xref: /openbmc/u-boot/common/image-sig.c (revision 3ba98ed8)
1 // SPDX-License-Identifier: GPL-2.0+
2 /*
3  * Copyright (c) 2013, Google Inc.
4  */
5 
6 #ifdef USE_HOSTCC
7 #include "mkimage.h"
8 #include <time.h>
9 #else
10 #include <common.h>
11 #include <malloc.h>
12 DECLARE_GLOBAL_DATA_PTR;
13 #endif /* !USE_HOSTCC*/
14 #include <image.h>
15 #include <u-boot/rsa.h>
16 #include <u-boot/rsa-checksum.h>
17 
18 #define IMAGE_MAX_HASHED_NODES		100
19 
20 #ifdef USE_HOSTCC
21 void *host_blob;
22 void image_set_host_blob(void *blob)
23 {
24 	host_blob = blob;
25 }
26 void *image_get_host_blob(void)
27 {
28 	return host_blob;
29 }
30 #endif
31 
32 struct checksum_algo checksum_algos[] = {
33 	{
34 		.name = "sha1",
35 		.checksum_len = SHA1_SUM_LEN,
36 		.der_len = SHA1_DER_LEN,
37 		.der_prefix = sha1_der_prefix,
38 #if IMAGE_ENABLE_SIGN
39 		.calculate_sign = EVP_sha1,
40 #endif
41 		.calculate = hash_calculate,
42 	},
43 	{
44 		.name = "sha256",
45 		.checksum_len = SHA256_SUM_LEN,
46 		.der_len = SHA256_DER_LEN,
47 		.der_prefix = sha256_der_prefix,
48 #if IMAGE_ENABLE_SIGN
49 		.calculate_sign = EVP_sha256,
50 #endif
51 		.calculate = hash_calculate,
52 	},
53 #ifdef CONFIG_SHA384
54 	{
55 		.name = "sha384",
56 		.checksum_len = SHA384_SUM_LEN,
57 		.der_len = SHA384_DER_LEN,
58 		.der_prefix = sha384_der_prefix,
59 #if IMAGE_ENABLE_SIGN
60 		.calculate_sign = EVP_sha384,
61 #endif
62 		.calculate = hash_calculate,
63 	},
64 #endif
65 #ifdef CONFIG_SHA512
66 	{
67 		.name = "sha512",
68 		.checksum_len = SHA512_SUM_LEN,
69 		.der_len = SHA512_DER_LEN,
70 		.der_prefix = sha512_der_prefix,
71 #if IMAGE_ENABLE_SIGN
72 		.calculate_sign = EVP_sha512,
73 #endif
74 		.calculate = hash_calculate,
75 	},
76 #endif
77 
78 };
79 
80 struct crypto_algo crypto_algos[] = {
81 	{
82 		.name = "rsa2048",
83 		.key_len = RSA2048_BYTES,
84 		.sign = rsa_sign,
85 		.add_verify_data = rsa_add_verify_data,
86 		.verify = rsa_verify,
87 	},
88 	{
89 		.name = "rsa3072",
90 		.key_len = RSA3072_BYTES,
91 		.sign = rsa_sign,
92 		.add_verify_data = rsa_add_verify_data,
93 		.verify = rsa_verify,
94 	},
95 	{
96 		.name = "rsa4096",
97 		.key_len = RSA4096_BYTES,
98 		.sign = rsa_sign,
99 		.add_verify_data = rsa_add_verify_data,
100 		.verify = rsa_verify,
101 	}
102 
103 };
104 
105 struct padding_algo padding_algos[] = {
106 	{
107 		.name = "pkcs-1.5",
108 		.verify = padding_pkcs_15_verify,
109 	},
110 #ifdef CONFIG_FIT_ENABLE_RSASSA_PSS_SUPPORT
111 	{
112 		.name = "pss",
113 		.verify = padding_pss_verify,
114 	}
115 #endif /* CONFIG_FIT_ENABLE_RSASSA_PSS_SUPPORT */
116 };
117 
118 struct checksum_algo *image_get_checksum_algo(const char *full_name)
119 {
120 	int i;
121 	const char *name;
122 
123 	for (i = 0; i < ARRAY_SIZE(checksum_algos); i++) {
124 		name = checksum_algos[i].name;
125 		/* Make sure names match and next char is a comma */
126 		if (!strncmp(name, full_name, strlen(name)) &&
127 		    full_name[strlen(name)] == ',')
128 			return &checksum_algos[i];
129 	}
130 
131 	return NULL;
132 }
133 
134 struct crypto_algo *image_get_crypto_algo(const char *full_name)
135 {
136 	int i;
137 	const char *name;
138 
139 	/* Move name to after the comma */
140 	name = strchr(full_name, ',');
141 	if (!name)
142 		return NULL;
143 	name += 1;
144 
145 	for (i = 0; i < ARRAY_SIZE(crypto_algos); i++) {
146 		if (!strcmp(crypto_algos[i].name, name))
147 			return &crypto_algos[i];
148 	}
149 
150 	return NULL;
151 }
152 
153 struct padding_algo *image_get_padding_algo(const char *name)
154 {
155 	int i;
156 
157 	if (!name)
158 		return NULL;
159 
160 	for (i = 0; i < ARRAY_SIZE(padding_algos); i++) {
161 		if (!strcmp(padding_algos[i].name, name))
162 			return &padding_algos[i];
163 	}
164 
165 	return NULL;
166 }
167 
168 /**
169  * fit_region_make_list() - Make a list of image regions
170  *
171  * Given a list of fdt_regions, create a list of image_regions. This is a
172  * simple conversion routine since the FDT and image code use different
173  * structures.
174  *
175  * @fit: FIT image
176  * @fdt_regions: Pointer to FDT regions
177  * @count: Number of FDT regions
178  * @region: Pointer to image regions, which must hold @count records. If
179  * region is NULL, then (except for an SPL build) the array will be
180  * allocated.
181  * @return: Pointer to image regions
182  */
183 struct image_region *fit_region_make_list(const void *fit,
184 		struct fdt_region *fdt_regions, int count,
185 		struct image_region *region)
186 {
187 	int i;
188 
189 	debug("Hash regions:\n");
190 	debug("%10s %10s\n", "Offset", "Size");
191 
192 	/*
193 	 * Use malloc() except in SPL (to save code size). In SPL the caller
194 	 * must allocate the array.
195 	 */
196 #ifndef CONFIG_SPL_BUILD
197 	if (!region)
198 		region = calloc(sizeof(*region), count);
199 #endif
200 	if (!region)
201 		return NULL;
202 	for (i = 0; i < count; i++) {
203 		debug("%10x %10x\n", fdt_regions[i].offset,
204 		      fdt_regions[i].size);
205 		region[i].data = fit + fdt_regions[i].offset;
206 		region[i].size = fdt_regions[i].size;
207 	}
208 
209 	return region;
210 }
211 
212 static int fit_image_setup_verify(struct image_sign_info *info,
213 		const void *fit, int noffset, int required_keynode,
214 		char **err_msgp)
215 {
216 	char *algo_name;
217 	const char *padding_name;
218 
219 	if (fdt_totalsize(fit) > CONFIG_FIT_SIGNATURE_MAX_SIZE) {
220 		*err_msgp = "Total size too large";
221 		return 1;
222 	}
223 
224 	if (fit_image_hash_get_algo(fit, noffset, &algo_name)) {
225 		*err_msgp = "Can't get hash algo property";
226 		return -1;
227 	}
228 
229 	padding_name = fdt_getprop(fit, noffset, "padding", NULL);
230 	if (!padding_name)
231 		padding_name = RSA_DEFAULT_PADDING_NAME;
232 
233 	memset(info, '\0', sizeof(*info));
234 	info->keyname = fdt_getprop(fit, noffset, "key-name-hint", NULL);
235 	info->fit = (void *)fit;
236 	info->node_offset = noffset;
237 	info->name = algo_name;
238 	info->checksum = image_get_checksum_algo(algo_name);
239 	info->crypto = image_get_crypto_algo(algo_name);
240 	info->padding = image_get_padding_algo(padding_name);
241 	info->fdt_blob = gd_fdt_blob();
242 	info->required_keynode = required_keynode;
243 	printf("%s:%s", algo_name, info->keyname);
244 
245 	if (!info->checksum || !info->crypto || !info->padding) {
246 		*err_msgp = "Unknown signature algorithm";
247 		return -1;
248 	}
249 
250 	return 0;
251 }
252 
253 int fit_image_check_sig(const void *fit, int noffset, const void *data,
254 		size_t size, int required_keynode, char **err_msgp)
255 {
256 	struct image_sign_info info;
257 	struct image_region region;
258 	uint8_t *fit_value;
259 	int fit_value_len;
260 
261 	*err_msgp = NULL;
262 	if (fit_image_setup_verify(&info, fit, noffset, required_keynode,
263 				   err_msgp))
264 		return -1;
265 
266 	if (fit_image_hash_get_value(fit, noffset, &fit_value,
267 				     &fit_value_len)) {
268 		*err_msgp = "Can't get hash value property";
269 		return -1;
270 	}
271 
272 	region.data = data;
273 	region.size = size;
274 
275 	if (info.crypto->verify(&info, &region, 1, fit_value, fit_value_len)) {
276 		*err_msgp = "Verification failed";
277 		return -1;
278 	}
279 
280 	return 0;
281 }
282 
283 static int fit_image_verify_sig(const void *fit, int image_noffset,
284 		const char *data, size_t size, const void *sig_blob,
285 		int sig_offset)
286 {
287 	int noffset;
288 	char *err_msg = "";
289 	int verified = 0;
290 	int ret;
291 
292 	/* Process all hash subnodes of the component image node */
293 	fdt_for_each_subnode(noffset, fit, image_noffset) {
294 		const char *name = fit_get_name(fit, noffset, NULL);
295 
296 		if (!strncmp(name, FIT_SIG_NODENAME,
297 			     strlen(FIT_SIG_NODENAME))) {
298 			ret = fit_image_check_sig(fit, noffset, data,
299 							size, -1, &err_msg);
300 			if (ret) {
301 				puts("- ");
302 			} else {
303 				puts("+ ");
304 				verified = 1;
305 				break;
306 			}
307 		}
308 	}
309 
310 	if (noffset == -FDT_ERR_TRUNCATED || noffset == -FDT_ERR_BADSTRUCTURE) {
311 		err_msg = "Corrupted or truncated tree";
312 		goto error;
313 	}
314 
315 	return verified ? 0 : -EPERM;
316 
317 error:
318 	printf(" error!\n%s for '%s' hash node in '%s' image node\n",
319 	       err_msg, fit_get_name(fit, noffset, NULL),
320 	       fit_get_name(fit, image_noffset, NULL));
321 	return -1;
322 }
323 
324 int fit_image_verify_required_sigs(const void *fit, int image_noffset,
325 		const char *data, size_t size, const void *sig_blob,
326 		int *no_sigsp)
327 {
328 	int verify_count = 0;
329 	int noffset;
330 	int sig_node;
331 
332 	/* Work out what we need to verify */
333 	*no_sigsp = 1;
334 	sig_node = fdt_subnode_offset(sig_blob, 0, FIT_SIG_NODENAME);
335 	if (sig_node < 0) {
336 		debug("%s: No signature node found: %s\n", __func__,
337 		      fdt_strerror(sig_node));
338 		return 0;
339 	}
340 
341 	fdt_for_each_subnode(noffset, sig_blob, sig_node) {
342 		const char *required;
343 		int ret;
344 
345 		required = fdt_getprop(sig_blob, noffset, "required", NULL);
346 		if (!required || strcmp(required, "image"))
347 			continue;
348 		ret = fit_image_verify_sig(fit, image_noffset, data, size,
349 					sig_blob, noffset);
350 		if (ret) {
351 			printf("Failed to verify required signature '%s'\n",
352 			       fit_get_name(sig_blob, noffset, NULL));
353 			return ret;
354 		}
355 		verify_count++;
356 	}
357 
358 	if (verify_count)
359 		*no_sigsp = 0;
360 
361 	return 0;
362 }
363 
364 /**
365  * fit_config_check_sig() - Check the signature of a config
366  *
367  * @fit: FIT to check
368  * @noffset: Offset of configuration node (e.g. /configurations/conf-1)
369  * @required_keynode:	Offset in the control FDT of the required key node,
370  *			if any. If this is given, then the configuration wil not
371  *			pass verification unless that key is used. If this is
372  *			-1 then any signature will do.
373  * @conf_noffset: Offset of the configuration subnode being checked (e.g.
374  *	 /configurations/conf-1/kernel)
375  * @err_msgp:		In the event of an error, this will be pointed to a
376  *			help error string to display to the user.
377  * @return 0 if all verified ok, <0 on error
378  */
379 static int fit_config_check_sig(const void *fit, int noffset,
380 				int required_keynode, int conf_noffset,
381 				char **err_msgp)
382 {
383 	char * const exc_prop[] = {"data"};
384 	const char *prop, *end, *name;
385 	struct image_sign_info info;
386 	const uint32_t *strings;
387 	const char *config_name;
388 	uint8_t *fit_value;
389 	int fit_value_len;
390 	bool found_config;
391 	int max_regions;
392 	int i, prop_len;
393 	char path[200];
394 	int count;
395 
396 	config_name = fit_get_name(fit, conf_noffset, NULL);
397 	debug("%s: fdt=%p, conf='%s', sig='%s'\n", __func__, gd_fdt_blob(),
398 	      fit_get_name(fit, noffset, NULL),
399 	      fit_get_name(gd_fdt_blob(), required_keynode, NULL));
400 	*err_msgp = NULL;
401 	if (fit_image_setup_verify(&info, fit, noffset, required_keynode,
402 				   err_msgp))
403 		return -1;
404 
405 	if (fit_image_hash_get_value(fit, noffset, &fit_value,
406 				     &fit_value_len)) {
407 		*err_msgp = "Can't get hash value property";
408 		return -1;
409 	}
410 
411 	/* Count the number of strings in the property */
412 	prop = fdt_getprop(fit, noffset, "hashed-nodes", &prop_len);
413 	end = prop ? prop + prop_len : prop;
414 	for (name = prop, count = 0; name < end; name++)
415 		if (!*name)
416 			count++;
417 	if (!count) {
418 		*err_msgp = "Can't get hashed-nodes property";
419 		return -1;
420 	}
421 
422 	if (prop && prop_len > 0 && prop[prop_len - 1] != '\0') {
423 		*err_msgp = "hashed-nodes property must be null-terminated";
424 		return -1;
425 	}
426 
427 	/* Add a sanity check here since we are using the stack */
428 	if (count > IMAGE_MAX_HASHED_NODES) {
429 		*err_msgp = "Number of hashed nodes exceeds maximum";
430 		return -1;
431 	}
432 
433 	/* Create a list of node names from those strings */
434 	char *node_inc[count];
435 
436 	debug("Hash nodes (%d):\n", count);
437 	found_config = false;
438 	for (name = prop, i = 0; name < end; name += strlen(name) + 1, i++) {
439 		debug("   '%s'\n", name);
440 		node_inc[i] = (char *)name;
441 		if (!strncmp(FIT_CONFS_PATH, name, strlen(FIT_CONFS_PATH)) &&
442 		    name[sizeof(FIT_CONFS_PATH) - 1] == '/' &&
443 		    !strcmp(name + sizeof(FIT_CONFS_PATH), config_name)) {
444 			debug("      (found config node %s)", config_name);
445 			found_config = true;
446 		}
447 	}
448 	if (!found_config) {
449 		*err_msgp = "Selected config not in hashed nodes";
450 		return -1;
451 	}
452 
453 	/*
454 	 * Each node can generate one region for each sub-node. Allow for
455 	 * 7 sub-nodes (hash-1, signature-1, etc.) and some extra.
456 	 */
457 	max_regions = 20 + count * 7;
458 	struct fdt_region fdt_regions[max_regions];
459 
460 	/* Get a list of regions to hash */
461 	count = fdt_find_regions(fit, node_inc, count,
462 			exc_prop, ARRAY_SIZE(exc_prop),
463 			fdt_regions, max_regions - 1,
464 			path, sizeof(path), 0);
465 	if (count < 0) {
466 		*err_msgp = "Failed to hash configuration";
467 		return -1;
468 	}
469 	if (count == 0) {
470 		*err_msgp = "No data to hash";
471 		return -1;
472 	}
473 	if (count >= max_regions - 1) {
474 		*err_msgp = "Too many hash regions";
475 		return -1;
476 	}
477 
478 	/* Add the strings */
479 	strings = fdt_getprop(fit, noffset, "hashed-strings", NULL);
480 	if (strings) {
481 		/*
482 		 * The strings region offset must be a static 0x0.
483 		 * This is set in tool/image-host.c
484 		 */
485 		fdt_regions[count].offset = fdt_off_dt_strings(fit);
486 		fdt_regions[count].size = fdt32_to_cpu(strings[1]);
487 		count++;
488 	}
489 
490 	/* Allocate the region list on the stack */
491 	struct image_region region[count];
492 
493 	fit_region_make_list(fit, fdt_regions, count, region);
494 	if (info.crypto->verify(&info, region, count, fit_value,
495 				fit_value_len)) {
496 		*err_msgp = "Verification failed";
497 		return -1;
498 	}
499 
500 	return 0;
501 }
502 
503 static int fit_config_verify_sig(const void *fit, int conf_noffset,
504 		const void *sig_blob, int sig_offset)
505 {
506 	int noffset;
507 	char *err_msg = "";
508 	int verified = 0;
509 	int ret;
510 
511 	/* Process all hash subnodes of the component conf node */
512 	fdt_for_each_subnode(noffset, fit, conf_noffset) {
513 		const char *name = fit_get_name(fit, noffset, NULL);
514 
515 		if (!strncmp(name, FIT_SIG_NODENAME,
516 			     strlen(FIT_SIG_NODENAME))) {
517 			ret = fit_config_check_sig(fit, noffset, sig_offset,
518 						   conf_noffset, &err_msg);
519 			if (ret) {
520 				puts("- ");
521 			} else {
522 				puts("+ ");
523 				verified = 1;
524 				break;
525 			}
526 		}
527 	}
528 
529 	if (noffset == -FDT_ERR_TRUNCATED || noffset == -FDT_ERR_BADSTRUCTURE) {
530 		err_msg = "Corrupted or truncated tree";
531 		goto error;
532 	}
533 
534 	if (verified)
535 		return 0;
536 
537 error:
538 	printf(" error!\n%s for '%s' hash node in '%s' config node\n",
539 	       err_msg, fit_get_name(fit, noffset, NULL),
540 	       fit_get_name(fit, conf_noffset, NULL));
541 	return -EPERM;
542 }
543 
544 int fit_config_verify_required_sigs(const void *fit, int conf_noffset,
545 		const void *sig_blob)
546 {
547 	int noffset;
548 	int sig_node;
549 
550 	/* Work out what we need to verify */
551 	sig_node = fdt_subnode_offset(sig_blob, 0, FIT_SIG_NODENAME);
552 	if (sig_node < 0) {
553 		debug("%s: No signature node found: %s\n", __func__,
554 		      fdt_strerror(sig_node));
555 		return 0;
556 	}
557 
558 	fdt_for_each_subnode(noffset, sig_blob, sig_node) {
559 		const char *required;
560 		int ret;
561 
562 		required = fdt_getprop(sig_blob, noffset, "required", NULL);
563 		if (!required || strcmp(required, "conf"))
564 			continue;
565 		ret = fit_config_verify_sig(fit, conf_noffset, sig_blob,
566 					    noffset);
567 		if (ret) {
568 			printf("Failed to verify required signature '%s'\n",
569 			       fit_get_name(sig_blob, noffset, NULL));
570 			return ret;
571 		}
572 	}
573 
574 	return 0;
575 }
576 
577 int fit_config_verify(const void *fit, int conf_noffset)
578 {
579 	return fit_config_verify_required_sigs(fit, conf_noffset,
580 					       gd_fdt_blob());
581 }
582