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// 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 = (struct tpm_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;
}
return err;
}
static int tpm_bios_measurements_release(struct inode *inode,
struct file *file)
{
struct seq_file *seq = (struct seq_file *)file->private_data;
struct tpm_chip *chip = (struct tpm_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.
*
* Returns -ENODEV if the firmware has no event log or securityfs is not
* supported.
*/
int tpm_bios_log_setup(struct tpm_chip *chip)
{
const char *name = dev_name(&chip->dev);
unsigned int cnt;
int log_version;
int rc = 0;
rc = tpm_read_log(chip);
if (rc < 0)
return rc;
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 0;
err:
rc = PTR_ERR(chip->bios_dir[cnt]);
chip->bios_dir[cnt] = NULL;
tpm_bios_log_teardown(chip);
return rc;
}
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]);
}
}
}
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