static
int gen_auth_key(mbedtls_ecdh_context *key, const char *tempKey,
const char *salt, unsigned char *buf, size_t bufLen) {
int ret = 0;
size_t olen = 0;
if ((errno = dslink_base64_url_decode(buf, bufLen, &olen,
(unsigned char *) tempKey,
strlen(tempKey))) != 0) {
ret = DSLINK_CRYPT_BASE64_URL_DECODE_ERR;
goto exit;
}
if ((errno = mbedtls_ecp_point_read_binary(&key->grp, &key->Qp,
buf, olen)) != 0) {
ret = DSLINK_HANDSHAKE_INVALID_TMP_KEY;
goto exit;
}
if ((errno = mbedtls_ecdh_calc_secret(key, &olen, buf,
bufLen, NULL, NULL)) != 0) {
ret = DSLINK_HANDSHAKE_INVALID_TMP_KEY;
goto exit;
}
{
size_t saltLen = strlen(salt);
size_t len = saltLen + olen;
char *in = malloc(len + 1);
if (!in) {
ret = DSLINK_ALLOC_ERR;
goto exit;
}
memcpy(in, salt, saltLen);
memcpy(in + saltLen, (char *) buf, olen);
*(in + len) = '\0';
unsigned char auth[32];
mbedtls_sha256((unsigned char *) in, len, auth, 0);
free(in);
if ((errno = dslink_base64_url_encode(buf, bufLen, &olen, auth,
sizeof(auth))) != 0) {
ret = DSLINK_CRYPT_BASE64_URL_ENCODE_ERR;
}
}
exit:
return ret;
}
TEE_Result crypto_acipher_ecc_shared_secret(struct ecc_keypair *private_key,
struct ecc_public_key *public_key,
void *secret,
unsigned long *secret_len)
{
TEE_Result res = TEE_SUCCESS;
int lmd_res = 0;
uint8_t one[1] = { 1 };
mbedtls_ecdh_context ecdh;
size_t out_len = 0;
memset(&ecdh, 0, sizeof(ecdh));
mbedtls_ecdh_init(&ecdh);
lmd_res = mbedtls_ecp_group_load(&ecdh.grp, private_key->curve);
if (lmd_res != 0) {
res = TEE_ERROR_NOT_SUPPORTED;
goto out;
}
ecdh.d = *(mbedtls_mpi *)private_key->d;
ecdh.Qp.X = *(mbedtls_mpi *)public_key->x;
ecdh.Qp.Y = *(mbedtls_mpi *)public_key->y;
mbedtls_mpi_read_binary(&ecdh.Qp.Z, one, sizeof(one));
lmd_res = mbedtls_ecdh_calc_secret(&ecdh, &out_len, secret,
*secret_len, mbd_rand, NULL);
if (lmd_res != 0) {
res = get_tee_result(lmd_res);
goto out;
}
*secret_len = out_len;
out:
/* Reset mpi to skip freeing here, those mpis will be freed with key */
mbedtls_mpi_init(&ecdh.d);
mbedtls_mpi_init(&ecdh.Qp.X);
mbedtls_mpi_init(&ecdh.Qp.Y);
mbedtls_ecdh_free(&ecdh);
return res;
}
