Add a driver for a firmware TPM running inside TEE.

Documentation of the firmware TPM: https://www.microsoft.com/en-us/research/publication/ftpm-software-implement...

Implementation of the firmware TPM: https://github.com/Microsoft/ms-tpm-20-ref/tree/master/Samples/ARM32-Firmwar...

Signed-off-by: Thirupathaiah Annapureddy thiruan@linux.microsoft.com --- drivers/tpm/Kconfig | 6 + drivers/tpm/Makefile | 1 + drivers/tpm/tpm2_ftpm_tee.c | 250 ++++++++++++++++++++++++++++++++++++ drivers/tpm/tpm2_ftpm_tee.h | 35 +++++ 4 files changed, 292 insertions(+) create mode 100644 drivers/tpm/tpm2_ftpm_tee.c create mode 100644 drivers/tpm/tpm2_ftpm_tee.h

diff --git a/drivers/tpm/Kconfig b/drivers/tpm/Kconfig index 94629dffd2..81bbffc50d 100644 --- a/drivers/tpm/Kconfig +++ b/drivers/tpm/Kconfig @@ -145,6 +145,12 @@ config TPM2_TIS_SPI to the device using the standard TPM Interface Specification (TIS) protocol.

+config TPM2_FTPM_TEE + bool "TEE based fTPM Interface" + depends on TEE && OPTEE && TPM_V2 + help + This driver supports firmware TPM running in TEE. + endif # TPM_V2

endmenu diff --git a/drivers/tpm/Makefile b/drivers/tpm/Makefile index 94c337b8ed..b1be3feac8 100644 --- a/drivers/tpm/Makefile +++ b/drivers/tpm/Makefile @@ -12,3 +12,4 @@ obj-$(CONFIG_TPM_ST33ZP24_SPI) += tpm_tis_st33zp24_spi.o

obj-$(CONFIG_TPM2_TIS_SANDBOX) += tpm2_tis_sandbox.o obj-$(CONFIG_TPM2_TIS_SPI) += tpm2_tis_spi.o +obj-$(CONFIG_TPM2_FTPM_TEE) += tpm2_ftpm_tee.o diff --git a/drivers/tpm/tpm2_ftpm_tee.c b/drivers/tpm/tpm2_ftpm_tee.c new file mode 100644 index 0000000000..4b79d4ada0 --- /dev/null +++ b/drivers/tpm/tpm2_ftpm_tee.c @@ -0,0 +1,250 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Copyright (C) Microsoft Corporation + * + * Authors: + * Thirupathaiah Annapureddy thiruan@microsoft.com + * + * Description: + * Device Driver for a firmware TPM as described here: + * https://www.microsoft.com/en-us/research/publication/ftpm-software-implement... + * + * A reference implementation is available here: + * https://github.com/microsoft/ms-tpm-20-ref/tree/master/Samples/ARM32-Firmwar... + */ + +#include <common.h> +#include <dm.h> +#include <tpm-v2.h> +#include <tee.h> + +#include "tpm_tis.h" +#include "tpm2_ftpm_tee.h" + +/** + * ftpm_tee_transceive() - send fTPM commands and retrieve fTPM response. + * @sendbuf - address of the data to send, byte by byte + * @send_size - length of the data to send + * @recvbuf - address where to read the response, byte by byte. + * @recv_len - pointer to the size of buffer + * + * Return: + * In case of success, returns 0. + * On failure, -errno + */ +static int ftpm_tee_transceive(struct udevice *dev, const u8 *sendbuf, + size_t send_size, u8 *recvbuf, + size_t *recv_len) +{ + struct ftpm_tee_private *context = dev_get_priv(dev); + int rc = 0; + size_t resp_len; + u8 *resp_buf; + struct tpm_output_header *resp_header; + struct tee_invoke_arg transceive_args; + struct tee_param command_params[4]; + struct tee_shm *shm; + + if (send_size > MAX_COMMAND_SIZE) { + debug("%s:send_size=%zd exceeds MAX_COMMAND_SIZE\n", + __func__, send_size); + return -EIO; + } + + shm = context->shm; + memset(&transceive_args, 0, sizeof(transceive_args)); + memset(command_params, 0, sizeof(command_params)); + + /* Invoke FTPM_OPTEE_TA_SUBMIT_COMMAND function of fTPM TA */ + transceive_args = (struct tee_invoke_arg) { + .func = FTPM_OPTEE_TA_SUBMIT_COMMAND, + .session = context->session, + }; + + /* Fill FTPM_OPTEE_TA_SUBMIT_COMMAND parameters */ + /* request */ + command_params[0] = (struct tee_param) { + .attr = TEE_PARAM_ATTR_TYPE_MEMREF_INPUT, + .u.memref = { + .shm = shm, + .size = send_size, + .shm_offs = 0, + }, + }; + memset(command_params[0].u.memref.shm->addr, 0, + (MAX_COMMAND_SIZE + MAX_RESPONSE_SIZE)); + memcpy(command_params[0].u.memref.shm->addr, sendbuf, send_size); + + /* response */ + command_params[1] = (struct tee_param) { + .attr = TEE_PARAM_ATTR_TYPE_MEMREF_INOUT, + .u.memref = { + .shm = shm, + .size = MAX_RESPONSE_SIZE, + .shm_offs = MAX_COMMAND_SIZE, + }, + }; + + rc = tee_invoke_func(context->tee_dev, &transceive_args, 4, + command_params); + if ((rc < 0) || (transceive_args.ret != 0)) { + debug("%s:SUBMIT_COMMAND invoke error: 0x%x\n", + __func__, transceive_args.ret); + return (rc < 0) ? rc : transceive_args.ret; + } + + resp_buf = command_params[1].u.memref.shm->addr + + command_params[1].u.memref.shm_offs; + resp_header = (struct tpm_output_header *)resp_buf; + resp_len = be32_to_cpu(resp_header->length); + + /* sanity check resp_len*/ + if (resp_len < TPM_HEADER_SIZE) { + debug("%s:tpm response header too small\n", __func__); + return -EIO; + } + if (resp_len > MAX_RESPONSE_SIZE) { + debug("%s:resp_len=%zd exceeds MAX_RESPONSE_SIZE\n", + __func__, resp_len); + return -EIO; + } + if (resp_len > *recv_len) { + debug("%s:response length is bigger than receive buffer\n", + __func__); + return -EIO; + } + + /* sanity checks look good, copy the response */ + memcpy(recvbuf, resp_buf, resp_len); + *recv_len = resp_len; + + return 0; +} + +static int ftpm_tee_open(struct udevice *dev) +{ + struct ftpm_tee_private *context = dev_get_priv(dev); + + if (context->is_open) + return -EBUSY; + + context->is_open = 1; + + return 0; +} + +static int ftpm_tee_close(struct udevice *dev) +{ + struct ftpm_tee_private *context = dev_get_priv(dev); + + if (context->is_open) + context->is_open = 0; + + return 0; +} + +static int ftpm_tee_desc(struct udevice *dev, char *buf, int size) +{ + if (size < 32) + return -ENOSPC; + + return snprintf(buf, size, "Microsoft OP-TEE fTPM"); +} + +static int ftpm_tee_match(struct tee_version_data *vers, const void *data) +{ + debug("%s:vers->gen_caps =0x%x\n", __func__, vers->gen_caps); + + /* + * Currently this driver only support GP Complaint OPTEE based fTPM TA + */ + return vers->gen_caps & TEE_GEN_CAP_GP; +} + +static int ftpm_tee_probe(struct udevice *dev) +{ + int rc; + struct tpm_chip_priv *priv = dev_get_uclass_priv(dev); + struct ftpm_tee_private *context = dev_get_priv(dev); + struct tee_open_session_arg sess_arg; + const struct tee_optee_ta_uuid uuid = TA_FTPM_UUID; + + memset(context, 0, sizeof(*context)); + + /* Use the TPM v2 stack */ + priv->version = TPM_V2; + priv->pcr_count = 24; + priv->pcr_select_min = 3; + + /* Find TEE device */ + context->tee_dev = tee_find_device(NULL, ftpm_tee_match, NULL, NULL); + if (!context->tee_dev) { + debug("%s:tee_find_device failed\n", __func__); + return -ENODEV; + } + + /* Open a session with the fTPM TA */ + memset(&sess_arg, 0, sizeof(sess_arg)); + tee_optee_ta_uuid_to_octets(sess_arg.uuid, &uuid); + + rc = tee_open_session(context->tee_dev, &sess_arg, 0, NULL); + if ((rc < 0) || (sess_arg.ret != 0)) { + debug("%s:tee_open_session failed, err=%x\n", + __func__, sess_arg.ret); + return -EIO; + } + context->session = sess_arg.session; + + /* Allocate dynamic shared memory with fTPM TA */ + rc = tee_shm_alloc(context->tee_dev, + MAX_COMMAND_SIZE + MAX_RESPONSE_SIZE, + 0, &context->shm); + if (rc) { + debug("%s:tee_shm_alloc failed with rc = %d\n", __func__, rc); + goto out_shm_alloc; + } + + return 0; + +out_shm_alloc: + tee_close_session(context->tee_dev, context->session); + + return rc; +} + +static int ftpm_tee_remove(struct udevice *dev) +{ + struct ftpm_tee_private *context = dev_get_priv(dev); + int rc; + + /* tee_pre_remove frees any leftover TEE shared memory */ + + /* close the existing session with fTPM TA*/ + rc = tee_close_session(context->tee_dev, context->session); + debug("%s: tee_close_session - rc =%d\n", __func__, rc); + + return 0; +} + +static const struct tpm_ops ftpm_tee_ops = { + .open = ftpm_tee_open, + .close = ftpm_tee_close, + .get_desc = ftpm_tee_desc, + .xfer = ftpm_tee_transceive, +}; + +static const struct udevice_id ftpm_tee_ids[] = { + { .compatible = "microsoft,ftpm" }, + { } +}; + +U_BOOT_DRIVER(ftpm_tee) = { + .name = "ftpm_tee", + .id = UCLASS_TPM, + .of_match = ftpm_tee_ids, + .ops = &ftpm_tee_ops, + .probe = ftpm_tee_probe, + .remove = ftpm_tee_remove, + .flags = DM_FLAG_OS_PREPARE, + .priv_auto_alloc_size = sizeof(struct ftpm_tee_private), +}; diff --git a/drivers/tpm/tpm2_ftpm_tee.h b/drivers/tpm/tpm2_ftpm_tee.h new file mode 100644 index 0000000000..44f9598c28 --- /dev/null +++ b/drivers/tpm/tpm2_ftpm_tee.h @@ -0,0 +1,35 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +/* + * Copyright (C) Microsoft Corporation + */ + +#ifndef __TPM2_FTPM_TEE_H__ +#define __TPM2_FTPM_TEE_H__ + +/* This UUID is generated with uuidgen */ +#define TA_FTPM_UUID { 0xBC50D971, 0xD4C9, 0x42C4, \ + {0x82, 0xCB, 0x34, 0x3F, 0xB7, 0xF3, 0x78, 0x96} } + +/* The TAFs ID implemented in this TA */ +#define FTPM_OPTEE_TA_SUBMIT_COMMAND (0) +#define FTPM_OPTEE_TA_EMULATE_PPI (1) + +/* max. buffer size supported by fTPM */ +#define MAX_COMMAND_SIZE 4096 +#define MAX_RESPONSE_SIZE 4096 + +/** + * struct ftpm_tee_private - fTPM's private context + * @tee_dev: struct udevice for TEE. + * @session: fTPM TA session identifier. + * @is_open: Indicates whether the driver is already opened by client or not. + * @shm: Memory pool shared with fTPM TA in TEE. + */ +struct ftpm_tee_private { + struct udevice *tee_dev; + u32 session; + int is_open; + struct tee_shm *shm; +}; + +#endif /* __TPM2_FTPM_TEE_H__ */