xref: /openbmc/u-boot/drivers/tee/sandbox.c (revision be381cc4)
1 // SPDX-License-Identifier: GPL-2.0+
2 /*
3  * Copyright (C) 2018 Linaro Limited
4  */
5 #include <common.h>
6 #include <dm.h>
7 #include <sandboxtee.h>
8 #include <tee.h>
9 #include <tee/optee_ta_avb.h>
10 
11 /*
12  * The sandbox tee driver tries to emulate a generic Trusted Exectution
13  * Environment (TEE) with the Trusted Application (TA) OPTEE_TA_AVB
14  * available.
15  */
16 
17 /**
18  * struct ta_entry - TA entries
19  * @uuid:		UUID of an emulated TA
20  * @open_session	Called when a session is openened to the TA
21  * @invoke_func		Called when a function in the TA is to be invoked
22  *
23  * This struct is used to register TAs in this sandbox emulation of a TEE.
24  */
25 struct ta_entry {
26 	struct tee_optee_ta_uuid uuid;
27 	u32 (*open_session)(uint num_params, struct tee_param *params);
28 	u32 (*invoke_func)(u32 func, uint num_params, struct tee_param *params);
29 };
30 
31 #ifdef CONFIG_OPTEE_TA_AVB
32 static u32 get_attr(uint n, uint num_params, struct tee_param *params)
33 {
34 	if (n >= num_params)
35 		return TEE_PARAM_ATTR_TYPE_NONE;
36 
37 	return params[n].attr;
38 }
39 
40 static u32 check_params(u8 p0, u8 p1, u8 p2, u8 p3, uint num_params,
41 			struct tee_param *params)
42 {
43 	u8 p[] = { p0, p1, p2, p3};
44 	uint n;
45 
46 	for (n = 0; n < ARRAY_SIZE(p); n++)
47 		if (p[n] != get_attr(n, num_params, params))
48 			goto bad_params;
49 
50 	for (; n < num_params; n++)
51 		if (get_attr(n, num_params, params))
52 			goto bad_params;
53 
54 	return TEE_SUCCESS;
55 
56 bad_params:
57 	printf("Bad param attrs\n");
58 
59 	return TEE_ERROR_BAD_PARAMETERS;
60 }
61 
62 static u64 ta_avb_rollback_indexes[TA_AVB_MAX_ROLLBACK_LOCATIONS];
63 static u32 ta_avb_lock_state;
64 
65 static u32 ta_avb_open_session(uint num_params, struct tee_param *params)
66 {
67 	/*
68 	 * We don't expect additional parameters when opening a session to
69 	 * this TA.
70 	 */
71 	return check_params(TEE_PARAM_ATTR_TYPE_NONE, TEE_PARAM_ATTR_TYPE_NONE,
72 			    TEE_PARAM_ATTR_TYPE_NONE, TEE_PARAM_ATTR_TYPE_NONE,
73 			    num_params, params);
74 }
75 
76 static u32 ta_avb_invoke_func(u32 func, uint num_params,
77 			      struct tee_param *params)
78 {
79 	u32 res;
80 	uint slot;
81 	u64 val;
82 
83 	switch (func) {
84 	case TA_AVB_CMD_READ_ROLLBACK_INDEX:
85 		res = check_params(TEE_PARAM_ATTR_TYPE_VALUE_INPUT,
86 				   TEE_PARAM_ATTR_TYPE_VALUE_OUTPUT,
87 				   TEE_PARAM_ATTR_TYPE_NONE,
88 				   TEE_PARAM_ATTR_TYPE_NONE,
89 				   num_params, params);
90 		if (res)
91 			return res;
92 
93 		slot = params[0].u.value.a;
94 		if (slot >= ARRAY_SIZE(ta_avb_rollback_indexes)) {
95 			printf("Rollback index slot out of bounds %u\n", slot);
96 			return TEE_ERROR_BAD_PARAMETERS;
97 		}
98 
99 		val = ta_avb_rollback_indexes[slot];
100 		params[1].u.value.a = val >> 32;
101 		params[1].u.value.b = val;
102 		return TEE_SUCCESS;
103 
104 	case TA_AVB_CMD_WRITE_ROLLBACK_INDEX:
105 		res = check_params(TEE_PARAM_ATTR_TYPE_VALUE_INPUT,
106 				   TEE_PARAM_ATTR_TYPE_VALUE_INPUT,
107 				   TEE_PARAM_ATTR_TYPE_NONE,
108 				   TEE_PARAM_ATTR_TYPE_NONE,
109 				   num_params, params);
110 		if (res)
111 			return res;
112 
113 		slot = params[0].u.value.a;
114 		if (slot >= ARRAY_SIZE(ta_avb_rollback_indexes)) {
115 			printf("Rollback index slot out of bounds %u\n", slot);
116 			return TEE_ERROR_BAD_PARAMETERS;
117 		}
118 
119 		val = (u64)params[1].u.value.a << 32 | params[1].u.value.b;
120 		if (val < ta_avb_rollback_indexes[slot])
121 			return TEE_ERROR_SECURITY;
122 
123 		ta_avb_rollback_indexes[slot] = val;
124 		return TEE_SUCCESS;
125 
126 	case TA_AVB_CMD_READ_LOCK_STATE:
127 		res = check_params(TEE_PARAM_ATTR_TYPE_VALUE_OUTPUT,
128 				   TEE_PARAM_ATTR_TYPE_NONE,
129 				   TEE_PARAM_ATTR_TYPE_NONE,
130 				   TEE_PARAM_ATTR_TYPE_NONE,
131 				   num_params, params);
132 		if (res)
133 			return res;
134 
135 		params[0].u.value.a = ta_avb_lock_state;
136 		return TEE_SUCCESS;
137 
138 	case TA_AVB_CMD_WRITE_LOCK_STATE:
139 		res = check_params(TEE_PARAM_ATTR_TYPE_VALUE_INPUT,
140 				   TEE_PARAM_ATTR_TYPE_NONE,
141 				   TEE_PARAM_ATTR_TYPE_NONE,
142 				   TEE_PARAM_ATTR_TYPE_NONE,
143 				   num_params, params);
144 		if (res)
145 			return res;
146 
147 		if (ta_avb_lock_state != params[0].u.value.a) {
148 			ta_avb_lock_state = params[0].u.value.a;
149 			memset(ta_avb_rollback_indexes, 0,
150 			       sizeof(ta_avb_rollback_indexes));
151 		}
152 
153 		return TEE_SUCCESS;
154 
155 	default:
156 		return TEE_ERROR_NOT_SUPPORTED;
157 	}
158 }
159 #endif /*OPTEE_TA_AVB*/
160 
161 static const struct ta_entry ta_entries[] = {
162 #ifdef CONFIG_OPTEE_TA_AVB
163 	{ .uuid = TA_AVB_UUID,
164 	  .open_session = ta_avb_open_session,
165 	  .invoke_func = ta_avb_invoke_func,
166 	},
167 #endif
168 };
169 
170 static void sandbox_tee_get_version(struct udevice *dev,
171 				    struct tee_version_data *vers)
172 {
173 	struct tee_version_data v = {
174 		.gen_caps = TEE_GEN_CAP_GP | TEE_GEN_CAP_REG_MEM,
175 	};
176 
177 	*vers = v;
178 }
179 
180 static int sandbox_tee_close_session(struct udevice *dev, u32 session)
181 {
182 	struct sandbox_tee_state *state = dev_get_priv(dev);
183 
184 	if (!state->ta || state->session != session)
185 		return -EINVAL;
186 
187 	state->session = 0;
188 	state->ta = NULL;
189 
190 	return 0;
191 }
192 
193 static const struct ta_entry *find_ta_entry(u8 uuid[TEE_UUID_LEN])
194 {
195 	struct tee_optee_ta_uuid u;
196 	uint n;
197 
198 	tee_optee_ta_uuid_from_octets(&u, uuid);
199 
200 	for (n = 0; n < ARRAY_SIZE(ta_entries); n++)
201 		if (!memcmp(&u, &ta_entries[n].uuid, sizeof(u)))
202 			return ta_entries + n;
203 
204 	return NULL;
205 }
206 
207 static int sandbox_tee_open_session(struct udevice *dev,
208 				    struct tee_open_session_arg *arg,
209 				    uint num_params, struct tee_param *params)
210 {
211 	struct sandbox_tee_state *state = dev_get_priv(dev);
212 	const struct ta_entry *ta;
213 
214 	if (state->ta) {
215 		printf("A session is already open\n");
216 		return -EBUSY;
217 	}
218 
219 	ta = find_ta_entry(arg->uuid);
220 	if (!ta) {
221 		printf("Cannot find TA\n");
222 		arg->ret = TEE_ERROR_ITEM_NOT_FOUND;
223 		arg->ret_origin = TEE_ORIGIN_TEE;
224 
225 		return 0;
226 	}
227 
228 	arg->ret = ta->open_session(num_params, params);
229 	arg->ret_origin = TEE_ORIGIN_TRUSTED_APP;
230 
231 	if (!arg->ret) {
232 		state->ta = (void *)ta;
233 		state->session = 1;
234 		arg->session = state->session;
235 	} else {
236 		printf("Cannot open session, TA returns error\n");
237 	}
238 
239 	return 0;
240 }
241 
242 static int sandbox_tee_invoke_func(struct udevice *dev,
243 				   struct tee_invoke_arg *arg,
244 				   uint num_params, struct tee_param *params)
245 {
246 	struct sandbox_tee_state *state = dev_get_priv(dev);
247 	struct ta_entry *ta = state->ta;
248 
249 	if (!arg->session) {
250 		printf("Missing session\n");
251 		return -EINVAL;
252 	}
253 
254 	if (!ta) {
255 		printf("TA session not available\n");
256 		return -EINVAL;
257 	}
258 
259 	if (arg->session != state->session) {
260 		printf("Session mismatch\n");
261 		return -EINVAL;
262 	}
263 
264 	arg->ret = ta->invoke_func(arg->func, num_params, params);
265 	arg->ret_origin = TEE_ORIGIN_TRUSTED_APP;
266 
267 	return 0;
268 }
269 
270 static int sandbox_tee_shm_register(struct udevice *dev, struct tee_shm *shm)
271 {
272 	struct sandbox_tee_state *state = dev_get_priv(dev);
273 
274 	state->num_shms++;
275 
276 	return 0;
277 }
278 
279 static int sandbox_tee_shm_unregister(struct udevice *dev, struct tee_shm *shm)
280 {
281 	struct sandbox_tee_state *state = dev_get_priv(dev);
282 
283 	state->num_shms--;
284 
285 	return 0;
286 }
287 
288 static const struct tee_driver_ops sandbox_tee_ops = {
289 	.get_version = sandbox_tee_get_version,
290 	.open_session = sandbox_tee_open_session,
291 	.close_session = sandbox_tee_close_session,
292 	.invoke_func = sandbox_tee_invoke_func,
293 	.shm_register = sandbox_tee_shm_register,
294 	.shm_unregister = sandbox_tee_shm_unregister,
295 };
296 
297 static const struct udevice_id sandbox_tee_match[] = {
298 	{ .compatible = "sandbox,tee" },
299 	{},
300 };
301 
302 U_BOOT_DRIVER(sandbox_tee) = {
303 	.name = "sandbox_tee",
304 	.id = UCLASS_TEE,
305 	.of_match = sandbox_tee_match,
306 	.ops = &sandbox_tee_ops,
307 	.priv_auto_alloc_size = sizeof(struct sandbox_tee_state),
308 };
309