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 padding_algo padding_algos[] = {
  75         {
  76                 .name = "pkcs-1.5",
  77                 .verify = padding_pkcs_15_verify,
  78         },
  79 #ifdef CONFIG_FIT_ENABLE_RSASSA_PSS_SUPPORT
  80         {
  81                 .name = "pss",
  82                 .verify = padding_pss_verify,
  83         }
  84 #endif /* CONFIG_FIT_ENABLE_RSASSA_PSS_SUPPORT */
  85 };
  86
  87 struct checksum_algo *image_get_checksum_algo(const char *full_name)
  88 {
  89         int i;
  90         const char *name;
  91
  92         for (i = 0; i < ARRAY_SIZE(checksum_algos); i++) {
  93                 name = checksum_algos[i].name;
  94                 /* Make sure names match and next char is a comma */
  95                 if (!strncmp(name, full_name, strlen(name)) &&
  96                     full_name[strlen(name)] == ',')
  97                         return &checksum_algos[i];
  98         }
  99
 100         return NULL;
 101 }
 102
 103 struct crypto_algo *image_get_crypto_algo(const char *full_name)
 104 {
 105         int i;
 106         const char *name;
 107
 108         /* Move name to after the comma */
 109         name = strchr(full_name, ',');
 110         if (!name)
 111                 return NULL;
 112         name += 1;
 113
 114         for (i = 0; i < ARRAY_SIZE(crypto_algos); i++) {
 115                 if (!strcmp(crypto_algos[i].name, name))
 116                         return &crypto_algos[i];
 117         }
 118
 119         return NULL;
 120 }
 121
 122 struct padding_algo *image_get_padding_algo(const char *name)
 123 {
 124         int i;
 125
 126         if (!name)
 127                 return NULL;
 128
 129         for (i = 0; i < ARRAY_SIZE(padding_algos); i++) {
 130                 if (!strcmp(padding_algos[i].name, name))
 131                         return &padding_algos[i];
 132         }
 133
 134         return NULL;
 135 }
 136
 137 /**
 138  * fit_region_make_list() - Make a list of image regions
 139  *
 140  * Given a list of fdt_regions, create a list of image_regions. This is a
 141  * simple conversion routine since the FDT and image code use different
 142  * structures.
 143  *
 144  * @fit: FIT image
 145  * @fdt_regions: Pointer to FDT regions
 146  * @count: Number of FDT regions
 147  * @region: Pointer to image regions, which must hold @count records. If
 148  * region is NULL, then (except for an SPL build) the array will be
 149  * allocated.
 150  * @return: Pointer to image regions
 151  */
 152 struct image_region *fit_region_make_list(const void *fit,
 153                 struct fdt_region *fdt_regions, int count,
 154                 struct image_region *region)
 155 {
 156         int i;
 157
 158         debug("Hash regions:\n");
 159         debug("%10s %10s\n", "Offset", "Size");
 160
 161         /*
 162          * Use malloc() except in SPL (to save code size). In SPL the caller
 163          * must allocate the array.
 164          */
 165 #ifndef CONFIG_SPL_BUILD
 166         if (!region)
 167                 region = calloc(sizeof(*region), count);
 168 #endif
 169         if (!region)
 170                 return NULL;
 171         for (i = 0; i < count; i++) {
 172                 debug("%10x %10x\n", fdt_regions[i].offset,
 173                       fdt_regions[i].size);
 174                 region[i].data = fit + fdt_regions[i].offset;
 175                 region[i].size = fdt_regions[i].size;
 176         }
 177
 178         return region;
 179 }
 180
 181 static int fit_image_setup_verify(struct image_sign_info *info,
 182                 const void *fit, int noffset, int required_keynode,
 183                 char **err_msgp)
 184 {
 185         char *algo_name;
 186         const char *padding_name;
 187
 188         if (fdt_totalsize(fit) > CONFIG_FIT_SIGNATURE_MAX_SIZE) {
 189                 *err_msgp = "Total size too large";
 190                 return 1;
 191         }
 192
 193         if (fit_image_hash_get_algo(fit, noffset, &algo_name)) {
 194                 *err_msgp = "Can't get hash algo property";
 195                 return -1;
 196         }
 197
 198         padding_name = fdt_getprop(fit, noffset, "padding", NULL);
 199         if (!padding_name)
 200                 padding_name = RSA_DEFAULT_PADDING_NAME;
 201
 202         memset(info, '\0', sizeof(*info));
 203         info->keyname = fdt_getprop(fit, noffset, "key-name-hint", NULL);
 204         info->fit = (void *)fit;
 205         info->node_offset = noffset;
 206         info->name = algo_name;
 207         info->checksum = image_get_checksum_algo(algo_name);
 208         info->crypto = image_get_crypto_algo(algo_name);
 209         info->padding = image_get_padding_algo(padding_name);
 210         info->fdt_blob = gd_fdt_blob();
 211         info->required_keynode = required_keynode;
 212         printf("%s:%s", algo_name, info->keyname);
 213
 214         if (!info->checksum || !info->crypto) {
 215                 *err_msgp = "Unknown signature algorithm";
 216                 return -1;
 217         }
 218
 219         return 0;
 220 }
 221
 222 int fit_image_check_sig(const void *fit, int noffset, const void *data,
 223                 size_t size, int required_keynode, char **err_msgp)
 224 {
 225         struct image_sign_info info;
 226         struct image_region region;
 227         uint8_t *fit_value;
 228         int fit_value_len;
 229
 230         *err_msgp = NULL;
 231         if (fit_image_setup_verify(&info, fit, noffset, required_keynode,
 232                                    err_msgp))
 233                 return -1;
 234
 235         if (fit_image_hash_get_value(fit, noffset, &fit_value,
 236                                      &fit_value_len)) {
 237                 *err_msgp = "Can't get hash value property";
 238                 return -1;
 239         }
 240
 241         region.data = data;
 242         region.size = size;
 243
 244         if (info.crypto->verify(&info, &region, 1, fit_value, fit_value_len)) {
 245                 *err_msgp = "Verification failed";
 246                 return -1;
 247         }
 248
 249         return 0;
 250 }
 251
 252 static int fit_image_verify_sig(const void *fit, int image_noffset,
 253                 const char *data, size_t size, const void *sig_blob,
 254                 int sig_offset)
 255 {
 256         int noffset;
 257         char *err_msg = "";
 258         int verified = 0;
 259         int ret;
 260
 261         /* Process all hash subnodes of the component image node */
 262         fdt_for_each_subnode(noffset, fit, image_noffset) {
 263                 const char *name = fit_get_name(fit, noffset, NULL);
 264
 265                 if (!strncmp(name, FIT_SIG_NODENAME,
 266                              strlen(FIT_SIG_NODENAME))) {
 267                         ret = fit_image_check_sig(fit, noffset, data,
 268                                                         size, -1, &err_msg);
 269                         if (ret) {
 270                                 puts("- ");
 271                         } else {
 272                                 puts("+ ");
 273                                 verified = 1;
 274                                 break;
 275                         }
 276                 }
 277         }
 278
 279         if (noffset == -FDT_ERR_TRUNCATED || noffset == -FDT_ERR_BADSTRUCTURE) {
 280                 err_msg = "Corrupted or truncated tree";
 281                 goto error;
 282         }
 283
 284         return verified ? 0 : -EPERM;
 285
 286 error:
 287         printf(" error!\n%s for '%s' hash node in '%s' image node\n",
 288                err_msg, fit_get_name(fit, noffset, NULL),
 289                fit_get_name(fit, image_noffset, NULL));
 290         return -1;
 291 }
 292
 293 int fit_image_verify_required_sigs(const void *fit, int image_noffset,
 294                 const char *data, size_t size, const void *sig_blob,
 295                 int *no_sigsp)
 296 {
 297         int verify_count = 0;
 298         int noffset;
 299         int sig_node;
 300
 301         /* Work out what we need to verify */
 302         *no_sigsp = 1;
 303         sig_node = fdt_subnode_offset(sig_blob, 0, FIT_SIG_NODENAME);
 304         if (sig_node < 0) {
 305                 debug("%s: No signature node found: %s\n", __func__,
 306                       fdt_strerror(sig_node));
 307                 return 0;
 308         }
 309
 310         fdt_for_each_subnode(noffset, sig_blob, sig_node) {
 311                 const char *required;
 312                 int ret;
 313
 314                 required = fdt_getprop(sig_blob, noffset, "required", NULL);
 315                 if (!required || strcmp(required, "image"))
 316                         continue;
 317                 ret = fit_image_verify_sig(fit, image_noffset, data, size,
 318                                         sig_blob, noffset);
 319                 if (ret) {
 320                         printf("Failed to verify required signature '%s'\n",
 321                                fit_get_name(sig_blob, noffset, NULL));
 322                         return ret;
 323                 }
 324                 verify_count++;
 325         }
 326
 327         if (verify_count)
 328                 *no_sigsp = 0;
 329
 330         return 0;
 331 }
 332
 333 int fit_config_check_sig(const void *fit, int noffset, int required_keynode,
 334                          char **err_msgp)
 335 {
 336         char * const exc_prop[] = {"data"};
 337         const char *prop, *end, *name;
 338         struct image_sign_info info;
 339         const uint32_t *strings;
 340         uint8_t *fit_value;
 341         int fit_value_len;
 342         int max_regions;
 343         int i, prop_len;
 344         char path[200];
 345         int count;
 346
 347         debug("%s: fdt=%p, conf='%s', sig='%s'\n", __func__, gd_fdt_blob(),
 348               fit_get_name(fit, noffset, NULL),
 349               fit_get_name(gd_fdt_blob(), required_keynode, NULL));
 350         *err_msgp = NULL;
 351         if (fit_image_setup_verify(&info, fit, noffset, required_keynode,
 352                                    err_msgp))
 353                 return -1;
 354
 355         if (fit_image_hash_get_value(fit, noffset, &fit_value,
 356                                      &fit_value_len)) {
 357                 *err_msgp = "Can't get hash value property";
 358                 return -1;
 359         }
 360
 361         /* Count the number of strings in the property */
 362         prop = fdt_getprop(fit, noffset, "hashed-nodes", &prop_len);
 363         end = prop ? prop + prop_len : prop;
 364         for (name = prop, count = 0; name < end; name++)
 365                 if (!*name)
 366                         count++;
 367         if (!count) {
 368                 *err_msgp = "Can't get hashed-nodes property";
 369                 return -1;
 370         }
 371
 372         if (prop && prop_len > 0 && prop[prop_len - 1] != '\0') {
 373                 *err_msgp = "hashed-nodes property must be null-terminated";
 374                 return -1;
 375         }
 376
 377         /* Add a sanity check here since we are using the stack */
 378         if (count > IMAGE_MAX_HASHED_NODES) {
 379                 *err_msgp = "Number of hashed nodes exceeds maximum";
 380                 return -1;
 381         }
 382
 383         /* Create a list of node names from those strings */
 384         char *node_inc[count];
 385
 386         debug("Hash nodes (%d):\n", count);
 387         for (name = prop, i = 0; name < end; name += strlen(name) + 1, i++) {
 388                 debug("   '%s'\n", name);
 389                 node_inc[i] = (char *)name;
 390         }
 391
 392         /*
 393          * Each node can generate one region for each sub-node. Allow for
 394          * 7 sub-nodes (hash-1, signature-1, etc.) and some extra.
 395          */
 396         max_regions = 20 + count * 7;
 397         struct fdt_region fdt_regions[max_regions];
 398
 399         /* Get a list of regions to hash */
 400         count = fdt_find_regions(fit, node_inc, count,
 401                         exc_prop, ARRAY_SIZE(exc_prop),
 402                         fdt_regions, max_regions - 1,
 403                         path, sizeof(path), 0);
 404         if (count < 0) {
 405                 *err_msgp = "Failed to hash configuration";
 406                 return -1;
 407         }
 408         if (count == 0) {
 409                 *err_msgp = "No data to hash";
 410                 return -1;
 411         }
 412         if (count >= max_regions - 1) {
 413                 *err_msgp = "Too many hash regions";
 414                 return -1;
 415         }
 416
 417         /* Add the strings */
 418         strings = fdt_getprop(fit, noffset, "hashed-strings", NULL);
 419         if (strings) {
 420                 /*
 421                  * The strings region offset must be a static 0x0.
 422                  * This is set in tool/image-host.c
 423                  */
 424                 fdt_regions[count].offset = fdt_off_dt_strings(fit);
 425                 fdt_regions[count].size = fdt32_to_cpu(strings[1]);
 426                 count++;
 427         }
 428
 429         /* Allocate the region list on the stack */
 430         struct image_region region[count];
 431
 432         fit_region_make_list(fit, fdt_regions, count, region);
 433         if (info.crypto->verify(&info, region, count, fit_value,
 434                                 fit_value_len)) {
 435                 *err_msgp = "Verification failed";
 436                 return -1;
 437         }
 438
 439         return 0;
 440 }
 441
 442 static int fit_config_verify_sig(const void *fit, int conf_noffset,
 443                 const void *sig_blob, int sig_offset)
 444 {
 445         int noffset;
 446         char *err_msg = "";
 447         int verified = 0;
 448         int ret;
 449
 450         /* Process all hash subnodes of the component conf node */
 451         fdt_for_each_subnode(noffset, fit, conf_noffset) {
 452                 const char *name = fit_get_name(fit, noffset, NULL);
 453
 454                 if (!strncmp(name, FIT_SIG_NODENAME,
 455                              strlen(FIT_SIG_NODENAME))) {
 456                         ret = fit_config_check_sig(fit, noffset, sig_offset,
 457                                                    &err_msg);
 458                         if (ret) {
 459                                 puts("- ");
 460                         } else {
 461                                 puts("+ ");
 462                                 verified = 1;
 463                                 break;
 464                         }
 465                 }
 466         }
 467
 468         if (noffset == -FDT_ERR_TRUNCATED || noffset == -FDT_ERR_BADSTRUCTURE) {
 469                 err_msg = "Corrupted or truncated tree";
 470                 goto error;
 471         }
 472
 473         return verified ? 0 : -EPERM;
 474
 475 error:
 476         printf(" error!\n%s for '%s' hash node in '%s' config node\n",
 477                err_msg, fit_get_name(fit, noffset, NULL),
 478                fit_get_name(fit, conf_noffset, NULL));
 479         return -1;
 480 }
 481
 482 int fit_config_verify_required_sigs(const void *fit, int conf_noffset,
 483                 const void *sig_blob)
 484 {
 485         int noffset;
 486         int sig_node;
 487
 488         /* Work out what we need to verify */
 489         sig_node = fdt_subnode_offset(sig_blob, 0, FIT_SIG_NODENAME);
 490         if (sig_node < 0) {
 491                 debug("%s: No signature node found: %s\n", __func__,
 492                       fdt_strerror(sig_node));
 493                 return 0;
 494         }
 495
 496         fdt_for_each_subnode(noffset, sig_blob, sig_node) {
 497                 const char *required;
 498                 int ret;
 499
 500                 required = fdt_getprop(sig_blob, noffset, "required", NULL);
 501                 if (!required || strcmp(required, "conf"))
 502                         continue;
 503                 ret = fit_config_verify_sig(fit, conf_noffset, sig_blob,
 504                                             noffset);
 505                 if (ret) {
 506                         printf("Failed to verify required signature '%s'\n",
 507                                fit_get_name(sig_blob, noffset, NULL));
 508                         return ret;
 509                 }
 510         }
 511
 512         return 0;
 513 }
 514
 515 int fit_config_verify(const void *fit, int conf_noffset)
 516 {
 517         return fit_config_verify_required_sigs(fit, conf_noffset,
 518                                                gd_fdt_blob());
 519 }