aboutsummaryrefslogtreecommitdiff
path: root/drivers/char/tpm/tpm.c
blob: 5c843c9bf8191ecd987968914256a7ac4ec76388 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
/*
 * Copyright (C) 2004 IBM Corporation
 *
 * Authors:
 * Leendert van Doorn <leendert@watson.ibm.com>
 * Dave Safford <safford@watson.ibm.com>
 * Reiner Sailer <sailer@watson.ibm.com>
 * Kylene Hall <kjhall@us.ibm.com>
 *
 * Maintained by: <tpmdd_devel@lists.sourceforge.net>
 *
 * Device driver for TCG/TCPA TPM (trusted platform module).
 * Specifications at www.trustedcomputinggroup.org	 
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License as
 * published by the Free Software Foundation, version 2 of the
 * License.
 * 
 * Note, the TPM chip is not interrupt driven (only polling)
 * and can have very long timeouts (minutes!). Hence the unusual
 * calls to msleep.
 *
 */

#include <linux/sched.h>
#include <linux/poll.h>
#include <linux/spinlock.h>
#include "tpm.h"

enum tpm_const {
	TPM_MINOR = 224,	/* officially assigned */
	TPM_BUFSIZE = 2048,
	TPM_NUM_DEVICES = 256,
	TPM_NUM_MASK_ENTRIES = TPM_NUM_DEVICES / (8 * sizeof(int))
};

static LIST_HEAD(tpm_chip_list);
static DEFINE_SPINLOCK(driver_lock);
static int dev_mask[TPM_NUM_MASK_ENTRIES];

static void user_reader_timeout(unsigned long ptr)
{
	struct tpm_chip *chip = (struct tpm_chip *) ptr;

	down(&chip->buffer_mutex);
	atomic_set(&chip->data_pending, 0);
	memset(chip->data_buffer, 0, TPM_BUFSIZE);
	up(&chip->buffer_mutex);
}

/*
 * Internal kernel interface to transmit TPM commands
 */
static ssize_t tpm_transmit(struct tpm_chip *chip, const char *buf,
			    size_t bufsiz)
{
	ssize_t rc;
	u32 count;
	unsigned long stop;

	count = be32_to_cpu(*((__be32 *) (buf + 2)));

	if (count == 0)
		return -ENODATA;
	if (count > bufsiz) {
		dev_err(&chip->pci_dev->dev,
			"invalid count value %x %zx \n", count, bufsiz);
		return -E2BIG;
	}

	down(&chip->tpm_mutex);

	if ((rc = chip->vendor->send(chip, (u8 *) buf, count)) < 0) {
		dev_err(&chip->pci_dev->dev,
			"tpm_transmit: tpm_send: error %zd\n", rc);
		goto out;
	}

	stop = jiffies + 2 * 60 * HZ;
	do {
		u8 status = inb(chip->vendor->base + 1);
		if ((status & chip->vendor->req_complete_mask) ==
		    chip->vendor->req_complete_val) {
			goto out_recv;
		}

		if ((status == chip->vendor->req_canceled)) {
			dev_err(&chip->pci_dev->dev, "Operation Canceled\n");
			rc = -ECANCELED;
			goto out;
		}

		msleep(TPM_TIMEOUT);	/* CHECK */
		rmb();
	} while (time_before(jiffies, stop));


	chip->vendor->cancel(chip);
	dev_err(&chip->pci_dev->dev, "Operation Timed out\n");
	rc = -ETIME;
	goto out;

out_recv:
	rc = chip->vendor->recv(chip, (u8 *) buf, bufsiz);
	if (rc < 0)
		dev_err(&chip->pci_dev->dev,
			"tpm_transmit: tpm_recv: error %zd\n", rc);
out:
	up(&chip->tpm_mutex);
	return rc;
}

#define TPM_DIGEST_SIZE 20
#define CAP_PCR_RESULT_SIZE 18
static const u8 cap_pcr[] = {
	0, 193,			/* TPM_TAG_RQU_COMMAND */
	0, 0, 0, 22,		/* length */
	0, 0, 0, 101,		/* TPM_ORD_GetCapability */
	0, 0, 0, 5,
	0, 0, 0, 4,
	0, 0, 1, 1
};

#define READ_PCR_RESULT_SIZE 30
static const u8 pcrread[] = {
	0, 193,			/* TPM_TAG_RQU_COMMAND */
	0, 0, 0, 14,		/* length */
	0, 0, 0, 21,		/* TPM_ORD_PcrRead */
	0, 0, 0, 0		/* PCR index */
};

ssize_t tpm_show_pcrs(struct device *dev, struct device_attribute *attr,
		      char *buf)
{
	u8 data[READ_PCR_RESULT_SIZE];
	ssize_t len;
	int i, j, num_pcrs;
	__be32 index;
	char *str = buf;

	struct tpm_chip *chip =
	    pci_get_drvdata(to_pci_dev(dev));
	if (chip == NULL)
		return -ENODEV;

	memcpy(data, cap_pcr, sizeof(cap_pcr));
	if ((len = tpm_transmit(chip, data, sizeof(data)))
	    < CAP_PCR_RESULT_SIZE) {
		dev_dbg(&chip->pci_dev->dev, "A TPM error (%d) occurred "
				"attempting to determine the number of PCRS\n",
			be32_to_cpu(*((__be32 *) (data + 6))));
		return 0;
	}

	num_pcrs = be32_to_cpu(*((__be32 *) (data + 14)));

	for (i = 0; i < num_pcrs; i++) {
		memcpy(data, pcrread, sizeof(pcrread));
		index = cpu_to_be32(i);
		memcpy(data + 10, &index, 4);
		if ((len = tpm_transmit(chip, data, sizeof(data)))
		    < READ_PCR_RESULT_SIZE){
			dev_dbg(&chip->pci_dev->dev, "A TPM error (%d) occurred"
				" attempting to read PCR %d of %d\n",
				be32_to_cpu(*((__be32 *) (data + 6))), i, num_pcrs);
			goto out;
		}
		str += sprintf(str, "PCR-%02d: ", i);
		for (j = 0; j < TPM_DIGEST_SIZE; j++)
			str += sprintf(str, "%02X ", *(data + 10 + j));
		str += sprintf(str, "\n");
	}
out:
	return str - buf;
}
EXPORT_SYMBOL_GPL(tpm_show_pcrs);

#define  READ_PUBEK_RESULT_SIZE 314
static const u8 readpubek[] = {
	0, 193,			/* TPM_TAG_RQU_COMMAND */
	0, 0, 0, 30,		/* length */
	0, 0, 0, 124,		/* TPM_ORD_ReadPubek */
};

ssize_t tpm_show_pubek(struct device *dev, struct device_attribute *attr,
		       char *buf)
{
	u8 *data;
	ssize_t len;
	int i, rc;
	char *str = buf;

	struct tpm_chip *chip =
	    pci_get_drvdata(to_pci_dev(dev));
	if (chip == NULL)
		return -ENODEV;

	data = kmalloc(READ_PUBEK_RESULT_SIZE, GFP_KERNEL);
	if (!data)
		return -ENOMEM;

	memcpy(data, readpubek, sizeof(readpubek));
	memset(data + sizeof(readpubek), 0, 20);	/* zero nonce */

	if ((len = tpm_transmit(chip, data, READ_PUBEK_RESULT_SIZE)) <
	    READ_PUBEK_RESULT_SIZE) {
		dev_dbg(&chip->pci_dev->dev, "A TPM error (%d) occurred "
				"attempting to read the PUBEK\n",
			    be32_to_cpu(*((__be32 *) (data + 6))));
		rc = 0;
		goto out;
	}

	/* 
	   ignore header 10 bytes
	   algorithm 32 bits (1 == RSA )
	   encscheme 16 bits
	   sigscheme 16 bits
	   parameters (RSA 12->bytes: keybit, #primes, expbit)  
	   keylenbytes 32 bits
	   256 byte modulus
	   ignore checksum 20 bytes
	 */

	str +=
	    sprintf(str,
		    "Algorithm: %02X %02X %02X %02X\nEncscheme: %02X %02X\n"
		    "Sigscheme: %02X %02X\nParameters: %02X %02X %02X %02X"
		    " %02X %02X %02X %02X %02X %02X %02X %02X\n"
		    "Modulus length: %d\nModulus: \n",
		    data[10], data[11], data[12], data[13], data[14],
		    data[15], data[16], data[17], data[22], data[23],
		    data[24], data[25], data[26], data[27], data[28],
		    data[29], data[30], data[31], data[32], data[33],
		    be32_to_cpu(*((__be32 *) (data + 32))));

	for (i = 0; i < 256; i++) {
		str += sprintf(str, "%02X ", data[i + 39]);
		if ((i + 1) % 16 == 0)
			str += sprintf(str, "\n");
	}
	rc = str - buf;
out:
	kfree(data);
	return rc;
}

EXPORT_SYMBOL_GPL(tpm_show_pubek);

#define CAP_VER_RESULT_SIZE 18
static const u8 cap_version[] = {
	0, 193,			/* TPM_TAG_RQU_COMMAND */
	0, 0, 0, 18,		/* length */
	0, 0, 0, 101,		/* TPM_ORD_GetCapability */
	0, 0, 0, 6,
	0, 0, 0, 0
};

#define CAP_MANUFACTURER_RESULT_SIZE 18
static const u8 cap_manufacturer[] = {
	0, 193,			/* TPM_TAG_RQU_COMMAND */
	0, 0, 0, 22,		/* length */
	0, 0, 0, 101,		/* TPM_ORD_GetCapability */
	0, 0, 0, 5,
	0, 0, 0, 4,
	0, 0, 1, 3
};

ssize_t tpm_show_caps(struct device *dev, struct device_attribute *attr,
		      char *buf)
{
	u8 data[sizeof(cap_manufacturer)];
	ssize_t len;
	char *str = buf;

	struct tpm_chip *chip =
	    pci_get_drvdata(to_pci_dev(dev));
	if (chip == NULL)
		return -ENODEV;

	memcpy(data, cap_manufacturer, sizeof(cap_manufacturer));

	if ((len = tpm_transmit(chip, data, sizeof(data))) <
	    CAP_MANUFACTURER_RESULT_SIZE)
		return len;

	str += sprintf(str, "Manufacturer: 0x%x\n",
		       be32_to_cpu(*((__be32 *) (data + 14))));

	memcpy(data, cap_version, sizeof(cap_version));

	if ((len = tpm_transmit(chip, data, sizeof(data))) <
	    CAP_VER_RESULT_SIZE)
		return len;

	str +=
	    sprintf(str, "TCG version: %d.%d\nFirmware version: %d.%d\n",
		    (int) data[14], (int) data[15], (int) data[16],
		    (int) data[17]);

	return str - buf;
}
EXPORT_SYMBOL_GPL(tpm_show_caps);

ssize_t tpm_store_cancel(struct device *dev, struct device_attribute *attr,
			const char *buf, size_t count)
{
	struct tpm_chip *chip = dev_get_drvdata(dev);
	if (chip == NULL)
		return 0;

	chip->vendor->cancel(chip);
	return count;
}
EXPORT_SYMBOL_GPL(tpm_store_cancel);


/*
 * Device file system interface to the TPM
 */
int tpm_open(struct inode *inode, struct file *file)
{
	int rc = 0, minor = iminor(inode);
	struct tpm_chip *chip = NULL, *pos;

	spin_lock(&driver_lock);

	list_for_each_entry(pos, &tpm_chip_list, list) {
		if (pos->vendor->miscdev.minor == minor) {
			chip = pos;
			break;
		}
	}

	if (chip == NULL) {
		rc = -ENODEV;
		goto err_out;
	}

	if (chip->num_opens) {
		dev_dbg(&chip->pci_dev->dev,
			"Another process owns this TPM\n");
		rc = -EBUSY;
		goto err_out;
	}

	chip->num_opens++;
	pci_dev_get(chip->pci_dev);

	spin_unlock(&driver_lock);

	chip->data_buffer = kmalloc(TPM_BUFSIZE * sizeof(u8), GFP_KERNEL);
	if (chip->data_buffer == NULL) {
		chip->num_opens--;
		pci_dev_put(chip->pci_dev);
		return -ENOMEM;
	}

	atomic_set(&chip->data_pending, 0);

	file->private_data = chip;
	return 0;

err_out:
	spin_unlock(&driver_lock);
	return rc;
}

EXPORT_SYMBOL_GPL(tpm_open);

int tpm_release(struct inode *inode, struct file *file)
{
	struct tpm_chip *chip = file->private_data;

	spin_lock(&driver_lock);
	file->private_data = NULL;
	chip->num_opens--;
	del_singleshot_timer_sync(&chip->user_read_timer);
	atomic_set(&chip->data_pending, 0);
	pci_dev_put(chip->pci_dev);
	kfree(chip->data_buffer);
	spin_unlock(&driver_lock);
	return 0;
}

EXPORT_SYMBOL_GPL(tpm_release);

ssize_t tpm_write(struct file * file, const char __user * buf,
		  size_t size, loff_t * off)
{
	struct tpm_chip *chip = file->private_data;
	int in_size = size, out_size;

	/* cannot perform a write until the read has cleared
	   either via tpm_read or a user_read_timer timeout */
	while (atomic_read(&chip->data_pending) != 0)
		msleep(TPM_TIMEOUT);

	down(&chip->buffer_mutex);

	if (in_size > TPM_BUFSIZE)
		in_size = TPM_BUFSIZE;

	if (copy_from_user
	    (chip->data_buffer, (void __user *) buf, in_size)) {
		up(&chip->buffer_mutex);
		return -EFAULT;
	}

	/* atomic tpm command send and result receive */
	out_size = tpm_transmit(chip, chip->data_buffer, TPM_BUFSIZE);

	atomic_set(&chip->data_pending, out_size);
	up(&chip->buffer_mutex);

	/* Set a timeout by which the reader must come claim the result */
	mod_timer(&chip->user_read_timer, jiffies + (60 * HZ));

	return in_size;
}

EXPORT_SYMBOL_GPL(tpm_write);

ssize_t tpm_read(struct file * file, char __user * buf,
		 size_t size, loff_t * off)
{
	struct tpm_chip *chip = file->private_data;
	int ret_size;

	del_singleshot_timer_sync(&chip->user_read_timer);
	ret_size = atomic_read(&chip->data_pending);
	atomic_set(&chip->data_pending, 0);
	if (ret_size > 0) {	/* relay data */
		if (size < ret_size)
			ret_size = size;

		down(&chip->buffer_mutex);
		if (copy_to_user
		    ((void __user *) buf, chip->data_buffer, ret_size))
			ret_size = -EFAULT;
		up(&chip->buffer_mutex);
	}

	return ret_size;
}

EXPORT_SYMBOL_GPL(tpm_read);

void __devexit tpm_remove(struct pci_dev *pci_dev)
{
	struct tpm_chip *chip = pci_get_drvdata(pci_dev);

	if (chip == NULL) {
		dev_err(&pci_dev->dev, "No device data found\n");
		return;
	}

	spin_lock(&driver_lock);

	list_del(&chip->list);

	spin_unlock(&driver_lock);

	pci_set_drvdata(pci_dev, NULL);
	misc_deregister(&chip->vendor->miscdev);

	sysfs_remove_group(&pci_dev->dev.kobj, chip->vendor->attr_group);

	pci_disable_device(pci_dev);

	dev_mask[chip->dev_num / TPM_NUM_MASK_ENTRIES ] &= !(1 << (chip->dev_num % TPM_NUM_MASK_ENTRIES));

	kfree(chip);

	pci_dev_put(pci_dev);
}

EXPORT_SYMBOL_GPL(tpm_remove);

static u8 savestate[] = {
	0, 193,			/* TPM_TAG_RQU_COMMAND */
	0, 0, 0, 10,		/* blob length (in bytes) */
	0, 0, 0, 152		/* TPM_ORD_SaveState */
};

/*
 * We are about to suspend. Save the TPM state
 * so that it can be restored.
 */
int tpm_pm_suspend(struct pci_dev *pci_dev, pm_message_t pm_state)
{
	struct tpm_chip *chip = pci_get_drvdata(pci_dev);
	if (chip == NULL)
		return -ENODEV;

	tpm_transmit(chip, savestate, sizeof(savestate));
	return 0;
}

EXPORT_SYMBOL_GPL(tpm_pm_suspend);

/*
 * Resume from a power safe. The BIOS already restored
 * the TPM state.
 */
int tpm_pm_resume(struct pci_dev *pci_dev)
{
	struct tpm_chip *chip = pci_get_drvdata(pci_dev);

	if (chip == NULL)
		return -ENODEV;

	return 0;
}

EXPORT_SYMBOL_GPL(tpm_pm_resume);

/*
 * Called from tpm_<specific>.c probe function only for devices 
 * the driver has determined it should claim.  Prior to calling
 * this function the specific probe function has called pci_enable_device
 * upon errant exit from this function specific probe function should call
 * pci_disable_device
 */
int tpm_register_hardware(struct pci_dev *pci_dev,
			  struct tpm_vendor_specific *entry)
{
	char devname[7];
	struct tpm_chip *chip;
	int i, j;

	/* Driver specific per-device data */
	chip = kmalloc(sizeof(*chip), GFP_KERNEL);
	if (chip == NULL)
		return -ENOMEM;

	memset(chip, 0, sizeof(struct tpm_chip));

	init_MUTEX(&chip->buffer_mutex);
	init_MUTEX(&chip->tpm_mutex);
	INIT_LIST_HEAD(&chip->list);

	init_timer(&chip->user_read_timer);
	chip->user_read_timer.function = user_reader_timeout;
	chip->user_read_timer.data = (unsigned long) chip;

	chip->vendor = entry;

	chip->dev_num = -1;

	for (i = 0; i < TPM_NUM_MASK_ENTRIES; i++)
		for (j = 0; j < 8 * sizeof(int); j++)
			if ((dev_mask[i] & (1 << j)) == 0) {
				chip->dev_num =
				    i * TPM_NUM_MASK_ENTRIES + j;
				dev_mask[i] |= 1 << j;
				goto dev_num_search_complete;
			}

dev_num_search_complete:
	if (chip->dev_num < 0) {
		dev_err(&pci_dev->dev,
			"No available tpm device numbers\n");
		kfree(chip);
		return -ENODEV;
	} else if (chip->dev_num == 0)
		chip->vendor->miscdev.minor = TPM_MINOR;
	else
		chip->vendor->miscdev.minor = MISC_DYNAMIC_MINOR;

	snprintf(devname, sizeof(devname), "%s%d", "tpm", chip->dev_num);
	chip->vendor->miscdev.name = devname;

	chip->vendor->miscdev.dev = &(pci_dev->dev);
	chip->pci_dev = pci_dev_get(pci_dev);

	if (misc_register(&chip->vendor->miscdev)) {
		dev_err(&chip->pci_dev->dev,
			"unable to misc_register %s, minor %d\n",
			chip->vendor->miscdev.name,
			chip->vendor->miscdev.minor);
		pci_dev_put(pci_dev);
		kfree(chip);
		dev_mask[i] &= !(1 << j);
		return -ENODEV;
	}

	spin_lock(&driver_lock);

	pci_set_drvdata(pci_dev, chip);

	list_add(&chip->list, &tpm_chip_list);

	spin_unlock(&driver_lock);

	sysfs_create_group(&pci_dev->dev.kobj, chip->vendor->attr_group);

	return 0;
}

EXPORT_SYMBOL_GPL(tpm_register_hardware);

MODULE_AUTHOR("Leendert van Doorn (leendert@watson.ibm.com)");
MODULE_DESCRIPTION("TPM Driver");
MODULE_VERSION("2.0");
MODULE_LICENSE("GPL");