fix(csrf): skip trustedorigin for http request and check x-forwarded-proto for reverse proxy [BE-11832] (#713)

api/http/middlewares/plaintext_http_request.go

@@ -0,0 +1,36 @@
+package middlewares
+
+import (
+	"net/http"
+	"slices"
+
+	"github.com/gorilla/csrf"
+)
+
+var (
+	// Idempotent (safe) methods as defined by RFC7231 section 4.2.2.
+	safeMethods = []string{"GET", "HEAD", "OPTIONS", "TRACE"}
+)
+
+type plainTextHTTPRequestHandler struct {
+	next http.Handler
+}
+
+func (h *plainTextHTTPRequestHandler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
+	if slices.Contains(safeMethods, r.Method) {
+		h.next.ServeHTTP(w, r)
+		return
+	}
+
+	req := r
+	// If original request was HTTPS (via proxy), keep CSRF checks.
+	if xfproto := r.Header.Get("X-Forwarded-Proto"); xfproto != "https" {
+		req = csrf.PlaintextHTTPRequest(r)
+	}
+
+	h.next.ServeHTTP(w, req)
+}
+
+func PlaintextHTTPRequest(next http.Handler) http.Handler {
+	return &plainTextHTTPRequestHandler{next: next}
+}

api/http/server.go

@@ -349,7 +349,7 @@ func (server *Server) Start() error {
 			log.Info().Str("bind_address", server.BindAddress).Msg("starting HTTP server")
 			httpServer := &http.Server{
 				Addr:     server.BindAddress,
-				Handler:  handler,
+				Handler:  middlewares.PlaintextHTTPRequest(handler),
 				ErrorLog: errorLogger,
 			}
 

go.mod

@@ -27,7 +27,7 @@ require (
 	github.com/gofrs/uuid v4.2.0+incompatible
 	github.com/golang-jwt/jwt/v4 v4.5.2
 	github.com/google/go-cmp v0.6.0
-	github.com/gorilla/csrf v1.7.2
+	github.com/gorilla/csrf v1.7.3
 	github.com/gorilla/mux v1.8.1
 	github.com/gorilla/websocket v1.5.0
 	github.com/hashicorp/go-version v1.7.0

go.sum

@@ -311,8 +311,8 @@ github.com/google/shlex v0.0.0-20191202100458-e7afc7fbc510 h1:El6M4kTTCOh6aBiKaU
 github.com/google/shlex v0.0.0-20191202100458-e7afc7fbc510/go.mod h1:pupxD2MaaD3pAXIBCelhxNneeOaAeabZDe5s4K6zSpQ=
 github.com/google/uuid v1.6.0 h1:NIvaJDMOsjHA8n1jAhLSgzrAzy1Hgr+hNrb57e+94F0=
 github.com/google/uuid v1.6.0/go.mod h1:TIyPZe4MgqvfeYDBFedMoGGpEw/LqOeaOT+nhxU+yHo=
-github.com/gorilla/csrf v1.7.2 h1:oTUjx0vyf2T+wkrx09Trsev1TE+/EbDAeHtSTbtC2eI=
+github.com/gorilla/csrf v1.7.3 h1:BHWt6FTLZAb2HtWT5KDBf6qgpZzvtbp9QWDRKZMXJC0=
-github.com/gorilla/csrf v1.7.2/go.mod h1:F1Fj3KG23WYHE6gozCmBAezKookxbIvUJT+121wTuLk=
+github.com/gorilla/csrf v1.7.3/go.mod h1:F1Fj3KG23WYHE6gozCmBAezKookxbIvUJT+121wTuLk=
 github.com/gorilla/mux v1.7.0/go.mod h1:1lud6UwP+6orDFRuTfBEV8e9/aOM/c4fVVCaMa2zaAs=
 github.com/gorilla/mux v1.8.1 h1:TuBL49tXwgrFYWhqrNgrUNEY92u81SPhu7sTdzQEiWY=
 github.com/gorilla/mux v1.8.1/go.mod h1:AKf9I4AEqPTmMytcMc0KkNouC66V3BtZ4qD5fmWSiMQ=