xref: /openbmc/linux/drivers/char/tpm/tpm-sysfs.c (revision b593bce5)
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: %02X %02X %02X %02X\n"
60 		    "Encscheme: %02X %02X\n"
61 		    "Sigscheme: %02X %02X\n"
62 		    "Parameters: %02X %02X %02X %02X "
63 		    "%02X %02X %02X %02X "
64 		    "%02X %02X %02X %02X\n"
65 		    "Modulus length: %d\n"
66 		    "Modulus:\n",
67 		    out->algorithm[0], out->algorithm[1], out->algorithm[2],
68 		    out->algorithm[3],
69 		    out->encscheme[0], out->encscheme[1],
70 		    out->sigscheme[0], out->sigscheme[1],
71 		    out->parameters[0], out->parameters[1],
72 		    out->parameters[2], out->parameters[3],
73 		    out->parameters[4], out->parameters[5],
74 		    out->parameters[6], out->parameters[7],
75 		    out->parameters[8], out->parameters[9],
76 		    out->parameters[10], out->parameters[11],
77 		    be32_to_cpu(out->keysize));
78 
79 	for (i = 0; i < 256; i++) {
80 		str += sprintf(str, "%02X ", out->modulus[i]);
81 		if ((i + 1) % 16 == 0)
82 			str += sprintf(str, "\n");
83 	}
84 
85 out_buf:
86 	tpm_buf_destroy(&tpm_buf);
87 out_ops:
88 	tpm_put_ops(chip);
89 	return str - buf;
90 }
91 static DEVICE_ATTR_RO(pubek);
92 
93 static ssize_t pcrs_show(struct device *dev, struct device_attribute *attr,
94 			 char *buf)
95 {
96 	cap_t cap;
97 	u8 digest[TPM_DIGEST_SIZE];
98 	u32 i, j, num_pcrs;
99 	char *str = buf;
100 	struct tpm_chip *chip = to_tpm_chip(dev);
101 
102 	if (tpm_try_get_ops(chip))
103 		return 0;
104 
105 	if (tpm1_getcap(chip, TPM_CAP_PROP_PCR, &cap,
106 			"attempting to determine the number of PCRS",
107 			sizeof(cap.num_pcrs))) {
108 		tpm_put_ops(chip);
109 		return 0;
110 	}
111 
112 	num_pcrs = be32_to_cpu(cap.num_pcrs);
113 	for (i = 0; i < num_pcrs; i++) {
114 		if (tpm1_pcr_read(chip, i, digest)) {
115 			str = buf;
116 			break;
117 		}
118 		str += sprintf(str, "PCR-%02d: ", i);
119 		for (j = 0; j < TPM_DIGEST_SIZE; j++)
120 			str += sprintf(str, "%02X ", digest[j]);
121 		str += sprintf(str, "\n");
122 	}
123 	tpm_put_ops(chip);
124 	return str - buf;
125 }
126 static DEVICE_ATTR_RO(pcrs);
127 
128 static ssize_t enabled_show(struct device *dev, struct device_attribute *attr,
129 		     char *buf)
130 {
131 	struct tpm_chip *chip = to_tpm_chip(dev);
132 	ssize_t rc = 0;
133 	cap_t cap;
134 
135 	if (tpm_try_get_ops(chip))
136 		return 0;
137 
138 	if (tpm1_getcap(chip, TPM_CAP_FLAG_PERM, &cap,
139 			"attempting to determine the permanent enabled state",
140 			sizeof(cap.perm_flags)))
141 		goto out_ops;
142 
143 	rc = sprintf(buf, "%d\n", !cap.perm_flags.disable);
144 out_ops:
145 	tpm_put_ops(chip);
146 	return rc;
147 }
148 static DEVICE_ATTR_RO(enabled);
149 
150 static ssize_t active_show(struct device *dev, struct device_attribute *attr,
151 		    char *buf)
152 {
153 	struct tpm_chip *chip = to_tpm_chip(dev);
154 	ssize_t rc = 0;
155 	cap_t cap;
156 
157 	if (tpm_try_get_ops(chip))
158 		return 0;
159 
160 	if (tpm1_getcap(chip, TPM_CAP_FLAG_PERM, &cap,
161 			"attempting to determine the permanent active state",
162 			sizeof(cap.perm_flags)))
163 		goto out_ops;
164 
165 	rc = sprintf(buf, "%d\n", !cap.perm_flags.deactivated);
166 out_ops:
167 	tpm_put_ops(chip);
168 	return rc;
169 }
170 static DEVICE_ATTR_RO(active);
171 
172 static ssize_t owned_show(struct device *dev, struct device_attribute *attr,
173 			  char *buf)
174 {
175 	struct tpm_chip *chip = to_tpm_chip(dev);
176 	ssize_t rc = 0;
177 	cap_t cap;
178 
179 	if (tpm_try_get_ops(chip))
180 		return 0;
181 
182 	if (tpm1_getcap(to_tpm_chip(dev), TPM_CAP_PROP_OWNER, &cap,
183 			"attempting to determine the owner state",
184 			sizeof(cap.owned)))
185 		goto out_ops;
186 
187 	rc = sprintf(buf, "%d\n", cap.owned);
188 out_ops:
189 	tpm_put_ops(chip);
190 	return rc;
191 }
192 static DEVICE_ATTR_RO(owned);
193 
194 static ssize_t temp_deactivated_show(struct device *dev,
195 				     struct device_attribute *attr, char *buf)
196 {
197 	struct tpm_chip *chip = to_tpm_chip(dev);
198 	ssize_t rc = 0;
199 	cap_t cap;
200 
201 	if (tpm_try_get_ops(chip))
202 		return 0;
203 
204 	if (tpm1_getcap(to_tpm_chip(dev), TPM_CAP_FLAG_VOL, &cap,
205 			"attempting to determine the temporary state",
206 			sizeof(cap.stclear_flags)))
207 		goto out_ops;
208 
209 	rc = sprintf(buf, "%d\n", cap.stclear_flags.deactivated);
210 out_ops:
211 	tpm_put_ops(chip);
212 	return rc;
213 }
214 static DEVICE_ATTR_RO(temp_deactivated);
215 
216 static ssize_t caps_show(struct device *dev, struct device_attribute *attr,
217 			 char *buf)
218 {
219 	struct tpm_chip *chip = to_tpm_chip(dev);
220 	ssize_t rc = 0;
221 	char *str = buf;
222 	cap_t cap;
223 
224 	if (tpm_try_get_ops(chip))
225 		return 0;
226 
227 	if (tpm1_getcap(chip, TPM_CAP_PROP_MANUFACTURER, &cap,
228 			"attempting to determine the manufacturer",
229 			sizeof(cap.manufacturer_id)))
230 		goto out_ops;
231 
232 	str += sprintf(str, "Manufacturer: 0x%x\n",
233 		       be32_to_cpu(cap.manufacturer_id));
234 
235 	/* Try to get a TPM version 1.2 TPM_CAP_VERSION_INFO */
236 	rc = tpm1_getcap(chip, TPM_CAP_VERSION_1_2, &cap,
237 			 "attempting to determine the 1.2 version",
238 			 sizeof(cap.tpm_version_1_2));
239 	if (!rc) {
240 		str += sprintf(str,
241 			       "TCG version: %d.%d\nFirmware version: %d.%d\n",
242 			       cap.tpm_version_1_2.Major,
243 			       cap.tpm_version_1_2.Minor,
244 			       cap.tpm_version_1_2.revMajor,
245 			       cap.tpm_version_1_2.revMinor);
246 	} else {
247 		/* Otherwise just use TPM_STRUCT_VER */
248 		if (tpm1_getcap(chip, TPM_CAP_VERSION_1_1, &cap,
249 				"attempting to determine the 1.1 version",
250 				sizeof(cap.tpm_version)))
251 			goto out_ops;
252 		str += sprintf(str,
253 			       "TCG version: %d.%d\nFirmware version: %d.%d\n",
254 			       cap.tpm_version.Major,
255 			       cap.tpm_version.Minor,
256 			       cap.tpm_version.revMajor,
257 			       cap.tpm_version.revMinor);
258 	}
259 	rc = str - buf;
260 out_ops:
261 	tpm_put_ops(chip);
262 	return rc;
263 }
264 static DEVICE_ATTR_RO(caps);
265 
266 static ssize_t cancel_store(struct device *dev, struct device_attribute *attr,
267 			    const char *buf, size_t count)
268 {
269 	struct tpm_chip *chip = to_tpm_chip(dev);
270 
271 	if (tpm_try_get_ops(chip))
272 		return 0;
273 
274 	chip->ops->cancel(chip);
275 	tpm_put_ops(chip);
276 	return count;
277 }
278 static DEVICE_ATTR_WO(cancel);
279 
280 static ssize_t durations_show(struct device *dev, struct device_attribute *attr,
281 			      char *buf)
282 {
283 	struct tpm_chip *chip = to_tpm_chip(dev);
284 
285 	if (chip->duration[TPM_LONG] == 0)
286 		return 0;
287 
288 	return sprintf(buf, "%d %d %d [%s]\n",
289 		       jiffies_to_usecs(chip->duration[TPM_SHORT]),
290 		       jiffies_to_usecs(chip->duration[TPM_MEDIUM]),
291 		       jiffies_to_usecs(chip->duration[TPM_LONG]),
292 		       chip->duration_adjusted
293 		       ? "adjusted" : "original");
294 }
295 static DEVICE_ATTR_RO(durations);
296 
297 static ssize_t timeouts_show(struct device *dev, struct device_attribute *attr,
298 			     char *buf)
299 {
300 	struct tpm_chip *chip = to_tpm_chip(dev);
301 
302 	return sprintf(buf, "%d %d %d %d [%s]\n",
303 		       jiffies_to_usecs(chip->timeout_a),
304 		       jiffies_to_usecs(chip->timeout_b),
305 		       jiffies_to_usecs(chip->timeout_c),
306 		       jiffies_to_usecs(chip->timeout_d),
307 		       chip->timeout_adjusted
308 		       ? "adjusted" : "original");
309 }
310 static DEVICE_ATTR_RO(timeouts);
311 
312 static struct attribute *tpm_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 	NULL,
324 };
325 
326 static const struct attribute_group tpm_dev_group = {
327 	.attrs = tpm_dev_attrs,
328 };
329 
330 void tpm_sysfs_add_device(struct tpm_chip *chip)
331 {
332 	/* XXX: If you wish to remove this restriction, you must first update
333 	 * tpm_sysfs to explicitly lock chip->ops.
334 	 */
335 	if (chip->flags & TPM_CHIP_FLAG_TPM2)
336 		return;
337 
338 	/* The sysfs routines rely on an implicit tpm_try_get_ops, device_del
339 	 * is called before ops is null'd and the sysfs core synchronizes this
340 	 * removal so that no callbacks are running or can run again
341 	 */
342 	WARN_ON(chip->groups_cnt != 0);
343 	chip->groups[chip->groups_cnt++] = &tpm_dev_group;
344 }
345