Proxy LuCI responses without body rewriting

server/internal/httpapi/server.go

@@ -1,7 +1,6 @@
 package httpapi
 
 import (
-	"bytes"
 	"context"
 	"crypto/rand"
 	"crypto/tls"
@@ -9,7 +8,6 @@ import (
 	"encoding/json"
 	"errors"
 	"fmt"
-	"io"
 	"log"
 	"net/http"
 	"net/http/httputil"
@@ -1147,19 +1145,6 @@ func (a *App) proxyLuCI(w http.ResponseWriter, r *http.Request, deviceID, sessio
 			})
 		}
 		rewriteLuCIHeaders(resp.Header, prefix)
-		contentType := resp.Header.Get("Content-Type")
-		if !strings.Contains(contentType, "text/html") {
-			return nil
-		}
-		body, err := io.ReadAll(resp.Body)
-		if err != nil {
-			return err
-		}
-		_ = resp.Body.Close()
-		body = rewriteLuCIBody(body, prefix)
-		resp.Body = io.NopCloser(bytes.NewReader(body))
-		resp.ContentLength = int64(len(body))
-		resp.Header.Set("Content-Length", strconv.Itoa(len(body)))
 		return nil
 	}
 	proxy.ErrorHandler = func(w http.ResponseWriter, _ *http.Request, err error) {
@@ -1200,18 +1185,6 @@ func rewriteLuCIHeaders(header http.Header, prefix string) {
 	}
 }
 
-func rewriteLuCIBody(body []byte, prefix string) []byte {
-	for _, marker := range []string{`="/`, `'/`, `url(/`} {
-		replacement := marker[:len(marker)-1] + prefix + "/"
-		body = bytes.ReplaceAll(body, []byte(marker), []byte(replacement))
-	}
-	escapedPrefix := strings.ReplaceAll(prefix, "/", `\/`)
-	for _, root := range []string{`\/cgi-bin\/luci`, `\/luci-static`, `\/ubus\/`} {
-		body = bytes.ReplaceAll(body, []byte(root), []byte(escapedPrefix+root))
-	}
-	return body
-}
-
 func (a *App) handleCloseRemoteSession(w http.ResponseWriter, r *http.Request) {
 	deviceID, sessionID, ok := remoteSessionCloseIDsFromPath(r.URL.Path)
 	if !ok {

server/internal/httpapi/server_test.go

@@ -474,13 +474,12 @@ func TestLuCIProxyRequiresActiveSessionAndRewritesPaths(t *testing.T) {
 
 	body := requestText(t, http.MethodGet, srv.URL+"/luci/"+enrolled.DeviceID+"/"+session.ID+"/", "operator-test", nil, http.StatusOK)
 	prefix := "/luci/" + enrolled.DeviceID + "/" + session.ID
-	if !strings.Contains(body, `href="`+prefix+`/cgi-bin/luci/admin"`) || !strings.Contains(body, `href="`+prefix+`/luci-static/test.css"`) {
-		t.Fatalf("LuCI paths were not rewritten: %s", body)
+	if !strings.Contains(body, `href="/cgi-bin/luci/admin"`) || !strings.Contains(body, `href="/luci-static/test.css"`) {
+		t.Fatalf("LuCI body was unexpectedly modified: %s", body)
 	}
-	escapedPrefix := strings.ReplaceAll(prefix, "/", `\/`)
 	for _, path := range []string{`\/luci-static\/resources`, `\/cgi-bin\/luci`, `\/ubus\/`} {
-		if !strings.Contains(body, escapedPrefix+path) {
-			t.Fatalf("escaped LuCI path %s was not rewritten: %s", path, body)
+		if !strings.Contains(body, path) {
+			t.Fatalf("escaped LuCI path %s was unexpectedly modified: %s", path, body)
 		}
 	}