drivers/tee/sandbox.c

// SPDX-License-Identifier: GPL-2.0+
/*
 * Copyright (C) 2018 Linaro Limited
 */

#include <dm.h>
#include <sandboxtee.h>
#include <tee.h>
#include <tee/optee_ta_avb.h>
#include <tee/optee_ta_rpc_test.h>
#include <tee/optee_ta_scp03.h>

#include "optee/optee_msg.h"
#include "optee/optee_private.h"

/*
 * The sandbox tee driver tries to emulate a generic Trusted Execution
 * Environment (TEE) with the Trusted Applications (TA) OPTEE_TA_AVB and
 * OPTEE_TA_RPC_TEST available.
 */

static const u32 pstorage_max = 16;
/**
 * struct ta_entry - TA entries
 * @uuid:		UUID of an emulated TA
 * @open_session	Called when a session is opened to the TA
 * @invoke_func		Called when a function in the TA is to be invoked
 *
 * This struct is used to register TAs in this sandbox emulation of a TEE.
 */
struct ta_entry {
	struct tee_optee_ta_uuid uuid;
	u32 (*open_session)(struct udevice *dev, uint num_params,
			    struct tee_param *params);
	u32 (*invoke_func)(struct udevice *dev,
			   u32 func, uint num_params,
			   struct tee_param *params);
};

static int get_msg_arg(struct udevice *dev, uint num_params,
		       struct tee_shm **shmp, struct optee_msg_arg **msg_arg)
{
	int rc;
	struct optee_msg_arg *ma;

	rc = __tee_shm_add(dev, OPTEE_MSG_NONCONTIG_PAGE_SIZE, NULL,
			   OPTEE_MSG_GET_ARG_SIZE(num_params), TEE_SHM_ALLOC,
			   shmp);
	if (rc)
		return rc;

	ma = (*shmp)->addr;
	memset(ma, 0, OPTEE_MSG_GET_ARG_SIZE(num_params));
	ma->num_params = num_params;
	*msg_arg = ma;

	return 0;
}

void *optee_alloc_and_init_page_list(void *buf, ulong len,
				     u64 *phys_buf_ptr)
{
	/*
	 * An empty stub is added just to fix linking issues.
	 * This function isn't supposed to be called in sandbox
	 * setup, otherwise replace this with a proper
	 * implementation from optee/core.c
	 */
	return NULL;
}

#if defined(CONFIG_OPTEE_TA_SCP03) || defined(CONFIG_OPTEE_TA_AVB)
static u32 get_attr(uint n, uint num_params, struct tee_param *params)
{
	if (n >= num_params)
		return TEE_PARAM_ATTR_TYPE_NONE;

	return params[n].attr;
}

static u32 check_params(u8 p0, u8 p1, u8 p2, u8 p3, uint num_params,
			struct tee_param *params)
{
	u8 p[] = { p0, p1, p2, p3 };
	uint n;

	for (n = 0; n < ARRAY_SIZE(p); n++)
		if (p[n] != get_attr(n, num_params, params))
			goto bad_params;

	for (; n < num_params; n++)
		if (get_attr(n, num_params, params))
			goto bad_params;

	return TEE_SUCCESS;

bad_params:
	printf("Bad param attrs\n");

	return TEE_ERROR_BAD_PARAMETERS;
}
#endif

#ifdef CONFIG_OPTEE_TA_SCP03
static u32 pta_scp03_open_session(struct udevice *dev, uint num_params,
				  struct tee_param *params)
{
	/*
	 * We don't expect additional parameters when opening a session to
	 * this TA.
	 */
	return check_params(TEE_PARAM_ATTR_TYPE_NONE, TEE_PARAM_ATTR_TYPE_NONE,
			    TEE_PARAM_ATTR_TYPE_NONE, TEE_PARAM_ATTR_TYPE_NONE,
			    num_params, params);
}

static u32 pta_scp03_invoke_func(struct udevice *dev, u32 func, uint num_params,
				 struct tee_param *params)
{
	u32 res;
	static bool enabled;
	static bool provisioned;

	switch (func) {
	case PTA_CMD_ENABLE_SCP03:
		res = check_params(TEE_PARAM_ATTR_TYPE_VALUE_INPUT,
				   TEE_PARAM_ATTR_TYPE_NONE,
				   TEE_PARAM_ATTR_TYPE_NONE,
				   TEE_PARAM_ATTR_TYPE_NONE,
				   num_params, params);
		if (res)
			return res;

		/* If SCP03 was not enabled, enable it */
		if (!enabled)
			enabled = true;

		/* If SCP03 was not provisioned, provision new keys */
		if (params[0].u.value.a && !provisioned)
			provisioned = true;

		/*
		 * Either way, we assume both operations succeeded and that
		 * the communication channel has now been established
		 */

		return TEE_SUCCESS;
	default:
		return TEE_ERROR_NOT_SUPPORTED;
	}
}
#endif

#ifdef CONFIG_OPTEE_TA_AVB
static u32 ta_avb_open_session(struct udevice *dev, uint num_params,
			       struct tee_param *params)
{
	/*
	 * We don't expect additional parameters when opening a session to
	 * this TA.
	 */
	return check_params(TEE_PARAM_ATTR_TYPE_NONE, TEE_PARAM_ATTR_TYPE_NONE,
			    TEE_PARAM_ATTR_TYPE_NONE, TEE_PARAM_ATTR_TYPE_NONE,
			    num_params, params);
}

static u32 ta_avb_invoke_func(struct udevice *dev, u32 func, uint num_params,
			      struct tee_param *params)
{
	struct sandbox_tee_state *state = dev_get_priv(dev);
	struct env_entry e, *ep;
	char *name;
	u32 res;
	uint slot;
	u64 val;
	char *value;
	u32 value_sz, tmp_sz;

	switch (func) {
	case TA_AVB_CMD_READ_ROLLBACK_INDEX:
		res = check_params(TEE_PARAM_ATTR_TYPE_VALUE_INPUT,
				   TEE_PARAM_ATTR_TYPE_VALUE_OUTPUT,
				   TEE_PARAM_ATTR_TYPE_NONE,
				   TEE_PARAM_ATTR_TYPE_NONE,
				   num_params, params);
		if (res)
			return res;

		slot = params[0].u.value.a;
		if (slot >= ARRAY_SIZE(state->ta_avb_rollback_indexes)) {
			printf("Rollback index slot out of bounds %u\n", slot);
			return TEE_ERROR_BAD_PARAMETERS;
		}

		val = state->ta_avb_rollback_indexes[slot];
		params[1].u.value.a = val >> 32;
		params[1].u.value.b = val;
		return TEE_SUCCESS;

	case TA_AVB_CMD_WRITE_ROLLBACK_INDEX:
		res = check_params(TEE_PARAM_ATTR_TYPE_VALUE_INPUT,
				   TEE_PARAM_ATTR_TYPE_VALUE_INPUT,
				   TEE_PARAM_ATTR_TYPE_NONE,
				   TEE_PARAM_ATTR_TYPE_NONE,
				   num_params, params);
		if (res)
			return res;

		slot = params[0].u.value.a;
		if (slot >= ARRAY_SIZE(state->ta_avb_rollback_indexes)) {
			printf("Rollback index slot out of bounds %u\n", slot);
			return TEE_ERROR_BAD_PARAMETERS;
		}

		val = (u64)params[1].u.value.a << 32 | params[1].u.value.b;
		if (val < state->ta_avb_rollback_indexes[slot])
			return TEE_ERROR_SECURITY;

		state->ta_avb_rollback_indexes[slot] = val;
		return TEE_SUCCESS;

	case TA_AVB_CMD_READ_LOCK_STATE:
		res = check_params(TEE_PARAM_ATTR_TYPE_VALUE_OUTPUT,
				   TEE_PARAM_ATTR_TYPE_NONE,
				   TEE_PARAM_ATTR_TYPE_NONE,
				   TEE_PARAM_ATTR_TYPE_NONE,
				   num_params, params);
		if (res)
			return res;

		params[0].u.value.a = state->ta_avb_lock_state;
		return TEE_SUCCESS;

	case TA_AVB_CMD_WRITE_LOCK_STATE:
		res = check_params(TEE_PARAM_ATTR_TYPE_VALUE_INPUT,
				   TEE_PARAM_ATTR_TYPE_NONE,
				   TEE_PARAM_ATTR_TYPE_NONE,
				   TEE_PARAM_ATTR_TYPE_NONE,
				   num_params, params);
		if (res)
			return res;

		if (state->ta_avb_lock_state != params[0].u.value.a) {
			state->ta_avb_lock_state = params[0].u.value.a;
			memset(state->ta_avb_rollback_indexes, 0,
			       sizeof(state->ta_avb_rollback_indexes));
		}

		return TEE_SUCCESS;
	case TA_AVB_CMD_READ_PERSIST_VALUE:
		res = check_params(TEE_PARAM_ATTR_TYPE_MEMREF_INPUT,
				   TEE_PARAM_ATTR_TYPE_MEMREF_INOUT,
				   TEE_PARAM_ATTR_TYPE_NONE,
				   TEE_PARAM_ATTR_TYPE_NONE,
				   num_params, params);
		if (res)
			return res;

		name = params[0].u.memref.shm->addr;

		value = params[1].u.memref.shm->addr;
		value_sz = params[1].u.memref.size;

		e.key = name;
		e.data = NULL;
		hsearch_r(e, ENV_FIND, &ep, &state->pstorage_htab, 0);
		if (!ep)
			return TEE_ERROR_ITEM_NOT_FOUND;

		tmp_sz = strlen(ep->data) + 1;
		if (value_sz < tmp_sz)
			return TEE_ERROR_SHORT_BUFFER;

		memcpy(value, ep->data, tmp_sz);
		params[1].u.memref.size = tmp_sz;

		return TEE_SUCCESS;
	case TA_AVB_CMD_WRITE_PERSIST_VALUE:
		res = check_params(TEE_PARAM_ATTR_TYPE_MEMREF_INPUT,
				   TEE_PARAM_ATTR_TYPE_MEMREF_INPUT,
				   TEE_PARAM_ATTR_TYPE_NONE,
				   TEE_PARAM_ATTR_TYPE_NONE,
				   num_params, params);
		if (res)
			return res;

		name = params[0].u.memref.shm->addr;

		value = params[1].u.memref.shm->addr;
		value_sz = params[1].u.memref.size;

		e.key = name;
		e.data = NULL;
		hsearch_r(e, ENV_FIND, &ep, &state->pstorage_htab, 0);
		if (ep)
			hdelete_r(e.key, &state->pstorage_htab, 0);

		e.key = name;
		e.data = value;
		hsearch_r(e, ENV_ENTER, &ep, &state->pstorage_htab, 0);
		if (!ep)
			return TEE_ERROR_OUT_OF_MEMORY;

		return TEE_SUCCESS;

	default:
		return TEE_ERROR_NOT_SUPPORTED;
	}
}
#endif /* OPTEE_TA_AVB */

#ifdef CONFIG_OPTEE_TA_RPC_TEST
static u32 ta_rpc_test_open_session(struct udevice *dev, uint num_params,
				    struct tee_param *params)
{
	/*
	 * We don't expect additional parameters when opening a session to
	 * this TA.
	 */
	return check_params(TEE_PARAM_ATTR_TYPE_NONE, TEE_PARAM_ATTR_TYPE_NONE,
			    TEE_PARAM_ATTR_TYPE_NONE, TEE_PARAM_ATTR_TYPE_NONE,
			    num_params, params);
}

static void fill_i2c_rpc_params(struct optee_msg_arg *msg_arg, u64 bus_num,
				u64 chip_addr, u64 xfer_flags, u64 op,
				struct tee_param_memref memref)
{
	msg_arg->params[0].attr = OPTEE_MSG_ATTR_TYPE_VALUE_INPUT;
	msg_arg->params[1].attr = OPTEE_MSG_ATTR_TYPE_VALUE_INPUT;
	msg_arg->params[2].attr = OPTEE_MSG_ATTR_TYPE_RMEM_INOUT;
	msg_arg->params[3].attr = OPTEE_MSG_ATTR_TYPE_VALUE_OUTPUT;

	/* trigger I2C services of TEE supplicant */
	msg_arg->cmd = OPTEE_MSG_RPC_CMD_I2C_TRANSFER;

	msg_arg->params[0].u.value.a = op;
	msg_arg->params[0].u.value.b = bus_num;
	msg_arg->params[0].u.value.c = chip_addr;
	msg_arg->params[1].u.value.a = xfer_flags;

	/* buffer to read/write data */
	msg_arg->params[2].u.rmem.shm_ref = (ulong)memref.shm;
	msg_arg->params[2].u.rmem.size = memref.size;
	msg_arg->params[2].u.rmem.offs = memref.shm_offs;

	msg_arg->num_params = 4;
}

static u32 ta_rpc_test_invoke_func(struct udevice *dev, u32 func,
				   uint num_params,
				   struct tee_param *params)
{
	struct tee_shm *shm;
	struct tee_param_memref memref_data;
	struct optee_msg_arg *msg_arg;
	int chip_addr, bus_num, op, xfer_flags;
	int res;

	res = check_params(TEE_PARAM_ATTR_TYPE_VALUE_INPUT,
			   TEE_PARAM_ATTR_TYPE_MEMREF_INOUT,
			   TEE_PARAM_ATTR_TYPE_NONE,
			   TEE_PARAM_ATTR_TYPE_NONE,
			   num_params, params);
	if (res)
		return TEE_ERROR_BAD_PARAMETERS;

	bus_num = params[0].u.value.a;
	chip_addr = params[0].u.value.b;
	xfer_flags = params[0].u.value.c;
	memref_data = params[1].u.memref;

	switch (func) {
	case TA_RPC_TEST_CMD_I2C_READ:
		op = OPTEE_MSG_RPC_CMD_I2C_TRANSFER_RD;
		break;
	case TA_RPC_TEST_CMD_I2C_WRITE:
		op = OPTEE_MSG_RPC_CMD_I2C_TRANSFER_WR;
		break;
	default:
		return TEE_ERROR_NOT_SUPPORTED;
	}

	/*
	 * Fill params for an RPC call to tee supplicant
	 */
	res = get_msg_arg(dev, 4, &shm, &msg_arg);
	if (res)
		goto out;

	fill_i2c_rpc_params(msg_arg, bus_num, chip_addr, xfer_flags, op,
			    memref_data);

	/* Make an RPC call to tee supplicant */
	optee_suppl_cmd(dev, shm, 0);
	res = msg_arg->ret;
out:
	tee_shm_free(shm);

	return res;
}
#endif /* CONFIG_OPTEE_TA_RPC_TEST */

static const struct ta_entry ta_entries[] = {
#ifdef CONFIG_OPTEE_TA_AVB
	{ .uuid = TA_AVB_UUID,
	  .open_session = ta_avb_open_session,
	  .invoke_func = ta_avb_invoke_func,
	},
#endif
#ifdef CONFIG_OPTEE_TA_RPC_TEST
	{ .uuid = TA_RPC_TEST_UUID,
	  .open_session = ta_rpc_test_open_session,
	  .invoke_func = ta_rpc_test_invoke_func,
	},
#endif
#ifdef CONFIG_OPTEE_TA_SCP03
	{ .uuid = PTA_SCP03_UUID,
	  .open_session = pta_scp03_open_session,
	  .invoke_func = pta_scp03_invoke_func,
	},
#endif
};

static void sandbox_tee_get_version(struct udevice *dev,
				    struct tee_version_data *vers)
{
	struct tee_version_data v = {
		.gen_caps = TEE_GEN_CAP_GP | TEE_GEN_CAP_REG_MEM,
	};

	*vers = v;
}

static int sandbox_tee_close_session(struct udevice *dev, u32 session)
{
	struct sandbox_tee_state *state = dev_get_priv(dev);

	if (!state->ta || state->session != session)
		return -EINVAL;

	state->session = 0;
	state->ta = NULL;

	return 0;
}

static const struct ta_entry *find_ta_entry(u8 uuid[TEE_UUID_LEN])
{
	struct tee_optee_ta_uuid u;
	uint n;

	tee_optee_ta_uuid_from_octets(&u, uuid);

	for (n = 0; n < ARRAY_SIZE(ta_entries); n++)
		if (!memcmp(&u, &ta_entries[n].uuid, sizeof(u)))
			return ta_entries + n;

	return NULL;
}

static int sandbox_tee_open_session(struct udevice *dev,
				    struct tee_open_session_arg *arg,
				    uint num_params, struct tee_param *params)
{
	struct sandbox_tee_state *state = dev_get_priv(dev);
	const struct ta_entry *ta;

	if (state->ta) {
		printf("A session is already open\n");
		return -EBUSY;
	}

	ta = find_ta_entry(arg->uuid);
	if (!ta) {
		printf("Cannot find TA\n");
		arg->ret = TEE_ERROR_ITEM_NOT_FOUND;
		arg->ret_origin = TEE_ORIGIN_TEE;

		return 0;
	}

	arg->ret = ta->open_session(dev, num_params, params);
	arg->ret_origin = TEE_ORIGIN_TRUSTED_APP;

	if (!arg->ret) {
		state->ta = (void *)ta;
		state->session = 1;
		arg->session = state->session;
	} else {
		printf("Cannot open session, TA returns error\n");
	}

	return 0;
}

static int sandbox_tee_invoke_func(struct udevice *dev,
				   struct tee_invoke_arg *arg,
				   uint num_params, struct tee_param *params)
{
	struct sandbox_tee_state *state = dev_get_priv(dev);
	struct ta_entry *ta = state->ta;

	if (!arg->session) {
		printf("Missing session\n");
		return -EINVAL;
	}

	if (!ta) {
		printf("TA session not available\n");
		return -EINVAL;
	}

	if (arg->session != state->session) {
		printf("Session mismatch\n");
		return -EINVAL;
	}

	arg->ret = ta->invoke_func(dev, arg->func, num_params, params);
	arg->ret_origin = TEE_ORIGIN_TRUSTED_APP;

	return 0;
}

static int sandbox_tee_shm_register(struct udevice *dev, struct tee_shm *shm)
{
	struct sandbox_tee_state *state = dev_get_priv(dev);

	state->num_shms++;

	return 0;
}

static int sandbox_tee_shm_unregister(struct udevice *dev, struct tee_shm *shm)
{
	struct sandbox_tee_state *state = dev_get_priv(dev);

	state->num_shms--;

	return 0;
}

static int sandbox_tee_remove(struct udevice *dev)
{
	struct sandbox_tee_state *state = dev_get_priv(dev);

	hdestroy_r(&state->pstorage_htab);

	return 0;
}

static int sandbox_tee_probe(struct udevice *dev)
{
	struct sandbox_tee_state *state = dev_get_priv(dev);
	/*
	 * With this hastable we emulate persistent storage,
	 * which should contain persistent values
	 * between different sessions/command invocations.
	 */
	if (!hcreate_r(pstorage_max, &state->pstorage_htab))
		return TEE_ERROR_OUT_OF_MEMORY;

	return 0;
}

static const struct tee_driver_ops sandbox_tee_ops = {
	.get_version = sandbox_tee_get_version,
	.open_session = sandbox_tee_open_session,
	.close_session = sandbox_tee_close_session,
	.invoke_func = sandbox_tee_invoke_func,
	.shm_register = sandbox_tee_shm_register,
	.shm_unregister = sandbox_tee_shm_unregister,
};

static const struct udevice_id sandbox_tee_match[] = {
	{ .compatible = "sandbox,tee" },
	{},
};

U_BOOT_DRIVER(sandbox_tee) = {
	.name = "sandbox_tee",
	.id = UCLASS_TEE,
	.of_match = sandbox_tee_match,
	.ops = &sandbox_tee_ops,
	.priv_auto	= sizeof(struct sandbox_tee_state),
	.probe = sandbox_tee_probe,
	.remove = sandbox_tee_remove,
};