summaryrefslogtreecommitdiff
path: root/drivers/tpm/tpm_tis_sandbox.c
blob: ed4b0391278307c77ffefcd6f7464b30527149d6 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
/*
 * Copyright (c) 2013 Google, Inc
 *
 * SPDX-License-Identifier:	GPL-2.0+
 */

#include <common.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];
} 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(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, 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;
}

int tis_sendrecv(const u8 *sendbuf, size_t send_size,
		 u8 *recvbuf, size_t *recv_len)
{
	struct tpm_state *tpm = &state;
	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;
}

int tis_open(void)
{
	printf("%s\n", __func__);
	return 0;
}

int tis_close(void)
{
	printf("%s\n", __func__);
	return 0;
}

int tis_init(void)
{
	printf("%s\n", __func__);
	return 0;
}