common/image-sig.c

   1 /*
   2  * Copyright (c) 2013, Google Inc.
   3  *
   4  * SPDX-License-Identifier:     GPL-2.0+
   5  */
   6
   7 #ifdef USE_HOSTCC
   8 #include "mkimage.h"
   9 #include <time.h>
  10 #else
  11 #include <common.h>
  12 #include <malloc.h>
  13 DECLARE_GLOBAL_DATA_PTR;
  14 #endif /* !USE_HOSTCC*/
  15 #include <image.h>
  16 #include <u-boot/rsa.h>
  17 #include <u-boot/rsa-checksum.h>
  18
  19 #define IMAGE_MAX_HASHED_NODES          100
  20
  21 #ifdef USE_HOSTCC
  22 void *host_blob;
  23 void image_set_host_blob(void *blob)
  24 {
  25         host_blob = blob;
  26 }
  27 void *image_get_host_blob(void)
  28 {
  29         return host_blob;
  30 }
  31 #endif
  32
  33 struct checksum_algo checksum_algos[] = {
  34         {
  35                 "sha1",
  36                 SHA1_SUM_LEN,
  37                 RSA2048_BYTES,
  38 #if IMAGE_ENABLE_SIGN
  39                 EVP_sha1,
  40 #endif
  41                 hash_calculate,
  42                 padding_sha1_rsa2048,
  43         },
  44         {
  45                 "sha256",
  46                 SHA256_SUM_LEN,
  47                 RSA2048_BYTES,
  48 #if IMAGE_ENABLE_SIGN
  49                 EVP_sha256,
  50 #endif
  51                 hash_calculate,
  52                 padding_sha256_rsa2048,
  53         },
  54         {
  55                 "sha256",
  56                 SHA256_SUM_LEN,
  57                 RSA4096_BYTES,
  58 #if IMAGE_ENABLE_SIGN
  59                 EVP_sha256,
  60 #endif
  61                 hash_calculate,
  62                 padding_sha256_rsa4096,
  63         }
  64
  65 };
  66
  67 struct image_sig_algo image_sig_algos[] = {
  68         {
  69                 "sha1,rsa2048",
  70                 rsa_sign,
  71                 rsa_add_verify_data,
  72                 rsa_verify,
  73                 &checksum_algos[0],
  74         },
  75         {
  76                 "sha256,rsa2048",
  77                 rsa_sign,
  78                 rsa_add_verify_data,
  79                 rsa_verify,
  80                 &checksum_algos[1],
  81         },
  82         {
  83                 "sha256,rsa4096",
  84                 rsa_sign,
  85                 rsa_add_verify_data,
  86                 rsa_verify,
  87                 &checksum_algos[2],
  88         }
  89
  90 };
  91
  92 struct image_sig_algo *image_get_sig_algo(const char *name)
  93 {
  94         int i;
  95
  96         for (i = 0; i < ARRAY_SIZE(image_sig_algos); i++) {
  97                 if (!strcmp(image_sig_algos[i].name, name))
  98                         return &image_sig_algos[i];
  99         }
 100
 101         return NULL;
 102 }
 103
 104 /**
 105  * fit_region_make_list() - Make a list of image regions
 106  *
 107  * Given a list of fdt_regions, create a list of image_regions. This is a
 108  * simple conversion routine since the FDT and image code use different
 109  * structures.
 110  *
 111  * @fit: FIT image
 112  * @fdt_regions: Pointer to FDT regions
 113  * @count: Number of FDT regions
 114  * @region: Pointer to image regions, which must hold @count records. If
 115  * region is NULL, then (except for an SPL build) the array will be
 116  * allocated.
 117  * @return: Pointer to image regions
 118  */
 119 struct image_region *fit_region_make_list(const void *fit,
 120                 struct fdt_region *fdt_regions, int count,
 121                 struct image_region *region)
 122 {
 123         int i;
 124
 125         debug("Hash regions:\n");
 126         debug("%10s %10s\n", "Offset", "Size");
 127
 128         /*
 129          * Use malloc() except in SPL (to save code size). In SPL the caller
 130          * must allocate the array.
 131          */
 132 #ifndef CONFIG_SPL_BUILD
 133         if (!region)
 134                 region = calloc(sizeof(*region), count);
 135 #endif
 136         if (!region)
 137                 return NULL;
 138         for (i = 0; i < count; i++) {
 139                 debug("%10x %10x\n", fdt_regions[i].offset,
 140                       fdt_regions[i].size);
 141                 region[i].data = fit + fdt_regions[i].offset;
 142                 region[i].size = fdt_regions[i].size;
 143         }
 144
 145         return region;
 146 }
 147
 148 static int fit_image_setup_verify(struct image_sign_info *info,
 149                 const void *fit, int noffset, int required_keynode,
 150                 char **err_msgp)
 151 {
 152         char *algo_name;
 153
 154         if (fit_image_hash_get_algo(fit, noffset, &algo_name)) {
 155                 *err_msgp = "Can't get hash algo property";
 156                 return -1;
 157         }
 158         memset(info, '\0', sizeof(*info));
 159         info->keyname = fdt_getprop(fit, noffset, "key-name-hint", NULL);
 160         info->fit = (void *)fit;
 161         info->node_offset = noffset;
 162         info->algo = image_get_sig_algo(algo_name);
 163         info->fdt_blob = gd_fdt_blob();
 164         info->required_keynode = required_keynode;
 165         printf("%s:%s", algo_name, info->keyname);
 166
 167         if (!info->algo) {
 168                 *err_msgp = "Unknown signature algorithm";
 169                 return -1;
 170         }
 171
 172         return 0;
 173 }
 174
 175 int fit_image_check_sig(const void *fit, int noffset, const void *data,
 176                 size_t size, int required_keynode, char **err_msgp)
 177 {
 178         struct image_sign_info info;
 179         struct image_region region;
 180         uint8_t *fit_value;
 181         int fit_value_len;
 182
 183         *err_msgp = NULL;
 184         if (fit_image_setup_verify(&info, fit, noffset, required_keynode,
 185                                    err_msgp))
 186                 return -1;
 187
 188         if (fit_image_hash_get_value(fit, noffset, &fit_value,
 189                                      &fit_value_len)) {
 190                 *err_msgp = "Can't get hash value property";
 191                 return -1;
 192         }
 193
 194         region.data = data;
 195         region.size = size;
 196
 197         if (info.algo->verify(&info, &region, 1, fit_value, fit_value_len)) {
 198                 *err_msgp = "Verification failed";
 199                 return -1;
 200         }
 201
 202         return 0;
 203 }
 204
 205 static int fit_image_verify_sig(const void *fit, int image_noffset,
 206                 const char *data, size_t size, const void *sig_blob,
 207                 int sig_offset)
 208 {
 209         int noffset;
 210         char *err_msg = "";
 211         int verified = 0;
 212         int ret;
 213
 214         /* Process all hash subnodes of the component image node */
 215         for (noffset = fdt_first_subnode(fit, image_noffset);
 216              noffset >= 0;
 217              noffset = fdt_next_subnode(fit, noffset)) {
 218                 const char *name = fit_get_name(fit, noffset, NULL);
 219
 220                 if (!strncmp(name, FIT_SIG_NODENAME,
 221                              strlen(FIT_SIG_NODENAME))) {
 222                         ret = fit_image_check_sig(fit, noffset, data,
 223                                                         size, -1, &err_msg);
 224                         if (ret) {
 225                                 puts("- ");
 226                         } else {
 227                                 puts("+ ");
 228                                 verified = 1;
 229                                 break;
 230                         }
 231                 }
 232         }
 233
 234         if (noffset == -FDT_ERR_TRUNCATED || noffset == -FDT_ERR_BADSTRUCTURE) {
 235                 err_msg = "Corrupted or truncated tree";
 236                 goto error;
 237         }
 238
 239         return verified ? 0 : -EPERM;
 240
 241 error:
 242         printf(" error!\n%s for '%s' hash node in '%s' image node\n",
 243                err_msg, fit_get_name(fit, noffset, NULL),
 244                fit_get_name(fit, image_noffset, NULL));
 245         return -1;
 246 }
 247
 248 int fit_image_verify_required_sigs(const void *fit, int image_noffset,
 249                 const char *data, size_t size, const void *sig_blob,
 250                 int *no_sigsp)
 251 {
 252         int verify_count = 0;
 253         int noffset;
 254         int sig_node;
 255
 256         /* Work out what we need to verify */
 257         *no_sigsp = 1;
 258         sig_node = fdt_subnode_offset(sig_blob, 0, FIT_SIG_NODENAME);
 259         if (sig_node < 0) {
 260                 debug("%s: No signature node found: %s\n", __func__,
 261                       fdt_strerror(sig_node));
 262                 return 0;
 263         }
 264
 265         for (noffset = fdt_first_subnode(sig_blob, sig_node);
 266              noffset >= 0;
 267              noffset = fdt_next_subnode(sig_blob, noffset)) {
 268                 const char *required;
 269                 int ret;
 270
 271                 required = fdt_getprop(sig_blob, noffset, "required", NULL);
 272                 if (!required || strcmp(required, "image"))
 273                         continue;
 274                 ret = fit_image_verify_sig(fit, image_noffset, data, size,
 275                                         sig_blob, noffset);
 276                 if (ret) {
 277                         printf("Failed to verify required signature '%s'\n",
 278                                fit_get_name(sig_blob, noffset, NULL));
 279                         return ret;
 280                 }
 281                 verify_count++;
 282         }
 283
 284         if (verify_count)
 285                 *no_sigsp = 0;
 286
 287         return 0;
 288 }
 289
 290 int fit_config_check_sig(const void *fit, int noffset, int required_keynode,
 291                          char **err_msgp)
 292 {
 293         char * const exc_prop[] = {"data"};
 294         const char *prop, *end, *name;
 295         struct image_sign_info info;
 296         const uint32_t *strings;
 297         uint8_t *fit_value;
 298         int fit_value_len;
 299         int max_regions;
 300         int i, prop_len;
 301         char path[200];
 302         int count;
 303
 304         debug("%s: fdt=%p, conf='%s', sig='%s'\n", __func__, gd_fdt_blob(),
 305               fit_get_name(fit, noffset, NULL),
 306               fit_get_name(gd_fdt_blob(), required_keynode, NULL));
 307         *err_msgp = NULL;
 308         if (fit_image_setup_verify(&info, fit, noffset, required_keynode,
 309                                    err_msgp))
 310                 return -1;
 311
 312         if (fit_image_hash_get_value(fit, noffset, &fit_value,
 313                                      &fit_value_len)) {
 314                 *err_msgp = "Can't get hash value property";
 315                 return -1;
 316         }
 317
 318         /* Count the number of strings in the property */
 319         prop = fdt_getprop(fit, noffset, "hashed-nodes", &prop_len);
 320         end = prop ? prop + prop_len : prop;
 321         for (name = prop, count = 0; name < end; name++)
 322                 if (!*name)
 323                         count++;
 324         if (!count) {
 325                 *err_msgp = "Can't get hashed-nodes property";
 326                 return -1;
 327         }
 328
 329         /* Add a sanity check here since we are using the stack */
 330         if (count > IMAGE_MAX_HASHED_NODES) {
 331                 *err_msgp = "Number of hashed nodes exceeds maximum";
 332                 return -1;
 333         }
 334
 335         /* Create a list of node names from those strings */
 336         char *node_inc[count];
 337
 338         debug("Hash nodes (%d):\n", count);
 339         for (name = prop, i = 0; name < end; name += strlen(name) + 1, i++) {
 340                 debug("   '%s'\n", name);
 341                 node_inc[i] = (char *)name;
 342         }
 343
 344         /*
 345          * Each node can generate one region for each sub-node. Allow for
 346          * 7 sub-nodes (hash@1, signature@1, etc.) and some extra.
 347          */
 348         max_regions = 20 + count * 7;
 349         struct fdt_region fdt_regions[max_regions];
 350
 351         /* Get a list of regions to hash */
 352         count = fdt_find_regions(fit, node_inc, count,
 353                         exc_prop, ARRAY_SIZE(exc_prop),
 354                         fdt_regions, max_regions - 1,
 355                         path, sizeof(path), 0);
 356         if (count < 0) {
 357                 *err_msgp = "Failed to hash configuration";
 358                 return -1;
 359         }
 360         if (count == 0) {
 361                 *err_msgp = "No data to hash";
 362                 return -1;
 363         }
 364         if (count >= max_regions - 1) {
 365                 *err_msgp = "Too many hash regions";
 366                 return -1;
 367         }
 368
 369         /* Add the strings */
 370         strings = fdt_getprop(fit, noffset, "hashed-strings", NULL);
 371         if (strings) {
 372                 fdt_regions[count].offset = fdt_off_dt_strings(fit) +
 373                                 fdt32_to_cpu(strings[0]);
 374                 fdt_regions[count].size = fdt32_to_cpu(strings[1]);
 375                 count++;
 376         }
 377
 378         /* Allocate the region list on the stack */
 379         struct image_region region[count];
 380
 381         fit_region_make_list(fit, fdt_regions, count, region);
 382         if (info.algo->verify(&info, region, count, fit_value,
 383                               fit_value_len)) {
 384                 *err_msgp = "Verification failed";
 385                 return -1;
 386         }
 387
 388         return 0;
 389 }
 390
 391 static int fit_config_verify_sig(const void *fit, int conf_noffset,
 392                 const void *sig_blob, int sig_offset)
 393 {
 394         int noffset;
 395         char *err_msg = "";
 396         int verified = 0;
 397         int ret;
 398
 399         /* Process all hash subnodes of the component conf node */
 400         for (noffset = fdt_first_subnode(fit, conf_noffset);
 401              noffset >= 0;
 402              noffset = fdt_next_subnode(fit, noffset)) {
 403                 const char *name = fit_get_name(fit, noffset, NULL);
 404
 405                 if (!strncmp(name, FIT_SIG_NODENAME,
 406                              strlen(FIT_SIG_NODENAME))) {
 407                         ret = fit_config_check_sig(fit, noffset, sig_offset,
 408                                                    &err_msg);
 409                         if (ret) {
 410                                 puts("- ");
 411                         } else {
 412                                 puts("+ ");
 413                                 verified = 1;
 414                                 break;
 415                         }
 416                 }
 417         }
 418
 419         if (noffset == -FDT_ERR_TRUNCATED || noffset == -FDT_ERR_BADSTRUCTURE) {
 420                 err_msg = "Corrupted or truncated tree";
 421                 goto error;
 422         }
 423
 424         return verified ? 0 : -EPERM;
 425
 426 error:
 427         printf(" error!\n%s for '%s' hash node in '%s' config node\n",
 428                err_msg, fit_get_name(fit, noffset, NULL),
 429                fit_get_name(fit, conf_noffset, NULL));
 430         return -1;
 431 }
 432
 433 int fit_config_verify_required_sigs(const void *fit, int conf_noffset,
 434                 const void *sig_blob)
 435 {
 436         int noffset;
 437         int sig_node;
 438
 439         /* Work out what we need to verify */
 440         sig_node = fdt_subnode_offset(sig_blob, 0, FIT_SIG_NODENAME);
 441         if (sig_node < 0) {
 442                 debug("%s: No signature node found: %s\n", __func__,
 443                       fdt_strerror(sig_node));
 444                 return 0;
 445         }
 446
 447         for (noffset = fdt_first_subnode(sig_blob, sig_node);
 448              noffset >= 0;
 449              noffset = fdt_next_subnode(sig_blob, noffset)) {
 450                 const char *required;
 451                 int ret;
 452
 453                 required = fdt_getprop(sig_blob, noffset, "required", NULL);
 454                 if (!required || strcmp(required, "conf"))
 455                         continue;
 456                 ret = fit_config_verify_sig(fit, conf_noffset, sig_blob,
 457                                             noffset);
 458                 if (ret) {
 459                         printf("Failed to verify required signature '%s'\n",
 460                                fit_get_name(sig_blob, noffset, NULL));
 461                         return ret;
 462                 }
 463         }
 464
 465         return 0;
 466 }
 467
 468 int fit_config_verify(const void *fit, int conf_noffset)
 469 {
 470         return fit_config_verify_required_sigs(fit, conf_noffset,
 471                                                gd_fdt_blob());
 472 }