u2f_service.h

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/*******************************************************************************
 *   Ledger Nano S - Secure firmware
 *   (c) 2022 Ledger
 *
 *  Licensed under the Apache License, Version 2.0 (the "License");
 *  you may not use this file except in compliance with the License.
 *  You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 *  Unless required by applicable law or agreed to in writing, software
 *  distributed under the License is distributed on an "AS IS" BASIS,
 *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 *  See the License for the specific language governing permissions and
 *  limitations under the License.
 ********************************************************************************/
 
#include <stdint.h>
#include <string.h>
#include <stdbool.h>
 
#ifndef __U2F_SERVICE_H__
 
#define __U2F_SERVICE_H__
 
#define U2F_CHANNEL_ID_SIZE 4
 
struct u2f_service_t;
 
typedef void (*u2fHandle_t)(struct u2f_service_t *service, uint8_t *inputBuffer, uint8_t *channel);
typedef void (*u2fPromptUserPresence_t)(struct u2f_service_t *service,
                                        bool                  enroll,
                                        uint8_t              *applicationParameter);
typedef void (*u2fTimer_t)(struct u2f_service_t *service);
 
typedef enum {
    U2F_IDLE,
    U2F_HANDLE_SEGMENTED,
    U2F_PROCESSING_COMMAND,
    U2F_SENDING_RESPONSE,
    U2F_SENDING_ERROR,
    U2F_INTERNAL_ERROR,
    U2F_FAKE_RECEIVED,
} u2f_transport_state_t;
 
typedef enum {
    U2F_MEDIA_NONE,
    U2F_MEDIA_USB,
    U2F_MEDIA_NFC,
    U2F_MEDIA_BLE
} u2f_transport_media_t;
 
typedef enum {
    U2F_WAIT_ASYNCH_IDLE,
    U2F_WAIT_ASYNCH_ON,
    U2F_WAIT_ASYNCH_REPLY_READY,
} u2f_wait_asynch_state_t;
 
typedef struct u2f_service_t {
    // Internal
    uint32_t next_channel;
 
    uint8_t               channel[U2F_CHANNEL_ID_SIZE];
    u2f_transport_media_t media;
 
    // buffer reference used when transport layer is reset, to process and receive the next message
    uint8_t *transportReceiveBuffer;
    // length of the receive buffer to avoid overflows
    uint16_t transportReceiveBufferLength;
 
    uint8_t               transportChannel[4];
    uint16_t              transportOffset;
    uint16_t              transportLength;
    uint8_t               transportPacketIndex;
    uint8_t              *transportBuffer;
    u2f_transport_state_t transportState;
    u2f_transport_media_t transportMedia;
 
    // handle fake channel state to simulate a USB keepalive
    uint16_t              fakeChannelTransportOffset;
    uint8_t               fakeChannelTransportPacketIndex;
    u2f_transport_state_t fakeChannelTransportState;
    uint16_t              commandCrc;
    uint16_t              fakeChannelCrc;
 
    // mark that an asynchronous response is available
    uint8_t waitAsynchronousResponse;
 
    // uint16_t responseLength;
    bool sending;
 
    u2fTimer_t timeoutFunction;
    uint32_t   timerInterval;
    uint32_t   seqTimeout;
    bool       requireKeepalive;
    uint32_t   keepaliveTimeout;
 
    uint8_t sendCmd;
} u2f_service_t;
 
void u2f_message_complete(u2f_service_t *service);
 
// FIDO 2 compatible applications have to provide those implementations
 
void ctap2_handle_cmd_cbor(u2f_service_t *service, uint8_t *buffer, uint16_t length);
void ctap2_handle_cmd_cancel(u2f_service_t *service, uint8_t *buffer, uint16_t length);
 
#endif