linux-zen-desktop/drivers/char/tpm/eventlog/efi.c

126 lines
3.0 KiB
C

// SPDX-License-Identifier: GPL-2.0-or-later
/*
* Copyright (C) 2017 Google
*
* Authors:
* Thiebaud Weksteen <tweek@google.com>
*/
#include <linux/device.h>
#include <linux/efi.h>
#include <linux/tpm_eventlog.h>
#include "../tpm.h"
#include "common.h"
/* read binary bios log from EFI configuration table */
int tpm_read_log_efi(struct tpm_chip *chip)
{
struct efi_tcg2_final_events_table *final_tbl = NULL;
int final_events_log_size = efi_tpm_final_log_size;
struct linux_efi_tpm_eventlog *log_tbl;
struct tpm_bios_log *log;
u32 log_size;
u8 tpm_log_version;
void *tmp;
int ret;
if (!(chip->flags & TPM_CHIP_FLAG_TPM2))
return -ENODEV;
if (efi.tpm_log == EFI_INVALID_TABLE_ADDR)
return -ENODEV;
log = &chip->log;
log_tbl = memremap(efi.tpm_log, sizeof(*log_tbl), MEMREMAP_WB);
if (!log_tbl) {
pr_err("Could not map UEFI TPM log table !\n");
return -ENOMEM;
}
log_size = log_tbl->size;
memunmap(log_tbl);
if (!log_size) {
pr_warn("UEFI TPM log area empty\n");
return -EIO;
}
log_tbl = memremap(efi.tpm_log, sizeof(*log_tbl) + log_size,
MEMREMAP_WB);
if (!log_tbl) {
pr_err("Could not map UEFI TPM log table payload!\n");
return -ENOMEM;
}
/* malloc EventLog space */
log->bios_event_log = devm_kmemdup(&chip->dev, log_tbl->log, log_size, GFP_KERNEL);
if (!log->bios_event_log) {
ret = -ENOMEM;
goto out;
}
log->bios_event_log_end = log->bios_event_log + log_size;
tpm_log_version = log_tbl->version;
ret = tpm_log_version;
if (efi.tpm_final_log == EFI_INVALID_TABLE_ADDR ||
final_events_log_size == 0 ||
tpm_log_version != EFI_TCG2_EVENT_LOG_FORMAT_TCG_2)
goto out;
final_tbl = memremap(efi.tpm_final_log,
sizeof(*final_tbl) + final_events_log_size,
MEMREMAP_WB);
if (!final_tbl) {
pr_err("Could not map UEFI TPM final log\n");
devm_kfree(&chip->dev, log->bios_event_log);
ret = -ENOMEM;
goto out;
}
/*
* The 'final events log' size excludes the 'final events preboot log'
* at its beginning.
*/
final_events_log_size -= log_tbl->final_events_preboot_size;
/*
* Allocate memory for the 'combined log' where we will append the
* 'final events log' to.
*/
tmp = devm_krealloc(&chip->dev, log->bios_event_log,
log_size + final_events_log_size,
GFP_KERNEL);
if (!tmp) {
devm_kfree(&chip->dev, log->bios_event_log);
ret = -ENOMEM;
goto out;
}
log->bios_event_log = tmp;
/*
* Append any of the 'final events log' that didn't also end up in the
* 'main log'. Events can be logged in both if events are generated
* between GetEventLog() and ExitBootServices().
*/
memcpy((void *)log->bios_event_log + log_size,
final_tbl->events + log_tbl->final_events_preboot_size,
final_events_log_size);
/*
* The size of the 'combined log' is the size of the 'main log' plus
* the size of the 'final events log'.
*/
log->bios_event_log_end = log->bios_event_log +
log_size + final_events_log_size;
out:
memunmap(final_tbl);
memunmap(log_tbl);
return ret;
}