Merge tag 'tpmdd-next-20190902' of git://git.infradead.org/users/jjs/linux-tpmdd

Pull tpm updates from Jarkko Sakkinen:
 "A new driver for fTPM living inside ARM TEE was added this round.

  In addition to that, there are three bug fixes and one clean up"

* tag 'tpmdd-next-20190902' of git://git.infradead.org/users/jjs/linux-tpmdd:
  tpm/tpm_ftpm_tee: Document fTPM TEE driver
  tpm/tpm_ftpm_tee: A driver for firmware TPM running inside TEE
  tpm: Remove a deprecated comments about implicit sysfs locking
  tpm_tis_core: Set TPM_CHIP_FLAG_IRQ before probing for interrupts
  tpm_tis_core: Turn on the TPM before probing IRQ's
  MAINTAINERS: fix style in KEYS-TRUSTED entry

Documentation/devicetree/bindings/vendor-prefixes.yaml

@@ -575,6 +575,8 @@ patternProperties:
     description: Micro Crystal AG
   "^micron,.*":
     description: Micron Technology Inc.
+  "^microsoft,.*":
+    description: Microsoft Corporation
   "^mikroe,.*":
     description: MikroElektronika d.o.o.
   "^miniand,.*":

Documentation/security/tpm/index.rst

@@ -6,3 +6,4 @@ Trusted Platform Module documentation
 
    tpm_vtpm_proxy
    xen-tpmfront
+   tpm_ftpm_tee

Documentation/security/tpm/tpm_ftpm_tee.rst

+=============================================
+Firmware TPM Driver
+=============================================
+
+This document describes the firmware Trusted Platform Module (fTPM)
+device driver.
+
+Introduction
+============
+
+This driver is a shim for firmware implemented in ARM's TrustZone
+environment. The driver allows programs to interact with the TPM in the same
+way they 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.

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 firmware TPM running in TEE.
 
 source "drivers/char/tpm/st33zp24/Kconfig"
 endif # TCG_TPM

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

drivers/char/tpm/tpm-chip.c

@@ -287,12 +287,9 @@ static void tpm_devs_release(struct device *dev)
  * @dev: device to which the chip is associated.
  *
  * Issues a TPM2_Shutdown command prior to loss of power, as required by the
- * TPM 2.0 spec.
- * Then, calls bus- and device- specific shutdown code.
+ * TPM 2.0 spec. Then, calls bus- and device- specific shutdown code.
  *
- * XXX: This codepath relies on the fact that sysfs is not enabled for
- * TPM2: sysfs uses an implicit lock on chip->ops, so this could race if TPM2
- * has sysfs support enabled before TPM sysfs's implicit locking is fixed.
+ * Return: always 0 (i.e. success)
  */
 static int tpm_class_shutdown(struct device *dev)
 {

drivers/char/tpm/tpm-sysfs.c

@@ -329,16 +329,9 @@ static const struct attribute_group tpm_dev_group = {
 
 void tpm_sysfs_add_device(struct tpm_chip *chip)
 {
-	/* XXX: If you wish to remove this restriction, you must first update
-	 * tpm_sysfs to explicitly lock chip->ops.
-	 */
 	if (chip->flags & TPM_CHIP_FLAG_TPM2)
 		return;
 
-	/* The sysfs routines rely on an implicit tpm_try_get_ops, device_del
-	 * is called before ops is null'd and the sysfs core synchronizes this
-	 * removal so that no callbacks are running or can run again
-	 */
 	WARN_ON(chip->groups_cnt != 0);
 	chip->groups[chip->groups_cnt++] = &tpm_dev_group;
 }

drivers/char/tpm/tpm_ftpm_tee.c

+// 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 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;
+}
+
+/**
+ * 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 (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));
+	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 always.
+ */
+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 = "ftpm-tee",
+		.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");

drivers/char/tpm/tpm_ftpm_tee.h

+/* 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__ */

drivers/char/tpm/tpm_tis_core.c

@@ -980,6 +980,8 @@ int tpm_tis_core_init(struct device *dev, struct tpm_tis_data *priv, int irq,
 			goto out_err;
 		}
 
+		tpm_chip_start(chip);
+		chip->flags |= TPM_CHIP_FLAG_IRQ;
 		if (irq) {
 			tpm_tis_probe_irq_single(chip, intmask, IRQF_SHARED,
 						 irq);
@@ -989,6 +991,7 @@ int tpm_tis_core_init(struct device *dev, struct tpm_tis_data *priv, int irq,
 		} else {
 			tpm_tis_probe_irq(chip, intmask);
 		}
+		tpm_chip_stop(chip);
 	}
 
 	rc = tpm_chip_register(chip);