drivers/char/tpm/tpm.c

   1 /*
   2  * Copyright (C) 2004 IBM Corporation
   3  *
   4  * Authors:
   5  * Leendert van Doorn <leendert@watson.ibm.com>
   6  * Dave Safford <safford@watson.ibm.com>
   7  * Reiner Sailer <sailer@watson.ibm.com>
   8  * Kylene Hall <kjhall@us.ibm.com>
   9  *
  10  * Maintained by: <tpmdd_devel@lists.sourceforge.net>
  11  *
  12  * Device driver for TCG/TCPA TPM (trusted platform module).
  13  * Specifications at www.trustedcomputinggroup.org
  14  *
  15  * This program is free software; you can redistribute it and/or
  16  * modify it under the terms of the GNU General Public License as
  17  * published by the Free Software Foundation, version 2 of the
  18  * License.
  19  *
  20  * Note, the TPM chip is not interrupt driven (only polling)
  21  * and can have very long timeouts (minutes!). Hence the unusual
  22  * calls to msleep.
  23  *
  24  */
  25
  26 #include <linux/sched.h>
  27 #include <linux/poll.h>
  28 #include <linux/spinlock.h>
  29 #include "tpm.h"
  30
  31 enum tpm_const {
  32         TPM_MINOR = 224,        /* officially assigned */
  33         TPM_BUFSIZE = 2048,
  34         TPM_NUM_DEVICES = 256,
  35         TPM_NUM_MASK_ENTRIES = TPM_NUM_DEVICES / (8 * sizeof(int))
  36 };
  37
  38 static LIST_HEAD(tpm_chip_list);
  39 static DEFINE_SPINLOCK(driver_lock);
  40 static int dev_mask[TPM_NUM_MASK_ENTRIES];
  41
  42 static void user_reader_timeout(unsigned long ptr)
  43 {
  44         struct tpm_chip *chip = (struct tpm_chip *) ptr;
  45
  46         down(&chip->buffer_mutex);
  47         atomic_set(&chip->data_pending, 0);
  48         memset(chip->data_buffer, 0, TPM_BUFSIZE);
  49         up(&chip->buffer_mutex);
  50 }
  51
  52 /*
  53  * Internal kernel interface to transmit TPM commands
  54  */
  55 static ssize_t tpm_transmit(struct tpm_chip *chip, const char *buf,
  56                             size_t bufsiz)
  57 {
  58         ssize_t rc;
  59         u32 count;
  60         unsigned long stop;
  61
  62         count = be32_to_cpu(*((__be32 *) (buf + 2)));
  63
  64         if (count == 0)
  65                 return -ENODATA;
  66         if (count > bufsiz) {
  67                 dev_err(chip->dev,
  68                         "invalid count value %x %zx \n", count, bufsiz);
  69                 return -E2BIG;
  70         }
  71
  72         down(&chip->tpm_mutex);
  73
  74         if ((rc = chip->vendor->send(chip, (u8 *) buf, count)) < 0) {
  75                 dev_err(chip->dev,
  76                         "tpm_transmit: tpm_send: error %zd\n", rc);
  77                 goto out;
  78         }
  79
  80         stop = jiffies + 2 * 60 * HZ;
  81         do {
  82                 u8 status = chip->vendor->status(chip);
  83                 if ((status & chip->vendor->req_complete_mask) ==
  84                     chip->vendor->req_complete_val) {
  85                         goto out_recv;
  86                 }
  87
  88                 if ((status == chip->vendor->req_canceled)) {
  89                         dev_err(chip->dev, "Operation Canceled\n");
  90                         rc = -ECANCELED;
  91                         goto out;
  92                 }
  93
  94                 msleep(TPM_TIMEOUT);    /* CHECK */
  95                 rmb();
  96         } while (time_before(jiffies, stop));
  97
  98
  99         chip->vendor->cancel(chip);
 100         dev_err(chip->dev, "Operation Timed out\n");
 101         rc = -ETIME;
 102         goto out;
 103
 104 out_recv:
 105         rc = chip->vendor->recv(chip, (u8 *) buf, bufsiz);
 106         if (rc < 0)
 107                 dev_err(chip->dev,
 108                         "tpm_transmit: tpm_recv: error %zd\n", rc);
 109 out:
 110         up(&chip->tpm_mutex);
 111         return rc;
 112 }
 113
 114 #define TPM_DIGEST_SIZE 20
 115 #define CAP_PCR_RESULT_SIZE 18
 116 static const u8 cap_pcr[] = {
 117         0, 193,                 /* TPM_TAG_RQU_COMMAND */
 118         0, 0, 0, 22,            /* length */
 119         0, 0, 0, 101,           /* TPM_ORD_GetCapability */
 120         0, 0, 0, 5,
 121         0, 0, 0, 4,
 122         0, 0, 1, 1
 123 };
 124
 125 #define READ_PCR_RESULT_SIZE 30
 126 static const u8 pcrread[] = {
 127         0, 193,                 /* TPM_TAG_RQU_COMMAND */
 128         0, 0, 0, 14,            /* length */
 129         0, 0, 0, 21,            /* TPM_ORD_PcrRead */
 130         0, 0, 0, 0              /* PCR index */
 131 };
 132
 133 ssize_t tpm_show_pcrs(struct device *dev, struct device_attribute *attr,
 134                       char *buf)
 135 {
 136         u8 data[READ_PCR_RESULT_SIZE];
 137         ssize_t len;
 138         int i, j, num_pcrs;
 139         __be32 index;
 140         char *str = buf;
 141
 142         struct tpm_chip *chip = dev_get_drvdata(dev);
 143         if (chip == NULL)
 144                 return -ENODEV;
 145
 146         memcpy(data, cap_pcr, sizeof(cap_pcr));
 147         if ((len = tpm_transmit(chip, data, sizeof(data)))
 148             < CAP_PCR_RESULT_SIZE) {
 149                 dev_dbg(chip->dev, "A TPM error (%d) occurred "
 150                                 "attempting to determine the number of PCRS\n",
 151                         be32_to_cpu(*((__be32 *) (data + 6))));
 152                 return 0;
 153         }
 154
 155         num_pcrs = be32_to_cpu(*((__be32 *) (data + 14)));
 156
 157         for (i = 0; i < num_pcrs; i++) {
 158                 memcpy(data, pcrread, sizeof(pcrread));
 159                 index = cpu_to_be32(i);
 160                 memcpy(data + 10, &index, 4);
 161                 if ((len = tpm_transmit(chip, data, sizeof(data)))
 162                     < READ_PCR_RESULT_SIZE){
 163                         dev_dbg(chip->dev, "A TPM error (%d) occurred"
 164                                 " attempting to read PCR %d of %d\n",
 165                                 be32_to_cpu(*((__be32 *) (data + 6))),
 166                                 i, num_pcrs);
 167                         goto out;
 168                 }
 169                 str += sprintf(str, "PCR-%02d: ", i);
 170                 for (j = 0; j < TPM_DIGEST_SIZE; j++)
 171                         str += sprintf(str, "%02X ", *(data + 10 + j));
 172                 str += sprintf(str, "\n");
 173         }
 174 out:
 175         return str - buf;
 176 }
 177 EXPORT_SYMBOL_GPL(tpm_show_pcrs);
 178
 179 #define  READ_PUBEK_RESULT_SIZE 314
 180 static const u8 readpubek[] = {
 181         0, 193,                 /* TPM_TAG_RQU_COMMAND */
 182         0, 0, 0, 30,            /* length */
 183         0, 0, 0, 124,           /* TPM_ORD_ReadPubek */
 184 };
 185
 186 ssize_t tpm_show_pubek(struct device *dev, struct device_attribute *attr,
 187                        char *buf)
 188 {
 189         u8 *data;
 190         ssize_t len;
 191         int i, rc;
 192         char *str = buf;
 193
 194         struct tpm_chip *chip = dev_get_drvdata(dev);
 195         if (chip == NULL)
 196                 return -ENODEV;
 197
 198         data = kzalloc(READ_PUBEK_RESULT_SIZE, GFP_KERNEL);
 199         if (!data)
 200                 return -ENOMEM;
 201
 202         memcpy(data, readpubek, sizeof(readpubek));
 203
 204         if ((len = tpm_transmit(chip, data, READ_PUBEK_RESULT_SIZE)) <
 205             READ_PUBEK_RESULT_SIZE) {
 206                 dev_dbg(chip->dev, "A TPM error (%d) occurred "
 207                                 "attempting to read the PUBEK\n",
 208                             be32_to_cpu(*((__be32 *) (data + 6))));
 209                 rc = 0;
 210                 goto out;
 211         }
 212
 213         /*
 214            ignore header 10 bytes
 215            algorithm 32 bits (1 == RSA )
 216            encscheme 16 bits
 217            sigscheme 16 bits
 218            parameters (RSA 12->bytes: keybit, #primes, expbit)
 219            keylenbytes 32 bits
 220            256 byte modulus
 221            ignore checksum 20 bytes
 222          */
 223
 224         str +=
 225             sprintf(str,
 226                     "Algorithm: %02X %02X %02X %02X\nEncscheme: %02X %02X\n"
 227                     "Sigscheme: %02X %02X\nParameters: %02X %02X %02X %02X"
 228                     " %02X %02X %02X %02X %02X %02X %02X %02X\n"
 229                     "Modulus length: %d\nModulus: \n",
 230                     data[10], data[11], data[12], data[13], data[14],
 231                     data[15], data[16], data[17], data[22], data[23],
 232                     data[24], data[25], data[26], data[27], data[28],
 233                     data[29], data[30], data[31], data[32], data[33],
 234                     be32_to_cpu(*((__be32 *) (data + 34))));
 235
 236         for (i = 0; i < 256; i++) {
 237                 str += sprintf(str, "%02X ", data[i + 38]);
 238                 if ((i + 1) % 16 == 0)
 239                         str += sprintf(str, "\n");
 240         }
 241         rc = str - buf;
 242 out:
 243         kfree(data);
 244         return rc;
 245 }
 246 EXPORT_SYMBOL_GPL(tpm_show_pubek);
 247
 248 #define CAP_VER_RESULT_SIZE 18
 249 static const u8 cap_version[] = {
 250         0, 193,                 /* TPM_TAG_RQU_COMMAND */
 251         0, 0, 0, 18,            /* length */
 252         0, 0, 0, 101,           /* TPM_ORD_GetCapability */
 253         0, 0, 0, 6,
 254         0, 0, 0, 0
 255 };
 256
 257 #define CAP_MANUFACTURER_RESULT_SIZE 18
 258 static const u8 cap_manufacturer[] = {
 259         0, 193,                 /* TPM_TAG_RQU_COMMAND */
 260         0, 0, 0, 22,            /* length */
 261         0, 0, 0, 101,           /* TPM_ORD_GetCapability */
 262         0, 0, 0, 5,
 263         0, 0, 0, 4,
 264         0, 0, 1, 3
 265 };
 266
 267 ssize_t tpm_show_caps(struct device *dev, struct device_attribute *attr,
 268                       char *buf)
 269 {
 270         u8 data[sizeof(cap_manufacturer)];
 271         ssize_t len;
 272         char *str = buf;
 273
 274         struct tpm_chip *chip = dev_get_drvdata(dev);
 275         if (chip == NULL)
 276                 return -ENODEV;
 277
 278         memcpy(data, cap_manufacturer, sizeof(cap_manufacturer));
 279
 280         if ((len = tpm_transmit(chip, data, sizeof(data))) <
 281             CAP_MANUFACTURER_RESULT_SIZE)
 282                 return len;
 283
 284         str += sprintf(str, "Manufacturer: 0x%x\n",
 285                        be32_to_cpu(*((__be32 *) (data + 14))));
 286
 287         memcpy(data, cap_version, sizeof(cap_version));
 288
 289         if ((len = tpm_transmit(chip, data, sizeof(data))) <
 290             CAP_VER_RESULT_SIZE)
 291                 return len;
 292
 293         str +=
 294             sprintf(str, "TCG version: %d.%d\nFirmware version: %d.%d\n",
 295                     (int) data[14], (int) data[15], (int) data[16],
 296                     (int) data[17]);
 297
 298         return str - buf;
 299 }
 300 EXPORT_SYMBOL_GPL(tpm_show_caps);
 301
 302 ssize_t tpm_store_cancel(struct device *dev, struct device_attribute *attr,
 303                         const char *buf, size_t count)
 304 {
 305         struct tpm_chip *chip = dev_get_drvdata(dev);
 306         if (chip == NULL)
 307                 return 0;
 308
 309         chip->vendor->cancel(chip);
 310         return count;
 311 }
 312 EXPORT_SYMBOL_GPL(tpm_store_cancel);
 313
 314 /*
 315  * Device file system interface to the TPM
 316  */
 317 int tpm_open(struct inode *inode, struct file *file)
 318 {
 319         int rc = 0, minor = iminor(inode);
 320         struct tpm_chip *chip = NULL, *pos;
 321
 322         spin_lock(&driver_lock);
 323
 324         list_for_each_entry(pos, &tpm_chip_list, list) {
 325                 if (pos->vendor->miscdev.minor == minor) {
 326                         chip = pos;
 327                         break;
 328                 }
 329         }
 330
 331         if (chip == NULL) {
 332                 rc = -ENODEV;
 333                 goto err_out;
 334         }
 335
 336         if (chip->num_opens) {
 337                 dev_dbg(chip->dev, "Another process owns this TPM\n");
 338                 rc = -EBUSY;
 339                 goto err_out;
 340         }
 341
 342         chip->num_opens++;
 343         get_device(chip->dev);
 344
 345         spin_unlock(&driver_lock);
 346
 347         chip->data_buffer = kmalloc(TPM_BUFSIZE * sizeof(u8), GFP_KERNEL);
 348         if (chip->data_buffer == NULL) {
 349                 chip->num_opens--;
 350                 put_device(chip->dev);
 351                 return -ENOMEM;
 352         }
 353
 354         atomic_set(&chip->data_pending, 0);
 355
 356         file->private_data = chip;
 357         return 0;
 358
 359 err_out:
 360         spin_unlock(&driver_lock);
 361         return rc;
 362 }
 363 EXPORT_SYMBOL_GPL(tpm_open);
 364
 365 int tpm_release(struct inode *inode, struct file *file)
 366 {
 367         struct tpm_chip *chip = file->private_data;
 368
 369         spin_lock(&driver_lock);
 370         file->private_data = NULL;
 371         chip->num_opens--;
 372         del_singleshot_timer_sync(&chip->user_read_timer);
 373         atomic_set(&chip->data_pending, 0);
 374         put_device(chip->dev);
 375         kfree(chip->data_buffer);
 376         spin_unlock(&driver_lock);
 377         return 0;
 378 }
 379 EXPORT_SYMBOL_GPL(tpm_release);
 380
 381 ssize_t tpm_write(struct file *file, const char __user *buf,
 382                   size_t size, loff_t * off)
 383 {
 384         struct tpm_chip *chip = file->private_data;
 385         int in_size = size, out_size;
 386
 387         /* cannot perform a write until the read has cleared
 388            either via tpm_read or a user_read_timer timeout */
 389         while (atomic_read(&chip->data_pending) != 0)
 390                 msleep(TPM_TIMEOUT);
 391
 392         down(&chip->buffer_mutex);
 393
 394         if (in_size > TPM_BUFSIZE)
 395                 in_size = TPM_BUFSIZE;
 396
 397         if (copy_from_user
 398             (chip->data_buffer, (void __user *) buf, in_size)) {
 399                 up(&chip->buffer_mutex);
 400                 return -EFAULT;
 401         }
 402
 403         /* atomic tpm command send and result receive */
 404         out_size = tpm_transmit(chip, chip->data_buffer, TPM_BUFSIZE);
 405
 406         atomic_set(&chip->data_pending, out_size);
 407         up(&chip->buffer_mutex);
 408
 409         /* Set a timeout by which the reader must come claim the result */
 410         mod_timer(&chip->user_read_timer, jiffies + (60 * HZ));
 411
 412         return in_size;
 413 }
 414
 415 EXPORT_SYMBOL_GPL(tpm_write);
 416
 417 ssize_t tpm_read(struct file * file, char __user *buf,
 418                  size_t size, loff_t * off)
 419 {
 420         struct tpm_chip *chip = file->private_data;
 421         int ret_size;
 422
 423         del_singleshot_timer_sync(&chip->user_read_timer);
 424         ret_size = atomic_read(&chip->data_pending);
 425         atomic_set(&chip->data_pending, 0);
 426         if (ret_size > 0) {     /* relay data */
 427                 if (size < ret_size)
 428                         ret_size = size;
 429
 430                 down(&chip->buffer_mutex);
 431                 if (copy_to_user
 432                     ((void __user *) buf, chip->data_buffer, ret_size))
 433                         ret_size = -EFAULT;
 434                 up(&chip->buffer_mutex);
 435         }
 436
 437         return ret_size;
 438 }
 439 EXPORT_SYMBOL_GPL(tpm_read);
 440
 441 void tpm_remove_hardware(struct device *dev)
 442 {
 443         struct tpm_chip *chip = dev_get_drvdata(dev);
 444
 445         if (chip == NULL) {
 446                 dev_err(dev, "No device data found\n");
 447                 return;
 448         }
 449
 450         spin_lock(&driver_lock);
 451
 452         list_del(&chip->list);
 453
 454         spin_unlock(&driver_lock);
 455
 456         dev_set_drvdata(dev, NULL);
 457         misc_deregister(&chip->vendor->miscdev);
 458         kfree(chip->vendor->miscdev.name);
 459
 460         sysfs_remove_group(&dev->kobj, chip->vendor->attr_group);
 461
 462         dev_mask[chip->dev_num / TPM_NUM_MASK_ENTRIES ] &=
 463                 !(1 << (chip->dev_num % TPM_NUM_MASK_ENTRIES));
 464
 465         kfree(chip);
 466
 467         put_device(dev);
 468 }
 469 EXPORT_SYMBOL_GPL(tpm_remove_hardware);
 470
 471 static u8 savestate[] = {
 472         0, 193,                 /* TPM_TAG_RQU_COMMAND */
 473         0, 0, 0, 10,            /* blob length (in bytes) */
 474         0, 0, 0, 152            /* TPM_ORD_SaveState */
 475 };
 476
 477 /*
 478  * We are about to suspend. Save the TPM state
 479  * so that it can be restored.
 480  */
 481 int tpm_pm_suspend(struct device *dev, pm_message_t pm_state)
 482 {
 483         struct tpm_chip *chip = dev_get_drvdata(dev);
 484         if (chip == NULL)
 485                 return -ENODEV;
 486
 487         tpm_transmit(chip, savestate, sizeof(savestate));
 488         return 0;
 489 }
 490 EXPORT_SYMBOL_GPL(tpm_pm_suspend);
 491
 492 /*
 493  * Resume from a power safe. The BIOS already restored
 494  * the TPM state.
 495  */
 496 int tpm_pm_resume(struct device *dev)
 497 {
 498         struct tpm_chip *chip = dev_get_drvdata(dev);
 499
 500         if (chip == NULL)
 501                 return -ENODEV;
 502
 503         return 0;
 504 }
 505 EXPORT_SYMBOL_GPL(tpm_pm_resume);
 506
 507 /*
 508  * Called from tpm_<specific>.c probe function only for devices
 509  * the driver has determined it should claim.  Prior to calling
 510  * this function the specific probe function has called pci_enable_device
 511  * upon errant exit from this function specific probe function should call
 512  * pci_disable_device
 513  */
 514 int tpm_register_hardware(struct device *dev, struct tpm_vendor_specific *entry)
 515 {
 516 #define DEVNAME_SIZE 7
 517
 518         char *devname;
 519         struct tpm_chip *chip;
 520         int i, j;
 521
 522         /* Driver specific per-device data */
 523         chip = kzalloc(sizeof(*chip), GFP_KERNEL);
 524         if (chip == NULL)
 525                 return -ENOMEM;
 526
 527         init_MUTEX(&chip->buffer_mutex);
 528         init_MUTEX(&chip->tpm_mutex);
 529         INIT_LIST_HEAD(&chip->list);
 530
 531         init_timer(&chip->user_read_timer);
 532         chip->user_read_timer.function = user_reader_timeout;
 533         chip->user_read_timer.data = (unsigned long) chip;
 534
 535         chip->vendor = entry;
 536
 537         chip->dev_num = -1;
 538
 539         for (i = 0; i < TPM_NUM_MASK_ENTRIES; i++)
 540                 for (j = 0; j < 8 * sizeof(int); j++)
 541                         if ((dev_mask[i] & (1 << j)) == 0) {
 542                                 chip->dev_num =
 543                                     i * TPM_NUM_MASK_ENTRIES + j;
 544                                 dev_mask[i] |= 1 << j;
 545                                 goto dev_num_search_complete;
 546                         }
 547
 548 dev_num_search_complete:
 549         if (chip->dev_num < 0) {
 550                 dev_err(dev, "No available tpm device numbers\n");
 551                 kfree(chip);
 552                 return -ENODEV;
 553         } else if (chip->dev_num == 0)
 554                 chip->vendor->miscdev.minor = TPM_MINOR;
 555         else
 556                 chip->vendor->miscdev.minor = MISC_DYNAMIC_MINOR;
 557
 558         devname = kmalloc(DEVNAME_SIZE, GFP_KERNEL);
 559         scnprintf(devname, DEVNAME_SIZE, "%s%d", "tpm", chip->dev_num);
 560         chip->vendor->miscdev.name = devname;
 561
 562         chip->vendor->miscdev.dev = dev;
 563         chip->dev = get_device(dev);
 564
 565         if (misc_register(&chip->vendor->miscdev)) {
 566                 dev_err(chip->dev,
 567                         "unable to misc_register %s, minor %d\n",
 568                         chip->vendor->miscdev.name,
 569                         chip->vendor->miscdev.minor);
 570                 put_device(dev);
 571                 kfree(chip);
 572                 dev_mask[i] &= !(1 << j);
 573                 return -ENODEV;
 574         }
 575
 576         spin_lock(&driver_lock);
 577
 578         dev_set_drvdata(dev, chip);
 579
 580         list_add(&chip->list, &tpm_chip_list);
 581
 582         spin_unlock(&driver_lock);
 583
 584         sysfs_create_group(&dev->kobj, chip->vendor->attr_group);
 585
 586         return 0;
 587 }
 588 EXPORT_SYMBOL_GPL(tpm_register_hardware);
 589
 590 MODULE_AUTHOR("Leendert van Doorn (leendert@watson.ibm.com)");
 591 MODULE_DESCRIPTION("TPM Driver");
 592 MODULE_VERSION("2.0");
 593 MODULE_LICENSE("GPL");