xref: /openbmc/u-boot/common/image-sig.c (revision 93322749) 
1 /*
2  * Copyright (c) 2013, Google Inc.
3  *
4  * SPDX-License-Identifier:	GPL-2.0+
5  */
6 
7 #ifdef USE_HOSTCC
8 #include "mkimage.h"
9 #include <time.h>
10 #else
11 #include <common.h>
12 #include <malloc.h>
13 DECLARE_GLOBAL_DATA_PTR;
14 #endif /* !USE_HOSTCC*/
15 #include <image.h>
16 #include <u-boot/rsa.h>
17 #include <u-boot/rsa-checksum.h>
18 
19 #define IMAGE_MAX_HASHED_NODES		100
20 
21 #ifdef USE_HOSTCC
22 void *host_blob;
23 void image_set_host_blob(void *blob)
24 {
25 	host_blob = blob;
26 }
27 void *image_get_host_blob(void)
28 {
29 	return host_blob;
30 }
31 #endif
32 
33 struct checksum_algo checksum_algos[] = {
34 	{
35 		"sha1",
36 		SHA1_SUM_LEN,
37 		RSA2048_BYTES,
38 #if IMAGE_ENABLE_SIGN
39 		EVP_sha1,
40 #endif
41 		sha1_calculate,
42 		padding_sha1_rsa2048,
43 	},
44 	{
45 		"sha256",
46 		SHA256_SUM_LEN,
47 		RSA2048_BYTES,
48 #if IMAGE_ENABLE_SIGN
49 		EVP_sha256,
50 #endif
51 		sha256_calculate,
52 		padding_sha256_rsa2048,
53 	},
54 	{
55 		"sha256",
56 		SHA256_SUM_LEN,
57 		RSA4096_BYTES,
58 #if IMAGE_ENABLE_SIGN
59 		EVP_sha256,
60 #endif
61 		sha256_calculate,
62 		padding_sha256_rsa4096,
63 	}
64 
65 };
66 
67 struct image_sig_algo image_sig_algos[] = {
68 	{
69 		"sha1,rsa2048",
70 		rsa_sign,
71 		rsa_add_verify_data,
72 		rsa_verify,
73 		&checksum_algos[0],
74 	},
75 	{
76 		"sha256,rsa2048",
77 		rsa_sign,
78 		rsa_add_verify_data,
79 		rsa_verify,
80 		&checksum_algos[1],
81 	},
82 	{
83 		"sha256,rsa4096",
84 		rsa_sign,
85 		rsa_add_verify_data,
86 		rsa_verify,
87 		&checksum_algos[2],
88 	}
89 
90 };
91 
92 struct image_sig_algo *image_get_sig_algo(const char *name)
93 {
94 	int i;
95 
96 	for (i = 0; i < ARRAY_SIZE(image_sig_algos); i++) {
97 		if (!strcmp(image_sig_algos[i].name, name))
98 			return &image_sig_algos[i];
99 	}
100 
101 	return NULL;
102 }
103 
104 /**
105  * fit_region_make_list() - Make a list of image regions
106  *
107  * Given a list of fdt_regions, create a list of image_regions. This is a
108  * simple conversion routine since the FDT and image code use different
109  * structures.
110  *
111  * @fit: FIT image
112  * @fdt_regions: Pointer to FDT regions
113  * @count: Number of FDT regions
114  * @region: Pointer to image regions, which must hold @count records. If
115  * region is NULL, then (except for an SPL build) the array will be
116  * allocated.
117  * @return: Pointer to image regions
118  */
119 struct image_region *fit_region_make_list(const void *fit,
120 		struct fdt_region *fdt_regions, int count,
121 		struct image_region *region)
122 {
123 	int i;
124 
125 	debug("Hash regions:\n");
126 	debug("%10s %10s\n", "Offset", "Size");
127 
128 	/*
129 	 * Use malloc() except in SPL (to save code size). In SPL the caller
130 	 * must allocate the array.
131 	 */
132 #ifndef CONFIG_SPL_BUILD
133 	if (!region)
134 		region = calloc(sizeof(*region), count);
135 #endif
136 	if (!region)
137 		return NULL;
138 	for (i = 0; i < count; i++) {
139 		debug("%10x %10x\n", fdt_regions[i].offset,
140 		      fdt_regions[i].size);
141 		region[i].data = fit + fdt_regions[i].offset;
142 		region[i].size = fdt_regions[i].size;
143 	}
144 
145 	return region;
146 }
147 
148 static int fit_image_setup_verify(struct image_sign_info *info,
149 		const void *fit, int noffset, int required_keynode,
150 		char **err_msgp)
151 {
152 	char *algo_name;
153 
154 	if (fit_image_hash_get_algo(fit, noffset, &algo_name)) {
155 		*err_msgp = "Can't get hash algo property";
156 		return -1;
157 	}
158 	memset(info, '\0', sizeof(*info));
159 	info->keyname = fdt_getprop(fit, noffset, "key-name-hint", NULL);
160 	info->fit = (void *)fit;
161 	info->node_offset = noffset;
162 	info->algo = image_get_sig_algo(algo_name);
163 	info->fdt_blob = gd_fdt_blob();
164 	info->required_keynode = required_keynode;
165 	printf("%s:%s", algo_name, info->keyname);
166 
167 	if (!info->algo) {
168 		*err_msgp = "Unknown signature algorithm";
169 		return -1;
170 	}
171 
172 	return 0;
173 }
174 
175 int fit_image_check_sig(const void *fit, int noffset, const void *data,
176 		size_t size, int required_keynode, char **err_msgp)
177 {
178 	struct image_sign_info info;
179 	struct image_region region;
180 	uint8_t *fit_value;
181 	int fit_value_len;
182 
183 	*err_msgp = NULL;
184 	if (fit_image_setup_verify(&info, fit, noffset, required_keynode,
185 				   err_msgp))
186 		return -1;
187 
188 	if (fit_image_hash_get_value(fit, noffset, &fit_value,
189 				     &fit_value_len)) {
190 		*err_msgp = "Can't get hash value property";
191 		return -1;
192 	}
193 
194 	region.data = data;
195 	region.size = size;
196 
197 	if (info.algo->verify(&info, &region, 1, fit_value, fit_value_len)) {
198 		*err_msgp = "Verification failed";
199 		return -1;
200 	}
201 
202 	return 0;
203 }
204 
205 static int fit_image_verify_sig(const void *fit, int image_noffset,
206 		const char *data, size_t size, const void *sig_blob,
207 		int sig_offset)
208 {
209 	int noffset;
210 	char *err_msg = "";
211 	int verified = 0;
212 	int ret;
213 
214 	/* Process all hash subnodes of the component image node */
215 	for (noffset = fdt_first_subnode(fit, image_noffset);
216 	     noffset >= 0;
217 	     noffset = fdt_next_subnode(fit, noffset)) {
218 		const char *name = fit_get_name(fit, noffset, NULL);
219 
220 		if (!strncmp(name, FIT_SIG_NODENAME,
221 			     strlen(FIT_SIG_NODENAME))) {
222 			ret = fit_image_check_sig(fit, noffset, data,
223 							size, -1, &err_msg);
224 			if (ret) {
225 				puts("- ");
226 			} else {
227 				puts("+ ");
228 				verified = 1;
229 				break;
230 			}
231 		}
232 	}
233 
234 	if (noffset == -FDT_ERR_TRUNCATED || noffset == -FDT_ERR_BADSTRUCTURE) {
235 		err_msg = "Corrupted or truncated tree";
236 		goto error;
237 	}
238 
239 	return verified ? 0 : -EPERM;
240 
241 error:
242 	printf(" error!\n%s for '%s' hash node in '%s' image node\n",
243 	       err_msg, fit_get_name(fit, noffset, NULL),
244 	       fit_get_name(fit, image_noffset, NULL));
245 	return -1;
246 }
247 
248 int fit_image_verify_required_sigs(const void *fit, int image_noffset,
249 		const char *data, size_t size, const void *sig_blob,
250 		int *no_sigsp)
251 {
252 	int verify_count = 0;
253 	int noffset;
254 	int sig_node;
255 
256 	/* Work out what we need to verify */
257 	*no_sigsp = 1;
258 	sig_node = fdt_subnode_offset(sig_blob, 0, FIT_SIG_NODENAME);
259 	if (sig_node < 0) {
260 		debug("%s: No signature node found: %s\n", __func__,
261 		      fdt_strerror(sig_node));
262 		return 0;
263 	}
264 
265 	for (noffset = fdt_first_subnode(sig_blob, sig_node);
266 	     noffset >= 0;
267 	     noffset = fdt_next_subnode(sig_blob, noffset)) {
268 		const char *required;
269 		int ret;
270 
271 		required = fdt_getprop(sig_blob, noffset, "required", NULL);
272 		if (!required || strcmp(required, "image"))
273 			continue;
274 		ret = fit_image_verify_sig(fit, image_noffset, data, size,
275 					sig_blob, noffset);
276 		if (ret) {
277 			printf("Failed to verify required signature '%s'\n",
278 			       fit_get_name(sig_blob, noffset, NULL));
279 			return ret;
280 		}
281 		verify_count++;
282 	}
283 
284 	if (verify_count)
285 		*no_sigsp = 0;
286 
287 	return 0;
288 }
289 
290 int fit_config_check_sig(const void *fit, int noffset, int required_keynode,
291 			 char **err_msgp)
292 {
293 	char * const exc_prop[] = {"data"};
294 	const char *prop, *end, *name;
295 	struct image_sign_info info;
296 	const uint32_t *strings;
297 	uint8_t *fit_value;
298 	int fit_value_len;
299 	int max_regions;
300 	int i, prop_len;
301 	char path[200];
302 	int count;
303 
304 	debug("%s: fdt=%p, conf='%s', sig='%s'\n", __func__, gd_fdt_blob(),
305 	      fit_get_name(fit, noffset, NULL),
306 	      fit_get_name(gd_fdt_blob(), required_keynode, NULL));
307 	*err_msgp = NULL;
308 	if (fit_image_setup_verify(&info, fit, noffset, required_keynode,
309 				   err_msgp))
310 		return -1;
311 
312 	if (fit_image_hash_get_value(fit, noffset, &fit_value,
313 				     &fit_value_len)) {
314 		*err_msgp = "Can't get hash value property";
315 		return -1;
316 	}
317 
318 	/* Count the number of strings in the property */
319 	prop = fdt_getprop(fit, noffset, "hashed-nodes", &prop_len);
320 	end = prop ? prop + prop_len : prop;
321 	for (name = prop, count = 0; name < end; name++)
322 		if (!*name)
323 			count++;
324 	if (!count) {
325 		*err_msgp = "Can't get hashed-nodes property";
326 		return -1;
327 	}
328 
329 	/* Add a sanity check here since we are using the stack */
330 	if (count > IMAGE_MAX_HASHED_NODES) {
331 		*err_msgp = "Number of hashed nodes exceeds maximum";
332 		return -1;
333 	}
334 
335 	/* Create a list of node names from those strings */
336 	char *node_inc[count];
337 
338 	debug("Hash nodes (%d):\n", count);
339 	for (name = prop, i = 0; name < end; name += strlen(name) + 1, i++) {
340 		debug("   '%s'\n", name);
341 		node_inc[i] = (char *)name;
342 	}
343 
344 	/*
345 	 * Each node can generate one region for each sub-node. Allow for
346 	 * 7 sub-nodes (hash@1, signature@1, etc.) and some extra.
347 	 */
348 	max_regions = 20 + count * 7;
349 	struct fdt_region fdt_regions[max_regions];
350 
351 	/* Get a list of regions to hash */
352 	count = fdt_find_regions(fit, node_inc, count,
353 			exc_prop, ARRAY_SIZE(exc_prop),
354 			fdt_regions, max_regions - 1,
355 			path, sizeof(path), 0);
356 	if (count < 0) {
357 		*err_msgp = "Failed to hash configuration";
358 		return -1;
359 	}
360 	if (count == 0) {
361 		*err_msgp = "No data to hash";
362 		return -1;
363 	}
364 	if (count >= max_regions - 1) {
365 		*err_msgp = "Too many hash regions";
366 		return -1;
367 	}
368 
369 	/* Add the strings */
370 	strings = fdt_getprop(fit, noffset, "hashed-strings", NULL);
371 	if (strings) {
372 		fdt_regions[count].offset = fdt_off_dt_strings(fit) +
373 				fdt32_to_cpu(strings[0]);
374 		fdt_regions[count].size = fdt32_to_cpu(strings[1]);
375 		count++;
376 	}
377 
378 	/* Allocate the region list on the stack */
379 	struct image_region region[count];
380 
381 	fit_region_make_list(fit, fdt_regions, count, region);
382 	if (info.algo->verify(&info, region, count, fit_value,
383 			      fit_value_len)) {
384 		*err_msgp = "Verification failed";
385 		return -1;
386 	}
387 
388 	return 0;
389 }
390 
391 static int fit_config_verify_sig(const void *fit, int conf_noffset,
392 		const void *sig_blob, int sig_offset)
393 {
394 	int noffset;
395 	char *err_msg = "";
396 	int verified = 0;
397 	int ret;
398 
399 	/* Process all hash subnodes of the component conf node */
400 	for (noffset = fdt_first_subnode(fit, conf_noffset);
401 	     noffset >= 0;
402 	     noffset = fdt_next_subnode(fit, noffset)) {
403 		const char *name = fit_get_name(fit, noffset, NULL);
404 
405 		if (!strncmp(name, FIT_SIG_NODENAME,
406 			     strlen(FIT_SIG_NODENAME))) {
407 			ret = fit_config_check_sig(fit, noffset, sig_offset,
408 						   &err_msg);
409 			if (ret) {
410 				puts("- ");
411 			} else {
412 				puts("+ ");
413 				verified = 1;
414 				break;
415 			}
416 		}
417 	}
418 
419 	if (noffset == -FDT_ERR_TRUNCATED || noffset == -FDT_ERR_BADSTRUCTURE) {
420 		err_msg = "Corrupted or truncated tree";
421 		goto error;
422 	}
423 
424 	return verified ? 0 : -EPERM;
425 
426 error:
427 	printf(" error!\n%s for '%s' hash node in '%s' config node\n",
428 	       err_msg, fit_get_name(fit, noffset, NULL),
429 	       fit_get_name(fit, conf_noffset, NULL));
430 	return -1;
431 }
432 
433 int fit_config_verify_required_sigs(const void *fit, int conf_noffset,
434 		const void *sig_blob)
435 {
436 	int noffset;
437 	int sig_node;
438 
439 	/* Work out what we need to verify */
440 	sig_node = fdt_subnode_offset(sig_blob, 0, FIT_SIG_NODENAME);
441 	if (sig_node < 0) {
442 		debug("%s: No signature node found: %s\n", __func__,
443 		      fdt_strerror(sig_node));
444 		return 0;
445 	}
446 
447 	for (noffset = fdt_first_subnode(sig_blob, sig_node);
448 	     noffset >= 0;
449 	     noffset = fdt_next_subnode(sig_blob, noffset)) {
450 		const char *required;
451 		int ret;
452 
453 		required = fdt_getprop(sig_blob, noffset, "required", NULL);
454 		if (!required || strcmp(required, "conf"))
455 			continue;
456 		ret = fit_config_verify_sig(fit, conf_noffset, sig_blob,
457 					    noffset);
458 		if (ret) {
459 			printf("Failed to verify required signature '%s'\n",
460 			       fit_get_name(sig_blob, noffset, NULL));
461 			return ret;
462 		}
463 	}
464 
465 	return 0;
466 }
467 
468 int fit_config_verify(const void *fit, int conf_noffset)
469 {
470 	return fit_config_verify_required_sigs(fit, conf_noffset,
471 					       gd_fdt_blob());
472 }
473