PK: ECDSA signing PSA wrap implementation
Signed-off-by: Neil Armstrong <narmstrong@baylibre.com>
diff --git a/library/pk_wrap.c b/library/pk_wrap.c
index f7480c6..2d4a1e2 100644
--- a/library/pk_wrap.c
+++ b/library/pk_wrap.c
@@ -737,6 +737,106 @@
}
#endif /* MBEDTLS_USE_PSA_CRYPTO */
+#if defined(MBEDTLS_USE_PSA_CRYPTO)
+static int pk_ecdsa_sig_asn1_from_psa( unsigned char *sig, size_t *sig_len,
+ size_t buf_len );
+
+static int find_ecdsa_private_key( unsigned char **buf, unsigned char *end, size_t *key_len)
+{
+ size_t len;
+ int ret;
+
+ if( ( ret = mbedtls_asn1_get_tag( buf, end, &len,
+ MBEDTLS_ASN1_CONSTRUCTED | MBEDTLS_ASN1_SEQUENCE ) ) != 0 )
+ return( ret );
+
+ /* version */
+ if( ( ret = mbedtls_asn1_get_tag( buf, end, &len,
+ MBEDTLS_ASN1_INTEGER ) ) != 0 )
+ return( ret );
+
+ *buf += len;
+
+ /* privateKey */
+ if( ( ret = mbedtls_asn1_get_tag( buf, end, &len,
+ MBEDTLS_ASN1_OCTET_STRING ) ) != 0 )
+ return( ret );
+
+ *key_len = len;
+
+ return 0;
+}
+
+static int ecdsa_sign_wrap( void *ctx_arg, mbedtls_md_type_t md_alg,
+ const unsigned char *hash, size_t hash_len,
+ unsigned char *sig, size_t sig_size, size_t *sig_len,
+ int (*f_rng)(void *, unsigned char *, size_t), void *p_rng )
+{
+ mbedtls_ecdsa_context *ctx = ctx_arg;
+ int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
+ psa_key_attributes_t attributes = PSA_KEY_ATTRIBUTES_INIT;
+ mbedtls_svc_key_id_t key_id = MBEDTLS_SVC_KEY_ID_INIT;
+ psa_status_t status;
+ mbedtls_pk_context key;
+ size_t key_len;
+ /* see ECP_PRV_DER_MAX_BYTES in pkwrite.c */
+ unsigned char buf[29 + 3 * MBEDTLS_ECP_MAX_BYTES];
+ unsigned char *p;
+ mbedtls_pk_info_t pk_info = mbedtls_eckey_info;
+ psa_algorithm_t psa_sig_md = PSA_ALG_ECDSA( mbedtls_psa_translate_md( md_alg ) );
+ size_t curve_bits;
+ psa_ecc_family_t curve =
+ mbedtls_ecc_group_to_psa( ctx->grp.id, &curve_bits );
+ ((void) md_alg);
+
+ /* PSA has its own RNG */
+ ((void) f_rng);
+ ((void) p_rng);
+
+ if( curve == 0 )
+ return( MBEDTLS_ERR_PK_BAD_INPUT_DATA );
+
+ /* mbedtls_pk_write_key_der() expects a full PK context;
+ * re-construct one to make it happy */
+ key.pk_info = &pk_info;
+ key.pk_ctx = ctx;
+ key_len = mbedtls_pk_write_key_der( &key, buf, sizeof( buf ) );
+ if( key_len <= 0 )
+ return( MBEDTLS_ERR_PK_BAD_INPUT_DATA );
+
+ p = buf + sizeof( buf ) - key_len;
+ ret = find_ecdsa_private_key( &p, buf + sizeof( buf ), &key_len );
+ if( ret != 0 )
+ goto cleanup;
+
+ psa_set_key_type( &attributes, PSA_KEY_TYPE_ECC_KEY_PAIR( curve ) );
+ psa_set_key_usage_flags( &attributes, PSA_KEY_USAGE_SIGN_HASH );
+ psa_set_key_algorithm( &attributes, psa_sig_md );
+
+ status = psa_import_key( &attributes,
+ p, key_len,
+ &key_id );
+ if( status != PSA_SUCCESS )
+ {
+ ret = mbedtls_psa_err_translate_pk( status );
+ goto cleanup;
+ }
+
+ if( psa_sign_hash( key_id, psa_sig_md, hash, hash_len,
+ sig, sig_size, sig_len)
+ != PSA_SUCCESS )
+ {
+ ret = MBEDTLS_ERR_ECP_VERIFY_FAILED;
+ goto cleanup;
+ }
+
+ ret = pk_ecdsa_sig_asn1_from_psa( sig, sig_len, sig_size );
+
+cleanup:
+ psa_destroy_key( key_id );
+ return( ret );
+}
+#else
static int ecdsa_sign_wrap( void *ctx, mbedtls_md_type_t md_alg,
const unsigned char *hash, size_t hash_len,
unsigned char *sig, size_t sig_size, size_t *sig_len,
@@ -747,6 +847,7 @@
sig, sig_size, sig_len,
f_rng, p_rng ) );
}
+#endif
#if defined(MBEDTLS_ECP_RESTARTABLE)
static int ecdsa_verify_rs_wrap( void *ctx, mbedtls_md_type_t md_alg,