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>
14 DECLARE_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 */
fit_region_make_list(const void * fit,struct fdt_region * fdt_regions,int count,struct image_region * region)38 struct 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
fit_image_setup_verify(struct image_sign_info * info,const void * fit,int noffset,int required_keynode,char ** err_msgp)66 static int fit_image_setup_verify(struct image_sign_info *info,
67 const void *fit, int noffset,
68 int required_keynode, char **err_msgp)
69 {
70 char *algo_name;
71 const char *padding_name;
72
73 if (fdt_totalsize(fit) > CONFIG_VAL(FIT_SIGNATURE_MAX_SIZE)) {
74 *err_msgp = "Total size too large";
75 return 1;
76 }
77 if (fit_image_hash_get_algo(fit, noffset, &algo_name)) {
78 *err_msgp = "Can't get hash algo property";
79 return -1;
80 }
81
82 padding_name = fdt_getprop(fit, noffset, "padding", NULL);
83 if (!padding_name)
84 padding_name = RSA_DEFAULT_PADDING_NAME;
85
86 memset(info, '\0', sizeof(*info));
87 info->keyname = fdt_getprop(fit, noffset, FIT_KEY_HINT, NULL);
88 info->fit = fit;
89 info->node_offset = noffset;
90 info->name = algo_name;
91 info->checksum = image_get_checksum_algo(algo_name);
92 info->crypto = image_get_crypto_algo(algo_name);
93 info->padding = image_get_padding_algo(padding_name);
94 info->fdt_blob = gd_fdt_blob();
95 info->required_keynode = required_keynode;
96 printf("%s:%s", algo_name, info->keyname);
97
98 if (!info->checksum || !info->crypto || !info->padding) {
99 *err_msgp = "Unknown signature algorithm";
100 return -1;
101 }
102
103 return 0;
104 }
105
fit_image_check_sig(const void * fit,int noffset,const void * data,size_t size,int required_keynode,char ** err_msgp)106 int fit_image_check_sig(const void *fit, int noffset, const void *data,
107 size_t size, int required_keynode, char **err_msgp)
108 {
109 struct image_sign_info info;
110 struct image_region region;
111 uint8_t *fit_value;
112 int fit_value_len;
113
114 *err_msgp = NULL;
115 if (fit_image_setup_verify(&info, fit, noffset, required_keynode,
116 err_msgp))
117 return -1;
118
119 if (fit_image_hash_get_value(fit, noffset, &fit_value,
120 &fit_value_len)) {
121 *err_msgp = "Can't get hash value property";
122 return -1;
123 }
124
125 region.data = data;
126 region.size = size;
127
128 if (info.crypto->verify(&info, ®ion, 1, fit_value, fit_value_len)) {
129 *err_msgp = "Verification failed";
130 return -1;
131 }
132
133 return 0;
134 }
135
fit_image_verify_sig(const void * fit,int image_noffset,const char * data,size_t size,const void * sig_blob,int sig_offset)136 static int fit_image_verify_sig(const void *fit, int image_noffset,
137 const char *data, size_t size,
138 const void *sig_blob, int sig_offset)
139 {
140 int noffset;
141 char *err_msg = "";
142 int verified = 0;
143 int ret;
144
145 /* Process all hash subnodes of the component image node */
146 fdt_for_each_subnode(noffset, fit, image_noffset) {
147 const char *name = fit_get_name(fit, noffset, NULL);
148
149 /*
150 * We don't support this since libfdt considers names with the
151 * name root but different @ suffix to be equal
152 */
153 if (strchr(name, '@')) {
154 err_msg = "Node name contains @";
155 goto error;
156 }
157 if (!strncmp(name, FIT_SIG_NODENAME,
158 strlen(FIT_SIG_NODENAME))) {
159 ret = fit_image_check_sig(fit, noffset, data,
160 size, -1, &err_msg);
161 if (ret) {
162 puts("- ");
163 } else {
164 puts("+ ");
165 verified = 1;
166 break;
167 }
168 }
169 }
170
171 if (noffset == -FDT_ERR_TRUNCATED || noffset == -FDT_ERR_BADSTRUCTURE) {
172 err_msg = "Corrupted or truncated tree";
173 goto error;
174 }
175
176 return verified ? 0 : -EPERM;
177
178 error:
179 printf(" error!\n%s for '%s' hash node in '%s' image node\n",
180 err_msg, fit_get_name(fit, noffset, NULL),
181 fit_get_name(fit, image_noffset, NULL));
182 return -1;
183 }
184
fit_image_verify_required_sigs(const void * fit,int image_noffset,const char * data,size_t size,const void * sig_blob,int * no_sigsp)185 int fit_image_verify_required_sigs(const void *fit, int image_noffset,
186 const char *data, size_t size,
187 const void *sig_blob, int *no_sigsp)
188 {
189 int verify_count = 0;
190 int noffset;
191 int sig_node;
192
193 /* Work out what we need to verify */
194 *no_sigsp = 1;
195 sig_node = fdt_subnode_offset(sig_blob, 0, FIT_SIG_NODENAME);
196 if (sig_node < 0) {
197 debug("%s: No signature node found: %s\n", __func__,
198 fdt_strerror(sig_node));
199 return 0;
200 }
201
202 fdt_for_each_subnode(noffset, sig_blob, sig_node) {
203 const char *required;
204 int ret;
205
206 required = fdt_getprop(sig_blob, noffset, FIT_KEY_REQUIRED,
207 NULL);
208 if (!required || strcmp(required, "image"))
209 continue;
210 ret = fit_image_verify_sig(fit, image_noffset, data, size,
211 sig_blob, noffset);
212 if (ret) {
213 printf("Failed to verify required signature '%s'\n",
214 fit_get_name(sig_blob, noffset, NULL));
215 return ret;
216 }
217 verify_count++;
218 }
219
220 if (verify_count)
221 *no_sigsp = 0;
222
223 return 0;
224 }
225
226 /**
227 * fit_config_check_sig() - Check the signature of a config
228 *
229 * @fit: FIT to check
230 * @noffset: Offset of configuration node (e.g. /configurations/conf-1)
231 * @required_keynode: Offset in the control FDT of the required key node,
232 * if any. If this is given, then the configuration wil not
233 * pass verification unless that key is used. If this is
234 * -1 then any signature will do.
235 * @conf_noffset: Offset of the configuration subnode being checked (e.g.
236 * /configurations/conf-1/kernel)
237 * @err_msgp: In the event of an error, this will be pointed to a
238 * help error string to display to the user.
239 * @return 0 if all verified ok, <0 on error
240 */
fit_config_check_sig(const void * fit,int noffset,int required_keynode,int conf_noffset,char ** err_msgp)241 static int fit_config_check_sig(const void *fit, int noffset,
242 int required_keynode, int conf_noffset,
243 char **err_msgp)
244 {
245 static char * const exc_prop[] = {
246 "data",
247 "data-size",
248 "data-position",
249 "data-offset"
250 };
251
252 const char *prop, *end, *name;
253 struct image_sign_info info;
254 const uint32_t *strings;
255 const char *config_name;
256 uint8_t *fit_value;
257 int fit_value_len;
258 bool found_config;
259 int max_regions;
260 int i, prop_len;
261 char path[200];
262 int count;
263
264 config_name = fit_get_name(fit, conf_noffset, NULL);
265 debug("%s: fdt=%p, conf='%s', sig='%s'\n", __func__, gd_fdt_blob(),
266 fit_get_name(fit, noffset, NULL),
267 fit_get_name(gd_fdt_blob(), required_keynode, NULL));
268 *err_msgp = NULL;
269 if (fit_image_setup_verify(&info, fit, noffset, required_keynode,
270 err_msgp))
271 return -1;
272
273 if (fit_image_hash_get_value(fit, noffset, &fit_value,
274 &fit_value_len)) {
275 *err_msgp = "Can't get hash value property";
276 return -1;
277 }
278
279 /* Count the number of strings in the property */
280 prop = fdt_getprop(fit, noffset, "hashed-nodes", &prop_len);
281 end = prop ? prop + prop_len : prop;
282 for (name = prop, count = 0; name < end; name++)
283 if (!*name)
284 count++;
285 if (!count) {
286 *err_msgp = "Can't get hashed-nodes property";
287 return -1;
288 }
289
290 if (prop && prop_len > 0 && prop[prop_len - 1] != '\0') {
291 *err_msgp = "hashed-nodes property must be null-terminated";
292 return -1;
293 }
294
295 /* Add a sanity check here since we are using the stack */
296 if (count > IMAGE_MAX_HASHED_NODES) {
297 *err_msgp = "Number of hashed nodes exceeds maximum";
298 return -1;
299 }
300
301 /* Create a list of node names from those strings */
302 char *node_inc[count];
303
304 debug("Hash nodes (%d):\n", count);
305 found_config = false;
306 for (name = prop, i = 0; name < end; name += strlen(name) + 1, i++) {
307 debug(" '%s'\n", name);
308 node_inc[i] = (char *)name;
309 if (!strncmp(FIT_CONFS_PATH, name, strlen(FIT_CONFS_PATH)) &&
310 name[sizeof(FIT_CONFS_PATH) - 1] == '/' &&
311 !strcmp(name + sizeof(FIT_CONFS_PATH), config_name)) {
312 debug(" (found config node %s)", config_name);
313 found_config = true;
314 }
315 }
316 if (!found_config) {
317 *err_msgp = "Selected config not in hashed nodes";
318 return -1;
319 }
320
321 /*
322 * Each node can generate one region for each sub-node. Allow for
323 * 7 sub-nodes (hash-1, signature-1, etc.) and some extra.
324 */
325 max_regions = 20 + count * 7;
326 struct fdt_region fdt_regions[max_regions];
327
328 /* Get a list of regions to hash */
329 count = fdt_find_regions(fit, node_inc, count,
330 exc_prop, ARRAY_SIZE(exc_prop),
331 fdt_regions, max_regions - 1,
332 path, sizeof(path), 0);
333 if (count < 0) {
334 *err_msgp = "Failed to hash configuration";
335 return -1;
336 }
337 if (count == 0) {
338 *err_msgp = "No data to hash";
339 return -1;
340 }
341 if (count >= max_regions - 1) {
342 *err_msgp = "Too many hash regions";
343 return -1;
344 }
345
346 /* Add the strings */
347 strings = fdt_getprop(fit, noffset, "hashed-strings", NULL);
348 if (strings) {
349 /*
350 * The strings region offset must be a static 0x0.
351 * This is set in tool/image-host.c
352 */
353 fdt_regions[count].offset = fdt_off_dt_strings(fit);
354 fdt_regions[count].size = fdt32_to_cpu(strings[1]);
355 count++;
356 }
357
358 /* Allocate the region list on the stack */
359 struct image_region region[count];
360
361 fit_region_make_list(fit, fdt_regions, count, region);
362 if (info.crypto->verify(&info, region, count, fit_value,
363 fit_value_len)) {
364 *err_msgp = "Verification failed";
365 return -1;
366 }
367
368 return 0;
369 }
370
fit_config_verify_sig(const void * fit,int conf_noffset,const void * sig_blob,int sig_offset)371 static int fit_config_verify_sig(const void *fit, int conf_noffset,
372 const void *sig_blob, int sig_offset)
373 {
374 int noffset;
375 char *err_msg = "No 'signature' subnode found";
376 int verified = 0;
377 int ret;
378
379 /* Process all hash subnodes of the component conf node */
380 fdt_for_each_subnode(noffset, fit, conf_noffset) {
381 const char *name = fit_get_name(fit, noffset, NULL);
382
383 if (!strncmp(name, FIT_SIG_NODENAME,
384 strlen(FIT_SIG_NODENAME))) {
385 ret = fit_config_check_sig(fit, noffset, sig_offset,
386 conf_noffset, &err_msg);
387 if (ret) {
388 puts("- ");
389 } else {
390 puts("+ ");
391 verified = 1;
392 break;
393 }
394 }
395 }
396
397 if (noffset == -FDT_ERR_TRUNCATED || noffset == -FDT_ERR_BADSTRUCTURE) {
398 err_msg = "Corrupted or truncated tree";
399 goto error;
400 }
401
402 if (verified)
403 return 0;
404
405 error:
406 printf(" error!\n%s for '%s' hash node in '%s' config node\n",
407 err_msg, fit_get_name(fit, noffset, NULL),
408 fit_get_name(fit, conf_noffset, NULL));
409 return -EPERM;
410 }
411
fit_config_verify_required_sigs(const void * fit,int conf_noffset,const void * sig_blob)412 static int fit_config_verify_required_sigs(const void *fit, int conf_noffset,
413 const void *sig_blob)
414 {
415 const char *name = fit_get_name(fit, conf_noffset, NULL);
416 int noffset;
417 int sig_node;
418 int verified = 0;
419 int reqd_sigs = 0;
420 bool reqd_policy_all = true;
421 const char *reqd_mode;
422
423 /*
424 * We don't support this since libfdt considers names with the
425 * name root but different @ suffix to be equal
426 */
427 if (strchr(name, '@')) {
428 printf("Configuration node '%s' contains '@'\n", name);
429 return -EPERM;
430 }
431
432 /* Work out what we need to verify */
433 sig_node = fdt_subnode_offset(sig_blob, 0, FIT_SIG_NODENAME);
434 if (sig_node < 0) {
435 debug("%s: No signature node found: %s\n", __func__,
436 fdt_strerror(sig_node));
437 return 0;
438 }
439
440 /* Get required-mode policy property from DTB */
441 reqd_mode = fdt_getprop(sig_blob, sig_node, "required-mode", NULL);
442 if (reqd_mode && !strcmp(reqd_mode, "any"))
443 reqd_policy_all = false;
444
445 debug("%s: required-mode policy set to '%s'\n", __func__,
446 reqd_policy_all ? "all" : "any");
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, FIT_KEY_REQUIRED,
453 NULL);
454 if (!required || strcmp(required, "conf"))
455 continue;
456
457 reqd_sigs++;
458
459 ret = fit_config_verify_sig(fit, conf_noffset, sig_blob,
460 noffset);
461 if (ret) {
462 if (reqd_policy_all) {
463 printf("Failed to verify required signature '%s'\n",
464 fit_get_name(sig_blob, noffset, NULL));
465 return ret;
466 }
467 } else {
468 verified++;
469 if (!reqd_policy_all)
470 break;
471 }
472 }
473
474 if (reqd_sigs && !verified) {
475 printf("Failed to verify 'any' of the required signature(s)\n");
476 return -EPERM;
477 }
478
479 return 0;
480 }
481
fit_config_verify(const void * fit,int conf_noffset)482 int fit_config_verify(const void *fit, int conf_noffset)
483 {
484 return fit_config_verify_required_sigs(fit, conf_noffset,
485 gd_fdt_blob());
486 }
487