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)
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_ecc_family_t curve = PSA_KEY_TYPE_ECC_GET_FAMILY(
325 attributes->type);
326 mbedtls_ecp_group_id grp_id =
327 mbedtls_ecc_group_from_psa(curve, attributes->bits);
328 if (grp_id == MBEDTLS_ECP_DP_NONE) {
329 return PSA_ERROR_NOT_SUPPORTED;
330 }
331
332 mbedtls_ecp_keypair ecp;
333 mbedtls_ecp_keypair_init(&ecp);
334 int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
335
336 ret = mbedtls_ecp_group_load(&ecp.grp, grp_id);
337 if (ret != 0) {
338 goto exit;
339 }
340
341 ret = mbedtls_ecp_gen_privkey(&ecp.grp, &ecp.d,
342 mbedtls_psa_get_random,
343 MBEDTLS_PSA_RANDOM_STATE);
344 if (ret != 0) {
345 goto exit;
346 }
347
348 ret = mbedtls_ecp_write_key_ext(&ecp, key_buffer_length,
349 key_buffer, key_buffer_size);
350
351 exit:
352 mbedtls_ecp_keypair_free(&ecp);
353 return mbedtls_to_psa_error(ret);
354 }
355 #endif /* MBEDTLS_PSA_BUILTIN_KEY_TYPE_ECC_KEY_PAIR_GENERATE */
356
357 /****************************************************************/
358 /* ECDSA sign/verify */
359 /****************************************************************/
360
361 #if defined(MBEDTLS_PSA_BUILTIN_ALG_ECDSA) || \
362 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)363 psa_status_t mbedtls_psa_ecdsa_sign_hash(
364 const psa_key_attributes_t *attributes,
365 const uint8_t *key_buffer, size_t key_buffer_size,
366 psa_algorithm_t alg, const uint8_t *hash, size_t hash_length,
367 uint8_t *signature, size_t signature_size, size_t *signature_length)
368 {
369 psa_status_t status = PSA_ERROR_CORRUPTION_DETECTED;
370 mbedtls_ecp_keypair *ecp = NULL;
371 int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
372 size_t curve_bytes;
373 mbedtls_mpi r, s;
374
375 status = mbedtls_psa_ecp_load_representation(attributes->type,
376 attributes->bits,
377 key_buffer,
378 key_buffer_size,
379 &ecp);
380 if (status != PSA_SUCCESS) {
381 return status;
382 }
383
384 curve_bytes = PSA_BITS_TO_BYTES(ecp->grp.pbits);
385 mbedtls_mpi_init(&r);
386 mbedtls_mpi_init(&s);
387
388 if (signature_size < 2 * curve_bytes) {
389 ret = MBEDTLS_ERR_ECP_BUFFER_TOO_SMALL;
390 goto cleanup;
391 }
392
393 if (PSA_ALG_ECDSA_IS_DETERMINISTIC(alg)) {
394 #if defined(MBEDTLS_PSA_BUILTIN_ALG_DETERMINISTIC_ECDSA)
395 psa_algorithm_t hash_alg = PSA_ALG_SIGN_GET_HASH(alg);
396 mbedtls_md_type_t md_alg = mbedtls_md_type_from_psa_alg(hash_alg);
397 MBEDTLS_MPI_CHK(mbedtls_ecdsa_sign_det_ext(
398 &ecp->grp, &r, &s,
399 &ecp->d, hash,
400 hash_length, md_alg,
401 mbedtls_psa_get_random,
402 MBEDTLS_PSA_RANDOM_STATE));
403 #else
404 ret = MBEDTLS_ERR_ECP_FEATURE_UNAVAILABLE;
405 goto cleanup;
406 #endif /* defined(MBEDTLS_PSA_BUILTIN_ALG_DETERMINISTIC_ECDSA) */
407 } else {
408 (void) alg;
409 MBEDTLS_MPI_CHK(mbedtls_ecdsa_sign(&ecp->grp, &r, &s, &ecp->d,
410 hash, hash_length,
411 mbedtls_psa_get_random,
412 MBEDTLS_PSA_RANDOM_STATE));
413 }
414
415 MBEDTLS_MPI_CHK(mbedtls_mpi_write_binary(&r,
416 signature,
417 curve_bytes));
418 MBEDTLS_MPI_CHK(mbedtls_mpi_write_binary(&s,
419 signature + curve_bytes,
420 curve_bytes));
421 cleanup:
422 mbedtls_mpi_free(&r);
423 mbedtls_mpi_free(&s);
424 if (ret == 0) {
425 *signature_length = 2 * curve_bytes;
426 }
427
428 mbedtls_ecp_keypair_free(ecp);
429 mbedtls_free(ecp);
430
431 return mbedtls_to_psa_error(ret);
432 }
433
mbedtls_psa_ecp_load_public_part(mbedtls_ecp_keypair * ecp)434 psa_status_t mbedtls_psa_ecp_load_public_part(mbedtls_ecp_keypair *ecp)
435 {
436 int ret = 0;
437
438 /* Check whether the public part is loaded. If not, load it. */
439 if (mbedtls_ecp_is_zero(&ecp->Q)) {
440 ret = mbedtls_ecp_mul(&ecp->grp, &ecp->Q,
441 &ecp->d, &ecp->grp.G,
442 mbedtls_psa_get_random,
443 MBEDTLS_PSA_RANDOM_STATE);
444 }
445
446 return mbedtls_to_psa_error(ret);
447 }
448
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)449 psa_status_t mbedtls_psa_ecdsa_verify_hash(
450 const psa_key_attributes_t *attributes,
451 const uint8_t *key_buffer, size_t key_buffer_size,
452 psa_algorithm_t alg, const uint8_t *hash, size_t hash_length,
453 const uint8_t *signature, size_t signature_length)
454 {
455 psa_status_t status = PSA_ERROR_CORRUPTION_DETECTED;
456 mbedtls_ecp_keypair *ecp = NULL;
457 size_t curve_bytes;
458 mbedtls_mpi r, s;
459
460 (void) alg;
461
462 status = mbedtls_psa_ecp_load_representation(attributes->type,
463 attributes->bits,
464 key_buffer,
465 key_buffer_size,
466 &ecp);
467 if (status != PSA_SUCCESS) {
468 return status;
469 }
470
471 curve_bytes = PSA_BITS_TO_BYTES(ecp->grp.pbits);
472 mbedtls_mpi_init(&r);
473 mbedtls_mpi_init(&s);
474
475 if (signature_length != 2 * curve_bytes) {
476 status = PSA_ERROR_INVALID_SIGNATURE;
477 goto cleanup;
478 }
479
480 status = mbedtls_to_psa_error(mbedtls_mpi_read_binary(&r,
481 signature,
482 curve_bytes));
483 if (status != PSA_SUCCESS) {
484 goto cleanup;
485 }
486
487 status = mbedtls_to_psa_error(mbedtls_mpi_read_binary(&s,
488 signature + curve_bytes,
489 curve_bytes));
490 if (status != PSA_SUCCESS) {
491 goto cleanup;
492 }
493
494 status = mbedtls_psa_ecp_load_public_part(ecp);
495 if (status != PSA_SUCCESS) {
496 goto cleanup;
497 }
498
499 status = mbedtls_to_psa_error(mbedtls_ecdsa_verify(&ecp->grp, hash,
500 hash_length, &ecp->Q,
501 &r, &s));
502 cleanup:
503 mbedtls_mpi_free(&r);
504 mbedtls_mpi_free(&s);
505 mbedtls_ecp_keypair_free(ecp);
506 mbedtls_free(ecp);
507
508 return status;
509 }
510
511 #endif /* defined(MBEDTLS_PSA_BUILTIN_ALG_ECDSA) || \
512 * defined(MBEDTLS_PSA_BUILTIN_ALG_DETERMINISTIC_ECDSA) */
513
514 /****************************************************************/
515 /* ECDH Key Agreement */
516 /****************************************************************/
517
518 #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)519 psa_status_t mbedtls_psa_key_agreement_ecdh(
520 const psa_key_attributes_t *attributes,
521 const uint8_t *key_buffer, size_t key_buffer_size,
522 psa_algorithm_t alg, const uint8_t *peer_key, size_t peer_key_length,
523 uint8_t *shared_secret, size_t shared_secret_size,
524 size_t *shared_secret_length)
525 {
526 psa_status_t status;
527 if (!PSA_KEY_TYPE_IS_ECC_KEY_PAIR(attributes->type) ||
528 !PSA_ALG_IS_ECDH(alg)) {
529 return PSA_ERROR_INVALID_ARGUMENT;
530 }
531 mbedtls_ecp_keypair *ecp = NULL;
532 status = mbedtls_psa_ecp_load_representation(
533 attributes->type,
534 attributes->bits,
535 key_buffer,
536 key_buffer_size,
537 &ecp);
538 if (status != PSA_SUCCESS) {
539 return status;
540 }
541 mbedtls_ecp_keypair *their_key = NULL;
542 mbedtls_ecdh_context ecdh;
543 size_t bits = 0;
544 psa_ecc_family_t curve = mbedtls_ecc_group_to_psa(ecp->grp.id, &bits);
545 mbedtls_ecdh_init(&ecdh);
546
547 status = mbedtls_psa_ecp_load_representation(
548 PSA_KEY_TYPE_ECC_PUBLIC_KEY(curve),
549 bits,
550 peer_key,
551 peer_key_length,
552 &their_key);
553 if (status != PSA_SUCCESS) {
554 goto exit;
555 }
556
557 status = mbedtls_to_psa_error(
558 mbedtls_ecdh_get_params(&ecdh, their_key, MBEDTLS_ECDH_THEIRS));
559 if (status != PSA_SUCCESS) {
560 goto exit;
561 }
562 status = mbedtls_to_psa_error(
563 mbedtls_ecdh_get_params(&ecdh, ecp, MBEDTLS_ECDH_OURS));
564 if (status != PSA_SUCCESS) {
565 goto exit;
566 }
567
568 status = mbedtls_to_psa_error(
569 mbedtls_ecdh_calc_secret(&ecdh,
570 shared_secret_length,
571 shared_secret, shared_secret_size,
572 mbedtls_psa_get_random,
573 MBEDTLS_PSA_RANDOM_STATE));
574 if (status != PSA_SUCCESS) {
575 goto exit;
576 }
577 if (PSA_BITS_TO_BYTES(bits) != *shared_secret_length) {
578 status = PSA_ERROR_CORRUPTION_DETECTED;
579 }
580 exit:
581 if (status != PSA_SUCCESS) {
582 mbedtls_platform_zeroize(shared_secret, shared_secret_size);
583 }
584 mbedtls_ecdh_free(&ecdh);
585 mbedtls_ecp_keypair_free(their_key);
586 mbedtls_free(their_key);
587 mbedtls_ecp_keypair_free(ecp);
588 mbedtls_free(ecp);
589 return status;
590 }
591 #endif /* MBEDTLS_PSA_BUILTIN_ALG_ECDH */
592
593
594 #endif /* MBEDTLS_PSA_CRYPTO_C */
595