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authorThirupathaiah Annapureddy <thiruan@linux.microsoft.com>2020-01-12 23:34:22 -0800
committerSimon Glass <sjg@chromium.org>2020-02-05 19:33:46 -0700
commit8d73be7a8e47ee57efe57ee17ed393bac1011fce (patch)
treef346d1c10ec37b895db90cb5e03a60c7134cedfc /drivers/tpm/tpm2_ftpm_tee.c
parent19464f4feb70292ea857c332f06673ac840a007d (diff)
tpm2: ftpm: 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 Signed-off-by: Thirupathaiah Annapureddy <thiruan@linux.microsoft.com>
Diffstat (limited to 'drivers/tpm/tpm2_ftpm_tee.c')
-rw-r--r--drivers/tpm/tpm2_ftpm_tee.c250
1 files changed, 250 insertions, 0 deletions
diff --git a/drivers/tpm/tpm2_ftpm_tee.c b/drivers/tpm/tpm2_ftpm_tee.c
new file mode 100644
index 0000000000..4b79d4ada0
--- /dev/null
+++ b/drivers/tpm/tpm2_ftpm_tee.c
@@ -0,0 +1,250 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) Microsoft Corporation
+ *
+ * Authors:
+ * Thirupathaiah Annapureddy <thiruan@microsoft.com>
+ *
+ * Description:
+ * Device Driver for 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 <common.h>
+#include <dm.h>
+#include <tpm-v2.h>
+#include <tee.h>
+
+#include "tpm_tis.h"
+#include "tpm2_ftpm_tee.h"
+
+/**
+ * ftpm_tee_transceive() - send fTPM commands and retrieve fTPM response.
+ * @sendbuf - address of the data to send, byte by byte
+ * @send_size - length of the data to send
+ * @recvbuf - address where to read the response, byte by byte.
+ * @recv_len - pointer to the size of buffer
+ *
+ * Return:
+ * In case of success, returns 0.
+ * On failure, -errno
+ */
+static int ftpm_tee_transceive(struct udevice *dev, const u8 *sendbuf,
+ size_t send_size, u8 *recvbuf,
+ size_t *recv_len)
+{
+ struct ftpm_tee_private *context = dev_get_priv(dev);
+ int rc = 0;
+ size_t resp_len;
+ u8 *resp_buf;
+ struct tpm_output_header *resp_header;
+ struct tee_invoke_arg transceive_args;
+ struct tee_param command_params[4];
+ struct tee_shm *shm;
+
+ if (send_size > MAX_COMMAND_SIZE) {
+ debug("%s:send_size=%zd exceeds MAX_COMMAND_SIZE\n",
+ __func__, send_size);
+ return -EIO;
+ }
+
+ shm = context->shm;
+ memset(&transceive_args, 0, sizeof(transceive_args));
+ memset(command_params, 0, sizeof(command_params));
+
+ /* Invoke FTPM_OPTEE_TA_SUBMIT_COMMAND function of fTPM TA */
+ transceive_args = (struct tee_invoke_arg) {
+ .func = FTPM_OPTEE_TA_SUBMIT_COMMAND,
+ .session = context->session,
+ };
+
+ /* Fill FTPM_OPTEE_TA_SUBMIT_COMMAND parameters */
+ /* request */
+ command_params[0] = (struct tee_param) {
+ .attr = TEE_PARAM_ATTR_TYPE_MEMREF_INPUT,
+ .u.memref = {
+ .shm = shm,
+ .size = send_size,
+ .shm_offs = 0,
+ },
+ };
+ memset(command_params[0].u.memref.shm->addr, 0,
+ (MAX_COMMAND_SIZE + MAX_RESPONSE_SIZE));
+ memcpy(command_params[0].u.memref.shm->addr, sendbuf, send_size);
+
+ /* response */
+ command_params[1] = (struct tee_param) {
+ .attr = TEE_PARAM_ATTR_TYPE_MEMREF_INOUT,
+ .u.memref = {
+ .shm = shm,
+ .size = MAX_RESPONSE_SIZE,
+ .shm_offs = MAX_COMMAND_SIZE,
+ },
+ };
+
+ rc = tee_invoke_func(context->tee_dev, &transceive_args, 4,
+ command_params);
+ if ((rc < 0) || (transceive_args.ret != 0)) {
+ debug("%s:SUBMIT_COMMAND invoke error: 0x%x\n",
+ __func__, transceive_args.ret);
+ return (rc < 0) ? rc : transceive_args.ret;
+ }
+
+ resp_buf = command_params[1].u.memref.shm->addr +
+ command_params[1].u.memref.shm_offs;
+ resp_header = (struct tpm_output_header *)resp_buf;
+ resp_len = be32_to_cpu(resp_header->length);
+
+ /* sanity check resp_len*/
+ if (resp_len < TPM_HEADER_SIZE) {
+ debug("%s:tpm response header too small\n", __func__);
+ return -EIO;
+ }
+ if (resp_len > MAX_RESPONSE_SIZE) {
+ debug("%s:resp_len=%zd exceeds MAX_RESPONSE_SIZE\n",
+ __func__, resp_len);
+ return -EIO;
+ }
+ if (resp_len > *recv_len) {
+ debug("%s:response length is bigger than receive buffer\n",
+ __func__);
+ return -EIO;
+ }
+
+ /* sanity checks look good, copy the response */
+ memcpy(recvbuf, resp_buf, resp_len);
+ *recv_len = resp_len;
+
+ return 0;
+}
+
+static int ftpm_tee_open(struct udevice *dev)
+{
+ struct ftpm_tee_private *context = dev_get_priv(dev);
+
+ if (context->is_open)
+ return -EBUSY;
+
+ context->is_open = 1;
+
+ return 0;
+}
+
+static int ftpm_tee_close(struct udevice *dev)
+{
+ struct ftpm_tee_private *context = dev_get_priv(dev);
+
+ if (context->is_open)
+ context->is_open = 0;
+
+ return 0;
+}
+
+static int ftpm_tee_desc(struct udevice *dev, char *buf, int size)
+{
+ if (size < 32)
+ return -ENOSPC;
+
+ return snprintf(buf, size, "Microsoft OP-TEE fTPM");
+}
+
+static int ftpm_tee_match(struct tee_version_data *vers, const void *data)
+{
+ debug("%s:vers->gen_caps =0x%x\n", __func__, vers->gen_caps);
+
+ /*
+ * Currently this driver only support GP Complaint OPTEE based fTPM TA
+ */
+ return vers->gen_caps & TEE_GEN_CAP_GP;
+}
+
+static int ftpm_tee_probe(struct udevice *dev)
+{
+ int rc;
+ struct tpm_chip_priv *priv = dev_get_uclass_priv(dev);
+ struct ftpm_tee_private *context = dev_get_priv(dev);
+ struct tee_open_session_arg sess_arg;
+ const struct tee_optee_ta_uuid uuid = TA_FTPM_UUID;
+
+ memset(context, 0, sizeof(*context));
+
+ /* Use the TPM v2 stack */
+ priv->version = TPM_V2;
+ priv->pcr_count = 24;
+ priv->pcr_select_min = 3;
+
+ /* Find TEE device */
+ context->tee_dev = tee_find_device(NULL, ftpm_tee_match, NULL, NULL);
+ if (!context->tee_dev) {
+ debug("%s:tee_find_device failed\n", __func__);
+ return -ENODEV;
+ }
+
+ /* Open a session with the fTPM TA */
+ memset(&sess_arg, 0, sizeof(sess_arg));
+ tee_optee_ta_uuid_to_octets(sess_arg.uuid, &uuid);
+
+ rc = tee_open_session(context->tee_dev, &sess_arg, 0, NULL);
+ if ((rc < 0) || (sess_arg.ret != 0)) {
+ debug("%s:tee_open_session failed, err=%x\n",
+ __func__, sess_arg.ret);
+ return -EIO;
+ }
+ context->session = sess_arg.session;
+
+ /* Allocate dynamic shared memory with fTPM TA */
+ rc = tee_shm_alloc(context->tee_dev,
+ MAX_COMMAND_SIZE + MAX_RESPONSE_SIZE,
+ 0, &context->shm);
+ if (rc) {
+ debug("%s:tee_shm_alloc failed with rc = %d\n", __func__, rc);
+ goto out_shm_alloc;
+ }
+
+ return 0;
+
+out_shm_alloc:
+ tee_close_session(context->tee_dev, context->session);
+
+ return rc;
+}
+
+static int ftpm_tee_remove(struct udevice *dev)
+{
+ struct ftpm_tee_private *context = dev_get_priv(dev);
+ int rc;
+
+ /* tee_pre_remove frees any leftover TEE shared memory */
+
+ /* close the existing session with fTPM TA*/
+ rc = tee_close_session(context->tee_dev, context->session);
+ debug("%s: tee_close_session - rc =%d\n", __func__, rc);
+
+ return 0;
+}
+
+static const struct tpm_ops ftpm_tee_ops = {
+ .open = ftpm_tee_open,
+ .close = ftpm_tee_close,
+ .get_desc = ftpm_tee_desc,
+ .xfer = ftpm_tee_transceive,
+};
+
+static const struct udevice_id ftpm_tee_ids[] = {
+ { .compatible = "microsoft,ftpm" },
+ { }
+};
+
+U_BOOT_DRIVER(ftpm_tee) = {
+ .name = "ftpm_tee",
+ .id = UCLASS_TPM,
+ .of_match = ftpm_tee_ids,
+ .ops = &ftpm_tee_ops,
+ .probe = ftpm_tee_probe,
+ .remove = ftpm_tee_remove,
+ .flags = DM_FLAG_OS_PREPARE,
+ .priv_auto_alloc_size = sizeof(struct ftpm_tee_private),
+};