1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * Copyright (C) 2004 IBM Corporation
4 * Copyright (C) 2014 Intel Corporation
5 *
6 * Authors:
7 * Leendert van Doorn <leendert@watson.ibm.com>
8 * Dave Safford <safford@watson.ibm.com>
9 * Reiner Sailer <sailer@watson.ibm.com>
10 * Kylene Hall <kjhall@us.ibm.com>
11 *
12 * Maintained by: <tpmdd-devel@lists.sourceforge.net>
13 *
14 * Device driver for TCG/TCPA TPM (trusted platform module).
15 * Specifications at www.trustedcomputinggroup.org
16 *
17 * Note, the TPM chip is not interrupt driven (only polling)
18 * and can have very long timeouts (minutes!). Hence the unusual
19 * calls to msleep.
20 */
21
22 #include <linux/poll.h>
23 #include <linux/slab.h>
24 #include <linux/mutex.h>
25 #include <linux/spinlock.h>
26 #include <linux/suspend.h>
27 #include <linux/freezer.h>
28 #include <linux/tpm_eventlog.h>
29
30 #include "tpm.h"
31
32 /*
33 * Bug workaround - some TPM's don't flush the most
34 * recently changed pcr on suspend, so force the flush
35 * with an extend to the selected _unused_ non-volatile pcr.
36 */
37 static u32 tpm_suspend_pcr;
38 module_param_named(suspend_pcr, tpm_suspend_pcr, uint, 0644);
39 MODULE_PARM_DESC(suspend_pcr,
40 "PCR to use for dummy writes to facilitate flush on suspend.");
41
42 /**
43 * tpm_calc_ordinal_duration() - calculate the maximum command duration
44 * @chip: TPM chip to use.
45 * @ordinal: TPM command ordinal.
46 *
47 * The function returns the maximum amount of time the chip could take
48 * to return the result for a particular ordinal in jiffies.
49 *
50 * Return: A maximal duration time for an ordinal in jiffies.
51 */
tpm_calc_ordinal_duration(struct tpm_chip * chip,u32 ordinal)52 unsigned long tpm_calc_ordinal_duration(struct tpm_chip *chip, u32 ordinal)
53 {
54 if (chip->flags & TPM_CHIP_FLAG_TPM2)
55 return tpm2_calc_ordinal_duration(chip, ordinal);
56 else
57 return tpm1_calc_ordinal_duration(chip, ordinal);
58 }
59 EXPORT_SYMBOL_GPL(tpm_calc_ordinal_duration);
60
tpm_try_transmit(struct tpm_chip * chip,void * buf,size_t bufsiz)61 static ssize_t tpm_try_transmit(struct tpm_chip *chip, void *buf, size_t bufsiz)
62 {
63 struct tpm_header *header = buf;
64 int rc;
65 ssize_t len = 0;
66 u32 count, ordinal;
67 unsigned long stop;
68
69 if (bufsiz < TPM_HEADER_SIZE)
70 return -EINVAL;
71
72 if (bufsiz > TPM_BUFSIZE)
73 bufsiz = TPM_BUFSIZE;
74
75 count = be32_to_cpu(header->length);
76 ordinal = be32_to_cpu(header->ordinal);
77 if (count == 0)
78 return -ENODATA;
79 if (count > bufsiz) {
80 dev_err(&chip->dev,
81 "invalid count value %x %zx\n", count, bufsiz);
82 return -E2BIG;
83 }
84
85 rc = chip->ops->send(chip, buf, count);
86 if (rc < 0) {
87 if (rc != -EPIPE)
88 dev_err(&chip->dev,
89 "%s: send(): error %d\n", __func__, rc);
90 return rc;
91 }
92
93 /* A sanity check. send() should just return zero on success e.g.
94 * not the command length.
95 */
96 if (rc > 0) {
97 dev_warn(&chip->dev,
98 "%s: send(): invalid value %d\n", __func__, rc);
99 rc = 0;
100 }
101
102 if (chip->flags & TPM_CHIP_FLAG_IRQ)
103 goto out_recv;
104
105 stop = jiffies + tpm_calc_ordinal_duration(chip, ordinal);
106 do {
107 u8 status = chip->ops->status(chip);
108 if ((status & chip->ops->req_complete_mask) ==
109 chip->ops->req_complete_val)
110 goto out_recv;
111
112 if (chip->ops->req_canceled(chip, status)) {
113 dev_err(&chip->dev, "Operation Canceled\n");
114 return -ECANCELED;
115 }
116
117 tpm_msleep(TPM_TIMEOUT_POLL);
118 rmb();
119 } while (time_before(jiffies, stop));
120
121 chip->ops->cancel(chip);
122 dev_err(&chip->dev, "Operation Timed out\n");
123 return -ETIME;
124
125 out_recv:
126 len = chip->ops->recv(chip, buf, bufsiz);
127 if (len < 0) {
128 rc = len;
129 dev_err(&chip->dev, "tpm_transmit: tpm_recv: error %d\n", rc);
130 } else if (len < TPM_HEADER_SIZE || len != be32_to_cpu(header->length))
131 rc = -EFAULT;
132
133 return rc ? rc : len;
134 }
135
136 /**
137 * tpm_transmit - Internal kernel interface to transmit TPM commands.
138 * @chip: a TPM chip to use
139 * @buf: a TPM command buffer
140 * @bufsiz: length of the TPM command buffer
141 *
142 * A wrapper around tpm_try_transmit() that handles TPM2_RC_RETRY returns from
143 * the TPM and retransmits the command after a delay up to a maximum wait of
144 * TPM2_DURATION_LONG.
145 *
146 * Note that TPM 1.x never returns TPM2_RC_RETRY so the retry logic is TPM 2.0
147 * only.
148 *
149 * Return:
150 * * The response length - OK
151 * * -errno - A system error
152 */
tpm_transmit(struct tpm_chip * chip,u8 * buf,size_t bufsiz)153 ssize_t tpm_transmit(struct tpm_chip *chip, u8 *buf, size_t bufsiz)
154 {
155 struct tpm_header *header = (struct tpm_header *)buf;
156 /* space for header and handles */
157 u8 save[TPM_HEADER_SIZE + 3*sizeof(u32)];
158 unsigned int delay_msec = TPM2_DURATION_SHORT;
159 u32 rc = 0;
160 ssize_t ret;
161 const size_t save_size = min(sizeof(save), bufsiz);
162 /* the command code is where the return code will be */
163 u32 cc = be32_to_cpu(header->return_code);
164
165 /*
166 * Subtlety here: if we have a space, the handles will be
167 * transformed, so when we restore the header we also have to
168 * restore the handles.
169 */
170 memcpy(save, buf, save_size);
171
172 for (;;) {
173 ret = tpm_try_transmit(chip, buf, bufsiz);
174 if (ret < 0)
175 break;
176 rc = be32_to_cpu(header->return_code);
177 if (rc != TPM2_RC_RETRY && rc != TPM2_RC_TESTING)
178 break;
179 /*
180 * return immediately if self test returns test
181 * still running to shorten boot time.
182 */
183 if (rc == TPM2_RC_TESTING && cc == TPM2_CC_SELF_TEST)
184 break;
185
186 if (delay_msec > TPM2_DURATION_LONG) {
187 if (rc == TPM2_RC_RETRY)
188 dev_err(&chip->dev, "in retry loop\n");
189 else
190 dev_err(&chip->dev,
191 "self test is still running\n");
192 break;
193 }
194 tpm_msleep(delay_msec);
195 delay_msec *= 2;
196 memcpy(buf, save, save_size);
197 }
198 return ret;
199 }
200
201 /**
202 * tpm_transmit_cmd - send a tpm command to the device
203 * @chip: a TPM chip to use
204 * @buf: a TPM command buffer
205 * @min_rsp_body_length: minimum expected length of response body
206 * @desc: command description used in the error message
207 *
208 * Return:
209 * * 0 - OK
210 * * -errno - A system error
211 * * TPM_RC - A TPM error
212 */
tpm_transmit_cmd(struct tpm_chip * chip,struct tpm_buf * buf,size_t min_rsp_body_length,const char * desc)213 ssize_t tpm_transmit_cmd(struct tpm_chip *chip, struct tpm_buf *buf,
214 size_t min_rsp_body_length, const char *desc)
215 {
216 const struct tpm_header *header = (struct tpm_header *)buf->data;
217 int err;
218 ssize_t len;
219
220 len = tpm_transmit(chip, buf->data, PAGE_SIZE);
221 if (len < 0)
222 return len;
223
224 err = be32_to_cpu(header->return_code);
225 if (err != 0 && err != TPM_ERR_DISABLED && err != TPM_ERR_DEACTIVATED
226 && err != TPM2_RC_TESTING && desc)
227 dev_err(&chip->dev, "A TPM error (%d) occurred %s\n", err,
228 desc);
229 if (err)
230 return err;
231
232 if (len < min_rsp_body_length + TPM_HEADER_SIZE)
233 return -EFAULT;
234
235 return 0;
236 }
237 EXPORT_SYMBOL_GPL(tpm_transmit_cmd);
238
tpm_get_timeouts(struct tpm_chip * chip)239 int tpm_get_timeouts(struct tpm_chip *chip)
240 {
241 if (chip->flags & TPM_CHIP_FLAG_HAVE_TIMEOUTS)
242 return 0;
243
244 if (chip->flags & TPM_CHIP_FLAG_TPM2)
245 return tpm2_get_timeouts(chip);
246 else
247 return tpm1_get_timeouts(chip);
248 }
249 EXPORT_SYMBOL_GPL(tpm_get_timeouts);
250
251 /**
252 * tpm_is_tpm2 - do we a have a TPM2 chip?
253 * @chip: a &struct tpm_chip instance, %NULL for the default chip
254 *
255 * Return:
256 * 1 if we have a TPM2 chip.
257 * 0 if we don't have a TPM2 chip.
258 * A negative number for system errors (errno).
259 */
tpm_is_tpm2(struct tpm_chip * chip)260 int tpm_is_tpm2(struct tpm_chip *chip)
261 {
262 int rc;
263
264 chip = tpm_find_get_ops(chip);
265 if (!chip)
266 return -ENODEV;
267
268 rc = (chip->flags & TPM_CHIP_FLAG_TPM2) != 0;
269
270 tpm_put_ops(chip);
271
272 return rc;
273 }
274 EXPORT_SYMBOL_GPL(tpm_is_tpm2);
275
276 /**
277 * tpm_pcr_read - read a PCR value from SHA1 bank
278 * @chip: a &struct tpm_chip instance, %NULL for the default chip
279 * @pcr_idx: the PCR to be retrieved
280 * @digest: the PCR bank and buffer current PCR value is written to
281 *
282 * Return: same as with tpm_transmit_cmd()
283 */
tpm_pcr_read(struct tpm_chip * chip,u32 pcr_idx,struct tpm_digest * digest)284 int tpm_pcr_read(struct tpm_chip *chip, u32 pcr_idx,
285 struct tpm_digest *digest)
286 {
287 int rc;
288
289 chip = tpm_find_get_ops(chip);
290 if (!chip)
291 return -ENODEV;
292
293 if (chip->flags & TPM_CHIP_FLAG_TPM2)
294 rc = tpm2_pcr_read(chip, pcr_idx, digest, NULL);
295 else
296 rc = tpm1_pcr_read(chip, pcr_idx, digest->digest);
297
298 tpm_put_ops(chip);
299 return rc;
300 }
301 EXPORT_SYMBOL_GPL(tpm_pcr_read);
302
303 /**
304 * tpm_pcr_extend - extend a PCR value in SHA1 bank.
305 * @chip: a &struct tpm_chip instance, %NULL for the default chip
306 * @pcr_idx: the PCR to be retrieved
307 * @digests: array of tpm_digest structures used to extend PCRs
308 *
309 * Note: callers must pass a digest for every allocated PCR bank, in the same
310 * order of the banks in chip->allocated_banks.
311 *
312 * Return: same as with tpm_transmit_cmd()
313 */
tpm_pcr_extend(struct tpm_chip * chip,u32 pcr_idx,struct tpm_digest * digests)314 int tpm_pcr_extend(struct tpm_chip *chip, u32 pcr_idx,
315 struct tpm_digest *digests)
316 {
317 int rc;
318 int i;
319
320 chip = tpm_find_get_ops(chip);
321 if (!chip)
322 return -ENODEV;
323
324 for (i = 0; i < chip->nr_allocated_banks; i++) {
325 if (digests[i].alg_id != chip->allocated_banks[i].alg_id) {
326 rc = -EINVAL;
327 goto out;
328 }
329 }
330
331 if (chip->flags & TPM_CHIP_FLAG_TPM2) {
332 rc = tpm2_pcr_extend(chip, pcr_idx, digests);
333 goto out;
334 }
335
336 rc = tpm1_pcr_extend(chip, pcr_idx, digests[0].digest,
337 "attempting extend a PCR value");
338
339 out:
340 tpm_put_ops(chip);
341 return rc;
342 }
343 EXPORT_SYMBOL_GPL(tpm_pcr_extend);
344
345 /**
346 * tpm_send - send a TPM command
347 * @chip: a &struct tpm_chip instance, %NULL for the default chip
348 * @cmd: a TPM command buffer
349 * @buflen: the length of the TPM command buffer
350 *
351 * Return: same as with tpm_transmit_cmd()
352 */
tpm_send(struct tpm_chip * chip,void * cmd,size_t buflen)353 int tpm_send(struct tpm_chip *chip, void *cmd, size_t buflen)
354 {
355 struct tpm_buf buf;
356 int rc;
357
358 chip = tpm_find_get_ops(chip);
359 if (!chip)
360 return -ENODEV;
361
362 buf.data = cmd;
363 rc = tpm_transmit_cmd(chip, &buf, 0, "attempting to a send a command");
364
365 tpm_put_ops(chip);
366 return rc;
367 }
368 EXPORT_SYMBOL_GPL(tpm_send);
369
tpm_auto_startup(struct tpm_chip * chip)370 int tpm_auto_startup(struct tpm_chip *chip)
371 {
372 int rc;
373
374 if (!(chip->ops->flags & TPM_OPS_AUTO_STARTUP))
375 return 0;
376
377 if (chip->flags & TPM_CHIP_FLAG_TPM2)
378 rc = tpm2_auto_startup(chip);
379 else
380 rc = tpm1_auto_startup(chip);
381
382 return rc;
383 }
384
385 /*
386 * We are about to suspend. Save the TPM state
387 * so that it can be restored.
388 */
tpm_pm_suspend(struct device * dev)389 int tpm_pm_suspend(struct device *dev)
390 {
391 struct tpm_chip *chip = dev_get_drvdata(dev);
392 int rc = 0;
393
394 if (!chip)
395 return -ENODEV;
396
397 if (chip->flags & TPM_CHIP_FLAG_ALWAYS_POWERED)
398 goto suspended;
399
400 if ((chip->flags & TPM_CHIP_FLAG_FIRMWARE_POWER_MANAGED) &&
401 !pm_suspend_via_firmware())
402 goto suspended;
403
404 if (!tpm_chip_start(chip)) {
405 if (chip->flags & TPM_CHIP_FLAG_TPM2)
406 tpm2_shutdown(chip, TPM2_SU_STATE);
407 else
408 rc = tpm1_pm_suspend(chip, tpm_suspend_pcr);
409
410 tpm_chip_stop(chip);
411 }
412
413 suspended:
414 return rc;
415 }
416 EXPORT_SYMBOL_GPL(tpm_pm_suspend);
417
418 /*
419 * Resume from a power safe. The BIOS already restored
420 * the TPM state.
421 */
tpm_pm_resume(struct device * dev)422 int tpm_pm_resume(struct device *dev)
423 {
424 struct tpm_chip *chip = dev_get_drvdata(dev);
425
426 if (chip == NULL)
427 return -ENODEV;
428
429 return 0;
430 }
431 EXPORT_SYMBOL_GPL(tpm_pm_resume);
432
433 /**
434 * tpm_get_random() - get random bytes from the TPM's RNG
435 * @chip: a &struct tpm_chip instance, %NULL for the default chip
436 * @out: destination buffer for the random bytes
437 * @max: the max number of bytes to write to @out
438 *
439 * Return: number of random bytes read or a negative error value.
440 */
tpm_get_random(struct tpm_chip * chip,u8 * out,size_t max)441 int tpm_get_random(struct tpm_chip *chip, u8 *out, size_t max)
442 {
443 int rc;
444
445 if (!out || max > TPM_MAX_RNG_DATA)
446 return -EINVAL;
447
448 chip = tpm_find_get_ops(chip);
449 if (!chip)
450 return -ENODEV;
451
452 if (chip->flags & TPM_CHIP_FLAG_TPM2)
453 rc = tpm2_get_random(chip, out, max);
454 else
455 rc = tpm1_get_random(chip, out, max);
456
457 tpm_put_ops(chip);
458 return rc;
459 }
460 EXPORT_SYMBOL_GPL(tpm_get_random);
461
tpm_init(void)462 static int __init tpm_init(void)
463 {
464 int rc;
465
466 tpm_class = class_create(THIS_MODULE, "tpm");
467 if (IS_ERR(tpm_class)) {
468 pr_err("couldn't create tpm class\n");
469 return PTR_ERR(tpm_class);
470 }
471
472 tpmrm_class = class_create(THIS_MODULE, "tpmrm");
473 if (IS_ERR(tpmrm_class)) {
474 pr_err("couldn't create tpmrm class\n");
475 rc = PTR_ERR(tpmrm_class);
476 goto out_destroy_tpm_class;
477 }
478
479 rc = alloc_chrdev_region(&tpm_devt, 0, 2*TPM_NUM_DEVICES, "tpm");
480 if (rc < 0) {
481 pr_err("tpm: failed to allocate char dev region\n");
482 goto out_destroy_tpmrm_class;
483 }
484
485 rc = tpm_dev_common_init();
486 if (rc) {
487 pr_err("tpm: failed to allocate char dev region\n");
488 goto out_unreg_chrdev;
489 }
490
491 return 0;
492
493 out_unreg_chrdev:
494 unregister_chrdev_region(tpm_devt, 2 * TPM_NUM_DEVICES);
495 out_destroy_tpmrm_class:
496 class_destroy(tpmrm_class);
497 out_destroy_tpm_class:
498 class_destroy(tpm_class);
499
500 return rc;
501 }
502
tpm_exit(void)503 static void __exit tpm_exit(void)
504 {
505 idr_destroy(&dev_nums_idr);
506 class_destroy(tpm_class);
507 class_destroy(tpmrm_class);
508 unregister_chrdev_region(tpm_devt, 2*TPM_NUM_DEVICES);
509 tpm_dev_common_exit();
510 }
511
512 subsys_initcall(tpm_init);
513 module_exit(tpm_exit);
514
515 MODULE_AUTHOR("Leendert van Doorn (leendert@watson.ibm.com)");
516 MODULE_DESCRIPTION("TPM Driver");
517 MODULE_VERSION("2.0");
518 MODULE_LICENSE("GPL");
519