From 7ba68cedbd912713c5ee1c6add99fd432bd494c8 Mon Sep 17 00:00:00 2001
From: soruh <mail@soruh.de>
Date: Sun, 9 Jul 2023 00:43:52 +0200
Subject: [PATCH] only allow clients that are already registered

---
 src/client.rs  | 51 ++++++++++++++++++++++++++++++++------------------
 src/packets.rs |  1 +
 2 files changed, 34 insertions(+), 18 deletions(-)

diff --git a/src/client.rs b/src/client.rs
index b518d80..573f7b4 100644
--- a/src/client.rs
+++ b/src/client.rs
@@ -16,11 +16,19 @@ use crate::{
     auth::dyn_ip_update,
     constants::{AUTH_TIMEOUT, CALL_ACK_TIMEOUT, CALL_TIMEOUT, PING_TIMEOUT, SEND_PING_INTERVAL},
     http::peer_query,
-    packets::{Header, Packet, PacketKind, RemConnect, REJECT_OOP, REJECT_TIMEOUT},
+    packets::{
+        Header, Packet, PacketKind, RemConnect, REJECT_OOP, REJECT_TIMEOUT, REJECT_UNKNOWN_CLIENT,
+    },
     ports::{PortHandler, PortStatus},
     Config, HandlerMetadata,
 };
 
+pub enum AuthResult {
+    OutOfPorts,
+    UnknownClient,
+    Success { port: u16 },
+}
+
 /// # Errors
 /// - the client authentication fails
 #[instrument(skip(config, port_handler, handler_metadata))]
@@ -30,7 +38,16 @@ async fn authenticate(
     handler_metadata: &mut HandlerMetadata,
     number: u32,
     pin: u16,
-) -> eyre::Result<Option<u16>> {
+) -> eyre::Result<AuthResult> {
+    // TODO: do we want to cache this? If so, for how long?
+    let name = peer_query(&config.dyn_ip_server, number).await?;
+
+    let Some(name) = name else {
+        return Ok(AuthResult::UnknownClient);
+    };
+
+    info!(%name, "found client");
+
     let mut authenticated = false;
     loop {
         let mut updated_server = false;
@@ -41,7 +58,7 @@ async fn authenticate(
             .allocate_port_for_number(config, number);
 
         let Some(port) = port else {
-            return Ok(None);
+            return Ok(AuthResult::OutOfPorts);
         };
 
         // make sure the client is authenticated before opening any ports
@@ -71,19 +88,10 @@ async fn authenticate(
                 let _ip = dyn_ip_update(&config.dyn_ip_server, number, pin, port).await?;
             }
 
-            // TODO: do we want to cache this? If so, for how long?
-            #[cfg(feature = "debug_server")]
-            let name = peer_query(&config.dyn_ip_server, number).await?;
-
             let mut port_handler = port_handler.lock().await;
-
-            #[cfg(feature = "debug_server")]
-            if let Some(name) = name {
-                info!(%name, "found client name");
-                port_handler.names.insert(number, name);
-            }
-
             port_handler.register_update();
+
+            port_handler.names.insert(number, name);
             port_handler
                 .port_state
                 .entry(port)
@@ -92,7 +100,7 @@ async fn authenticate(
 
             handler_metadata.port = Some(port);
 
-            break Ok(Some(port));
+            break Ok(AuthResult::Success { port });
         }
 
         port_handler.lock().await.mark_port_error(number, port);
@@ -340,9 +348,16 @@ pub async fn handler(
 
     handler_metadata.number = Some(number);
 
-    let Some(port) = authenticate(config, port_handler, handler_metadata, number, pin).await? else {
-        writer.write_all(REJECT_OOP).await?;
-        return Ok(());
+    let port = match authenticate(config, port_handler, handler_metadata, number, pin).await? {
+        AuthResult::OutOfPorts => {
+            writer.write_all(REJECT_OOP).await?;
+            return Ok(());
+        }
+        AuthResult::UnknownClient => {
+            writer.write_all(REJECT_UNKNOWN_CLIENT).await?;
+            return Ok(());
+        }
+        AuthResult::Success { port } => port,
     };
 
     info!(%addr, number, port, "authenticated");
diff --git a/src/packets.rs b/src/packets.rs
index 3ae3d30..310ff74 100644
--- a/src/packets.rs
+++ b/src/packets.rs
@@ -10,6 +10,7 @@ use tokio::{
 
 pub const REJECT_OOP: &[u8; 6] = b"\x04\x04oop\x00";
 pub const REJECT_TIMEOUT: &[u8; 10] = b"\x04\x08timeout\x00";
+pub const REJECT_UNKNOWN_CLIENT: &[u8; 17] = b"\x04\x0funknown client\x00";
 
 #[derive(Debug)]
 pub enum Error {