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vpncloud/src/beacon.rs

460 lines
17 KiB

// VpnCloud - Peer-to-Peer VPN
// Copyright (C) 2015-2021 Dennis Schwerdel
// This software is licensed under GPL-3 or newer (see LICENSE.md)
use ring::digest;
use std::{
fs::{self, File, Permissions},
io::{self, Read, Write},
marker::PhantomData,
mem,
num::Wrapping,
os::unix::fs::PermissionsExt,
path::Path,
process::{Command, Stdio},
sync::{
atomic::{AtomicBool, Ordering},
Arc, Mutex,
},
thread,
};
use super::util::{from_base62, to_base62, Encoder, TimeSource};
use smallvec::SmallVec;
use std::net::{Ipv4Addr, Ipv6Addr, SocketAddr, SocketAddrV4, SocketAddrV6};
const TYPE_BEGIN: u8 = 0;
const TYPE_END: u8 = 1;
const TYPE_DATA: u8 = 2;
const TYPE_SEED: u8 = 3;
fn base_62_sanitize(data: &str) -> String {
data.chars().filter(|c| c.is_ascii_alphanumeric()).collect()
}
fn sha512(data: &[u8]) -> SmallVec<[u8; 64]> {
digest::digest(&digest::SHA512, data).as_ref().into()
}
struct FutureResult<T> {
has_result: AtomicBool,
result: Mutex<T>,
}
#[derive(Clone)]
pub struct BeaconSerializer<TS> {
shared_key: Vec<u8>,
future_peers: Arc<FutureResult<Vec<SocketAddr>>>,
_dummy_ts: PhantomData<TS>,
}
impl<TS: TimeSource> BeaconSerializer<TS> {
pub fn new(shared_key: &[u8]) -> Self {
Self {
shared_key: shared_key.to_owned(),
future_peers: Arc::new(FutureResult { has_result: AtomicBool::new(false), result: Mutex::new(Vec::new()) }),
_dummy_ts: PhantomData,
}
}
fn now_hour_16() -> u16 {
((TS::now() / 3600) & 0xffff) as u16
}
fn get_keystream(&self, type_: u8, seed: u8, iter: u8) -> SmallVec<[u8; 64]> {
let mut data = SmallVec::<[u8; 128]>::new();
data.extend_from_slice(&[type_, seed, iter]);
data.extend_from_slice(&self.shared_key);
sha512(&data)
}
#[allow(clippy::needless_range_loop)]
fn mask_with_keystream(&self, data: &mut [u8], type_: u8, seed: u8) {
let mut iter = 0;
let mut mask = self.get_keystream(type_, seed, iter);
let mut pos = 0;
for i in 0..data.len() {
data[i] ^= mask[pos];
pos += 1;
if pos == 16 {
pos = 0;
iter += 1;
mask = self.get_keystream(type_, seed, iter);
}
}
}
fn begin(&self) -> String {
to_base62(&self.get_keystream(TYPE_BEGIN, 0, 0))[0..5].to_string()
}
fn end(&self) -> String {
to_base62(&self.get_keystream(TYPE_END, 0, 0))[0..5].to_string()
}
fn encrypt_data(&self, data: &mut Vec<u8>) {
// Note: the 1 byte seed is only meant to protect from random changes,
// not malicious ones. For full protection, at least 8 bytes (~12
// characters) would be needed.
let seed = sha512(data as &[u8])[0];
self.mask_with_keystream(data as &mut [u8], TYPE_DATA, seed);
data.push(seed ^ self.get_keystream(TYPE_SEED, 0, 0)[0]);
}
fn decrypt_data(&self, data: &mut Vec<u8>) -> bool {
if data.is_empty() {
return false;
}
let seed = data.pop().unwrap() ^ self.get_keystream(TYPE_SEED, 0, 0)[0];
self.mask_with_keystream(data as &mut [u8], TYPE_DATA, seed);
seed == sha512(data as &[u8])[0]
}
fn peerlist_encode(&self, peers: &[SocketAddr]) -> String {
let mut data = Vec::new();
// Add timestamp
data.extend_from_slice(&Self::now_hour_16().to_be_bytes());
// Split addresses into v4 and v6
let mut v4addrs = SmallVec::<[SocketAddrV4; 256]>::new();
let mut v6addrs = SmallVec::<[SocketAddrV6; 256]>::new();
for p in peers {
match *p {
SocketAddr::V4(addr) => v4addrs.push(addr),
SocketAddr::V6(addr) => v6addrs.push(addr),
}
}
// Add count of v4 addresses
data.push(v4addrs.len() as u8);
// Add v4 addresses
for addr in v4addrs {
let mut dat = [0u8; 6];
dat[0..4].copy_from_slice(&addr.ip().octets());
Encoder::write_u16(addr.port(), &mut dat[4..]);
data.extend_from_slice(&dat);
}
// Add v6 addresses
for addr in v6addrs {
let mut dat = [0u8; 18];
let ip = addr.ip().segments();
Encoder::write_u16(ip[0], &mut dat[0..]);
Encoder::write_u16(ip[1], &mut dat[2..]);
Encoder::write_u16(ip[2], &mut dat[4..]);
Encoder::write_u16(ip[3], &mut dat[6..]);
Encoder::write_u16(ip[4], &mut dat[8..]);
Encoder::write_u16(ip[5], &mut dat[10..]);
Encoder::write_u16(ip[6], &mut dat[12..]);
Encoder::write_u16(ip[7], &mut dat[14..]);
Encoder::write_u16(addr.port(), &mut dat[16..]);
data.extend_from_slice(&dat);
}
self.encrypt_data(&mut data);
to_base62(&data)
}
fn peerlist_decode(&self, data: &str, ttl_hours: Option<u16>) -> Vec<SocketAddr> {
let mut data = from_base62(data).expect("Invalid input");
let mut peers = Vec::new();
let mut pos = 0;
if data.len() < 4 {
return peers;
}
if !self.decrypt_data(&mut data) {
return peers;
}
let then = Wrapping(Encoder::read_u16(&data[pos..=pos + 1]));
if let Some(ttl) = ttl_hours {
let now = Wrapping(Self::now_hour_16());
if now - then > Wrapping(ttl) && then - now > Wrapping(ttl) {
return peers;
}
}
pos += 2;
let v4count = data[pos] as usize;
pos += 1;
if v4count * 6 > data.len() - pos || (data.len() - pos - v4count * 6) % 18 > 0 {
return peers;
}
for _ in 0..v4count {
assert!(data.len() >= pos + 6);
let dat = &data[pos..pos + 6];
pos += 6;
let port = Encoder::read_u16(&dat[4..]);
let addr = SocketAddr::V4(SocketAddrV4::new(Ipv4Addr::new(dat[0], dat[1], dat[2], dat[3]), port));
peers.push(addr);
}
let v6count = (data.len() - pos) / 18;
for _ in 0..v6count {
assert!(data.len() >= pos + 18);
let dat = &data[pos..pos + 18];
pos += 18;
let mut ip = [0u16; 8];
for i in 0..8 {
ip[i] = Encoder::read_u16(&dat[i * 2..i * 2 + 2]);
}
let port = Encoder::read_u16(&dat[16..]);
let addr = SocketAddr::V6(SocketAddrV6::new(
Ipv6Addr::new(ip[0], ip[1], ip[2], ip[3], ip[4], ip[5], ip[6], ip[7]),
port,
0,
0,
));
peers.push(addr);
}
peers
}
pub fn encode(&self, peers: &[SocketAddr]) -> String {
format!("{}{}{}", self.begin(), self.peerlist_encode(peers), self.end())
}
pub fn write_to_file<P: AsRef<Path>>(&self, peers: &[SocketAddr], path: P) -> Result<(), io::Error> {
let beacon = self.encode(peers);
debug!("Beacon: {}", beacon);
let path = path.as_ref();
if path.exists() {
fs::remove_file(path)?
}
let mut f = File::create(path)?;
writeln!(&mut f, "{}", beacon)?;
fs::set_permissions(path, Permissions::from_mode(0o444))?;
Ok(())
}
pub fn write_to_cmd(&self, peers: &[SocketAddr], cmd: &str) -> Result<(), io::Error> {
let begin = self.begin();
let data = self.peerlist_encode(peers);
let end = self.end();
let beacon = format!("{}{}{}", begin, data, end);
debug!("Calling beacon command: {}", cmd);
let process = Command::new("sh")
.args(&["-c", cmd])
.env("begin", begin)
.env("data", data)
.env("end", end)
.env("beacon", beacon)
.stdout(Stdio::piped())
.stderr(Stdio::piped())
.spawn()?;
thread::spawn(move || {
let output = process.wait_with_output().expect("Failed to wait on child");
if !output.status.success() {
error!("Beacon command failed: {}", String::from_utf8_lossy(&output.stderr));
} else {
debug!("Beacon command succeeded");
}
});
Ok(())
}
pub fn decode(&self, data: &str, ttl_hours: Option<u16>) -> Vec<SocketAddr> {
let data = base_62_sanitize(data);
let mut peers = Vec::new();
let begin = self.begin();
let end = self.end();
let mut pos = 0;
while let Some(found) = data[pos..].find(&begin) {
pos += found;
let start_pos = pos + begin.len();
if let Some(found) = data[pos..].find(&end) {
let end_pos = pos + found;
peers.append(&mut self.peerlist_decode(&data[start_pos..end_pos], ttl_hours));
pos = start_pos
} else {
break;
}
}
peers
}
pub fn read_from_file<P: AsRef<Path>>(
&self, path: P, ttl_hours: Option<u16>,
) -> Result<Vec<SocketAddr>, io::Error> {
let mut f = File::open(&path)?;
let mut contents = String::new();
f.read_to_string(&mut contents)?;
Ok(self.decode(&contents, ttl_hours))
}
pub fn read_from_cmd(&self, cmd: &str, ttl_hours: Option<u16>) -> Result<(), io::Error> {
let begin = self.begin();
let end = self.end();
debug!("Calling beacon command: {}", cmd);
let process = Command::new("sh")
.args(&["-c", cmd])
.env("begin", begin)
.env("end", end)
.stdout(Stdio::piped())
.stderr(Stdio::piped())
.spawn()?;
let this = self.clone();
thread::spawn(move || {
let output = process.wait_with_output().expect("Failed to wait on child");
if output.status.success() {
let data = String::from_utf8_lossy(&output.stdout);
let mut peers = this.decode(&data, ttl_hours);
debug!("Beacon command succeeded with {} peers", peers.len());
mem::swap(&mut peers, &mut this.future_peers.result.lock().expect("Lock poisoned"));
this.future_peers.has_result.store(true, Ordering::Relaxed);
} else {
error!("Beacon command failed: {}", String::from_utf8_lossy(&output.stderr));
}
});
Ok(())
}
pub fn get_cmd_results(&self) -> Option<Vec<SocketAddr>> {
if self.future_peers.has_result.load(Ordering::Relaxed) {
let mut peers = Vec::new();
mem::swap(&mut peers, &mut self.future_peers.result.lock().expect("Lock poisoned"));
self.future_peers.has_result.store(false, Ordering::Relaxed);
Some(peers)
} else {
None
}
}
}
#[cfg(test)]
use crate::util::MockTimeSource;
#[cfg(test)]
use std::str::FromStr;
#[cfg(test)]
use std::time::Duration;
#[test]
fn encode() {
MockTimeSource::set_time(2000 * 3600);
let ser = BeaconSerializer::<MockTimeSource>::new(b"mysecretkey");
let mut peers = vec![SocketAddr::from_str("1.2.3.4:5678").unwrap(), SocketAddr::from_str("6.6.6.6:53").unwrap()];
assert_eq!("WsHI31EWDMBYxvITiILIrm2k9gEik22E", ser.encode(&peers));
peers.push(SocketAddr::from_str("[::1]:5678").unwrap());
assert_eq!("WsHI3GXKaXCveo6uejmZizZ72kR6Y0L9T7h49TXONp1ugfKvvvEik22E", ser.encode(&peers));
let peers = vec![SocketAddr::from_str("1.2.3.4:5678").unwrap(), SocketAddr::from_str("6.6.6.6:54").unwrap()];
assert_eq!("WsHI32gm9eMSHP3Lm1GXcdP7rD3ik22E", ser.encode(&peers));
}
#[test]
fn decode() {
MockTimeSource::set_time(2000 * 3600);
let ser = BeaconSerializer::<MockTimeSource>::new(b"mysecretkey");
let mut peers = vec![SocketAddr::from_str("1.2.3.4:5678").unwrap(), SocketAddr::from_str("6.6.6.6:53").unwrap()];
assert_eq!(format!("{:?}", peers), format!("{:?}", ser.decode("WsHI31EWDMBYxvITiILIrm2k9gEik22E", None)));
peers.push(SocketAddr::from_str("[::1]:5678").unwrap());
assert_eq!(
format!("{:?}", peers),
format!("{:?}", ser.decode("WsHI3GXKaXCveo6uejmZizZ72kR6Y0L9T7h49TXONp1ugfKvvvEik22E", None))
);
}
#[test]
fn decode_split() {
MockTimeSource::set_time(2000 * 3600);
let ser = BeaconSerializer::<MockTimeSource>::new(b"mysecretkey");
let peers = vec![SocketAddr::from_str("1.2.3.4:5678").unwrap(), SocketAddr::from_str("6.6.6.6:53").unwrap()];
assert_eq!(
format!("{:?}", peers),
format!("{:?}", ser.decode("WsHI3-1E.WD:MB Yx\tvI\nTi(IL)Ir[m2]k9ügEäik22E", None))
);
assert_eq!(
format!("{:?}", peers),
format!("{:?}", ser.decode("W -, \nsH--I31EWDMBYxvITiILIrm2k9gEi(k)2ÖÄÜ\n2E", None))
);
}
#[test]
fn decode_offset() {
MockTimeSource::set_time(2000 * 3600);
let ser = BeaconSerializer::<MockTimeSource>::new(b"mysecretkey");
let peers = vec![SocketAddr::from_str("1.2.3.4:5678").unwrap(), SocketAddr::from_str("6.6.6.6:53").unwrap()];
assert_eq!(
format!("{:?}", peers),
format!("{:?}", ser.decode("Hello World: WsHI31EWDMBYxvITiILIrm2k9gEik22E! End of the World", None))
);
}
#[test]
fn decode_multiple() {
MockTimeSource::set_time(2000 * 3600);
let ser = BeaconSerializer::<MockTimeSource>::new(b"mysecretkey");
let peers = vec![SocketAddr::from_str("1.2.3.4:5678").unwrap(), SocketAddr::from_str("6.6.6.6:53").unwrap()];
assert_eq!(
format!("{:?}", peers),
format!("{:?}", ser.decode("WsHI31HVpqxFNMNSPrvik22E WsHI34yOBcZIulKdtn2ik22E", None))
);
}
#[test]
fn decode_ttl() {
MockTimeSource::set_time(2000 * 3600);
let ser = BeaconSerializer::<MockTimeSource>::new(b"mysecretkey");
MockTimeSource::set_time(2000 * 3600);
assert_eq!(2, ser.decode("WsHI31EWDMBYxvITiILIrm2k9gEik22E", None).len());
MockTimeSource::set_time(2100 * 3600);
assert_eq!(2, ser.decode("WsHI31EWDMBYxvITiILIrm2k9gEik22E", None).len());
MockTimeSource::set_time(2005 * 3600);
assert_eq!(2, ser.decode("WsHI31EWDMBYxvITiILIrm2k9gEik22E", None).len());
MockTimeSource::set_time(1995 * 3600);
assert_eq!(2, ser.decode("WsHI31EWDMBYxvITiILIrm2k9gEik22E", None).len());
MockTimeSource::set_time(2000 * 3600);
assert_eq!(2, ser.decode("WsHI31EWDMBYxvITiILIrm2k9gEik22E", Some(24)).len());
MockTimeSource::set_time(1995 * 3600);
assert_eq!(2, ser.decode("WsHI31EWDMBYxvITiILIrm2k9gEik22E", Some(24)).len());
MockTimeSource::set_time(2005 * 3600);
assert_eq!(2, ser.decode("WsHI31EWDMBYxvITiILIrm2k9gEik22E", Some(24)).len());
MockTimeSource::set_time(2100 * 3600);
assert_eq!(0, ser.decode("WsHI31EWDMBYxvITiILIrm2k9gEik22E", Some(24)).len());
MockTimeSource::set_time(1900 * 3600);
assert_eq!(0, ser.decode("WsHI31EWDMBYxvITiILIrm2k9gEik22E", Some(24)).len());
}
#[test]
fn decode_invalid() {
MockTimeSource::set_time(2000 * 3600);
let ser = BeaconSerializer::<MockTimeSource>::new(b"mysecretkey");
assert_eq!(0, ser.decode("", None).len());
assert_eq!(0, ser.decode("WsHI3ik22E", None).len());
assert_eq!(0, ser.decode("WsHI3--", None).len());
assert_eq!(0, ser.decode("--ik22E", None).len());
assert_eq!(0, ser.decode("WsHI32EWDMBYxvITiILIrm2k9gEik22E", None).len());
assert_eq!(2, ser.decode("ik22EWsHI31EWDMBYxvITiILIrm2k9gEik22EWsHI3", None).len());
assert_eq!(2, ser.decode("WsHI3WsHI31EWDMBYxvITiILIrm2k9gEik22Eik22E", None).len());
}
#[test]
fn encode_decode() {
MockTimeSource::set_time(2000 * 3600);
let ser = BeaconSerializer::<MockTimeSource>::new(b"mysecretkey");
let peers = vec![SocketAddr::from_str("1.2.3.4:5678").unwrap(), SocketAddr::from_str("6.6.6.6:53").unwrap()];
let data = ser.encode(&peers);
let peers2 = ser.decode(&data, None);
assert_eq!(format!("{:?}", peers), format!("{:?}", peers2));
}
#[test]
fn encode_decode_file() {
MockTimeSource::set_time(2000 * 3600);
let ser = BeaconSerializer::<MockTimeSource>::new(b"mysecretkey");
let peers = vec![SocketAddr::from_str("1.2.3.4:5678").unwrap(), SocketAddr::from_str("6.6.6.6:53").unwrap()];
let file = tempfile::NamedTempFile::new().expect("Failed to create temp file");
assert!(ser.write_to_file(&peers, file.path()).is_ok());
let peers2 = ser.read_from_file(file.path(), None);
assert!(peers2.is_ok());
assert_eq!(format!("{:?}", peers), format!("{:?}", peers2.unwrap()));
}
#[test]
fn encode_decode_cmd() {
MockTimeSource::set_time(2000 * 3600);
let ser = BeaconSerializer::<MockTimeSource>::new(b"mysecretkey");
let peers = vec![SocketAddr::from_str("1.2.3.4:5678").unwrap(), SocketAddr::from_str("6.6.6.6:53").unwrap()];
let file = tempfile::NamedTempFile::new().expect("Failed to create temp file");
assert!(ser.write_to_cmd(&peers, &format!("echo $beacon > {}", file.path().display())).is_ok());
thread::sleep(Duration::from_millis(100));
let res = ser.read_from_cmd(&format!("cat {}", file.path().display()), None);
assert!(res.is_ok());
thread::sleep(Duration::from_millis(100));
let peers2 = ser.get_cmd_results();
assert!(peers2.is_some());
assert_eq!(format!("{:?}", peers), format!("{:?}", peers2.unwrap()));
}