// SPDX-License-Identifier: GPL-2.0+ /* * Defines APIs that allow an OS to interact with UEFI firmware to query * information about the device. * https://trustedcomputinggroup.org/resource/tcg-efi-protocol-specification/ * * Copyright (c) 2020, Linaro Limited */ #define LOG_CATEGORY LOGC_EFI #include #include #include #include #include #include #include #include DECLARE_GLOBAL_DATA_PTR; /* * When requesting TPM2_CAP_TPM_PROPERTIES the value is on a standard offset. * Since the current tpm2_get_capability() response buffers starts at * 'union tpmu_capabilities data' of 'struct tpms_capability_data', calculate * the response size and offset once for all consumers */ #define TPM2_RESPONSE_BUFFER_SIZE (sizeof(struct tpms_capability_data) - \ offsetof(struct tpms_capability_data, data)) #define properties_offset (offsetof(struct tpml_tagged_tpm_property, tpm_property) + \ offsetof(struct tpms_tagged_property, value)) const efi_guid_t efi_guid_tcg2_protocol = EFI_TCG2_PROTOCOL_GUID; /** * platform_get_tpm_device() - retrieve TPM device * * This function retrieves the udevice implementing a TPM * * This function may be overridden if special initialization is needed. * * @dev: udevice * Return: status code */ __weak efi_status_t platform_get_tpm2_device(struct udevice **dev) { for_each_tpm_device((*dev)) { if (tpm_get_version(*dev) == TPM_V2) return EFI_SUCCESS; } return EFI_NOT_FOUND; } /** * tpm2_get_max_command_size() - get the supported max command size * * @dev: TPM device * @max_command_size: output buffer for the size * * Return: 0 on success, -1 on error */ static int tpm2_get_max_command_size(struct udevice *dev, u16 *max_command_size) { u8 response[TPM2_RESPONSE_BUFFER_SIZE]; u32 ret; memset(response, 0, sizeof(response)); ret = tpm2_get_capability(dev, TPM2_CAP_TPM_PROPERTIES, TPM2_PT_MAX_COMMAND_SIZE, response, 1); if (ret) return -1; *max_command_size = (uint16_t)get_unaligned_be32(response + properties_offset); return 0; } /** * tpm2_get_max_response_size() - get the supported max response size * * @dev: TPM device * @max_response_size: output buffer for the size * * Return: 0 on success, -1 on error */ static int tpm2_get_max_response_size(struct udevice *dev, u16 *max_response_size) { u8 response[TPM2_RESPONSE_BUFFER_SIZE]; u32 ret; memset(response, 0, sizeof(response)); ret = tpm2_get_capability(dev, TPM2_CAP_TPM_PROPERTIES, TPM2_PT_MAX_RESPONSE_SIZE, response, 1); if (ret) return -1; *max_response_size = (uint16_t)get_unaligned_be32(response + properties_offset); return 0; } /** * tpm2_get_manufacturer_id() - get the manufacturer ID * * @dev: TPM device * @manufacturer_id: output buffer for the id * * Return: 0 on success, -1 on error */ static int tpm2_get_manufacturer_id(struct udevice *dev, u32 *manufacturer_id) { u8 response[TPM2_RESPONSE_BUFFER_SIZE]; u32 ret; memset(response, 0, sizeof(response)); ret = tpm2_get_capability(dev, TPM2_CAP_TPM_PROPERTIES, TPM2_PT_MANUFACTURER, response, 1); if (ret) return -1; *manufacturer_id = get_unaligned_be32(response + properties_offset); return 0; } /** * tpm2_get_num_pcr() - get the number of PCRs * * @dev: TPM device * @manufacturer_id: output buffer for the number * * Return: 0 on success, -1 on error */ static int tpm2_get_num_pcr(struct udevice *dev, u32 *num_pcr) { u8 response[TPM2_RESPONSE_BUFFER_SIZE]; u32 ret; memset(response, 0, sizeof(response)); ret = tpm2_get_capability(dev, TPM2_CAP_TPM_PROPERTIES, TPM2_PT_PCR_COUNT, response, 1); if (ret) return -1; *num_pcr = get_unaligned_be32(response + properties_offset); if (*num_pcr > TPM2_MAX_PCRS) return -1; return 0; } /** * is_active_pcr() - Check if a supported algorithm is active * * @dev: TPM device * @selection: struct of PCR information * * Return: true if PCR is active */ bool is_active_pcr(struct tpms_pcr_selection *selection) { int i; /* * check the pcr_select. If at least one of the PCRs supports the * algorithm add it on the active ones */ for (i = 0; i < selection->size_of_select; i++) { if (selection->pcr_select[i]) return true; } return false; } /** * tpm2_get_pcr_info() - get the supported, active PCRs and number of banks * * @dev: TPM device * @supported_pcr: bitmask with the algorithms supported * @active_pcr: bitmask with the active algorithms * @pcr_banks: number of PCR banks * * Return: 0 on success, -1 on error */ static int tpm2_get_pcr_info(struct udevice *dev, u32 *supported_pcr, u32 *active_pcr, u32 *pcr_banks) { u8 response[TPM2_RESPONSE_BUFFER_SIZE]; struct tpml_pcr_selection pcrs; u32 ret, num_pcr; int i, tpm_ret; memset(response, 0, sizeof(response)); ret = tpm2_get_capability(dev, TPM2_CAP_PCRS, 0, response, 1); if (ret) goto out; pcrs.count = get_unaligned_be32(response); /* * We only support 5 algorithms for now so check against that * instead of TPM2_NUM_PCR_BANKS */ if (pcrs.count > MAX_HASH_COUNT || pcrs.count < 1) goto out; tpm_ret = tpm2_get_num_pcr(dev, &num_pcr); if (tpm_ret) goto out; for (i = 0; i < pcrs.count; i++) { /* * Definition of TPMS_PCR_SELECTION Structure * hash: u16 * size_of_select: u8 * pcr_select: u8 array * * The offsets depend on the number of the device PCRs * so we have to calculate them based on that */ u32 hash_offset = offsetof(struct tpml_pcr_selection, selection) + i * offsetof(struct tpms_pcr_selection, pcr_select) + i * ((num_pcr + 7) / 8); u32 size_select_offset = hash_offset + offsetof(struct tpms_pcr_selection, size_of_select); u32 pcr_select_offset = hash_offset + offsetof(struct tpms_pcr_selection, pcr_select); pcrs.selection[i].hash = get_unaligned_be16(response + hash_offset); pcrs.selection[i].size_of_select = __get_unaligned_be(response + size_select_offset); if (pcrs.selection[i].size_of_select > TPM2_PCR_SELECT_MAX) goto out; /* copy the array of pcr_select */ memcpy(pcrs.selection[i].pcr_select, response + pcr_select_offset, pcrs.selection[i].size_of_select); } for (i = 0; i < pcrs.count; i++) { switch (pcrs.selection[i].hash) { case TPM2_ALG_SHA1: *supported_pcr |= EFI_TCG2_BOOT_HASH_ALG_SHA1; if (is_active_pcr(&pcrs.selection[i])) *active_pcr |= EFI_TCG2_BOOT_HASH_ALG_SHA1; break; case TPM2_ALG_SHA256: *supported_pcr |= EFI_TCG2_BOOT_HASH_ALG_SHA256; if (is_active_pcr(&pcrs.selection[i])) *active_pcr |= EFI_TCG2_BOOT_HASH_ALG_SHA256; break; case TPM2_ALG_SHA384: *supported_pcr |= EFI_TCG2_BOOT_HASH_ALG_SHA384; if (is_active_pcr(&pcrs.selection[i])) *active_pcr |= EFI_TCG2_BOOT_HASH_ALG_SHA384; break; case TPM2_ALG_SHA512: *supported_pcr |= EFI_TCG2_BOOT_HASH_ALG_SHA512; if (is_active_pcr(&pcrs.selection[i])) *active_pcr |= EFI_TCG2_BOOT_HASH_ALG_SHA512; break; case TPM2_ALG_SM3_256: *supported_pcr |= EFI_TCG2_BOOT_HASH_ALG_SM3_256; if (is_active_pcr(&pcrs.selection[i])) *active_pcr |= EFI_TCG2_BOOT_HASH_ALG_SM3_256; break; default: EFI_PRINT("Unknown algorithm %x\n", pcrs.selection[i].hash); break; } } *pcr_banks = pcrs.count; return 0; out: return -1; } /** * get_capability() - protocol capability information and state information * * @this: TCG2 protocol instance * @capability: caller allocated memory with size field to the size of * the structure allocated * Return: status code */ static efi_status_t EFIAPI get_capability(struct efi_tcg2_protocol *this, struct efi_tcg2_boot_service_capability *capability) { struct udevice *dev; efi_status_t efi_ret; int ret; EFI_ENTRY("%p, %p", this, capability); if (!this || !capability) { efi_ret = EFI_INVALID_PARAMETER; goto out; } if (capability->size < boot_service_capability_min) { capability->size = boot_service_capability_min; efi_ret = EFI_BUFFER_TOO_SMALL; goto out; } if (capability->size < sizeof(*capability)) { capability->size = sizeof(*capability); efi_ret = EFI_BUFFER_TOO_SMALL; goto out; } capability->structure_version.major = 1; capability->structure_version.minor = 1; capability->protocol_version.major = 1; capability->protocol_version.minor = 1; efi_ret = platform_get_tpm2_device(&dev); if (efi_ret != EFI_SUCCESS) { capability->supported_event_logs = 0; capability->hash_algorithm_bitmap = 0; capability->tpm_present_flag = false; capability->max_command_size = 0; capability->max_response_size = 0; capability->manufacturer_id = 0; capability->number_of_pcr_banks = 0; capability->active_pcr_banks = 0; efi_ret = EFI_SUCCESS; goto out; } /* We only allow a TPMv2 device to register the EFI protocol */ capability->supported_event_logs = TCG2_EVENT_LOG_FORMAT_TCG_2; capability->tpm_present_flag = true; /* Supported and active PCRs */ capability->hash_algorithm_bitmap = 0; capability->active_pcr_banks = 0; ret = tpm2_get_pcr_info(dev, &capability->hash_algorithm_bitmap, &capability->active_pcr_banks, &capability->number_of_pcr_banks); if (ret) { efi_ret = EFI_DEVICE_ERROR; goto out; } /* Max command size */ ret = tpm2_get_max_command_size(dev, &capability->max_command_size); if (ret) { efi_ret = EFI_DEVICE_ERROR; goto out; } /* Max response size */ ret = tpm2_get_max_response_size(dev, &capability->max_response_size); if (ret) { efi_ret = EFI_DEVICE_ERROR; goto out; } /* Manufacturer ID */ ret = tpm2_get_manufacturer_id(dev, &capability->manufacturer_id); if (ret) { efi_ret = EFI_DEVICE_ERROR; goto out; } return EFI_EXIT(EFI_SUCCESS); out: return EFI_EXIT(efi_ret); } /** * get_eventlog() - retrieve the the address of an event log and its last entry * * @this: TCG2 protocol instance * @log_format: type of event log format * @event_log_location: pointer to the memory address of the event log * @event_log_last_entry: pointer to the address of the start of the last * entry in the event log in memory, if log contains * more than 1 entry * @event_log_truncated: set to true, if the Event Log is missing at i * least one entry * * Return: status code */ static efi_status_t EFIAPI get_eventlog(struct efi_tcg2_protocol *this, efi_tcg_event_log_format log_format, u64 *event_log_location, u64 *event_log_last_entry, bool *event_log_truncated) { return EFI_UNSUPPORTED; } /** * hash_log_extend_event()- extend and optionally log events * * @this: TCG2 protocol instance * @flags: bitmap providing additional information on the * operation * @data_to_hash: physical address of the start of the data buffer * to be hashed * @data_to_hash_len: the length in bytes of the buffer referenced by * data_to_hash * @efi_tcg_event: pointer to data buffer containing information * about the event * * Return: status code */ static efi_status_t EFIAPI hash_log_extend_event(struct efi_tcg2_protocol *this, u64 flags, u64 data_to_hash, u64 data_to_hash_len, struct efi_tcg2_event *efi_tcg_event) { return EFI_UNSUPPORTED; } /** * submit_command() - Send command to the TPM * * @this: TCG2 protocol instance * @input_param_block_size: size of the TPM input parameter block * @input_param_block: pointer to the TPM input parameter block * @output_param_block_size: size of the TPM output parameter block * @output_param_block: pointer to the TPM output parameter block * * Return: status code */ efi_status_t EFIAPI submit_command(struct efi_tcg2_protocol *this, u32 input_param_block_size, u8 *input_param_block, u32 output_param_block_size, u8 *output_param_block) { return EFI_UNSUPPORTED; } /** * get_active_pcr_banks() - returns the currently active PCR banks * * @this: TCG2 protocol instance * @active_pcr_banks: pointer for receiving the bitmap of currently * active PCR banks * * Return: status code */ efi_status_t EFIAPI get_active_pcr_banks(struct efi_tcg2_protocol *this, u32 *active_pcr_banks) { return EFI_UNSUPPORTED; } /** * set_active_pcr_banks() - sets the currently active PCR banks * * @this: TCG2 protocol instance * @active_pcr_banks: bitmap of the requested active PCR banks * * Return: status code */ efi_status_t EFIAPI set_active_pcr_banks(struct efi_tcg2_protocol *this, u32 active_pcr_banks) { return EFI_UNSUPPORTED; } /** * get_result_of_set_active_pcr_banks() - retrieves the result of a previous * set_active_pcr_banks() * * @this: TCG2 protocol instance * @operation_present: non-zero value to indicate a * set_active_pcr_banks operation was * invoked during last boot * @response: result value could be returned * * Return: status code */ efi_status_t EFIAPI get_result_of_set_active_pcr_banks(struct efi_tcg2_protocol *this, u32 *operation_present, u32 *response) { return EFI_UNSUPPORTED; } static const struct efi_tcg2_protocol efi_tcg2_protocol = { .get_capability = get_capability, .get_eventlog = get_eventlog, .hash_log_extend_event = hash_log_extend_event, .submit_command = submit_command, .get_active_pcr_banks = get_active_pcr_banks, .set_active_pcr_banks = set_active_pcr_banks, .get_result_of_set_active_pcr_banks = get_result_of_set_active_pcr_banks, }; /** * efi_tcg2_register() - register EFI_TCG2_PROTOCOL * * If a TPM2 device is available, the TPM TCG2 Protocol is registered * * Return: An error status is only returned if adding the protocol fails. */ efi_status_t efi_tcg2_register(void) { efi_status_t ret; struct udevice *dev; enum tpm_version tpm_ver; ret = platform_get_tpm2_device(&dev); if (ret != EFI_SUCCESS) return EFI_SUCCESS; tpm_ver = tpm_get_version(dev); if (tpm_ver != TPM_V2) { log_warning("Only TPMv2 supported for EFI_TCG2_PROTOCOL\n"); return EFI_SUCCESS; } ret = efi_add_protocol(efi_root, &efi_guid_tcg2_protocol, (void *)&efi_tcg2_protocol); if (ret != EFI_SUCCESS) log_err("Cannot install EFI_TCG2_PROTOCOL\n"); return ret; }