/*
* Compute and write signature
*/
int mbedtls_ecdsa_write_signature( mbedtls_ecdsa_context *ctx, mbedtls_md_type_t md_alg,
const unsigned char *hash, size_t hlen,
unsigned char *sig, size_t *slen,
int (*f_rng)(void *, unsigned char *, size_t),
void *p_rng )
{
int ret;
mbedtls_mpi r, s;
mbedtls_mpi_init( &r );
mbedtls_mpi_init( &s );
#if defined(MBEDTLS_ECDSA_DETERMINISTIC)
(void) f_rng;
(void) p_rng;
MBEDTLS_MPI_CHK( mbedtls_ecdsa_sign_det( &ctx->grp, &r, &s, &ctx->d,
hash, hlen, md_alg ) );
#else
(void) md_alg;
MBEDTLS_MPI_CHK( mbedtls_ecdsa_sign( &ctx->grp, &r, &s, &ctx->d,
hash, hlen, f_rng, p_rng ) );
#endif
MBEDTLS_MPI_CHK( ecdsa_signature_to_asn1( &r, &s, sig, slen ) );
cleanup:
mbedtls_mpi_free( &r );
mbedtls_mpi_free( &s );
return( ret );
}
/*
* Deterministic signature wrapper
*/
int mbedtls_ecdsa_sign_det( mbedtls_ecp_group *grp, mbedtls_mpi *r, mbedtls_mpi *s,
const mbedtls_mpi *d, const unsigned char *buf, size_t blen,
mbedtls_md_type_t md_alg )
{
int ret;
mbedtls_hmac_drbg_context rng_ctx;
unsigned char data[2 * MBEDTLS_ECP_MAX_BYTES];
size_t grp_len = ( grp->nbits + 7 ) / 8;
const mbedtls_md_info_t *md_info;
mbedtls_mpi h;
if( ( md_info = mbedtls_md_info_from_type( md_alg ) ) == NULL )
return( MBEDTLS_ERR_ECP_BAD_INPUT_DATA );
mbedtls_mpi_init( &h );
mbedtls_hmac_drbg_init( &rng_ctx );
/* Use private key and message hash (reduced) to initialize HMAC_DRBG */
MBEDTLS_MPI_CHK( mbedtls_mpi_write_binary( d, data, grp_len ) );
MBEDTLS_MPI_CHK( derive_mpi( grp, &h, buf, blen ) );
MBEDTLS_MPI_CHK( mbedtls_mpi_write_binary( &h, data + grp_len, grp_len ) );
mbedtls_hmac_drbg_seed_buf( &rng_ctx, md_info, data, 2 * grp_len );
ret = mbedtls_ecdsa_sign( grp, r, s, d, buf, blen,
mbedtls_hmac_drbg_random, &rng_ctx );
cleanup:
mbedtls_hmac_drbg_free( &rng_ctx );
mbedtls_mpi_free( &h );
return( ret );
}
TEE_Result crypto_acipher_ecc_sign(uint32_t algo, struct ecc_keypair *key,
const uint8_t *msg, size_t msg_len,
uint8_t *sig, size_t *sig_len)
{
TEE_Result res = TEE_SUCCESS;
int lmd_res = 0;
const mbedtls_pk_info_t *pk_info = NULL;
mbedtls_ecdsa_context ecdsa;
size_t key_size_bytes = 0;
size_t key_size_bits = 0;
mbedtls_mpi r;
mbedtls_mpi s;
memset(&ecdsa, 0, sizeof(ecdsa));
memset(&r, 0, sizeof(r));
memset(&s, 0, sizeof(s));
if (algo == 0)
return TEE_ERROR_BAD_PARAMETERS;
mbedtls_mpi_init(&r);
mbedtls_mpi_init(&s);
mbedtls_ecdsa_init(&ecdsa);
lmd_res = mbedtls_ecp_group_load(&ecdsa.grp, key->curve);
if (lmd_res != 0) {
res = TEE_ERROR_NOT_SUPPORTED;
goto out;
}
ecdsa.d = *(mbedtls_mpi *)key->d;
res = ecc_get_keysize(key->curve, algo, &key_size_bytes,
&key_size_bits);
if (res != TEE_SUCCESS)
goto out;
pk_info = mbedtls_pk_info_from_type(MBEDTLS_PK_ECDSA);
if (pk_info == NULL) {
res = TEE_ERROR_NOT_SUPPORTED;
goto out;
}
lmd_res = mbedtls_ecdsa_sign(&ecdsa.grp, &r, &s, &ecdsa.d, msg,
msg_len, mbd_rand, NULL);
if (lmd_res == 0) {
*sig_len = 2 * key_size_bytes;
memset(sig, 0, *sig_len);
mbedtls_mpi_write_binary(&r, sig + *sig_len / 2 -
mbedtls_mpi_size(&r),
mbedtls_mpi_size(&r));
mbedtls_mpi_write_binary(&s, sig + *sig_len -
mbedtls_mpi_size(&s),
mbedtls_mpi_size(&s));
res = TEE_SUCCESS;
} else {
FMSG("mbedtls_ecdsa_sign failed, returned 0x%x\n", -lmd_res);
res = TEE_ERROR_GENERIC;
}
out:
mbedtls_mpi_free(&r);
mbedtls_mpi_free(&s);
/* Reset mpi to skip freeing here, those mpis will be freed with key */
mbedtls_mpi_init(&ecdsa.d);
mbedtls_ecdsa_free(&ecdsa);
return res;
}
/*
* Deterministic signature wrapper
*/
static int ecdsa_sign_det_restartable( mbedtls_ecp_group *grp,
mbedtls_mpi *r, mbedtls_mpi *s,
const mbedtls_mpi *d, const unsigned char *buf, size_t blen,
mbedtls_md_type_t md_alg,
mbedtls_ecdsa_restart_ctx *rs_ctx )
{
int ret;
mbedtls_hmac_drbg_context rng_ctx;
mbedtls_hmac_drbg_context *p_rng = &rng_ctx;
unsigned char data[2 * MBEDTLS_ECP_MAX_BYTES];
size_t grp_len = ( grp->nbits + 7 ) / 8;
const mbedtls_md_info_t *md_info;
mbedtls_mpi h;
if( ( md_info = mbedtls_md_info_from_type( md_alg ) ) == NULL )
return( MBEDTLS_ERR_ECP_BAD_INPUT_DATA );
mbedtls_mpi_init( &h );
mbedtls_hmac_drbg_init( &rng_ctx );
ECDSA_RS_ENTER( det );
#if defined(MBEDTLS_ECP_RESTARTABLE)
if( rs_ctx != NULL && rs_ctx->det != NULL )
{
/* redirect to our context */
p_rng = &rs_ctx->det->rng_ctx;
/* jump to current step */
if( rs_ctx->det->state == ecdsa_det_sign )
goto sign;
}
#endif /* MBEDTLS_ECP_RESTARTABLE */
/* Use private key and message hash (reduced) to initialize HMAC_DRBG */
MBEDTLS_MPI_CHK( mbedtls_mpi_write_binary( d, data, grp_len ) );
MBEDTLS_MPI_CHK( derive_mpi( grp, &h, buf, blen ) );
MBEDTLS_MPI_CHK( mbedtls_mpi_write_binary( &h, data + grp_len, grp_len ) );
mbedtls_hmac_drbg_seed_buf( p_rng, md_info, data, 2 * grp_len );
#if defined(MBEDTLS_ECP_RESTARTABLE)
if( rs_ctx != NULL && rs_ctx->det != NULL )
rs_ctx->det->state = ecdsa_det_sign;
sign:
#endif
#if defined(MBEDTLS_ECDSA_SIGN_ALT)
ret = mbedtls_ecdsa_sign( grp, r, s, d, buf, blen,
mbedtls_hmac_drbg_random, p_rng );
#else
ret = ecdsa_sign_restartable( grp, r, s, d, buf, blen,
mbedtls_hmac_drbg_random, p_rng, rs_ctx );
#endif /* MBEDTLS_ECDSA_SIGN_ALT */
cleanup:
mbedtls_hmac_drbg_free( &rng_ctx );
mbedtls_mpi_free( &h );
ECDSA_RS_LEAVE( det );
return( ret );
}
