xref: /rk3399_rockchip-uboot/board/freescale/common/fsl_validate.c (revision d0a6d7ce55ec40d23ad96b549d596afd8f70735c)
1 /*
2  * Copyright 2015 Freescale Semiconductor, Inc.
3  *
4  * SPDX-License-Identifier:	GPL-2.0+
5  */
6 
7 #include <common.h>
8 #include <fsl_validate.h>
9 #include <fsl_secboot_err.h>
10 #include <fsl_sfp.h>
11 #include <fsl_sec.h>
12 #include <command.h>
13 #include <malloc.h>
14 #include <dm/uclass.h>
15 #include <u-boot/rsa-mod-exp.h>
16 #include <hash.h>
17 #include <fsl_secboot_err.h>
18 #ifdef CONFIG_LS102XA
19 #include <asm/arch/immap_ls102xa.h>
20 #endif
21 
22 #define SHA256_BITS	256
23 #define SHA256_BYTES	(256/8)
24 #define SHA256_NIBBLES	(256/4)
25 #define NUM_HEX_CHARS	(sizeof(ulong) * 2)
26 
27 #define CHECK_KEY_LEN(key_len)	(((key_len) == 2 * KEY_SIZE_BYTES / 4) || \
28 				 ((key_len) == 2 * KEY_SIZE_BYTES / 2) || \
29 				 ((key_len) == 2 * KEY_SIZE_BYTES))
30 
31 /* This array contains DER value for SHA-256 */
32 static const u8 hash_identifier[] = { 0x30, 0x31, 0x30, 0x0d, 0x06, 0x09, 0x60,
33 		0x86, 0x48, 0x01, 0x65,	0x03, 0x04, 0x02, 0x01, 0x05, 0x00,
34 		0x04, 0x20
35 		};
36 
37 static u8 hash_val[SHA256_BYTES];
38 static const u8 barker_code[ESBC_BARKER_LEN] = { 0x68, 0x39, 0x27, 0x81 };
39 
40 void branch_to_self(void) __attribute__ ((noreturn));
41 
42 /*
43  * This function will put core in infinite loop.
44  * This will be called when the ESBC can not proceed further due
45  * to some unknown errors.
46  */
47 void branch_to_self(void)
48 {
49 	printf("Core is in infinite loop due to errors.\n");
50 self:
51 	goto self;
52 }
53 
54 #if defined(CONFIG_FSL_ISBC_KEY_EXT)
55 static u32 check_ie(struct fsl_secboot_img_priv *img)
56 {
57 	if (img->hdr.ie_flag)
58 		return 1;
59 
60 	return 0;
61 }
62 
63 /* This function returns the CSF Header Address of uboot
64  * For MPC85xx based platforms, the LAW mapping for NOR
65  * flash changes in uboot code. Hence the offset needs
66  * to be calculated and added to the new NOR flash base
67  * address
68  */
69 #if defined(CONFIG_MPC85xx)
70 int get_csf_base_addr(u32 *csf_addr, u32 *flash_base_addr)
71 {
72 	struct ccsr_gur __iomem *gur = (void *)(CONFIG_SYS_MPC85xx_GUTS_ADDR);
73 	u32 csf_hdr_addr = in_be32(&gur->scratchrw[0]);
74 	u32 csf_flash_offset = csf_hdr_addr & ~(CONFIG_SYS_PBI_FLASH_BASE);
75 	u32 flash_addr, addr;
76 	int found = 0;
77 	int i = 0;
78 
79 	for (i = 0; i < CONFIG_SYS_MAX_FLASH_BANKS; i++) {
80 		flash_addr = flash_info[i].start[0];
81 		addr = flash_info[i].start[0] + csf_flash_offset;
82 		if (memcmp((u8 *)addr, barker_code, ESBC_BARKER_LEN) == 0) {
83 			debug("Barker found on addr %x\n", addr);
84 			found = 1;
85 			break;
86 		}
87 	}
88 
89 	if (!found)
90 		return -1;
91 
92 	*csf_addr = addr;
93 	*flash_base_addr = flash_addr;
94 
95 	return 0;
96 }
97 #else
98 /* For platforms like LS1020, correct flash address is present in
99  * the header. So the function reqturns flash base address as 0
100  */
101 int get_csf_base_addr(u32 *csf_addr, u32 *flash_base_addr)
102 {
103 	struct ccsr_gur __iomem *gur = (void *)(CONFIG_SYS_FSL_GUTS_ADDR);
104 	u32 csf_hdr_addr = in_be32(&gur->scratchrw[0]);
105 
106 	if (memcmp((u8 *)(uintptr_t)csf_hdr_addr,
107 		   barker_code, ESBC_BARKER_LEN))
108 		return -1;
109 
110 	*csf_addr = csf_hdr_addr;
111 	*flash_base_addr = 0;
112 	return 0;
113 }
114 #endif
115 
116 static int get_ie_info_addr(u32 *ie_addr)
117 {
118 	struct fsl_secboot_img_hdr *hdr;
119 	struct fsl_secboot_sg_table *sg_tbl;
120 	u32 flash_base_addr, csf_addr;
121 
122 	if (get_csf_base_addr(&csf_addr, &flash_base_addr))
123 		return -1;
124 
125 	hdr = (struct fsl_secboot_img_hdr *)(uintptr_t)csf_addr;
126 
127 	/* For SoC's with Trust Architecture v1 with corenet bus
128 	 * the sg table field in CSF header has absolute address
129 	 * for sg table in memory. In other Trust Architecture,
130 	 * this field specifies the offset of sg table from the
131 	 * base address of CSF Header
132 	 */
133 #if defined(CONFIG_FSL_TRUST_ARCH_v1) && defined(CONFIG_FSL_CORENET)
134 	sg_tbl = (struct fsl_secboot_sg_table *)
135 		 (((u32)hdr->psgtable & ~(CONFIG_SYS_PBI_FLASH_BASE)) +
136 		  flash_base_addr);
137 #else
138 	sg_tbl = (struct fsl_secboot_sg_table *)(uintptr_t)(csf_addr +
139 						 (u32)hdr->psgtable);
140 #endif
141 
142 	/* IE Key Table is the first entry in the SG Table */
143 #if defined(CONFIG_MPC85xx)
144 	*ie_addr = (sg_tbl->src_addr & ~(CONFIG_SYS_PBI_FLASH_BASE)) +
145 		   flash_base_addr;
146 #else
147 	*ie_addr = sg_tbl->src_addr;
148 #endif
149 
150 	debug("IE Table address is %x\n", *ie_addr);
151 	return 0;
152 }
153 
154 #endif
155 
156 #ifdef CONFIG_KEY_REVOCATION
157 /* This function checks srk_table_flag in header and set/reset srk_flag.*/
158 static u32 check_srk(struct fsl_secboot_img_priv *img)
159 {
160 	if (img->hdr.len_kr.srk_table_flag & SRK_FLAG)
161 		return 1;
162 
163 	return 0;
164 }
165 
166 /* This function returns ospr's key_revoc values.*/
167 static u32 get_key_revoc(void)
168 {
169 	struct ccsr_sfp_regs *sfp_regs = (void *)(CONFIG_SYS_SFP_ADDR);
170 	return (sfp_in32(&sfp_regs->ospr) & OSPR_KEY_REVOC_MASK) >>
171 		OSPR_KEY_REVOC_SHIFT;
172 }
173 
174 /* This function checks if selected key is revoked or not.*/
175 static u32 is_key_revoked(u32 keynum, u32 rev_flag)
176 {
177 	if (keynum == UNREVOCABLE_KEY)
178 		return 0;
179 
180 	if ((u32)(1 << (ALIGN_REVOC_KEY - keynum)) & rev_flag)
181 		return 1;
182 
183 	return 0;
184 }
185 
186 /* It read validates srk_table key lengths.*/
187 static u32 read_validate_srk_tbl(struct fsl_secboot_img_priv *img)
188 {
189 	int i = 0;
190 	u32 ret, key_num, key_revoc_flag, size;
191 	struct fsl_secboot_img_hdr *hdr = &img->hdr;
192 	void *esbc = (u8 *)(uintptr_t)img->ehdrloc;
193 
194 	if ((hdr->len_kr.num_srk == 0) ||
195 	    (hdr->len_kr.num_srk > MAX_KEY_ENTRIES))
196 		return ERROR_ESBC_CLIENT_HEADER_INVALID_SRK_NUM_ENTRY;
197 
198 	key_num = hdr->len_kr.srk_sel;
199 	if (key_num == 0 || key_num > hdr->len_kr.num_srk)
200 		return ERROR_ESBC_CLIENT_HEADER_INVALID_KEY_NUM;
201 
202 	/* Get revoc key from sfp */
203 	key_revoc_flag = get_key_revoc();
204 	ret = is_key_revoked(key_num, key_revoc_flag);
205 	if (ret)
206 		return ERROR_ESBC_CLIENT_HEADER_KEY_REVOKED;
207 
208 	size = hdr->len_kr.num_srk * sizeof(struct srk_table);
209 
210 	memcpy(&img->srk_tbl, esbc + hdr->srk_tbl_off, size);
211 
212 	for (i = 0; i < hdr->len_kr.num_srk; i++) {
213 		if (!CHECK_KEY_LEN(img->srk_tbl[i].key_len))
214 			return ERROR_ESBC_CLIENT_HEADER_INV_SRK_ENTRY_KEYLEN;
215 	}
216 
217 	img->key_len = img->srk_tbl[key_num - 1].key_len;
218 
219 	memcpy(&img->img_key, &(img->srk_tbl[key_num - 1].pkey),
220 	       img->key_len);
221 
222 	return 0;
223 }
224 #endif
225 
226 static u32 read_validate_single_key(struct fsl_secboot_img_priv *img)
227 {
228 	struct fsl_secboot_img_hdr *hdr = &img->hdr;
229 	void *esbc = (u8 *)(uintptr_t)img->ehdrloc;
230 
231 	/* check key length */
232 	if (!CHECK_KEY_LEN(hdr->key_len))
233 		return ERROR_ESBC_CLIENT_HEADER_KEY_LEN;
234 
235 	memcpy(&img->img_key, esbc + hdr->pkey, hdr->key_len);
236 
237 	img->key_len = hdr->key_len;
238 
239 	return 0;
240 }
241 
242 #if defined(CONFIG_FSL_ISBC_KEY_EXT)
243 static u32 read_validate_ie_tbl(struct fsl_secboot_img_priv *img)
244 {
245 	struct fsl_secboot_img_hdr *hdr = &img->hdr;
246 	u32 ie_key_len, ie_revoc_flag, ie_num;
247 	struct ie_key_info *ie_info;
248 
249 	if (get_ie_info_addr(&img->ie_addr))
250 		return ERROR_IE_TABLE_NOT_FOUND;
251 	ie_info = (struct ie_key_info *)(uintptr_t)img->ie_addr;
252 	if (ie_info->num_keys == 0 || ie_info->num_keys > 32)
253 		return ERROR_ESBC_CLIENT_HEADER_INVALID_IE_NUM_ENTRY;
254 
255 	ie_num = hdr->ie_key_sel;
256 	if (ie_num == 0 || ie_num > ie_info->num_keys)
257 		return ERROR_ESBC_CLIENT_HEADER_INVALID_IE_KEY_NUM;
258 
259 	ie_revoc_flag = ie_info->key_revok;
260 	if ((u32)(1 << (ie_num - 1)) & ie_revoc_flag)
261 		return ERROR_ESBC_CLIENT_HEADER_IE_KEY_REVOKED;
262 
263 	ie_key_len = ie_info->ie_key_tbl[ie_num - 1].key_len;
264 
265 	if (!CHECK_KEY_LEN(ie_key_len))
266 		return ERROR_ESBC_CLIENT_HEADER_INV_IE_ENTRY_KEYLEN;
267 
268 	memcpy(&img->img_key, &(ie_info->ie_key_tbl[ie_num - 1].pkey),
269 	       ie_key_len);
270 
271 	img->key_len = ie_key_len;
272 	return 0;
273 }
274 #endif
275 
276 
277 /* This function return length of public key.*/
278 static inline u32 get_key_len(struct fsl_secboot_img_priv *img)
279 {
280 	return img->key_len;
281 }
282 
283 /*
284  * Handles the ESBC uboot client header verification failure.
285  * This  function  handles all the errors which might occur in the
286  * parsing and checking of ESBC uboot client header. It will also
287  * set the error bits in the SEC_MON.
288  */
289 static void fsl_secboot_header_verification_failure(void)
290 {
291 	struct ccsr_sec_mon_regs *sec_mon_regs = (void *)
292 						(CONFIG_SYS_SEC_MON_ADDR);
293 	struct ccsr_sfp_regs *sfp_regs = (void *)(CONFIG_SYS_SFP_ADDR);
294 	u32 sts = sec_mon_in32(&sec_mon_regs->hp_stat);
295 
296 	/* 29th bit of OSPR is ITS */
297 	u32 its = sfp_in32(&sfp_regs->ospr) >> 2;
298 
299 	/*
300 	 * Read the SEC_MON status register
301 	 * Read SSM_ST field
302 	 */
303 	sts = sec_mon_in32(&sec_mon_regs->hp_stat);
304 	if ((sts & HPSR_SSM_ST_MASK) == HPSR_SSM_ST_TRUST) {
305 		if (its == 1)
306 			change_sec_mon_state(HPSR_SSM_ST_TRUST,
307 					     HPSR_SSM_ST_SOFT_FAIL);
308 		else
309 			change_sec_mon_state(HPSR_SSM_ST_TRUST,
310 					     HPSR_SSM_ST_NON_SECURE);
311 	}
312 
313 	printf("Generating reset request\n");
314 	do_reset(NULL, 0, 0, NULL);
315 }
316 
317 /*
318  * Handles the ESBC uboot client image verification failure.
319  * This  function  handles all the errors which might occur in the
320  * public key hash comparison and signature verification of
321  * ESBC uboot client image. It will also
322  * set the error bits in the SEC_MON.
323  */
324 static void fsl_secboot_image_verification_failure(void)
325 {
326 	struct ccsr_sec_mon_regs *sec_mon_regs = (void *)
327 						(CONFIG_SYS_SEC_MON_ADDR);
328 	struct ccsr_sfp_regs *sfp_regs = (void *)(CONFIG_SYS_SFP_ADDR);
329 	u32 sts = sec_mon_in32(&sec_mon_regs->hp_stat);
330 
331 	u32 its = (sfp_in32(&sfp_regs->ospr) & ITS_MASK) >> ITS_BIT;
332 
333 	/*
334 	 * Read the SEC_MON status register
335 	 * Read SSM_ST field
336 	 */
337 	sts = sec_mon_in32(&sec_mon_regs->hp_stat);
338 	if ((sts & HPSR_SSM_ST_MASK) == HPSR_SSM_ST_TRUST) {
339 		if (its == 1) {
340 			change_sec_mon_state(HPSR_SSM_ST_TRUST,
341 					     HPSR_SSM_ST_SOFT_FAIL);
342 
343 			printf("Generating reset request\n");
344 			do_reset(NULL, 0, 0, NULL);
345 		} else {
346 			change_sec_mon_state(HPSR_SSM_ST_TRUST,
347 					     HPSR_SSM_ST_NON_SECURE);
348 		}
349 	}
350 }
351 
352 static void fsl_secboot_bootscript_parse_failure(void)
353 {
354 	fsl_secboot_header_verification_failure();
355 }
356 
357 /*
358  * Handles the errors in esbc boot.
359  * This  function  handles all the errors which might occur in the
360  * esbc boot phase. It will call the appropriate api to log the
361  * errors and set the error bits in the SEC_MON.
362  */
363 void fsl_secboot_handle_error(int error)
364 {
365 	const struct fsl_secboot_errcode *e;
366 
367 	for (e = fsl_secboot_errcodes; e->errcode != ERROR_ESBC_CLIENT_MAX;
368 		e++) {
369 		if (e->errcode == error)
370 			printf("ERROR :: %x :: %s\n", error, e->name);
371 	}
372 
373 	switch (error) {
374 	case ERROR_ESBC_CLIENT_HEADER_BARKER:
375 	case ERROR_ESBC_CLIENT_HEADER_IMG_SIZE:
376 	case ERROR_ESBC_CLIENT_HEADER_KEY_LEN:
377 	case ERROR_ESBC_CLIENT_HEADER_SIG_LEN:
378 	case ERROR_ESBC_CLIENT_HEADER_KEY_LEN_NOT_TWICE_SIG_LEN:
379 	case ERROR_ESBC_CLIENT_HEADER_KEY_MOD_1:
380 	case ERROR_ESBC_CLIENT_HEADER_KEY_MOD_2:
381 	case ERROR_ESBC_CLIENT_HEADER_SIG_KEY_MOD:
382 	case ERROR_ESBC_CLIENT_HEADER_SG_ESBC_EP:
383 	case ERROR_ESBC_CLIENT_HEADER_SG_ENTIRES_BAD:
384 #ifdef CONFIG_KEY_REVOCATION
385 	case ERROR_ESBC_CLIENT_HEADER_KEY_REVOKED:
386 	case ERROR_ESBC_CLIENT_HEADER_INVALID_SRK_NUM_ENTRY:
387 	case ERROR_ESBC_CLIENT_HEADER_INVALID_KEY_NUM:
388 	case ERROR_ESBC_CLIENT_HEADER_INV_SRK_ENTRY_KEYLEN:
389 #endif
390 #if defined(CONFIG_FSL_ISBC_KEY_EXT)
391 	/*@fallthrough@*/
392 	case ERROR_ESBC_CLIENT_HEADER_IE_KEY_REVOKED:
393 	case ERROR_ESBC_CLIENT_HEADER_INVALID_IE_NUM_ENTRY:
394 	case ERROR_ESBC_CLIENT_HEADER_INVALID_IE_KEY_NUM:
395 	case ERROR_ESBC_CLIENT_HEADER_INV_IE_ENTRY_KEYLEN:
396 	case ERROR_IE_TABLE_NOT_FOUND:
397 #endif
398 		fsl_secboot_header_verification_failure();
399 		break;
400 	case ERROR_ESBC_SEC_RESET:
401 	case ERROR_ESBC_SEC_DEQ:
402 	case ERROR_ESBC_SEC_ENQ:
403 	case ERROR_ESBC_SEC_DEQ_TO:
404 	case ERROR_ESBC_SEC_JOBQ_STATUS:
405 	case ERROR_ESBC_CLIENT_HASH_COMPARE_KEY:
406 	case ERROR_ESBC_CLIENT_HASH_COMPARE_EM:
407 		fsl_secboot_image_verification_failure();
408 		break;
409 	case ERROR_ESBC_MISSING_BOOTM:
410 		fsl_secboot_bootscript_parse_failure();
411 		break;
412 	case ERROR_ESBC_WRONG_CMD:
413 	default:
414 		branch_to_self();
415 		break;
416 	}
417 }
418 
419 static void fsl_secblk_handle_error(int error)
420 {
421 	switch (error) {
422 	case ERROR_ESBC_SEC_ENQ:
423 		fsl_secboot_handle_error(ERROR_ESBC_SEC_ENQ);
424 		break;
425 	case ERROR_ESBC_SEC_DEQ:
426 		fsl_secboot_handle_error(ERROR_ESBC_SEC_DEQ);
427 		break;
428 	case ERROR_ESBC_SEC_DEQ_TO:
429 		fsl_secboot_handle_error(ERROR_ESBC_SEC_DEQ_TO);
430 		break;
431 	default:
432 		printf("Job Queue Output status %x\n", error);
433 		fsl_secboot_handle_error(ERROR_ESBC_SEC_JOBQ_STATUS);
434 		break;
435 	}
436 }
437 
438 /*
439  * Calculate hash of key obtained via offset present in ESBC uboot
440  * client hdr. This function calculates the hash of key which is obtained
441  * through offset present in ESBC uboot client header.
442  */
443 static int calc_img_key_hash(struct fsl_secboot_img_priv *img)
444 {
445 	struct hash_algo *algo;
446 	void *ctx;
447 	int i, srk = 0;
448 	int ret = 0;
449 	const char *algo_name = "sha256";
450 
451 	/* Calculate hash of the esbc key */
452 	ret = hash_progressive_lookup_algo(algo_name, &algo);
453 	if (ret)
454 		return ret;
455 
456 	ret = algo->hash_init(algo, &ctx);
457 	if (ret)
458 		return ret;
459 
460 	/* Update hash for ESBC key */
461 #ifdef CONFIG_KEY_REVOCATION
462 	if (check_srk(img)) {
463 		ret = algo->hash_update(algo, ctx,
464 		      (u8 *)(uintptr_t)(img->ehdrloc + img->hdr.srk_tbl_off),
465 		      img->hdr.len_kr.num_srk * sizeof(struct srk_table), 1);
466 		srk = 1;
467 	}
468 #endif
469 	if (!srk)
470 		ret = algo->hash_update(algo, ctx,
471 			img->img_key, img->key_len, 1);
472 	if (ret)
473 		return ret;
474 
475 	/* Copy hash at destination buffer */
476 	ret = algo->hash_finish(algo, ctx, hash_val, algo->digest_size);
477 	if (ret)
478 		return ret;
479 
480 	for (i = 0; i < SHA256_BYTES; i++)
481 		img->img_key_hash[i] = hash_val[i];
482 
483 	return 0;
484 }
485 
486 /*
487  * Calculate hash of ESBC hdr and ESBC. This function calculates the
488  * single hash of ESBC header and ESBC image. If SG flag is on, all
489  * SG entries are also hashed alongwith the complete SG table.
490  */
491 static int calc_esbchdr_esbc_hash(struct fsl_secboot_img_priv *img)
492 {
493 	struct hash_algo *algo;
494 	void *ctx;
495 	int ret = 0;
496 	int key_hash = 0;
497 	const char *algo_name = "sha256";
498 
499 	/* Calculate the hash of the ESBC */
500 	ret = hash_progressive_lookup_algo(algo_name, &algo);
501 	if (ret)
502 		return ret;
503 
504 	ret = algo->hash_init(algo, &ctx);
505 	/* Copy hash at destination buffer */
506 	if (ret)
507 		return ret;
508 
509 	/* Update hash for CSF Header */
510 	ret = algo->hash_update(algo, ctx,
511 		(u8 *)&img->hdr, sizeof(struct fsl_secboot_img_hdr), 0);
512 	if (ret)
513 		return ret;
514 
515 	/* Update the hash with that of srk table if srk flag is 1
516 	 * If IE Table is selected, key is not added in the hash
517 	 * If neither srk table nor IE key table available, add key
518 	 * from header in the hash calculation
519 	 */
520 #ifdef CONFIG_KEY_REVOCATION
521 	if (check_srk(img)) {
522 		ret = algo->hash_update(algo, ctx,
523 		      (u8 *)(uintptr_t)(img->ehdrloc + img->hdr.srk_tbl_off),
524 		      img->hdr.len_kr.num_srk * sizeof(struct srk_table), 0);
525 		key_hash = 1;
526 	}
527 #endif
528 #if defined(CONFIG_FSL_ISBC_KEY_EXT)
529 	if (!key_hash && check_ie(img))
530 		key_hash = 1;
531 #endif
532 	if (!key_hash)
533 		ret = algo->hash_update(algo, ctx,
534 			img->img_key, img->hdr.key_len, 0);
535 	if (ret)
536 		return ret;
537 
538 	/* Update hash for actual Image */
539 	ret = algo->hash_update(algo, ctx,
540 		(u8 *)img->img_addr, img->img_size, 1);
541 	if (ret)
542 		return ret;
543 
544 	/* Copy hash at destination buffer */
545 	ret = algo->hash_finish(algo, ctx, hash_val, algo->digest_size);
546 	if (ret)
547 		return ret;
548 
549 	return 0;
550 }
551 
552 /*
553  * Construct encoded hash EM' wrt PKCSv1.5. This function calculates the
554  * pointers for padding, DER value and hash. And finally, constructs EM'
555  * which includes hash of complete CSF header and ESBC image. If SG flag
556  * is on, hash of SG table and entries is also included.
557  */
558 static void construct_img_encoded_hash_second(struct fsl_secboot_img_priv *img)
559 {
560 	/*
561 	 * RSA PKCSv1.5 encoding format for encoded message is below
562 	 * EM = 0x0 || 0x1 || PS || 0x0 || DER || Hash
563 	 * PS is Padding String
564 	 * DER is DER value for SHA-256
565 	 * Hash is SHA-256 hash
566 	 * *********************************************************
567 	 * representative points to first byte of EM initially and is
568 	 * filled with 0x0
569 	 * representative is incremented by 1 and second byte is filled
570 	 * with 0x1
571 	 * padding points to third byte of EM
572 	 * digest points to full length of EM - 32 bytes
573 	 * hash_id (DER value) points to 19 bytes before pDigest
574 	 * separator is one byte which separates padding and DER
575 	 */
576 
577 	size_t len;
578 	u8 *representative;
579 	u8 *padding, *digest;
580 	u8 *hash_id, *separator;
581 	int i;
582 
583 	len = (get_key_len(img) / 2) - 1;
584 	representative = img->img_encoded_hash_second;
585 	representative[0] = 0;
586 	representative[1] = 1;  /* block type 1 */
587 
588 	padding = &representative[2];
589 	digest = &representative[1] + len - 32;
590 	hash_id = digest - sizeof(hash_identifier);
591 	separator = hash_id - 1;
592 
593 	/* fill padding area pointed by padding with 0xff */
594 	memset(padding, 0xff, separator - padding);
595 
596 	/* fill byte pointed by separator */
597 	*separator = 0;
598 
599 	/* fill SHA-256 DER value  pointed by HashId */
600 	memcpy(hash_id, hash_identifier, sizeof(hash_identifier));
601 
602 	/* fill hash pointed by Digest */
603 	for (i = 0; i < SHA256_BYTES; i++)
604 		digest[i] = hash_val[i];
605 }
606 
607 /*
608  * Reads and validates the ESBC client header.
609  * This function reads key and signature from the ESBC client header.
610  * If Scatter/Gather flag is on, lengths and offsets of images
611  * present as SG entries are also read. This function also checks
612  * whether the header is valid or not.
613  */
614 static int read_validate_esbc_client_header(struct fsl_secboot_img_priv *img)
615 {
616 	char buf[20];
617 	struct fsl_secboot_img_hdr *hdr = &img->hdr;
618 	void *esbc = (u8 *)(uintptr_t)img->ehdrloc;
619 	u8 *k, *s;
620 	u32 ret = 0;
621 
622 #ifdef CONFIG_KEY_REVOCATION
623 #endif
624 	int  key_found = 0;
625 
626 	/* check barker code */
627 	if (memcmp(hdr->barker, barker_code, ESBC_BARKER_LEN))
628 		return ERROR_ESBC_CLIENT_HEADER_BARKER;
629 
630 	/* If Image Address is not passed as argument to function,
631 	 * then Address and Size must be read from the Header.
632 	 */
633 	if (img->img_addr == 0) {
634 	#ifdef CONFIG_ESBC_ADDR_64BIT
635 		img->img_addr = hdr->pimg64;
636 	#else
637 		img->img_addr = hdr->pimg;
638 	#endif
639 	}
640 
641 	sprintf(buf, "%lx", img->img_addr);
642 	setenv("img_addr", buf);
643 
644 	if (!hdr->img_size)
645 		return ERROR_ESBC_CLIENT_HEADER_IMG_SIZE;
646 
647 	img->img_size = hdr->img_size;
648 
649 	/* Key checking*/
650 #ifdef CONFIG_KEY_REVOCATION
651 	if (check_srk(img)) {
652 		ret = read_validate_srk_tbl(img);
653 		if (ret != 0)
654 			return ret;
655 		key_found = 1;
656 	}
657 #endif
658 
659 #if defined(CONFIG_FSL_ISBC_KEY_EXT)
660 	if (!key_found && check_ie(img)) {
661 		ret = read_validate_ie_tbl(img);
662 		if (ret != 0)
663 			return ret;
664 		key_found = 1;
665 	}
666 #endif
667 
668 	if (key_found == 0) {
669 		ret = read_validate_single_key(img);
670 		if (ret != 0)
671 			return ret;
672 		key_found = 1;
673 	}
674 
675 	/* check signaure */
676 	if (get_key_len(img) == 2 * hdr->sign_len) {
677 		/* check signature length */
678 		if (!((hdr->sign_len == KEY_SIZE_BYTES / 4) ||
679 		      (hdr->sign_len == KEY_SIZE_BYTES / 2) ||
680 		      (hdr->sign_len == KEY_SIZE_BYTES)))
681 			return ERROR_ESBC_CLIENT_HEADER_SIG_LEN;
682 	} else {
683 		return ERROR_ESBC_CLIENT_HEADER_KEY_LEN_NOT_TWICE_SIG_LEN;
684 	}
685 
686 	memcpy(&img->img_sign, esbc + hdr->psign, hdr->sign_len);
687 
688 	/* No SG support */
689 	if (hdr->sg_flag)
690 		return ERROR_ESBC_CLIENT_HEADER_SG;
691 
692 	/* modulus most significant bit should be set */
693 	k = (u8 *)&img->img_key;
694 
695 	if ((k[0] & 0x80) == 0)
696 		return ERROR_ESBC_CLIENT_HEADER_KEY_MOD_1;
697 
698 	/* modulus value should be odd */
699 	if ((k[get_key_len(img) / 2 - 1] & 0x1) == 0)
700 		return ERROR_ESBC_CLIENT_HEADER_KEY_MOD_2;
701 
702 	/* Check signature value < modulus value */
703 	s = (u8 *)&img->img_sign;
704 
705 	if (!(memcmp(s, k, hdr->sign_len) < 0))
706 		return ERROR_ESBC_CLIENT_HEADER_SIG_KEY_MOD;
707 
708 	return ESBC_VALID_HDR;
709 }
710 
711 static inline int str2longbe(const char *p, ulong *num)
712 {
713 	char *endptr;
714 	ulong tmp;
715 
716 	if (!p) {
717 		return 0;
718 	} else {
719 		tmp = simple_strtoul(p, &endptr, 16);
720 		if (sizeof(ulong) == 4)
721 			*num = cpu_to_be32(tmp);
722 		else
723 			*num = cpu_to_be64(tmp);
724 	}
725 
726 	return *p != '\0' && *endptr == '\0';
727 }
728 /* Function to calculate the ESBC Image Hash
729  * and hash from Digital signature.
730  * The Two hash's are compared to yield the
731  * result of signature validation.
732  */
733 static int calculate_cmp_img_sig(struct fsl_secboot_img_priv *img)
734 {
735 	int ret;
736 	uint32_t key_len;
737 	struct key_prop prop;
738 #if !defined(USE_HOSTCC)
739 	struct udevice *mod_exp_dev;
740 #endif
741 	ret = calc_esbchdr_esbc_hash(img);
742 	if (ret)
743 		return ret;
744 
745 	/* Construct encoded hash EM' wrt PKCSv1.5 */
746 	construct_img_encoded_hash_second(img);
747 
748 	/* Fill prop structure for public key */
749 	memset(&prop, 0, sizeof(struct key_prop));
750 	key_len = get_key_len(img) / 2;
751 	prop.modulus = img->img_key;
752 	prop.public_exponent = img->img_key + key_len;
753 	prop.num_bits = key_len * 8;
754 	prop.exp_len = key_len;
755 
756 	ret = uclass_get_device(UCLASS_MOD_EXP, 0, &mod_exp_dev);
757 	if (ret) {
758 		printf("RSA: Can't find Modular Exp implementation\n");
759 		return -EINVAL;
760 	}
761 
762 	ret = rsa_mod_exp(mod_exp_dev, img->img_sign, img->hdr.sign_len,
763 			  &prop, img->img_encoded_hash);
764 	if (ret)
765 		return ret;
766 
767 	/*
768 	 * compare the encoded messages EM' and EM wrt RSA PKCSv1.5
769 	 * memcmp returns zero on success
770 	 * memcmp returns non-zero on failure
771 	 */
772 	ret = memcmp(&img->img_encoded_hash_second, &img->img_encoded_hash,
773 		img->hdr.sign_len);
774 
775 	if (ret)
776 		return ERROR_ESBC_CLIENT_HASH_COMPARE_EM;
777 
778 	return 0;
779 }
780 
781 int fsl_secboot_validate(uintptr_t haddr, char *arg_hash_str,
782 			uintptr_t img_addr)
783 {
784 	struct ccsr_sfp_regs *sfp_regs = (void *)(CONFIG_SYS_SFP_ADDR);
785 	ulong hash[SHA256_BYTES/sizeof(ulong)];
786 	char hash_str[NUM_HEX_CHARS + 1];
787 	struct fsl_secboot_img_priv *img;
788 	struct fsl_secboot_img_hdr *hdr;
789 	void *esbc;
790 	int ret, i, hash_cmd = 0;
791 	u32 srk_hash[8];
792 
793 	if (arg_hash_str != NULL) {
794 		const char *cp = arg_hash_str;
795 		int i = 0;
796 
797 		if (*cp == '0' && *(cp + 1) == 'x')
798 			cp += 2;
799 
800 		/* The input string expected is in hex, where
801 		 * each 4 bits would be represented by a hex
802 		 * sha256 hash is 256 bits long, which would mean
803 		 * num of characters = 256 / 4
804 		 */
805 		if (strlen(cp) != SHA256_NIBBLES) {
806 			printf("%s is not a 256 bits hex string as expected\n",
807 			       arg_hash_str);
808 			return -1;
809 		}
810 
811 		for (i = 0; i < sizeof(hash)/sizeof(ulong); i++) {
812 			strncpy(hash_str, cp + (i * NUM_HEX_CHARS),
813 				NUM_HEX_CHARS);
814 			hash_str[NUM_HEX_CHARS] = '\0';
815 			if (!str2longbe(hash_str, &hash[i])) {
816 				printf("%s is not a 256 bits hex string ",
817 				       arg_hash_str);
818 				return -1;
819 			}
820 		}
821 
822 		hash_cmd = 1;
823 	}
824 
825 	img = malloc(sizeof(struct fsl_secboot_img_priv));
826 
827 	if (!img)
828 		return -1;
829 
830 	memset(img, 0, sizeof(struct fsl_secboot_img_priv));
831 
832 	/* Update the information in Private Struct */
833 	hdr = &img->hdr;
834 	img->ehdrloc = haddr;
835 	img->img_addr = img_addr;
836 	esbc = (u8 *)img->ehdrloc;
837 
838 	memcpy(hdr, esbc, sizeof(struct fsl_secboot_img_hdr));
839 
840 	/* read and validate esbc header */
841 	ret = read_validate_esbc_client_header(img);
842 
843 	if (ret != ESBC_VALID_HDR) {
844 		fsl_secboot_handle_error(ret);
845 		goto exit;
846 	}
847 
848 	/* SRKH present in SFP */
849 	for (i = 0; i < NUM_SRKH_REGS; i++)
850 		srk_hash[i] = srk_in32(&sfp_regs->srk_hash[i]);
851 
852 	/*
853 	 * Calculate hash of key obtained via offset present in
854 	 * ESBC uboot client hdr
855 	 */
856 	ret = calc_img_key_hash(img);
857 	if (ret) {
858 		fsl_secblk_handle_error(ret);
859 		goto exit;
860 	}
861 
862 	/* Compare hash obtained above with SRK hash present in SFP */
863 	if (hash_cmd)
864 		ret = memcmp(&hash, &img->img_key_hash, SHA256_BYTES);
865 	else
866 		ret = memcmp(srk_hash, img->img_key_hash, SHA256_BYTES);
867 
868 #if defined(CONFIG_FSL_ISBC_KEY_EXT)
869 	if (!hash_cmd && check_ie(img))
870 		ret = 0;
871 #endif
872 
873 	if (ret != 0) {
874 		fsl_secboot_handle_error(ERROR_ESBC_CLIENT_HASH_COMPARE_KEY);
875 		goto exit;
876 	}
877 
878 	ret = calculate_cmp_img_sig(img);
879 	if (ret) {
880 		fsl_secboot_handle_error(ret);
881 		goto exit;
882 	}
883 
884 exit:
885 	return ret;
886 }
887