Add single sign-on support via SSPI on Windows (#8463)

* Add single sign-on support via SSPI on Windows

* Ensure plugins implement interface

* Ensure plugins implement interface

* Move functions used only by the SSPI auth method to sspi_windows.go

* Field SSPISeparatorReplacement of AuthenticationForm should not be required via binding, as binding will insist the field is non-empty even if another login type is selected

* Fix breaking of oauth authentication on download links. Do not create new session with SSPI authentication on download links.

* Update documentation for the new 'SPNEGO with SSPI' login source

* Mention in documentation that ROOT_URL should contain the FQDN of the server

* Make sure that Contexter is not checking for active login sources when the ORM engine is not initialized (eg. when installing)

* Always initialize and free SSO methods, even if they are not enabled, as a method can be activated while the app is running (from Authentication sources)

* Add option in SSPIConfig for removing of domains from logon names

* Update helper text for StripDomainNames option

* Make sure handleSignIn() is called after a new user object is created by SSPI auth method

* Remove default value from text of form field helper

Co-Authored-By: Lauris BH <lauris@nix.lv>

* Remove default value from text of form field helper

Co-Authored-By: Lauris BH <lauris@nix.lv>

* Remove default value from text of form field helper

Co-Authored-By: Lauris BH <lauris@nix.lv>

* Only make a query to the DB to check if SSPI is enabled on handlers that need that information for templates

* Remove code duplication

* Log errors in ActiveLoginSources

Co-Authored-By: Lauris BH <lauris@nix.lv>

* Revert suffix of randomly generated E-mails for Reverse proxy authentication

Co-Authored-By: Lauris BH <lauris@nix.lv>

* Revert unneeded white-space change in template

Co-Authored-By: Lauris BH <lauris@nix.lv>

* Add copyright comments at the top of new files

* Use loopback name for randomly generated emails

* Add locale tag for the SSPISeparatorReplacement field with proper casing

* Revert casing of SSPISeparatorReplacement field in locale file, moving it up, next to other form fields

* Update docs/content/doc/features/authentication.en-us.md

Co-Authored-By: guillep2k <18600385+guillep2k@users.noreply.github.com>

* Remove Priority() method and define the order in which SSO auth methods should be executed in one place

* Log authenticated username only if it's not empty

* Rephrase helper text for automatic creation of users

* Return error if more than one active SSPI auth source is found

* Change newUser() function to return error, letting caller log/handle the error

* Move isPublicResource, isPublicPage and handleSignIn functions outside SSPI auth method to allow other SSO methods to reuse them if needed

* Refactor initialization of the list containing SSO auth methods

* Validate SSPI settings on POST

* Change SSPI to only perform authentication on its own login page, API paths and download links. Leave Toggle middleware to redirect non authenticated users to login page

* Make 'Default language' in SSPI config empty, unless changed by admin

* Show error if admin tries to add a second authentication source of type SSPI

* Simplify declaration of global variable

* Rebuild gitgraph.js on Linux

* Make sure config values containing only whitespace are not accepted

1 files changed, 33 insertions, 0 deletions

diff --git a/modules/auth/sso/interface.go b/modules/auth/sso/interface.go
new file mode 100644
index 0000000000..89cc227e79
--- /dev/null
+++ b/modules/auth/sso/interface.go
@@ -0,0 +1,33 @@
+// Copyright 2019 The Gitea Authors. All rights reserved.
+// Use of this source code is governed by a MIT-style
+// license that can be found in the LICENSE file.
+
+package sso
+
+import (
+	"code.gitea.io/gitea/models"
+
+	"gitea.com/macaron/macaron"
+	"gitea.com/macaron/session"
+)
+
+// SingleSignOn represents a SSO authentication method (plugin) for HTTP requests.
+type SingleSignOn interface {
+	// Init should be called exactly once before using any of the other methods,
+	// in order to allow the plugin to allocate necessary resources
+	Init() error
+
+	// Free should be called exactly once before application closes, in order to
+	// give chance to the plugin to free any allocated resources
+	Free() error
+
+	// IsEnabled checks if the current SSO method has been enabled in settings.
+	IsEnabled() bool
+
+	// VerifyAuthData tries to verify the SSO authentication data contained in the request.
+	// If verification is successful returns either an existing user object (with id > 0)
+	// or a new user object (with id = 0) populated with the information that was found
+	// in the authentication data (username or email).
+	// Returns nil if verification fails.
+	VerifyAuthData(ctx *macaron.Context, sess session.Store) *models.User
+}