diff options
Diffstat (limited to 'drivers/char/tpm/eventlog/common.c')
| -rw-r--r-- | drivers/char/tpm/eventlog/common.c | 189 |
1 files changed, 189 insertions, 0 deletions
diff --git a/drivers/char/tpm/eventlog/common.c b/drivers/char/tpm/eventlog/common.c new file mode 100644 index 000000000..8512ec76d --- /dev/null +++ b/drivers/char/tpm/eventlog/common.c @@ -0,0 +1,189 @@ +// 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. + */ +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]); + } + } +} |