Enable logout redirection for reverse proxy setups

When authentication is handled externally by a reverse proxy or SSO provider,
users can be redirected to an external logout URL or relative path
defined on the reverse proxy to fully logout.

Author: eliroca

custom/conf/app.example.ini

@@ -463,6 +463,11 @@ INTERNAL_TOKEN =
 ;; Name of cookie used to store authentication information.
 ;COOKIE_REMEMBER_NAME = gitea_incredible
 ;;
+;; URL or path that Gitea should redirect users to *after* performing its own logout.
+;; Use this to redirect user to the external logout endpoint, if needed, when authentication is handled by a reverse proxy or SSO.
+;; Mellon example: REVERSE_PROXY_LOGOUT_REDIRECT = /mellon/logout?ReturnTo=/
+;REVERSE_PROXY_LOGOUT_REDIRECT =
+;;
 ;; Reverse proxy authentication header name of user name, email, and full name
 ;REVERSE_PROXY_AUTHENTICATION_USER = X-WEBAUTH-USER
 ;REVERSE_PROXY_AUTHENTICATION_EMAIL = X-WEBAUTH-EMAIL

modules/setting/security.go

@@ -25,6 +25,7 @@ var (
 	ReverseProxyAuthEmail              string
 	ReverseProxyAuthFullName           string
 	ReverseProxyLimit                  int
+	ReverseProxyLogoutRedirect         string
 	ReverseProxyTrustedProxies         []string
 	MinPasswordLength                  int
 	ImportLocalPaths                   bool
@@ -121,6 +122,7 @@ func loadSecurityFrom(rootCfg ConfigProvider) {
 	ReverseProxyAuthFullName = sec.Key("REVERSE_PROXY_AUTHENTICATION_FULL_NAME").MustString("X-WEBAUTH-FULLNAME")
 
 	ReverseProxyLimit = sec.Key("REVERSE_PROXY_LIMIT").MustInt(1)
+	ReverseProxyLogoutRedirect = sec.Key("REVERSE_PROXY_LOGOUT_REDIRECT").MustString("")
 	ReverseProxyTrustedProxies = sec.Key("REVERSE_PROXY_TRUSTED_PROXIES").Strings(",")
 	if len(ReverseProxyTrustedProxies) == 0 {
 		ReverseProxyTrustedProxies = []string{"127.0.0.0/8", "::1/128"}

routers/web/auth/auth.go

@@ -416,6 +416,14 @@ func SignOut(ctx *context.Context) {
 		})
 	}
 	HandleSignOut(ctx)
+	if setting.ReverseProxyLogoutRedirect != "" {
+		ctx.Redirect(setting.ReverseProxyLogoutRedirect)
+		return
+	}
+	if ctx.Req.Method == http.MethodGet {
+		ctx.Redirect(setting.AppSubURL + "/")
+		return
+	}
 	ctx.JSONRedirect(setting.AppSubURL + "/")
 }
 

routers/web/web.go

@@ -694,6 +694,7 @@ func registerWebRoutes(m *web.Router) {
 		m.Post("/recover_account", auth.ResetPasswdPost)
 		m.Get("/forgot_password", auth.ForgotPasswd)
 		m.Post("/forgot_password", auth.ForgotPasswdPost)
+		m.Get("/logout", auth.SignOut)
 		m.Post("/logout", auth.SignOut)
 		m.Get("/stopwatches", reqSignIn, user.GetStopwatches)
 		m.Get("/search_candidates", optExploreSignIn, user.SearchCandidates)

services/context/context.go

@@ -206,6 +206,8 @@ func Contexter() func(next http.Handler) http.Handler {
 			ctx.Data["ManifestData"] = setting.ManifestData
 			ctx.Data["AllLangs"] = translation.AllLangs()
 
+			ctx.Data["ReverseProxyLogoutRedirect"] = setting.ReverseProxyLogoutRedirect != ""
+
 			next.ServeHTTP(ctx.Resp, ctx.Req)
 		})
 	}

templates/base/head_navbar.tmpl

@@ -55,7 +55,7 @@
 					</div>
 
 					<div class="divider"></div>
-					<a class="item link-action" href data-url="{{AppSubUrl}}/user/logout">
+					<a class="item{{if not .ReverseProxyLogoutRedirect}} link-action" data-url={{else}}" href={{end}}"{{AppSubUrl}}/user/logout">
 						{{svg "octicon-sign-out"}}
 						{{ctx.Locale.Tr "sign_out"}}
 					</a>
@@ -128,7 +128,7 @@
 					</a>
 					{{end}}
 					<div class="divider"></div>
-					<a class="item link-action" href data-url="{{AppSubUrl}}/user/logout">
+					<a class="item{{if not .ReverseProxyLogoutRedirect}} link-action" data-url={{else}}" href={{end}}"{{AppSubUrl}}/user/logout">
 						{{svg "octicon-sign-out"}}
 						{{ctx.Locale.Tr "sign_out"}}
 					</a>

tests/integration/signout_test.go

@@ -7,10 +7,12 @@ import (
 	"net/http"
 	"testing"
 
+	"code.gitea.io/gitea/modules/setting"
+	"code.gitea.io/gitea/modules/test"
 	"code.gitea.io/gitea/tests"
 )
 
-func TestSignOut(t *testing.T) {
+func TestSignOut_Post(t *testing.T) {
 	defer tests.PrepareTestEnv(t)()
 
 	session := loginUser(t, "user2")
@@ -22,3 +24,42 @@ func TestSignOut(t *testing.T) {
 	req = NewRequest(t, "GET", "/user2/repo2")
 	session.MakeRequest(t, req, http.StatusNotFound)
 }
+
+func TestSignOut_Get(t *testing.T) {
+	defer tests.PrepareTestEnv(t)()
+
+	session := loginUser(t, "user2")
+
+	req := NewRequest(t, "GET", "/user/logout")
+	resp := session.MakeRequest(t, req, http.StatusSeeOther)
+
+	location := resp.Header().Get("Location")
+	if location != "/" {
+		t.Fatalf("expected redirect Location to '/', got %q", location)
+	}
+
+	// try to view a private repo, should fail
+	req = NewRequest(t, "GET", "/user2/repo2")
+	session.MakeRequest(t, req, http.StatusNotFound)
+}
+
+func TestSignOut_ReverseProxyLogoutRedirect(t *testing.T) {
+	defer tests.PrepareTestEnv(t)()
+
+	defer test.MockVariableValue(&setting.ReverseProxyLogoutRedirect, "/mellon/logout?ReturnTo=/")()
+
+	session := loginUser(t, "user2")
+
+	req := NewRequest(t, "GET", "/user/logout")
+	resp := session.MakeRequest(t, req, http.StatusSeeOther)
+
+	expected := "/mellon/logout?ReturnTo=/"
+	loc := resp.Header().Get("Location")
+	if loc != expected {
+		t.Fatalf("expected redirect to %q, got %q", expected, loc)
+	}
+
+	// try to view a private repo, should fail
+	req = NewRequest(t, "GET", "/user2/repo2")
+	session.MakeRequest(t, req, http.StatusNotFound)
+}