feat: added connection and authentication

client can now generate a server binary, and try to connect to it and
get capabilities

sparse-05/sparse-05-client/src/commands/connect/mod.rs

@@ -1,17 +1,51 @@
 use std::{net::SocketAddr, path::PathBuf, sync::Arc};
 
-use ed25519_dalek::{Keypair, Signer};
-use sparse_05_common::messages::CONNECT_MESSAGE;
+use anyhow::{bail, Context};
+use ed25519_dalek::{Keypair, Signature, Signer, Verifier};
+use rmp_serde::decode::ReadSlice;
+use sparse_05_common::messages::{Capabilities, Response, CONNECTED_MESSAGE, CONNECT_MESSAGE};
 use tokio::{fs, net::UdpSocket};
 
 use crate::configs::ClientConfig;
 
 enum State {
+    Authenticating,
     Ready,
     UploadingFile,
     DownloadingFile,
 }
 
+struct Connection {
+    config: ClientConfig,
+    foreign_sign_pubkey: ed25519_dalek::PublicKey,
+    foreign_enc_pubkey: ecies_ed25519::PublicKey,
+}
+
+impl Connection {
+    fn decrypt_and_verify(&self, data: &[u8]) -> anyhow::Result<Response> {
+        if data.len() < 65 {
+            bail!("unable to parse out signature from message");
+        }
+
+        let signature: [u8; 64] = data[..64].try_into().unwrap();
+        self.foreign_sign_pubkey
+            .verify(data, &Signature::from(signature))?;
+
+        let data = ecies_ed25519::decrypt(&self.config.enc_privkey, &data[64..])?;
+
+        Ok(rmp_serde::from_slice(&data)?)
+    }
+
+    fn encrypt_and_sign(&self, data: &[u8]) -> anyhow::Result<Vec<u8>> {
+        let mut rng = rand::thread_rng();
+        let data = ecies_ed25519::encrypt(&self.foreign_enc_pubkey, data, &mut rng)?;
+
+        let signature = self.config.keypair.sign(&data);
+
+        Ok([&signature.to_bytes(), &*data].concat())
+    }
+}
+
 pub async fn connect(config: PathBuf, ip: SocketAddr) -> anyhow::Result<()> {
     let config = fs::read(&config).await?;
     let config: ClientConfig = rmp_serde::from_slice(&config)?;
@@ -21,7 +55,84 @@ pub async fn connect(config: PathBuf, ip: SocketAddr) -> anyhow::Result<()> {
     let connect_signature = config.keypair.sign(CONNECT_MESSAGE).to_bytes();
     let connect_msg = &[&connect_signature, CONNECT_MESSAGE].concat();
 
-    remote.send_to(connect_msg, ip).await?;
+    let mut counter = 0;
+
+    let (foreign_sign_pubkey, foreign_enc_pubkey, capabilities) = loop {
+        if counter > 5 {
+            bail!("could not connect to server");
+        }
+
+        remote.send_to(connect_msg, ip).await?;
+
+        let mut buf = [0u8; 2000];
+
+        match tokio::time::timeout(
+            std::time::Duration::from_millis(250),
+            remote.recv_from(&mut buf),
+        )
+        .await
+        {
+            Ok(packet) => {
+                let (count, addr) = packet?;
+
+                if addr != ip {
+                    bail!("received response from wrong source");
+                }
+
+                let data = &buf[..count];
+
+                if data.len() < 65 {
+                    bail!("could not get signature from server");
+                }
+
+                let signature: [u8; 64] = data[..64].try_into().unwrap();
+                let data = &data[64..];
+
+                let Ok(foreign_keys) = ecies_ed25519::decrypt(&config.enc_privkey, data) else {
+                    counter += 1;
+                    continue;
+                };
+
+                if foreign_keys.len()
+                    < ed25519_dalek::PUBLIC_KEY_LENGTH + ecies_ed25519::PUBLIC_KEY_LENGTH
+                {
+                    bail!("could not get public keys from the server");
+                }
+
+                let foreign_sign_pubkey = ed25519_dalek::PublicKey::from_bytes(
+                    &foreign_keys[..ed25519_dalek::PUBLIC_KEY_LENGTH],
+                )?;
+                let foreign_enc_pubkey = ecies_ed25519::PublicKey::from_bytes(
+                    &foreign_keys[ed25519_dalek::PUBLIC_KEY_LENGTH
+                        ..(ed25519_dalek::PUBLIC_KEY_LENGTH + ecies_ed25519::PUBLIC_KEY_LENGTH)],
+                )?;
+
+                let capabilities: Capabilities = rmp_serde::from_slice(
+                    &foreign_keys
+                        [(ed25519_dalek::PUBLIC_KEY_LENGTH + ecies_ed25519::PUBLIC_KEY_LENGTH)..],
+                )?;
+
+                foreign_sign_pubkey.verify(data, &Signature::from(signature))?;
+
+                break (foreign_sign_pubkey, foreign_enc_pubkey, capabilities);
+            }
+            Err(_) => {
+                counter += 1;
+            }
+        }
+    };
+
+    let connection = Connection {
+        config,
+        foreign_enc_pubkey,
+        foreign_sign_pubkey,
+    };
+
+    remote
+        .send_to(&connection.encrypt_and_sign(CONNECTED_MESSAGE)?, ip)
+        .await?;
+
+    println!("connected! {:?}", capabilities);
 
     Ok(())
 }

sparse-05/sparse-05-client/src/commands/generate.rs

@@ -16,6 +16,7 @@ pub const SPARSE_SERVER_BINARY: &'static [u8] =
 pub async fn generate(mut name: PathBuf, port: u16) -> anyhow::Result<()> {
     let mut csprng = rand::thread_rng();
     let keypair = Keypair::generate(&mut csprng);
+    let (enc_privkey, enc_pubkey) = ecies_ed25519::generate_keypair(&mut csprng);
 
     let mut file = fs::OpenOptions::new()
         .write(true)
@@ -28,11 +29,17 @@ pub async fn generate(mut name: PathBuf, port: u16) -> anyhow::Result<()> {
     file.write_all(CONFIG_SEPARATOR).await?;
     file.write_all(&port.to_be_bytes()[..]).await?;
     file.write_all(keypair.public.as_bytes()).await?;
+    file.write_all(enc_pubkey.as_bytes()).await?;
 
-    let config = ClientConfig { keypair, port };
+    let config = ClientConfig {
+        keypair,
+        enc_privkey,
+        enc_pubkey,
+        port,
+    };
 
     let mut file_part = name.file_name().unwrap().to_owned();
-    file_part.push(OsString::from(".conf"));
+    file_part.push(OsString::from(".scon"));
     name.pop();
     name.push(file_part);
     let mut file = fs::OpenOptions::new()

sparse-05/sparse-05-client/src/configs.rs

@@ -4,5 +4,7 @@ use serde::{Deserialize, Serialize};
 #[derive(Serialize, Deserialize)]
 pub struct ClientConfig {
     pub keypair: Keypair,
+    pub enc_pubkey: ecies_ed25519::PublicKey,
+    pub enc_privkey: ecies_ed25519::SecretKey,
     pub port: u16,
 }