Use net.JoinHostPort and net.SplitHostPort for IPv6-safe host:port handling (#5836)

client/internal/profilemanager/config.go

@@ -5,6 +5,7 @@ import (
 	"crypto/tls"
 	"encoding/json"
 	"fmt"
+	"net"
 	"net/url"
 	"os"
 	"os/user"
@@ -759,8 +760,7 @@ func UpdateOldManagementURL(ctx context.Context, config *Config, configPath stri
 		return config, nil
 	}
 
-	newURL, err := parseURL("Management URL", fmt.Sprintf("%s://%s:%d",
-		config.ManagementURL.Scheme, defaultManagementURL.Hostname(), 443))
+	newURL, err := parseURL("Management URL", fmt.Sprintf("%s://%s", config.ManagementURL.Scheme, net.JoinHostPort(defaultManagementURL.Hostname(), "443")))
 	if err != nil {
 		return nil, err
 	}

client/internal/relay/relay.go

@@ -6,6 +6,7 @@ import (
 	"errors"
 	"fmt"
 	"net"
+	"strconv"
 	"sync"
 	"time"
 
@@ -257,7 +258,7 @@ func (p *StunTurnProbe) probeTURN(ctx context.Context, uri *stun.URI) (addr stri
 		}
 	}()
 
-	turnServerAddr := fmt.Sprintf("%s:%d", uri.Host, uri.Port)
+	turnServerAddr := net.JoinHostPort(uri.Host, strconv.Itoa(uri.Port))
 
 	var conn net.PacketConn
 	switch uri.Proto {

client/internal/rosenpass/manager.go

@@ -259,6 +259,9 @@ func findRandomAvailableUDPPort() (int, error) {
 	}
 	defer conn.Close()
 
-	splitAddress := strings.Split(conn.LocalAddr().String(), ":")
-	return strconv.Atoi(splitAddress[len(splitAddress)-1])
+	_, portStr, err := net.SplitHostPort(conn.LocalAddr().String())
+	if err != nil {
+		return 0, fmt.Errorf("parse local address %s: %w", conn.LocalAddr(), err)
+	}
+	return strconv.Atoi(portStr)
 }

client/internal/rosenpass/manager_test.go

@@ -0,0 +1,14 @@
+package rosenpass
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/require"
+)
+
+func TestFindRandomAvailableUDPPort(t *testing.T) {
+	port, err := findRandomAvailableUDPPort()
+	require.NoError(t, err)
+	require.Greater(t, port, 0)
+	require.LessOrEqual(t, port, 65535)
+}