From 00db8c6359f950087827b6e7390c1a973b718f98 Mon Sep 17 00:00:00 2001
From: yyforyongyu <yong2452@gmail.com>
Date: Sat, 31 May 2025 04:56:54 +0800
Subject: [PATCH] lnd: move peer perms assignment into `peerConnected`

When the callback is called in `scheduledPeerConnection`, it is
referencing the old `access` variable which was created when the peer
was first connected. However, if this peer opens a channel with us and
goes offline, or another inbound connection is made from this peer, we
may still use the old `access` value. To fix it, we need to make sure we
always get the fresh perm by calling `assignPeerPerms` inside
`peerConnected`.
---
 server.go | 68 ++++++++++++++++++++++---------------------------------
 1 file changed, 27 insertions(+), 41 deletions(-)

diff --git a/server.go b/server.go
index 5d12e3e2d..0aec863ee 100644
--- a/server.go
+++ b/server.go
@@ -4002,22 +4002,6 @@ func (s *server) InboundPeerConnected(conn net.Conn) {
 	s.mu.Lock()
 	defer s.mu.Unlock()
 
-	// If the remote node's public key is banned, drop the connection.
-	access, err := s.peerAccessMan.assignPeerPerms(nodePub)
-	if err != nil {
-		// Clean up the persistent peer maps if we're dropping this
-		// connection.
-		s.bannedPersistentPeerConnection(pubStr)
-
-		srvrLog.Debugf("Dropping connection for %x since we are out "+
-			"of restricted-access connection slots: %v.", pubSer,
-			err)
-
-		conn.Close()
-
-		return
-	}
-
 	// If we already have an outbound connection to this peer, then ignore
 	// this new connection.
 	if p, ok := s.outboundPeers[pubStr]; ok {
@@ -4052,7 +4036,7 @@ func (s *server) InboundPeerConnected(conn net.Conn) {
 		// We were unable to locate an existing connection with the
 		// target peer, proceed to connect.
 		s.cancelConnReqs(pubStr, nil)
-		s.peerConnected(conn, nil, true, access)
+		s.peerConnected(conn, nil, true)
 
 	case nil:
 		// We already have a connection with the incoming peer. If the
@@ -4084,7 +4068,7 @@ func (s *server) InboundPeerConnected(conn net.Conn) {
 		s.removePeer(connectedPeer)
 		s.ignorePeerTermination[connectedPeer] = struct{}{}
 		s.scheduledPeerConnection[pubStr] = func() {
-			s.peerConnected(conn, nil, true, access)
+			s.peerConnected(conn, nil, true)
 		}
 	}
 }
@@ -4109,25 +4093,6 @@ func (s *server) OutboundPeerConnected(connReq *connmgr.ConnReq, conn net.Conn)
 	s.mu.Lock()
 	defer s.mu.Unlock()
 
-	access, err := s.peerAccessMan.assignPeerPerms(nodePub)
-	if err != nil {
-		// Clean up the persistent peer maps if we're dropping this
-		// connection.
-		s.bannedPersistentPeerConnection(pubStr)
-
-		srvrLog.Debugf("Dropping connection for %x since we are out "+
-			"of restricted-access connection slots: %v.", pubSer,
-			err)
-
-		if connReq != nil {
-			s.connMgr.Remove(connReq.ID())
-		}
-
-		conn.Close()
-
-		return
-	}
-
 	// If we already have an inbound connection to this peer, then ignore
 	// this new connection.
 	if p, ok := s.inboundPeers[pubStr]; ok {
@@ -4162,7 +4127,7 @@ func (s *server) OutboundPeerConnected(connReq *connmgr.ConnReq, conn net.Conn)
 		return
 	}
 
-	srvrLog.Infof("Established connection to: %x@%v", pubStr,
+	srvrLog.Infof("Established outbound connection to: %x@%v", pubStr,
 		conn.RemoteAddr())
 
 	if connReq != nil {
@@ -4186,7 +4151,7 @@ func (s *server) OutboundPeerConnected(connReq *connmgr.ConnReq, conn net.Conn)
 	case ErrPeerNotConnected:
 		// We were unable to locate an existing connection with the
 		// target peer, proceed to connect.
-		s.peerConnected(conn, connReq, false, access)
+		s.peerConnected(conn, connReq, false)
 
 	case nil:
 		// We already have a connection with the incoming peer. If the
@@ -4220,7 +4185,7 @@ func (s *server) OutboundPeerConnected(connReq *connmgr.ConnReq, conn net.Conn)
 		s.removePeer(connectedPeer)
 		s.ignorePeerTermination[connectedPeer] = struct{}{}
 		s.scheduledPeerConnection[pubStr] = func() {
-			s.peerConnected(conn, connReq, false, access)
+			s.peerConnected(conn, connReq, false)
 		}
 	}
 }
@@ -4353,12 +4318,33 @@ func (s *server) notifyFundingTimeoutPeerEvent(op wire.OutPoint,
 // starting all the goroutines the peer needs to function properly. The inbound
 // boolean should be true if the peer initiated the connection to us.
 func (s *server) peerConnected(conn net.Conn, connReq *connmgr.ConnReq,
-	inbound bool, access peerAccessStatus) {
+	inbound bool) {
 
 	brontideConn := conn.(*brontide.Conn)
 	addr := conn.RemoteAddr()
 	pubKey := brontideConn.RemotePub()
 
+	// If the remote node's public key is banned, drop the connection.
+	//
+	// TODO(yy): Consider perform this check in
+	// `peerAccessMan.addPeerAccess`.
+	access, err := s.peerAccessMan.assignPeerPerms(pubKey)
+	if err != nil {
+		pubSer := pubKey.SerializeCompressed()
+
+		// Clean up the persistent peer maps if we're dropping this
+		// connection.
+		s.bannedPersistentPeerConnection(string(pubSer))
+
+		srvrLog.Debugf("Dropping connection for %x since we are out "+
+			"of restricted-access connection slots: %v.", pubSer,
+			err)
+
+		conn.Close()
+
+		return
+	}
+
 	srvrLog.Infof("Finalizing connection to %x@%s, inbound=%v",
 		pubKey.SerializeCompressed(), addr, inbound)