messages.c

/*
 * This file is part of the TREZOR project, https://trezor.io/
 *
 * Copyright (C) 2014 Pavol Rusnak <stick@satoshilabs.com>
 *
 * This library is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Lesser General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public License
 * along with this library.  If not, see <http://www.gnu.org/licenses/>.
 */

#include <string.h>

#include "tiny-firmware/firmware/fsm.h"
#include "tiny-firmware/firmware/fsm_skycoin.h"
#include "tiny-firmware/firmware/fsm_bitcoin.h"
#include "tiny-firmware/util.h"
#include "tiny-firmware/firmware/gettext.h"
#include "tiny-firmware/firmware/messages.h"
#include "tiny-firmware/firmware/skywallet.h"

#include "messages.pb.h"
#include "bitcoin_messages.pb.h"
#include "pb_decode.h"
#include "pb_encode.h"

struct MessagesMap_t {
    char type; // n = normal, d = debug
    char dir;  // i = in, o = out
    uint16_t msg_id;
    const pb_field_t *fields;

    void (*process_func)(void *ptr);
};

static const struct MessagesMap_t MessagesMap[] = {
#include "messages_map.h"
        // end
        {0, 0, 0, 0, 0}};

const pb_field_t *MessageFields(char type, char dir, uint16_t msg_id) {
    const struct MessagesMap_t *m = MessagesMap;
    while (m->type) {
#if EMULATOR
        (void) type;
        if (dir == m->dir && msg_id == m->msg_id) {
#else
            if (type == m->type && dir == m->dir && msg_id == m->msg_id) {
#endif
            return m->fields;
        }
        m++;
    }
    return 0;
}

void MessageProcessFunc(char type, char dir, uint16_t msg_id, void *ptr) {
    const struct MessagesMap_t *m = MessagesMap;
    while (m->type) {
#if EMULATOR
        (void) type;
        if (dir == m->dir && msg_id == m->msg_id) {
#else
            if (type == m->type && dir == m->dir && msg_id == m->msg_id) {
#endif
            m->process_func(ptr);
            return;
        }
        m++;
    }
}

static uint32_t msg_out_start = 0;
static uint32_t msg_out_end = 0;
static uint32_t msg_out_cur = 0;
static uint8_t msg_out[MSG_OUT_SIZE];


static inline void msg_out_append(uint8_t c) {
    if (msg_out_cur == 0) {
        msg_out[msg_out_end * 64] = '?';
        msg_out_cur = 1;
    }
    msg_out[msg_out_end * 64 + msg_out_cur] = c;
    msg_out_cur++;
    if (msg_out_cur == 64) {
        msg_out_cur = 0;
        msg_out_end = (msg_out_end + 1) % (MSG_OUT_SIZE / 64);
    }
}

static inline void msg_out_pad(void) {
    if (msg_out_cur == 0) return;
    while (msg_out_cur < 64) {
        msg_out[msg_out_end * 64 + msg_out_cur] = 0;
        msg_out_cur++;
    }
    msg_out_cur = 0;
    msg_out_end = (msg_out_end + 1) % (MSG_OUT_SIZE / 64);
}

static bool pb_callback_out(pb_ostream_t *stream, const uint8_t *buf, size_t count) {
    (void) stream;
    for (size_t i = 0; i < count; i++) {
        msg_out_append(buf[i]);
    }
    return true;
}

bool msg_write_common(char type, uint16_t msg_id, const void *msg_ptr) {
    const pb_field_t *fields = MessageFields(type, 'o', msg_id);
    if (!fields) { // unknown message
        return false;
    }

    pb_ostream_t sizestream = {0, 0, SIZE_MAX, 0, 0};
    bool status = pb_encode(&sizestream, fields, msg_ptr);

    if (!status) {
        return false;
    }

    void (*append)(uint8_t);
    bool (*pb_callback)(pb_ostream_t *, const uint8_t *, size_t);

    if (type == 'n') {
        append = msg_out_append;
        pb_callback = pb_callback_out;
    } else {
        return false;
    }

    uint32_t len = sizestream.bytes_written;
    append('#');
    append('#');
    append((msg_id >> 8) & 0xFF);
    append(msg_id & 0xFF);
    append((len >> 24) & 0xFF);
    append((len >> 16) & 0xFF);
    append((len >> 8) & 0xFF);
    append(len & 0xFF);
    pb_ostream_t stream = {pb_callback, 0, SIZE_MAX, 0, 0};
    status = pb_encode(&stream, fields, msg_ptr);
    if (type == 'n') {
        msg_out_pad();
    }
    return status;
}

enum {
    READSTATE_IDLE,
    READSTATE_READING,
};

void msg_process(char type, uint16_t msg_id, const pb_field_t *fields, uint8_t *msg_raw, uint32_t msg_size) {
    static CONFIDENTIAL uint8_t msg_data[MSG_IN_SIZE];
    memset(msg_data, 0, sizeof(msg_data));
    pb_istream_t stream = pb_istream_from_buffer(msg_raw, msg_size);
    bool status = pb_decode(&stream, fields, msg_data);
    if (status) {
        MessageProcessFunc(type, 'i', msg_id, msg_data);
    } else {
        fsm_sendFailure(FailureType_Failure_DataError, stream.errmsg, 0);
    }
}

void msg_read_common(char type, const uint8_t *buf, int len) {
    static char read_state = READSTATE_IDLE;
    static CONFIDENTIAL uint8_t msg_in[MSG_IN_SIZE];
    static uint16_t msg_id = 0xFFFF;
    static uint32_t msg_size = 0;
    static uint32_t msg_pos = 0;
    static const pb_field_t *fields = 0;

    if (len != 64) return;

    if (read_state == READSTATE_IDLE) {
        if (buf[0] != '?' || buf[1] != '#' || buf[2] != '#') { // invalid start - discard
            return;
        }
        msg_id = (buf[3] << 8) + buf[4];
        msg_size = ((uint32_t) buf[5] << 24) + (buf[6] << 16) + (buf[7] << 8) + buf[8];

        fields = MessageFields(type, 'i', msg_id);
        if (!fields) { // unknown message
            fsm_sendFailure(FailureType_Failure_UnexpectedMessage, _("Unknown message read_common"), 0);
            return;
        }
        if (msg_size > MSG_IN_SIZE) { // message is too big :(
            fsm_sendFailure(FailureType_Failure_DataError, _("Message too big"), 0);
            return;
        }

        read_state = READSTATE_READING;

        memcpy(msg_in, buf + 9, len - 9);
        msg_pos = len - 9;
    } else if (read_state == READSTATE_READING) {
        if (buf[0] != '?') { // invalid contents
            read_state = READSTATE_IDLE;
            return;
        }
        memcpy(msg_in + msg_pos, buf + 1, len - 1);
        msg_pos += len - 1;
    }

    if (msg_pos >= msg_size) {
        msg_process(type, msg_id, fields, msg_in, msg_size);
        msg_pos = 0;
        read_state = READSTATE_IDLE;
    }
}

const uint8_t *msg_out_data(void) {
    if (msg_out_start == msg_out_end) return 0;
    uint8_t *data = msg_out + (msg_out_start * 64);
    msg_out_start = (msg_out_start + 1) % (MSG_OUT_SIZE / 64);
    return data;
}


CONFIDENTIAL uint8_t msg_tiny[128];
_Static_assert(sizeof(msg_tiny) >= sizeof(Cancel), "msg_tiny too tiny");
_Static_assert(sizeof(msg_tiny) >= sizeof(Initialize), "msg_tiny too tiny");
_Static_assert(sizeof(msg_tiny) >= sizeof(PassphraseAck), "msg_tiny too tiny");
_Static_assert(sizeof(msg_tiny) >= sizeof(ButtonAck), "msg_tiny too tiny");
_Static_assert(sizeof(msg_tiny) >= sizeof(PinMatrixAck), "msg_tiny too tiny");
#if DEBUG_LINK
_Static_assert(sizeof(msg_tiny) >= sizeof(DebugLinkDecision), "msg_tiny too tiny");
_Static_assert(sizeof(msg_tiny) >= sizeof(DebugLinkGetState), "msg_tiny too tiny");
#endif
uint16_t msg_tiny_id = 0xFFFF;

void msg_read_tiny(const uint8_t *buf, int len) {
    if (len != 64) return;
    if (buf[0] != '?' || buf[1] != '#' || buf[2] != '#') {
        return;
    }
    uint16_t msg_id = (buf[3] << 8) + buf[4];
    uint32_t msg_size = (buf[5] << 24) + (buf[6] << 16) + (buf[7] << 8) + buf[8];
    if (msg_size > 64 || len - msg_size < 9) {
        return;
    }

    const pb_field_t *fields = 0;
    // upstream nanopb is missing const qualifier, so we have to cast :-/
    pb_istream_t stream = pb_istream_from_buffer((uint8_t *) buf + 9, msg_size);

    switch (msg_id) {
        case MessageType_MessageType_PinMatrixAck:
            fields = PinMatrixAck_fields;
            break;
        case MessageType_MessageType_ButtonAck:
            fields = ButtonAck_fields;
            break;
        case MessageType_MessageType_PassphraseAck:
            fields = PassphraseAck_fields;
            break;
        case MessageType_MessageType_Cancel:
            fields = Cancel_fields;
            break;
        case MessageType_MessageType_Initialize:
            fields = Initialize_fields;
            break;
    }
    if (fields) {
        bool status = pb_decode(&stream, fields, msg_tiny);
        if (status) {
            msg_tiny_id = msg_id;
        } else {
            fsm_sendFailure(FailureType_Failure_DataError, stream.errmsg, 0);
            msg_tiny_id = 0xFFFF;
        }
    } else {
        fsm_sendFailure(FailureType_Failure_UnexpectedMessage, _("Unknown message read_tiny"), 0);
        msg_tiny_id = 0xFFFF;
    }
}