On Mon, Apr 15, 2019 at 11:56:35AM -0400, Sasha Levin 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-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 The commit message should include at least a brief description what TEE is. > > Signed-off-by: Thirupathaiah Annapureddy <thiruan@xxxxxxxxxxxxx> > Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> > --- > drivers/char/tpm/Kconfig | 5 + > drivers/char/tpm/Makefile | 1 + > drivers/char/tpm/tpm_ftpm_tee.c | 366 ++++++++++++++++++++++++++++++++ > drivers/char/tpm/tpm_ftpm_tee.h | 47 ++++ > 4 files changed, 419 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 536e55d3919f..5638726641eb 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 > + ---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..f33cdfeb5376 > --- /dev/null > +++ b/drivers/char/tpm/tpm_ftpm_tee.c > @@ -0,0 +1,366 @@ > +// SPDX-License-Identifier: GPL-2.0 > +/* > + * Copyright (C) Microsoft Corporation > + */ There should be at least some description what kind of implementation this is and something about TEE. > + > +#include <linux/of.h> > +#include <linux/of_platform.h> > +#include <linux/acpi.h> > +#include <linux/platform_device.h> > +#include <linux/tee_drv.h> > +#include <linux/uuid.h> > +#include <linux/tpm.h> > + > +#include "tpm.h" > +#include "tpm_ftpm_tee.h" > + > +#define DRIVER_NAME "ftpm-tee" > + > +/* TA_FTPM_UUID: BC50D971-D4C9-42C4-82CB-343FB7F37896 */ > +static const uuid_t ftpm_ta_uuid = > + UUID_INIT(0xBC50D971, 0xD4C9, 0x42C4, > + 0x82, 0xCB, 0x34, 0x3F, 0xB7, 0xF3, 0x78, 0x96); Just wondering why prefixes are here in different order in the comment and code. > + > +/* > + * Note: ftpm_tee_tpm_op_recv and ftpm_tee_tpm_op_send are called from the > + * same routine tpm_try_transmit in tpm-interface.c. These calls are protected > + * by chip->tpm_mutex => There is no need for protecting any data shared > + * between these routines ex: struct ftpm_tee_private > + */ This documentation block should be removed. It could be in all drivers and thus this documentation belongs outside of specific HW drivers. > + > +/** > + * ftpm_tee_tpm_op_recv retrieve fTPM response. > + * @param: chip, the tpm_chip description as specified in driver/char/tpm/tpm.h. > + * @param: buf, the buffer to store data. > + * @param: count, the number of bytes to read. > + * @return: In case of success the number of bytes received. > + * In other case, a < 0 value describing the issue. > + */ This should be modified to follow kdoc [1]. It is inconsistent with the other kdoc comments we have. Now it is all wrong and contains redundant information. It should be something like /** * ftpm_tee_tpm_op_recv() - retrieve a response from fTPM * @chip: TPM chip associated with the fTPM * @buf: buffer for the received data * @count: number of bytes to read * * Copy the response from fTPM's internal buffer to the buffer provided * by the caller. * * Return: * 0 on success, * -errno on error */ > +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. > + * > + * @param: chip, the tpm_chip description as specified in driver/char/tpm/tpm.h > + * @param: buf, the buffer to send. > + * @param: len, the number of bytes to send. > + * @return: In case of success, returns 0. > + * In other case, a < 0 value describing the issue. > + */ This should be modified to follow kdoc [1]. It is inconsistent with the other kdoc comments we have. > +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 > + * @param: pdev, the platform_device description. > + * @return: 0 in case of success. > + * or a negative value describing the error. > + */ > +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__); > + 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 > + * @param: 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@xxxxxxxxxxxxx>"); > +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..9de513e72dbb > --- /dev/null > +++ b/drivers/char/tpm/tpm_ftpm_tee.h > @@ -0,0 +1,47 @@ > +// 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/uuid.h> > +#include <linux/tpm.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; > +}; > + > +/* > + * Note: ftpm_tee_tpm_op_recv and ftpm_tee_tpm_op_send are called from the > + * same routine tpm_try_transmit in tpm-interface.c. These calls are protected > + * by chip->tpm_mutex => There is no need for protecting any data shared > + * between these routines ex: struct ftpm_tee_private > + */ This comment should be removed. > + > +#endif /* __TPM_FTPM_TEE_H__ */ > -- > 2.19.1 > [1] https://www.kernel.org/doc/Documentation/kernel-doc-nano-HOWTO.txt /Jarkko
