xref: /openbmc/u-boot/board/gdsys/a38x/hre.c (revision ecab65e4) 
1 // SPDX-License-Identifier: GPL-2.0+
2 /*
3  * (C) Copyright 2013
4  * Reinhard Pfau, Guntermann & Drunck GmbH, reinhard.pfau@gdsys.cc
5  */
6 
7 #include <common.h>
8 #include <malloc.h>
9 #include <fs.h>
10 #include <i2c.h>
11 #include <mmc.h>
12 #include <tpm-v1.h>
13 #include <u-boot/sha1.h>
14 #include <asm/byteorder.h>
15 #include <asm/unaligned.h>
16 #include <pca9698.h>
17 
18 #include "hre.h"
19 
20 /* other constants */
21 enum {
22 	ESDHC_BOOT_IMAGE_SIG_OFS	= 0x40,
23 	ESDHC_BOOT_IMAGE_SIZE_OFS	= 0x48,
24 	ESDHC_BOOT_IMAGE_ADDR_OFS	= 0x50,
25 	ESDHC_BOOT_IMAGE_TARGET_OFS	= 0x58,
26 	ESDHC_BOOT_IMAGE_ENTRY_OFS	= 0x60,
27 };
28 
29 enum {
30 	I2C_SOC_0 = 0,
31 	I2C_SOC_1 = 1,
32 };
33 
34 enum access_mode {
35 	HREG_NONE	= 0,
36 	HREG_RD		= 1,
37 	HREG_WR		= 2,
38 	HREG_RDWR	= 3,
39 };
40 
41 /* register constants */
42 enum {
43 	FIX_HREG_DEVICE_ID_HASH	= 0,
44 	FIX_HREG_UNUSED1	= 1,
45 	FIX_HREG_UNUSED2	= 2,
46 	FIX_HREG_VENDOR		= 3,
47 	COUNT_FIX_HREGS
48 };
49 
50 static struct h_reg pcr_hregs[24];
51 static struct h_reg fix_hregs[COUNT_FIX_HREGS];
52 static struct h_reg var_hregs[8];
53 
54 /* hre opcodes */
55 enum {
56 	/* opcodes w/o data */
57 	HRE_NOP		= 0x00,
58 	HRE_SYNC	= HRE_NOP,
59 	HRE_CHECK0	= 0x01,
60 	/* opcodes w/o data, w/ sync dst */
61 	/* opcodes w/ data */
62 	HRE_LOAD	= 0x81,
63 	/* opcodes w/data, w/sync dst */
64 	HRE_XOR		= 0xC1,
65 	HRE_AND		= 0xC2,
66 	HRE_OR		= 0xC3,
67 	HRE_EXTEND	= 0xC4,
68 	HRE_LOADKEY	= 0xC5,
69 };
70 
71 /* hre errors */
72 enum {
73 	HRE_E_OK	= 0,
74 	HRE_E_TPM_FAILURE,
75 	HRE_E_INVALID_HREG,
76 };
77 
78 static uint64_t device_id;
79 static uint64_t device_cl;
80 static uint64_t device_type;
81 
82 static uint32_t platform_key_handle;
83 
84 static uint32_t hre_tpm_err;
85 static int hre_err = HRE_E_OK;
86 
87 #define IS_PCR_HREG(spec) ((spec) & 0x20)
88 #define IS_FIX_HREG(spec) (((spec) & 0x38) == 0x08)
89 #define IS_VAR_HREG(spec) (((spec) & 0x38) == 0x10)
90 #define HREG_IDX(spec) ((spec) & (IS_PCR_HREG(spec) ? 0x1f : 0x7))
91 
92 static const uint8_t vendor[] = "Guntermann & Drunck";
93 
94 /**
95  * @brief get the size of a given (TPM) NV area
96  * @param tpm		TPM device
97  * @param index	NV index of the area to get size for
98  * @param size	pointer to the size
99  * @return 0 on success, != 0 on error
100  */
101 static int get_tpm_nv_size(struct udevice *tpm, uint32_t index, uint32_t *size)
102 {
103 	uint32_t err;
104 	uint8_t info[72];
105 	uint8_t *ptr;
106 	uint16_t v16;
107 
108 	err = tpm_get_capability(tpm, TPM_CAP_NV_INDEX, index,
109 				 info, sizeof(info));
110 	if (err) {
111 		printf("tpm_get_capability(CAP_NV_INDEX, %08x) failed: %u\n",
112 		       index, err);
113 		return 1;
114 	}
115 
116 	/* skip tag and nvIndex */
117 	ptr = info + 6;
118 	/* skip 2 pcr info fields */
119 	v16 = get_unaligned_be16(ptr);
120 	ptr += 2 + v16 + 1 + 20;
121 	v16 = get_unaligned_be16(ptr);
122 	ptr += 2 + v16 + 1 + 20;
123 	/* skip permission and flags */
124 	ptr += 6 + 3;
125 
126 	*size = get_unaligned_be32(ptr);
127 	return 0;
128 }
129 
130 /**
131  * @brief search for a key by usage auth and pub key hash.
132  * @param tpm		TPM device
133  * @param auth	usage auth of the key to search for
134  * @param pubkey_digest	(SHA1) hash of the pub key structure of the key
135  * @param[out] handle	the handle of the key iff found
136  * @return 0 if key was found in TPM; != 0 if not.
137  */
138 static int find_key(struct udevice *tpm, const uint8_t auth[20],
139 		    const uint8_t pubkey_digest[20], uint32_t *handle)
140 {
141 	uint16_t key_count;
142 	uint32_t key_handles[10];
143 	uint8_t buf[288];
144 	uint8_t *ptr;
145 	uint32_t err;
146 	uint8_t digest[20];
147 	size_t buf_len;
148 	unsigned int i;
149 
150 	/* fetch list of already loaded keys in the TPM */
151 	err = tpm_get_capability(tpm, TPM_CAP_HANDLE, TPM_RT_KEY, buf,
152 				 sizeof(buf));
153 	if (err)
154 		return -1;
155 	key_count = get_unaligned_be16(buf);
156 	ptr = buf + 2;
157 	for (i = 0; i < key_count; ++i, ptr += 4)
158 		key_handles[i] = get_unaligned_be32(ptr);
159 
160 	/* now search a(/ the) key which we can access with the given auth */
161 	for (i = 0; i < key_count; ++i) {
162 		buf_len = sizeof(buf);
163 		err = tpm_get_pub_key_oiap(tpm, key_handles[i], auth, buf,
164 					   &buf_len);
165 		if (err && err != TPM_AUTHFAIL)
166 			return -1;
167 		if (err)
168 			continue;
169 		sha1_csum(buf, buf_len, digest);
170 		if (!memcmp(digest, pubkey_digest, 20)) {
171 			*handle = key_handles[i];
172 			return 0;
173 		}
174 	}
175 	return 1;
176 }
177 
178 /**
179  * @brief read CCDM common data from TPM NV
180  * @param tpm		TPM device
181  * @return 0 if CCDM common data was found and read, !=0 if something failed.
182  */
183 static int read_common_data(struct udevice *tpm)
184 {
185 	uint32_t size = 0;
186 	uint32_t err;
187 	uint8_t buf[256];
188 	sha1_context ctx;
189 
190 	if (get_tpm_nv_size(tpm, NV_COMMON_DATA_INDEX, &size) ||
191 	    size < NV_COMMON_DATA_MIN_SIZE)
192 		return 1;
193 	err = tpm_nv_read_value(tpm, NV_COMMON_DATA_INDEX,
194 				buf, min(sizeof(buf), size));
195 	if (err) {
196 		printf("tpm_nv_read_value() failed: %u\n", err);
197 		return 1;
198 	}
199 
200 	device_id = get_unaligned_be64(buf);
201 	device_cl = get_unaligned_be64(buf + 8);
202 	device_type = get_unaligned_be64(buf + 16);
203 
204 	sha1_starts(&ctx);
205 	sha1_update(&ctx, buf, 24);
206 	sha1_finish(&ctx, fix_hregs[FIX_HREG_DEVICE_ID_HASH].digest);
207 	fix_hregs[FIX_HREG_DEVICE_ID_HASH].valid = true;
208 
209 	platform_key_handle = get_unaligned_be32(buf + 24);
210 
211 	return 0;
212 }
213 
214 /**
215  * @brief get pointer to  hash register by specification
216  * @param spec	specification of a hash register
217  * @return pointer to hash register or NULL if @a spec does not qualify a
218  * valid hash register; NULL else.
219  */
220 static struct h_reg *get_hreg(uint8_t spec)
221 {
222 	uint8_t idx;
223 
224 	idx = HREG_IDX(spec);
225 	if (IS_FIX_HREG(spec)) {
226 		if (idx < ARRAY_SIZE(fix_hregs))
227 			return fix_hregs + idx;
228 		hre_err = HRE_E_INVALID_HREG;
229 	} else if (IS_PCR_HREG(spec)) {
230 		if (idx < ARRAY_SIZE(pcr_hregs))
231 			return pcr_hregs + idx;
232 		hre_err = HRE_E_INVALID_HREG;
233 	} else if (IS_VAR_HREG(spec)) {
234 		if (idx < ARRAY_SIZE(var_hregs))
235 			return var_hregs + idx;
236 		hre_err = HRE_E_INVALID_HREG;
237 	}
238 	return NULL;
239 }
240 
241 /**
242  * @brief get pointer of a hash register by specification and usage.
243  * @param tpm		TPM device
244  * @param spec	specification of a hash register
245  * @param mode	access mode (read or write or read/write)
246  * @return pointer to hash register if found and valid; NULL else.
247  *
248  * This func uses @a get_reg() to determine the hash register for a given spec.
249  * If a register is found it is validated according to the desired access mode.
250  * The value of automatic registers (PCR register and fixed registers) is
251  * loaded or computed on read access.
252  */
253 static struct h_reg *access_hreg(struct udevice *tpm, uint8_t spec,
254 				 enum access_mode mode)
255 {
256 	struct h_reg *result;
257 
258 	result = get_hreg(spec);
259 	if (!result)
260 		return NULL;
261 
262 	if (mode & HREG_WR) {
263 		if (IS_FIX_HREG(spec)) {
264 			hre_err = HRE_E_INVALID_HREG;
265 			return NULL;
266 		}
267 	}
268 	if (mode & HREG_RD) {
269 		if (!result->valid) {
270 			if (IS_PCR_HREG(spec)) {
271 				hre_tpm_err = tpm_pcr_read(tpm, HREG_IDX(spec),
272 					result->digest, 20);
273 				result->valid = (hre_tpm_err == TPM_SUCCESS);
274 			} else if (IS_FIX_HREG(spec)) {
275 				switch (HREG_IDX(spec)) {
276 				case FIX_HREG_DEVICE_ID_HASH:
277 					read_common_data(tpm);
278 					break;
279 				case FIX_HREG_VENDOR:
280 					memcpy(result->digest, vendor, 20);
281 					result->valid = true;
282 					break;
283 				}
284 			} else {
285 				result->valid = true;
286 			}
287 		}
288 		if (!result->valid) {
289 			hre_err = HRE_E_INVALID_HREG;
290 			return NULL;
291 		}
292 	}
293 
294 	return result;
295 }
296 
297 static void *compute_and(void *_dst, const void *_src, size_t n)
298 {
299 	uint8_t *dst = _dst;
300 	const uint8_t *src = _src;
301 	size_t i;
302 
303 	for (i = n; i-- > 0; )
304 		*dst++ &= *src++;
305 
306 	return _dst;
307 }
308 
309 static void *compute_or(void *_dst, const void *_src, size_t n)
310 {
311 	uint8_t *dst = _dst;
312 	const uint8_t *src = _src;
313 	size_t i;
314 
315 	for (i = n; i-- > 0; )
316 		*dst++ |= *src++;
317 
318 	return _dst;
319 }
320 
321 static void *compute_xor(void *_dst, const void *_src, size_t n)
322 {
323 	uint8_t *dst = _dst;
324 	const uint8_t *src = _src;
325 	size_t i;
326 
327 	for (i = n; i-- > 0; )
328 		*dst++ ^= *src++;
329 
330 	return _dst;
331 }
332 
333 static void *compute_extend(void *_dst, const void *_src, size_t n)
334 {
335 	uint8_t digest[20];
336 	sha1_context ctx;
337 
338 	sha1_starts(&ctx);
339 	sha1_update(&ctx, _dst, n);
340 	sha1_update(&ctx, _src, n);
341 	sha1_finish(&ctx, digest);
342 	memcpy(_dst, digest, min(n, sizeof(digest)));
343 
344 	return _dst;
345 }
346 
347 static int hre_op_loadkey(struct udevice *tpm, struct h_reg *src_reg,
348 			  struct h_reg *dst_reg, const void *key,
349 			  size_t key_size)
350 {
351 	uint32_t parent_handle;
352 	uint32_t key_handle;
353 
354 	if (!src_reg || !dst_reg || !src_reg->valid || !dst_reg->valid)
355 		return -1;
356 	if (find_key(tpm, src_reg->digest, dst_reg->digest, &parent_handle))
357 		return -1;
358 	hre_tpm_err = tpm_load_key2_oiap(tpm, parent_handle, key, key_size,
359 					 src_reg->digest, &key_handle);
360 	if (hre_tpm_err) {
361 		hre_err = HRE_E_TPM_FAILURE;
362 		return -1;
363 	}
364 
365 	return 0;
366 }
367 
368 /**
369  * @brief executes the next opcode on the hash register engine.
370  * @param tpm		TPM device
371  * @param[in,out] ip	pointer to the opcode (instruction pointer)
372  * @param[in,out] code_size	(remaining) size of the code
373  * @return new instruction pointer on success, NULL on error.
374  */
375 static const uint8_t *hre_execute_op(struct udevice *tpm, const uint8_t **ip,
376 				     size_t *code_size)
377 {
378 	bool dst_modified = false;
379 	uint32_t ins;
380 	uint8_t opcode;
381 	uint8_t src_spec;
382 	uint8_t dst_spec;
383 	uint16_t data_size;
384 	struct h_reg *src_reg, *dst_reg;
385 	uint8_t buf[20];
386 	const uint8_t *src_buf, *data;
387 	uint8_t *ptr;
388 	int i;
389 	void * (*bin_func)(void *, const void *, size_t);
390 
391 	if (*code_size < 4)
392 		return NULL;
393 
394 	ins = get_unaligned_be32(*ip);
395 	opcode = **ip;
396 	data = *ip + 4;
397 	src_spec = (ins >> 18) & 0x3f;
398 	dst_spec = (ins >> 12) & 0x3f;
399 	data_size = (ins & 0x7ff);
400 
401 	debug("HRE: ins=%08x (op=%02x, s=%02x, d=%02x, L=%d)\n", ins,
402 	      opcode, src_spec, dst_spec, data_size);
403 
404 	if ((opcode & 0x80) && (data_size + 4) > *code_size)
405 		return NULL;
406 
407 	src_reg = access_hreg(tpm, src_spec, HREG_RD);
408 	if (hre_err || hre_tpm_err)
409 		return NULL;
410 	dst_reg = access_hreg(tpm, dst_spec,
411 			      (opcode & 0x40) ? HREG_RDWR : HREG_WR);
412 	if (hre_err || hre_tpm_err)
413 		return NULL;
414 
415 	switch (opcode) {
416 	case HRE_NOP:
417 		goto end;
418 	case HRE_CHECK0:
419 		if (src_reg) {
420 			for (i = 0; i < 20; ++i) {
421 				if (src_reg->digest[i])
422 					return NULL;
423 			}
424 		}
425 		break;
426 	case HRE_LOAD:
427 		bin_func = memcpy;
428 		goto do_bin_func;
429 	case HRE_XOR:
430 		bin_func = compute_xor;
431 		goto do_bin_func;
432 	case HRE_AND:
433 		bin_func = compute_and;
434 		goto do_bin_func;
435 	case HRE_OR:
436 		bin_func = compute_or;
437 		goto do_bin_func;
438 	case HRE_EXTEND:
439 		bin_func = compute_extend;
440 do_bin_func:
441 		if (!dst_reg)
442 			return NULL;
443 		if (src_reg) {
444 			src_buf = src_reg->digest;
445 		} else {
446 			if (!data_size) {
447 				memset(buf, 0, 20);
448 				src_buf = buf;
449 			} else if (data_size == 1) {
450 				memset(buf, *data, 20);
451 				src_buf = buf;
452 			} else if (data_size >= 20) {
453 				src_buf = data;
454 			} else {
455 				src_buf = buf;
456 				for (ptr = (uint8_t *)src_buf, i = 20; i > 0;
457 					i -= data_size, ptr += data_size)
458 					memcpy(ptr, data,
459 					       min_t(size_t, i, data_size));
460 			}
461 		}
462 		bin_func(dst_reg->digest, src_buf, 20);
463 		dst_reg->valid = true;
464 		dst_modified = true;
465 		break;
466 	case HRE_LOADKEY:
467 		if (hre_op_loadkey(tpm, src_reg, dst_reg, data, data_size))
468 			return NULL;
469 		break;
470 	default:
471 		return NULL;
472 	}
473 
474 	if (dst_reg && dst_modified && IS_PCR_HREG(dst_spec)) {
475 		hre_tpm_err = tpm_extend(tpm, HREG_IDX(dst_spec),
476 					 dst_reg->digest, dst_reg->digest);
477 		if (hre_tpm_err) {
478 			hre_err = HRE_E_TPM_FAILURE;
479 			return NULL;
480 		}
481 	}
482 end:
483 	*ip += 4;
484 	*code_size -= 4;
485 	if (opcode & 0x80) {
486 		*ip += data_size;
487 		*code_size -= data_size;
488 	}
489 
490 	return *ip;
491 }
492 
493 /**
494  * @brief runs a program on the hash register engine.
495  * @param tpm		TPM device
496  * @param code		pointer to the (HRE) code.
497  * @param code_size	size of the code (in bytes).
498  * @return 0 on success, != 0 on failure.
499  */
500 int hre_run_program(struct udevice *tpm, const uint8_t *code, size_t code_size)
501 {
502 	size_t code_left;
503 	const uint8_t *ip = code;
504 
505 	code_left = code_size;
506 	hre_tpm_err = 0;
507 	hre_err = HRE_E_OK;
508 	while (code_left > 0)
509 		if (!hre_execute_op(tpm, &ip, &code_left))
510 			return -1;
511 
512 	return hre_err;
513 }
514 
515 int hre_verify_program(struct key_program *prg)
516 {
517 	uint32_t crc;
518 
519 	crc = crc32(0, prg->code, prg->code_size);
520 
521 	if (crc != prg->code_crc) {
522 		printf("HRC crc mismatch: %08x != %08x\n",
523 		       crc, prg->code_crc);
524 		return 1;
525 	}
526 	return 0;
527 }
528