themis 0.14.0

High-level cryptographic services for storage and messaging
Documentation 
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// Copyright 2018 (c) rust-themis developers
//
// 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.

#[macro_use]
extern crate log;

use std::fs::File;
use std::io::{self, Read, Write};
use std::net::UdpSocket;
use std::process;
use std::thread;

use clap::clap_app;
use themis::keys::{PrivateKey, PublicKey};
use themis::secure_message::{SecureSign, SecureVerify};

fn main() {
    env_logger::init();

    let matches = clap_app!(secure_message_client_verify =>
        (version: env!("CARGO_PKG_VERSION"))
        (about: "Secure Message chat client (sign/verify).")
        (@arg private: --private [path] "Private key file (default: private.key)")
        (@arg public: --public [path] "Public key file (default: public.key)")
        (@arg address: -c --connect [addr] "Relay server address (default: localhost:7573)")
    )
    .get_matches();

    let private_path = matches.value_of("private").unwrap_or("private.key");
    let public_path = matches.value_of("public").unwrap_or("public.key");
    let remote_addr = matches.value_of("address").unwrap_or("localhost:7573");

    let private_key = read_file(private_path).expect("read private key");
    let private_key = PrivateKey::try_from_slice(private_key).expect("parse private key");
    let public_key = read_file(public_path).expect("read public key");
    let public_key = PublicKey::try_from_slice(public_key).expect("parse public key");

    let socket = UdpSocket::bind("localhost:0").expect("client socket");
    socket.connect(&remote_addr).expect("client connection");

    let receive_socket = socket;
    let relay_socket = receive_socket.try_clone().unwrap();

    // Each of the threads is using its own object for message processing.
    // Also note that SecureSign/SecureVerify API is deliberately different from SecureMessage.
    let receive_secure = SecureVerify::new(public_key);
    let relay_secure = SecureSign::new(private_key);

    let final_message_server = format!("client {} left chat\n", process::id())
        .as_bytes()
        .to_vec();
    let final_message_client = final_message_server.clone();

    let receive = thread::spawn(move || {
        let receive_message = || -> io::Result<bool> {
            let buffer = recv(&receive_socket)?;
            if buffer == final_message_server {
                return Ok(false);
            }
            if buffer.starts_with(b"client") {
                return Ok(true);
            }
            let message = receive_secure.verify(&buffer).map_err(themis_as_io_error)?;
            io::stdout().write_all(&message)?;
            Ok(true)
        };
        loop {
            match receive_message() {
                Ok(true) => continue,
                Ok(false) => break,
                Err(e) => {
                    error!("failed to receive message: {}", e);
                    break;
                }
            }
        }
    });

    let relay = thread::spawn(move || {
        let relay_message = || -> io::Result<bool> {
            let mut buffer = String::new();
            io::stdin().read_line(&mut buffer)?;
            if buffer.is_empty() {
                return Ok(false);
            }
            let message = relay_secure.sign(&buffer).map_err(themis_as_io_error)?;
            relay_socket.send(&message)?;
            Ok(true)
        };
        loop {
            match relay_message() {
                Ok(true) => continue,
                Ok(false) => break,
                Err(e) => {
                    error!("failed to relay message: {}", e);
                    break;
                }
            }
        }
        relay_socket
            .send(&final_message_client)
            .expect("final message");
    });

    receive.join().unwrap();
    relay.join().unwrap();
}

fn read_file(path: &str) -> io::Result<Vec<u8>> {
    let mut file = File::open(path)?;
    let mut content = Vec::new();
    file.read_to_end(&mut content)?;
    Ok(content)
}

fn recv(socket: &UdpSocket) -> io::Result<Vec<u8>> {
    let mut message = vec![0; 65536];
    let length = socket.recv(&mut message)?;
    message.truncate(length);
    Ok(message)
}

fn themis_as_io_error(e: themis::Error) -> io::Error {
    io::Error::new(io::ErrorKind::Other, e)
}