| // SPDX-License-Identifier: GPL-2.0 |
| /* |
| * Copyright (C) Microsoft Corporation |
| * |
| * Implements a firmware TPM as described here: |
| * https://www.microsoft.com/en-us/research/publication/ftpm-software-implementation-tpm-chip/ |
| * |
| * A reference implementation is available here: |
| * https://github.com/microsoft/ms-tpm-20-ref/tree/master/Samples/ARM32-FirmwareTPM/optee_ta/fTPM |
| */ |
| |
| #include <linux/acpi.h> |
| #include <linux/of.h> |
| #include <linux/of_platform.h> |
| #include <linux/platform_device.h> |
| #include <linux/tee_drv.h> |
| #include <linux/tpm.h> |
| #include <linux/uuid.h> |
| |
| #include "tpm.h" |
| #include "tpm_ftpm_tee.h" |
| |
| /* |
| * TA_FTPM_UUID: BC50D971-D4C9-42C4-82CB-343FB7F37896 |
| * |
| * Randomly generated, and must correspond to the GUID on the TA side. |
| * Defined here in the reference implementation: |
| * https://github.com/microsoft/ms-tpm-20-ref/blob/master/Samples/ARM32-FirmwareTPM/optee_ta/fTPM/include/fTPM.h#L42 |
| */ |
| static const uuid_t ftpm_ta_uuid = |
| UUID_INIT(0xBC50D971, 0xD4C9, 0x42C4, |
| 0x82, 0xCB, 0x34, 0x3F, 0xB7, 0xF3, 0x78, 0x96); |
| |
| /** |
| * ftpm_tee_tpm_op_recv() - retrieve fTPM response. |
| * @chip: the tpm_chip description as specified in driver/char/tpm/tpm.h. |
| * @buf: the buffer to store data. |
| * @count: the number of bytes to read. |
| * |
| * Return: |
| * In case of success the number of bytes received. |
| * On failure, -errno. |
| */ |
| static int ftpm_tee_tpm_op_recv(struct tpm_chip *chip, u8 *buf, size_t count) |
| { |
| struct ftpm_tee_private *pvt_data = dev_get_drvdata(chip->dev.parent); |
| size_t len; |
| |
| len = pvt_data->resp_len; |
| if (count < len) { |
| dev_err(&chip->dev, |
| "%s: Invalid size in recv: count=%zd, resp_len=%zd\n", |
| __func__, count, len); |
| return -EIO; |
| } |
| |
| memcpy(buf, pvt_data->resp_buf, len); |
| pvt_data->resp_len = 0; |
| |
| return len; |
| } |
| |
| /** |
| * ftpm_tee_tpm_op_send() - send TPM commands through the TEE shared memory. |
| * @chip: the tpm_chip description as specified in driver/char/tpm/tpm.h |
| * @buf: the buffer to send. |
| * @len: the number of bytes to send. |
| * |
| * Return: |
| * In case of success, returns 0. |
| * On failure, -errno |
| */ |
| static int ftpm_tee_tpm_op_send(struct tpm_chip *chip, u8 *buf, size_t len) |
| { |
| struct ftpm_tee_private *pvt_data = dev_get_drvdata(chip->dev.parent); |
| size_t resp_len; |
| int rc; |
| u8 *temp_buf; |
| struct tpm_header *resp_header; |
| struct tee_ioctl_invoke_arg transceive_args; |
| struct tee_param command_params[4]; |
| struct tee_shm *shm = pvt_data->shm; |
| |
| if (len > MAX_COMMAND_SIZE) { |
| dev_err(&chip->dev, |
| "%s: len=%zd exceeds MAX_COMMAND_SIZE supported by fTPM TA\n", |
| __func__, len); |
| return -EIO; |
| } |
| |
| memset(&transceive_args, 0, sizeof(transceive_args)); |
| memset(command_params, 0, sizeof(command_params)); |
| pvt_data->resp_len = 0; |
| |
| /* Invoke FTPM_OPTEE_TA_SUBMIT_COMMAND function of fTPM TA */ |
| transceive_args = (struct tee_ioctl_invoke_arg) { |
| .func = FTPM_OPTEE_TA_SUBMIT_COMMAND, |
| .session = pvt_data->session, |
| .num_params = 4, |
| }; |
| |
| /* Fill FTPM_OPTEE_TA_SUBMIT_COMMAND parameters */ |
| command_params[0] = (struct tee_param) { |
| .attr = TEE_IOCTL_PARAM_ATTR_TYPE_MEMREF_INPUT, |
| .u.memref = { |
| .shm = shm, |
| .size = len, |
| .shm_offs = 0, |
| }, |
| }; |
| |
| temp_buf = tee_shm_get_va(shm, 0); |
| if (IS_ERR(temp_buf)) { |
| dev_err(&chip->dev, "%s: tee_shm_get_va failed for transmit\n", |
| __func__); |
| return PTR_ERR(temp_buf); |
| } |
| memset(temp_buf, 0, (MAX_COMMAND_SIZE + MAX_RESPONSE_SIZE)); |
| memcpy(temp_buf, buf, len); |
| |
| command_params[1] = (struct tee_param) { |
| .attr = TEE_IOCTL_PARAM_ATTR_TYPE_MEMREF_INOUT, |
| .u.memref = { |
| .shm = shm, |
| .size = MAX_RESPONSE_SIZE, |
| .shm_offs = MAX_COMMAND_SIZE, |
| }, |
| }; |
| |
| rc = tee_client_invoke_func(pvt_data->ctx, &transceive_args, |
| command_params); |
| if ((rc < 0) || (transceive_args.ret != 0)) { |
| dev_err(&chip->dev, "%s: SUBMIT_COMMAND invoke error: 0x%x\n", |
| __func__, transceive_args.ret); |
| return (rc < 0) ? rc : transceive_args.ret; |
| } |
| |
| temp_buf = tee_shm_get_va(shm, command_params[1].u.memref.shm_offs); |
| if (IS_ERR(temp_buf)) { |
| dev_err(&chip->dev, "%s: tee_shm_get_va failed for receive\n", |
| __func__); |
| return PTR_ERR(temp_buf); |
| } |
| |
| resp_header = (struct tpm_header *)temp_buf; |
| resp_len = be32_to_cpu(resp_header->length); |
| |
| /* sanity check resp_len */ |
| if (resp_len < TPM_HEADER_SIZE) { |
| dev_err(&chip->dev, "%s: tpm response header too small\n", |
| __func__); |
| return -EIO; |
| } |
| if (resp_len > MAX_RESPONSE_SIZE) { |
| dev_err(&chip->dev, |
| "%s: resp_len=%zd exceeds MAX_RESPONSE_SIZE\n", |
| __func__, resp_len); |
| return -EIO; |
| } |
| |
| /* sanity checks look good, cache the response */ |
| memcpy(pvt_data->resp_buf, temp_buf, resp_len); |
| pvt_data->resp_len = resp_len; |
| |
| return 0; |
| } |
| |
| static void ftpm_tee_tpm_op_cancel(struct tpm_chip *chip) |
| { |
| /* not supported */ |
| } |
| |
| static u8 ftpm_tee_tpm_op_status(struct tpm_chip *chip) |
| { |
| return 0; |
| } |
| |
| static bool ftpm_tee_tpm_req_canceled(struct tpm_chip *chip, u8 status) |
| { |
| return false; |
| } |
| |
| static const struct tpm_class_ops ftpm_tee_tpm_ops = { |
| .flags = TPM_OPS_AUTO_STARTUP, |
| .recv = ftpm_tee_tpm_op_recv, |
| .send = ftpm_tee_tpm_op_send, |
| .cancel = ftpm_tee_tpm_op_cancel, |
| .status = ftpm_tee_tpm_op_status, |
| .req_complete_mask = 0, |
| .req_complete_val = 0, |
| .req_canceled = ftpm_tee_tpm_req_canceled, |
| }; |
| |
| /* |
| * Check whether this driver supports the fTPM TA in the TEE instance |
| * represented by the params (ver/data) to this function. |
| */ |
| static int ftpm_tee_match(struct tee_ioctl_version_data *ver, const void *data) |
| { |
| /* |
| * Currently this driver only support GP Complaint OPTEE based fTPM TA |
| */ |
| if ((ver->impl_id == TEE_IMPL_ID_OPTEE) && |
| (ver->gen_caps & TEE_GEN_CAP_GP)) |
| return 1; |
| else |
| return 0; |
| } |
| |
| /** |
| * ftpm_tee_probe() - initialize the fTPM |
| * @pdev: the platform_device description. |
| * |
| * Return: |
| * On success, 0. On failure, -errno. |
| */ |
| static int ftpm_tee_probe(struct device *dev) |
| { |
| int rc; |
| struct tpm_chip *chip; |
| struct ftpm_tee_private *pvt_data = NULL; |
| struct tee_ioctl_open_session_arg sess_arg; |
| |
| pvt_data = devm_kzalloc(dev, sizeof(struct ftpm_tee_private), |
| GFP_KERNEL); |
| if (!pvt_data) |
| return -ENOMEM; |
| |
| dev_set_drvdata(dev, pvt_data); |
| |
| /* Open context with TEE driver */ |
| pvt_data->ctx = tee_client_open_context(NULL, ftpm_tee_match, NULL, |
| NULL); |
| if (IS_ERR(pvt_data->ctx)) { |
| if (PTR_ERR(pvt_data->ctx) == -ENOENT) |
| return -EPROBE_DEFER; |
| dev_err(dev, "%s: tee_client_open_context failed\n", __func__); |
| return PTR_ERR(pvt_data->ctx); |
| } |
| |
| /* Open a session with fTPM TA */ |
| memset(&sess_arg, 0, sizeof(sess_arg)); |
| export_uuid(sess_arg.uuid, &ftpm_ta_uuid); |
| sess_arg.clnt_login = TEE_IOCTL_LOGIN_PUBLIC; |
| sess_arg.num_params = 0; |
| |
| rc = tee_client_open_session(pvt_data->ctx, &sess_arg, NULL); |
| if ((rc < 0) || (sess_arg.ret != 0)) { |
| dev_err(dev, "%s: tee_client_open_session failed, err=%x\n", |
| __func__, sess_arg.ret); |
| rc = -EINVAL; |
| goto out_tee_session; |
| } |
| pvt_data->session = sess_arg.session; |
| |
| /* Allocate dynamic shared memory with fTPM TA */ |
| pvt_data->shm = tee_shm_alloc_kernel_buf(pvt_data->ctx, |
| MAX_COMMAND_SIZE + |
| MAX_RESPONSE_SIZE); |
| if (IS_ERR(pvt_data->shm)) { |
| dev_err(dev, "%s: tee_shm_alloc_kernel_buf failed\n", __func__); |
| rc = -ENOMEM; |
| goto out_shm_alloc; |
| } |
| |
| /* Allocate new struct tpm_chip instance */ |
| chip = tpm_chip_alloc(dev, &ftpm_tee_tpm_ops); |
| if (IS_ERR(chip)) { |
| dev_err(dev, "%s: tpm_chip_alloc failed\n", __func__); |
| rc = PTR_ERR(chip); |
| goto out_chip_alloc; |
| } |
| |
| pvt_data->chip = chip; |
| pvt_data->chip->flags |= TPM_CHIP_FLAG_TPM2; |
| |
| /* Create a character device for the fTPM */ |
| rc = tpm_chip_register(pvt_data->chip); |
| if (rc) { |
| dev_err(dev, "%s: tpm_chip_register failed with rc=%d\n", |
| __func__, rc); |
| goto out_chip; |
| } |
| |
| return 0; |
| |
| out_chip: |
| put_device(&pvt_data->chip->dev); |
| out_chip_alloc: |
| tee_shm_free(pvt_data->shm); |
| out_shm_alloc: |
| tee_client_close_session(pvt_data->ctx, pvt_data->session); |
| out_tee_session: |
| tee_client_close_context(pvt_data->ctx); |
| |
| return rc; |
| } |
| |
| static int ftpm_plat_tee_probe(struct platform_device *pdev) |
| { |
| struct device *dev = &pdev->dev; |
| |
| return ftpm_tee_probe(dev); |
| } |
| |
| /** |
| * ftpm_tee_remove() - remove the TPM device |
| * @pdev: the platform_device description. |
| * |
| * Return: |
| * 0 always. |
| */ |
| static int ftpm_tee_remove(struct device *dev) |
| { |
| struct ftpm_tee_private *pvt_data = dev_get_drvdata(dev); |
| |
| /* Release the chip */ |
| tpm_chip_unregister(pvt_data->chip); |
| |
| /* frees chip */ |
| put_device(&pvt_data->chip->dev); |
| |
| /* Free the shared memory pool */ |
| tee_shm_free(pvt_data->shm); |
| |
| /* close the existing session with fTPM TA*/ |
| tee_client_close_session(pvt_data->ctx, pvt_data->session); |
| |
| /* close the context with TEE driver */ |
| tee_client_close_context(pvt_data->ctx); |
| |
| /* memory allocated with devm_kzalloc() is freed automatically */ |
| |
| return 0; |
| } |
| |
| static int ftpm_plat_tee_remove(struct platform_device *pdev) |
| { |
| struct device *dev = &pdev->dev; |
| |
| return ftpm_tee_remove(dev); |
| } |
| |
| /** |
| * ftpm_tee_shutdown() - shutdown the TPM device |
| * @pdev: the platform_device description. |
| */ |
| static void ftpm_plat_tee_shutdown(struct platform_device *pdev) |
| { |
| struct ftpm_tee_private *pvt_data = dev_get_drvdata(&pdev->dev); |
| |
| tee_shm_free(pvt_data->shm); |
| tee_client_close_session(pvt_data->ctx, pvt_data->session); |
| tee_client_close_context(pvt_data->ctx); |
| } |
| |
| static const struct of_device_id of_ftpm_tee_ids[] = { |
| { .compatible = "microsoft,ftpm" }, |
| { } |
| }; |
| MODULE_DEVICE_TABLE(of, of_ftpm_tee_ids); |
| |
| static struct platform_driver ftpm_tee_plat_driver = { |
| .driver = { |
| .name = "ftpm-tee", |
| .of_match_table = of_match_ptr(of_ftpm_tee_ids), |
| }, |
| .shutdown = ftpm_plat_tee_shutdown, |
| .probe = ftpm_plat_tee_probe, |
| .remove = ftpm_plat_tee_remove, |
| }; |
| |
| /* UUID of the fTPM TA */ |
| static const struct tee_client_device_id optee_ftpm_id_table[] = { |
| {UUID_INIT(0xbc50d971, 0xd4c9, 0x42c4, |
| 0x82, 0xcb, 0x34, 0x3f, 0xb7, 0xf3, 0x78, 0x96)}, |
| {} |
| }; |
| |
| MODULE_DEVICE_TABLE(tee, optee_ftpm_id_table); |
| |
| static struct tee_client_driver ftpm_tee_driver = { |
| .id_table = optee_ftpm_id_table, |
| .driver = { |
| .name = "optee-ftpm", |
| .bus = &tee_bus_type, |
| .probe = ftpm_tee_probe, |
| .remove = ftpm_tee_remove, |
| }, |
| }; |
| |
| static int __init ftpm_mod_init(void) |
| { |
| int rc; |
| |
| rc = platform_driver_register(&ftpm_tee_plat_driver); |
| if (rc) |
| return rc; |
| |
| return driver_register(&ftpm_tee_driver.driver); |
| } |
| |
| static void __exit ftpm_mod_exit(void) |
| { |
| platform_driver_unregister(&ftpm_tee_plat_driver); |
| driver_unregister(&ftpm_tee_driver.driver); |
| } |
| |
| module_init(ftpm_mod_init); |
| module_exit(ftpm_mod_exit); |
| |
| MODULE_AUTHOR("Thirupathaiah Annapureddy <thiruan@microsoft.com>"); |
| MODULE_DESCRIPTION("TPM Driver for fTPM TA in TEE"); |
| MODULE_LICENSE("GPL v2"); |