linux/drivers/char/tpm/tpm1_eventlog.c
Thiebaud Weksteen 58cc1e4faf tpm: parse TPM event logs based on EFI table
If we are not able to retrieve the TPM event logs from the ACPI table,
check the EFI configuration table (Linux-specific GUID).

The format version of the log is now returned by the provider function.

Signed-off-by: Thiebaud Weksteen <tweek@google.com>
Reviewed-by: Jason Gunthorpe <jgunthorpe@obsidianresearch.com>
Reviewed-by: Javier Martinez Canillas <javierm@redhat.com>
Tested-by: Javier Martinez Canillas <javierm@redhat.com>
Tested-by: Jarkko Sakkinen  <jarkko.sakkinen@linux.intel.com>
Reviewed-by: Jarkko Sakkinen  <jarkko.sakkinen@linux.intel.com>
Signed-off-by: Jarkko Sakkinen  <jarkko.sakkinen@linux.intel.com>
2018-01-08 12:58:35 +02:00

477 lines
11 KiB
C

/*
* 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>
*
* Maintained by: <tpmdd-devel@lists.sourceforge.net>
*
* Access to the event log created by a system's firmware / BIOS
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version
* 2 of the License, or (at your option) any later version.
*
*/
#include <linux/seq_file.h>
#include <linux/efi.h>
#include <linux/fs.h>
#include <linux/security.h>
#include <linux/module.h>
#include <linux/slab.h>
#include <linux/tpm_eventlog.h>
#include "tpm.h"
static const char* tcpa_event_type_strings[] = {
"PREBOOT",
"POST CODE",
"",
"NO ACTION",
"SEPARATOR",
"ACTION",
"EVENT TAG",
"S-CRTM Contents",
"S-CRTM Version",
"CPU Microcode",
"Platform Config Flags",
"Table of Devices",
"Compact Hash",
"IPL",
"IPL Partition Data",
"Non-Host Code",
"Non-Host Config",
"Non-Host Info"
};
static const char* tcpa_pc_event_id_strings[] = {
"",
"SMBIOS",
"BIS Certificate",
"POST BIOS ",
"ESCD ",
"CMOS",
"NVRAM",
"Option ROM",
"Option ROM config",
"",
"Option ROM microcode ",
"S-CRTM Version",
"S-CRTM Contents ",
"POST Contents ",
"Table of Devices",
};
/* returns pointer to start of pos. entry of tcg log */
static void *tpm_bios_measurements_start(struct seq_file *m, loff_t *pos)
{
loff_t i;
struct tpm_chip *chip = m->private;
struct tpm_bios_log *log = &chip->log;
void *addr = log->bios_event_log;
void *limit = log->bios_event_log_end;
struct tcpa_event *event;
u32 converted_event_size;
u32 converted_event_type;
/* read over *pos measurements */
for (i = 0; i < *pos; i++) {
event = addr;
converted_event_size =
do_endian_conversion(event->event_size);
converted_event_type =
do_endian_conversion(event->event_type);
if ((addr + sizeof(struct tcpa_event)) < limit) {
if ((converted_event_type == 0) &&
(converted_event_size == 0))
return NULL;
addr += (sizeof(struct tcpa_event) +
converted_event_size);
}
}
/* now check if current entry is valid */
if ((addr + sizeof(struct tcpa_event)) >= limit)
return NULL;
event = addr;
converted_event_size = do_endian_conversion(event->event_size);
converted_event_type = do_endian_conversion(event->event_type);
if (((converted_event_type == 0) && (converted_event_size == 0))
|| ((addr + sizeof(struct tcpa_event) + converted_event_size)
>= limit))
return NULL;
return addr;
}
static void *tpm_bios_measurements_next(struct seq_file *m, void *v,
loff_t *pos)
{
struct tcpa_event *event = v;
struct tpm_chip *chip = m->private;
struct tpm_bios_log *log = &chip->log;
void *limit = log->bios_event_log_end;
u32 converted_event_size;
u32 converted_event_type;
converted_event_size = do_endian_conversion(event->event_size);
v += sizeof(struct tcpa_event) + converted_event_size;
/* now check if current entry is valid */
if ((v + sizeof(struct tcpa_event)) >= limit)
return NULL;
event = v;
converted_event_size = do_endian_conversion(event->event_size);
converted_event_type = do_endian_conversion(event->event_type);
if (((converted_event_type == 0) && (converted_event_size == 0)) ||
((v + sizeof(struct tcpa_event) + converted_event_size) >= limit))
return NULL;
(*pos)++;
return v;
}
static void tpm_bios_measurements_stop(struct seq_file *m, void *v)
{
}
static int get_event_name(char *dest, struct tcpa_event *event,
unsigned char * event_entry)
{
const char *name = "";
/* 41 so there is room for 40 data and 1 nul */
char data[41] = "";
int i, n_len = 0, d_len = 0;
struct tcpa_pc_event *pc_event;
switch (do_endian_conversion(event->event_type)) {
case PREBOOT:
case POST_CODE:
case UNUSED:
case NO_ACTION:
case SCRTM_CONTENTS:
case SCRTM_VERSION:
case CPU_MICROCODE:
case PLATFORM_CONFIG_FLAGS:
case TABLE_OF_DEVICES:
case COMPACT_HASH:
case IPL:
case IPL_PARTITION_DATA:
case NONHOST_CODE:
case NONHOST_CONFIG:
case NONHOST_INFO:
name = tcpa_event_type_strings[do_endian_conversion
(event->event_type)];
n_len = strlen(name);
break;
case SEPARATOR:
case ACTION:
if (MAX_TEXT_EVENT >
do_endian_conversion(event->event_size)) {
name = event_entry;
n_len = do_endian_conversion(event->event_size);
}
break;
case EVENT_TAG:
pc_event = (struct tcpa_pc_event *)event_entry;
/* ToDo Row data -> Base64 */
switch (do_endian_conversion(pc_event->event_id)) {
case SMBIOS:
case BIS_CERT:
case CMOS:
case NVRAM:
case OPTION_ROM_EXEC:
case OPTION_ROM_CONFIG:
case S_CRTM_VERSION:
name = tcpa_pc_event_id_strings[do_endian_conversion
(pc_event->event_id)];
n_len = strlen(name);
break;
/* hash data */
case POST_BIOS_ROM:
case ESCD:
case OPTION_ROM_MICROCODE:
case S_CRTM_CONTENTS:
case POST_CONTENTS:
name = tcpa_pc_event_id_strings[do_endian_conversion
(pc_event->event_id)];
n_len = strlen(name);
for (i = 0; i < 20; i++)
d_len += sprintf(&data[2*i], "%02x",
pc_event->event_data[i]);
break;
default:
break;
}
default:
break;
}
return snprintf(dest, MAX_TEXT_EVENT, "[%.*s%.*s]",
n_len, name, d_len, data);
}
static int tpm_binary_bios_measurements_show(struct seq_file *m, void *v)
{
struct tcpa_event *event = v;
struct tcpa_event temp_event;
char *temp_ptr;
int i;
memcpy(&temp_event, event, sizeof(struct tcpa_event));
/* convert raw integers for endianness */
temp_event.pcr_index = do_endian_conversion(event->pcr_index);
temp_event.event_type = do_endian_conversion(event->event_type);
temp_event.event_size = do_endian_conversion(event->event_size);
temp_ptr = (char *) &temp_event;
for (i = 0; i < (sizeof(struct tcpa_event) - 1) ; i++)
seq_putc(m, temp_ptr[i]);
temp_ptr = (char *) v;
for (i = (sizeof(struct tcpa_event) - 1);
i < (sizeof(struct tcpa_event) + temp_event.event_size); i++)
seq_putc(m, temp_ptr[i]);
return 0;
}
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 int tpm_ascii_bios_measurements_show(struct seq_file *m, void *v)
{
int len = 0;
char *eventname;
struct tcpa_event *event = v;
unsigned char *event_entry =
(unsigned char *)(v + sizeof(struct tcpa_event));
eventname = kmalloc(MAX_TEXT_EVENT, GFP_KERNEL);
if (!eventname) {
printk(KERN_ERR "%s: ERROR - No Memory for event name\n ",
__func__);
return -EFAULT;
}
/* 1st: PCR */
seq_printf(m, "%2d ", do_endian_conversion(event->pcr_index));
/* 2nd: SHA1 */
seq_printf(m, "%20phN", event->pcr_value);
/* 3rd: event type identifier */
seq_printf(m, " %02x", do_endian_conversion(event->event_type));
len += get_event_name(eventname, event, event_entry);
/* 4th: eventname <= max + \'0' delimiter */
seq_printf(m, " %s\n", eventname);
kfree(eventname);
return 0;
}
static const struct seq_operations tpm_ascii_b_measurements_seqops = {
.start = tpm_bios_measurements_start,
.next = tpm_bios_measurements_next,
.stop = tpm_bios_measurements_stop,
.show = tpm_ascii_bios_measurements_show,
};
static const struct seq_operations tpm_binary_b_measurements_seqops = {
.start = tpm_bios_measurements_start,
.next = tpm_bios_measurements_next,
.stop = tpm_bios_measurements_stop,
.show = tpm_binary_bios_measurements_show,
};
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 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 =
&tpm_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 =
&tpm_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]);
}
}
}