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