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* [PATCH v5 0/2] fTPM: firmware TPM running in TEE
@ 2019-06-14 20:21 Sasha Levin
  2019-06-14 20:21 ` [PATCH v5 1/2] " Sasha Levin
  2019-06-14 20:21 ` [PATCH v5 2/2] fTPM: add documentation for ftpm driver Sasha Levin
  0 siblings, 2 replies; 4+ messages in thread
From: Sasha Levin @ 2019-06-14 20:21 UTC (permalink / raw)
  To: peterhuewe, jarkko.sakkinen, jgg
  Cc: corbet, linux-kernel, linux-doc, linux-integrity, linux-kernel,
	thiruan, bryankel, tee-dev, Sasha Levin

Changes from v4:

 - Don't show an error message while waiting for OP-TEE to come up.

Sasha Levin (2):
  fTPM: firmware TPM running in TEE
  fTPM: add documentation for ftpm driver

 Documentation/security/tpm/index.rst        |   1 +
 Documentation/security/tpm/tpm_ftpm_tee.rst |  31 ++
 drivers/char/tpm/Kconfig                    |   5 +
 drivers/char/tpm/Makefile                   |   1 +
 drivers/char/tpm/tpm_ftpm_tee.c             | 382 ++++++++++++++++++++
 drivers/char/tpm/tpm_ftpm_tee.h             |  40 ++
 6 files changed, 460 insertions(+)
 create mode 100644 Documentation/security/tpm/tpm_ftpm_tee.rst
 create mode 100644 drivers/char/tpm/tpm_ftpm_tee.c
 create mode 100644 drivers/char/tpm/tpm_ftpm_tee.h

-- 
2.20.1


^ permalink raw reply	[flat|nested] 4+ messages in thread

* [PATCH v5 1/2] fTPM: firmware TPM running in TEE
  2019-06-14 20:21 [PATCH v5 0/2] fTPM: firmware TPM running in TEE Sasha Levin
@ 2019-06-14 20:21 ` " Sasha Levin
  2019-06-19 11:05   ` Ilias Apalodimas
  2019-06-14 20:21 ` [PATCH v5 2/2] fTPM: add documentation for ftpm driver Sasha Levin
  1 sibling, 1 reply; 4+ messages in thread
From: Sasha Levin @ 2019-06-14 20:21 UTC (permalink / raw)
  To: peterhuewe, jarkko.sakkinen, jgg
  Cc: corbet, linux-kernel, linux-doc, linux-integrity, linux-kernel,
	thiruan, bryankel, tee-dev, Sasha Levin

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-implementation-tpm-chip/ .

As well as reference code for the firmware available here:
https://github.com/Microsoft/ms-tpm-20-ref/tree/master/Samples/ARM32-FirmwareTPM

Tested-by: Thirupathaiah Annapureddy <thiruan@microsoft.com>
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 | 382 ++++++++++++++++++++++++++++++++
 drivers/char/tpm/tpm_ftpm_tee.h |  40 ++++
 4 files changed, 428 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 88a3c06fc153..facee3bb5607 100644
--- a/drivers/char/tpm/Kconfig
+++ b/drivers/char/tpm/Kconfig
@@ -164,6 +164,11 @@ 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 TEE
 
 source "drivers/char/tpm/st33zp24/Kconfig"
 endif # TCG_TPM
diff --git a/drivers/char/tpm/Makefile b/drivers/char/tpm/Makefile
index a01c4cab902a..c354cdff9c62 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 000000000000..2bfa5b1d4c06
--- /dev/null
+++ b/drivers/char/tpm/tpm_ftpm_tee.c
@@ -0,0 +1,382 @@
+// 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"
+
+#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:
+ * 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 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;
+	else
+		return 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)) {
+		if (ERR_PTR(pvt_data->ctx) == -ENOENT)
+			return -EPROBE_DEFER;
+		dev_err(dev, "%s:tee_client_open_context failed\n", __func__);
+		return ERR_PTR(pvt_data->ctx);
+	}
+
+	/* 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 000000000000..b09ee7be4545
--- /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


^ permalink raw reply	[flat|nested] 4+ messages in thread

* [PATCH v5 2/2] fTPM: add documentation for ftpm driver
  2019-06-14 20:21 [PATCH v5 0/2] fTPM: firmware TPM running in TEE Sasha Levin
  2019-06-14 20:21 ` [PATCH v5 1/2] " Sasha Levin
@ 2019-06-14 20:21 ` Sasha Levin
  1 sibling, 0 replies; 4+ messages in thread
From: Sasha Levin @ 2019-06-14 20:21 UTC (permalink / raw)
  To: peterhuewe, jarkko.sakkinen, jgg
  Cc: corbet, linux-kernel, linux-doc, linux-integrity, linux-kernel,
	thiruan, bryankel, tee-dev, Sasha Levin

This patch adds basic documentation to describe the new fTPM driver.

Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 Documentation/security/tpm/index.rst        |  1 +
 Documentation/security/tpm/tpm_ftpm_tee.rst | 31 +++++++++++++++++++++
 2 files changed, 32 insertions(+)
 create mode 100644 Documentation/security/tpm/tpm_ftpm_tee.rst

diff --git a/Documentation/security/tpm/index.rst b/Documentation/security/tpm/index.rst
index af77a7bbb070..15783668644f 100644
--- a/Documentation/security/tpm/index.rst
+++ b/Documentation/security/tpm/index.rst
@@ -4,4 +4,5 @@ Trusted Platform Module documentation
 
 .. toctree::
 
+   tpm_ftpm_tee
    tpm_vtpm_proxy
diff --git a/Documentation/security/tpm/tpm_ftpm_tee.rst b/Documentation/security/tpm/tpm_ftpm_tee.rst
new file mode 100644
index 000000000000..29c2f8b5ed10
--- /dev/null
+++ b/Documentation/security/tpm/tpm_ftpm_tee.rst
@@ -0,0 +1,31 @@
+=============================================
+Firmware TPM Driver
+=============================================
+
+| Authors:
+| Thirupathaiah Annapureddy <thiruan@microsoft.com>
+| Sasha Levin <sashal@kernel.org>
+
+This document describes the firmware Trusted Platform Module (fTPM)
+device driver.
+
+Introduction
+============
+
+This driver is a shim for a firmware implemented in ARM's TrustZone
+environment. The driver allows programs to interact with the TPM in the same
+way the would interact with a hardware TPM.
+
+Design
+======
+
+The driver acts as a thin layer that passes commands to and from a TPM
+implemented in firmware. The driver itself doesn't contain much logic and is
+used more like a dumb pipe between firmware and kernel/userspace.
+
+The firmware itself is based on the following paper:
+https://www.microsoft.com/en-us/research/wp-content/uploads/2017/06/ftpm1.pdf
+
+When the driver is loaded it will expose ``/dev/tpmX`` character devices to
+userspace which will enable userspace to communicate with the firmware tpm
+through this device.
-- 
2.20.1


^ permalink raw reply	[flat|nested] 4+ messages in thread

* Re: [PATCH v5 1/2] fTPM: firmware TPM running in TEE
  2019-06-14 20:21 ` [PATCH v5 1/2] " Sasha Levin
@ 2019-06-19 11:05   ` Ilias Apalodimas
  0 siblings, 0 replies; 4+ messages in thread
From: Ilias Apalodimas @ 2019-06-19 11:05 UTC (permalink / raw)
  To: Sasha Levin
  Cc: peterhuewe, jarkko.sakkinen, jgg, corbet, linux-kernel,
	linux-doc, linux-integrity, linux-kernel, thiruan, bryankel,
	tee-dev

Hi Sasha, 

Can you please include me and Sumit in future iterations of this?
We've both commented and did some testing, we'd prefer not scanning the mailing
list for new versions.

[...]
> +// 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"
> +
> +#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:
> + * 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 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;
> +	else
> +		return 0;
> +}
> +
> +/*
> + * Undo what has been done in ftpm_tee_probe
> + */
> +static void ftpm_tee_deinit(struct ftpm_tee_private *pvt_data)
I don't see this functions being used anywhere and my compiler complains. 
ftpm_tee_remove() is doing similar things, should this one be removed?

> +{
> +	/* 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)) {
> +		if (ERR_PTR(pvt_data->ctx) == -ENOENT)
> +			return -EPROBE_DEFER;
> +		dev_err(dev, "%s:tee_client_open_context failed\n", __func__);
> +		return ERR_PTR(pvt_data->ctx);
> +	}
> +
> +	/* 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 000000000000..b09ee7be4545
> --- /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
> 

Regards
/Ilias

^ permalink raw reply	[flat|nested] 4+ messages in thread

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Thread overview: 4+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2019-06-14 20:21 [PATCH v5 0/2] fTPM: firmware TPM running in TEE Sasha Levin
2019-06-14 20:21 ` [PATCH v5 1/2] " Sasha Levin
2019-06-19 11:05   ` Ilias Apalodimas
2019-06-14 20:21 ` [PATCH v5 2/2] fTPM: add documentation for ftpm driver Sasha Levin

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