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/* SPDX-License-Identifier: GPL-2.0
*
* Copyright (C) 2017-2019 WireGuard LLC. All Rights Reserved.
*/
#![allow(unused)]
use consts::COOKIE_REFRESH_TIME;
use message::CookieReply;
use xchacha20poly1305;
use blake2_rfc::blake2s::{blake2s, Blake2sResult};
use failure::{Error, err_msg};
use hex;
use rand::{self, RngCore};
use subtle::ConstantTimeEq;
use std::time::Instant;
pub struct ValidatorMac2 {
secret: [u8; 16],
secret_time: Option<Instant>,
key: Blake2sResult,
}
pub struct GeneratorMac2 {
cookie: [u8; 16],
cookie_time: Option<Instant>,
last_mac1: Option<Blake2sResult>,
key: Blake2sResult,
}
pub struct Validator {
mac1_key: Blake2sResult,
mac2: ValidatorMac2
}
pub struct Generator {
mac1_key: Blake2sResult,
mac2: GeneratorMac2,
}
impl Validator {
pub fn new(pub_key: &[u8]) -> Self {
let mac1_key = blake2s(32, &[], &[b"mac1----", pub_key].concat());
let mac2_key = blake2s(32, &[], &[b"cookie--", pub_key].concat());
Self {
mac1_key,
mac2: ValidatorMac2 {
secret: [0u8; 16],
secret_time: None,
key: mac2_key,
}
}
}
pub fn verify_mac1(&self, mac_input: &[u8], mac: &[u8]) -> Result<(), Error> {
debug_assert!(mac.len() == 16);
let our_mac = blake2s(16, self.mac1_key.as_bytes(), mac_input);
ensure!(mac.ct_eq(our_mac.as_bytes()).unwrap_u8() == 1, "mac mismatch");
Ok(())
}
pub fn verify_mac2(&self, message: &[u8], source: &[u8]) -> Result<(), Error> {
let secret_time = self.mac2.secret_time.ok_or_else(|| err_msg("no mac2 secret time set"))?;
ensure!(Instant::now().duration_since(secret_time) <= *COOKIE_REFRESH_TIME, "secret is too old");
let cookie = blake2s(16, &self.mac2.secret, source);
let mac2 = blake2s(16, cookie.as_bytes(), &message[..message.len()-16]);
let our_mac2 = mac2.as_bytes();
let thr_mac2 = &message[message.len()-16..];
if our_mac2.ct_eq(&thr_mac2).unwrap_u8() != 1 {
trace!("mac mismatch, ours: {:?}", hex::encode(our_mac2));
trace!("mac mismatch, thrs: {:?}", hex::encode(thr_mac2));
bail!("mac mismatch")
}
Ok(())
}
// TODO: is this the right scope - should Validator really know how to form packets?
pub fn generate_reply(&mut self, sender: u32, mac1: &[u8], source: &[u8]) -> Result<CookieReply, Error> {
let mut rng = rand::thread_rng();
let mut reply = CookieReply::new();
reply.set_receiver_index(sender);
// refresh cookie secret
if !is_secret_valid(self.mac2.secret_time) {
rng.fill_bytes(&mut self.mac2.secret);
self.mac2.secret_time = Some(Instant::now());
}
// derive cookie
let input = blake2s(16, &self.mac2.secret, source);
// encrypt cookie
{
let (nonce, cookie) = reply.nonce_cookie_mut();
rng.fill_bytes(nonce);
let tag = xchacha20poly1305::encrypt(self.mac2.key.as_bytes(), nonce, input.as_bytes(), mac1, &mut cookie[..16])?;
cookie[16..].copy_from_slice(&tag);
}
Ok(reply)
}
}
impl Generator {
pub fn new(pub_key: &[u8]) -> Self {
let mac1_key = blake2s(32, &[], &[b"mac1----", pub_key].concat());
let mac2_key = blake2s(32, &[], &[b"cookie--", pub_key].concat());
Self {
mac1_key,
mac2: GeneratorMac2 {
cookie: [0u8; 16],
cookie_time: None,
last_mac1: None,
key: mac2_key,
}
}
}
pub fn consume_reply(&mut self, reply: &CookieReply) -> Result<(), Error> {
let last_mac1 = self.mac2.last_mac1.ok_or_else(|| err_msg("no last mac1"))?;
xchacha20poly1305::decrypt(self.mac2.key.as_bytes(),
reply.nonce(),
reply.cookie(),
last_mac1.as_bytes(),
reply.aead_tag(),
&mut self.mac2.cookie)?;
self.mac2.cookie_time = Some(Instant::now());
Ok(())
}
pub fn build_macs(&mut self, input: &[u8]) -> (Blake2sResult, Option<Blake2sResult>) {
let mac1 = blake2s(16, self.mac1_key.as_bytes(), input);
let mac2 = if is_secret_valid(self.mac2.cookie_time) {
Some(blake2s(16, &self.mac2.cookie, &[input, mac1.as_bytes()].concat()))
} else {
None
};
self.mac2.last_mac1 = Some(mac1);
(mac1, mac2)
}
}
fn is_secret_valid(secret_time: Option<Instant>) -> bool {
if let Some(time) = secret_time {
Instant::now().duration_since(time) <= *COOKIE_REFRESH_TIME
} else {
false
}
}
#[test]
fn sanity() {
}
|
