From 8fccbe69b93b9703156e4c8a2c282e62ca533f7e Mon Sep 17 00:00:00 2001
From: jack <jackjackbits@users.noreply.github.com>
Date: Tue, 22 Jul 2025 11:06:57 +0200
Subject: [PATCH] Fix session destruction race condition causing handshake
 delays

Root cause: When receiving a handshake initiation (32 bytes) from a peer
with whom we already had an established session, the code would destroy
the existing session to "help" the other side. This created a cascade:
- Peer A completes handshake with Peer B
- Peer A sends message, realizes no session, initiates handshake
- Peer B destroys its working session to "help"
- Peer B now has no session, initiates handshake
- Both peers keep destroying each other's sessions

Fix:
- Never destroy an established session when receiving new handshake attempts
- Add early check in handshake initiation to skip if session exists
- Clear handshake rate limit timers when session already established

This eliminates the delays and repeated handshakes seen in the logs.
---
 bitchat/Noise/NoiseSession.swift            | 15 ++++-----------
 bitchat/Services/BluetoothMeshService.swift |  8 ++++++++
 2 files changed, 12 insertions(+), 11 deletions(-)

diff --git a/bitchat/Noise/NoiseSession.swift b/bitchat/Noise/NoiseSession.swift
index da873cb9..2f8b2eb7 100644
--- a/bitchat/Noise/NoiseSession.swift
+++ b/bitchat/Noise/NoiseSession.swift
@@ -319,18 +319,11 @@ class NoiseSessionManager {
             var existingSession: NoiseSession? = nil
             
             if let existing = sessions[peerID] {
-                // If we have an established session, we might need to help the other side complete theirs
+                // If we have an established session, reject new handshake attempts
                 if existing.isEstablished() {
-                    // If this is a handshake initiation (32 bytes), the other side doesn't have a session
-                    // We should complete the handshake to help them establish their session
-                    if message.count == 32 {
-                        // Remove existing session and create new one
-                        sessions.removeValue(forKey: peerID)
-                        shouldCreateNew = true
-                    } else {
-                        // For other handshake messages, ignore if already established
-                        throw NoiseSessionError.alreadyEstablished
-                    }
+                    // Don't destroy our working session just because the other side is confused
+                    // They should detect the established session through successful message exchange
+                    throw NoiseSessionError.alreadyEstablished
                 } else {
                     // If we're in the middle of a handshake and receive a new initiation,
                     // reset and start fresh (the other side may have restarted)
diff --git a/bitchat/Services/BluetoothMeshService.swift b/bitchat/Services/BluetoothMeshService.swift
index 29a9f0a5..56b4d641 100644
--- a/bitchat/Services/BluetoothMeshService.swift
+++ b/bitchat/Services/BluetoothMeshService.swift
@@ -3368,6 +3368,14 @@ extension BluetoothMeshService: CBPeripheralManagerDelegate {
         
         SecurityLogger.log("Initiating Noise handshake with \(peerID)", category: SecurityLogger.noise, level: .info)
         
+        // Check if we already have an established session
+        if noiseService.hasEstablishedSession(with: peerID) {
+            SecurityLogger.log("Already have established session with \(peerID)", category: SecurityLogger.noise, level: .debug)
+            // Clear any lingering handshake attempt time
+            handshakeAttemptTimes.removeValue(forKey: peerID)
+            return
+        }
+        
         // Check if we've recently tried to handshake with this peer
         if let lastAttempt = handshakeAttemptTimes[peerID],
            Date().timeIntervalSince(lastAttempt) < handshakeTimeout {