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
|
// SPDX-License-Identifier: GPL-2.0-or-later
/*
* Copyright (C) 2005, 2012 IBM Corporation
*
* Authors:
* Kent Yoder <key@linux.vnet.ibm.com>
* Seiji Munetoh <munetoh@jp.ibm.com>
* Stefan Berger <stefanb@us.ibm.com>
* Reiner Sailer <sailer@watson.ibm.com>
* Kylene Hall <kjhall@us.ibm.com>
* Nayna Jain <nayna@linux.vnet.ibm.com>
*
* Access to the event log created by a system's firmware / BIOS
*/
#include <linux/seq_file.h>
#include <linux/fs.h>
#include <linux/security.h>
#include <linux/module.h>
#include <linux/tpm_eventlog.h>
#include "../tpm.h"
#include "common.h"
static int tpm_bios_measurements_open(struct inode *inode,
struct file *file)
{
int err;
struct seq_file *seq;
struct tpm_chip_seqops *chip_seqops;
const struct seq_operations *seqops;
struct tpm_chip *chip;
inode_lock(inode);
if (!inode->i_private) {
inode_unlock(inode);
return -ENODEV;
}
chip_seqops = inode->i_private;
seqops = chip_seqops->seqops;
chip = chip_seqops->chip;
get_device(&chip->dev);
inode_unlock(inode);
/* now register seq file */
err = seq_open(file, seqops);
if (!err) {
seq = file->private_data;
seq->private = chip;
} else {
put_device(&chip->dev);
}
return err;
}
static int tpm_bios_measurements_release(struct inode *inode,
struct file *file)
{
struct seq_file *seq = file->private_data;
struct tpm_chip *chip = seq->private;
put_device(&chip->dev);
return seq_release(inode, file);
}
static const struct file_operations tpm_bios_measurements_ops = {
.owner = THIS_MODULE,
.open = tpm_bios_measurements_open,
.read = seq_read,
.llseek = seq_lseek,
.release = tpm_bios_measurements_release,
};
static int tpm_read_log(struct tpm_chip *chip)
{
int rc;
if (chip->log.bios_event_log != NULL) {
dev_dbg(&chip->dev,
"%s: ERROR - event log already initialized\n",
__func__);
return -EFAULT;
}
rc = tpm_read_log_acpi(chip);
if (rc != -ENODEV)
return rc;
rc = tpm_read_log_efi(chip);
if (rc != -ENODEV)
return rc;
return tpm_read_log_of(chip);
}
/*
* tpm_bios_log_setup() - Read the event log from the firmware
* @chip: TPM chip to use.
*
* If an event log is found then the securityfs files are setup to
* export it to userspace, otherwise nothing is done.
*/
void tpm_bios_log_setup(struct tpm_chip *chip)
{
const char *name = dev_name(&chip->dev);
unsigned int cnt;
int log_version;
int rc = 0;
if (chip->flags & TPM_CHIP_FLAG_VIRTUAL)
return;
rc = tpm_read_log(chip);
if (rc < 0)
return;
log_version = rc;
cnt = 0;
chip->bios_dir[cnt] = securityfs_create_dir(name, NULL);
/* NOTE: securityfs_create_dir can return ENODEV if securityfs is
* compiled out. The caller should ignore the ENODEV return code.
*/
if (IS_ERR(chip->bios_dir[cnt]))
goto err;
cnt++;
chip->bin_log_seqops.chip = chip;
if (log_version == EFI_TCG2_EVENT_LOG_FORMAT_TCG_2)
chip->bin_log_seqops.seqops =
&tpm2_binary_b_measurements_seqops;
else
chip->bin_log_seqops.seqops =
&tpm1_binary_b_measurements_seqops;
chip->bios_dir[cnt] =
securityfs_create_file("binary_bios_measurements",
0440, chip->bios_dir[0],
(void *)&chip->bin_log_seqops,
&tpm_bios_measurements_ops);
if (IS_ERR(chip->bios_dir[cnt]))
goto err;
cnt++;
if (!(chip->flags & TPM_CHIP_FLAG_TPM2)) {
chip->ascii_log_seqops.chip = chip;
chip->ascii_log_seqops.seqops =
&tpm1_ascii_b_measurements_seqops;
chip->bios_dir[cnt] =
securityfs_create_file("ascii_bios_measurements",
0440, chip->bios_dir[0],
(void *)&chip->ascii_log_seqops,
&tpm_bios_measurements_ops);
if (IS_ERR(chip->bios_dir[cnt]))
goto err;
cnt++;
}
return;
err:
chip->bios_dir[cnt] = NULL;
tpm_bios_log_teardown(chip);
return;
}
void tpm_bios_log_teardown(struct tpm_chip *chip)
{
int i;
struct inode *inode;
/* securityfs_remove currently doesn't take care of handling sync
* between removal and opening of pseudo files. To handle this, a
* workaround is added by making i_private = NULL here during removal
* and to check it during open(), both within inode_lock()/unlock().
* This design ensures that open() either safely gets kref or fails.
*/
for (i = (TPM_NUM_EVENT_LOG_FILES - 1); i >= 0; i--) {
if (chip->bios_dir[i]) {
inode = d_inode(chip->bios_dir[i]);
inode_lock(inode);
inode->i_private = NULL;
inode_unlock(inode);
securityfs_remove(chip->bios_dir[i]);
}
}
}
|
