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transmitic_stream.rs
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transmitic_stream.rs
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use std::{
error::Error,
io::{Read, Write},
net::TcpStream,
thread, time,
};
use rand_core::OsRng;
use ring::signature;
use x25519_dalek::{EphemeralSecret, PublicKey};
use crate::{
app_aggregator::ExitCodes,
config::SharedUser,
core_consts::{DENIED_SLEEP, TRAN_API_MAJOR, TRAN_API_MINOR, TRAN_MAGIC_NUMBER},
crypto,
encrypted_stream::EncryptedStream,
outgoing_downloader::ERR_REMOTE_ID_NOT_FOUND,
};
const BUFFER_SIZE: usize = 32 + 64;
// TODO drop struct and just use functions instead?
pub struct TransmiticStream {
stream: TcpStream,
connecting_ip: String,
shared_users: Vec<SharedUser>,
private_key_pair: signature::Ed25519KeyPair,
private_id_bytes: Vec<u8>,
matched_shared_user: Option<SharedUser>,
}
impl TransmiticStream {
pub fn new(
stream: TcpStream,
connecting_ip: String,
shared_users: Vec<SharedUser>,
private_id_bytes: Vec<u8>,
) -> TransmiticStream {
// TODO function
let private_key_pair =
signature::Ed25519KeyPair::from_pkcs8(private_id_bytes.as_ref()).unwrap();
stream.set_nonblocking(false).unwrap();
TransmiticStream {
stream,
connecting_ip,
shared_users,
private_key_pair,
private_id_bytes,
matched_shared_user: None,
}
}
pub fn connect(&mut self) -> Result<EncryptedStream, Box<dyn Error>> {
self.send_transmitic_header()?;
self.receive_transmitic_header()?;
let local_diffie_secret = self.send_diffie_helman_key()?;
let remote_diffie_key = self.receive_diffie_helman_key()?;
let encryption_key = self.get_encryption_key(local_diffie_secret, remote_diffie_key);
let encrypted_stream = self.get_encrypted_stream(encryption_key)?;
Ok(encrypted_stream)
}
pub fn wait_for_incoming(&mut self) -> Result<EncryptedStream, Box<dyn Error>> {
self.receive_transmitic_header()?;
self.send_transmitic_header()?;
let remote_diffie_key = self.receive_diffie_helman_key()?;
let local_diffie_secret = self.send_diffie_helman_key()?;
let encryption_key = self.get_encryption_key(local_diffie_secret, remote_diffie_key);
let encrypted_stream = self.get_encrypted_stream(encryption_key)?;
Ok(encrypted_stream)
}
fn get_encrypted_stream(
&self,
encryption_key: [u8; 32],
) -> Result<EncryptedStream, Box<dyn Error>> {
// TODO can i shutdown the original stream?
let cloned_stream = self.stream.try_clone()?;
let shared_user = match &self.matched_shared_user {
Some(shared_user) => shared_user.to_owned(),
None => {
eprintln!("SharedUser not matched for encryption stream");
std::process::exit(ExitCodes::EncStreamNoUser as i32);
}
};
let encrypted_stream = EncryptedStream::new(
cloned_stream,
encryption_key,
shared_user,
self.private_id_bytes.clone(),
);
Ok(encrypted_stream)
}
fn send_transmitic_header(&mut self) -> Result<(), Box<dyn Error>> {
let mut buffer = self.get_header_buffer();
buffer[0..4].copy_from_slice(&TRAN_MAGIC_NUMBER);
buffer[4..6].copy_from_slice(&TRAN_API_MAJOR.to_be_bytes());
buffer[6..8].copy_from_slice(&TRAN_API_MINOR.to_be_bytes());
self.stream.write_all(&buffer)?;
Ok(())
}
fn receive_transmitic_header(&mut self) -> Result<(), Box<dyn Error>> {
let mut buffer = self.get_header_buffer();
// TODO set read timeout
self.stream.read_exact(&mut buffer)?;
if buffer[0..4] != TRAN_MAGIC_NUMBER {
return Err(format!(
"{} TRAN MAGIC NUMBER mismatch. {:?}",
self.connecting_ip,
&buffer[0..4]
)
.into());
}
let api_major: u16 = u16::from_be_bytes(buffer[4..6].try_into().unwrap());
if api_major != TRAN_API_MAJOR {
return Err(format!(
"{} TRAN API MAJOR mismatch. {:?}",
self.connecting_ip, &api_major
)
.into());
}
Ok(())
}
fn get_header_buffer(&self) -> [u8; 8] {
let buffer: [u8; 8] = [0; TRAN_MAGIC_NUMBER.len() + 2 + 2];
buffer
}
fn send_diffie_helman_key(&mut self) -> Result<EphemeralSecret, Box<dyn Error>> {
let local_diffie_secret = EphemeralSecret::random_from_rng(OsRng);
let local_diffie_public = PublicKey::from(&local_diffie_secret);
let local_diffie_public_bytes: &[u8; 32] = local_diffie_public.as_bytes();
let local_diffie_signature_public_bytes =
self.private_key_pair.sign(local_diffie_public_bytes);
let local_diffie_signed_public_bytes = local_diffie_signature_public_bytes.as_ref();
// diffie public key + diffie public key signed
let mut buffer = [0; BUFFER_SIZE];
buffer[0..32].copy_from_slice(&local_diffie_public_bytes[0..32]);
buffer[32..BUFFER_SIZE].copy_from_slice(&local_diffie_signed_public_bytes[0..64]);
self.stream.write_all(&buffer)?;
Ok(local_diffie_secret)
}
fn receive_diffie_helman_key(&mut self) -> Result<x25519_dalek::PublicKey, Box<dyn Error>> {
let mut buffer: [u8; BUFFER_SIZE] = [0; BUFFER_SIZE];
// TODO set read timeout
self.stream.read_exact(&mut buffer)?;
// Get diffie bytes from buffer
let mut remote_diffie_public_bytes: [u8; 32] = [0; 32];
remote_diffie_public_bytes.copy_from_slice(&buffer[0..32]);
// Get signed diffie bytes from buffer
let mut remote_diffie_signed_public_bytes: [u8; 64] = [0; 64];
remote_diffie_signed_public_bytes[..].copy_from_slice(&buffer[32..BUFFER_SIZE]);
// Try every shared user
for shared_user in &self.shared_users {
// Load PublicID from shared_user
let remote_public_id_bytes = crypto::get_bytes_from_base64_str(&shared_user.public_id)?;
let remote_public_key =
signature::UnparsedPublicKey::new(&signature::ED25519, remote_public_id_bytes);
// Verify diffie bytes were signed with the PublicID we have for this user
if remote_public_key
.verify(
&remote_diffie_public_bytes,
&remote_diffie_signed_public_bytes,
)
.is_ok()
{
// Found SharedUser
self.matched_shared_user = Some(shared_user.to_owned());
break;
}
}
// No SharedUser could be found. This is an unknown user.
if self.matched_shared_user.is_none() {
thread::sleep(time::Duration::from_secs(DENIED_SLEEP));
return Err(ERR_REMOTE_ID_NOT_FOUND.to_string().into());
}
// Create the diffie public key now that it's been verified
let remote_diffie_public_key = PublicKey::from(remote_diffie_public_bytes);
Ok(remote_diffie_public_key)
}
fn get_encryption_key(
&self,
local_diffie_secret: EphemeralSecret,
remote_diffie_public_key: PublicKey,
) -> [u8; 32] {
let local_shared_secret = local_diffie_secret.diffie_hellman(&remote_diffie_public_key);
let encryption_key = local_shared_secret.as_bytes();
*encryption_key
}
}