root/drivers/char/tpm/tpm-interface.c

DEFINITIONS

1. tpm_calc_ordinal_duration
2. tpm_try_transmit
3. tpm_transmit
4. tpm_transmit_cmd
5. tpm_get_timeouts
6. tpm_is_tpm2
7. tpm_pcr_read
8. tpm_pcr_extend
9. tpm_send
10. tpm_auto_startup
11. tpm_pm_suspend
12. tpm_pm_resume
13. tpm_get_random
14. tpm_seal_trusted
15. tpm_unseal_trusted
16. tpm_init
17. tpm_exit

   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/freezer.h>
  27 #include <linux/tpm_eventlog.h>
  28 
  29 #include "tpm.h"
  30 
  31 /*
  32  * Bug workaround - some TPM's don't flush the most
  33  * recently changed pcr on suspend, so force the flush
  34  * with an extend to the selected _unused_ non-volatile pcr.
  35  */
  36 static u32 tpm_suspend_pcr;
  37 module_param_named(suspend_pcr, tpm_suspend_pcr, uint, 0644);
  38 MODULE_PARM_DESC(suspend_pcr,
  39                  "PCR to use for dummy writes to facilitate flush on suspend.");
  40 
  41 /**
  42  * tpm_calc_ordinal_duration() - calculate the maximum command duration
  43  * @chip:    TPM chip to use.
  44  * @ordinal: TPM command ordinal.
  45  *
  46  * The function returns the maximum amount of time the chip could take
  47  * to return the result for a particular ordinal in jiffies.
  48  *
  49  * Return: A maximal duration time for an ordinal in jiffies.
  50  */
  51 unsigned long tpm_calc_ordinal_duration(struct tpm_chip *chip, u32 ordinal)
  52 {
  53         if (chip->flags & TPM_CHIP_FLAG_TPM2)
  54                 return tpm2_calc_ordinal_duration(chip, ordinal);
  55         else
  56                 return tpm1_calc_ordinal_duration(chip, ordinal);
  57 }
  58 EXPORT_SYMBOL_GPL(tpm_calc_ordinal_duration);
  59 
  60 static ssize_t tpm_try_transmit(struct tpm_chip *chip, void *buf, size_t bufsiz)
  61 {
  62         struct tpm_header *header = buf;
  63         int rc;
  64         ssize_t len = 0;
  65         u32 count, ordinal;
  66         unsigned long stop;
  67 
  68         if (bufsiz < TPM_HEADER_SIZE)
  69                 return -EINVAL;
  70 
  71         if (bufsiz > TPM_BUFSIZE)
  72                 bufsiz = TPM_BUFSIZE;
  73 
  74         count = be32_to_cpu(header->length);
  75         ordinal = be32_to_cpu(header->ordinal);
  76         if (count == 0)
  77                 return -ENODATA;
  78         if (count > bufsiz) {
  79                 dev_err(&chip->dev,
  80                         "invalid count value %x %zx\n", count, bufsiz);
  81                 return -E2BIG;
  82         }
  83 
  84         rc = chip->ops->send(chip, buf, count);
  85         if (rc < 0) {
  86                 if (rc != -EPIPE)
  87                         dev_err(&chip->dev,
  88                                 "%s: send(): error %d\n", __func__, rc);
  89                 return rc;
  90         }
  91 
  92         /* A sanity check. send() should just return zero on success e.g.
  93          * not the command length.
  94          */
  95         if (rc > 0) {
  96                 dev_warn(&chip->dev,
  97                          "%s: send(): invalid value %d\n", __func__, rc);
  98                 rc = 0;
  99         }
 100 
 101         if (chip->flags & TPM_CHIP_FLAG_IRQ)
 102                 goto out_recv;
 103 
 104         stop = jiffies + tpm_calc_ordinal_duration(chip, ordinal);
 105         do {
 106                 u8 status = chip->ops->status(chip);
 107                 if ((status & chip->ops->req_complete_mask) ==
 108                     chip->ops->req_complete_val)
 109                         goto out_recv;
 110 
 111                 if (chip->ops->req_canceled(chip, status)) {
 112                         dev_err(&chip->dev, "Operation Canceled\n");
 113                         return -ECANCELED;
 114                 }
 115 
 116                 tpm_msleep(TPM_TIMEOUT_POLL);
 117                 rmb();
 118         } while (time_before(jiffies, stop));
 119 
 120         chip->ops->cancel(chip);
 121         dev_err(&chip->dev, "Operation Timed out\n");
 122         return -ETIME;
 123 
 124 out_recv:
 125         len = chip->ops->recv(chip, buf, bufsiz);
 126         if (len < 0) {
 127                 rc = len;
 128                 dev_err(&chip->dev, "tpm_transmit: tpm_recv: error %d\n", rc);
 129         } else if (len < TPM_HEADER_SIZE || len != be32_to_cpu(header->length))
 130                 rc = -EFAULT;
 131 
 132         return rc ? rc : len;
 133 }
 134 
 135 /**
 136  * tpm_transmit - Internal kernel interface to transmit TPM commands.
 137  * @chip:       a TPM chip to use
 138  * @buf:        a TPM command buffer
 139  * @bufsiz:     length of the TPM command buffer
 140  *
 141  * A wrapper around tpm_try_transmit() that handles TPM2_RC_RETRY returns from
 142  * the TPM and retransmits the command after a delay up to a maximum wait of
 143  * TPM2_DURATION_LONG.
 144  *
 145  * Note that TPM 1.x never returns TPM2_RC_RETRY so the retry logic is TPM 2.0
 146  * only.
 147  *
 148  * Return:
 149  * * The response length        - OK
 150  * * -errno                     - A system error
 151  */
 152 ssize_t tpm_transmit(struct tpm_chip *chip, u8 *buf, size_t bufsiz)
 153 {
 154         struct tpm_header *header = (struct tpm_header *)buf;
 155         /* space for header and handles */
 156         u8 save[TPM_HEADER_SIZE + 3*sizeof(u32)];
 157         unsigned int delay_msec = TPM2_DURATION_SHORT;
 158         u32 rc = 0;
 159         ssize_t ret;
 160         const size_t save_size = min(sizeof(save), bufsiz);
 161         /* the command code is where the return code will be */
 162         u32 cc = be32_to_cpu(header->return_code);
 163 
 164         /*
 165          * Subtlety here: if we have a space, the handles will be
 166          * transformed, so when we restore the header we also have to
 167          * restore the handles.
 168          */
 169         memcpy(save, buf, save_size);
 170 
 171         for (;;) {
 172                 ret = tpm_try_transmit(chip, buf, bufsiz);
 173                 if (ret < 0)
 174                         break;
 175                 rc = be32_to_cpu(header->return_code);
 176                 if (rc != TPM2_RC_RETRY && rc != TPM2_RC_TESTING)
 177                         break;
 178                 /*
 179                  * return immediately if self test returns test
 180                  * still running to shorten boot time.
 181                  */
 182                 if (rc == TPM2_RC_TESTING && cc == TPM2_CC_SELF_TEST)
 183                         break;
 184 
 185                 if (delay_msec > TPM2_DURATION_LONG) {
 186                         if (rc == TPM2_RC_RETRY)
 187                                 dev_err(&chip->dev, "in retry loop\n");
 188                         else
 189                                 dev_err(&chip->dev,
 190                                         "self test is still running\n");
 191                         break;
 192                 }
 193                 tpm_msleep(delay_msec);
 194                 delay_msec *= 2;
 195                 memcpy(buf, save, save_size);
 196         }
 197         return ret;
 198 }
 199 
 200 /**
 201  * tpm_transmit_cmd - send a tpm command to the device
 202  * @chip:                       a TPM chip to use
 203  * @buf:                        a TPM command buffer
 204  * @min_rsp_body_length:        minimum expected length of response body
 205  * @desc:                       command description used in the error message
 206  *
 207  * Return:
 208  * * 0          - OK
 209  * * -errno     - A system error
 210  * * TPM_RC     - A TPM error
 211  */
 212 ssize_t tpm_transmit_cmd(struct tpm_chip *chip, struct tpm_buf *buf,
 213                          size_t min_rsp_body_length, const char *desc)
 214 {
 215         const struct tpm_header *header = (struct tpm_header *)buf->data;
 216         int err;
 217         ssize_t len;
 218 
 219         len = tpm_transmit(chip, buf->data, PAGE_SIZE);
 220         if (len <  0)
 221                 return len;
 222 
 223         err = be32_to_cpu(header->return_code);
 224         if (err != 0 && err != TPM_ERR_DISABLED && err != TPM_ERR_DEACTIVATED
 225             && err != TPM2_RC_TESTING && desc)
 226                 dev_err(&chip->dev, "A TPM error (%d) occurred %s\n", err,
 227                         desc);
 228         if (err)
 229                 return err;
 230 
 231         if (len < min_rsp_body_length + TPM_HEADER_SIZE)
 232                 return -EFAULT;
 233 
 234         return 0;
 235 }
 236 EXPORT_SYMBOL_GPL(tpm_transmit_cmd);
 237 
 238 int tpm_get_timeouts(struct tpm_chip *chip)
 239 {
 240         if (chip->flags & TPM_CHIP_FLAG_HAVE_TIMEOUTS)
 241                 return 0;
 242 
 243         if (chip->flags & TPM_CHIP_FLAG_TPM2)
 244                 return tpm2_get_timeouts(chip);
 245         else
 246                 return tpm1_get_timeouts(chip);
 247 }
 248 EXPORT_SYMBOL_GPL(tpm_get_timeouts);
 249 
 250 /**
 251  * tpm_is_tpm2 - do we a have a TPM2 chip?
 252  * @chip:       a &struct tpm_chip instance, %NULL for the default chip
 253  *
 254  * Return:
 255  * 1 if we have a TPM2 chip.
 256  * 0 if we don't have a TPM2 chip.
 257  * A negative number for system errors (errno).
 258  */
 259 int tpm_is_tpm2(struct tpm_chip *chip)
 260 {
 261         int rc;
 262 
 263         chip = tpm_find_get_ops(chip);
 264         if (!chip)
 265                 return -ENODEV;
 266 
 267         rc = (chip->flags & TPM_CHIP_FLAG_TPM2) != 0;
 268 
 269         tpm_put_ops(chip);
 270 
 271         return rc;
 272 }
 273 EXPORT_SYMBOL_GPL(tpm_is_tpm2);
 274 
 275 /**
 276  * tpm_pcr_read - read a PCR value from SHA1 bank
 277  * @chip:       a &struct tpm_chip instance, %NULL for the default chip
 278  * @pcr_idx:    the PCR to be retrieved
 279  * @digest:     the PCR bank and buffer current PCR value is written to
 280  *
 281  * Return: same as with tpm_transmit_cmd()
 282  */
 283 int tpm_pcr_read(struct tpm_chip *chip, u32 pcr_idx,
 284                  struct tpm_digest *digest)
 285 {
 286         int rc;
 287 
 288         chip = tpm_find_get_ops(chip);
 289         if (!chip)
 290                 return -ENODEV;
 291 
 292         if (chip->flags & TPM_CHIP_FLAG_TPM2)
 293                 rc = tpm2_pcr_read(chip, pcr_idx, digest, NULL);
 294         else
 295                 rc = tpm1_pcr_read(chip, pcr_idx, digest->digest);
 296 
 297         tpm_put_ops(chip);
 298         return rc;
 299 }
 300 EXPORT_SYMBOL_GPL(tpm_pcr_read);
 301 
 302 /**
 303  * tpm_pcr_extend - extend a PCR value in SHA1 bank.
 304  * @chip:       a &struct tpm_chip instance, %NULL for the default chip
 305  * @pcr_idx:    the PCR to be retrieved
 306  * @digests:    array of tpm_digest structures used to extend PCRs
 307  *
 308  * Note: callers must pass a digest for every allocated PCR bank, in the same
 309  * order of the banks in chip->allocated_banks.
 310  *
 311  * Return: same as with tpm_transmit_cmd()
 312  */
 313 int tpm_pcr_extend(struct tpm_chip *chip, u32 pcr_idx,
 314                    struct tpm_digest *digests)
 315 {
 316         int rc;
 317         int i;
 318 
 319         chip = tpm_find_get_ops(chip);
 320         if (!chip)
 321                 return -ENODEV;
 322 
 323         for (i = 0; i < chip->nr_allocated_banks; i++) {
 324                 if (digests[i].alg_id != chip->allocated_banks[i].alg_id) {
 325                         rc = -EINVAL;
 326                         goto out;
 327                 }
 328         }
 329 
 330         if (chip->flags & TPM_CHIP_FLAG_TPM2) {
 331                 rc = tpm2_pcr_extend(chip, pcr_idx, digests);
 332                 goto out;
 333         }
 334 
 335         rc = tpm1_pcr_extend(chip, pcr_idx, digests[0].digest,
 336                              "attempting extend a PCR value");
 337 
 338 out:
 339         tpm_put_ops(chip);
 340         return rc;
 341 }
 342 EXPORT_SYMBOL_GPL(tpm_pcr_extend);
 343 
 344 /**
 345  * tpm_send - send a TPM command
 346  * @chip:       a &struct tpm_chip instance, %NULL for the default chip
 347  * @cmd:        a TPM command buffer
 348  * @buflen:     the length of the TPM command buffer
 349  *
 350  * Return: same as with tpm_transmit_cmd()
 351  */
 352 int tpm_send(struct tpm_chip *chip, void *cmd, size_t buflen)
 353 {
 354         struct tpm_buf buf;
 355         int rc;
 356 
 357         chip = tpm_find_get_ops(chip);
 358         if (!chip)
 359                 return -ENODEV;
 360 
 361         buf.data = cmd;
 362         rc = tpm_transmit_cmd(chip, &buf, 0, "attempting to a send a command");
 363 
 364         tpm_put_ops(chip);
 365         return rc;
 366 }
 367 EXPORT_SYMBOL_GPL(tpm_send);
 368 
 369 int tpm_auto_startup(struct tpm_chip *chip)
 370 {
 371         int rc;
 372 
 373         if (!(chip->ops->flags & TPM_OPS_AUTO_STARTUP))
 374                 return 0;
 375 
 376         if (chip->flags & TPM_CHIP_FLAG_TPM2)
 377                 rc = tpm2_auto_startup(chip);
 378         else
 379                 rc = tpm1_auto_startup(chip);
 380 
 381         return rc;
 382 }
 383 
 384 /*
 385  * We are about to suspend. Save the TPM state
 386  * so that it can be restored.
 387  */
 388 int tpm_pm_suspend(struct device *dev)
 389 {
 390         struct tpm_chip *chip = dev_get_drvdata(dev);
 391         int rc = 0;
 392 
 393         if (!chip)
 394                 return -ENODEV;
 395 
 396         if (chip->flags & TPM_CHIP_FLAG_ALWAYS_POWERED)
 397                 return 0;
 398 
 399         if (!tpm_chip_start(chip)) {
 400                 if (chip->flags & TPM_CHIP_FLAG_TPM2)
 401                         tpm2_shutdown(chip, TPM2_SU_STATE);
 402                 else
 403                         rc = tpm1_pm_suspend(chip, tpm_suspend_pcr);
 404 
 405                 tpm_chip_stop(chip);
 406         }
 407 
 408         return rc;
 409 }
 410 EXPORT_SYMBOL_GPL(tpm_pm_suspend);
 411 
 412 /*
 413  * Resume from a power safe. The BIOS already restored
 414  * the TPM state.
 415  */
 416 int tpm_pm_resume(struct device *dev)
 417 {
 418         struct tpm_chip *chip = dev_get_drvdata(dev);
 419 
 420         if (chip == NULL)
 421                 return -ENODEV;
 422 
 423         return 0;
 424 }
 425 EXPORT_SYMBOL_GPL(tpm_pm_resume);
 426 
 427 /**
 428  * tpm_get_random() - get random bytes from the TPM's RNG
 429  * @chip:       a &struct tpm_chip instance, %NULL for the default chip
 430  * @out:        destination buffer for the random bytes
 431  * @max:        the max number of bytes to write to @out
 432  *
 433  * Return: number of random bytes read or a negative error value.
 434  */
 435 int tpm_get_random(struct tpm_chip *chip, u8 *out, size_t max)
 436 {
 437         int rc;
 438 
 439         if (!out || max > TPM_MAX_RNG_DATA)
 440                 return -EINVAL;
 441 
 442         chip = tpm_find_get_ops(chip);
 443         if (!chip)
 444                 return -ENODEV;
 445 
 446         if (chip->flags & TPM_CHIP_FLAG_TPM2)
 447                 rc = tpm2_get_random(chip, out, max);
 448         else
 449                 rc = tpm1_get_random(chip, out, max);
 450 
 451         tpm_put_ops(chip);
 452         return rc;
 453 }
 454 EXPORT_SYMBOL_GPL(tpm_get_random);
 455 
 456 /**
 457  * tpm_seal_trusted() - seal a trusted key payload
 458  * @chip:       a &struct tpm_chip instance, %NULL for the default chip
 459  * @options:    authentication values and other options
 460  * @payload:    the key data in clear and encrypted form
 461  *
 462  * Note: only TPM 2.0 chip are supported. TPM 1.x implementation is located in
 463  * the keyring subsystem.
 464  *
 465  * Return: same as with tpm_transmit_cmd()
 466  */
 467 int tpm_seal_trusted(struct tpm_chip *chip, struct trusted_key_payload *payload,
 468                      struct trusted_key_options *options)
 469 {
 470         int rc;
 471 
 472         chip = tpm_find_get_ops(chip);
 473         if (!chip || !(chip->flags & TPM_CHIP_FLAG_TPM2))
 474                 return -ENODEV;
 475 
 476         rc = tpm2_seal_trusted(chip, payload, options);
 477 
 478         tpm_put_ops(chip);
 479         return rc;
 480 }
 481 EXPORT_SYMBOL_GPL(tpm_seal_trusted);
 482 
 483 /**
 484  * tpm_unseal_trusted() - unseal a trusted key
 485  * @chip:       a &struct tpm_chip instance, %NULL for the default chip
 486  * @options:    authentication values and other options
 487  * @payload:    the key data in clear and encrypted form
 488  *
 489  * Note: only TPM 2.0 chip are supported. TPM 1.x implementation is located in
 490  * the keyring subsystem.
 491  *
 492  * Return: same as with tpm_transmit_cmd()
 493  */
 494 int tpm_unseal_trusted(struct tpm_chip *chip,
 495                        struct trusted_key_payload *payload,
 496                        struct trusted_key_options *options)
 497 {
 498         int rc;
 499 
 500         chip = tpm_find_get_ops(chip);
 501         if (!chip || !(chip->flags & TPM_CHIP_FLAG_TPM2))
 502                 return -ENODEV;
 503 
 504         rc = tpm2_unseal_trusted(chip, payload, options);
 505 
 506         tpm_put_ops(chip);
 507 
 508         return rc;
 509 }
 510 EXPORT_SYMBOL_GPL(tpm_unseal_trusted);
 511 
 512 static int __init tpm_init(void)
 513 {
 514         int rc;
 515 
 516         tpm_class = class_create(THIS_MODULE, "tpm");
 517         if (IS_ERR(tpm_class)) {
 518                 pr_err("couldn't create tpm class\n");
 519                 return PTR_ERR(tpm_class);
 520         }
 521 
 522         tpmrm_class = class_create(THIS_MODULE, "tpmrm");
 523         if (IS_ERR(tpmrm_class)) {
 524                 pr_err("couldn't create tpmrm class\n");
 525                 rc = PTR_ERR(tpmrm_class);
 526                 goto out_destroy_tpm_class;
 527         }
 528 
 529         rc = alloc_chrdev_region(&tpm_devt, 0, 2*TPM_NUM_DEVICES, "tpm");
 530         if (rc < 0) {
 531                 pr_err("tpm: failed to allocate char dev region\n");
 532                 goto out_destroy_tpmrm_class;
 533         }
 534 
 535         rc = tpm_dev_common_init();
 536         if (rc) {
 537                 pr_err("tpm: failed to allocate char dev region\n");
 538                 goto out_unreg_chrdev;
 539         }
 540 
 541         return 0;
 542 
 543 out_unreg_chrdev:
 544         unregister_chrdev_region(tpm_devt, 2 * TPM_NUM_DEVICES);
 545 out_destroy_tpmrm_class:
 546         class_destroy(tpmrm_class);
 547 out_destroy_tpm_class:
 548         class_destroy(tpm_class);
 549 
 550         return rc;
 551 }
 552 
 553 static void __exit tpm_exit(void)
 554 {
 555         idr_destroy(&dev_nums_idr);
 556         class_destroy(tpm_class);
 557         class_destroy(tpmrm_class);
 558         unregister_chrdev_region(tpm_devt, 2*TPM_NUM_DEVICES);
 559         tpm_dev_common_exit();
 560 }
 561 
 562 subsys_initcall(tpm_init);
 563 module_exit(tpm_exit);
 564 
 565 MODULE_AUTHOR("Leendert van Doorn (leendert@watson.ibm.com)");
 566 MODULE_DESCRIPTION("TPM Driver");
 567 MODULE_VERSION("2.0");
 568 MODULE_LICENSE("GPL");