// SPDX-License-Identifier: GPL-2.0+ /* * EFI boot manager * * Copyright (c) 2017 Rob Clark */ #define LOG_CATEGORY LOGC_EFI #include #include #include #include #include #include #include static const struct efi_boot_services *bs; static const struct efi_runtime_services *rs; /* * bootmgr implements the logic of trying to find a payload to boot * based on the BootOrder + BootXXXX variables, and then loading it. * * TODO detecting a special key held (f9?) and displaying a boot menu * like you would get on a PC would be clever. * * TODO if we had a way to write and persist variables after the OS * has started, we'd also want to check OsIndications to see if we * should do normal or recovery boot. */ /** * efi_set_load_options() - set the load options of a loaded image * * @handle: the image handle * @load_options_size: size of load options * @load_options: pointer to load options * Return: status code */ efi_status_t efi_set_load_options(efi_handle_t handle, efi_uintn_t load_options_size, void *load_options) { struct efi_loaded_image *loaded_image_info; efi_status_t ret; ret = EFI_CALL(systab.boottime->open_protocol( handle, &efi_guid_loaded_image, (void **)&loaded_image_info, efi_root, NULL, EFI_OPEN_PROTOCOL_BY_HANDLE_PROTOCOL)); if (ret != EFI_SUCCESS) return EFI_INVALID_PARAMETER; loaded_image_info->load_options = load_options; loaded_image_info->load_options_size = load_options_size; return EFI_CALL(systab.boottime->close_protocol(handle, &efi_guid_loaded_image, efi_root, NULL)); } /** * efi_deserialize_load_option() - parse serialized data * * Parse serialized data describing a load option and transform it to the * efi_load_option structure. * * @lo: pointer to target * @data: serialized data * @size: size of the load option, on return size of the optional data * Return: status code */ efi_status_t efi_deserialize_load_option(struct efi_load_option *lo, u8 *data, efi_uintn_t *size) { efi_uintn_t len; len = sizeof(u32); if (*size < len + 2 * sizeof(u16)) return EFI_INVALID_PARAMETER; lo->attributes = get_unaligned_le32(data); data += len; *size -= len; len = sizeof(u16); lo->file_path_length = get_unaligned_le16(data); data += len; *size -= len; lo->label = (u16 *)data; len = u16_strnlen(lo->label, *size / sizeof(u16) - 1); if (lo->label[len]) return EFI_INVALID_PARAMETER; len = (len + 1) * sizeof(u16); if (*size < len) return EFI_INVALID_PARAMETER; data += len; *size -= len; len = lo->file_path_length; if (*size < len) return EFI_INVALID_PARAMETER; lo->file_path = (struct efi_device_path *)data; if (efi_dp_check_length(lo->file_path, len) < 0) return EFI_INVALID_PARAMETER; data += len; *size -= len; lo->optional_data = data; return EFI_SUCCESS; } /** * efi_serialize_load_option() - serialize load option * * Serialize efi_load_option structure into byte stream for BootXXXX. * * @data: buffer for serialized data * @lo: load option * Return: size of allocated buffer */ unsigned long efi_serialize_load_option(struct efi_load_option *lo, u8 **data) { unsigned long label_len; unsigned long size; u8 *p; label_len = (u16_strlen(lo->label) + 1) * sizeof(u16); /* total size */ size = sizeof(lo->attributes); size += sizeof(lo->file_path_length); size += label_len; size += lo->file_path_length; if (lo->optional_data) size += (utf8_utf16_strlen((const char *)lo->optional_data) + 1) * sizeof(u16); p = malloc(size); if (!p) return 0; /* copy data */ *data = p; memcpy(p, &lo->attributes, sizeof(lo->attributes)); p += sizeof(lo->attributes); memcpy(p, &lo->file_path_length, sizeof(lo->file_path_length)); p += sizeof(lo->file_path_length); memcpy(p, lo->label, label_len); p += label_len; memcpy(p, lo->file_path, lo->file_path_length); p += lo->file_path_length; if (lo->optional_data) { utf8_utf16_strcpy((u16 **)&p, (const char *)lo->optional_data); p += sizeof(u16); /* size of trailing \0 */ } return size; } /** * get_var() - get UEFI variable * * It is the caller's duty to free the returned buffer. * * @name: name of variable * @vendor: vendor GUID of variable * @size: size of allocated buffer * Return: buffer with variable data or NULL */ static void *get_var(u16 *name, const efi_guid_t *vendor, efi_uintn_t *size) { efi_status_t ret; void *buf = NULL; *size = 0; ret = efi_get_variable_int(name, vendor, NULL, size, buf, NULL); if (ret == EFI_BUFFER_TOO_SMALL) { buf = malloc(*size); ret = efi_get_variable_int(name, vendor, NULL, size, buf, NULL); } if (ret != EFI_SUCCESS) { free(buf); *size = 0; return NULL; } return buf; } /** * try_load_entry() - try to load image for boot option * * Attempt to load load-option number 'n', returning device_path and file_path * if successful. This checks that the EFI_LOAD_OPTION is active (enabled) * and that the specified file to boot exists. * * @n: number of the boot option, e.g. 0x0a13 for Boot0A13 * @handle: on return handle for the newly installed image * @load_options: load options set on the loaded image protocol * Return: status code */ static efi_status_t try_load_entry(u16 n, efi_handle_t *handle, void **load_options) { struct efi_load_option lo; u16 varname[] = L"Boot0000"; u16 hexmap[] = L"0123456789ABCDEF"; void *load_option; efi_uintn_t size; efi_status_t ret; varname[4] = hexmap[(n & 0xf000) >> 12]; varname[5] = hexmap[(n & 0x0f00) >> 8]; varname[6] = hexmap[(n & 0x00f0) >> 4]; varname[7] = hexmap[(n & 0x000f) >> 0]; load_option = get_var(varname, &efi_global_variable_guid, &size); if (!load_option) return EFI_LOAD_ERROR; ret = efi_deserialize_load_option(&lo, load_option, &size); if (ret != EFI_SUCCESS) { log_warning("Invalid load option for %ls\n", varname); goto error; } if (lo.attributes & LOAD_OPTION_ACTIVE) { u32 attributes; log_debug("%s: trying to load \"%ls\" from %pD\n", __func__, lo.label, lo.file_path); ret = EFI_CALL(efi_load_image(true, efi_root, lo.file_path, NULL, 0, handle)); if (ret != EFI_SUCCESS) { log_warning("Loading %ls '%ls' failed\n", varname, lo.label); goto error; } attributes = EFI_VARIABLE_BOOTSERVICE_ACCESS | EFI_VARIABLE_RUNTIME_ACCESS; ret = efi_set_variable_int(L"BootCurrent", &efi_global_variable_guid, attributes, sizeof(n), &n, false); if (ret != EFI_SUCCESS) { if (EFI_CALL(efi_unload_image(*handle)) != EFI_SUCCESS) log_err("Unloading image failed\n"); goto error; } log_info("Booting: %ls\n", lo.label); } else { ret = EFI_LOAD_ERROR; } /* Set load options */ if (size) { *load_options = malloc(size); if (!*load_options) { ret = EFI_OUT_OF_RESOURCES; goto error; } memcpy(*load_options, lo.optional_data, size); ret = efi_set_load_options(*handle, size, *load_options); } else { load_options = NULL; } error: free(load_option); return ret; } /** * efi_bootmgr_load() - try to load from BootNext or BootOrder * * Attempt to load from BootNext or in the order specified by BootOrder * EFI variable, the available load-options, finding and returning * the first one that can be loaded successfully. * * @handle: on return handle for the newly installed image * @load_options: load options set on the loaded image protocol * Return: status code */ efi_status_t efi_bootmgr_load(efi_handle_t *handle, void **load_options) { u16 bootnext, *bootorder; efi_uintn_t size; int i, num; efi_status_t ret; bs = systab.boottime; rs = systab.runtime; /* BootNext */ size = sizeof(bootnext); ret = efi_get_variable_int(L"BootNext", &efi_global_variable_guid, NULL, &size, &bootnext, NULL); if (ret == EFI_SUCCESS || ret == EFI_BUFFER_TOO_SMALL) { /* BootNext does exist here */ if (ret == EFI_BUFFER_TOO_SMALL || size != sizeof(u16)) log_err("BootNext must be 16-bit integer\n"); /* delete BootNext */ ret = efi_set_variable_int(L"BootNext", &efi_global_variable_guid, 0, 0, NULL, false); /* load BootNext */ if (ret == EFI_SUCCESS) { if (size == sizeof(u16)) { ret = try_load_entry(bootnext, handle, load_options); if (ret == EFI_SUCCESS) return ret; log_warning( "Loading from BootNext failed, falling back to BootOrder\n"); } } else { log_err("Deleting BootNext failed\n"); } } /* BootOrder */ bootorder = get_var(L"BootOrder", &efi_global_variable_guid, &size); if (!bootorder) { log_info("BootOrder not defined\n"); ret = EFI_NOT_FOUND; goto error; } num = size / sizeof(uint16_t); for (i = 0; i < num; i++) { log_debug("%s trying to load Boot%04X\n", __func__, bootorder[i]); ret = try_load_entry(bootorder[i], handle, load_options); if (ret == EFI_SUCCESS) break; } free(bootorder); error: return ret; }