diff options
| -rw-r--r-- | src/smtp_server.rs | 159 |
1 files changed, 158 insertions, 1 deletions
diff --git a/src/smtp_server.rs b/src/smtp_server.rs index 83a1093..bee00e9 100644 --- a/src/smtp_server.rs +++ b/src/smtp_server.rs @@ -1,4 +1,7 @@ -use std::net::{IpAddr, SocketAddr}; +use std::{ + fmt::Display, + net::{IpAddr, SocketAddr}, +}; use anyhow::Result; use tokio::{ @@ -44,6 +47,7 @@ impl SmtpServer { } }, }; + log::info!("Connected: {}", addr); let session = SessionHandler { addr, server_name: self.server_name.clone(), @@ -101,6 +105,9 @@ impl SessionHandler { if self.state == SessionState::AwaitingMailInput { if buffer.starts_with(".\r\n") { self.process_mail().await?; + writer + .write_all(Reply::Completed("Ok").to_string().as_bytes()) + .await?; continue; } @@ -117,13 +124,19 @@ impl SessionHandler { } Ok(v) => v, }; + log::debug!("COMMAND: {}", command); let res = self.apply(command).await?; + log::debug!("RESPONSE: {}", res); writer.write_all(res.to_string().as_bytes()).await?; if res == Reply::EndTransmission { break; } } + // Should wait for the client before closing but meh. Any transaction has already gone + // through anyway so... waiting for the client to close the connection as part of the + // protocol was a dumb choice, the client can't issue new commands anyway. + stream.shutdown().await?; Ok(()) } @@ -292,3 +305,147 @@ impl<'a> TryFrom<&'a str> for Command<'a> { Err(anyhow::format_err!("Invalid command")) } } + +impl Display for Command<'_> { + fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result { + match self { + Command::HELO(host) => write!(f, "HELO {}\r\n", host), + Command::MAIL(from) => write!(f, "MAIL FROM:<{}>\r\n", from), + Command::RCPT(to) => write!(f, "RCPT TO:<{}>\r\n", to), + Command::DATA => write!(f, "DATA\r\n"), + Command::QUIT => write!(f, "QUIT\r\n"), + } + } +} + +mod tests { + use std::net::SocketAddr; + + use tokio::{ + io::{AsyncBufReadExt, AsyncWriteExt, BufReader}, + net::TcpSocket, + spawn, + sync::mpsc::channel, + }; + + use crate::smtp_server::{Command, SmtpServer}; + + const DOMAIN: &str = "mail.example.local"; + const CLIENT_HOST: &str = "exploit"; + + #[tokio::test] + async fn receive_email() { + env_logger::init(); + let mut server = SmtpServer::new([127, 0, 0, 1], 9090, DOMAIN).await.unwrap(); + let (tx, mut rx) = channel(5); + let j = spawn(async move { + server.run(tx).await.unwrap(); + log::info!("IM DONE"); + }); + + let sock = TcpSocket::new_v4().unwrap(); + let mut s = sock + .connect(SocketAddr::new([127, 0, 0, 1].into(), 9090)) + .await + .unwrap(); + let (reader, mut writer) = s.split(); + let mut reader = BufReader::new(reader); + let mut buf = String::new(); + + assert!(reader.read_line(&mut buf).await.unwrap() > 0); + assert_eq!(buf.trim(), format!("220 {}", DOMAIN)); + + writer + .write_all(Command::HELO(CLIENT_HOST).to_string().as_bytes()) + .await + .unwrap(); + buf.clear(); + assert!(reader.read_line(&mut buf).await.unwrap() > 0); + assert_eq!(buf.trim(), format!("250 {}", DOMAIN)); + + writer + .write_all(Command::MAIL("mroik@poul.org").to_string().as_bytes()) + .await + .unwrap(); + buf.clear(); + assert!(reader.read_line(&mut buf).await.unwrap() > 0); + assert_eq!(buf.trim(), "250 Ok"); + + writer + .write_all(Command::RCPT("mroik@delayed.space").to_string().as_bytes()) + .await + .unwrap(); + buf.clear(); + assert!(reader.read_line(&mut buf).await.unwrap() > 0); + assert_eq!(buf.trim(), "250 Ok"); + + writer + .write_all(Command::DATA.to_string().as_bytes()) + .await + .unwrap(); + buf.clear(); + assert!(reader.read_line(&mut buf).await.unwrap() > 0); + assert_eq!(buf.trim(), "354 <CRLF>.<CRLF>"); + + writer.write_all(b"From: mroik@poul.org\r\n").await.unwrap(); + writer + .write_all(b"To: mroik@delayed.space\r\n") + .await + .unwrap(); + writer + .write_all(b"Date: Tue, 14 Apr 2026 23:00:00 +0200\r\n") + .await + .unwrap(); + writer + .write_all(b"Subject: This is a test\r\n") + .await + .unwrap(); + writer.write_all(b"\r\n").await.unwrap(); + writer + .write_all(b"Hey, this is a test. You can ignore this!\r\n") + .await + .unwrap(); + writer.write_all(b"\r\n").await.unwrap(); + writer.write_all(b"Mroik\r\n").await.unwrap(); + writer.write_all(b".\r\n").await.unwrap(); + buf.clear(); + assert!(reader.read_line(&mut buf).await.unwrap() > 0); + assert_eq!(buf.trim(), "250 Ok"); + + let lines = [ + "From: mroik@poul.org", + "To: mroik@delayed.space", + "Date: Tue, 14 Apr 2026 23:00:00 +0200", + "Subject: This is a test", + "", + "Hey, this is a test. You can ignore this!", + "", + "Mroik", + ]; + + let email = rx.recv().await.unwrap(); + assert_eq!(email.from, "mroik@poul.org"); + assert_eq!(email.recipient.len(), 1); + assert_eq!(email.recipient[0], "mroik@delayed.space"); + assert_eq!(email.data.trim(), lines.join("\r\n").trim()); + + // Close connection + writer + .write_all(Command::QUIT.to_string().as_bytes()) + .await + .unwrap(); + buf.clear(); + assert!(reader.read_line(&mut buf).await.unwrap() > 0); + assert_eq!(buf.trim(), "221 OK"); + + buf.clear(); + assert_eq!(reader.read_line(&mut buf).await.unwrap(), 0); + + s.shutdown().await.unwrap(); + // This is necessary because the server continues to run even after closing a connection as + // it continues to listen for new connections. + // + // In order to ensure that this doesn't affect other tests we have to abort it. + j.abort(); + } +} |