Merge pull request #7391 from valeriosetti/issue7387

PK: don't use mbedtls_ecp_check_pub_priv() when USE_PSA is enabled
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Manuel Pégourié-Gonnard 2023-04-07 10:17:18 +02:00 committed by GitHub
commit f740767c00
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2 changed files with 87 additions and 0 deletions

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@ -1095,13 +1095,91 @@ cleanup:
}
#endif /* MBEDTLS_ECDSA_C && MBEDTLS_ECP_RESTARTABLE */
#if defined(MBEDTLS_USE_PSA_CRYPTO)
/*
* Alternative function used to verify that the EC private/public key pair
* is valid using PSA functions instead of ECP ones.
* The flow is:
* - import the private key "prv" to PSA and export its public part
* - write the raw content of public key "pub" to a local buffer
* - compare the two buffers
*/
static int eckey_check_pair_psa(const void *pub, const void *prv)
{
psa_status_t status;
psa_key_attributes_t key_attr = PSA_KEY_ATTRIBUTES_INIT;
mbedtls_ecp_keypair *prv_ctx = (mbedtls_ecp_keypair *) prv;
mbedtls_ecp_keypair *pub_ctx = (mbedtls_ecp_keypair *) pub;
int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
/* We are using MBEDTLS_PSA_MAX_EC_PUBKEY_LENGTH for the size of this
* buffer because it will be used to hold the private key at first and
* then its public part (but not at the same time). */
uint8_t prv_key_buf[MBEDTLS_PSA_MAX_EC_PUBKEY_LENGTH];
size_t prv_key_len;
uint8_t pub_key_buf[MBEDTLS_PSA_MAX_EC_PUBKEY_LENGTH];
size_t pub_key_len;
mbedtls_svc_key_id_t key_id = MBEDTLS_SVC_KEY_ID_INIT;
size_t curve_bits;
const psa_ecc_family_t curve =
mbedtls_ecc_group_to_psa(prv_ctx->grp.id, &curve_bits);
const size_t curve_bytes = PSA_BITS_TO_BYTES(curve_bits);
psa_set_key_type(&key_attr, PSA_KEY_TYPE_ECC_KEY_PAIR(curve));
psa_set_key_usage_flags(&key_attr, PSA_KEY_USAGE_EXPORT);
ret = mbedtls_mpi_write_binary(&prv_ctx->d, prv_key_buf, curve_bytes);
if (ret != 0) {
return ret;
}
status = psa_import_key(&key_attr, prv_key_buf, curve_bytes, &key_id);
if (status != PSA_SUCCESS) {
ret = PSA_PK_TO_MBEDTLS_ERR(status);
return ret;
}
mbedtls_platform_zeroize(prv_key_buf, sizeof(prv_key_buf));
ret = PSA_PK_TO_MBEDTLS_ERR(psa_export_public_key(key_id,
prv_key_buf,
sizeof(prv_key_buf),
&prv_key_len));
status = psa_destroy_key(key_id);
if (ret != 0 || status != PSA_SUCCESS) {
return (ret != 0) ? ret : PSA_PK_TO_MBEDTLS_ERR(status);
}
ret = mbedtls_ecp_point_write_binary(&pub_ctx->grp, &pub_ctx->Q,
MBEDTLS_ECP_PF_UNCOMPRESSED,
&pub_key_len, pub_key_buf,
sizeof(pub_key_buf));
if (ret != 0) {
return ret;
}
if (memcmp(prv_key_buf, pub_key_buf, curve_bytes) != 0) {
return MBEDTLS_ERR_PK_BAD_INPUT_DATA;
}
return 0;
}
#endif /* MBEDTLS_USE_PSA_CRYPTO */
static int eckey_check_pair(const void *pub, const void *prv,
int (*f_rng)(void *, unsigned char *, size_t),
void *p_rng)
{
#if defined(MBEDTLS_USE_PSA_CRYPTO)
(void) f_rng;
(void) p_rng;
return eckey_check_pair_psa((const mbedtls_ecp_keypair *) pub,
(const mbedtls_ecp_keypair *) prv);
#else /* MBEDTLS_USE_PSA_CRYPTO */
return mbedtls_ecp_check_pub_priv((const mbedtls_ecp_keypair *) pub,
(const mbedtls_ecp_keypair *) prv,
f_rng, p_rng);
#endif /* MBEDTLS_USE_PSA_CRYPTO */
return MBEDTLS_ERR_PK_FEATURE_UNAVAILABLE;
}
static void *eckey_alloc_wrap(void)

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@ -489,6 +489,15 @@ void mbedtls_pk_check_pair(char *pub_file, char *prv_file, int ret)
mbedtls_pk_init(&prv);
mbedtls_pk_init(&alt);
#if defined(MBEDTLS_USE_PSA_CRYPTO)
/* mbedtls_pk_check_pair() returns either PK or ECP error codes depending
on MBEDTLS_USE_PSA_CRYPTO so here we dynamically translate between the
two */
if (ret == MBEDTLS_ERR_ECP_BAD_INPUT_DATA) {
ret = MBEDTLS_ERR_PK_BAD_INPUT_DATA;
}
#endif
TEST_ASSERT(mbedtls_pk_parse_public_keyfile(&pub, pub_file) == 0);
TEST_ASSERT(mbedtls_pk_parse_keyfile(&prv, prv_file, NULL,
mbedtls_test_rnd_std_rand, NULL)