1 /*-
2 * Copyright (c) 2018 Stormshield.
3 * Copyright (c) 2018 Semihalf.
4 * All rights reserved.
5 *
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions
8 * are met:
9 * 1. Redistributions of source code must retain the above copyright
10 * notice, this list of conditions and the following disclaimer.
11 * 2. Redistributions in binary form must reproduce the above copyright
12 * notice, this list of conditions and the following disclaimer in the
13 * documentation and/or other materials provided with the distribution.
14 *
15 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
16 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
17 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
18 * DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT,
19 * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
20 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
21 * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
22 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
23 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
24 * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
25 * POSSIBILITY OF SUCH DAMAGE.
26 */
27
28 #include <sys/cdefs.h>
29 #include <sys/random.h>
30
31 #include "tpm20.h"
32
33 #define TPM_HARVEST_SIZE 16
34 /*
35 * Perform a harvest every 10 seconds.
36 * Since discrete TPMs are painfully slow
37 * we don't want to execute this too often
38 * as the chip is likely to be used by others too.
39 */
40 #define TPM_HARVEST_INTERVAL 10
41
42 MALLOC_DEFINE(M_TPM20, "tpm_buffer", "buffer for tpm 2.0 driver");
43
44 static void tpm20_discard_buffer(void *arg);
45 #ifdef TPM_HARVEST
46 static void tpm20_harvest(void *arg, int unused);
47 #endif
48 static int tpm20_save_state(device_t dev, bool suspend);
49
50 static d_open_t tpm20_open;
51 static d_close_t tpm20_close;
52 static d_read_t tpm20_read;
53 static d_write_t tpm20_write;
54 static d_ioctl_t tpm20_ioctl;
55
56 static struct cdevsw tpm20_cdevsw = {
57 .d_version = D_VERSION,
58 .d_open = tpm20_open,
59 .d_close = tpm20_close,
60 .d_read = tpm20_read,
61 .d_write = tpm20_write,
62 .d_ioctl = tpm20_ioctl,
63 .d_name = "tpm20",
64 };
65
66 int
tpm20_read(struct cdev * dev,struct uio * uio,int flags)67 tpm20_read(struct cdev *dev, struct uio *uio, int flags)
68 {
69 struct tpm_sc *sc;
70 size_t bytes_to_transfer;
71 size_t offset;
72 int result = 0;
73
74 sc = (struct tpm_sc *)dev->si_drv1;
75
76 callout_stop(&sc->discard_buffer_callout);
77 sx_xlock(&sc->dev_lock);
78 if (sc->owner_tid != uio->uio_td->td_tid) {
79 sx_xunlock(&sc->dev_lock);
80 return (EPERM);
81 }
82
83 bytes_to_transfer = MIN(sc->pending_data_length, uio->uio_resid);
84 offset = sc->total_length - sc->pending_data_length;
85 if (bytes_to_transfer > 0) {
86 result = uiomove((caddr_t) sc->buf + offset, bytes_to_transfer, uio);
87 sc->pending_data_length -= bytes_to_transfer;
88 cv_signal(&sc->buf_cv);
89 } else {
90 result = ETIMEDOUT;
91 }
92
93 sx_xunlock(&sc->dev_lock);
94
95 return (result);
96 }
97
98 int
tpm20_write(struct cdev * dev,struct uio * uio,int flags)99 tpm20_write(struct cdev *dev, struct uio *uio, int flags)
100 {
101 struct tpm_sc *sc;
102 size_t byte_count;
103 int result = 0;
104
105 sc = (struct tpm_sc *)dev->si_drv1;
106
107 byte_count = uio->uio_resid;
108 if (byte_count < TPM_HEADER_SIZE) {
109 device_printf(sc->dev,
110 "Requested transfer is too small\n");
111 return (EINVAL);
112 }
113
114 if (byte_count > TPM_BUFSIZE) {
115 device_printf(sc->dev,
116 "Requested transfer is too large\n");
117 return (E2BIG);
118 }
119
120 sx_xlock(&sc->dev_lock);
121
122 while (sc->pending_data_length != 0)
123 cv_wait(&sc->buf_cv, &sc->dev_lock);
124
125 result = uiomove(sc->buf, byte_count, uio);
126 if (result != 0) {
127 sx_xunlock(&sc->dev_lock);
128 return (result);
129 }
130
131 result = TPM_TRANSMIT(sc->dev, byte_count);
132
133 if (result == 0) {
134 callout_reset(&sc->discard_buffer_callout,
135 TPM_READ_TIMEOUT / tick, tpm20_discard_buffer, sc);
136 sc->owner_tid = uio->uio_td->td_tid;
137 }
138
139 sx_xunlock(&sc->dev_lock);
140 return (result);
141 }
142
143 static void
tpm20_discard_buffer(void * arg)144 tpm20_discard_buffer(void *arg)
145 {
146 struct tpm_sc *sc;
147
148 sc = (struct tpm_sc *)arg;
149 if (callout_pending(&sc->discard_buffer_callout))
150 return;
151
152 sx_xlock(&sc->dev_lock);
153
154 memset(sc->buf, 0, TPM_BUFSIZE);
155 sc->pending_data_length = 0;
156 sc->total_length = 0;
157
158 cv_signal(&sc->buf_cv);
159 sx_xunlock(&sc->dev_lock);
160
161 device_printf(sc->dev,
162 "User failed to read buffer in time\n");
163 }
164
165 int
tpm20_open(struct cdev * dev,int flag,int mode,struct thread * td)166 tpm20_open(struct cdev *dev, int flag, int mode, struct thread *td)
167 {
168
169 return (0);
170 }
171
172 int
tpm20_close(struct cdev * dev,int flag,int mode,struct thread * td)173 tpm20_close(struct cdev *dev, int flag, int mode, struct thread *td)
174 {
175
176 return (0);
177 }
178
179 int
tpm20_ioctl(struct cdev * dev,u_long cmd,caddr_t data,int flags,struct thread * td)180 tpm20_ioctl(struct cdev *dev, u_long cmd, caddr_t data,
181 int flags, struct thread *td)
182 {
183
184 return (ENOTTY);
185 }
186
187 int
tpm20_init(struct tpm_sc * sc)188 tpm20_init(struct tpm_sc *sc)
189 {
190 struct make_dev_args args;
191 int result;
192
193 cv_init(&sc->buf_cv, "TPM buffer cv");
194 callout_init(&sc->discard_buffer_callout, 1);
195 sc->pending_data_length = 0;
196 sc->total_length = 0;
197
198 make_dev_args_init(&args);
199 args.mda_devsw = &tpm20_cdevsw;
200 args.mda_uid = UID_ROOT;
201 args.mda_gid = GID_WHEEL;
202 args.mda_mode = TPM_CDEV_PERM_FLAG;
203 args.mda_si_drv1 = sc;
204 result = make_dev_s(&args, &sc->sc_cdev, TPM_CDEV_NAME);
205 if (result != 0)
206 tpm20_release(sc);
207
208 #ifdef TPM_HARVEST
209 TIMEOUT_TASK_INIT(taskqueue_thread, &sc->harvest_task, 0,
210 tpm20_harvest, sc);
211 taskqueue_enqueue_timeout(taskqueue_thread, &sc->harvest_task, 0);
212 #endif
213
214 return (result);
215
216 }
217
218 void
tpm20_release(struct tpm_sc * sc)219 tpm20_release(struct tpm_sc *sc)
220 {
221
222 #ifdef TPM_HARVEST
223 if (device_is_attached(sc->dev))
224 taskqueue_drain_timeout(taskqueue_thread, &sc->harvest_task);
225 #endif
226
227 if (sc->buf != NULL)
228 free(sc->buf, M_TPM20);
229
230 sx_destroy(&sc->dev_lock);
231 cv_destroy(&sc->buf_cv);
232 if (sc->sc_cdev != NULL)
233 destroy_dev(sc->sc_cdev);
234 }
235
236 int
tpm20_suspend(device_t dev)237 tpm20_suspend(device_t dev)
238 {
239 return (tpm20_save_state(dev, true));
240 }
241
242 int
tpm20_shutdown(device_t dev)243 tpm20_shutdown(device_t dev)
244 {
245 return (tpm20_save_state(dev, false));
246 }
247
248 #ifdef TPM_HARVEST
249 /*
250 * Get TPM_HARVEST_SIZE random bytes and add them
251 * into system entropy pool.
252 */
253 static void
tpm20_harvest(void * arg,int unused)254 tpm20_harvest(void *arg, int unused)
255 {
256 struct tpm_sc *sc;
257 unsigned char entropy[TPM_HARVEST_SIZE];
258 uint16_t entropy_size;
259 int result;
260 uint8_t cmd[] = {
261 0x80, 0x01, /* TPM_ST_NO_SESSIONS tag*/
262 0x00, 0x00, 0x00, 0x0c, /* cmd length */
263 0x00, 0x00, 0x01, 0x7b, /* cmd TPM_CC_GetRandom */
264 0x00, TPM_HARVEST_SIZE /* number of bytes requested */
265 };
266
267 sc = arg;
268 sx_xlock(&sc->dev_lock);
269 while (sc->pending_data_length != 0)
270 cv_wait(&sc->buf_cv, &sc->dev_lock);
271
272 memcpy(sc->buf, cmd, sizeof(cmd));
273 result = TPM_TRANSMIT(sc->dev, sizeof(cmd));
274 if (result != 0) {
275 sx_xunlock(&sc->dev_lock);
276 return;
277 }
278
279 /* Ignore response size */
280 sc->pending_data_length = 0;
281 sc->total_length = 0;
282
283 /* The number of random bytes we got is placed right after the header */
284 entropy_size = (uint16_t) sc->buf[TPM_HEADER_SIZE + 1];
285 if (entropy_size > 0) {
286 entropy_size = MIN(entropy_size, TPM_HARVEST_SIZE);
287 memcpy(entropy,
288 sc->buf + TPM_HEADER_SIZE + sizeof(uint16_t),
289 entropy_size);
290 }
291
292 sx_xunlock(&sc->dev_lock);
293 if (entropy_size > 0)
294 random_harvest_queue(entropy, entropy_size, RANDOM_PURE_TPM);
295
296 taskqueue_enqueue_timeout(taskqueue_thread, &sc->harvest_task,
297 hz * TPM_HARVEST_INTERVAL);
298 }
299 #endif /* TPM_HARVEST */
300
301 static int
tpm20_save_state(device_t dev,bool suspend)302 tpm20_save_state(device_t dev, bool suspend)
303 {
304 struct tpm_sc *sc;
305 uint8_t save_cmd[] = {
306 0x80, 0x01, /* TPM_ST_NO_SESSIONS tag*/
307 0x00, 0x00, 0x00, 0x0C, /* cmd length */
308 0x00, 0x00, 0x01, 0x45, /* cmd TPM_CC_Shutdown */
309 0x00, 0x00 /* TPM_SU_STATE */
310 };
311
312 sc = device_get_softc(dev);
313
314 /*
315 * Inform the TPM whether we are going to suspend or reboot/shutdown.
316 */
317 if (suspend)
318 save_cmd[11] = 1; /* TPM_SU_STATE */
319
320 if (sc == NULL || sc->buf == NULL)
321 return (0);
322
323 sx_xlock(&sc->dev_lock);
324
325 memcpy(sc->buf, save_cmd, sizeof(save_cmd));
326 TPM_TRANSMIT(sc->dev, sizeof(save_cmd));
327
328 sx_xunlock(&sc->dev_lock);
329
330 return (0);
331 }
332
333 int32_t
tpm20_get_timeout(uint32_t command)334 tpm20_get_timeout(uint32_t command)
335 {
336 int32_t timeout;
337
338 switch (command) {
339 case TPM_CC_CreatePrimary:
340 case TPM_CC_Create:
341 case TPM_CC_CreateLoaded:
342 timeout = TPM_TIMEOUT_LONG;
343 break;
344 case TPM_CC_SequenceComplete:
345 case TPM_CC_Startup:
346 case TPM_CC_SequenceUpdate:
347 case TPM_CC_GetCapability:
348 case TPM_CC_PCR_Extend:
349 case TPM_CC_EventSequenceComplete:
350 case TPM_CC_HashSequenceStart:
351 timeout = TPM_TIMEOUT_C;
352 break;
353 default:
354 timeout = TPM_TIMEOUT_B;
355 break;
356 }
357 return timeout;
358 }
359