293 lines
7.2 KiB
C
293 lines
7.2 KiB
C
// SPDX-License-Identifier: GPL-2.0+
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/*
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* Copyright (c) 2013 Google, Inc
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*/
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#include <common.h>
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#include <dm.h>
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#include <tpm-v1.h>
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#include <asm/state.h>
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#include <asm/unaligned.h>
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#include <linux/crc8.h>
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/* TPM NVRAM location indices. */
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#define FIRMWARE_NV_INDEX 0x1007
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#define KERNEL_NV_INDEX 0x1008
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#define NV_DATA_PUBLIC_PERMISSIONS_OFFSET 60
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/* Kernel TPM space - KERNEL_NV_INDEX, locked with physical presence */
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#define ROLLBACK_SPACE_KERNEL_VERSION 2
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#define ROLLBACK_SPACE_KERNEL_UID 0x4752574C /* 'GRWL' */
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struct rollback_space_kernel {
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/* Struct version, for backwards compatibility */
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uint8_t struct_version;
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/* Unique ID to detect space redefinition */
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uint32_t uid;
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/* Kernel versions */
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uint32_t kernel_versions;
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/* Reserved for future expansion */
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uint8_t reserved[3];
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/* Checksum (v2 and later only) */
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uint8_t crc8;
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} __packed rollback_space_kernel;
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/*
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* These numbers derive from adding the sizes of command fields as shown in
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* the TPM commands manual.
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*/
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#define TPM_REQUEST_HEADER_LENGTH 10
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#define TPM_RESPONSE_HEADER_LENGTH 10
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/* These are the different non-volatile spaces that we emulate */
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enum {
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NV_GLOBAL_LOCK,
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NV_SEQ_FIRMWARE,
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NV_SEQ_KERNEL,
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NV_SEQ_COUNT,
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};
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/* Size of each non-volatile space */
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#define NV_DATA_SIZE 0x20
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/*
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* Information about our TPM emulation. This is preserved in the sandbox
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* state file if enabled.
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*/
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static struct tpm_state {
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uint8_t nvdata[NV_SEQ_COUNT][NV_DATA_SIZE];
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} g_state;
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/**
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* sandbox_tpm_read_state() - read the sandbox EC state from the state file
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*
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* If data is available, then blob and node will provide access to it. If
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* not this function sets up an empty TPM.
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*
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* @blob: Pointer to device tree blob, or NULL if no data to read
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* @node: Node offset to read from
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*/
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static int sandbox_tpm_read_state(const void *blob, int node)
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{
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const char *prop;
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int len;
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int i;
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if (!blob)
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return 0;
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for (i = 0; i < NV_SEQ_COUNT; i++) {
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char prop_name[20];
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sprintf(prop_name, "nvdata%d", i);
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prop = fdt_getprop(blob, node, prop_name, &len);
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if (prop && len == NV_DATA_SIZE)
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memcpy(g_state.nvdata[i], prop, NV_DATA_SIZE);
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}
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return 0;
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}
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/**
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* cros_ec_write_state() - Write out our state to the state file
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*
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* The caller will ensure that there is a node ready for the state. The node
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* may already contain the old state, in which case it is overridden.
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*
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* @blob: Device tree blob holding state
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* @node: Node to write our state into
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*/
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static int sandbox_tpm_write_state(void *blob, int node)
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{
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int i;
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/*
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* We are guaranteed enough space to write basic properties.
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* We could use fdt_add_subnode() to put each set of data in its
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* own node - perhaps useful if we add access informaiton to each.
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*/
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for (i = 0; i < NV_SEQ_COUNT; i++) {
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char prop_name[20];
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sprintf(prop_name, "nvdata%d", i);
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fdt_setprop(blob, node, prop_name, g_state.nvdata[i],
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NV_DATA_SIZE);
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}
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return 0;
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}
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SANDBOX_STATE_IO(sandbox_tpm, "google,sandbox-tpm", sandbox_tpm_read_state,
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sandbox_tpm_write_state);
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static int index_to_seq(uint32_t index)
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{
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switch (index) {
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case FIRMWARE_NV_INDEX:
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return NV_SEQ_FIRMWARE;
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case KERNEL_NV_INDEX:
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return NV_SEQ_KERNEL;
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case 0:
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return NV_GLOBAL_LOCK;
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}
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printf("Invalid nv index %#x\n", index);
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return -1;
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}
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static int sandbox_tpm_xfer(struct udevice *dev, const uint8_t *sendbuf,
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size_t send_size, uint8_t *recvbuf,
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size_t *recv_len)
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{
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struct tpm_state *tpm = dev_get_priv(dev);
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uint32_t code, index, length, type;
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uint8_t *data;
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int seq;
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code = get_unaligned_be32(sendbuf + sizeof(uint16_t) +
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sizeof(uint32_t));
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printf("tpm: %zd bytes, recv_len %zd, cmd = %x\n", send_size,
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*recv_len, code);
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print_buffer(0, sendbuf, 1, send_size, 0);
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switch (code) {
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case 0x65: /* get flags */
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type = get_unaligned_be32(sendbuf + 14);
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switch (type) {
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case 4:
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index = get_unaligned_be32(sendbuf + 18);
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printf("Get flags index %#02x\n", index);
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*recv_len = 22;
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memset(recvbuf, '\0', *recv_len);
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put_unaligned_be32(22, recvbuf +
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TPM_RESPONSE_HEADER_LENGTH);
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data = recvbuf + TPM_RESPONSE_HEADER_LENGTH +
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sizeof(uint32_t);
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switch (index) {
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case FIRMWARE_NV_INDEX:
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break;
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case KERNEL_NV_INDEX:
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/* TPM_NV_PER_PPWRITE */
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put_unaligned_be32(1, data +
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NV_DATA_PUBLIC_PERMISSIONS_OFFSET);
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break;
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}
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break;
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case 0x11: /* TPM_CAP_NV_INDEX */
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index = get_unaligned_be32(sendbuf + 18);
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printf("Get cap nv index %#02x\n", index);
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put_unaligned_be32(22, recvbuf +
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TPM_RESPONSE_HEADER_LENGTH);
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break;
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default:
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printf(" ** Unknown 0x65 command type %#02x\n",
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type);
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return -1;
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}
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break;
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case 0xcd: /* nvwrite */
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index = get_unaligned_be32(sendbuf + 10);
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length = get_unaligned_be32(sendbuf + 18);
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seq = index_to_seq(index);
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if (seq < 0)
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return -1;
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printf("tpm: nvwrite index=%#02x, len=%#02x\n", index, length);
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memcpy(&tpm->nvdata[seq], sendbuf + 22, length);
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*recv_len = 12;
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memset(recvbuf, '\0', *recv_len);
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break;
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case 0xcf: /* nvread */
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index = get_unaligned_be32(sendbuf + 10);
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length = get_unaligned_be32(sendbuf + 18);
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seq = index_to_seq(index);
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if (seq < 0)
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return -1;
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printf("tpm: nvread index=%#02x, len=%#02x\n", index, length);
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*recv_len = TPM_RESPONSE_HEADER_LENGTH + sizeof(uint32_t) +
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length;
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memset(recvbuf, '\0', *recv_len);
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put_unaligned_be32(length, recvbuf +
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TPM_RESPONSE_HEADER_LENGTH);
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if (seq == NV_SEQ_KERNEL) {
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struct rollback_space_kernel rsk;
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data = recvbuf + TPM_RESPONSE_HEADER_LENGTH +
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sizeof(uint32_t);
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memset(&rsk, 0, sizeof(struct rollback_space_kernel));
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rsk.struct_version = 2;
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rsk.uid = ROLLBACK_SPACE_KERNEL_UID;
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rsk.crc8 = crc8(0, (unsigned char *)&rsk,
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offsetof(struct rollback_space_kernel,
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crc8));
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memcpy(data, &rsk, sizeof(rsk));
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} else {
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memcpy(recvbuf + TPM_RESPONSE_HEADER_LENGTH +
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sizeof(uint32_t), &tpm->nvdata[seq], length);
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}
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break;
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case 0x14: /* tpm extend */
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case 0x15: /* pcr read */
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case 0x5d: /* force clear */
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case 0x6f: /* physical enable */
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case 0x72: /* physical set deactivated */
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case 0x99: /* startup */
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case 0x4000000a: /* assert physical presence */
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*recv_len = 12;
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memset(recvbuf, '\0', *recv_len);
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break;
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default:
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printf("Unknown tpm command %02x\n", code);
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return -1;
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}
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return 0;
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}
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static int sandbox_tpm_get_desc(struct udevice *dev, char *buf, int size)
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{
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if (size < 15)
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return -ENOSPC;
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return snprintf(buf, size, "sandbox TPM");
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}
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static int sandbox_tpm_probe(struct udevice *dev)
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{
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struct tpm_state *tpm = dev_get_priv(dev);
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memcpy(tpm, &g_state, sizeof(*tpm));
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return 0;
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}
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static int sandbox_tpm_open(struct udevice *dev)
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{
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return 0;
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}
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static int sandbox_tpm_close(struct udevice *dev)
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{
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return 0;
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}
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static const struct tpm_ops sandbox_tpm_ops = {
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.open = sandbox_tpm_open,
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.close = sandbox_tpm_close,
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.get_desc = sandbox_tpm_get_desc,
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.xfer = sandbox_tpm_xfer,
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};
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static const struct udevice_id sandbox_tpm_ids[] = {
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{ .compatible = "google,sandbox-tpm" },
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{ }
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};
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U_BOOT_DRIVER(sandbox_tpm) = {
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.name = "sandbox_tpm",
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.id = UCLASS_TPM,
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.of_match = sandbox_tpm_ids,
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.ops = &sandbox_tpm_ops,
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.probe = sandbox_tpm_probe,
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.priv_auto_alloc_size = sizeof(struct tpm_state),
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};
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