Juan Castillo | 05799ae | 2015-04-02 09:48:16 +0100 | [diff] [blame] | 1 | /* |
Ambroise Vincent | bde2836 | 2019-02-14 09:48:21 +0000 | [diff] [blame] | 2 | * Copyright (c) 2015-2019, ARM Limited and Contributors. All rights reserved. |
Juan Castillo | 05799ae | 2015-04-02 09:48:16 +0100 | [diff] [blame] | 3 | * |
dp-arm | 82cb2c1 | 2017-05-03 09:38:09 +0100 | [diff] [blame] | 4 | * SPDX-License-Identifier: BSD-3-Clause |
Juan Castillo | 05799ae | 2015-04-02 09:48:16 +0100 | [diff] [blame] | 5 | */ |
| 6 | |
| 7 | #include <assert.h> |
Juan Castillo | 05799ae | 2015-04-02 09:48:16 +0100 | [diff] [blame] | 8 | #include <stdint.h> |
| 9 | #include <string.h> |
| 10 | |
Antonio Nino Diaz | 09d40e0 | 2018-12-14 00:18:21 +0000 | [diff] [blame] | 11 | #include <platform_def.h> |
| 12 | |
| 13 | #include <common/debug.h> |
| 14 | #include <common/tbbr/cot_def.h> |
| 15 | #include <drivers/auth/auth_common.h> |
| 16 | #include <drivers/auth/auth_mod.h> |
| 17 | #include <drivers/auth/crypto_mod.h> |
| 18 | #include <drivers/auth/img_parser_mod.h> |
| 19 | #include <plat/common/platform.h> |
| 20 | |
Juan Castillo | 48279d5 | 2016-01-22 11:05:57 +0000 | [diff] [blame] | 21 | /* ASN.1 tags */ |
| 22 | #define ASN1_INTEGER 0x02 |
| 23 | |
Juan Castillo | 05799ae | 2015-04-02 09:48:16 +0100 | [diff] [blame] | 24 | #define return_if_error(rc) \ |
| 25 | do { \ |
| 26 | if (rc != 0) { \ |
| 27 | return rc; \ |
| 28 | } \ |
| 29 | } while (0) |
| 30 | |
dp-arm | d35dee2 | 2016-12-12 14:48:13 +0000 | [diff] [blame] | 31 | #pragma weak plat_set_nv_ctr2 |
| 32 | |
Joel Hutton | 0b6377d | 2019-02-20 11:56:46 +0000 | [diff] [blame] | 33 | /* Pointer to CoT */ |
| 34 | extern const auth_img_desc_t **const cot_desc_ptr; |
| 35 | extern unsigned int auth_img_flags[MAX_NUMBER_IDS]; |
| 36 | |
Juan Castillo | 05799ae | 2015-04-02 09:48:16 +0100 | [diff] [blame] | 37 | static int cmp_auth_param_type_desc(const auth_param_type_desc_t *a, |
| 38 | const auth_param_type_desc_t *b) |
| 39 | { |
| 40 | if ((a->type == b->type) && (a->cookie == b->cookie)) { |
| 41 | return 0; |
| 42 | } |
| 43 | return 1; |
| 44 | } |
| 45 | |
| 46 | /* |
| 47 | * This function obtains the requested authentication parameter data from the |
| 48 | * information extracted from the parent image after its authentication. |
| 49 | */ |
| 50 | static int auth_get_param(const auth_param_type_desc_t *param_type_desc, |
| 51 | const auth_img_desc_t *img_desc, |
| 52 | void **param, unsigned int *len) |
| 53 | { |
| 54 | int i; |
| 55 | |
Joel Hutton | 3007042 | 2019-03-11 11:37:38 +0000 | [diff] [blame] | 56 | if (img_desc->authenticated_data == NULL) |
| 57 | return 1; |
| 58 | |
Juan Castillo | 05799ae | 2015-04-02 09:48:16 +0100 | [diff] [blame] | 59 | for (i = 0 ; i < COT_MAX_VERIFIED_PARAMS ; i++) { |
| 60 | if (0 == cmp_auth_param_type_desc(param_type_desc, |
| 61 | img_desc->authenticated_data[i].type_desc)) { |
| 62 | *param = img_desc->authenticated_data[i].data.ptr; |
| 63 | *len = img_desc->authenticated_data[i].data.len; |
| 64 | return 0; |
| 65 | } |
| 66 | } |
| 67 | |
| 68 | return 1; |
| 69 | } |
| 70 | |
| 71 | /* |
| 72 | * Authenticate an image by matching the data hash |
| 73 | * |
| 74 | * This function implements 'AUTH_METHOD_HASH'. To authenticate an image using |
| 75 | * this method, the image must contain: |
| 76 | * |
| 77 | * - The data to calculate the hash from |
| 78 | * |
| 79 | * The parent image must contain: |
| 80 | * |
| 81 | * - The hash to be matched with (including hash algorithm) |
| 82 | * |
| 83 | * For a successful authentication, both hashes must match. The function calls |
| 84 | * the crypto-module to check this matching. |
| 85 | * |
| 86 | * Parameters: |
| 87 | * param: parameters to perform the hash authentication |
| 88 | * img_desc: pointer to image descriptor so we can know the image type |
| 89 | * and parent image |
| 90 | * img: pointer to image in memory |
| 91 | * img_len: length of image (in bytes) |
| 92 | * |
| 93 | * Return: |
| 94 | * 0 = success, Otherwise = error |
| 95 | */ |
| 96 | static int auth_hash(const auth_method_param_hash_t *param, |
| 97 | const auth_img_desc_t *img_desc, |
| 98 | void *img, unsigned int img_len) |
| 99 | { |
| 100 | void *data_ptr, *hash_der_ptr; |
| 101 | unsigned int data_len, hash_der_len; |
| 102 | int rc = 0; |
| 103 | |
| 104 | /* Get the hash from the parent image. This hash will be DER encoded |
| 105 | * and contain the hash algorithm */ |
| 106 | rc = auth_get_param(param->hash, img_desc->parent, |
| 107 | &hash_der_ptr, &hash_der_len); |
| 108 | return_if_error(rc); |
| 109 | |
| 110 | /* Get the data to be hashed from the current image */ |
| 111 | rc = img_parser_get_auth_param(img_desc->img_type, param->data, |
| 112 | img, img_len, &data_ptr, &data_len); |
| 113 | return_if_error(rc); |
| 114 | |
| 115 | /* Ask the crypto module to verify this hash */ |
| 116 | rc = crypto_mod_verify_hash(data_ptr, data_len, |
| 117 | hash_der_ptr, hash_der_len); |
| 118 | |
| 119 | return rc; |
| 120 | } |
| 121 | |
| 122 | /* |
| 123 | * Authenticate by digital signature |
| 124 | * |
| 125 | * This function implements 'AUTH_METHOD_SIG'. To authenticate an image using |
| 126 | * this method, the image must contain: |
| 127 | * |
| 128 | * - Data to be signed |
| 129 | * - Signature |
| 130 | * - Signature algorithm |
| 131 | * |
| 132 | * We rely on the image parser module to extract this data from the image. |
| 133 | * The parent image must contain: |
| 134 | * |
| 135 | * - Public key (or a hash of it) |
| 136 | * |
| 137 | * If the parent image contains only a hash of the key, we will try to obtain |
| 138 | * the public key from the image itself (i.e. self-signed certificates). In that |
| 139 | * case, the signature verification is considered just an integrity check and |
| 140 | * the authentication is established by calculating the hash of the key and |
| 141 | * comparing it with the hash obtained from the parent. |
| 142 | * |
| 143 | * If the image has no parent (NULL), it means it has to be authenticated using |
| 144 | * the ROTPK stored in the platform. Again, this ROTPK could be the key itself |
| 145 | * or a hash of it. |
| 146 | * |
| 147 | * Return: 0 = success, Otherwise = error |
| 148 | */ |
| 149 | static int auth_signature(const auth_method_param_sig_t *param, |
| 150 | const auth_img_desc_t *img_desc, |
| 151 | void *img, unsigned int img_len) |
| 152 | { |
| 153 | void *data_ptr, *pk_ptr, *pk_hash_ptr, *sig_ptr, *sig_alg_ptr; |
| 154 | unsigned int data_len, pk_len, pk_hash_len, sig_len, sig_alg_len; |
| 155 | unsigned int flags = 0; |
| 156 | int rc = 0; |
| 157 | |
| 158 | /* Get the data to be signed from current image */ |
| 159 | rc = img_parser_get_auth_param(img_desc->img_type, param->data, |
| 160 | img, img_len, &data_ptr, &data_len); |
| 161 | return_if_error(rc); |
| 162 | |
| 163 | /* Get the signature from current image */ |
| 164 | rc = img_parser_get_auth_param(img_desc->img_type, param->sig, |
| 165 | img, img_len, &sig_ptr, &sig_len); |
| 166 | return_if_error(rc); |
| 167 | |
| 168 | /* Get the signature algorithm from current image */ |
| 169 | rc = img_parser_get_auth_param(img_desc->img_type, param->alg, |
| 170 | img, img_len, &sig_alg_ptr, &sig_alg_len); |
| 171 | return_if_error(rc); |
| 172 | |
| 173 | /* Get the public key from the parent. If there is no parent (NULL), |
| 174 | * the certificate has been signed with the ROTPK, so we have to get |
| 175 | * the PK from the platform */ |
| 176 | if (img_desc->parent) { |
| 177 | rc = auth_get_param(param->pk, img_desc->parent, |
| 178 | &pk_ptr, &pk_len); |
| 179 | } else { |
| 180 | rc = plat_get_rotpk_info(param->pk->cookie, &pk_ptr, &pk_len, |
| 181 | &flags); |
| 182 | } |
| 183 | return_if_error(rc); |
| 184 | |
Soby Mathew | 04943d3 | 2016-05-24 15:05:15 +0100 | [diff] [blame] | 185 | if (flags & (ROTPK_IS_HASH | ROTPK_NOT_DEPLOYED)) { |
| 186 | /* If the PK is a hash of the key or if the ROTPK is not |
| 187 | deployed on the platform, retrieve the key from the image */ |
Juan Castillo | 05799ae | 2015-04-02 09:48:16 +0100 | [diff] [blame] | 188 | pk_hash_ptr = pk_ptr; |
| 189 | pk_hash_len = pk_len; |
| 190 | rc = img_parser_get_auth_param(img_desc->img_type, |
| 191 | param->pk, img, img_len, |
| 192 | &pk_ptr, &pk_len); |
| 193 | return_if_error(rc); |
| 194 | |
| 195 | /* Ask the crypto module to verify the signature */ |
| 196 | rc = crypto_mod_verify_signature(data_ptr, data_len, |
| 197 | sig_ptr, sig_len, |
| 198 | sig_alg_ptr, sig_alg_len, |
| 199 | pk_ptr, pk_len); |
| 200 | return_if_error(rc); |
| 201 | |
Soby Mathew | 04943d3 | 2016-05-24 15:05:15 +0100 | [diff] [blame] | 202 | if (flags & ROTPK_NOT_DEPLOYED) { |
| 203 | NOTICE("ROTPK is not deployed on platform. " |
| 204 | "Skipping ROTPK verification.\n"); |
| 205 | } else { |
| 206 | /* Ask the crypto-module to verify the key hash */ |
| 207 | rc = crypto_mod_verify_hash(pk_ptr, pk_len, |
| 208 | pk_hash_ptr, pk_hash_len); |
| 209 | } |
Juan Castillo | 05799ae | 2015-04-02 09:48:16 +0100 | [diff] [blame] | 210 | } else { |
| 211 | /* Ask the crypto module to verify the signature */ |
| 212 | rc = crypto_mod_verify_signature(data_ptr, data_len, |
| 213 | sig_ptr, sig_len, |
| 214 | sig_alg_ptr, sig_alg_len, |
| 215 | pk_ptr, pk_len); |
| 216 | } |
| 217 | |
| 218 | return rc; |
| 219 | } |
| 220 | |
| 221 | /* |
Juan Castillo | 48279d5 | 2016-01-22 11:05:57 +0000 | [diff] [blame] | 222 | * Authenticate by Non-Volatile counter |
| 223 | * |
| 224 | * To protect the system against rollback, the platform includes a non-volatile |
| 225 | * counter whose value can only be increased. All certificates include a counter |
| 226 | * value that should not be lower than the value stored in the platform. If the |
| 227 | * value is larger, the counter in the platform must be updated to the new |
| 228 | * value. |
| 229 | * |
| 230 | * Return: 0 = success, Otherwise = error |
| 231 | */ |
| 232 | static int auth_nvctr(const auth_method_param_nv_ctr_t *param, |
| 233 | const auth_img_desc_t *img_desc, |
| 234 | void *img, unsigned int img_len) |
| 235 | { |
| 236 | char *p; |
| 237 | void *data_ptr = NULL; |
| 238 | unsigned int data_len, len, i; |
| 239 | unsigned int cert_nv_ctr, plat_nv_ctr; |
| 240 | int rc = 0; |
| 241 | |
| 242 | /* Get the counter value from current image. The AM expects the IPM |
| 243 | * to return the counter value as a DER encoded integer */ |
| 244 | rc = img_parser_get_auth_param(img_desc->img_type, param->cert_nv_ctr, |
| 245 | img, img_len, &data_ptr, &data_len); |
| 246 | return_if_error(rc); |
| 247 | |
| 248 | /* Parse the DER encoded integer */ |
| 249 | assert(data_ptr); |
| 250 | p = (char *)data_ptr; |
| 251 | if (*p != ASN1_INTEGER) { |
| 252 | /* Invalid ASN.1 integer */ |
| 253 | return 1; |
| 254 | } |
| 255 | p++; |
| 256 | |
| 257 | /* NV-counters are unsigned integers up to 32-bit */ |
| 258 | len = (unsigned int)(*p & 0x7f); |
| 259 | if ((*p & 0x80) || (len > 4)) { |
| 260 | return 1; |
| 261 | } |
| 262 | p++; |
| 263 | |
| 264 | /* Check the number is not negative */ |
| 265 | if (*p & 0x80) { |
| 266 | return 1; |
| 267 | } |
| 268 | |
| 269 | /* Convert to unsigned int. This code is for a little-endian CPU */ |
| 270 | cert_nv_ctr = 0; |
| 271 | for (i = 0; i < len; i++) { |
| 272 | cert_nv_ctr = (cert_nv_ctr << 8) | *p++; |
| 273 | } |
| 274 | |
| 275 | /* Get the counter from the platform */ |
| 276 | rc = plat_get_nv_ctr(param->plat_nv_ctr->cookie, &plat_nv_ctr); |
| 277 | return_if_error(rc); |
| 278 | |
| 279 | if (cert_nv_ctr < plat_nv_ctr) { |
| 280 | /* Invalid NV-counter */ |
| 281 | return 1; |
| 282 | } else if (cert_nv_ctr > plat_nv_ctr) { |
dp-arm | d35dee2 | 2016-12-12 14:48:13 +0000 | [diff] [blame] | 283 | rc = plat_set_nv_ctr2(param->plat_nv_ctr->cookie, |
| 284 | img_desc, cert_nv_ctr); |
| 285 | return_if_error(rc); |
Juan Castillo | 48279d5 | 2016-01-22 11:05:57 +0000 | [diff] [blame] | 286 | } |
| 287 | |
| 288 | return 0; |
| 289 | } |
| 290 | |
dp-arm | d35dee2 | 2016-12-12 14:48:13 +0000 | [diff] [blame] | 291 | int plat_set_nv_ctr2(void *cookie, const auth_img_desc_t *img_desc __unused, |
| 292 | unsigned int nv_ctr) |
| 293 | { |
| 294 | return plat_set_nv_ctr(cookie, nv_ctr); |
| 295 | } |
| 296 | |
Juan Castillo | 48279d5 | 2016-01-22 11:05:57 +0000 | [diff] [blame] | 297 | /* |
Juan Castillo | 05799ae | 2015-04-02 09:48:16 +0100 | [diff] [blame] | 298 | * Return the parent id in the output parameter '*parent_id' |
| 299 | * |
| 300 | * Return value: |
| 301 | * 0 = Image has parent, 1 = Image has no parent or parent is authenticated |
| 302 | */ |
| 303 | int auth_mod_get_parent_id(unsigned int img_id, unsigned int *parent_id) |
| 304 | { |
| 305 | const auth_img_desc_t *img_desc = NULL; |
| 306 | |
| 307 | assert(parent_id != NULL); |
| 308 | |
| 309 | /* Get the image descriptor */ |
Joel Hutton | 0b6377d | 2019-02-20 11:56:46 +0000 | [diff] [blame] | 310 | img_desc = cot_desc_ptr[img_id]; |
Juan Castillo | 05799ae | 2015-04-02 09:48:16 +0100 | [diff] [blame] | 311 | |
| 312 | /* Check if the image has no parent (ROT) */ |
| 313 | if (img_desc->parent == NULL) { |
| 314 | *parent_id = 0; |
| 315 | return 1; |
| 316 | } |
| 317 | |
| 318 | /* Check if the parent has already been authenticated */ |
| 319 | if (auth_img_flags[img_desc->parent->img_id] & IMG_FLAG_AUTHENTICATED) { |
| 320 | *parent_id = 0; |
| 321 | return 1; |
| 322 | } |
| 323 | |
| 324 | *parent_id = img_desc->parent->img_id; |
| 325 | return 0; |
| 326 | } |
| 327 | |
| 328 | /* |
| 329 | * Initialize the different modules in the authentication framework |
| 330 | */ |
| 331 | void auth_mod_init(void) |
| 332 | { |
| 333 | /* Check we have a valid CoT registered */ |
| 334 | assert(cot_desc_ptr != NULL); |
| 335 | |
| 336 | /* Crypto module */ |
| 337 | crypto_mod_init(); |
| 338 | |
| 339 | /* Image parser module */ |
| 340 | img_parser_init(); |
| 341 | } |
| 342 | |
| 343 | /* |
| 344 | * Authenticate a certificate/image |
| 345 | * |
| 346 | * Return: 0 = success, Otherwise = error |
| 347 | */ |
| 348 | int auth_mod_verify_img(unsigned int img_id, |
| 349 | void *img_ptr, |
| 350 | unsigned int img_len) |
| 351 | { |
| 352 | const auth_img_desc_t *img_desc = NULL; |
| 353 | const auth_method_desc_t *auth_method = NULL; |
| 354 | void *param_ptr; |
| 355 | unsigned int param_len; |
| 356 | int rc, i; |
| 357 | |
| 358 | /* Get the image descriptor from the chain of trust */ |
Joel Hutton | 0b6377d | 2019-02-20 11:56:46 +0000 | [diff] [blame] | 359 | img_desc = cot_desc_ptr[img_id]; |
Juan Castillo | 05799ae | 2015-04-02 09:48:16 +0100 | [diff] [blame] | 360 | |
| 361 | /* Ask the parser to check the image integrity */ |
| 362 | rc = img_parser_check_integrity(img_desc->img_type, img_ptr, img_len); |
| 363 | return_if_error(rc); |
| 364 | |
| 365 | /* Authenticate the image using the methods indicated in the image |
| 366 | * descriptor. */ |
Joel Hutton | 7a246d6 | 2019-04-09 09:25:55 +0100 | [diff] [blame] | 367 | if (img_desc->img_auth_methods == NULL) |
Joel Hutton | 3007042 | 2019-03-11 11:37:38 +0000 | [diff] [blame] | 368 | return 1; |
Juan Castillo | 05799ae | 2015-04-02 09:48:16 +0100 | [diff] [blame] | 369 | for (i = 0 ; i < AUTH_METHOD_NUM ; i++) { |
| 370 | auth_method = &img_desc->img_auth_methods[i]; |
| 371 | switch (auth_method->type) { |
| 372 | case AUTH_METHOD_NONE: |
| 373 | rc = 0; |
| 374 | break; |
| 375 | case AUTH_METHOD_HASH: |
| 376 | rc = auth_hash(&auth_method->param.hash, |
| 377 | img_desc, img_ptr, img_len); |
| 378 | break; |
| 379 | case AUTH_METHOD_SIG: |
| 380 | rc = auth_signature(&auth_method->param.sig, |
| 381 | img_desc, img_ptr, img_len); |
| 382 | break; |
Juan Castillo | 48279d5 | 2016-01-22 11:05:57 +0000 | [diff] [blame] | 383 | case AUTH_METHOD_NV_CTR: |
| 384 | rc = auth_nvctr(&auth_method->param.nv_ctr, |
| 385 | img_desc, img_ptr, img_len); |
| 386 | break; |
Juan Castillo | 05799ae | 2015-04-02 09:48:16 +0100 | [diff] [blame] | 387 | default: |
| 388 | /* Unknown authentication method */ |
| 389 | rc = 1; |
| 390 | break; |
| 391 | } |
| 392 | return_if_error(rc); |
| 393 | } |
| 394 | |
| 395 | /* Extract the parameters indicated in the image descriptor to |
| 396 | * authenticate the children images. */ |
Joel Hutton | 3007042 | 2019-03-11 11:37:38 +0000 | [diff] [blame] | 397 | if (img_desc->authenticated_data != NULL) { |
| 398 | for (i = 0 ; i < COT_MAX_VERIFIED_PARAMS ; i++) { |
| 399 | if (img_desc->authenticated_data[i].type_desc == NULL) { |
| 400 | continue; |
| 401 | } |
| 402 | |
| 403 | /* Get the parameter from the image parser module */ |
| 404 | rc = img_parser_get_auth_param(img_desc->img_type, |
| 405 | img_desc->authenticated_data[i].type_desc, |
| 406 | img_ptr, img_len, ¶m_ptr, ¶m_len); |
| 407 | return_if_error(rc); |
| 408 | |
| 409 | /* Check parameter size */ |
| 410 | if (param_len > img_desc->authenticated_data[i].data.len) { |
| 411 | return 1; |
| 412 | } |
| 413 | |
| 414 | /* Copy the parameter for later use */ |
| 415 | memcpy((void *)img_desc->authenticated_data[i].data.ptr, |
| 416 | (void *)param_ptr, param_len); |
Juan Castillo | 05799ae | 2015-04-02 09:48:16 +0100 | [diff] [blame] | 417 | } |
Juan Castillo | 05799ae | 2015-04-02 09:48:16 +0100 | [diff] [blame] | 418 | } |
| 419 | |
| 420 | /* Mark image as authenticated */ |
| 421 | auth_img_flags[img_desc->img_id] |= IMG_FLAG_AUTHENTICATED; |
| 422 | |
| 423 | return 0; |
| 424 | } |