xref: /openbmc/linux/drivers/char/tpm/tpm-sysfs.c (revision 5b394b2d)
1 /*
2  * Copyright (C) 2004 IBM Corporation
3  * Authors:
4  * Leendert van Doorn <leendert@watson.ibm.com>
5  * Dave Safford <safford@watson.ibm.com>
6  * Reiner Sailer <sailer@watson.ibm.com>
7  * Kylene Hall <kjhall@us.ibm.com>
8  *
9  * Copyright (C) 2013 Obsidian Research Corp
10  * Jason Gunthorpe <jgunthorpe@obsidianresearch.com>
11  *
12  * sysfs filesystem inspection interface to the TPM
13  *
14  * This program is free software; you can redistribute it and/or
15  * modify it under the terms of the GNU General Public License as
16  * published by the Free Software Foundation, version 2 of the
17  * License.
18  *
19  */
20 #include <linux/device.h>
21 #include "tpm.h"
22 
23 struct tpm_readpubek_out {
24 	u8 algorithm[4];
25 	u8 encscheme[2];
26 	u8 sigscheme[2];
27 	__be32 paramsize;
28 	u8 parameters[12];
29 	__be32 keysize;
30 	u8 modulus[256];
31 	u8 checksum[20];
32 } __packed;
33 
34 #define READ_PUBEK_RESULT_MIN_BODY_SIZE (28 + 256)
35 #define TPM_ORD_READPUBEK 124
36 
37 static ssize_t pubek_show(struct device *dev, struct device_attribute *attr,
38 			  char *buf)
39 {
40 	struct tpm_buf tpm_buf;
41 	struct tpm_readpubek_out *out;
42 	ssize_t rc;
43 	int i;
44 	char *str = buf;
45 	struct tpm_chip *chip = to_tpm_chip(dev);
46 	char anti_replay[20];
47 
48 	memset(&anti_replay, 0, sizeof(anti_replay));
49 
50 	rc = tpm_buf_init(&tpm_buf, TPM_TAG_RQU_COMMAND, TPM_ORD_READPUBEK);
51 	if (rc)
52 		return rc;
53 
54 	tpm_buf_append(&tpm_buf, anti_replay, sizeof(anti_replay));
55 
56 	rc = tpm_transmit_cmd(chip, NULL, tpm_buf.data, PAGE_SIZE,
57 			      READ_PUBEK_RESULT_MIN_BODY_SIZE, 0,
58 			      "attempting to read the PUBEK");
59 	if (rc) {
60 		tpm_buf_destroy(&tpm_buf);
61 		return 0;
62 	}
63 
64 	out = (struct tpm_readpubek_out *)&tpm_buf.data[10];
65 	str +=
66 	    sprintf(str,
67 		    "Algorithm: %02X %02X %02X %02X\n"
68 		    "Encscheme: %02X %02X\n"
69 		    "Sigscheme: %02X %02X\n"
70 		    "Parameters: %02X %02X %02X %02X "
71 		    "%02X %02X %02X %02X "
72 		    "%02X %02X %02X %02X\n"
73 		    "Modulus length: %d\n"
74 		    "Modulus:\n",
75 		    out->algorithm[0], out->algorithm[1], out->algorithm[2],
76 		    out->algorithm[3],
77 		    out->encscheme[0], out->encscheme[1],
78 		    out->sigscheme[0], out->sigscheme[1],
79 		    out->parameters[0], out->parameters[1],
80 		    out->parameters[2], out->parameters[3],
81 		    out->parameters[4], out->parameters[5],
82 		    out->parameters[6], out->parameters[7],
83 		    out->parameters[8], out->parameters[9],
84 		    out->parameters[10], out->parameters[11],
85 		    be32_to_cpu(out->keysize));
86 
87 	for (i = 0; i < 256; i++) {
88 		str += sprintf(str, "%02X ", out->modulus[i]);
89 		if ((i + 1) % 16 == 0)
90 			str += sprintf(str, "\n");
91 	}
92 
93 	rc = str - buf;
94 	tpm_buf_destroy(&tpm_buf);
95 	return rc;
96 }
97 static DEVICE_ATTR_RO(pubek);
98 
99 static ssize_t pcrs_show(struct device *dev, struct device_attribute *attr,
100 			 char *buf)
101 {
102 	cap_t cap;
103 	u8 digest[TPM_DIGEST_SIZE];
104 	ssize_t rc;
105 	int i, j, num_pcrs;
106 	char *str = buf;
107 	struct tpm_chip *chip = to_tpm_chip(dev);
108 
109 	rc = tpm_getcap(chip, TPM_CAP_PROP_PCR, &cap,
110 			"attempting to determine the number of PCRS",
111 			sizeof(cap.num_pcrs));
112 	if (rc)
113 		return 0;
114 
115 	num_pcrs = be32_to_cpu(cap.num_pcrs);
116 	for (i = 0; i < num_pcrs; i++) {
117 		rc = tpm_pcr_read_dev(chip, i, digest);
118 		if (rc)
119 			break;
120 		str += sprintf(str, "PCR-%02d: ", i);
121 		for (j = 0; j < TPM_DIGEST_SIZE; j++)
122 			str += sprintf(str, "%02X ", digest[j]);
123 		str += sprintf(str, "\n");
124 	}
125 	return str - buf;
126 }
127 static DEVICE_ATTR_RO(pcrs);
128 
129 static ssize_t enabled_show(struct device *dev, struct device_attribute *attr,
130 		     char *buf)
131 {
132 	cap_t cap;
133 	ssize_t rc;
134 
135 	rc = tpm_getcap(to_tpm_chip(dev), TPM_CAP_FLAG_PERM, &cap,
136 			"attempting to determine the permanent enabled state",
137 			sizeof(cap.perm_flags));
138 	if (rc)
139 		return 0;
140 
141 	rc = sprintf(buf, "%d\n", !cap.perm_flags.disable);
142 	return rc;
143 }
144 static DEVICE_ATTR_RO(enabled);
145 
146 static ssize_t active_show(struct device *dev, struct device_attribute *attr,
147 		    char *buf)
148 {
149 	cap_t cap;
150 	ssize_t rc;
151 
152 	rc = tpm_getcap(to_tpm_chip(dev), TPM_CAP_FLAG_PERM, &cap,
153 			"attempting to determine the permanent active state",
154 			sizeof(cap.perm_flags));
155 	if (rc)
156 		return 0;
157 
158 	rc = sprintf(buf, "%d\n", !cap.perm_flags.deactivated);
159 	return rc;
160 }
161 static DEVICE_ATTR_RO(active);
162 
163 static ssize_t owned_show(struct device *dev, struct device_attribute *attr,
164 			  char *buf)
165 {
166 	cap_t cap;
167 	ssize_t rc;
168 
169 	rc = tpm_getcap(to_tpm_chip(dev), TPM_CAP_PROP_OWNER, &cap,
170 			"attempting to determine the owner state",
171 			sizeof(cap.owned));
172 	if (rc)
173 		return 0;
174 
175 	rc = sprintf(buf, "%d\n", cap.owned);
176 	return rc;
177 }
178 static DEVICE_ATTR_RO(owned);
179 
180 static ssize_t temp_deactivated_show(struct device *dev,
181 				     struct device_attribute *attr, char *buf)
182 {
183 	cap_t cap;
184 	ssize_t rc;
185 
186 	rc = tpm_getcap(to_tpm_chip(dev), TPM_CAP_FLAG_VOL, &cap,
187 			"attempting to determine the temporary state",
188 			sizeof(cap.stclear_flags));
189 	if (rc)
190 		return 0;
191 
192 	rc = sprintf(buf, "%d\n", cap.stclear_flags.deactivated);
193 	return rc;
194 }
195 static DEVICE_ATTR_RO(temp_deactivated);
196 
197 static ssize_t caps_show(struct device *dev, struct device_attribute *attr,
198 			 char *buf)
199 {
200 	struct tpm_chip *chip = to_tpm_chip(dev);
201 	cap_t cap;
202 	ssize_t rc;
203 	char *str = buf;
204 
205 	rc = tpm_getcap(chip, TPM_CAP_PROP_MANUFACTURER, &cap,
206 			"attempting to determine the manufacturer",
207 			sizeof(cap.manufacturer_id));
208 	if (rc)
209 		return 0;
210 	str += sprintf(str, "Manufacturer: 0x%x\n",
211 		       be32_to_cpu(cap.manufacturer_id));
212 
213 	/* Try to get a TPM version 1.2 TPM_CAP_VERSION_INFO */
214 	rc = tpm_getcap(chip, TPM_CAP_VERSION_1_2, &cap,
215 			"attempting to determine the 1.2 version",
216 			sizeof(cap.tpm_version_1_2));
217 	if (!rc) {
218 		str += sprintf(str,
219 			       "TCG version: %d.%d\nFirmware version: %d.%d\n",
220 			       cap.tpm_version_1_2.Major,
221 			       cap.tpm_version_1_2.Minor,
222 			       cap.tpm_version_1_2.revMajor,
223 			       cap.tpm_version_1_2.revMinor);
224 	} else {
225 		/* Otherwise just use TPM_STRUCT_VER */
226 		rc = tpm_getcap(chip, TPM_CAP_VERSION_1_1, &cap,
227 				"attempting to determine the 1.1 version",
228 				sizeof(cap.tpm_version));
229 		if (rc)
230 			return 0;
231 		str += sprintf(str,
232 			       "TCG version: %d.%d\nFirmware version: %d.%d\n",
233 			       cap.tpm_version.Major,
234 			       cap.tpm_version.Minor,
235 			       cap.tpm_version.revMajor,
236 			       cap.tpm_version.revMinor);
237 	}
238 
239 	return str - buf;
240 }
241 static DEVICE_ATTR_RO(caps);
242 
243 static ssize_t cancel_store(struct device *dev, struct device_attribute *attr,
244 			    const char *buf, size_t count)
245 {
246 	struct tpm_chip *chip = to_tpm_chip(dev);
247 	if (chip == NULL)
248 		return 0;
249 
250 	chip->ops->cancel(chip);
251 	return count;
252 }
253 static DEVICE_ATTR_WO(cancel);
254 
255 static ssize_t durations_show(struct device *dev, struct device_attribute *attr,
256 			      char *buf)
257 {
258 	struct tpm_chip *chip = to_tpm_chip(dev);
259 
260 	if (chip->duration[TPM_LONG] == 0)
261 		return 0;
262 
263 	return sprintf(buf, "%d %d %d [%s]\n",
264 		       jiffies_to_usecs(chip->duration[TPM_SHORT]),
265 		       jiffies_to_usecs(chip->duration[TPM_MEDIUM]),
266 		       jiffies_to_usecs(chip->duration[TPM_LONG]),
267 		       chip->duration_adjusted
268 		       ? "adjusted" : "original");
269 }
270 static DEVICE_ATTR_RO(durations);
271 
272 static ssize_t timeouts_show(struct device *dev, struct device_attribute *attr,
273 			     char *buf)
274 {
275 	struct tpm_chip *chip = to_tpm_chip(dev);
276 
277 	return sprintf(buf, "%d %d %d %d [%s]\n",
278 		       jiffies_to_usecs(chip->timeout_a),
279 		       jiffies_to_usecs(chip->timeout_b),
280 		       jiffies_to_usecs(chip->timeout_c),
281 		       jiffies_to_usecs(chip->timeout_d),
282 		       chip->timeout_adjusted
283 		       ? "adjusted" : "original");
284 }
285 static DEVICE_ATTR_RO(timeouts);
286 
287 static struct attribute *tpm_dev_attrs[] = {
288 	&dev_attr_pubek.attr,
289 	&dev_attr_pcrs.attr,
290 	&dev_attr_enabled.attr,
291 	&dev_attr_active.attr,
292 	&dev_attr_owned.attr,
293 	&dev_attr_temp_deactivated.attr,
294 	&dev_attr_caps.attr,
295 	&dev_attr_cancel.attr,
296 	&dev_attr_durations.attr,
297 	&dev_attr_timeouts.attr,
298 	NULL,
299 };
300 
301 static const struct attribute_group tpm_dev_group = {
302 	.attrs = tpm_dev_attrs,
303 };
304 
305 void tpm_sysfs_add_device(struct tpm_chip *chip)
306 {
307 	/* XXX: If you wish to remove this restriction, you must first update
308 	 * tpm_sysfs to explicitly lock chip->ops.
309 	 */
310 	if (chip->flags & TPM_CHIP_FLAG_TPM2)
311 		return;
312 
313 	/* The sysfs routines rely on an implicit tpm_try_get_ops, device_del
314 	 * is called before ops is null'd and the sysfs core synchronizes this
315 	 * removal so that no callbacks are running or can run again
316 	 */
317 	WARN_ON(chip->groups_cnt != 0);
318 	chip->groups[chip->groups_cnt++] = &tpm_dev_group;
319 }
320