On Thu, 30 May 2019 at 20:58, Sasha Levin sashal@kernel.org wrote:
This patch adds support for a software-only implementation of a TPM running in TEE.
There is extensive documentation of the design here: https://www.microsoft.com/en-us/research/publication/ftpm-software-implement... .
As well as reference code for the firmware available here: https://github.com/Microsoft/ms-tpm-20-ref/tree/master/Samples/ARM32-Firmwar...
Signed-off-by: Thirupathaiah Annapureddy thiruan@microsoft.com Signed-off-by: Sasha Levin sashal@kernel.org
drivers/char/tpm/Kconfig | 5 + drivers/char/tpm/Makefile | 1 + drivers/char/tpm/tpm_ftpm_tee.c | 380 ++++++++++++++++++++++++++++++++ drivers/char/tpm/tpm_ftpm_tee.h | 40 ++++ 4 files changed, 426 insertions(+) create mode 100644 drivers/char/tpm/tpm_ftpm_tee.c create mode 100644 drivers/char/tpm/tpm_ftpm_tee.h
diff --git a/drivers/char/tpm/Kconfig b/drivers/char/tpm/Kconfig index f3e4bc490cf05..8bc9a56cade14 100644 --- a/drivers/char/tpm/Kconfig +++ b/drivers/char/tpm/Kconfig @@ -163,6 +163,11 @@ config TCG_VTPM_PROXY /dev/vtpmX and a server-side file descriptor on which the vTPM can receive commands.
+config TCG_FTPM_TEE
tristate "TEE based fTPM Interface"depends on TEE && OPTEE---help---This driver proxies for fTPM running in TEEsource "drivers/char/tpm/st33zp24/Kconfig" endif # TCG_TPM diff --git a/drivers/char/tpm/Makefile b/drivers/char/tpm/Makefile index a01c4cab902a6..c354cdff9c625 100644 --- a/drivers/char/tpm/Makefile +++ b/drivers/char/tpm/Makefile @@ -33,3 +33,4 @@ obj-$(CONFIG_TCG_TIS_ST33ZP24) += st33zp24/ obj-$(CONFIG_TCG_XEN) += xen-tpmfront.o obj-$(CONFIG_TCG_CRB) += tpm_crb.o obj-$(CONFIG_TCG_VTPM_PROXY) += tpm_vtpm_proxy.o +obj-$(CONFIG_TCG_FTPM_TEE) += tpm_ftpm_tee.o diff --git a/drivers/char/tpm/tpm_ftpm_tee.c b/drivers/char/tpm/tpm_ftpm_tee.c new file mode 100644 index 0000000000000..f926b1287988b --- /dev/null +++ b/drivers/char/tpm/tpm_ftpm_tee.c @@ -0,0 +1,380 @@ +// SPDX-License-Identifier: GPL-2.0 +/*
- Copyright (C) Microsoft Corporation
- Implements a firmware TPM as described here:
- A reference implementation is available here:
- */
+#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"
+#define DRIVER_NAME "ftpm-tee"
+/*
- 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:
- */
+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 0;+}
+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;elsereturn 0;+}
+/*
- Undo what has been done in ftpm_tee_probe
- */
+static void ftpm_tee_deinit(struct ftpm_tee_private *pvt_data) +{
/* Release the chip */tpm_chip_unregister(pvt_data->chip);/* frees chip */if (pvt_data->chip)put_device(&pvt_data->chip->dev);if (pvt_data->ctx) {/* 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 */+}
+/**
- ftpm_tee_probe - initialize the fTPM
- @pdev: the platform_device description.
- Return:
On success, 0. On failure, -errno.- */
+static int ftpm_tee_probe(struct platform_device *pdev) +{
int rc;struct tpm_chip *chip;struct device *dev = &pdev->dev;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)) {dev_err(dev, "%s:tee_client_open_context failed\n", __func__);
Is this well tested? I see this misleading error multiple times as follows although TEE driver works pretty well.
Module built with "CONFIG_TCG_FTPM_TEE=y"
[ 1.436878] ftpm-tee tpm@0: ftpm_tee_probe:tee_client_open_context failed [ 1.509471] ftpm-tee tpm@0: ftpm_tee_probe:tee_client_open_context failed [ 1.517268] ftpm-tee tpm@0: ftpm_tee_probe:tee_client_open_context failed [ 1.525596] ftpm-tee tpm@0: ftpm_tee_probe:tee_client_open_context failed
-Sumit
return -EPROBE_DEFER;}/* Open a session with fTPM TA */memset(&sess_arg, 0, sizeof(sess_arg));memcpy(sess_arg.uuid, ftpm_ta_uuid.b, TEE_IOCTL_UUID_LEN);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(pvt_data->ctx,(MAX_COMMAND_SIZE + MAX_RESPONSE_SIZE),TEE_SHM_MAPPED | TEE_SHM_DMA_BUF);if (IS_ERR(pvt_data->shm)) {dev_err(dev, "%s:tee_shm_alloc 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;+}
+/**
- ftpm_tee_remove - remove the TPM device
- @pdev: the platform_device description.
- Return:
0 in case of success.- */
+static int ftpm_tee_remove(struct platform_device *pdev) +{
struct ftpm_tee_private *pvt_data = dev_get_drvdata(&pdev->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 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_driver = {
.driver = {.name = DRIVER_NAME,.of_match_table = of_match_ptr(of_ftpm_tee_ids),},.probe = ftpm_tee_probe,.remove = ftpm_tee_remove,+};
+module_platform_driver(ftpm_tee_driver);
+MODULE_AUTHOR("Thirupathaiah Annapureddy thiruan@microsoft.com"); +MODULE_DESCRIPTION("TPM Driver for fTPM TA in TEE"); +MODULE_LICENSE("GPL v2"); diff --git a/drivers/char/tpm/tpm_ftpm_tee.h b/drivers/char/tpm/tpm_ftpm_tee.h new file mode 100644 index 0000000000000..b09ee7be45459 --- /dev/null +++ b/drivers/char/tpm/tpm_ftpm_tee.h @@ -0,0 +1,40 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +/*
- Copyright (C) Microsoft Corporation
- */
+#ifndef __TPM_FTPM_TEE_H__ +#define __TPM_FTPM_TEE_H__
+#include <linux/tee_drv.h> +#include <linux/tpm.h> +#include <linux/uuid.h>
+/* 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 data
- @chip: struct tpm_chip instance registered with tpm framework.
- @state: internal state
- @session: fTPM TA session identifier.
- @resp_len: cached response buffer length.
- @resp_buf: cached response buffer.
- @ctx: TEE context handler.
- @shm: Memory pool shared with fTPM TA in TEE.
- */
+struct ftpm_tee_private {
struct tpm_chip *chip;u32 session;size_t resp_len;u8 resp_buf[MAX_RESPONSE_SIZE];struct tee_context *ctx;struct tee_shm *shm;+};
+#endif /* __TPM_FTPM_TEE_H__ */
2.20.1