tpm/tpm_ftpm_tee: A driver for firmware TPM running inside TEE
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-implementation-tpm-chip/ . Implementation of the firmware TPM: https://github.com/Microsoft/ms-tpm-20-ref/tree/master/Samples/ARM32-FirmwareTPM Tested-by: Ilias Apalodimas <ilias.apalodimas@linaro.org> Tested-by: Thirupathaiah Annapureddy <thiruan@microsoft.com> Signed-off-by: Thirupathaiah Annapureddy <thiruan@microsoft.com> Co-authored-by: Sasha Levin <sashal@kernel.org> Signed-off-by: Sasha Levin <sashal@kernel.org> Reviewed-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com> Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
This commit is contained in:
parent
28eba2fddd
commit
09e574831b
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@ -575,6 +575,8 @@ patternProperties:
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description: Micro Crystal AG
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"^micron,.*":
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description: Micron Technology Inc.
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"^microsoft,.*":
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description: Microsoft Corporation
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"^mikroe,.*":
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description: MikroElektronika d.o.o.
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"^miniand,.*":
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@ -164,6 +164,11 @@ config TCG_VTPM_PROXY
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/dev/vtpmX and a server-side file descriptor on which the vTPM
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can receive commands.
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config TCG_FTPM_TEE
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tristate "TEE based fTPM Interface"
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depends on TEE && OPTEE
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help
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This driver proxies for firmware TPM running in TEE.
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source "drivers/char/tpm/st33zp24/Kconfig"
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endif # TCG_TPM
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@ -33,3 +33,4 @@ obj-$(CONFIG_TCG_TIS_ST33ZP24) += st33zp24/
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obj-$(CONFIG_TCG_XEN) += xen-tpmfront.o
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obj-$(CONFIG_TCG_CRB) += tpm_crb.o
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obj-$(CONFIG_TCG_VTPM_PROXY) += tpm_vtpm_proxy.o
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obj-$(CONFIG_TCG_FTPM_TEE) += tpm_ftpm_tee.o
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350
drivers/char/tpm/tpm_ftpm_tee.c
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350
drivers/char/tpm/tpm_ftpm_tee.c
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@ -0,0 +1,350 @@
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// SPDX-License-Identifier: GPL-2.0
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/*
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* Copyright (C) Microsoft Corporation
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*
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* Implements a firmware TPM as described here:
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* https://www.microsoft.com/en-us/research/publication/ftpm-software-implementation-tpm-chip/
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*
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* A reference implementation is available here:
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* https://github.com/microsoft/ms-tpm-20-ref/tree/master/Samples/ARM32-FirmwareTPM/optee_ta/fTPM
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*/
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#include <linux/acpi.h>
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#include <linux/of.h>
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#include <linux/of_platform.h>
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#include <linux/platform_device.h>
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#include <linux/tee_drv.h>
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#include <linux/tpm.h>
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#include <linux/uuid.h>
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#include "tpm.h"
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#include "tpm_ftpm_tee.h"
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/*
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* TA_FTPM_UUID: BC50D971-D4C9-42C4-82CB-343FB7F37896
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*
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* Randomly generated, and must correspond to the GUID on the TA side.
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* Defined here in the reference implementation:
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* https://github.com/microsoft/ms-tpm-20-ref/blob/master/Samples/ARM32-FirmwareTPM/optee_ta/fTPM/include/fTPM.h#L42
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*/
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static const uuid_t ftpm_ta_uuid =
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UUID_INIT(0xBC50D971, 0xD4C9, 0x42C4,
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0x82, 0xCB, 0x34, 0x3F, 0xB7, 0xF3, 0x78, 0x96);
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/**
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* ftpm_tee_tpm_op_recv - retrieve fTPM response.
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* @chip: the tpm_chip description as specified in driver/char/tpm/tpm.h.
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* @buf: the buffer to store data.
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* @count: the number of bytes to read.
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*
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* Return:
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* In case of success the number of bytes received.
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* On failure, -errno.
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*/
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static int ftpm_tee_tpm_op_recv(struct tpm_chip *chip, u8 *buf, size_t count)
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{
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struct ftpm_tee_private *pvt_data = dev_get_drvdata(chip->dev.parent);
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size_t len;
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len = pvt_data->resp_len;
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if (count < len) {
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dev_err(&chip->dev,
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"%s: Invalid size in recv: count=%zd, resp_len=%zd\n",
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__func__, count, len);
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return -EIO;
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}
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memcpy(buf, pvt_data->resp_buf, len);
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pvt_data->resp_len = 0;
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return len;
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}
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/**
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* ftpm_tee_tpm_op_send - send TPM commands through the TEE shared memory.
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* @chip: the tpm_chip description as specified in driver/char/tpm/tpm.h
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* @buf: the buffer to send.
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* @len: the number of bytes to send.
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*
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* Return:
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* In case of success, returns 0.
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* On failure, -errno
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*/
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static int ftpm_tee_tpm_op_send(struct tpm_chip *chip, u8 *buf, size_t len)
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{
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struct ftpm_tee_private *pvt_data = dev_get_drvdata(chip->dev.parent);
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size_t resp_len;
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int rc;
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u8 *temp_buf;
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struct tpm_header *resp_header;
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struct tee_ioctl_invoke_arg transceive_args;
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struct tee_param command_params[4];
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struct tee_shm *shm = pvt_data->shm;
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if (len > MAX_COMMAND_SIZE) {
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dev_err(&chip->dev,
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"%s: len=%zd exceeds MAX_COMMAND_SIZE supported by fTPM TA\n",
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__func__, len);
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return -EIO;
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}
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memset(&transceive_args, 0, sizeof(transceive_args));
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memset(command_params, 0, sizeof(command_params));
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pvt_data->resp_len = 0;
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/* Invoke FTPM_OPTEE_TA_SUBMIT_COMMAND function of fTPM TA */
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transceive_args = (struct tee_ioctl_invoke_arg) {
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.func = FTPM_OPTEE_TA_SUBMIT_COMMAND,
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.session = pvt_data->session,
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.num_params = 4,
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};
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/* Fill FTPM_OPTEE_TA_SUBMIT_COMMAND parameters */
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command_params[0] = (struct tee_param) {
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.attr = TEE_IOCTL_PARAM_ATTR_TYPE_MEMREF_INPUT,
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.u.memref = {
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.shm = shm,
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.size = len,
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.shm_offs = 0,
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},
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};
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temp_buf = tee_shm_get_va(shm, 0);
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if (IS_ERR(temp_buf)) {
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dev_err(&chip->dev, "%s: tee_shm_get_va failed for transmit\n",
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__func__);
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return PTR_ERR(temp_buf);
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}
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memset(temp_buf, 0, (MAX_COMMAND_SIZE + MAX_RESPONSE_SIZE));
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memcpy(temp_buf, buf, len);
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command_params[1] = (struct tee_param) {
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.attr = TEE_IOCTL_PARAM_ATTR_TYPE_MEMREF_INOUT,
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.u.memref = {
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.shm = shm,
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.size = MAX_RESPONSE_SIZE,
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.shm_offs = MAX_COMMAND_SIZE,
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},
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};
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rc = tee_client_invoke_func(pvt_data->ctx, &transceive_args,
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command_params);
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if ((rc < 0) || (transceive_args.ret != 0)) {
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dev_err(&chip->dev, "%s: SUBMIT_COMMAND invoke error: 0x%x\n",
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__func__, transceive_args.ret);
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return (rc < 0) ? rc : transceive_args.ret;
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}
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temp_buf = tee_shm_get_va(shm, command_params[1].u.memref.shm_offs);
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if (IS_ERR(temp_buf)) {
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dev_err(&chip->dev, "%s: tee_shm_get_va failed for receive\n",
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__func__);
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return PTR_ERR(temp_buf);
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}
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resp_header = (struct tpm_header *)temp_buf;
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resp_len = be32_to_cpu(resp_header->length);
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/* sanity check resp_len */
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if (resp_len < TPM_HEADER_SIZE) {
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dev_err(&chip->dev, "%s: tpm response header too small\n",
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__func__);
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return -EIO;
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}
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if (resp_len > MAX_RESPONSE_SIZE) {
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dev_err(&chip->dev,
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"%s: resp_len=%zd exceeds MAX_RESPONSE_SIZE\n",
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__func__, resp_len);
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return -EIO;
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}
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/* sanity checks look good, cache the response */
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memcpy(pvt_data->resp_buf, temp_buf, resp_len);
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pvt_data->resp_len = resp_len;
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return 0;
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}
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static void ftpm_tee_tpm_op_cancel(struct tpm_chip *chip)
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{
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/* not supported */
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}
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static u8 ftpm_tee_tpm_op_status(struct tpm_chip *chip)
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{
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return 0;
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}
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static bool ftpm_tee_tpm_req_canceled(struct tpm_chip *chip, u8 status)
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{
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return 0;
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}
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static const struct tpm_class_ops ftpm_tee_tpm_ops = {
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.flags = TPM_OPS_AUTO_STARTUP,
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.recv = ftpm_tee_tpm_op_recv,
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.send = ftpm_tee_tpm_op_send,
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.cancel = ftpm_tee_tpm_op_cancel,
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.status = ftpm_tee_tpm_op_status,
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.req_complete_mask = 0,
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.req_complete_val = 0,
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.req_canceled = ftpm_tee_tpm_req_canceled,
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};
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/*
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* Check whether this driver supports the fTPM TA in the TEE instance
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* represented by the params (ver/data) to this function.
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*/
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static int ftpm_tee_match(struct tee_ioctl_version_data *ver, const void *data)
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{
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/*
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* Currently this driver only support GP Complaint OPTEE based fTPM TA
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*/
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if ((ver->impl_id == TEE_IMPL_ID_OPTEE) &&
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(ver->gen_caps & TEE_GEN_CAP_GP))
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return 1;
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else
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return 0;
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}
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/**
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* ftpm_tee_probe - initialize the fTPM
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* @pdev: the platform_device description.
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*
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* Return:
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* On success, 0. On failure, -errno.
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*/
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static int ftpm_tee_probe(struct platform_device *pdev)
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{
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int rc;
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struct tpm_chip *chip;
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struct device *dev = &pdev->dev;
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struct ftpm_tee_private *pvt_data = NULL;
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struct tee_ioctl_open_session_arg sess_arg;
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pvt_data = devm_kzalloc(dev, sizeof(struct ftpm_tee_private),
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GFP_KERNEL);
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if (!pvt_data)
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return -ENOMEM;
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dev_set_drvdata(dev, pvt_data);
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/* Open context with TEE driver */
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pvt_data->ctx = tee_client_open_context(NULL, ftpm_tee_match, NULL,
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NULL);
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if (IS_ERR(pvt_data->ctx)) {
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if (PTR_ERR(pvt_data->ctx) == -ENOENT)
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return -EPROBE_DEFER;
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dev_err(dev, "%s: tee_client_open_context failed\n", __func__);
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return PTR_ERR(pvt_data->ctx);
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}
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/* Open a session with fTPM TA */
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memset(&sess_arg, 0, sizeof(sess_arg));
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memcpy(sess_arg.uuid, ftpm_ta_uuid.b, TEE_IOCTL_UUID_LEN);
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sess_arg.clnt_login = TEE_IOCTL_LOGIN_PUBLIC;
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sess_arg.num_params = 0;
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rc = tee_client_open_session(pvt_data->ctx, &sess_arg, NULL);
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if ((rc < 0) || (sess_arg.ret != 0)) {
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dev_err(dev, "%s: tee_client_open_session failed, err=%x\n",
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__func__, sess_arg.ret);
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rc = -EINVAL;
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goto out_tee_session;
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}
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pvt_data->session = sess_arg.session;
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/* Allocate dynamic shared memory with fTPM TA */
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pvt_data->shm = tee_shm_alloc(pvt_data->ctx,
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MAX_COMMAND_SIZE + MAX_RESPONSE_SIZE,
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TEE_SHM_MAPPED | TEE_SHM_DMA_BUF);
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if (IS_ERR(pvt_data->shm)) {
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dev_err(dev, "%s: tee_shm_alloc failed\n", __func__);
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rc = -ENOMEM;
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goto out_shm_alloc;
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}
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/* Allocate new struct tpm_chip instance */
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chip = tpm_chip_alloc(dev, &ftpm_tee_tpm_ops);
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if (IS_ERR(chip)) {
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dev_err(dev, "%s: tpm_chip_alloc failed\n", __func__);
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rc = PTR_ERR(chip);
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goto out_chip_alloc;
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}
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pvt_data->chip = chip;
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pvt_data->chip->flags |= TPM_CHIP_FLAG_TPM2;
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/* Create a character device for the fTPM */
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rc = tpm_chip_register(pvt_data->chip);
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if (rc) {
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dev_err(dev, "%s: tpm_chip_register failed with rc=%d\n",
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__func__, rc);
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goto out_chip;
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}
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return 0;
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out_chip:
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put_device(&pvt_data->chip->dev);
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out_chip_alloc:
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tee_shm_free(pvt_data->shm);
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out_shm_alloc:
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tee_client_close_session(pvt_data->ctx, pvt_data->session);
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out_tee_session:
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tee_client_close_context(pvt_data->ctx);
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return rc;
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}
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/**
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* ftpm_tee_remove - remove the TPM device
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* @pdev: the platform_device description.
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*
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* Return:
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* 0 always.
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*/
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static int ftpm_tee_remove(struct platform_device *pdev)
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{
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struct ftpm_tee_private *pvt_data = dev_get_drvdata(&pdev->dev);
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/* Release the chip */
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tpm_chip_unregister(pvt_data->chip);
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/* frees chip */
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put_device(&pvt_data->chip->dev);
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/* Free the shared memory pool */
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tee_shm_free(pvt_data->shm);
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/* close the existing session with fTPM TA*/
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tee_client_close_session(pvt_data->ctx, pvt_data->session);
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/* close the context with TEE driver */
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tee_client_close_context(pvt_data->ctx);
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/* memory allocated with devm_kzalloc() is freed automatically */
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return 0;
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}
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static const struct of_device_id of_ftpm_tee_ids[] = {
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{ .compatible = "microsoft,ftpm" },
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{ }
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};
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MODULE_DEVICE_TABLE(of, of_ftpm_tee_ids);
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static struct platform_driver ftpm_tee_driver = {
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.driver = {
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.name = "ftpm-tee",
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.of_match_table = of_match_ptr(of_ftpm_tee_ids),
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},
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.probe = ftpm_tee_probe,
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.remove = ftpm_tee_remove,
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};
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module_platform_driver(ftpm_tee_driver);
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MODULE_AUTHOR("Thirupathaiah Annapureddy <thiruan@microsoft.com>");
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MODULE_DESCRIPTION("TPM Driver for fTPM TA in TEE");
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MODULE_LICENSE("GPL v2");
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40
drivers/char/tpm/tpm_ftpm_tee.h
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40
drivers/char/tpm/tpm_ftpm_tee.h
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@ -0,0 +1,40 @@
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/* SPDX-License-Identifier: GPL-2.0 */
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/*
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* Copyright (C) Microsoft Corporation
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*/
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#ifndef __TPM_FTPM_TEE_H__
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#define __TPM_FTPM_TEE_H__
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#include <linux/tee_drv.h>
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#include <linux/tpm.h>
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#include <linux/uuid.h>
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/* The TAFs ID implemented in this TA */
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#define FTPM_OPTEE_TA_SUBMIT_COMMAND (0)
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#define FTPM_OPTEE_TA_EMULATE_PPI (1)
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/* max. buffer size supported by fTPM */
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#define MAX_COMMAND_SIZE 4096
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#define MAX_RESPONSE_SIZE 4096
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/**
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* struct ftpm_tee_private - fTPM's private data
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* @chip: struct tpm_chip instance registered with tpm framework.
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* @state: internal state
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* @session: fTPM TA session identifier.
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* @resp_len: cached response buffer length.
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* @resp_buf: cached response buffer.
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* @ctx: TEE context handler.
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* @shm: Memory pool shared with fTPM TA in TEE.
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*/
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struct ftpm_tee_private {
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struct tpm_chip *chip;
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u32 session;
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size_t resp_len;
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u8 resp_buf[MAX_RESPONSE_SIZE];
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struct tee_context *ctx;
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struct tee_shm *shm;
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};
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#endif /* __TPM_FTPM_TEE_H__ */
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