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