blob: b11d6a3d163643ec1328c5dfb8f359b6936c1780 [file] [log] [blame]
/* Copyright (c) 2012 The Chromium OS Authors. All rights reserved.
* Use of this source code is governed by a BSD-style license that can be
* found in the LICENSE file.
*/
/* A lightweight TPM command library.
*
* The general idea is that TPM commands are array of bytes whose
* fields are mostly compile-time constant. The goal is to build much
* of the commands at compile time (or build time) and change some of
* the fields at run time as needed. The code in
* utility/tlcl_generator.c builds structures containing the commands,
* as well as the offsets of the fields that need to be set at run
* time.
*/
#include <arch/early_variables.h>
#include <assert.h>
#include <string.h>
#include <security/tpm/tis.h>
#include <vb2_api.h>
#include <security/tpm/tss.h>
#include "tss_internal.h"
#include "tss_commands.h"
#ifdef FOR_TEST
#include <stdio.h>
#define VBDEBUG(format, args...) printf(format, ## args)
#else
#include <console/console.h>
#define VBDEBUG(format, args...) printk(BIOS_DEBUG, format, ## args)
#endif
static int tpm_send_receive(const uint8_t *request,
uint32_t request_length,
uint8_t *response,
uint32_t *response_length)
{
size_t len = *response_length;
if (tis_sendrecv(request, request_length, response, &len))
return VB2_ERROR_UNKNOWN;
/* check 64->32bit overflow and (re)check response buffer overflow */
if (len > *response_length)
return VB2_ERROR_UNKNOWN;
*response_length = len;
return VB2_SUCCESS;
}
/* Sets the size field of a TPM command. */
static inline void set_tpm_command_size(uint8_t *buffer, uint32_t size)
{
to_tpm_uint32(buffer + sizeof(uint16_t), size);
}
/* Gets the size field of a TPM command. */
__attribute__((unused))
static inline int tpm_command_size(const uint8_t *buffer)
{
uint32_t size;
from_tpm_uint32(buffer + sizeof(uint16_t), &size);
return (int) size;
}
/* Gets the code field of a TPM command. */
static inline int tpm_command_code(const uint8_t *buffer)
{
uint32_t code;
from_tpm_uint32(buffer + sizeof(uint16_t) + sizeof(uint32_t), &code);
return code;
}
/* Gets the return code field of a TPM result. */
static inline int tpm_return_code(const uint8_t *buffer)
{
return tpm_command_code(buffer);
}
/* Like TlclSendReceive below, but do not retry if NEEDS_SELFTEST or
* DOING_SELFTEST errors are returned.
*/
static uint32_t tlcl_send_receive_no_retry(const uint8_t *request,
uint8_t *response, int max_length)
{
uint32_t response_length = max_length;
uint32_t result;
result = tpm_send_receive(request, tpm_command_size(request),
response, &response_length);
if (result != 0) {
/* Communication with TPM failed, so response is garbage */
VBDEBUG("TPM: command 0x%x send/receive failed: 0x%x\n",
tpm_command_code(request), result);
return result;
}
/* Otherwise, use the result code from the response */
result = tpm_return_code(response);
/* TODO: add paranoia about returned response_length vs. max_length
* (and possibly expected length from the response header). See
* crosbug.com/17017 */
VBDEBUG("TPM: command 0x%x returned 0x%x\n",
tpm_command_code(request), result);
return result;
}
/* Sends a TPM command and gets a response. Returns 0 if success or the TPM
* error code if error. Waits for the self test to complete if needed. */
uint32_t tlcl_send_receive(const uint8_t *request, uint8_t *response,
int max_length)
{
uint32_t result = tlcl_send_receive_no_retry(request, response,
max_length);
/* If the command fails because the self test has not completed, try it
* again after attempting to ensure that the self test has completed. */
if (result == TPM_E_NEEDS_SELFTEST || result == TPM_E_DOING_SELFTEST) {
result = tlcl_continue_self_test();
if (result != TPM_SUCCESS)
return result;
#if defined(TPM_BLOCKING_CONTINUESELFTEST) || defined(VB_RECOVERY_MODE)
/* Retry only once */
result = tlcl_send_receive_no_retry(request, response,
max_length);
#else
/* This needs serious testing. The TPM specification says: "iii.
* The caller MUST wait for the actions of TPM_ContinueSelfTest
* to complete before reissuing the command C1." But, if
* ContinueSelfTest is non-blocking, how do we know that the
* actions have completed other than trying again? */
do {
result = tlcl_send_receive_no_retry(request, response,
max_length);
} while (result == TPM_E_DOING_SELFTEST);
#endif
}
return result;
}
/* Sends a command and returns the error code. */
static uint32_t send(const uint8_t *command)
{
uint8_t response[TPM_LARGE_ENOUGH_COMMAND_SIZE];
return tlcl_send_receive(command, response, sizeof(response));
}
/* Exported functions. */
static uint8_t tlcl_init_done CAR_GLOBAL;
uint32_t tlcl_lib_init(void)
{
uint8_t done = car_get_var(tlcl_init_done);
if (done)
return VB2_SUCCESS;
if (tis_init())
return VB2_ERROR_UNKNOWN;
if (tis_open())
return VB2_ERROR_UNKNOWN;
car_set_var(tlcl_init_done, 1);
return VB2_SUCCESS;
}
uint32_t tlcl_startup(void)
{
VBDEBUG("TPM: Startup\n");
return send(tpm_startup_cmd.buffer);
}
uint32_t tlcl_resume(void)
{
VBDEBUG("TPM: Resume\n");
return send(tpm_resume_cmd.buffer);
}
uint32_t tlcl_save_state(void)
{
VBDEBUG("TPM: Save state\n");
return send(tpm_savestate_cmd.buffer);
}
uint32_t tlcl_self_test_full(void)
{
VBDEBUG("TPM: Self test full\n");
return send(tpm_selftestfull_cmd.buffer);
}
uint32_t tlcl_continue_self_test(void)
{
uint8_t response[TPM_LARGE_ENOUGH_COMMAND_SIZE];
VBDEBUG("TPM: Continue self test\n");
/* Call the No Retry version of SendReceive to avoid recursion. */
return tlcl_send_receive_no_retry(tpm_continueselftest_cmd.buffer,
response, sizeof(response));
}
uint32_t tlcl_define_space(uint32_t index, uint32_t perm, uint32_t size)
{
struct s_tpm_nv_definespace_cmd cmd;
VBDEBUG("TPM: TlclDefineSpace(0x%x, 0x%x, %d)\n", index, perm, size);
memcpy(&cmd, &tpm_nv_definespace_cmd, sizeof(cmd));
to_tpm_uint32(cmd.buffer + tpm_nv_definespace_cmd.index, index);
to_tpm_uint32(cmd.buffer + tpm_nv_definespace_cmd.perm, perm);
to_tpm_uint32(cmd.buffer + tpm_nv_definespace_cmd.size, size);
return send(cmd.buffer);
}
uint32_t tlcl_write(uint32_t index, const void *data, uint32_t length)
{
struct s_tpm_nv_write_cmd cmd;
uint8_t response[TPM_LARGE_ENOUGH_COMMAND_SIZE];
const int total_length =
kTpmRequestHeaderLength + kWriteInfoLength + length;
VBDEBUG("TPM: tlcl_write(0x%x, %d)\n", index, length);
memcpy(&cmd, &tpm_nv_write_cmd, sizeof(cmd));
assert(total_length <= TPM_LARGE_ENOUGH_COMMAND_SIZE);
set_tpm_command_size(cmd.buffer, total_length);
to_tpm_uint32(cmd.buffer + tpm_nv_write_cmd.index, index);
to_tpm_uint32(cmd.buffer + tpm_nv_write_cmd.length, length);
memcpy(cmd.buffer + tpm_nv_write_cmd.data, data, length);
return tlcl_send_receive(cmd.buffer, response, sizeof(response));
}
uint32_t tlcl_read(uint32_t index, void *data, uint32_t length)
{
struct s_tpm_nv_read_cmd cmd;
uint8_t response[TPM_LARGE_ENOUGH_COMMAND_SIZE];
uint32_t result_length;
uint32_t result;
VBDEBUG("TPM: tlcl_read(0x%x, %d)\n", index, length);
memcpy(&cmd, &tpm_nv_read_cmd, sizeof(cmd));
to_tpm_uint32(cmd.buffer + tpm_nv_read_cmd.index, index);
to_tpm_uint32(cmd.buffer + tpm_nv_read_cmd.length, length);
result = tlcl_send_receive(cmd.buffer, response, sizeof(response));
if (result == TPM_SUCCESS && length > 0) {
uint8_t *nv_read_cursor = response + kTpmResponseHeaderLength;
from_tpm_uint32(nv_read_cursor, &result_length);
if (result_length > length)
return TPM_E_IOERROR;
nv_read_cursor += sizeof(uint32_t);
memcpy(data, nv_read_cursor, result_length);
}
return result;
}
uint32_t tlcl_assert_physical_presence(void)
{
VBDEBUG("TPM: Asserting physical presence\n");
return send(tpm_ppassert_cmd.buffer);
}
uint32_t tlcl_physical_presence_cmd_enable(void)
{
VBDEBUG("TPM: Enable the physical presence command\n");
return send(tpm_ppenable_cmd.buffer);
}
uint32_t tlcl_finalize_physical_presence(void)
{
VBDEBUG("TPM: Enable PP cmd, disable HW pp, and set lifetime lock\n");
return send(tpm_finalizepp_cmd.buffer);
}
uint32_t tlcl_set_nv_locked(void)
{
VBDEBUG("TPM: Set NV locked\n");
return tlcl_define_space(TPM_NV_INDEX_LOCK, 0, 0);
}
uint32_t tlcl_force_clear(void)
{
VBDEBUG("TPM: Force clear\n");
return send(tpm_forceclear_cmd.buffer);
}
uint32_t tlcl_set_enable(void)
{
VBDEBUG("TPM: Enabling TPM\n");
return send(tpm_physicalenable_cmd.buffer);
}
uint32_t tlcl_set_deactivated(uint8_t flag)
{
struct s_tpm_physicalsetdeactivated_cmd cmd;
VBDEBUG("TPM: SetDeactivated(%d)\n", flag);
memcpy(&cmd, &tpm_physicalsetdeactivated_cmd, sizeof(cmd));
*(cmd.buffer + cmd.deactivated) = flag;
return send(cmd.buffer);
}
uint32_t tlcl_get_permanent_flags(TPM_PERMANENT_FLAGS *pflags)
{
uint8_t response[TPM_LARGE_ENOUGH_COMMAND_SIZE];
uint32_t size;
uint32_t result = tlcl_send_receive(tpm_getflags_cmd.buffer, response,
sizeof(response));
if (result != TPM_SUCCESS)
return result;
from_tpm_uint32(response + kTpmResponseHeaderLength, &size);
if (size != sizeof(TPM_PERMANENT_FLAGS))
return TPM_E_IOERROR;
memcpy(pflags, response + kTpmResponseHeaderLength + sizeof(size),
sizeof(TPM_PERMANENT_FLAGS));
return result;
}
uint32_t tlcl_get_flags(uint8_t *disable, uint8_t *deactivated,
uint8_t *nvlocked)
{
TPM_PERMANENT_FLAGS pflags;
uint32_t result = tlcl_get_permanent_flags(&pflags);
if (result == TPM_SUCCESS) {
if (disable)
*disable = pflags.disable;
if (deactivated)
*deactivated = pflags.deactivated;
if (nvlocked)
*nvlocked = pflags.nvLocked;
VBDEBUG("TPM: flags disable=%d, deactivated=%d, nvlocked=%d\n",
pflags.disable, pflags.deactivated, pflags.nvLocked);
}
return result;
}
uint32_t tlcl_set_global_lock(void)
{
uint32_t x;
VBDEBUG("TPM: Set global lock\n");
return tlcl_write(TPM_NV_INDEX0, (uint8_t *) &x, 0);
}
uint32_t tlcl_extend(int pcr_num, const uint8_t *in_digest,
uint8_t *out_digest)
{
struct s_tpm_extend_cmd cmd;
uint8_t response[kTpmResponseHeaderLength + kPcrDigestLength];
uint32_t result;
memcpy(&cmd, &tpm_extend_cmd, sizeof(cmd));
to_tpm_uint32(cmd.buffer + tpm_extend_cmd.pcrNum, pcr_num);
memcpy(cmd.buffer + cmd.inDigest, in_digest, kPcrDigestLength);
result = tlcl_send_receive(cmd.buffer, response, sizeof(response));
if (result != TPM_SUCCESS)
return result;
if (out_digest)
memcpy(out_digest, response + kTpmResponseHeaderLength,
kPcrDigestLength);
return result;
}