xref: /openbmc/linux/drivers/char/tpm/tpm-sysfs.c (revision aac28965)
1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * Copyright (C) 2004 IBM Corporation
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  * Copyright (C) 2013 Obsidian Research Corp
11  * Jason Gunthorpe <jgunthorpe@obsidianresearch.com>
12  *
13  * sysfs filesystem inspection interface to the TPM
14  */
15 #include <linux/device.h>
16 #include "tpm.h"
17 
18 struct tpm_readpubek_out {
19 	u8 algorithm[4];
20 	u8 encscheme[2];
21 	u8 sigscheme[2];
22 	__be32 paramsize;
23 	u8 parameters[12];
24 	__be32 keysize;
25 	u8 modulus[256];
26 	u8 checksum[20];
27 } __packed;
28 
29 #define READ_PUBEK_RESULT_MIN_BODY_SIZE (28 + 256)
30 #define TPM_ORD_READPUBEK 124
31 
32 static ssize_t pubek_show(struct device *dev, struct device_attribute *attr,
33 			  char *buf)
34 {
35 	struct tpm_buf tpm_buf;
36 	struct tpm_readpubek_out *out;
37 	int i;
38 	char *str = buf;
39 	struct tpm_chip *chip = to_tpm_chip(dev);
40 	char anti_replay[20];
41 
42 	memset(&anti_replay, 0, sizeof(anti_replay));
43 
44 	if (tpm_try_get_ops(chip))
45 		return 0;
46 
47 	if (tpm_buf_init(&tpm_buf, TPM_TAG_RQU_COMMAND, TPM_ORD_READPUBEK))
48 		goto out_ops;
49 
50 	tpm_buf_append(&tpm_buf, anti_replay, sizeof(anti_replay));
51 
52 	if (tpm_transmit_cmd(chip, &tpm_buf, READ_PUBEK_RESULT_MIN_BODY_SIZE,
53 			     "attempting to read the PUBEK"))
54 		goto out_buf;
55 
56 	out = (struct tpm_readpubek_out *)&tpm_buf.data[10];
57 	str +=
58 	    sprintf(str,
59 		    "Algorithm: %4ph\n"
60 		    "Encscheme: %2ph\n"
61 		    "Sigscheme: %2ph\n"
62 		    "Parameters: %12ph\n"
63 		    "Modulus length: %d\n"
64 		    "Modulus:\n",
65 		    out->algorithm,
66 		    out->encscheme,
67 		    out->sigscheme,
68 		    out->parameters,
69 		    be32_to_cpu(out->keysize));
70 
71 	for (i = 0; i < 256; i += 16)
72 		str += sprintf(str, "%16ph\n", &out->modulus[i]);
73 
74 out_buf:
75 	tpm_buf_destroy(&tpm_buf);
76 out_ops:
77 	tpm_put_ops(chip);
78 	return str - buf;
79 }
80 static DEVICE_ATTR_RO(pubek);
81 
82 static ssize_t pcrs_show(struct device *dev, struct device_attribute *attr,
83 			 char *buf)
84 {
85 	cap_t cap;
86 	u8 digest[TPM_DIGEST_SIZE];
87 	u32 i, j, num_pcrs;
88 	char *str = buf;
89 	struct tpm_chip *chip = to_tpm_chip(dev);
90 
91 	if (tpm_try_get_ops(chip))
92 		return 0;
93 
94 	if (tpm1_getcap(chip, TPM_CAP_PROP_PCR, &cap,
95 			"attempting to determine the number of PCRS",
96 			sizeof(cap.num_pcrs))) {
97 		tpm_put_ops(chip);
98 		return 0;
99 	}
100 
101 	num_pcrs = be32_to_cpu(cap.num_pcrs);
102 	for (i = 0; i < num_pcrs; i++) {
103 		if (tpm1_pcr_read(chip, i, digest)) {
104 			str = buf;
105 			break;
106 		}
107 		str += sprintf(str, "PCR-%02d: ", i);
108 		for (j = 0; j < TPM_DIGEST_SIZE; j++)
109 			str += sprintf(str, "%02X ", digest[j]);
110 		str += sprintf(str, "\n");
111 	}
112 	tpm_put_ops(chip);
113 	return str - buf;
114 }
115 static DEVICE_ATTR_RO(pcrs);
116 
117 static ssize_t enabled_show(struct device *dev, struct device_attribute *attr,
118 		     char *buf)
119 {
120 	struct tpm_chip *chip = to_tpm_chip(dev);
121 	ssize_t rc = 0;
122 	cap_t cap;
123 
124 	if (tpm_try_get_ops(chip))
125 		return 0;
126 
127 	if (tpm1_getcap(chip, TPM_CAP_FLAG_PERM, &cap,
128 			"attempting to determine the permanent enabled state",
129 			sizeof(cap.perm_flags)))
130 		goto out_ops;
131 
132 	rc = sprintf(buf, "%d\n", !cap.perm_flags.disable);
133 out_ops:
134 	tpm_put_ops(chip);
135 	return rc;
136 }
137 static DEVICE_ATTR_RO(enabled);
138 
139 static ssize_t active_show(struct device *dev, struct device_attribute *attr,
140 		    char *buf)
141 {
142 	struct tpm_chip *chip = to_tpm_chip(dev);
143 	ssize_t rc = 0;
144 	cap_t cap;
145 
146 	if (tpm_try_get_ops(chip))
147 		return 0;
148 
149 	if (tpm1_getcap(chip, TPM_CAP_FLAG_PERM, &cap,
150 			"attempting to determine the permanent active state",
151 			sizeof(cap.perm_flags)))
152 		goto out_ops;
153 
154 	rc = sprintf(buf, "%d\n", !cap.perm_flags.deactivated);
155 out_ops:
156 	tpm_put_ops(chip);
157 	return rc;
158 }
159 static DEVICE_ATTR_RO(active);
160 
161 static ssize_t owned_show(struct device *dev, struct device_attribute *attr,
162 			  char *buf)
163 {
164 	struct tpm_chip *chip = to_tpm_chip(dev);
165 	ssize_t rc = 0;
166 	cap_t cap;
167 
168 	if (tpm_try_get_ops(chip))
169 		return 0;
170 
171 	if (tpm1_getcap(to_tpm_chip(dev), TPM_CAP_PROP_OWNER, &cap,
172 			"attempting to determine the owner state",
173 			sizeof(cap.owned)))
174 		goto out_ops;
175 
176 	rc = sprintf(buf, "%d\n", cap.owned);
177 out_ops:
178 	tpm_put_ops(chip);
179 	return rc;
180 }
181 static DEVICE_ATTR_RO(owned);
182 
183 static ssize_t temp_deactivated_show(struct device *dev,
184 				     struct device_attribute *attr, char *buf)
185 {
186 	struct tpm_chip *chip = to_tpm_chip(dev);
187 	ssize_t rc = 0;
188 	cap_t cap;
189 
190 	if (tpm_try_get_ops(chip))
191 		return 0;
192 
193 	if (tpm1_getcap(to_tpm_chip(dev), TPM_CAP_FLAG_VOL, &cap,
194 			"attempting to determine the temporary state",
195 			sizeof(cap.stclear_flags)))
196 		goto out_ops;
197 
198 	rc = sprintf(buf, "%d\n", cap.stclear_flags.deactivated);
199 out_ops:
200 	tpm_put_ops(chip);
201 	return rc;
202 }
203 static DEVICE_ATTR_RO(temp_deactivated);
204 
205 static ssize_t caps_show(struct device *dev, struct device_attribute *attr,
206 			 char *buf)
207 {
208 	struct tpm_chip *chip = to_tpm_chip(dev);
209 	struct tpm1_version *version;
210 	ssize_t rc = 0;
211 	char *str = buf;
212 	cap_t cap;
213 
214 	if (tpm_try_get_ops(chip))
215 		return 0;
216 
217 	if (tpm1_getcap(chip, TPM_CAP_PROP_MANUFACTURER, &cap,
218 			"attempting to determine the manufacturer",
219 			sizeof(cap.manufacturer_id)))
220 		goto out_ops;
221 
222 	str += sprintf(str, "Manufacturer: 0x%x\n",
223 		       be32_to_cpu(cap.manufacturer_id));
224 
225 	/* TPM 1.2 */
226 	if (!tpm1_getcap(chip, TPM_CAP_VERSION_1_2, &cap,
227 			 "attempting to determine the 1.2 version",
228 			 sizeof(cap.version2))) {
229 		version = &cap.version2.version;
230 		goto out_print;
231 	}
232 
233 	/* TPM 1.1 */
234 	if (tpm1_getcap(chip, TPM_CAP_VERSION_1_1, &cap,
235 			"attempting to determine the 1.1 version",
236 			sizeof(cap.version1))) {
237 		goto out_ops;
238 	}
239 
240 	version = &cap.version1;
241 
242 out_print:
243 	str += sprintf(str,
244 		       "TCG version: %d.%d\nFirmware version: %d.%d\n",
245 		       version->major, version->minor,
246 		       version->rev_major, version->rev_minor);
247 
248 	rc = str - buf;
249 
250 out_ops:
251 	tpm_put_ops(chip);
252 	return rc;
253 }
254 static DEVICE_ATTR_RO(caps);
255 
256 static ssize_t cancel_store(struct device *dev, struct device_attribute *attr,
257 			    const char *buf, size_t count)
258 {
259 	struct tpm_chip *chip = to_tpm_chip(dev);
260 
261 	if (tpm_try_get_ops(chip))
262 		return 0;
263 
264 	chip->ops->cancel(chip);
265 	tpm_put_ops(chip);
266 	return count;
267 }
268 static DEVICE_ATTR_WO(cancel);
269 
270 static ssize_t durations_show(struct device *dev, struct device_attribute *attr,
271 			      char *buf)
272 {
273 	struct tpm_chip *chip = to_tpm_chip(dev);
274 
275 	if (chip->duration[TPM_LONG] == 0)
276 		return 0;
277 
278 	return sprintf(buf, "%d %d %d [%s]\n",
279 		       jiffies_to_usecs(chip->duration[TPM_SHORT]),
280 		       jiffies_to_usecs(chip->duration[TPM_MEDIUM]),
281 		       jiffies_to_usecs(chip->duration[TPM_LONG]),
282 		       chip->duration_adjusted
283 		       ? "adjusted" : "original");
284 }
285 static DEVICE_ATTR_RO(durations);
286 
287 static ssize_t timeouts_show(struct device *dev, struct device_attribute *attr,
288 			     char *buf)
289 {
290 	struct tpm_chip *chip = to_tpm_chip(dev);
291 
292 	return sprintf(buf, "%d %d %d %d [%s]\n",
293 		       jiffies_to_usecs(chip->timeout_a),
294 		       jiffies_to_usecs(chip->timeout_b),
295 		       jiffies_to_usecs(chip->timeout_c),
296 		       jiffies_to_usecs(chip->timeout_d),
297 		       chip->timeout_adjusted
298 		       ? "adjusted" : "original");
299 }
300 static DEVICE_ATTR_RO(timeouts);
301 
302 static ssize_t tpm_version_major_show(struct device *dev,
303 				  struct device_attribute *attr, char *buf)
304 {
305 	struct tpm_chip *chip = to_tpm_chip(dev);
306 
307 	return sprintf(buf, "%s\n", chip->flags & TPM_CHIP_FLAG_TPM2
308 		       ? "2" : "1");
309 }
310 static DEVICE_ATTR_RO(tpm_version_major);
311 
312 static struct attribute *tpm1_dev_attrs[] = {
313 	&dev_attr_pubek.attr,
314 	&dev_attr_pcrs.attr,
315 	&dev_attr_enabled.attr,
316 	&dev_attr_active.attr,
317 	&dev_attr_owned.attr,
318 	&dev_attr_temp_deactivated.attr,
319 	&dev_attr_caps.attr,
320 	&dev_attr_cancel.attr,
321 	&dev_attr_durations.attr,
322 	&dev_attr_timeouts.attr,
323 	&dev_attr_tpm_version_major.attr,
324 	NULL,
325 };
326 
327 static struct attribute *tpm2_dev_attrs[] = {
328 	&dev_attr_tpm_version_major.attr,
329 	NULL
330 };
331 
332 static const struct attribute_group tpm1_dev_group = {
333 	.attrs = tpm1_dev_attrs,
334 };
335 
336 static const struct attribute_group tpm2_dev_group = {
337 	.attrs = tpm2_dev_attrs,
338 };
339 
340 struct tpm_pcr_attr {
341 	int alg_id;
342 	int pcr;
343 	struct device_attribute attr;
344 };
345 
346 #define to_tpm_pcr_attr(a) container_of(a, struct tpm_pcr_attr, attr)
347 
348 static ssize_t pcr_value_show(struct device *dev,
349 			      struct device_attribute *attr,
350 			      char *buf)
351 {
352 	struct tpm_pcr_attr *ha = to_tpm_pcr_attr(attr);
353 	struct tpm_chip *chip = to_tpm_chip(dev);
354 	struct tpm_digest digest;
355 	int i;
356 	int digest_size = 0;
357 	int rc;
358 	char *str = buf;
359 
360 	for (i = 0; i < chip->nr_allocated_banks; i++)
361 		if (ha->alg_id == chip->allocated_banks[i].alg_id)
362 			digest_size = chip->allocated_banks[i].digest_size;
363 	/* should never happen */
364 	if (!digest_size)
365 		return -EINVAL;
366 
367 	digest.alg_id = ha->alg_id;
368 	rc = tpm_pcr_read(chip, ha->pcr, &digest);
369 	if (rc)
370 		return rc;
371 	for (i = 0; i < digest_size; i++)
372 		str += sprintf(str, "%02X", digest.digest[i]);
373 	str += sprintf(str, "\n");
374 
375 	return str - buf;
376 }
377 
378 /*
379  * The following set of defines represents all the magic to build
380  * the per hash attribute groups for displaying each bank of PCRs.
381  * The only slight problem with this approach is that every PCR is
382  * hard coded to be present, so you don't know if an PCR is missing
383  * until a cat of the file returns -EINVAL
384  *
385  * Also note you must ignore checkpatch warnings in this macro
386  * code. This is deep macro magic that checkpatch.pl doesn't
387  * understand.
388  */
389 
390 /* Note, this must match TPM2_PLATFORM_PCR which is fixed at 24. */
391 #define _TPM_HELPER(_alg, _hash, F) \
392 	F(_alg, _hash, 0)	    \
393 	F(_alg, _hash, 1)	    \
394 	F(_alg, _hash, 2)	    \
395 	F(_alg, _hash, 3)	    \
396 	F(_alg, _hash, 4)	    \
397 	F(_alg, _hash, 5)	    \
398 	F(_alg, _hash, 6)	    \
399 	F(_alg, _hash, 7)	    \
400 	F(_alg, _hash, 8)	    \
401 	F(_alg, _hash, 9)	    \
402 	F(_alg, _hash, 10)	    \
403 	F(_alg, _hash, 11)	    \
404 	F(_alg, _hash, 12)	    \
405 	F(_alg, _hash, 13)	    \
406 	F(_alg, _hash, 14)	    \
407 	F(_alg, _hash, 15)	    \
408 	F(_alg, _hash, 16)	    \
409 	F(_alg, _hash, 17)	    \
410 	F(_alg, _hash, 18)	    \
411 	F(_alg, _hash, 19)	    \
412 	F(_alg, _hash, 20)	    \
413 	F(_alg, _hash, 21)	    \
414 	F(_alg, _hash, 22)	    \
415 	F(_alg, _hash, 23)
416 
417 /* ignore checkpatch warning about trailing ; in macro. */
418 #define PCR_ATTR(_alg, _hash, _pcr)				   \
419 	static struct tpm_pcr_attr dev_attr_pcr_##_hash##_##_pcr = {	\
420 		.alg_id = _alg,					   \
421 		.pcr = _pcr,					   \
422 		.attr = {					   \
423 			.attr = {				   \
424 				.name = __stringify(_pcr),	   \
425 				.mode = 0444			   \
426 			},					   \
427 			.show = pcr_value_show			   \
428 		}						   \
429 	};
430 
431 #define PCR_ATTRS(_alg, _hash)			\
432 	_TPM_HELPER(_alg, _hash, PCR_ATTR)
433 
434 /* ignore checkpatch warning about trailing , in macro. */
435 #define PCR_ATTR_VAL(_alg, _hash, _pcr)		\
436 	&dev_attr_pcr_##_hash##_##_pcr.attr.attr,
437 
438 #define PCR_ATTR_GROUP_ARRAY(_alg, _hash)		       \
439 	static struct attribute *pcr_group_attrs_##_hash[] = { \
440 		_TPM_HELPER(_alg, _hash, PCR_ATTR_VAL)	       \
441 		NULL					       \
442 	}
443 
444 #define PCR_ATTR_GROUP(_alg, _hash)			    \
445 	static struct attribute_group pcr_group_##_hash = { \
446 		.name = "pcr-" __stringify(_hash),	    \
447 		.attrs = pcr_group_attrs_##_hash	    \
448 	}
449 
450 #define PCR_ATTR_BUILD(_alg, _hash)	   \
451 	PCR_ATTRS(_alg, _hash)		   \
452 	PCR_ATTR_GROUP_ARRAY(_alg, _hash); \
453 	PCR_ATTR_GROUP(_alg, _hash)
454 /*
455  * End of macro structure to build an attribute group containing 24
456  * PCR value files for each supported hash algorithm
457  */
458 
459 /*
460  * The next set of macros implements the cleverness for each hash to
461  * build a static attribute group called pcr_group_<hash> which can be
462  * added to chip->groups[].
463  *
464  * The first argument is the TPM algorithm id and the second is the
465  * hash used as both the suffix and the group name.  Note: the group
466  * name is a directory in the top level tpm class with the name
467  * pcr-<hash>, so it must not clash with any other names already
468  * in the sysfs directory.
469  */
470 PCR_ATTR_BUILD(TPM_ALG_SHA1, sha1);
471 PCR_ATTR_BUILD(TPM_ALG_SHA256, sha256);
472 PCR_ATTR_BUILD(TPM_ALG_SHA384, sha384);
473 PCR_ATTR_BUILD(TPM_ALG_SHA512, sha512);
474 PCR_ATTR_BUILD(TPM_ALG_SM3_256, sm3);
475 
476 
477 void tpm_sysfs_add_device(struct tpm_chip *chip)
478 {
479 	int i;
480 
481 	WARN_ON(chip->groups_cnt != 0);
482 
483 	if (tpm_is_firmware_upgrade(chip))
484 		return;
485 
486 	if (chip->flags & TPM_CHIP_FLAG_TPM2)
487 		chip->groups[chip->groups_cnt++] = &tpm2_dev_group;
488 	else
489 		chip->groups[chip->groups_cnt++] = &tpm1_dev_group;
490 
491 	/* add one group for each bank hash */
492 	for (i = 0; i < chip->nr_allocated_banks; i++) {
493 		switch (chip->allocated_banks[i].alg_id) {
494 		case TPM_ALG_SHA1:
495 			chip->groups[chip->groups_cnt++] = &pcr_group_sha1;
496 			break;
497 		case TPM_ALG_SHA256:
498 			chip->groups[chip->groups_cnt++] = &pcr_group_sha256;
499 			break;
500 		case TPM_ALG_SHA384:
501 			chip->groups[chip->groups_cnt++] = &pcr_group_sha384;
502 			break;
503 		case TPM_ALG_SHA512:
504 			chip->groups[chip->groups_cnt++] = &pcr_group_sha512;
505 			break;
506 		case TPM_ALG_SM3_256:
507 			chip->groups[chip->groups_cnt++] = &pcr_group_sm3;
508 			break;
509 		default:
510 			/*
511 			 * If triggers, send a patch to add both a
512 			 * PCR_ATTR_BUILD() macro above for the
513 			 * missing algorithm as well as an additional
514 			 * case in this switch statement.
515 			 */
516 			dev_err(&chip->dev,
517 				"TPM with unsupported bank algorithm 0x%04x",
518 				chip->allocated_banks[i].alg_id);
519 			break;
520 		}
521 	}
522 
523 	/*
524 	 * This will only trigger if someone has added an additional
525 	 * hash to the tpm_algorithms enum without incrementing
526 	 * TPM_MAX_HASHES.
527 	 */
528 	WARN_ON(chip->groups_cnt > TPM_MAX_HASHES + 1);
529 }
530