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                 .name = "sha1",
  36                 .checksum_len = SHA1_SUM_LEN,
  37                 .der_len = SHA1_DER_LEN,
  38                 .der_prefix = sha1_der_prefix,
  39 #if IMAGE_ENABLE_SIGN
  40                 .calculate_sign = EVP_sha1,
  41 #endif
  42                 .calculate = hash_calculate,
  43         },
  44         {
  45                 .name = "sha256",
  46                 .checksum_len = SHA256_SUM_LEN,
  47                 .der_len = SHA256_DER_LEN,
  48                 .der_prefix = sha256_der_prefix,
  49 #if IMAGE_ENABLE_SIGN
  50                 .calculate_sign = EVP_sha256,
  51 #endif
  52                 .calculate = hash_calculate,
  53         }
  54
  55 };
  56
  57 struct crypto_algo crypto_algos[] = {
  58         {
  59                 .name = "rsa2048",
  60                 .key_len = RSA2048_BYTES,
  61                 .sign = rsa_sign,
  62                 .add_verify_data = rsa_add_verify_data,
  63                 .verify = rsa_verify,
  64         },
  65         {
  66                 .name = "rsa4096",
  67                 .key_len = RSA4096_BYTES,
  68                 .sign = rsa_sign,
  69                 .add_verify_data = rsa_add_verify_data,
  70                 .verify = rsa_verify,
  71         }
  72
  73 };
  74
  75 struct checksum_algo *image_get_checksum_algo(const char *full_name)
  76 {
  77         int i;
  78         const char *name;
  79
  80         for (i = 0; i < ARRAY_SIZE(checksum_algos); i++) {
  81                 name = checksum_algos[i].name;
  82                 /* Make sure names match and next char is a comma */
  83                 if (!strncmp(name, full_name, strlen(name)) &&
  84                     full_name[strlen(name)] == ',')
  85                         return &checksum_algos[i];
  86         }
  87
  88         return NULL;
  89 }
  90
  91 struct crypto_algo *image_get_crypto_algo(const char *full_name)
  92 {
  93         int i;
  94         const char *name;
  95
  96         /* Move name to after the comma */
  97         name = strchr(full_name, ',');
  98         if (!name)
  99                 return NULL;
 100         name += 1;
 101
 102         for (i = 0; i < ARRAY_SIZE(crypto_algos); i++) {
 103                 if (!strcmp(crypto_algos[i].name, name))
 104                         return &crypto_algos[i];
 105         }
 106
 107         return NULL;
 108 }
 109
 110 /**
 111  * fit_region_make_list() - Make a list of image regions
 112  *
 113  * Given a list of fdt_regions, create a list of image_regions. This is a
 114  * simple conversion routine since the FDT and image code use different
 115  * structures.
 116  *
 117  * @fit: FIT image
 118  * @fdt_regions: Pointer to FDT regions
 119  * @count: Number of FDT regions
 120  * @region: Pointer to image regions, which must hold @count records. If
 121  * region is NULL, then (except for an SPL build) the array will be
 122  * allocated.
 123  * @return: Pointer to image regions
 124  */
 125 struct image_region *fit_region_make_list(const void *fit,
 126                 struct fdt_region *fdt_regions, int count,
 127                 struct image_region *region)
 128 {
 129         int i;
 130
 131         debug("Hash regions:\n");
 132         debug("%10s %10s\n", "Offset", "Size");
 133
 134         /*
 135          * Use malloc() except in SPL (to save code size). In SPL the caller
 136          * must allocate the array.
 137          */
 138 #ifndef CONFIG_SPL_BUILD
 139         if (!region)
 140                 region = calloc(sizeof(*region), count);
 141 #endif
 142         if (!region)
 143                 return NULL;
 144         for (i = 0; i < count; i++) {
 145                 debug("%10x %10x\n", fdt_regions[i].offset,
 146                       fdt_regions[i].size);
 147                 region[i].data = fit + fdt_regions[i].offset;
 148                 region[i].size = fdt_regions[i].size;
 149         }
 150
 151         return region;
 152 }
 153
 154 static int fit_image_setup_verify(struct image_sign_info *info,
 155                 const void *fit, int noffset, int required_keynode,
 156                 char **err_msgp)
 157 {
 158         char *algo_name;
 159
 160         if (fit_image_hash_get_algo(fit, noffset, &algo_name)) {
 161                 *err_msgp = "Can't get hash algo property";
 162                 return -1;
 163         }
 164         memset(info, '\0', sizeof(*info));
 165         info->keyname = fdt_getprop(fit, noffset, "key-name-hint", NULL);
 166         info->fit = (void *)fit;
 167         info->node_offset = noffset;
 168         info->name = algo_name;
 169         info->checksum = image_get_checksum_algo(algo_name);
 170         info->crypto = image_get_crypto_algo(algo_name);
 171         info->fdt_blob = gd_fdt_blob();
 172         info->required_keynode = required_keynode;
 173         printf("%s:%s", algo_name, info->keyname);
 174
 175         if (!info->checksum || !info->crypto) {
 176                 *err_msgp = "Unknown signature algorithm";
 177                 return -1;
 178         }
 179
 180         return 0;
 181 }
 182
 183 int fit_image_check_sig(const void *fit, int noffset, const void *data,
 184                 size_t size, int required_keynode, char **err_msgp)
 185 {
 186         struct image_sign_info info;
 187         struct image_region region;
 188         uint8_t *fit_value;
 189         int fit_value_len;
 190
 191         *err_msgp = NULL;
 192         if (fit_image_setup_verify(&info, fit, noffset, required_keynode,
 193                                    err_msgp))
 194                 return -1;
 195
 196         if (fit_image_hash_get_value(fit, noffset, &fit_value,
 197                                      &fit_value_len)) {
 198                 *err_msgp = "Can't get hash value property";
 199                 return -1;
 200         }
 201
 202         region.data = data;
 203         region.size = size;
 204
 205         if (info.crypto->verify(&info, &region, 1, fit_value, fit_value_len)) {
 206                 *err_msgp = "Verification failed";
 207                 return -1;
 208         }
 209
 210         return 0;
 211 }
 212
 213 static int fit_image_verify_sig(const void *fit, int image_noffset,
 214                 const char *data, size_t size, const void *sig_blob,
 215                 int sig_offset)
 216 {
 217         int noffset;
 218         char *err_msg = "";
 219         int verified = 0;
 220         int ret;
 221
 222         /* Process all hash subnodes of the component image node */
 223         fdt_for_each_subnode(noffset, fit, image_noffset) {
 224                 const char *name = fit_get_name(fit, noffset, NULL);
 225
 226                 if (!strncmp(name, FIT_SIG_NODENAME,
 227                              strlen(FIT_SIG_NODENAME))) {
 228                         ret = fit_image_check_sig(fit, noffset, data,
 229                                                         size, -1, &err_msg);
 230                         if (ret) {
 231                                 puts("- ");
 232                         } else {
 233                                 puts("+ ");
 234                                 verified = 1;
 235                                 break;
 236                         }
 237                 }
 238         }
 239
 240         if (noffset == -FDT_ERR_TRUNCATED || noffset == -FDT_ERR_BADSTRUCTURE) {
 241                 err_msg = "Corrupted or truncated tree";
 242                 goto error;
 243         }
 244
 245         return verified ? 0 : -EPERM;
 246
 247 error:
 248         printf(" error!\n%s for '%s' hash node in '%s' image node\n",
 249                err_msg, fit_get_name(fit, noffset, NULL),
 250                fit_get_name(fit, image_noffset, NULL));
 251         return -1;
 252 }
 253
 254 int fit_image_verify_required_sigs(const void *fit, int image_noffset,
 255                 const char *data, size_t size, const void *sig_blob,
 256                 int *no_sigsp)
 257 {
 258         int verify_count = 0;
 259         int noffset;
 260         int sig_node;
 261
 262         /* Work out what we need to verify */
 263         *no_sigsp = 1;
 264         sig_node = fdt_subnode_offset(sig_blob, 0, FIT_SIG_NODENAME);
 265         if (sig_node < 0) {
 266                 debug("%s: No signature node found: %s\n", __func__,
 267                       fdt_strerror(sig_node));
 268                 return 0;
 269         }
 270
 271         fdt_for_each_subnode(noffset, sig_blob, sig_node) {
 272                 const char *required;
 273                 int ret;
 274
 275                 required = fdt_getprop(sig_blob, noffset, "required", NULL);
 276                 if (!required || strcmp(required, "image"))
 277                         continue;
 278                 ret = fit_image_verify_sig(fit, image_noffset, data, size,
 279                                         sig_blob, noffset);
 280                 if (ret) {
 281                         printf("Failed to verify required signature '%s'\n",
 282                                fit_get_name(sig_blob, noffset, NULL));
 283                         return ret;
 284                 }
 285                 verify_count++;
 286         }
 287
 288         if (verify_count)
 289                 *no_sigsp = 0;
 290
 291         return 0;
 292 }
 293
 294 int fit_config_check_sig(const void *fit, int noffset, int required_keynode,
 295                          char **err_msgp)
 296 {
 297         char * const exc_prop[] = {"data"};
 298         const char *prop, *end, *name;
 299         struct image_sign_info info;
 300         const uint32_t *strings;
 301         uint8_t *fit_value;
 302         int fit_value_len;
 303         int max_regions;
 304         int i, prop_len;
 305         char path[200];
 306         int count;
 307
 308         debug("%s: fdt=%p, conf='%s', sig='%s'\n", __func__, gd_fdt_blob(),
 309               fit_get_name(fit, noffset, NULL),
 310               fit_get_name(gd_fdt_blob(), required_keynode, NULL));
 311         *err_msgp = NULL;
 312         if (fit_image_setup_verify(&info, fit, noffset, required_keynode,
 313                                    err_msgp))
 314                 return -1;
 315
 316         if (fit_image_hash_get_value(fit, noffset, &fit_value,
 317                                      &fit_value_len)) {
 318                 *err_msgp = "Can't get hash value property";
 319                 return -1;
 320         }
 321
 322         /* Count the number of strings in the property */
 323         prop = fdt_getprop(fit, noffset, "hashed-nodes", &prop_len);
 324         end = prop ? prop + prop_len : prop;
 325         for (name = prop, count = 0; name < end; name++)
 326                 if (!*name)
 327                         count++;
 328         if (!count) {
 329                 *err_msgp = "Can't get hashed-nodes property";
 330                 return -1;
 331         }
 332
 333         /* Add a sanity check here since we are using the stack */
 334         if (count > IMAGE_MAX_HASHED_NODES) {
 335                 *err_msgp = "Number of hashed nodes exceeds maximum";
 336                 return -1;
 337         }
 338
 339         /* Create a list of node names from those strings */
 340         char *node_inc[count];
 341
 342         debug("Hash nodes (%d):\n", count);
 343         for (name = prop, i = 0; name < end; name += strlen(name) + 1, i++) {
 344                 debug("   '%s'\n", name);
 345                 node_inc[i] = (char *)name;
 346         }
 347
 348         /*
 349          * Each node can generate one region for each sub-node. Allow for
 350          * 7 sub-nodes (hash@1, signature@1, etc.) and some extra.
 351          */
 352         max_regions = 20 + count * 7;
 353         struct fdt_region fdt_regions[max_regions];
 354
 355         /* Get a list of regions to hash */
 356         count = fdt_find_regions(fit, node_inc, count,
 357                         exc_prop, ARRAY_SIZE(exc_prop),
 358                         fdt_regions, max_regions - 1,
 359                         path, sizeof(path), 0);
 360         if (count < 0) {
 361                 *err_msgp = "Failed to hash configuration";
 362                 return -1;
 363         }
 364         if (count == 0) {
 365                 *err_msgp = "No data to hash";
 366                 return -1;
 367         }
 368         if (count >= max_regions - 1) {
 369                 *err_msgp = "Too many hash regions";
 370                 return -1;
 371         }
 372
 373         /* Add the strings */
 374         strings = fdt_getprop(fit, noffset, "hashed-strings", NULL);
 375         if (strings) {
 376                 fdt_regions[count].offset = fdt_off_dt_strings(fit) +
 377                                 fdt32_to_cpu(strings[0]);
 378                 fdt_regions[count].size = fdt32_to_cpu(strings[1]);
 379                 count++;
 380         }
 381
 382         /* Allocate the region list on the stack */
 383         struct image_region region[count];
 384
 385         fit_region_make_list(fit, fdt_regions, count, region);
 386         if (info.crypto->verify(&info, region, count, fit_value,
 387                                 fit_value_len)) {
 388                 *err_msgp = "Verification failed";
 389                 return -1;
 390         }
 391
 392         return 0;
 393 }
 394
 395 static int fit_config_verify_sig(const void *fit, int conf_noffset,
 396                 const void *sig_blob, int sig_offset)
 397 {
 398         int noffset;
 399         char *err_msg = "";
 400         int verified = 0;
 401         int ret;
 402
 403         /* Process all hash subnodes of the component conf node */
 404         fdt_for_each_subnode(noffset, fit, conf_noffset) {
 405                 const char *name = fit_get_name(fit, noffset, NULL);
 406
 407                 if (!strncmp(name, FIT_SIG_NODENAME,
 408                              strlen(FIT_SIG_NODENAME))) {
 409                         ret = fit_config_check_sig(fit, noffset, sig_offset,
 410                                                    &err_msg);
 411                         if (ret) {
 412                                 puts("- ");
 413                         } else {
 414                                 puts("+ ");
 415                                 verified = 1;
 416                                 break;
 417                         }
 418                 }
 419         }
 420
 421         if (noffset == -FDT_ERR_TRUNCATED || noffset == -FDT_ERR_BADSTRUCTURE) {
 422                 err_msg = "Corrupted or truncated tree";
 423                 goto error;
 424         }
 425
 426         return verified ? 0 : -EPERM;
 427
 428 error:
 429         printf(" error!\n%s for '%s' hash node in '%s' config node\n",
 430                err_msg, fit_get_name(fit, noffset, NULL),
 431                fit_get_name(fit, conf_noffset, NULL));
 432         return -1;
 433 }
 434
 435 int fit_config_verify_required_sigs(const void *fit, int conf_noffset,
 436                 const void *sig_blob)
 437 {
 438         int noffset;
 439         int sig_node;
 440
 441         /* Work out what we need to verify */
 442         sig_node = fdt_subnode_offset(sig_blob, 0, FIT_SIG_NODENAME);
 443         if (sig_node < 0) {
 444                 debug("%s: No signature node found: %s\n", __func__,
 445                       fdt_strerror(sig_node));
 446                 return 0;
 447         }
 448
 449         fdt_for_each_subnode(noffset, sig_blob, sig_node) {
 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 }