xref: /openbmc/u-boot/common/image-sig.c (revision 63e22517)
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 (fit_image_hash_get_algo(fit, noffset, &algo_name)) {
160 		*err_msgp = "Can't get hash algo property";
161 		return -1;
162 	}
163 	memset(info, '\0', sizeof(*info));
164 	info->keyname = fdt_getprop(fit, noffset, "key-name-hint", NULL);
165 	info->fit = (void *)fit;
166 	info->node_offset = noffset;
167 	info->name = algo_name;
168 	info->checksum = image_get_checksum_algo(algo_name);
169 	info->crypto = image_get_crypto_algo(algo_name);
170 	info->fdt_blob = gd_fdt_blob();
171 	info->required_keynode = required_keynode;
172 	printf("%s:%s", algo_name, info->keyname);
173 
174 	if (!info->checksum || !info->crypto) {
175 		*err_msgp = "Unknown signature algorithm";
176 		return -1;
177 	}
178 
179 	return 0;
180 }
181 
182 int fit_image_check_sig(const void *fit, int noffset, const void *data,
183 		size_t size, int required_keynode, char **err_msgp)
184 {
185 	struct image_sign_info info;
186 	struct image_region region;
187 	uint8_t *fit_value;
188 	int fit_value_len;
189 
190 	*err_msgp = NULL;
191 	if (fit_image_setup_verify(&info, fit, noffset, required_keynode,
192 				   err_msgp))
193 		return -1;
194 
195 	if (fit_image_hash_get_value(fit, noffset, &fit_value,
196 				     &fit_value_len)) {
197 		*err_msgp = "Can't get hash value property";
198 		return -1;
199 	}
200 
201 	region.data = data;
202 	region.size = size;
203 
204 	if (info.crypto->verify(&info, &region, 1, fit_value, fit_value_len)) {
205 		*err_msgp = "Verification failed";
206 		return -1;
207 	}
208 
209 	return 0;
210 }
211 
212 static int fit_image_verify_sig(const void *fit, int image_noffset,
213 		const char *data, size_t size, const void *sig_blob,
214 		int sig_offset)
215 {
216 	int noffset;
217 	char *err_msg = "";
218 	int verified = 0;
219 	int ret;
220 
221 	/* Process all hash subnodes of the component image node */
222 	fdt_for_each_subnode(noffset, fit, image_noffset) {
223 		const char *name = fit_get_name(fit, noffset, NULL);
224 
225 		if (!strncmp(name, FIT_SIG_NODENAME,
226 			     strlen(FIT_SIG_NODENAME))) {
227 			ret = fit_image_check_sig(fit, noffset, data,
228 							size, -1, &err_msg);
229 			if (ret) {
230 				puts("- ");
231 			} else {
232 				puts("+ ");
233 				verified = 1;
234 				break;
235 			}
236 		}
237 	}
238 
239 	if (noffset == -FDT_ERR_TRUNCATED || noffset == -FDT_ERR_BADSTRUCTURE) {
240 		err_msg = "Corrupted or truncated tree";
241 		goto error;
242 	}
243 
244 	return verified ? 0 : -EPERM;
245 
246 error:
247 	printf(" error!\n%s for '%s' hash node in '%s' image node\n",
248 	       err_msg, fit_get_name(fit, noffset, NULL),
249 	       fit_get_name(fit, image_noffset, NULL));
250 	return -1;
251 }
252 
253 int fit_image_verify_required_sigs(const void *fit, int image_noffset,
254 		const char *data, size_t size, const void *sig_blob,
255 		int *no_sigsp)
256 {
257 	int verify_count = 0;
258 	int noffset;
259 	int sig_node;
260 
261 	/* Work out what we need to verify */
262 	*no_sigsp = 1;
263 	sig_node = fdt_subnode_offset(sig_blob, 0, FIT_SIG_NODENAME);
264 	if (sig_node < 0) {
265 		debug("%s: No signature node found: %s\n", __func__,
266 		      fdt_strerror(sig_node));
267 		return 0;
268 	}
269 
270 	fdt_for_each_subnode(noffset, sig_blob, sig_node) {
271 		const char *required;
272 		int ret;
273 
274 		required = fdt_getprop(sig_blob, noffset, "required", NULL);
275 		if (!required || strcmp(required, "image"))
276 			continue;
277 		ret = fit_image_verify_sig(fit, image_noffset, data, size,
278 					sig_blob, noffset);
279 		if (ret) {
280 			printf("Failed to verify required signature '%s'\n",
281 			       fit_get_name(sig_blob, noffset, NULL));
282 			return ret;
283 		}
284 		verify_count++;
285 	}
286 
287 	if (verify_count)
288 		*no_sigsp = 0;
289 
290 	return 0;
291 }
292 
293 int fit_config_check_sig(const void *fit, int noffset, int required_keynode,
294 			 char **err_msgp)
295 {
296 	char * const exc_prop[] = {"data"};
297 	const char *prop, *end, *name;
298 	struct image_sign_info info;
299 	const uint32_t *strings;
300 	uint8_t *fit_value;
301 	int fit_value_len;
302 	int max_regions;
303 	int i, prop_len;
304 	char path[200];
305 	int count;
306 
307 	debug("%s: fdt=%p, conf='%s', sig='%s'\n", __func__, gd_fdt_blob(),
308 	      fit_get_name(fit, noffset, NULL),
309 	      fit_get_name(gd_fdt_blob(), required_keynode, NULL));
310 	*err_msgp = NULL;
311 	if (fit_image_setup_verify(&info, fit, noffset, required_keynode,
312 				   err_msgp))
313 		return -1;
314 
315 	if (fit_image_hash_get_value(fit, noffset, &fit_value,
316 				     &fit_value_len)) {
317 		*err_msgp = "Can't get hash value property";
318 		return -1;
319 	}
320 
321 	/* Count the number of strings in the property */
322 	prop = fdt_getprop(fit, noffset, "hashed-nodes", &prop_len);
323 	end = prop ? prop + prop_len : prop;
324 	for (name = prop, count = 0; name < end; name++)
325 		if (!*name)
326 			count++;
327 	if (!count) {
328 		*err_msgp = "Can't get hashed-nodes property";
329 		return -1;
330 	}
331 
332 	/* Add a sanity check here since we are using the stack */
333 	if (count > IMAGE_MAX_HASHED_NODES) {
334 		*err_msgp = "Number of hashed nodes exceeds maximum";
335 		return -1;
336 	}
337 
338 	/* Create a list of node names from those strings */
339 	char *node_inc[count];
340 
341 	debug("Hash nodes (%d):\n", count);
342 	for (name = prop, i = 0; name < end; name += strlen(name) + 1, i++) {
343 		debug("   '%s'\n", name);
344 		node_inc[i] = (char *)name;
345 	}
346 
347 	/*
348 	 * Each node can generate one region for each sub-node. Allow for
349 	 * 7 sub-nodes (hash-1, signature-1, etc.) and some extra.
350 	 */
351 	max_regions = 20 + count * 7;
352 	struct fdt_region fdt_regions[max_regions];
353 
354 	/* Get a list of regions to hash */
355 	count = fdt_find_regions(fit, node_inc, count,
356 			exc_prop, ARRAY_SIZE(exc_prop),
357 			fdt_regions, max_regions - 1,
358 			path, sizeof(path), 0);
359 	if (count < 0) {
360 		*err_msgp = "Failed to hash configuration";
361 		return -1;
362 	}
363 	if (count == 0) {
364 		*err_msgp = "No data to hash";
365 		return -1;
366 	}
367 	if (count >= max_regions - 1) {
368 		*err_msgp = "Too many hash regions";
369 		return -1;
370 	}
371 
372 	/* Add the strings */
373 	strings = fdt_getprop(fit, noffset, "hashed-strings", NULL);
374 	if (strings) {
375 		fdt_regions[count].offset = fdt_off_dt_strings(fit) +
376 				fdt32_to_cpu(strings[0]);
377 		fdt_regions[count].size = fdt32_to_cpu(strings[1]);
378 		count++;
379 	}
380 
381 	/* Allocate the region list on the stack */
382 	struct image_region region[count];
383 
384 	fit_region_make_list(fit, fdt_regions, count, region);
385 	if (info.crypto->verify(&info, region, count, fit_value,
386 				fit_value_len)) {
387 		*err_msgp = "Verification failed";
388 		return -1;
389 	}
390 
391 	return 0;
392 }
393 
394 static int fit_config_verify_sig(const void *fit, int conf_noffset,
395 		const void *sig_blob, int sig_offset)
396 {
397 	int noffset;
398 	char *err_msg = "";
399 	int verified = 0;
400 	int ret;
401 
402 	/* Process all hash subnodes of the component conf node */
403 	fdt_for_each_subnode(noffset, fit, conf_noffset) {
404 		const char *name = fit_get_name(fit, noffset, NULL);
405 
406 		if (!strncmp(name, FIT_SIG_NODENAME,
407 			     strlen(FIT_SIG_NODENAME))) {
408 			ret = fit_config_check_sig(fit, noffset, sig_offset,
409 						   &err_msg);
410 			if (ret) {
411 				puts("- ");
412 			} else {
413 				puts("+ ");
414 				verified = 1;
415 				break;
416 			}
417 		}
418 	}
419 
420 	if (noffset == -FDT_ERR_TRUNCATED || noffset == -FDT_ERR_BADSTRUCTURE) {
421 		err_msg = "Corrupted or truncated tree";
422 		goto error;
423 	}
424 
425 	return verified ? 0 : -EPERM;
426 
427 error:
428 	printf(" error!\n%s for '%s' hash node in '%s' config node\n",
429 	       err_msg, fit_get_name(fit, noffset, NULL),
430 	       fit_get_name(fit, conf_noffset, NULL));
431 	return -1;
432 }
433 
434 int fit_config_verify_required_sigs(const void *fit, int conf_noffset,
435 		const void *sig_blob)
436 {
437 	int noffset;
438 	int sig_node;
439 
440 	/* Work out what we need to verify */
441 	sig_node = fdt_subnode_offset(sig_blob, 0, FIT_SIG_NODENAME);
442 	if (sig_node < 0) {
443 		debug("%s: No signature node found: %s\n", __func__,
444 		      fdt_strerror(sig_node));
445 		return 0;
446 	}
447 
448 	fdt_for_each_subnode(noffset, sig_blob, sig_node) {
449 		const char *required;
450 		int ret;
451 
452 		required = fdt_getprop(sig_blob, noffset, "required", NULL);
453 		if (!required || strcmp(required, "conf"))
454 			continue;
455 		ret = fit_config_verify_sig(fit, conf_noffset, sig_blob,
456 					    noffset);
457 		if (ret) {
458 			printf("Failed to verify required signature '%s'\n",
459 			       fit_get_name(sig_blob, noffset, NULL));
460 			return ret;
461 		}
462 	}
463 
464 	return 0;
465 }
466 
467 int fit_config_verify(const void *fit, int conf_noffset)
468 {
469 	return fit_config_verify_required_sigs(fit, conf_noffset,
470 					       gd_fdt_blob());
471 }
472