fix: GNAP header inspection bug

pkg/controller/mw/authmw/gnapmw/gnap_middleware.go

@@ -69,13 +69,12 @@ type HTTPHandler interface {
 
 // Accept checks if the request can be handled by the GNAP middleware.
 func (mw *Middleware) Accept(req *http.Request) bool {
-	if v, ok := req.Header["Authorization"]; ok {
-		for _, h := range v {
-			if strings.Contains(h, gnapToken) {
-				logger.Debugf("Accept: %v is true", v)
+	v := req.Header.Values("Authorization")
+	for _, h := range v {
+		if strings.Contains(h, gnapToken) {
+			logger.Debugf("Accept: %v is true", v)
 
-				return true
-			}
+			return true
 		}
 	}
 
@@ -108,9 +107,20 @@ type gnapHandler struct {
 
 // ServeHTTP authorizes an incoming HTTP request using GNAP.
 func (h *gnapHandler) ServeHTTP(w http.ResponseWriter, req *http.Request) {
-	tokenHeader := strings.Split(strings.Trim(req.Header.Get("Authorization"), " "), " ")
+	var tokenHeader string
 
-	if len(tokenHeader) < 2 || tokenHeader[0] != gnapToken {
+	v := req.Header.Values("Authorization")
+	for _, h := range v {
+		if strings.Contains(h, gnapToken) {
+			tokenHeader = h
+
+			break
+		}
+	}
+
+	tokenHeaderSplit := strings.Split(strings.Trim(tokenHeader, " "), " ")
+
+	if len(tokenHeaderSplit) < 2 || tokenHeaderSplit[0] != gnapToken {
 		http.Error(w, "unauthorized", http.StatusUnauthorized)
 
 		return
@@ -121,7 +131,7 @@ func (h *gnapHandler) ServeHTTP(w http.ResponseWriter, req *http.Request) {
 			Key: h.clientKey,
 		},
 		Proof:       proofType,
-		AccessToken: tokenHeader[1],
+		AccessToken: tokenHeaderSplit[1],
 	}
 
 	resp, err := h.client.Introspect(introspectReq)

pkg/controller/mw/authmw/gnapmw/gnap_middleware_test.go

@@ -167,6 +167,58 @@ func TestMiddleware(t *testing.T) {
 		require.Equal(t, http.StatusOK, rr.Code)
 	})
 
+	t.Run("should call next handler if request is authorized "+
+		"(GNAP token is second value in Authorization header)", func(t *testing.T) {
+		ctrl := gomock.NewController(t)
+
+		privKey, err := ecdsa.GenerateKey(elliptic.P256(), rand.Reader)
+
+		privJWK := &jwk.JWK{
+			JSONWebKey: jose.JSONWebKey{
+				Key:       privKey,
+				KeyID:     "key1",
+				Algorithm: "ES256",
+			},
+			Kty: "EC",
+			Crv: "P-256",
+		}
+
+		pubJWK := jwk.JWK{
+			JSONWebKey: privJWK.Public(),
+			Kty:        "EC",
+			Crv:        "P-256",
+		}
+
+		require.NoError(t, err)
+		client := NewMockGNAPRSClient(ctrl)
+		client.EXPECT().Introspect(gomock.Any()).Return(&gnap.IntrospectResponse{Active: true, Key: &gnap.ClientKey{
+			JWK: pubJWK,
+		}}, nil)
+
+		mVerifier := NewMockGNAPVerifier(ctrl)
+		mVerifier.EXPECT().Verify(gomock.Any()).Times(1)
+
+		mw, err := gnapmw.NewMiddleware(client, &pubJWK, func(req *http.Request) gnapmw.GNAPVerifier {
+			return mVerifier
+		}, false)
+		require.NoError(t, err)
+
+		next := NewMockHTTPHandler(ctrl)
+		next.EXPECT().ServeHTTP(gomock.Any(), gomock.Any()).Times(1)
+
+		req, err := http.NewRequestWithContext(context.Background(), "", "", nil)
+		require.NoError(t, err)
+
+		req.Header.Add("Authorization", "Some other token")
+		req.Header.Add("Authorization", "GNAP token")
+
+		rr := httptest.NewRecorder()
+
+		mw.Middleware()(next).ServeHTTP(rr, req)
+
+		require.Equal(t, http.StatusOK, rr.Code)
+	})
+
 	t.Run("should return 401 Unauthorized if request is unauthorized due to signature error", func(t *testing.T) {
 		ctrl := gomock.NewController(t)
 

pkg/controller/mw/authmw/zcapmw/zcap_middleware.go

@@ -62,9 +62,9 @@ type Middleware struct {
 
 // Accept checks if middleware can handle auth for the given request.
 func (mw *Middleware) Accept(req *http.Request) bool {
-	_, ok := req.Header["Capability-Invocation"]
+	headerValues := req.Header.Values("Capability-Invocation")
 
-	return ok
+	return len(headerValues) > 0
 }
 
 // Middleware returns middleware func.