Add secret updating after key exchange

Signed-off-by: trivernis <trivernis@protonmail.com>
pull/1/head
trivernis 4 years ago
parent 34a1fd2cf0
commit 394e2bb68e
Signed by: Trivernis
GPG Key ID: DFFFCC2C7A02DB45

@ -1,7 +1,7 @@
[package]
name = "vented"
description = "Event driven encrypted tcp communicaton"
version = "0.1.3"
version = "0.2.0"
authors = ["trivernis <trivernis@protonmail.com>"]
edition = "2018"
readme = "README.md"

@ -1,6 +1,5 @@
use std::io::{Read, Write};
use std::net::TcpStream;
use std::sync::atomic::{AtomicUsize, Ordering};
use std::sync::Arc;
use byteorder::{BigEndian, ByteOrder};
@ -13,6 +12,7 @@ use typenum::U24;
use crate::event::Event;
use crate::result::VentedResult;
use crypto_box::ChaChaBox;
pub use crypto_box::PublicKey;
pub use crypto_box::SecretKey;
@ -21,24 +21,28 @@ pub use crypto_box::SecretKey;
pub struct CryptoStream {
send_stream: Arc<Mutex<TcpStream>>,
recv_stream: Arc<Mutex<TcpStream>>,
sent_count: Arc<AtomicUsize>,
recv_count: Arc<AtomicUsize>,
secret_box: Arc<Mutex<crypto_box::ChaChaBox>>,
send_secret: Arc<Mutex<EncryptionBox<ChaChaBox>>>,
recv_secret: Arc<Mutex<EncryptionBox<ChaChaBox>>>,
}
impl CryptoStream {
/// Creates a new crypto stream from a given Tcp Stream and with a given secret
pub fn new(inner: TcpStream, secret_box: crypto_box::ChaChaBox) -> VentedResult<Self> {
pub fn new(
inner: TcpStream,
public_key: &PublicKey,
secret_key: &SecretKey,
) -> VentedResult<Self> {
inner.set_nonblocking(false)?;
let send_stream = Arc::new(Mutex::new(inner.try_clone()?));
let recv_stream = Arc::new(Mutex::new(inner));
let send_box = EncryptionBox::new(ChaChaBox::new(public_key, secret_key));
let recv_box = EncryptionBox::new(ChaChaBox::new(public_key, secret_key));
Ok(Self {
send_stream,
recv_stream,
sent_count: Arc::new(AtomicUsize::new(0)),
recv_count: Arc::new(AtomicUsize::new(0)),
secret_box: Arc::new(Mutex::new(secret_box)),
send_secret: Arc::new(Mutex::new(send_box)),
recv_secret: Arc::new(Mutex::new(recv_box)),
})
}
@ -47,16 +51,7 @@ impl CryptoStream {
/// length: u64
/// data: length
pub fn send(&self, mut event: Event) -> VentedResult<()> {
let number = self.sent_count.fetch_add(1, Ordering::SeqCst);
let nonce = generate_nonce(number);
let ciphertext = self.secret_box.lock().encrypt(
&nonce,
Payload {
msg: &event.as_bytes(),
aad: &[],
},
)?;
let ciphertext = self.send_secret.lock().encrypt(&event.as_bytes())?;
let mut stream = self.send_stream.lock();
let mut length_raw = [0u8; 8];
BigEndian::write_u64(&mut length_raw, ciphertext.len() as u64);
@ -83,20 +78,78 @@ impl CryptoStream {
stream.read(&mut ciphertext)?;
log::trace!("Received raw message");
let number = self.recv_count.fetch_add(1, Ordering::SeqCst);
let nonce = generate_nonce(number);
let plaintext = self.secret_box.lock().decrypt(
let plaintext = self.recv_secret.lock().decrypt(&ciphertext)?;
let event = Event::from_bytes(&mut &plaintext[..])?;
log::trace!("Decoded message to event '{}'", event.name);
Ok(event)
}
/// Updates the keys in the inner encryption box
pub fn update_key(&self, secret_key: &SecretKey, public_key: &PublicKey) {
let send_box = ChaChaBox::new(public_key, secret_key);
let recv_box = ChaChaBox::new(public_key, secret_key);
self.send_secret.lock().swap_box(send_box);
self.recv_secret.lock().swap_box(recv_box);
log::trace!("Updated secret");
}
}
pub struct EncryptionBox<T>
where
T: Aead,
{
inner: T,
counter: usize,
}
impl<T> EncryptionBox<T>
where
T: Aead,
{
/// Creates a new encryption box with the given inner value
pub fn new(inner: T) -> Self {
Self { inner, counter: 0 }
}
/// Swaps the crypto box for a new one
pub fn swap_box(&mut self, new_box: T) {
self.inner = new_box;
}
}
impl EncryptionBox<ChaChaBox> {
/// Encrypts the given data by using the inner ChaCha box and nonce
pub fn encrypt(&mut self, data: &[u8]) -> VentedResult<Vec<u8>> {
let nonce = generate_nonce(self.counter);
let ciphertext = self.inner.encrypt(
&nonce,
Payload {
msg: &ciphertext,
aad: &[],
msg: data,
},
)?;
self.counter += 1;
let event = Event::from_bytes(&mut &plaintext[..])?;
log::trace!("Decoded message to event '{}'", event.name);
Ok(ciphertext)
}
Ok(event)
/// Decrypts the data by using the inner ChaCha box and nonce
pub fn decrypt(&mut self, data: &[u8]) -> VentedResult<Vec<u8>> {
let nonce = generate_nonce(self.counter);
let plaintext = self.inner.decrypt(
&nonce,
Payload {
msg: data,
aad: &[],
},
)?;
self.counter += 1;
Ok(plaintext)
}
}

@ -1,7 +1,7 @@
use std::collections::HashMap;
use std::net::{TcpListener, TcpStream};
use crypto_box::{ChaChaBox, PublicKey, SecretKey};
use crypto_box::{PublicKey, SecretKey};
use scheduled_thread_pool::ScheduledThreadPool;
use crate::crypto::CryptoStream;
@ -16,6 +16,7 @@ use crate::server::server_events::{
};
use crossbeam_utils::sync::WaitGroup;
use parking_lot::Mutex;
use sha2::Digest;
use std::io::Write;
use std::sync::Arc;
use std::thread;
@ -327,7 +328,6 @@ impl VentedServer {
}
let public_key = PublicKey::from(public_key);
let secret_box = ChaChaBox::new(&public_key, &secret_key);
let node_data = if let Some(data) = known_nodes.lock().iter().find(|n| n.id == node_id) {
data.clone()
@ -337,14 +337,21 @@ impl VentedServer {
return Err(UnknownNode(node_id));
};
let mut stream = CryptoStream::new(stream, secret_box)?;
let mut stream = CryptoStream::new(stream, &public_key, &secret_key)?;
log::trace!("Authenticating recipient...");
Self::authenticate_other(&mut stream, node_data.public_key)?;
let key_a = Self::authenticate_other(&mut stream, node_data.public_key)?;
log::trace!("Authenticating self...");
let key_b =
Self::authenticate_self(&mut stream, StaticSecret::from(global_secret.to_bytes()))?;
log::trace!("Connection fully authenticated.");
let pre_secret = StaticSecret::from(secret_key.to_bytes()).diffie_hellman(&public_key);
let final_secret =
Self::generate_final_secret(pre_secret.to_bytes().to_vec(), key_a, key_b);
let final_public = final_secret.public_key();
stream.update_key(&final_secret, &final_public);
Ok((node_id, stream))
}
@ -400,20 +407,30 @@ impl VentedServer {
.as_bytes(),
)?;
stream.flush()?;
let secret_box = ChaChaBox::new(&public_key, &secret_key);
let mut stream = CryptoStream::new(stream, secret_box)?;
let mut stream = CryptoStream::new(stream, &public_key, &secret_key)?;
log::trace!("Authenticating self...");
let key_a =
Self::authenticate_self(&mut stream, StaticSecret::from(global_secret.to_bytes()))?;
log::trace!("Authenticating recipient...");
Self::authenticate_other(&mut stream, node_data.public_key)?;
let key_b = Self::authenticate_other(&mut stream, node_data.public_key)?;
log::trace!("Connection fully authenticated.");
let pre_secret = StaticSecret::from(secret_key.to_bytes()).diffie_hellman(&public_key);
let final_secret =
Self::generate_final_secret(pre_secret.to_bytes().to_vec(), key_a, key_b);
let final_public = final_secret.public_key();
stream.update_key(&final_secret, &final_public);
Ok((node_id, stream))
}
/// Performs the challenged side of the authentication challenge
fn authenticate_self(stream: &CryptoStream, static_secret: StaticSecret) -> VentedResult<()> {
fn authenticate_self(
stream: &CryptoStream,
static_secret: StaticSecret,
) -> VentedResult<Vec<u8>> {
let challenge_event = stream.read()?;
if challenge_event.name != CHALLENGE_EVENT {
@ -433,7 +450,7 @@ impl VentedServer {
let response = stream.read()?;
match response.name.as_str() {
ACCEPT_EVENT => Ok(()),
ACCEPT_EVENT => Ok(auth_key.to_bytes().to_vec()),
REJECT_EVENT => Err(VentedError::Rejected),
_ => {
stream.send(Event::new(REJECT_EVENT))?;
@ -446,7 +463,7 @@ impl VentedServer {
fn authenticate_other(
stream: &CryptoStream,
other_static_public: PublicKey,
) -> VentedResult<()> {
) -> VentedResult<Vec<u8>> {
let auth_secret = SecretKey::generate(&mut rand::thread_rng());
stream.send(Event::with_payload(
CHALLENGE_EVENT,
@ -470,7 +487,7 @@ impl VentedServer {
Err(VentedError::AuthFailed)
} else {
stream.send(Event::new(ACCEPT_EVENT))?;
Ok(())
Ok(calculated_secret.to_vec())
}
}
@ -481,4 +498,21 @@ impl VentedServer {
parts_a.get(0) == parts_b.get(0) && parts_a.get(1) == parts_b.get(1)
}
/// Generates a secret from handshake components
fn generate_final_secret(
mut pre_secret: Vec<u8>,
mut key_a: Vec<u8>,
mut key_b: Vec<u8>,
) -> SecretKey {
let mut secret_data = Vec::new();
secret_data.append(&mut pre_secret);
secret_data.append(&mut key_a);
secret_data.append(&mut key_b);
let final_secret = sha2::Sha256::digest(&secret_data).to_vec();
let mut final_secret_arr = [0u8; 32];
final_secret_arr.copy_from_slice(&final_secret[..]);
SecretKey::from(final_secret_arr)
}
}

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