Xray-core: More robust browser header masquerading (chrome, firefox, edge) (#5802)

Fixes https://github.com/XTLS/Xray-core/issues/5800

transport/internet/grpc/dial.go

@@ -10,8 +10,8 @@ import (
 	c "github.com/xtls/xray-core/common/ctx"
 	"github.com/xtls/xray-core/common/errors"
 	"github.com/xtls/xray-core/common/net"
-	"github.com/xtls/xray-core/common/session"
 	"github.com/xtls/xray-core/common/utils"
+	"github.com/xtls/xray-core/common/session"
 	"github.com/xtls/xray-core/transport/internet"
 	"github.com/xtls/xray-core/transport/internet/grpc/encoding"
 	"github.com/xtls/xray-core/transport/internet/reality"
@@ -191,8 +191,16 @@ func getGrpcClient(ctx context.Context, dest net.Destination, streamSettings *in
 	)
 	if err == nil {
 		userAgent := grpcSettings.UserAgent
-		if userAgent == "" {
+		// It's NOT recommended to set the UA of gRPC connections to that of real browsers, as they are fundamentally incapable of initiating real gRPC connections.
+		switch userAgent {
+		case "chrome", "":
 			userAgent = utils.ChromeUA
+		case "firefox":
+			userAgent = utils.FirefoxUA
+		case "edge":
+			userAgent = utils.MSEdgeUA
+		case "golang":
+			userAgent = ""
 		}
 		setUserAgent(conn, userAgent)
 		conn.Connect()

transport/internet/httpupgrade/dialer.go

@@ -96,9 +96,7 @@ func dialhttpUpgrade(ctx context.Context, dest net.Destination, streamSettings *
 	for key, value := range transportConfiguration.Header {
 		AddHeader(req.Header, key, value)
 	}
-	if req.Header.Get("User-Agent") == "" {
-		req.Header.Set("User-Agent", utils.ChromeUA)
-	}
+	utils.TryDefaultHeadersWith(req.Header, "ws")
 	req.Header.Set("Connection", "Upgrade")
 	req.Header.Set("Upgrade", "websocket")
 

transport/internet/reality/reality.go

@@ -223,7 +223,7 @@ func UClient(c net.Conn, config *Config, ctx context.Context, dest net.Destinati
 				if req == nil {
 					return
 				}
-				req.Header.Set("User-Agent", utils.ChromeUA)
+				utils.TryDefaultHeadersWith(req.Header, "nav")
 				if first && config.Show {
 					fmt.Printf("REALITY localAddr: %v\treq.UserAgent(): %v\n", localAddr, req.UserAgent())
 				}

transport/internet/splithttp/config.go

@@ -51,9 +51,7 @@ func (c *Config) GetRequestHeader() http.Header {
 	for k, v := range c.Headers {
 		header.Add(k, v)
 	}
-	if header.Get("User-Agent") == "" {
-		header.Set("User-Agent", utils.ChromeUA)
-	}
+	utils.TryDefaultHeadersWith(header, "fetch")
 	return header
 }
 

transport/internet/tls/ech.go

@@ -253,7 +253,7 @@ func dnsQuery(server string, domain string, sockopt *internet.SocketConfig) ([]b
 		}
 		req.Header.Set("Accept", "application/dns-message")
 		req.Header.Set("Content-Type", "application/dns-message")
-		req.Header.Set("User-Agent", utils.ChromeUA)
+		utils.TryDefaultHeadersWith(req.Header, "fetch")
 		req.Header.Set("X-Padding", utils.H2Base62Pad(crypto.RandBetween(100, 1000)))
 
 		resp, err := client.Do(req)

transport/internet/websocket/config.go

@@ -24,9 +24,7 @@ func (c *Config) GetRequestHeader() http.Header {
 	for k, v := range c.Header {
 		header.Add(k, v)
 	}
-	if header.Get("User-Agent") == "" {
-		header.Set("User-Agent", utils.ChromeUA)
-	}
+	utils.TryDefaultHeadersWith(header, "ws")
 	return header
 }