// 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_nlink) {
                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);
        struct dentry *dentry;
        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;

        chip->bios_dir = 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))
                return;

        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;


        dentry =
            securityfs_create_file("binary_bios_measurements",
                                   0440, chip->bios_dir,
                                   (void *)&chip->bin_log_seqops,
                                   &tpm_bios_measurements_ops);
        if (IS_ERR(dentry))
                goto err;

        if (!(chip->flags & TPM_CHIP_FLAG_TPM2)) {

                chip->ascii_log_seqops.chip = chip;
                chip->ascii_log_seqops.seqops =
                        &tpm1_ascii_b_measurements_seqops;

                dentry =
                        securityfs_create_file("ascii_bios_measurements",
                                               0440, chip->bios_dir,
                                               (void *)&chip->ascii_log_seqops,
                                               &tpm_bios_measurements_ops);
                if (IS_ERR(dentry))
                        goto err;
        }

        return;

err:
        tpm_bios_log_teardown(chip);
        return;
}

void tpm_bios_log_teardown(struct tpm_chip *chip)
{
        securityfs_remove(chip->bios_dir);
}