xref: /openbmc/u-boot/common/image-sig.c (revision ed09a554) 
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 		hash_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 		hash_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 		hash_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 	fdt_for_each_subnode(fit, noffset, image_noffset) {
216 		const char *name = fit_get_name(fit, noffset, NULL);
217 
218 		if (!strncmp(name, FIT_SIG_NODENAME,
219 			     strlen(FIT_SIG_NODENAME))) {
220 			ret = fit_image_check_sig(fit, noffset, data,
221 							size, -1, &err_msg);
222 			if (ret) {
223 				puts("- ");
224 			} else {
225 				puts("+ ");
226 				verified = 1;
227 				break;
228 			}
229 		}
230 	}
231 
232 	if (noffset == -FDT_ERR_TRUNCATED || noffset == -FDT_ERR_BADSTRUCTURE) {
233 		err_msg = "Corrupted or truncated tree";
234 		goto error;
235 	}
236 
237 	return verified ? 0 : -EPERM;
238 
239 error:
240 	printf(" error!\n%s for '%s' hash node in '%s' image node\n",
241 	       err_msg, fit_get_name(fit, noffset, NULL),
242 	       fit_get_name(fit, image_noffset, NULL));
243 	return -1;
244 }
245 
246 int fit_image_verify_required_sigs(const void *fit, int image_noffset,
247 		const char *data, size_t size, const void *sig_blob,
248 		int *no_sigsp)
249 {
250 	int verify_count = 0;
251 	int noffset;
252 	int sig_node;
253 
254 	/* Work out what we need to verify */
255 	*no_sigsp = 1;
256 	sig_node = fdt_subnode_offset(sig_blob, 0, FIT_SIG_NODENAME);
257 	if (sig_node < 0) {
258 		debug("%s: No signature node found: %s\n", __func__,
259 		      fdt_strerror(sig_node));
260 		return 0;
261 	}
262 
263 	fdt_for_each_subnode(sig_blob, noffset, sig_node) {
264 		const char *required;
265 		int ret;
266 
267 		required = fdt_getprop(sig_blob, noffset, "required", NULL);
268 		if (!required || strcmp(required, "image"))
269 			continue;
270 		ret = fit_image_verify_sig(fit, image_noffset, data, size,
271 					sig_blob, noffset);
272 		if (ret) {
273 			printf("Failed to verify required signature '%s'\n",
274 			       fit_get_name(sig_blob, noffset, NULL));
275 			return ret;
276 		}
277 		verify_count++;
278 	}
279 
280 	if (verify_count)
281 		*no_sigsp = 0;
282 
283 	return 0;
284 }
285 
286 int fit_config_check_sig(const void *fit, int noffset, int required_keynode,
287 			 char **err_msgp)
288 {
289 	char * const exc_prop[] = {"data"};
290 	const char *prop, *end, *name;
291 	struct image_sign_info info;
292 	const uint32_t *strings;
293 	uint8_t *fit_value;
294 	int fit_value_len;
295 	int max_regions;
296 	int i, prop_len;
297 	char path[200];
298 	int count;
299 
300 	debug("%s: fdt=%p, conf='%s', sig='%s'\n", __func__, gd_fdt_blob(),
301 	      fit_get_name(fit, noffset, NULL),
302 	      fit_get_name(gd_fdt_blob(), required_keynode, NULL));
303 	*err_msgp = NULL;
304 	if (fit_image_setup_verify(&info, fit, noffset, required_keynode,
305 				   err_msgp))
306 		return -1;
307 
308 	if (fit_image_hash_get_value(fit, noffset, &fit_value,
309 				     &fit_value_len)) {
310 		*err_msgp = "Can't get hash value property";
311 		return -1;
312 	}
313 
314 	/* Count the number of strings in the property */
315 	prop = fdt_getprop(fit, noffset, "hashed-nodes", &prop_len);
316 	end = prop ? prop + prop_len : prop;
317 	for (name = prop, count = 0; name < end; name++)
318 		if (!*name)
319 			count++;
320 	if (!count) {
321 		*err_msgp = "Can't get hashed-nodes property";
322 		return -1;
323 	}
324 
325 	/* Add a sanity check here since we are using the stack */
326 	if (count > IMAGE_MAX_HASHED_NODES) {
327 		*err_msgp = "Number of hashed nodes exceeds maximum";
328 		return -1;
329 	}
330 
331 	/* Create a list of node names from those strings */
332 	char *node_inc[count];
333 
334 	debug("Hash nodes (%d):\n", count);
335 	for (name = prop, i = 0; name < end; name += strlen(name) + 1, i++) {
336 		debug("   '%s'\n", name);
337 		node_inc[i] = (char *)name;
338 	}
339 
340 	/*
341 	 * Each node can generate one region for each sub-node. Allow for
342 	 * 7 sub-nodes (hash@1, signature@1, etc.) and some extra.
343 	 */
344 	max_regions = 20 + count * 7;
345 	struct fdt_region fdt_regions[max_regions];
346 
347 	/* Get a list of regions to hash */
348 	count = fdt_find_regions(fit, node_inc, count,
349 			exc_prop, ARRAY_SIZE(exc_prop),
350 			fdt_regions, max_regions - 1,
351 			path, sizeof(path), 0);
352 	if (count < 0) {
353 		*err_msgp = "Failed to hash configuration";
354 		return -1;
355 	}
356 	if (count == 0) {
357 		*err_msgp = "No data to hash";
358 		return -1;
359 	}
360 	if (count >= max_regions - 1) {
361 		*err_msgp = "Too many hash regions";
362 		return -1;
363 	}
364 
365 	/* Add the strings */
366 	strings = fdt_getprop(fit, noffset, "hashed-strings", NULL);
367 	if (strings) {
368 		fdt_regions[count].offset = fdt_off_dt_strings(fit) +
369 				fdt32_to_cpu(strings[0]);
370 		fdt_regions[count].size = fdt32_to_cpu(strings[1]);
371 		count++;
372 	}
373 
374 	/* Allocate the region list on the stack */
375 	struct image_region region[count];
376 
377 	fit_region_make_list(fit, fdt_regions, count, region);
378 	if (info.algo->verify(&info, region, count, fit_value,
379 			      fit_value_len)) {
380 		*err_msgp = "Verification failed";
381 		return -1;
382 	}
383 
384 	return 0;
385 }
386 
387 static int fit_config_verify_sig(const void *fit, int conf_noffset,
388 		const void *sig_blob, int sig_offset)
389 {
390 	int noffset;
391 	char *err_msg = "";
392 	int verified = 0;
393 	int ret;
394 
395 	/* Process all hash subnodes of the component conf node */
396 	fdt_for_each_subnode(fit, noffset, conf_noffset) {
397 		const char *name = fit_get_name(fit, noffset, NULL);
398 
399 		if (!strncmp(name, FIT_SIG_NODENAME,
400 			     strlen(FIT_SIG_NODENAME))) {
401 			ret = fit_config_check_sig(fit, noffset, sig_offset,
402 						   &err_msg);
403 			if (ret) {
404 				puts("- ");
405 			} else {
406 				puts("+ ");
407 				verified = 1;
408 				break;
409 			}
410 		}
411 	}
412 
413 	if (noffset == -FDT_ERR_TRUNCATED || noffset == -FDT_ERR_BADSTRUCTURE) {
414 		err_msg = "Corrupted or truncated tree";
415 		goto error;
416 	}
417 
418 	return verified ? 0 : -EPERM;
419 
420 error:
421 	printf(" error!\n%s for '%s' hash node in '%s' config node\n",
422 	       err_msg, fit_get_name(fit, noffset, NULL),
423 	       fit_get_name(fit, conf_noffset, NULL));
424 	return -1;
425 }
426 
427 int fit_config_verify_required_sigs(const void *fit, int conf_noffset,
428 		const void *sig_blob)
429 {
430 	int noffset;
431 	int sig_node;
432 
433 	/* Work out what we need to verify */
434 	sig_node = fdt_subnode_offset(sig_blob, 0, FIT_SIG_NODENAME);
435 	if (sig_node < 0) {
436 		debug("%s: No signature node found: %s\n", __func__,
437 		      fdt_strerror(sig_node));
438 		return 0;
439 	}
440 
441 	fdt_for_each_subnode(sig_blob, noffset, sig_node) {
442 		const char *required;
443 		int ret;
444 
445 		required = fdt_getprop(sig_blob, noffset, "required", NULL);
446 		if (!required || strcmp(required, "conf"))
447 			continue;
448 		ret = fit_config_verify_sig(fit, conf_noffset, sig_blob,
449 					    noffset);
450 		if (ret) {
451 			printf("Failed to verify required signature '%s'\n",
452 			       fit_get_name(sig_blob, noffset, NULL));
453 			return ret;
454 		}
455 	}
456 
457 	return 0;
458 }
459 
460 int fit_config_verify(const void *fit, int conf_noffset)
461 {
462 	return fit_config_verify_required_sigs(fit, conf_noffset,
463 					       gd_fdt_blob());
464 }
465