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//!
//! Roughtime server
//!
extern crate byteorder;
extern crate core;
extern crate ring;
extern crate roughenough;
extern crate time;
extern crate untrusted;
use std::io;
use std::net::UdpSocket;
use std::time::Duration;
use untrusted::Input;
use roughenough::{RtMessage, Tag, Error};
use roughenough::hex::*;
use roughenough::{CERTIFICATE_CONTEXT, SIGNED_RESPONSE_CONTEXT, TREE_LEAF_TWEAK};
use ring::{digest, error, rand};
use ring::rand::SecureRandom;
use ring::signature::Ed25519KeyPair;
use byteorder::{LittleEndian, WriteBytesExt};
fn get_long_term_key() -> Result<Ed25519KeyPair, error::Unspecified> {
// TODO: read from config
let seed = [b'x'; 32];
Ed25519KeyPair::from_seed_unchecked(Input::from(&seed))
}
fn make_ephemeral_key() -> Result<Ed25519KeyPair, error::Unspecified> {
let rng = rand::SystemRandom::new();
let mut seed = [0u8; 32];
rng.fill(&mut seed).unwrap();
Ed25519KeyPair::from_seed_unchecked(Input::from(&seed))
}
fn make_dele_bytes(ephemeral_key: &Ed25519KeyPair) -> Result<Vec<u8>, Error> {
let zeros = [0u8; 8];
let max = [0xff; 8];
let mut dele_msg = RtMessage::new(3);
dele_msg.add_field(Tag::PUBK, &ephemeral_key.public_key_bytes())?;
dele_msg.add_field(Tag::MINT, &zeros)?;
dele_msg.add_field(Tag::MAXT, &max)?;
dele_msg.encode()
}
fn make_cert(long_term_key: &Ed25519KeyPair, ephemeral_key: &Ed25519KeyPair) -> RtMessage {
// Make DELE and sign it with long-term key
let dele_bytes = make_dele_bytes(&ephemeral_key).unwrap();
let dele_sig = {
let mut sha_ctx = digest::Context::new(&digest::SHA512);
sha_ctx.update(CERTIFICATE_CONTEXT.as_bytes());
sha_ctx.update(&dele_bytes);
let digest = sha_ctx.finish();
long_term_key.sign(digest.as_ref())
};
// Create CERT
let mut cert_msg = RtMessage::new(2);
cert_msg.add_field(Tag::SIG, dele_sig.as_ref()).unwrap();
cert_msg.add_field(Tag::DELE, &dele_bytes).unwrap();
cert_msg
}
fn make_response(ephemeral_key: &Ed25519KeyPair, cert_bytes: &[u8], request: &[u8]) -> RtMessage {
// create SREP
// sign SREP
// create response:
// - SIG
// - PATH (always 0)
// - SREP
// - CERT (pre-created)
// - INDX (always 0)
let path = [0u8; 0];
let zeros = [0u8; 4];
let mut radi: Vec<u8> = Vec::with_capacity(4);
let mut midp: Vec<u8> = Vec::with_capacity(8);
// TODO: populate
let mut nonce = vec![0u8; 64];
// one second (in microseconds)
radi.write_u32::<LittleEndian>(1000000).unwrap();
// current epoch time in microseconds
let now = (time::get_time().sec as u64) * 1000;
midp.write_u64::<LittleEndian>(now).unwrap();
// Signed response SREP
let srep_bytes = {
// hash request nonce
let mut ctx = digest::Context::new(&digest::SHA512);
ctx.update(&TREE_LEAF_TWEAK);
ctx.update(&nonce);
let digest = ctx.finish();
let mut srep_msg = RtMessage::new(3);
srep_msg.add_field(Tag::RADI, &radi).unwrap();
srep_msg.add_field(Tag::MIDP, &midp).unwrap();
srep_msg.add_field(Tag::ROOT, digest.as_ref()).unwrap();
srep_msg.encode().unwrap()
};
// signature on SREP
let signature = {
let mut sha_ctx = digest::Context::new(&digest::SHA512);
sha_ctx.update(SIGNED_RESPONSE_CONTEXT.as_bytes());
sha_ctx.update(&srep_bytes);
let digest = sha_ctx.finish();
ephemeral_key.sign(digest.as_ref())
};
let mut response = RtMessage::new(5);
response.add_field(Tag::SIG, signature.as_ref()).unwrap();
response.add_field(Tag::PATH, &path).unwrap();
response.add_field(Tag::SREP, &srep_bytes).unwrap();
response.add_field(Tag::CERT, cert_bytes).unwrap();
response.add_field(Tag::INDX, &zeros).unwrap();
response
}
fn main() {
let lt_key = get_long_term_key().expect("failed to obtain long-term key");
let ephemeral_key = make_ephemeral_key().expect("failed to create ephemeral key");
println!("Long-term public key: {}", lt_key.public_key_bytes().to_hex());
println!("Ephemeral public key: {}", ephemeral_key.public_key_bytes().to_hex());
let cert_msg = make_cert(<_key, &ephemeral_key);
let cert_bytes = cert_msg.encode().unwrap();
let mut socket = UdpSocket::bind("127.0.0.1:8686").expect("failed to bind to socket");
socket.set_read_timeout(Some(Duration::from_secs(1))).expect("could not set read timeout");
let mut buf = [0u8; 65536];
let mut loops = 0u64;
loop {
match socket.recv_from(&mut buf) {
Ok((num_bytes, src_addr)) => {
println!("{} bytes from {}", num_bytes, src_addr);
let resp = make_response(&ephemeral_key, &cert_bytes, &buf[..num_bytes]);
println!("response {:?}", resp.encode().unwrap().to_hex());
},
Err(ref e) if e.kind() == io::ErrorKind::WouldBlock => loops += 1,
Err(ref e) => println!("Error {:?}: {:?}", e.kind(), e)
}
}
// loop:
// read request
// validate request or goto loop
// send response
}
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