Merge 5ea1f87e8838da6ff3d02435f979778342fe1af4 into 9914178584e42458ff7d23891463a880f58c9d86

* Fix ClientIP calculation by concatenating all RemoteIPHeaders values

* test: used http.MethodGet instead constants and fix lints

* lint error fixed

* Refactor ClientIP X-Forwarded-For tests

---------

Co-authored-by: Bo-Yi Wu <appleboy.tw@gmail.com>

context.go

@@ -989,7 +989,8 @@ func (c *Context) ClientIP() string {
 
 	if trusted && c.engine.ForwardedByClientIP && c.engine.RemoteIPHeaders != nil {
 		for _, headerName := range c.engine.RemoteIPHeaders {
-			ip, valid := c.engine.validateHeader(c.requestHeader(headerName))
+			headerValue := strings.Join(c.Request.Header.Values(headerName), ",")
+			ip, valid := c.engine.validateHeader(headerValue)
 			if valid {
 				return ip
 			}
@@ -1219,7 +1220,14 @@ func (c *Context) String(code int, format string, values ...any) {
 }
 
 // Redirect returns an HTTP redirect to the specific location.
+// When the 'location' parameter is empty, it poses a potential security risk.
+// Avoid bringing potential security risks into the production environment.
 func (c *Context) Redirect(code int, location string) {
+	if location == "" {
+		debugPrint(`[WARNING] When the 'location' parameter is empty, it poses a potential security risk. Please input a secure redirection URL to ensure safe operation.`)
+	}
+
+
 	c.Render(-1, render.Redirect{
 		Code:     code,
 		Location: location,

context_test.go

@@ -1143,6 +1143,37 @@ func TestContextRenderNoContentIndentedJSON(t *testing.T) {
 	assert.Equal(t, "application/json; charset=utf-8", w.Header().Get("Content-Type"))
 }
 
+func TestContextClientIPWithMultipleHeaders(t *testing.T) {
+	c, _ := CreateTestContext(httptest.NewRecorder())
+	c.Request, _ = http.NewRequest(http.MethodGet, "/test", nil)
+
+	// Multiple X-Forwarded-For headers
+	c.Request.Header.Add("X-Forwarded-For", "1.2.3.4, "+localhostIP)
+	c.Request.Header.Add("X-Forwarded-For", "5.6.7.8")
+	c.Request.RemoteAddr = localhostIP + ":1234"
+
+	c.engine.ForwardedByClientIP = true
+	c.engine.RemoteIPHeaders = []string{"X-Forwarded-For"}
+	_ = c.engine.SetTrustedProxies([]string{localhostIP})
+
+	// Should return 5.6.7.8 (last non-trusted IP)
+	assert.Equal(t, "5.6.7.8", c.ClientIP())
+}
+
+func TestContextClientIPWithSingleHeader(t *testing.T) {
+	c, _ := CreateTestContext(httptest.NewRecorder())
+	c.Request, _ = http.NewRequest(http.MethodGet, "/test", nil)
+	c.Request.Header.Set("X-Forwarded-For", "1.2.3.4, "+localhostIP)
+	c.Request.RemoteAddr = localhostIP + ":1234"
+
+	c.engine.ForwardedByClientIP = true
+	c.engine.RemoteIPHeaders = []string{"X-Forwarded-For"}
+	_ = c.engine.SetTrustedProxies([]string{localhostIP})
+
+	// Should return 1.2.3.4
+	assert.Equal(t, "1.2.3.4", c.ClientIP())
+}
+
 // Tests that the response is serialized as Secure JSON
 // and Content-Type is set to application/json
 func TestContextRenderSecureJSON(t *testing.T) {
@@ -1548,6 +1579,7 @@ func TestContextRenderRedirectAll(t *testing.T) {
 	assert.Panics(t, func() { c.Redirect(309, "/resource") })
 	assert.NotPanics(t, func() { c.Redirect(http.StatusMultipleChoices, "/resource") })
 	assert.NotPanics(t, func() { c.Redirect(http.StatusPermanentRedirect, "/resource") })
+	assert.NotPanics(t, func() { c.Redirect(http.StatusTemporaryRedirect, "")})
 }
 
 func TestContextNegotiationWithJSON(t *testing.T) {
@@ -1910,7 +1942,7 @@ func TestContextClientIP(t *testing.T) {
 	resetContextForClientIPTests(c)
 
 	// IPv6 support
-	c.Request.RemoteAddr = "[::1]:12345"
+	c.Request.RemoteAddr = fmt.Sprintf("[%s]:12345", localhostIPv6)
 	assert.Equal(t, "20.20.20.20", c.ClientIP())
 
 	resetContextForClientIPTests(c)
@@ -3212,7 +3244,7 @@ func TestContextCopyShouldNotCancel(t *testing.T) {
 	}()
 
 	addr := strings.Split(l.Addr().String(), ":")
-	res, err := http.Get(fmt.Sprintf("http://127.0.0.1:%s/", addr[len(addr)-1]))
+	res, err := http.Get(fmt.Sprintf("http://%s:%s/", localhostIP, addr[len(addr)-1]))
 	if err != nil {
 		t.Error(fmt.Errorf("request error: %w", err))
 		return

docs/doc.md

@@ -1555,6 +1555,8 @@ Gin allows only one html.Template by default. Check [a multitemplate render](htt
 
 Issuing a HTTP redirect is easy. Both internal and external locations are supported.
 
+Note: When the location is empty, there is a security risk. Please do not bring it to production
+
 ```go
 r.GET("/test", func(c *gin.Context) {
   c.Redirect(http.StatusMovedPermanently, "http://www.google.com/")

gin_test.go

@@ -83,7 +83,7 @@ func TestLoadHTMLGlobDebugMode(t *testing.T) {
 }
 
 func TestH2c(t *testing.T) {
-	ln, err := net.Listen("tcp", "127.0.0.1:0")
+	ln, err := net.Listen("tcp", localhostIP+":0")
 	if err != nil {
 		t.Error(err)
 	}

utils.go

@@ -19,6 +19,12 @@ import (
 // BindKey indicates a default bind key.
 const BindKey = "_gin-gonic/gin/bindkey"
 
+// localhostIP indicates the default localhost IP address.
+const localhostIP = "127.0.0.1"
+
+// localhostIPv6 indicates the default localhost IPv6 address.
+const localhostIPv6 = "::1"
+
 // Bind is a helper function for given interface object and returns a Gin middleware.
 func Bind(val any) HandlerFunc {
 	value := reflect.ValueOf(val)