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- // SPDX-License-Identifier: GPL-2.0+
- /*
- * File interface for UEFI variables
- *
- * Copyright (c) 2020, Heinrich Schuchardt
- */
- #define LOG_CATEGORY LOGC_EFI
- #include <common.h>
- #include <charset.h>
- #include <fs.h>
- #include <log.h>
- #include <malloc.h>
- #include <mapmem.h>
- #include <efi_loader.h>
- #include <efi_variable.h>
- #include <u-boot/crc.h>
- #define PART_STR_LEN 10
- /**
- * efi_set_blk_dev_to_system_partition() - select EFI system partition
- *
- * Set the EFI system partition as current block device.
- *
- * Return: status code
- */
- static efi_status_t __maybe_unused efi_set_blk_dev_to_system_partition(void)
- {
- char part_str[PART_STR_LEN];
- int r;
- if (!efi_system_partition.if_type) {
- log_err("No EFI system partition\n");
- return EFI_DEVICE_ERROR;
- }
- snprintf(part_str, PART_STR_LEN, "%u:%u",
- efi_system_partition.devnum, efi_system_partition.part);
- r = fs_set_blk_dev(blk_get_if_type_name(efi_system_partition.if_type),
- part_str, FS_TYPE_ANY);
- if (r) {
- log_err("Cannot read EFI system partition\n");
- return EFI_DEVICE_ERROR;
- }
- return EFI_SUCCESS;
- }
- efi_status_t __maybe_unused efi_var_collect(struct efi_var_file **bufp, loff_t *lenp,
- u32 check_attr_mask)
- {
- size_t len = EFI_VAR_BUF_SIZE;
- struct efi_var_file *buf;
- struct efi_var_entry *var, *old_var;
- size_t old_var_name_length = 2;
- *bufp = NULL; /* Avoid double free() */
- buf = calloc(1, len);
- if (!buf)
- return EFI_OUT_OF_RESOURCES;
- var = buf->var;
- old_var = var;
- for (;;) {
- efi_uintn_t data_length, var_name_length;
- u8 *data;
- efi_status_t ret;
- if ((uintptr_t)buf + len <=
- (uintptr_t)var->name + old_var_name_length)
- return EFI_BUFFER_TOO_SMALL;
- var_name_length = (uintptr_t)buf + len - (uintptr_t)var->name;
- memcpy(var->name, old_var->name, old_var_name_length);
- guidcpy(&var->guid, &old_var->guid);
- ret = efi_get_next_variable_name_int(
- &var_name_length, var->name, &var->guid);
- if (ret == EFI_NOT_FOUND)
- break;
- if (ret != EFI_SUCCESS) {
- free(buf);
- return ret;
- }
- old_var_name_length = var_name_length;
- old_var = var;
- data = (u8 *)var->name + old_var_name_length;
- data_length = (uintptr_t)buf + len - (uintptr_t)data;
- ret = efi_get_variable_int(var->name, &var->guid,
- &var->attr, &data_length, data,
- &var->time);
- if (ret != EFI_SUCCESS) {
- free(buf);
- return ret;
- }
- if ((var->attr & check_attr_mask) == check_attr_mask) {
- var->length = data_length;
- var = (struct efi_var_entry *)ALIGN((uintptr_t)data + data_length, 8);
- }
- }
- buf->reserved = 0;
- buf->magic = EFI_VAR_FILE_MAGIC;
- len = (uintptr_t)var - (uintptr_t)buf;
- buf->crc32 = crc32(0, (u8 *)buf->var,
- len - sizeof(struct efi_var_file));
- buf->length = len;
- *bufp = buf;
- *lenp = len;
- return EFI_SUCCESS;
- }
- /**
- * 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)
- {
- #ifdef CONFIG_EFI_VARIABLE_FILE_STORE
- efi_status_t ret;
- struct efi_var_file *buf;
- loff_t len;
- loff_t actlen;
- int r;
- ret = efi_var_collect(&buf, &len, EFI_VARIABLE_NON_VOLATILE);
- if (ret != EFI_SUCCESS)
- goto error;
- ret = efi_set_blk_dev_to_system_partition();
- if (ret != EFI_SUCCESS)
- goto error;
- r = fs_write(EFI_VAR_FILE_NAME, map_to_sysmem(buf), 0, len, &actlen);
- if (r || len != actlen)
- ret = EFI_DEVICE_ERROR;
- error:
- if (ret != EFI_SUCCESS)
- log_err("Failed to persist EFI variables\n");
- free(buf);
- return ret;
- #else
- return EFI_SUCCESS;
- #endif
- }
- efi_status_t efi_var_restore(struct efi_var_file *buf)
- {
- struct efi_var_entry *var, *last_var;
- efi_status_t ret;
- if (buf->reserved || buf->magic != EFI_VAR_FILE_MAGIC ||
- buf->crc32 != crc32(0, (u8 *)buf->var,
- buf->length - sizeof(struct efi_var_file))) {
- log_err("Invalid EFI variables file\n");
- return EFI_INVALID_PARAMETER;
- }
- var = buf->var;
- last_var = (struct efi_var_entry *)((u8 *)buf + buf->length);
- while (var < last_var) {
- u16 *data = var->name + u16_strlen(var->name) + 1;
- if (var->attr & EFI_VARIABLE_NON_VOLATILE && var->length) {
- ret = efi_var_mem_ins(var->name, &var->guid, var->attr,
- var->length, data, 0, NULL,
- var->time);
- if (ret != EFI_SUCCESS)
- log_err("Failed to set EFI variable %ls\n",
- var->name);
- }
- var = (struct efi_var_entry *)
- ALIGN((uintptr_t)data + var->length, 8);
- }
- return EFI_SUCCESS;
- }
- /**
- * 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)
- {
- #ifdef CONFIG_EFI_VARIABLE_FILE_STORE
- struct efi_var_file *buf;
- loff_t len;
- efi_status_t ret;
- int r;
- buf = calloc(1, EFI_VAR_BUF_SIZE);
- if (!buf) {
- log_err("Out of memory\n");
- return EFI_OUT_OF_RESOURCES;
- }
- ret = efi_set_blk_dev_to_system_partition();
- if (ret != EFI_SUCCESS)
- goto error;
- r = fs_read(EFI_VAR_FILE_NAME, map_to_sysmem(buf), 0, EFI_VAR_BUF_SIZE,
- &len);
- if (r || len < sizeof(struct efi_var_file)) {
- log_err("Failed to load EFI variables\n");
- goto error;
- }
- if (buf->length != len || efi_var_restore(buf) != EFI_SUCCESS)
- log_err("Invalid EFI variables file\n");
- error:
- free(buf);
- #endif
- return EFI_SUCCESS;
- }
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