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 buf->length = len;
236 return 0;
237 }
238 EXPORT_SYMBOL_GPL(tpm_transmit_cmd);
239
tpm_get_timeouts(struct tpm_chip * chip)240 int tpm_get_timeouts(struct tpm_chip *chip)
241 {
242 if (chip->flags & TPM_CHIP_FLAG_HAVE_TIMEOUTS)
243 return 0;
244
245 if (chip->flags & TPM_CHIP_FLAG_TPM2)
246 return tpm2_get_timeouts(chip);
247 else
248 return tpm1_get_timeouts(chip);
249 }
250 EXPORT_SYMBOL_GPL(tpm_get_timeouts);
251
252 /**
253 * tpm_is_tpm2 - do we a have a TPM2 chip?
254 * @chip: a &struct tpm_chip instance, %NULL for the default chip
255 *
256 * Return:
257 * 1 if we have a TPM2 chip.
258 * 0 if we don't have a TPM2 chip.
259 * A negative number for system errors (errno).
260 */
tpm_is_tpm2(struct tpm_chip * chip)261 int tpm_is_tpm2(struct tpm_chip *chip)
262 {
263 int rc;
264
265 chip = tpm_find_get_ops(chip);
266 if (!chip)
267 return -ENODEV;
268
269 rc = (chip->flags & TPM_CHIP_FLAG_TPM2) != 0;
270
271 tpm_put_ops(chip);
272
273 return rc;
274 }
275 EXPORT_SYMBOL_GPL(tpm_is_tpm2);
276
277 /**
278 * tpm_pcr_read - read a PCR value from SHA1 bank
279 * @chip: a &struct tpm_chip instance, %NULL for the default chip
280 * @pcr_idx: the PCR to be retrieved
281 * @digest: the PCR bank and buffer current PCR value is written to
282 *
283 * Return: same as with tpm_transmit_cmd()
284 */
tpm_pcr_read(struct tpm_chip * chip,u32 pcr_idx,struct tpm_digest * digest)285 int tpm_pcr_read(struct tpm_chip *chip, u32 pcr_idx,
286 struct tpm_digest *digest)
287 {
288 int rc;
289
290 chip = tpm_find_get_ops(chip);
291 if (!chip)
292 return -ENODEV;
293
294 if (chip->flags & TPM_CHIP_FLAG_TPM2)
295 rc = tpm2_pcr_read(chip, pcr_idx, digest, NULL);
296 else
297 rc = tpm1_pcr_read(chip, pcr_idx, digest->digest);
298
299 tpm_put_ops(chip);
300 return rc;
301 }
302 EXPORT_SYMBOL_GPL(tpm_pcr_read);
303
304 /**
305 * tpm_pcr_extend - extend a PCR value in SHA1 bank.
306 * @chip: a &struct tpm_chip instance, %NULL for the default chip
307 * @pcr_idx: the PCR to be retrieved
308 * @digests: array of tpm_digest structures used to extend PCRs
309 *
310 * Note: callers must pass a digest for every allocated PCR bank, in the same
311 * order of the banks in chip->allocated_banks.
312 *
313 * Return: same as with tpm_transmit_cmd()
314 */
tpm_pcr_extend(struct tpm_chip * chip,u32 pcr_idx,struct tpm_digest * digests)315 int tpm_pcr_extend(struct tpm_chip *chip, u32 pcr_idx,
316 struct tpm_digest *digests)
317 {
318 int rc;
319 int i;
320
321 chip = tpm_find_get_ops(chip);
322 if (!chip)
323 return -ENODEV;
324
325 for (i = 0; i < chip->nr_allocated_banks; i++) {
326 if (digests[i].alg_id != chip->allocated_banks[i].alg_id) {
327 rc = -EINVAL;
328 goto out;
329 }
330 }
331
332 if (chip->flags & TPM_CHIP_FLAG_TPM2) {
333 rc = tpm2_pcr_extend(chip, pcr_idx, digests);
334 goto out;
335 }
336
337 rc = tpm1_pcr_extend(chip, pcr_idx, digests[0].digest,
338 "attempting extend a PCR value");
339
340 out:
341 tpm_put_ops(chip);
342 return rc;
343 }
344 EXPORT_SYMBOL_GPL(tpm_pcr_extend);
345
tpm_auto_startup(struct tpm_chip * chip)346 int tpm_auto_startup(struct tpm_chip *chip)
347 {
348 int rc;
349
350 if (!(chip->ops->flags & TPM_OPS_AUTO_STARTUP))
351 return 0;
352
353 if (chip->flags & TPM_CHIP_FLAG_TPM2)
354 rc = tpm2_auto_startup(chip);
355 else
356 rc = tpm1_auto_startup(chip);
357
358 return rc;
359 }
360
361 /*
362 * We are about to suspend. Save the TPM state
363 * so that it can be restored.
364 */
tpm_pm_suspend(struct device * dev)365 int tpm_pm_suspend(struct device *dev)
366 {
367 struct tpm_chip *chip = dev_get_drvdata(dev);
368 int rc = 0;
369
370 if (!chip)
371 return -ENODEV;
372
373 rc = tpm_try_get_ops(chip);
374 if (rc) {
375 /* Can be safely set out of locks, as no action cannot race: */
376 chip->flags |= TPM_CHIP_FLAG_SUSPENDED;
377 goto out;
378 }
379
380 if (chip->flags & TPM_CHIP_FLAG_ALWAYS_POWERED)
381 goto suspended;
382
383 if ((chip->flags & TPM_CHIP_FLAG_FIRMWARE_POWER_MANAGED) &&
384 !pm_suspend_via_firmware())
385 goto suspended;
386
387 if (chip->flags & TPM_CHIP_FLAG_TPM2) {
388 tpm2_end_auth_session(chip);
389 tpm2_shutdown(chip, TPM2_SU_STATE);
390 goto suspended;
391 }
392
393 rc = tpm1_pm_suspend(chip, tpm_suspend_pcr);
394
395 suspended:
396 chip->flags |= TPM_CHIP_FLAG_SUSPENDED;
397 tpm_put_ops(chip);
398
399 out:
400 if (rc)
401 dev_err(dev, "Ignoring error %d while suspending\n", rc);
402 return 0;
403 }
404 EXPORT_SYMBOL_GPL(tpm_pm_suspend);
405
406 /*
407 * Resume from a power safe. The BIOS already restored
408 * the TPM state.
409 */
tpm_pm_resume(struct device * dev)410 int tpm_pm_resume(struct device *dev)
411 {
412 struct tpm_chip *chip = dev_get_drvdata(dev);
413
414 if (chip == NULL)
415 return -ENODEV;
416
417 chip->flags &= ~TPM_CHIP_FLAG_SUSPENDED;
418
419 /*
420 * Guarantee that SUSPENDED is written last, so that hwrng does not
421 * activate before the chip has been fully resumed.
422 */
423 wmb();
424
425 return 0;
426 }
427 EXPORT_SYMBOL_GPL(tpm_pm_resume);
428
429 /**
430 * tpm_get_random() - get random bytes from the TPM's RNG
431 * @chip: a &struct tpm_chip instance, %NULL for the default chip
432 * @out: destination buffer for the random bytes
433 * @max: the max number of bytes to write to @out
434 *
435 * Return: number of random bytes read or a negative error value.
436 */
tpm_get_random(struct tpm_chip * chip,u8 * out,size_t max)437 int tpm_get_random(struct tpm_chip *chip, u8 *out, size_t max)
438 {
439 int rc;
440
441 if (!out || max > TPM_MAX_RNG_DATA)
442 return -EINVAL;
443
444 chip = tpm_find_get_ops(chip);
445 if (!chip)
446 return -ENODEV;
447
448 /* Give back zero bytes, as TPM chip has not yet fully resumed: */
449 if (chip->flags & TPM_CHIP_FLAG_SUSPENDED) {
450 rc = 0;
451 goto out;
452 }
453
454 if (chip->flags & TPM_CHIP_FLAG_TPM2)
455 rc = tpm2_get_random(chip, out, max);
456 else
457 rc = tpm1_get_random(chip, out, max);
458
459 out:
460 tpm_put_ops(chip);
461 return rc;
462 }
463 EXPORT_SYMBOL_GPL(tpm_get_random);
464
tpm_init(void)465 static int __init tpm_init(void)
466 {
467 int rc;
468
469 rc = class_register(&tpm_class);
470 if (rc) {
471 pr_err("couldn't create tpm class\n");
472 return rc;
473 }
474
475 rc = class_register(&tpmrm_class);
476 if (rc) {
477 pr_err("couldn't create tpmrm class\n");
478 goto out_destroy_tpm_class;
479 }
480
481 rc = alloc_chrdev_region(&tpm_devt, 0, 2*TPM_NUM_DEVICES, "tpm");
482 if (rc < 0) {
483 pr_err("tpm: failed to allocate char dev region\n");
484 goto out_destroy_tpmrm_class;
485 }
486
487 rc = tpm_dev_common_init();
488 if (rc) {
489 pr_err("tpm: failed to allocate char dev region\n");
490 goto out_unreg_chrdev;
491 }
492
493 return 0;
494
495 out_unreg_chrdev:
496 unregister_chrdev_region(tpm_devt, 2 * TPM_NUM_DEVICES);
497 out_destroy_tpmrm_class:
498 class_unregister(&tpmrm_class);
499 out_destroy_tpm_class:
500 class_unregister(&tpm_class);
501
502 return rc;
503 }
504
tpm_exit(void)505 static void __exit tpm_exit(void)
506 {
507 idr_destroy(&dev_nums_idr);
508 class_unregister(&tpm_class);
509 class_unregister(&tpmrm_class);
510 unregister_chrdev_region(tpm_devt, 2*TPM_NUM_DEVICES);
511 tpm_dev_common_exit();
512 }
513
514 subsys_initcall(tpm_init);
515 module_exit(tpm_exit);
516
517 MODULE_AUTHOR("Leendert van Doorn <leendert@watson.ibm.com>");
518 MODULE_DESCRIPTION("TPM Driver");
519 MODULE_VERSION("2.0");
520 MODULE_LICENSE("GPL");
521