tee: add sandbox driver

Adds a sandbox tee driver which emulates a generic TEE with the OP-TEE
AVB TA.

Reviewed-by: Simon Glass <sjg@chromium.org>
Signed-off-by: Jens Wiklander <jens.wiklander@linaro.org>
Reviewed-by: Simon Glass <sjg@chromium.org>
[trini: Fix printf warnings in ta_avb_invoke_func, slots is uint]
Signed-off-by: Tom Rini <trini@konsulko.com>

drivers/tee/Kconfig

@@ -1,8 +1,8 @@
 # Generic Trusted Execution Environment Configuration
 config TEE
 	bool "Trusted Execution Environment support"
-	depends on ARM && (ARM64 || CPU_V7A)
-	select ARM_SMCCC
+	depends on (ARM && (ARM64 || CPU_V7A)) || SANDBOX
+	select ARM_SMCCC if ARM
 	help
 	  This implements a generic interface towards a Trusted Execution
 	  Environment (TEE). A TEE is a trusted OS running in some secure
@@ -14,6 +14,20 @@ if TEE
 
 menu "TEE drivers"
 
+config SANDBOX_TEE
+	bool "Sandbox TEE emulator"
+	depends on SANDBOX
+	default y
+	help
+	  This emulates a generic TEE needed for testing including the AVB
+	  TA. The emulation provides all callbacks of a regular TEE and
+	  supports session and shared memory management. The AVB TA is
+	  emulated with rollback indexes and device lock-state, the state
+	  of the TA is only kept in RAM and will be reset on each boot.
+	  The emulation only supports one open session at a time.
+	  Interaction from the U-Boot command line in possible via the
+	  "avb" commands.
+
 source "drivers/tee/optee/Kconfig"
 
 endmenu

drivers/tee/Makefile

@@ -1,4 +1,5 @@
 # SPDX-License-Identifier: GPL-2.0+
 
 obj-y += tee-uclass.o
+obj-$(CONFIG_SANDBOX) += sandbox.o
 obj-$(CONFIG_OPTEE) += optee/

drivers/tee/optee/Kconfig

@@ -10,7 +10,7 @@ config OPTEE
 	  handle Remote Procedure Calls (RPC) from OP-TEE needed to
 	  execute a service. For more information see: https://www.op-tee.org
 
-if OPTEE
+if OPTEE || SANDBOX
 
 menu "OP-TEE options"
 

drivers/tee/sandbox.c

@@ -0,0 +1,308 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Copyright (C) 2018 Linaro Limited
+ */
+#include <common.h>
+#include <dm.h>
+#include <sandboxtee.h>
+#include <tee.h>
+#include <tee/optee_ta_avb.h>
+
+/*
+ * The sandbox tee driver tries to emulate a generic Trusted Exectution
+ * Environment (TEE) with the Trusted Application (TA) OPTEE_TA_AVB
+ * available.
+ */
+
+/**
+ * struct ta_entry - TA entries
+ * @uuid:		UUID of an emulated TA
+ * @open_session	Called when a session is openened 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)(uint num_params, struct tee_param *params);
+	u32 (*invoke_func)(u32 func, uint num_params, struct tee_param *params);
+};
+
+#ifdef 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;
+}
+
+static u64 ta_avb_rollback_indexes[TA_AVB_MAX_ROLLBACK_LOCATIONS];
+static u32 ta_avb_lock_state;
+
+static u32 ta_avb_open_session(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(u32 func, uint num_params,
+			      struct tee_param *params)
+{
+	u32 res;
+	uint slot;
+	u64 val;
+
+	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(ta_avb_rollback_indexes)) {
+			printf("Rollback index slot out of bounds %u\n", slot);
+			return TEE_ERROR_BAD_PARAMETERS;
+		}
+
+		val = 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(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 < ta_avb_rollback_indexes[slot])
+			return TEE_ERROR_SECURITY;
+
+		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 = 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 (ta_avb_lock_state != params[0].u.value.a) {
+			ta_avb_lock_state = params[0].u.value.a;
+			memset(ta_avb_rollback_indexes, 0,
+			       sizeof(ta_avb_rollback_indexes));
+		}
+
+		return TEE_SUCCESS;
+
+	default:
+		return TEE_ERROR_NOT_SUPPORTED;
+	}
+}
+#endif /*OPTEE_TA_AVB*/
+
+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
+};
+
+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(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(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 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_alloc_size = sizeof(struct sandbox_tee_state),
+};

include/sandboxtee.h

@@ -0,0 +1,21 @@
+/* SPDX-License-Identifier: GPL-2.0+ */
+/*
+ * Copyright (C) 2018 Linaro Limited
+ */
+
+#ifndef __SANDBOXTEE_H
+#define __SANDBOXTEE_H
+
+/**
+ * struct sandbox_tee_state - internal state of the sandbox TEE
+ * @session:	current open session
+ * @num_shms:	number of registered shared memory objects
+ * @ta:		Trusted Application of current session
+ */
+struct sandbox_tee_state {
+	u32 session;
+	int num_shms;
+	void *ta;
+};
+
+#endif /*__SANDBOXTEE_H*/