u-boot/drivers/tpm/tpm_tis_sandbox.c

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/*
* Copyright (c) 2013 Google, Inc
*
* SPDX-License-Identifier: GPL-2.0+
*/
#include <common.h>
#include <dm.h>
#include <tpm.h>
#include <asm/state.h>
#include <asm/unaligned.h>
#include <linux/crc8.h>
/* TPM NVRAM location indices. */
#define FIRMWARE_NV_INDEX 0x1007
#define KERNEL_NV_INDEX 0x1008
#define NV_DATA_PUBLIC_PERMISSIONS_OFFSET 60
/* Kernel TPM space - KERNEL_NV_INDEX, locked with physical presence */
#define ROLLBACK_SPACE_KERNEL_VERSION 2
#define ROLLBACK_SPACE_KERNEL_UID 0x4752574C /* 'GRWL' */
struct rollback_space_kernel {
/* Struct version, for backwards compatibility */
uint8_t struct_version;
/* Unique ID to detect space redefinition */
uint32_t uid;
/* Kernel versions */
uint32_t kernel_versions;
/* Reserved for future expansion */
uint8_t reserved[3];
/* Checksum (v2 and later only) */
uint8_t crc8;
} __packed rollback_space_kernel;
/*
* These numbers derive from adding the sizes of command fields as shown in
* the TPM commands manual.
*/
#define TPM_REQUEST_HEADER_LENGTH 10
#define TPM_RESPONSE_HEADER_LENGTH 10
/* These are the different non-volatile spaces that we emulate */
enum {
NV_GLOBAL_LOCK,
NV_SEQ_FIRMWARE,
NV_SEQ_KERNEL,
NV_SEQ_COUNT,
};
/* Size of each non-volatile space */
#define NV_DATA_SIZE 0x20
/*
* Information about our TPM emulation. This is preserved in the sandbox
* state file if enabled.
*/
static struct tpm_state {
uint8_t nvdata[NV_SEQ_COUNT][NV_DATA_SIZE];
} g_state;
/**
* sandbox_tpm_read_state() - read the sandbox EC state from the state file
*
* If data is available, then blob and node will provide access to it. If
* not this function sets up an empty TPM.
*
* @blob: Pointer to device tree blob, or NULL if no data to read
* @node: Node offset to read from
*/
static int sandbox_tpm_read_state(const void *blob, int node)
{
const char *prop;
int len;
int i;
if (!blob)
return 0;
for (i = 0; i < NV_SEQ_COUNT; i++) {
char prop_name[20];
sprintf(prop_name, "nvdata%d", i);
prop = fdt_getprop(blob, node, prop_name, &len);
if (prop && len == NV_DATA_SIZE)
memcpy(g_state.nvdata[i], prop, NV_DATA_SIZE);
}
return 0;
}
/**
* cros_ec_write_state() - Write out our state to the state file
*
* The caller will ensure that there is a node ready for the state. The node
* may already contain the old state, in which case it is overridden.
*
* @blob: Device tree blob holding state
* @node: Node to write our state into
*/
static int sandbox_tpm_write_state(void *blob, int node)
{
int i;
/*
* We are guaranteed enough space to write basic properties.
* We could use fdt_add_subnode() to put each set of data in its
* own node - perhaps useful if we add access informaiton to each.
*/
for (i = 0; i < NV_SEQ_COUNT; i++) {
char prop_name[20];
sprintf(prop_name, "nvdata%d", i);
fdt_setprop(blob, node, prop_name, g_state.nvdata[i],
NV_DATA_SIZE);
}
return 0;
}
SANDBOX_STATE_IO(sandbox_tpm, "google,sandbox-tpm", sandbox_tpm_read_state,
sandbox_tpm_write_state);
static int index_to_seq(uint32_t index)
{
switch (index) {
case FIRMWARE_NV_INDEX:
return NV_SEQ_FIRMWARE;
case KERNEL_NV_INDEX:
return NV_SEQ_KERNEL;
case 0:
return NV_GLOBAL_LOCK;
}
printf("Invalid nv index %#x\n", index);
return -1;
}
static int sandbox_tpm_xfer(struct udevice *dev, const uint8_t *sendbuf,
size_t send_size, uint8_t *recvbuf,
size_t *recv_len)
{
struct tpm_state *tpm = dev_get_priv(dev);
uint32_t code, index, length, type;
uint8_t *data;
int seq;
code = get_unaligned_be32(sendbuf + sizeof(uint16_t) +
sizeof(uint32_t));
printf("tpm: %zd bytes, recv_len %zd, cmd = %x\n", send_size,
*recv_len, code);
print_buffer(0, sendbuf, 1, send_size, 0);
switch (code) {
case 0x65: /* get flags */
type = get_unaligned_be32(sendbuf + 14);
switch (type) {
case 4:
index = get_unaligned_be32(sendbuf + 18);
printf("Get flags index %#02x\n", index);
*recv_len = 22;
memset(recvbuf, '\0', *recv_len);
put_unaligned_be32(22, recvbuf +
TPM_RESPONSE_HEADER_LENGTH);
data = recvbuf + TPM_RESPONSE_HEADER_LENGTH +
sizeof(uint32_t);
switch (index) {
case FIRMWARE_NV_INDEX:
break;
case KERNEL_NV_INDEX:
/* TPM_NV_PER_PPWRITE */
put_unaligned_be32(1, data +
NV_DATA_PUBLIC_PERMISSIONS_OFFSET);
break;
}
break;
case 0x11: /* TPM_CAP_NV_INDEX */
index = get_unaligned_be32(sendbuf + 18);
printf("Get cap nv index %#02x\n", index);
put_unaligned_be32(22, recvbuf +
TPM_RESPONSE_HEADER_LENGTH);
break;
default:
printf(" ** Unknown 0x65 command type %#02x\n",
type);
return -1;
}
break;
case 0xcd: /* nvwrite */
index = get_unaligned_be32(sendbuf + 10);
length = get_unaligned_be32(sendbuf + 18);
seq = index_to_seq(index);
if (seq < 0)
return -1;
printf("tpm: nvwrite index=%#02x, len=%#02x\n", index, length);
memcpy(&tpm->nvdata[seq], sendbuf + 22, length);
*recv_len = 12;
memset(recvbuf, '\0', *recv_len);
break;
case 0xcf: /* nvread */
index = get_unaligned_be32(sendbuf + 10);
length = get_unaligned_be32(sendbuf + 18);
seq = index_to_seq(index);
if (seq < 0)
return -1;
printf("tpm: nvread index=%#02x, len=%#02x\n", index, length);
*recv_len = TPM_RESPONSE_HEADER_LENGTH + sizeof(uint32_t) +
length;
memset(recvbuf, '\0', *recv_len);
put_unaligned_be32(length, recvbuf +
TPM_RESPONSE_HEADER_LENGTH);
if (seq == NV_SEQ_KERNEL) {
struct rollback_space_kernel rsk;
data = recvbuf + TPM_RESPONSE_HEADER_LENGTH +
sizeof(uint32_t);
rsk.struct_version = 2;
rsk.uid = ROLLBACK_SPACE_KERNEL_UID;
rsk.kernel_versions = 0;
rsk.crc8 = crc8((unsigned char *)&rsk,
offsetof(struct rollback_space_kernel,
crc8));
memcpy(data, &rsk, sizeof(rsk));
} else {
memcpy(recvbuf + TPM_RESPONSE_HEADER_LENGTH +
sizeof(uint32_t), &tpm->nvdata[seq], length);
}
break;
case 0x14: /* tpm extend */
case 0x15: /* pcr read */
case 0x5d: /* force clear */
case 0x6f: /* physical enable */
case 0x72: /* physical set deactivated */
case 0x99: /* startup */
case 0x4000000a: /* assert physical presence */
*recv_len = 12;
memset(recvbuf, '\0', *recv_len);
break;
default:
printf("Unknown tpm command %02x\n", code);
return -1;
}
return 0;
}
static int sandbox_tpm_get_desc(struct udevice *dev, char *buf, int size)
{
if (size < 15)
return -ENOSPC;
return snprintf(buf, size, "sandbox TPM");
}
static int sandbox_tpm_probe(struct udevice *dev)
{
struct tpm_state *tpm = dev_get_priv(dev);
memcpy(tpm, &g_state, sizeof(*tpm));
return 0;
}
static int sandbox_tpm_open(struct udevice *dev)
{
return 0;
}
static int sandbox_tpm_close(struct udevice *dev)
{
return 0;
}
static const struct tpm_ops sandbox_tpm_ops = {
.open = sandbox_tpm_open,
.close = sandbox_tpm_close,
.get_desc = sandbox_tpm_get_desc,
.xfer = sandbox_tpm_xfer,
};
static const struct udevice_id sandbox_tpm_ids[] = {
{ .compatible = "google,sandbox-tpm" },
{ }
};
U_BOOT_DRIVER(sandbox_tpm) = {
.name = "sandbox_tpm",
.id = UCLASS_TPM,
.of_match = sandbox_tpm_ids,
.ops = &sandbox_tpm_ops,
.probe = sandbox_tpm_probe,
.priv_auto_alloc_size = sizeof(struct tpm_state),
};