From b3425ba1a3b834ccd6e6d909cc8b1d78d6f02cae Mon Sep 17 00:00:00 2001
From: Simon Ser <contact@emersion.fr>
Date: Mon, 21 Mar 2022 15:02:54 +0100
Subject: [PATCH] downstream: process BOUNCER BIND in downstreamConn.welcome

This allows clients to send BOUNCER BIND before SASL auth, or to
use BOUNCER BIND with PASS.
---
 downstream.go | 61 ++++++++++++++++++++++++++-------------------------
 1 file changed, 31 insertions(+), 30 deletions(-)

diff --git a/downstream.go b/downstream.go
index 991fadc..b26141c 100644
--- a/downstream.go
+++ b/downstream.go
@@ -289,7 +289,10 @@ type downstreamSASL struct {
 type downstreamRegistration struct {
 	nick     string
 	username string
-	password string
+	password string // from PASS
+
+	networkName string
+	networkID   int64
 }
 
 type downstreamConn struct {
@@ -301,7 +304,6 @@ type downstreamConn struct {
 	user            *user
 	nick            string
 	nickCM          string
-	networkName     string
 	clientName      string
 	realname        string
 	hostname        string
@@ -776,21 +778,7 @@ func (dc *downstreamConn) handleMessageUnregistered(ctx context.Context, msg *ir
 				return err
 			}
 
-			var match *network
-			for _, net := range dc.user.networks {
-				if net.ID == id {
-					match = net
-					break
-				}
-			}
-			if match == nil {
-				return ircError{&irc.Message{
-					Command: "FAIL",
-					Params:  []string{"BOUNCER", "INVALID_NETID", idStr, "Unknown network ID"},
-				}}
-			}
-
-			dc.networkName = match.GetName()
+			dc.registration.networkID = id
 		}
 	default:
 		dc.logger.Printf("unhandled message: %v", msg)
@@ -1243,7 +1231,7 @@ func (dc *downstreamConn) authenticate(ctx context.Context, username, password s
 		return fmt.Errorf("user not active")
 	}
 	dc.clientName = clientName
-	dc.networkName = networkName
+	dc.registration.networkName = networkName
 	return nil
 }
 
@@ -1295,9 +1283,10 @@ func (dc *downstreamConn) register(ctx context.Context) error {
 			Params:  []string{dc.nick, "Client name mismatch in usernames"},
 		}}
 	}
-	if dc.networkName == "" {
-		dc.networkName = fallbackNetworkName
-	} else if fallbackNetworkName != "" && dc.networkName != fallbackNetworkName {
+
+	if dc.registration.networkName == "" {
+		dc.registration.networkName = fallbackNetworkName
+	} else if fallbackNetworkName != "" && dc.registration.networkName != fallbackNetworkName {
 		return ircError{&irc.Message{
 			Command: irc.ERR_ERRONEUSNICKNAME,
 			Params:  []string{dc.nick, "Network name mismatch in usernames"},
@@ -1305,31 +1294,41 @@ func (dc *downstreamConn) register(ctx context.Context) error {
 	}
 
 	dc.registered = true
-	dc.registration = nil
 	dc.logger.Printf("registration complete for user %q", dc.user.Username)
 	return nil
 }
 
 func (dc *downstreamConn) loadNetwork(ctx context.Context) error {
-	if dc.networkName == "*" {
+	if id := dc.registration.networkID; id != 0 {
+		network := dc.user.getNetworkByID(id)
+		if network == nil {
+			return ircError{&irc.Message{
+				Command: "FAIL",
+				Params:  []string{"BOUNCER", "INVALID_NETID", fmt.Sprintf("%v", id), "Unknown network ID"},
+			}}
+		}
+		dc.network = network
+		return nil
+	}
+
+	if dc.registration.networkName == "*" {
 		if !dc.srv.Config().MultiUpstream {
 			return ircError{&irc.Message{
 				Command: irc.ERR_PASSWDMISMATCH,
 				Params:  []string{dc.nick, fmt.Sprintf("Multi-upstream mode is disabled on this server")},
 			}}
 		}
-		dc.networkName = ""
 		dc.isMultiUpstream = true
 		return nil
 	}
 
-	if dc.networkName == "" {
+	if dc.registration.networkName == "" {
 		return nil
 	}
 
-	network := dc.user.getNetwork(dc.networkName)
+	network := dc.user.getNetwork(dc.registration.networkName)
 	if network == nil {
-		addr := dc.networkName
+		addr := dc.registration.networkName
 		if !strings.ContainsRune(addr, ':') {
 			addr = addr + ":6697"
 		}
@@ -1339,7 +1338,7 @@ func (dc *downstreamConn) loadNetwork(ctx context.Context) error {
 			dc.logger.Printf("failed to connect to %q: %v", addr, err)
 			return ircError{&irc.Message{
 				Command: irc.ERR_PASSWDMISMATCH,
-				Params:  []string{dc.nick, fmt.Sprintf("Failed to connect to %q", dc.networkName)},
+				Params:  []string{dc.nick, fmt.Sprintf("Failed to connect to %q", dc.registration.networkName)},
 			}}
 		}
 
@@ -1360,10 +1359,10 @@ func (dc *downstreamConn) loadNetwork(ctx context.Context) error {
 			}}
 		}
 
-		dc.logger.Printf("auto-saving network %q", dc.networkName)
+		dc.logger.Printf("auto-saving network %q", dc.registration.networkName)
 		var err error
 		network, err = dc.user.createNetwork(ctx, &Network{
-			Addr:    dc.networkName,
+			Addr:    dc.registration.networkName,
 			Nick:    nick,
 			Enabled: true,
 		})
@@ -1391,6 +1390,8 @@ func (dc *downstreamConn) welcome(ctx context.Context) error {
 		return err
 	}
 
+	dc.registration = nil
+
 	dc.updateSupportedCaps()
 
 	if uc := dc.upstream(); uc != nil {