xref: /rk3399_rockchip-uboot/lib/rsa/rsa-sign.c (revision 3301aa1a14d90d7ce0b25aeac8abc03fb0311a1d)
1 /*
2  * Copyright (c) 2013, Google Inc.
3  *
4  * SPDX-License-Identifier:	GPL-2.0+
5  */
6 
7 #include "mkimage.h"
8 #include <stdio.h>
9 #include <string.h>
10 #include <image.h>
11 #include <time.h>
12 #include <openssl/bn.h>
13 #include <openssl/rsa.h>
14 #include <openssl/pem.h>
15 #include <openssl/err.h>
16 #include <openssl/ssl.h>
17 #include <openssl/evp.h>
18 #include <openssl/engine.h>
19 
20 #if OPENSSL_VERSION_NUMBER >= 0x10000000L
21 #define HAVE_ERR_REMOVE_THREAD_STATE
22 #endif
23 
24 #if OPENSSL_VERSION_NUMBER < 0x10100000L
25 static void RSA_get0_key(const RSA *r,
26                  const BIGNUM **n, const BIGNUM **e, const BIGNUM **d)
27 {
28    if (n != NULL)
29        *n = r->n;
30    if (e != NULL)
31        *e = r->e;
32    if (d != NULL)
33        *d = r->d;
34 }
35 #endif
36 
37 static int rsa_err(const char *msg)
38 {
39 	unsigned long sslErr = ERR_get_error();
40 
41 	fprintf(stderr, "%s", msg);
42 	fprintf(stderr, ": %s\n",
43 		ERR_error_string(sslErr, 0));
44 
45 	return -1;
46 }
47 
48 /**
49  * rsa_pem_get_pub_key() - read a public key from a .crt file
50  *
51  * @keydir:	Directory containins the key
52  * @name	Name of key file (will have a .crt extension)
53  * @rsap	Returns RSA object, or NULL on failure
54  * @return 0 if ok, -ve on error (in which case *rsap will be set to NULL)
55  */
56 static int rsa_pem_get_pub_key(const char *keydir, const char *name, RSA **rsap)
57 {
58 	char path[1024];
59 	EVP_PKEY *key;
60 	X509 *cert;
61 	RSA *rsa;
62 	FILE *f;
63 	int ret;
64 
65 	*rsap = NULL;
66 	snprintf(path, sizeof(path), "%s/%s.crt", keydir, name);
67 	f = fopen(path, "r");
68 	if (!f) {
69 		fprintf(stderr, "Couldn't open RSA certificate: '%s': %s\n",
70 			path, strerror(errno));
71 		return -EACCES;
72 	}
73 
74 	/* Read the certificate */
75 	cert = NULL;
76 	if (!PEM_read_X509(f, &cert, NULL, NULL)) {
77 		rsa_err("Couldn't read certificate");
78 		ret = -EINVAL;
79 		goto err_cert;
80 	}
81 
82 	/* Get the public key from the certificate. */
83 	key = X509_get_pubkey(cert);
84 	if (!key) {
85 		rsa_err("Couldn't read public key\n");
86 		ret = -EINVAL;
87 		goto err_pubkey;
88 	}
89 
90 	/* Convert to a RSA_style key. */
91 	rsa = EVP_PKEY_get1_RSA(key);
92 	if (!rsa) {
93 		rsa_err("Couldn't convert to a RSA style key");
94 		ret = -EINVAL;
95 		goto err_rsa;
96 	}
97 	fclose(f);
98 	EVP_PKEY_free(key);
99 	X509_free(cert);
100 	*rsap = rsa;
101 
102 	return 0;
103 
104 err_rsa:
105 	EVP_PKEY_free(key);
106 err_pubkey:
107 	X509_free(cert);
108 err_cert:
109 	fclose(f);
110 	return ret;
111 }
112 
113 /**
114  * rsa_engine_get_pub_key() - read a public key from given engine
115  *
116  * @keydir:	Key prefix
117  * @name	Name of key
118  * @engine	Engine to use
119  * @rsap	Returns RSA object, or NULL on failure
120  * @return 0 if ok, -ve on error (in which case *rsap will be set to NULL)
121  */
122 static int rsa_engine_get_pub_key(const char *keydir, const char *name,
123 				  ENGINE *engine, RSA **rsap)
124 {
125 	const char *engine_id;
126 	char key_id[1024];
127 	EVP_PKEY *key;
128 	RSA *rsa;
129 	int ret;
130 
131 	*rsap = NULL;
132 
133 	engine_id = ENGINE_get_id(engine);
134 
135 	if (engine_id && !strcmp(engine_id, "pkcs11")) {
136 		if (keydir)
137 			snprintf(key_id, sizeof(key_id),
138 				 "pkcs11:%s;object=%s;type=public",
139 				 keydir, name);
140 		else
141 			snprintf(key_id, sizeof(key_id),
142 				 "pkcs11:object=%s;type=public",
143 				 name);
144 	} else {
145 		fprintf(stderr, "Engine not supported\n");
146 		return -ENOTSUP;
147 	}
148 
149 	key = ENGINE_load_public_key(engine, key_id, NULL, NULL);
150 	if (!key)
151 		return rsa_err("Failure loading public key from engine");
152 
153 	/* Convert to a RSA_style key. */
154 	rsa = EVP_PKEY_get1_RSA(key);
155 	if (!rsa) {
156 		rsa_err("Couldn't convert to a RSA style key");
157 		ret = -EINVAL;
158 		goto err_rsa;
159 	}
160 
161 	EVP_PKEY_free(key);
162 	*rsap = rsa;
163 
164 	return 0;
165 
166 err_rsa:
167 	EVP_PKEY_free(key);
168 	return ret;
169 }
170 
171 /**
172  * rsa_get_pub_key() - read a public key
173  *
174  * @keydir:	Directory containing the key (PEM file) or key prefix (engine)
175  * @name	Name of key file (will have a .crt extension)
176  * @engine	Engine to use
177  * @rsap	Returns RSA object, or NULL on failure
178  * @return 0 if ok, -ve on error (in which case *rsap will be set to NULL)
179  */
180 static int rsa_get_pub_key(const char *keydir, const char *name,
181 			   ENGINE *engine, RSA **rsap)
182 {
183 	if (engine)
184 		return rsa_engine_get_pub_key(keydir, name, engine, rsap);
185 	return rsa_pem_get_pub_key(keydir, name, rsap);
186 }
187 
188 /**
189  * rsa_pem_get_priv_key() - read a private key from a .key file
190  *
191  * @keydir:	Directory containing the key
192  * @name	Name of key file (will have a .key extension)
193  * @rsap	Returns RSA object, or NULL on failure
194  * @return 0 if ok, -ve on error (in which case *rsap will be set to NULL)
195  */
196 static int rsa_pem_get_priv_key(const char *keydir, const char *name,
197 				RSA **rsap)
198 {
199 	char path[1024];
200 	RSA *rsa;
201 	FILE *f;
202 
203 	*rsap = NULL;
204 	snprintf(path, sizeof(path), "%s/%s.key", keydir, name);
205 	f = fopen(path, "r");
206 	if (!f) {
207 		fprintf(stderr, "Couldn't open RSA private key: '%s': %s\n",
208 			path, strerror(errno));
209 		return -ENOENT;
210 	}
211 
212 	rsa = PEM_read_RSAPrivateKey(f, 0, NULL, path);
213 	if (!rsa) {
214 		rsa_err("Failure reading private key");
215 		fclose(f);
216 		return -EPROTO;
217 	}
218 	fclose(f);
219 	*rsap = rsa;
220 
221 	return 0;
222 }
223 
224 /**
225  * rsa_engine_get_priv_key() - read a private key from given engine
226  *
227  * @keydir:	Key prefix
228  * @name	Name of key
229  * @engine	Engine to use
230  * @rsap	Returns RSA object, or NULL on failure
231  * @return 0 if ok, -ve on error (in which case *rsap will be set to NULL)
232  */
233 static int rsa_engine_get_priv_key(const char *keydir, const char *name,
234 				   ENGINE *engine, RSA **rsap)
235 {
236 	const char *engine_id;
237 	char key_id[1024];
238 	EVP_PKEY *key;
239 	RSA *rsa;
240 	int ret;
241 
242 	*rsap = NULL;
243 
244 	engine_id = ENGINE_get_id(engine);
245 
246 	if (engine_id && !strcmp(engine_id, "pkcs11")) {
247 		if (keydir)
248 			snprintf(key_id, sizeof(key_id),
249 				 "pkcs11:%s;object=%s;type=private",
250 				 keydir, name);
251 		else
252 			snprintf(key_id, sizeof(key_id),
253 				 "pkcs11:object=%s;type=private",
254 				 name);
255 	} else {
256 		fprintf(stderr, "Engine not supported\n");
257 		return -ENOTSUP;
258 	}
259 
260 	key = ENGINE_load_private_key(engine, key_id, NULL, NULL);
261 	if (!key)
262 		return rsa_err("Failure loading private key from engine");
263 
264 	/* Convert to a RSA_style key. */
265 	rsa = EVP_PKEY_get1_RSA(key);
266 	if (!rsa) {
267 		rsa_err("Couldn't convert to a RSA style key");
268 		ret = -EINVAL;
269 		goto err_rsa;
270 	}
271 
272 	EVP_PKEY_free(key);
273 	*rsap = rsa;
274 
275 	return 0;
276 
277 err_rsa:
278 	EVP_PKEY_free(key);
279 	return ret;
280 }
281 
282 /**
283  * rsa_get_priv_key() - read a private key
284  *
285  * @keydir:	Directory containing the key (PEM file) or key prefix (engine)
286  * @name	Name of key
287  * @engine	Engine to use for signing
288  * @rsap	Returns RSA object, or NULL on failure
289  * @return 0 if ok, -ve on error (in which case *rsap will be set to NULL)
290  */
291 static int rsa_get_priv_key(const char *keydir, const char *name,
292 			    ENGINE *engine, RSA **rsap)
293 {
294 	if (engine)
295 		return rsa_engine_get_priv_key(keydir, name, engine, rsap);
296 	return rsa_pem_get_priv_key(keydir, name, rsap);
297 }
298 
299 static int rsa_init(void)
300 {
301 	int ret;
302 
303 #if OPENSSL_VERSION_NUMBER < 0x10100000L
304 	ret = SSL_library_init();
305 #else
306 	ret = OPENSSL_init_ssl(0, NULL);
307 #endif
308 	if (!ret) {
309 		fprintf(stderr, "Failure to init SSL library\n");
310 		return -1;
311 	}
312 #if OPENSSL_VERSION_NUMBER < 0x10100000L
313 	SSL_load_error_strings();
314 
315 	OpenSSL_add_all_algorithms();
316 	OpenSSL_add_all_digests();
317 	OpenSSL_add_all_ciphers();
318 #endif
319 
320 	return 0;
321 }
322 
323 static int rsa_engine_init(const char *engine_id, ENGINE **pe)
324 {
325 	ENGINE *e;
326 	int ret;
327 
328 	ENGINE_load_builtin_engines();
329 
330 	e = ENGINE_by_id(engine_id);
331 	if (!e) {
332 		fprintf(stderr, "Engine isn't available\n");
333 		ret = -1;
334 		goto err_engine_by_id;
335 	}
336 
337 	if (!ENGINE_init(e)) {
338 		fprintf(stderr, "Couldn't initialize engine\n");
339 		ret = -1;
340 		goto err_engine_init;
341 	}
342 
343 	if (!ENGINE_set_default_RSA(e)) {
344 		fprintf(stderr, "Couldn't set engine as default for RSA\n");
345 		ret = -1;
346 		goto err_set_rsa;
347 	}
348 
349 	*pe = e;
350 
351 	return 0;
352 
353 err_set_rsa:
354 	ENGINE_finish(e);
355 err_engine_init:
356 	ENGINE_free(e);
357 err_engine_by_id:
358 #if OPENSSL_VERSION_NUMBER < 0x10100000L
359 	ENGINE_cleanup();
360 #endif
361 	return ret;
362 }
363 
364 static void rsa_remove(void)
365 {
366 #if OPENSSL_VERSION_NUMBER < 0x10100000L
367 	CRYPTO_cleanup_all_ex_data();
368 	ERR_free_strings();
369 #ifdef HAVE_ERR_REMOVE_THREAD_STATE
370 	ERR_remove_thread_state(NULL);
371 #else
372 	ERR_remove_state(0);
373 #endif
374 	EVP_cleanup();
375 #endif
376 }
377 
378 static void rsa_engine_remove(ENGINE *e)
379 {
380 	if (e) {
381 		ENGINE_finish(e);
382 		ENGINE_free(e);
383 	}
384 }
385 
386 /*
387  * With this data2sign.bin, we can provide it to who real holds the RAS-private
388  * key to sign current fit image. Then we replace the signature in fit image
389  * with a valid one.
390  */
391 static void gen_data2sign(const struct image_region region[], int region_count)
392 {
393 	char *file = "data2sign.bin";
394 	FILE *fd;
395 	int i;
396 
397 	fd = fopen(file, "wb");
398 	if (!fd) {
399 		fprintf(stderr, "Failed to create %s: %s\n",
400 			file, strerror(errno));
401 		return -ENOENT;
402 	}
403 
404 	for (i = 0; i < region_count; i++)
405 		fwrite(region[i].data, region[i].size, 1, fd);
406 
407 	fclose(fd);
408 }
409 
410 static int rsa_sign_with_key(RSA *rsa, struct checksum_algo *checksum_algo,
411 		const struct image_region region[], int region_count,
412 		uint8_t **sigp, uint *sig_size)
413 {
414 	EVP_PKEY *key;
415 	EVP_MD_CTX *context;
416 	int size, ret = 0;
417 	uint8_t *sig;
418 	int i;
419 
420 	key = EVP_PKEY_new();
421 	if (!key)
422 		return rsa_err("EVP_PKEY object creation failed");
423 
424 	if (!EVP_PKEY_set1_RSA(key, rsa)) {
425 		ret = rsa_err("EVP key setup failed");
426 		goto err_set;
427 	}
428 
429 	size = EVP_PKEY_size(key);
430 	sig = malloc(size);
431 	if (!sig) {
432 		fprintf(stderr, "Out of memory for signature (%d bytes)\n",
433 			size);
434 		ret = -ENOMEM;
435 		goto err_alloc;
436 	}
437 
438 	context = EVP_MD_CTX_create();
439 	if (!context) {
440 		ret = rsa_err("EVP context creation failed");
441 		goto err_create;
442 	}
443 	EVP_MD_CTX_init(context);
444 	if (!EVP_SignInit(context, checksum_algo->calculate_sign())) {
445 		ret = rsa_err("Signer setup failed");
446 		goto err_sign;
447 	}
448 
449 	for (i = 0; i < region_count; i++) {
450 		if (!EVP_SignUpdate(context, region[i].data, region[i].size)) {
451 			ret = rsa_err("Signing data failed");
452 			goto err_sign;
453 		}
454 	}
455 
456 	if (!EVP_SignFinal(context, sig, sig_size, key)) {
457 		ret = rsa_err("Could not obtain signature");
458 		goto err_sign;
459 	}
460 	#if OPENSSL_VERSION_NUMBER < 0x10100000L
461 		EVP_MD_CTX_cleanup(context);
462 	#else
463 		EVP_MD_CTX_reset(context);
464 	#endif
465 	EVP_MD_CTX_destroy(context);
466 	EVP_PKEY_free(key);
467 
468 	debug("Got signature: %d bytes, expected %d\n", *sig_size, size);
469 	*sigp = sig;
470 	*sig_size = size;
471 
472 	gen_data2sign(region, region_count);
473 
474 	return 0;
475 
476 err_sign:
477 	EVP_MD_CTX_destroy(context);
478 err_create:
479 	free(sig);
480 err_alloc:
481 err_set:
482 	EVP_PKEY_free(key);
483 	return ret;
484 }
485 
486 int rsa_sign(struct image_sign_info *info,
487 	     const struct image_region region[], int region_count,
488 	     uint8_t **sigp, uint *sig_len)
489 {
490 	RSA *rsa;
491 	ENGINE *e = NULL;
492 	int ret;
493 
494 	ret = rsa_init();
495 	if (ret)
496 		return ret;
497 
498 	if (info->engine_id) {
499 		ret = rsa_engine_init(info->engine_id, &e);
500 		if (ret)
501 			goto err_engine;
502 	}
503 
504 	ret = rsa_get_priv_key(info->keydir, info->keyname, e, &rsa);
505 	if (ret)
506 		goto err_priv;
507 	ret = rsa_sign_with_key(rsa, info->checksum, region,
508 				region_count, sigp, sig_len);
509 	if (ret)
510 		goto err_sign;
511 
512 	RSA_free(rsa);
513 	if (info->engine_id)
514 		rsa_engine_remove(e);
515 	rsa_remove();
516 
517 	return ret;
518 
519 err_sign:
520 	RSA_free(rsa);
521 err_priv:
522 	if (info->engine_id)
523 		rsa_engine_remove(e);
524 err_engine:
525 	rsa_remove();
526 	return ret;
527 }
528 
529 /*
530  * rsa_get_exponent(): - Get the public exponent from an RSA key
531  */
532 static int rsa_get_exponent(RSA *key, uint64_t *e)
533 {
534 	int ret;
535 	BIGNUM *bn_te;
536 	const BIGNUM *key_e;
537 	uint64_t te;
538 
539 	ret = -EINVAL;
540 	bn_te = NULL;
541 
542 	if (!e)
543 		goto cleanup;
544 
545 	RSA_get0_key(key, NULL, &key_e, NULL);
546 	if (BN_num_bits(key_e) > 64)
547 		goto cleanup;
548 
549 	*e = BN_get_word(key_e);
550 
551 	if (BN_num_bits(key_e) < 33) {
552 		ret = 0;
553 		goto cleanup;
554 	}
555 
556 	bn_te = BN_dup(key_e);
557 	if (!bn_te)
558 		goto cleanup;
559 
560 	if (!BN_rshift(bn_te, bn_te, 32))
561 		goto cleanup;
562 
563 	if (!BN_mask_bits(bn_te, 32))
564 		goto cleanup;
565 
566 	te = BN_get_word(bn_te);
567 	te <<= 32;
568 	*e |= te;
569 	ret = 0;
570 
571 cleanup:
572 	if (bn_te)
573 		BN_free(bn_te);
574 
575 	return ret;
576 }
577 
578 /*
579  * rsa_get_params(): - Get the important parameters of an RSA public key
580  */
581 int rsa_get_params(RSA *key, uint64_t *exponent, uint32_t *n0_invp,
582 		   BIGNUM **modulusp, BIGNUM **exponent_BN, BIGNUM **r_squaredp,
583 		   BIGNUM **c_factorp, BIGNUM **np_factorp)
584 {
585 	BIGNUM *big1, *big2, *big32, *big2_32, *big4100, *big2180;
586 	BIGNUM *n, *e, *r, *r_squared, *tmp, *c_factor, *np_factor;
587 	const BIGNUM *key_n, *key_e;
588 	BN_CTX *bn_ctx = BN_CTX_new();
589 	int ret = 0;
590 
591 	/* Initialize BIGNUMs */
592 	big1 = BN_new();
593 	big2 = BN_new();
594 	big32 = BN_new();
595 	big4100 = BN_new();
596 	big2180 = BN_new();
597 
598 	r = BN_new();
599 	r_squared = BN_new();
600 	c_factor = BN_new();
601 	np_factor = BN_new();
602 	tmp = BN_new();
603 	big2_32 = BN_new();
604 	n = BN_new();
605 	e = BN_new();
606 	if (!big1 || !big2 || !big32 || !big4100 || !big2180 || !r ||
607 	    !r_squared || !tmp || !big2_32 || !n || !e ||
608 	    !c_factor || !np_factor) {
609 		fprintf(stderr, "Out of memory (bignum)\n");
610 		return -ENOMEM;
611 	}
612 
613 	if (0 != rsa_get_exponent(key, exponent))
614 		ret = -1;
615 
616 	RSA_get0_key(key, &key_n, &key_e, NULL);
617 	if (!BN_copy(n, key_n) || !BN_copy(e, key_e) ||
618 	    !BN_set_word(big1, 1L) ||
619 	    !BN_set_word(big2, 2L) || !BN_set_word(big32, 32L) ||
620 	    !BN_set_word(big4100, 4100L) || !BN_set_word(big2180, 2180L))
621 		ret = -1;
622 
623 	/* big2_32 = 2^32 */
624 	if (!BN_exp(big2_32, big2, big32, bn_ctx))
625 		ret = -1;
626 
627 	/* Calculate n0_inv = -1 / n[0] mod 2^32 */
628 	if (!BN_mod_inverse(tmp, n, big2_32, bn_ctx) ||
629 	    !BN_sub(tmp, big2_32, tmp))
630 		ret = -1;
631 	*n0_invp = BN_get_word(tmp);
632 
633 	/* Calculate R = 2^(# of key bits) */
634 	if (!BN_set_word(tmp, BN_num_bits(n)) ||
635 	    !BN_exp(r, big2, tmp, bn_ctx))
636 		ret = -1;
637 
638 	/* Calculate r_squared = R^2 mod n */
639 	if (!BN_copy(r_squared, r) ||
640 	    !BN_mul(tmp, r_squared, r, bn_ctx) ||
641 	    !BN_mod(r_squared, tmp, n, bn_ctx))
642 		ret = -1;
643 
644 	/* Calculate c_factor = 2^4100 mod n */
645 	if (!BN_exp(tmp, big2, big4100, bn_ctx) ||
646 	    !BN_mod(c_factor, tmp, n, bn_ctx))
647 		ret = -1;
648 
649 	/* Calculate np_factor = 2^2180 div n */
650 	if (!BN_exp(tmp, big2, big2180, bn_ctx) ||
651 	    !BN_div(np_factor, NULL, tmp, n, bn_ctx))
652 		ret = -1;
653 
654 	*modulusp = n;
655 	*exponent_BN = e;
656 	*r_squaredp = r_squared;
657 	*c_factorp = c_factor;
658 	*np_factorp = np_factor;
659 
660 	BN_free(big1);
661 	BN_free(big2);
662 	BN_free(big32);
663 	BN_free(big4100);
664 	BN_free(big2180);
665 	BN_free(r);
666 	BN_free(tmp);
667 	BN_free(big2_32);
668 	if (ret) {
669 		fprintf(stderr, "Bignum operations failed\n");
670 		return -ENOMEM;
671 	}
672 
673 	return ret;
674 }
675 
676 static int fdt_add_bignum(void *blob, int noffset, const char *prop_name,
677 			  BIGNUM *num, int num_bits)
678 {
679 	int nwords = num_bits / 32;
680 	int size;
681 	uint32_t *buf, *ptr;
682 	BIGNUM *tmp, *big2, *big32, *big2_32;
683 	BN_CTX *ctx;
684 	int ret;
685 
686 	tmp = BN_new();
687 	big2 = BN_new();
688 	big32 = BN_new();
689 	big2_32 = BN_new();
690 	if (!tmp || !big2 || !big32 || !big2_32) {
691 		fprintf(stderr, "Out of memory (bignum)\n");
692 		return -ENOMEM;
693 	}
694 	ctx = BN_CTX_new();
695 	if (!tmp) {
696 		fprintf(stderr, "Out of memory (bignum context)\n");
697 		return -ENOMEM;
698 	}
699 	BN_set_word(big2, 2L);
700 	BN_set_word(big32, 32L);
701 	BN_exp(big2_32, big2, big32, ctx); /* B = 2^32 */
702 
703 	size = nwords * sizeof(uint32_t);
704 	buf = malloc(size);
705 	if (!buf) {
706 		fprintf(stderr, "Out of memory (%d bytes)\n", size);
707 		return -ENOMEM;
708 	}
709 
710 	/* Write out modulus as big endian array of integers */
711 	for (ptr = buf + nwords - 1; ptr >= buf; ptr--) {
712 		BN_mod(tmp, num, big2_32, ctx); /* n = N mod B */
713 		*ptr = cpu_to_fdt32(BN_get_word(tmp));
714 		BN_rshift(num, num, 32); /*  N = N/B */
715 	}
716 
717 	/*
718 	 * We try signing with successively increasing size values, so this
719 	 * might fail several times
720 	 */
721 	ret = fdt_setprop(blob, noffset, prop_name, buf, size);
722 	if (ret)
723 		return -FDT_ERR_NOSPACE;
724 	free(buf);
725 	BN_free(tmp);
726 	BN_free(big2);
727 	BN_free(big32);
728 	BN_free(big2_32);
729 
730 	return ret;
731 }
732 
733 int rsa_add_verify_data(struct image_sign_info *info, void *keydest)
734 {
735 	BIGNUM *modulus, *exponent_BN, *r_squared, *c_factor, *np_factor;
736 	uint64_t exponent;
737 	uint32_t n0_inv;
738 	int parent, node;
739 	char name[100];
740 	int ret;
741 	int bits;
742 	RSA *rsa;
743 	ENGINE *e = NULL;
744 
745 	debug("%s: Getting verification data\n", __func__);
746 	if (info->engine_id) {
747 		ret = rsa_engine_init(info->engine_id, &e);
748 		if (ret)
749 			return ret;
750 	}
751 	ret = rsa_get_pub_key(info->keydir, info->keyname, e, &rsa);
752 	if (ret)
753 		goto err_get_pub_key;
754 	ret = rsa_get_params(rsa, &exponent, &n0_inv, &modulus,
755 			     &exponent_BN, &r_squared, &c_factor, &np_factor);
756 	if (ret)
757 		goto err_get_params;
758 	bits = BN_num_bits(modulus);
759 	parent = fdt_subnode_offset(keydest, 0, FIT_SIG_NODENAME);
760 	if (parent == -FDT_ERR_NOTFOUND) {
761 		parent = fdt_add_subnode(keydest, 0, FIT_SIG_NODENAME);
762 		if (parent < 0) {
763 			ret = parent;
764 			if (ret != -FDT_ERR_NOSPACE) {
765 				fprintf(stderr, "Couldn't create signature node: %s\n",
766 					fdt_strerror(parent));
767 			}
768 		}
769 	}
770 	if (ret)
771 		goto done;
772 
773 	/* Either create or overwrite the named key node */
774 	snprintf(name, sizeof(name), "key-%s", info->keyname);
775 	node = fdt_subnode_offset(keydest, parent, name);
776 	if (node == -FDT_ERR_NOTFOUND) {
777 		node = fdt_add_subnode(keydest, parent, name);
778 		if (node < 0) {
779 			ret = node;
780 			if (ret != -FDT_ERR_NOSPACE) {
781 				fprintf(stderr, "Could not create key subnode: %s\n",
782 					fdt_strerror(node));
783 			}
784 		}
785 	} else if (node < 0) {
786 		fprintf(stderr, "Cannot select keys parent: %s\n",
787 			fdt_strerror(node));
788 		ret = node;
789 	}
790 
791 	if (!ret) {
792 		ret = fdt_setprop_string(keydest, node, "key-name-hint",
793 				 info->keyname);
794 	}
795 	if (!ret)
796 		ret = fdt_setprop_u32(keydest, node, "rsa,num-bits", bits);
797 	if (!ret)
798 		ret = fdt_setprop_u32(keydest, node, "rsa,n0-inverse", n0_inv);
799 	if (!ret) {
800 		ret = fdt_setprop_u64(keydest, node, "rsa,exponent", exponent);
801 	}
802 	if (!ret) {
803 		ret = fdt_add_bignum(keydest, node, "rsa,exponent-BN",
804 				     exponent_BN, bits);
805 	}
806 	if (!ret) {
807 		ret = fdt_add_bignum(keydest, node, "rsa,modulus", modulus,
808 				     bits);
809 	}
810 	if (!ret) {
811 		ret = fdt_add_bignum(keydest, node, "rsa,r-squared", r_squared,
812 				     bits);
813 	}
814 	if (!ret) {
815 		ret = fdt_add_bignum(keydest, node, "rsa,c", c_factor,
816 				     bits);
817 	}
818 	if (!ret) {
819 		ret = fdt_add_bignum(keydest, node, "rsa,np", np_factor,
820 				     bits);
821 	}
822 	if (!ret) {
823 		ret = fdt_setprop_string(keydest, node, FIT_ALGO_PROP,
824 					 info->name);
825 	}
826 	if (!ret && info->require_keys) {
827 		ret = fdt_setprop_string(keydest, node, "required",
828 					 info->require_keys);
829 	}
830 done:
831 	BN_free(modulus);
832 	BN_free(r_squared);
833 	if (ret)
834 		ret = ret == -FDT_ERR_NOSPACE ? -ENOSPC : -EIO;
835 err_get_params:
836 	RSA_free(rsa);
837 err_get_pub_key:
838 	if (info->engine_id)
839 		rsa_engine_remove(e);
840 
841 	return ret;
842 }
843