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1// SPDX-License-Identifier: GPL-2.0-or-later2/*3 * Copyright (C) 2005, 2012 IBM Corporation4 *5 * Authors:6 * Kent Yoder <key@linux.vnet.ibm.com>7 * Seiji Munetoh <munetoh@jp.ibm.com>8 * Stefan Berger <stefanb@us.ibm.com>9 * Reiner Sailer <sailer@watson.ibm.com>10 * Kylene Hall <kjhall@us.ibm.com>11 * Nayna Jain <nayna@linux.vnet.ibm.com>12 *13 * Access to the event log created by a system's firmware / BIOS14 */15 16#include <linux/seq_file.h>17#include <linux/fs.h>18#include <linux/security.h>19#include <linux/module.h>20#include <linux/tpm_eventlog.h>21 22#include "../tpm.h"23#include "common.h"24 25static int tpm_bios_measurements_open(struct inode *inode,26 struct file *file)27{28 int err;29 struct seq_file *seq;30 struct tpm_chip_seqops *chip_seqops;31 const struct seq_operations *seqops;32 struct tpm_chip *chip;33 34 inode_lock(inode);35 if (!inode->i_private) {36 inode_unlock(inode);37 return -ENODEV;38 }39 chip_seqops = inode->i_private;40 seqops = chip_seqops->seqops;41 chip = chip_seqops->chip;42 get_device(&chip->dev);43 inode_unlock(inode);44 45 /* now register seq file */46 err = seq_open(file, seqops);47 if (!err) {48 seq = file->private_data;49 seq->private = chip;50 } else {51 put_device(&chip->dev);52 }53 54 return err;55}56 57static int tpm_bios_measurements_release(struct inode *inode,58 struct file *file)59{60 struct seq_file *seq = file->private_data;61 struct tpm_chip *chip = seq->private;62 63 put_device(&chip->dev);64 65 return seq_release(inode, file);66}67 68static const struct file_operations tpm_bios_measurements_ops = {69 .owner = THIS_MODULE,70 .open = tpm_bios_measurements_open,71 .read = seq_read,72 .llseek = seq_lseek,73 .release = tpm_bios_measurements_release,74};75 76static int tpm_read_log(struct tpm_chip *chip)77{78 int rc;79 80 if (chip->log.bios_event_log != NULL) {81 dev_dbg(&chip->dev,82 "%s: ERROR - event log already initialized\n",83 __func__);84 return -EFAULT;85 }86 87 rc = tpm_read_log_acpi(chip);88 if (rc != -ENODEV)89 return rc;90 91 rc = tpm_read_log_efi(chip);92 if (rc != -ENODEV)93 return rc;94 95 return tpm_read_log_of(chip);96}97 98/*99 * tpm_bios_log_setup() - Read the event log from the firmware100 * @chip: TPM chip to use.101 *102 * If an event log is found then the securityfs files are setup to103 * export it to userspace, otherwise nothing is done.104 */105void tpm_bios_log_setup(struct tpm_chip *chip)106{107 const char *name = dev_name(&chip->dev);108 unsigned int cnt;109 int log_version;110 int rc = 0;111 112 if (chip->flags & TPM_CHIP_FLAG_VIRTUAL)113 return;114 115 rc = tpm_read_log(chip);116 if (rc < 0)117 return;118 log_version = rc;119 120 cnt = 0;121 chip->bios_dir[cnt] = securityfs_create_dir(name, NULL);122 /* NOTE: securityfs_create_dir can return ENODEV if securityfs is123 * compiled out. The caller should ignore the ENODEV return code.124 */125 if (IS_ERR(chip->bios_dir[cnt]))126 goto err;127 cnt++;128 129 chip->bin_log_seqops.chip = chip;130 if (log_version == EFI_TCG2_EVENT_LOG_FORMAT_TCG_2)131 chip->bin_log_seqops.seqops =132 &tpm2_binary_b_measurements_seqops;133 else134 chip->bin_log_seqops.seqops =135 &tpm1_binary_b_measurements_seqops;136 137 138 chip->bios_dir[cnt] =139 securityfs_create_file("binary_bios_measurements",140 0440, chip->bios_dir[0],141 (void *)&chip->bin_log_seqops,142 &tpm_bios_measurements_ops);143 if (IS_ERR(chip->bios_dir[cnt]))144 goto err;145 cnt++;146 147 if (!(chip->flags & TPM_CHIP_FLAG_TPM2)) {148 149 chip->ascii_log_seqops.chip = chip;150 chip->ascii_log_seqops.seqops =151 &tpm1_ascii_b_measurements_seqops;152 153 chip->bios_dir[cnt] =154 securityfs_create_file("ascii_bios_measurements",155 0440, chip->bios_dir[0],156 (void *)&chip->ascii_log_seqops,157 &tpm_bios_measurements_ops);158 if (IS_ERR(chip->bios_dir[cnt]))159 goto err;160 cnt++;161 }162 163 return;164 165err:166 chip->bios_dir[cnt] = NULL;167 tpm_bios_log_teardown(chip);168 return;169}170 171void tpm_bios_log_teardown(struct tpm_chip *chip)172{173 int i;174 struct inode *inode;175 176 /* securityfs_remove currently doesn't take care of handling sync177 * between removal and opening of pseudo files. To handle this, a178 * workaround is added by making i_private = NULL here during removal179 * and to check it during open(), both within inode_lock()/unlock().180 * This design ensures that open() either safely gets kref or fails.181 */182 for (i = (TPM_NUM_EVENT_LOG_FILES - 1); i >= 0; i--) {183 if (chip->bios_dir[i]) {184 inode = d_inode(chip->bios_dir[i]);185 inode_lock(inode);186 inode->i_private = NULL;187 inode_unlock(inode);188 securityfs_remove(chip->bios_dir[i]);189 }190 }191}192