common/image-sig.c

   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 (fdt_totalsize(fit) > CONFIG_FIT_SIGNATURE_MAX_SIZE) {
 160                 *err_msgp = "Total size too large";
 161                 return 1;
 162         }
 163
 164         if (fit_image_hash_get_algo(fit, noffset, &algo_name)) {
 165                 *err_msgp = "Can't get hash algo property";
 166                 return -1;
 167         }
 168         memset(info, '\0', sizeof(*info));
 169         info->keyname = fdt_getprop(fit, noffset, "key-name-hint", NULL);
 170         info->fit = (void *)fit;
 171         info->node_offset = noffset;
 172         info->name = algo_name;
 173         info->checksum = image_get_checksum_algo(algo_name);
 174         info->crypto = image_get_crypto_algo(algo_name);
 175         info->fdt_blob = gd_fdt_blob();
 176         info->required_keynode = required_keynode;
 177         printf("%s:%s", algo_name, info->keyname);
 178
 179         if (!info->checksum || !info->crypto) {
 180                 *err_msgp = "Unknown signature algorithm";
 181                 return -1;
 182         }
 183
 184         return 0;
 185 }
 186
 187 int fit_image_check_sig(const void *fit, int noffset, const void *data,
 188                 size_t size, int required_keynode, char **err_msgp)
 189 {
 190         struct image_sign_info info;
 191         struct image_region region;
 192         uint8_t *fit_value;
 193         int fit_value_len;
 194
 195         *err_msgp = NULL;
 196         if (fit_image_setup_verify(&info, fit, noffset, required_keynode,
 197                                    err_msgp))
 198                 return -1;
 199
 200         if (fit_image_hash_get_value(fit, noffset, &fit_value,
 201                                      &fit_value_len)) {
 202                 *err_msgp = "Can't get hash value property";
 203                 return -1;
 204         }
 205
 206         region.data = data;
 207         region.size = size;
 208
 209         if (info.crypto->verify(&info, &region, 1, fit_value, fit_value_len)) {
 210                 *err_msgp = "Verification failed";
 211                 return -1;
 212         }
 213
 214         return 0;
 215 }
 216
 217 static int fit_image_verify_sig(const void *fit, int image_noffset,
 218                 const char *data, size_t size, const void *sig_blob,
 219                 int sig_offset)
 220 {
 221         int noffset;
 222         char *err_msg = "";
 223         int verified = 0;
 224         int ret;
 225
 226         /* Process all hash subnodes of the component image node */
 227         fdt_for_each_subnode(noffset, fit, image_noffset) {
 228                 const char *name = fit_get_name(fit, noffset, NULL);
 229
 230                 if (!strncmp(name, FIT_SIG_NODENAME,
 231                              strlen(FIT_SIG_NODENAME))) {
 232                         ret = fit_image_check_sig(fit, noffset, data,
 233                                                         size, -1, &err_msg);
 234                         if (ret) {
 235                                 puts("- ");
 236                         } else {
 237                                 puts("+ ");
 238                                 verified = 1;
 239                                 break;
 240                         }
 241                 }
 242         }
 243
 244         if (noffset == -FDT_ERR_TRUNCATED || noffset == -FDT_ERR_BADSTRUCTURE) {
 245                 err_msg = "Corrupted or truncated tree";
 246                 goto error;
 247         }
 248
 249         return verified ? 0 : -EPERM;
 250
 251 error:
 252         printf(" error!\n%s for '%s' hash node in '%s' image node\n",
 253                err_msg, fit_get_name(fit, noffset, NULL),
 254                fit_get_name(fit, image_noffset, NULL));
 255         return -1;
 256 }
 257
 258 int fit_image_verify_required_sigs(const void *fit, int image_noffset,
 259                 const char *data, size_t size, const void *sig_blob,
 260                 int *no_sigsp)
 261 {
 262         int verify_count = 0;
 263         int noffset;
 264         int sig_node;
 265
 266         /* Work out what we need to verify */
 267         *no_sigsp = 1;
 268         sig_node = fdt_subnode_offset(sig_blob, 0, FIT_SIG_NODENAME);
 269         if (sig_node < 0) {
 270                 debug("%s: No signature node found: %s\n", __func__,
 271                       fdt_strerror(sig_node));
 272                 return 0;
 273         }
 274
 275         fdt_for_each_subnode(noffset, sig_blob, sig_node) {
 276                 const char *required;
 277                 int ret;
 278
 279                 required = fdt_getprop(sig_blob, noffset, "required", NULL);
 280                 if (!required || strcmp(required, "image"))
 281                         continue;
 282                 ret = fit_image_verify_sig(fit, image_noffset, data, size,
 283                                         sig_blob, noffset);
 284                 if (ret) {
 285                         printf("Failed to verify required signature '%s'\n",
 286                                fit_get_name(sig_blob, noffset, NULL));
 287                         return ret;
 288                 }
 289                 verify_count++;
 290         }
 291
 292         if (verify_count)
 293                 *no_sigsp = 0;
 294
 295         return 0;
 296 }
 297
 298 int fit_config_check_sig(const void *fit, int noffset, int required_keynode,
 299                          char **err_msgp)
 300 {
 301         char * const exc_prop[] = {"data"};
 302         const char *prop, *end, *name;
 303         struct image_sign_info info;
 304         const uint32_t *strings;
 305         uint8_t *fit_value;
 306         int fit_value_len;
 307         int max_regions;
 308         int i, prop_len;
 309         char path[200];
 310         int count;
 311
 312         debug("%s: fdt=%p, conf='%s', sig='%s'\n", __func__, gd_fdt_blob(),
 313               fit_get_name(fit, noffset, NULL),
 314               fit_get_name(gd_fdt_blob(), required_keynode, NULL));
 315         *err_msgp = NULL;
 316         if (fit_image_setup_verify(&info, fit, noffset, required_keynode,
 317                                    err_msgp))
 318                 return -1;
 319
 320         if (fit_image_hash_get_value(fit, noffset, &fit_value,
 321                                      &fit_value_len)) {
 322                 *err_msgp = "Can't get hash value property";
 323                 return -1;
 324         }
 325
 326         /* Count the number of strings in the property */
 327         prop = fdt_getprop(fit, noffset, "hashed-nodes", &prop_len);
 328         end = prop ? prop + prop_len : prop;
 329         for (name = prop, count = 0; name < end; name++)
 330                 if (!*name)
 331                         count++;
 332         if (!count) {
 333                 *err_msgp = "Can't get hashed-nodes property";
 334                 return -1;
 335         }
 336
 337         /* Add a sanity check here since we are using the stack */
 338         if (count > IMAGE_MAX_HASHED_NODES) {
 339                 *err_msgp = "Number of hashed nodes exceeds maximum";
 340                 return -1;
 341         }
 342
 343         /* Create a list of node names from those strings */
 344         char *node_inc[count];
 345
 346         debug("Hash nodes (%d):\n", count);
 347         for (name = prop, i = 0; name < end; name += strlen(name) + 1, i++) {
 348                 debug("   '%s'\n", name);
 349                 node_inc[i] = (char *)name;
 350         }
 351
 352         /*
 353          * Each node can generate one region for each sub-node. Allow for
 354          * 7 sub-nodes (hash-1, signature-1, etc.) and some extra.
 355          */
 356         max_regions = 20 + count * 7;
 357         struct fdt_region fdt_regions[max_regions];
 358
 359         /* Get a list of regions to hash */
 360         count = fdt_find_regions(fit, node_inc, count,
 361                         exc_prop, ARRAY_SIZE(exc_prop),
 362                         fdt_regions, max_regions - 1,
 363                         path, sizeof(path), 0);
 364         if (count < 0) {
 365                 *err_msgp = "Failed to hash configuration";
 366                 return -1;
 367         }
 368         if (count == 0) {
 369                 *err_msgp = "No data to hash";
 370                 return -1;
 371         }
 372         if (count >= max_regions - 1) {
 373                 *err_msgp = "Too many hash regions";
 374                 return -1;
 375         }
 376
 377         /* Add the strings */
 378         strings = fdt_getprop(fit, noffset, "hashed-strings", NULL);
 379         if (strings) {
 380                 /*
 381                  * The strings region offset must be a static 0x0.
 382                  * This is set in tool/image-host.c
 383                  */
 384                 fdt_regions[count].offset = fdt_off_dt_strings(fit);
 385                 fdt_regions[count].size = fdt32_to_cpu(strings[1]);
 386                 count++;
 387         }
 388
 389         /* Allocate the region list on the stack */
 390         struct image_region region[count];
 391
 392         fit_region_make_list(fit, fdt_regions, count, region);
 393         if (info.crypto->verify(&info, region, count, fit_value,
 394                                 fit_value_len)) {
 395                 *err_msgp = "Verification failed";
 396                 return -1;
 397         }
 398
 399         return 0;
 400 }
 401
 402 static int fit_config_verify_sig(const void *fit, int conf_noffset,
 403                 const void *sig_blob, int sig_offset)
 404 {
 405         int noffset;
 406         char *err_msg = "";
 407         int verified = 0;
 408         int ret;
 409
 410         /* Process all hash subnodes of the component conf node */
 411         fdt_for_each_subnode(noffset, fit, conf_noffset) {
 412                 const char *name = fit_get_name(fit, noffset, NULL);
 413
 414                 if (!strncmp(name, FIT_SIG_NODENAME,
 415                              strlen(FIT_SIG_NODENAME))) {
 416                         ret = fit_config_check_sig(fit, noffset, sig_offset,
 417                                                    &err_msg);
 418                         if (ret) {
 419                                 puts("- ");
 420                         } else {
 421                                 puts("+ ");
 422                                 verified = 1;
 423                                 break;
 424                         }
 425                 }
 426         }
 427
 428         if (noffset == -FDT_ERR_TRUNCATED || noffset == -FDT_ERR_BADSTRUCTURE) {
 429                 err_msg = "Corrupted or truncated tree";
 430                 goto error;
 431         }
 432
 433         return verified ? 0 : -EPERM;
 434
 435 error:
 436         printf(" error!\n%s for '%s' hash node in '%s' config node\n",
 437                err_msg, fit_get_name(fit, noffset, NULL),
 438                fit_get_name(fit, conf_noffset, NULL));
 439         return -1;
 440 }
 441
 442 int fit_config_verify_required_sigs(const void *fit, int conf_noffset,
 443                 const void *sig_blob)
 444 {
 445         int noffset;
 446         int sig_node;
 447
 448         /* Work out what we need to verify */
 449         sig_node = fdt_subnode_offset(sig_blob, 0, FIT_SIG_NODENAME);
 450         if (sig_node < 0) {
 451                 debug("%s: No signature node found: %s\n", __func__,
 452                       fdt_strerror(sig_node));
 453                 return 0;
 454         }
 455
 456         fdt_for_each_subnode(noffset, sig_blob, sig_node) {
 457                 const char *required;
 458                 int ret;
 459
 460                 required = fdt_getprop(sig_blob, noffset, "required", NULL);
 461                 if (!required || strcmp(required, "conf"))
 462                         continue;
 463                 ret = fit_config_verify_sig(fit, conf_noffset, sig_blob,
 464                                             noffset);
 465                 if (ret) {
 466                         printf("Failed to verify required signature '%s'\n",
 467                                fit_get_name(sig_blob, noffset, NULL));
 468                         return ret;
 469                 }
 470         }
 471
 472         return 0;
 473 }
 474
 475 int fit_config_verify(const void *fit, int conf_noffset)
 476 {
 477         return fit_config_verify_required_sigs(fit, conf_noffset,
 478                                                gd_fdt_blob());
 479 }