 *remaining_variable_storage_size, u64 *maximum_variable_size); #define EFI_VAR_FILE_NAME "ubootefi.var" #define EFI_VAR_BUF_SIZE CONFIG_EFI_VAR_BUF_SIZE /* * This constant identifies the file format for storing UEFI variables in * struct efi_var_file. */ #define EFI_VAR_FILE_MAGIC 0x0161566966456255 /* UbEfiVa, version 1 */ /** * struct efi_var_entry - UEFI variable file entry * * @length: length of enty, multiple of 8 * @attr: variable attributes * @time: authentication time (seconds since start of epoch) * @guid: vendor GUID * @name: UTF16 variable name */ struct efi_var_entry { u32 length; u32 attr; u64 time; efi_guid_t guid; u16 name[]; }; /** * struct efi_var_file - file for storing UEFI variables * * @reserved: unused, may be overwritten by memory probing * @magic: identifies file format, takes value %EFI_VAR_FILE_MAGIC * @length: length including header * @crc32: CRC32 without header * @var: variables */ struct efi_var_file { u64 reserved; u64 magic; u32 length; u32 crc32; struct efi_var_entry var[]; }; /** * efi_var_to_file() - save non-volatile variables as file * * File ubootefi.var is created on the EFI system partion. * * Return: status code */ efi_status_t efi_var_to_file(void); /** * efi_var_collect() - collect variables in buffer * * A buffer is allocated and filled with variables in a format ready to be * written to disk. * * @bufp: pointer to pointer of buffer with collected variables * @lenp: pointer to length of buffer * @check_attr_mask: bitmask with required attributes of variables to be collected. * variables are only collected if all of the required * attributes are set. * Return: status code */ efi_status_t __maybe_unused efi_var_collect(struct efi_var_file **bufp, loff_t *lenp, u32 check_attr_mask); /** * efi_var_restore() - restore EFI variables from buffer * * @buf: buffer * Return: status code */ efi_status_t efi_var_restore(struct efi_var_file *buf); /** * efi_var_from_file() - read variables from file * * File ubootefi.var is read from the EFI system partitions and the variables * stored in the file are created. * * In case the file does not exist yet or a variable cannot be set EFI_SUCCESS * is returned. * * Return: status code */ efi_status_t efi_var_from_file(void); /** * efi_var_mem_init() - set-up variable list * * Return: status code */ efi_status_t efi_var_mem_init(void); /** * efi_var_mem_find() - find a variable in the list * * @guid: GUID of the variable * @name: name of the variable * @next: on exit pointer to the next variable after the found one * Return: found variable */ struct efi_var_entry *efi_var_mem_find(const efi_guid_t *guid, const u16 *name, struct efi_var_entry **next); /** * efi_var_mem_del() - delete a variable from the list of variables * * @var: variable to delete */ void efi_var_mem_del(struct efi_var_entry *var); /** * efi_var_mem_ins() - append a variable to the list of variables * * The variable is appended without checking if a variable of the same name * already exists. The two data buffers are concatenated. * * @variable_name: variable name * @vendor: GUID * @attributes: variable attributes * @size1: size of the first data buffer * @data1: first data buffer * @size2: size of the second data field * @data2: second data buffer * @time: time of authentication (as seconds since start of epoch) * Result: status code */ efi_status_t efi_var_mem_ins(u16 *variable_name, const efi_guid_t *vendor, u32 attributes, const efi_uintn_t size1, const void *data1, const efi_uintn_t size2, const void *data2, const u64 time); /** * efi_var_mem_free() - determine free memory for variables * * Return: maximum data size plus variable name size */ u64 efi_var_mem_free(void); /** * efi_init_secure_state - initialize secure boot state * * Return: status code */ efi_status_t efi_init_secure_state(void); /** * efi_auth_var_get_type() - convert variable name and guid to enum * * @name: name of UEFI variable * @guid: guid of UEFI variable * Return: identifier for authentication related variables */ enum efi_auth_var_type efi_auth_var_get_type(u16 *name, const efi_guid_t *guid); /** * efi_get_next_variable_name_mem() - Runtime common code across efi variable * implementations for GetNextVariable() * from the cached memory copy * @variable_name_size: size of variable_name buffer in byte * @variable_name: name of uefi variable's name in u16 * @vendor: vendor's guid * * Return: status code */ efi_status_t __efi_runtime efi_get_next_variable_name_mem(efi_uintn_t *variable_name_size, u16 *variable_name, efi_guid_t *vendor); /** * efi_get_variable_mem() - Runtime common code across efi variable * implementations for GetVariable() from * the cached memory copy * * @variable_name: name of the variable * @vendor: vendor GUID * @attributes: attributes of the variable * @data_size: size of the buffer to which the variable value is copied * @data: buffer to which the variable value is copied * @timep: authentication time (seconds since start of epoch) * Return: status code */ efi_status_t __efi_runtime efi_get_variable_mem(u16 *variable_name, const efi_guid_t *vendor, u32 *attributes, efi_uintn_t *data_size, void *data, u64 *timep); /** * efi_get_variable_runtime() - runtime implementation of GetVariable() * * @variable_name: name of the variable * @guid: vendor GUID * @attributes: attributes of the variable * @data_size: size of the buffer to which the variable value is copied * @data: buffer to which the variable value is copied * Return: status code */ efi_status_t __efi_runtime EFIAPI efi_get_variable_runtime(u16 *variable_name, const efi_guid_t *guid, u32 *attributes, efi_uintn_t *data_size, void *data); /** * efi_get_next_variable_name_runtime() - runtime implementation of * GetNextVariable() * * @variable_name_size: size of variable_name buffer in byte * @variable_name: name of uefi variable's name in u16 * @guid: vendor's guid * Return: status code */ efi_status_t __efi_runtime EFIAPI efi_get_next_variable_name_runtime(efi_uintn_t *variable_name_size, u16 *variable_name, efi_guid_t *guid); /** * efi_var_buf_update() - udpate memory buffer for variables * * @var_buf: source buffer * * This function copies to the memory buffer for UEFI variables. Call this * function in ExitBootServices() if memory backed variables are only used * at runtime to fill the buffer. */ void efi_var_buf_update(struct efi_var_file *var_buf); #endif