diff --git a/library/ssl_tls12_client.c b/library/ssl_tls12_client.c index 734d3a2e97..ad5b55477d 100644 --- a/library/ssl_tls12_client.c +++ b/library/ssl_tls12_client.c @@ -1813,6 +1813,7 @@ static int ssl_check_server_ecdh_params( const mbedtls_ssl_context *ssl ) #if defined(MBEDTLS_USE_PSA_CRYPTO) && \ ( defined(MBEDTLS_KEY_EXCHANGE_ECDHE_RSA_ENABLED) || \ + defined(MBEDTLS_KEY_EXCHANGE_ECDHE_PSK_ENABLED) || \ defined(MBEDTLS_KEY_EXCHANGE_ECDHE_ECDSA_ENABLED) ) static int ssl_parse_server_ecdh_params_psa( mbedtls_ssl_context *ssl, unsigned char **p, @@ -2348,8 +2349,10 @@ start_processing: MBEDTLS_KEY_EXCHANGE_DHE_PSK_ENABLED */ #if defined(MBEDTLS_USE_PSA_CRYPTO) && \ ( defined(MBEDTLS_KEY_EXCHANGE_ECDHE_RSA_ENABLED) || \ + defined(MBEDTLS_KEY_EXCHANGE_ECDHE_PSK_ENABLED) || \ defined(MBEDTLS_KEY_EXCHANGE_ECDHE_ECDSA_ENABLED) ) if( ciphersuite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_ECDHE_RSA || + ciphersuite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_ECDHE_PSK || ciphersuite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_ECDHE_ECDSA ) { if( ssl_parse_server_ecdh_params_psa( ssl, &p, end ) != 0 ) @@ -2365,6 +2368,7 @@ start_processing: else #endif /* MBEDTLS_USE_PSA_CRYPTO && ( MBEDTLS_KEY_EXCHANGE_ECDHE_RSA_ENABLED || + MBEDTLS_KEY_EXCHANGE_ECDHE_PSK_ENABLED || MBEDTLS_KEY_EXCHANGE_ECDHE_ECDSA_ENABLED ) */ #if defined(MBEDTLS_KEY_EXCHANGE_ECDHE_RSA_ENABLED) || \ defined(MBEDTLS_KEY_EXCHANGE_ECDHE_PSK_ENABLED) || \ @@ -2998,6 +3002,149 @@ ecdh_calc_secret: MBEDTLS_KEY_EXCHANGE_ECDHE_ECDSA_ENABLED || MBEDTLS_KEY_EXCHANGE_ECDH_RSA_ENABLED || MBEDTLS_KEY_EXCHANGE_ECDH_ECDSA_ENABLED */ +#if defined(MBEDTLS_USE_PSA_CRYPTO) && \ + defined(MBEDTLS_KEY_EXCHANGE_ECDHE_PSK_ENABLED) + if( ciphersuite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_ECDHE_PSK ) + { + psa_status_t status = PSA_ERROR_CORRUPTION_DETECTED; + psa_status_t destruction_status = PSA_ERROR_CORRUPTION_DETECTED; + psa_key_attributes_t key_attributes; + + mbedtls_ssl_handshake_params *handshake = ssl->handshake; + + /* + * opaque psk_identity<0..2^16-1>; + */ + if( mbedtls_ssl_conf_has_static_psk( ssl->conf ) == 0 ) + { + /* We don't offer PSK suites if we don't have a PSK, + * and we check that the server's choice is among the + * ciphersuites we offered, so this should never happen. */ + return( MBEDTLS_ERR_SSL_INTERNAL_ERROR ); + } + + /* Opaque PSKs are currently only supported for PSK-only suites. */ + if( ssl_conf_has_static_raw_psk( ssl->conf ) == 0 ) + return( MBEDTLS_ERR_SSL_FEATURE_UNAVAILABLE ); + + header_len = 4; + content_len = ssl->conf->psk_identity_len; + + if( header_len + 2 + content_len > MBEDTLS_SSL_OUT_CONTENT_LEN ) + { + MBEDTLS_SSL_DEBUG_MSG( 1, + ( "psk identity too long or SSL buffer too short" ) ); + return( MBEDTLS_ERR_SSL_BUFFER_TOO_SMALL ); + } + + ssl->out_msg[header_len++] = MBEDTLS_BYTE_1( content_len ); + ssl->out_msg[header_len++] = MBEDTLS_BYTE_0( content_len ); + + memcpy( ssl->out_msg + header_len, + ssl->conf->psk_identity, + ssl->conf->psk_identity_len ); + header_len += ssl->conf->psk_identity_len; + + MBEDTLS_SSL_DEBUG_MSG( 1, ( "Perform PSA-based ECDH computation." ) ); + + /* + * Generate EC private key for ECDHE exchange. + */ + + /* The master secret is obtained from the shared ECDH secret by + * applying the TLS 1.2 PRF with a specific salt and label. While + * the PSA Crypto API encourages combining key agreement schemes + * such as ECDH with fixed KDFs such as TLS 1.2 PRF, it does not + * yet support the provisioning of salt + label to the KDF. + * For the time being, we therefore need to split the computation + * of the ECDH secret and the application of the TLS 1.2 PRF. */ + key_attributes = psa_key_attributes_init(); + psa_set_key_usage_flags( &key_attributes, PSA_KEY_USAGE_DERIVE ); + psa_set_key_algorithm( &key_attributes, PSA_ALG_ECDH ); + psa_set_key_type( &key_attributes, handshake->ecdh_psa_type ); + psa_set_key_bits( &key_attributes, handshake->ecdh_bits ); + + /* Generate ECDH private key. */ + status = psa_generate_key( &key_attributes, + &handshake->ecdh_psa_privkey ); + if( status != PSA_SUCCESS ) + return( MBEDTLS_ERR_SSL_HW_ACCEL_FAILED ); + + /* Export the public part of the ECDH private key from PSA. + * The export format is an ECPoint structure as expected by TLS, + * but we just need to add a length byte before that. */ + unsigned char *own_pubkey = ssl->out_msg + header_len + 1; + unsigned char *end = ssl->out_msg + MBEDTLS_SSL_OUT_CONTENT_LEN; + size_t own_pubkey_max_len = (size_t)( end - own_pubkey ); + size_t own_pubkey_len; + + status = psa_export_public_key( handshake->ecdh_psa_privkey, + own_pubkey, own_pubkey_max_len, + &own_pubkey_len ); + if( status != PSA_SUCCESS ) + { + psa_destroy_key( handshake->ecdh_psa_privkey ); + handshake->ecdh_psa_privkey = MBEDTLS_SVC_KEY_ID_INIT; + return( MBEDTLS_ERR_SSL_HW_ACCEL_FAILED ); + } + + ssl->out_msg[header_len] = (unsigned char) own_pubkey_len; + content_len = own_pubkey_len + 1; + + /* The ECDH secret is the premaster secret used for key derivation. */ + unsigned char *p = ssl->handshake->premaster; + unsigned char *p_end = p + sizeof( ssl->handshake->premaster ); + size_t zlen; + + /* Compute ECDH shared secret. */ + status = psa_raw_key_agreement( PSA_ALG_ECDH, + handshake->ecdh_psa_privkey, + handshake->ecdh_psa_peerkey, + handshake->ecdh_psa_peerkey_len, + p + 2, + p_end - ( p + 2 ), + &zlen ); + + destruction_status = psa_destroy_key( handshake->ecdh_psa_privkey ); + handshake->ecdh_psa_privkey = MBEDTLS_SVC_KEY_ID_INIT; + + if( status != PSA_SUCCESS || destruction_status != PSA_SUCCESS ) + return( MBEDTLS_ERR_SSL_HW_ACCEL_FAILED ); + + MBEDTLS_PUT_UINT16_BE( zlen, p, 0 ); + p += 2 + zlen; + + /* opaque psk<0..2^16-1>; */ + if( p_end - p < 2 ) + return( MBEDTLS_ERR_SSL_BAD_INPUT_DATA ); + + const unsigned char *psk = NULL; + size_t psk_len = 0; + + if( mbedtls_ssl_get_psk( ssl, &psk, &psk_len ) + == MBEDTLS_ERR_SSL_PRIVATE_KEY_REQUIRED ) + { + /* + * This should never happen because the existence of a PSK is always + * checked before calling this function + */ + return( MBEDTLS_ERR_SSL_INTERNAL_ERROR ); + } + + MBEDTLS_PUT_UINT16_BE( psk_len, p, 0 ); + p += 2; + + if( p_end < p || (size_t)( p_end - p ) < psk_len ) + return( MBEDTLS_ERR_SSL_BAD_INPUT_DATA ); + + memcpy( p, psk, psk_len ); + p += psk_len; + + ssl->handshake->pmslen = p - ssl->handshake->premaster; + } + else +#endif /* MBEDTLS_USE_PSA_CRYPTO && + MBEDTLS_KEY_EXCHANGE_ECDHE_PSK_ENABLED */ #if defined(MBEDTLS_KEY_EXCHANGE_SOME_PSK_ENABLED) if( mbedtls_ssl_ciphersuite_uses_psk( ciphersuite_info ) ) {