1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * Copyright (C) 2019-2021 Linaro Ltd.
4 *
5 * Author:
6 * Sumit Garg <sumit.garg@linaro.org>
7 */
8
9 #include <linux/err.h>
10 #include <linux/key-type.h>
11 #include <linux/module.h>
12 #include <linux/slab.h>
13 #include <linux/string.h>
14 #include <linux/tee_drv.h>
15 #include <linux/uuid.h>
16
17 #include <keys/trusted_tee.h>
18
19 #define DRIVER_NAME "trusted-key-tee"
20
21 /*
22 * Get random data for symmetric key
23 *
24 * [out] memref[0] Random data
25 */
26 #define TA_CMD_GET_RANDOM 0x0
27
28 /*
29 * Seal trusted key using hardware unique key
30 *
31 * [in] memref[0] Plain key
32 * [out] memref[1] Sealed key datablob
33 */
34 #define TA_CMD_SEAL 0x1
35
36 /*
37 * Unseal trusted key using hardware unique key
38 *
39 * [in] memref[0] Sealed key datablob
40 * [out] memref[1] Plain key
41 */
42 #define TA_CMD_UNSEAL 0x2
43
44 /**
45 * struct trusted_key_tee_private - TEE Trusted key private data
46 * @dev: TEE based Trusted key device.
47 * @ctx: TEE context handler.
48 * @session_id: Trusted key TA session identifier.
49 * @shm_pool: Memory pool shared with TEE device.
50 */
51 struct trusted_key_tee_private {
52 struct device *dev;
53 struct tee_context *ctx;
54 u32 session_id;
55 struct tee_shm *shm_pool;
56 };
57
58 static struct trusted_key_tee_private pvt_data;
59
60 /*
61 * Have the TEE seal(encrypt) the symmetric key
62 */
63 static int trusted_tee_seal(struct trusted_key_payload *p, char *datablob)
64 {
65 int ret;
66 struct tee_ioctl_invoke_arg inv_arg;
67 struct tee_param param[4];
68 struct tee_shm *reg_shm = NULL;
69
70 memset(&inv_arg, 0, sizeof(inv_arg));
71 memset(¶m, 0, sizeof(param));
72
73 reg_shm = tee_shm_register_kernel_buf(pvt_data.ctx, p->key,
74 sizeof(p->key) + sizeof(p->blob));
75 if (IS_ERR(reg_shm)) {
76 dev_err(pvt_data.dev, "shm register failed\n");
77 return PTR_ERR(reg_shm);
78 }
79
80 inv_arg.func = TA_CMD_SEAL;
81 inv_arg.session = pvt_data.session_id;
82 inv_arg.num_params = 4;
83
84 param[0].attr = TEE_IOCTL_PARAM_ATTR_TYPE_MEMREF_INPUT;
85 param[0].u.memref.shm = reg_shm;
86 param[0].u.memref.size = p->key_len;
87 param[0].u.memref.shm_offs = 0;
88 param[1].attr = TEE_IOCTL_PARAM_ATTR_TYPE_MEMREF_OUTPUT;
89 param[1].u.memref.shm = reg_shm;
90 param[1].u.memref.size = sizeof(p->blob);
91 param[1].u.memref.shm_offs = sizeof(p->key);
92
93 ret = tee_client_invoke_func(pvt_data.ctx, &inv_arg, param);
94 if ((ret < 0) || (inv_arg.ret != 0)) {
95 dev_err(pvt_data.dev, "TA_CMD_SEAL invoke err: %x\n",
96 inv_arg.ret);
97 ret = -EFAULT;
98 } else {
99 p->blob_len = param[1].u.memref.size;
100 }
101
102 tee_shm_free(reg_shm);
103
104 return ret;
105 }
106
107 /*
108 * Have the TEE unseal(decrypt) the symmetric key
109 */
110 static int trusted_tee_unseal(struct trusted_key_payload *p, char *datablob)
111 {
112 int ret;
113 struct tee_ioctl_invoke_arg inv_arg;
114 struct tee_param param[4];
115 struct tee_shm *reg_shm = NULL;
116
117 memset(&inv_arg, 0, sizeof(inv_arg));
118 memset(¶m, 0, sizeof(param));
119
120 reg_shm = tee_shm_register_kernel_buf(pvt_data.ctx, p->key,
121 sizeof(p->key) + sizeof(p->blob));
122 if (IS_ERR(reg_shm)) {
123 dev_err(pvt_data.dev, "shm register failed\n");
124 return PTR_ERR(reg_shm);
125 }
126
127 inv_arg.func = TA_CMD_UNSEAL;
128 inv_arg.session = pvt_data.session_id;
129 inv_arg.num_params = 4;
130
131 param[0].attr = TEE_IOCTL_PARAM_ATTR_TYPE_MEMREF_INPUT;
132 param[0].u.memref.shm = reg_shm;
133 param[0].u.memref.size = p->blob_len;
134 param[0].u.memref.shm_offs = sizeof(p->key);
135 param[1].attr = TEE_IOCTL_PARAM_ATTR_TYPE_MEMREF_OUTPUT;
136 param[1].u.memref.shm = reg_shm;
137 param[1].u.memref.size = sizeof(p->key);
138 param[1].u.memref.shm_offs = 0;
139
140 ret = tee_client_invoke_func(pvt_data.ctx, &inv_arg, param);
141 if ((ret < 0) || (inv_arg.ret != 0)) {
142 dev_err(pvt_data.dev, "TA_CMD_UNSEAL invoke err: %x\n",
143 inv_arg.ret);
144 ret = -EFAULT;
145 } else {
146 p->key_len = param[1].u.memref.size;
147 }
148
149 tee_shm_free(reg_shm);
150
151 return ret;
152 }
153
154 /*
155 * Have the TEE generate random symmetric key
156 */
157 static int trusted_tee_get_random(unsigned char *key, size_t key_len)
158 {
159 int ret;
160 struct tee_ioctl_invoke_arg inv_arg;
161 struct tee_param param[4];
162 struct tee_shm *reg_shm = NULL;
163
164 memset(&inv_arg, 0, sizeof(inv_arg));
165 memset(¶m, 0, sizeof(param));
166
167 reg_shm = tee_shm_register_kernel_buf(pvt_data.ctx, key, key_len);
168 if (IS_ERR(reg_shm)) {
169 dev_err(pvt_data.dev, "key shm register failed\n");
170 return PTR_ERR(reg_shm);
171 }
172
173 inv_arg.func = TA_CMD_GET_RANDOM;
174 inv_arg.session = pvt_data.session_id;
175 inv_arg.num_params = 4;
176
177 param[0].attr = TEE_IOCTL_PARAM_ATTR_TYPE_MEMREF_OUTPUT;
178 param[0].u.memref.shm = reg_shm;
179 param[0].u.memref.size = key_len;
180 param[0].u.memref.shm_offs = 0;
181
182 ret = tee_client_invoke_func(pvt_data.ctx, &inv_arg, param);
183 if ((ret < 0) || (inv_arg.ret != 0)) {
184 dev_err(pvt_data.dev, "TA_CMD_GET_RANDOM invoke err: %x\n",
185 inv_arg.ret);
186 ret = -EFAULT;
187 } else {
188 ret = param[0].u.memref.size;
189 }
190
191 tee_shm_free(reg_shm);
192
193 return ret;
194 }
195
196 static int optee_ctx_match(struct tee_ioctl_version_data *ver, const void *data)
197 {
198 if (ver->impl_id == TEE_IMPL_ID_OPTEE &&
199 ver->gen_caps & TEE_GEN_CAP_REG_MEM)
200 return 1;
201 else
202 return 0;
203 }
204
205 static int trusted_key_probe(struct device *dev)
206 {
207 struct tee_client_device *rng_device = to_tee_client_device(dev);
208 int ret;
209 struct tee_ioctl_open_session_arg sess_arg;
210
211 memset(&sess_arg, 0, sizeof(sess_arg));
212
213 pvt_data.ctx = tee_client_open_context(NULL, optee_ctx_match, NULL,
214 NULL);
215 if (IS_ERR(pvt_data.ctx))
216 return -ENODEV;
217
218 memcpy(sess_arg.uuid, rng_device->id.uuid.b, TEE_IOCTL_UUID_LEN);
219 sess_arg.clnt_login = TEE_IOCTL_LOGIN_REE_KERNEL;
220 sess_arg.num_params = 0;
221
222 ret = tee_client_open_session(pvt_data.ctx, &sess_arg, NULL);
223 if ((ret < 0) || (sess_arg.ret != 0)) {
224 dev_err(dev, "tee_client_open_session failed, err: %x\n",
225 sess_arg.ret);
226 ret = -EINVAL;
227 goto out_ctx;
228 }
229 pvt_data.session_id = sess_arg.session;
230
231 ret = register_key_type(&key_type_trusted);
232 if (ret < 0)
233 goto out_sess;
234
235 pvt_data.dev = dev;
236
237 return 0;
238
239 out_sess:
240 tee_client_close_session(pvt_data.ctx, pvt_data.session_id);
241 out_ctx:
242 tee_client_close_context(pvt_data.ctx);
243
244 return ret;
245 }
246
247 static int trusted_key_remove(struct device *dev)
248 {
249 unregister_key_type(&key_type_trusted);
250 tee_client_close_session(pvt_data.ctx, pvt_data.session_id);
251 tee_client_close_context(pvt_data.ctx);
252
253 return 0;
254 }
255
256 static const struct tee_client_device_id trusted_key_id_table[] = {
257 {UUID_INIT(0xf04a0fe7, 0x1f5d, 0x4b9b,
258 0xab, 0xf7, 0x61, 0x9b, 0x85, 0xb4, 0xce, 0x8c)},
259 {}
260 };
261 MODULE_DEVICE_TABLE(tee, trusted_key_id_table);
262
263 static struct tee_client_driver trusted_key_driver = {
264 .id_table = trusted_key_id_table,
265 .driver = {
266 .name = DRIVER_NAME,
267 .bus = &tee_bus_type,
268 .probe = trusted_key_probe,
269 .remove = trusted_key_remove,
270 },
271 };
272
273 static int trusted_tee_init(void)
274 {
275 return driver_register(&trusted_key_driver.driver);
276 }
277
278 static void trusted_tee_exit(void)
279 {
280 driver_unregister(&trusted_key_driver.driver);
281 }
282
283 struct trusted_key_ops trusted_key_tee_ops = {
284 .migratable = 0, /* non-migratable */
285 .init = trusted_tee_init,
286 .seal = trusted_tee_seal,
287 .unseal = trusted_tee_unseal,
288 .get_random = trusted_tee_get_random,
289 .exit = trusted_tee_exit,
290 };
291
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