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 */
trusted_tee_seal(struct trusted_key_payload * p,char * datablob)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_in = NULL, *reg_shm_out = NULL;
69
70 memset(&inv_arg, 0, sizeof(inv_arg));
71 memset(¶m, 0, sizeof(param));
72
73 reg_shm_in = tee_shm_register_kernel_buf(pvt_data.ctx, p->key,
74 p->key_len);
75 if (IS_ERR(reg_shm_in)) {
76 dev_err(pvt_data.dev, "key shm register failed\n");
77 return PTR_ERR(reg_shm_in);
78 }
79
80 reg_shm_out = tee_shm_register_kernel_buf(pvt_data.ctx, p->blob,
81 sizeof(p->blob));
82 if (IS_ERR(reg_shm_out)) {
83 dev_err(pvt_data.dev, "blob shm register failed\n");
84 ret = PTR_ERR(reg_shm_out);
85 goto out;
86 }
87
88 inv_arg.func = TA_CMD_SEAL;
89 inv_arg.session = pvt_data.session_id;
90 inv_arg.num_params = 4;
91
92 param[0].attr = TEE_IOCTL_PARAM_ATTR_TYPE_MEMREF_INPUT;
93 param[0].u.memref.shm = reg_shm_in;
94 param[0].u.memref.size = p->key_len;
95 param[0].u.memref.shm_offs = 0;
96 param[1].attr = TEE_IOCTL_PARAM_ATTR_TYPE_MEMREF_OUTPUT;
97 param[1].u.memref.shm = reg_shm_out;
98 param[1].u.memref.size = sizeof(p->blob);
99 param[1].u.memref.shm_offs = 0;
100
101 ret = tee_client_invoke_func(pvt_data.ctx, &inv_arg, param);
102 if ((ret < 0) || (inv_arg.ret != 0)) {
103 dev_err(pvt_data.dev, "TA_CMD_SEAL invoke err: %x\n",
104 inv_arg.ret);
105 ret = -EFAULT;
106 } else {
107 p->blob_len = param[1].u.memref.size;
108 }
109
110 out:
111 if (reg_shm_out)
112 tee_shm_free(reg_shm_out);
113 if (reg_shm_in)
114 tee_shm_free(reg_shm_in);
115
116 return ret;
117 }
118
119 /*
120 * Have the TEE unseal(decrypt) the symmetric key
121 */
trusted_tee_unseal(struct trusted_key_payload * p,char * datablob)122 static int trusted_tee_unseal(struct trusted_key_payload *p, char *datablob)
123 {
124 int ret;
125 struct tee_ioctl_invoke_arg inv_arg;
126 struct tee_param param[4];
127 struct tee_shm *reg_shm_in = NULL, *reg_shm_out = NULL;
128
129 memset(&inv_arg, 0, sizeof(inv_arg));
130 memset(¶m, 0, sizeof(param));
131
132 reg_shm_in = tee_shm_register_kernel_buf(pvt_data.ctx, p->blob,
133 p->blob_len);
134 if (IS_ERR(reg_shm_in)) {
135 dev_err(pvt_data.dev, "blob shm register failed\n");
136 return PTR_ERR(reg_shm_in);
137 }
138
139 reg_shm_out = tee_shm_register_kernel_buf(pvt_data.ctx, p->key,
140 sizeof(p->key));
141 if (IS_ERR(reg_shm_out)) {
142 dev_err(pvt_data.dev, "key shm register failed\n");
143 ret = PTR_ERR(reg_shm_out);
144 goto out;
145 }
146
147 inv_arg.func = TA_CMD_UNSEAL;
148 inv_arg.session = pvt_data.session_id;
149 inv_arg.num_params = 4;
150
151 param[0].attr = TEE_IOCTL_PARAM_ATTR_TYPE_MEMREF_INPUT;
152 param[0].u.memref.shm = reg_shm_in;
153 param[0].u.memref.size = p->blob_len;
154 param[0].u.memref.shm_offs = 0;
155 param[1].attr = TEE_IOCTL_PARAM_ATTR_TYPE_MEMREF_OUTPUT;
156 param[1].u.memref.shm = reg_shm_out;
157 param[1].u.memref.size = sizeof(p->key);
158 param[1].u.memref.shm_offs = 0;
159
160 ret = tee_client_invoke_func(pvt_data.ctx, &inv_arg, param);
161 if ((ret < 0) || (inv_arg.ret != 0)) {
162 dev_err(pvt_data.dev, "TA_CMD_UNSEAL invoke err: %x\n",
163 inv_arg.ret);
164 ret = -EFAULT;
165 } else {
166 p->key_len = param[1].u.memref.size;
167 }
168
169 out:
170 if (reg_shm_out)
171 tee_shm_free(reg_shm_out);
172 if (reg_shm_in)
173 tee_shm_free(reg_shm_in);
174
175 return ret;
176 }
177
178 /*
179 * Have the TEE generate random symmetric key
180 */
trusted_tee_get_random(unsigned char * key,size_t key_len)181 static int trusted_tee_get_random(unsigned char *key, size_t key_len)
182 {
183 int ret;
184 struct tee_ioctl_invoke_arg inv_arg;
185 struct tee_param param[4];
186 struct tee_shm *reg_shm = NULL;
187
188 memset(&inv_arg, 0, sizeof(inv_arg));
189 memset(¶m, 0, sizeof(param));
190
191 reg_shm = tee_shm_register_kernel_buf(pvt_data.ctx, key, key_len);
192 if (IS_ERR(reg_shm)) {
193 dev_err(pvt_data.dev, "key shm register failed\n");
194 return PTR_ERR(reg_shm);
195 }
196
197 inv_arg.func = TA_CMD_GET_RANDOM;
198 inv_arg.session = pvt_data.session_id;
199 inv_arg.num_params = 4;
200
201 param[0].attr = TEE_IOCTL_PARAM_ATTR_TYPE_MEMREF_OUTPUT;
202 param[0].u.memref.shm = reg_shm;
203 param[0].u.memref.size = key_len;
204 param[0].u.memref.shm_offs = 0;
205
206 ret = tee_client_invoke_func(pvt_data.ctx, &inv_arg, param);
207 if ((ret < 0) || (inv_arg.ret != 0)) {
208 dev_err(pvt_data.dev, "TA_CMD_GET_RANDOM invoke err: %x\n",
209 inv_arg.ret);
210 ret = -EFAULT;
211 } else {
212 ret = param[0].u.memref.size;
213 }
214
215 tee_shm_free(reg_shm);
216
217 return ret;
218 }
219
optee_ctx_match(struct tee_ioctl_version_data * ver,const void * data)220 static int optee_ctx_match(struct tee_ioctl_version_data *ver, const void *data)
221 {
222 if (ver->impl_id == TEE_IMPL_ID_OPTEE &&
223 ver->gen_caps & TEE_GEN_CAP_REG_MEM)
224 return 1;
225 else
226 return 0;
227 }
228
trusted_key_probe(struct device * dev)229 static int trusted_key_probe(struct device *dev)
230 {
231 struct tee_client_device *rng_device = to_tee_client_device(dev);
232 int ret;
233 struct tee_ioctl_open_session_arg sess_arg;
234
235 memset(&sess_arg, 0, sizeof(sess_arg));
236
237 pvt_data.ctx = tee_client_open_context(NULL, optee_ctx_match, NULL,
238 NULL);
239 if (IS_ERR(pvt_data.ctx))
240 return -ENODEV;
241
242 memcpy(sess_arg.uuid, rng_device->id.uuid.b, TEE_IOCTL_UUID_LEN);
243 sess_arg.clnt_login = TEE_IOCTL_LOGIN_REE_KERNEL;
244 sess_arg.num_params = 0;
245
246 ret = tee_client_open_session(pvt_data.ctx, &sess_arg, NULL);
247 if ((ret < 0) || (sess_arg.ret != 0)) {
248 dev_err(dev, "tee_client_open_session failed, err: %x\n",
249 sess_arg.ret);
250 ret = -EINVAL;
251 goto out_ctx;
252 }
253 pvt_data.session_id = sess_arg.session;
254
255 ret = register_key_type(&key_type_trusted);
256 if (ret < 0)
257 goto out_sess;
258
259 pvt_data.dev = dev;
260
261 return 0;
262
263 out_sess:
264 tee_client_close_session(pvt_data.ctx, pvt_data.session_id);
265 out_ctx:
266 tee_client_close_context(pvt_data.ctx);
267
268 return ret;
269 }
270
trusted_key_remove(struct device * dev)271 static int trusted_key_remove(struct device *dev)
272 {
273 unregister_key_type(&key_type_trusted);
274 tee_client_close_session(pvt_data.ctx, pvt_data.session_id);
275 tee_client_close_context(pvt_data.ctx);
276
277 return 0;
278 }
279
280 static const struct tee_client_device_id trusted_key_id_table[] = {
281 {UUID_INIT(0xf04a0fe7, 0x1f5d, 0x4b9b,
282 0xab, 0xf7, 0x61, 0x9b, 0x85, 0xb4, 0xce, 0x8c)},
283 {}
284 };
285 MODULE_DEVICE_TABLE(tee, trusted_key_id_table);
286
287 static struct tee_client_driver trusted_key_driver = {
288 .id_table = trusted_key_id_table,
289 .driver = {
290 .name = DRIVER_NAME,
291 .bus = &tee_bus_type,
292 .probe = trusted_key_probe,
293 .remove = trusted_key_remove,
294 },
295 };
296
trusted_tee_init(void)297 static int trusted_tee_init(void)
298 {
299 return driver_register(&trusted_key_driver.driver);
300 }
301
trusted_tee_exit(void)302 static void trusted_tee_exit(void)
303 {
304 driver_unregister(&trusted_key_driver.driver);
305 }
306
307 struct trusted_key_ops trusted_key_tee_ops = {
308 .migratable = 0, /* non-migratable */
309 .init = trusted_tee_init,
310 .seal = trusted_tee_seal,
311 .unseal = trusted_tee_unseal,
312 .get_random = trusted_tee_get_random,
313 .exit = trusted_tee_exit,
314 };
315
