Fix upstream proxy appending `?` to requests

CHANGELOG.md

@@ -16,6 +16,7 @@
 
 ## Changes since v7.0.1
 
+- [#1115](https://github.com/oauth2-proxy/oauth2-proxy/pull/1115) Fix upstream proxy appending ? to requests (@JoelSpeed)
 - [#1117](https://github.com/oauth2-proxy/oauth2-proxy/pull/1117)  Deprecate GCP HealthCheck option (@JoelSpeed)
 - [#1104](https://github.com/oauth2-proxy/oauth2-proxy/pull/1104) Allow custom robots text pages (@JoelSpeed)
 - [#1045](https://github.com/oauth2-proxy/oauth2-proxy/pull/1045) Ensure redirect URI always has a scheme (@JoelSpeed)

pkg/upstream/http.go

@@ -153,6 +153,7 @@ func setProxyDirector(proxy *httputil.ReverseProxy) {
 		// use RequestURI so that we aren't unescaping encoded slashes in the request path
 		req.URL.Opaque = req.RequestURI
 		req.URL.RawQuery = ""
+		req.URL.ForceQuery = false
 	}
 }
 

pkg/upstream/http_test.go

@@ -140,6 +140,29 @@ var _ = Describe("HTTP Upstream Suite", func() {
 			},
 			expectedUpstream: "encodedSlashes",
 		}),
+		Entry("request a path with an empty query string", &httpUpstreamTableInput{
+			id:           "default",
+			serverAddr:   &serverAddr,
+			target:       "http://example.localhost/foo?",
+			method:       "GET",
+			body:         []byte{},
+			errorHandler: nil,
+			expectedResponse: testHTTPResponse{
+				code: 200,
+				header: map[string][]string{
+					contentType: {applicationJSON},
+				},
+				request: testHTTPRequest{
+					Method:     "GET",
+					URL:        "http://example.localhost/foo?",
+					Header:     map[string][]string{},
+					Body:       []byte{},
+					Host:       "example.localhost",
+					RequestURI: "http://example.localhost/foo?",
+				},
+			},
+			expectedUpstream: "default",
+		}),
 		Entry("when the request has a body", &httpUpstreamTableInput{
 			id:           "requestWithBody",
 			serverAddr:   &serverAddr,