1 /*
2 * PSA ECP layer on top of Mbed TLS crypto
3 */
4 /*
5 * Copyright The Mbed TLS Contributors
6 * SPDX-License-Identifier: Apache-2.0 OR GPL-2.0-or-later
7 */
8
9 #include "common.h"
10
11 #if defined(MBEDTLS_PSA_CRYPTO_C) || defined(MCUBOOT_USE_PSA_CRYPTO)
12
13 #include <psa/crypto.h>
14 #include "psa_crypto_core.h"
15 #include "psa_crypto_ecp.h"
16 #include "psa_crypto_random_impl.h"
17 #include "mbedtls/psa_util.h"
18
19 #include <stdlib.h>
20 #include <string.h>
21 #include "mbedtls/platform.h"
22
23 #include <mbedtls/ecdsa.h>
24 #include <mbedtls/ecdh.h>
25 #include <mbedtls/ecp.h>
26 #include <mbedtls/error.h>
27
28 #if defined(MBEDTLS_PSA_BUILTIN_KEY_TYPE_ECC_KEY_PAIR_BASIC) || \
29 defined(MBEDTLS_PSA_BUILTIN_KEY_TYPE_ECC_KEY_PAIR_IMPORT) || \
30 defined(MBEDTLS_PSA_BUILTIN_KEY_TYPE_ECC_KEY_PAIR_EXPORT) || \
31 defined(MBEDTLS_PSA_BUILTIN_KEY_TYPE_ECC_PUBLIC_KEY) || \
32 defined(MBEDTLS_PSA_BUILTIN_ALG_ECDSA) || \
33 defined(MBEDTLS_PSA_BUILTIN_ALG_DETERMINISTIC_ECDSA) || \
34 defined(MBEDTLS_PSA_BUILTIN_ALG_ECDH)
35 /* Helper function to verify if the provided EC's family and key bit size are valid.
36 *
37 * Note: "bits" parameter is used both as input and output and it might be updated
38 * in case provided input value is not multiple of 8 ("sloppy" bits).
39 */
check_ecc_parameters(psa_ecc_family_t family,size_t * bits)40 static int check_ecc_parameters(psa_ecc_family_t family, size_t *bits)
41 {
42 switch (family) {
43 case PSA_ECC_FAMILY_SECP_R1:
44 switch (*bits) {
45 case 192:
46 case 224:
47 case 256:
48 case 384:
49 case 521:
50 return PSA_SUCCESS;
51 case 528:
52 *bits = 521;
53 return PSA_SUCCESS;
54 }
55 break;
56
57 case PSA_ECC_FAMILY_BRAINPOOL_P_R1:
58 switch (*bits) {
59 case 256:
60 case 384:
61 case 512:
62 return PSA_SUCCESS;
63 }
64 break;
65
66 case PSA_ECC_FAMILY_MONTGOMERY:
67 switch (*bits) {
68 case 448:
69 case 255:
70 return PSA_SUCCESS;
71 case 256:
72 *bits = 255;
73 return PSA_SUCCESS;
74 }
75 break;
76
77 case PSA_ECC_FAMILY_SECP_K1:
78 switch (*bits) {
79 case 192:
80 /* secp224k1 is not and will not be supported in PSA (#3541). */
81 case 256:
82 return PSA_SUCCESS;
83 }
84 break;
85 }
86
87 return PSA_ERROR_INVALID_ARGUMENT;
88 }
89
mbedtls_psa_ecp_load_representation(psa_key_type_t type,size_t curve_bits,const uint8_t * data,size_t data_length,mbedtls_ecp_keypair ** p_ecp)90 psa_status_t mbedtls_psa_ecp_load_representation(
91 psa_key_type_t type, size_t curve_bits,
92 const uint8_t *data, size_t data_length,
93 mbedtls_ecp_keypair **p_ecp)
94 {
95 mbedtls_ecp_group_id grp_id = MBEDTLS_ECP_DP_NONE;
96 psa_status_t status;
97 mbedtls_ecp_keypair *ecp = NULL;
98 size_t curve_bytes = data_length;
99 int explicit_bits = (curve_bits != 0);
100
101 if (PSA_KEY_TYPE_IS_PUBLIC_KEY(type) &&
102 PSA_KEY_TYPE_ECC_GET_FAMILY(type) != PSA_ECC_FAMILY_MONTGOMERY) {
103 /* A Weierstrass public key is represented as:
104 * - The byte 0x04;
105 * - `x_P` as a `ceiling(m/8)`-byte string, big-endian;
106 * - `y_P` as a `ceiling(m/8)`-byte string, big-endian.
107 * So its data length is 2m+1 where m is the curve size in bits.
108 */
109 if ((data_length & 1) == 0) {
110 return PSA_ERROR_INVALID_ARGUMENT;
111 }
112 curve_bytes = data_length / 2;
113
114 /* Montgomery public keys are represented in compressed format, meaning
115 * their curve_bytes is equal to the amount of input. */
116
117 /* Private keys are represented in uncompressed private random integer
118 * format, meaning their curve_bytes is equal to the amount of input. */
119 }
120
121 if (explicit_bits) {
122 /* With an explicit bit-size, the data must have the matching length. */
123 if (curve_bytes != PSA_BITS_TO_BYTES(curve_bits)) {
124 return PSA_ERROR_INVALID_ARGUMENT;
125 }
126 } else {
127 /* We need to infer the bit-size from the data. Since the only
128 * information we have is the length in bytes, the value of curve_bits
129 * at this stage is rounded up to the nearest multiple of 8. */
130 curve_bits = PSA_BYTES_TO_BITS(curve_bytes);
131 }
132
133 /* Allocate and initialize a key representation. */
134 ecp = mbedtls_calloc(1, sizeof(mbedtls_ecp_keypair));
135 if (ecp == NULL) {
136 return PSA_ERROR_INSUFFICIENT_MEMORY;
137 }
138 mbedtls_ecp_keypair_init(ecp);
139
140 status = check_ecc_parameters(PSA_KEY_TYPE_ECC_GET_FAMILY(type), &curve_bits);
141 if (status != PSA_SUCCESS) {
142 goto exit;
143 }
144
145 /* Load the group. */
146 grp_id = mbedtls_ecc_group_from_psa(PSA_KEY_TYPE_ECC_GET_FAMILY(type),
147 curve_bits);
148 if (grp_id == MBEDTLS_ECP_DP_NONE) {
149 status = PSA_ERROR_NOT_SUPPORTED;
150 goto exit;
151 }
152
153 status = mbedtls_to_psa_error(
154 mbedtls_ecp_group_load(&ecp->grp, grp_id));
155 if (status != PSA_SUCCESS) {
156 goto exit;
157 }
158
159 /* Load the key material. */
160 if (PSA_KEY_TYPE_IS_PUBLIC_KEY(type)) {
161 /* Load the public value. */
162 status = mbedtls_to_psa_error(
163 mbedtls_ecp_point_read_binary(&ecp->grp, &ecp->Q,
164 data,
165 data_length));
166 if (status != PSA_SUCCESS) {
167 goto exit;
168 }
169
170 /* Check that the point is on the curve. */
171 status = mbedtls_to_psa_error(
172 mbedtls_ecp_check_pubkey(&ecp->grp, &ecp->Q));
173 if (status != PSA_SUCCESS) {
174 goto exit;
175 }
176 } else {
177 /* Load and validate the secret value. */
178 status = mbedtls_to_psa_error(
179 mbedtls_ecp_read_key(ecp->grp.id,
180 ecp,
181 data,
182 data_length));
183 if (status != PSA_SUCCESS) {
184 goto exit;
185 }
186 }
187
188 *p_ecp = ecp;
189 exit:
190 if (status != PSA_SUCCESS) {
191 mbedtls_ecp_keypair_free(ecp);
192 mbedtls_free(ecp);
193 }
194
195 return status;
196 }
197 #endif /* defined(MBEDTLS_PSA_BUILTIN_KEY_TYPE_ECC_KEY_PAIR_BASIC) ||
198 * defined(MBEDTLS_PSA_BUILTIN_KEY_TYPE_ECC_KEY_PAIR_IMPORT) ||
199 * defined(MBEDTLS_PSA_BUILTIN_KEY_TYPE_ECC_KEY_PAIR_EXPORT) ||
200 * defined(MBEDTLS_PSA_BUILTIN_KEY_TYPE_ECC_PUBLIC_KEY) ||
201 * defined(MBEDTLS_PSA_BUILTIN_ALG_ECDSA) ||
202 * defined(MBEDTLS_PSA_BUILTIN_ALG_DETERMINISTIC_ECDSA) ||
203 * defined(MBEDTLS_PSA_BUILTIN_ALG_ECDH) */
204
205 #if defined(MBEDTLS_PSA_BUILTIN_KEY_TYPE_ECC_KEY_PAIR_IMPORT) || \
206 defined(MBEDTLS_PSA_BUILTIN_KEY_TYPE_ECC_KEY_PAIR_EXPORT) || \
207 defined(MBEDTLS_PSA_BUILTIN_KEY_TYPE_ECC_PUBLIC_KEY)
208
mbedtls_psa_ecp_import_key(const psa_key_attributes_t * attributes,const uint8_t * data,size_t data_length,uint8_t * key_buffer,size_t key_buffer_size,size_t * key_buffer_length,size_t * bits)209 psa_status_t mbedtls_psa_ecp_import_key(
210 const psa_key_attributes_t *attributes,
211 const uint8_t *data, size_t data_length,
212 uint8_t *key_buffer, size_t key_buffer_size,
213 size_t *key_buffer_length, size_t *bits)
214 {
215 psa_status_t status;
216 mbedtls_ecp_keypair *ecp = NULL;
217
218 /* Parse input */
219 status = mbedtls_psa_ecp_load_representation(attributes->type,
220 attributes->bits,
221 data,
222 data_length,
223 &ecp);
224 if (status != PSA_SUCCESS) {
225 goto exit;
226 }
227
228 if (PSA_KEY_TYPE_ECC_GET_FAMILY(attributes->type) ==
229 PSA_ECC_FAMILY_MONTGOMERY) {
230 *bits = ecp->grp.nbits + 1;
231 } else {
232 *bits = ecp->grp.nbits;
233 }
234
235 /* Re-export the data to PSA export format. There is currently no support
236 * for other input formats then the export format, so this is a 1-1
237 * copy operation. */
238 status = mbedtls_psa_ecp_export_key(attributes->type,
239 ecp,
240 key_buffer,
241 key_buffer_size,
242 key_buffer_length);
243 exit:
244 /* Always free the PK object (will also free contained ECP context) */
245 mbedtls_ecp_keypair_free(ecp);
246 mbedtls_free(ecp);
247
248 return status;
249 }
250
mbedtls_psa_ecp_export_key(psa_key_type_t type,mbedtls_ecp_keypair * ecp,uint8_t * data,size_t data_size,size_t * data_length)251 psa_status_t mbedtls_psa_ecp_export_key(psa_key_type_t type,
252 mbedtls_ecp_keypair *ecp,
253 uint8_t *data,
254 size_t data_size,
255 size_t *data_length)
256 {
257 psa_status_t status;
258
259 if (PSA_KEY_TYPE_IS_PUBLIC_KEY(type)) {
260 /* Check whether the public part is loaded */
261 if (mbedtls_ecp_is_zero(&ecp->Q)) {
262 /* Calculate the public key */
263 status = mbedtls_to_psa_error(
264 mbedtls_ecp_mul(&ecp->grp, &ecp->Q, &ecp->d, &ecp->grp.G,
265 mbedtls_psa_get_random,
266 MBEDTLS_PSA_RANDOM_STATE));
267 if (status != PSA_SUCCESS) {
268 return status;
269 }
270 }
271
272 status = mbedtls_to_psa_error(
273 mbedtls_ecp_point_write_binary(&ecp->grp, &ecp->Q,
274 MBEDTLS_ECP_PF_UNCOMPRESSED,
275 data_length,
276 data,
277 data_size));
278 if (status != PSA_SUCCESS) {
279 memset(data, 0, data_size);
280 }
281
282 return status;
283 } else {
284 status = mbedtls_to_psa_error(
285 mbedtls_ecp_write_key_ext(ecp, data_length, data, data_size));
286 return status;
287 }
288 }
289
mbedtls_psa_ecp_export_public_key(const psa_key_attributes_t * attributes,const uint8_t * key_buffer,size_t key_buffer_size,uint8_t * data,size_t data_size,size_t * data_length)290 psa_status_t mbedtls_psa_ecp_export_public_key(
291 const psa_key_attributes_t *attributes,
292 const uint8_t *key_buffer, size_t key_buffer_size,
293 uint8_t *data, size_t data_size, size_t *data_length)
294 {
295 psa_status_t status = PSA_ERROR_CORRUPTION_DETECTED;
296 mbedtls_ecp_keypair *ecp = NULL;
297
298 status = mbedtls_psa_ecp_load_representation(
299 attributes->type, attributes->bits,
300 key_buffer, key_buffer_size, &ecp);
301 if (status != PSA_SUCCESS) {
302 return status;
303 }
304
305 status = mbedtls_psa_ecp_export_key(
306 PSA_KEY_TYPE_ECC_PUBLIC_KEY(
307 PSA_KEY_TYPE_ECC_GET_FAMILY(attributes->type)),
308 ecp, data, data_size, data_length);
309
310 mbedtls_ecp_keypair_free(ecp);
311 mbedtls_free(ecp);
312
313 return status;
314 }
315 #endif /* defined(MBEDTLS_PSA_BUILTIN_KEY_TYPE_ECC_KEY_PAIR_IMPORT) ||
316 * defined(MBEDTLS_PSA_BUILTIN_KEY_TYPE_ECC_KEY_PAIR_EXPORT) ||
317 * defined(MBEDTLS_PSA_BUILTIN_KEY_TYPE_ECC_PUBLIC_KEY) */
318
319 #if defined(MBEDTLS_PSA_BUILTIN_KEY_TYPE_ECC_KEY_PAIR_GENERATE)
mbedtls_psa_ecp_generate_key(const psa_key_attributes_t * attributes,uint8_t * key_buffer,size_t key_buffer_size,size_t * key_buffer_length)320 psa_status_t mbedtls_psa_ecp_generate_key(
321 const psa_key_attributes_t *attributes,
322 uint8_t *key_buffer, size_t key_buffer_size, size_t *key_buffer_length)
323 {
324 psa_status_t status = PSA_ERROR_CORRUPTION_DETECTED;
325 int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
326
327 psa_ecc_family_t curve = PSA_KEY_TYPE_ECC_GET_FAMILY(
328 attributes->type);
329 mbedtls_ecp_group_id grp_id =
330 mbedtls_ecc_group_from_psa(curve, attributes->bits);
331
332 const mbedtls_ecp_curve_info *curve_info =
333 mbedtls_ecp_curve_info_from_grp_id(grp_id);
334 mbedtls_ecp_keypair ecp;
335
336 if (grp_id == MBEDTLS_ECP_DP_NONE || curve_info == NULL) {
337 return PSA_ERROR_NOT_SUPPORTED;
338 }
339
340 mbedtls_ecp_keypair_init(&ecp);
341 ret = mbedtls_ecp_gen_key(grp_id, &ecp,
342 mbedtls_psa_get_random,
343 MBEDTLS_PSA_RANDOM_STATE);
344 if (ret != 0) {
345 mbedtls_ecp_keypair_free(&ecp);
346 return mbedtls_to_psa_error(ret);
347 }
348
349 status = mbedtls_to_psa_error(
350 mbedtls_ecp_write_key_ext(&ecp, key_buffer_length,
351 key_buffer, key_buffer_size));
352
353 mbedtls_ecp_keypair_free(&ecp);
354
355 return status;
356 }
357 #endif /* MBEDTLS_PSA_BUILTIN_KEY_TYPE_ECC_KEY_PAIR_GENERATE */
358
359 /****************************************************************/
360 /* ECDSA sign/verify */
361 /****************************************************************/
362
363 #if defined(MBEDTLS_PSA_BUILTIN_ALG_ECDSA) || \
364 defined(MBEDTLS_PSA_BUILTIN_ALG_DETERMINISTIC_ECDSA)
mbedtls_psa_ecdsa_sign_hash(const psa_key_attributes_t * attributes,const uint8_t * key_buffer,size_t key_buffer_size,psa_algorithm_t alg,const uint8_t * hash,size_t hash_length,uint8_t * signature,size_t signature_size,size_t * signature_length)365 psa_status_t mbedtls_psa_ecdsa_sign_hash(
366 const psa_key_attributes_t *attributes,
367 const uint8_t *key_buffer, size_t key_buffer_size,
368 psa_algorithm_t alg, const uint8_t *hash, size_t hash_length,
369 uint8_t *signature, size_t signature_size, size_t *signature_length)
370 {
371 psa_status_t status = PSA_ERROR_CORRUPTION_DETECTED;
372 mbedtls_ecp_keypair *ecp = NULL;
373 int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
374 size_t curve_bytes;
375 mbedtls_mpi r, s;
376
377 status = mbedtls_psa_ecp_load_representation(attributes->type,
378 attributes->bits,
379 key_buffer,
380 key_buffer_size,
381 &ecp);
382 if (status != PSA_SUCCESS) {
383 return status;
384 }
385
386 curve_bytes = PSA_BITS_TO_BYTES(ecp->grp.pbits);
387 mbedtls_mpi_init(&r);
388 mbedtls_mpi_init(&s);
389
390 if (signature_size < 2 * curve_bytes) {
391 ret = MBEDTLS_ERR_ECP_BUFFER_TOO_SMALL;
392 goto cleanup;
393 }
394
395 if (PSA_ALG_ECDSA_IS_DETERMINISTIC(alg)) {
396 #if defined(MBEDTLS_PSA_BUILTIN_ALG_DETERMINISTIC_ECDSA)
397 psa_algorithm_t hash_alg = PSA_ALG_SIGN_GET_HASH(alg);
398 mbedtls_md_type_t md_alg = mbedtls_md_type_from_psa_alg(hash_alg);
399 MBEDTLS_MPI_CHK(mbedtls_ecdsa_sign_det_ext(
400 &ecp->grp, &r, &s,
401 &ecp->d, hash,
402 hash_length, md_alg,
403 mbedtls_psa_get_random,
404 MBEDTLS_PSA_RANDOM_STATE));
405 #else
406 ret = MBEDTLS_ERR_ECP_FEATURE_UNAVAILABLE;
407 goto cleanup;
408 #endif /* defined(MBEDTLS_PSA_BUILTIN_ALG_DETERMINISTIC_ECDSA) */
409 } else {
410 (void) alg;
411 MBEDTLS_MPI_CHK(mbedtls_ecdsa_sign(&ecp->grp, &r, &s, &ecp->d,
412 hash, hash_length,
413 mbedtls_psa_get_random,
414 MBEDTLS_PSA_RANDOM_STATE));
415 }
416
417 MBEDTLS_MPI_CHK(mbedtls_mpi_write_binary(&r,
418 signature,
419 curve_bytes));
420 MBEDTLS_MPI_CHK(mbedtls_mpi_write_binary(&s,
421 signature + curve_bytes,
422 curve_bytes));
423 cleanup:
424 mbedtls_mpi_free(&r);
425 mbedtls_mpi_free(&s);
426 if (ret == 0) {
427 *signature_length = 2 * curve_bytes;
428 }
429
430 mbedtls_ecp_keypair_free(ecp);
431 mbedtls_free(ecp);
432
433 return mbedtls_to_psa_error(ret);
434 }
435
mbedtls_psa_ecp_load_public_part(mbedtls_ecp_keypair * ecp)436 psa_status_t mbedtls_psa_ecp_load_public_part(mbedtls_ecp_keypair *ecp)
437 {
438 int ret = 0;
439
440 /* Check whether the public part is loaded. If not, load it. */
441 if (mbedtls_ecp_is_zero(&ecp->Q)) {
442 ret = mbedtls_ecp_mul(&ecp->grp, &ecp->Q,
443 &ecp->d, &ecp->grp.G,
444 mbedtls_psa_get_random,
445 MBEDTLS_PSA_RANDOM_STATE);
446 }
447
448 return mbedtls_to_psa_error(ret);
449 }
450
mbedtls_psa_ecdsa_verify_hash(const psa_key_attributes_t * attributes,const uint8_t * key_buffer,size_t key_buffer_size,psa_algorithm_t alg,const uint8_t * hash,size_t hash_length,const uint8_t * signature,size_t signature_length)451 psa_status_t mbedtls_psa_ecdsa_verify_hash(
452 const psa_key_attributes_t *attributes,
453 const uint8_t *key_buffer, size_t key_buffer_size,
454 psa_algorithm_t alg, const uint8_t *hash, size_t hash_length,
455 const uint8_t *signature, size_t signature_length)
456 {
457 psa_status_t status = PSA_ERROR_CORRUPTION_DETECTED;
458 mbedtls_ecp_keypair *ecp = NULL;
459 size_t curve_bytes;
460 mbedtls_mpi r, s;
461
462 (void) alg;
463
464 status = mbedtls_psa_ecp_load_representation(attributes->type,
465 attributes->bits,
466 key_buffer,
467 key_buffer_size,
468 &ecp);
469 if (status != PSA_SUCCESS) {
470 return status;
471 }
472
473 curve_bytes = PSA_BITS_TO_BYTES(ecp->grp.pbits);
474 mbedtls_mpi_init(&r);
475 mbedtls_mpi_init(&s);
476
477 if (signature_length != 2 * curve_bytes) {
478 status = PSA_ERROR_INVALID_SIGNATURE;
479 goto cleanup;
480 }
481
482 status = mbedtls_to_psa_error(mbedtls_mpi_read_binary(&r,
483 signature,
484 curve_bytes));
485 if (status != PSA_SUCCESS) {
486 goto cleanup;
487 }
488
489 status = mbedtls_to_psa_error(mbedtls_mpi_read_binary(&s,
490 signature + curve_bytes,
491 curve_bytes));
492 if (status != PSA_SUCCESS) {
493 goto cleanup;
494 }
495
496 status = mbedtls_psa_ecp_load_public_part(ecp);
497 if (status != PSA_SUCCESS) {
498 goto cleanup;
499 }
500
501 status = mbedtls_to_psa_error(mbedtls_ecdsa_verify(&ecp->grp, hash,
502 hash_length, &ecp->Q,
503 &r, &s));
504 cleanup:
505 mbedtls_mpi_free(&r);
506 mbedtls_mpi_free(&s);
507 mbedtls_ecp_keypair_free(ecp);
508 mbedtls_free(ecp);
509
510 return status;
511 }
512
513 #endif /* defined(MBEDTLS_PSA_BUILTIN_ALG_ECDSA) || \
514 * defined(MBEDTLS_PSA_BUILTIN_ALG_DETERMINISTIC_ECDSA) */
515
516 /****************************************************************/
517 /* ECDH Key Agreement */
518 /****************************************************************/
519
520 #if defined(MBEDTLS_PSA_BUILTIN_ALG_ECDH)
mbedtls_psa_key_agreement_ecdh(const psa_key_attributes_t * attributes,const uint8_t * key_buffer,size_t key_buffer_size,psa_algorithm_t alg,const uint8_t * peer_key,size_t peer_key_length,uint8_t * shared_secret,size_t shared_secret_size,size_t * shared_secret_length)521 psa_status_t mbedtls_psa_key_agreement_ecdh(
522 const psa_key_attributes_t *attributes,
523 const uint8_t *key_buffer, size_t key_buffer_size,
524 psa_algorithm_t alg, const uint8_t *peer_key, size_t peer_key_length,
525 uint8_t *shared_secret, size_t shared_secret_size,
526 size_t *shared_secret_length)
527 {
528 psa_status_t status;
529 if (!PSA_KEY_TYPE_IS_ECC_KEY_PAIR(attributes->type) ||
530 !PSA_ALG_IS_ECDH(alg)) {
531 return PSA_ERROR_INVALID_ARGUMENT;
532 }
533 mbedtls_ecp_keypair *ecp = NULL;
534 status = mbedtls_psa_ecp_load_representation(
535 attributes->type,
536 attributes->bits,
537 key_buffer,
538 key_buffer_size,
539 &ecp);
540 if (status != PSA_SUCCESS) {
541 return status;
542 }
543 mbedtls_ecp_keypair *their_key = NULL;
544 mbedtls_ecdh_context ecdh;
545 size_t bits = 0;
546 psa_ecc_family_t curve = mbedtls_ecc_group_to_psa(ecp->grp.id, &bits);
547 mbedtls_ecdh_init(&ecdh);
548
549 status = mbedtls_psa_ecp_load_representation(
550 PSA_KEY_TYPE_ECC_PUBLIC_KEY(curve),
551 bits,
552 peer_key,
553 peer_key_length,
554 &their_key);
555 if (status != PSA_SUCCESS) {
556 goto exit;
557 }
558
559 status = mbedtls_to_psa_error(
560 mbedtls_ecdh_get_params(&ecdh, their_key, MBEDTLS_ECDH_THEIRS));
561 if (status != PSA_SUCCESS) {
562 goto exit;
563 }
564 status = mbedtls_to_psa_error(
565 mbedtls_ecdh_get_params(&ecdh, ecp, MBEDTLS_ECDH_OURS));
566 if (status != PSA_SUCCESS) {
567 goto exit;
568 }
569
570 status = mbedtls_to_psa_error(
571 mbedtls_ecdh_calc_secret(&ecdh,
572 shared_secret_length,
573 shared_secret, shared_secret_size,
574 mbedtls_psa_get_random,
575 MBEDTLS_PSA_RANDOM_STATE));
576 if (status != PSA_SUCCESS) {
577 goto exit;
578 }
579 if (PSA_BITS_TO_BYTES(bits) != *shared_secret_length) {
580 status = PSA_ERROR_CORRUPTION_DETECTED;
581 }
582 exit:
583 if (status != PSA_SUCCESS) {
584 mbedtls_platform_zeroize(shared_secret, shared_secret_size);
585 }
586 mbedtls_ecdh_free(&ecdh);
587 mbedtls_ecp_keypair_free(their_key);
588 mbedtls_free(their_key);
589 mbedtls_ecp_keypair_free(ecp);
590 mbedtls_free(ecp);
591 return status;
592 }
593 #endif /* MBEDTLS_PSA_BUILTIN_ALG_ECDH */
594
595
596 #endif /* MBEDTLS_PSA_CRYPTO_C */
597
