From 639feabb166e75b2d666fbd9f879eaef0a274460 Mon Sep 17 00:00:00 2001
From: Neeraj Sathish Kumar <neerajcodz@gmail.com>
Date: Tue, 30 Jun 2026 14:51:25 +0530
Subject: [PATCH] fix: enforce link relay input permissions

---
 apis/link/src/relay.ts             | 37 +++++++++++++++++++++++++++---
 crates/orphix-core/src/link/mod.rs | 20 +++++++++++++++-
 2 files changed, 53 insertions(+), 4 deletions(-)

diff --git a/apis/link/src/relay.ts b/apis/link/src/relay.ts
index fb0a031..093f010 100644
--- a/apis/link/src/relay.ts
+++ b/apis/link/src/relay.ts
@@ -37,6 +37,7 @@ interface Client {
   deviceId: string;
   role: "desktop" | "mobile";
   sessionId: string;
+  mode: string;
 }
 
 const sessions = new Map<string, { desktop: Client | null; mobile: Client | null }>();
@@ -86,6 +87,12 @@ export function handleRelaySocket(socket: WebSocket, app: FastifyInstance) {
         return;
       }
 
+      if (session.status !== "approved") {
+        sendJson(socket, { type: "relay.reject", reason: "Session not approved" });
+        socket.close();
+        return;
+      }
+
       // Verify deviceId matches session participants
       if (role === "desktop" && session.desktopDeviceId !== deviceId) {
         sendJson(socket, { type: "relay.reject", reason: "deviceId mismatch" });
@@ -100,7 +107,14 @@ export function handleRelaySocket(socket: WebSocket, app: FastifyInstance) {
 
       console.log(`[relay] ${role} authenticated for session ${sessionId}, device ${deviceId}`);
 
-      client = { socket, userId: payload.sub, deviceId, role, sessionId };
+      client = {
+        socket,
+        userId: payload.sub,
+        deviceId,
+        role,
+        sessionId,
+        mode: String(session.mode || ""),
+      };
       authenticated = true;
 
       // Register in session
@@ -114,7 +128,8 @@ export function handleRelaySocket(socket: WebSocket, app: FastifyInstance) {
 
       // Set presence
       const redis = getRedis();
-      const presenceKey = role === "desktop" ? `presence:desktop:${deviceId}` : `presence:mobile:${deviceId}`;
+      const presenceKey =
+        role === "desktop" ? `presence:desktop:${deviceId}` : `presence:mobile:${deviceId}`;
       await redis.setex(presenceKey, 60, "online");
 
       sendJson(socket, { type: "relay.ready", sessionId, role });
@@ -124,6 +139,19 @@ export function handleRelaySocket(socket: WebSocket, app: FastifyInstance) {
 
     // Forward messages to the other peer
     if (client) {
+      if (
+        client.role === "mobile" &&
+        msg.type === "relay.message" &&
+        msg.direction === "input" &&
+        client.mode !== "full_control"
+      ) {
+        sendJson(socket, {
+          type: "relay.reject",
+          reason: "Terminal input requires full_control mode",
+        });
+        return;
+      }
+
       const sess = sessions.get(client.sessionId);
       if (!sess) return;
 
@@ -156,7 +184,10 @@ export function handleRelaySocket(socket: WebSocket, app: FastifyInstance) {
 
     // Clear presence
     const redis = getRedis();
-    const presenceKey = client.role === "desktop" ? `presence:desktop:${client.deviceId}` : `presence:mobile:${client.deviceId}`;
+    const presenceKey =
+      client.role === "desktop"
+        ? `presence:desktop:${client.deviceId}`
+        : `presence:mobile:${client.deviceId}`;
     await redis.del(presenceKey);
 
     console.log(`[relay] ${client.role} disconnected from session ${client.sessionId}`);
diff --git a/crates/orphix-core/src/link/mod.rs b/crates/orphix-core/src/link/mod.rs
index 9c050e6..a3a34f5 100644
--- a/crates/orphix-core/src/link/mod.rs
+++ b/crates/orphix-core/src/link/mod.rs
@@ -135,6 +135,16 @@ impl LinkManager {
         self.relay_output_tx.clone()
     }
 
+    fn session_allows_terminal_input(&self, session_id: &str, terminal_id: &str) -> bool {
+        if self.session.session_id.as_deref() != Some(session_id) {
+            return false;
+        }
+        if self.session.mode.as_deref() != Some("full_control") {
+            return false;
+        }
+        self.relay.get_terminal_for_session(session_id).as_deref() == Some(terminal_id)
+    }
+
     /// Phase 1 (sync): Validate params and create device identity. No network I/O.
     /// Must be called with the parking_lot lock held.
     pub fn prepare_enable(&mut self, params: &EnableParams) -> Result<PreparedEnable, String> {
@@ -495,8 +505,16 @@ impl LinkManager {
                 self.send_workspace_snapshot();
             }
 
-            LinkMessage::RelayMessage { terminal_id, data, direction, .. } => {
+            LinkMessage::RelayMessage { session_id, terminal_id, data, direction } => {
                 if direction == "input" {
+                    if !self.session_allows_terminal_input(&session_id, &terminal_id) {
+                        eprintln!(
+                            "[link] Denied relay input: session={}, terminal={}, mode={:?}",
+                            session_id, terminal_id, self.session.mode
+                        );
+                        return;
+                    }
+
                     // Check if this is an RPC call (JSON with type field)
                     if data.starts_with('{') {
                         if let Ok(msg) = serde_json::from_str::<serde_json::Value>(&data) {