* Fix s3 auth with proxy request (#7403)

* * Fix s3 auth with proxy request

* * 6649 Add unit test for signature v4

* address comments

* fix for tests

* ipv6

* address comments

* setting scheme

Works for both cases (direct HTTPS and behind proxy)

* trim for ipv6

* Corrected Scheme Precedence Order

* trim

* accurate

---------

Co-authored-by: chrislu <chris.lu@gmail.com>
Co-authored-by: Chris Lu <chrislusf@users.noreply.github.com>

3 files changed, 223 insertions, 33 deletions

diff --git a/weed/s3api/auth_signature_v4.go b/weed/s3api/auth_signature_v4.go
index d0297d623..4d273de6a 100644
--- a/weed/s3api/auth_signature_v4.go
+++ b/weed/s3api/auth_signature_v4.go
@@ -591,44 +591,83 @@ func extractSignedHeaders(signedHeaders []string, r *http.Request) (http.Header,
 
 // extractHostHeader returns the value of host header if available.
 func extractHostHeader(r *http.Request) string {
-	// Check for X-Forwarded-Host header first, which is set by reverse proxies
-	if forwardedHost := r.Header.Get("X-Forwarded-Host"); forwardedHost != "" {
-		// Check if X-Forwarded-Host already contains a port
-		// This handles proxies (like Traefik, HAProxy) that include port in X-Forwarded-Host
-		if _, _, err := net.SplitHostPort(forwardedHost); err == nil {
-			// X-Forwarded-Host already contains a port (e.g., "example.com:8443" or "[::1]:8080")
-			// Use it as-is
-			return forwardedHost
-		}
-
-		// An IPv6 address literal must be enclosed in square brackets.
-		if ip := net.ParseIP(forwardedHost); ip != nil && strings.Contains(forwardedHost, ":") {
-			forwardedHost = "[" + forwardedHost + "]"
+	forwardedHost := r.Header.Get("X-Forwarded-Host")
+	forwardedPort := r.Header.Get("X-Forwarded-Port")
+	forwardedProto := r.Header.Get("X-Forwarded-Proto")
+
+	// Determine the effective scheme with correct order of precedence:
+	// 1. X-Forwarded-Proto (most authoritative, reflects client's original protocol)
+	// 2. r.TLS (authoritative for direct connection to server)
+	// 3. r.URL.Scheme (fallback, may not always be set correctly)
+	// 4. Default to "http"
+	scheme := "http"
+	if r.URL.Scheme != "" {
+		scheme = r.URL.Scheme
+	}
+	if r.TLS != nil {
+		scheme = "https"
+	}
+	if forwardedProto != "" {
+		scheme = forwardedProto
+	}
+
+	var host, port string
+	if forwardedHost != "" {
+		// X-Forwarded-Host can be a comma-separated list of hosts when there are multiple proxies.
+		// Use only the first host in the list and trim spaces for robustness.
+		if comma := strings.Index(forwardedHost, ","); comma != -1 {
+			host = strings.TrimSpace(forwardedHost[:comma])
+		} else {
+			host = strings.TrimSpace(forwardedHost)
 		}
-
-		// X-Forwarded-Host doesn't contain a port, check if X-Forwarded-Port is provided
-		if forwardedPort := r.Header.Get("X-Forwarded-Port"); forwardedPort != "" {
-			// Determine the protocol to check for standard ports
-			proto := strings.ToLower(r.Header.Get("X-Forwarded-Proto"))
-			// Only add port if it's not the standard port for the protocol
-			if (proto == "https" && forwardedPort != "443") || (proto != "https" && forwardedPort != "80") {
-				return forwardedHost + ":" + forwardedPort
+		port = forwardedPort
+		if h, p, err := net.SplitHostPort(host); err == nil {
+			host = h
+			if port == "" {
+				port = p
 			}
 		}
-		// Using reverse proxy with X-Forwarded-Host (standard port or no port forwarded).
-		return forwardedHost
+	} else {
+		host = r.Host
+		if host == "" {
+			host = r.URL.Host
+		}
+		if h, p, err := net.SplitHostPort(host); err == nil {
+			host = h
+			port = p
+		}
 	}
 
-	hostHeaderValue := r.Host
-	// For standard requests, this should be fine.
-	if r.Host != "" {
-		return hostHeaderValue
+	// If we have a non-default port, join it with the host.
+	// net.JoinHostPort will handle bracketing for IPv6.
+	if port != "" && !isDefaultPort(scheme, port) {
+		// Strip existing brackets before calling JoinHostPort, which automatically adds
+		// brackets for IPv6 addresses. This prevents double-bracketing like [[::1]]:8080.
+		// Using Trim handles both well-formed and malformed bracketed hosts.
+		host = strings.Trim(host, "[]")
+		return net.JoinHostPort(host, port)
 	}
-	// If no host header is found, then check for host URL value.
-	if r.URL.Host != "" {
-		hostHeaderValue = r.URL.Host
+
+	// No port or default port, just ensure host is correctly formatted (IPv6 brackets).
+	if strings.Contains(host, ":") && !strings.HasPrefix(host, "[") {
+		return "[" + host + "]"
+	}
+	return host
+}
+
+func isDefaultPort(scheme, port string) bool {
+	if port == "" {
+		return true
+	}
+
+	switch port {
+	case "80":
+		return strings.EqualFold(scheme, "http")
+	case "443":
+		return strings.EqualFold(scheme, "https")
+	default:
+		return false
 	}
-	return hostHeaderValue
 }
 
 // getScope generate a string of a specific date, an AWS region, and a service.
diff --git a/weed/s3api/auth_signature_v4_test.go b/weed/s3api/auth_signature_v4_test.go
index 16f3840c0..6850e9d2b 100644
--- a/weed/s3api/auth_signature_v4_test.go
+++ b/weed/s3api/auth_signature_v4_test.go
@@ -216,12 +216,12 @@ func TestExtractHostHeader(t *testing.T) {
 			expected:       "[2001:db8::1]:8080",
 		},
 		{
-			name:           "IPv6 full address with brackets and port",
+			name:           "IPv6 full address with brackets and default port (should strip port)",
 			hostHeader:     "backend:8333",
 			forwardedHost:  "[2001:db8:85a3::8a2e:370:7334]:443",
 			forwardedPort:  "443",
 			forwardedProto: "https",
-			expected:       "[2001:db8:85a3::8a2e:370:7334]:443",
+			expected:       "[2001:db8:85a3::8a2e:370:7334]",
 		},
 		{
 			name:           "IPv4-mapped IPv6 address without brackets, should add brackets with port",
diff --git a/weed/s3api/auto_signature_v4_test.go b/weed/s3api/auto_signature_v4_test.go
index d31294c99..6039081a1 100644
--- a/weed/s3api/auto_signature_v4_test.go
+++ b/weed/s3api/auto_signature_v4_test.go
@@ -392,6 +392,125 @@ func TestSignatureV4WithForwardedPrefixTrailingSlash(t *testing.T) {
 	}
 }
 
+func TestSignatureV4WithoutProxy(t *testing.T) {
+	tests := []struct {
+		name         string
+		host         string
+		proto        string
+		expectedHost string
+	}{
+		{
+			name:         "HTTP with non-standard port",
+			host:         "backend:8333",
+			proto:        "http",
+			expectedHost: "backend:8333",
+		},
+		{
+			name:         "HTTPS with non-standard port",
+			host:         "backend:8333",
+			proto:        "https",
+			expectedHost: "backend:8333",
+		},
+		{
+			name:         "HTTP with standard port",
+			host:         "backend:80",
+			proto:        "http",
+			expectedHost: "backend",
+		},
+		{
+			name:         "HTTPS with standard port",
+			host:         "backend:443",
+			proto:        "https",
+			expectedHost: "backend",
+		},
+		{
+			name:         "HTTP without port",
+			host:         "backend",
+			proto:        "http",
+			expectedHost: "backend",
+		},
+		{
+			name:         "HTTPS without port",
+			host:         "backend",
+			proto:        "https",
+			expectedHost: "backend",
+		},
+		{
+			name:         "IPv6 HTTP with non-standard port",
+			host:         "[::1]:8333",
+			proto:        "http",
+			expectedHost: "[::1]:8333",
+		},
+		{
+			name:         "IPv6 HTTPS with non-standard port",
+			host:         "[::1]:8333",
+			proto:        "https",
+			expectedHost: "[::1]:8333",
+		},
+		{
+			name:         "IPv6 HTTP with standard port",
+			host:         "[::1]:80",
+			proto:        "http",
+			expectedHost: "[::1]",
+		},
+		{
+			name:         "IPv6 HTTPS with standard port",
+			host:         "[::1]:443",
+			proto:        "https",
+			expectedHost: "[::1]",
+		},
+		{
+			name:         "IPv6 HTTP without port",
+			host:         "::1",
+			proto:        "http",
+			expectedHost: "[::1]",
+		},
+		{
+			name:         "IPv6 HTTPS without port",
+			host:         "::1",
+			proto:        "https",
+			expectedHost: "[::1]",
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			iam := newTestIAM()
+
+			// Create a request
+			r, err := newTestRequest("GET", tt.proto+"://"+tt.host+"/test-bucket/test-object", 0, nil)
+			if err != nil {
+				t.Fatalf("Failed to create test request: %v", err)
+			}
+
+			// Set the mux variables manually since we're not going through the actual router
+			r = mux.SetURLVars(r, map[string]string{
+				"bucket": "test-bucket",
+				"object": "test-object",
+			})
+
+			// Set forwarded headers
+			r.Header.Set("Host", tt.host)
+			
+			// First, verify that extractHostHeader returns the expected value
+			extractedHost := extractHostHeader(r)
+			if extractedHost != tt.expectedHost {
+				t.Errorf("extractHostHeader() = %q, want %q", extractedHost, tt.expectedHost)
+			}
+
+			// Sign the request with the expected host header
+			// We need to temporarily modify the Host header for signing
+			signV4WithPath(r, "AKIAIOSFODNN7EXAMPLE", "wJalrXUtnFEMI/K7MDENG/bPxRfiCYEXAMPLEKEY", r.URL.Path)
+
+			// Test signature verification
+			_, _, errCode := iam.doesSignatureMatch(r)
+			if errCode != s3err.ErrNone {
+				t.Errorf("Expected successful signature validation, got error: %v (code: %d)", errCode, int(errCode))
+			}
+		})
+	}
+}
+
 // Test X-Forwarded-Port support for reverse proxy scenarios
 func TestSignatureV4WithForwardedPort(t *testing.T) {
 	tests := []struct {
@@ -468,6 +587,38 @@ func TestSignatureV4WithForwardedPort(t *testing.T) {
 			expectedHost:   "example.com:9000",
 		},
 		{
+			name:           "X-Forwarded-Host with standard https port already included (Traefik/HAProxy style)",
+			host:           "backend:443",
+			forwardedHost:  "127.0.0.1:443",
+			forwardedPort:  "443",
+			forwardedProto: "https",
+			expectedHost:   "127.0.0.1",
+		},
+		{
+			name:           "X-Forwarded-Host with standard http port already included (Traefik/HAProxy style)",
+			host:           "backend:80",
+			forwardedHost:  "127.0.0.1:80",
+			forwardedPort:  "80",
+			forwardedProto: "http",
+			expectedHost:   "127.0.0.1",
+		},
+		{
+			name:           "IPv6 X-Forwarded-Host with standard https port already included (Traefik/HAProxy style)",
+			host:           "backend:443",
+			forwardedHost:  "[::1]:443",
+			forwardedPort:  "443",
+			forwardedProto: "https",
+			expectedHost:   "[::1]",
+		},
+		{
+			name:           "IPv6 X-Forwarded-Host with standard http port already included (Traefik/HAProxy style)",
+			host:           "backend:80",
+			forwardedHost:  "[::1]:80",
+			forwardedPort:  "80",
+			forwardedProto: "http",
+			expectedHost:   "[::1]",
+		},
+		{
 			name:           "IPv6 with port in brackets",
 			host:           "backend:8333",
 			forwardedHost:  "[::1]:8080",