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/*
* GRUB -- GRand Unified Bootloader
* Copyright (C) 2018 Free Software Foundation, Inc.
*
* GRUB 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 3 of the License, or
* (at your option) any later version.
*
* GRUB is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with GRUB. If not, see <http://www.gnu.org/licenses/>.
*
* EFI TPM support code.
*/
#include <grub/err.h>
#include <grub/i18n.h>
#include <grub/efi/api.h>
#include <grub/efi/efi.h>
#include <grub/efi/tpm.h>
#include <grub/mm.h>
#include <grub/tpm.h>
#include <grub/term.h>
typedef TCG_PCR_EVENT grub_tpm_event_t;
static grub_efi_guid_t tpm_guid = EFI_TPM_GUID;
static grub_efi_guid_t tpm2_guid = EFI_TPM2_GUID;
static grub_efi_handle_t *grub_tpm_handle;
static grub_uint8_t grub_tpm_version;
static grub_int8_t tpm1_present = -1;
static grub_int8_t tpm2_present = -1;
static grub_efi_boolean_t
grub_tpm1_present (grub_efi_tpm_protocol_t *tpm)
{
grub_efi_status_t status;
TCG_EFI_BOOT_SERVICE_CAPABILITY caps;
grub_uint32_t flags;
grub_efi_physical_address_t eventlog, lastevent;
if (tpm1_present != -1)
return (grub_efi_boolean_t) tpm1_present;
caps.Size = (grub_uint8_t) sizeof (caps);
status = efi_call_5 (tpm->status_check, tpm, &caps, &flags, &eventlog,
&lastevent);
if (status != GRUB_EFI_SUCCESS || caps.TPMDeactivatedFlag
|| !caps.TPMPresentFlag)
tpm1_present = 0;
else
tpm1_present = 1;
grub_dprintf ("tpm", "tpm1%s present\n", tpm1_present ? "" : " NOT");
return (grub_efi_boolean_t) tpm1_present;
}
static grub_efi_boolean_t
grub_tpm2_present (grub_efi_tpm2_protocol_t *tpm)
{
grub_efi_status_t status;
EFI_TCG2_BOOT_SERVICE_CAPABILITY caps;
caps.Size = (grub_uint8_t) sizeof (caps);
if (tpm2_present != -1)
return (grub_efi_boolean_t) tpm2_present;
status = efi_call_2 (tpm->get_capability, tpm, &caps);
if (status != GRUB_EFI_SUCCESS || !caps.TPMPresentFlag)
tpm2_present = 0;
else
tpm2_present = 1;
grub_dprintf ("tpm", "tpm2%s present\n", tpm2_present ? "" : " NOT");
return (grub_efi_boolean_t) tpm2_present;
}
static grub_efi_boolean_t
grub_tpm_handle_find (grub_efi_handle_t *tpm_handle,
grub_efi_uint8_t *protocol_version)
{
grub_efi_handle_t *handles;
grub_efi_uintn_t num_handles;
if (grub_tpm_handle != NULL)
{
*tpm_handle = grub_tpm_handle;
*protocol_version = grub_tpm_version;
return 1;
}
handles = grub_efi_locate_handle (GRUB_EFI_BY_PROTOCOL, &tpm_guid, NULL,
&num_handles);
if (handles && num_handles > 0)
{
grub_tpm_handle = handles[0];
*tpm_handle = handles[0];
grub_tpm_version = 1;
*protocol_version = 1;
grub_dprintf ("tpm", "TPM handle Found, version: 1\n");
return 1;
}
handles = grub_efi_locate_handle (GRUB_EFI_BY_PROTOCOL, &tpm2_guid, NULL,
&num_handles);
if (handles && num_handles > 0)
{
grub_tpm_handle = handles[0];
*tpm_handle = handles[0];
grub_tpm_version = 2;
*protocol_version = 2;
grub_dprintf ("tpm", "TPM handle Found, version: 2\n");
return 1;
}
return 0;
}
static grub_err_t
grub_efi_log_event_status (grub_efi_status_t status)
{
switch (status)
{
case GRUB_EFI_SUCCESS:
return 0;
case GRUB_EFI_DEVICE_ERROR:
return grub_error (GRUB_ERR_IO, N_("Command failed"));
case GRUB_EFI_INVALID_PARAMETER:
return grub_error (GRUB_ERR_BAD_ARGUMENT, N_("Invalid parameter"));
case GRUB_EFI_BUFFER_TOO_SMALL:
return grub_error (GRUB_ERR_BAD_ARGUMENT, N_("Output buffer too small"));
case GRUB_EFI_NOT_FOUND:
return grub_error (GRUB_ERR_UNKNOWN_DEVICE, N_("TPM unavailable"));
default:
return grub_error (GRUB_ERR_UNKNOWN_DEVICE, N_("Unknown TPM error"));
}
}
static grub_err_t
grub_tpm1_log_event (grub_efi_handle_t tpm_handle, unsigned char *buf,
grub_size_t size, grub_uint8_t pcr,
const char *description)
{
grub_tpm_event_t *event;
grub_efi_status_t status;
grub_efi_tpm_protocol_t *tpm;
grub_efi_physical_address_t lastevent;
grub_uint32_t algorithm;
grub_uint32_t eventnum = 0;
tpm = grub_efi_open_protocol (tpm_handle, &tpm_guid,
GRUB_EFI_OPEN_PROTOCOL_GET_PROTOCOL);
if (!grub_tpm1_present (tpm))
return 0;
event = grub_zalloc (sizeof (*event) + grub_strlen (description) + 1);
if (!event)
return grub_error (GRUB_ERR_OUT_OF_MEMORY,
N_("cannot allocate TPM event buffer"));
event->PCRIndex = pcr;
event->EventType = EV_IPL;
event->EventSize = grub_strlen (description) + 1;
grub_memcpy (event->Event, description, event->EventSize);
algorithm = TCG_ALG_SHA;
status = efi_call_7 (tpm->log_extend_event, tpm, (grub_addr_t) buf, (grub_uint64_t) size,
algorithm, event, &eventnum, &lastevent);
grub_free (event);
return grub_efi_log_event_status (status);
}
static grub_err_t
grub_tpm2_log_event (grub_efi_handle_t tpm_handle, unsigned char *buf,
grub_size_t size, grub_uint8_t pcr,
const char *description)
{
EFI_TCG2_EVENT *event;
grub_efi_status_t status;
grub_efi_tpm2_protocol_t *tpm;
tpm = grub_efi_open_protocol (tpm_handle, &tpm2_guid,
GRUB_EFI_OPEN_PROTOCOL_GET_PROTOCOL);
if (!grub_tpm2_present (tpm))
return 0;
event =
grub_zalloc (sizeof (EFI_TCG2_EVENT) + grub_strlen (description) + 1);
if (!event)
return grub_error (GRUB_ERR_OUT_OF_MEMORY,
N_("cannot allocate TPM event buffer"));
event->Header.HeaderSize = sizeof (EFI_TCG2_EVENT_HEADER);
event->Header.HeaderVersion = 1;
event->Header.PCRIndex = pcr;
event->Header.EventType = EV_IPL;
event->Size =
sizeof (*event) - sizeof (event->Event) + grub_strlen (description) + 1;
grub_memcpy (event->Event, description, grub_strlen (description) + 1);
status = efi_call_5 (tpm->hash_log_extend_event, tpm, 0, (grub_addr_t) buf,
(grub_uint64_t) size, event);
grub_free (event);
return grub_efi_log_event_status (status);
}
grub_err_t
grub_tpm_measure (unsigned char *buf, grub_size_t size, grub_uint8_t pcr,
const char *description)
{
grub_efi_handle_t tpm_handle;
grub_efi_uint8_t protocol_version;
if (!grub_tpm_handle_find (&tpm_handle, &protocol_version))
return 0;
grub_dprintf ("tpm", "log_event, pcr = %d, size = 0x%" PRIxGRUB_SIZE ", %s\n",
pcr, size, description);
if (protocol_version == 1)
return grub_tpm1_log_event (tpm_handle, buf, size, pcr, description);
else
return grub_tpm2_log_event (tpm_handle, buf, size, pcr, description);
}
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