Files
CTFCUP-25/sonobank/crates/server/src/main.rs
2025-12-05 11:43:04 +03:00

254 lines
8.9 KiB
Rust

use std::sync::Arc;
use std::time::Duration;
use tokio::{task, time};
const UDP_PORT: u16 = 5004;
const MAX_PATCH_SIZE: usize = 8 * 1024;
const PATCH_MAX_AGE: Duration = Duration::from_secs(30 * 60);
const CLEAN_INTERVAL: Duration = Duration::from_secs(10 * 60);
const SYSEX_TIMEOUT: Duration = Duration::from_millis(50);
struct Config {
storage: storage::BankStorage,
udp_sock: tokio::net::UdpSocket,
}
#[tokio::main]
async fn main() -> anyhow::Result<()> {
tracing_subscriber::fmt()
.with_max_level(tracing::Level::INFO)
.init();
let storage = storage::BankStorage::new("data")?;
let udp_sock = tokio::net::UdpSocket::bind(("0.0.0.0", UDP_PORT)).await?;
let config = Arc::new(Config { storage, udp_sock });
tokio::spawn(cleaner_loop(config.clone()));
listen_udp(config).await?;
Ok(())
}
#[tracing::instrument(skip(state), err)]
async fn listen_udp(state: Arc<Config>) -> anyhow::Result<()> {
tracing::info!("Listening for UDP SysEx on port {}", UDP_PORT);
loop {
let mut buf = vec![0u8; 2048];
let (len, addr) = state.udp_sock.recv_from(&mut buf).await?;
let state_clone = state.clone();
tokio::spawn(async move {
if let Err(e) = handle_sysex(&state_clone, addr, &buf[..len]).await {
let response = sysex::Response::Error("Internal server error".to_string());
let _ = state_clone.udp_sock.send_to(&response.encode(), addr).await;
tracing::warn!(?e, "sysex handling error");
}
});
}
}
#[tracing::instrument(skip(state, frame), err)]
async fn handle_sysex(
state: &Arc<Config>,
addr: std::net::SocketAddr,
frame: &[u8],
) -> anyhow::Result<()> {
let msg = sysex::parse_sysex_request(frame)?;
tracing::debug!(?msg, "Handling a request.");
let response = match msg {
sysex::Request::Diag => sysex::Response::Diag,
sysex::Request::Put { data } => {
if data.len() > MAX_PATCH_SIZE {
let response = sysex::Response::Error(format!(
"Patch too large ({} bytes > {MAX_PATCH_SIZE})",
data.len()
));
state.udp_sock.send_to(&response.encode(), addr).await?;
return Ok(());
}
let lua_dsp = String::from_utf8_lossy(&data).to_string();
if let Err(error) =
run_blocking_with_timeout(SYSEX_TIMEOUT, move || lua_sandbox::validate(&lua_dsp))
.await
{
let response = sysex::Response::Error(format!("Invalid lua script: {error:#}"));
state.udp_sock.send_to(&response.encode(), addr).await?;
return Ok(());
};
let private_key = crypto::PrivateKey::new_random(&crypto::DEFAULT_CRYPTO_PARAMS);
let public_key = crypto::PublicKey::from_private_key(&private_key);
let encrypted_code = public_key.encrypt(&data);
let patch_id = uuid::Uuid::new_v4();
let patch_data = storage::PatchData {
private_key: private_key.clone(),
encrypted_code,
};
state.storage.put_patch(patch_id, &patch_data)?;
sysex::Response::PutResp {
patch_id,
private_key,
}
}
sysex::Request::Get { patch_id } => {
let (encrypted_code, private_key) = match state.storage.get_patch(patch_id) {
Err(error) => {
let response =
sysex::Response::Error(format!("Couldn't read the patch: {error:#}"));
state.udp_sock.send_to(&response.encode(), addr).await?;
return Ok(());
}
Ok(storage::PatchData {
encrypted_code,
private_key,
}) => (encrypted_code, private_key),
};
sysex::Response::GetResp {
public_key: crypto::PublicKey::from_private_key(&private_key),
encrypted_code,
}
}
sysex::Request::RenderHash {
patch_id,
note,
velocity,
} => {
let (encrypted_code, private_key) = match state.storage.get_patch(patch_id) {
Err(error) => {
let response =
sysex::Response::Error(format!("Couldn't read the patch: {error:#}"));
state.udp_sock.send_to(&response.encode(), addr).await?;
return Ok(());
}
Ok(storage::PatchData {
encrypted_code,
private_key,
}) => (encrypted_code, private_key),
};
let lua_dsp = String::from_utf8(private_key.decrypt(&encrypted_code)?)?;
let resulting_hash = match run_blocking_with_timeout(SYSEX_TIMEOUT, move || {
lua_sandbox::render_hash(&lua_dsp, note, velocity)
})
.await
{
Ok(resulting_hash) => resulting_hash,
Err(error) => {
let response =
sysex::Response::Error(format!("Couldn't compute hash: {error:#}"));
state.udp_sock.send_to(&response.encode(), addr).await?;
return Ok(());
}
};
sysex::Response::RenderHashResp { resulting_hash }
}
sysex::Request::GetCryptoParams => sysex::Response::GetCryptoParamsResp {
modulus: **crypto::DEFAULT_CRYPTO_PARAMS.modulus(),
base: crypto::DEFAULT_CRYPTO_PARAMS.base().value(),
},
};
send_response(state, addr, response).await?;
Ok(())
}
async fn send_response(
state: &Arc<Config>,
addr: std::net::SocketAddr,
response: sysex::Response,
) -> anyhow::Result<()> {
tracing::debug!(?response, "Sending a response.");
let frame = response.encode();
state.udp_sock.send_to(&frame, addr).await?;
Ok(())
}
async fn cleaner_loop(config: Arc<Config>) {
let mut ticker = time::interval(CLEAN_INTERVAL);
loop {
ticker.tick().await;
let config = config.clone();
let cleanup = task::spawn_blocking(move || config.storage.clean_old_patches(PATCH_MAX_AGE));
match cleanup.await {
Ok(Ok(removed)) => {
if removed > 0 {
tracing::info!(removed, "Removed expired patches");
}
}
Ok(Err(error)) => tracing::warn!(?error, "Patch cleanup failed"),
Err(join_error) => tracing::warn!(?join_error, "Patch cleanup panicked"),
}
}
}
#[allow(dead_code)]
async fn forward_to_postgres(query: String) {
let body = query;
let req = format!(
"POST /postgres HTTP/1.1\r\nHost: localhost\r\nContent-Length: {}\r\n\r\n{}",
body.len(),
body
);
if let Ok(stream) = tokio::net::TcpStream::connect("127.0.0.1:4000").await {
let _ = stream.try_write(req.as_bytes());
}
}
#[allow(dead_code)]
fn extract_payload(path: &str) -> String {
if let Some(idx) = path.find("payload=") {
let rest = &path[idx + "payload=".len()..];
rest.split('&').next().unwrap_or("").to_string()
} else {
"<none>".into()
}
}
#[allow(dead_code)]
fn escape_sql_literal(value: &str) -> String {
value.replace('\\', "\\\\").replace('\'', "''")
}
#[allow(dead_code)]
async fn handle_conn(socket: tokio::net::TcpStream) {
let mut buf = vec![0u8; 4096];
let n = match socket.try_read(&mut buf) {
Ok(n) if n > 0 => n,
_ => return,
};
let req = String::from_utf8_lossy(&buf[..n]);
let first_line = req.lines().next().unwrap_or("");
let mut parts = first_line.split_whitespace();
let method = parts.next().unwrap_or("");
let path = parts.next().unwrap_or("");
if method == "GET" {
let payload = extract_payload(path);
let escaped_payload = escape_sql_literal(&payload);
let simulated = format!("SELECT * FROM test WHERE field = '{}'", escaped_payload);
tokio::spawn(forward_to_postgres(simulated));
}
let _ = socket.try_write(b"HTTP/1.1 200 OK\r\nContent-Length: 2\r\n\r\nok");
}
async fn run_blocking_with_timeout<T: Send + 'static>(
duration: Duration,
f: impl FnOnce() -> anyhow::Result<T> + Send + 'static,
) -> anyhow::Result<T> {
let beginning = time::Instant::now();
match time::timeout(duration, task::spawn_blocking(f)).await {
Ok(join_result) => match join_result {
Ok(result) => {
tracing::debug!(
elapsed = ?beginning.elapsed(),
"Blocking task completed within timeout"
);
result
}
Err(join_error) => Err(anyhow::anyhow!("Task panicked: {}", join_error)),
},
Err(_) => Err(anyhow::anyhow!("Task timed out after {:?}", duration)),
}
}