xref: /openbmc/u-boot/common/image-sig.c (revision cbd2fba1) 
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 
54 };
55 
56 struct crypto_algo crypto_algos[] = {
57 	{
58 		.name = "rsa2048",
59 		.key_len = RSA2048_BYTES,
60 		.sign = rsa_sign,
61 		.add_verify_data = rsa_add_verify_data,
62 		.verify = rsa_verify,
63 	},
64 	{
65 		.name = "rsa4096",
66 		.key_len = RSA4096_BYTES,
67 		.sign = rsa_sign,
68 		.add_verify_data = rsa_add_verify_data,
69 		.verify = rsa_verify,
70 	}
71 
72 };
73 
74 struct checksum_algo *image_get_checksum_algo(const char *full_name)
75 {
76 	int i;
77 	const char *name;
78 
79 	for (i = 0; i < ARRAY_SIZE(checksum_algos); i++) {
80 		name = checksum_algos[i].name;
81 		/* Make sure names match and next char is a comma */
82 		if (!strncmp(name, full_name, strlen(name)) &&
83 		    full_name[strlen(name)] == ',')
84 			return &checksum_algos[i];
85 	}
86 
87 	return NULL;
88 }
89 
90 struct crypto_algo *image_get_crypto_algo(const char *full_name)
91 {
92 	int i;
93 	const char *name;
94 
95 	/* Move name to after the comma */
96 	name = strchr(full_name, ',');
97 	if (!name)
98 		return NULL;
99 	name += 1;
100 
101 	for (i = 0; i < ARRAY_SIZE(crypto_algos); i++) {
102 		if (!strcmp(crypto_algos[i].name, name))
103 			return &crypto_algos[i];
104 	}
105 
106 	return NULL;
107 }
108 
109 /**
110  * fit_region_make_list() - Make a list of image regions
111  *
112  * Given a list of fdt_regions, create a list of image_regions. This is a
113  * simple conversion routine since the FDT and image code use different
114  * structures.
115  *
116  * @fit: FIT image
117  * @fdt_regions: Pointer to FDT regions
118  * @count: Number of FDT regions
119  * @region: Pointer to image regions, which must hold @count records. If
120  * region is NULL, then (except for an SPL build) the array will be
121  * allocated.
122  * @return: Pointer to image regions
123  */
124 struct image_region *fit_region_make_list(const void *fit,
125 		struct fdt_region *fdt_regions, int count,
126 		struct image_region *region)
127 {
128 	int i;
129 
130 	debug("Hash regions:\n");
131 	debug("%10s %10s\n", "Offset", "Size");
132 
133 	/*
134 	 * Use malloc() except in SPL (to save code size). In SPL the caller
135 	 * must allocate the array.
136 	 */
137 #ifndef CONFIG_SPL_BUILD
138 	if (!region)
139 		region = calloc(sizeof(*region), count);
140 #endif
141 	if (!region)
142 		return NULL;
143 	for (i = 0; i < count; i++) {
144 		debug("%10x %10x\n", fdt_regions[i].offset,
145 		      fdt_regions[i].size);
146 		region[i].data = fit + fdt_regions[i].offset;
147 		region[i].size = fdt_regions[i].size;
148 	}
149 
150 	return region;
151 }
152 
153 static int fit_image_setup_verify(struct image_sign_info *info,
154 		const void *fit, int noffset, int required_keynode,
155 		char **err_msgp)
156 {
157 	char *algo_name;
158 
159 	if (fdt_totalsize(fit) > CONFIG_FIT_SIGNATURE_MAX_SIZE) {
160 		*err_msgp = "Total size too large";
161 		return 1;
162 	}
163 
164 	if (fit_image_hash_get_algo(fit, noffset, &algo_name)) {
165 		*err_msgp = "Can't get hash algo property";
166 		return -1;
167 	}
168 	memset(info, '\0', sizeof(*info));
169 	info->keyname = fdt_getprop(fit, noffset, "key-name-hint", NULL);
170 	info->fit = (void *)fit;
171 	info->node_offset = noffset;
172 	info->name = algo_name;
173 	info->checksum = image_get_checksum_algo(algo_name);
174 	info->crypto = image_get_crypto_algo(algo_name);
175 	info->fdt_blob = gd_fdt_blob();
176 	info->required_keynode = required_keynode;
177 	printf("%s:%s", algo_name, info->keyname);
178 
179 	if (!info->checksum || !info->crypto) {
180 		*err_msgp = "Unknown signature algorithm";
181 		return -1;
182 	}
183 
184 	return 0;
185 }
186 
187 int fit_image_check_sig(const void *fit, int noffset, const void *data,
188 		size_t size, int required_keynode, char **err_msgp)
189 {
190 	struct image_sign_info info;
191 	struct image_region region;
192 	uint8_t *fit_value;
193 	int fit_value_len;
194 
195 	*err_msgp = NULL;
196 	if (fit_image_setup_verify(&info, fit, noffset, required_keynode,
197 				   err_msgp))
198 		return -1;
199 
200 	if (fit_image_hash_get_value(fit, noffset, &fit_value,
201 				     &fit_value_len)) {
202 		*err_msgp = "Can't get hash value property";
203 		return -1;
204 	}
205 
206 	region.data = data;
207 	region.size = size;
208 
209 	if (info.crypto->verify(&info, &region, 1, fit_value, fit_value_len)) {
210 		*err_msgp = "Verification failed";
211 		return -1;
212 	}
213 
214 	return 0;
215 }
216 
217 static int fit_image_verify_sig(const void *fit, int image_noffset,
218 		const char *data, size_t size, const void *sig_blob,
219 		int sig_offset)
220 {
221 	int noffset;
222 	char *err_msg = "";
223 	int verified = 0;
224 	int ret;
225 
226 	/* Process all hash subnodes of the component image node */
227 	fdt_for_each_subnode(noffset, fit, image_noffset) {
228 		const char *name = fit_get_name(fit, noffset, NULL);
229 
230 		if (!strncmp(name, FIT_SIG_NODENAME,
231 			     strlen(FIT_SIG_NODENAME))) {
232 			ret = fit_image_check_sig(fit, noffset, data,
233 							size, -1, &err_msg);
234 			if (ret) {
235 				puts("- ");
236 			} else {
237 				puts("+ ");
238 				verified = 1;
239 				break;
240 			}
241 		}
242 	}
243 
244 	if (noffset == -FDT_ERR_TRUNCATED || noffset == -FDT_ERR_BADSTRUCTURE) {
245 		err_msg = "Corrupted or truncated tree";
246 		goto error;
247 	}
248 
249 	return verified ? 0 : -EPERM;
250 
251 error:
252 	printf(" error!\n%s for '%s' hash node in '%s' image node\n",
253 	       err_msg, fit_get_name(fit, noffset, NULL),
254 	       fit_get_name(fit, image_noffset, NULL));
255 	return -1;
256 }
257 
258 int fit_image_verify_required_sigs(const void *fit, int image_noffset,
259 		const char *data, size_t size, const void *sig_blob,
260 		int *no_sigsp)
261 {
262 	int verify_count = 0;
263 	int noffset;
264 	int sig_node;
265 
266 	/* Work out what we need to verify */
267 	*no_sigsp = 1;
268 	sig_node = fdt_subnode_offset(sig_blob, 0, FIT_SIG_NODENAME);
269 	if (sig_node < 0) {
270 		debug("%s: No signature node found: %s\n", __func__,
271 		      fdt_strerror(sig_node));
272 		return 0;
273 	}
274 
275 	fdt_for_each_subnode(noffset, sig_blob, sig_node) {
276 		const char *required;
277 		int ret;
278 
279 		required = fdt_getprop(sig_blob, noffset, "required", NULL);
280 		if (!required || strcmp(required, "image"))
281 			continue;
282 		ret = fit_image_verify_sig(fit, image_noffset, data, size,
283 					sig_blob, noffset);
284 		if (ret) {
285 			printf("Failed to verify required signature '%s'\n",
286 			       fit_get_name(sig_blob, noffset, NULL));
287 			return ret;
288 		}
289 		verify_count++;
290 	}
291 
292 	if (verify_count)
293 		*no_sigsp = 0;
294 
295 	return 0;
296 }
297 
298 int fit_config_check_sig(const void *fit, int noffset, int required_keynode,
299 			 char **err_msgp)
300 {
301 	char * const exc_prop[] = {"data"};
302 	const char *prop, *end, *name;
303 	struct image_sign_info info;
304 	const uint32_t *strings;
305 	uint8_t *fit_value;
306 	int fit_value_len;
307 	int max_regions;
308 	int i, prop_len;
309 	char path[200];
310 	int count;
311 
312 	debug("%s: fdt=%p, conf='%s', sig='%s'\n", __func__, gd_fdt_blob(),
313 	      fit_get_name(fit, noffset, NULL),
314 	      fit_get_name(gd_fdt_blob(), required_keynode, NULL));
315 	*err_msgp = NULL;
316 	if (fit_image_setup_verify(&info, fit, noffset, required_keynode,
317 				   err_msgp))
318 		return -1;
319 
320 	if (fit_image_hash_get_value(fit, noffset, &fit_value,
321 				     &fit_value_len)) {
322 		*err_msgp = "Can't get hash value property";
323 		return -1;
324 	}
325 
326 	/* Count the number of strings in the property */
327 	prop = fdt_getprop(fit, noffset, "hashed-nodes", &prop_len);
328 	end = prop ? prop + prop_len : prop;
329 	for (name = prop, count = 0; name < end; name++)
330 		if (!*name)
331 			count++;
332 	if (!count) {
333 		*err_msgp = "Can't get hashed-nodes property";
334 		return -1;
335 	}
336 
337 	if (prop && prop_len > 0 && prop[prop_len - 1] != '\0') {
338 		*err_msgp = "hashed-nodes property must be null-terminated";
339 		return -1;
340 	}
341 
342 	/* Add a sanity check here since we are using the stack */
343 	if (count > IMAGE_MAX_HASHED_NODES) {
344 		*err_msgp = "Number of hashed nodes exceeds maximum";
345 		return -1;
346 	}
347 
348 	/* Create a list of node names from those strings */
349 	char *node_inc[count];
350 
351 	debug("Hash nodes (%d):\n", count);
352 	for (name = prop, i = 0; name < end; name += strlen(name) + 1, i++) {
353 		debug("   '%s'\n", name);
354 		node_inc[i] = (char *)name;
355 	}
356 
357 	/*
358 	 * Each node can generate one region for each sub-node. Allow for
359 	 * 7 sub-nodes (hash-1, signature-1, etc.) and some extra.
360 	 */
361 	max_regions = 20 + count * 7;
362 	struct fdt_region fdt_regions[max_regions];
363 
364 	/* Get a list of regions to hash */
365 	count = fdt_find_regions(fit, node_inc, count,
366 			exc_prop, ARRAY_SIZE(exc_prop),
367 			fdt_regions, max_regions - 1,
368 			path, sizeof(path), 0);
369 	if (count < 0) {
370 		*err_msgp = "Failed to hash configuration";
371 		return -1;
372 	}
373 	if (count == 0) {
374 		*err_msgp = "No data to hash";
375 		return -1;
376 	}
377 	if (count >= max_regions - 1) {
378 		*err_msgp = "Too many hash regions";
379 		return -1;
380 	}
381 
382 	/* Add the strings */
383 	strings = fdt_getprop(fit, noffset, "hashed-strings", NULL);
384 	if (strings) {
385 		/*
386 		 * The strings region offset must be a static 0x0.
387 		 * This is set in tool/image-host.c
388 		 */
389 		fdt_regions[count].offset = fdt_off_dt_strings(fit);
390 		fdt_regions[count].size = fdt32_to_cpu(strings[1]);
391 		count++;
392 	}
393 
394 	/* Allocate the region list on the stack */
395 	struct image_region region[count];
396 
397 	fit_region_make_list(fit, fdt_regions, count, region);
398 	if (info.crypto->verify(&info, region, count, fit_value,
399 				fit_value_len)) {
400 		*err_msgp = "Verification failed";
401 		return -1;
402 	}
403 
404 	return 0;
405 }
406 
407 static int fit_config_verify_sig(const void *fit, int conf_noffset,
408 		const void *sig_blob, int sig_offset)
409 {
410 	int noffset;
411 	char *err_msg = "";
412 	int verified = 0;
413 	int ret;
414 
415 	/* Process all hash subnodes of the component conf node */
416 	fdt_for_each_subnode(noffset, fit, conf_noffset) {
417 		const char *name = fit_get_name(fit, noffset, NULL);
418 
419 		if (!strncmp(name, FIT_SIG_NODENAME,
420 			     strlen(FIT_SIG_NODENAME))) {
421 			ret = fit_config_check_sig(fit, noffset, sig_offset,
422 						   &err_msg);
423 			if (ret) {
424 				puts("- ");
425 			} else {
426 				puts("+ ");
427 				verified = 1;
428 				break;
429 			}
430 		}
431 	}
432 
433 	if (noffset == -FDT_ERR_TRUNCATED || noffset == -FDT_ERR_BADSTRUCTURE) {
434 		err_msg = "Corrupted or truncated tree";
435 		goto error;
436 	}
437 
438 	return verified ? 0 : -EPERM;
439 
440 error:
441 	printf(" error!\n%s for '%s' hash node in '%s' config node\n",
442 	       err_msg, fit_get_name(fit, noffset, NULL),
443 	       fit_get_name(fit, conf_noffset, NULL));
444 	return -1;
445 }
446 
447 int fit_config_verify_required_sigs(const void *fit, int conf_noffset,
448 		const void *sig_blob)
449 {
450 	int noffset;
451 	int sig_node;
452 
453 	/* Work out what we need to verify */
454 	sig_node = fdt_subnode_offset(sig_blob, 0, FIT_SIG_NODENAME);
455 	if (sig_node < 0) {
456 		debug("%s: No signature node found: %s\n", __func__,
457 		      fdt_strerror(sig_node));
458 		return 0;
459 	}
460 
461 	fdt_for_each_subnode(noffset, sig_blob, sig_node) {
462 		const char *required;
463 		int ret;
464 
465 		required = fdt_getprop(sig_blob, noffset, "required", NULL);
466 		if (!required || strcmp(required, "conf"))
467 			continue;
468 		ret = fit_config_verify_sig(fit, conf_noffset, sig_blob,
469 					    noffset);
470 		if (ret) {
471 			printf("Failed to verify required signature '%s'\n",
472 			       fit_get_name(sig_blob, noffset, NULL));
473 			return ret;
474 		}
475 	}
476 
477 	return 0;
478 }
479 
480 int fit_config_verify(const void *fit, int conf_noffset)
481 {
482 	return fit_config_verify_required_sigs(fit, conf_noffset,
483 					       gd_fdt_blob());
484 }
485