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