Do not add auth token to redirect requests which do not have the same

host as the inital request.

api/http_client.go

@@ -91,9 +91,17 @@ func AddAuthTokenHeader(rt http.RoundTripper, cfg tokenGetter) http.RoundTripper
 	return &funcTripper{roundTrip: func(req *http.Request) (*http.Response, error) {
 		// If the header is already set in the request, don't overwrite it.
 		if req.Header.Get(authorization) == "" {
-			hostname := ghinstance.NormalizeHostname(getHost(req))
-			if token, _ := cfg.Token(hostname); token != "" {
-				req.Header.Set(authorization, fmt.Sprintf("token %s", token))
+			var redirectHostnameChange bool
+			if req.Response != nil && req.Response.Request != nil {
+				redirectHostnameChange = getHost(req) != getHost(req.Response.Request)
+			}
+			// Only set header if an initial request or redirect request to the same host as the initial request.
+			// If the host has changed during a redirect do not add the authentication token header.
+			if !redirectHostnameChange {
+				hostname := ghinstance.NormalizeHostname(getHost(req))
+				if token, _ := cfg.Token(hostname); token != "" {
+					req.Header.Set(authorization, fmt.Sprintf("token %s", token))
+				}
 			}
 		}
 		return rt.RoundTrip(req)
@@ -128,5 +136,5 @@ func getHost(r *http.Request) string {
 	if r.Host != "" {
 		return r.Host
 	}
-	return r.URL.Hostname()
+	return r.URL.Host
 }

api/http_client_test.go

@@ -6,6 +6,7 @@ import (
 	"net/http/httptest"
 	"os"
 	"regexp"
+	"strings"
 	"testing"
 
 	"github.com/MakeNowJust/heredoc"
@@ -200,6 +201,40 @@ func TestNewHTTPClient(t *testing.T) {
 	}
 }
 
+func TestHTTPClientRedirectAuthenticationHeaderHandling(t *testing.T) {
+	var request *http.Request
+	server := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		request = r
+		w.WriteHeader(http.StatusNoContent)
+	}))
+	defer server.Close()
+
+	var redirectRequest *http.Request
+	redirectServer := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		redirectRequest = r
+		http.Redirect(w, r, server.URL, http.StatusFound)
+	}))
+	defer redirectServer.Close()
+
+	client, err := NewHTTPClient(HTTPClientOptions{
+		Config: tinyConfig{
+			fmt.Sprintf("%s:oauth_token", strings.TrimPrefix(redirectServer.URL, "http://")): "REDIRECT-TOKEN",
+			fmt.Sprintf("%s:oauth_token", strings.TrimPrefix(server.URL, "http://")):         "TOKEN",
+		},
+	})
+	require.NoError(t, err)
+
+	req, err := http.NewRequest("GET", redirectServer.URL, nil)
+	require.NoError(t, err)
+
+	res, err := client.Do(req)
+	require.NoError(t, err)
+
+	assert.Equal(t, "token REDIRECT-TOKEN", redirectRequest.Header.Get(authorization))
+	assert.Equal(t, "", request.Header.Get(authorization))
+	assert.Equal(t, 204, res.StatusCode)
+}
+
 type tinyConfig map[string]string
 
 func (c tinyConfig) Token(host string) (string, string) {